1 /* Optimize by combining instructions for GNU compiler.
2 Copyright (C) 1987-2016 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This module is essentially the "combiner" phase of the U. of Arizona
21 Portable Optimizer, but redone to work on our list-structured
22 representation for RTL instead of their string representation.
24 The LOG_LINKS of each insn identify the most recent assignment
25 to each REG used in the insn. It is a list of previous insns,
26 each of which contains a SET for a REG that is used in this insn
27 and not used or set in between. LOG_LINKs never cross basic blocks.
28 They were set up by the preceding pass (lifetime analysis).
30 We try to combine each pair of insns joined by a logical link.
31 We also try to combine triplets of insns A, B and C when C has
32 a link back to B and B has a link back to A. Likewise for a
33 small number of quadruplets of insns A, B, C and D for which
34 there's high likelihood of success.
36 LOG_LINKS does not have links for use of the CC0. They don't
37 need to, because the insn that sets the CC0 is always immediately
38 before the insn that tests it. So we always regard a branch
39 insn as having a logical link to the preceding insn. The same is true
40 for an insn explicitly using CC0.
42 We check (with use_crosses_set_p) to avoid combining in such a way
43 as to move a computation to a place where its value would be different.
45 Combination is done by mathematically substituting the previous
46 insn(s) values for the regs they set into the expressions in
47 the later insns that refer to these regs. If the result is a valid insn
48 for our target machine, according to the machine description,
49 we install it, delete the earlier insns, and update the data flow
50 information (LOG_LINKS and REG_NOTES) for what we did.
52 There are a few exceptions where the dataflow information isn't
53 completely updated (however this is only a local issue since it is
54 regenerated before the next pass that uses it):
56 - reg_live_length is not updated
57 - reg_n_refs is not adjusted in the rare case when a register is
58 no longer required in a computation
59 - there are extremely rare cases (see distribute_notes) when a
61 - a LOG_LINKS entry that refers to an insn with multiple SETs may be
62 removed because there is no way to know which register it was
65 To simplify substitution, we combine only when the earlier insn(s)
66 consist of only a single assignment. To simplify updating afterward,
67 we never combine when a subroutine call appears in the middle.
69 Since we do not represent assignments to CC0 explicitly except when that
70 is all an insn does, there is no LOG_LINKS entry in an insn that uses
71 the condition code for the insn that set the condition code.
72 Fortunately, these two insns must be consecutive.
73 Therefore, every JUMP_INSN is taken to have an implicit logical link
74 to the preceding insn. This is not quite right, since non-jumps can
75 also use the condition code; but in practice such insns would not
80 #include "coretypes.h"
95 #include "stor-layout.h"
97 #include "cfgcleanup.h"
98 /* Include expr.h after insn-config.h so we get HAVE_conditional_move. */
100 #include "insn-attr.h"
101 #include "rtlhooks-def.h"
103 #include "tree-pass.h"
104 #include "valtrack.h"
105 #include "rtl-iter.h"
106 #include "print-rtl.h"
108 /* Number of attempts to combine instructions in this function. */
110 static int combine_attempts
;
112 /* Number of attempts that got as far as substitution in this function. */
114 static int combine_merges
;
116 /* Number of instructions combined with added SETs in this function. */
118 static int combine_extras
;
120 /* Number of instructions combined in this function. */
122 static int combine_successes
;
124 /* Totals over entire compilation. */
126 static int total_attempts
, total_merges
, total_extras
, total_successes
;
128 /* combine_instructions may try to replace the right hand side of the
129 second instruction with the value of an associated REG_EQUAL note
130 before throwing it at try_combine. That is problematic when there
131 is a REG_DEAD note for a register used in the old right hand side
132 and can cause distribute_notes to do wrong things. This is the
133 second instruction if it has been so modified, null otherwise. */
135 static rtx_insn
*i2mod
;
137 /* When I2MOD is nonnull, this is a copy of the old right hand side. */
139 static rtx i2mod_old_rhs
;
141 /* When I2MOD is nonnull, this is a copy of the new right hand side. */
143 static rtx i2mod_new_rhs
;
145 struct reg_stat_type
{
146 /* Record last point of death of (hard or pseudo) register n. */
147 rtx_insn
*last_death
;
149 /* Record last point of modification of (hard or pseudo) register n. */
152 /* The next group of fields allows the recording of the last value assigned
153 to (hard or pseudo) register n. We use this information to see if an
154 operation being processed is redundant given a prior operation performed
155 on the register. For example, an `and' with a constant is redundant if
156 all the zero bits are already known to be turned off.
158 We use an approach similar to that used by cse, but change it in the
161 (1) We do not want to reinitialize at each label.
162 (2) It is useful, but not critical, to know the actual value assigned
163 to a register. Often just its form is helpful.
165 Therefore, we maintain the following fields:
167 last_set_value the last value assigned
168 last_set_label records the value of label_tick when the
169 register was assigned
170 last_set_table_tick records the value of label_tick when a
171 value using the register is assigned
172 last_set_invalid set to nonzero when it is not valid
173 to use the value of this register in some
176 To understand the usage of these tables, it is important to understand
177 the distinction between the value in last_set_value being valid and
178 the register being validly contained in some other expression in the
181 (The next two parameters are out of date).
183 reg_stat[i].last_set_value is valid if it is nonzero, and either
184 reg_n_sets[i] is 1 or reg_stat[i].last_set_label == label_tick.
186 Register I may validly appear in any expression returned for the value
187 of another register if reg_n_sets[i] is 1. It may also appear in the
188 value for register J if reg_stat[j].last_set_invalid is zero, or
189 reg_stat[i].last_set_label < reg_stat[j].last_set_label.
191 If an expression is found in the table containing a register which may
192 not validly appear in an expression, the register is replaced by
193 something that won't match, (clobber (const_int 0)). */
195 /* Record last value assigned to (hard or pseudo) register n. */
199 /* Record the value of label_tick when an expression involving register n
200 is placed in last_set_value. */
202 int last_set_table_tick
;
204 /* Record the value of label_tick when the value for register n is placed in
209 /* These fields are maintained in parallel with last_set_value and are
210 used to store the mode in which the register was last set, the bits
211 that were known to be zero when it was last set, and the number of
212 sign bits copies it was known to have when it was last set. */
214 unsigned HOST_WIDE_INT last_set_nonzero_bits
;
215 char last_set_sign_bit_copies
;
216 ENUM_BITFIELD(machine_mode
) last_set_mode
: 8;
218 /* Set nonzero if references to register n in expressions should not be
219 used. last_set_invalid is set nonzero when this register is being
220 assigned to and last_set_table_tick == label_tick. */
222 char last_set_invalid
;
224 /* Some registers that are set more than once and used in more than one
225 basic block are nevertheless always set in similar ways. For example,
226 a QImode register may be loaded from memory in two places on a machine
227 where byte loads zero extend.
229 We record in the following fields if a register has some leading bits
230 that are always equal to the sign bit, and what we know about the
231 nonzero bits of a register, specifically which bits are known to be
234 If an entry is zero, it means that we don't know anything special. */
236 unsigned char sign_bit_copies
;
238 unsigned HOST_WIDE_INT nonzero_bits
;
240 /* Record the value of the label_tick when the last truncation
241 happened. The field truncated_to_mode is only valid if
242 truncation_label == label_tick. */
244 int truncation_label
;
246 /* Record the last truncation seen for this register. If truncation
247 is not a nop to this mode we might be able to save an explicit
248 truncation if we know that value already contains a truncated
251 ENUM_BITFIELD(machine_mode
) truncated_to_mode
: 8;
255 static vec
<reg_stat_type
> reg_stat
;
257 /* One plus the highest pseudo for which we track REG_N_SETS.
258 regstat_init_n_sets_and_refs allocates the array for REG_N_SETS just once,
259 but during combine_split_insns new pseudos can be created. As we don't have
260 updated DF information in that case, it is hard to initialize the array
261 after growing. The combiner only cares about REG_N_SETS (regno) == 1,
262 so instead of growing the arrays, just assume all newly created pseudos
263 during combine might be set multiple times. */
265 static unsigned int reg_n_sets_max
;
267 /* Record the luid of the last insn that invalidated memory
268 (anything that writes memory, and subroutine calls, but not pushes). */
270 static int mem_last_set
;
272 /* Record the luid of the last CALL_INSN
273 so we can tell whether a potential combination crosses any calls. */
275 static int last_call_luid
;
277 /* When `subst' is called, this is the insn that is being modified
278 (by combining in a previous insn). The PATTERN of this insn
279 is still the old pattern partially modified and it should not be
280 looked at, but this may be used to examine the successors of the insn
281 to judge whether a simplification is valid. */
283 static rtx_insn
*subst_insn
;
285 /* This is the lowest LUID that `subst' is currently dealing with.
286 get_last_value will not return a value if the register was set at or
287 after this LUID. If not for this mechanism, we could get confused if
288 I2 or I1 in try_combine were an insn that used the old value of a register
289 to obtain a new value. In that case, we might erroneously get the
290 new value of the register when we wanted the old one. */
292 static int subst_low_luid
;
294 /* This contains any hard registers that are used in newpat; reg_dead_at_p
295 must consider all these registers to be always live. */
297 static HARD_REG_SET newpat_used_regs
;
299 /* This is an insn to which a LOG_LINKS entry has been added. If this
300 insn is the earlier than I2 or I3, combine should rescan starting at
303 static rtx_insn
*added_links_insn
;
305 /* Basic block in which we are performing combines. */
306 static basic_block this_basic_block
;
307 static bool optimize_this_for_speed_p
;
310 /* Length of the currently allocated uid_insn_cost array. */
312 static int max_uid_known
;
314 /* The following array records the insn_rtx_cost for every insn
315 in the instruction stream. */
317 static int *uid_insn_cost
;
319 /* The following array records the LOG_LINKS for every insn in the
320 instruction stream as struct insn_link pointers. */
325 struct insn_link
*next
;
328 static struct insn_link
**uid_log_links
;
330 #define INSN_COST(INSN) (uid_insn_cost[INSN_UID (INSN)])
331 #define LOG_LINKS(INSN) (uid_log_links[INSN_UID (INSN)])
333 #define FOR_EACH_LOG_LINK(L, INSN) \
334 for ((L) = LOG_LINKS (INSN); (L); (L) = (L)->next)
336 /* Links for LOG_LINKS are allocated from this obstack. */
338 static struct obstack insn_link_obstack
;
340 /* Allocate a link. */
342 static inline struct insn_link
*
343 alloc_insn_link (rtx_insn
*insn
, unsigned int regno
, struct insn_link
*next
)
346 = (struct insn_link
*) obstack_alloc (&insn_link_obstack
,
347 sizeof (struct insn_link
));
354 /* Incremented for each basic block. */
356 static int label_tick
;
358 /* Reset to label_tick for each extended basic block in scanning order. */
360 static int label_tick_ebb_start
;
362 /* Mode used to compute significance in reg_stat[].nonzero_bits. It is the
363 largest integer mode that can fit in HOST_BITS_PER_WIDE_INT. */
365 static machine_mode nonzero_bits_mode
;
367 /* Nonzero when reg_stat[].nonzero_bits and reg_stat[].sign_bit_copies can
368 be safely used. It is zero while computing them and after combine has
369 completed. This former test prevents propagating values based on
370 previously set values, which can be incorrect if a variable is modified
373 static int nonzero_sign_valid
;
376 /* Record one modification to rtl structure
377 to be undone by storing old_contents into *where. */
379 enum undo_kind
{ UNDO_RTX
, UNDO_INT
, UNDO_MODE
, UNDO_LINKS
};
385 union { rtx r
; int i
; machine_mode m
; struct insn_link
*l
; } old_contents
;
386 union { rtx
*r
; int *i
; struct insn_link
**l
; } where
;
389 /* Record a bunch of changes to be undone, up to MAX_UNDO of them.
390 num_undo says how many are currently recorded.
392 other_insn is nonzero if we have modified some other insn in the process
393 of working on subst_insn. It must be verified too. */
399 rtx_insn
*other_insn
;
402 static struct undobuf undobuf
;
404 /* Number of times the pseudo being substituted for
405 was found and replaced. */
407 static int n_occurrences
;
409 static rtx
reg_nonzero_bits_for_combine (const_rtx
, machine_mode
, const_rtx
,
411 unsigned HOST_WIDE_INT
,
412 unsigned HOST_WIDE_INT
*);
413 static rtx
reg_num_sign_bit_copies_for_combine (const_rtx
, machine_mode
, const_rtx
,
415 unsigned int, unsigned int *);
416 static void do_SUBST (rtx
*, rtx
);
417 static void do_SUBST_INT (int *, int);
418 static void init_reg_last (void);
419 static void setup_incoming_promotions (rtx_insn
*);
420 static void set_nonzero_bits_and_sign_copies (rtx
, const_rtx
, void *);
421 static int cant_combine_insn_p (rtx_insn
*);
422 static int can_combine_p (rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx_insn
*,
423 rtx_insn
*, rtx_insn
*, rtx
*, rtx
*);
424 static int combinable_i3pat (rtx_insn
*, rtx
*, rtx
, rtx
, rtx
, int, int, rtx
*);
425 static int contains_muldiv (rtx
);
426 static rtx_insn
*try_combine (rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx_insn
*,
428 static void undo_all (void);
429 static void undo_commit (void);
430 static rtx
*find_split_point (rtx
*, rtx_insn
*, bool);
431 static rtx
subst (rtx
, rtx
, rtx
, int, int, int);
432 static rtx
combine_simplify_rtx (rtx
, machine_mode
, int, int);
433 static rtx
simplify_if_then_else (rtx
);
434 static rtx
simplify_set (rtx
);
435 static rtx
simplify_logical (rtx
);
436 static rtx
expand_compound_operation (rtx
);
437 static const_rtx
expand_field_assignment (const_rtx
);
438 static rtx
make_extraction (machine_mode
, rtx
, HOST_WIDE_INT
,
439 rtx
, unsigned HOST_WIDE_INT
, int, int, int);
440 static rtx
extract_left_shift (rtx
, int);
441 static int get_pos_from_mask (unsigned HOST_WIDE_INT
,
442 unsigned HOST_WIDE_INT
*);
443 static rtx
canon_reg_for_combine (rtx
, rtx
);
444 static rtx
force_to_mode (rtx
, machine_mode
,
445 unsigned HOST_WIDE_INT
, int);
446 static rtx
if_then_else_cond (rtx
, rtx
*, rtx
*);
447 static rtx
known_cond (rtx
, enum rtx_code
, rtx
, rtx
);
448 static int rtx_equal_for_field_assignment_p (rtx
, rtx
, bool = false);
449 static rtx
make_field_assignment (rtx
);
450 static rtx
apply_distributive_law (rtx
);
451 static rtx
distribute_and_simplify_rtx (rtx
, int);
452 static rtx
simplify_and_const_int_1 (machine_mode
, rtx
,
453 unsigned HOST_WIDE_INT
);
454 static rtx
simplify_and_const_int (rtx
, machine_mode
, rtx
,
455 unsigned HOST_WIDE_INT
);
456 static int merge_outer_ops (enum rtx_code
*, HOST_WIDE_INT
*, enum rtx_code
,
457 HOST_WIDE_INT
, machine_mode
, int *);
458 static rtx
simplify_shift_const_1 (enum rtx_code
, machine_mode
, rtx
, int);
459 static rtx
simplify_shift_const (rtx
, enum rtx_code
, machine_mode
, rtx
,
461 static int recog_for_combine (rtx
*, rtx_insn
*, rtx
*);
462 static rtx
gen_lowpart_for_combine (machine_mode
, rtx
);
463 static enum rtx_code
simplify_compare_const (enum rtx_code
, machine_mode
,
465 static enum rtx_code
simplify_comparison (enum rtx_code
, rtx
*, rtx
*);
466 static void update_table_tick (rtx
);
467 static void record_value_for_reg (rtx
, rtx_insn
*, rtx
);
468 static void check_promoted_subreg (rtx_insn
*, rtx
);
469 static void record_dead_and_set_regs_1 (rtx
, const_rtx
, void *);
470 static void record_dead_and_set_regs (rtx_insn
*);
471 static int get_last_value_validate (rtx
*, rtx_insn
*, int, int);
472 static rtx
get_last_value (const_rtx
);
473 static int use_crosses_set_p (const_rtx
, int);
474 static void reg_dead_at_p_1 (rtx
, const_rtx
, void *);
475 static int reg_dead_at_p (rtx
, rtx_insn
*);
476 static void move_deaths (rtx
, rtx
, int, rtx_insn
*, rtx
*);
477 static int reg_bitfield_target_p (rtx
, rtx
);
478 static void distribute_notes (rtx
, rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx
, rtx
, rtx
);
479 static void distribute_links (struct insn_link
*);
480 static void mark_used_regs_combine (rtx
);
481 static void record_promoted_value (rtx_insn
*, rtx
);
482 static bool unmentioned_reg_p (rtx
, rtx
);
483 static void record_truncated_values (rtx
*, void *);
484 static bool reg_truncated_to_mode (machine_mode
, const_rtx
);
485 static rtx
gen_lowpart_or_truncate (machine_mode
, rtx
);
488 /* It is not safe to use ordinary gen_lowpart in combine.
489 See comments in gen_lowpart_for_combine. */
490 #undef RTL_HOOKS_GEN_LOWPART
491 #define RTL_HOOKS_GEN_LOWPART gen_lowpart_for_combine
493 /* Our implementation of gen_lowpart never emits a new pseudo. */
494 #undef RTL_HOOKS_GEN_LOWPART_NO_EMIT
495 #define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_for_combine
497 #undef RTL_HOOKS_REG_NONZERO_REG_BITS
498 #define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_for_combine
500 #undef RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES
501 #define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_for_combine
503 #undef RTL_HOOKS_REG_TRUNCATED_TO_MODE
504 #define RTL_HOOKS_REG_TRUNCATED_TO_MODE reg_truncated_to_mode
506 static const struct rtl_hooks combine_rtl_hooks
= RTL_HOOKS_INITIALIZER
;
509 /* Convenience wrapper for the canonicalize_comparison target hook.
510 Target hooks cannot use enum rtx_code. */
512 target_canonicalize_comparison (enum rtx_code
*code
, rtx
*op0
, rtx
*op1
,
513 bool op0_preserve_value
)
515 int code_int
= (int)*code
;
516 targetm
.canonicalize_comparison (&code_int
, op0
, op1
, op0_preserve_value
);
517 *code
= (enum rtx_code
)code_int
;
520 /* Try to split PATTERN found in INSN. This returns NULL_RTX if
521 PATTERN can not be split. Otherwise, it returns an insn sequence.
522 This is a wrapper around split_insns which ensures that the
523 reg_stat vector is made larger if the splitter creates a new
527 combine_split_insns (rtx pattern
, rtx_insn
*insn
)
532 ret
= split_insns (pattern
, insn
);
533 nregs
= max_reg_num ();
534 if (nregs
> reg_stat
.length ())
535 reg_stat
.safe_grow_cleared (nregs
);
539 /* This is used by find_single_use to locate an rtx in LOC that
540 contains exactly one use of DEST, which is typically either a REG
541 or CC0. It returns a pointer to the innermost rtx expression
542 containing DEST. Appearances of DEST that are being used to
543 totally replace it are not counted. */
546 find_single_use_1 (rtx dest
, rtx
*loc
)
549 enum rtx_code code
= GET_CODE (x
);
565 /* If the destination is anything other than CC0, PC, a REG or a SUBREG
566 of a REG that occupies all of the REG, the insn uses DEST if
567 it is mentioned in the destination or the source. Otherwise, we
568 need just check the source. */
569 if (GET_CODE (SET_DEST (x
)) != CC0
570 && GET_CODE (SET_DEST (x
)) != PC
571 && !REG_P (SET_DEST (x
))
572 && ! (GET_CODE (SET_DEST (x
)) == SUBREG
573 && REG_P (SUBREG_REG (SET_DEST (x
)))
574 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x
))))
575 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
576 == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x
)))
577 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
))))
580 return find_single_use_1 (dest
, &SET_SRC (x
));
584 return find_single_use_1 (dest
, &XEXP (x
, 0));
590 /* If it wasn't one of the common cases above, check each expression and
591 vector of this code. Look for a unique usage of DEST. */
593 fmt
= GET_RTX_FORMAT (code
);
594 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
598 if (dest
== XEXP (x
, i
)
599 || (REG_P (dest
) && REG_P (XEXP (x
, i
))
600 && REGNO (dest
) == REGNO (XEXP (x
, i
))))
603 this_result
= find_single_use_1 (dest
, &XEXP (x
, i
));
606 result
= this_result
;
607 else if (this_result
)
608 /* Duplicate usage. */
611 else if (fmt
[i
] == 'E')
615 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
617 if (XVECEXP (x
, i
, j
) == dest
619 && REG_P (XVECEXP (x
, i
, j
))
620 && REGNO (XVECEXP (x
, i
, j
)) == REGNO (dest
)))
623 this_result
= find_single_use_1 (dest
, &XVECEXP (x
, i
, j
));
626 result
= this_result
;
627 else if (this_result
)
637 /* See if DEST, produced in INSN, is used only a single time in the
638 sequel. If so, return a pointer to the innermost rtx expression in which
641 If PLOC is nonzero, *PLOC is set to the insn containing the single use.
643 If DEST is cc0_rtx, we look only at the next insn. In that case, we don't
644 care about REG_DEAD notes or LOG_LINKS.
646 Otherwise, we find the single use by finding an insn that has a
647 LOG_LINKS pointing at INSN and has a REG_DEAD note for DEST. If DEST is
648 only referenced once in that insn, we know that it must be the first
649 and last insn referencing DEST. */
652 find_single_use (rtx dest
, rtx_insn
*insn
, rtx_insn
**ploc
)
657 struct insn_link
*link
;
661 next
= NEXT_INSN (insn
);
663 || (!NONJUMP_INSN_P (next
) && !JUMP_P (next
)))
666 result
= find_single_use_1 (dest
, &PATTERN (next
));
675 bb
= BLOCK_FOR_INSN (insn
);
676 for (next
= NEXT_INSN (insn
);
677 next
&& BLOCK_FOR_INSN (next
) == bb
;
678 next
= NEXT_INSN (next
))
679 if (INSN_P (next
) && dead_or_set_p (next
, dest
))
681 FOR_EACH_LOG_LINK (link
, next
)
682 if (link
->insn
== insn
&& link
->regno
== REGNO (dest
))
687 result
= find_single_use_1 (dest
, &PATTERN (next
));
697 /* Substitute NEWVAL, an rtx expression, into INTO, a place in some
698 insn. The substitution can be undone by undo_all. If INTO is already
699 set to NEWVAL, do not record this change. Because computing NEWVAL might
700 also call SUBST, we have to compute it before we put anything into
704 do_SUBST (rtx
*into
, rtx newval
)
709 if (oldval
== newval
)
712 /* We'd like to catch as many invalid transformations here as
713 possible. Unfortunately, there are way too many mode changes
714 that are perfectly valid, so we'd waste too much effort for
715 little gain doing the checks here. Focus on catching invalid
716 transformations involving integer constants. */
717 if (GET_MODE_CLASS (GET_MODE (oldval
)) == MODE_INT
718 && CONST_INT_P (newval
))
720 /* Sanity check that we're replacing oldval with a CONST_INT
721 that is a valid sign-extension for the original mode. */
722 gcc_assert (INTVAL (newval
)
723 == trunc_int_for_mode (INTVAL (newval
), GET_MODE (oldval
)));
725 /* Replacing the operand of a SUBREG or a ZERO_EXTEND with a
726 CONST_INT is not valid, because after the replacement, the
727 original mode would be gone. Unfortunately, we can't tell
728 when do_SUBST is called to replace the operand thereof, so we
729 perform this test on oldval instead, checking whether an
730 invalid replacement took place before we got here. */
731 gcc_assert (!(GET_CODE (oldval
) == SUBREG
732 && CONST_INT_P (SUBREG_REG (oldval
))));
733 gcc_assert (!(GET_CODE (oldval
) == ZERO_EXTEND
734 && CONST_INT_P (XEXP (oldval
, 0))));
738 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
740 buf
= XNEW (struct undo
);
742 buf
->kind
= UNDO_RTX
;
744 buf
->old_contents
.r
= oldval
;
747 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
750 #define SUBST(INTO, NEWVAL) do_SUBST (&(INTO), (NEWVAL))
752 /* Similar to SUBST, but NEWVAL is an int expression. Note that substitution
753 for the value of a HOST_WIDE_INT value (including CONST_INT) is
757 do_SUBST_INT (int *into
, int newval
)
762 if (oldval
== newval
)
766 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
768 buf
= XNEW (struct undo
);
770 buf
->kind
= UNDO_INT
;
772 buf
->old_contents
.i
= oldval
;
775 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
778 #define SUBST_INT(INTO, NEWVAL) do_SUBST_INT (&(INTO), (NEWVAL))
780 /* Similar to SUBST, but just substitute the mode. This is used when
781 changing the mode of a pseudo-register, so that any other
782 references to the entry in the regno_reg_rtx array will change as
786 do_SUBST_MODE (rtx
*into
, machine_mode newval
)
789 machine_mode oldval
= GET_MODE (*into
);
791 if (oldval
== newval
)
795 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
797 buf
= XNEW (struct undo
);
799 buf
->kind
= UNDO_MODE
;
801 buf
->old_contents
.m
= oldval
;
802 adjust_reg_mode (*into
, newval
);
804 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
807 #define SUBST_MODE(INTO, NEWVAL) do_SUBST_MODE (&(INTO), (NEWVAL))
809 /* Similar to SUBST, but NEWVAL is a LOG_LINKS expression. */
812 do_SUBST_LINK (struct insn_link
**into
, struct insn_link
*newval
)
815 struct insn_link
* oldval
= *into
;
817 if (oldval
== newval
)
821 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
823 buf
= XNEW (struct undo
);
825 buf
->kind
= UNDO_LINKS
;
827 buf
->old_contents
.l
= oldval
;
830 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
833 #define SUBST_LINK(oldval, newval) do_SUBST_LINK (&oldval, newval)
835 /* Subroutine of try_combine. Determine whether the replacement patterns
836 NEWPAT, NEWI2PAT and NEWOTHERPAT are cheaper according to insn_rtx_cost
837 than the original sequence I0, I1, I2, I3 and undobuf.other_insn. Note
838 that I0, I1 and/or NEWI2PAT may be NULL_RTX. Similarly, NEWOTHERPAT and
839 undobuf.other_insn may also both be NULL_RTX. Return false if the cost
840 of all the instructions can be estimated and the replacements are more
841 expensive than the original sequence. */
844 combine_validate_cost (rtx_insn
*i0
, rtx_insn
*i1
, rtx_insn
*i2
, rtx_insn
*i3
,
845 rtx newpat
, rtx newi2pat
, rtx newotherpat
)
847 int i0_cost
, i1_cost
, i2_cost
, i3_cost
;
848 int new_i2_cost
, new_i3_cost
;
849 int old_cost
, new_cost
;
851 /* Lookup the original insn_rtx_costs. */
852 i2_cost
= INSN_COST (i2
);
853 i3_cost
= INSN_COST (i3
);
857 i1_cost
= INSN_COST (i1
);
860 i0_cost
= INSN_COST (i0
);
861 old_cost
= (i0_cost
> 0 && i1_cost
> 0 && i2_cost
> 0 && i3_cost
> 0
862 ? i0_cost
+ i1_cost
+ i2_cost
+ i3_cost
: 0);
866 old_cost
= (i1_cost
> 0 && i2_cost
> 0 && i3_cost
> 0
867 ? i1_cost
+ i2_cost
+ i3_cost
: 0);
873 old_cost
= (i2_cost
> 0 && i3_cost
> 0) ? i2_cost
+ i3_cost
: 0;
874 i1_cost
= i0_cost
= 0;
877 /* If we have split a PARALLEL I2 to I1,I2, we have counted its cost twice;
879 if (old_cost
&& i1
&& INSN_UID (i1
) == INSN_UID (i2
))
883 /* Calculate the replacement insn_rtx_costs. */
884 new_i3_cost
= insn_rtx_cost (newpat
, optimize_this_for_speed_p
);
887 new_i2_cost
= insn_rtx_cost (newi2pat
, optimize_this_for_speed_p
);
888 new_cost
= (new_i2_cost
> 0 && new_i3_cost
> 0)
889 ? new_i2_cost
+ new_i3_cost
: 0;
893 new_cost
= new_i3_cost
;
897 if (undobuf
.other_insn
)
899 int old_other_cost
, new_other_cost
;
901 old_other_cost
= INSN_COST (undobuf
.other_insn
);
902 new_other_cost
= insn_rtx_cost (newotherpat
, optimize_this_for_speed_p
);
903 if (old_other_cost
> 0 && new_other_cost
> 0)
905 old_cost
+= old_other_cost
;
906 new_cost
+= new_other_cost
;
912 /* Disallow this combination if both new_cost and old_cost are greater than
913 zero, and new_cost is greater than old cost. */
914 int reject
= old_cost
> 0 && new_cost
> old_cost
;
918 fprintf (dump_file
, "%s combination of insns ",
919 reject
? "rejecting" : "allowing");
921 fprintf (dump_file
, "%d, ", INSN_UID (i0
));
922 if (i1
&& INSN_UID (i1
) != INSN_UID (i2
))
923 fprintf (dump_file
, "%d, ", INSN_UID (i1
));
924 fprintf (dump_file
, "%d and %d\n", INSN_UID (i2
), INSN_UID (i3
));
926 fprintf (dump_file
, "original costs ");
928 fprintf (dump_file
, "%d + ", i0_cost
);
929 if (i1
&& INSN_UID (i1
) != INSN_UID (i2
))
930 fprintf (dump_file
, "%d + ", i1_cost
);
931 fprintf (dump_file
, "%d + %d = %d\n", i2_cost
, i3_cost
, old_cost
);
934 fprintf (dump_file
, "replacement costs %d + %d = %d\n",
935 new_i2_cost
, new_i3_cost
, new_cost
);
937 fprintf (dump_file
, "replacement cost %d\n", new_cost
);
943 /* Update the uid_insn_cost array with the replacement costs. */
944 INSN_COST (i2
) = new_i2_cost
;
945 INSN_COST (i3
) = new_i3_cost
;
957 /* Delete any insns that copy a register to itself. */
960 delete_noop_moves (void)
962 rtx_insn
*insn
, *next
;
965 FOR_EACH_BB_FN (bb
, cfun
)
967 for (insn
= BB_HEAD (bb
); insn
!= NEXT_INSN (BB_END (bb
)); insn
= next
)
969 next
= NEXT_INSN (insn
);
970 if (INSN_P (insn
) && noop_move_p (insn
))
973 fprintf (dump_file
, "deleting noop move %d\n", INSN_UID (insn
));
975 delete_insn_and_edges (insn
);
982 /* Return false if we do not want to (or cannot) combine DEF. */
984 can_combine_def_p (df_ref def
)
986 /* Do not consider if it is pre/post modification in MEM. */
987 if (DF_REF_FLAGS (def
) & DF_REF_PRE_POST_MODIFY
)
990 unsigned int regno
= DF_REF_REGNO (def
);
992 /* Do not combine frame pointer adjustments. */
993 if ((regno
== FRAME_POINTER_REGNUM
994 && (!reload_completed
|| frame_pointer_needed
))
995 || (!HARD_FRAME_POINTER_IS_FRAME_POINTER
996 && regno
== HARD_FRAME_POINTER_REGNUM
997 && (!reload_completed
|| frame_pointer_needed
))
998 || (FRAME_POINTER_REGNUM
!= ARG_POINTER_REGNUM
999 && regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
]))
1005 /* Return false if we do not want to (or cannot) combine USE. */
1007 can_combine_use_p (df_ref use
)
1009 /* Do not consider the usage of the stack pointer by function call. */
1010 if (DF_REF_FLAGS (use
) & DF_REF_CALL_STACK_USAGE
)
1016 /* Fill in log links field for all insns. */
1019 create_log_links (void)
1022 rtx_insn
**next_use
;
1026 next_use
= XCNEWVEC (rtx_insn
*, max_reg_num ());
1028 /* Pass through each block from the end, recording the uses of each
1029 register and establishing log links when def is encountered.
1030 Note that we do not clear next_use array in order to save time,
1031 so we have to test whether the use is in the same basic block as def.
1033 There are a few cases below when we do not consider the definition or
1034 usage -- these are taken from original flow.c did. Don't ask me why it is
1035 done this way; I don't know and if it works, I don't want to know. */
1037 FOR_EACH_BB_FN (bb
, cfun
)
1039 FOR_BB_INSNS_REVERSE (bb
, insn
)
1041 if (!NONDEBUG_INSN_P (insn
))
1044 /* Log links are created only once. */
1045 gcc_assert (!LOG_LINKS (insn
));
1047 FOR_EACH_INSN_DEF (def
, insn
)
1049 unsigned int regno
= DF_REF_REGNO (def
);
1052 if (!next_use
[regno
])
1055 if (!can_combine_def_p (def
))
1058 use_insn
= next_use
[regno
];
1059 next_use
[regno
] = NULL
;
1061 if (BLOCK_FOR_INSN (use_insn
) != bb
)
1066 We don't build a LOG_LINK for hard registers contained
1067 in ASM_OPERANDs. If these registers get replaced,
1068 we might wind up changing the semantics of the insn,
1069 even if reload can make what appear to be valid
1070 assignments later. */
1071 if (regno
< FIRST_PSEUDO_REGISTER
1072 && asm_noperands (PATTERN (use_insn
)) >= 0)
1075 /* Don't add duplicate links between instructions. */
1076 struct insn_link
*links
;
1077 FOR_EACH_LOG_LINK (links
, use_insn
)
1078 if (insn
== links
->insn
&& regno
== links
->regno
)
1082 LOG_LINKS (use_insn
)
1083 = alloc_insn_link (insn
, regno
, LOG_LINKS (use_insn
));
1086 FOR_EACH_INSN_USE (use
, insn
)
1087 if (can_combine_use_p (use
))
1088 next_use
[DF_REF_REGNO (use
)] = insn
;
1095 /* Walk the LOG_LINKS of insn B to see if we find a reference to A. Return
1096 true if we found a LOG_LINK that proves that A feeds B. This only works
1097 if there are no instructions between A and B which could have a link
1098 depending on A, since in that case we would not record a link for B.
1099 We also check the implicit dependency created by a cc0 setter/user
1103 insn_a_feeds_b (rtx_insn
*a
, rtx_insn
*b
)
1105 struct insn_link
*links
;
1106 FOR_EACH_LOG_LINK (links
, b
)
1107 if (links
->insn
== a
)
1109 if (HAVE_cc0
&& sets_cc0_p (a
))
1114 /* Main entry point for combiner. F is the first insn of the function.
1115 NREGS is the first unused pseudo-reg number.
1117 Return nonzero if the combiner has turned an indirect jump
1118 instruction into a direct jump. */
1120 combine_instructions (rtx_insn
*f
, unsigned int nregs
)
1122 rtx_insn
*insn
, *next
;
1124 struct insn_link
*links
, *nextlinks
;
1126 basic_block last_bb
;
1128 int new_direct_jump_p
= 0;
1130 for (first
= f
; first
&& !INSN_P (first
); )
1131 first
= NEXT_INSN (first
);
1135 combine_attempts
= 0;
1138 combine_successes
= 0;
1140 rtl_hooks
= combine_rtl_hooks
;
1142 reg_stat
.safe_grow_cleared (nregs
);
1144 init_recog_no_volatile ();
1146 /* Allocate array for insn info. */
1147 max_uid_known
= get_max_uid ();
1148 uid_log_links
= XCNEWVEC (struct insn_link
*, max_uid_known
+ 1);
1149 uid_insn_cost
= XCNEWVEC (int, max_uid_known
+ 1);
1150 gcc_obstack_init (&insn_link_obstack
);
1152 nonzero_bits_mode
= mode_for_size (HOST_BITS_PER_WIDE_INT
, MODE_INT
, 0);
1154 /* Don't use reg_stat[].nonzero_bits when computing it. This can cause
1155 problems when, for example, we have j <<= 1 in a loop. */
1157 nonzero_sign_valid
= 0;
1158 label_tick
= label_tick_ebb_start
= 1;
1160 /* Scan all SETs and see if we can deduce anything about what
1161 bits are known to be zero for some registers and how many copies
1162 of the sign bit are known to exist for those registers.
1164 Also set any known values so that we can use it while searching
1165 for what bits are known to be set. */
1167 setup_incoming_promotions (first
);
1168 /* Allow the entry block and the first block to fall into the same EBB.
1169 Conceptually the incoming promotions are assigned to the entry block. */
1170 last_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
1172 create_log_links ();
1173 FOR_EACH_BB_FN (this_basic_block
, cfun
)
1175 optimize_this_for_speed_p
= optimize_bb_for_speed_p (this_basic_block
);
1180 if (!single_pred_p (this_basic_block
)
1181 || single_pred (this_basic_block
) != last_bb
)
1182 label_tick_ebb_start
= label_tick
;
1183 last_bb
= this_basic_block
;
1185 FOR_BB_INSNS (this_basic_block
, insn
)
1186 if (INSN_P (insn
) && BLOCK_FOR_INSN (insn
))
1190 subst_low_luid
= DF_INSN_LUID (insn
);
1193 note_stores (PATTERN (insn
), set_nonzero_bits_and_sign_copies
,
1195 record_dead_and_set_regs (insn
);
1198 for (links
= REG_NOTES (insn
); links
; links
= XEXP (links
, 1))
1199 if (REG_NOTE_KIND (links
) == REG_INC
)
1200 set_nonzero_bits_and_sign_copies (XEXP (links
, 0), NULL_RTX
,
1203 /* Record the current insn_rtx_cost of this instruction. */
1204 if (NONJUMP_INSN_P (insn
))
1205 INSN_COST (insn
) = insn_rtx_cost (PATTERN (insn
),
1206 optimize_this_for_speed_p
);
1208 fprintf (dump_file
, "insn_cost %d: %d\n",
1209 INSN_UID (insn
), INSN_COST (insn
));
1213 nonzero_sign_valid
= 1;
1215 /* Now scan all the insns in forward order. */
1216 label_tick
= label_tick_ebb_start
= 1;
1218 setup_incoming_promotions (first
);
1219 last_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
1220 int max_combine
= PARAM_VALUE (PARAM_MAX_COMBINE_INSNS
);
1222 FOR_EACH_BB_FN (this_basic_block
, cfun
)
1224 rtx_insn
*last_combined_insn
= NULL
;
1225 optimize_this_for_speed_p
= optimize_bb_for_speed_p (this_basic_block
);
1230 if (!single_pred_p (this_basic_block
)
1231 || single_pred (this_basic_block
) != last_bb
)
1232 label_tick_ebb_start
= label_tick
;
1233 last_bb
= this_basic_block
;
1235 rtl_profile_for_bb (this_basic_block
);
1236 for (insn
= BB_HEAD (this_basic_block
);
1237 insn
!= NEXT_INSN (BB_END (this_basic_block
));
1238 insn
= next
? next
: NEXT_INSN (insn
))
1241 if (!NONDEBUG_INSN_P (insn
))
1244 while (last_combined_insn
1245 && last_combined_insn
->deleted ())
1246 last_combined_insn
= PREV_INSN (last_combined_insn
);
1247 if (last_combined_insn
== NULL_RTX
1248 || BARRIER_P (last_combined_insn
)
1249 || BLOCK_FOR_INSN (last_combined_insn
) != this_basic_block
1250 || DF_INSN_LUID (last_combined_insn
) <= DF_INSN_LUID (insn
))
1251 last_combined_insn
= insn
;
1253 /* See if we know about function return values before this
1254 insn based upon SUBREG flags. */
1255 check_promoted_subreg (insn
, PATTERN (insn
));
1257 /* See if we can find hardregs and subreg of pseudos in
1258 narrower modes. This could help turning TRUNCATEs
1260 note_uses (&PATTERN (insn
), record_truncated_values
, NULL
);
1262 /* Try this insn with each insn it links back to. */
1264 FOR_EACH_LOG_LINK (links
, insn
)
1265 if ((next
= try_combine (insn
, links
->insn
, NULL
,
1266 NULL
, &new_direct_jump_p
,
1267 last_combined_insn
)) != 0)
1269 statistics_counter_event (cfun
, "two-insn combine", 1);
1273 /* Try each sequence of three linked insns ending with this one. */
1275 if (max_combine
>= 3)
1276 FOR_EACH_LOG_LINK (links
, insn
)
1278 rtx_insn
*link
= links
->insn
;
1280 /* If the linked insn has been replaced by a note, then there
1281 is no point in pursuing this chain any further. */
1285 FOR_EACH_LOG_LINK (nextlinks
, link
)
1286 if ((next
= try_combine (insn
, link
, nextlinks
->insn
,
1287 NULL
, &new_direct_jump_p
,
1288 last_combined_insn
)) != 0)
1290 statistics_counter_event (cfun
, "three-insn combine", 1);
1295 /* Try to combine a jump insn that uses CC0
1296 with a preceding insn that sets CC0, and maybe with its
1297 logical predecessor as well.
1298 This is how we make decrement-and-branch insns.
1299 We need this special code because data flow connections
1300 via CC0 do not get entered in LOG_LINKS. */
1304 && (prev
= prev_nonnote_insn (insn
)) != 0
1305 && NONJUMP_INSN_P (prev
)
1306 && sets_cc0_p (PATTERN (prev
)))
1308 if ((next
= try_combine (insn
, prev
, NULL
, NULL
,
1310 last_combined_insn
)) != 0)
1313 FOR_EACH_LOG_LINK (nextlinks
, prev
)
1314 if ((next
= try_combine (insn
, prev
, nextlinks
->insn
,
1315 NULL
, &new_direct_jump_p
,
1316 last_combined_insn
)) != 0)
1320 /* Do the same for an insn that explicitly references CC0. */
1321 if (HAVE_cc0
&& NONJUMP_INSN_P (insn
)
1322 && (prev
= prev_nonnote_insn (insn
)) != 0
1323 && NONJUMP_INSN_P (prev
)
1324 && sets_cc0_p (PATTERN (prev
))
1325 && GET_CODE (PATTERN (insn
)) == SET
1326 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (insn
))))
1328 if ((next
= try_combine (insn
, prev
, NULL
, NULL
,
1330 last_combined_insn
)) != 0)
1333 FOR_EACH_LOG_LINK (nextlinks
, prev
)
1334 if ((next
= try_combine (insn
, prev
, nextlinks
->insn
,
1335 NULL
, &new_direct_jump_p
,
1336 last_combined_insn
)) != 0)
1340 /* Finally, see if any of the insns that this insn links to
1341 explicitly references CC0. If so, try this insn, that insn,
1342 and its predecessor if it sets CC0. */
1345 FOR_EACH_LOG_LINK (links
, insn
)
1346 if (NONJUMP_INSN_P (links
->insn
)
1347 && GET_CODE (PATTERN (links
->insn
)) == SET
1348 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (links
->insn
)))
1349 && (prev
= prev_nonnote_insn (links
->insn
)) != 0
1350 && NONJUMP_INSN_P (prev
)
1351 && sets_cc0_p (PATTERN (prev
))
1352 && (next
= try_combine (insn
, links
->insn
,
1353 prev
, NULL
, &new_direct_jump_p
,
1354 last_combined_insn
)) != 0)
1358 /* Try combining an insn with two different insns whose results it
1360 if (max_combine
>= 3)
1361 FOR_EACH_LOG_LINK (links
, insn
)
1362 for (nextlinks
= links
->next
; nextlinks
;
1363 nextlinks
= nextlinks
->next
)
1364 if ((next
= try_combine (insn
, links
->insn
,
1365 nextlinks
->insn
, NULL
,
1367 last_combined_insn
)) != 0)
1370 statistics_counter_event (cfun
, "three-insn combine", 1);
1374 /* Try four-instruction combinations. */
1375 if (max_combine
>= 4)
1376 FOR_EACH_LOG_LINK (links
, insn
)
1378 struct insn_link
*next1
;
1379 rtx_insn
*link
= links
->insn
;
1381 /* If the linked insn has been replaced by a note, then there
1382 is no point in pursuing this chain any further. */
1386 FOR_EACH_LOG_LINK (next1
, link
)
1388 rtx_insn
*link1
= next1
->insn
;
1391 /* I0 -> I1 -> I2 -> I3. */
1392 FOR_EACH_LOG_LINK (nextlinks
, link1
)
1393 if ((next
= try_combine (insn
, link
, link1
,
1396 last_combined_insn
)) != 0)
1398 statistics_counter_event (cfun
, "four-insn combine", 1);
1401 /* I0, I1 -> I2, I2 -> I3. */
1402 for (nextlinks
= next1
->next
; nextlinks
;
1403 nextlinks
= nextlinks
->next
)
1404 if ((next
= try_combine (insn
, link
, link1
,
1407 last_combined_insn
)) != 0)
1409 statistics_counter_event (cfun
, "four-insn combine", 1);
1414 for (next1
= links
->next
; next1
; next1
= next1
->next
)
1416 rtx_insn
*link1
= next1
->insn
;
1419 /* I0 -> I2; I1, I2 -> I3. */
1420 FOR_EACH_LOG_LINK (nextlinks
, link
)
1421 if ((next
= try_combine (insn
, link
, link1
,
1424 last_combined_insn
)) != 0)
1426 statistics_counter_event (cfun
, "four-insn combine", 1);
1429 /* I0 -> I1; I1, I2 -> I3. */
1430 FOR_EACH_LOG_LINK (nextlinks
, link1
)
1431 if ((next
= try_combine (insn
, link
, link1
,
1434 last_combined_insn
)) != 0)
1436 statistics_counter_event (cfun
, "four-insn combine", 1);
1442 /* Try this insn with each REG_EQUAL note it links back to. */
1443 FOR_EACH_LOG_LINK (links
, insn
)
1446 rtx_insn
*temp
= links
->insn
;
1447 if ((set
= single_set (temp
)) != 0
1448 && (note
= find_reg_equal_equiv_note (temp
)) != 0
1449 && (note
= XEXP (note
, 0), GET_CODE (note
)) != EXPR_LIST
1450 /* Avoid using a register that may already been marked
1451 dead by an earlier instruction. */
1452 && ! unmentioned_reg_p (note
, SET_SRC (set
))
1453 && (GET_MODE (note
) == VOIDmode
1454 ? SCALAR_INT_MODE_P (GET_MODE (SET_DEST (set
)))
1455 : (GET_MODE (SET_DEST (set
)) == GET_MODE (note
)
1456 && (GET_CODE (SET_DEST (set
)) != ZERO_EXTRACT
1457 || (GET_MODE (XEXP (SET_DEST (set
), 0))
1458 == GET_MODE (note
))))))
1460 /* Temporarily replace the set's source with the
1461 contents of the REG_EQUAL note. The insn will
1462 be deleted or recognized by try_combine. */
1463 rtx orig_src
= SET_SRC (set
);
1464 rtx orig_dest
= SET_DEST (set
);
1465 if (GET_CODE (SET_DEST (set
)) == ZERO_EXTRACT
)
1466 SET_DEST (set
) = XEXP (SET_DEST (set
), 0);
1467 SET_SRC (set
) = note
;
1469 i2mod_old_rhs
= copy_rtx (orig_src
);
1470 i2mod_new_rhs
= copy_rtx (note
);
1471 next
= try_combine (insn
, i2mod
, NULL
, NULL
,
1473 last_combined_insn
);
1477 statistics_counter_event (cfun
, "insn-with-note combine", 1);
1480 SET_SRC (set
) = orig_src
;
1481 SET_DEST (set
) = orig_dest
;
1486 record_dead_and_set_regs (insn
);
1493 default_rtl_profile ();
1495 new_direct_jump_p
|= purge_all_dead_edges ();
1496 delete_noop_moves ();
1499 obstack_free (&insn_link_obstack
, NULL
);
1500 free (uid_log_links
);
1501 free (uid_insn_cost
);
1502 reg_stat
.release ();
1505 struct undo
*undo
, *next
;
1506 for (undo
= undobuf
.frees
; undo
; undo
= next
)
1514 total_attempts
+= combine_attempts
;
1515 total_merges
+= combine_merges
;
1516 total_extras
+= combine_extras
;
1517 total_successes
+= combine_successes
;
1519 nonzero_sign_valid
= 0;
1520 rtl_hooks
= general_rtl_hooks
;
1522 /* Make recognizer allow volatile MEMs again. */
1525 return new_direct_jump_p
;
1528 /* Wipe the last_xxx fields of reg_stat in preparation for another pass. */
1531 init_reg_last (void)
1536 FOR_EACH_VEC_ELT (reg_stat
, i
, p
)
1537 memset (p
, 0, offsetof (reg_stat_type
, sign_bit_copies
));
1540 /* Set up any promoted values for incoming argument registers. */
1543 setup_incoming_promotions (rtx_insn
*first
)
1546 bool strictly_local
= false;
1548 for (arg
= DECL_ARGUMENTS (current_function_decl
); arg
;
1549 arg
= DECL_CHAIN (arg
))
1551 rtx x
, reg
= DECL_INCOMING_RTL (arg
);
1553 machine_mode mode1
, mode2
, mode3
, mode4
;
1555 /* Only continue if the incoming argument is in a register. */
1559 /* Determine, if possible, whether all call sites of the current
1560 function lie within the current compilation unit. (This does
1561 take into account the exporting of a function via taking its
1562 address, and so forth.) */
1563 strictly_local
= cgraph_node::local_info (current_function_decl
)->local
;
1565 /* The mode and signedness of the argument before any promotions happen
1566 (equal to the mode of the pseudo holding it at that stage). */
1567 mode1
= TYPE_MODE (TREE_TYPE (arg
));
1568 uns1
= TYPE_UNSIGNED (TREE_TYPE (arg
));
1570 /* The mode and signedness of the argument after any source language and
1571 TARGET_PROMOTE_PROTOTYPES-driven promotions. */
1572 mode2
= TYPE_MODE (DECL_ARG_TYPE (arg
));
1573 uns3
= TYPE_UNSIGNED (DECL_ARG_TYPE (arg
));
1575 /* The mode and signedness of the argument as it is actually passed,
1576 see assign_parm_setup_reg in function.c. */
1577 mode3
= promote_function_mode (TREE_TYPE (arg
), mode1
, &uns3
,
1578 TREE_TYPE (cfun
->decl
), 0);
1580 /* The mode of the register in which the argument is being passed. */
1581 mode4
= GET_MODE (reg
);
1583 /* Eliminate sign extensions in the callee when:
1584 (a) A mode promotion has occurred; */
1587 /* (b) The mode of the register is the same as the mode of
1588 the argument as it is passed; */
1591 /* (c) There's no language level extension; */
1594 /* (c.1) All callers are from the current compilation unit. If that's
1595 the case we don't have to rely on an ABI, we only have to know
1596 what we're generating right now, and we know that we will do the
1597 mode1 to mode2 promotion with the given sign. */
1598 else if (!strictly_local
)
1600 /* (c.2) The combination of the two promotions is useful. This is
1601 true when the signs match, or if the first promotion is unsigned.
1602 In the later case, (sign_extend (zero_extend x)) is the same as
1603 (zero_extend (zero_extend x)), so make sure to force UNS3 true. */
1609 /* Record that the value was promoted from mode1 to mode3,
1610 so that any sign extension at the head of the current
1611 function may be eliminated. */
1612 x
= gen_rtx_CLOBBER (mode1
, const0_rtx
);
1613 x
= gen_rtx_fmt_e ((uns3
? ZERO_EXTEND
: SIGN_EXTEND
), mode3
, x
);
1614 record_value_for_reg (reg
, first
, x
);
1618 /* If MODE has a precision lower than PREC and SRC is a non-negative constant
1619 that would appear negative in MODE, sign-extend SRC for use in nonzero_bits
1620 because some machines (maybe most) will actually do the sign-extension and
1621 this is the conservative approach.
1623 ??? For 2.5, try to tighten up the MD files in this regard instead of this
1627 sign_extend_short_imm (rtx src
, machine_mode mode
, unsigned int prec
)
1629 if (GET_MODE_PRECISION (mode
) < prec
1630 && CONST_INT_P (src
)
1632 && val_signbit_known_set_p (mode
, INTVAL (src
)))
1633 src
= GEN_INT (INTVAL (src
) | ~GET_MODE_MASK (mode
));
1638 /* Update RSP for pseudo-register X from INSN's REG_EQUAL note (if one exists)
1642 update_rsp_from_reg_equal (reg_stat_type
*rsp
, rtx_insn
*insn
, const_rtx set
,
1645 rtx reg_equal_note
= insn
? find_reg_equal_equiv_note (insn
) : NULL_RTX
;
1646 unsigned HOST_WIDE_INT bits
= 0;
1647 rtx reg_equal
= NULL
, src
= SET_SRC (set
);
1648 unsigned int num
= 0;
1651 reg_equal
= XEXP (reg_equal_note
, 0);
1653 if (SHORT_IMMEDIATES_SIGN_EXTEND
)
1655 src
= sign_extend_short_imm (src
, GET_MODE (x
), BITS_PER_WORD
);
1657 reg_equal
= sign_extend_short_imm (reg_equal
, GET_MODE (x
), BITS_PER_WORD
);
1660 /* Don't call nonzero_bits if it cannot change anything. */
1661 if (rsp
->nonzero_bits
!= HOST_WIDE_INT_M1U
)
1663 bits
= nonzero_bits (src
, nonzero_bits_mode
);
1664 if (reg_equal
&& bits
)
1665 bits
&= nonzero_bits (reg_equal
, nonzero_bits_mode
);
1666 rsp
->nonzero_bits
|= bits
;
1669 /* Don't call num_sign_bit_copies if it cannot change anything. */
1670 if (rsp
->sign_bit_copies
!= 1)
1672 num
= num_sign_bit_copies (SET_SRC (set
), GET_MODE (x
));
1673 if (reg_equal
&& num
!= GET_MODE_PRECISION (GET_MODE (x
)))
1675 unsigned int numeq
= num_sign_bit_copies (reg_equal
, GET_MODE (x
));
1676 if (num
== 0 || numeq
> num
)
1679 if (rsp
->sign_bit_copies
== 0 || num
< rsp
->sign_bit_copies
)
1680 rsp
->sign_bit_copies
= num
;
1684 /* Called via note_stores. If X is a pseudo that is narrower than
1685 HOST_BITS_PER_WIDE_INT and is being set, record what bits are known zero.
1687 If we are setting only a portion of X and we can't figure out what
1688 portion, assume all bits will be used since we don't know what will
1691 Similarly, set how many bits of X are known to be copies of the sign bit
1692 at all locations in the function. This is the smallest number implied
1696 set_nonzero_bits_and_sign_copies (rtx x
, const_rtx set
, void *data
)
1698 rtx_insn
*insn
= (rtx_insn
*) data
;
1701 && REGNO (x
) >= FIRST_PSEUDO_REGISTER
1702 /* If this register is undefined at the start of the file, we can't
1703 say what its contents were. */
1704 && ! REGNO_REG_SET_P
1705 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
), REGNO (x
))
1706 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
)))
1708 reg_stat_type
*rsp
= ®_stat
[REGNO (x
)];
1710 if (set
== 0 || GET_CODE (set
) == CLOBBER
)
1712 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1713 rsp
->sign_bit_copies
= 1;
1717 /* If this register is being initialized using itself, and the
1718 register is uninitialized in this basic block, and there are
1719 no LOG_LINKS which set the register, then part of the
1720 register is uninitialized. In that case we can't assume
1721 anything about the number of nonzero bits.
1723 ??? We could do better if we checked this in
1724 reg_{nonzero_bits,num_sign_bit_copies}_for_combine. Then we
1725 could avoid making assumptions about the insn which initially
1726 sets the register, while still using the information in other
1727 insns. We would have to be careful to check every insn
1728 involved in the combination. */
1731 && reg_referenced_p (x
, PATTERN (insn
))
1732 && !REGNO_REG_SET_P (DF_LR_IN (BLOCK_FOR_INSN (insn
)),
1735 struct insn_link
*link
;
1737 FOR_EACH_LOG_LINK (link
, insn
)
1738 if (dead_or_set_p (link
->insn
, x
))
1742 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1743 rsp
->sign_bit_copies
= 1;
1748 /* If this is a complex assignment, see if we can convert it into a
1749 simple assignment. */
1750 set
= expand_field_assignment (set
);
1752 /* If this is a simple assignment, or we have a paradoxical SUBREG,
1753 set what we know about X. */
1755 if (SET_DEST (set
) == x
1756 || (paradoxical_subreg_p (SET_DEST (set
))
1757 && SUBREG_REG (SET_DEST (set
)) == x
))
1758 update_rsp_from_reg_equal (rsp
, insn
, set
, x
);
1761 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1762 rsp
->sign_bit_copies
= 1;
1767 /* See if INSN can be combined into I3. PRED, PRED2, SUCC and SUCC2 are
1768 optionally insns that were previously combined into I3 or that will be
1769 combined into the merger of INSN and I3. The order is PRED, PRED2,
1770 INSN, SUCC, SUCC2, I3.
1772 Return 0 if the combination is not allowed for any reason.
1774 If the combination is allowed, *PDEST will be set to the single
1775 destination of INSN and *PSRC to the single source, and this function
1779 can_combine_p (rtx_insn
*insn
, rtx_insn
*i3
, rtx_insn
*pred ATTRIBUTE_UNUSED
,
1780 rtx_insn
*pred2 ATTRIBUTE_UNUSED
, rtx_insn
*succ
, rtx_insn
*succ2
,
1781 rtx
*pdest
, rtx
*psrc
)
1788 bool all_adjacent
= true;
1789 int (*is_volatile_p
) (const_rtx
);
1795 if (next_active_insn (succ2
) != i3
)
1796 all_adjacent
= false;
1797 if (next_active_insn (succ
) != succ2
)
1798 all_adjacent
= false;
1800 else if (next_active_insn (succ
) != i3
)
1801 all_adjacent
= false;
1802 if (next_active_insn (insn
) != succ
)
1803 all_adjacent
= false;
1805 else if (next_active_insn (insn
) != i3
)
1806 all_adjacent
= false;
1808 /* Can combine only if previous insn is a SET of a REG, a SUBREG or CC0.
1809 or a PARALLEL consisting of such a SET and CLOBBERs.
1811 If INSN has CLOBBER parallel parts, ignore them for our processing.
1812 By definition, these happen during the execution of the insn. When it
1813 is merged with another insn, all bets are off. If they are, in fact,
1814 needed and aren't also supplied in I3, they may be added by
1815 recog_for_combine. Otherwise, it won't match.
1817 We can also ignore a SET whose SET_DEST is mentioned in a REG_UNUSED
1820 Get the source and destination of INSN. If more than one, can't
1823 if (GET_CODE (PATTERN (insn
)) == SET
)
1824 set
= PATTERN (insn
);
1825 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
1826 && GET_CODE (XVECEXP (PATTERN (insn
), 0, 0)) == SET
)
1828 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
1830 rtx elt
= XVECEXP (PATTERN (insn
), 0, i
);
1832 switch (GET_CODE (elt
))
1834 /* This is important to combine floating point insns
1835 for the SH4 port. */
1837 /* Combining an isolated USE doesn't make sense.
1838 We depend here on combinable_i3pat to reject them. */
1839 /* The code below this loop only verifies that the inputs of
1840 the SET in INSN do not change. We call reg_set_between_p
1841 to verify that the REG in the USE does not change between
1843 If the USE in INSN was for a pseudo register, the matching
1844 insn pattern will likely match any register; combining this
1845 with any other USE would only be safe if we knew that the
1846 used registers have identical values, or if there was
1847 something to tell them apart, e.g. different modes. For
1848 now, we forgo such complicated tests and simply disallow
1849 combining of USES of pseudo registers with any other USE. */
1850 if (REG_P (XEXP (elt
, 0))
1851 && GET_CODE (PATTERN (i3
)) == PARALLEL
)
1853 rtx i3pat
= PATTERN (i3
);
1854 int i
= XVECLEN (i3pat
, 0) - 1;
1855 unsigned int regno
= REGNO (XEXP (elt
, 0));
1859 rtx i3elt
= XVECEXP (i3pat
, 0, i
);
1861 if (GET_CODE (i3elt
) == USE
1862 && REG_P (XEXP (i3elt
, 0))
1863 && (REGNO (XEXP (i3elt
, 0)) == regno
1864 ? reg_set_between_p (XEXP (elt
, 0),
1865 PREV_INSN (insn
), i3
)
1866 : regno
>= FIRST_PSEUDO_REGISTER
))
1873 /* We can ignore CLOBBERs. */
1878 /* Ignore SETs whose result isn't used but not those that
1879 have side-effects. */
1880 if (find_reg_note (insn
, REG_UNUSED
, SET_DEST (elt
))
1881 && insn_nothrow_p (insn
)
1882 && !side_effects_p (elt
))
1885 /* If we have already found a SET, this is a second one and
1886 so we cannot combine with this insn. */
1894 /* Anything else means we can't combine. */
1900 /* If SET_SRC is an ASM_OPERANDS we can't throw away these CLOBBERs,
1901 so don't do anything with it. */
1902 || GET_CODE (SET_SRC (set
)) == ASM_OPERANDS
)
1911 /* The simplification in expand_field_assignment may call back to
1912 get_last_value, so set safe guard here. */
1913 subst_low_luid
= DF_INSN_LUID (insn
);
1915 set
= expand_field_assignment (set
);
1916 src
= SET_SRC (set
), dest
= SET_DEST (set
);
1918 /* Do not eliminate user-specified register if it is in an
1919 asm input because we may break the register asm usage defined
1920 in GCC manual if allow to do so.
1921 Be aware that this may cover more cases than we expect but this
1922 should be harmless. */
1923 if (REG_P (dest
) && REG_USERVAR_P (dest
) && HARD_REGISTER_P (dest
)
1924 && extract_asm_operands (PATTERN (i3
)))
1927 /* Don't eliminate a store in the stack pointer. */
1928 if (dest
== stack_pointer_rtx
1929 /* Don't combine with an insn that sets a register to itself if it has
1930 a REG_EQUAL note. This may be part of a LIBCALL sequence. */
1931 || (rtx_equal_p (src
, dest
) && find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1932 /* Can't merge an ASM_OPERANDS. */
1933 || GET_CODE (src
) == ASM_OPERANDS
1934 /* Can't merge a function call. */
1935 || GET_CODE (src
) == CALL
1936 /* Don't eliminate a function call argument. */
1938 && (find_reg_fusage (i3
, USE
, dest
)
1940 && REGNO (dest
) < FIRST_PSEUDO_REGISTER
1941 && global_regs
[REGNO (dest
)])))
1942 /* Don't substitute into an incremented register. */
1943 || FIND_REG_INC_NOTE (i3
, dest
)
1944 || (succ
&& FIND_REG_INC_NOTE (succ
, dest
))
1945 || (succ2
&& FIND_REG_INC_NOTE (succ2
, dest
))
1946 /* Don't substitute into a non-local goto, this confuses CFG. */
1947 || (JUMP_P (i3
) && find_reg_note (i3
, REG_NON_LOCAL_GOTO
, NULL_RTX
))
1948 /* Make sure that DEST is not used after SUCC but before I3. */
1951 && (reg_used_between_p (dest
, succ2
, i3
)
1952 || reg_used_between_p (dest
, succ
, succ2
)))
1953 || (!succ2
&& succ
&& reg_used_between_p (dest
, succ
, i3
))))
1954 /* Make sure that the value that is to be substituted for the register
1955 does not use any registers whose values alter in between. However,
1956 If the insns are adjacent, a use can't cross a set even though we
1957 think it might (this can happen for a sequence of insns each setting
1958 the same destination; last_set of that register might point to
1959 a NOTE). If INSN has a REG_EQUIV note, the register is always
1960 equivalent to the memory so the substitution is valid even if there
1961 are intervening stores. Also, don't move a volatile asm or
1962 UNSPEC_VOLATILE across any other insns. */
1965 || ! find_reg_note (insn
, REG_EQUIV
, src
))
1966 && use_crosses_set_p (src
, DF_INSN_LUID (insn
)))
1967 || (GET_CODE (src
) == ASM_OPERANDS
&& MEM_VOLATILE_P (src
))
1968 || GET_CODE (src
) == UNSPEC_VOLATILE
))
1969 /* Don't combine across a CALL_INSN, because that would possibly
1970 change whether the life span of some REGs crosses calls or not,
1971 and it is a pain to update that information.
1972 Exception: if source is a constant, moving it later can't hurt.
1973 Accept that as a special case. */
1974 || (DF_INSN_LUID (insn
) < last_call_luid
&& ! CONSTANT_P (src
)))
1977 /* DEST must either be a REG or CC0. */
1980 /* If register alignment is being enforced for multi-word items in all
1981 cases except for parameters, it is possible to have a register copy
1982 insn referencing a hard register that is not allowed to contain the
1983 mode being copied and which would not be valid as an operand of most
1984 insns. Eliminate this problem by not combining with such an insn.
1986 Also, on some machines we don't want to extend the life of a hard
1990 && ((REGNO (dest
) < FIRST_PSEUDO_REGISTER
1991 && ! HARD_REGNO_MODE_OK (REGNO (dest
), GET_MODE (dest
)))
1992 /* Don't extend the life of a hard register unless it is
1993 user variable (if we have few registers) or it can't
1994 fit into the desired register (meaning something special
1996 Also avoid substituting a return register into I3, because
1997 reload can't handle a conflict with constraints of other
1999 || (REGNO (src
) < FIRST_PSEUDO_REGISTER
2000 && ! HARD_REGNO_MODE_OK (REGNO (src
), GET_MODE (src
)))))
2003 else if (GET_CODE (dest
) != CC0
)
2007 if (GET_CODE (PATTERN (i3
)) == PARALLEL
)
2008 for (i
= XVECLEN (PATTERN (i3
), 0) - 1; i
>= 0; i
--)
2009 if (GET_CODE (XVECEXP (PATTERN (i3
), 0, i
)) == CLOBBER
)
2011 rtx reg
= XEXP (XVECEXP (PATTERN (i3
), 0, i
), 0);
2013 /* If the clobber represents an earlyclobber operand, we must not
2014 substitute an expression containing the clobbered register.
2015 As we do not analyze the constraint strings here, we have to
2016 make the conservative assumption. However, if the register is
2017 a fixed hard reg, the clobber cannot represent any operand;
2018 we leave it up to the machine description to either accept or
2019 reject use-and-clobber patterns. */
2021 || REGNO (reg
) >= FIRST_PSEUDO_REGISTER
2022 || !fixed_regs
[REGNO (reg
)])
2023 if (reg_overlap_mentioned_p (reg
, src
))
2027 /* If INSN contains anything volatile, or is an `asm' (whether volatile
2028 or not), reject, unless nothing volatile comes between it and I3 */
2030 if (GET_CODE (src
) == ASM_OPERANDS
|| volatile_refs_p (src
))
2032 /* Make sure neither succ nor succ2 contains a volatile reference. */
2033 if (succ2
!= 0 && volatile_refs_p (PATTERN (succ2
)))
2035 if (succ
!= 0 && volatile_refs_p (PATTERN (succ
)))
2037 /* We'll check insns between INSN and I3 below. */
2040 /* If INSN is an asm, and DEST is a hard register, reject, since it has
2041 to be an explicit register variable, and was chosen for a reason. */
2043 if (GET_CODE (src
) == ASM_OPERANDS
2044 && REG_P (dest
) && REGNO (dest
) < FIRST_PSEUDO_REGISTER
)
2047 /* If INSN contains volatile references (specifically volatile MEMs),
2048 we cannot combine across any other volatile references.
2049 Even if INSN doesn't contain volatile references, any intervening
2050 volatile insn might affect machine state. */
2052 is_volatile_p
= volatile_refs_p (PATTERN (insn
))
2056 for (p
= NEXT_INSN (insn
); p
!= i3
; p
= NEXT_INSN (p
))
2057 if (INSN_P (p
) && p
!= succ
&& p
!= succ2
&& is_volatile_p (PATTERN (p
)))
2060 /* If INSN contains an autoincrement or autodecrement, make sure that
2061 register is not used between there and I3, and not already used in
2062 I3 either. Neither must it be used in PRED or SUCC, if they exist.
2063 Also insist that I3 not be a jump; if it were one
2064 and the incremented register were spilled, we would lose. */
2067 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2068 if (REG_NOTE_KIND (link
) == REG_INC
2070 || reg_used_between_p (XEXP (link
, 0), insn
, i3
)
2071 || (pred
!= NULL_RTX
2072 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (pred
)))
2073 || (pred2
!= NULL_RTX
2074 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (pred2
)))
2075 || (succ
!= NULL_RTX
2076 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (succ
)))
2077 || (succ2
!= NULL_RTX
2078 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (succ2
)))
2079 || reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i3
))))
2082 /* Don't combine an insn that follows a CC0-setting insn.
2083 An insn that uses CC0 must not be separated from the one that sets it.
2084 We do, however, allow I2 to follow a CC0-setting insn if that insn
2085 is passed as I1; in that case it will be deleted also.
2086 We also allow combining in this case if all the insns are adjacent
2087 because that would leave the two CC0 insns adjacent as well.
2088 It would be more logical to test whether CC0 occurs inside I1 or I2,
2089 but that would be much slower, and this ought to be equivalent. */
2093 p
= prev_nonnote_insn (insn
);
2094 if (p
&& p
!= pred
&& NONJUMP_INSN_P (p
) && sets_cc0_p (PATTERN (p
))
2099 /* If we get here, we have passed all the tests and the combination is
2108 /* LOC is the location within I3 that contains its pattern or the component
2109 of a PARALLEL of the pattern. We validate that it is valid for combining.
2111 One problem is if I3 modifies its output, as opposed to replacing it
2112 entirely, we can't allow the output to contain I2DEST, I1DEST or I0DEST as
2113 doing so would produce an insn that is not equivalent to the original insns.
2117 (set (reg:DI 101) (reg:DI 100))
2118 (set (subreg:SI (reg:DI 101) 0) <foo>)
2120 This is NOT equivalent to:
2122 (parallel [(set (subreg:SI (reg:DI 100) 0) <foo>)
2123 (set (reg:DI 101) (reg:DI 100))])
2125 Not only does this modify 100 (in which case it might still be valid
2126 if 100 were dead in I2), it sets 101 to the ORIGINAL value of 100.
2128 We can also run into a problem if I2 sets a register that I1
2129 uses and I1 gets directly substituted into I3 (not via I2). In that
2130 case, we would be getting the wrong value of I2DEST into I3, so we
2131 must reject the combination. This case occurs when I2 and I1 both
2132 feed into I3, rather than when I1 feeds into I2, which feeds into I3.
2133 If I1_NOT_IN_SRC is nonzero, it means that finding I1 in the source
2134 of a SET must prevent combination from occurring. The same situation
2135 can occur for I0, in which case I0_NOT_IN_SRC is set.
2137 Before doing the above check, we first try to expand a field assignment
2138 into a set of logical operations.
2140 If PI3_DEST_KILLED is nonzero, it is a pointer to a location in which
2141 we place a register that is both set and used within I3. If more than one
2142 such register is detected, we fail.
2144 Return 1 if the combination is valid, zero otherwise. */
2147 combinable_i3pat (rtx_insn
*i3
, rtx
*loc
, rtx i2dest
, rtx i1dest
, rtx i0dest
,
2148 int i1_not_in_src
, int i0_not_in_src
, rtx
*pi3dest_killed
)
2152 if (GET_CODE (x
) == SET
)
2155 rtx dest
= SET_DEST (set
);
2156 rtx src
= SET_SRC (set
);
2157 rtx inner_dest
= dest
;
2160 while (GET_CODE (inner_dest
) == STRICT_LOW_PART
2161 || GET_CODE (inner_dest
) == SUBREG
2162 || GET_CODE (inner_dest
) == ZERO_EXTRACT
)
2163 inner_dest
= XEXP (inner_dest
, 0);
2165 /* Check for the case where I3 modifies its output, as discussed
2166 above. We don't want to prevent pseudos from being combined
2167 into the address of a MEM, so only prevent the combination if
2168 i1 or i2 set the same MEM. */
2169 if ((inner_dest
!= dest
&&
2170 (!MEM_P (inner_dest
)
2171 || rtx_equal_p (i2dest
, inner_dest
)
2172 || (i1dest
&& rtx_equal_p (i1dest
, inner_dest
))
2173 || (i0dest
&& rtx_equal_p (i0dest
, inner_dest
)))
2174 && (reg_overlap_mentioned_p (i2dest
, inner_dest
)
2175 || (i1dest
&& reg_overlap_mentioned_p (i1dest
, inner_dest
))
2176 || (i0dest
&& reg_overlap_mentioned_p (i0dest
, inner_dest
))))
2178 /* This is the same test done in can_combine_p except we can't test
2179 all_adjacent; we don't have to, since this instruction will stay
2180 in place, thus we are not considering increasing the lifetime of
2183 Also, if this insn sets a function argument, combining it with
2184 something that might need a spill could clobber a previous
2185 function argument; the all_adjacent test in can_combine_p also
2186 checks this; here, we do a more specific test for this case. */
2188 || (REG_P (inner_dest
)
2189 && REGNO (inner_dest
) < FIRST_PSEUDO_REGISTER
2190 && (! HARD_REGNO_MODE_OK (REGNO (inner_dest
),
2191 GET_MODE (inner_dest
))))
2192 || (i1_not_in_src
&& reg_overlap_mentioned_p (i1dest
, src
))
2193 || (i0_not_in_src
&& reg_overlap_mentioned_p (i0dest
, src
)))
2196 /* If DEST is used in I3, it is being killed in this insn, so
2197 record that for later. We have to consider paradoxical
2198 subregs here, since they kill the whole register, but we
2199 ignore partial subregs, STRICT_LOW_PART, etc.
2200 Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the
2201 STACK_POINTER_REGNUM, since these are always considered to be
2202 live. Similarly for ARG_POINTER_REGNUM if it is fixed. */
2204 if (GET_CODE (subdest
) == SUBREG
2205 && (GET_MODE_SIZE (GET_MODE (subdest
))
2206 >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (subdest
)))))
2207 subdest
= SUBREG_REG (subdest
);
2210 && reg_referenced_p (subdest
, PATTERN (i3
))
2211 && REGNO (subdest
) != FRAME_POINTER_REGNUM
2212 && (HARD_FRAME_POINTER_IS_FRAME_POINTER
2213 || REGNO (subdest
) != HARD_FRAME_POINTER_REGNUM
)
2214 && (FRAME_POINTER_REGNUM
== ARG_POINTER_REGNUM
2215 || (REGNO (subdest
) != ARG_POINTER_REGNUM
2216 || ! fixed_regs
[REGNO (subdest
)]))
2217 && REGNO (subdest
) != STACK_POINTER_REGNUM
)
2219 if (*pi3dest_killed
)
2222 *pi3dest_killed
= subdest
;
2226 else if (GET_CODE (x
) == PARALLEL
)
2230 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
2231 if (! combinable_i3pat (i3
, &XVECEXP (x
, 0, i
), i2dest
, i1dest
, i0dest
,
2232 i1_not_in_src
, i0_not_in_src
, pi3dest_killed
))
2239 /* Return 1 if X is an arithmetic expression that contains a multiplication
2240 and division. We don't count multiplications by powers of two here. */
2243 contains_muldiv (rtx x
)
2245 switch (GET_CODE (x
))
2247 case MOD
: case DIV
: case UMOD
: case UDIV
:
2251 return ! (CONST_INT_P (XEXP (x
, 1))
2252 && pow2p_hwi (UINTVAL (XEXP (x
, 1))));
2255 return contains_muldiv (XEXP (x
, 0))
2256 || contains_muldiv (XEXP (x
, 1));
2259 return contains_muldiv (XEXP (x
, 0));
2265 /* Determine whether INSN can be used in a combination. Return nonzero if
2266 not. This is used in try_combine to detect early some cases where we
2267 can't perform combinations. */
2270 cant_combine_insn_p (rtx_insn
*insn
)
2275 /* If this isn't really an insn, we can't do anything.
2276 This can occur when flow deletes an insn that it has merged into an
2277 auto-increment address. */
2278 if (! INSN_P (insn
))
2281 /* Never combine loads and stores involving hard regs that are likely
2282 to be spilled. The register allocator can usually handle such
2283 reg-reg moves by tying. If we allow the combiner to make
2284 substitutions of likely-spilled regs, reload might die.
2285 As an exception, we allow combinations involving fixed regs; these are
2286 not available to the register allocator so there's no risk involved. */
2288 set
= single_set (insn
);
2291 src
= SET_SRC (set
);
2292 dest
= SET_DEST (set
);
2293 if (GET_CODE (src
) == SUBREG
)
2294 src
= SUBREG_REG (src
);
2295 if (GET_CODE (dest
) == SUBREG
)
2296 dest
= SUBREG_REG (dest
);
2297 if (REG_P (src
) && REG_P (dest
)
2298 && ((HARD_REGISTER_P (src
)
2299 && ! TEST_HARD_REG_BIT (fixed_reg_set
, REGNO (src
))
2300 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (REGNO (src
))))
2301 || (HARD_REGISTER_P (dest
)
2302 && ! TEST_HARD_REG_BIT (fixed_reg_set
, REGNO (dest
))
2303 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (REGNO (dest
))))))
2309 struct likely_spilled_retval_info
2311 unsigned regno
, nregs
;
2315 /* Called via note_stores by likely_spilled_retval_p. Remove from info->mask
2316 hard registers that are known to be written to / clobbered in full. */
2318 likely_spilled_retval_1 (rtx x
, const_rtx set
, void *data
)
2320 struct likely_spilled_retval_info
*const info
=
2321 (struct likely_spilled_retval_info
*) data
;
2322 unsigned regno
, nregs
;
2325 if (!REG_P (XEXP (set
, 0)))
2328 if (regno
>= info
->regno
+ info
->nregs
)
2330 nregs
= REG_NREGS (x
);
2331 if (regno
+ nregs
<= info
->regno
)
2333 new_mask
= (2U << (nregs
- 1)) - 1;
2334 if (regno
< info
->regno
)
2335 new_mask
>>= info
->regno
- regno
;
2337 new_mask
<<= regno
- info
->regno
;
2338 info
->mask
&= ~new_mask
;
2341 /* Return nonzero iff part of the return value is live during INSN, and
2342 it is likely spilled. This can happen when more than one insn is needed
2343 to copy the return value, e.g. when we consider to combine into the
2344 second copy insn for a complex value. */
2347 likely_spilled_retval_p (rtx_insn
*insn
)
2349 rtx_insn
*use
= BB_END (this_basic_block
);
2352 unsigned regno
, nregs
;
2353 /* We assume here that no machine mode needs more than
2354 32 hard registers when the value overlaps with a register
2355 for which TARGET_FUNCTION_VALUE_REGNO_P is true. */
2357 struct likely_spilled_retval_info info
;
2359 if (!NONJUMP_INSN_P (use
) || GET_CODE (PATTERN (use
)) != USE
|| insn
== use
)
2361 reg
= XEXP (PATTERN (use
), 0);
2362 if (!REG_P (reg
) || !targetm
.calls
.function_value_regno_p (REGNO (reg
)))
2364 regno
= REGNO (reg
);
2365 nregs
= REG_NREGS (reg
);
2368 mask
= (2U << (nregs
- 1)) - 1;
2370 /* Disregard parts of the return value that are set later. */
2374 for (p
= PREV_INSN (use
); info
.mask
&& p
!= insn
; p
= PREV_INSN (p
))
2376 note_stores (PATTERN (p
), likely_spilled_retval_1
, &info
);
2379 /* Check if any of the (probably) live return value registers is
2384 if ((mask
& 1 << nregs
)
2385 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (regno
+ nregs
)))
2391 /* Adjust INSN after we made a change to its destination.
2393 Changing the destination can invalidate notes that say something about
2394 the results of the insn and a LOG_LINK pointing to the insn. */
2397 adjust_for_new_dest (rtx_insn
*insn
)
2399 /* For notes, be conservative and simply remove them. */
2400 remove_reg_equal_equiv_notes (insn
);
2402 /* The new insn will have a destination that was previously the destination
2403 of an insn just above it. Call distribute_links to make a LOG_LINK from
2404 the next use of that destination. */
2406 rtx set
= single_set (insn
);
2409 rtx reg
= SET_DEST (set
);
2411 while (GET_CODE (reg
) == ZERO_EXTRACT
2412 || GET_CODE (reg
) == STRICT_LOW_PART
2413 || GET_CODE (reg
) == SUBREG
)
2414 reg
= XEXP (reg
, 0);
2415 gcc_assert (REG_P (reg
));
2417 distribute_links (alloc_insn_link (insn
, REGNO (reg
), NULL
));
2419 df_insn_rescan (insn
);
2422 /* Return TRUE if combine can reuse reg X in mode MODE.
2423 ADDED_SETS is nonzero if the original set is still required. */
2425 can_change_dest_mode (rtx x
, int added_sets
, machine_mode mode
)
2433 /* Allow hard registers if the new mode is legal, and occupies no more
2434 registers than the old mode. */
2435 if (regno
< FIRST_PSEUDO_REGISTER
)
2436 return (HARD_REGNO_MODE_OK (regno
, mode
)
2437 && REG_NREGS (x
) >= hard_regno_nregs
[regno
][mode
]);
2439 /* Or a pseudo that is only used once. */
2440 return (regno
< reg_n_sets_max
2441 && REG_N_SETS (regno
) == 1
2443 && !REG_USERVAR_P (x
));
2447 /* Check whether X, the destination of a set, refers to part of
2448 the register specified by REG. */
2451 reg_subword_p (rtx x
, rtx reg
)
2453 /* Check that reg is an integer mode register. */
2454 if (!REG_P (reg
) || GET_MODE_CLASS (GET_MODE (reg
)) != MODE_INT
)
2457 if (GET_CODE (x
) == STRICT_LOW_PART
2458 || GET_CODE (x
) == ZERO_EXTRACT
)
2461 return GET_CODE (x
) == SUBREG
2462 && SUBREG_REG (x
) == reg
2463 && GET_MODE_CLASS (GET_MODE (x
)) == MODE_INT
;
2466 /* Delete the unconditional jump INSN and adjust the CFG correspondingly.
2467 Note that the INSN should be deleted *after* removing dead edges, so
2468 that the kept edge is the fallthrough edge for a (set (pc) (pc))
2469 but not for a (set (pc) (label_ref FOO)). */
2472 update_cfg_for_uncondjump (rtx_insn
*insn
)
2474 basic_block bb
= BLOCK_FOR_INSN (insn
);
2475 gcc_assert (BB_END (bb
) == insn
);
2477 purge_dead_edges (bb
);
2480 if (EDGE_COUNT (bb
->succs
) == 1)
2484 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2486 /* Remove barriers from the footer if there are any. */
2487 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2488 if (BARRIER_P (insn
))
2490 if (PREV_INSN (insn
))
2491 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2493 BB_FOOTER (bb
) = NEXT_INSN (insn
);
2494 if (NEXT_INSN (insn
))
2495 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2497 else if (LABEL_P (insn
))
2502 /* Return whether PAT is a PARALLEL of exactly N register SETs followed
2503 by an arbitrary number of CLOBBERs. */
2505 is_parallel_of_n_reg_sets (rtx pat
, int n
)
2507 if (GET_CODE (pat
) != PARALLEL
)
2510 int len
= XVECLEN (pat
, 0);
2515 for (i
= 0; i
< n
; i
++)
2516 if (GET_CODE (XVECEXP (pat
, 0, i
)) != SET
2517 || !REG_P (SET_DEST (XVECEXP (pat
, 0, i
))))
2519 for ( ; i
< len
; i
++)
2520 if (GET_CODE (XVECEXP (pat
, 0, i
)) != CLOBBER
2521 || XEXP (XVECEXP (pat
, 0, i
), 0) == const0_rtx
)
2527 /* Return whether INSN, a PARALLEL of N register SETs (and maybe some
2528 CLOBBERs), can be split into individual SETs in that order, without
2529 changing semantics. */
2531 can_split_parallel_of_n_reg_sets (rtx_insn
*insn
, int n
)
2533 if (!insn_nothrow_p (insn
))
2536 rtx pat
= PATTERN (insn
);
2539 for (i
= 0; i
< n
; i
++)
2541 if (side_effects_p (SET_SRC (XVECEXP (pat
, 0, i
))))
2544 rtx reg
= SET_DEST (XVECEXP (pat
, 0, i
));
2546 for (j
= i
+ 1; j
< n
; j
++)
2547 if (reg_referenced_p (reg
, XVECEXP (pat
, 0, j
)))
2554 /* Try to combine the insns I0, I1 and I2 into I3.
2555 Here I0, I1 and I2 appear earlier than I3.
2556 I0 and I1 can be zero; then we combine just I2 into I3, or I1 and I2 into
2559 If we are combining more than two insns and the resulting insn is not
2560 recognized, try splitting it into two insns. If that happens, I2 and I3
2561 are retained and I1/I0 are pseudo-deleted by turning them into a NOTE.
2562 Otherwise, I0, I1 and I2 are pseudo-deleted.
2564 Return 0 if the combination does not work. Then nothing is changed.
2565 If we did the combination, return the insn at which combine should
2568 Set NEW_DIRECT_JUMP_P to a nonzero value if try_combine creates a
2569 new direct jump instruction.
2571 LAST_COMBINED_INSN is either I3, or some insn after I3 that has
2572 been I3 passed to an earlier try_combine within the same basic
2576 try_combine (rtx_insn
*i3
, rtx_insn
*i2
, rtx_insn
*i1
, rtx_insn
*i0
,
2577 int *new_direct_jump_p
, rtx_insn
*last_combined_insn
)
2579 /* New patterns for I3 and I2, respectively. */
2580 rtx newpat
, newi2pat
= 0;
2581 rtvec newpat_vec_with_clobbers
= 0;
2582 int substed_i2
= 0, substed_i1
= 0, substed_i0
= 0;
2583 /* Indicates need to preserve SET in I0, I1 or I2 in I3 if it is not
2585 int added_sets_0
, added_sets_1
, added_sets_2
;
2586 /* Total number of SETs to put into I3. */
2588 /* Nonzero if I2's or I1's body now appears in I3. */
2589 int i2_is_used
= 0, i1_is_used
= 0;
2590 /* INSN_CODEs for new I3, new I2, and user of condition code. */
2591 int insn_code_number
, i2_code_number
= 0, other_code_number
= 0;
2592 /* Contains I3 if the destination of I3 is used in its source, which means
2593 that the old life of I3 is being killed. If that usage is placed into
2594 I2 and not in I3, a REG_DEAD note must be made. */
2595 rtx i3dest_killed
= 0;
2596 /* SET_DEST and SET_SRC of I2, I1 and I0. */
2597 rtx i2dest
= 0, i2src
= 0, i1dest
= 0, i1src
= 0, i0dest
= 0, i0src
= 0;
2598 /* Copy of SET_SRC of I1 and I0, if needed. */
2599 rtx i1src_copy
= 0, i0src_copy
= 0, i0src_copy2
= 0;
2600 /* Set if I2DEST was reused as a scratch register. */
2601 bool i2scratch
= false;
2602 /* The PATTERNs of I0, I1, and I2, or a copy of them in certain cases. */
2603 rtx i0pat
= 0, i1pat
= 0, i2pat
= 0;
2604 /* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */
2605 int i2dest_in_i2src
= 0, i1dest_in_i1src
= 0, i2dest_in_i1src
= 0;
2606 int i0dest_in_i0src
= 0, i1dest_in_i0src
= 0, i2dest_in_i0src
= 0;
2607 int i2dest_killed
= 0, i1dest_killed
= 0, i0dest_killed
= 0;
2608 int i1_feeds_i2_n
= 0, i0_feeds_i2_n
= 0, i0_feeds_i1_n
= 0;
2609 /* Notes that must be added to REG_NOTES in I3 and I2. */
2610 rtx new_i3_notes
, new_i2_notes
;
2611 /* Notes that we substituted I3 into I2 instead of the normal case. */
2612 int i3_subst_into_i2
= 0;
2613 /* Notes that I1, I2 or I3 is a MULT operation. */
2616 int changed_i3_dest
= 0;
2619 rtx_insn
*temp_insn
;
2621 struct insn_link
*link
;
2623 rtx new_other_notes
;
2626 /* Immediately return if any of I0,I1,I2 are the same insn (I3 can
2628 if (i1
== i2
|| i0
== i2
|| (i0
&& i0
== i1
))
2631 /* Only try four-insn combinations when there's high likelihood of
2632 success. Look for simple insns, such as loads of constants or
2633 binary operations involving a constant. */
2641 if (!flag_expensive_optimizations
)
2644 for (i
= 0; i
< 4; i
++)
2646 rtx_insn
*insn
= i
== 0 ? i0
: i
== 1 ? i1
: i
== 2 ? i2
: i3
;
2647 rtx set
= single_set (insn
);
2651 src
= SET_SRC (set
);
2652 if (CONSTANT_P (src
))
2657 else if (BINARY_P (src
) && CONSTANT_P (XEXP (src
, 1)))
2659 else if (GET_CODE (src
) == ASHIFT
|| GET_CODE (src
) == ASHIFTRT
2660 || GET_CODE (src
) == LSHIFTRT
)
2664 /* If I0 loads a memory and I3 sets the same memory, then I1 and I2
2665 are likely manipulating its value. Ideally we'll be able to combine
2666 all four insns into a bitfield insertion of some kind.
2668 Note the source in I0 might be inside a sign/zero extension and the
2669 memory modes in I0 and I3 might be different. So extract the address
2670 from the destination of I3 and search for it in the source of I0.
2672 In the event that there's a match but the source/dest do not actually
2673 refer to the same memory, the worst that happens is we try some
2674 combinations that we wouldn't have otherwise. */
2675 if ((set0
= single_set (i0
))
2676 /* Ensure the source of SET0 is a MEM, possibly buried inside
2678 && (GET_CODE (SET_SRC (set0
)) == MEM
2679 || ((GET_CODE (SET_SRC (set0
)) == ZERO_EXTEND
2680 || GET_CODE (SET_SRC (set0
)) == SIGN_EXTEND
)
2681 && GET_CODE (XEXP (SET_SRC (set0
), 0)) == MEM
))
2682 && (set3
= single_set (i3
))
2683 /* Ensure the destination of SET3 is a MEM. */
2684 && GET_CODE (SET_DEST (set3
)) == MEM
2685 /* Would it be better to extract the base address for the MEM
2686 in SET3 and look for that? I don't have cases where it matters
2687 but I could envision such cases. */
2688 && rtx_referenced_p (XEXP (SET_DEST (set3
), 0), SET_SRC (set0
)))
2691 if (ngood
< 2 && nshift
< 2)
2695 /* Exit early if one of the insns involved can't be used for
2698 || (i1
&& CALL_P (i1
))
2699 || (i0
&& CALL_P (i0
))
2700 || cant_combine_insn_p (i3
)
2701 || cant_combine_insn_p (i2
)
2702 || (i1
&& cant_combine_insn_p (i1
))
2703 || (i0
&& cant_combine_insn_p (i0
))
2704 || likely_spilled_retval_p (i3
))
2708 undobuf
.other_insn
= 0;
2710 /* Reset the hard register usage information. */
2711 CLEAR_HARD_REG_SET (newpat_used_regs
);
2713 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2716 fprintf (dump_file
, "\nTrying %d, %d, %d -> %d:\n",
2717 INSN_UID (i0
), INSN_UID (i1
), INSN_UID (i2
), INSN_UID (i3
));
2719 fprintf (dump_file
, "\nTrying %d, %d -> %d:\n",
2720 INSN_UID (i1
), INSN_UID (i2
), INSN_UID (i3
));
2722 fprintf (dump_file
, "\nTrying %d -> %d:\n",
2723 INSN_UID (i2
), INSN_UID (i3
));
2726 /* If multiple insns feed into one of I2 or I3, they can be in any
2727 order. To simplify the code below, reorder them in sequence. */
2728 if (i0
&& DF_INSN_LUID (i0
) > DF_INSN_LUID (i2
))
2730 if (i0
&& DF_INSN_LUID (i0
) > DF_INSN_LUID (i1
))
2732 if (i1
&& DF_INSN_LUID (i1
) > DF_INSN_LUID (i2
))
2735 added_links_insn
= 0;
2737 /* First check for one important special case that the code below will
2738 not handle. Namely, the case where I1 is zero, I2 is a PARALLEL
2739 and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case,
2740 we may be able to replace that destination with the destination of I3.
2741 This occurs in the common code where we compute both a quotient and
2742 remainder into a structure, in which case we want to do the computation
2743 directly into the structure to avoid register-register copies.
2745 Note that this case handles both multiple sets in I2 and also cases
2746 where I2 has a number of CLOBBERs inside the PARALLEL.
2748 We make very conservative checks below and only try to handle the
2749 most common cases of this. For example, we only handle the case
2750 where I2 and I3 are adjacent to avoid making difficult register
2753 if (i1
== 0 && NONJUMP_INSN_P (i3
) && GET_CODE (PATTERN (i3
)) == SET
2754 && REG_P (SET_SRC (PATTERN (i3
)))
2755 && REGNO (SET_SRC (PATTERN (i3
))) >= FIRST_PSEUDO_REGISTER
2756 && find_reg_note (i3
, REG_DEAD
, SET_SRC (PATTERN (i3
)))
2757 && GET_CODE (PATTERN (i2
)) == PARALLEL
2758 && ! side_effects_p (SET_DEST (PATTERN (i3
)))
2759 /* If the dest of I3 is a ZERO_EXTRACT or STRICT_LOW_PART, the code
2760 below would need to check what is inside (and reg_overlap_mentioned_p
2761 doesn't support those codes anyway). Don't allow those destinations;
2762 the resulting insn isn't likely to be recognized anyway. */
2763 && GET_CODE (SET_DEST (PATTERN (i3
))) != ZERO_EXTRACT
2764 && GET_CODE (SET_DEST (PATTERN (i3
))) != STRICT_LOW_PART
2765 && ! reg_overlap_mentioned_p (SET_SRC (PATTERN (i3
)),
2766 SET_DEST (PATTERN (i3
)))
2767 && next_active_insn (i2
) == i3
)
2769 rtx p2
= PATTERN (i2
);
2771 /* Make sure that the destination of I3,
2772 which we are going to substitute into one output of I2,
2773 is not used within another output of I2. We must avoid making this:
2774 (parallel [(set (mem (reg 69)) ...)
2775 (set (reg 69) ...)])
2776 which is not well-defined as to order of actions.
2777 (Besides, reload can't handle output reloads for this.)
2779 The problem can also happen if the dest of I3 is a memory ref,
2780 if another dest in I2 is an indirect memory ref. */
2781 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2782 if ((GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2783 || GET_CODE (XVECEXP (p2
, 0, i
)) == CLOBBER
)
2784 && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3
)),
2785 SET_DEST (XVECEXP (p2
, 0, i
))))
2788 /* Make sure this PARALLEL is not an asm. We do not allow combining
2789 that usually (see can_combine_p), so do not here either. */
2790 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2791 if (GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2792 && GET_CODE (SET_SRC (XVECEXP (p2
, 0, i
))) == ASM_OPERANDS
)
2795 if (i
== XVECLEN (p2
, 0))
2796 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2797 if (GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2798 && SET_DEST (XVECEXP (p2
, 0, i
)) == SET_SRC (PATTERN (i3
)))
2803 subst_low_luid
= DF_INSN_LUID (i2
);
2805 added_sets_2
= added_sets_1
= added_sets_0
= 0;
2806 i2src
= SET_SRC (XVECEXP (p2
, 0, i
));
2807 i2dest
= SET_DEST (XVECEXP (p2
, 0, i
));
2808 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2810 /* Replace the dest in I2 with our dest and make the resulting
2811 insn the new pattern for I3. Then skip to where we validate
2812 the pattern. Everything was set up above. */
2813 SUBST (SET_DEST (XVECEXP (p2
, 0, i
)), SET_DEST (PATTERN (i3
)));
2815 i3_subst_into_i2
= 1;
2816 goto validate_replacement
;
2820 /* If I2 is setting a pseudo to a constant and I3 is setting some
2821 sub-part of it to another constant, merge them by making a new
2824 && (temp_expr
= single_set (i2
)) != 0
2825 && CONST_SCALAR_INT_P (SET_SRC (temp_expr
))
2826 && GET_CODE (PATTERN (i3
)) == SET
2827 && CONST_SCALAR_INT_P (SET_SRC (PATTERN (i3
)))
2828 && reg_subword_p (SET_DEST (PATTERN (i3
)), SET_DEST (temp_expr
)))
2830 rtx dest
= SET_DEST (PATTERN (i3
));
2834 if (GET_CODE (dest
) == ZERO_EXTRACT
)
2836 if (CONST_INT_P (XEXP (dest
, 1))
2837 && CONST_INT_P (XEXP (dest
, 2)))
2839 width
= INTVAL (XEXP (dest
, 1));
2840 offset
= INTVAL (XEXP (dest
, 2));
2841 dest
= XEXP (dest
, 0);
2842 if (BITS_BIG_ENDIAN
)
2843 offset
= GET_MODE_PRECISION (GET_MODE (dest
)) - width
- offset
;
2848 if (GET_CODE (dest
) == STRICT_LOW_PART
)
2849 dest
= XEXP (dest
, 0);
2850 width
= GET_MODE_PRECISION (GET_MODE (dest
));
2856 /* If this is the low part, we're done. */
2857 if (subreg_lowpart_p (dest
))
2859 /* Handle the case where inner is twice the size of outer. */
2860 else if (GET_MODE_PRECISION (GET_MODE (SET_DEST (temp_expr
)))
2861 == 2 * GET_MODE_PRECISION (GET_MODE (dest
)))
2862 offset
+= GET_MODE_PRECISION (GET_MODE (dest
));
2863 /* Otherwise give up for now. */
2870 rtx inner
= SET_SRC (PATTERN (i3
));
2871 rtx outer
= SET_SRC (temp_expr
);
2874 = wi::insert (rtx_mode_t (outer
, GET_MODE (SET_DEST (temp_expr
))),
2875 rtx_mode_t (inner
, GET_MODE (dest
)),
2880 subst_low_luid
= DF_INSN_LUID (i2
);
2881 added_sets_2
= added_sets_1
= added_sets_0
= 0;
2882 i2dest
= SET_DEST (temp_expr
);
2883 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2885 /* Replace the source in I2 with the new constant and make the
2886 resulting insn the new pattern for I3. Then skip to where we
2887 validate the pattern. Everything was set up above. */
2888 SUBST (SET_SRC (temp_expr
),
2889 immed_wide_int_const (o
, GET_MODE (SET_DEST (temp_expr
))));
2891 newpat
= PATTERN (i2
);
2893 /* The dest of I3 has been replaced with the dest of I2. */
2894 changed_i3_dest
= 1;
2895 goto validate_replacement
;
2899 /* If we have no I1 and I2 looks like:
2900 (parallel [(set (reg:CC X) (compare:CC OP (const_int 0)))
2902 make up a dummy I1 that is
2905 (set (reg:CC X) (compare:CC Y (const_int 0)))
2907 (We can ignore any trailing CLOBBERs.)
2909 This undoes a previous combination and allows us to match a branch-and-
2912 if (!HAVE_cc0
&& i1
== 0
2913 && is_parallel_of_n_reg_sets (PATTERN (i2
), 2)
2914 && (GET_MODE_CLASS (GET_MODE (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0))))
2916 && GET_CODE (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0))) == COMPARE
2917 && XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 1) == const0_rtx
2918 && rtx_equal_p (XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 0),
2919 SET_SRC (XVECEXP (PATTERN (i2
), 0, 1)))
2920 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0)), i2
, i3
)
2921 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 1)), i2
, i3
))
2923 /* We make I1 with the same INSN_UID as I2. This gives it
2924 the same DF_INSN_LUID for value tracking. Our fake I1 will
2925 never appear in the insn stream so giving it the same INSN_UID
2926 as I2 will not cause a problem. */
2928 i1
= gen_rtx_INSN (VOIDmode
, NULL
, i2
, BLOCK_FOR_INSN (i2
),
2929 XVECEXP (PATTERN (i2
), 0, 1), INSN_LOCATION (i2
),
2931 INSN_UID (i1
) = INSN_UID (i2
);
2933 SUBST (PATTERN (i2
), XVECEXP (PATTERN (i2
), 0, 0));
2934 SUBST (XEXP (SET_SRC (PATTERN (i2
)), 0),
2935 SET_DEST (PATTERN (i1
)));
2936 unsigned int regno
= REGNO (SET_DEST (PATTERN (i1
)));
2937 SUBST_LINK (LOG_LINKS (i2
),
2938 alloc_insn_link (i1
, regno
, LOG_LINKS (i2
)));
2941 /* If I2 is a PARALLEL of two SETs of REGs (and perhaps some CLOBBERs),
2942 make those two SETs separate I1 and I2 insns, and make an I0 that is
2944 if (!HAVE_cc0
&& i0
== 0
2945 && is_parallel_of_n_reg_sets (PATTERN (i2
), 2)
2946 && can_split_parallel_of_n_reg_sets (i2
, 2)
2947 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0)), i2
, i3
)
2948 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 1)), i2
, i3
))
2950 /* If there is no I1, there is no I0 either. */
2953 /* We make I1 with the same INSN_UID as I2. This gives it
2954 the same DF_INSN_LUID for value tracking. Our fake I1 will
2955 never appear in the insn stream so giving it the same INSN_UID
2956 as I2 will not cause a problem. */
2958 i1
= gen_rtx_INSN (VOIDmode
, NULL
, i2
, BLOCK_FOR_INSN (i2
),
2959 XVECEXP (PATTERN (i2
), 0, 0), INSN_LOCATION (i2
),
2961 INSN_UID (i1
) = INSN_UID (i2
);
2963 SUBST (PATTERN (i2
), XVECEXP (PATTERN (i2
), 0, 1));
2966 /* Verify that I2 and I1 are valid for combining. */
2967 if (! can_combine_p (i2
, i3
, i0
, i1
, NULL
, NULL
, &i2dest
, &i2src
)
2968 || (i1
&& ! can_combine_p (i1
, i3
, i0
, NULL
, i2
, NULL
,
2970 || (i0
&& ! can_combine_p (i0
, i3
, NULL
, NULL
, i1
, i2
,
2977 /* Record whether I2DEST is used in I2SRC and similarly for the other
2978 cases. Knowing this will help in register status updating below. */
2979 i2dest_in_i2src
= reg_overlap_mentioned_p (i2dest
, i2src
);
2980 i1dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i1dest
, i1src
);
2981 i2dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i2dest
, i1src
);
2982 i0dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i0dest
, i0src
);
2983 i1dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i1dest
, i0src
);
2984 i2dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i2dest
, i0src
);
2985 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2986 i1dest_killed
= i1
&& dead_or_set_p (i1
, i1dest
);
2987 i0dest_killed
= i0
&& dead_or_set_p (i0
, i0dest
);
2989 /* For the earlier insns, determine which of the subsequent ones they
2991 i1_feeds_i2_n
= i1
&& insn_a_feeds_b (i1
, i2
);
2992 i0_feeds_i1_n
= i0
&& insn_a_feeds_b (i0
, i1
);
2993 i0_feeds_i2_n
= (i0
&& (!i0_feeds_i1_n
? insn_a_feeds_b (i0
, i2
)
2994 : (!reg_overlap_mentioned_p (i1dest
, i0dest
)
2995 && reg_overlap_mentioned_p (i0dest
, i2src
))));
2997 /* Ensure that I3's pattern can be the destination of combines. */
2998 if (! combinable_i3pat (i3
, &PATTERN (i3
), i2dest
, i1dest
, i0dest
,
2999 i1
&& i2dest_in_i1src
&& !i1_feeds_i2_n
,
3000 i0
&& ((i2dest_in_i0src
&& !i0_feeds_i2_n
)
3001 || (i1dest_in_i0src
&& !i0_feeds_i1_n
)),
3008 /* See if any of the insns is a MULT operation. Unless one is, we will
3009 reject a combination that is, since it must be slower. Be conservative
3011 if (GET_CODE (i2src
) == MULT
3012 || (i1
!= 0 && GET_CODE (i1src
) == MULT
)
3013 || (i0
!= 0 && GET_CODE (i0src
) == MULT
)
3014 || (GET_CODE (PATTERN (i3
)) == SET
3015 && GET_CODE (SET_SRC (PATTERN (i3
))) == MULT
))
3018 /* If I3 has an inc, then give up if I1 or I2 uses the reg that is inc'd.
3019 We used to do this EXCEPT in one case: I3 has a post-inc in an
3020 output operand. However, that exception can give rise to insns like
3022 which is a famous insn on the PDP-11 where the value of r3 used as the
3023 source was model-dependent. Avoid this sort of thing. */
3026 if (!(GET_CODE (PATTERN (i3
)) == SET
3027 && REG_P (SET_SRC (PATTERN (i3
)))
3028 && MEM_P (SET_DEST (PATTERN (i3
)))
3029 && (GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_INC
3030 || GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_DEC
)))
3031 /* It's not the exception. */
3036 for (link
= REG_NOTES (i3
); link
; link
= XEXP (link
, 1))
3037 if (REG_NOTE_KIND (link
) == REG_INC
3038 && (reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i2
))
3040 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i1
)))))
3047 /* See if the SETs in I1 or I2 need to be kept around in the merged
3048 instruction: whenever the value set there is still needed past I3.
3049 For the SET in I2, this is easy: we see if I2DEST dies or is set in I3.
3051 For the SET in I1, we have two cases: if I1 and I2 independently feed
3052 into I3, the set in I1 needs to be kept around unless I1DEST dies
3053 or is set in I3. Otherwise (if I1 feeds I2 which feeds I3), the set
3054 in I1 needs to be kept around unless I1DEST dies or is set in either
3055 I2 or I3. The same considerations apply to I0. */
3057 added_sets_2
= !dead_or_set_p (i3
, i2dest
);
3060 added_sets_1
= !(dead_or_set_p (i3
, i1dest
)
3061 || (i1_feeds_i2_n
&& dead_or_set_p (i2
, i1dest
)));
3066 added_sets_0
= !(dead_or_set_p (i3
, i0dest
)
3067 || (i0_feeds_i1_n
&& dead_or_set_p (i1
, i0dest
))
3068 || ((i0_feeds_i2_n
|| (i0_feeds_i1_n
&& i1_feeds_i2_n
))
3069 && dead_or_set_p (i2
, i0dest
)));
3073 /* We are about to copy insns for the case where they need to be kept
3074 around. Check that they can be copied in the merged instruction. */
3076 if (targetm
.cannot_copy_insn_p
3077 && ((added_sets_2
&& targetm
.cannot_copy_insn_p (i2
))
3078 || (i1
&& added_sets_1
&& targetm
.cannot_copy_insn_p (i1
))
3079 || (i0
&& added_sets_0
&& targetm
.cannot_copy_insn_p (i0
))))
3085 /* If the set in I2 needs to be kept around, we must make a copy of
3086 PATTERN (I2), so that when we substitute I1SRC for I1DEST in
3087 PATTERN (I2), we are only substituting for the original I1DEST, not into
3088 an already-substituted copy. This also prevents making self-referential
3089 rtx. If I2 is a PARALLEL, we just need the piece that assigns I2SRC to
3094 if (GET_CODE (PATTERN (i2
)) == PARALLEL
)
3095 i2pat
= gen_rtx_SET (i2dest
, copy_rtx (i2src
));
3097 i2pat
= copy_rtx (PATTERN (i2
));
3102 if (GET_CODE (PATTERN (i1
)) == PARALLEL
)
3103 i1pat
= gen_rtx_SET (i1dest
, copy_rtx (i1src
));
3105 i1pat
= copy_rtx (PATTERN (i1
));
3110 if (GET_CODE (PATTERN (i0
)) == PARALLEL
)
3111 i0pat
= gen_rtx_SET (i0dest
, copy_rtx (i0src
));
3113 i0pat
= copy_rtx (PATTERN (i0
));
3118 /* Substitute in the latest insn for the regs set by the earlier ones. */
3120 maxreg
= max_reg_num ();
3124 /* Many machines that don't use CC0 have insns that can both perform an
3125 arithmetic operation and set the condition code. These operations will
3126 be represented as a PARALLEL with the first element of the vector
3127 being a COMPARE of an arithmetic operation with the constant zero.
3128 The second element of the vector will set some pseudo to the result
3129 of the same arithmetic operation. If we simplify the COMPARE, we won't
3130 match such a pattern and so will generate an extra insn. Here we test
3131 for this case, where both the comparison and the operation result are
3132 needed, and make the PARALLEL by just replacing I2DEST in I3SRC with
3133 I2SRC. Later we will make the PARALLEL that contains I2. */
3135 if (!HAVE_cc0
&& i1
== 0 && added_sets_2
&& GET_CODE (PATTERN (i3
)) == SET
3136 && GET_CODE (SET_SRC (PATTERN (i3
))) == COMPARE
3137 && CONST_INT_P (XEXP (SET_SRC (PATTERN (i3
)), 1))
3138 && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3
)), 0), i2dest
))
3141 rtx
*cc_use_loc
= NULL
;
3142 rtx_insn
*cc_use_insn
= NULL
;
3143 rtx op0
= i2src
, op1
= XEXP (SET_SRC (PATTERN (i3
)), 1);
3144 machine_mode compare_mode
, orig_compare_mode
;
3145 enum rtx_code compare_code
= UNKNOWN
, orig_compare_code
= UNKNOWN
;
3147 newpat
= PATTERN (i3
);
3148 newpat_dest
= SET_DEST (newpat
);
3149 compare_mode
= orig_compare_mode
= GET_MODE (newpat_dest
);
3151 if (undobuf
.other_insn
== 0
3152 && (cc_use_loc
= find_single_use (SET_DEST (newpat
), i3
,
3155 compare_code
= orig_compare_code
= GET_CODE (*cc_use_loc
);
3156 compare_code
= simplify_compare_const (compare_code
,
3157 GET_MODE (i2dest
), op0
, &op1
);
3158 target_canonicalize_comparison (&compare_code
, &op0
, &op1
, 1);
3161 /* Do the rest only if op1 is const0_rtx, which may be the
3162 result of simplification. */
3163 if (op1
== const0_rtx
)
3165 /* If a single use of the CC is found, prepare to modify it
3166 when SELECT_CC_MODE returns a new CC-class mode, or when
3167 the above simplify_compare_const() returned a new comparison
3168 operator. undobuf.other_insn is assigned the CC use insn
3169 when modifying it. */
3172 #ifdef SELECT_CC_MODE
3173 machine_mode new_mode
3174 = SELECT_CC_MODE (compare_code
, op0
, op1
);
3175 if (new_mode
!= orig_compare_mode
3176 && can_change_dest_mode (SET_DEST (newpat
),
3177 added_sets_2
, new_mode
))
3179 unsigned int regno
= REGNO (newpat_dest
);
3180 compare_mode
= new_mode
;
3181 if (regno
< FIRST_PSEUDO_REGISTER
)
3182 newpat_dest
= gen_rtx_REG (compare_mode
, regno
);
3185 SUBST_MODE (regno_reg_rtx
[regno
], compare_mode
);
3186 newpat_dest
= regno_reg_rtx
[regno
];
3190 /* Cases for modifying the CC-using comparison. */
3191 if (compare_code
!= orig_compare_code
3192 /* ??? Do we need to verify the zero rtx? */
3193 && XEXP (*cc_use_loc
, 1) == const0_rtx
)
3195 /* Replace cc_use_loc with entire new RTX. */
3197 gen_rtx_fmt_ee (compare_code
, compare_mode
,
3198 newpat_dest
, const0_rtx
));
3199 undobuf
.other_insn
= cc_use_insn
;
3201 else if (compare_mode
!= orig_compare_mode
)
3203 /* Just replace the CC reg with a new mode. */
3204 SUBST (XEXP (*cc_use_loc
, 0), newpat_dest
);
3205 undobuf
.other_insn
= cc_use_insn
;
3209 /* Now we modify the current newpat:
3210 First, SET_DEST(newpat) is updated if the CC mode has been
3211 altered. For targets without SELECT_CC_MODE, this should be
3213 if (compare_mode
!= orig_compare_mode
)
3214 SUBST (SET_DEST (newpat
), newpat_dest
);
3215 /* This is always done to propagate i2src into newpat. */
3216 SUBST (SET_SRC (newpat
),
3217 gen_rtx_COMPARE (compare_mode
, op0
, op1
));
3218 /* Create new version of i2pat if needed; the below PARALLEL
3219 creation needs this to work correctly. */
3220 if (! rtx_equal_p (i2src
, op0
))
3221 i2pat
= gen_rtx_SET (i2dest
, op0
);
3226 if (i2_is_used
== 0)
3228 /* It is possible that the source of I2 or I1 may be performing
3229 an unneeded operation, such as a ZERO_EXTEND of something
3230 that is known to have the high part zero. Handle that case
3231 by letting subst look at the inner insns.
3233 Another way to do this would be to have a function that tries
3234 to simplify a single insn instead of merging two or more
3235 insns. We don't do this because of the potential of infinite
3236 loops and because of the potential extra memory required.
3237 However, doing it the way we are is a bit of a kludge and
3238 doesn't catch all cases.
3240 But only do this if -fexpensive-optimizations since it slows
3241 things down and doesn't usually win.
3243 This is not done in the COMPARE case above because the
3244 unmodified I2PAT is used in the PARALLEL and so a pattern
3245 with a modified I2SRC would not match. */
3247 if (flag_expensive_optimizations
)
3249 /* Pass pc_rtx so no substitutions are done, just
3253 subst_low_luid
= DF_INSN_LUID (i1
);
3254 i1src
= subst (i1src
, pc_rtx
, pc_rtx
, 0, 0, 0);
3257 subst_low_luid
= DF_INSN_LUID (i2
);
3258 i2src
= subst (i2src
, pc_rtx
, pc_rtx
, 0, 0, 0);
3261 n_occurrences
= 0; /* `subst' counts here */
3262 subst_low_luid
= DF_INSN_LUID (i2
);
3264 /* If I1 feeds into I2 and I1DEST is in I1SRC, we need to make a unique
3265 copy of I2SRC each time we substitute it, in order to avoid creating
3266 self-referential RTL when we will be substituting I1SRC for I1DEST
3267 later. Likewise if I0 feeds into I2, either directly or indirectly
3268 through I1, and I0DEST is in I0SRC. */
3269 newpat
= subst (PATTERN (i3
), i2dest
, i2src
, 0, 0,
3270 (i1_feeds_i2_n
&& i1dest_in_i1src
)
3271 || ((i0_feeds_i2_n
|| (i0_feeds_i1_n
&& i1_feeds_i2_n
))
3272 && i0dest_in_i0src
));
3275 /* Record whether I2's body now appears within I3's body. */
3276 i2_is_used
= n_occurrences
;
3279 /* If we already got a failure, don't try to do more. Otherwise, try to
3280 substitute I1 if we have it. */
3282 if (i1
&& GET_CODE (newpat
) != CLOBBER
)
3284 /* Check that an autoincrement side-effect on I1 has not been lost.
3285 This happens if I1DEST is mentioned in I2 and dies there, and
3286 has disappeared from the new pattern. */
3287 if ((FIND_REG_INC_NOTE (i1
, NULL_RTX
) != 0
3289 && dead_or_set_p (i2
, i1dest
)
3290 && !reg_overlap_mentioned_p (i1dest
, newpat
))
3291 /* Before we can do this substitution, we must redo the test done
3292 above (see detailed comments there) that ensures I1DEST isn't
3293 mentioned in any SETs in NEWPAT that are field assignments. */
3294 || !combinable_i3pat (NULL
, &newpat
, i1dest
, NULL_RTX
, NULL_RTX
,
3302 subst_low_luid
= DF_INSN_LUID (i1
);
3304 /* If the following substitution will modify I1SRC, make a copy of it
3305 for the case where it is substituted for I1DEST in I2PAT later. */
3306 if (added_sets_2
&& i1_feeds_i2_n
)
3307 i1src_copy
= copy_rtx (i1src
);
3309 /* If I0 feeds into I1 and I0DEST is in I0SRC, we need to make a unique
3310 copy of I1SRC each time we substitute it, in order to avoid creating
3311 self-referential RTL when we will be substituting I0SRC for I0DEST
3313 newpat
= subst (newpat
, i1dest
, i1src
, 0, 0,
3314 i0_feeds_i1_n
&& i0dest_in_i0src
);
3317 /* Record whether I1's body now appears within I3's body. */
3318 i1_is_used
= n_occurrences
;
3321 /* Likewise for I0 if we have it. */
3323 if (i0
&& GET_CODE (newpat
) != CLOBBER
)
3325 if ((FIND_REG_INC_NOTE (i0
, NULL_RTX
) != 0
3326 && ((i0_feeds_i2_n
&& dead_or_set_p (i2
, i0dest
))
3327 || (i0_feeds_i1_n
&& dead_or_set_p (i1
, i0dest
)))
3328 && !reg_overlap_mentioned_p (i0dest
, newpat
))
3329 || !combinable_i3pat (NULL
, &newpat
, i0dest
, NULL_RTX
, NULL_RTX
,
3336 /* If the following substitution will modify I0SRC, make a copy of it
3337 for the case where it is substituted for I0DEST in I1PAT later. */
3338 if (added_sets_1
&& i0_feeds_i1_n
)
3339 i0src_copy
= copy_rtx (i0src
);
3340 /* And a copy for I0DEST in I2PAT substitution. */
3341 if (added_sets_2
&& ((i0_feeds_i1_n
&& i1_feeds_i2_n
)
3342 || (i0_feeds_i2_n
)))
3343 i0src_copy2
= copy_rtx (i0src
);
3346 subst_low_luid
= DF_INSN_LUID (i0
);
3347 newpat
= subst (newpat
, i0dest
, i0src
, 0, 0, 0);
3351 /* Fail if an autoincrement side-effect has been duplicated. Be careful
3352 to count all the ways that I2SRC and I1SRC can be used. */
3353 if ((FIND_REG_INC_NOTE (i2
, NULL_RTX
) != 0
3354 && i2_is_used
+ added_sets_2
> 1)
3355 || (i1
!= 0 && FIND_REG_INC_NOTE (i1
, NULL_RTX
) != 0
3356 && (i1_is_used
+ added_sets_1
+ (added_sets_2
&& i1_feeds_i2_n
)
3358 || (i0
!= 0 && FIND_REG_INC_NOTE (i0
, NULL_RTX
) != 0
3359 && (n_occurrences
+ added_sets_0
3360 + (added_sets_1
&& i0_feeds_i1_n
)
3361 + (added_sets_2
&& i0_feeds_i2_n
)
3363 /* Fail if we tried to make a new register. */
3364 || max_reg_num () != maxreg
3365 /* Fail if we couldn't do something and have a CLOBBER. */
3366 || GET_CODE (newpat
) == CLOBBER
3367 /* Fail if this new pattern is a MULT and we didn't have one before
3368 at the outer level. */
3369 || (GET_CODE (newpat
) == SET
&& GET_CODE (SET_SRC (newpat
)) == MULT
3376 /* If the actions of the earlier insns must be kept
3377 in addition to substituting them into the latest one,
3378 we must make a new PARALLEL for the latest insn
3379 to hold additional the SETs. */
3381 if (added_sets_0
|| added_sets_1
|| added_sets_2
)
3383 int extra_sets
= added_sets_0
+ added_sets_1
+ added_sets_2
;
3386 if (GET_CODE (newpat
) == PARALLEL
)
3388 rtvec old
= XVEC (newpat
, 0);
3389 total_sets
= XVECLEN (newpat
, 0) + extra_sets
;
3390 newpat
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (total_sets
));
3391 memcpy (XVEC (newpat
, 0)->elem
, &old
->elem
[0],
3392 sizeof (old
->elem
[0]) * old
->num_elem
);
3397 total_sets
= 1 + extra_sets
;
3398 newpat
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (total_sets
));
3399 XVECEXP (newpat
, 0, 0) = old
;
3403 XVECEXP (newpat
, 0, --total_sets
) = i0pat
;
3409 t
= subst (t
, i0dest
, i0src_copy
? i0src_copy
: i0src
, 0, 0, 0);
3411 XVECEXP (newpat
, 0, --total_sets
) = t
;
3417 t
= subst (t
, i1dest
, i1src_copy
? i1src_copy
: i1src
, 0, 0,
3418 i0_feeds_i1_n
&& i0dest_in_i0src
);
3419 if ((i0_feeds_i1_n
&& i1_feeds_i2_n
) || i0_feeds_i2_n
)
3420 t
= subst (t
, i0dest
, i0src_copy2
? i0src_copy2
: i0src
, 0, 0, 0);
3422 XVECEXP (newpat
, 0, --total_sets
) = t
;
3426 validate_replacement
:
3428 /* Note which hard regs this insn has as inputs. */
3429 mark_used_regs_combine (newpat
);
3431 /* If recog_for_combine fails, it strips existing clobbers. If we'll
3432 consider splitting this pattern, we might need these clobbers. */
3433 if (i1
&& GET_CODE (newpat
) == PARALLEL
3434 && GET_CODE (XVECEXP (newpat
, 0, XVECLEN (newpat
, 0) - 1)) == CLOBBER
)
3436 int len
= XVECLEN (newpat
, 0);
3438 newpat_vec_with_clobbers
= rtvec_alloc (len
);
3439 for (i
= 0; i
< len
; i
++)
3440 RTVEC_ELT (newpat_vec_with_clobbers
, i
) = XVECEXP (newpat
, 0, i
);
3443 /* We have recognized nothing yet. */
3444 insn_code_number
= -1;
3446 /* See if this is a PARALLEL of two SETs where one SET's destination is
3447 a register that is unused and this isn't marked as an instruction that
3448 might trap in an EH region. In that case, we just need the other SET.
3449 We prefer this over the PARALLEL.
3451 This can occur when simplifying a divmod insn. We *must* test for this
3452 case here because the code below that splits two independent SETs doesn't
3453 handle this case correctly when it updates the register status.
3455 It's pointless doing this if we originally had two sets, one from
3456 i3, and one from i2. Combining then splitting the parallel results
3457 in the original i2 again plus an invalid insn (which we delete).
3458 The net effect is only to move instructions around, which makes
3459 debug info less accurate. */
3461 if (!(added_sets_2
&& i1
== 0)
3462 && is_parallel_of_n_reg_sets (newpat
, 2)
3463 && asm_noperands (newpat
) < 0)
3465 rtx set0
= XVECEXP (newpat
, 0, 0);
3466 rtx set1
= XVECEXP (newpat
, 0, 1);
3467 rtx oldpat
= newpat
;
3469 if (((REG_P (SET_DEST (set1
))
3470 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (set1
)))
3471 || (GET_CODE (SET_DEST (set1
)) == SUBREG
3472 && find_reg_note (i3
, REG_UNUSED
, SUBREG_REG (SET_DEST (set1
)))))
3473 && insn_nothrow_p (i3
)
3474 && !side_effects_p (SET_SRC (set1
)))
3477 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3480 else if (((REG_P (SET_DEST (set0
))
3481 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (set0
)))
3482 || (GET_CODE (SET_DEST (set0
)) == SUBREG
3483 && find_reg_note (i3
, REG_UNUSED
,
3484 SUBREG_REG (SET_DEST (set0
)))))
3485 && insn_nothrow_p (i3
)
3486 && !side_effects_p (SET_SRC (set0
)))
3489 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3491 if (insn_code_number
>= 0)
3492 changed_i3_dest
= 1;
3495 if (insn_code_number
< 0)
3499 /* Is the result of combination a valid instruction? */
3500 if (insn_code_number
< 0)
3501 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3503 /* If we were combining three insns and the result is a simple SET
3504 with no ASM_OPERANDS that wasn't recognized, try to split it into two
3505 insns. There are two ways to do this. It can be split using a
3506 machine-specific method (like when you have an addition of a large
3507 constant) or by combine in the function find_split_point. */
3509 if (i1
&& insn_code_number
< 0 && GET_CODE (newpat
) == SET
3510 && asm_noperands (newpat
) < 0)
3512 rtx parallel
, *split
;
3513 rtx_insn
*m_split_insn
;
3515 /* See if the MD file can split NEWPAT. If it can't, see if letting it
3516 use I2DEST as a scratch register will help. In the latter case,
3517 convert I2DEST to the mode of the source of NEWPAT if we can. */
3519 m_split_insn
= combine_split_insns (newpat
, i3
);
3521 /* We can only use I2DEST as a scratch reg if it doesn't overlap any
3522 inputs of NEWPAT. */
3524 /* ??? If I2DEST is not safe, and I1DEST exists, then it would be
3525 possible to try that as a scratch reg. This would require adding
3526 more code to make it work though. */
3528 if (m_split_insn
== 0 && ! reg_overlap_mentioned_p (i2dest
, newpat
))
3530 machine_mode new_mode
= GET_MODE (SET_DEST (newpat
));
3532 /* ??? Reusing i2dest without resetting the reg_stat entry for it
3533 (temporarily, until we are committed to this instruction
3534 combination) does not work: for example, any call to nonzero_bits
3535 on the register (from a splitter in the MD file, for example)
3536 will get the old information, which is invalid.
3538 Since nowadays we can create registers during combine just fine,
3539 we should just create a new one here, not reuse i2dest. */
3541 /* First try to split using the original register as a
3542 scratch register. */
3543 parallel
= gen_rtx_PARALLEL (VOIDmode
,
3544 gen_rtvec (2, newpat
,
3545 gen_rtx_CLOBBER (VOIDmode
,
3547 m_split_insn
= combine_split_insns (parallel
, i3
);
3549 /* If that didn't work, try changing the mode of I2DEST if
3551 if (m_split_insn
== 0
3552 && new_mode
!= GET_MODE (i2dest
)
3553 && new_mode
!= VOIDmode
3554 && can_change_dest_mode (i2dest
, added_sets_2
, new_mode
))
3556 machine_mode old_mode
= GET_MODE (i2dest
);
3559 if (REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
)
3560 ni2dest
= gen_rtx_REG (new_mode
, REGNO (i2dest
));
3563 SUBST_MODE (regno_reg_rtx
[REGNO (i2dest
)], new_mode
);
3564 ni2dest
= regno_reg_rtx
[REGNO (i2dest
)];
3567 parallel
= (gen_rtx_PARALLEL
3569 gen_rtvec (2, newpat
,
3570 gen_rtx_CLOBBER (VOIDmode
,
3572 m_split_insn
= combine_split_insns (parallel
, i3
);
3574 if (m_split_insn
== 0
3575 && REGNO (i2dest
) >= FIRST_PSEUDO_REGISTER
)
3579 adjust_reg_mode (regno_reg_rtx
[REGNO (i2dest
)], old_mode
);
3580 buf
= undobuf
.undos
;
3581 undobuf
.undos
= buf
->next
;
3582 buf
->next
= undobuf
.frees
;
3583 undobuf
.frees
= buf
;
3587 i2scratch
= m_split_insn
!= 0;
3590 /* If recog_for_combine has discarded clobbers, try to use them
3591 again for the split. */
3592 if (m_split_insn
== 0 && newpat_vec_with_clobbers
)
3594 parallel
= gen_rtx_PARALLEL (VOIDmode
, newpat_vec_with_clobbers
);
3595 m_split_insn
= combine_split_insns (parallel
, i3
);
3598 if (m_split_insn
&& NEXT_INSN (m_split_insn
) == NULL_RTX
)
3600 rtx m_split_pat
= PATTERN (m_split_insn
);
3601 insn_code_number
= recog_for_combine (&m_split_pat
, i3
, &new_i3_notes
);
3602 if (insn_code_number
>= 0)
3603 newpat
= m_split_pat
;
3605 else if (m_split_insn
&& NEXT_INSN (NEXT_INSN (m_split_insn
)) == NULL_RTX
3606 && (next_nonnote_nondebug_insn (i2
) == i3
3607 || ! use_crosses_set_p (PATTERN (m_split_insn
), DF_INSN_LUID (i2
))))
3610 rtx newi3pat
= PATTERN (NEXT_INSN (m_split_insn
));
3611 newi2pat
= PATTERN (m_split_insn
);
3613 i3set
= single_set (NEXT_INSN (m_split_insn
));
3614 i2set
= single_set (m_split_insn
);
3616 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3618 /* If I2 or I3 has multiple SETs, we won't know how to track
3619 register status, so don't use these insns. If I2's destination
3620 is used between I2 and I3, we also can't use these insns. */
3622 if (i2_code_number
>= 0 && i2set
&& i3set
3623 && (next_nonnote_nondebug_insn (i2
) == i3
3624 || ! reg_used_between_p (SET_DEST (i2set
), i2
, i3
)))
3625 insn_code_number
= recog_for_combine (&newi3pat
, i3
,
3627 if (insn_code_number
>= 0)
3630 /* It is possible that both insns now set the destination of I3.
3631 If so, we must show an extra use of it. */
3633 if (insn_code_number
>= 0)
3635 rtx new_i3_dest
= SET_DEST (i3set
);
3636 rtx new_i2_dest
= SET_DEST (i2set
);
3638 while (GET_CODE (new_i3_dest
) == ZERO_EXTRACT
3639 || GET_CODE (new_i3_dest
) == STRICT_LOW_PART
3640 || GET_CODE (new_i3_dest
) == SUBREG
)
3641 new_i3_dest
= XEXP (new_i3_dest
, 0);
3643 while (GET_CODE (new_i2_dest
) == ZERO_EXTRACT
3644 || GET_CODE (new_i2_dest
) == STRICT_LOW_PART
3645 || GET_CODE (new_i2_dest
) == SUBREG
)
3646 new_i2_dest
= XEXP (new_i2_dest
, 0);
3648 if (REG_P (new_i3_dest
)
3649 && REG_P (new_i2_dest
)
3650 && REGNO (new_i3_dest
) == REGNO (new_i2_dest
)
3651 && REGNO (new_i2_dest
) < reg_n_sets_max
)
3652 INC_REG_N_SETS (REGNO (new_i2_dest
), 1);
3656 /* If we can split it and use I2DEST, go ahead and see if that
3657 helps things be recognized. Verify that none of the registers
3658 are set between I2 and I3. */
3659 if (insn_code_number
< 0
3660 && (split
= find_split_point (&newpat
, i3
, false)) != 0
3661 && (!HAVE_cc0
|| REG_P (i2dest
))
3662 /* We need I2DEST in the proper mode. If it is a hard register
3663 or the only use of a pseudo, we can change its mode.
3664 Make sure we don't change a hard register to have a mode that
3665 isn't valid for it, or change the number of registers. */
3666 && (GET_MODE (*split
) == GET_MODE (i2dest
)
3667 || GET_MODE (*split
) == VOIDmode
3668 || can_change_dest_mode (i2dest
, added_sets_2
,
3670 && (next_nonnote_nondebug_insn (i2
) == i3
3671 || ! use_crosses_set_p (*split
, DF_INSN_LUID (i2
)))
3672 /* We can't overwrite I2DEST if its value is still used by
3674 && ! reg_referenced_p (i2dest
, newpat
))
3676 rtx newdest
= i2dest
;
3677 enum rtx_code split_code
= GET_CODE (*split
);
3678 machine_mode split_mode
= GET_MODE (*split
);
3679 bool subst_done
= false;
3680 newi2pat
= NULL_RTX
;
3684 /* *SPLIT may be part of I2SRC, so make sure we have the
3685 original expression around for later debug processing.
3686 We should not need I2SRC any more in other cases. */
3687 if (MAY_HAVE_DEBUG_INSNS
)
3688 i2src
= copy_rtx (i2src
);
3692 /* Get NEWDEST as a register in the proper mode. We have already
3693 validated that we can do this. */
3694 if (GET_MODE (i2dest
) != split_mode
&& split_mode
!= VOIDmode
)
3696 if (REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
)
3697 newdest
= gen_rtx_REG (split_mode
, REGNO (i2dest
));
3700 SUBST_MODE (regno_reg_rtx
[REGNO (i2dest
)], split_mode
);
3701 newdest
= regno_reg_rtx
[REGNO (i2dest
)];
3705 /* If *SPLIT is a (mult FOO (const_int pow2)), convert it to
3706 an ASHIFT. This can occur if it was inside a PLUS and hence
3707 appeared to be a memory address. This is a kludge. */
3708 if (split_code
== MULT
3709 && CONST_INT_P (XEXP (*split
, 1))
3710 && INTVAL (XEXP (*split
, 1)) > 0
3711 && (i
= exact_log2 (UINTVAL (XEXP (*split
, 1)))) >= 0)
3713 SUBST (*split
, gen_rtx_ASHIFT (split_mode
,
3714 XEXP (*split
, 0), GEN_INT (i
)));
3715 /* Update split_code because we may not have a multiply
3717 split_code
= GET_CODE (*split
);
3720 /* Similarly for (plus (mult FOO (const_int pow2))). */
3721 if (split_code
== PLUS
3722 && GET_CODE (XEXP (*split
, 0)) == MULT
3723 && CONST_INT_P (XEXP (XEXP (*split
, 0), 1))
3724 && INTVAL (XEXP (XEXP (*split
, 0), 1)) > 0
3725 && (i
= exact_log2 (UINTVAL (XEXP (XEXP (*split
, 0), 1)))) >= 0)
3727 rtx nsplit
= XEXP (*split
, 0);
3728 SUBST (XEXP (*split
, 0), gen_rtx_ASHIFT (GET_MODE (nsplit
),
3729 XEXP (nsplit
, 0), GEN_INT (i
)));
3730 /* Update split_code because we may not have a multiply
3732 split_code
= GET_CODE (*split
);
3735 #ifdef INSN_SCHEDULING
3736 /* If *SPLIT is a paradoxical SUBREG, when we split it, it should
3737 be written as a ZERO_EXTEND. */
3738 if (split_code
== SUBREG
&& MEM_P (SUBREG_REG (*split
)))
3740 /* Or as a SIGN_EXTEND if LOAD_EXTEND_OP says that that's
3741 what it really is. */
3742 if (load_extend_op (GET_MODE (SUBREG_REG (*split
)))
3744 SUBST (*split
, gen_rtx_SIGN_EXTEND (split_mode
,
3745 SUBREG_REG (*split
)));
3747 SUBST (*split
, gen_rtx_ZERO_EXTEND (split_mode
,
3748 SUBREG_REG (*split
)));
3752 /* Attempt to split binary operators using arithmetic identities. */
3753 if (BINARY_P (SET_SRC (newpat
))
3754 && split_mode
== GET_MODE (SET_SRC (newpat
))
3755 && ! side_effects_p (SET_SRC (newpat
)))
3757 rtx setsrc
= SET_SRC (newpat
);
3758 machine_mode mode
= GET_MODE (setsrc
);
3759 enum rtx_code code
= GET_CODE (setsrc
);
3760 rtx src_op0
= XEXP (setsrc
, 0);
3761 rtx src_op1
= XEXP (setsrc
, 1);
3763 /* Split "X = Y op Y" as "Z = Y; X = Z op Z". */
3764 if (rtx_equal_p (src_op0
, src_op1
))
3766 newi2pat
= gen_rtx_SET (newdest
, src_op0
);
3767 SUBST (XEXP (setsrc
, 0), newdest
);
3768 SUBST (XEXP (setsrc
, 1), newdest
);
3771 /* Split "((P op Q) op R) op S" where op is PLUS or MULT. */
3772 else if ((code
== PLUS
|| code
== MULT
)
3773 && GET_CODE (src_op0
) == code
3774 && GET_CODE (XEXP (src_op0
, 0)) == code
3775 && (INTEGRAL_MODE_P (mode
)
3776 || (FLOAT_MODE_P (mode
)
3777 && flag_unsafe_math_optimizations
)))
3779 rtx p
= XEXP (XEXP (src_op0
, 0), 0);
3780 rtx q
= XEXP (XEXP (src_op0
, 0), 1);
3781 rtx r
= XEXP (src_op0
, 1);
3784 /* Split both "((X op Y) op X) op Y" and
3785 "((X op Y) op Y) op X" as "T op T" where T is
3787 if ((rtx_equal_p (p
,r
) && rtx_equal_p (q
,s
))
3788 || (rtx_equal_p (p
,s
) && rtx_equal_p (q
,r
)))
3790 newi2pat
= gen_rtx_SET (newdest
, XEXP (src_op0
, 0));
3791 SUBST (XEXP (setsrc
, 0), newdest
);
3792 SUBST (XEXP (setsrc
, 1), newdest
);
3795 /* Split "((X op X) op Y) op Y)" as "T op T" where
3797 else if (rtx_equal_p (p
,q
) && rtx_equal_p (r
,s
))
3799 rtx tmp
= simplify_gen_binary (code
, mode
, p
, r
);
3800 newi2pat
= gen_rtx_SET (newdest
, tmp
);
3801 SUBST (XEXP (setsrc
, 0), newdest
);
3802 SUBST (XEXP (setsrc
, 1), newdest
);
3810 newi2pat
= gen_rtx_SET (newdest
, *split
);
3811 SUBST (*split
, newdest
);
3814 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3816 /* recog_for_combine might have added CLOBBERs to newi2pat.
3817 Make sure NEWPAT does not depend on the clobbered regs. */
3818 if (GET_CODE (newi2pat
) == PARALLEL
)
3819 for (i
= XVECLEN (newi2pat
, 0) - 1; i
>= 0; i
--)
3820 if (GET_CODE (XVECEXP (newi2pat
, 0, i
)) == CLOBBER
)
3822 rtx reg
= XEXP (XVECEXP (newi2pat
, 0, i
), 0);
3823 if (reg_overlap_mentioned_p (reg
, newpat
))
3830 /* If the split point was a MULT and we didn't have one before,
3831 don't use one now. */
3832 if (i2_code_number
>= 0 && ! (split_code
== MULT
&& ! have_mult
))
3833 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3837 /* Check for a case where we loaded from memory in a narrow mode and
3838 then sign extended it, but we need both registers. In that case,
3839 we have a PARALLEL with both loads from the same memory location.
3840 We can split this into a load from memory followed by a register-register
3841 copy. This saves at least one insn, more if register allocation can
3844 We cannot do this if the destination of the first assignment is a
3845 condition code register or cc0. We eliminate this case by making sure
3846 the SET_DEST and SET_SRC have the same mode.
3848 We cannot do this if the destination of the second assignment is
3849 a register that we have already assumed is zero-extended. Similarly
3850 for a SUBREG of such a register. */
3852 else if (i1
&& insn_code_number
< 0 && asm_noperands (newpat
) < 0
3853 && GET_CODE (newpat
) == PARALLEL
3854 && XVECLEN (newpat
, 0) == 2
3855 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
3856 && GET_CODE (SET_SRC (XVECEXP (newpat
, 0, 0))) == SIGN_EXTEND
3857 && (GET_MODE (SET_DEST (XVECEXP (newpat
, 0, 0)))
3858 == GET_MODE (SET_SRC (XVECEXP (newpat
, 0, 0))))
3859 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
3860 && rtx_equal_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
3861 XEXP (SET_SRC (XVECEXP (newpat
, 0, 0)), 0))
3862 && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
3864 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
3865 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
3866 && ! (temp_expr
= SET_DEST (XVECEXP (newpat
, 0, 1)),
3868 && reg_stat
[REGNO (temp_expr
)].nonzero_bits
!= 0
3869 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < BITS_PER_WORD
3870 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < HOST_BITS_PER_INT
3871 && (reg_stat
[REGNO (temp_expr
)].nonzero_bits
3872 != GET_MODE_MASK (word_mode
))))
3873 && ! (GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) == SUBREG
3874 && (temp_expr
= SUBREG_REG (SET_DEST (XVECEXP (newpat
, 0, 1))),
3876 && reg_stat
[REGNO (temp_expr
)].nonzero_bits
!= 0
3877 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < BITS_PER_WORD
3878 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < HOST_BITS_PER_INT
3879 && (reg_stat
[REGNO (temp_expr
)].nonzero_bits
3880 != GET_MODE_MASK (word_mode
)))))
3881 && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
3882 SET_SRC (XVECEXP (newpat
, 0, 1)))
3883 && ! find_reg_note (i3
, REG_UNUSED
,
3884 SET_DEST (XVECEXP (newpat
, 0, 0))))
3888 newi2pat
= XVECEXP (newpat
, 0, 0);
3889 ni2dest
= SET_DEST (XVECEXP (newpat
, 0, 0));
3890 newpat
= XVECEXP (newpat
, 0, 1);
3891 SUBST (SET_SRC (newpat
),
3892 gen_lowpart (GET_MODE (SET_SRC (newpat
)), ni2dest
));
3893 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3895 if (i2_code_number
>= 0)
3896 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3898 if (insn_code_number
>= 0)
3902 /* Similarly, check for a case where we have a PARALLEL of two independent
3903 SETs but we started with three insns. In this case, we can do the sets
3904 as two separate insns. This case occurs when some SET allows two
3905 other insns to combine, but the destination of that SET is still live.
3907 Also do this if we started with two insns and (at least) one of the
3908 resulting sets is a noop; this noop will be deleted later. */
3910 else if (insn_code_number
< 0 && asm_noperands (newpat
) < 0
3911 && GET_CODE (newpat
) == PARALLEL
3912 && XVECLEN (newpat
, 0) == 2
3913 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
3914 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
3915 && (i1
|| set_noop_p (XVECEXP (newpat
, 0, 0))
3916 || set_noop_p (XVECEXP (newpat
, 0, 1)))
3917 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != ZERO_EXTRACT
3918 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != STRICT_LOW_PART
3919 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
3920 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
3921 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
3922 XVECEXP (newpat
, 0, 0))
3923 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 0)),
3924 XVECEXP (newpat
, 0, 1))
3925 && ! (contains_muldiv (SET_SRC (XVECEXP (newpat
, 0, 0)))
3926 && contains_muldiv (SET_SRC (XVECEXP (newpat
, 0, 1)))))
3928 rtx set0
= XVECEXP (newpat
, 0, 0);
3929 rtx set1
= XVECEXP (newpat
, 0, 1);
3931 /* Normally, it doesn't matter which of the two is done first,
3932 but the one that references cc0 can't be the second, and
3933 one which uses any regs/memory set in between i2 and i3 can't
3934 be first. The PARALLEL might also have been pre-existing in i3,
3935 so we need to make sure that we won't wrongly hoist a SET to i2
3936 that would conflict with a death note present in there. */
3937 if (!use_crosses_set_p (SET_SRC (set1
), DF_INSN_LUID (i2
))
3938 && !(REG_P (SET_DEST (set1
))
3939 && find_reg_note (i2
, REG_DEAD
, SET_DEST (set1
)))
3940 && !(GET_CODE (SET_DEST (set1
)) == SUBREG
3941 && find_reg_note (i2
, REG_DEAD
,
3942 SUBREG_REG (SET_DEST (set1
))))
3943 && (!HAVE_cc0
|| !reg_referenced_p (cc0_rtx
, set0
))
3944 /* If I3 is a jump, ensure that set0 is a jump so that
3945 we do not create invalid RTL. */
3946 && (!JUMP_P (i3
) || SET_DEST (set0
) == pc_rtx
)
3952 else if (!use_crosses_set_p (SET_SRC (set0
), DF_INSN_LUID (i2
))
3953 && !(REG_P (SET_DEST (set0
))
3954 && find_reg_note (i2
, REG_DEAD
, SET_DEST (set0
)))
3955 && !(GET_CODE (SET_DEST (set0
)) == SUBREG
3956 && find_reg_note (i2
, REG_DEAD
,
3957 SUBREG_REG (SET_DEST (set0
))))
3958 && (!HAVE_cc0
|| !reg_referenced_p (cc0_rtx
, set1
))
3959 /* If I3 is a jump, ensure that set1 is a jump so that
3960 we do not create invalid RTL. */
3961 && (!JUMP_P (i3
) || SET_DEST (set1
) == pc_rtx
)
3973 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3975 if (i2_code_number
>= 0)
3977 /* recog_for_combine might have added CLOBBERs to newi2pat.
3978 Make sure NEWPAT does not depend on the clobbered regs. */
3979 if (GET_CODE (newi2pat
) == PARALLEL
)
3981 for (i
= XVECLEN (newi2pat
, 0) - 1; i
>= 0; i
--)
3982 if (GET_CODE (XVECEXP (newi2pat
, 0, i
)) == CLOBBER
)
3984 rtx reg
= XEXP (XVECEXP (newi2pat
, 0, i
), 0);
3985 if (reg_overlap_mentioned_p (reg
, newpat
))
3993 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3997 /* If it still isn't recognized, fail and change things back the way they
3999 if ((insn_code_number
< 0
4000 /* Is the result a reasonable ASM_OPERANDS? */
4001 && (! check_asm_operands (newpat
) || added_sets_1
|| added_sets_2
)))
4007 /* If we had to change another insn, make sure it is valid also. */
4008 if (undobuf
.other_insn
)
4010 CLEAR_HARD_REG_SET (newpat_used_regs
);
4012 other_pat
= PATTERN (undobuf
.other_insn
);
4013 other_code_number
= recog_for_combine (&other_pat
, undobuf
.other_insn
,
4016 if (other_code_number
< 0 && ! check_asm_operands (other_pat
))
4023 /* If I2 is the CC0 setter and I3 is the CC0 user then check whether
4024 they are adjacent to each other or not. */
4027 rtx_insn
*p
= prev_nonnote_insn (i3
);
4028 if (p
&& p
!= i2
&& NONJUMP_INSN_P (p
) && newi2pat
4029 && sets_cc0_p (newi2pat
))
4036 /* Only allow this combination if insn_rtx_costs reports that the
4037 replacement instructions are cheaper than the originals. */
4038 if (!combine_validate_cost (i0
, i1
, i2
, i3
, newpat
, newi2pat
, other_pat
))
4044 if (MAY_HAVE_DEBUG_INSNS
)
4048 for (undo
= undobuf
.undos
; undo
; undo
= undo
->next
)
4049 if (undo
->kind
== UNDO_MODE
)
4051 rtx reg
= *undo
->where
.r
;
4052 machine_mode new_mode
= GET_MODE (reg
);
4053 machine_mode old_mode
= undo
->old_contents
.m
;
4055 /* Temporarily revert mode back. */
4056 adjust_reg_mode (reg
, old_mode
);
4058 if (reg
== i2dest
&& i2scratch
)
4060 /* If we used i2dest as a scratch register with a
4061 different mode, substitute it for the original
4062 i2src while its original mode is temporarily
4063 restored, and then clear i2scratch so that we don't
4064 do it again later. */
4065 propagate_for_debug (i2
, last_combined_insn
, reg
, i2src
,
4068 /* Put back the new mode. */
4069 adjust_reg_mode (reg
, new_mode
);
4073 rtx tempreg
= gen_raw_REG (old_mode
, REGNO (reg
));
4074 rtx_insn
*first
, *last
;
4079 last
= last_combined_insn
;
4084 last
= undobuf
.other_insn
;
4086 if (DF_INSN_LUID (last
)
4087 < DF_INSN_LUID (last_combined_insn
))
4088 last
= last_combined_insn
;
4091 /* We're dealing with a reg that changed mode but not
4092 meaning, so we want to turn it into a subreg for
4093 the new mode. However, because of REG sharing and
4094 because its mode had already changed, we have to do
4095 it in two steps. First, replace any debug uses of
4096 reg, with its original mode temporarily restored,
4097 with this copy we have created; then, replace the
4098 copy with the SUBREG of the original shared reg,
4099 once again changed to the new mode. */
4100 propagate_for_debug (first
, last
, reg
, tempreg
,
4102 adjust_reg_mode (reg
, new_mode
);
4103 propagate_for_debug (first
, last
, tempreg
,
4104 lowpart_subreg (old_mode
, reg
, new_mode
),
4110 /* If we will be able to accept this, we have made a
4111 change to the destination of I3. This requires us to
4112 do a few adjustments. */
4114 if (changed_i3_dest
)
4116 PATTERN (i3
) = newpat
;
4117 adjust_for_new_dest (i3
);
4120 /* We now know that we can do this combination. Merge the insns and
4121 update the status of registers and LOG_LINKS. */
4123 if (undobuf
.other_insn
)
4127 PATTERN (undobuf
.other_insn
) = other_pat
;
4129 /* If any of the notes in OTHER_INSN were REG_DEAD or REG_UNUSED,
4130 ensure that they are still valid. Then add any non-duplicate
4131 notes added by recog_for_combine. */
4132 for (note
= REG_NOTES (undobuf
.other_insn
); note
; note
= next
)
4134 next
= XEXP (note
, 1);
4136 if ((REG_NOTE_KIND (note
) == REG_DEAD
4137 && !reg_referenced_p (XEXP (note
, 0),
4138 PATTERN (undobuf
.other_insn
)))
4139 ||(REG_NOTE_KIND (note
) == REG_UNUSED
4140 && !reg_set_p (XEXP (note
, 0),
4141 PATTERN (undobuf
.other_insn
))))
4142 remove_note (undobuf
.other_insn
, note
);
4145 distribute_notes (new_other_notes
, undobuf
.other_insn
,
4146 undobuf
.other_insn
, NULL
, NULL_RTX
, NULL_RTX
,
4153 struct insn_link
*link
;
4156 /* I3 now uses what used to be its destination and which is now
4157 I2's destination. This requires us to do a few adjustments. */
4158 PATTERN (i3
) = newpat
;
4159 adjust_for_new_dest (i3
);
4161 /* We need a LOG_LINK from I3 to I2. But we used to have one,
4164 However, some later insn might be using I2's dest and have
4165 a LOG_LINK pointing at I3. We must remove this link.
4166 The simplest way to remove the link is to point it at I1,
4167 which we know will be a NOTE. */
4169 /* newi2pat is usually a SET here; however, recog_for_combine might
4170 have added some clobbers. */
4171 if (GET_CODE (newi2pat
) == PARALLEL
)
4172 ni2dest
= SET_DEST (XVECEXP (newi2pat
, 0, 0));
4174 ni2dest
= SET_DEST (newi2pat
);
4176 for (insn
= NEXT_INSN (i3
);
4177 insn
&& (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
4178 || insn
!= BB_HEAD (this_basic_block
->next_bb
));
4179 insn
= NEXT_INSN (insn
))
4181 if (INSN_P (insn
) && reg_referenced_p (ni2dest
, PATTERN (insn
)))
4183 FOR_EACH_LOG_LINK (link
, insn
)
4184 if (link
->insn
== i3
)
4193 rtx i3notes
, i2notes
, i1notes
= 0, i0notes
= 0;
4194 struct insn_link
*i3links
, *i2links
, *i1links
= 0, *i0links
= 0;
4197 /* Compute which registers we expect to eliminate. newi2pat may be setting
4198 either i3dest or i2dest, so we must check it. */
4199 rtx elim_i2
= ((newi2pat
&& reg_set_p (i2dest
, newi2pat
))
4200 || i2dest_in_i2src
|| i2dest_in_i1src
|| i2dest_in_i0src
4203 /* For i1, we need to compute both local elimination and global
4204 elimination information with respect to newi2pat because i1dest
4205 may be the same as i3dest, in which case newi2pat may be setting
4206 i1dest. Global information is used when distributing REG_DEAD
4207 note for i2 and i3, in which case it does matter if newi2pat sets
4210 Local information is used when distributing REG_DEAD note for i1,
4211 in which case it doesn't matter if newi2pat sets i1dest or not.
4212 See PR62151, if we have four insns combination:
4214 i1: r1 <- i1src (using r0)
4216 i2: r0 <- i2src (using r1)
4217 i3: r3 <- i3src (using r0)
4219 From i1's point of view, r0 is eliminated, no matter if it is set
4220 by newi2pat or not. In other words, REG_DEAD info for r0 in i1
4221 should be discarded.
4223 Note local information only affects cases in forms like "I1->I2->I3",
4224 "I0->I1->I2->I3" or "I0&I1->I2, I2->I3". For other cases like
4225 "I0->I1, I1&I2->I3" or "I1&I2->I3", newi2pat won't set i1dest or
4227 rtx local_elim_i1
= (i1
== 0 || i1dest_in_i1src
|| i1dest_in_i0src
4230 rtx elim_i1
= (local_elim_i1
== 0
4231 || (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
4233 /* Same case as i1. */
4234 rtx local_elim_i0
= (i0
== 0 || i0dest_in_i0src
|| !i0dest_killed
4236 rtx elim_i0
= (local_elim_i0
== 0
4237 || (newi2pat
&& reg_set_p (i0dest
, newi2pat
))
4240 /* Get the old REG_NOTES and LOG_LINKS from all our insns and
4242 i3notes
= REG_NOTES (i3
), i3links
= LOG_LINKS (i3
);
4243 i2notes
= REG_NOTES (i2
), i2links
= LOG_LINKS (i2
);
4245 i1notes
= REG_NOTES (i1
), i1links
= LOG_LINKS (i1
);
4247 i0notes
= REG_NOTES (i0
), i0links
= LOG_LINKS (i0
);
4249 /* Ensure that we do not have something that should not be shared but
4250 occurs multiple times in the new insns. Check this by first
4251 resetting all the `used' flags and then copying anything is shared. */
4253 reset_used_flags (i3notes
);
4254 reset_used_flags (i2notes
);
4255 reset_used_flags (i1notes
);
4256 reset_used_flags (i0notes
);
4257 reset_used_flags (newpat
);
4258 reset_used_flags (newi2pat
);
4259 if (undobuf
.other_insn
)
4260 reset_used_flags (PATTERN (undobuf
.other_insn
));
4262 i3notes
= copy_rtx_if_shared (i3notes
);
4263 i2notes
= copy_rtx_if_shared (i2notes
);
4264 i1notes
= copy_rtx_if_shared (i1notes
);
4265 i0notes
= copy_rtx_if_shared (i0notes
);
4266 newpat
= copy_rtx_if_shared (newpat
);
4267 newi2pat
= copy_rtx_if_shared (newi2pat
);
4268 if (undobuf
.other_insn
)
4269 reset_used_flags (PATTERN (undobuf
.other_insn
));
4271 INSN_CODE (i3
) = insn_code_number
;
4272 PATTERN (i3
) = newpat
;
4274 if (CALL_P (i3
) && CALL_INSN_FUNCTION_USAGE (i3
))
4276 rtx call_usage
= CALL_INSN_FUNCTION_USAGE (i3
);
4278 reset_used_flags (call_usage
);
4279 call_usage
= copy_rtx (call_usage
);
4283 /* I2SRC must still be meaningful at this point. Some splitting
4284 operations can invalidate I2SRC, but those operations do not
4287 replace_rtx (call_usage
, i2dest
, i2src
);
4291 replace_rtx (call_usage
, i1dest
, i1src
);
4293 replace_rtx (call_usage
, i0dest
, i0src
);
4295 CALL_INSN_FUNCTION_USAGE (i3
) = call_usage
;
4298 if (undobuf
.other_insn
)
4299 INSN_CODE (undobuf
.other_insn
) = other_code_number
;
4301 /* We had one special case above where I2 had more than one set and
4302 we replaced a destination of one of those sets with the destination
4303 of I3. In that case, we have to update LOG_LINKS of insns later
4304 in this basic block. Note that this (expensive) case is rare.
4306 Also, in this case, we must pretend that all REG_NOTEs for I2
4307 actually came from I3, so that REG_UNUSED notes from I2 will be
4308 properly handled. */
4310 if (i3_subst_into_i2
)
4312 for (i
= 0; i
< XVECLEN (PATTERN (i2
), 0); i
++)
4313 if ((GET_CODE (XVECEXP (PATTERN (i2
), 0, i
)) == SET
4314 || GET_CODE (XVECEXP (PATTERN (i2
), 0, i
)) == CLOBBER
)
4315 && REG_P (SET_DEST (XVECEXP (PATTERN (i2
), 0, i
)))
4316 && SET_DEST (XVECEXP (PATTERN (i2
), 0, i
)) != i2dest
4317 && ! find_reg_note (i2
, REG_UNUSED
,
4318 SET_DEST (XVECEXP (PATTERN (i2
), 0, i
))))
4319 for (temp_insn
= NEXT_INSN (i2
);
4321 && (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
4322 || BB_HEAD (this_basic_block
) != temp_insn
);
4323 temp_insn
= NEXT_INSN (temp_insn
))
4324 if (temp_insn
!= i3
&& INSN_P (temp_insn
))
4325 FOR_EACH_LOG_LINK (link
, temp_insn
)
4326 if (link
->insn
== i2
)
4332 while (XEXP (link
, 1))
4333 link
= XEXP (link
, 1);
4334 XEXP (link
, 1) = i2notes
;
4341 LOG_LINKS (i3
) = NULL
;
4343 LOG_LINKS (i2
) = NULL
;
4348 if (MAY_HAVE_DEBUG_INSNS
&& i2scratch
)
4349 propagate_for_debug (i2
, last_combined_insn
, i2dest
, i2src
,
4351 INSN_CODE (i2
) = i2_code_number
;
4352 PATTERN (i2
) = newi2pat
;
4356 if (MAY_HAVE_DEBUG_INSNS
&& i2src
)
4357 propagate_for_debug (i2
, last_combined_insn
, i2dest
, i2src
,
4359 SET_INSN_DELETED (i2
);
4364 LOG_LINKS (i1
) = NULL
;
4366 if (MAY_HAVE_DEBUG_INSNS
)
4367 propagate_for_debug (i1
, last_combined_insn
, i1dest
, i1src
,
4369 SET_INSN_DELETED (i1
);
4374 LOG_LINKS (i0
) = NULL
;
4376 if (MAY_HAVE_DEBUG_INSNS
)
4377 propagate_for_debug (i0
, last_combined_insn
, i0dest
, i0src
,
4379 SET_INSN_DELETED (i0
);
4382 /* Get death notes for everything that is now used in either I3 or
4383 I2 and used to die in a previous insn. If we built two new
4384 patterns, move from I1 to I2 then I2 to I3 so that we get the
4385 proper movement on registers that I2 modifies. */
4388 from_luid
= DF_INSN_LUID (i0
);
4390 from_luid
= DF_INSN_LUID (i1
);
4392 from_luid
= DF_INSN_LUID (i2
);
4394 move_deaths (newi2pat
, NULL_RTX
, from_luid
, i2
, &midnotes
);
4395 move_deaths (newpat
, newi2pat
, from_luid
, i3
, &midnotes
);
4397 /* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */
4399 distribute_notes (i3notes
, i3
, i3
, newi2pat
? i2
: NULL
,
4400 elim_i2
, elim_i1
, elim_i0
);
4402 distribute_notes (i2notes
, i2
, i3
, newi2pat
? i2
: NULL
,
4403 elim_i2
, elim_i1
, elim_i0
);
4405 distribute_notes (i1notes
, i1
, i3
, newi2pat
? i2
: NULL
,
4406 elim_i2
, local_elim_i1
, local_elim_i0
);
4408 distribute_notes (i0notes
, i0
, i3
, newi2pat
? i2
: NULL
,
4409 elim_i2
, elim_i1
, local_elim_i0
);
4411 distribute_notes (midnotes
, NULL
, i3
, newi2pat
? i2
: NULL
,
4412 elim_i2
, elim_i1
, elim_i0
);
4414 /* Distribute any notes added to I2 or I3 by recog_for_combine. We
4415 know these are REG_UNUSED and want them to go to the desired insn,
4416 so we always pass it as i3. */
4418 if (newi2pat
&& new_i2_notes
)
4419 distribute_notes (new_i2_notes
, i2
, i2
, NULL
, NULL_RTX
, NULL_RTX
,
4423 distribute_notes (new_i3_notes
, i3
, i3
, NULL
, NULL_RTX
, NULL_RTX
,
4426 /* If I3DEST was used in I3SRC, it really died in I3. We may need to
4427 put a REG_DEAD note for it somewhere. If NEWI2PAT exists and sets
4428 I3DEST, the death must be somewhere before I2, not I3. If we passed I3
4429 in that case, it might delete I2. Similarly for I2 and I1.
4430 Show an additional death due to the REG_DEAD note we make here. If
4431 we discard it in distribute_notes, we will decrement it again. */
4435 rtx new_note
= alloc_reg_note (REG_DEAD
, i3dest_killed
, NULL_RTX
);
4436 if (newi2pat
&& reg_set_p (i3dest_killed
, newi2pat
))
4437 distribute_notes (new_note
, NULL
, i2
, NULL
, elim_i2
,
4440 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4441 elim_i2
, elim_i1
, elim_i0
);
4444 if (i2dest_in_i2src
)
4446 rtx new_note
= alloc_reg_note (REG_DEAD
, i2dest
, NULL_RTX
);
4447 if (newi2pat
&& reg_set_p (i2dest
, newi2pat
))
4448 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4449 NULL_RTX
, NULL_RTX
);
4451 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4452 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4455 if (i1dest_in_i1src
)
4457 rtx new_note
= alloc_reg_note (REG_DEAD
, i1dest
, NULL_RTX
);
4458 if (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
4459 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4460 NULL_RTX
, NULL_RTX
);
4462 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4463 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4466 if (i0dest_in_i0src
)
4468 rtx new_note
= alloc_reg_note (REG_DEAD
, i0dest
, NULL_RTX
);
4469 if (newi2pat
&& reg_set_p (i0dest
, newi2pat
))
4470 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4471 NULL_RTX
, NULL_RTX
);
4473 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4474 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4477 distribute_links (i3links
);
4478 distribute_links (i2links
);
4479 distribute_links (i1links
);
4480 distribute_links (i0links
);
4484 struct insn_link
*link
;
4485 rtx_insn
*i2_insn
= 0;
4486 rtx i2_val
= 0, set
;
4488 /* The insn that used to set this register doesn't exist, and
4489 this life of the register may not exist either. See if one of
4490 I3's links points to an insn that sets I2DEST. If it does,
4491 that is now the last known value for I2DEST. If we don't update
4492 this and I2 set the register to a value that depended on its old
4493 contents, we will get confused. If this insn is used, thing
4494 will be set correctly in combine_instructions. */
4495 FOR_EACH_LOG_LINK (link
, i3
)
4496 if ((set
= single_set (link
->insn
)) != 0
4497 && rtx_equal_p (i2dest
, SET_DEST (set
)))
4498 i2_insn
= link
->insn
, i2_val
= SET_SRC (set
);
4500 record_value_for_reg (i2dest
, i2_insn
, i2_val
);
4502 /* If the reg formerly set in I2 died only once and that was in I3,
4503 zero its use count so it won't make `reload' do any work. */
4505 && (newi2pat
== 0 || ! reg_mentioned_p (i2dest
, newi2pat
))
4506 && ! i2dest_in_i2src
4507 && REGNO (i2dest
) < reg_n_sets_max
)
4508 INC_REG_N_SETS (REGNO (i2dest
), -1);
4511 if (i1
&& REG_P (i1dest
))
4513 struct insn_link
*link
;
4514 rtx_insn
*i1_insn
= 0;
4515 rtx i1_val
= 0, set
;
4517 FOR_EACH_LOG_LINK (link
, i3
)
4518 if ((set
= single_set (link
->insn
)) != 0
4519 && rtx_equal_p (i1dest
, SET_DEST (set
)))
4520 i1_insn
= link
->insn
, i1_val
= SET_SRC (set
);
4522 record_value_for_reg (i1dest
, i1_insn
, i1_val
);
4525 && ! i1dest_in_i1src
4526 && REGNO (i1dest
) < reg_n_sets_max
)
4527 INC_REG_N_SETS (REGNO (i1dest
), -1);
4530 if (i0
&& REG_P (i0dest
))
4532 struct insn_link
*link
;
4533 rtx_insn
*i0_insn
= 0;
4534 rtx i0_val
= 0, set
;
4536 FOR_EACH_LOG_LINK (link
, i3
)
4537 if ((set
= single_set (link
->insn
)) != 0
4538 && rtx_equal_p (i0dest
, SET_DEST (set
)))
4539 i0_insn
= link
->insn
, i0_val
= SET_SRC (set
);
4541 record_value_for_reg (i0dest
, i0_insn
, i0_val
);
4544 && ! i0dest_in_i0src
4545 && REGNO (i0dest
) < reg_n_sets_max
)
4546 INC_REG_N_SETS (REGNO (i0dest
), -1);
4549 /* Update reg_stat[].nonzero_bits et al for any changes that may have
4550 been made to this insn. The order is important, because newi2pat
4551 can affect nonzero_bits of newpat. */
4553 note_stores (newi2pat
, set_nonzero_bits_and_sign_copies
, NULL
);
4554 note_stores (newpat
, set_nonzero_bits_and_sign_copies
, NULL
);
4557 if (undobuf
.other_insn
!= NULL_RTX
)
4561 fprintf (dump_file
, "modifying other_insn ");
4562 dump_insn_slim (dump_file
, undobuf
.other_insn
);
4564 df_insn_rescan (undobuf
.other_insn
);
4567 if (i0
&& !(NOTE_P (i0
) && (NOTE_KIND (i0
) == NOTE_INSN_DELETED
)))
4571 fprintf (dump_file
, "modifying insn i0 ");
4572 dump_insn_slim (dump_file
, i0
);
4574 df_insn_rescan (i0
);
4577 if (i1
&& !(NOTE_P (i1
) && (NOTE_KIND (i1
) == NOTE_INSN_DELETED
)))
4581 fprintf (dump_file
, "modifying insn i1 ");
4582 dump_insn_slim (dump_file
, i1
);
4584 df_insn_rescan (i1
);
4587 if (i2
&& !(NOTE_P (i2
) && (NOTE_KIND (i2
) == NOTE_INSN_DELETED
)))
4591 fprintf (dump_file
, "modifying insn i2 ");
4592 dump_insn_slim (dump_file
, i2
);
4594 df_insn_rescan (i2
);
4597 if (i3
&& !(NOTE_P (i3
) && (NOTE_KIND (i3
) == NOTE_INSN_DELETED
)))
4601 fprintf (dump_file
, "modifying insn i3 ");
4602 dump_insn_slim (dump_file
, i3
);
4604 df_insn_rescan (i3
);
4607 /* Set new_direct_jump_p if a new return or simple jump instruction
4608 has been created. Adjust the CFG accordingly. */
4609 if (returnjump_p (i3
) || any_uncondjump_p (i3
))
4611 *new_direct_jump_p
= 1;
4612 mark_jump_label (PATTERN (i3
), i3
, 0);
4613 update_cfg_for_uncondjump (i3
);
4616 if (undobuf
.other_insn
!= NULL_RTX
4617 && (returnjump_p (undobuf
.other_insn
)
4618 || any_uncondjump_p (undobuf
.other_insn
)))
4620 *new_direct_jump_p
= 1;
4621 update_cfg_for_uncondjump (undobuf
.other_insn
);
4624 if (GET_CODE (PATTERN (i3
)) == TRAP_IF
4625 && XEXP (PATTERN (i3
), 0) == const1_rtx
)
4627 basic_block bb
= BLOCK_FOR_INSN (i3
);
4629 remove_edge (split_block (bb
, i3
));
4630 emit_barrier_after_bb (bb
);
4631 *new_direct_jump_p
= 1;
4634 if (undobuf
.other_insn
4635 && GET_CODE (PATTERN (undobuf
.other_insn
)) == TRAP_IF
4636 && XEXP (PATTERN (undobuf
.other_insn
), 0) == const1_rtx
)
4638 basic_block bb
= BLOCK_FOR_INSN (undobuf
.other_insn
);
4640 remove_edge (split_block (bb
, undobuf
.other_insn
));
4641 emit_barrier_after_bb (bb
);
4642 *new_direct_jump_p
= 1;
4645 /* A noop might also need cleaning up of CFG, if it comes from the
4646 simplification of a jump. */
4648 && GET_CODE (newpat
) == SET
4649 && SET_SRC (newpat
) == pc_rtx
4650 && SET_DEST (newpat
) == pc_rtx
)
4652 *new_direct_jump_p
= 1;
4653 update_cfg_for_uncondjump (i3
);
4656 if (undobuf
.other_insn
!= NULL_RTX
4657 && JUMP_P (undobuf
.other_insn
)
4658 && GET_CODE (PATTERN (undobuf
.other_insn
)) == SET
4659 && SET_SRC (PATTERN (undobuf
.other_insn
)) == pc_rtx
4660 && SET_DEST (PATTERN (undobuf
.other_insn
)) == pc_rtx
)
4662 *new_direct_jump_p
= 1;
4663 update_cfg_for_uncondjump (undobuf
.other_insn
);
4666 combine_successes
++;
4669 if (added_links_insn
4670 && (newi2pat
== 0 || DF_INSN_LUID (added_links_insn
) < DF_INSN_LUID (i2
))
4671 && DF_INSN_LUID (added_links_insn
) < DF_INSN_LUID (i3
))
4672 return added_links_insn
;
4674 return newi2pat
? i2
: i3
;
4677 /* Get a marker for undoing to the current state. */
4680 get_undo_marker (void)
4682 return undobuf
.undos
;
4685 /* Undo the modifications up to the marker. */
4688 undo_to_marker (void *marker
)
4690 struct undo
*undo
, *next
;
4692 for (undo
= undobuf
.undos
; undo
!= marker
; undo
= next
)
4700 *undo
->where
.r
= undo
->old_contents
.r
;
4703 *undo
->where
.i
= undo
->old_contents
.i
;
4706 adjust_reg_mode (*undo
->where
.r
, undo
->old_contents
.m
);
4709 *undo
->where
.l
= undo
->old_contents
.l
;
4715 undo
->next
= undobuf
.frees
;
4716 undobuf
.frees
= undo
;
4719 undobuf
.undos
= (struct undo
*) marker
;
4722 /* Undo all the modifications recorded in undobuf. */
4730 /* We've committed to accepting the changes we made. Move all
4731 of the undos to the free list. */
4736 struct undo
*undo
, *next
;
4738 for (undo
= undobuf
.undos
; undo
; undo
= next
)
4741 undo
->next
= undobuf
.frees
;
4742 undobuf
.frees
= undo
;
4747 /* Find the innermost point within the rtx at LOC, possibly LOC itself,
4748 where we have an arithmetic expression and return that point. LOC will
4751 try_combine will call this function to see if an insn can be split into
4755 find_split_point (rtx
*loc
, rtx_insn
*insn
, bool set_src
)
4758 enum rtx_code code
= GET_CODE (x
);
4760 unsigned HOST_WIDE_INT len
= 0;
4761 HOST_WIDE_INT pos
= 0;
4763 rtx inner
= NULL_RTX
;
4765 /* First special-case some codes. */
4769 #ifdef INSN_SCHEDULING
4770 /* If we are making a paradoxical SUBREG invalid, it becomes a split
4772 if (MEM_P (SUBREG_REG (x
)))
4775 return find_split_point (&SUBREG_REG (x
), insn
, false);
4778 /* If we have (mem (const ..)) or (mem (symbol_ref ...)), split it
4779 using LO_SUM and HIGH. */
4780 if (HAVE_lo_sum
&& (GET_CODE (XEXP (x
, 0)) == CONST
4781 || GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
))
4783 machine_mode address_mode
= get_address_mode (x
);
4786 gen_rtx_LO_SUM (address_mode
,
4787 gen_rtx_HIGH (address_mode
, XEXP (x
, 0)),
4789 return &XEXP (XEXP (x
, 0), 0);
4792 /* If we have a PLUS whose second operand is a constant and the
4793 address is not valid, perhaps will can split it up using
4794 the machine-specific way to split large constants. We use
4795 the first pseudo-reg (one of the virtual regs) as a placeholder;
4796 it will not remain in the result. */
4797 if (GET_CODE (XEXP (x
, 0)) == PLUS
4798 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
4799 && ! memory_address_addr_space_p (GET_MODE (x
), XEXP (x
, 0),
4800 MEM_ADDR_SPACE (x
)))
4802 rtx reg
= regno_reg_rtx
[FIRST_PSEUDO_REGISTER
];
4803 rtx_insn
*seq
= combine_split_insns (gen_rtx_SET (reg
, XEXP (x
, 0)),
4806 /* This should have produced two insns, each of which sets our
4807 placeholder. If the source of the second is a valid address,
4808 we can make put both sources together and make a split point
4812 && NEXT_INSN (seq
) != NULL_RTX
4813 && NEXT_INSN (NEXT_INSN (seq
)) == NULL_RTX
4814 && NONJUMP_INSN_P (seq
)
4815 && GET_CODE (PATTERN (seq
)) == SET
4816 && SET_DEST (PATTERN (seq
)) == reg
4817 && ! reg_mentioned_p (reg
,
4818 SET_SRC (PATTERN (seq
)))
4819 && NONJUMP_INSN_P (NEXT_INSN (seq
))
4820 && GET_CODE (PATTERN (NEXT_INSN (seq
))) == SET
4821 && SET_DEST (PATTERN (NEXT_INSN (seq
))) == reg
4822 && memory_address_addr_space_p
4823 (GET_MODE (x
), SET_SRC (PATTERN (NEXT_INSN (seq
))),
4824 MEM_ADDR_SPACE (x
)))
4826 rtx src1
= SET_SRC (PATTERN (seq
));
4827 rtx src2
= SET_SRC (PATTERN (NEXT_INSN (seq
)));
4829 /* Replace the placeholder in SRC2 with SRC1. If we can
4830 find where in SRC2 it was placed, that can become our
4831 split point and we can replace this address with SRC2.
4832 Just try two obvious places. */
4834 src2
= replace_rtx (src2
, reg
, src1
);
4836 if (XEXP (src2
, 0) == src1
)
4837 split
= &XEXP (src2
, 0);
4838 else if (GET_RTX_FORMAT (GET_CODE (XEXP (src2
, 0)))[0] == 'e'
4839 && XEXP (XEXP (src2
, 0), 0) == src1
)
4840 split
= &XEXP (XEXP (src2
, 0), 0);
4844 SUBST (XEXP (x
, 0), src2
);
4849 /* If that didn't work, perhaps the first operand is complex and
4850 needs to be computed separately, so make a split point there.
4851 This will occur on machines that just support REG + CONST
4852 and have a constant moved through some previous computation. */
4854 else if (!OBJECT_P (XEXP (XEXP (x
, 0), 0))
4855 && ! (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SUBREG
4856 && OBJECT_P (SUBREG_REG (XEXP (XEXP (x
, 0), 0)))))
4857 return &XEXP (XEXP (x
, 0), 0);
4860 /* If we have a PLUS whose first operand is complex, try computing it
4861 separately by making a split there. */
4862 if (GET_CODE (XEXP (x
, 0)) == PLUS
4863 && ! memory_address_addr_space_p (GET_MODE (x
), XEXP (x
, 0),
4865 && ! OBJECT_P (XEXP (XEXP (x
, 0), 0))
4866 && ! (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SUBREG
4867 && OBJECT_P (SUBREG_REG (XEXP (XEXP (x
, 0), 0)))))
4868 return &XEXP (XEXP (x
, 0), 0);
4872 /* If SET_DEST is CC0 and SET_SRC is not an operand, a COMPARE, or a
4873 ZERO_EXTRACT, the most likely reason why this doesn't match is that
4874 we need to put the operand into a register. So split at that
4877 if (SET_DEST (x
) == cc0_rtx
4878 && GET_CODE (SET_SRC (x
)) != COMPARE
4879 && GET_CODE (SET_SRC (x
)) != ZERO_EXTRACT
4880 && !OBJECT_P (SET_SRC (x
))
4881 && ! (GET_CODE (SET_SRC (x
)) == SUBREG
4882 && OBJECT_P (SUBREG_REG (SET_SRC (x
)))))
4883 return &SET_SRC (x
);
4885 /* See if we can split SET_SRC as it stands. */
4886 split
= find_split_point (&SET_SRC (x
), insn
, true);
4887 if (split
&& split
!= &SET_SRC (x
))
4890 /* See if we can split SET_DEST as it stands. */
4891 split
= find_split_point (&SET_DEST (x
), insn
, false);
4892 if (split
&& split
!= &SET_DEST (x
))
4895 /* See if this is a bitfield assignment with everything constant. If
4896 so, this is an IOR of an AND, so split it into that. */
4897 if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
4898 && HWI_COMPUTABLE_MODE_P (GET_MODE (XEXP (SET_DEST (x
), 0)))
4899 && CONST_INT_P (XEXP (SET_DEST (x
), 1))
4900 && CONST_INT_P (XEXP (SET_DEST (x
), 2))
4901 && CONST_INT_P (SET_SRC (x
))
4902 && ((INTVAL (XEXP (SET_DEST (x
), 1))
4903 + INTVAL (XEXP (SET_DEST (x
), 2)))
4904 <= GET_MODE_PRECISION (GET_MODE (XEXP (SET_DEST (x
), 0))))
4905 && ! side_effects_p (XEXP (SET_DEST (x
), 0)))
4907 HOST_WIDE_INT pos
= INTVAL (XEXP (SET_DEST (x
), 2));
4908 unsigned HOST_WIDE_INT len
= INTVAL (XEXP (SET_DEST (x
), 1));
4909 unsigned HOST_WIDE_INT src
= INTVAL (SET_SRC (x
));
4910 rtx dest
= XEXP (SET_DEST (x
), 0);
4911 machine_mode mode
= GET_MODE (dest
);
4912 unsigned HOST_WIDE_INT mask
4913 = (HOST_WIDE_INT_1U
<< len
) - 1;
4916 if (BITS_BIG_ENDIAN
)
4917 pos
= GET_MODE_PRECISION (mode
) - len
- pos
;
4919 or_mask
= gen_int_mode (src
<< pos
, mode
);
4922 simplify_gen_binary (IOR
, mode
, dest
, or_mask
));
4925 rtx negmask
= gen_int_mode (~(mask
<< pos
), mode
);
4927 simplify_gen_binary (IOR
, mode
,
4928 simplify_gen_binary (AND
, mode
,
4933 SUBST (SET_DEST (x
), dest
);
4935 split
= find_split_point (&SET_SRC (x
), insn
, true);
4936 if (split
&& split
!= &SET_SRC (x
))
4940 /* Otherwise, see if this is an operation that we can split into two.
4941 If so, try to split that. */
4942 code
= GET_CODE (SET_SRC (x
));
4947 /* If we are AND'ing with a large constant that is only a single
4948 bit and the result is only being used in a context where we
4949 need to know if it is zero or nonzero, replace it with a bit
4950 extraction. This will avoid the large constant, which might
4951 have taken more than one insn to make. If the constant were
4952 not a valid argument to the AND but took only one insn to make,
4953 this is no worse, but if it took more than one insn, it will
4956 if (CONST_INT_P (XEXP (SET_SRC (x
), 1))
4957 && REG_P (XEXP (SET_SRC (x
), 0))
4958 && (pos
= exact_log2 (UINTVAL (XEXP (SET_SRC (x
), 1)))) >= 7
4959 && REG_P (SET_DEST (x
))
4960 && (split
= find_single_use (SET_DEST (x
), insn
, NULL
)) != 0
4961 && (GET_CODE (*split
) == EQ
|| GET_CODE (*split
) == NE
)
4962 && XEXP (*split
, 0) == SET_DEST (x
)
4963 && XEXP (*split
, 1) == const0_rtx
)
4965 rtx extraction
= make_extraction (GET_MODE (SET_DEST (x
)),
4966 XEXP (SET_SRC (x
), 0),
4967 pos
, NULL_RTX
, 1, 1, 0, 0);
4968 if (extraction
!= 0)
4970 SUBST (SET_SRC (x
), extraction
);
4971 return find_split_point (loc
, insn
, false);
4977 /* If STORE_FLAG_VALUE is -1, this is (NE X 0) and only one bit of X
4978 is known to be on, this can be converted into a NEG of a shift. */
4979 if (STORE_FLAG_VALUE
== -1 && XEXP (SET_SRC (x
), 1) == const0_rtx
4980 && GET_MODE (SET_SRC (x
)) == GET_MODE (XEXP (SET_SRC (x
), 0))
4981 && 1 <= (pos
= exact_log2
4982 (nonzero_bits (XEXP (SET_SRC (x
), 0),
4983 GET_MODE (XEXP (SET_SRC (x
), 0))))))
4985 machine_mode mode
= GET_MODE (XEXP (SET_SRC (x
), 0));
4989 gen_rtx_LSHIFTRT (mode
,
4990 XEXP (SET_SRC (x
), 0),
4993 split
= find_split_point (&SET_SRC (x
), insn
, true);
4994 if (split
&& split
!= &SET_SRC (x
))
5000 inner
= XEXP (SET_SRC (x
), 0);
5002 /* We can't optimize if either mode is a partial integer
5003 mode as we don't know how many bits are significant
5005 if (GET_MODE_CLASS (GET_MODE (inner
)) == MODE_PARTIAL_INT
5006 || GET_MODE_CLASS (GET_MODE (SET_SRC (x
))) == MODE_PARTIAL_INT
)
5010 len
= GET_MODE_PRECISION (GET_MODE (inner
));
5016 if (CONST_INT_P (XEXP (SET_SRC (x
), 1))
5017 && CONST_INT_P (XEXP (SET_SRC (x
), 2)))
5019 inner
= XEXP (SET_SRC (x
), 0);
5020 len
= INTVAL (XEXP (SET_SRC (x
), 1));
5021 pos
= INTVAL (XEXP (SET_SRC (x
), 2));
5023 if (BITS_BIG_ENDIAN
)
5024 pos
= GET_MODE_PRECISION (GET_MODE (inner
)) - len
- pos
;
5025 unsignedp
= (code
== ZERO_EXTRACT
);
5034 && pos
+ len
<= GET_MODE_PRECISION (GET_MODE (inner
)))
5036 machine_mode mode
= GET_MODE (SET_SRC (x
));
5038 /* For unsigned, we have a choice of a shift followed by an
5039 AND or two shifts. Use two shifts for field sizes where the
5040 constant might be too large. We assume here that we can
5041 always at least get 8-bit constants in an AND insn, which is
5042 true for every current RISC. */
5044 if (unsignedp
&& len
<= 8)
5046 unsigned HOST_WIDE_INT mask
5047 = (HOST_WIDE_INT_1U
<< len
) - 1;
5051 (mode
, gen_lowpart (mode
, inner
),
5053 gen_int_mode (mask
, mode
)));
5055 split
= find_split_point (&SET_SRC (x
), insn
, true);
5056 if (split
&& split
!= &SET_SRC (x
))
5063 (unsignedp
? LSHIFTRT
: ASHIFTRT
, mode
,
5064 gen_rtx_ASHIFT (mode
,
5065 gen_lowpart (mode
, inner
),
5066 GEN_INT (GET_MODE_PRECISION (mode
)
5068 GEN_INT (GET_MODE_PRECISION (mode
) - len
)));
5070 split
= find_split_point (&SET_SRC (x
), insn
, true);
5071 if (split
&& split
!= &SET_SRC (x
))
5076 /* See if this is a simple operation with a constant as the second
5077 operand. It might be that this constant is out of range and hence
5078 could be used as a split point. */
5079 if (BINARY_P (SET_SRC (x
))
5080 && CONSTANT_P (XEXP (SET_SRC (x
), 1))
5081 && (OBJECT_P (XEXP (SET_SRC (x
), 0))
5082 || (GET_CODE (XEXP (SET_SRC (x
), 0)) == SUBREG
5083 && OBJECT_P (SUBREG_REG (XEXP (SET_SRC (x
), 0))))))
5084 return &XEXP (SET_SRC (x
), 1);
5086 /* Finally, see if this is a simple operation with its first operand
5087 not in a register. The operation might require this operand in a
5088 register, so return it as a split point. We can always do this
5089 because if the first operand were another operation, we would have
5090 already found it as a split point. */
5091 if ((BINARY_P (SET_SRC (x
)) || UNARY_P (SET_SRC (x
)))
5092 && ! register_operand (XEXP (SET_SRC (x
), 0), VOIDmode
))
5093 return &XEXP (SET_SRC (x
), 0);
5099 /* We write NOR as (and (not A) (not B)), but if we don't have a NOR,
5100 it is better to write this as (not (ior A B)) so we can split it.
5101 Similarly for IOR. */
5102 if (GET_CODE (XEXP (x
, 0)) == NOT
&& GET_CODE (XEXP (x
, 1)) == NOT
)
5105 gen_rtx_NOT (GET_MODE (x
),
5106 gen_rtx_fmt_ee (code
== IOR
? AND
: IOR
,
5108 XEXP (XEXP (x
, 0), 0),
5109 XEXP (XEXP (x
, 1), 0))));
5110 return find_split_point (loc
, insn
, set_src
);
5113 /* Many RISC machines have a large set of logical insns. If the
5114 second operand is a NOT, put it first so we will try to split the
5115 other operand first. */
5116 if (GET_CODE (XEXP (x
, 1)) == NOT
)
5118 rtx tem
= XEXP (x
, 0);
5119 SUBST (XEXP (x
, 0), XEXP (x
, 1));
5120 SUBST (XEXP (x
, 1), tem
);
5126 /* Canonicalization can produce (minus A (mult B C)), where C is a
5127 constant. It may be better to try splitting (plus (mult B -C) A)
5128 instead if this isn't a multiply by a power of two. */
5129 if (set_src
&& code
== MINUS
&& GET_CODE (XEXP (x
, 1)) == MULT
5130 && GET_CODE (XEXP (XEXP (x
, 1), 1)) == CONST_INT
5131 && !pow2p_hwi (INTVAL (XEXP (XEXP (x
, 1), 1))))
5133 machine_mode mode
= GET_MODE (x
);
5134 unsigned HOST_WIDE_INT this_int
= INTVAL (XEXP (XEXP (x
, 1), 1));
5135 HOST_WIDE_INT other_int
= trunc_int_for_mode (-this_int
, mode
);
5136 SUBST (*loc
, gen_rtx_PLUS (mode
,
5138 XEXP (XEXP (x
, 1), 0),
5139 gen_int_mode (other_int
,
5142 return find_split_point (loc
, insn
, set_src
);
5145 /* Split at a multiply-accumulate instruction. However if this is
5146 the SET_SRC, we likely do not have such an instruction and it's
5147 worthless to try this split. */
5149 && (GET_CODE (XEXP (x
, 0)) == MULT
5150 || (GET_CODE (XEXP (x
, 0)) == ASHIFT
5151 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)))
5158 /* Otherwise, select our actions depending on our rtx class. */
5159 switch (GET_RTX_CLASS (code
))
5161 case RTX_BITFIELD_OPS
: /* This is ZERO_EXTRACT and SIGN_EXTRACT. */
5163 split
= find_split_point (&XEXP (x
, 2), insn
, false);
5168 case RTX_COMM_ARITH
:
5170 case RTX_COMM_COMPARE
:
5171 split
= find_split_point (&XEXP (x
, 1), insn
, false);
5176 /* Some machines have (and (shift ...) ...) insns. If X is not
5177 an AND, but XEXP (X, 0) is, use it as our split point. */
5178 if (GET_CODE (x
) != AND
&& GET_CODE (XEXP (x
, 0)) == AND
)
5179 return &XEXP (x
, 0);
5181 split
= find_split_point (&XEXP (x
, 0), insn
, false);
5187 /* Otherwise, we don't have a split point. */
5192 /* Throughout X, replace FROM with TO, and return the result.
5193 The result is TO if X is FROM;
5194 otherwise the result is X, but its contents may have been modified.
5195 If they were modified, a record was made in undobuf so that
5196 undo_all will (among other things) return X to its original state.
5198 If the number of changes necessary is too much to record to undo,
5199 the excess changes are not made, so the result is invalid.
5200 The changes already made can still be undone.
5201 undobuf.num_undo is incremented for such changes, so by testing that
5202 the caller can tell whether the result is valid.
5204 `n_occurrences' is incremented each time FROM is replaced.
5206 IN_DEST is nonzero if we are processing the SET_DEST of a SET.
5208 IN_COND is nonzero if we are at the top level of a condition.
5210 UNIQUE_COPY is nonzero if each substitution must be unique. We do this
5211 by copying if `n_occurrences' is nonzero. */
5214 subst (rtx x
, rtx from
, rtx to
, int in_dest
, int in_cond
, int unique_copy
)
5216 enum rtx_code code
= GET_CODE (x
);
5217 machine_mode op0_mode
= VOIDmode
;
5222 /* Two expressions are equal if they are identical copies of a shared
5223 RTX or if they are both registers with the same register number
5226 #define COMBINE_RTX_EQUAL_P(X,Y) \
5228 || (REG_P (X) && REG_P (Y) \
5229 && REGNO (X) == REGNO (Y) && GET_MODE (X) == GET_MODE (Y)))
5231 /* Do not substitute into clobbers of regs -- this will never result in
5233 if (GET_CODE (x
) == CLOBBER
&& REG_P (XEXP (x
, 0)))
5236 if (! in_dest
&& COMBINE_RTX_EQUAL_P (x
, from
))
5239 return (unique_copy
&& n_occurrences
> 1 ? copy_rtx (to
) : to
);
5242 /* If X and FROM are the same register but different modes, they
5243 will not have been seen as equal above. However, the log links code
5244 will make a LOG_LINKS entry for that case. If we do nothing, we
5245 will try to rerecognize our original insn and, when it succeeds,
5246 we will delete the feeding insn, which is incorrect.
5248 So force this insn not to match in this (rare) case. */
5249 if (! in_dest
&& code
== REG
&& REG_P (from
)
5250 && reg_overlap_mentioned_p (x
, from
))
5251 return gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
5253 /* If this is an object, we are done unless it is a MEM or LO_SUM, both
5254 of which may contain things that can be combined. */
5255 if (code
!= MEM
&& code
!= LO_SUM
&& OBJECT_P (x
))
5258 /* It is possible to have a subexpression appear twice in the insn.
5259 Suppose that FROM is a register that appears within TO.
5260 Then, after that subexpression has been scanned once by `subst',
5261 the second time it is scanned, TO may be found. If we were
5262 to scan TO here, we would find FROM within it and create a
5263 self-referent rtl structure which is completely wrong. */
5264 if (COMBINE_RTX_EQUAL_P (x
, to
))
5267 /* Parallel asm_operands need special attention because all of the
5268 inputs are shared across the arms. Furthermore, unsharing the
5269 rtl results in recognition failures. Failure to handle this case
5270 specially can result in circular rtl.
5272 Solve this by doing a normal pass across the first entry of the
5273 parallel, and only processing the SET_DESTs of the subsequent
5276 if (code
== PARALLEL
5277 && GET_CODE (XVECEXP (x
, 0, 0)) == SET
5278 && GET_CODE (SET_SRC (XVECEXP (x
, 0, 0))) == ASM_OPERANDS
)
5280 new_rtx
= subst (XVECEXP (x
, 0, 0), from
, to
, 0, 0, unique_copy
);
5282 /* If this substitution failed, this whole thing fails. */
5283 if (GET_CODE (new_rtx
) == CLOBBER
5284 && XEXP (new_rtx
, 0) == const0_rtx
)
5287 SUBST (XVECEXP (x
, 0, 0), new_rtx
);
5289 for (i
= XVECLEN (x
, 0) - 1; i
>= 1; i
--)
5291 rtx dest
= SET_DEST (XVECEXP (x
, 0, i
));
5294 && GET_CODE (dest
) != CC0
5295 && GET_CODE (dest
) != PC
)
5297 new_rtx
= subst (dest
, from
, to
, 0, 0, unique_copy
);
5299 /* If this substitution failed, this whole thing fails. */
5300 if (GET_CODE (new_rtx
) == CLOBBER
5301 && XEXP (new_rtx
, 0) == const0_rtx
)
5304 SUBST (SET_DEST (XVECEXP (x
, 0, i
)), new_rtx
);
5310 len
= GET_RTX_LENGTH (code
);
5311 fmt
= GET_RTX_FORMAT (code
);
5313 /* We don't need to process a SET_DEST that is a register, CC0,
5314 or PC, so set up to skip this common case. All other cases
5315 where we want to suppress replacing something inside a
5316 SET_SRC are handled via the IN_DEST operand. */
5318 && (REG_P (SET_DEST (x
))
5319 || GET_CODE (SET_DEST (x
)) == CC0
5320 || GET_CODE (SET_DEST (x
)) == PC
))
5323 /* Trying to simplify the operands of a widening MULT is not likely
5324 to create RTL matching a machine insn. */
5326 && (GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
5327 || GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
)
5328 && (GET_CODE (XEXP (x
, 1)) == ZERO_EXTEND
5329 || GET_CODE (XEXP (x
, 1)) == SIGN_EXTEND
)
5330 && REG_P (XEXP (XEXP (x
, 0), 0))
5331 && REG_P (XEXP (XEXP (x
, 1), 0))
5336 /* Get the mode of operand 0 in case X is now a SIGN_EXTEND of a
5339 op0_mode
= GET_MODE (XEXP (x
, 0));
5341 for (i
= 0; i
< len
; i
++)
5346 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
5348 if (COMBINE_RTX_EQUAL_P (XVECEXP (x
, i
, j
), from
))
5350 new_rtx
= (unique_copy
&& n_occurrences
5351 ? copy_rtx (to
) : to
);
5356 new_rtx
= subst (XVECEXP (x
, i
, j
), from
, to
, 0, 0,
5359 /* If this substitution failed, this whole thing
5361 if (GET_CODE (new_rtx
) == CLOBBER
5362 && XEXP (new_rtx
, 0) == const0_rtx
)
5366 SUBST (XVECEXP (x
, i
, j
), new_rtx
);
5369 else if (fmt
[i
] == 'e')
5371 /* If this is a register being set, ignore it. */
5372 new_rtx
= XEXP (x
, i
);
5375 && (((code
== SUBREG
|| code
== ZERO_EXTRACT
)
5377 || code
== STRICT_LOW_PART
))
5380 else if (COMBINE_RTX_EQUAL_P (XEXP (x
, i
), from
))
5382 /* In general, don't install a subreg involving two
5383 modes not tieable. It can worsen register
5384 allocation, and can even make invalid reload
5385 insns, since the reg inside may need to be copied
5386 from in the outside mode, and that may be invalid
5387 if it is an fp reg copied in integer mode.
5389 We allow two exceptions to this: It is valid if
5390 it is inside another SUBREG and the mode of that
5391 SUBREG and the mode of the inside of TO is
5392 tieable and it is valid if X is a SET that copies
5395 if (GET_CODE (to
) == SUBREG
5396 && ! MODES_TIEABLE_P (GET_MODE (to
),
5397 GET_MODE (SUBREG_REG (to
)))
5398 && ! (code
== SUBREG
5399 && MODES_TIEABLE_P (GET_MODE (x
),
5400 GET_MODE (SUBREG_REG (to
))))
5404 && XEXP (x
, 0) == cc0_rtx
))))
5405 return gen_rtx_CLOBBER (VOIDmode
, const0_rtx
);
5409 && REGNO (to
) < FIRST_PSEUDO_REGISTER
5410 && simplify_subreg_regno (REGNO (to
), GET_MODE (to
),
5413 return gen_rtx_CLOBBER (VOIDmode
, const0_rtx
);
5415 new_rtx
= (unique_copy
&& n_occurrences
? copy_rtx (to
) : to
);
5419 /* If we are in a SET_DEST, suppress most cases unless we
5420 have gone inside a MEM, in which case we want to
5421 simplify the address. We assume here that things that
5422 are actually part of the destination have their inner
5423 parts in the first expression. This is true for SUBREG,
5424 STRICT_LOW_PART, and ZERO_EXTRACT, which are the only
5425 things aside from REG and MEM that should appear in a
5427 new_rtx
= subst (XEXP (x
, i
), from
, to
,
5429 && (code
== SUBREG
|| code
== STRICT_LOW_PART
5430 || code
== ZERO_EXTRACT
))
5433 code
== IF_THEN_ELSE
&& i
== 0,
5436 /* If we found that we will have to reject this combination,
5437 indicate that by returning the CLOBBER ourselves, rather than
5438 an expression containing it. This will speed things up as
5439 well as prevent accidents where two CLOBBERs are considered
5440 to be equal, thus producing an incorrect simplification. */
5442 if (GET_CODE (new_rtx
) == CLOBBER
&& XEXP (new_rtx
, 0) == const0_rtx
)
5445 if (GET_CODE (x
) == SUBREG
&& CONST_SCALAR_INT_P (new_rtx
))
5447 machine_mode mode
= GET_MODE (x
);
5449 x
= simplify_subreg (GET_MODE (x
), new_rtx
,
5450 GET_MODE (SUBREG_REG (x
)),
5453 x
= gen_rtx_CLOBBER (mode
, const0_rtx
);
5455 else if (CONST_SCALAR_INT_P (new_rtx
)
5456 && GET_CODE (x
) == ZERO_EXTEND
)
5458 x
= simplify_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
5459 new_rtx
, GET_MODE (XEXP (x
, 0)));
5463 SUBST (XEXP (x
, i
), new_rtx
);
5468 /* Check if we are loading something from the constant pool via float
5469 extension; in this case we would undo compress_float_constant
5470 optimization and degenerate constant load to an immediate value. */
5471 if (GET_CODE (x
) == FLOAT_EXTEND
5472 && MEM_P (XEXP (x
, 0))
5473 && MEM_READONLY_P (XEXP (x
, 0)))
5475 rtx tmp
= avoid_constant_pool_reference (x
);
5480 /* Try to simplify X. If the simplification changed the code, it is likely
5481 that further simplification will help, so loop, but limit the number
5482 of repetitions that will be performed. */
5484 for (i
= 0; i
< 4; i
++)
5486 /* If X is sufficiently simple, don't bother trying to do anything
5488 if (code
!= CONST_INT
&& code
!= REG
&& code
!= CLOBBER
)
5489 x
= combine_simplify_rtx (x
, op0_mode
, in_dest
, in_cond
);
5491 if (GET_CODE (x
) == code
)
5494 code
= GET_CODE (x
);
5496 /* We no longer know the original mode of operand 0 since we
5497 have changed the form of X) */
5498 op0_mode
= VOIDmode
;
5504 /* If X is a commutative operation whose operands are not in the canonical
5505 order, use substitutions to swap them. */
5508 maybe_swap_commutative_operands (rtx x
)
5510 if (COMMUTATIVE_ARITH_P (x
)
5511 && swap_commutative_operands_p (XEXP (x
, 0), XEXP (x
, 1)))
5513 rtx temp
= XEXP (x
, 0);
5514 SUBST (XEXP (x
, 0), XEXP (x
, 1));
5515 SUBST (XEXP (x
, 1), temp
);
5519 /* Simplify X, a piece of RTL. We just operate on the expression at the
5520 outer level; call `subst' to simplify recursively. Return the new
5523 OP0_MODE is the original mode of XEXP (x, 0). IN_DEST is nonzero
5524 if we are inside a SET_DEST. IN_COND is nonzero if we are at the top level
5528 combine_simplify_rtx (rtx x
, machine_mode op0_mode
, int in_dest
,
5531 enum rtx_code code
= GET_CODE (x
);
5532 machine_mode mode
= GET_MODE (x
);
5536 /* If this is a commutative operation, put a constant last and a complex
5537 expression first. We don't need to do this for comparisons here. */
5538 maybe_swap_commutative_operands (x
);
5540 /* Try to fold this expression in case we have constants that weren't
5543 switch (GET_RTX_CLASS (code
))
5546 if (op0_mode
== VOIDmode
)
5547 op0_mode
= GET_MODE (XEXP (x
, 0));
5548 temp
= simplify_unary_operation (code
, mode
, XEXP (x
, 0), op0_mode
);
5551 case RTX_COMM_COMPARE
:
5553 machine_mode cmp_mode
= GET_MODE (XEXP (x
, 0));
5554 if (cmp_mode
== VOIDmode
)
5556 cmp_mode
= GET_MODE (XEXP (x
, 1));
5557 if (cmp_mode
== VOIDmode
)
5558 cmp_mode
= op0_mode
;
5560 temp
= simplify_relational_operation (code
, mode
, cmp_mode
,
5561 XEXP (x
, 0), XEXP (x
, 1));
5564 case RTX_COMM_ARITH
:
5566 temp
= simplify_binary_operation (code
, mode
, XEXP (x
, 0), XEXP (x
, 1));
5568 case RTX_BITFIELD_OPS
:
5570 temp
= simplify_ternary_operation (code
, mode
, op0_mode
, XEXP (x
, 0),
5571 XEXP (x
, 1), XEXP (x
, 2));
5580 code
= GET_CODE (temp
);
5581 op0_mode
= VOIDmode
;
5582 mode
= GET_MODE (temp
);
5585 /* If this is a simple operation applied to an IF_THEN_ELSE, try
5586 applying it to the arms of the IF_THEN_ELSE. This often simplifies
5587 things. Check for cases where both arms are testing the same
5590 Don't do anything if all operands are very simple. */
5593 && ((!OBJECT_P (XEXP (x
, 0))
5594 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5595 && OBJECT_P (SUBREG_REG (XEXP (x
, 0)))))
5596 || (!OBJECT_P (XEXP (x
, 1))
5597 && ! (GET_CODE (XEXP (x
, 1)) == SUBREG
5598 && OBJECT_P (SUBREG_REG (XEXP (x
, 1)))))))
5600 && (!OBJECT_P (XEXP (x
, 0))
5601 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5602 && OBJECT_P (SUBREG_REG (XEXP (x
, 0)))))))
5604 rtx cond
, true_rtx
, false_rtx
;
5605 unsigned HOST_WIDE_INT nz
;
5607 /* If the operation is an AND wrapped in a SIGN_EXTEND or ZERO_EXTEND with
5608 either operand being just a constant single bit value, do nothing since
5609 IF_THEN_ELSE is likely to increase the expression's complexity. */
5610 if (HWI_COMPUTABLE_MODE_P (mode
)
5611 && pow2p_hwi (nz
= nonzero_bits (x
, mode
))
5612 && ! ((code
== SIGN_EXTEND
|| code
== ZERO_EXTEND
)
5613 && GET_CODE (XEXP (x
, 0)) == AND
5614 && CONST_INT_P (XEXP (XEXP (x
, 0), 0))
5615 && UINTVAL (XEXP (XEXP (x
, 0), 0)) == nz
))
5618 cond
= if_then_else_cond (x
, &true_rtx
, &false_rtx
);
5620 /* If everything is a comparison, what we have is highly unlikely
5621 to be simpler, so don't use it. */
5622 && ! (COMPARISON_P (x
)
5623 && (COMPARISON_P (true_rtx
) || COMPARISON_P (false_rtx
))))
5625 rtx cop1
= const0_rtx
;
5626 enum rtx_code cond_code
= simplify_comparison (NE
, &cond
, &cop1
);
5628 if (cond_code
== NE
&& COMPARISON_P (cond
))
5631 /* Simplify the alternative arms; this may collapse the true and
5632 false arms to store-flag values. Be careful to use copy_rtx
5633 here since true_rtx or false_rtx might share RTL with x as a
5634 result of the if_then_else_cond call above. */
5635 true_rtx
= subst (copy_rtx (true_rtx
), pc_rtx
, pc_rtx
, 0, 0, 0);
5636 false_rtx
= subst (copy_rtx (false_rtx
), pc_rtx
, pc_rtx
, 0, 0, 0);
5638 /* If true_rtx and false_rtx are not general_operands, an if_then_else
5639 is unlikely to be simpler. */
5640 if (general_operand (true_rtx
, VOIDmode
)
5641 && general_operand (false_rtx
, VOIDmode
))
5643 enum rtx_code reversed
;
5645 /* Restarting if we generate a store-flag expression will cause
5646 us to loop. Just drop through in this case. */
5648 /* If the result values are STORE_FLAG_VALUE and zero, we can
5649 just make the comparison operation. */
5650 if (true_rtx
== const_true_rtx
&& false_rtx
== const0_rtx
)
5651 x
= simplify_gen_relational (cond_code
, mode
, VOIDmode
,
5653 else if (true_rtx
== const0_rtx
&& false_rtx
== const_true_rtx
5654 && ((reversed
= reversed_comparison_code_parts
5655 (cond_code
, cond
, cop1
, NULL
))
5657 x
= simplify_gen_relational (reversed
, mode
, VOIDmode
,
5660 /* Likewise, we can make the negate of a comparison operation
5661 if the result values are - STORE_FLAG_VALUE and zero. */
5662 else if (CONST_INT_P (true_rtx
)
5663 && INTVAL (true_rtx
) == - STORE_FLAG_VALUE
5664 && false_rtx
== const0_rtx
)
5665 x
= simplify_gen_unary (NEG
, mode
,
5666 simplify_gen_relational (cond_code
,
5670 else if (CONST_INT_P (false_rtx
)
5671 && INTVAL (false_rtx
) == - STORE_FLAG_VALUE
5672 && true_rtx
== const0_rtx
5673 && ((reversed
= reversed_comparison_code_parts
5674 (cond_code
, cond
, cop1
, NULL
))
5676 x
= simplify_gen_unary (NEG
, mode
,
5677 simplify_gen_relational (reversed
,
5682 return gen_rtx_IF_THEN_ELSE (mode
,
5683 simplify_gen_relational (cond_code
,
5688 true_rtx
, false_rtx
);
5690 code
= GET_CODE (x
);
5691 op0_mode
= VOIDmode
;
5696 /* First see if we can apply the inverse distributive law. */
5697 if (code
== PLUS
|| code
== MINUS
5698 || code
== AND
|| code
== IOR
|| code
== XOR
)
5700 x
= apply_distributive_law (x
);
5701 code
= GET_CODE (x
);
5702 op0_mode
= VOIDmode
;
5705 /* If CODE is an associative operation not otherwise handled, see if we
5706 can associate some operands. This can win if they are constants or
5707 if they are logically related (i.e. (a & b) & a). */
5708 if ((code
== PLUS
|| code
== MINUS
|| code
== MULT
|| code
== DIV
5709 || code
== AND
|| code
== IOR
|| code
== XOR
5710 || code
== SMAX
|| code
== SMIN
|| code
== UMAX
|| code
== UMIN
)
5711 && ((INTEGRAL_MODE_P (mode
) && code
!= DIV
)
5712 || (flag_associative_math
&& FLOAT_MODE_P (mode
))))
5714 if (GET_CODE (XEXP (x
, 0)) == code
)
5716 rtx other
= XEXP (XEXP (x
, 0), 0);
5717 rtx inner_op0
= XEXP (XEXP (x
, 0), 1);
5718 rtx inner_op1
= XEXP (x
, 1);
5721 /* Make sure we pass the constant operand if any as the second
5722 one if this is a commutative operation. */
5723 if (CONSTANT_P (inner_op0
) && COMMUTATIVE_ARITH_P (x
))
5724 std::swap (inner_op0
, inner_op1
);
5725 inner
= simplify_binary_operation (code
== MINUS
? PLUS
5726 : code
== DIV
? MULT
5728 mode
, inner_op0
, inner_op1
);
5730 /* For commutative operations, try the other pair if that one
5732 if (inner
== 0 && COMMUTATIVE_ARITH_P (x
))
5734 other
= XEXP (XEXP (x
, 0), 1);
5735 inner
= simplify_binary_operation (code
, mode
,
5736 XEXP (XEXP (x
, 0), 0),
5741 return simplify_gen_binary (code
, mode
, other
, inner
);
5745 /* A little bit of algebraic simplification here. */
5749 /* Ensure that our address has any ASHIFTs converted to MULT in case
5750 address-recognizing predicates are called later. */
5751 temp
= make_compound_operation (XEXP (x
, 0), MEM
);
5752 SUBST (XEXP (x
, 0), temp
);
5756 if (op0_mode
== VOIDmode
)
5757 op0_mode
= GET_MODE (SUBREG_REG (x
));
5759 /* See if this can be moved to simplify_subreg. */
5760 if (CONSTANT_P (SUBREG_REG (x
))
5761 && subreg_lowpart_offset (mode
, op0_mode
) == SUBREG_BYTE (x
)
5762 /* Don't call gen_lowpart if the inner mode
5763 is VOIDmode and we cannot simplify it, as SUBREG without
5764 inner mode is invalid. */
5765 && (GET_MODE (SUBREG_REG (x
)) != VOIDmode
5766 || gen_lowpart_common (mode
, SUBREG_REG (x
))))
5767 return gen_lowpart (mode
, SUBREG_REG (x
));
5769 if (GET_MODE_CLASS (GET_MODE (SUBREG_REG (x
))) == MODE_CC
)
5773 temp
= simplify_subreg (mode
, SUBREG_REG (x
), op0_mode
,
5778 /* If op is known to have all lower bits zero, the result is zero. */
5780 && SCALAR_INT_MODE_P (mode
)
5781 && SCALAR_INT_MODE_P (op0_mode
)
5782 && GET_MODE_PRECISION (mode
) < GET_MODE_PRECISION (op0_mode
)
5783 && subreg_lowpart_offset (mode
, op0_mode
) == SUBREG_BYTE (x
)
5784 && HWI_COMPUTABLE_MODE_P (op0_mode
)
5785 && (nonzero_bits (SUBREG_REG (x
), op0_mode
)
5786 & GET_MODE_MASK (mode
)) == 0)
5787 return CONST0_RTX (mode
);
5790 /* Don't change the mode of the MEM if that would change the meaning
5792 if (MEM_P (SUBREG_REG (x
))
5793 && (MEM_VOLATILE_P (SUBREG_REG (x
))
5794 || mode_dependent_address_p (XEXP (SUBREG_REG (x
), 0),
5795 MEM_ADDR_SPACE (SUBREG_REG (x
)))))
5796 return gen_rtx_CLOBBER (mode
, const0_rtx
);
5798 /* Note that we cannot do any narrowing for non-constants since
5799 we might have been counting on using the fact that some bits were
5800 zero. We now do this in the SET. */
5805 temp
= expand_compound_operation (XEXP (x
, 0));
5807 /* For C equal to the width of MODE minus 1, (neg (ashiftrt X C)) can be
5808 replaced by (lshiftrt X C). This will convert
5809 (neg (sign_extract X 1 Y)) to (zero_extract X 1 Y). */
5811 if (GET_CODE (temp
) == ASHIFTRT
5812 && CONST_INT_P (XEXP (temp
, 1))
5813 && INTVAL (XEXP (temp
, 1)) == GET_MODE_PRECISION (mode
) - 1)
5814 return simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
, XEXP (temp
, 0),
5815 INTVAL (XEXP (temp
, 1)));
5817 /* If X has only a single bit that might be nonzero, say, bit I, convert
5818 (neg X) to (ashiftrt (ashift X C-I) C-I) where C is the bitsize of
5819 MODE minus 1. This will convert (neg (zero_extract X 1 Y)) to
5820 (sign_extract X 1 Y). But only do this if TEMP isn't a register
5821 or a SUBREG of one since we'd be making the expression more
5822 complex if it was just a register. */
5825 && ! (GET_CODE (temp
) == SUBREG
5826 && REG_P (SUBREG_REG (temp
)))
5827 && (i
= exact_log2 (nonzero_bits (temp
, mode
))) >= 0)
5829 rtx temp1
= simplify_shift_const
5830 (NULL_RTX
, ASHIFTRT
, mode
,
5831 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, temp
,
5832 GET_MODE_PRECISION (mode
) - 1 - i
),
5833 GET_MODE_PRECISION (mode
) - 1 - i
);
5835 /* If all we did was surround TEMP with the two shifts, we
5836 haven't improved anything, so don't use it. Otherwise,
5837 we are better off with TEMP1. */
5838 if (GET_CODE (temp1
) != ASHIFTRT
5839 || GET_CODE (XEXP (temp1
, 0)) != ASHIFT
5840 || XEXP (XEXP (temp1
, 0), 0) != temp
)
5846 /* We can't handle truncation to a partial integer mode here
5847 because we don't know the real bitsize of the partial
5849 if (GET_MODE_CLASS (mode
) == MODE_PARTIAL_INT
)
5852 if (HWI_COMPUTABLE_MODE_P (mode
))
5854 force_to_mode (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)),
5855 GET_MODE_MASK (mode
), 0));
5857 /* We can truncate a constant value and return it. */
5858 if (CONST_INT_P (XEXP (x
, 0)))
5859 return gen_int_mode (INTVAL (XEXP (x
, 0)), mode
);
5861 /* Similarly to what we do in simplify-rtx.c, a truncate of a register
5862 whose value is a comparison can be replaced with a subreg if
5863 STORE_FLAG_VALUE permits. */
5864 if (HWI_COMPUTABLE_MODE_P (mode
)
5865 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (mode
)) == 0
5866 && (temp
= get_last_value (XEXP (x
, 0)))
5867 && COMPARISON_P (temp
))
5868 return gen_lowpart (mode
, XEXP (x
, 0));
5872 /* (const (const X)) can become (const X). Do it this way rather than
5873 returning the inner CONST since CONST can be shared with a
5875 if (GET_CODE (XEXP (x
, 0)) == CONST
)
5876 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
5880 /* Convert (lo_sum (high FOO) FOO) to FOO. This is necessary so we
5881 can add in an offset. find_split_point will split this address up
5882 again if it doesn't match. */
5883 if (HAVE_lo_sum
&& GET_CODE (XEXP (x
, 0)) == HIGH
5884 && rtx_equal_p (XEXP (XEXP (x
, 0), 0), XEXP (x
, 1)))
5889 /* (plus (xor (and <foo> (const_int pow2 - 1)) <c>) <-c>)
5890 when c is (const_int (pow2 + 1) / 2) is a sign extension of a
5891 bit-field and can be replaced by either a sign_extend or a
5892 sign_extract. The `and' may be a zero_extend and the two
5893 <c>, -<c> constants may be reversed. */
5894 if (GET_CODE (XEXP (x
, 0)) == XOR
5895 && CONST_INT_P (XEXP (x
, 1))
5896 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
5897 && INTVAL (XEXP (x
, 1)) == -INTVAL (XEXP (XEXP (x
, 0), 1))
5898 && ((i
= exact_log2 (UINTVAL (XEXP (XEXP (x
, 0), 1)))) >= 0
5899 || (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0)
5900 && HWI_COMPUTABLE_MODE_P (mode
)
5901 && ((GET_CODE (XEXP (XEXP (x
, 0), 0)) == AND
5902 && CONST_INT_P (XEXP (XEXP (XEXP (x
, 0), 0), 1))
5903 && (UINTVAL (XEXP (XEXP (XEXP (x
, 0), 0), 1))
5904 == (HOST_WIDE_INT_1U
<< (i
+ 1)) - 1))
5905 || (GET_CODE (XEXP (XEXP (x
, 0), 0)) == ZERO_EXTEND
5906 && (GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)))
5907 == (unsigned int) i
+ 1))))
5908 return simplify_shift_const
5909 (NULL_RTX
, ASHIFTRT
, mode
,
5910 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
5911 XEXP (XEXP (XEXP (x
, 0), 0), 0),
5912 GET_MODE_PRECISION (mode
) - (i
+ 1)),
5913 GET_MODE_PRECISION (mode
) - (i
+ 1));
5915 /* If only the low-order bit of X is possibly nonzero, (plus x -1)
5916 can become (ashiftrt (ashift (xor x 1) C) C) where C is
5917 the bitsize of the mode - 1. This allows simplification of
5918 "a = (b & 8) == 0;" */
5919 if (XEXP (x
, 1) == constm1_rtx
5920 && !REG_P (XEXP (x
, 0))
5921 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5922 && REG_P (SUBREG_REG (XEXP (x
, 0))))
5923 && nonzero_bits (XEXP (x
, 0), mode
) == 1)
5924 return simplify_shift_const (NULL_RTX
, ASHIFTRT
, mode
,
5925 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
5926 gen_rtx_XOR (mode
, XEXP (x
, 0), const1_rtx
),
5927 GET_MODE_PRECISION (mode
) - 1),
5928 GET_MODE_PRECISION (mode
) - 1);
5930 /* If we are adding two things that have no bits in common, convert
5931 the addition into an IOR. This will often be further simplified,
5932 for example in cases like ((a & 1) + (a & 2)), which can
5935 if (HWI_COMPUTABLE_MODE_P (mode
)
5936 && (nonzero_bits (XEXP (x
, 0), mode
)
5937 & nonzero_bits (XEXP (x
, 1), mode
)) == 0)
5939 /* Try to simplify the expression further. */
5940 rtx tor
= simplify_gen_binary (IOR
, mode
, XEXP (x
, 0), XEXP (x
, 1));
5941 temp
= combine_simplify_rtx (tor
, VOIDmode
, in_dest
, 0);
5943 /* If we could, great. If not, do not go ahead with the IOR
5944 replacement, since PLUS appears in many special purpose
5945 address arithmetic instructions. */
5946 if (GET_CODE (temp
) != CLOBBER
5947 && (GET_CODE (temp
) != IOR
5948 || ((XEXP (temp
, 0) != XEXP (x
, 0)
5949 || XEXP (temp
, 1) != XEXP (x
, 1))
5950 && (XEXP (temp
, 0) != XEXP (x
, 1)
5951 || XEXP (temp
, 1) != XEXP (x
, 0)))))
5955 /* Canonicalize x + x into x << 1. */
5956 if (GET_MODE_CLASS (mode
) == MODE_INT
5957 && rtx_equal_p (XEXP (x
, 0), XEXP (x
, 1))
5958 && !side_effects_p (XEXP (x
, 0)))
5959 return simplify_gen_binary (ASHIFT
, mode
, XEXP (x
, 0), const1_rtx
);
5964 /* (minus <foo> (and <foo> (const_int -pow2))) becomes
5965 (and <foo> (const_int pow2-1)) */
5966 if (GET_CODE (XEXP (x
, 1)) == AND
5967 && CONST_INT_P (XEXP (XEXP (x
, 1), 1))
5968 && pow2p_hwi (-UINTVAL (XEXP (XEXP (x
, 1), 1)))
5969 && rtx_equal_p (XEXP (XEXP (x
, 1), 0), XEXP (x
, 0)))
5970 return simplify_and_const_int (NULL_RTX
, mode
, XEXP (x
, 0),
5971 -INTVAL (XEXP (XEXP (x
, 1), 1)) - 1);
5975 /* If we have (mult (plus A B) C), apply the distributive law and then
5976 the inverse distributive law to see if things simplify. This
5977 occurs mostly in addresses, often when unrolling loops. */
5979 if (GET_CODE (XEXP (x
, 0)) == PLUS
)
5981 rtx result
= distribute_and_simplify_rtx (x
, 0);
5986 /* Try simplify a*(b/c) as (a*b)/c. */
5987 if (FLOAT_MODE_P (mode
) && flag_associative_math
5988 && GET_CODE (XEXP (x
, 0)) == DIV
)
5990 rtx tem
= simplify_binary_operation (MULT
, mode
,
5991 XEXP (XEXP (x
, 0), 0),
5994 return simplify_gen_binary (DIV
, mode
, tem
, XEXP (XEXP (x
, 0), 1));
5999 /* If this is a divide by a power of two, treat it as a shift if
6000 its first operand is a shift. */
6001 if (CONST_INT_P (XEXP (x
, 1))
6002 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0
6003 && (GET_CODE (XEXP (x
, 0)) == ASHIFT
6004 || GET_CODE (XEXP (x
, 0)) == LSHIFTRT
6005 || GET_CODE (XEXP (x
, 0)) == ASHIFTRT
6006 || GET_CODE (XEXP (x
, 0)) == ROTATE
6007 || GET_CODE (XEXP (x
, 0)) == ROTATERT
))
6008 return simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
, XEXP (x
, 0), i
);
6012 case GT
: case GTU
: case GE
: case GEU
:
6013 case LT
: case LTU
: case LE
: case LEU
:
6014 case UNEQ
: case LTGT
:
6015 case UNGT
: case UNGE
:
6016 case UNLT
: case UNLE
:
6017 case UNORDERED
: case ORDERED
:
6018 /* If the first operand is a condition code, we can't do anything
6020 if (GET_CODE (XEXP (x
, 0)) == COMPARE
6021 || (GET_MODE_CLASS (GET_MODE (XEXP (x
, 0))) != MODE_CC
6022 && ! CC0_P (XEXP (x
, 0))))
6024 rtx op0
= XEXP (x
, 0);
6025 rtx op1
= XEXP (x
, 1);
6026 enum rtx_code new_code
;
6028 if (GET_CODE (op0
) == COMPARE
)
6029 op1
= XEXP (op0
, 1), op0
= XEXP (op0
, 0);
6031 /* Simplify our comparison, if possible. */
6032 new_code
= simplify_comparison (code
, &op0
, &op1
);
6034 /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X
6035 if only the low-order bit is possibly nonzero in X (such as when
6036 X is a ZERO_EXTRACT of one bit). Similarly, we can convert EQ to
6037 (xor X 1) or (minus 1 X); we use the former. Finally, if X is
6038 known to be either 0 or -1, NE becomes a NEG and EQ becomes
6041 Remove any ZERO_EXTRACT we made when thinking this was a
6042 comparison. It may now be simpler to use, e.g., an AND. If a
6043 ZERO_EXTRACT is indeed appropriate, it will be placed back by
6044 the call to make_compound_operation in the SET case.
6046 Don't apply these optimizations if the caller would
6047 prefer a comparison rather than a value.
6048 E.g., for the condition in an IF_THEN_ELSE most targets need
6049 an explicit comparison. */
6054 else if (STORE_FLAG_VALUE
== 1
6055 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6056 && op1
== const0_rtx
6057 && mode
== GET_MODE (op0
)
6058 && nonzero_bits (op0
, mode
) == 1)
6059 return gen_lowpart (mode
,
6060 expand_compound_operation (op0
));
6062 else if (STORE_FLAG_VALUE
== 1
6063 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6064 && op1
== const0_rtx
6065 && mode
== GET_MODE (op0
)
6066 && (num_sign_bit_copies (op0
, mode
)
6067 == GET_MODE_PRECISION (mode
)))
6069 op0
= expand_compound_operation (op0
);
6070 return simplify_gen_unary (NEG
, mode
,
6071 gen_lowpart (mode
, op0
),
6075 else if (STORE_FLAG_VALUE
== 1
6076 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6077 && op1
== const0_rtx
6078 && mode
== GET_MODE (op0
)
6079 && nonzero_bits (op0
, mode
) == 1)
6081 op0
= expand_compound_operation (op0
);
6082 return simplify_gen_binary (XOR
, mode
,
6083 gen_lowpart (mode
, op0
),
6087 else if (STORE_FLAG_VALUE
== 1
6088 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6089 && op1
== const0_rtx
6090 && mode
== GET_MODE (op0
)
6091 && (num_sign_bit_copies (op0
, mode
)
6092 == GET_MODE_PRECISION (mode
)))
6094 op0
= expand_compound_operation (op0
);
6095 return plus_constant (mode
, gen_lowpart (mode
, op0
), 1);
6098 /* If STORE_FLAG_VALUE is -1, we have cases similar to
6103 else if (STORE_FLAG_VALUE
== -1
6104 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6105 && op1
== const0_rtx
6106 && mode
== GET_MODE (op0
)
6107 && (num_sign_bit_copies (op0
, mode
)
6108 == GET_MODE_PRECISION (mode
)))
6109 return gen_lowpart (mode
,
6110 expand_compound_operation (op0
));
6112 else if (STORE_FLAG_VALUE
== -1
6113 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6114 && op1
== const0_rtx
6115 && mode
== GET_MODE (op0
)
6116 && nonzero_bits (op0
, mode
) == 1)
6118 op0
= expand_compound_operation (op0
);
6119 return simplify_gen_unary (NEG
, mode
,
6120 gen_lowpart (mode
, op0
),
6124 else if (STORE_FLAG_VALUE
== -1
6125 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6126 && op1
== const0_rtx
6127 && mode
== GET_MODE (op0
)
6128 && (num_sign_bit_copies (op0
, mode
)
6129 == GET_MODE_PRECISION (mode
)))
6131 op0
= expand_compound_operation (op0
);
6132 return simplify_gen_unary (NOT
, mode
,
6133 gen_lowpart (mode
, op0
),
6137 /* If X is 0/1, (eq X 0) is X-1. */
6138 else if (STORE_FLAG_VALUE
== -1
6139 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6140 && op1
== const0_rtx
6141 && mode
== GET_MODE (op0
)
6142 && nonzero_bits (op0
, mode
) == 1)
6144 op0
= expand_compound_operation (op0
);
6145 return plus_constant (mode
, gen_lowpart (mode
, op0
), -1);
6148 /* If STORE_FLAG_VALUE says to just test the sign bit and X has just
6149 one bit that might be nonzero, we can convert (ne x 0) to
6150 (ashift x c) where C puts the bit in the sign bit. Remove any
6151 AND with STORE_FLAG_VALUE when we are done, since we are only
6152 going to test the sign bit. */
6153 if (new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6154 && HWI_COMPUTABLE_MODE_P (mode
)
6155 && val_signbit_p (mode
, STORE_FLAG_VALUE
)
6156 && op1
== const0_rtx
6157 && mode
== GET_MODE (op0
)
6158 && (i
= exact_log2 (nonzero_bits (op0
, mode
))) >= 0)
6160 x
= simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
6161 expand_compound_operation (op0
),
6162 GET_MODE_PRECISION (mode
) - 1 - i
);
6163 if (GET_CODE (x
) == AND
&& XEXP (x
, 1) == const_true_rtx
)
6169 /* If the code changed, return a whole new comparison.
6170 We also need to avoid using SUBST in cases where
6171 simplify_comparison has widened a comparison with a CONST_INT,
6172 since in that case the wider CONST_INT may fail the sanity
6173 checks in do_SUBST. */
6174 if (new_code
!= code
6175 || (CONST_INT_P (op1
)
6176 && GET_MODE (op0
) != GET_MODE (XEXP (x
, 0))
6177 && GET_MODE (op0
) != GET_MODE (XEXP (x
, 1))))
6178 return gen_rtx_fmt_ee (new_code
, mode
, op0
, op1
);
6180 /* Otherwise, keep this operation, but maybe change its operands.
6181 This also converts (ne (compare FOO BAR) 0) to (ne FOO BAR). */
6182 SUBST (XEXP (x
, 0), op0
);
6183 SUBST (XEXP (x
, 1), op1
);
6188 return simplify_if_then_else (x
);
6194 /* If we are processing SET_DEST, we are done. */
6198 return expand_compound_operation (x
);
6201 return simplify_set (x
);
6205 return simplify_logical (x
);
6212 /* If this is a shift by a constant amount, simplify it. */
6213 if (CONST_INT_P (XEXP (x
, 1)))
6214 return simplify_shift_const (x
, code
, mode
, XEXP (x
, 0),
6215 INTVAL (XEXP (x
, 1)));
6217 else if (SHIFT_COUNT_TRUNCATED
&& !REG_P (XEXP (x
, 1)))
6219 force_to_mode (XEXP (x
, 1), GET_MODE (XEXP (x
, 1)),
6221 << exact_log2 (GET_MODE_BITSIZE (GET_MODE (x
))))
6233 /* Simplify X, an IF_THEN_ELSE expression. Return the new expression. */
6236 simplify_if_then_else (rtx x
)
6238 machine_mode mode
= GET_MODE (x
);
6239 rtx cond
= XEXP (x
, 0);
6240 rtx true_rtx
= XEXP (x
, 1);
6241 rtx false_rtx
= XEXP (x
, 2);
6242 enum rtx_code true_code
= GET_CODE (cond
);
6243 int comparison_p
= COMPARISON_P (cond
);
6246 enum rtx_code false_code
;
6249 /* Simplify storing of the truth value. */
6250 if (comparison_p
&& true_rtx
== const_true_rtx
&& false_rtx
== const0_rtx
)
6251 return simplify_gen_relational (true_code
, mode
, VOIDmode
,
6252 XEXP (cond
, 0), XEXP (cond
, 1));
6254 /* Also when the truth value has to be reversed. */
6256 && true_rtx
== const0_rtx
&& false_rtx
== const_true_rtx
6257 && (reversed
= reversed_comparison (cond
, mode
)))
6260 /* Sometimes we can simplify the arm of an IF_THEN_ELSE if a register used
6261 in it is being compared against certain values. Get the true and false
6262 comparisons and see if that says anything about the value of each arm. */
6265 && ((false_code
= reversed_comparison_code (cond
, NULL
))
6267 && REG_P (XEXP (cond
, 0)))
6270 rtx from
= XEXP (cond
, 0);
6271 rtx true_val
= XEXP (cond
, 1);
6272 rtx false_val
= true_val
;
6275 /* If FALSE_CODE is EQ, swap the codes and arms. */
6277 if (false_code
== EQ
)
6279 swapped
= 1, true_code
= EQ
, false_code
= NE
;
6280 std::swap (true_rtx
, false_rtx
);
6283 /* If we are comparing against zero and the expression being tested has
6284 only a single bit that might be nonzero, that is its value when it is
6285 not equal to zero. Similarly if it is known to be -1 or 0. */
6287 if (true_code
== EQ
&& true_val
== const0_rtx
6288 && pow2p_hwi (nzb
= nonzero_bits (from
, GET_MODE (from
))))
6291 false_val
= gen_int_mode (nzb
, GET_MODE (from
));
6293 else if (true_code
== EQ
&& true_val
== const0_rtx
6294 && (num_sign_bit_copies (from
, GET_MODE (from
))
6295 == GET_MODE_PRECISION (GET_MODE (from
))))
6298 false_val
= constm1_rtx
;
6301 /* Now simplify an arm if we know the value of the register in the
6302 branch and it is used in the arm. Be careful due to the potential
6303 of locally-shared RTL. */
6305 if (reg_mentioned_p (from
, true_rtx
))
6306 true_rtx
= subst (known_cond (copy_rtx (true_rtx
), true_code
,
6308 pc_rtx
, pc_rtx
, 0, 0, 0);
6309 if (reg_mentioned_p (from
, false_rtx
))
6310 false_rtx
= subst (known_cond (copy_rtx (false_rtx
), false_code
,
6312 pc_rtx
, pc_rtx
, 0, 0, 0);
6314 SUBST (XEXP (x
, 1), swapped
? false_rtx
: true_rtx
);
6315 SUBST (XEXP (x
, 2), swapped
? true_rtx
: false_rtx
);
6317 true_rtx
= XEXP (x
, 1);
6318 false_rtx
= XEXP (x
, 2);
6319 true_code
= GET_CODE (cond
);
6322 /* If we have (if_then_else FOO (pc) (label_ref BAR)) and FOO can be
6323 reversed, do so to avoid needing two sets of patterns for
6324 subtract-and-branch insns. Similarly if we have a constant in the true
6325 arm, the false arm is the same as the first operand of the comparison, or
6326 the false arm is more complicated than the true arm. */
6329 && reversed_comparison_code (cond
, NULL
) != UNKNOWN
6330 && (true_rtx
== pc_rtx
6331 || (CONSTANT_P (true_rtx
)
6332 && !CONST_INT_P (false_rtx
) && false_rtx
!= pc_rtx
)
6333 || true_rtx
== const0_rtx
6334 || (OBJECT_P (true_rtx
) && !OBJECT_P (false_rtx
))
6335 || (GET_CODE (true_rtx
) == SUBREG
&& OBJECT_P (SUBREG_REG (true_rtx
))
6336 && !OBJECT_P (false_rtx
))
6337 || reg_mentioned_p (true_rtx
, false_rtx
)
6338 || rtx_equal_p (false_rtx
, XEXP (cond
, 0))))
6340 true_code
= reversed_comparison_code (cond
, NULL
);
6341 SUBST (XEXP (x
, 0), reversed_comparison (cond
, GET_MODE (cond
)));
6342 SUBST (XEXP (x
, 1), false_rtx
);
6343 SUBST (XEXP (x
, 2), true_rtx
);
6345 std::swap (true_rtx
, false_rtx
);
6348 /* It is possible that the conditional has been simplified out. */
6349 true_code
= GET_CODE (cond
);
6350 comparison_p
= COMPARISON_P (cond
);
6353 /* If the two arms are identical, we don't need the comparison. */
6355 if (rtx_equal_p (true_rtx
, false_rtx
) && ! side_effects_p (cond
))
6358 /* Convert a == b ? b : a to "a". */
6359 if (true_code
== EQ
&& ! side_effects_p (cond
)
6360 && !HONOR_NANS (mode
)
6361 && rtx_equal_p (XEXP (cond
, 0), false_rtx
)
6362 && rtx_equal_p (XEXP (cond
, 1), true_rtx
))
6364 else if (true_code
== NE
&& ! side_effects_p (cond
)
6365 && !HONOR_NANS (mode
)
6366 && rtx_equal_p (XEXP (cond
, 0), true_rtx
)
6367 && rtx_equal_p (XEXP (cond
, 1), false_rtx
))
6370 /* Look for cases where we have (abs x) or (neg (abs X)). */
6372 if (GET_MODE_CLASS (mode
) == MODE_INT
6374 && XEXP (cond
, 1) == const0_rtx
6375 && GET_CODE (false_rtx
) == NEG
6376 && rtx_equal_p (true_rtx
, XEXP (false_rtx
, 0))
6377 && rtx_equal_p (true_rtx
, XEXP (cond
, 0))
6378 && ! side_effects_p (true_rtx
))
6383 return simplify_gen_unary (ABS
, mode
, true_rtx
, mode
);
6387 simplify_gen_unary (NEG
, mode
,
6388 simplify_gen_unary (ABS
, mode
, true_rtx
, mode
),
6394 /* Look for MIN or MAX. */
6396 if ((! FLOAT_MODE_P (mode
) || flag_unsafe_math_optimizations
)
6398 && rtx_equal_p (XEXP (cond
, 0), true_rtx
)
6399 && rtx_equal_p (XEXP (cond
, 1), false_rtx
)
6400 && ! side_effects_p (cond
))
6405 return simplify_gen_binary (SMAX
, mode
, true_rtx
, false_rtx
);
6408 return simplify_gen_binary (SMIN
, mode
, true_rtx
, false_rtx
);
6411 return simplify_gen_binary (UMAX
, mode
, true_rtx
, false_rtx
);
6414 return simplify_gen_binary (UMIN
, mode
, true_rtx
, false_rtx
);
6419 /* If we have (if_then_else COND (OP Z C1) Z) and OP is an identity when its
6420 second operand is zero, this can be done as (OP Z (mult COND C2)) where
6421 C2 = C1 * STORE_FLAG_VALUE. Similarly if OP has an outer ZERO_EXTEND or
6422 SIGN_EXTEND as long as Z is already extended (so we don't destroy it).
6423 We can do this kind of thing in some cases when STORE_FLAG_VALUE is
6424 neither 1 or -1, but it isn't worth checking for. */
6426 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
6428 && GET_MODE_CLASS (mode
) == MODE_INT
6429 && ! side_effects_p (x
))
6431 rtx t
= make_compound_operation (true_rtx
, SET
);
6432 rtx f
= make_compound_operation (false_rtx
, SET
);
6433 rtx cond_op0
= XEXP (cond
, 0);
6434 rtx cond_op1
= XEXP (cond
, 1);
6435 enum rtx_code op
= UNKNOWN
, extend_op
= UNKNOWN
;
6436 machine_mode m
= mode
;
6437 rtx z
= 0, c1
= NULL_RTX
;
6439 if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == MINUS
6440 || GET_CODE (t
) == IOR
|| GET_CODE (t
) == XOR
6441 || GET_CODE (t
) == ASHIFT
6442 || GET_CODE (t
) == LSHIFTRT
|| GET_CODE (t
) == ASHIFTRT
)
6443 && rtx_equal_p (XEXP (t
, 0), f
))
6444 c1
= XEXP (t
, 1), op
= GET_CODE (t
), z
= f
;
6446 /* If an identity-zero op is commutative, check whether there
6447 would be a match if we swapped the operands. */
6448 else if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == IOR
6449 || GET_CODE (t
) == XOR
)
6450 && rtx_equal_p (XEXP (t
, 1), f
))
6451 c1
= XEXP (t
, 0), op
= GET_CODE (t
), z
= f
;
6452 else if (GET_CODE (t
) == SIGN_EXTEND
6453 && (GET_CODE (XEXP (t
, 0)) == PLUS
6454 || GET_CODE (XEXP (t
, 0)) == MINUS
6455 || GET_CODE (XEXP (t
, 0)) == IOR
6456 || GET_CODE (XEXP (t
, 0)) == XOR
6457 || GET_CODE (XEXP (t
, 0)) == ASHIFT
6458 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
6459 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
6460 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
6461 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
6462 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
6463 && (num_sign_bit_copies (f
, GET_MODE (f
))
6465 (GET_MODE_PRECISION (mode
)
6466 - GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (t
, 0), 0))))))
6468 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6469 extend_op
= SIGN_EXTEND
;
6470 m
= GET_MODE (XEXP (t
, 0));
6472 else if (GET_CODE (t
) == SIGN_EXTEND
6473 && (GET_CODE (XEXP (t
, 0)) == PLUS
6474 || GET_CODE (XEXP (t
, 0)) == IOR
6475 || GET_CODE (XEXP (t
, 0)) == XOR
)
6476 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
6477 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
6478 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
6479 && (num_sign_bit_copies (f
, GET_MODE (f
))
6481 (GET_MODE_PRECISION (mode
)
6482 - GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (t
, 0), 1))))))
6484 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6485 extend_op
= SIGN_EXTEND
;
6486 m
= GET_MODE (XEXP (t
, 0));
6488 else if (GET_CODE (t
) == ZERO_EXTEND
6489 && (GET_CODE (XEXP (t
, 0)) == PLUS
6490 || GET_CODE (XEXP (t
, 0)) == MINUS
6491 || GET_CODE (XEXP (t
, 0)) == IOR
6492 || GET_CODE (XEXP (t
, 0)) == XOR
6493 || GET_CODE (XEXP (t
, 0)) == ASHIFT
6494 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
6495 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
6496 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
6497 && HWI_COMPUTABLE_MODE_P (mode
)
6498 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
6499 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
6500 && ((nonzero_bits (f
, GET_MODE (f
))
6501 & ~GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 0))))
6504 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6505 extend_op
= ZERO_EXTEND
;
6506 m
= GET_MODE (XEXP (t
, 0));
6508 else if (GET_CODE (t
) == ZERO_EXTEND
6509 && (GET_CODE (XEXP (t
, 0)) == PLUS
6510 || GET_CODE (XEXP (t
, 0)) == IOR
6511 || GET_CODE (XEXP (t
, 0)) == XOR
)
6512 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
6513 && HWI_COMPUTABLE_MODE_P (mode
)
6514 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
6515 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
6516 && ((nonzero_bits (f
, GET_MODE (f
))
6517 & ~GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 1))))
6520 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6521 extend_op
= ZERO_EXTEND
;
6522 m
= GET_MODE (XEXP (t
, 0));
6527 temp
= subst (simplify_gen_relational (true_code
, m
, VOIDmode
,
6528 cond_op0
, cond_op1
),
6529 pc_rtx
, pc_rtx
, 0, 0, 0);
6530 temp
= simplify_gen_binary (MULT
, m
, temp
,
6531 simplify_gen_binary (MULT
, m
, c1
,
6533 temp
= subst (temp
, pc_rtx
, pc_rtx
, 0, 0, 0);
6534 temp
= simplify_gen_binary (op
, m
, gen_lowpart (m
, z
), temp
);
6536 if (extend_op
!= UNKNOWN
)
6537 temp
= simplify_gen_unary (extend_op
, mode
, temp
, m
);
6543 /* If we have (if_then_else (ne A 0) C1 0) and either A is known to be 0 or
6544 1 and C1 is a single bit or A is known to be 0 or -1 and C1 is the
6545 negation of a single bit, we can convert this operation to a shift. We
6546 can actually do this more generally, but it doesn't seem worth it. */
6548 if (true_code
== NE
&& XEXP (cond
, 1) == const0_rtx
6549 && false_rtx
== const0_rtx
&& CONST_INT_P (true_rtx
)
6550 && ((1 == nonzero_bits (XEXP (cond
, 0), mode
)
6551 && (i
= exact_log2 (UINTVAL (true_rtx
))) >= 0)
6552 || ((num_sign_bit_copies (XEXP (cond
, 0), mode
)
6553 == GET_MODE_PRECISION (mode
))
6554 && (i
= exact_log2 (-UINTVAL (true_rtx
))) >= 0)))
6556 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
6557 gen_lowpart (mode
, XEXP (cond
, 0)), i
);
6559 /* (IF_THEN_ELSE (NE A 0) C1 0) is A or a zero-extend of A if the only
6560 non-zero bit in A is C1. */
6561 if (true_code
== NE
&& XEXP (cond
, 1) == const0_rtx
6562 && false_rtx
== const0_rtx
&& CONST_INT_P (true_rtx
)
6563 && INTEGRAL_MODE_P (GET_MODE (XEXP (cond
, 0)))
6564 && (UINTVAL (true_rtx
) & GET_MODE_MASK (mode
))
6565 == nonzero_bits (XEXP (cond
, 0), GET_MODE (XEXP (cond
, 0)))
6566 && (i
= exact_log2 (UINTVAL (true_rtx
) & GET_MODE_MASK (mode
))) >= 0)
6568 rtx val
= XEXP (cond
, 0);
6569 enum machine_mode val_mode
= GET_MODE (val
);
6570 if (val_mode
== mode
)
6572 else if (GET_MODE_PRECISION (val_mode
) < GET_MODE_PRECISION (mode
))
6573 return simplify_gen_unary (ZERO_EXTEND
, mode
, val
, val_mode
);
6579 /* Simplify X, a SET expression. Return the new expression. */
6582 simplify_set (rtx x
)
6584 rtx src
= SET_SRC (x
);
6585 rtx dest
= SET_DEST (x
);
6587 = GET_MODE (src
) != VOIDmode
? GET_MODE (src
) : GET_MODE (dest
);
6588 rtx_insn
*other_insn
;
6591 /* (set (pc) (return)) gets written as (return). */
6592 if (GET_CODE (dest
) == PC
&& ANY_RETURN_P (src
))
6595 /* Now that we know for sure which bits of SRC we are using, see if we can
6596 simplify the expression for the object knowing that we only need the
6599 if (GET_MODE_CLASS (mode
) == MODE_INT
&& HWI_COMPUTABLE_MODE_P (mode
))
6601 src
= force_to_mode (src
, mode
, HOST_WIDE_INT_M1U
, 0);
6602 SUBST (SET_SRC (x
), src
);
6605 /* If we are setting CC0 or if the source is a COMPARE, look for the use of
6606 the comparison result and try to simplify it unless we already have used
6607 undobuf.other_insn. */
6608 if ((GET_MODE_CLASS (mode
) == MODE_CC
6609 || GET_CODE (src
) == COMPARE
6611 && (cc_use
= find_single_use (dest
, subst_insn
, &other_insn
)) != 0
6612 && (undobuf
.other_insn
== 0 || other_insn
== undobuf
.other_insn
)
6613 && COMPARISON_P (*cc_use
)
6614 && rtx_equal_p (XEXP (*cc_use
, 0), dest
))
6616 enum rtx_code old_code
= GET_CODE (*cc_use
);
6617 enum rtx_code new_code
;
6619 int other_changed
= 0;
6620 rtx inner_compare
= NULL_RTX
;
6621 machine_mode compare_mode
= GET_MODE (dest
);
6623 if (GET_CODE (src
) == COMPARE
)
6625 op0
= XEXP (src
, 0), op1
= XEXP (src
, 1);
6626 if (GET_CODE (op0
) == COMPARE
&& op1
== const0_rtx
)
6628 inner_compare
= op0
;
6629 op0
= XEXP (inner_compare
, 0), op1
= XEXP (inner_compare
, 1);
6633 op0
= src
, op1
= CONST0_RTX (GET_MODE (src
));
6635 tmp
= simplify_relational_operation (old_code
, compare_mode
, VOIDmode
,
6638 new_code
= old_code
;
6639 else if (!CONSTANT_P (tmp
))
6641 new_code
= GET_CODE (tmp
);
6642 op0
= XEXP (tmp
, 0);
6643 op1
= XEXP (tmp
, 1);
6647 rtx pat
= PATTERN (other_insn
);
6648 undobuf
.other_insn
= other_insn
;
6649 SUBST (*cc_use
, tmp
);
6651 /* Attempt to simplify CC user. */
6652 if (GET_CODE (pat
) == SET
)
6654 rtx new_rtx
= simplify_rtx (SET_SRC (pat
));
6655 if (new_rtx
!= NULL_RTX
)
6656 SUBST (SET_SRC (pat
), new_rtx
);
6659 /* Convert X into a no-op move. */
6660 SUBST (SET_DEST (x
), pc_rtx
);
6661 SUBST (SET_SRC (x
), pc_rtx
);
6665 /* Simplify our comparison, if possible. */
6666 new_code
= simplify_comparison (new_code
, &op0
, &op1
);
6668 #ifdef SELECT_CC_MODE
6669 /* If this machine has CC modes other than CCmode, check to see if we
6670 need to use a different CC mode here. */
6671 if (GET_MODE_CLASS (GET_MODE (op0
)) == MODE_CC
)
6672 compare_mode
= GET_MODE (op0
);
6673 else if (inner_compare
6674 && GET_MODE_CLASS (GET_MODE (inner_compare
)) == MODE_CC
6675 && new_code
== old_code
6676 && op0
== XEXP (inner_compare
, 0)
6677 && op1
== XEXP (inner_compare
, 1))
6678 compare_mode
= GET_MODE (inner_compare
);
6680 compare_mode
= SELECT_CC_MODE (new_code
, op0
, op1
);
6682 /* If the mode changed, we have to change SET_DEST, the mode in the
6683 compare, and the mode in the place SET_DEST is used. If SET_DEST is
6684 a hard register, just build new versions with the proper mode. If it
6685 is a pseudo, we lose unless it is only time we set the pseudo, in
6686 which case we can safely change its mode. */
6687 if (!HAVE_cc0
&& compare_mode
!= GET_MODE (dest
))
6689 if (can_change_dest_mode (dest
, 0, compare_mode
))
6691 unsigned int regno
= REGNO (dest
);
6694 if (regno
< FIRST_PSEUDO_REGISTER
)
6695 new_dest
= gen_rtx_REG (compare_mode
, regno
);
6698 SUBST_MODE (regno_reg_rtx
[regno
], compare_mode
);
6699 new_dest
= regno_reg_rtx
[regno
];
6702 SUBST (SET_DEST (x
), new_dest
);
6703 SUBST (XEXP (*cc_use
, 0), new_dest
);
6709 #endif /* SELECT_CC_MODE */
6711 /* If the code changed, we have to build a new comparison in
6712 undobuf.other_insn. */
6713 if (new_code
!= old_code
)
6715 int other_changed_previously
= other_changed
;
6716 unsigned HOST_WIDE_INT mask
;
6717 rtx old_cc_use
= *cc_use
;
6719 SUBST (*cc_use
, gen_rtx_fmt_ee (new_code
, GET_MODE (*cc_use
),
6723 /* If the only change we made was to change an EQ into an NE or
6724 vice versa, OP0 has only one bit that might be nonzero, and OP1
6725 is zero, check if changing the user of the condition code will
6726 produce a valid insn. If it won't, we can keep the original code
6727 in that insn by surrounding our operation with an XOR. */
6729 if (((old_code
== NE
&& new_code
== EQ
)
6730 || (old_code
== EQ
&& new_code
== NE
))
6731 && ! other_changed_previously
&& op1
== const0_rtx
6732 && HWI_COMPUTABLE_MODE_P (GET_MODE (op0
))
6733 && pow2p_hwi (mask
= nonzero_bits (op0
, GET_MODE (op0
))))
6735 rtx pat
= PATTERN (other_insn
), note
= 0;
6737 if ((recog_for_combine (&pat
, other_insn
, ¬e
) < 0
6738 && ! check_asm_operands (pat
)))
6740 *cc_use
= old_cc_use
;
6743 op0
= simplify_gen_binary (XOR
, GET_MODE (op0
), op0
,
6751 undobuf
.other_insn
= other_insn
;
6753 /* Don't generate a compare of a CC with 0, just use that CC. */
6754 if (GET_MODE (op0
) == compare_mode
&& op1
== const0_rtx
)
6756 SUBST (SET_SRC (x
), op0
);
6759 /* Otherwise, if we didn't previously have the same COMPARE we
6760 want, create it from scratch. */
6761 else if (GET_CODE (src
) != COMPARE
|| GET_MODE (src
) != compare_mode
6762 || XEXP (src
, 0) != op0
|| XEXP (src
, 1) != op1
)
6764 SUBST (SET_SRC (x
), gen_rtx_COMPARE (compare_mode
, op0
, op1
));
6770 /* Get SET_SRC in a form where we have placed back any
6771 compound expressions. Then do the checks below. */
6772 src
= make_compound_operation (src
, SET
);
6773 SUBST (SET_SRC (x
), src
);
6776 /* If we have (set x (subreg:m1 (op:m2 ...) 0)) with OP being some operation,
6777 and X being a REG or (subreg (reg)), we may be able to convert this to
6778 (set (subreg:m2 x) (op)).
6780 We can always do this if M1 is narrower than M2 because that means that
6781 we only care about the low bits of the result.
6783 However, on machines without WORD_REGISTER_OPERATIONS defined, we cannot
6784 perform a narrower operation than requested since the high-order bits will
6785 be undefined. On machine where it is defined, this transformation is safe
6786 as long as M1 and M2 have the same number of words. */
6788 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
)
6789 && !OBJECT_P (SUBREG_REG (src
))
6790 && (((GET_MODE_SIZE (GET_MODE (src
)) + (UNITS_PER_WORD
- 1))
6792 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))
6793 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
))
6794 && (WORD_REGISTER_OPERATIONS
6795 || (GET_MODE_SIZE (GET_MODE (src
))
6796 <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))))
6797 #ifdef CANNOT_CHANGE_MODE_CLASS
6798 && ! (REG_P (dest
) && REGNO (dest
) < FIRST_PSEUDO_REGISTER
6799 && REG_CANNOT_CHANGE_MODE_P (REGNO (dest
),
6800 GET_MODE (SUBREG_REG (src
)),
6804 || (GET_CODE (dest
) == SUBREG
6805 && REG_P (SUBREG_REG (dest
)))))
6807 SUBST (SET_DEST (x
),
6808 gen_lowpart (GET_MODE (SUBREG_REG (src
)),
6810 SUBST (SET_SRC (x
), SUBREG_REG (src
));
6812 src
= SET_SRC (x
), dest
= SET_DEST (x
);
6815 /* If we have (set (cc0) (subreg ...)), we try to remove the subreg
6818 && GET_CODE (src
) == SUBREG
6819 && subreg_lowpart_p (src
)
6820 && (GET_MODE_PRECISION (GET_MODE (src
))
6821 < GET_MODE_PRECISION (GET_MODE (SUBREG_REG (src
)))))
6823 rtx inner
= SUBREG_REG (src
);
6824 machine_mode inner_mode
= GET_MODE (inner
);
6826 /* Here we make sure that we don't have a sign bit on. */
6827 if (val_signbit_known_clear_p (GET_MODE (src
),
6828 nonzero_bits (inner
, inner_mode
)))
6830 SUBST (SET_SRC (x
), inner
);
6835 /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with M wider than N, this
6836 would require a paradoxical subreg. Replace the subreg with a
6837 zero_extend to avoid the reload that would otherwise be required. */
6839 enum rtx_code extend_op
;
6840 if (paradoxical_subreg_p (src
)
6841 && MEM_P (SUBREG_REG (src
))
6842 && (extend_op
= load_extend_op (GET_MODE (SUBREG_REG (src
)))) != UNKNOWN
)
6845 gen_rtx_fmt_e (extend_op
, GET_MODE (src
), SUBREG_REG (src
)));
6850 /* If we don't have a conditional move, SET_SRC is an IF_THEN_ELSE, and we
6851 are comparing an item known to be 0 or -1 against 0, use a logical
6852 operation instead. Check for one of the arms being an IOR of the other
6853 arm with some value. We compute three terms to be IOR'ed together. In
6854 practice, at most two will be nonzero. Then we do the IOR's. */
6856 if (GET_CODE (dest
) != PC
6857 && GET_CODE (src
) == IF_THEN_ELSE
6858 && GET_MODE_CLASS (GET_MODE (src
)) == MODE_INT
6859 && (GET_CODE (XEXP (src
, 0)) == EQ
|| GET_CODE (XEXP (src
, 0)) == NE
)
6860 && XEXP (XEXP (src
, 0), 1) == const0_rtx
6861 && GET_MODE (src
) == GET_MODE (XEXP (XEXP (src
, 0), 0))
6862 && (!HAVE_conditional_move
6863 || ! can_conditionally_move_p (GET_MODE (src
)))
6864 && (num_sign_bit_copies (XEXP (XEXP (src
, 0), 0),
6865 GET_MODE (XEXP (XEXP (src
, 0), 0)))
6866 == GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (src
, 0), 0))))
6867 && ! side_effects_p (src
))
6869 rtx true_rtx
= (GET_CODE (XEXP (src
, 0)) == NE
6870 ? XEXP (src
, 1) : XEXP (src
, 2));
6871 rtx false_rtx
= (GET_CODE (XEXP (src
, 0)) == NE
6872 ? XEXP (src
, 2) : XEXP (src
, 1));
6873 rtx term1
= const0_rtx
, term2
, term3
;
6875 if (GET_CODE (true_rtx
) == IOR
6876 && rtx_equal_p (XEXP (true_rtx
, 0), false_rtx
))
6877 term1
= false_rtx
, true_rtx
= XEXP (true_rtx
, 1), false_rtx
= const0_rtx
;
6878 else if (GET_CODE (true_rtx
) == IOR
6879 && rtx_equal_p (XEXP (true_rtx
, 1), false_rtx
))
6880 term1
= false_rtx
, true_rtx
= XEXP (true_rtx
, 0), false_rtx
= const0_rtx
;
6881 else if (GET_CODE (false_rtx
) == IOR
6882 && rtx_equal_p (XEXP (false_rtx
, 0), true_rtx
))
6883 term1
= true_rtx
, false_rtx
= XEXP (false_rtx
, 1), true_rtx
= const0_rtx
;
6884 else if (GET_CODE (false_rtx
) == IOR
6885 && rtx_equal_p (XEXP (false_rtx
, 1), true_rtx
))
6886 term1
= true_rtx
, false_rtx
= XEXP (false_rtx
, 0), true_rtx
= const0_rtx
;
6888 term2
= simplify_gen_binary (AND
, GET_MODE (src
),
6889 XEXP (XEXP (src
, 0), 0), true_rtx
);
6890 term3
= simplify_gen_binary (AND
, GET_MODE (src
),
6891 simplify_gen_unary (NOT
, GET_MODE (src
),
6892 XEXP (XEXP (src
, 0), 0),
6897 simplify_gen_binary (IOR
, GET_MODE (src
),
6898 simplify_gen_binary (IOR
, GET_MODE (src
),
6905 /* If either SRC or DEST is a CLOBBER of (const_int 0), make this
6906 whole thing fail. */
6907 if (GET_CODE (src
) == CLOBBER
&& XEXP (src
, 0) == const0_rtx
)
6909 else if (GET_CODE (dest
) == CLOBBER
&& XEXP (dest
, 0) == const0_rtx
)
6912 /* Convert this into a field assignment operation, if possible. */
6913 return make_field_assignment (x
);
6916 /* Simplify, X, and AND, IOR, or XOR operation, and return the simplified
6920 simplify_logical (rtx x
)
6922 machine_mode mode
= GET_MODE (x
);
6923 rtx op0
= XEXP (x
, 0);
6924 rtx op1
= XEXP (x
, 1);
6926 switch (GET_CODE (x
))
6929 /* We can call simplify_and_const_int only if we don't lose
6930 any (sign) bits when converting INTVAL (op1) to
6931 "unsigned HOST_WIDE_INT". */
6932 if (CONST_INT_P (op1
)
6933 && (HWI_COMPUTABLE_MODE_P (mode
)
6934 || INTVAL (op1
) > 0))
6936 x
= simplify_and_const_int (x
, mode
, op0
, INTVAL (op1
));
6937 if (GET_CODE (x
) != AND
)
6944 /* If we have any of (and (ior A B) C) or (and (xor A B) C),
6945 apply the distributive law and then the inverse distributive
6946 law to see if things simplify. */
6947 if (GET_CODE (op0
) == IOR
|| GET_CODE (op0
) == XOR
)
6949 rtx result
= distribute_and_simplify_rtx (x
, 0);
6953 if (GET_CODE (op1
) == IOR
|| GET_CODE (op1
) == XOR
)
6955 rtx result
= distribute_and_simplify_rtx (x
, 1);
6962 /* If we have (ior (and A B) C), apply the distributive law and then
6963 the inverse distributive law to see if things simplify. */
6965 if (GET_CODE (op0
) == AND
)
6967 rtx result
= distribute_and_simplify_rtx (x
, 0);
6972 if (GET_CODE (op1
) == AND
)
6974 rtx result
= distribute_and_simplify_rtx (x
, 1);
6987 /* We consider ZERO_EXTRACT, SIGN_EXTRACT, and SIGN_EXTEND as "compound
6988 operations" because they can be replaced with two more basic operations.
6989 ZERO_EXTEND is also considered "compound" because it can be replaced with
6990 an AND operation, which is simpler, though only one operation.
6992 The function expand_compound_operation is called with an rtx expression
6993 and will convert it to the appropriate shifts and AND operations,
6994 simplifying at each stage.
6996 The function make_compound_operation is called to convert an expression
6997 consisting of shifts and ANDs into the equivalent compound expression.
6998 It is the inverse of this function, loosely speaking. */
7001 expand_compound_operation (rtx x
)
7003 unsigned HOST_WIDE_INT pos
= 0, len
;
7005 unsigned int modewidth
;
7008 switch (GET_CODE (x
))
7014 /* We can't necessarily use a const_int for a multiword mode;
7015 it depends on implicitly extending the value.
7016 Since we don't know the right way to extend it,
7017 we can't tell whether the implicit way is right.
7019 Even for a mode that is no wider than a const_int,
7020 we can't win, because we need to sign extend one of its bits through
7021 the rest of it, and we don't know which bit. */
7022 if (CONST_INT_P (XEXP (x
, 0)))
7025 /* Return if (subreg:MODE FROM 0) is not a safe replacement for
7026 (zero_extend:MODE FROM) or (sign_extend:MODE FROM). It is for any MEM
7027 because (SUBREG (MEM...)) is guaranteed to cause the MEM to be
7028 reloaded. If not for that, MEM's would very rarely be safe.
7030 Reject MODEs bigger than a word, because we might not be able
7031 to reference a two-register group starting with an arbitrary register
7032 (and currently gen_lowpart might crash for a SUBREG). */
7034 if (GET_MODE_SIZE (GET_MODE (XEXP (x
, 0))) > UNITS_PER_WORD
)
7037 /* Reject MODEs that aren't scalar integers because turning vector
7038 or complex modes into shifts causes problems. */
7040 if (! SCALAR_INT_MODE_P (GET_MODE (XEXP (x
, 0))))
7043 len
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)));
7044 /* If the inner object has VOIDmode (the only way this can happen
7045 is if it is an ASM_OPERANDS), we can't do anything since we don't
7046 know how much masking to do. */
7058 /* If the operand is a CLOBBER, just return it. */
7059 if (GET_CODE (XEXP (x
, 0)) == CLOBBER
)
7062 if (!CONST_INT_P (XEXP (x
, 1))
7063 || !CONST_INT_P (XEXP (x
, 2))
7064 || GET_MODE (XEXP (x
, 0)) == VOIDmode
)
7067 /* Reject MODEs that aren't scalar integers because turning vector
7068 or complex modes into shifts causes problems. */
7070 if (! SCALAR_INT_MODE_P (GET_MODE (XEXP (x
, 0))))
7073 len
= INTVAL (XEXP (x
, 1));
7074 pos
= INTVAL (XEXP (x
, 2));
7076 /* This should stay within the object being extracted, fail otherwise. */
7077 if (len
+ pos
> GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0))))
7080 if (BITS_BIG_ENDIAN
)
7081 pos
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0))) - len
- pos
;
7088 /* Convert sign extension to zero extension, if we know that the high
7089 bit is not set, as this is easier to optimize. It will be converted
7090 back to cheaper alternative in make_extraction. */
7091 if (GET_CODE (x
) == SIGN_EXTEND
7092 && (HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7093 && ((nonzero_bits (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
7094 & ~(((unsigned HOST_WIDE_INT
)
7095 GET_MODE_MASK (GET_MODE (XEXP (x
, 0))))
7099 machine_mode mode
= GET_MODE (x
);
7100 rtx temp
= gen_rtx_ZERO_EXTEND (mode
, XEXP (x
, 0));
7101 rtx temp2
= expand_compound_operation (temp
);
7103 /* Make sure this is a profitable operation. */
7104 if (set_src_cost (x
, mode
, optimize_this_for_speed_p
)
7105 > set_src_cost (temp2
, mode
, optimize_this_for_speed_p
))
7107 else if (set_src_cost (x
, mode
, optimize_this_for_speed_p
)
7108 > set_src_cost (temp
, mode
, optimize_this_for_speed_p
))
7114 /* We can optimize some special cases of ZERO_EXTEND. */
7115 if (GET_CODE (x
) == ZERO_EXTEND
)
7117 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI if we
7118 know that the last value didn't have any inappropriate bits
7120 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
7121 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
7122 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7123 && (nonzero_bits (XEXP (XEXP (x
, 0), 0), GET_MODE (x
))
7124 & ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7125 return XEXP (XEXP (x
, 0), 0);
7127 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
7128 if (GET_CODE (XEXP (x
, 0)) == SUBREG
7129 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
7130 && subreg_lowpart_p (XEXP (x
, 0))
7131 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7132 && (nonzero_bits (SUBREG_REG (XEXP (x
, 0)), GET_MODE (x
))
7133 & ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7134 return SUBREG_REG (XEXP (x
, 0));
7136 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI when foo
7137 is a comparison and STORE_FLAG_VALUE permits. This is like
7138 the first case, but it works even when GET_MODE (x) is larger
7139 than HOST_WIDE_INT. */
7140 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
7141 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
7142 && COMPARISON_P (XEXP (XEXP (x
, 0), 0))
7143 && (GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)))
7144 <= HOST_BITS_PER_WIDE_INT
)
7145 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7146 return XEXP (XEXP (x
, 0), 0);
7148 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
7149 if (GET_CODE (XEXP (x
, 0)) == SUBREG
7150 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
7151 && subreg_lowpart_p (XEXP (x
, 0))
7152 && COMPARISON_P (SUBREG_REG (XEXP (x
, 0)))
7153 && (GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)))
7154 <= HOST_BITS_PER_WIDE_INT
)
7155 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7156 return SUBREG_REG (XEXP (x
, 0));
7160 /* If we reach here, we want to return a pair of shifts. The inner
7161 shift is a left shift of BITSIZE - POS - LEN bits. The outer
7162 shift is a right shift of BITSIZE - LEN bits. It is arithmetic or
7163 logical depending on the value of UNSIGNEDP.
7165 If this was a ZERO_EXTEND or ZERO_EXTRACT, this pair of shifts will be
7166 converted into an AND of a shift.
7168 We must check for the case where the left shift would have a negative
7169 count. This can happen in a case like (x >> 31) & 255 on machines
7170 that can't shift by a constant. On those machines, we would first
7171 combine the shift with the AND to produce a variable-position
7172 extraction. Then the constant of 31 would be substituted in
7173 to produce such a position. */
7175 modewidth
= GET_MODE_PRECISION (GET_MODE (x
));
7176 if (modewidth
>= pos
+ len
)
7178 machine_mode mode
= GET_MODE (x
);
7179 tem
= gen_lowpart (mode
, XEXP (x
, 0));
7180 if (!tem
|| GET_CODE (tem
) == CLOBBER
)
7182 tem
= simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
7183 tem
, modewidth
- pos
- len
);
7184 tem
= simplify_shift_const (NULL_RTX
, unsignedp
? LSHIFTRT
: ASHIFTRT
,
7185 mode
, tem
, modewidth
- len
);
7187 else if (unsignedp
&& len
< HOST_BITS_PER_WIDE_INT
)
7188 tem
= simplify_and_const_int (NULL_RTX
, GET_MODE (x
),
7189 simplify_shift_const (NULL_RTX
, LSHIFTRT
,
7192 (HOST_WIDE_INT_1U
<< len
) - 1);
7194 /* Any other cases we can't handle. */
7197 /* If we couldn't do this for some reason, return the original
7199 if (GET_CODE (tem
) == CLOBBER
)
7205 /* X is a SET which contains an assignment of one object into
7206 a part of another (such as a bit-field assignment, STRICT_LOW_PART,
7207 or certain SUBREGS). If possible, convert it into a series of
7210 We half-heartedly support variable positions, but do not at all
7211 support variable lengths. */
7214 expand_field_assignment (const_rtx x
)
7217 rtx pos
; /* Always counts from low bit. */
7219 rtx mask
, cleared
, masked
;
7220 machine_mode compute_mode
;
7222 /* Loop until we find something we can't simplify. */
7225 if (GET_CODE (SET_DEST (x
)) == STRICT_LOW_PART
7226 && GET_CODE (XEXP (SET_DEST (x
), 0)) == SUBREG
)
7228 inner
= SUBREG_REG (XEXP (SET_DEST (x
), 0));
7229 len
= GET_MODE_PRECISION (GET_MODE (XEXP (SET_DEST (x
), 0)));
7230 pos
= GEN_INT (subreg_lsb (XEXP (SET_DEST (x
), 0)));
7232 else if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
7233 && CONST_INT_P (XEXP (SET_DEST (x
), 1)))
7235 inner
= XEXP (SET_DEST (x
), 0);
7236 len
= INTVAL (XEXP (SET_DEST (x
), 1));
7237 pos
= XEXP (SET_DEST (x
), 2);
7239 /* A constant position should stay within the width of INNER. */
7240 if (CONST_INT_P (pos
)
7241 && INTVAL (pos
) + len
> GET_MODE_PRECISION (GET_MODE (inner
)))
7244 if (BITS_BIG_ENDIAN
)
7246 if (CONST_INT_P (pos
))
7247 pos
= GEN_INT (GET_MODE_PRECISION (GET_MODE (inner
)) - len
7249 else if (GET_CODE (pos
) == MINUS
7250 && CONST_INT_P (XEXP (pos
, 1))
7251 && (INTVAL (XEXP (pos
, 1))
7252 == GET_MODE_PRECISION (GET_MODE (inner
)) - len
))
7253 /* If position is ADJUST - X, new position is X. */
7254 pos
= XEXP (pos
, 0);
7257 HOST_WIDE_INT prec
= GET_MODE_PRECISION (GET_MODE (inner
));
7258 pos
= simplify_gen_binary (MINUS
, GET_MODE (pos
),
7259 gen_int_mode (prec
- len
,
7266 /* A SUBREG between two modes that occupy the same numbers of words
7267 can be done by moving the SUBREG to the source. */
7268 else if (GET_CODE (SET_DEST (x
)) == SUBREG
7269 /* We need SUBREGs to compute nonzero_bits properly. */
7270 && nonzero_sign_valid
7271 && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x
)))
7272 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
7273 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x
))))
7274 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)))
7276 x
= gen_rtx_SET (SUBREG_REG (SET_DEST (x
)),
7278 (GET_MODE (SUBREG_REG (SET_DEST (x
))),
7285 while (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
7286 inner
= SUBREG_REG (inner
);
7288 compute_mode
= GET_MODE (inner
);
7290 /* Don't attempt bitwise arithmetic on non scalar integer modes. */
7291 if (! SCALAR_INT_MODE_P (compute_mode
))
7295 /* Don't do anything for vector or complex integral types. */
7296 if (! FLOAT_MODE_P (compute_mode
))
7299 /* Try to find an integral mode to pun with. */
7300 imode
= mode_for_size (GET_MODE_BITSIZE (compute_mode
), MODE_INT
, 0);
7301 if (imode
== BLKmode
)
7304 compute_mode
= imode
;
7305 inner
= gen_lowpart (imode
, inner
);
7308 /* Compute a mask of LEN bits, if we can do this on the host machine. */
7309 if (len
>= HOST_BITS_PER_WIDE_INT
)
7312 /* Don't try to compute in too wide unsupported modes. */
7313 if (!targetm
.scalar_mode_supported_p (compute_mode
))
7316 /* Now compute the equivalent expression. Make a copy of INNER
7317 for the SET_DEST in case it is a MEM into which we will substitute;
7318 we don't want shared RTL in that case. */
7319 mask
= gen_int_mode ((HOST_WIDE_INT_1U
<< len
) - 1,
7321 cleared
= simplify_gen_binary (AND
, compute_mode
,
7322 simplify_gen_unary (NOT
, compute_mode
,
7323 simplify_gen_binary (ASHIFT
,
7328 masked
= simplify_gen_binary (ASHIFT
, compute_mode
,
7329 simplify_gen_binary (
7331 gen_lowpart (compute_mode
, SET_SRC (x
)),
7335 x
= gen_rtx_SET (copy_rtx (inner
),
7336 simplify_gen_binary (IOR
, compute_mode
,
7343 /* Return an RTX for a reference to LEN bits of INNER. If POS_RTX is nonzero,
7344 it is an RTX that represents the (variable) starting position; otherwise,
7345 POS is the (constant) starting bit position. Both are counted from the LSB.
7347 UNSIGNEDP is nonzero for an unsigned reference and zero for a signed one.
7349 IN_DEST is nonzero if this is a reference in the destination of a SET.
7350 This is used when a ZERO_ or SIGN_EXTRACT isn't needed. If nonzero,
7351 a STRICT_LOW_PART will be used, if zero, ZERO_EXTEND or SIGN_EXTEND will
7354 IN_COMPARE is nonzero if we are in a COMPARE. This means that a
7355 ZERO_EXTRACT should be built even for bits starting at bit 0.
7357 MODE is the desired mode of the result (if IN_DEST == 0).
7359 The result is an RTX for the extraction or NULL_RTX if the target
7363 make_extraction (machine_mode mode
, rtx inner
, HOST_WIDE_INT pos
,
7364 rtx pos_rtx
, unsigned HOST_WIDE_INT len
, int unsignedp
,
7365 int in_dest
, int in_compare
)
7367 /* This mode describes the size of the storage area
7368 to fetch the overall value from. Within that, we
7369 ignore the POS lowest bits, etc. */
7370 machine_mode is_mode
= GET_MODE (inner
);
7371 machine_mode inner_mode
;
7372 machine_mode wanted_inner_mode
;
7373 machine_mode wanted_inner_reg_mode
= word_mode
;
7374 machine_mode pos_mode
= word_mode
;
7375 machine_mode extraction_mode
= word_mode
;
7376 machine_mode tmode
= mode_for_size (len
, MODE_INT
, 1);
7378 rtx orig_pos_rtx
= pos_rtx
;
7379 HOST_WIDE_INT orig_pos
;
7381 if (pos_rtx
&& CONST_INT_P (pos_rtx
))
7382 pos
= INTVAL (pos_rtx
), pos_rtx
= 0;
7384 if (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
7386 /* If going from (subreg:SI (mem:QI ...)) to (mem:QI ...),
7387 consider just the QI as the memory to extract from.
7388 The subreg adds or removes high bits; its mode is
7389 irrelevant to the meaning of this extraction,
7390 since POS and LEN count from the lsb. */
7391 if (MEM_P (SUBREG_REG (inner
)))
7392 is_mode
= GET_MODE (SUBREG_REG (inner
));
7393 inner
= SUBREG_REG (inner
);
7395 else if (GET_CODE (inner
) == ASHIFT
7396 && CONST_INT_P (XEXP (inner
, 1))
7397 && pos_rtx
== 0 && pos
== 0
7398 && len
> UINTVAL (XEXP (inner
, 1)))
7400 /* We're extracting the least significant bits of an rtx
7401 (ashift X (const_int C)), where LEN > C. Extract the
7402 least significant (LEN - C) bits of X, giving an rtx
7403 whose mode is MODE, then shift it left C times. */
7404 new_rtx
= make_extraction (mode
, XEXP (inner
, 0),
7405 0, 0, len
- INTVAL (XEXP (inner
, 1)),
7406 unsignedp
, in_dest
, in_compare
);
7408 return gen_rtx_ASHIFT (mode
, new_rtx
, XEXP (inner
, 1));
7410 else if (GET_CODE (inner
) == TRUNCATE
)
7411 inner
= XEXP (inner
, 0);
7413 inner_mode
= GET_MODE (inner
);
7415 /* See if this can be done without an extraction. We never can if the
7416 width of the field is not the same as that of some integer mode. For
7417 registers, we can only avoid the extraction if the position is at the
7418 low-order bit and this is either not in the destination or we have the
7419 appropriate STRICT_LOW_PART operation available.
7421 For MEM, we can avoid an extract if the field starts on an appropriate
7422 boundary and we can change the mode of the memory reference. */
7424 if (tmode
!= BLKmode
7425 && ((pos_rtx
== 0 && (pos
% BITS_PER_WORD
) == 0
7427 && (pos
== 0 || REG_P (inner
))
7428 && (inner_mode
== tmode
7430 || TRULY_NOOP_TRUNCATION_MODES_P (tmode
, inner_mode
)
7431 || reg_truncated_to_mode (tmode
, inner
))
7434 && have_insn_for (STRICT_LOW_PART
, tmode
))))
7435 || (MEM_P (inner
) && pos_rtx
== 0
7437 % (STRICT_ALIGNMENT
? GET_MODE_ALIGNMENT (tmode
)
7438 : BITS_PER_UNIT
)) == 0
7439 /* We can't do this if we are widening INNER_MODE (it
7440 may not be aligned, for one thing). */
7441 && GET_MODE_PRECISION (inner_mode
) >= GET_MODE_PRECISION (tmode
)
7442 && (inner_mode
== tmode
7443 || (! mode_dependent_address_p (XEXP (inner
, 0),
7444 MEM_ADDR_SPACE (inner
))
7445 && ! MEM_VOLATILE_P (inner
))))))
7447 /* If INNER is a MEM, make a new MEM that encompasses just the desired
7448 field. If the original and current mode are the same, we need not
7449 adjust the offset. Otherwise, we do if bytes big endian.
7451 If INNER is not a MEM, get a piece consisting of just the field
7452 of interest (in this case POS % BITS_PER_WORD must be 0). */
7456 HOST_WIDE_INT offset
;
7458 /* POS counts from lsb, but make OFFSET count in memory order. */
7459 if (BYTES_BIG_ENDIAN
)
7460 offset
= (GET_MODE_PRECISION (is_mode
) - len
- pos
) / BITS_PER_UNIT
;
7462 offset
= pos
/ BITS_PER_UNIT
;
7464 new_rtx
= adjust_address_nv (inner
, tmode
, offset
);
7466 else if (REG_P (inner
))
7468 if (tmode
!= inner_mode
)
7470 /* We can't call gen_lowpart in a DEST since we
7471 always want a SUBREG (see below) and it would sometimes
7472 return a new hard register. */
7475 HOST_WIDE_INT final_word
= pos
/ BITS_PER_WORD
;
7477 if (WORDS_BIG_ENDIAN
7478 && GET_MODE_SIZE (inner_mode
) > UNITS_PER_WORD
)
7479 final_word
= ((GET_MODE_SIZE (inner_mode
)
7480 - GET_MODE_SIZE (tmode
))
7481 / UNITS_PER_WORD
) - final_word
;
7483 final_word
*= UNITS_PER_WORD
;
7484 if (BYTES_BIG_ENDIAN
&&
7485 GET_MODE_SIZE (inner_mode
) > GET_MODE_SIZE (tmode
))
7486 final_word
+= (GET_MODE_SIZE (inner_mode
)
7487 - GET_MODE_SIZE (tmode
)) % UNITS_PER_WORD
;
7489 /* Avoid creating invalid subregs, for example when
7490 simplifying (x>>32)&255. */
7491 if (!validate_subreg (tmode
, inner_mode
, inner
, final_word
))
7494 new_rtx
= gen_rtx_SUBREG (tmode
, inner
, final_word
);
7497 new_rtx
= gen_lowpart (tmode
, inner
);
7503 new_rtx
= force_to_mode (inner
, tmode
,
7504 len
>= HOST_BITS_PER_WIDE_INT
7506 : (HOST_WIDE_INT_1U
<< len
) - 1, 0);
7508 /* If this extraction is going into the destination of a SET,
7509 make a STRICT_LOW_PART unless we made a MEM. */
7512 return (MEM_P (new_rtx
) ? new_rtx
7513 : (GET_CODE (new_rtx
) != SUBREG
7514 ? gen_rtx_CLOBBER (tmode
, const0_rtx
)
7515 : gen_rtx_STRICT_LOW_PART (VOIDmode
, new_rtx
)));
7520 if (CONST_SCALAR_INT_P (new_rtx
))
7521 return simplify_unary_operation (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
7522 mode
, new_rtx
, tmode
);
7524 /* If we know that no extraneous bits are set, and that the high
7525 bit is not set, convert the extraction to the cheaper of
7526 sign and zero extension, that are equivalent in these cases. */
7527 if (flag_expensive_optimizations
7528 && (HWI_COMPUTABLE_MODE_P (tmode
)
7529 && ((nonzero_bits (new_rtx
, tmode
)
7530 & ~(((unsigned HOST_WIDE_INT
)GET_MODE_MASK (tmode
)) >> 1))
7533 rtx temp
= gen_rtx_ZERO_EXTEND (mode
, new_rtx
);
7534 rtx temp1
= gen_rtx_SIGN_EXTEND (mode
, new_rtx
);
7536 /* Prefer ZERO_EXTENSION, since it gives more information to
7538 if (set_src_cost (temp
, mode
, optimize_this_for_speed_p
)
7539 <= set_src_cost (temp1
, mode
, optimize_this_for_speed_p
))
7544 /* Otherwise, sign- or zero-extend unless we already are in the
7547 return (gen_rtx_fmt_e (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
7551 /* Unless this is a COMPARE or we have a funny memory reference,
7552 don't do anything with zero-extending field extracts starting at
7553 the low-order bit since they are simple AND operations. */
7554 if (pos_rtx
== 0 && pos
== 0 && ! in_dest
7555 && ! in_compare
&& unsignedp
)
7558 /* Unless INNER is not MEM, reject this if we would be spanning bytes or
7559 if the position is not a constant and the length is not 1. In all
7560 other cases, we would only be going outside our object in cases when
7561 an original shift would have been undefined. */
7563 && ((pos_rtx
== 0 && pos
+ len
> GET_MODE_PRECISION (is_mode
))
7564 || (pos_rtx
!= 0 && len
!= 1)))
7567 enum extraction_pattern pattern
= (in_dest
? EP_insv
7568 : unsignedp
? EP_extzv
: EP_extv
);
7570 /* If INNER is not from memory, we want it to have the mode of a register
7571 extraction pattern's structure operand, or word_mode if there is no
7572 such pattern. The same applies to extraction_mode and pos_mode
7573 and their respective operands.
7575 For memory, assume that the desired extraction_mode and pos_mode
7576 are the same as for a register operation, since at present we don't
7577 have named patterns for aligned memory structures. */
7578 struct extraction_insn insn
;
7579 if (get_best_reg_extraction_insn (&insn
, pattern
,
7580 GET_MODE_BITSIZE (inner_mode
), mode
))
7582 wanted_inner_reg_mode
= insn
.struct_mode
;
7583 pos_mode
= insn
.pos_mode
;
7584 extraction_mode
= insn
.field_mode
;
7587 /* Never narrow an object, since that might not be safe. */
7589 if (mode
!= VOIDmode
7590 && GET_MODE_SIZE (extraction_mode
) < GET_MODE_SIZE (mode
))
7591 extraction_mode
= mode
;
7594 wanted_inner_mode
= wanted_inner_reg_mode
;
7597 /* Be careful not to go beyond the extracted object and maintain the
7598 natural alignment of the memory. */
7599 wanted_inner_mode
= smallest_mode_for_size (len
, MODE_INT
);
7600 while (pos
% GET_MODE_BITSIZE (wanted_inner_mode
) + len
7601 > GET_MODE_BITSIZE (wanted_inner_mode
))
7603 wanted_inner_mode
= GET_MODE_WIDER_MODE (wanted_inner_mode
);
7604 gcc_assert (wanted_inner_mode
!= VOIDmode
);
7610 if (BITS_BIG_ENDIAN
)
7612 /* POS is passed as if BITS_BIG_ENDIAN == 0, so we need to convert it to
7613 BITS_BIG_ENDIAN style. If position is constant, compute new
7614 position. Otherwise, build subtraction.
7615 Note that POS is relative to the mode of the original argument.
7616 If it's a MEM we need to recompute POS relative to that.
7617 However, if we're extracting from (or inserting into) a register,
7618 we want to recompute POS relative to wanted_inner_mode. */
7619 int width
= (MEM_P (inner
)
7620 ? GET_MODE_BITSIZE (is_mode
)
7621 : GET_MODE_BITSIZE (wanted_inner_mode
));
7624 pos
= width
- len
- pos
;
7627 = gen_rtx_MINUS (GET_MODE (pos_rtx
),
7628 gen_int_mode (width
- len
, GET_MODE (pos_rtx
)),
7630 /* POS may be less than 0 now, but we check for that below.
7631 Note that it can only be less than 0 if !MEM_P (inner). */
7634 /* If INNER has a wider mode, and this is a constant extraction, try to
7635 make it smaller and adjust the byte to point to the byte containing
7637 if (wanted_inner_mode
!= VOIDmode
7638 && inner_mode
!= wanted_inner_mode
7640 && GET_MODE_SIZE (wanted_inner_mode
) < GET_MODE_SIZE (is_mode
)
7642 && ! mode_dependent_address_p (XEXP (inner
, 0), MEM_ADDR_SPACE (inner
))
7643 && ! MEM_VOLATILE_P (inner
))
7647 /* The computations below will be correct if the machine is big
7648 endian in both bits and bytes or little endian in bits and bytes.
7649 If it is mixed, we must adjust. */
7651 /* If bytes are big endian and we had a paradoxical SUBREG, we must
7652 adjust OFFSET to compensate. */
7653 if (BYTES_BIG_ENDIAN
7654 && GET_MODE_SIZE (inner_mode
) < GET_MODE_SIZE (is_mode
))
7655 offset
-= GET_MODE_SIZE (is_mode
) - GET_MODE_SIZE (inner_mode
);
7657 /* We can now move to the desired byte. */
7658 offset
+= (pos
/ GET_MODE_BITSIZE (wanted_inner_mode
))
7659 * GET_MODE_SIZE (wanted_inner_mode
);
7660 pos
%= GET_MODE_BITSIZE (wanted_inner_mode
);
7662 if (BYTES_BIG_ENDIAN
!= BITS_BIG_ENDIAN
7663 && is_mode
!= wanted_inner_mode
)
7664 offset
= (GET_MODE_SIZE (is_mode
)
7665 - GET_MODE_SIZE (wanted_inner_mode
) - offset
);
7667 inner
= adjust_address_nv (inner
, wanted_inner_mode
, offset
);
7670 /* If INNER is not memory, get it into the proper mode. If we are changing
7671 its mode, POS must be a constant and smaller than the size of the new
7673 else if (!MEM_P (inner
))
7675 /* On the LHS, don't create paradoxical subregs implicitely truncating
7676 the register unless TRULY_NOOP_TRUNCATION. */
7678 && !TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (inner
),
7682 if (GET_MODE (inner
) != wanted_inner_mode
7684 || orig_pos
+ len
> GET_MODE_BITSIZE (wanted_inner_mode
)))
7690 inner
= force_to_mode (inner
, wanted_inner_mode
,
7692 || len
+ orig_pos
>= HOST_BITS_PER_WIDE_INT
7694 : (((HOST_WIDE_INT_1U
<< len
) - 1)
7699 /* Adjust mode of POS_RTX, if needed. If we want a wider mode, we
7700 have to zero extend. Otherwise, we can just use a SUBREG. */
7702 && GET_MODE_SIZE (pos_mode
) > GET_MODE_SIZE (GET_MODE (pos_rtx
)))
7704 rtx temp
= simplify_gen_unary (ZERO_EXTEND
, pos_mode
, pos_rtx
,
7705 GET_MODE (pos_rtx
));
7707 /* If we know that no extraneous bits are set, and that the high
7708 bit is not set, convert extraction to cheaper one - either
7709 SIGN_EXTENSION or ZERO_EXTENSION, that are equivalent in these
7711 if (flag_expensive_optimizations
7712 && (HWI_COMPUTABLE_MODE_P (GET_MODE (pos_rtx
))
7713 && ((nonzero_bits (pos_rtx
, GET_MODE (pos_rtx
))
7714 & ~(((unsigned HOST_WIDE_INT
)
7715 GET_MODE_MASK (GET_MODE (pos_rtx
)))
7719 rtx temp1
= simplify_gen_unary (SIGN_EXTEND
, pos_mode
, pos_rtx
,
7720 GET_MODE (pos_rtx
));
7722 /* Prefer ZERO_EXTENSION, since it gives more information to
7724 if (set_src_cost (temp1
, pos_mode
, optimize_this_for_speed_p
)
7725 < set_src_cost (temp
, pos_mode
, optimize_this_for_speed_p
))
7731 /* Make POS_RTX unless we already have it and it is correct. If we don't
7732 have a POS_RTX but we do have an ORIG_POS_RTX, the latter must
7734 if (pos_rtx
== 0 && orig_pos_rtx
!= 0 && INTVAL (orig_pos_rtx
) == pos
)
7735 pos_rtx
= orig_pos_rtx
;
7737 else if (pos_rtx
== 0)
7738 pos_rtx
= GEN_INT (pos
);
7740 /* Make the required operation. See if we can use existing rtx. */
7741 new_rtx
= gen_rtx_fmt_eee (unsignedp
? ZERO_EXTRACT
: SIGN_EXTRACT
,
7742 extraction_mode
, inner
, GEN_INT (len
), pos_rtx
);
7744 new_rtx
= gen_lowpart (mode
, new_rtx
);
7749 /* See if X contains an ASHIFT of COUNT or more bits that can be commuted
7750 with any other operations in X. Return X without that shift if so. */
7753 extract_left_shift (rtx x
, int count
)
7755 enum rtx_code code
= GET_CODE (x
);
7756 machine_mode mode
= GET_MODE (x
);
7762 /* This is the shift itself. If it is wide enough, we will return
7763 either the value being shifted if the shift count is equal to
7764 COUNT or a shift for the difference. */
7765 if (CONST_INT_P (XEXP (x
, 1))
7766 && INTVAL (XEXP (x
, 1)) >= count
)
7767 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (x
, 0),
7768 INTVAL (XEXP (x
, 1)) - count
);
7772 if ((tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
7773 return simplify_gen_unary (code
, mode
, tem
, mode
);
7777 case PLUS
: case IOR
: case XOR
: case AND
:
7778 /* If we can safely shift this constant and we find the inner shift,
7779 make a new operation. */
7780 if (CONST_INT_P (XEXP (x
, 1))
7781 && (UINTVAL (XEXP (x
, 1))
7782 & (((HOST_WIDE_INT_1U
<< count
)) - 1)) == 0
7783 && (tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
7785 HOST_WIDE_INT val
= INTVAL (XEXP (x
, 1)) >> count
;
7786 return simplify_gen_binary (code
, mode
, tem
,
7787 gen_int_mode (val
, mode
));
7798 /* Subroutine of make_compound_operation. *X_PTR is the rtx at the current
7799 level of the expression and MODE is its mode. IN_CODE is as for
7800 make_compound_operation. *NEXT_CODE_PTR is the value of IN_CODE
7801 that should be used when recursing on operands of *X_PTR.
7803 There are two possible actions:
7805 - Return null. This tells the caller to recurse on *X_PTR with IN_CODE
7806 equal to *NEXT_CODE_PTR, after which *X_PTR holds the final value.
7808 - Return a new rtx, which the caller returns directly. */
7811 make_compound_operation_int (machine_mode mode
, rtx
*x_ptr
,
7812 enum rtx_code in_code
,
7813 enum rtx_code
*next_code_ptr
)
7816 enum rtx_code next_code
= *next_code_ptr
;
7817 enum rtx_code code
= GET_CODE (x
);
7818 int mode_width
= GET_MODE_PRECISION (mode
);
7823 bool equality_comparison
= false;
7827 equality_comparison
= true;
7831 /* Process depending on the code of this operation. If NEW is set
7832 nonzero, it will be returned. */
7837 /* Convert shifts by constants into multiplications if inside
7839 if (in_code
== MEM
&& CONST_INT_P (XEXP (x
, 1))
7840 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
7841 && INTVAL (XEXP (x
, 1)) >= 0)
7843 HOST_WIDE_INT count
= INTVAL (XEXP (x
, 1));
7844 HOST_WIDE_INT multval
= HOST_WIDE_INT_1
<< count
;
7846 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
7847 if (GET_CODE (new_rtx
) == NEG
)
7849 new_rtx
= XEXP (new_rtx
, 0);
7852 multval
= trunc_int_for_mode (multval
, mode
);
7853 new_rtx
= gen_rtx_MULT (mode
, new_rtx
, gen_int_mode (multval
, mode
));
7860 lhs
= make_compound_operation (lhs
, next_code
);
7861 rhs
= make_compound_operation (rhs
, next_code
);
7862 if (GET_CODE (lhs
) == MULT
&& GET_CODE (XEXP (lhs
, 0)) == NEG
)
7864 tem
= simplify_gen_binary (MULT
, mode
, XEXP (XEXP (lhs
, 0), 0),
7866 new_rtx
= simplify_gen_binary (MINUS
, mode
, rhs
, tem
);
7868 else if (GET_CODE (lhs
) == MULT
7869 && (CONST_INT_P (XEXP (lhs
, 1)) && INTVAL (XEXP (lhs
, 1)) < 0))
7871 tem
= simplify_gen_binary (MULT
, mode
, XEXP (lhs
, 0),
7872 simplify_gen_unary (NEG
, mode
,
7875 new_rtx
= simplify_gen_binary (MINUS
, mode
, rhs
, tem
);
7879 SUBST (XEXP (x
, 0), lhs
);
7880 SUBST (XEXP (x
, 1), rhs
);
7882 maybe_swap_commutative_operands (x
);
7888 lhs
= make_compound_operation (lhs
, next_code
);
7889 rhs
= make_compound_operation (rhs
, next_code
);
7890 if (GET_CODE (rhs
) == MULT
&& GET_CODE (XEXP (rhs
, 0)) == NEG
)
7892 tem
= simplify_gen_binary (MULT
, mode
, XEXP (XEXP (rhs
, 0), 0),
7894 return simplify_gen_binary (PLUS
, mode
, tem
, lhs
);
7896 else if (GET_CODE (rhs
) == MULT
7897 && (CONST_INT_P (XEXP (rhs
, 1)) && INTVAL (XEXP (rhs
, 1)) < 0))
7899 tem
= simplify_gen_binary (MULT
, mode
, XEXP (rhs
, 0),
7900 simplify_gen_unary (NEG
, mode
,
7903 return simplify_gen_binary (PLUS
, mode
, tem
, lhs
);
7907 SUBST (XEXP (x
, 0), lhs
);
7908 SUBST (XEXP (x
, 1), rhs
);
7913 /* If the second operand is not a constant, we can't do anything
7915 if (!CONST_INT_P (XEXP (x
, 1)))
7918 /* If the constant is a power of two minus one and the first operand
7919 is a logical right shift, make an extraction. */
7920 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
7921 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7923 new_rtx
= make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
7924 new_rtx
= make_extraction (mode
, new_rtx
, 0, XEXP (XEXP (x
, 0), 1), i
, 1,
7925 0, in_code
== COMPARE
);
7928 /* Same as previous, but for (subreg (lshiftrt ...)) in first op. */
7929 else if (GET_CODE (XEXP (x
, 0)) == SUBREG
7930 && subreg_lowpart_p (XEXP (x
, 0))
7931 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == LSHIFTRT
7932 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7934 rtx inner_x0
= SUBREG_REG (XEXP (x
, 0));
7935 machine_mode inner_mode
= GET_MODE (inner_x0
);
7936 new_rtx
= make_compound_operation (XEXP (inner_x0
, 0), next_code
);
7937 new_rtx
= make_extraction (inner_mode
, new_rtx
, 0,
7939 i
, 1, 0, in_code
== COMPARE
);
7943 /* If we narrowed the mode when dropping the subreg, then
7944 we must zero-extend to keep the semantics of the AND. */
7945 if (GET_MODE_SIZE (inner_mode
) >= GET_MODE_SIZE (mode
))
7947 else if (SCALAR_INT_MODE_P (inner_mode
))
7948 new_rtx
= simplify_gen_unary (ZERO_EXTEND
, mode
,
7949 new_rtx
, inner_mode
);
7954 /* If that didn't give anything, see if the AND simplifies on
7956 if (!new_rtx
&& i
>= 0)
7958 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
7959 new_rtx
= make_extraction (mode
, new_rtx
, 0, NULL_RTX
, i
, 1,
7960 0, in_code
== COMPARE
);
7963 /* Same as previous, but for (xor/ior (lshiftrt...) (lshiftrt...)). */
7964 else if ((GET_CODE (XEXP (x
, 0)) == XOR
7965 || GET_CODE (XEXP (x
, 0)) == IOR
)
7966 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == LSHIFTRT
7967 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == LSHIFTRT
7968 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7970 /* Apply the distributive law, and then try to make extractions. */
7971 new_rtx
= gen_rtx_fmt_ee (GET_CODE (XEXP (x
, 0)), mode
,
7972 gen_rtx_AND (mode
, XEXP (XEXP (x
, 0), 0),
7974 gen_rtx_AND (mode
, XEXP (XEXP (x
, 0), 1),
7976 new_rtx
= make_compound_operation (new_rtx
, in_code
);
7979 /* If we are have (and (rotate X C) M) and C is larger than the number
7980 of bits in M, this is an extraction. */
7982 else if (GET_CODE (XEXP (x
, 0)) == ROTATE
7983 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
7984 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0
7985 && i
<= INTVAL (XEXP (XEXP (x
, 0), 1)))
7987 new_rtx
= make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
7988 new_rtx
= make_extraction (mode
, new_rtx
,
7989 (GET_MODE_PRECISION (mode
)
7990 - INTVAL (XEXP (XEXP (x
, 0), 1))),
7991 NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
7994 /* On machines without logical shifts, if the operand of the AND is
7995 a logical shift and our mask turns off all the propagated sign
7996 bits, we can replace the logical shift with an arithmetic shift. */
7997 else if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
7998 && !have_insn_for (LSHIFTRT
, mode
)
7999 && have_insn_for (ASHIFTRT
, mode
)
8000 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
8001 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
8002 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
8003 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
8005 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
8007 mask
>>= INTVAL (XEXP (XEXP (x
, 0), 1));
8008 if ((INTVAL (XEXP (x
, 1)) & ~mask
) == 0)
8010 gen_rtx_ASHIFTRT (mode
,
8011 make_compound_operation
8012 (XEXP (XEXP (x
, 0), 0), next_code
),
8013 XEXP (XEXP (x
, 0), 1)));
8016 /* If the constant is one less than a power of two, this might be
8017 representable by an extraction even if no shift is present.
8018 If it doesn't end up being a ZERO_EXTEND, we will ignore it unless
8019 we are in a COMPARE. */
8020 else if ((i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
8021 new_rtx
= make_extraction (mode
,
8022 make_compound_operation (XEXP (x
, 0),
8024 0, NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
8026 /* If we are in a comparison and this is an AND with a power of two,
8027 convert this into the appropriate bit extract. */
8028 else if (in_code
== COMPARE
8029 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0
8030 && (equality_comparison
|| i
< GET_MODE_PRECISION (mode
) - 1))
8031 new_rtx
= make_extraction (mode
,
8032 make_compound_operation (XEXP (x
, 0),
8034 i
, NULL_RTX
, 1, 1, 0, 1);
8036 /* If the one operand is a paradoxical subreg of a register or memory and
8037 the constant (limited to the smaller mode) has only zero bits where
8038 the sub expression has known zero bits, this can be expressed as
8040 else if (GET_CODE (XEXP (x
, 0)) == SUBREG
)
8044 sub
= XEXP (XEXP (x
, 0), 0);
8045 machine_mode sub_mode
= GET_MODE (sub
);
8046 if ((REG_P (sub
) || MEM_P (sub
))
8047 && GET_MODE_PRECISION (sub_mode
) < mode_width
)
8049 unsigned HOST_WIDE_INT mode_mask
= GET_MODE_MASK (sub_mode
);
8050 unsigned HOST_WIDE_INT mask
;
8052 /* original AND constant with all the known zero bits set */
8053 mask
= UINTVAL (XEXP (x
, 1)) | (~nonzero_bits (sub
, sub_mode
));
8054 if ((mask
& mode_mask
) == mode_mask
)
8056 new_rtx
= make_compound_operation (sub
, next_code
);
8057 new_rtx
= make_extraction (mode
, new_rtx
, 0, 0,
8058 GET_MODE_PRECISION (sub_mode
),
8059 1, 0, in_code
== COMPARE
);
8067 /* If the sign bit is known to be zero, replace this with an
8068 arithmetic shift. */
8069 if (have_insn_for (ASHIFTRT
, mode
)
8070 && ! have_insn_for (LSHIFTRT
, mode
)
8071 && mode_width
<= HOST_BITS_PER_WIDE_INT
8072 && (nonzero_bits (XEXP (x
, 0), mode
) & (1 << (mode_width
- 1))) == 0)
8074 new_rtx
= gen_rtx_ASHIFTRT (mode
,
8075 make_compound_operation (XEXP (x
, 0),
8087 /* If we have (ashiftrt (ashift foo C1) C2) with C2 >= C1,
8088 this is a SIGN_EXTRACT. */
8089 if (CONST_INT_P (rhs
)
8090 && GET_CODE (lhs
) == ASHIFT
8091 && CONST_INT_P (XEXP (lhs
, 1))
8092 && INTVAL (rhs
) >= INTVAL (XEXP (lhs
, 1))
8093 && INTVAL (XEXP (lhs
, 1)) >= 0
8094 && INTVAL (rhs
) < mode_width
)
8096 new_rtx
= make_compound_operation (XEXP (lhs
, 0), next_code
);
8097 new_rtx
= make_extraction (mode
, new_rtx
,
8098 INTVAL (rhs
) - INTVAL (XEXP (lhs
, 1)),
8099 NULL_RTX
, mode_width
- INTVAL (rhs
),
8100 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
8104 /* See if we have operations between an ASHIFTRT and an ASHIFT.
8105 If so, try to merge the shifts into a SIGN_EXTEND. We could
8106 also do this for some cases of SIGN_EXTRACT, but it doesn't
8107 seem worth the effort; the case checked for occurs on Alpha. */
8110 && ! (GET_CODE (lhs
) == SUBREG
8111 && (OBJECT_P (SUBREG_REG (lhs
))))
8112 && CONST_INT_P (rhs
)
8113 && INTVAL (rhs
) >= 0
8114 && INTVAL (rhs
) < HOST_BITS_PER_WIDE_INT
8115 && INTVAL (rhs
) < mode_width
8116 && (new_rtx
= extract_left_shift (lhs
, INTVAL (rhs
))) != 0)
8117 new_rtx
= make_extraction (mode
, make_compound_operation (new_rtx
, next_code
),
8118 0, NULL_RTX
, mode_width
- INTVAL (rhs
),
8119 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
8124 /* Call ourselves recursively on the inner expression. If we are
8125 narrowing the object and it has a different RTL code from
8126 what it originally did, do this SUBREG as a force_to_mode. */
8128 rtx inner
= SUBREG_REG (x
), simplified
;
8129 enum rtx_code subreg_code
= in_code
;
8131 /* If the SUBREG is masking of a logical right shift,
8132 make an extraction. */
8133 if (GET_CODE (inner
) == LSHIFTRT
8134 && CONST_INT_P (XEXP (inner
, 1))
8135 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (inner
))
8136 && (UINTVAL (XEXP (inner
, 1))
8137 < GET_MODE_PRECISION (GET_MODE (inner
)))
8138 && subreg_lowpart_p (x
))
8140 new_rtx
= make_compound_operation (XEXP (inner
, 0), next_code
);
8141 int width
= GET_MODE_PRECISION (GET_MODE (inner
))
8142 - INTVAL (XEXP (inner
, 1));
8143 if (width
> mode_width
)
8145 new_rtx
= make_extraction (mode
, new_rtx
, 0, XEXP (inner
, 1),
8146 width
, 1, 0, in_code
== COMPARE
);
8150 /* If in_code is COMPARE, it isn't always safe to pass it through
8151 to the recursive make_compound_operation call. */
8152 if (subreg_code
== COMPARE
8153 && (!subreg_lowpart_p (x
)
8154 || GET_CODE (inner
) == SUBREG
8155 /* (subreg:SI (and:DI (reg:DI) (const_int 0x800000000)) 0)
8156 is (const_int 0), rather than
8157 (subreg:SI (lshiftrt:DI (reg:DI) (const_int 35)) 0). */
8158 || (GET_CODE (inner
) == AND
8159 && CONST_INT_P (XEXP (inner
, 1))
8160 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (inner
))
8161 && exact_log2 (UINTVAL (XEXP (inner
, 1)))
8162 >= GET_MODE_BITSIZE (mode
))))
8165 tem
= make_compound_operation (inner
, subreg_code
);
8168 = simplify_subreg (mode
, tem
, GET_MODE (inner
), SUBREG_BYTE (x
));
8172 if (GET_CODE (tem
) != GET_CODE (inner
)
8173 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (inner
))
8174 && subreg_lowpart_p (x
))
8177 = force_to_mode (tem
, mode
, HOST_WIDE_INT_M1U
, 0);
8179 /* If we have something other than a SUBREG, we might have
8180 done an expansion, so rerun ourselves. */
8181 if (GET_CODE (newer
) != SUBREG
)
8182 newer
= make_compound_operation (newer
, in_code
);
8184 /* force_to_mode can expand compounds. If it just re-expanded the
8185 compound, use gen_lowpart to convert to the desired mode. */
8186 if (rtx_equal_p (newer
, x
)
8187 /* Likewise if it re-expanded the compound only partially.
8188 This happens for SUBREG of ZERO_EXTRACT if they extract
8189 the same number of bits. */
8190 || (GET_CODE (newer
) == SUBREG
8191 && (GET_CODE (SUBREG_REG (newer
)) == LSHIFTRT
8192 || GET_CODE (SUBREG_REG (newer
)) == ASHIFTRT
)
8193 && GET_CODE (inner
) == AND
8194 && rtx_equal_p (SUBREG_REG (newer
), XEXP (inner
, 0))))
8195 return gen_lowpart (GET_MODE (x
), tem
);
8210 *x_ptr
= gen_lowpart (mode
, new_rtx
);
8211 *next_code_ptr
= next_code
;
8215 /* Look at the expression rooted at X. Look for expressions
8216 equivalent to ZERO_EXTRACT, SIGN_EXTRACT, ZERO_EXTEND, SIGN_EXTEND.
8217 Form these expressions.
8219 Return the new rtx, usually just X.
8221 Also, for machines like the VAX that don't have logical shift insns,
8222 try to convert logical to arithmetic shift operations in cases where
8223 they are equivalent. This undoes the canonicalizations to logical
8224 shifts done elsewhere.
8226 We try, as much as possible, to re-use rtl expressions to save memory.
8228 IN_CODE says what kind of expression we are processing. Normally, it is
8229 SET. In a memory address it is MEM. When processing the arguments of
8230 a comparison or a COMPARE against zero, it is COMPARE, or EQ if more
8231 precisely it is an equality comparison against zero. */
8234 make_compound_operation (rtx x
, enum rtx_code in_code
)
8236 enum rtx_code code
= GET_CODE (x
);
8239 enum rtx_code next_code
;
8242 /* Select the code to be used in recursive calls. Once we are inside an
8243 address, we stay there. If we have a comparison, set to COMPARE,
8244 but once inside, go back to our default of SET. */
8246 next_code
= (code
== MEM
? MEM
8247 : ((code
== COMPARE
|| COMPARISON_P (x
))
8248 && XEXP (x
, 1) == const0_rtx
) ? COMPARE
8249 : in_code
== COMPARE
|| in_code
== EQ
? SET
: in_code
);
8251 if (SCALAR_INT_MODE_P (GET_MODE (x
)))
8253 rtx new_rtx
= make_compound_operation_int (GET_MODE (x
), &x
,
8254 in_code
, &next_code
);
8257 code
= GET_CODE (x
);
8260 /* Now recursively process each operand of this operation. We need to
8261 handle ZERO_EXTEND specially so that we don't lose track of the
8263 if (code
== ZERO_EXTEND
)
8265 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
8266 tem
= simplify_const_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
8267 new_rtx
, GET_MODE (XEXP (x
, 0)));
8270 SUBST (XEXP (x
, 0), new_rtx
);
8274 fmt
= GET_RTX_FORMAT (code
);
8275 for (i
= 0; i
< GET_RTX_LENGTH (code
); i
++)
8278 new_rtx
= make_compound_operation (XEXP (x
, i
), next_code
);
8279 SUBST (XEXP (x
, i
), new_rtx
);
8281 else if (fmt
[i
] == 'E')
8282 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
8284 new_rtx
= make_compound_operation (XVECEXP (x
, i
, j
), next_code
);
8285 SUBST (XVECEXP (x
, i
, j
), new_rtx
);
8288 maybe_swap_commutative_operands (x
);
8292 /* Given M see if it is a value that would select a field of bits
8293 within an item, but not the entire word. Return -1 if not.
8294 Otherwise, return the starting position of the field, where 0 is the
8297 *PLEN is set to the length of the field. */
8300 get_pos_from_mask (unsigned HOST_WIDE_INT m
, unsigned HOST_WIDE_INT
*plen
)
8302 /* Get the bit number of the first 1 bit from the right, -1 if none. */
8303 int pos
= m
? ctz_hwi (m
) : -1;
8307 /* Now shift off the low-order zero bits and see if we have a
8308 power of two minus 1. */
8309 len
= exact_log2 ((m
>> pos
) + 1);
8318 /* If X refers to a register that equals REG in value, replace these
8319 references with REG. */
8321 canon_reg_for_combine (rtx x
, rtx reg
)
8328 enum rtx_code code
= GET_CODE (x
);
8329 switch (GET_RTX_CLASS (code
))
8332 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8333 if (op0
!= XEXP (x
, 0))
8334 return simplify_gen_unary (GET_CODE (x
), GET_MODE (x
), op0
,
8339 case RTX_COMM_ARITH
:
8340 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8341 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8342 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8343 return simplify_gen_binary (GET_CODE (x
), GET_MODE (x
), op0
, op1
);
8347 case RTX_COMM_COMPARE
:
8348 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8349 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8350 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8351 return simplify_gen_relational (GET_CODE (x
), GET_MODE (x
),
8352 GET_MODE (op0
), op0
, op1
);
8356 case RTX_BITFIELD_OPS
:
8357 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8358 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8359 op2
= canon_reg_for_combine (XEXP (x
, 2), reg
);
8360 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1) || op2
!= XEXP (x
, 2))
8361 return simplify_gen_ternary (GET_CODE (x
), GET_MODE (x
),
8362 GET_MODE (op0
), op0
, op1
, op2
);
8368 if (rtx_equal_p (get_last_value (reg
), x
)
8369 || rtx_equal_p (reg
, get_last_value (x
)))
8378 fmt
= GET_RTX_FORMAT (code
);
8380 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
8383 rtx op
= canon_reg_for_combine (XEXP (x
, i
), reg
);
8384 if (op
!= XEXP (x
, i
))
8394 else if (fmt
[i
] == 'E')
8397 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
8399 rtx op
= canon_reg_for_combine (XVECEXP (x
, i
, j
), reg
);
8400 if (op
!= XVECEXP (x
, i
, j
))
8407 XVECEXP (x
, i
, j
) = op
;
8418 /* Return X converted to MODE. If the value is already truncated to
8419 MODE we can just return a subreg even though in the general case we
8420 would need an explicit truncation. */
8423 gen_lowpart_or_truncate (machine_mode mode
, rtx x
)
8425 if (!CONST_INT_P (x
)
8426 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (x
))
8427 && !TRULY_NOOP_TRUNCATION_MODES_P (mode
, GET_MODE (x
))
8428 && !(REG_P (x
) && reg_truncated_to_mode (mode
, x
)))
8430 /* Bit-cast X into an integer mode. */
8431 if (!SCALAR_INT_MODE_P (GET_MODE (x
)))
8432 x
= gen_lowpart (int_mode_for_mode (GET_MODE (x
)), x
);
8433 x
= simplify_gen_unary (TRUNCATE
, int_mode_for_mode (mode
),
8437 return gen_lowpart (mode
, x
);
8440 /* See if X can be simplified knowing that we will only refer to it in
8441 MODE and will only refer to those bits that are nonzero in MASK.
8442 If other bits are being computed or if masking operations are done
8443 that select a superset of the bits in MASK, they can sometimes be
8446 Return a possibly simplified expression, but always convert X to
8447 MODE. If X is a CONST_INT, AND the CONST_INT with MASK.
8449 If JUST_SELECT is nonzero, don't optimize by noticing that bits in MASK
8450 are all off in X. This is used when X will be complemented, by either
8451 NOT, NEG, or XOR. */
8454 force_to_mode (rtx x
, machine_mode mode
, unsigned HOST_WIDE_INT mask
,
8457 enum rtx_code code
= GET_CODE (x
);
8458 int next_select
= just_select
|| code
== XOR
|| code
== NOT
|| code
== NEG
;
8459 machine_mode op_mode
;
8460 unsigned HOST_WIDE_INT fuller_mask
, nonzero
;
8463 /* If this is a CALL or ASM_OPERANDS, don't do anything. Some of the
8464 code below will do the wrong thing since the mode of such an
8465 expression is VOIDmode.
8467 Also do nothing if X is a CLOBBER; this can happen if X was
8468 the return value from a call to gen_lowpart. */
8469 if (code
== CALL
|| code
== ASM_OPERANDS
|| code
== CLOBBER
)
8472 /* We want to perform the operation in its present mode unless we know
8473 that the operation is valid in MODE, in which case we do the operation
8475 op_mode
= ((GET_MODE_CLASS (mode
) == GET_MODE_CLASS (GET_MODE (x
))
8476 && have_insn_for (code
, mode
))
8477 ? mode
: GET_MODE (x
));
8479 /* It is not valid to do a right-shift in a narrower mode
8480 than the one it came in with. */
8481 if ((code
== LSHIFTRT
|| code
== ASHIFTRT
)
8482 && GET_MODE_PRECISION (mode
) < GET_MODE_PRECISION (GET_MODE (x
)))
8483 op_mode
= GET_MODE (x
);
8485 /* Truncate MASK to fit OP_MODE. */
8487 mask
&= GET_MODE_MASK (op_mode
);
8489 /* When we have an arithmetic operation, or a shift whose count we
8490 do not know, we need to assume that all bits up to the highest-order
8491 bit in MASK will be needed. This is how we form such a mask. */
8492 if (mask
& (HOST_WIDE_INT_1U
<< (HOST_BITS_PER_WIDE_INT
- 1)))
8493 fuller_mask
= HOST_WIDE_INT_M1U
;
8495 fuller_mask
= ((HOST_WIDE_INT_1U
<< (floor_log2 (mask
) + 1))
8498 /* Determine what bits of X are guaranteed to be (non)zero. */
8499 nonzero
= nonzero_bits (x
, mode
);
8501 /* If none of the bits in X are needed, return a zero. */
8502 if (!just_select
&& (nonzero
& mask
) == 0 && !side_effects_p (x
))
8505 /* If X is a CONST_INT, return a new one. Do this here since the
8506 test below will fail. */
8507 if (CONST_INT_P (x
))
8509 if (SCALAR_INT_MODE_P (mode
))
8510 return gen_int_mode (INTVAL (x
) & mask
, mode
);
8513 x
= GEN_INT (INTVAL (x
) & mask
);
8514 return gen_lowpart_common (mode
, x
);
8518 /* If X is narrower than MODE and we want all the bits in X's mode, just
8519 get X in the proper mode. */
8520 if (GET_MODE_SIZE (GET_MODE (x
)) < GET_MODE_SIZE (mode
)
8521 && (GET_MODE_MASK (GET_MODE (x
)) & ~mask
) == 0)
8522 return gen_lowpart (mode
, x
);
8524 /* We can ignore the effect of a SUBREG if it narrows the mode or
8525 if the constant masks to zero all the bits the mode doesn't have. */
8526 if (GET_CODE (x
) == SUBREG
8527 && subreg_lowpart_p (x
)
8528 && ((GET_MODE_SIZE (GET_MODE (x
))
8529 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
8531 & GET_MODE_MASK (GET_MODE (x
))
8532 & ~GET_MODE_MASK (GET_MODE (SUBREG_REG (x
)))))))
8533 return force_to_mode (SUBREG_REG (x
), mode
, mask
, next_select
);
8535 /* The arithmetic simplifications here only work for scalar integer modes. */
8536 if (!SCALAR_INT_MODE_P (mode
) || !SCALAR_INT_MODE_P (GET_MODE (x
)))
8537 return gen_lowpart_or_truncate (mode
, x
);
8542 /* If X is a (clobber (const_int)), return it since we know we are
8543 generating something that won't match. */
8550 x
= expand_compound_operation (x
);
8551 if (GET_CODE (x
) != code
)
8552 return force_to_mode (x
, mode
, mask
, next_select
);
8556 /* Similarly for a truncate. */
8557 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8560 /* If this is an AND with a constant, convert it into an AND
8561 whose constant is the AND of that constant with MASK. If it
8562 remains an AND of MASK, delete it since it is redundant. */
8564 if (CONST_INT_P (XEXP (x
, 1)))
8566 x
= simplify_and_const_int (x
, op_mode
, XEXP (x
, 0),
8567 mask
& INTVAL (XEXP (x
, 1)));
8569 /* If X is still an AND, see if it is an AND with a mask that
8570 is just some low-order bits. If so, and it is MASK, we don't
8573 if (GET_CODE (x
) == AND
&& CONST_INT_P (XEXP (x
, 1))
8574 && ((INTVAL (XEXP (x
, 1)) & GET_MODE_MASK (GET_MODE (x
)))
8578 /* If it remains an AND, try making another AND with the bits
8579 in the mode mask that aren't in MASK turned on. If the
8580 constant in the AND is wide enough, this might make a
8581 cheaper constant. */
8583 if (GET_CODE (x
) == AND
&& CONST_INT_P (XEXP (x
, 1))
8584 && GET_MODE_MASK (GET_MODE (x
)) != mask
8585 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
)))
8587 unsigned HOST_WIDE_INT cval
8588 = UINTVAL (XEXP (x
, 1))
8589 | (GET_MODE_MASK (GET_MODE (x
)) & ~mask
);
8592 y
= simplify_gen_binary (AND
, GET_MODE (x
), XEXP (x
, 0),
8593 gen_int_mode (cval
, GET_MODE (x
)));
8594 if (set_src_cost (y
, GET_MODE (x
), optimize_this_for_speed_p
)
8595 < set_src_cost (x
, GET_MODE (x
), optimize_this_for_speed_p
))
8605 /* In (and (plus FOO C1) M), if M is a mask that just turns off
8606 low-order bits (as in an alignment operation) and FOO is already
8607 aligned to that boundary, mask C1 to that boundary as well.
8608 This may eliminate that PLUS and, later, the AND. */
8611 unsigned int width
= GET_MODE_PRECISION (mode
);
8612 unsigned HOST_WIDE_INT smask
= mask
;
8614 /* If MODE is narrower than HOST_WIDE_INT and mask is a negative
8615 number, sign extend it. */
8617 if (width
< HOST_BITS_PER_WIDE_INT
8618 && (smask
& (HOST_WIDE_INT_1U
<< (width
- 1))) != 0)
8619 smask
|= HOST_WIDE_INT_M1U
<< width
;
8621 if (CONST_INT_P (XEXP (x
, 1))
8622 && pow2p_hwi (- smask
)
8623 && (nonzero_bits (XEXP (x
, 0), mode
) & ~smask
) == 0
8624 && (INTVAL (XEXP (x
, 1)) & ~smask
) != 0)
8625 return force_to_mode (plus_constant (GET_MODE (x
), XEXP (x
, 0),
8626 (INTVAL (XEXP (x
, 1)) & smask
)),
8627 mode
, smask
, next_select
);
8633 /* Substituting into the operands of a widening MULT is not likely to
8634 create RTL matching a machine insn. */
8636 && (GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
8637 || GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
)
8638 && (GET_CODE (XEXP (x
, 1)) == ZERO_EXTEND
8639 || GET_CODE (XEXP (x
, 1)) == SIGN_EXTEND
)
8640 && REG_P (XEXP (XEXP (x
, 0), 0))
8641 && REG_P (XEXP (XEXP (x
, 1), 0)))
8642 return gen_lowpart_or_truncate (mode
, x
);
8644 /* For PLUS, MINUS and MULT, we need any bits less significant than the
8645 most significant bit in MASK since carries from those bits will
8646 affect the bits we are interested in. */
8651 /* If X is (minus C Y) where C's least set bit is larger than any bit
8652 in the mask, then we may replace with (neg Y). */
8653 if (CONST_INT_P (XEXP (x
, 0))
8654 && least_bit_hwi (UINTVAL (XEXP (x
, 0))) > mask
)
8656 x
= simplify_gen_unary (NEG
, GET_MODE (x
), XEXP (x
, 1),
8658 return force_to_mode (x
, mode
, mask
, next_select
);
8661 /* Similarly, if C contains every bit in the fuller_mask, then we may
8662 replace with (not Y). */
8663 if (CONST_INT_P (XEXP (x
, 0))
8664 && ((UINTVAL (XEXP (x
, 0)) | fuller_mask
) == UINTVAL (XEXP (x
, 0))))
8666 x
= simplify_gen_unary (NOT
, GET_MODE (x
),
8667 XEXP (x
, 1), GET_MODE (x
));
8668 return force_to_mode (x
, mode
, mask
, next_select
);
8676 /* If X is (ior (lshiftrt FOO C1) C2), try to commute the IOR and
8677 LSHIFTRT so we end up with an (and (lshiftrt (ior ...) ...) ...)
8678 operation which may be a bitfield extraction. Ensure that the
8679 constant we form is not wider than the mode of X. */
8681 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
8682 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
8683 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
8684 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
8685 && CONST_INT_P (XEXP (x
, 1))
8686 && ((INTVAL (XEXP (XEXP (x
, 0), 1))
8687 + floor_log2 (INTVAL (XEXP (x
, 1))))
8688 < GET_MODE_PRECISION (GET_MODE (x
)))
8689 && (UINTVAL (XEXP (x
, 1))
8690 & ~nonzero_bits (XEXP (x
, 0), GET_MODE (x
))) == 0)
8692 temp
= gen_int_mode ((INTVAL (XEXP (x
, 1)) & mask
)
8693 << INTVAL (XEXP (XEXP (x
, 0), 1)),
8695 temp
= simplify_gen_binary (GET_CODE (x
), GET_MODE (x
),
8696 XEXP (XEXP (x
, 0), 0), temp
);
8697 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
), temp
,
8698 XEXP (XEXP (x
, 0), 1));
8699 return force_to_mode (x
, mode
, mask
, next_select
);
8703 /* For most binary operations, just propagate into the operation and
8704 change the mode if we have an operation of that mode. */
8706 op0
= force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8707 op1
= force_to_mode (XEXP (x
, 1), mode
, mask
, next_select
);
8709 /* If we ended up truncating both operands, truncate the result of the
8710 operation instead. */
8711 if (GET_CODE (op0
) == TRUNCATE
8712 && GET_CODE (op1
) == TRUNCATE
)
8714 op0
= XEXP (op0
, 0);
8715 op1
= XEXP (op1
, 0);
8718 op0
= gen_lowpart_or_truncate (op_mode
, op0
);
8719 op1
= gen_lowpart_or_truncate (op_mode
, op1
);
8721 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8722 x
= simplify_gen_binary (code
, op_mode
, op0
, op1
);
8726 /* For left shifts, do the same, but just for the first operand.
8727 However, we cannot do anything with shifts where we cannot
8728 guarantee that the counts are smaller than the size of the mode
8729 because such a count will have a different meaning in a
8732 if (! (CONST_INT_P (XEXP (x
, 1))
8733 && INTVAL (XEXP (x
, 1)) >= 0
8734 && INTVAL (XEXP (x
, 1)) < GET_MODE_PRECISION (mode
))
8735 && ! (GET_MODE (XEXP (x
, 1)) != VOIDmode
8736 && (nonzero_bits (XEXP (x
, 1), GET_MODE (XEXP (x
, 1)))
8737 < (unsigned HOST_WIDE_INT
) GET_MODE_PRECISION (mode
))))
8740 /* If the shift count is a constant and we can do arithmetic in
8741 the mode of the shift, refine which bits we need. Otherwise, use the
8742 conservative form of the mask. */
8743 if (CONST_INT_P (XEXP (x
, 1))
8744 && INTVAL (XEXP (x
, 1)) >= 0
8745 && INTVAL (XEXP (x
, 1)) < GET_MODE_PRECISION (op_mode
)
8746 && HWI_COMPUTABLE_MODE_P (op_mode
))
8747 mask
>>= INTVAL (XEXP (x
, 1));
8751 op0
= gen_lowpart_or_truncate (op_mode
,
8752 force_to_mode (XEXP (x
, 0), op_mode
,
8753 mask
, next_select
));
8755 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
8756 x
= simplify_gen_binary (code
, op_mode
, op0
, XEXP (x
, 1));
8760 /* Here we can only do something if the shift count is a constant,
8761 this shift constant is valid for the host, and we can do arithmetic
8764 if (CONST_INT_P (XEXP (x
, 1))
8765 && INTVAL (XEXP (x
, 1)) >= 0
8766 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
8767 && HWI_COMPUTABLE_MODE_P (op_mode
))
8769 rtx inner
= XEXP (x
, 0);
8770 unsigned HOST_WIDE_INT inner_mask
;
8772 /* Select the mask of the bits we need for the shift operand. */
8773 inner_mask
= mask
<< INTVAL (XEXP (x
, 1));
8775 /* We can only change the mode of the shift if we can do arithmetic
8776 in the mode of the shift and INNER_MASK is no wider than the
8777 width of X's mode. */
8778 if ((inner_mask
& ~GET_MODE_MASK (GET_MODE (x
))) != 0)
8779 op_mode
= GET_MODE (x
);
8781 inner
= force_to_mode (inner
, op_mode
, inner_mask
, next_select
);
8783 if (GET_MODE (x
) != op_mode
|| inner
!= XEXP (x
, 0))
8784 x
= simplify_gen_binary (LSHIFTRT
, op_mode
, inner
, XEXP (x
, 1));
8787 /* If we have (and (lshiftrt FOO C1) C2) where the combination of the
8788 shift and AND produces only copies of the sign bit (C2 is one less
8789 than a power of two), we can do this with just a shift. */
8791 if (GET_CODE (x
) == LSHIFTRT
8792 && CONST_INT_P (XEXP (x
, 1))
8793 /* The shift puts one of the sign bit copies in the least significant
8795 && ((INTVAL (XEXP (x
, 1))
8796 + num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0))))
8797 >= GET_MODE_PRECISION (GET_MODE (x
)))
8798 && pow2p_hwi (mask
+ 1)
8799 /* Number of bits left after the shift must be more than the mask
8801 && ((INTVAL (XEXP (x
, 1)) + exact_log2 (mask
+ 1))
8802 <= GET_MODE_PRECISION (GET_MODE (x
)))
8803 /* Must be more sign bit copies than the mask needs. */
8804 && ((int) num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
8805 >= exact_log2 (mask
+ 1)))
8806 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
8807 GEN_INT (GET_MODE_PRECISION (GET_MODE (x
))
8808 - exact_log2 (mask
+ 1)));
8813 /* If we are just looking for the sign bit, we don't need this shift at
8814 all, even if it has a variable count. */
8815 if (val_signbit_p (GET_MODE (x
), mask
))
8816 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8818 /* If this is a shift by a constant, get a mask that contains those bits
8819 that are not copies of the sign bit. We then have two cases: If
8820 MASK only includes those bits, this can be a logical shift, which may
8821 allow simplifications. If MASK is a single-bit field not within
8822 those bits, we are requesting a copy of the sign bit and hence can
8823 shift the sign bit to the appropriate location. */
8825 if (CONST_INT_P (XEXP (x
, 1)) && INTVAL (XEXP (x
, 1)) >= 0
8826 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
)
8830 /* If the considered data is wider than HOST_WIDE_INT, we can't
8831 represent a mask for all its bits in a single scalar.
8832 But we only care about the lower bits, so calculate these. */
8834 if (GET_MODE_PRECISION (GET_MODE (x
)) > HOST_BITS_PER_WIDE_INT
)
8836 nonzero
= HOST_WIDE_INT_M1U
;
8838 /* GET_MODE_PRECISION (GET_MODE (x)) - INTVAL (XEXP (x, 1))
8839 is the number of bits a full-width mask would have set.
8840 We need only shift if these are fewer than nonzero can
8841 hold. If not, we must keep all bits set in nonzero. */
8843 if (GET_MODE_PRECISION (GET_MODE (x
)) - INTVAL (XEXP (x
, 1))
8844 < HOST_BITS_PER_WIDE_INT
)
8845 nonzero
>>= INTVAL (XEXP (x
, 1))
8846 + HOST_BITS_PER_WIDE_INT
8847 - GET_MODE_PRECISION (GET_MODE (x
)) ;
8851 nonzero
= GET_MODE_MASK (GET_MODE (x
));
8852 nonzero
>>= INTVAL (XEXP (x
, 1));
8855 if ((mask
& ~nonzero
) == 0)
8857 x
= simplify_shift_const (NULL_RTX
, LSHIFTRT
, GET_MODE (x
),
8858 XEXP (x
, 0), INTVAL (XEXP (x
, 1)));
8859 if (GET_CODE (x
) != ASHIFTRT
)
8860 return force_to_mode (x
, mode
, mask
, next_select
);
8863 else if ((i
= exact_log2 (mask
)) >= 0)
8865 x
= simplify_shift_const
8866 (NULL_RTX
, LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
8867 GET_MODE_PRECISION (GET_MODE (x
)) - 1 - i
);
8869 if (GET_CODE (x
) != ASHIFTRT
)
8870 return force_to_mode (x
, mode
, mask
, next_select
);
8874 /* If MASK is 1, convert this to an LSHIFTRT. This can be done
8875 even if the shift count isn't a constant. */
8877 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
),
8878 XEXP (x
, 0), XEXP (x
, 1));
8882 /* If this is a zero- or sign-extension operation that just affects bits
8883 we don't care about, remove it. Be sure the call above returned
8884 something that is still a shift. */
8886 if ((GET_CODE (x
) == LSHIFTRT
|| GET_CODE (x
) == ASHIFTRT
)
8887 && CONST_INT_P (XEXP (x
, 1))
8888 && INTVAL (XEXP (x
, 1)) >= 0
8889 && (INTVAL (XEXP (x
, 1))
8890 <= GET_MODE_PRECISION (GET_MODE (x
)) - (floor_log2 (mask
) + 1))
8891 && GET_CODE (XEXP (x
, 0)) == ASHIFT
8892 && XEXP (XEXP (x
, 0), 1) == XEXP (x
, 1))
8893 return force_to_mode (XEXP (XEXP (x
, 0), 0), mode
, mask
,
8900 /* If the shift count is constant and we can do computations
8901 in the mode of X, compute where the bits we care about are.
8902 Otherwise, we can't do anything. Don't change the mode of
8903 the shift or propagate MODE into the shift, though. */
8904 if (CONST_INT_P (XEXP (x
, 1))
8905 && INTVAL (XEXP (x
, 1)) >= 0)
8907 temp
= simplify_binary_operation (code
== ROTATE
? ROTATERT
: ROTATE
,
8909 gen_int_mode (mask
, GET_MODE (x
)),
8911 if (temp
&& CONST_INT_P (temp
))
8912 x
= simplify_gen_binary (code
, GET_MODE (x
),
8913 force_to_mode (XEXP (x
, 0), GET_MODE (x
),
8914 INTVAL (temp
), next_select
),
8920 /* If we just want the low-order bit, the NEG isn't needed since it
8921 won't change the low-order bit. */
8923 return force_to_mode (XEXP (x
, 0), mode
, mask
, just_select
);
8925 /* We need any bits less significant than the most significant bit in
8926 MASK since carries from those bits will affect the bits we are
8932 /* (not FOO) is (xor FOO CONST), so if FOO is an LSHIFTRT, we can do the
8933 same as the XOR case above. Ensure that the constant we form is not
8934 wider than the mode of X. */
8936 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
8937 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
8938 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
8939 && (INTVAL (XEXP (XEXP (x
, 0), 1)) + floor_log2 (mask
)
8940 < GET_MODE_PRECISION (GET_MODE (x
)))
8941 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
8943 temp
= gen_int_mode (mask
<< INTVAL (XEXP (XEXP (x
, 0), 1)),
8945 temp
= simplify_gen_binary (XOR
, GET_MODE (x
),
8946 XEXP (XEXP (x
, 0), 0), temp
);
8947 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
),
8948 temp
, XEXP (XEXP (x
, 0), 1));
8950 return force_to_mode (x
, mode
, mask
, next_select
);
8953 /* (and (not FOO) CONST) is (not (or FOO (not CONST))), so we must
8954 use the full mask inside the NOT. */
8958 op0
= gen_lowpart_or_truncate (op_mode
,
8959 force_to_mode (XEXP (x
, 0), mode
, mask
,
8961 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
8962 x
= simplify_gen_unary (code
, op_mode
, op0
, op_mode
);
8966 /* (and (ne FOO 0) CONST) can be (and FOO CONST) if CONST is included
8967 in STORE_FLAG_VALUE and FOO has a single bit that might be nonzero,
8968 which is equal to STORE_FLAG_VALUE. */
8969 if ((mask
& ~STORE_FLAG_VALUE
) == 0
8970 && XEXP (x
, 1) == const0_rtx
8971 && GET_MODE (XEXP (x
, 0)) == mode
8972 && pow2p_hwi (nonzero_bits (XEXP (x
, 0), mode
))
8973 && (nonzero_bits (XEXP (x
, 0), mode
)
8974 == (unsigned HOST_WIDE_INT
) STORE_FLAG_VALUE
))
8975 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8980 /* We have no way of knowing if the IF_THEN_ELSE can itself be
8981 written in a narrower mode. We play it safe and do not do so. */
8983 op0
= gen_lowpart_or_truncate (GET_MODE (x
),
8984 force_to_mode (XEXP (x
, 1), mode
,
8985 mask
, next_select
));
8986 op1
= gen_lowpart_or_truncate (GET_MODE (x
),
8987 force_to_mode (XEXP (x
, 2), mode
,
8988 mask
, next_select
));
8989 if (op0
!= XEXP (x
, 1) || op1
!= XEXP (x
, 2))
8990 x
= simplify_gen_ternary (IF_THEN_ELSE
, GET_MODE (x
),
8991 GET_MODE (XEXP (x
, 0)), XEXP (x
, 0),
8999 /* Ensure we return a value of the proper mode. */
9000 return gen_lowpart_or_truncate (mode
, x
);
9003 /* Return nonzero if X is an expression that has one of two values depending on
9004 whether some other value is zero or nonzero. In that case, we return the
9005 value that is being tested, *PTRUE is set to the value if the rtx being
9006 returned has a nonzero value, and *PFALSE is set to the other alternative.
9008 If we return zero, we set *PTRUE and *PFALSE to X. */
9011 if_then_else_cond (rtx x
, rtx
*ptrue
, rtx
*pfalse
)
9013 machine_mode mode
= GET_MODE (x
);
9014 enum rtx_code code
= GET_CODE (x
);
9015 rtx cond0
, cond1
, true0
, true1
, false0
, false1
;
9016 unsigned HOST_WIDE_INT nz
;
9018 /* If we are comparing a value against zero, we are done. */
9019 if ((code
== NE
|| code
== EQ
)
9020 && XEXP (x
, 1) == const0_rtx
)
9022 *ptrue
= (code
== NE
) ? const_true_rtx
: const0_rtx
;
9023 *pfalse
= (code
== NE
) ? const0_rtx
: const_true_rtx
;
9027 /* If this is a unary operation whose operand has one of two values, apply
9028 our opcode to compute those values. */
9029 else if (UNARY_P (x
)
9030 && (cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
)) != 0)
9032 *ptrue
= simplify_gen_unary (code
, mode
, true0
, GET_MODE (XEXP (x
, 0)));
9033 *pfalse
= simplify_gen_unary (code
, mode
, false0
,
9034 GET_MODE (XEXP (x
, 0)));
9038 /* If this is a COMPARE, do nothing, since the IF_THEN_ELSE we would
9039 make can't possibly match and would suppress other optimizations. */
9040 else if (code
== COMPARE
)
9043 /* If this is a binary operation, see if either side has only one of two
9044 values. If either one does or if both do and they are conditional on
9045 the same value, compute the new true and false values. */
9046 else if (BINARY_P (x
))
9048 cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
);
9049 cond1
= if_then_else_cond (XEXP (x
, 1), &true1
, &false1
);
9051 if ((cond0
!= 0 || cond1
!= 0)
9052 && ! (cond0
!= 0 && cond1
!= 0 && ! rtx_equal_p (cond0
, cond1
)))
9054 /* If if_then_else_cond returned zero, then true/false are the
9055 same rtl. We must copy one of them to prevent invalid rtl
9058 true0
= copy_rtx (true0
);
9059 else if (cond1
== 0)
9060 true1
= copy_rtx (true1
);
9062 if (COMPARISON_P (x
))
9064 *ptrue
= simplify_gen_relational (code
, mode
, VOIDmode
,
9066 *pfalse
= simplify_gen_relational (code
, mode
, VOIDmode
,
9071 *ptrue
= simplify_gen_binary (code
, mode
, true0
, true1
);
9072 *pfalse
= simplify_gen_binary (code
, mode
, false0
, false1
);
9075 return cond0
? cond0
: cond1
;
9078 /* See if we have PLUS, IOR, XOR, MINUS or UMAX, where one of the
9079 operands is zero when the other is nonzero, and vice-versa,
9080 and STORE_FLAG_VALUE is 1 or -1. */
9082 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
9083 && (code
== PLUS
|| code
== IOR
|| code
== XOR
|| code
== MINUS
9085 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
9087 rtx op0
= XEXP (XEXP (x
, 0), 1);
9088 rtx op1
= XEXP (XEXP (x
, 1), 1);
9090 cond0
= XEXP (XEXP (x
, 0), 0);
9091 cond1
= XEXP (XEXP (x
, 1), 0);
9093 if (COMPARISON_P (cond0
)
9094 && COMPARISON_P (cond1
)
9095 && ((GET_CODE (cond0
) == reversed_comparison_code (cond1
, NULL
)
9096 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
9097 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
9098 || ((swap_condition (GET_CODE (cond0
))
9099 == reversed_comparison_code (cond1
, NULL
))
9100 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
9101 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
9102 && ! side_effects_p (x
))
9104 *ptrue
= simplify_gen_binary (MULT
, mode
, op0
, const_true_rtx
);
9105 *pfalse
= simplify_gen_binary (MULT
, mode
,
9107 ? simplify_gen_unary (NEG
, mode
,
9115 /* Similarly for MULT, AND and UMIN, except that for these the result
9117 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
9118 && (code
== MULT
|| code
== AND
|| code
== UMIN
)
9119 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
9121 cond0
= XEXP (XEXP (x
, 0), 0);
9122 cond1
= XEXP (XEXP (x
, 1), 0);
9124 if (COMPARISON_P (cond0
)
9125 && COMPARISON_P (cond1
)
9126 && ((GET_CODE (cond0
) == reversed_comparison_code (cond1
, NULL
)
9127 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
9128 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
9129 || ((swap_condition (GET_CODE (cond0
))
9130 == reversed_comparison_code (cond1
, NULL
))
9131 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
9132 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
9133 && ! side_effects_p (x
))
9135 *ptrue
= *pfalse
= const0_rtx
;
9141 else if (code
== IF_THEN_ELSE
)
9143 /* If we have IF_THEN_ELSE already, extract the condition and
9144 canonicalize it if it is NE or EQ. */
9145 cond0
= XEXP (x
, 0);
9146 *ptrue
= XEXP (x
, 1), *pfalse
= XEXP (x
, 2);
9147 if (GET_CODE (cond0
) == NE
&& XEXP (cond0
, 1) == const0_rtx
)
9148 return XEXP (cond0
, 0);
9149 else if (GET_CODE (cond0
) == EQ
&& XEXP (cond0
, 1) == const0_rtx
)
9151 *ptrue
= XEXP (x
, 2), *pfalse
= XEXP (x
, 1);
9152 return XEXP (cond0
, 0);
9158 /* If X is a SUBREG, we can narrow both the true and false values
9159 if the inner expression, if there is a condition. */
9160 else if (code
== SUBREG
9161 && 0 != (cond0
= if_then_else_cond (SUBREG_REG (x
),
9164 true0
= simplify_gen_subreg (mode
, true0
,
9165 GET_MODE (SUBREG_REG (x
)), SUBREG_BYTE (x
));
9166 false0
= simplify_gen_subreg (mode
, false0
,
9167 GET_MODE (SUBREG_REG (x
)), SUBREG_BYTE (x
));
9168 if (true0
&& false0
)
9176 /* If X is a constant, this isn't special and will cause confusions
9177 if we treat it as such. Likewise if it is equivalent to a constant. */
9178 else if (CONSTANT_P (x
)
9179 || ((cond0
= get_last_value (x
)) != 0 && CONSTANT_P (cond0
)))
9182 /* If we're in BImode, canonicalize on 0 and STORE_FLAG_VALUE, as that
9183 will be least confusing to the rest of the compiler. */
9184 else if (mode
== BImode
)
9186 *ptrue
= GEN_INT (STORE_FLAG_VALUE
), *pfalse
= const0_rtx
;
9190 /* If X is known to be either 0 or -1, those are the true and
9191 false values when testing X. */
9192 else if (x
== constm1_rtx
|| x
== const0_rtx
9193 || (mode
!= VOIDmode
&& mode
!= BLKmode
9194 && num_sign_bit_copies (x
, mode
) == GET_MODE_PRECISION (mode
)))
9196 *ptrue
= constm1_rtx
, *pfalse
= const0_rtx
;
9200 /* Likewise for 0 or a single bit. */
9201 else if (HWI_COMPUTABLE_MODE_P (mode
)
9202 && pow2p_hwi (nz
= nonzero_bits (x
, mode
)))
9204 *ptrue
= gen_int_mode (nz
, mode
), *pfalse
= const0_rtx
;
9208 /* Otherwise fail; show no condition with true and false values the same. */
9209 *ptrue
= *pfalse
= x
;
9213 /* Return the value of expression X given the fact that condition COND
9214 is known to be true when applied to REG as its first operand and VAL
9215 as its second. X is known to not be shared and so can be modified in
9218 We only handle the simplest cases, and specifically those cases that
9219 arise with IF_THEN_ELSE expressions. */
9222 known_cond (rtx x
, enum rtx_code cond
, rtx reg
, rtx val
)
9224 enum rtx_code code
= GET_CODE (x
);
9228 if (side_effects_p (x
))
9231 /* If either operand of the condition is a floating point value,
9232 then we have to avoid collapsing an EQ comparison. */
9234 && rtx_equal_p (x
, reg
)
9235 && ! FLOAT_MODE_P (GET_MODE (x
))
9236 && ! FLOAT_MODE_P (GET_MODE (val
)))
9239 if (cond
== UNEQ
&& rtx_equal_p (x
, reg
))
9242 /* If X is (abs REG) and we know something about REG's relationship
9243 with zero, we may be able to simplify this. */
9245 if (code
== ABS
&& rtx_equal_p (XEXP (x
, 0), reg
) && val
== const0_rtx
)
9248 case GE
: case GT
: case EQ
:
9251 return simplify_gen_unary (NEG
, GET_MODE (XEXP (x
, 0)),
9253 GET_MODE (XEXP (x
, 0)));
9258 /* The only other cases we handle are MIN, MAX, and comparisons if the
9259 operands are the same as REG and VAL. */
9261 else if (COMPARISON_P (x
) || COMMUTATIVE_ARITH_P (x
))
9263 if (rtx_equal_p (XEXP (x
, 0), val
))
9265 std::swap (val
, reg
);
9266 cond
= swap_condition (cond
);
9269 if (rtx_equal_p (XEXP (x
, 0), reg
) && rtx_equal_p (XEXP (x
, 1), val
))
9271 if (COMPARISON_P (x
))
9273 if (comparison_dominates_p (cond
, code
))
9274 return const_true_rtx
;
9276 code
= reversed_comparison_code (x
, NULL
);
9278 && comparison_dominates_p (cond
, code
))
9283 else if (code
== SMAX
|| code
== SMIN
9284 || code
== UMIN
|| code
== UMAX
)
9286 int unsignedp
= (code
== UMIN
|| code
== UMAX
);
9288 /* Do not reverse the condition when it is NE or EQ.
9289 This is because we cannot conclude anything about
9290 the value of 'SMAX (x, y)' when x is not equal to y,
9291 but we can when x equals y. */
9292 if ((code
== SMAX
|| code
== UMAX
)
9293 && ! (cond
== EQ
|| cond
== NE
))
9294 cond
= reverse_condition (cond
);
9299 return unsignedp
? x
: XEXP (x
, 1);
9301 return unsignedp
? x
: XEXP (x
, 0);
9303 return unsignedp
? XEXP (x
, 1) : x
;
9305 return unsignedp
? XEXP (x
, 0) : x
;
9312 else if (code
== SUBREG
)
9314 machine_mode inner_mode
= GET_MODE (SUBREG_REG (x
));
9315 rtx new_rtx
, r
= known_cond (SUBREG_REG (x
), cond
, reg
, val
);
9317 if (SUBREG_REG (x
) != r
)
9319 /* We must simplify subreg here, before we lose track of the
9320 original inner_mode. */
9321 new_rtx
= simplify_subreg (GET_MODE (x
), r
,
9322 inner_mode
, SUBREG_BYTE (x
));
9326 SUBST (SUBREG_REG (x
), r
);
9331 /* We don't have to handle SIGN_EXTEND here, because even in the
9332 case of replacing something with a modeless CONST_INT, a
9333 CONST_INT is already (supposed to be) a valid sign extension for
9334 its narrower mode, which implies it's already properly
9335 sign-extended for the wider mode. Now, for ZERO_EXTEND, the
9336 story is different. */
9337 else if (code
== ZERO_EXTEND
)
9339 machine_mode inner_mode
= GET_MODE (XEXP (x
, 0));
9340 rtx new_rtx
, r
= known_cond (XEXP (x
, 0), cond
, reg
, val
);
9342 if (XEXP (x
, 0) != r
)
9344 /* We must simplify the zero_extend here, before we lose
9345 track of the original inner_mode. */
9346 new_rtx
= simplify_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
9351 SUBST (XEXP (x
, 0), r
);
9357 fmt
= GET_RTX_FORMAT (code
);
9358 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
9361 SUBST (XEXP (x
, i
), known_cond (XEXP (x
, i
), cond
, reg
, val
));
9362 else if (fmt
[i
] == 'E')
9363 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
9364 SUBST (XVECEXP (x
, i
, j
), known_cond (XVECEXP (x
, i
, j
),
9371 /* See if X and Y are equal for the purposes of seeing if we can rewrite an
9372 assignment as a field assignment. */
9375 rtx_equal_for_field_assignment_p (rtx x
, rtx y
, bool widen_x
)
9377 if (widen_x
&& GET_MODE (x
) != GET_MODE (y
))
9379 if (GET_MODE_SIZE (GET_MODE (x
)) > GET_MODE_SIZE (GET_MODE (y
)))
9381 if (BYTES_BIG_ENDIAN
!= WORDS_BIG_ENDIAN
)
9383 /* For big endian, adjust the memory offset. */
9384 if (BYTES_BIG_ENDIAN
)
9385 x
= adjust_address_nv (x
, GET_MODE (y
),
9386 -subreg_lowpart_offset (GET_MODE (x
),
9389 x
= adjust_address_nv (x
, GET_MODE (y
), 0);
9392 if (x
== y
|| rtx_equal_p (x
, y
))
9395 if (x
== 0 || y
== 0 || GET_MODE (x
) != GET_MODE (y
))
9398 /* Check for a paradoxical SUBREG of a MEM compared with the MEM.
9399 Note that all SUBREGs of MEM are paradoxical; otherwise they
9400 would have been rewritten. */
9401 if (MEM_P (x
) && GET_CODE (y
) == SUBREG
9402 && MEM_P (SUBREG_REG (y
))
9403 && rtx_equal_p (SUBREG_REG (y
),
9404 gen_lowpart (GET_MODE (SUBREG_REG (y
)), x
)))
9407 if (MEM_P (y
) && GET_CODE (x
) == SUBREG
9408 && MEM_P (SUBREG_REG (x
))
9409 && rtx_equal_p (SUBREG_REG (x
),
9410 gen_lowpart (GET_MODE (SUBREG_REG (x
)), y
)))
9413 /* We used to see if get_last_value of X and Y were the same but that's
9414 not correct. In one direction, we'll cause the assignment to have
9415 the wrong destination and in the case, we'll import a register into this
9416 insn that might have already have been dead. So fail if none of the
9417 above cases are true. */
9421 /* See if X, a SET operation, can be rewritten as a bit-field assignment.
9422 Return that assignment if so.
9424 We only handle the most common cases. */
9427 make_field_assignment (rtx x
)
9429 rtx dest
= SET_DEST (x
);
9430 rtx src
= SET_SRC (x
);
9435 unsigned HOST_WIDE_INT len
;
9439 /* If SRC was (and (not (ashift (const_int 1) POS)) DEST), this is
9440 a clear of a one-bit field. We will have changed it to
9441 (and (rotate (const_int -2) POS) DEST), so check for that. Also check
9444 if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == ROTATE
9445 && CONST_INT_P (XEXP (XEXP (src
, 0), 0))
9446 && INTVAL (XEXP (XEXP (src
, 0), 0)) == -2
9447 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9449 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
9452 return gen_rtx_SET (assign
, const0_rtx
);
9456 if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == SUBREG
9457 && subreg_lowpart_p (XEXP (src
, 0))
9458 && (GET_MODE_SIZE (GET_MODE (XEXP (src
, 0)))
9459 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (src
, 0)))))
9460 && GET_CODE (SUBREG_REG (XEXP (src
, 0))) == ROTATE
9461 && CONST_INT_P (XEXP (SUBREG_REG (XEXP (src
, 0)), 0))
9462 && INTVAL (XEXP (SUBREG_REG (XEXP (src
, 0)), 0)) == -2
9463 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9465 assign
= make_extraction (VOIDmode
, dest
, 0,
9466 XEXP (SUBREG_REG (XEXP (src
, 0)), 1),
9469 return gen_rtx_SET (assign
, const0_rtx
);
9473 /* If SRC is (ior (ashift (const_int 1) POS) DEST), this is a set of a
9475 if (GET_CODE (src
) == IOR
&& GET_CODE (XEXP (src
, 0)) == ASHIFT
9476 && XEXP (XEXP (src
, 0), 0) == const1_rtx
9477 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9479 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
9482 return gen_rtx_SET (assign
, const1_rtx
);
9486 /* If DEST is already a field assignment, i.e. ZERO_EXTRACT, and the
9487 SRC is an AND with all bits of that field set, then we can discard
9489 if (GET_CODE (dest
) == ZERO_EXTRACT
9490 && CONST_INT_P (XEXP (dest
, 1))
9491 && GET_CODE (src
) == AND
9492 && CONST_INT_P (XEXP (src
, 1)))
9494 HOST_WIDE_INT width
= INTVAL (XEXP (dest
, 1));
9495 unsigned HOST_WIDE_INT and_mask
= INTVAL (XEXP (src
, 1));
9496 unsigned HOST_WIDE_INT ze_mask
;
9498 if (width
>= HOST_BITS_PER_WIDE_INT
)
9501 ze_mask
= ((unsigned HOST_WIDE_INT
)1 << width
) - 1;
9503 /* Complete overlap. We can remove the source AND. */
9504 if ((and_mask
& ze_mask
) == ze_mask
)
9505 return gen_rtx_SET (dest
, XEXP (src
, 0));
9507 /* Partial overlap. We can reduce the source AND. */
9508 if ((and_mask
& ze_mask
) != and_mask
)
9510 mode
= GET_MODE (src
);
9511 src
= gen_rtx_AND (mode
, XEXP (src
, 0),
9512 gen_int_mode (and_mask
& ze_mask
, mode
));
9513 return gen_rtx_SET (dest
, src
);
9517 /* The other case we handle is assignments into a constant-position
9518 field. They look like (ior/xor (and DEST C1) OTHER). If C1 represents
9519 a mask that has all one bits except for a group of zero bits and
9520 OTHER is known to have zeros where C1 has ones, this is such an
9521 assignment. Compute the position and length from C1. Shift OTHER
9522 to the appropriate position, force it to the required mode, and
9523 make the extraction. Check for the AND in both operands. */
9525 /* One or more SUBREGs might obscure the constant-position field
9526 assignment. The first one we are likely to encounter is an outer
9527 narrowing SUBREG, which we can just strip for the purposes of
9528 identifying the constant-field assignment. */
9529 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
))
9530 src
= SUBREG_REG (src
);
9532 if (GET_CODE (src
) != IOR
&& GET_CODE (src
) != XOR
)
9535 rhs
= expand_compound_operation (XEXP (src
, 0));
9536 lhs
= expand_compound_operation (XEXP (src
, 1));
9538 if (GET_CODE (rhs
) == AND
9539 && CONST_INT_P (XEXP (rhs
, 1))
9540 && rtx_equal_for_field_assignment_p (XEXP (rhs
, 0), dest
))
9541 c1
= INTVAL (XEXP (rhs
, 1)), other
= lhs
;
9542 /* The second SUBREG that might get in the way is a paradoxical
9543 SUBREG around the first operand of the AND. We want to
9544 pretend the operand is as wide as the destination here. We
9545 do this by adjusting the MEM to wider mode for the sole
9546 purpose of the call to rtx_equal_for_field_assignment_p. Also
9547 note this trick only works for MEMs. */
9548 else if (GET_CODE (rhs
) == AND
9549 && paradoxical_subreg_p (XEXP (rhs
, 0))
9550 && MEM_P (SUBREG_REG (XEXP (rhs
, 0)))
9551 && CONST_INT_P (XEXP (rhs
, 1))
9552 && rtx_equal_for_field_assignment_p (SUBREG_REG (XEXP (rhs
, 0)),
9554 c1
= INTVAL (XEXP (rhs
, 1)), other
= lhs
;
9555 else if (GET_CODE (lhs
) == AND
9556 && CONST_INT_P (XEXP (lhs
, 1))
9557 && rtx_equal_for_field_assignment_p (XEXP (lhs
, 0), dest
))
9558 c1
= INTVAL (XEXP (lhs
, 1)), other
= rhs
;
9559 /* The second SUBREG that might get in the way is a paradoxical
9560 SUBREG around the first operand of the AND. We want to
9561 pretend the operand is as wide as the destination here. We
9562 do this by adjusting the MEM to wider mode for the sole
9563 purpose of the call to rtx_equal_for_field_assignment_p. Also
9564 note this trick only works for MEMs. */
9565 else if (GET_CODE (lhs
) == AND
9566 && paradoxical_subreg_p (XEXP (lhs
, 0))
9567 && MEM_P (SUBREG_REG (XEXP (lhs
, 0)))
9568 && CONST_INT_P (XEXP (lhs
, 1))
9569 && rtx_equal_for_field_assignment_p (SUBREG_REG (XEXP (lhs
, 0)),
9571 c1
= INTVAL (XEXP (lhs
, 1)), other
= rhs
;
9575 pos
= get_pos_from_mask ((~c1
) & GET_MODE_MASK (GET_MODE (dest
)), &len
);
9576 if (pos
< 0 || pos
+ len
> GET_MODE_PRECISION (GET_MODE (dest
))
9577 || GET_MODE_PRECISION (GET_MODE (dest
)) > HOST_BITS_PER_WIDE_INT
9578 || (c1
& nonzero_bits (other
, GET_MODE (dest
))) != 0)
9581 assign
= make_extraction (VOIDmode
, dest
, pos
, NULL_RTX
, len
, 1, 1, 0);
9585 /* The mode to use for the source is the mode of the assignment, or of
9586 what is inside a possible STRICT_LOW_PART. */
9587 mode
= (GET_CODE (assign
) == STRICT_LOW_PART
9588 ? GET_MODE (XEXP (assign
, 0)) : GET_MODE (assign
));
9590 /* Shift OTHER right POS places and make it the source, restricting it
9591 to the proper length and mode. */
9593 src
= canon_reg_for_combine (simplify_shift_const (NULL_RTX
, LSHIFTRT
,
9597 src
= force_to_mode (src
, mode
,
9598 GET_MODE_PRECISION (mode
) >= HOST_BITS_PER_WIDE_INT
9600 : (HOST_WIDE_INT_1U
<< len
) - 1,
9603 /* If SRC is masked by an AND that does not make a difference in
9604 the value being stored, strip it. */
9605 if (GET_CODE (assign
) == ZERO_EXTRACT
9606 && CONST_INT_P (XEXP (assign
, 1))
9607 && INTVAL (XEXP (assign
, 1)) < HOST_BITS_PER_WIDE_INT
9608 && GET_CODE (src
) == AND
9609 && CONST_INT_P (XEXP (src
, 1))
9610 && UINTVAL (XEXP (src
, 1))
9611 == (HOST_WIDE_INT_1U
<< INTVAL (XEXP (assign
, 1))) - 1)
9612 src
= XEXP (src
, 0);
9614 return gen_rtx_SET (assign
, src
);
9617 /* See if X is of the form (+ (* a c) (* b c)) and convert to (* (+ a b) c)
9621 apply_distributive_law (rtx x
)
9623 enum rtx_code code
= GET_CODE (x
);
9624 enum rtx_code inner_code
;
9625 rtx lhs
, rhs
, other
;
9628 /* Distributivity is not true for floating point as it can change the
9629 value. So we don't do it unless -funsafe-math-optimizations. */
9630 if (FLOAT_MODE_P (GET_MODE (x
))
9631 && ! flag_unsafe_math_optimizations
)
9634 /* The outer operation can only be one of the following: */
9635 if (code
!= IOR
&& code
!= AND
&& code
!= XOR
9636 && code
!= PLUS
&& code
!= MINUS
)
9642 /* If either operand is a primitive we can't do anything, so get out
9644 if (OBJECT_P (lhs
) || OBJECT_P (rhs
))
9647 lhs
= expand_compound_operation (lhs
);
9648 rhs
= expand_compound_operation (rhs
);
9649 inner_code
= GET_CODE (lhs
);
9650 if (inner_code
!= GET_CODE (rhs
))
9653 /* See if the inner and outer operations distribute. */
9660 /* These all distribute except over PLUS. */
9661 if (code
== PLUS
|| code
== MINUS
)
9666 if (code
!= PLUS
&& code
!= MINUS
)
9671 /* This is also a multiply, so it distributes over everything. */
9674 /* This used to handle SUBREG, but this turned out to be counter-
9675 productive, since (subreg (op ...)) usually is not handled by
9676 insn patterns, and this "optimization" therefore transformed
9677 recognizable patterns into unrecognizable ones. Therefore the
9678 SUBREG case was removed from here.
9680 It is possible that distributing SUBREG over arithmetic operations
9681 leads to an intermediate result than can then be optimized further,
9682 e.g. by moving the outer SUBREG to the other side of a SET as done
9683 in simplify_set. This seems to have been the original intent of
9684 handling SUBREGs here.
9686 However, with current GCC this does not appear to actually happen,
9687 at least on major platforms. If some case is found where removing
9688 the SUBREG case here prevents follow-on optimizations, distributing
9689 SUBREGs ought to be re-added at that place, e.g. in simplify_set. */
9695 /* Set LHS and RHS to the inner operands (A and B in the example
9696 above) and set OTHER to the common operand (C in the example).
9697 There is only one way to do this unless the inner operation is
9699 if (COMMUTATIVE_ARITH_P (lhs
)
9700 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 0)))
9701 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 1);
9702 else if (COMMUTATIVE_ARITH_P (lhs
)
9703 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 1)))
9704 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 0);
9705 else if (COMMUTATIVE_ARITH_P (lhs
)
9706 && rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 0)))
9707 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 1);
9708 else if (rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 1)))
9709 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 0);
9713 /* Form the new inner operation, seeing if it simplifies first. */
9714 tem
= simplify_gen_binary (code
, GET_MODE (x
), lhs
, rhs
);
9716 /* There is one exception to the general way of distributing:
9717 (a | c) ^ (b | c) -> (a ^ b) & ~c */
9718 if (code
== XOR
&& inner_code
== IOR
)
9721 other
= simplify_gen_unary (NOT
, GET_MODE (x
), other
, GET_MODE (x
));
9724 /* We may be able to continuing distributing the result, so call
9725 ourselves recursively on the inner operation before forming the
9726 outer operation, which we return. */
9727 return simplify_gen_binary (inner_code
, GET_MODE (x
),
9728 apply_distributive_law (tem
), other
);
9731 /* See if X is of the form (* (+ A B) C), and if so convert to
9732 (+ (* A C) (* B C)) and try to simplify.
9734 Most of the time, this results in no change. However, if some of
9735 the operands are the same or inverses of each other, simplifications
9738 For example, (and (ior A B) (not B)) can occur as the result of
9739 expanding a bit field assignment. When we apply the distributive
9740 law to this, we get (ior (and (A (not B))) (and (B (not B)))),
9741 which then simplifies to (and (A (not B))).
9743 Note that no checks happen on the validity of applying the inverse
9744 distributive law. This is pointless since we can do it in the
9745 few places where this routine is called.
9747 N is the index of the term that is decomposed (the arithmetic operation,
9748 i.e. (+ A B) in the first example above). !N is the index of the term that
9749 is distributed, i.e. of C in the first example above. */
9751 distribute_and_simplify_rtx (rtx x
, int n
)
9754 enum rtx_code outer_code
, inner_code
;
9755 rtx decomposed
, distributed
, inner_op0
, inner_op1
, new_op0
, new_op1
, tmp
;
9757 /* Distributivity is not true for floating point as it can change the
9758 value. So we don't do it unless -funsafe-math-optimizations. */
9759 if (FLOAT_MODE_P (GET_MODE (x
))
9760 && ! flag_unsafe_math_optimizations
)
9763 decomposed
= XEXP (x
, n
);
9764 if (!ARITHMETIC_P (decomposed
))
9767 mode
= GET_MODE (x
);
9768 outer_code
= GET_CODE (x
);
9769 distributed
= XEXP (x
, !n
);
9771 inner_code
= GET_CODE (decomposed
);
9772 inner_op0
= XEXP (decomposed
, 0);
9773 inner_op1
= XEXP (decomposed
, 1);
9775 /* Special case (and (xor B C) (not A)), which is equivalent to
9776 (xor (ior A B) (ior A C)) */
9777 if (outer_code
== AND
&& inner_code
== XOR
&& GET_CODE (distributed
) == NOT
)
9779 distributed
= XEXP (distributed
, 0);
9785 /* Distribute the second term. */
9786 new_op0
= simplify_gen_binary (outer_code
, mode
, inner_op0
, distributed
);
9787 new_op1
= simplify_gen_binary (outer_code
, mode
, inner_op1
, distributed
);
9791 /* Distribute the first term. */
9792 new_op0
= simplify_gen_binary (outer_code
, mode
, distributed
, inner_op0
);
9793 new_op1
= simplify_gen_binary (outer_code
, mode
, distributed
, inner_op1
);
9796 tmp
= apply_distributive_law (simplify_gen_binary (inner_code
, mode
,
9798 if (GET_CODE (tmp
) != outer_code
9799 && (set_src_cost (tmp
, mode
, optimize_this_for_speed_p
)
9800 < set_src_cost (x
, mode
, optimize_this_for_speed_p
)))
9806 /* Simplify a logical `and' of VAROP with the constant CONSTOP, to be done
9807 in MODE. Return an equivalent form, if different from (and VAROP
9808 (const_int CONSTOP)). Otherwise, return NULL_RTX. */
9811 simplify_and_const_int_1 (machine_mode mode
, rtx varop
,
9812 unsigned HOST_WIDE_INT constop
)
9814 unsigned HOST_WIDE_INT nonzero
;
9815 unsigned HOST_WIDE_INT orig_constop
;
9820 orig_constop
= constop
;
9821 if (GET_CODE (varop
) == CLOBBER
)
9824 /* Simplify VAROP knowing that we will be only looking at some of the
9827 Note by passing in CONSTOP, we guarantee that the bits not set in
9828 CONSTOP are not significant and will never be examined. We must
9829 ensure that is the case by explicitly masking out those bits
9830 before returning. */
9831 varop
= force_to_mode (varop
, mode
, constop
, 0);
9833 /* If VAROP is a CLOBBER, we will fail so return it. */
9834 if (GET_CODE (varop
) == CLOBBER
)
9837 /* If VAROP is a CONST_INT, then we need to apply the mask in CONSTOP
9838 to VAROP and return the new constant. */
9839 if (CONST_INT_P (varop
))
9840 return gen_int_mode (INTVAL (varop
) & constop
, mode
);
9842 /* See what bits may be nonzero in VAROP. Unlike the general case of
9843 a call to nonzero_bits, here we don't care about bits outside
9846 nonzero
= nonzero_bits (varop
, mode
) & GET_MODE_MASK (mode
);
9848 /* Turn off all bits in the constant that are known to already be zero.
9849 Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS
9850 which is tested below. */
9854 /* If we don't have any bits left, return zero. */
9858 /* If VAROP is a NEG of something known to be zero or 1 and CONSTOP is
9859 a power of two, we can replace this with an ASHIFT. */
9860 if (GET_CODE (varop
) == NEG
&& nonzero_bits (XEXP (varop
, 0), mode
) == 1
9861 && (i
= exact_log2 (constop
)) >= 0)
9862 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (varop
, 0), i
);
9864 /* If VAROP is an IOR or XOR, apply the AND to both branches of the IOR
9865 or XOR, then try to apply the distributive law. This may eliminate
9866 operations if either branch can be simplified because of the AND.
9867 It may also make some cases more complex, but those cases probably
9868 won't match a pattern either with or without this. */
9870 if (GET_CODE (varop
) == IOR
|| GET_CODE (varop
) == XOR
)
9874 apply_distributive_law
9875 (simplify_gen_binary (GET_CODE (varop
), GET_MODE (varop
),
9876 simplify_and_const_int (NULL_RTX
,
9880 simplify_and_const_int (NULL_RTX
,
9885 /* If VAROP is PLUS, and the constant is a mask of low bits, distribute
9886 the AND and see if one of the operands simplifies to zero. If so, we
9887 may eliminate it. */
9889 if (GET_CODE (varop
) == PLUS
9890 && pow2p_hwi (constop
+ 1))
9894 o0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (varop
, 0), constop
);
9895 o1
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (varop
, 1), constop
);
9896 if (o0
== const0_rtx
)
9898 if (o1
== const0_rtx
)
9902 /* Make a SUBREG if necessary. If we can't make it, fail. */
9903 varop
= gen_lowpart (mode
, varop
);
9904 if (varop
== NULL_RTX
|| GET_CODE (varop
) == CLOBBER
)
9907 /* If we are only masking insignificant bits, return VAROP. */
9908 if (constop
== nonzero
)
9911 if (varop
== orig_varop
&& constop
== orig_constop
)
9914 /* Otherwise, return an AND. */
9915 return simplify_gen_binary (AND
, mode
, varop
, gen_int_mode (constop
, mode
));
9919 /* We have X, a logical `and' of VAROP with the constant CONSTOP, to be done
9922 Return an equivalent form, if different from X. Otherwise, return X. If
9923 X is zero, we are to always construct the equivalent form. */
9926 simplify_and_const_int (rtx x
, machine_mode mode
, rtx varop
,
9927 unsigned HOST_WIDE_INT constop
)
9929 rtx tem
= simplify_and_const_int_1 (mode
, varop
, constop
);
9934 x
= simplify_gen_binary (AND
, GET_MODE (varop
), varop
,
9935 gen_int_mode (constop
, mode
));
9936 if (GET_MODE (x
) != mode
)
9937 x
= gen_lowpart (mode
, x
);
9941 /* Given a REG, X, compute which bits in X can be nonzero.
9942 We don't care about bits outside of those defined in MODE.
9944 For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
9945 a shift, AND, or zero_extract, we can do better. */
9948 reg_nonzero_bits_for_combine (const_rtx x
, machine_mode mode
,
9949 const_rtx known_x ATTRIBUTE_UNUSED
,
9950 machine_mode known_mode ATTRIBUTE_UNUSED
,
9951 unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED
,
9952 unsigned HOST_WIDE_INT
*nonzero
)
9957 /* If X is a register whose nonzero bits value is current, use it.
9958 Otherwise, if X is a register whose value we can find, use that
9959 value. Otherwise, use the previously-computed global nonzero bits
9960 for this register. */
9962 rsp
= ®_stat
[REGNO (x
)];
9963 if (rsp
->last_set_value
!= 0
9964 && (rsp
->last_set_mode
== mode
9965 || (GET_MODE_CLASS (rsp
->last_set_mode
) == MODE_INT
9966 && GET_MODE_CLASS (mode
) == MODE_INT
))
9967 && ((rsp
->last_set_label
>= label_tick_ebb_start
9968 && rsp
->last_set_label
< label_tick
)
9969 || (rsp
->last_set_label
== label_tick
9970 && DF_INSN_LUID (rsp
->last_set
) < subst_low_luid
)
9971 || (REGNO (x
) >= FIRST_PSEUDO_REGISTER
9972 && REGNO (x
) < reg_n_sets_max
9973 && REG_N_SETS (REGNO (x
)) == 1
9975 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
9978 /* Note that, even if the precision of last_set_mode is lower than that
9979 of mode, record_value_for_reg invoked nonzero_bits on the register
9980 with nonzero_bits_mode (because last_set_mode is necessarily integral
9981 and HWI_COMPUTABLE_MODE_P in this case) so bits in nonzero_bits_mode
9982 are all valid, hence in mode too since nonzero_bits_mode is defined
9983 to the largest HWI_COMPUTABLE_MODE_P mode. */
9984 *nonzero
&= rsp
->last_set_nonzero_bits
;
9988 tem
= get_last_value (x
);
9991 if (SHORT_IMMEDIATES_SIGN_EXTEND
)
9992 tem
= sign_extend_short_imm (tem
, GET_MODE (x
),
9993 GET_MODE_PRECISION (mode
));
9998 if (nonzero_sign_valid
&& rsp
->nonzero_bits
)
10000 unsigned HOST_WIDE_INT mask
= rsp
->nonzero_bits
;
10002 if (GET_MODE_PRECISION (GET_MODE (x
)) < GET_MODE_PRECISION (mode
))
10003 /* We don't know anything about the upper bits. */
10004 mask
|= GET_MODE_MASK (mode
) ^ GET_MODE_MASK (GET_MODE (x
));
10012 /* Return the number of bits at the high-order end of X that are known to
10013 be equal to the sign bit. X will be used in mode MODE; if MODE is
10014 VOIDmode, X will be used in its own mode. The returned value will always
10015 be between 1 and the number of bits in MODE. */
10018 reg_num_sign_bit_copies_for_combine (const_rtx x
, machine_mode mode
,
10019 const_rtx known_x ATTRIBUTE_UNUSED
,
10020 machine_mode known_mode
10022 unsigned int known_ret ATTRIBUTE_UNUSED
,
10023 unsigned int *result
)
10026 reg_stat_type
*rsp
;
10028 rsp
= ®_stat
[REGNO (x
)];
10029 if (rsp
->last_set_value
!= 0
10030 && rsp
->last_set_mode
== mode
10031 && ((rsp
->last_set_label
>= label_tick_ebb_start
10032 && rsp
->last_set_label
< label_tick
)
10033 || (rsp
->last_set_label
== label_tick
10034 && DF_INSN_LUID (rsp
->last_set
) < subst_low_luid
)
10035 || (REGNO (x
) >= FIRST_PSEUDO_REGISTER
10036 && REGNO (x
) < reg_n_sets_max
10037 && REG_N_SETS (REGNO (x
)) == 1
10038 && !REGNO_REG_SET_P
10039 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
10042 *result
= rsp
->last_set_sign_bit_copies
;
10046 tem
= get_last_value (x
);
10050 if (nonzero_sign_valid
&& rsp
->sign_bit_copies
!= 0
10051 && GET_MODE_PRECISION (GET_MODE (x
)) == GET_MODE_PRECISION (mode
))
10052 *result
= rsp
->sign_bit_copies
;
10057 /* Return the number of "extended" bits there are in X, when interpreted
10058 as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For
10059 unsigned quantities, this is the number of high-order zero bits.
10060 For signed quantities, this is the number of copies of the sign bit
10061 minus 1. In both case, this function returns the number of "spare"
10062 bits. For example, if two quantities for which this function returns
10063 at least 1 are added, the addition is known not to overflow.
10065 This function will always return 0 unless called during combine, which
10066 implies that it must be called from a define_split. */
10069 extended_count (const_rtx x
, machine_mode mode
, int unsignedp
)
10071 if (nonzero_sign_valid
== 0)
10075 ? (HWI_COMPUTABLE_MODE_P (mode
)
10076 ? (unsigned int) (GET_MODE_PRECISION (mode
) - 1
10077 - floor_log2 (nonzero_bits (x
, mode
)))
10079 : num_sign_bit_copies (x
, mode
) - 1);
10082 /* This function is called from `simplify_shift_const' to merge two
10083 outer operations. Specifically, we have already found that we need
10084 to perform operation *POP0 with constant *PCONST0 at the outermost
10085 position. We would now like to also perform OP1 with constant CONST1
10086 (with *POP0 being done last).
10088 Return 1 if we can do the operation and update *POP0 and *PCONST0 with
10089 the resulting operation. *PCOMP_P is set to 1 if we would need to
10090 complement the innermost operand, otherwise it is unchanged.
10092 MODE is the mode in which the operation will be done. No bits outside
10093 the width of this mode matter. It is assumed that the width of this mode
10094 is smaller than or equal to HOST_BITS_PER_WIDE_INT.
10096 If *POP0 or OP1 are UNKNOWN, it means no operation is required. Only NEG, PLUS,
10097 IOR, XOR, and AND are supported. We may set *POP0 to SET if the proper
10098 result is simply *PCONST0.
10100 If the resulting operation cannot be expressed as one operation, we
10101 return 0 and do not change *POP0, *PCONST0, and *PCOMP_P. */
10104 merge_outer_ops (enum rtx_code
*pop0
, HOST_WIDE_INT
*pconst0
, enum rtx_code op1
, HOST_WIDE_INT const1
, machine_mode mode
, int *pcomp_p
)
10106 enum rtx_code op0
= *pop0
;
10107 HOST_WIDE_INT const0
= *pconst0
;
10109 const0
&= GET_MODE_MASK (mode
);
10110 const1
&= GET_MODE_MASK (mode
);
10112 /* If OP0 is an AND, clear unimportant bits in CONST1. */
10116 /* If OP0 or OP1 is UNKNOWN, this is easy. Similarly if they are the same or
10119 if (op1
== UNKNOWN
|| op0
== SET
)
10122 else if (op0
== UNKNOWN
)
10123 op0
= op1
, const0
= const1
;
10125 else if (op0
== op1
)
10149 /* Otherwise, if either is a PLUS or NEG, we can't do anything. */
10150 else if (op0
== PLUS
|| op1
== PLUS
|| op0
== NEG
|| op1
== NEG
)
10153 /* If the two constants aren't the same, we can't do anything. The
10154 remaining six cases can all be done. */
10155 else if (const0
!= const1
)
10163 /* (a & b) | b == b */
10165 else /* op1 == XOR */
10166 /* (a ^ b) | b == a | b */
10172 /* (a & b) ^ b == (~a) & b */
10173 op0
= AND
, *pcomp_p
= 1;
10174 else /* op1 == IOR */
10175 /* (a | b) ^ b == a & ~b */
10176 op0
= AND
, const0
= ~const0
;
10181 /* (a | b) & b == b */
10183 else /* op1 == XOR */
10184 /* (a ^ b) & b) == (~a) & b */
10191 /* Check for NO-OP cases. */
10192 const0
&= GET_MODE_MASK (mode
);
10194 && (op0
== IOR
|| op0
== XOR
|| op0
== PLUS
))
10196 else if (const0
== 0 && op0
== AND
)
10198 else if ((unsigned HOST_WIDE_INT
) const0
== GET_MODE_MASK (mode
)
10204 /* ??? Slightly redundant with the above mask, but not entirely.
10205 Moving this above means we'd have to sign-extend the mode mask
10206 for the final test. */
10207 if (op0
!= UNKNOWN
&& op0
!= NEG
)
10208 *pconst0
= trunc_int_for_mode (const0
, mode
);
10213 /* A helper to simplify_shift_const_1 to determine the mode we can perform
10214 the shift in. The original shift operation CODE is performed on OP in
10215 ORIG_MODE. Return the wider mode MODE if we can perform the operation
10216 in that mode. Return ORIG_MODE otherwise. We can also assume that the
10217 result of the shift is subject to operation OUTER_CODE with operand
10220 static machine_mode
10221 try_widen_shift_mode (enum rtx_code code
, rtx op
, int count
,
10222 machine_mode orig_mode
, machine_mode mode
,
10223 enum rtx_code outer_code
, HOST_WIDE_INT outer_const
)
10225 if (orig_mode
== mode
)
10227 gcc_assert (GET_MODE_PRECISION (mode
) > GET_MODE_PRECISION (orig_mode
));
10229 /* In general we can't perform in wider mode for right shift and rotate. */
10233 /* We can still widen if the bits brought in from the left are identical
10234 to the sign bit of ORIG_MODE. */
10235 if (num_sign_bit_copies (op
, mode
)
10236 > (unsigned) (GET_MODE_PRECISION (mode
)
10237 - GET_MODE_PRECISION (orig_mode
)))
10242 /* Similarly here but with zero bits. */
10243 if (HWI_COMPUTABLE_MODE_P (mode
)
10244 && (nonzero_bits (op
, mode
) & ~GET_MODE_MASK (orig_mode
)) == 0)
10247 /* We can also widen if the bits brought in will be masked off. This
10248 operation is performed in ORIG_MODE. */
10249 if (outer_code
== AND
)
10251 int care_bits
= low_bitmask_len (orig_mode
, outer_const
);
10254 && GET_MODE_PRECISION (orig_mode
) - care_bits
>= count
)
10263 gcc_unreachable ();
10270 /* Simplify a shift of VAROP by ORIG_COUNT bits. CODE says what kind
10271 of shift. The result of the shift is RESULT_MODE. Return NULL_RTX
10272 if we cannot simplify it. Otherwise, return a simplified value.
10274 The shift is normally computed in the widest mode we find in VAROP, as
10275 long as it isn't a different number of words than RESULT_MODE. Exceptions
10276 are ASHIFTRT and ROTATE, which are always done in their original mode. */
10279 simplify_shift_const_1 (enum rtx_code code
, machine_mode result_mode
,
10280 rtx varop
, int orig_count
)
10282 enum rtx_code orig_code
= code
;
10283 rtx orig_varop
= varop
;
10285 machine_mode mode
= result_mode
;
10286 machine_mode shift_mode
, tmode
;
10287 unsigned int mode_words
10288 = (GET_MODE_SIZE (mode
) + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
;
10289 /* We form (outer_op (code varop count) (outer_const)). */
10290 enum rtx_code outer_op
= UNKNOWN
;
10291 HOST_WIDE_INT outer_const
= 0;
10292 int complement_p
= 0;
10295 /* Make sure and truncate the "natural" shift on the way in. We don't
10296 want to do this inside the loop as it makes it more difficult to
10298 if (SHIFT_COUNT_TRUNCATED
)
10299 orig_count
&= GET_MODE_UNIT_BITSIZE (mode
) - 1;
10301 /* If we were given an invalid count, don't do anything except exactly
10302 what was requested. */
10304 if (orig_count
< 0 || orig_count
>= (int) GET_MODE_UNIT_PRECISION (mode
))
10307 count
= orig_count
;
10309 /* Unless one of the branches of the `if' in this loop does a `continue',
10310 we will `break' the loop after the `if'. */
10314 /* If we have an operand of (clobber (const_int 0)), fail. */
10315 if (GET_CODE (varop
) == CLOBBER
)
10318 /* Convert ROTATERT to ROTATE. */
10319 if (code
== ROTATERT
)
10321 unsigned int bitsize
= GET_MODE_UNIT_PRECISION (result_mode
);
10323 count
= bitsize
- count
;
10326 shift_mode
= try_widen_shift_mode (code
, varop
, count
, result_mode
,
10327 mode
, outer_op
, outer_const
);
10328 machine_mode shift_unit_mode
= GET_MODE_INNER (shift_mode
);
10330 /* Handle cases where the count is greater than the size of the mode
10331 minus 1. For ASHIFT, use the size minus one as the count (this can
10332 occur when simplifying (lshiftrt (ashiftrt ..))). For rotates,
10333 take the count modulo the size. For other shifts, the result is
10336 Since these shifts are being produced by the compiler by combining
10337 multiple operations, each of which are defined, we know what the
10338 result is supposed to be. */
10340 if (count
> (GET_MODE_PRECISION (shift_unit_mode
) - 1))
10342 if (code
== ASHIFTRT
)
10343 count
= GET_MODE_PRECISION (shift_unit_mode
) - 1;
10344 else if (code
== ROTATE
|| code
== ROTATERT
)
10345 count
%= GET_MODE_PRECISION (shift_unit_mode
);
10348 /* We can't simply return zero because there may be an
10350 varop
= const0_rtx
;
10356 /* If we discovered we had to complement VAROP, leave. Making a NOT
10357 here would cause an infinite loop. */
10361 if (shift_mode
== shift_unit_mode
)
10363 /* An arithmetic right shift of a quantity known to be -1 or 0
10365 if (code
== ASHIFTRT
10366 && (num_sign_bit_copies (varop
, shift_unit_mode
)
10367 == GET_MODE_PRECISION (shift_unit_mode
)))
10373 /* If we are doing an arithmetic right shift and discarding all but
10374 the sign bit copies, this is equivalent to doing a shift by the
10375 bitsize minus one. Convert it into that shift because it will
10376 often allow other simplifications. */
10378 if (code
== ASHIFTRT
10379 && (count
+ num_sign_bit_copies (varop
, shift_unit_mode
)
10380 >= GET_MODE_PRECISION (shift_unit_mode
)))
10381 count
= GET_MODE_PRECISION (shift_unit_mode
) - 1;
10383 /* We simplify the tests below and elsewhere by converting
10384 ASHIFTRT to LSHIFTRT if we know the sign bit is clear.
10385 `make_compound_operation' will convert it to an ASHIFTRT for
10386 those machines (such as VAX) that don't have an LSHIFTRT. */
10387 if (code
== ASHIFTRT
10388 && HWI_COMPUTABLE_MODE_P (shift_unit_mode
)
10389 && val_signbit_known_clear_p (shift_unit_mode
,
10390 nonzero_bits (varop
,
10394 if (((code
== LSHIFTRT
10395 && HWI_COMPUTABLE_MODE_P (shift_unit_mode
)
10396 && !(nonzero_bits (varop
, shift_unit_mode
) >> count
))
10398 && HWI_COMPUTABLE_MODE_P (shift_unit_mode
)
10399 && !((nonzero_bits (varop
, shift_unit_mode
) << count
)
10400 & GET_MODE_MASK (shift_unit_mode
))))
10401 && !side_effects_p (varop
))
10402 varop
= const0_rtx
;
10405 switch (GET_CODE (varop
))
10411 new_rtx
= expand_compound_operation (varop
);
10412 if (new_rtx
!= varop
)
10420 /* The following rules apply only to scalars. */
10421 if (shift_mode
!= shift_unit_mode
)
10424 /* If we have (xshiftrt (mem ...) C) and C is MODE_WIDTH
10425 minus the width of a smaller mode, we can do this with a
10426 SIGN_EXTEND or ZERO_EXTEND from the narrower memory location. */
10427 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10428 && ! mode_dependent_address_p (XEXP (varop
, 0),
10429 MEM_ADDR_SPACE (varop
))
10430 && ! MEM_VOLATILE_P (varop
)
10431 && (tmode
= mode_for_size (GET_MODE_BITSIZE (mode
) - count
,
10432 MODE_INT
, 1)) != BLKmode
)
10434 new_rtx
= adjust_address_nv (varop
, tmode
,
10435 BYTES_BIG_ENDIAN
? 0
10436 : count
/ BITS_PER_UNIT
);
10438 varop
= gen_rtx_fmt_e (code
== ASHIFTRT
? SIGN_EXTEND
10439 : ZERO_EXTEND
, mode
, new_rtx
);
10446 /* The following rules apply only to scalars. */
10447 if (shift_mode
!= shift_unit_mode
)
10450 /* If VAROP is a SUBREG, strip it as long as the inner operand has
10451 the same number of words as what we've seen so far. Then store
10452 the widest mode in MODE. */
10453 if (subreg_lowpart_p (varop
)
10454 && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
10455 > GET_MODE_SIZE (GET_MODE (varop
)))
10456 && (unsigned int) ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
10457 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
10459 && GET_MODE_CLASS (GET_MODE (varop
)) == MODE_INT
10460 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (varop
))) == MODE_INT
)
10462 varop
= SUBREG_REG (varop
);
10463 if (GET_MODE_SIZE (GET_MODE (varop
)) > GET_MODE_SIZE (mode
))
10464 mode
= GET_MODE (varop
);
10470 /* Some machines use MULT instead of ASHIFT because MULT
10471 is cheaper. But it is still better on those machines to
10472 merge two shifts into one. */
10473 if (CONST_INT_P (XEXP (varop
, 1))
10474 && exact_log2 (UINTVAL (XEXP (varop
, 1))) >= 0)
10477 = simplify_gen_binary (ASHIFT
, GET_MODE (varop
),
10479 GEN_INT (exact_log2 (
10480 UINTVAL (XEXP (varop
, 1)))));
10486 /* Similar, for when divides are cheaper. */
10487 if (CONST_INT_P (XEXP (varop
, 1))
10488 && exact_log2 (UINTVAL (XEXP (varop
, 1))) >= 0)
10491 = simplify_gen_binary (LSHIFTRT
, GET_MODE (varop
),
10493 GEN_INT (exact_log2 (
10494 UINTVAL (XEXP (varop
, 1)))));
10500 /* If we are extracting just the sign bit of an arithmetic
10501 right shift, that shift is not needed. However, the sign
10502 bit of a wider mode may be different from what would be
10503 interpreted as the sign bit in a narrower mode, so, if
10504 the result is narrower, don't discard the shift. */
10505 if (code
== LSHIFTRT
10506 && count
== (GET_MODE_UNIT_BITSIZE (result_mode
) - 1)
10507 && (GET_MODE_UNIT_BITSIZE (result_mode
)
10508 >= GET_MODE_UNIT_BITSIZE (GET_MODE (varop
))))
10510 varop
= XEXP (varop
, 0);
10519 /* The following rules apply only to scalars. */
10520 if (shift_mode
!= shift_unit_mode
)
10523 /* Here we have two nested shifts. The result is usually the
10524 AND of a new shift with a mask. We compute the result below. */
10525 if (CONST_INT_P (XEXP (varop
, 1))
10526 && INTVAL (XEXP (varop
, 1)) >= 0
10527 && INTVAL (XEXP (varop
, 1)) < GET_MODE_PRECISION (GET_MODE (varop
))
10528 && HWI_COMPUTABLE_MODE_P (result_mode
)
10529 && HWI_COMPUTABLE_MODE_P (mode
))
10531 enum rtx_code first_code
= GET_CODE (varop
);
10532 unsigned int first_count
= INTVAL (XEXP (varop
, 1));
10533 unsigned HOST_WIDE_INT mask
;
10536 /* We have one common special case. We can't do any merging if
10537 the inner code is an ASHIFTRT of a smaller mode. However, if
10538 we have (ashift:M1 (subreg:M1 (ashiftrt:M2 FOO C1) 0) C2)
10539 with C2 == GET_MODE_BITSIZE (M1) - GET_MODE_BITSIZE (M2),
10540 we can convert it to
10541 (ashiftrt:M1 (ashift:M1 (and:M1 (subreg:M1 FOO 0) C3) C2) C1).
10542 This simplifies certain SIGN_EXTEND operations. */
10543 if (code
== ASHIFT
&& first_code
== ASHIFTRT
10544 && count
== (GET_MODE_PRECISION (result_mode
)
10545 - GET_MODE_PRECISION (GET_MODE (varop
))))
10547 /* C3 has the low-order C1 bits zero. */
10549 mask
= GET_MODE_MASK (mode
)
10550 & ~((HOST_WIDE_INT_1U
<< first_count
) - 1);
10552 varop
= simplify_and_const_int (NULL_RTX
, result_mode
,
10553 XEXP (varop
, 0), mask
);
10554 varop
= simplify_shift_const (NULL_RTX
, ASHIFT
, result_mode
,
10556 count
= first_count
;
10561 /* If this was (ashiftrt (ashift foo C1) C2) and FOO has more
10562 than C1 high-order bits equal to the sign bit, we can convert
10563 this to either an ASHIFT or an ASHIFTRT depending on the
10566 We cannot do this if VAROP's mode is not SHIFT_MODE. */
10568 if (code
== ASHIFTRT
&& first_code
== ASHIFT
10569 && GET_MODE (varop
) == shift_mode
10570 && (num_sign_bit_copies (XEXP (varop
, 0), shift_mode
)
10573 varop
= XEXP (varop
, 0);
10574 count
-= first_count
;
10584 /* There are some cases we can't do. If CODE is ASHIFTRT,
10585 we can only do this if FIRST_CODE is also ASHIFTRT.
10587 We can't do the case when CODE is ROTATE and FIRST_CODE is
10590 If the mode of this shift is not the mode of the outer shift,
10591 we can't do this if either shift is a right shift or ROTATE.
10593 Finally, we can't do any of these if the mode is too wide
10594 unless the codes are the same.
10596 Handle the case where the shift codes are the same
10599 if (code
== first_code
)
10601 if (GET_MODE (varop
) != result_mode
10602 && (code
== ASHIFTRT
|| code
== LSHIFTRT
10603 || code
== ROTATE
))
10606 count
+= first_count
;
10607 varop
= XEXP (varop
, 0);
10611 if (code
== ASHIFTRT
10612 || (code
== ROTATE
&& first_code
== ASHIFTRT
)
10613 || GET_MODE_PRECISION (mode
) > HOST_BITS_PER_WIDE_INT
10614 || (GET_MODE (varop
) != result_mode
10615 && (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
10616 || first_code
== ROTATE
10617 || code
== ROTATE
)))
10620 /* To compute the mask to apply after the shift, shift the
10621 nonzero bits of the inner shift the same way the
10622 outer shift will. */
10624 mask_rtx
= gen_int_mode (nonzero_bits (varop
, GET_MODE (varop
)),
10628 = simplify_const_binary_operation (code
, result_mode
, mask_rtx
,
10631 /* Give up if we can't compute an outer operation to use. */
10633 || !CONST_INT_P (mask_rtx
)
10634 || ! merge_outer_ops (&outer_op
, &outer_const
, AND
,
10636 result_mode
, &complement_p
))
10639 /* If the shifts are in the same direction, we add the
10640 counts. Otherwise, we subtract them. */
10641 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10642 == (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
))
10643 count
+= first_count
;
10645 count
-= first_count
;
10647 /* If COUNT is positive, the new shift is usually CODE,
10648 except for the two exceptions below, in which case it is
10649 FIRST_CODE. If the count is negative, FIRST_CODE should
10652 && ((first_code
== ROTATE
&& code
== ASHIFT
)
10653 || (first_code
== ASHIFTRT
&& code
== LSHIFTRT
)))
10655 else if (count
< 0)
10656 code
= first_code
, count
= -count
;
10658 varop
= XEXP (varop
, 0);
10662 /* If we have (A << B << C) for any shift, we can convert this to
10663 (A << C << B). This wins if A is a constant. Only try this if
10664 B is not a constant. */
10666 else if (GET_CODE (varop
) == code
10667 && CONST_INT_P (XEXP (varop
, 0))
10668 && !CONST_INT_P (XEXP (varop
, 1)))
10670 /* For ((unsigned) (cstULL >> count)) >> cst2 we have to make
10671 sure the result will be masked. See PR70222. */
10672 if (code
== LSHIFTRT
10673 && mode
!= result_mode
10674 && !merge_outer_ops (&outer_op
, &outer_const
, AND
,
10675 GET_MODE_MASK (result_mode
)
10676 >> orig_count
, result_mode
,
10679 /* For ((int) (cstLL >> count)) >> cst2 just give up. Queuing
10680 up outer sign extension (often left and right shift) is
10681 hardly more efficient than the original. See PR70429. */
10682 if (code
== ASHIFTRT
&& mode
!= result_mode
)
10685 rtx new_rtx
= simplify_const_binary_operation (code
, mode
,
10688 varop
= gen_rtx_fmt_ee (code
, mode
, new_rtx
, XEXP (varop
, 1));
10695 /* The following rules apply only to scalars. */
10696 if (shift_mode
!= shift_unit_mode
)
10699 /* Make this fit the case below. */
10700 varop
= gen_rtx_XOR (mode
, XEXP (varop
, 0), constm1_rtx
);
10706 /* The following rules apply only to scalars. */
10707 if (shift_mode
!= shift_unit_mode
)
10710 /* If we have (xshiftrt (ior (plus X (const_int -1)) X) C)
10711 with C the size of VAROP - 1 and the shift is logical if
10712 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
10713 we have an (le X 0) operation. If we have an arithmetic shift
10714 and STORE_FLAG_VALUE is 1 or we have a logical shift with
10715 STORE_FLAG_VALUE of -1, we have a (neg (le X 0)) operation. */
10717 if (GET_CODE (varop
) == IOR
&& GET_CODE (XEXP (varop
, 0)) == PLUS
10718 && XEXP (XEXP (varop
, 0), 1) == constm1_rtx
10719 && (STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
10720 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
10721 && count
== (GET_MODE_PRECISION (GET_MODE (varop
)) - 1)
10722 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
10725 varop
= gen_rtx_LE (GET_MODE (varop
), XEXP (varop
, 1),
10728 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
10729 varop
= gen_rtx_NEG (GET_MODE (varop
), varop
);
10734 /* If we have (shift (logical)), move the logical to the outside
10735 to allow it to possibly combine with another logical and the
10736 shift to combine with another shift. This also canonicalizes to
10737 what a ZERO_EXTRACT looks like. Also, some machines have
10738 (and (shift)) insns. */
10740 if (CONST_INT_P (XEXP (varop
, 1))
10741 /* We can't do this if we have (ashiftrt (xor)) and the
10742 constant has its sign bit set in shift_mode with shift_mode
10743 wider than result_mode. */
10744 && !(code
== ASHIFTRT
&& GET_CODE (varop
) == XOR
10745 && result_mode
!= shift_mode
10746 && 0 > trunc_int_for_mode (INTVAL (XEXP (varop
, 1)),
10748 && (new_rtx
= simplify_const_binary_operation
10749 (code
, result_mode
,
10750 gen_int_mode (INTVAL (XEXP (varop
, 1)), result_mode
),
10751 GEN_INT (count
))) != 0
10752 && CONST_INT_P (new_rtx
)
10753 && merge_outer_ops (&outer_op
, &outer_const
, GET_CODE (varop
),
10754 INTVAL (new_rtx
), result_mode
, &complement_p
))
10756 varop
= XEXP (varop
, 0);
10760 /* If we can't do that, try to simplify the shift in each arm of the
10761 logical expression, make a new logical expression, and apply
10762 the inverse distributive law. This also can't be done for
10763 (ashiftrt (xor)) where we've widened the shift and the constant
10764 changes the sign bit. */
10765 if (CONST_INT_P (XEXP (varop
, 1))
10766 && !(code
== ASHIFTRT
&& GET_CODE (varop
) == XOR
10767 && result_mode
!= shift_mode
10768 && 0 > trunc_int_for_mode (INTVAL (XEXP (varop
, 1)),
10771 rtx lhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
10772 XEXP (varop
, 0), count
);
10773 rtx rhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
10774 XEXP (varop
, 1), count
);
10776 varop
= simplify_gen_binary (GET_CODE (varop
), shift_mode
,
10778 varop
= apply_distributive_law (varop
);
10786 /* The following rules apply only to scalars. */
10787 if (shift_mode
!= shift_unit_mode
)
10790 /* Convert (lshiftrt (eq FOO 0) C) to (xor FOO 1) if STORE_FLAG_VALUE
10791 says that the sign bit can be tested, FOO has mode MODE, C is
10792 GET_MODE_PRECISION (MODE) - 1, and FOO has only its low-order bit
10793 that may be nonzero. */
10794 if (code
== LSHIFTRT
10795 && XEXP (varop
, 1) == const0_rtx
10796 && GET_MODE (XEXP (varop
, 0)) == result_mode
10797 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10798 && HWI_COMPUTABLE_MODE_P (result_mode
)
10799 && STORE_FLAG_VALUE
== -1
10800 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
10801 && merge_outer_ops (&outer_op
, &outer_const
, XOR
, 1, result_mode
,
10804 varop
= XEXP (varop
, 0);
10811 /* The following rules apply only to scalars. */
10812 if (shift_mode
!= shift_unit_mode
)
10815 /* (lshiftrt (neg A) C) where A is either 0 or 1 and C is one less
10816 than the number of bits in the mode is equivalent to A. */
10817 if (code
== LSHIFTRT
10818 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10819 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1)
10821 varop
= XEXP (varop
, 0);
10826 /* NEG commutes with ASHIFT since it is multiplication. Move the
10827 NEG outside to allow shifts to combine. */
10829 && merge_outer_ops (&outer_op
, &outer_const
, NEG
, 0, result_mode
,
10832 varop
= XEXP (varop
, 0);
10838 /* The following rules apply only to scalars. */
10839 if (shift_mode
!= shift_unit_mode
)
10842 /* (lshiftrt (plus A -1) C) where A is either 0 or 1 and C
10843 is one less than the number of bits in the mode is
10844 equivalent to (xor A 1). */
10845 if (code
== LSHIFTRT
10846 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10847 && XEXP (varop
, 1) == constm1_rtx
10848 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
10849 && merge_outer_ops (&outer_op
, &outer_const
, XOR
, 1, result_mode
,
10853 varop
= XEXP (varop
, 0);
10857 /* If we have (xshiftrt (plus FOO BAR) C), and the only bits
10858 that might be nonzero in BAR are those being shifted out and those
10859 bits are known zero in FOO, we can replace the PLUS with FOO.
10860 Similarly in the other operand order. This code occurs when
10861 we are computing the size of a variable-size array. */
10863 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10864 && count
< HOST_BITS_PER_WIDE_INT
10865 && nonzero_bits (XEXP (varop
, 1), result_mode
) >> count
== 0
10866 && (nonzero_bits (XEXP (varop
, 1), result_mode
)
10867 & nonzero_bits (XEXP (varop
, 0), result_mode
)) == 0)
10869 varop
= XEXP (varop
, 0);
10872 else if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10873 && count
< HOST_BITS_PER_WIDE_INT
10874 && HWI_COMPUTABLE_MODE_P (result_mode
)
10875 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
10877 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
10878 & nonzero_bits (XEXP (varop
, 1),
10881 varop
= XEXP (varop
, 1);
10885 /* (ashift (plus foo C) N) is (plus (ashift foo N) C'). */
10887 && CONST_INT_P (XEXP (varop
, 1))
10888 && (new_rtx
= simplify_const_binary_operation
10889 (ASHIFT
, result_mode
,
10890 gen_int_mode (INTVAL (XEXP (varop
, 1)), result_mode
),
10891 GEN_INT (count
))) != 0
10892 && CONST_INT_P (new_rtx
)
10893 && merge_outer_ops (&outer_op
, &outer_const
, PLUS
,
10894 INTVAL (new_rtx
), result_mode
, &complement_p
))
10896 varop
= XEXP (varop
, 0);
10900 /* Check for 'PLUS signbit', which is the canonical form of 'XOR
10901 signbit', and attempt to change the PLUS to an XOR and move it to
10902 the outer operation as is done above in the AND/IOR/XOR case
10903 leg for shift(logical). See details in logical handling above
10904 for reasoning in doing so. */
10905 if (code
== LSHIFTRT
10906 && CONST_INT_P (XEXP (varop
, 1))
10907 && mode_signbit_p (result_mode
, XEXP (varop
, 1))
10908 && (new_rtx
= simplify_const_binary_operation
10909 (code
, result_mode
,
10910 gen_int_mode (INTVAL (XEXP (varop
, 1)), result_mode
),
10911 GEN_INT (count
))) != 0
10912 && CONST_INT_P (new_rtx
)
10913 && merge_outer_ops (&outer_op
, &outer_const
, XOR
,
10914 INTVAL (new_rtx
), result_mode
, &complement_p
))
10916 varop
= XEXP (varop
, 0);
10923 /* The following rules apply only to scalars. */
10924 if (shift_mode
!= shift_unit_mode
)
10927 /* If we have (xshiftrt (minus (ashiftrt X C)) X) C)
10928 with C the size of VAROP - 1 and the shift is logical if
10929 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
10930 we have a (gt X 0) operation. If the shift is arithmetic with
10931 STORE_FLAG_VALUE of 1 or logical with STORE_FLAG_VALUE == -1,
10932 we have a (neg (gt X 0)) operation. */
10934 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
10935 && GET_CODE (XEXP (varop
, 0)) == ASHIFTRT
10936 && count
== (GET_MODE_PRECISION (GET_MODE (varop
)) - 1)
10937 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
10938 && CONST_INT_P (XEXP (XEXP (varop
, 0), 1))
10939 && INTVAL (XEXP (XEXP (varop
, 0), 1)) == count
10940 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
10943 varop
= gen_rtx_GT (GET_MODE (varop
), XEXP (varop
, 1),
10946 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
10947 varop
= gen_rtx_NEG (GET_MODE (varop
), varop
);
10954 /* Change (lshiftrt (truncate (lshiftrt))) to (truncate (lshiftrt))
10955 if the truncate does not affect the value. */
10956 if (code
== LSHIFTRT
10957 && GET_CODE (XEXP (varop
, 0)) == LSHIFTRT
10958 && CONST_INT_P (XEXP (XEXP (varop
, 0), 1))
10959 && (INTVAL (XEXP (XEXP (varop
, 0), 1))
10960 >= (GET_MODE_UNIT_PRECISION (GET_MODE (XEXP (varop
, 0)))
10961 - GET_MODE_UNIT_PRECISION (GET_MODE (varop
)))))
10963 rtx varop_inner
= XEXP (varop
, 0);
10966 = gen_rtx_LSHIFTRT (GET_MODE (varop_inner
),
10967 XEXP (varop_inner
, 0),
10969 (count
+ INTVAL (XEXP (varop_inner
, 1))));
10970 varop
= gen_rtx_TRUNCATE (GET_MODE (varop
), varop_inner
);
10983 shift_mode
= try_widen_shift_mode (code
, varop
, count
, result_mode
, mode
,
10984 outer_op
, outer_const
);
10986 /* We have now finished analyzing the shift. The result should be
10987 a shift of type CODE with SHIFT_MODE shifting VAROP COUNT places. If
10988 OUTER_OP is non-UNKNOWN, it is an operation that needs to be applied
10989 to the result of the shift. OUTER_CONST is the relevant constant,
10990 but we must turn off all bits turned off in the shift. */
10992 if (outer_op
== UNKNOWN
10993 && orig_code
== code
&& orig_count
== count
10994 && varop
== orig_varop
10995 && shift_mode
== GET_MODE (varop
))
10998 /* Make a SUBREG if necessary. If we can't make it, fail. */
10999 varop
= gen_lowpart (shift_mode
, varop
);
11000 if (varop
== NULL_RTX
|| GET_CODE (varop
) == CLOBBER
)
11003 /* If we have an outer operation and we just made a shift, it is
11004 possible that we could have simplified the shift were it not
11005 for the outer operation. So try to do the simplification
11008 if (outer_op
!= UNKNOWN
)
11009 x
= simplify_shift_const_1 (code
, shift_mode
, varop
, count
);
11014 x
= simplify_gen_binary (code
, shift_mode
, varop
, GEN_INT (count
));
11016 /* If we were doing an LSHIFTRT in a wider mode than it was originally,
11017 turn off all the bits that the shift would have turned off. */
11018 if (orig_code
== LSHIFTRT
&& result_mode
!= shift_mode
)
11019 x
= simplify_and_const_int (NULL_RTX
, shift_mode
, x
,
11020 GET_MODE_MASK (result_mode
) >> orig_count
);
11022 /* Do the remainder of the processing in RESULT_MODE. */
11023 x
= gen_lowpart_or_truncate (result_mode
, x
);
11025 /* If COMPLEMENT_P is set, we have to complement X before doing the outer
11028 x
= simplify_gen_unary (NOT
, result_mode
, x
, result_mode
);
11030 if (outer_op
!= UNKNOWN
)
11032 if (GET_RTX_CLASS (outer_op
) != RTX_UNARY
11033 && GET_MODE_PRECISION (result_mode
) < HOST_BITS_PER_WIDE_INT
)
11034 outer_const
= trunc_int_for_mode (outer_const
, result_mode
);
11036 if (outer_op
== AND
)
11037 x
= simplify_and_const_int (NULL_RTX
, result_mode
, x
, outer_const
);
11038 else if (outer_op
== SET
)
11040 /* This means that we have determined that the result is
11041 equivalent to a constant. This should be rare. */
11042 if (!side_effects_p (x
))
11043 x
= GEN_INT (outer_const
);
11045 else if (GET_RTX_CLASS (outer_op
) == RTX_UNARY
)
11046 x
= simplify_gen_unary (outer_op
, result_mode
, x
, result_mode
);
11048 x
= simplify_gen_binary (outer_op
, result_mode
, x
,
11049 GEN_INT (outer_const
));
11055 /* Simplify a shift of VAROP by COUNT bits. CODE says what kind of shift.
11056 The result of the shift is RESULT_MODE. If we cannot simplify it,
11057 return X or, if it is NULL, synthesize the expression with
11058 simplify_gen_binary. Otherwise, return a simplified value.
11060 The shift is normally computed in the widest mode we find in VAROP, as
11061 long as it isn't a different number of words than RESULT_MODE. Exceptions
11062 are ASHIFTRT and ROTATE, which are always done in their original mode. */
11065 simplify_shift_const (rtx x
, enum rtx_code code
, machine_mode result_mode
,
11066 rtx varop
, int count
)
11068 rtx tem
= simplify_shift_const_1 (code
, result_mode
, varop
, count
);
11073 x
= simplify_gen_binary (code
, GET_MODE (varop
), varop
, GEN_INT (count
));
11074 if (GET_MODE (x
) != result_mode
)
11075 x
= gen_lowpart (result_mode
, x
);
11080 /* A subroutine of recog_for_combine. See there for arguments and
11084 recog_for_combine_1 (rtx
*pnewpat
, rtx_insn
*insn
, rtx
*pnotes
)
11086 rtx pat
= *pnewpat
;
11087 rtx pat_without_clobbers
;
11088 int insn_code_number
;
11089 int num_clobbers_to_add
= 0;
11091 rtx notes
= NULL_RTX
;
11092 rtx old_notes
, old_pat
;
11095 /* If PAT is a PARALLEL, check to see if it contains the CLOBBER
11096 we use to indicate that something didn't match. If we find such a
11097 thing, force rejection. */
11098 if (GET_CODE (pat
) == PARALLEL
)
11099 for (i
= XVECLEN (pat
, 0) - 1; i
>= 0; i
--)
11100 if (GET_CODE (XVECEXP (pat
, 0, i
)) == CLOBBER
11101 && XEXP (XVECEXP (pat
, 0, i
), 0) == const0_rtx
)
11104 old_pat
= PATTERN (insn
);
11105 old_notes
= REG_NOTES (insn
);
11106 PATTERN (insn
) = pat
;
11107 REG_NOTES (insn
) = NULL_RTX
;
11109 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
11110 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
11112 if (insn_code_number
< 0)
11113 fputs ("Failed to match this instruction:\n", dump_file
);
11115 fputs ("Successfully matched this instruction:\n", dump_file
);
11116 print_rtl_single (dump_file
, pat
);
11119 /* If it isn't, there is the possibility that we previously had an insn
11120 that clobbered some register as a side effect, but the combined
11121 insn doesn't need to do that. So try once more without the clobbers
11122 unless this represents an ASM insn. */
11124 if (insn_code_number
< 0 && ! check_asm_operands (pat
)
11125 && GET_CODE (pat
) == PARALLEL
)
11129 for (pos
= 0, i
= 0; i
< XVECLEN (pat
, 0); i
++)
11130 if (GET_CODE (XVECEXP (pat
, 0, i
)) != CLOBBER
)
11133 SUBST (XVECEXP (pat
, 0, pos
), XVECEXP (pat
, 0, i
));
11137 SUBST_INT (XVECLEN (pat
, 0), pos
);
11140 pat
= XVECEXP (pat
, 0, 0);
11142 PATTERN (insn
) = pat
;
11143 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
11144 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
11146 if (insn_code_number
< 0)
11147 fputs ("Failed to match this instruction:\n", dump_file
);
11149 fputs ("Successfully matched this instruction:\n", dump_file
);
11150 print_rtl_single (dump_file
, pat
);
11154 pat_without_clobbers
= pat
;
11156 PATTERN (insn
) = old_pat
;
11157 REG_NOTES (insn
) = old_notes
;
11159 /* Recognize all noop sets, these will be killed by followup pass. */
11160 if (insn_code_number
< 0 && GET_CODE (pat
) == SET
&& set_noop_p (pat
))
11161 insn_code_number
= NOOP_MOVE_INSN_CODE
, num_clobbers_to_add
= 0;
11163 /* If we had any clobbers to add, make a new pattern than contains
11164 them. Then check to make sure that all of them are dead. */
11165 if (num_clobbers_to_add
)
11167 rtx newpat
= gen_rtx_PARALLEL (VOIDmode
,
11168 rtvec_alloc (GET_CODE (pat
) == PARALLEL
11169 ? (XVECLEN (pat
, 0)
11170 + num_clobbers_to_add
)
11171 : num_clobbers_to_add
+ 1));
11173 if (GET_CODE (pat
) == PARALLEL
)
11174 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
11175 XVECEXP (newpat
, 0, i
) = XVECEXP (pat
, 0, i
);
11177 XVECEXP (newpat
, 0, 0) = pat
;
11179 add_clobbers (newpat
, insn_code_number
);
11181 for (i
= XVECLEN (newpat
, 0) - num_clobbers_to_add
;
11182 i
< XVECLEN (newpat
, 0); i
++)
11184 if (REG_P (XEXP (XVECEXP (newpat
, 0, i
), 0))
11185 && ! reg_dead_at_p (XEXP (XVECEXP (newpat
, 0, i
), 0), insn
))
11187 if (GET_CODE (XEXP (XVECEXP (newpat
, 0, i
), 0)) != SCRATCH
)
11189 gcc_assert (REG_P (XEXP (XVECEXP (newpat
, 0, i
), 0)));
11190 notes
= alloc_reg_note (REG_UNUSED
,
11191 XEXP (XVECEXP (newpat
, 0, i
), 0), notes
);
11197 if (insn_code_number
>= 0
11198 && insn_code_number
!= NOOP_MOVE_INSN_CODE
)
11200 old_pat
= PATTERN (insn
);
11201 old_notes
= REG_NOTES (insn
);
11202 old_icode
= INSN_CODE (insn
);
11203 PATTERN (insn
) = pat
;
11204 REG_NOTES (insn
) = notes
;
11206 /* Allow targets to reject combined insn. */
11207 if (!targetm
.legitimate_combined_insn (insn
))
11209 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
11210 fputs ("Instruction not appropriate for target.",
11213 /* Callers expect recog_for_combine to strip
11214 clobbers from the pattern on failure. */
11215 pat
= pat_without_clobbers
;
11218 insn_code_number
= -1;
11221 PATTERN (insn
) = old_pat
;
11222 REG_NOTES (insn
) = old_notes
;
11223 INSN_CODE (insn
) = old_icode
;
11229 return insn_code_number
;
11232 /* Change every ZERO_EXTRACT and ZERO_EXTEND of a SUBREG that can be
11233 expressed as an AND and maybe an LSHIFTRT, to that formulation.
11234 Return whether anything was so changed. */
11237 change_zero_ext (rtx pat
)
11239 bool changed
= false;
11240 rtx
*src
= &SET_SRC (pat
);
11242 subrtx_ptr_iterator::array_type array
;
11243 FOR_EACH_SUBRTX_PTR (iter
, array
, src
, NONCONST
)
11246 machine_mode mode
= GET_MODE (x
);
11249 if (GET_CODE (x
) == ZERO_EXTRACT
11250 && CONST_INT_P (XEXP (x
, 1))
11251 && CONST_INT_P (XEXP (x
, 2))
11252 && GET_MODE (XEXP (x
, 0)) == mode
)
11254 size
= INTVAL (XEXP (x
, 1));
11256 int start
= INTVAL (XEXP (x
, 2));
11257 if (BITS_BIG_ENDIAN
)
11258 start
= GET_MODE_PRECISION (mode
) - size
- start
;
11261 x
= gen_rtx_LSHIFTRT (mode
, XEXP (x
, 0), GEN_INT (start
));
11265 else if (GET_CODE (x
) == ZERO_EXTEND
11266 && SCALAR_INT_MODE_P (mode
)
11267 && GET_CODE (XEXP (x
, 0)) == SUBREG
11268 && SCALAR_INT_MODE_P (GET_MODE (SUBREG_REG (XEXP (x
, 0))))
11269 && !paradoxical_subreg_p (XEXP (x
, 0))
11270 && subreg_lowpart_p (XEXP (x
, 0)))
11272 size
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)));
11273 x
= SUBREG_REG (XEXP (x
, 0));
11274 if (GET_MODE (x
) != mode
)
11275 x
= gen_lowpart_SUBREG (mode
, x
);
11277 else if (GET_CODE (x
) == ZERO_EXTEND
11278 && SCALAR_INT_MODE_P (mode
)
11279 && REG_P (XEXP (x
, 0))
11280 && HARD_REGISTER_P (XEXP (x
, 0))
11281 && can_change_dest_mode (XEXP (x
, 0), 0, mode
))
11283 size
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)));
11284 x
= gen_rtx_REG (mode
, REGNO (XEXP (x
, 0)));
11289 wide_int mask
= wi::mask (size
, false, GET_MODE_PRECISION (mode
));
11290 x
= gen_rtx_AND (mode
, x
, immed_wide_int_const (mask
, mode
));
11297 FOR_EACH_SUBRTX_PTR (iter
, array
, src
, NONCONST
)
11298 maybe_swap_commutative_operands (**iter
);
11300 rtx
*dst
= &SET_DEST (pat
);
11301 if (GET_CODE (*dst
) == ZERO_EXTRACT
11302 && REG_P (XEXP (*dst
, 0))
11303 && CONST_INT_P (XEXP (*dst
, 1))
11304 && CONST_INT_P (XEXP (*dst
, 2)))
11306 rtx reg
= XEXP (*dst
, 0);
11307 int width
= INTVAL (XEXP (*dst
, 1));
11308 int offset
= INTVAL (XEXP (*dst
, 2));
11309 machine_mode mode
= GET_MODE (reg
);
11310 int reg_width
= GET_MODE_PRECISION (mode
);
11311 if (BITS_BIG_ENDIAN
)
11312 offset
= reg_width
- width
- offset
;
11315 wide_int mask
= wi::shifted_mask (offset
, width
, true, reg_width
);
11316 wide_int mask2
= wi::shifted_mask (offset
, width
, false, reg_width
);
11317 x
= gen_rtx_AND (mode
, reg
, immed_wide_int_const (mask
, mode
));
11319 y
= gen_rtx_ASHIFT (mode
, SET_SRC (pat
), GEN_INT (offset
));
11322 z
= gen_rtx_AND (mode
, y
, immed_wide_int_const (mask2
, mode
));
11323 w
= gen_rtx_IOR (mode
, x
, z
);
11324 SUBST (SET_DEST (pat
), reg
);
11325 SUBST (SET_SRC (pat
), w
);
11333 /* Like recog, but we receive the address of a pointer to a new pattern.
11334 We try to match the rtx that the pointer points to.
11335 If that fails, we may try to modify or replace the pattern,
11336 storing the replacement into the same pointer object.
11338 Modifications include deletion or addition of CLOBBERs. If the
11339 instruction will still not match, we change ZERO_EXTEND and ZERO_EXTRACT
11340 to the equivalent AND and perhaps LSHIFTRT patterns, and try with that
11341 (and undo if that fails).
11343 PNOTES is a pointer to a location where any REG_UNUSED notes added for
11344 the CLOBBERs are placed.
11346 The value is the final insn code from the pattern ultimately matched,
11350 recog_for_combine (rtx
*pnewpat
, rtx_insn
*insn
, rtx
*pnotes
)
11352 rtx pat
= *pnewpat
;
11353 int insn_code_number
= recog_for_combine_1 (pnewpat
, insn
, pnotes
);
11354 if (insn_code_number
>= 0 || check_asm_operands (pat
))
11355 return insn_code_number
;
11357 void *marker
= get_undo_marker ();
11358 bool changed
= false;
11360 if (GET_CODE (pat
) == SET
)
11361 changed
= change_zero_ext (pat
);
11362 else if (GET_CODE (pat
) == PARALLEL
)
11365 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
11367 rtx set
= XVECEXP (pat
, 0, i
);
11368 if (GET_CODE (set
) == SET
)
11369 changed
|= change_zero_ext (set
);
11375 insn_code_number
= recog_for_combine_1 (pnewpat
, insn
, pnotes
);
11377 if (insn_code_number
< 0)
11378 undo_to_marker (marker
);
11381 return insn_code_number
;
11384 /* Like gen_lowpart_general but for use by combine. In combine it
11385 is not possible to create any new pseudoregs. However, it is
11386 safe to create invalid memory addresses, because combine will
11387 try to recognize them and all they will do is make the combine
11390 If for some reason this cannot do its job, an rtx
11391 (clobber (const_int 0)) is returned.
11392 An insn containing that will not be recognized. */
11395 gen_lowpart_for_combine (machine_mode omode
, rtx x
)
11397 machine_mode imode
= GET_MODE (x
);
11398 unsigned int osize
= GET_MODE_SIZE (omode
);
11399 unsigned int isize
= GET_MODE_SIZE (imode
);
11402 if (omode
== imode
)
11405 /* We can only support MODE being wider than a word if X is a
11406 constant integer or has a mode the same size. */
11407 if (GET_MODE_SIZE (omode
) > UNITS_PER_WORD
11408 && ! (CONST_SCALAR_INT_P (x
) || isize
== osize
))
11411 /* X might be a paradoxical (subreg (mem)). In that case, gen_lowpart
11412 won't know what to do. So we will strip off the SUBREG here and
11413 process normally. */
11414 if (GET_CODE (x
) == SUBREG
&& MEM_P (SUBREG_REG (x
)))
11416 x
= SUBREG_REG (x
);
11418 /* For use in case we fall down into the address adjustments
11419 further below, we need to adjust the known mode and size of
11420 x; imode and isize, since we just adjusted x. */
11421 imode
= GET_MODE (x
);
11423 if (imode
== omode
)
11426 isize
= GET_MODE_SIZE (imode
);
11429 result
= gen_lowpart_common (omode
, x
);
11438 /* Refuse to work on a volatile memory ref or one with a mode-dependent
11440 if (MEM_VOLATILE_P (x
)
11441 || mode_dependent_address_p (XEXP (x
, 0), MEM_ADDR_SPACE (x
)))
11444 /* If we want to refer to something bigger than the original memref,
11445 generate a paradoxical subreg instead. That will force a reload
11446 of the original memref X. */
11448 return gen_rtx_SUBREG (omode
, x
, 0);
11450 if (WORDS_BIG_ENDIAN
)
11451 offset
= MAX (isize
, UNITS_PER_WORD
) - MAX (osize
, UNITS_PER_WORD
);
11453 /* Adjust the address so that the address-after-the-data is
11455 if (BYTES_BIG_ENDIAN
)
11456 offset
-= MIN (UNITS_PER_WORD
, osize
) - MIN (UNITS_PER_WORD
, isize
);
11458 return adjust_address_nv (x
, omode
, offset
);
11461 /* If X is a comparison operator, rewrite it in a new mode. This
11462 probably won't match, but may allow further simplifications. */
11463 else if (COMPARISON_P (x
))
11464 return gen_rtx_fmt_ee (GET_CODE (x
), omode
, XEXP (x
, 0), XEXP (x
, 1));
11466 /* If we couldn't simplify X any other way, just enclose it in a
11467 SUBREG. Normally, this SUBREG won't match, but some patterns may
11468 include an explicit SUBREG or we may simplify it further in combine. */
11473 if (imode
== VOIDmode
)
11475 imode
= int_mode_for_mode (omode
);
11476 x
= gen_lowpart_common (imode
, x
);
11480 res
= lowpart_subreg (omode
, x
, imode
);
11486 return gen_rtx_CLOBBER (omode
, const0_rtx
);
11489 /* Try to simplify a comparison between OP0 and a constant OP1,
11490 where CODE is the comparison code that will be tested, into a
11491 (CODE OP0 const0_rtx) form.
11493 The result is a possibly different comparison code to use.
11494 *POP1 may be updated. */
11496 static enum rtx_code
11497 simplify_compare_const (enum rtx_code code
, machine_mode mode
,
11498 rtx op0
, rtx
*pop1
)
11500 unsigned int mode_width
= GET_MODE_PRECISION (mode
);
11501 HOST_WIDE_INT const_op
= INTVAL (*pop1
);
11503 /* Get the constant we are comparing against and turn off all bits
11504 not on in our mode. */
11505 if (mode
!= VOIDmode
)
11506 const_op
= trunc_int_for_mode (const_op
, mode
);
11508 /* If we are comparing against a constant power of two and the value
11509 being compared can only have that single bit nonzero (e.g., it was
11510 `and'ed with that bit), we can replace this with a comparison
11513 && (code
== EQ
|| code
== NE
|| code
== GE
|| code
== GEU
11514 || code
== LT
|| code
== LTU
)
11515 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11516 && pow2p_hwi (const_op
& GET_MODE_MASK (mode
))
11517 && (nonzero_bits (op0
, mode
)
11518 == (unsigned HOST_WIDE_INT
) (const_op
& GET_MODE_MASK (mode
))))
11520 code
= (code
== EQ
|| code
== GE
|| code
== GEU
? NE
: EQ
);
11524 /* Similarly, if we are comparing a value known to be either -1 or
11525 0 with -1, change it to the opposite comparison against zero. */
11527 && (code
== EQ
|| code
== NE
|| code
== GT
|| code
== LE
11528 || code
== GEU
|| code
== LTU
)
11529 && num_sign_bit_copies (op0
, mode
) == mode_width
)
11531 code
= (code
== EQ
|| code
== LE
|| code
== GEU
? NE
: EQ
);
11535 /* Do some canonicalizations based on the comparison code. We prefer
11536 comparisons against zero and then prefer equality comparisons.
11537 If we can reduce the size of a constant, we will do that too. */
11541 /* < C is equivalent to <= (C - 1) */
11546 /* ... fall through to LE case below. */
11547 gcc_fallthrough ();
11553 /* <= C is equivalent to < (C + 1); we do this for C < 0 */
11560 /* If we are doing a <= 0 comparison on a value known to have
11561 a zero sign bit, we can replace this with == 0. */
11562 else if (const_op
== 0
11563 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11564 && (nonzero_bits (op0
, mode
)
11565 & (HOST_WIDE_INT_1U
<< (mode_width
- 1)))
11571 /* >= C is equivalent to > (C - 1). */
11576 /* ... fall through to GT below. */
11577 gcc_fallthrough ();
11583 /* > C is equivalent to >= (C + 1); we do this for C < 0. */
11590 /* If we are doing a > 0 comparison on a value known to have
11591 a zero sign bit, we can replace this with != 0. */
11592 else if (const_op
== 0
11593 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11594 && (nonzero_bits (op0
, mode
)
11595 & (HOST_WIDE_INT_1U
<< (mode_width
- 1)))
11601 /* < C is equivalent to <= (C - 1). */
11606 /* ... fall through ... */
11608 /* (unsigned) < 0x80000000 is equivalent to >= 0. */
11609 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11610 && (unsigned HOST_WIDE_INT
) const_op
11611 == HOST_WIDE_INT_1U
<< (mode_width
- 1))
11621 /* unsigned <= 0 is equivalent to == 0 */
11624 /* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
11625 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11626 && (unsigned HOST_WIDE_INT
) const_op
11627 == (HOST_WIDE_INT_1U
<< (mode_width
- 1)) - 1)
11635 /* >= C is equivalent to > (C - 1). */
11640 /* ... fall through ... */
11643 /* (unsigned) >= 0x80000000 is equivalent to < 0. */
11644 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11645 && (unsigned HOST_WIDE_INT
) const_op
11646 == HOST_WIDE_INT_1U
<< (mode_width
- 1))
11656 /* unsigned > 0 is equivalent to != 0 */
11659 /* (unsigned) > 0x7fffffff is equivalent to < 0. */
11660 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11661 && (unsigned HOST_WIDE_INT
) const_op
11662 == (HOST_WIDE_INT_1U
<< (mode_width
- 1)) - 1)
11673 *pop1
= GEN_INT (const_op
);
11677 /* Simplify a comparison between *POP0 and *POP1 where CODE is the
11678 comparison code that will be tested.
11680 The result is a possibly different comparison code to use. *POP0 and
11681 *POP1 may be updated.
11683 It is possible that we might detect that a comparison is either always
11684 true or always false. However, we do not perform general constant
11685 folding in combine, so this knowledge isn't useful. Such tautologies
11686 should have been detected earlier. Hence we ignore all such cases. */
11688 static enum rtx_code
11689 simplify_comparison (enum rtx_code code
, rtx
*pop0
, rtx
*pop1
)
11695 machine_mode mode
, tmode
;
11697 /* Try a few ways of applying the same transformation to both operands. */
11700 /* The test below this one won't handle SIGN_EXTENDs on these machines,
11701 so check specially. */
11702 if (!WORD_REGISTER_OPERATIONS
11703 && code
!= GTU
&& code
!= GEU
&& code
!= LTU
&& code
!= LEU
11704 && GET_CODE (op0
) == ASHIFTRT
&& GET_CODE (op1
) == ASHIFTRT
11705 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
11706 && GET_CODE (XEXP (op1
, 0)) == ASHIFT
11707 && GET_CODE (XEXP (XEXP (op0
, 0), 0)) == SUBREG
11708 && GET_CODE (XEXP (XEXP (op1
, 0), 0)) == SUBREG
11709 && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0)))
11710 == GET_MODE (SUBREG_REG (XEXP (XEXP (op1
, 0), 0))))
11711 && CONST_INT_P (XEXP (op0
, 1))
11712 && XEXP (op0
, 1) == XEXP (op1
, 1)
11713 && XEXP (op0
, 1) == XEXP (XEXP (op0
, 0), 1)
11714 && XEXP (op0
, 1) == XEXP (XEXP (op1
, 0), 1)
11715 && (INTVAL (XEXP (op0
, 1))
11716 == (GET_MODE_PRECISION (GET_MODE (op0
))
11717 - (GET_MODE_PRECISION
11718 (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0))))))))
11720 op0
= SUBREG_REG (XEXP (XEXP (op0
, 0), 0));
11721 op1
= SUBREG_REG (XEXP (XEXP (op1
, 0), 0));
11724 /* If both operands are the same constant shift, see if we can ignore the
11725 shift. We can if the shift is a rotate or if the bits shifted out of
11726 this shift are known to be zero for both inputs and if the type of
11727 comparison is compatible with the shift. */
11728 if (GET_CODE (op0
) == GET_CODE (op1
)
11729 && HWI_COMPUTABLE_MODE_P (GET_MODE (op0
))
11730 && ((GET_CODE (op0
) == ROTATE
&& (code
== NE
|| code
== EQ
))
11731 || ((GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFT
)
11732 && (code
!= GT
&& code
!= LT
&& code
!= GE
&& code
!= LE
))
11733 || (GET_CODE (op0
) == ASHIFTRT
11734 && (code
!= GTU
&& code
!= LTU
11735 && code
!= GEU
&& code
!= LEU
)))
11736 && CONST_INT_P (XEXP (op0
, 1))
11737 && INTVAL (XEXP (op0
, 1)) >= 0
11738 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
11739 && XEXP (op0
, 1) == XEXP (op1
, 1))
11741 machine_mode mode
= GET_MODE (op0
);
11742 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
11743 int shift_count
= INTVAL (XEXP (op0
, 1));
11745 if (GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFTRT
)
11746 mask
&= (mask
>> shift_count
) << shift_count
;
11747 else if (GET_CODE (op0
) == ASHIFT
)
11748 mask
= (mask
& (mask
<< shift_count
)) >> shift_count
;
11750 if ((nonzero_bits (XEXP (op0
, 0), mode
) & ~mask
) == 0
11751 && (nonzero_bits (XEXP (op1
, 0), mode
) & ~mask
) == 0)
11752 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0);
11757 /* If both operands are AND's of a paradoxical SUBREG by constant, the
11758 SUBREGs are of the same mode, and, in both cases, the AND would
11759 be redundant if the comparison was done in the narrower mode,
11760 do the comparison in the narrower mode (e.g., we are AND'ing with 1
11761 and the operand's possibly nonzero bits are 0xffffff01; in that case
11762 if we only care about QImode, we don't need the AND). This case
11763 occurs if the output mode of an scc insn is not SImode and
11764 STORE_FLAG_VALUE == 1 (e.g., the 386).
11766 Similarly, check for a case where the AND's are ZERO_EXTEND
11767 operations from some narrower mode even though a SUBREG is not
11770 else if (GET_CODE (op0
) == AND
&& GET_CODE (op1
) == AND
11771 && CONST_INT_P (XEXP (op0
, 1))
11772 && CONST_INT_P (XEXP (op1
, 1)))
11774 rtx inner_op0
= XEXP (op0
, 0);
11775 rtx inner_op1
= XEXP (op1
, 0);
11776 HOST_WIDE_INT c0
= INTVAL (XEXP (op0
, 1));
11777 HOST_WIDE_INT c1
= INTVAL (XEXP (op1
, 1));
11780 if (paradoxical_subreg_p (inner_op0
)
11781 && GET_CODE (inner_op1
) == SUBREG
11782 && (GET_MODE (SUBREG_REG (inner_op0
))
11783 == GET_MODE (SUBREG_REG (inner_op1
)))
11784 && (GET_MODE_PRECISION (GET_MODE (SUBREG_REG (inner_op0
)))
11785 <= HOST_BITS_PER_WIDE_INT
)
11786 && (0 == ((~c0
) & nonzero_bits (SUBREG_REG (inner_op0
),
11787 GET_MODE (SUBREG_REG (inner_op0
)))))
11788 && (0 == ((~c1
) & nonzero_bits (SUBREG_REG (inner_op1
),
11789 GET_MODE (SUBREG_REG (inner_op1
))))))
11791 op0
= SUBREG_REG (inner_op0
);
11792 op1
= SUBREG_REG (inner_op1
);
11794 /* The resulting comparison is always unsigned since we masked
11795 off the original sign bit. */
11796 code
= unsigned_condition (code
);
11802 for (tmode
= GET_CLASS_NARROWEST_MODE
11803 (GET_MODE_CLASS (GET_MODE (op0
)));
11804 tmode
!= GET_MODE (op0
); tmode
= GET_MODE_WIDER_MODE (tmode
))
11805 if ((unsigned HOST_WIDE_INT
) c0
== GET_MODE_MASK (tmode
))
11807 op0
= gen_lowpart_or_truncate (tmode
, inner_op0
);
11808 op1
= gen_lowpart_or_truncate (tmode
, inner_op1
);
11809 code
= unsigned_condition (code
);
11818 /* If both operands are NOT, we can strip off the outer operation
11819 and adjust the comparison code for swapped operands; similarly for
11820 NEG, except that this must be an equality comparison. */
11821 else if ((GET_CODE (op0
) == NOT
&& GET_CODE (op1
) == NOT
)
11822 || (GET_CODE (op0
) == NEG
&& GET_CODE (op1
) == NEG
11823 && (code
== EQ
|| code
== NE
)))
11824 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0), code
= swap_condition (code
);
11830 /* If the first operand is a constant, swap the operands and adjust the
11831 comparison code appropriately, but don't do this if the second operand
11832 is already a constant integer. */
11833 if (swap_commutative_operands_p (op0
, op1
))
11835 std::swap (op0
, op1
);
11836 code
= swap_condition (code
);
11839 /* We now enter a loop during which we will try to simplify the comparison.
11840 For the most part, we only are concerned with comparisons with zero,
11841 but some things may really be comparisons with zero but not start
11842 out looking that way. */
11844 while (CONST_INT_P (op1
))
11846 machine_mode mode
= GET_MODE (op0
);
11847 unsigned int mode_width
= GET_MODE_PRECISION (mode
);
11848 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
11849 int equality_comparison_p
;
11850 int sign_bit_comparison_p
;
11851 int unsigned_comparison_p
;
11852 HOST_WIDE_INT const_op
;
11854 /* We only want to handle integral modes. This catches VOIDmode,
11855 CCmode, and the floating-point modes. An exception is that we
11856 can handle VOIDmode if OP0 is a COMPARE or a comparison
11859 if (GET_MODE_CLASS (mode
) != MODE_INT
11860 && ! (mode
== VOIDmode
11861 && (GET_CODE (op0
) == COMPARE
|| COMPARISON_P (op0
))))
11864 /* Try to simplify the compare to constant, possibly changing the
11865 comparison op, and/or changing op1 to zero. */
11866 code
= simplify_compare_const (code
, mode
, op0
, &op1
);
11867 const_op
= INTVAL (op1
);
11869 /* Compute some predicates to simplify code below. */
11871 equality_comparison_p
= (code
== EQ
|| code
== NE
);
11872 sign_bit_comparison_p
= ((code
== LT
|| code
== GE
) && const_op
== 0);
11873 unsigned_comparison_p
= (code
== LTU
|| code
== LEU
|| code
== GTU
11876 /* If this is a sign bit comparison and we can do arithmetic in
11877 MODE, say that we will only be needing the sign bit of OP0. */
11878 if (sign_bit_comparison_p
&& HWI_COMPUTABLE_MODE_P (mode
))
11879 op0
= force_to_mode (op0
, mode
,
11881 << (GET_MODE_PRECISION (mode
) - 1),
11884 /* Now try cases based on the opcode of OP0. If none of the cases
11885 does a "continue", we exit this loop immediately after the
11888 switch (GET_CODE (op0
))
11891 /* If we are extracting a single bit from a variable position in
11892 a constant that has only a single bit set and are comparing it
11893 with zero, we can convert this into an equality comparison
11894 between the position and the location of the single bit. */
11895 /* Except we can't if SHIFT_COUNT_TRUNCATED is set, since we might
11896 have already reduced the shift count modulo the word size. */
11897 if (!SHIFT_COUNT_TRUNCATED
11898 && CONST_INT_P (XEXP (op0
, 0))
11899 && XEXP (op0
, 1) == const1_rtx
11900 && equality_comparison_p
&& const_op
== 0
11901 && (i
= exact_log2 (UINTVAL (XEXP (op0
, 0)))) >= 0)
11903 if (BITS_BIG_ENDIAN
)
11904 i
= BITS_PER_WORD
- 1 - i
;
11906 op0
= XEXP (op0
, 2);
11910 /* Result is nonzero iff shift count is equal to I. */
11911 code
= reverse_condition (code
);
11918 tem
= expand_compound_operation (op0
);
11927 /* If testing for equality, we can take the NOT of the constant. */
11928 if (equality_comparison_p
11929 && (tem
= simplify_unary_operation (NOT
, mode
, op1
, mode
)) != 0)
11931 op0
= XEXP (op0
, 0);
11936 /* If just looking at the sign bit, reverse the sense of the
11938 if (sign_bit_comparison_p
)
11940 op0
= XEXP (op0
, 0);
11941 code
= (code
== GE
? LT
: GE
);
11947 /* If testing for equality, we can take the NEG of the constant. */
11948 if (equality_comparison_p
11949 && (tem
= simplify_unary_operation (NEG
, mode
, op1
, mode
)) != 0)
11951 op0
= XEXP (op0
, 0);
11956 /* The remaining cases only apply to comparisons with zero. */
11960 /* When X is ABS or is known positive,
11961 (neg X) is < 0 if and only if X != 0. */
11963 if (sign_bit_comparison_p
11964 && (GET_CODE (XEXP (op0
, 0)) == ABS
11965 || (mode_width
<= HOST_BITS_PER_WIDE_INT
11966 && (nonzero_bits (XEXP (op0
, 0), mode
)
11967 & (HOST_WIDE_INT_1U
<< (mode_width
- 1)))
11970 op0
= XEXP (op0
, 0);
11971 code
= (code
== LT
? NE
: EQ
);
11975 /* If we have NEG of something whose two high-order bits are the
11976 same, we know that "(-a) < 0" is equivalent to "a > 0". */
11977 if (num_sign_bit_copies (op0
, mode
) >= 2)
11979 op0
= XEXP (op0
, 0);
11980 code
= swap_condition (code
);
11986 /* If we are testing equality and our count is a constant, we
11987 can perform the inverse operation on our RHS. */
11988 if (equality_comparison_p
&& CONST_INT_P (XEXP (op0
, 1))
11989 && (tem
= simplify_binary_operation (ROTATERT
, mode
,
11990 op1
, XEXP (op0
, 1))) != 0)
11992 op0
= XEXP (op0
, 0);
11997 /* If we are doing a < 0 or >= 0 comparison, it means we are testing
11998 a particular bit. Convert it to an AND of a constant of that
11999 bit. This will be converted into a ZERO_EXTRACT. */
12000 if (const_op
== 0 && sign_bit_comparison_p
12001 && CONST_INT_P (XEXP (op0
, 1))
12002 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
12004 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
12007 - INTVAL (XEXP (op0
, 1)))));
12008 code
= (code
== LT
? NE
: EQ
);
12012 /* Fall through. */
12015 /* ABS is ignorable inside an equality comparison with zero. */
12016 if (const_op
== 0 && equality_comparison_p
)
12018 op0
= XEXP (op0
, 0);
12024 /* Can simplify (compare (zero/sign_extend FOO) CONST) to
12025 (compare FOO CONST) if CONST fits in FOO's mode and we
12026 are either testing inequality or have an unsigned
12027 comparison with ZERO_EXTEND or a signed comparison with
12028 SIGN_EXTEND. But don't do it if we don't have a compare
12029 insn of the given mode, since we'd have to revert it
12030 later on, and then we wouldn't know whether to sign- or
12032 mode
= GET_MODE (XEXP (op0
, 0));
12033 if (GET_MODE_CLASS (mode
) == MODE_INT
12034 && ! unsigned_comparison_p
12035 && HWI_COMPUTABLE_MODE_P (mode
)
12036 && trunc_int_for_mode (const_op
, mode
) == const_op
12037 && have_insn_for (COMPARE
, mode
))
12039 op0
= XEXP (op0
, 0);
12045 /* Check for the case where we are comparing A - C1 with C2, that is
12047 (subreg:MODE (plus (A) (-C1))) op (C2)
12049 with C1 a constant, and try to lift the SUBREG, i.e. to do the
12050 comparison in the wider mode. One of the following two conditions
12051 must be true in order for this to be valid:
12053 1. The mode extension results in the same bit pattern being added
12054 on both sides and the comparison is equality or unsigned. As
12055 C2 has been truncated to fit in MODE, the pattern can only be
12058 2. The mode extension results in the sign bit being copied on
12061 The difficulty here is that we have predicates for A but not for
12062 (A - C1) so we need to check that C1 is within proper bounds so
12063 as to perturbate A as little as possible. */
12065 if (mode_width
<= HOST_BITS_PER_WIDE_INT
12066 && subreg_lowpart_p (op0
)
12067 && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
))) > mode_width
12068 && GET_CODE (SUBREG_REG (op0
)) == PLUS
12069 && CONST_INT_P (XEXP (SUBREG_REG (op0
), 1)))
12071 machine_mode inner_mode
= GET_MODE (SUBREG_REG (op0
));
12072 rtx a
= XEXP (SUBREG_REG (op0
), 0);
12073 HOST_WIDE_INT c1
= -INTVAL (XEXP (SUBREG_REG (op0
), 1));
12076 && (unsigned HOST_WIDE_INT
) c1
12077 < HOST_WIDE_INT_1U
<< (mode_width
- 1)
12078 && (equality_comparison_p
|| unsigned_comparison_p
)
12079 /* (A - C1) zero-extends if it is positive and sign-extends
12080 if it is negative, C2 both zero- and sign-extends. */
12081 && ((0 == (nonzero_bits (a
, inner_mode
)
12082 & ~GET_MODE_MASK (mode
))
12084 /* (A - C1) sign-extends if it is positive and 1-extends
12085 if it is negative, C2 both sign- and 1-extends. */
12086 || (num_sign_bit_copies (a
, inner_mode
)
12087 > (unsigned int) (GET_MODE_PRECISION (inner_mode
)
12090 || ((unsigned HOST_WIDE_INT
) c1
12091 < HOST_WIDE_INT_1U
<< (mode_width
- 2)
12092 /* (A - C1) always sign-extends, like C2. */
12093 && num_sign_bit_copies (a
, inner_mode
)
12094 > (unsigned int) (GET_MODE_PRECISION (inner_mode
)
12095 - (mode_width
- 1))))
12097 op0
= SUBREG_REG (op0
);
12102 /* If the inner mode is narrower and we are extracting the low part,
12103 we can treat the SUBREG as if it were a ZERO_EXTEND. */
12104 if (subreg_lowpart_p (op0
)
12105 && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
))) < mode_width
)
12107 else if (subreg_lowpart_p (op0
)
12108 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
12109 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (op0
))) == MODE_INT
12110 && (code
== NE
|| code
== EQ
)
12111 && (GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
)))
12112 <= HOST_BITS_PER_WIDE_INT
)
12113 && !paradoxical_subreg_p (op0
)
12114 && (nonzero_bits (SUBREG_REG (op0
),
12115 GET_MODE (SUBREG_REG (op0
)))
12116 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12118 /* Remove outer subregs that don't do anything. */
12119 tem
= gen_lowpart (GET_MODE (SUBREG_REG (op0
)), op1
);
12121 if ((nonzero_bits (tem
, GET_MODE (SUBREG_REG (op0
)))
12122 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12124 op0
= SUBREG_REG (op0
);
12136 mode
= GET_MODE (XEXP (op0
, 0));
12137 if (GET_MODE_CLASS (mode
) == MODE_INT
12138 && (unsigned_comparison_p
|| equality_comparison_p
)
12139 && HWI_COMPUTABLE_MODE_P (mode
)
12140 && (unsigned HOST_WIDE_INT
) const_op
<= GET_MODE_MASK (mode
)
12142 && have_insn_for (COMPARE
, mode
))
12144 op0
= XEXP (op0
, 0);
12150 /* (eq (plus X A) B) -> (eq X (minus B A)). We can only do
12151 this for equality comparisons due to pathological cases involving
12153 if (equality_comparison_p
12154 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
12155 op1
, XEXP (op0
, 1))))
12157 op0
= XEXP (op0
, 0);
12162 /* (plus (abs X) (const_int -1)) is < 0 if and only if X == 0. */
12163 if (const_op
== 0 && XEXP (op0
, 1) == constm1_rtx
12164 && GET_CODE (XEXP (op0
, 0)) == ABS
&& sign_bit_comparison_p
)
12166 op0
= XEXP (XEXP (op0
, 0), 0);
12167 code
= (code
== LT
? EQ
: NE
);
12173 /* We used to optimize signed comparisons against zero, but that
12174 was incorrect. Unsigned comparisons against zero (GTU, LEU)
12175 arrive here as equality comparisons, or (GEU, LTU) are
12176 optimized away. No need to special-case them. */
12178 /* (eq (minus A B) C) -> (eq A (plus B C)) or
12179 (eq B (minus A C)), whichever simplifies. We can only do
12180 this for equality comparisons due to pathological cases involving
12182 if (equality_comparison_p
12183 && 0 != (tem
= simplify_binary_operation (PLUS
, mode
,
12184 XEXP (op0
, 1), op1
)))
12186 op0
= XEXP (op0
, 0);
12191 if (equality_comparison_p
12192 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
12193 XEXP (op0
, 0), op1
)))
12195 op0
= XEXP (op0
, 1);
12200 /* The sign bit of (minus (ashiftrt X C) X), where C is the number
12201 of bits in X minus 1, is one iff X > 0. */
12202 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == ASHIFTRT
12203 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
12204 && UINTVAL (XEXP (XEXP (op0
, 0), 1)) == mode_width
- 1
12205 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
12207 op0
= XEXP (op0
, 1);
12208 code
= (code
== GE
? LE
: GT
);
12214 /* (eq (xor A B) C) -> (eq A (xor B C)). This is a simplification
12215 if C is zero or B is a constant. */
12216 if (equality_comparison_p
12217 && 0 != (tem
= simplify_binary_operation (XOR
, mode
,
12218 XEXP (op0
, 1), op1
)))
12220 op0
= XEXP (op0
, 0);
12227 case UNEQ
: case LTGT
:
12228 case LT
: case LTU
: case UNLT
: case LE
: case LEU
: case UNLE
:
12229 case GT
: case GTU
: case UNGT
: case GE
: case GEU
: case UNGE
:
12230 case UNORDERED
: case ORDERED
:
12231 /* We can't do anything if OP0 is a condition code value, rather
12232 than an actual data value. */
12234 || CC0_P (XEXP (op0
, 0))
12235 || GET_MODE_CLASS (GET_MODE (XEXP (op0
, 0))) == MODE_CC
)
12238 /* Get the two operands being compared. */
12239 if (GET_CODE (XEXP (op0
, 0)) == COMPARE
)
12240 tem
= XEXP (XEXP (op0
, 0), 0), tem1
= XEXP (XEXP (op0
, 0), 1);
12242 tem
= XEXP (op0
, 0), tem1
= XEXP (op0
, 1);
12244 /* Check for the cases where we simply want the result of the
12245 earlier test or the opposite of that result. */
12246 if (code
== NE
|| code
== EQ
12247 || (val_signbit_known_set_p (GET_MODE (op0
), STORE_FLAG_VALUE
)
12248 && (code
== LT
|| code
== GE
)))
12250 enum rtx_code new_code
;
12251 if (code
== LT
|| code
== NE
)
12252 new_code
= GET_CODE (op0
);
12254 new_code
= reversed_comparison_code (op0
, NULL
);
12256 if (new_code
!= UNKNOWN
)
12267 /* The sign bit of (ior (plus X (const_int -1)) X) is nonzero
12269 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == PLUS
12270 && XEXP (XEXP (op0
, 0), 1) == constm1_rtx
12271 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
12273 op0
= XEXP (op0
, 1);
12274 code
= (code
== GE
? GT
: LE
);
12280 /* Convert (and (xshift 1 X) Y) to (and (lshiftrt Y X) 1). This
12281 will be converted to a ZERO_EXTRACT later. */
12282 if (const_op
== 0 && equality_comparison_p
12283 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
12284 && XEXP (XEXP (op0
, 0), 0) == const1_rtx
)
12286 op0
= gen_rtx_LSHIFTRT (mode
, XEXP (op0
, 1),
12287 XEXP (XEXP (op0
, 0), 1));
12288 op0
= simplify_and_const_int (NULL_RTX
, mode
, op0
, 1);
12292 /* If we are comparing (and (lshiftrt X C1) C2) for equality with
12293 zero and X is a comparison and C1 and C2 describe only bits set
12294 in STORE_FLAG_VALUE, we can compare with X. */
12295 if (const_op
== 0 && equality_comparison_p
12296 && mode_width
<= HOST_BITS_PER_WIDE_INT
12297 && CONST_INT_P (XEXP (op0
, 1))
12298 && GET_CODE (XEXP (op0
, 0)) == LSHIFTRT
12299 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
12300 && INTVAL (XEXP (XEXP (op0
, 0), 1)) >= 0
12301 && INTVAL (XEXP (XEXP (op0
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
12303 mask
= ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
12304 << INTVAL (XEXP (XEXP (op0
, 0), 1)));
12305 if ((~STORE_FLAG_VALUE
& mask
) == 0
12306 && (COMPARISON_P (XEXP (XEXP (op0
, 0), 0))
12307 || ((tem
= get_last_value (XEXP (XEXP (op0
, 0), 0))) != 0
12308 && COMPARISON_P (tem
))))
12310 op0
= XEXP (XEXP (op0
, 0), 0);
12315 /* If we are doing an equality comparison of an AND of a bit equal
12316 to the sign bit, replace this with a LT or GE comparison of
12317 the underlying value. */
12318 if (equality_comparison_p
12320 && CONST_INT_P (XEXP (op0
, 1))
12321 && mode_width
<= HOST_BITS_PER_WIDE_INT
12322 && ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
12323 == HOST_WIDE_INT_1U
<< (mode_width
- 1)))
12325 op0
= XEXP (op0
, 0);
12326 code
= (code
== EQ
? GE
: LT
);
12330 /* If this AND operation is really a ZERO_EXTEND from a narrower
12331 mode, the constant fits within that mode, and this is either an
12332 equality or unsigned comparison, try to do this comparison in
12337 (ne:DI (and:DI (reg:DI 4) (const_int 0xffffffff)) (const_int 0))
12338 -> (ne:DI (reg:SI 4) (const_int 0))
12340 unless TRULY_NOOP_TRUNCATION allows it or the register is
12341 known to hold a value of the required mode the
12342 transformation is invalid. */
12343 if ((equality_comparison_p
|| unsigned_comparison_p
)
12344 && CONST_INT_P (XEXP (op0
, 1))
12345 && (i
= exact_log2 ((UINTVAL (XEXP (op0
, 1))
12346 & GET_MODE_MASK (mode
))
12348 && const_op
>> i
== 0
12349 && (tmode
= mode_for_size (i
, MODE_INT
, 1)) != BLKmode
)
12351 op0
= gen_lowpart_or_truncate (tmode
, XEXP (op0
, 0));
12355 /* If this is (and:M1 (subreg:M1 X:M2 0) (const_int C1)) where C1
12356 fits in both M1 and M2 and the SUBREG is either paradoxical
12357 or represents the low part, permute the SUBREG and the AND
12359 if (GET_CODE (XEXP (op0
, 0)) == SUBREG
12360 && CONST_INT_P (XEXP (op0
, 1)))
12362 tmode
= GET_MODE (SUBREG_REG (XEXP (op0
, 0)));
12363 unsigned HOST_WIDE_INT c1
= INTVAL (XEXP (op0
, 1));
12364 /* Require an integral mode, to avoid creating something like
12366 if (SCALAR_INT_MODE_P (tmode
)
12367 /* It is unsafe to commute the AND into the SUBREG if the
12368 SUBREG is paradoxical and WORD_REGISTER_OPERATIONS is
12369 not defined. As originally written the upper bits
12370 have a defined value due to the AND operation.
12371 However, if we commute the AND inside the SUBREG then
12372 they no longer have defined values and the meaning of
12373 the code has been changed.
12374 Also C1 should not change value in the smaller mode,
12375 see PR67028 (a positive C1 can become negative in the
12376 smaller mode, so that the AND does no longer mask the
12378 && ((WORD_REGISTER_OPERATIONS
12379 && mode_width
> GET_MODE_PRECISION (tmode
)
12380 && mode_width
<= BITS_PER_WORD
12381 && trunc_int_for_mode (c1
, tmode
) == (HOST_WIDE_INT
) c1
)
12382 || (mode_width
<= GET_MODE_PRECISION (tmode
)
12383 && subreg_lowpart_p (XEXP (op0
, 0))))
12384 && mode_width
<= HOST_BITS_PER_WIDE_INT
12385 && HWI_COMPUTABLE_MODE_P (tmode
)
12386 && (c1
& ~mask
) == 0
12387 && (c1
& ~GET_MODE_MASK (tmode
)) == 0
12389 && c1
!= GET_MODE_MASK (tmode
))
12391 op0
= simplify_gen_binary (AND
, tmode
,
12392 SUBREG_REG (XEXP (op0
, 0)),
12393 gen_int_mode (c1
, tmode
));
12394 op0
= gen_lowpart (mode
, op0
);
12399 /* Convert (ne (and (not X) 1) 0) to (eq (and X 1) 0). */
12400 if (const_op
== 0 && equality_comparison_p
12401 && XEXP (op0
, 1) == const1_rtx
12402 && GET_CODE (XEXP (op0
, 0)) == NOT
)
12404 op0
= simplify_and_const_int (NULL_RTX
, mode
,
12405 XEXP (XEXP (op0
, 0), 0), 1);
12406 code
= (code
== NE
? EQ
: NE
);
12410 /* Convert (ne (and (lshiftrt (not X)) 1) 0) to
12411 (eq (and (lshiftrt X) 1) 0).
12412 Also handle the case where (not X) is expressed using xor. */
12413 if (const_op
== 0 && equality_comparison_p
12414 && XEXP (op0
, 1) == const1_rtx
12415 && GET_CODE (XEXP (op0
, 0)) == LSHIFTRT
)
12417 rtx shift_op
= XEXP (XEXP (op0
, 0), 0);
12418 rtx shift_count
= XEXP (XEXP (op0
, 0), 1);
12420 if (GET_CODE (shift_op
) == NOT
12421 || (GET_CODE (shift_op
) == XOR
12422 && CONST_INT_P (XEXP (shift_op
, 1))
12423 && CONST_INT_P (shift_count
)
12424 && HWI_COMPUTABLE_MODE_P (mode
)
12425 && (UINTVAL (XEXP (shift_op
, 1))
12426 == HOST_WIDE_INT_1U
12427 << INTVAL (shift_count
))))
12430 = gen_rtx_LSHIFTRT (mode
, XEXP (shift_op
, 0), shift_count
);
12431 op0
= simplify_and_const_int (NULL_RTX
, mode
, op0
, 1);
12432 code
= (code
== NE
? EQ
: NE
);
12439 /* If we have (compare (ashift FOO N) (const_int C)) and
12440 the high order N bits of FOO (N+1 if an inequality comparison)
12441 are known to be zero, we can do this by comparing FOO with C
12442 shifted right N bits so long as the low-order N bits of C are
12444 if (CONST_INT_P (XEXP (op0
, 1))
12445 && INTVAL (XEXP (op0
, 1)) >= 0
12446 && ((INTVAL (XEXP (op0
, 1)) + ! equality_comparison_p
)
12447 < HOST_BITS_PER_WIDE_INT
)
12448 && (((unsigned HOST_WIDE_INT
) const_op
12449 & ((HOST_WIDE_INT_1U
<< INTVAL (XEXP (op0
, 1)))
12451 && mode_width
<= HOST_BITS_PER_WIDE_INT
12452 && (nonzero_bits (XEXP (op0
, 0), mode
)
12453 & ~(mask
>> (INTVAL (XEXP (op0
, 1))
12454 + ! equality_comparison_p
))) == 0)
12456 /* We must perform a logical shift, not an arithmetic one,
12457 as we want the top N bits of C to be zero. */
12458 unsigned HOST_WIDE_INT temp
= const_op
& GET_MODE_MASK (mode
);
12460 temp
>>= INTVAL (XEXP (op0
, 1));
12461 op1
= gen_int_mode (temp
, mode
);
12462 op0
= XEXP (op0
, 0);
12466 /* If we are doing a sign bit comparison, it means we are testing
12467 a particular bit. Convert it to the appropriate AND. */
12468 if (sign_bit_comparison_p
&& CONST_INT_P (XEXP (op0
, 1))
12469 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
12471 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
12474 - INTVAL (XEXP (op0
, 1)))));
12475 code
= (code
== LT
? NE
: EQ
);
12479 /* If this an equality comparison with zero and we are shifting
12480 the low bit to the sign bit, we can convert this to an AND of the
12482 if (const_op
== 0 && equality_comparison_p
12483 && CONST_INT_P (XEXP (op0
, 1))
12484 && UINTVAL (XEXP (op0
, 1)) == mode_width
- 1)
12486 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0), 1);
12492 /* If this is an equality comparison with zero, we can do this
12493 as a logical shift, which might be much simpler. */
12494 if (equality_comparison_p
&& const_op
== 0
12495 && CONST_INT_P (XEXP (op0
, 1)))
12497 op0
= simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
,
12499 INTVAL (XEXP (op0
, 1)));
12503 /* If OP0 is a sign extension and CODE is not an unsigned comparison,
12504 do the comparison in a narrower mode. */
12505 if (! unsigned_comparison_p
12506 && CONST_INT_P (XEXP (op0
, 1))
12507 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
12508 && XEXP (op0
, 1) == XEXP (XEXP (op0
, 0), 1)
12509 && (tmode
= mode_for_size (mode_width
- INTVAL (XEXP (op0
, 1)),
12510 MODE_INT
, 1)) != BLKmode
12511 && (((unsigned HOST_WIDE_INT
) const_op
12512 + (GET_MODE_MASK (tmode
) >> 1) + 1)
12513 <= GET_MODE_MASK (tmode
)))
12515 op0
= gen_lowpart (tmode
, XEXP (XEXP (op0
, 0), 0));
12519 /* Likewise if OP0 is a PLUS of a sign extension with a
12520 constant, which is usually represented with the PLUS
12521 between the shifts. */
12522 if (! unsigned_comparison_p
12523 && CONST_INT_P (XEXP (op0
, 1))
12524 && GET_CODE (XEXP (op0
, 0)) == PLUS
12525 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
12526 && GET_CODE (XEXP (XEXP (op0
, 0), 0)) == ASHIFT
12527 && XEXP (op0
, 1) == XEXP (XEXP (XEXP (op0
, 0), 0), 1)
12528 && (tmode
= mode_for_size (mode_width
- INTVAL (XEXP (op0
, 1)),
12529 MODE_INT
, 1)) != BLKmode
12530 && (((unsigned HOST_WIDE_INT
) const_op
12531 + (GET_MODE_MASK (tmode
) >> 1) + 1)
12532 <= GET_MODE_MASK (tmode
)))
12534 rtx inner
= XEXP (XEXP (XEXP (op0
, 0), 0), 0);
12535 rtx add_const
= XEXP (XEXP (op0
, 0), 1);
12536 rtx new_const
= simplify_gen_binary (ASHIFTRT
, GET_MODE (op0
),
12537 add_const
, XEXP (op0
, 1));
12539 op0
= simplify_gen_binary (PLUS
, tmode
,
12540 gen_lowpart (tmode
, inner
),
12547 /* If we have (compare (xshiftrt FOO N) (const_int C)) and
12548 the low order N bits of FOO are known to be zero, we can do this
12549 by comparing FOO with C shifted left N bits so long as no
12550 overflow occurs. Even if the low order N bits of FOO aren't known
12551 to be zero, if the comparison is >= or < we can use the same
12552 optimization and for > or <= by setting all the low
12553 order N bits in the comparison constant. */
12554 if (CONST_INT_P (XEXP (op0
, 1))
12555 && INTVAL (XEXP (op0
, 1)) > 0
12556 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
12557 && mode_width
<= HOST_BITS_PER_WIDE_INT
12558 && (((unsigned HOST_WIDE_INT
) const_op
12559 + (GET_CODE (op0
) != LSHIFTRT
12560 ? ((GET_MODE_MASK (mode
) >> INTVAL (XEXP (op0
, 1)) >> 1)
12563 <= GET_MODE_MASK (mode
) >> INTVAL (XEXP (op0
, 1))))
12565 unsigned HOST_WIDE_INT low_bits
12566 = (nonzero_bits (XEXP (op0
, 0), mode
)
12567 & ((HOST_WIDE_INT_1U
12568 << INTVAL (XEXP (op0
, 1))) - 1));
12569 if (low_bits
== 0 || !equality_comparison_p
)
12571 /* If the shift was logical, then we must make the condition
12573 if (GET_CODE (op0
) == LSHIFTRT
)
12574 code
= unsigned_condition (code
);
12576 const_op
= (unsigned HOST_WIDE_INT
) const_op
12577 << INTVAL (XEXP (op0
, 1));
12579 && (code
== GT
|| code
== GTU
12580 || code
== LE
|| code
== LEU
))
12582 |= ((HOST_WIDE_INT_1
<< INTVAL (XEXP (op0
, 1))) - 1);
12583 op1
= GEN_INT (const_op
);
12584 op0
= XEXP (op0
, 0);
12589 /* If we are using this shift to extract just the sign bit, we
12590 can replace this with an LT or GE comparison. */
12592 && (equality_comparison_p
|| sign_bit_comparison_p
)
12593 && CONST_INT_P (XEXP (op0
, 1))
12594 && UINTVAL (XEXP (op0
, 1)) == mode_width
- 1)
12596 op0
= XEXP (op0
, 0);
12597 code
= (code
== NE
|| code
== GT
? LT
: GE
);
12609 /* Now make any compound operations involved in this comparison. Then,
12610 check for an outmost SUBREG on OP0 that is not doing anything or is
12611 paradoxical. The latter transformation must only be performed when
12612 it is known that the "extra" bits will be the same in op0 and op1 or
12613 that they don't matter. There are three cases to consider:
12615 1. SUBREG_REG (op0) is a register. In this case the bits are don't
12616 care bits and we can assume they have any convenient value. So
12617 making the transformation is safe.
12619 2. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is UNKNOWN.
12620 In this case the upper bits of op0 are undefined. We should not make
12621 the simplification in that case as we do not know the contents of
12624 3. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is not UNKNOWN.
12625 In that case we know those bits are zeros or ones. We must also be
12626 sure that they are the same as the upper bits of op1.
12628 We can never remove a SUBREG for a non-equality comparison because
12629 the sign bit is in a different place in the underlying object. */
12631 rtx_code op0_mco_code
= SET
;
12632 if (op1
== const0_rtx
)
12633 op0_mco_code
= code
== NE
|| code
== EQ
? EQ
: COMPARE
;
12635 op0
= make_compound_operation (op0
, op0_mco_code
);
12636 op1
= make_compound_operation (op1
, SET
);
12638 if (GET_CODE (op0
) == SUBREG
&& subreg_lowpart_p (op0
)
12639 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
12640 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (op0
))) == MODE_INT
12641 && (code
== NE
|| code
== EQ
))
12643 if (paradoxical_subreg_p (op0
))
12645 /* For paradoxical subregs, allow case 1 as above. Case 3 isn't
12647 if (REG_P (SUBREG_REG (op0
)))
12649 op0
= SUBREG_REG (op0
);
12650 op1
= gen_lowpart (GET_MODE (op0
), op1
);
12653 else if ((GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
)))
12654 <= HOST_BITS_PER_WIDE_INT
)
12655 && (nonzero_bits (SUBREG_REG (op0
),
12656 GET_MODE (SUBREG_REG (op0
)))
12657 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12659 tem
= gen_lowpart (GET_MODE (SUBREG_REG (op0
)), op1
);
12661 if ((nonzero_bits (tem
, GET_MODE (SUBREG_REG (op0
)))
12662 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12663 op0
= SUBREG_REG (op0
), op1
= tem
;
12667 /* We now do the opposite procedure: Some machines don't have compare
12668 insns in all modes. If OP0's mode is an integer mode smaller than a
12669 word and we can't do a compare in that mode, see if there is a larger
12670 mode for which we can do the compare. There are a number of cases in
12671 which we can use the wider mode. */
12673 mode
= GET_MODE (op0
);
12674 if (mode
!= VOIDmode
&& GET_MODE_CLASS (mode
) == MODE_INT
12675 && GET_MODE_SIZE (mode
) < UNITS_PER_WORD
12676 && ! have_insn_for (COMPARE
, mode
))
12677 for (tmode
= GET_MODE_WIDER_MODE (mode
);
12678 (tmode
!= VOIDmode
&& HWI_COMPUTABLE_MODE_P (tmode
));
12679 tmode
= GET_MODE_WIDER_MODE (tmode
))
12680 if (have_insn_for (COMPARE
, tmode
))
12684 /* If this is a test for negative, we can make an explicit
12685 test of the sign bit. Test this first so we can use
12686 a paradoxical subreg to extend OP0. */
12688 if (op1
== const0_rtx
&& (code
== LT
|| code
== GE
)
12689 && HWI_COMPUTABLE_MODE_P (mode
))
12691 unsigned HOST_WIDE_INT sign
12692 = HOST_WIDE_INT_1U
<< (GET_MODE_BITSIZE (mode
) - 1);
12693 op0
= simplify_gen_binary (AND
, tmode
,
12694 gen_lowpart (tmode
, op0
),
12695 gen_int_mode (sign
, tmode
));
12696 code
= (code
== LT
) ? NE
: EQ
;
12700 /* If the only nonzero bits in OP0 and OP1 are those in the
12701 narrower mode and this is an equality or unsigned comparison,
12702 we can use the wider mode. Similarly for sign-extended
12703 values, in which case it is true for all comparisons. */
12704 zero_extended
= ((code
== EQ
|| code
== NE
12705 || code
== GEU
|| code
== GTU
12706 || code
== LEU
|| code
== LTU
)
12707 && (nonzero_bits (op0
, tmode
)
12708 & ~GET_MODE_MASK (mode
)) == 0
12709 && ((CONST_INT_P (op1
)
12710 || (nonzero_bits (op1
, tmode
)
12711 & ~GET_MODE_MASK (mode
)) == 0)));
12714 || ((num_sign_bit_copies (op0
, tmode
)
12715 > (unsigned int) (GET_MODE_PRECISION (tmode
)
12716 - GET_MODE_PRECISION (mode
)))
12717 && (num_sign_bit_copies (op1
, tmode
)
12718 > (unsigned int) (GET_MODE_PRECISION (tmode
)
12719 - GET_MODE_PRECISION (mode
)))))
12721 /* If OP0 is an AND and we don't have an AND in MODE either,
12722 make a new AND in the proper mode. */
12723 if (GET_CODE (op0
) == AND
12724 && !have_insn_for (AND
, mode
))
12725 op0
= simplify_gen_binary (AND
, tmode
,
12726 gen_lowpart (tmode
,
12728 gen_lowpart (tmode
,
12734 op0
= simplify_gen_unary (ZERO_EXTEND
, tmode
, op0
, mode
);
12735 op1
= simplify_gen_unary (ZERO_EXTEND
, tmode
, op1
, mode
);
12739 op0
= simplify_gen_unary (SIGN_EXTEND
, tmode
, op0
, mode
);
12740 op1
= simplify_gen_unary (SIGN_EXTEND
, tmode
, op1
, mode
);
12747 /* We may have changed the comparison operands. Re-canonicalize. */
12748 if (swap_commutative_operands_p (op0
, op1
))
12750 std::swap (op0
, op1
);
12751 code
= swap_condition (code
);
12754 /* If this machine only supports a subset of valid comparisons, see if we
12755 can convert an unsupported one into a supported one. */
12756 target_canonicalize_comparison (&code
, &op0
, &op1
, 0);
12764 /* Utility function for record_value_for_reg. Count number of
12769 enum rtx_code code
= GET_CODE (x
);
12773 if (GET_RTX_CLASS (code
) == RTX_BIN_ARITH
12774 || GET_RTX_CLASS (code
) == RTX_COMM_ARITH
)
12776 rtx x0
= XEXP (x
, 0);
12777 rtx x1
= XEXP (x
, 1);
12780 return 1 + 2 * count_rtxs (x0
);
12782 if ((GET_RTX_CLASS (GET_CODE (x1
)) == RTX_BIN_ARITH
12783 || GET_RTX_CLASS (GET_CODE (x1
)) == RTX_COMM_ARITH
)
12784 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
12785 return 2 + 2 * count_rtxs (x0
)
12786 + count_rtxs (x
== XEXP (x1
, 0)
12787 ? XEXP (x1
, 1) : XEXP (x1
, 0));
12789 if ((GET_RTX_CLASS (GET_CODE (x0
)) == RTX_BIN_ARITH
12790 || GET_RTX_CLASS (GET_CODE (x0
)) == RTX_COMM_ARITH
)
12791 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
12792 return 2 + 2 * count_rtxs (x1
)
12793 + count_rtxs (x
== XEXP (x0
, 0)
12794 ? XEXP (x0
, 1) : XEXP (x0
, 0));
12797 fmt
= GET_RTX_FORMAT (code
);
12798 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
12800 ret
+= count_rtxs (XEXP (x
, i
));
12801 else if (fmt
[i
] == 'E')
12802 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
12803 ret
+= count_rtxs (XVECEXP (x
, i
, j
));
12808 /* Utility function for following routine. Called when X is part of a value
12809 being stored into last_set_value. Sets last_set_table_tick
12810 for each register mentioned. Similar to mention_regs in cse.c */
12813 update_table_tick (rtx x
)
12815 enum rtx_code code
= GET_CODE (x
);
12816 const char *fmt
= GET_RTX_FORMAT (code
);
12821 unsigned int regno
= REGNO (x
);
12822 unsigned int endregno
= END_REGNO (x
);
12825 for (r
= regno
; r
< endregno
; r
++)
12827 reg_stat_type
*rsp
= ®_stat
[r
];
12828 rsp
->last_set_table_tick
= label_tick
;
12834 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
12837 /* Check for identical subexpressions. If x contains
12838 identical subexpression we only have to traverse one of
12840 if (i
== 0 && ARITHMETIC_P (x
))
12842 /* Note that at this point x1 has already been
12844 rtx x0
= XEXP (x
, 0);
12845 rtx x1
= XEXP (x
, 1);
12847 /* If x0 and x1 are identical then there is no need to
12852 /* If x0 is identical to a subexpression of x1 then while
12853 processing x1, x0 has already been processed. Thus we
12854 are done with x. */
12855 if (ARITHMETIC_P (x1
)
12856 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
12859 /* If x1 is identical to a subexpression of x0 then we
12860 still have to process the rest of x0. */
12861 if (ARITHMETIC_P (x0
)
12862 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
12864 update_table_tick (XEXP (x0
, x1
== XEXP (x0
, 0) ? 1 : 0));
12869 update_table_tick (XEXP (x
, i
));
12871 else if (fmt
[i
] == 'E')
12872 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
12873 update_table_tick (XVECEXP (x
, i
, j
));
12876 /* Record that REG is set to VALUE in insn INSN. If VALUE is zero, we
12877 are saying that the register is clobbered and we no longer know its
12878 value. If INSN is zero, don't update reg_stat[].last_set; this is
12879 only permitted with VALUE also zero and is used to invalidate the
12883 record_value_for_reg (rtx reg
, rtx_insn
*insn
, rtx value
)
12885 unsigned int regno
= REGNO (reg
);
12886 unsigned int endregno
= END_REGNO (reg
);
12888 reg_stat_type
*rsp
;
12890 /* If VALUE contains REG and we have a previous value for REG, substitute
12891 the previous value. */
12892 if (value
&& insn
&& reg_overlap_mentioned_p (reg
, value
))
12896 /* Set things up so get_last_value is allowed to see anything set up to
12898 subst_low_luid
= DF_INSN_LUID (insn
);
12899 tem
= get_last_value (reg
);
12901 /* If TEM is simply a binary operation with two CLOBBERs as operands,
12902 it isn't going to be useful and will take a lot of time to process,
12903 so just use the CLOBBER. */
12907 if (ARITHMETIC_P (tem
)
12908 && GET_CODE (XEXP (tem
, 0)) == CLOBBER
12909 && GET_CODE (XEXP (tem
, 1)) == CLOBBER
)
12910 tem
= XEXP (tem
, 0);
12911 else if (count_occurrences (value
, reg
, 1) >= 2)
12913 /* If there are two or more occurrences of REG in VALUE,
12914 prevent the value from growing too much. */
12915 if (count_rtxs (tem
) > MAX_LAST_VALUE_RTL
)
12916 tem
= gen_rtx_CLOBBER (GET_MODE (tem
), const0_rtx
);
12919 value
= replace_rtx (copy_rtx (value
), reg
, tem
);
12923 /* For each register modified, show we don't know its value, that
12924 we don't know about its bitwise content, that its value has been
12925 updated, and that we don't know the location of the death of the
12927 for (i
= regno
; i
< endregno
; i
++)
12929 rsp
= ®_stat
[i
];
12932 rsp
->last_set
= insn
;
12934 rsp
->last_set_value
= 0;
12935 rsp
->last_set_mode
= VOIDmode
;
12936 rsp
->last_set_nonzero_bits
= 0;
12937 rsp
->last_set_sign_bit_copies
= 0;
12938 rsp
->last_death
= 0;
12939 rsp
->truncated_to_mode
= VOIDmode
;
12942 /* Mark registers that are being referenced in this value. */
12944 update_table_tick (value
);
12946 /* Now update the status of each register being set.
12947 If someone is using this register in this block, set this register
12948 to invalid since we will get confused between the two lives in this
12949 basic block. This makes using this register always invalid. In cse, we
12950 scan the table to invalidate all entries using this register, but this
12951 is too much work for us. */
12953 for (i
= regno
; i
< endregno
; i
++)
12955 rsp
= ®_stat
[i
];
12956 rsp
->last_set_label
= label_tick
;
12958 || (value
&& rsp
->last_set_table_tick
>= label_tick_ebb_start
))
12959 rsp
->last_set_invalid
= 1;
12961 rsp
->last_set_invalid
= 0;
12964 /* The value being assigned might refer to X (like in "x++;"). In that
12965 case, we must replace it with (clobber (const_int 0)) to prevent
12967 rsp
= ®_stat
[regno
];
12968 if (value
&& !get_last_value_validate (&value
, insn
, label_tick
, 0))
12970 value
= copy_rtx (value
);
12971 if (!get_last_value_validate (&value
, insn
, label_tick
, 1))
12975 /* For the main register being modified, update the value, the mode, the
12976 nonzero bits, and the number of sign bit copies. */
12978 rsp
->last_set_value
= value
;
12982 machine_mode mode
= GET_MODE (reg
);
12983 subst_low_luid
= DF_INSN_LUID (insn
);
12984 rsp
->last_set_mode
= mode
;
12985 if (GET_MODE_CLASS (mode
) == MODE_INT
12986 && HWI_COMPUTABLE_MODE_P (mode
))
12987 mode
= nonzero_bits_mode
;
12988 rsp
->last_set_nonzero_bits
= nonzero_bits (value
, mode
);
12989 rsp
->last_set_sign_bit_copies
12990 = num_sign_bit_copies (value
, GET_MODE (reg
));
12994 /* Called via note_stores from record_dead_and_set_regs to handle one
12995 SET or CLOBBER in an insn. DATA is the instruction in which the
12996 set is occurring. */
12999 record_dead_and_set_regs_1 (rtx dest
, const_rtx setter
, void *data
)
13001 rtx_insn
*record_dead_insn
= (rtx_insn
*) data
;
13003 if (GET_CODE (dest
) == SUBREG
)
13004 dest
= SUBREG_REG (dest
);
13006 if (!record_dead_insn
)
13009 record_value_for_reg (dest
, NULL
, NULL_RTX
);
13015 /* If we are setting the whole register, we know its value. Otherwise
13016 show that we don't know the value. We can handle SUBREG in
13018 if (GET_CODE (setter
) == SET
&& dest
== SET_DEST (setter
))
13019 record_value_for_reg (dest
, record_dead_insn
, SET_SRC (setter
));
13020 else if (GET_CODE (setter
) == SET
13021 && GET_CODE (SET_DEST (setter
)) == SUBREG
13022 && SUBREG_REG (SET_DEST (setter
)) == dest
13023 && GET_MODE_PRECISION (GET_MODE (dest
)) <= BITS_PER_WORD
13024 && subreg_lowpart_p (SET_DEST (setter
)))
13025 record_value_for_reg (dest
, record_dead_insn
,
13026 gen_lowpart (GET_MODE (dest
),
13027 SET_SRC (setter
)));
13029 record_value_for_reg (dest
, record_dead_insn
, NULL_RTX
);
13031 else if (MEM_P (dest
)
13032 /* Ignore pushes, they clobber nothing. */
13033 && ! push_operand (dest
, GET_MODE (dest
)))
13034 mem_last_set
= DF_INSN_LUID (record_dead_insn
);
13037 /* Update the records of when each REG was most recently set or killed
13038 for the things done by INSN. This is the last thing done in processing
13039 INSN in the combiner loop.
13041 We update reg_stat[], in particular fields last_set, last_set_value,
13042 last_set_mode, last_set_nonzero_bits, last_set_sign_bit_copies,
13043 last_death, and also the similar information mem_last_set (which insn
13044 most recently modified memory) and last_call_luid (which insn was the
13045 most recent subroutine call). */
13048 record_dead_and_set_regs (rtx_insn
*insn
)
13053 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
13055 if (REG_NOTE_KIND (link
) == REG_DEAD
13056 && REG_P (XEXP (link
, 0)))
13058 unsigned int regno
= REGNO (XEXP (link
, 0));
13059 unsigned int endregno
= END_REGNO (XEXP (link
, 0));
13061 for (i
= regno
; i
< endregno
; i
++)
13063 reg_stat_type
*rsp
;
13065 rsp
= ®_stat
[i
];
13066 rsp
->last_death
= insn
;
13069 else if (REG_NOTE_KIND (link
) == REG_INC
)
13070 record_value_for_reg (XEXP (link
, 0), insn
, NULL_RTX
);
13075 hard_reg_set_iterator hrsi
;
13076 EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call
, 0, i
, hrsi
)
13078 reg_stat_type
*rsp
;
13080 rsp
= ®_stat
[i
];
13081 rsp
->last_set_invalid
= 1;
13082 rsp
->last_set
= insn
;
13083 rsp
->last_set_value
= 0;
13084 rsp
->last_set_mode
= VOIDmode
;
13085 rsp
->last_set_nonzero_bits
= 0;
13086 rsp
->last_set_sign_bit_copies
= 0;
13087 rsp
->last_death
= 0;
13088 rsp
->truncated_to_mode
= VOIDmode
;
13091 last_call_luid
= mem_last_set
= DF_INSN_LUID (insn
);
13093 /* We can't combine into a call pattern. Remember, though, that
13094 the return value register is set at this LUID. We could
13095 still replace a register with the return value from the
13096 wrong subroutine call! */
13097 note_stores (PATTERN (insn
), record_dead_and_set_regs_1
, NULL_RTX
);
13100 note_stores (PATTERN (insn
), record_dead_and_set_regs_1
, insn
);
13103 /* If a SUBREG has the promoted bit set, it is in fact a property of the
13104 register present in the SUBREG, so for each such SUBREG go back and
13105 adjust nonzero and sign bit information of the registers that are
13106 known to have some zero/sign bits set.
13108 This is needed because when combine blows the SUBREGs away, the
13109 information on zero/sign bits is lost and further combines can be
13110 missed because of that. */
13113 record_promoted_value (rtx_insn
*insn
, rtx subreg
)
13115 struct insn_link
*links
;
13117 unsigned int regno
= REGNO (SUBREG_REG (subreg
));
13118 machine_mode mode
= GET_MODE (subreg
);
13120 if (GET_MODE_PRECISION (mode
) > HOST_BITS_PER_WIDE_INT
)
13123 for (links
= LOG_LINKS (insn
); links
;)
13125 reg_stat_type
*rsp
;
13127 insn
= links
->insn
;
13128 set
= single_set (insn
);
13130 if (! set
|| !REG_P (SET_DEST (set
))
13131 || REGNO (SET_DEST (set
)) != regno
13132 || GET_MODE (SET_DEST (set
)) != GET_MODE (SUBREG_REG (subreg
)))
13134 links
= links
->next
;
13138 rsp
= ®_stat
[regno
];
13139 if (rsp
->last_set
== insn
)
13141 if (SUBREG_PROMOTED_UNSIGNED_P (subreg
))
13142 rsp
->last_set_nonzero_bits
&= GET_MODE_MASK (mode
);
13145 if (REG_P (SET_SRC (set
)))
13147 regno
= REGNO (SET_SRC (set
));
13148 links
= LOG_LINKS (insn
);
13155 /* Check if X, a register, is known to contain a value already
13156 truncated to MODE. In this case we can use a subreg to refer to
13157 the truncated value even though in the generic case we would need
13158 an explicit truncation. */
13161 reg_truncated_to_mode (machine_mode mode
, const_rtx x
)
13163 reg_stat_type
*rsp
= ®_stat
[REGNO (x
)];
13164 machine_mode truncated
= rsp
->truncated_to_mode
;
13167 || rsp
->truncation_label
< label_tick_ebb_start
)
13169 if (GET_MODE_SIZE (truncated
) <= GET_MODE_SIZE (mode
))
13171 if (TRULY_NOOP_TRUNCATION_MODES_P (mode
, truncated
))
13176 /* If X is a hard reg or a subreg record the mode that the register is
13177 accessed in. For non-TRULY_NOOP_TRUNCATION targets we might be able
13178 to turn a truncate into a subreg using this information. Return true
13179 if traversing X is complete. */
13182 record_truncated_value (rtx x
)
13184 machine_mode truncated_mode
;
13185 reg_stat_type
*rsp
;
13187 if (GET_CODE (x
) == SUBREG
&& REG_P (SUBREG_REG (x
)))
13189 machine_mode original_mode
= GET_MODE (SUBREG_REG (x
));
13190 truncated_mode
= GET_MODE (x
);
13192 if (GET_MODE_SIZE (original_mode
) <= GET_MODE_SIZE (truncated_mode
))
13195 if (TRULY_NOOP_TRUNCATION_MODES_P (truncated_mode
, original_mode
))
13198 x
= SUBREG_REG (x
);
13200 /* ??? For hard-regs we now record everything. We might be able to
13201 optimize this using last_set_mode. */
13202 else if (REG_P (x
) && REGNO (x
) < FIRST_PSEUDO_REGISTER
)
13203 truncated_mode
= GET_MODE (x
);
13207 rsp
= ®_stat
[REGNO (x
)];
13208 if (rsp
->truncated_to_mode
== 0
13209 || rsp
->truncation_label
< label_tick_ebb_start
13210 || (GET_MODE_SIZE (truncated_mode
)
13211 < GET_MODE_SIZE (rsp
->truncated_to_mode
)))
13213 rsp
->truncated_to_mode
= truncated_mode
;
13214 rsp
->truncation_label
= label_tick
;
13220 /* Callback for note_uses. Find hardregs and subregs of pseudos and
13221 the modes they are used in. This can help truning TRUNCATEs into
13225 record_truncated_values (rtx
*loc
, void *data ATTRIBUTE_UNUSED
)
13227 subrtx_var_iterator::array_type array
;
13228 FOR_EACH_SUBRTX_VAR (iter
, array
, *loc
, NONCONST
)
13229 if (record_truncated_value (*iter
))
13230 iter
.skip_subrtxes ();
13233 /* Scan X for promoted SUBREGs. For each one found,
13234 note what it implies to the registers used in it. */
13237 check_promoted_subreg (rtx_insn
*insn
, rtx x
)
13239 if (GET_CODE (x
) == SUBREG
13240 && SUBREG_PROMOTED_VAR_P (x
)
13241 && REG_P (SUBREG_REG (x
)))
13242 record_promoted_value (insn
, x
);
13245 const char *format
= GET_RTX_FORMAT (GET_CODE (x
));
13248 for (i
= 0; i
< GET_RTX_LENGTH (GET_CODE (x
)); i
++)
13252 check_promoted_subreg (insn
, XEXP (x
, i
));
13256 if (XVEC (x
, i
) != 0)
13257 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13258 check_promoted_subreg (insn
, XVECEXP (x
, i
, j
));
13264 /* Verify that all the registers and memory references mentioned in *LOC are
13265 still valid. *LOC was part of a value set in INSN when label_tick was
13266 equal to TICK. Return 0 if some are not. If REPLACE is nonzero, replace
13267 the invalid references with (clobber (const_int 0)) and return 1. This
13268 replacement is useful because we often can get useful information about
13269 the form of a value (e.g., if it was produced by a shift that always
13270 produces -1 or 0) even though we don't know exactly what registers it
13271 was produced from. */
13274 get_last_value_validate (rtx
*loc
, rtx_insn
*insn
, int tick
, int replace
)
13277 const char *fmt
= GET_RTX_FORMAT (GET_CODE (x
));
13278 int len
= GET_RTX_LENGTH (GET_CODE (x
));
13283 unsigned int regno
= REGNO (x
);
13284 unsigned int endregno
= END_REGNO (x
);
13287 for (j
= regno
; j
< endregno
; j
++)
13289 reg_stat_type
*rsp
= ®_stat
[j
];
13290 if (rsp
->last_set_invalid
13291 /* If this is a pseudo-register that was only set once and not
13292 live at the beginning of the function, it is always valid. */
13293 || (! (regno
>= FIRST_PSEUDO_REGISTER
13294 && regno
< reg_n_sets_max
13295 && REG_N_SETS (regno
) == 1
13296 && (!REGNO_REG_SET_P
13297 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
13299 && rsp
->last_set_label
> tick
))
13302 *loc
= gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
13309 /* If this is a memory reference, make sure that there were no stores after
13310 it that might have clobbered the value. We don't have alias info, so we
13311 assume any store invalidates it. Moreover, we only have local UIDs, so
13312 we also assume that there were stores in the intervening basic blocks. */
13313 else if (MEM_P (x
) && !MEM_READONLY_P (x
)
13314 && (tick
!= label_tick
|| DF_INSN_LUID (insn
) <= mem_last_set
))
13317 *loc
= gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
13321 for (i
= 0; i
< len
; i
++)
13325 /* Check for identical subexpressions. If x contains
13326 identical subexpression we only have to traverse one of
13328 if (i
== 1 && ARITHMETIC_P (x
))
13330 /* Note that at this point x0 has already been checked
13331 and found valid. */
13332 rtx x0
= XEXP (x
, 0);
13333 rtx x1
= XEXP (x
, 1);
13335 /* If x0 and x1 are identical then x is also valid. */
13339 /* If x1 is identical to a subexpression of x0 then
13340 while checking x0, x1 has already been checked. Thus
13341 it is valid and so as x. */
13342 if (ARITHMETIC_P (x0
)
13343 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
13346 /* If x0 is identical to a subexpression of x1 then x is
13347 valid iff the rest of x1 is valid. */
13348 if (ARITHMETIC_P (x1
)
13349 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
13351 get_last_value_validate (&XEXP (x1
,
13352 x0
== XEXP (x1
, 0) ? 1 : 0),
13353 insn
, tick
, replace
);
13356 if (get_last_value_validate (&XEXP (x
, i
), insn
, tick
,
13360 else if (fmt
[i
] == 'E')
13361 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13362 if (get_last_value_validate (&XVECEXP (x
, i
, j
),
13363 insn
, tick
, replace
) == 0)
13367 /* If we haven't found a reason for it to be invalid, it is valid. */
13371 /* Get the last value assigned to X, if known. Some registers
13372 in the value may be replaced with (clobber (const_int 0)) if their value
13373 is known longer known reliably. */
13376 get_last_value (const_rtx x
)
13378 unsigned int regno
;
13380 reg_stat_type
*rsp
;
13382 /* If this is a non-paradoxical SUBREG, get the value of its operand and
13383 then convert it to the desired mode. If this is a paradoxical SUBREG,
13384 we cannot predict what values the "extra" bits might have. */
13385 if (GET_CODE (x
) == SUBREG
13386 && subreg_lowpart_p (x
)
13387 && !paradoxical_subreg_p (x
)
13388 && (value
= get_last_value (SUBREG_REG (x
))) != 0)
13389 return gen_lowpart (GET_MODE (x
), value
);
13395 rsp
= ®_stat
[regno
];
13396 value
= rsp
->last_set_value
;
13398 /* If we don't have a value, or if it isn't for this basic block and
13399 it's either a hard register, set more than once, or it's a live
13400 at the beginning of the function, return 0.
13402 Because if it's not live at the beginning of the function then the reg
13403 is always set before being used (is never used without being set).
13404 And, if it's set only once, and it's always set before use, then all
13405 uses must have the same last value, even if it's not from this basic
13409 || (rsp
->last_set_label
< label_tick_ebb_start
13410 && (regno
< FIRST_PSEUDO_REGISTER
13411 || regno
>= reg_n_sets_max
13412 || REG_N_SETS (regno
) != 1
13414 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
), regno
))))
13417 /* If the value was set in a later insn than the ones we are processing,
13418 we can't use it even if the register was only set once. */
13419 if (rsp
->last_set_label
== label_tick
13420 && DF_INSN_LUID (rsp
->last_set
) >= subst_low_luid
)
13423 /* If fewer bits were set than what we are asked for now, we cannot use
13425 if (GET_MODE_PRECISION (rsp
->last_set_mode
)
13426 < GET_MODE_PRECISION (GET_MODE (x
)))
13429 /* If the value has all its registers valid, return it. */
13430 if (get_last_value_validate (&value
, rsp
->last_set
, rsp
->last_set_label
, 0))
13433 /* Otherwise, make a copy and replace any invalid register with
13434 (clobber (const_int 0)). If that fails for some reason, return 0. */
13436 value
= copy_rtx (value
);
13437 if (get_last_value_validate (&value
, rsp
->last_set
, rsp
->last_set_label
, 1))
13443 /* Return nonzero if expression X refers to a REG or to memory
13444 that is set in an instruction more recent than FROM_LUID. */
13447 use_crosses_set_p (const_rtx x
, int from_luid
)
13451 enum rtx_code code
= GET_CODE (x
);
13455 unsigned int regno
= REGNO (x
);
13456 unsigned endreg
= END_REGNO (x
);
13458 #ifdef PUSH_ROUNDING
13459 /* Don't allow uses of the stack pointer to be moved,
13460 because we don't know whether the move crosses a push insn. */
13461 if (regno
== STACK_POINTER_REGNUM
&& PUSH_ARGS
)
13464 for (; regno
< endreg
; regno
++)
13466 reg_stat_type
*rsp
= ®_stat
[regno
];
13468 && rsp
->last_set_label
== label_tick
13469 && DF_INSN_LUID (rsp
->last_set
) > from_luid
)
13475 if (code
== MEM
&& mem_last_set
> from_luid
)
13478 fmt
= GET_RTX_FORMAT (code
);
13480 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
13485 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
13486 if (use_crosses_set_p (XVECEXP (x
, i
, j
), from_luid
))
13489 else if (fmt
[i
] == 'e'
13490 && use_crosses_set_p (XEXP (x
, i
), from_luid
))
13496 /* Define three variables used for communication between the following
13499 static unsigned int reg_dead_regno
, reg_dead_endregno
;
13500 static int reg_dead_flag
;
13502 /* Function called via note_stores from reg_dead_at_p.
13504 If DEST is within [reg_dead_regno, reg_dead_endregno), set
13505 reg_dead_flag to 1 if X is a CLOBBER and to -1 it is a SET. */
13508 reg_dead_at_p_1 (rtx dest
, const_rtx x
, void *data ATTRIBUTE_UNUSED
)
13510 unsigned int regno
, endregno
;
13515 regno
= REGNO (dest
);
13516 endregno
= END_REGNO (dest
);
13517 if (reg_dead_endregno
> regno
&& reg_dead_regno
< endregno
)
13518 reg_dead_flag
= (GET_CODE (x
) == CLOBBER
) ? 1 : -1;
13521 /* Return nonzero if REG is known to be dead at INSN.
13523 We scan backwards from INSN. If we hit a REG_DEAD note or a CLOBBER
13524 referencing REG, it is dead. If we hit a SET referencing REG, it is
13525 live. Otherwise, see if it is live or dead at the start of the basic
13526 block we are in. Hard regs marked as being live in NEWPAT_USED_REGS
13527 must be assumed to be always live. */
13530 reg_dead_at_p (rtx reg
, rtx_insn
*insn
)
13535 /* Set variables for reg_dead_at_p_1. */
13536 reg_dead_regno
= REGNO (reg
);
13537 reg_dead_endregno
= END_REGNO (reg
);
13541 /* Check that reg isn't mentioned in NEWPAT_USED_REGS. For fixed registers
13542 we allow the machine description to decide whether use-and-clobber
13543 patterns are OK. */
13544 if (reg_dead_regno
< FIRST_PSEUDO_REGISTER
)
13546 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
13547 if (!fixed_regs
[i
] && TEST_HARD_REG_BIT (newpat_used_regs
, i
))
13551 /* Scan backwards until we find a REG_DEAD note, SET, CLOBBER, or
13552 beginning of basic block. */
13553 block
= BLOCK_FOR_INSN (insn
);
13558 if (find_regno_note (insn
, REG_UNUSED
, reg_dead_regno
))
13561 note_stores (PATTERN (insn
), reg_dead_at_p_1
, NULL
);
13563 return reg_dead_flag
== 1 ? 1 : 0;
13565 if (find_regno_note (insn
, REG_DEAD
, reg_dead_regno
))
13569 if (insn
== BB_HEAD (block
))
13572 insn
= PREV_INSN (insn
);
13575 /* Look at live-in sets for the basic block that we were in. */
13576 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
13577 if (REGNO_REG_SET_P (df_get_live_in (block
), i
))
13583 /* Note hard registers in X that are used. */
13586 mark_used_regs_combine (rtx x
)
13588 RTX_CODE code
= GET_CODE (x
);
13589 unsigned int regno
;
13600 case ADDR_DIFF_VEC
:
13602 /* CC0 must die in the insn after it is set, so we don't need to take
13603 special note of it here. */
13608 /* If we are clobbering a MEM, mark any hard registers inside the
13609 address as used. */
13610 if (MEM_P (XEXP (x
, 0)))
13611 mark_used_regs_combine (XEXP (XEXP (x
, 0), 0));
13616 /* A hard reg in a wide mode may really be multiple registers.
13617 If so, mark all of them just like the first. */
13618 if (regno
< FIRST_PSEUDO_REGISTER
)
13620 /* None of this applies to the stack, frame or arg pointers. */
13621 if (regno
== STACK_POINTER_REGNUM
13622 || (!HARD_FRAME_POINTER_IS_FRAME_POINTER
13623 && regno
== HARD_FRAME_POINTER_REGNUM
)
13624 || (FRAME_POINTER_REGNUM
!= ARG_POINTER_REGNUM
13625 && regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
13626 || regno
== FRAME_POINTER_REGNUM
)
13629 add_to_hard_reg_set (&newpat_used_regs
, GET_MODE (x
), regno
);
13635 /* If setting a MEM, or a SUBREG of a MEM, then note any hard regs in
13637 rtx testreg
= SET_DEST (x
);
13639 while (GET_CODE (testreg
) == SUBREG
13640 || GET_CODE (testreg
) == ZERO_EXTRACT
13641 || GET_CODE (testreg
) == STRICT_LOW_PART
)
13642 testreg
= XEXP (testreg
, 0);
13644 if (MEM_P (testreg
))
13645 mark_used_regs_combine (XEXP (testreg
, 0));
13647 mark_used_regs_combine (SET_SRC (x
));
13655 /* Recursively scan the operands of this expression. */
13658 const char *fmt
= GET_RTX_FORMAT (code
);
13660 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
13663 mark_used_regs_combine (XEXP (x
, i
));
13664 else if (fmt
[i
] == 'E')
13668 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13669 mark_used_regs_combine (XVECEXP (x
, i
, j
));
13675 /* Remove register number REGNO from the dead registers list of INSN.
13677 Return the note used to record the death, if there was one. */
13680 remove_death (unsigned int regno
, rtx_insn
*insn
)
13682 rtx note
= find_regno_note (insn
, REG_DEAD
, regno
);
13685 remove_note (insn
, note
);
13690 /* For each register (hardware or pseudo) used within expression X, if its
13691 death is in an instruction with luid between FROM_LUID (inclusive) and
13692 TO_INSN (exclusive), put a REG_DEAD note for that register in the
13693 list headed by PNOTES.
13695 That said, don't move registers killed by maybe_kill_insn.
13697 This is done when X is being merged by combination into TO_INSN. These
13698 notes will then be distributed as needed. */
13701 move_deaths (rtx x
, rtx maybe_kill_insn
, int from_luid
, rtx_insn
*to_insn
,
13706 enum rtx_code code
= GET_CODE (x
);
13710 unsigned int regno
= REGNO (x
);
13711 rtx_insn
*where_dead
= reg_stat
[regno
].last_death
;
13713 /* Don't move the register if it gets killed in between from and to. */
13714 if (maybe_kill_insn
&& reg_set_p (x
, maybe_kill_insn
)
13715 && ! reg_referenced_p (x
, maybe_kill_insn
))
13719 && BLOCK_FOR_INSN (where_dead
) == BLOCK_FOR_INSN (to_insn
)
13720 && DF_INSN_LUID (where_dead
) >= from_luid
13721 && DF_INSN_LUID (where_dead
) < DF_INSN_LUID (to_insn
))
13723 rtx note
= remove_death (regno
, where_dead
);
13725 /* It is possible for the call above to return 0. This can occur
13726 when last_death points to I2 or I1 that we combined with.
13727 In that case make a new note.
13729 We must also check for the case where X is a hard register
13730 and NOTE is a death note for a range of hard registers
13731 including X. In that case, we must put REG_DEAD notes for
13732 the remaining registers in place of NOTE. */
13734 if (note
!= 0 && regno
< FIRST_PSEUDO_REGISTER
13735 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
13736 > GET_MODE_SIZE (GET_MODE (x
))))
13738 unsigned int deadregno
= REGNO (XEXP (note
, 0));
13739 unsigned int deadend
= END_REGNO (XEXP (note
, 0));
13740 unsigned int ourend
= END_REGNO (x
);
13743 for (i
= deadregno
; i
< deadend
; i
++)
13744 if (i
< regno
|| i
>= ourend
)
13745 add_reg_note (where_dead
, REG_DEAD
, regno_reg_rtx
[i
]);
13748 /* If we didn't find any note, or if we found a REG_DEAD note that
13749 covers only part of the given reg, and we have a multi-reg hard
13750 register, then to be safe we must check for REG_DEAD notes
13751 for each register other than the first. They could have
13752 their own REG_DEAD notes lying around. */
13753 else if ((note
== 0
13755 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
13756 < GET_MODE_SIZE (GET_MODE (x
)))))
13757 && regno
< FIRST_PSEUDO_REGISTER
13758 && REG_NREGS (x
) > 1)
13760 unsigned int ourend
= END_REGNO (x
);
13761 unsigned int i
, offset
;
13765 offset
= hard_regno_nregs
[regno
][GET_MODE (XEXP (note
, 0))];
13769 for (i
= regno
+ offset
; i
< ourend
; i
++)
13770 move_deaths (regno_reg_rtx
[i
],
13771 maybe_kill_insn
, from_luid
, to_insn
, &oldnotes
);
13774 if (note
!= 0 && GET_MODE (XEXP (note
, 0)) == GET_MODE (x
))
13776 XEXP (note
, 1) = *pnotes
;
13780 *pnotes
= alloc_reg_note (REG_DEAD
, x
, *pnotes
);
13786 else if (GET_CODE (x
) == SET
)
13788 rtx dest
= SET_DEST (x
);
13790 move_deaths (SET_SRC (x
), maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13792 /* In the case of a ZERO_EXTRACT, a STRICT_LOW_PART, or a SUBREG
13793 that accesses one word of a multi-word item, some
13794 piece of everything register in the expression is used by
13795 this insn, so remove any old death. */
13796 /* ??? So why do we test for equality of the sizes? */
13798 if (GET_CODE (dest
) == ZERO_EXTRACT
13799 || GET_CODE (dest
) == STRICT_LOW_PART
13800 || (GET_CODE (dest
) == SUBREG
13801 && (((GET_MODE_SIZE (GET_MODE (dest
))
13802 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
13803 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest
)))
13804 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))))
13806 move_deaths (dest
, maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13810 /* If this is some other SUBREG, we know it replaces the entire
13811 value, so use that as the destination. */
13812 if (GET_CODE (dest
) == SUBREG
)
13813 dest
= SUBREG_REG (dest
);
13815 /* If this is a MEM, adjust deaths of anything used in the address.
13816 For a REG (the only other possibility), the entire value is
13817 being replaced so the old value is not used in this insn. */
13820 move_deaths (XEXP (dest
, 0), maybe_kill_insn
, from_luid
,
13825 else if (GET_CODE (x
) == CLOBBER
)
13828 len
= GET_RTX_LENGTH (code
);
13829 fmt
= GET_RTX_FORMAT (code
);
13831 for (i
= 0; i
< len
; i
++)
13836 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
13837 move_deaths (XVECEXP (x
, i
, j
), maybe_kill_insn
, from_luid
,
13840 else if (fmt
[i
] == 'e')
13841 move_deaths (XEXP (x
, i
), maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13845 /* Return 1 if X is the target of a bit-field assignment in BODY, the
13846 pattern of an insn. X must be a REG. */
13849 reg_bitfield_target_p (rtx x
, rtx body
)
13853 if (GET_CODE (body
) == SET
)
13855 rtx dest
= SET_DEST (body
);
13857 unsigned int regno
, tregno
, endregno
, endtregno
;
13859 if (GET_CODE (dest
) == ZERO_EXTRACT
)
13860 target
= XEXP (dest
, 0);
13861 else if (GET_CODE (dest
) == STRICT_LOW_PART
)
13862 target
= SUBREG_REG (XEXP (dest
, 0));
13866 if (GET_CODE (target
) == SUBREG
)
13867 target
= SUBREG_REG (target
);
13869 if (!REG_P (target
))
13872 tregno
= REGNO (target
), regno
= REGNO (x
);
13873 if (tregno
>= FIRST_PSEUDO_REGISTER
|| regno
>= FIRST_PSEUDO_REGISTER
)
13874 return target
== x
;
13876 endtregno
= end_hard_regno (GET_MODE (target
), tregno
);
13877 endregno
= end_hard_regno (GET_MODE (x
), regno
);
13879 return endregno
> tregno
&& regno
< endtregno
;
13882 else if (GET_CODE (body
) == PARALLEL
)
13883 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
13884 if (reg_bitfield_target_p (x
, XVECEXP (body
, 0, i
)))
13890 /* Given a chain of REG_NOTES originally from FROM_INSN, try to place them
13891 as appropriate. I3 and I2 are the insns resulting from the combination
13892 insns including FROM (I2 may be zero).
13894 ELIM_I2 and ELIM_I1 are either zero or registers that we know will
13895 not need REG_DEAD notes because they are being substituted for. This
13896 saves searching in the most common cases.
13898 Each note in the list is either ignored or placed on some insns, depending
13899 on the type of note. */
13902 distribute_notes (rtx notes
, rtx_insn
*from_insn
, rtx_insn
*i3
, rtx_insn
*i2
,
13903 rtx elim_i2
, rtx elim_i1
, rtx elim_i0
)
13905 rtx note
, next_note
;
13907 rtx_insn
*tem_insn
;
13909 for (note
= notes
; note
; note
= next_note
)
13911 rtx_insn
*place
= 0, *place2
= 0;
13913 next_note
= XEXP (note
, 1);
13914 switch (REG_NOTE_KIND (note
))
13918 /* Doesn't matter much where we put this, as long as it's somewhere.
13919 It is preferable to keep these notes on branches, which is most
13920 likely to be i3. */
13924 case REG_NON_LOCAL_GOTO
:
13929 gcc_assert (i2
&& JUMP_P (i2
));
13934 case REG_EH_REGION
:
13935 /* These notes must remain with the call or trapping instruction. */
13938 else if (i2
&& CALL_P (i2
))
13942 gcc_assert (cfun
->can_throw_non_call_exceptions
);
13943 if (may_trap_p (i3
))
13945 else if (i2
&& may_trap_p (i2
))
13947 /* ??? Otherwise assume we've combined things such that we
13948 can now prove that the instructions can't trap. Drop the
13949 note in this case. */
13953 case REG_ARGS_SIZE
:
13954 /* ??? How to distribute between i3-i1. Assume i3 contains the
13955 entire adjustment. Assert i3 contains at least some adjust. */
13956 if (!noop_move_p (i3
))
13958 int old_size
, args_size
= INTVAL (XEXP (note
, 0));
13959 /* fixup_args_size_notes looks at REG_NORETURN note,
13960 so ensure the note is placed there first. */
13964 for (np
= &next_note
; *np
; np
= &XEXP (*np
, 1))
13965 if (REG_NOTE_KIND (*np
) == REG_NORETURN
)
13969 XEXP (n
, 1) = REG_NOTES (i3
);
13970 REG_NOTES (i3
) = n
;
13974 old_size
= fixup_args_size_notes (PREV_INSN (i3
), i3
, args_size
);
13975 /* emit_call_1 adds for !ACCUMULATE_OUTGOING_ARGS
13976 REG_ARGS_SIZE note to all noreturn calls, allow that here. */
13977 gcc_assert (old_size
!= args_size
13979 && !ACCUMULATE_OUTGOING_ARGS
13980 && find_reg_note (i3
, REG_NORETURN
, NULL_RTX
)));
13987 case REG_CALL_DECL
:
13988 /* These notes must remain with the call. It should not be
13989 possible for both I2 and I3 to be a call. */
13994 gcc_assert (i2
&& CALL_P (i2
));
14000 /* Any clobbers for i3 may still exist, and so we must process
14001 REG_UNUSED notes from that insn.
14003 Any clobbers from i2 or i1 can only exist if they were added by
14004 recog_for_combine. In that case, recog_for_combine created the
14005 necessary REG_UNUSED notes. Trying to keep any original
14006 REG_UNUSED notes from these insns can cause incorrect output
14007 if it is for the same register as the original i3 dest.
14008 In that case, we will notice that the register is set in i3,
14009 and then add a REG_UNUSED note for the destination of i3, which
14010 is wrong. However, it is possible to have REG_UNUSED notes from
14011 i2 or i1 for register which were both used and clobbered, so
14012 we keep notes from i2 or i1 if they will turn into REG_DEAD
14015 /* If this register is set or clobbered in I3, put the note there
14016 unless there is one already. */
14017 if (reg_set_p (XEXP (note
, 0), PATTERN (i3
)))
14019 if (from_insn
!= i3
)
14022 if (! (REG_P (XEXP (note
, 0))
14023 ? find_regno_note (i3
, REG_UNUSED
, REGNO (XEXP (note
, 0)))
14024 : find_reg_note (i3
, REG_UNUSED
, XEXP (note
, 0))))
14027 /* Otherwise, if this register is used by I3, then this register
14028 now dies here, so we must put a REG_DEAD note here unless there
14030 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
))
14031 && ! (REG_P (XEXP (note
, 0))
14032 ? find_regno_note (i3
, REG_DEAD
,
14033 REGNO (XEXP (note
, 0)))
14034 : find_reg_note (i3
, REG_DEAD
, XEXP (note
, 0))))
14036 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
14044 /* These notes say something about results of an insn. We can
14045 only support them if they used to be on I3 in which case they
14046 remain on I3. Otherwise they are ignored.
14048 If the note refers to an expression that is not a constant, we
14049 must also ignore the note since we cannot tell whether the
14050 equivalence is still true. It might be possible to do
14051 slightly better than this (we only have a problem if I2DEST
14052 or I1DEST is present in the expression), but it doesn't
14053 seem worth the trouble. */
14055 if (from_insn
== i3
14056 && (XEXP (note
, 0) == 0 || CONSTANT_P (XEXP (note
, 0))))
14061 /* These notes say something about how a register is used. They must
14062 be present on any use of the register in I2 or I3. */
14063 if (reg_mentioned_p (XEXP (note
, 0), PATTERN (i3
)))
14066 if (i2
&& reg_mentioned_p (XEXP (note
, 0), PATTERN (i2
)))
14075 case REG_LABEL_TARGET
:
14076 case REG_LABEL_OPERAND
:
14077 /* This can show up in several ways -- either directly in the
14078 pattern, or hidden off in the constant pool with (or without?)
14079 a REG_EQUAL note. */
14080 /* ??? Ignore the without-reg_equal-note problem for now. */
14081 if (reg_mentioned_p (XEXP (note
, 0), PATTERN (i3
))
14082 || ((tem_note
= find_reg_note (i3
, REG_EQUAL
, NULL_RTX
))
14083 && GET_CODE (XEXP (tem_note
, 0)) == LABEL_REF
14084 && label_ref_label (XEXP (tem_note
, 0)) == XEXP (note
, 0)))
14088 && (reg_mentioned_p (XEXP (note
, 0), PATTERN (i2
))
14089 || ((tem_note
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
))
14090 && GET_CODE (XEXP (tem_note
, 0)) == LABEL_REF
14091 && label_ref_label (XEXP (tem_note
, 0)) == XEXP (note
, 0))))
14099 /* For REG_LABEL_TARGET on a JUMP_P, we prefer to put the note
14100 as a JUMP_LABEL or decrement LABEL_NUSES if it's already
14102 if (place
&& JUMP_P (place
)
14103 && REG_NOTE_KIND (note
) == REG_LABEL_TARGET
14104 && (JUMP_LABEL (place
) == NULL
14105 || JUMP_LABEL (place
) == XEXP (note
, 0)))
14107 rtx label
= JUMP_LABEL (place
);
14110 JUMP_LABEL (place
) = XEXP (note
, 0);
14111 else if (LABEL_P (label
))
14112 LABEL_NUSES (label
)--;
14115 if (place2
&& JUMP_P (place2
)
14116 && REG_NOTE_KIND (note
) == REG_LABEL_TARGET
14117 && (JUMP_LABEL (place2
) == NULL
14118 || JUMP_LABEL (place2
) == XEXP (note
, 0)))
14120 rtx label
= JUMP_LABEL (place2
);
14123 JUMP_LABEL (place2
) = XEXP (note
, 0);
14124 else if (LABEL_P (label
))
14125 LABEL_NUSES (label
)--;
14131 /* This note says something about the value of a register prior
14132 to the execution of an insn. It is too much trouble to see
14133 if the note is still correct in all situations. It is better
14134 to simply delete it. */
14138 /* If we replaced the right hand side of FROM_INSN with a
14139 REG_EQUAL note, the original use of the dying register
14140 will not have been combined into I3 and I2. In such cases,
14141 FROM_INSN is guaranteed to be the first of the combined
14142 instructions, so we simply need to search back before
14143 FROM_INSN for the previous use or set of this register,
14144 then alter the notes there appropriately.
14146 If the register is used as an input in I3, it dies there.
14147 Similarly for I2, if it is nonzero and adjacent to I3.
14149 If the register is not used as an input in either I3 or I2
14150 and it is not one of the registers we were supposed to eliminate,
14151 there are two possibilities. We might have a non-adjacent I2
14152 or we might have somehow eliminated an additional register
14153 from a computation. For example, we might have had A & B where
14154 we discover that B will always be zero. In this case we will
14155 eliminate the reference to A.
14157 In both cases, we must search to see if we can find a previous
14158 use of A and put the death note there. */
14161 && from_insn
== i2mod
14162 && !reg_overlap_mentioned_p (XEXP (note
, 0), i2mod_new_rhs
))
14163 tem_insn
= from_insn
;
14167 && CALL_P (from_insn
)
14168 && find_reg_fusage (from_insn
, USE
, XEXP (note
, 0)))
14170 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
)))
14172 else if (i2
!= 0 && next_nonnote_nondebug_insn (i2
) == i3
14173 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
14175 else if ((rtx_equal_p (XEXP (note
, 0), elim_i2
)
14177 && reg_overlap_mentioned_p (XEXP (note
, 0),
14179 || rtx_equal_p (XEXP (note
, 0), elim_i1
)
14180 || rtx_equal_p (XEXP (note
, 0), elim_i0
))
14183 /* If the new I2 sets the same register that is marked dead
14184 in the note, we do not know where to put the note.
14186 if (i2
!= 0 && reg_set_p (XEXP (note
, 0), PATTERN (i2
)))
14192 basic_block bb
= this_basic_block
;
14194 for (tem_insn
= PREV_INSN (tem_insn
); place
== 0; tem_insn
= PREV_INSN (tem_insn
))
14196 if (!NONDEBUG_INSN_P (tem_insn
))
14198 if (tem_insn
== BB_HEAD (bb
))
14203 /* If the register is being set at TEM_INSN, see if that is all
14204 TEM_INSN is doing. If so, delete TEM_INSN. Otherwise, make this
14205 into a REG_UNUSED note instead. Don't delete sets to
14206 global register vars. */
14207 if ((REGNO (XEXP (note
, 0)) >= FIRST_PSEUDO_REGISTER
14208 || !global_regs
[REGNO (XEXP (note
, 0))])
14209 && reg_set_p (XEXP (note
, 0), PATTERN (tem_insn
)))
14211 rtx set
= single_set (tem_insn
);
14212 rtx inner_dest
= 0;
14213 rtx_insn
*cc0_setter
= NULL
;
14216 for (inner_dest
= SET_DEST (set
);
14217 (GET_CODE (inner_dest
) == STRICT_LOW_PART
14218 || GET_CODE (inner_dest
) == SUBREG
14219 || GET_CODE (inner_dest
) == ZERO_EXTRACT
);
14220 inner_dest
= XEXP (inner_dest
, 0))
14223 /* Verify that it was the set, and not a clobber that
14224 modified the register.
14226 CC0 targets must be careful to maintain setter/user
14227 pairs. If we cannot delete the setter due to side
14228 effects, mark the user with an UNUSED note instead
14231 if (set
!= 0 && ! side_effects_p (SET_SRC (set
))
14232 && rtx_equal_p (XEXP (note
, 0), inner_dest
)
14234 || (! reg_mentioned_p (cc0_rtx
, SET_SRC (set
))
14235 || ((cc0_setter
= prev_cc0_setter (tem_insn
)) != NULL
14236 && sets_cc0_p (PATTERN (cc0_setter
)) > 0))))
14238 /* Move the notes and links of TEM_INSN elsewhere.
14239 This might delete other dead insns recursively.
14240 First set the pattern to something that won't use
14242 rtx old_notes
= REG_NOTES (tem_insn
);
14244 PATTERN (tem_insn
) = pc_rtx
;
14245 REG_NOTES (tem_insn
) = NULL
;
14247 distribute_notes (old_notes
, tem_insn
, tem_insn
, NULL
,
14248 NULL_RTX
, NULL_RTX
, NULL_RTX
);
14249 distribute_links (LOG_LINKS (tem_insn
));
14251 SET_INSN_DELETED (tem_insn
);
14252 if (tem_insn
== i2
)
14255 /* Delete the setter too. */
14258 PATTERN (cc0_setter
) = pc_rtx
;
14259 old_notes
= REG_NOTES (cc0_setter
);
14260 REG_NOTES (cc0_setter
) = NULL
;
14262 distribute_notes (old_notes
, cc0_setter
,
14264 NULL_RTX
, NULL_RTX
, NULL_RTX
);
14265 distribute_links (LOG_LINKS (cc0_setter
));
14267 SET_INSN_DELETED (cc0_setter
);
14268 if (cc0_setter
== i2
)
14274 PUT_REG_NOTE_KIND (note
, REG_UNUSED
);
14276 /* If there isn't already a REG_UNUSED note, put one
14277 here. Do not place a REG_DEAD note, even if
14278 the register is also used here; that would not
14279 match the algorithm used in lifetime analysis
14280 and can cause the consistency check in the
14281 scheduler to fail. */
14282 if (! find_regno_note (tem_insn
, REG_UNUSED
,
14283 REGNO (XEXP (note
, 0))))
14288 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (tem_insn
))
14289 || (CALL_P (tem_insn
)
14290 && find_reg_fusage (tem_insn
, USE
, XEXP (note
, 0))))
14294 /* If we are doing a 3->2 combination, and we have a
14295 register which formerly died in i3 and was not used
14296 by i2, which now no longer dies in i3 and is used in
14297 i2 but does not die in i2, and place is between i2
14298 and i3, then we may need to move a link from place to
14300 if (i2
&& DF_INSN_LUID (place
) > DF_INSN_LUID (i2
)
14302 && DF_INSN_LUID (from_insn
) > DF_INSN_LUID (i2
)
14303 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
14305 struct insn_link
*links
= LOG_LINKS (place
);
14306 LOG_LINKS (place
) = NULL
;
14307 distribute_links (links
);
14312 if (tem_insn
== BB_HEAD (bb
))
14318 /* If the register is set or already dead at PLACE, we needn't do
14319 anything with this note if it is still a REG_DEAD note.
14320 We check here if it is set at all, not if is it totally replaced,
14321 which is what `dead_or_set_p' checks, so also check for it being
14324 if (place
&& REG_NOTE_KIND (note
) == REG_DEAD
)
14326 unsigned int regno
= REGNO (XEXP (note
, 0));
14327 reg_stat_type
*rsp
= ®_stat
[regno
];
14329 if (dead_or_set_p (place
, XEXP (note
, 0))
14330 || reg_bitfield_target_p (XEXP (note
, 0), PATTERN (place
)))
14332 /* Unless the register previously died in PLACE, clear
14333 last_death. [I no longer understand why this is
14335 if (rsp
->last_death
!= place
)
14336 rsp
->last_death
= 0;
14340 rsp
->last_death
= place
;
14342 /* If this is a death note for a hard reg that is occupying
14343 multiple registers, ensure that we are still using all
14344 parts of the object. If we find a piece of the object
14345 that is unused, we must arrange for an appropriate REG_DEAD
14346 note to be added for it. However, we can't just emit a USE
14347 and tag the note to it, since the register might actually
14348 be dead; so we recourse, and the recursive call then finds
14349 the previous insn that used this register. */
14351 if (place
&& REG_NREGS (XEXP (note
, 0)) > 1)
14353 unsigned int endregno
= END_REGNO (XEXP (note
, 0));
14354 bool all_used
= true;
14357 for (i
= regno
; i
< endregno
; i
++)
14358 if ((! refers_to_regno_p (i
, PATTERN (place
))
14359 && ! find_regno_fusage (place
, USE
, i
))
14360 || dead_or_set_regno_p (place
, i
))
14368 /* Put only REG_DEAD notes for pieces that are
14369 not already dead or set. */
14371 for (i
= regno
; i
< endregno
;
14372 i
+= hard_regno_nregs
[i
][reg_raw_mode
[i
]])
14374 rtx piece
= regno_reg_rtx
[i
];
14375 basic_block bb
= this_basic_block
;
14377 if (! dead_or_set_p (place
, piece
)
14378 && ! reg_bitfield_target_p (piece
,
14381 rtx new_note
= alloc_reg_note (REG_DEAD
, piece
,
14384 distribute_notes (new_note
, place
, place
,
14385 NULL
, NULL_RTX
, NULL_RTX
,
14388 else if (! refers_to_regno_p (i
, PATTERN (place
))
14389 && ! find_regno_fusage (place
, USE
, i
))
14390 for (tem_insn
= PREV_INSN (place
); ;
14391 tem_insn
= PREV_INSN (tem_insn
))
14393 if (!NONDEBUG_INSN_P (tem_insn
))
14395 if (tem_insn
== BB_HEAD (bb
))
14399 if (dead_or_set_p (tem_insn
, piece
)
14400 || reg_bitfield_target_p (piece
,
14401 PATTERN (tem_insn
)))
14403 add_reg_note (tem_insn
, REG_UNUSED
, piece
);
14416 /* Any other notes should not be present at this point in the
14418 gcc_unreachable ();
14423 XEXP (note
, 1) = REG_NOTES (place
);
14424 REG_NOTES (place
) = note
;
14428 add_shallow_copy_of_reg_note (place2
, note
);
14432 /* Similarly to above, distribute the LOG_LINKS that used to be present on
14433 I3, I2, and I1 to new locations. This is also called to add a link
14434 pointing at I3 when I3's destination is changed. */
14437 distribute_links (struct insn_link
*links
)
14439 struct insn_link
*link
, *next_link
;
14441 for (link
= links
; link
; link
= next_link
)
14443 rtx_insn
*place
= 0;
14447 next_link
= link
->next
;
14449 /* If the insn that this link points to is a NOTE, ignore it. */
14450 if (NOTE_P (link
->insn
))
14454 rtx pat
= PATTERN (link
->insn
);
14455 if (GET_CODE (pat
) == SET
)
14457 else if (GET_CODE (pat
) == PARALLEL
)
14460 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
14462 set
= XVECEXP (pat
, 0, i
);
14463 if (GET_CODE (set
) != SET
)
14466 reg
= SET_DEST (set
);
14467 while (GET_CODE (reg
) == ZERO_EXTRACT
14468 || GET_CODE (reg
) == STRICT_LOW_PART
14469 || GET_CODE (reg
) == SUBREG
)
14470 reg
= XEXP (reg
, 0);
14475 if (REGNO (reg
) == link
->regno
)
14478 if (i
== XVECLEN (pat
, 0))
14484 reg
= SET_DEST (set
);
14486 while (GET_CODE (reg
) == ZERO_EXTRACT
14487 || GET_CODE (reg
) == STRICT_LOW_PART
14488 || GET_CODE (reg
) == SUBREG
)
14489 reg
= XEXP (reg
, 0);
14491 /* A LOG_LINK is defined as being placed on the first insn that uses
14492 a register and points to the insn that sets the register. Start
14493 searching at the next insn after the target of the link and stop
14494 when we reach a set of the register or the end of the basic block.
14496 Note that this correctly handles the link that used to point from
14497 I3 to I2. Also note that not much searching is typically done here
14498 since most links don't point very far away. */
14500 for (insn
= NEXT_INSN (link
->insn
);
14501 (insn
&& (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
14502 || BB_HEAD (this_basic_block
->next_bb
) != insn
));
14503 insn
= NEXT_INSN (insn
))
14504 if (DEBUG_INSN_P (insn
))
14506 else if (INSN_P (insn
) && reg_overlap_mentioned_p (reg
, PATTERN (insn
)))
14508 if (reg_referenced_p (reg
, PATTERN (insn
)))
14512 else if (CALL_P (insn
)
14513 && find_reg_fusage (insn
, USE
, reg
))
14518 else if (INSN_P (insn
) && reg_set_p (reg
, insn
))
14521 /* If we found a place to put the link, place it there unless there
14522 is already a link to the same insn as LINK at that point. */
14526 struct insn_link
*link2
;
14528 FOR_EACH_LOG_LINK (link2
, place
)
14529 if (link2
->insn
== link
->insn
&& link2
->regno
== link
->regno
)
14534 link
->next
= LOG_LINKS (place
);
14535 LOG_LINKS (place
) = link
;
14537 /* Set added_links_insn to the earliest insn we added a
14539 if (added_links_insn
== 0
14540 || DF_INSN_LUID (added_links_insn
) > DF_INSN_LUID (place
))
14541 added_links_insn
= place
;
14547 /* Check for any register or memory mentioned in EQUIV that is not
14548 mentioned in EXPR. This is used to restrict EQUIV to "specializations"
14549 of EXPR where some registers may have been replaced by constants. */
14552 unmentioned_reg_p (rtx equiv
, rtx expr
)
14554 subrtx_iterator::array_type array
;
14555 FOR_EACH_SUBRTX (iter
, array
, equiv
, NONCONST
)
14557 const_rtx x
= *iter
;
14558 if ((REG_P (x
) || MEM_P (x
))
14559 && !reg_mentioned_p (x
, expr
))
14565 DEBUG_FUNCTION
void
14566 dump_combine_stats (FILE *file
)
14570 ";; Combiner statistics: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n\n",
14571 combine_attempts
, combine_merges
, combine_extras
, combine_successes
);
14575 dump_combine_total_stats (FILE *file
)
14579 "\n;; Combiner totals: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n",
14580 total_attempts
, total_merges
, total_extras
, total_successes
);
14583 /* Try combining insns through substitution. */
14584 static unsigned int
14585 rest_of_handle_combine (void)
14587 int rebuild_jump_labels_after_combine
;
14589 df_set_flags (DF_LR_RUN_DCE
+ DF_DEFER_INSN_RESCAN
);
14590 df_note_add_problem ();
14593 regstat_init_n_sets_and_refs ();
14594 reg_n_sets_max
= max_reg_num ();
14596 rebuild_jump_labels_after_combine
14597 = combine_instructions (get_insns (), max_reg_num ());
14599 /* Combining insns may have turned an indirect jump into a
14600 direct jump. Rebuild the JUMP_LABEL fields of jumping
14602 if (rebuild_jump_labels_after_combine
)
14604 if (dom_info_available_p (CDI_DOMINATORS
))
14605 free_dominance_info (CDI_DOMINATORS
);
14606 timevar_push (TV_JUMP
);
14607 rebuild_jump_labels (get_insns ());
14609 timevar_pop (TV_JUMP
);
14612 regstat_free_n_sets_and_refs ();
14618 const pass_data pass_data_combine
=
14620 RTL_PASS
, /* type */
14621 "combine", /* name */
14622 OPTGROUP_NONE
, /* optinfo_flags */
14623 TV_COMBINE
, /* tv_id */
14624 PROP_cfglayout
, /* properties_required */
14625 0, /* properties_provided */
14626 0, /* properties_destroyed */
14627 0, /* todo_flags_start */
14628 TODO_df_finish
, /* todo_flags_finish */
14631 class pass_combine
: public rtl_opt_pass
14634 pass_combine (gcc::context
*ctxt
)
14635 : rtl_opt_pass (pass_data_combine
, ctxt
)
14638 /* opt_pass methods: */
14639 virtual bool gate (function
*) { return (optimize
> 0); }
14640 virtual unsigned int execute (function
*)
14642 return rest_of_handle_combine ();
14645 }; // class pass_combine
14647 } // anon namespace
14650 make_pass_combine (gcc::context
*ctxt
)
14652 return new pass_combine (ctxt
);