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"
93 #include "stor-layout.h"
95 #include "cfgcleanup.h"
96 /* Include expr.h after insn-config.h so we get HAVE_conditional_move. */
98 #include "insn-attr.h"
99 #include "rtlhooks-def.h"
101 #include "tree-pass.h"
102 #include "valtrack.h"
103 #include "rtl-iter.h"
104 #include "print-rtl.h"
106 #ifndef LOAD_EXTEND_OP
107 #define LOAD_EXTEND_OP(M) UNKNOWN
110 /* Number of attempts to combine instructions in this function. */
112 static int combine_attempts
;
114 /* Number of attempts that got as far as substitution in this function. */
116 static int combine_merges
;
118 /* Number of instructions combined with added SETs in this function. */
120 static int combine_extras
;
122 /* Number of instructions combined in this function. */
124 static int combine_successes
;
126 /* Totals over entire compilation. */
128 static int total_attempts
, total_merges
, total_extras
, total_successes
;
130 /* combine_instructions may try to replace the right hand side of the
131 second instruction with the value of an associated REG_EQUAL note
132 before throwing it at try_combine. That is problematic when there
133 is a REG_DEAD note for a register used in the old right hand side
134 and can cause distribute_notes to do wrong things. This is the
135 second instruction if it has been so modified, null otherwise. */
137 static rtx_insn
*i2mod
;
139 /* When I2MOD is nonnull, this is a copy of the old right hand side. */
141 static rtx i2mod_old_rhs
;
143 /* When I2MOD is nonnull, this is a copy of the new right hand side. */
145 static rtx i2mod_new_rhs
;
147 struct reg_stat_type
{
148 /* Record last point of death of (hard or pseudo) register n. */
149 rtx_insn
*last_death
;
151 /* Record last point of modification of (hard or pseudo) register n. */
154 /* The next group of fields allows the recording of the last value assigned
155 to (hard or pseudo) register n. We use this information to see if an
156 operation being processed is redundant given a prior operation performed
157 on the register. For example, an `and' with a constant is redundant if
158 all the zero bits are already known to be turned off.
160 We use an approach similar to that used by cse, but change it in the
163 (1) We do not want to reinitialize at each label.
164 (2) It is useful, but not critical, to know the actual value assigned
165 to a register. Often just its form is helpful.
167 Therefore, we maintain the following fields:
169 last_set_value the last value assigned
170 last_set_label records the value of label_tick when the
171 register was assigned
172 last_set_table_tick records the value of label_tick when a
173 value using the register is assigned
174 last_set_invalid set to nonzero when it is not valid
175 to use the value of this register in some
178 To understand the usage of these tables, it is important to understand
179 the distinction between the value in last_set_value being valid and
180 the register being validly contained in some other expression in the
183 (The next two parameters are out of date).
185 reg_stat[i].last_set_value is valid if it is nonzero, and either
186 reg_n_sets[i] is 1 or reg_stat[i].last_set_label == label_tick.
188 Register I may validly appear in any expression returned for the value
189 of another register if reg_n_sets[i] is 1. It may also appear in the
190 value for register J if reg_stat[j].last_set_invalid is zero, or
191 reg_stat[i].last_set_label < reg_stat[j].last_set_label.
193 If an expression is found in the table containing a register which may
194 not validly appear in an expression, the register is replaced by
195 something that won't match, (clobber (const_int 0)). */
197 /* Record last value assigned to (hard or pseudo) register n. */
201 /* Record the value of label_tick when an expression involving register n
202 is placed in last_set_value. */
204 int last_set_table_tick
;
206 /* Record the value of label_tick when the value for register n is placed in
211 /* These fields are maintained in parallel with last_set_value and are
212 used to store the mode in which the register was last set, the bits
213 that were known to be zero when it was last set, and the number of
214 sign bits copies it was known to have when it was last set. */
216 unsigned HOST_WIDE_INT last_set_nonzero_bits
;
217 char last_set_sign_bit_copies
;
218 ENUM_BITFIELD(machine_mode
) last_set_mode
: 8;
220 /* Set nonzero if references to register n in expressions should not be
221 used. last_set_invalid is set nonzero when this register is being
222 assigned to and last_set_table_tick == label_tick. */
224 char last_set_invalid
;
226 /* Some registers that are set more than once and used in more than one
227 basic block are nevertheless always set in similar ways. For example,
228 a QImode register may be loaded from memory in two places on a machine
229 where byte loads zero extend.
231 We record in the following fields if a register has some leading bits
232 that are always equal to the sign bit, and what we know about the
233 nonzero bits of a register, specifically which bits are known to be
236 If an entry is zero, it means that we don't know anything special. */
238 unsigned char sign_bit_copies
;
240 unsigned HOST_WIDE_INT nonzero_bits
;
242 /* Record the value of the label_tick when the last truncation
243 happened. The field truncated_to_mode is only valid if
244 truncation_label == label_tick. */
246 int truncation_label
;
248 /* Record the last truncation seen for this register. If truncation
249 is not a nop to this mode we might be able to save an explicit
250 truncation if we know that value already contains a truncated
253 ENUM_BITFIELD(machine_mode
) truncated_to_mode
: 8;
257 static vec
<reg_stat_type
> reg_stat
;
259 /* One plus the highest pseudo for which we track REG_N_SETS.
260 regstat_init_n_sets_and_refs allocates the array for REG_N_SETS just once,
261 but during combine_split_insns new pseudos can be created. As we don't have
262 updated DF information in that case, it is hard to initialize the array
263 after growing. The combiner only cares about REG_N_SETS (regno) == 1,
264 so instead of growing the arrays, just assume all newly created pseudos
265 during combine might be set multiple times. */
267 static unsigned int reg_n_sets_max
;
269 /* Record the luid of the last insn that invalidated memory
270 (anything that writes memory, and subroutine calls, but not pushes). */
272 static int mem_last_set
;
274 /* Record the luid of the last CALL_INSN
275 so we can tell whether a potential combination crosses any calls. */
277 static int last_call_luid
;
279 /* When `subst' is called, this is the insn that is being modified
280 (by combining in a previous insn). The PATTERN of this insn
281 is still the old pattern partially modified and it should not be
282 looked at, but this may be used to examine the successors of the insn
283 to judge whether a simplification is valid. */
285 static rtx_insn
*subst_insn
;
287 /* This is the lowest LUID that `subst' is currently dealing with.
288 get_last_value will not return a value if the register was set at or
289 after this LUID. If not for this mechanism, we could get confused if
290 I2 or I1 in try_combine were an insn that used the old value of a register
291 to obtain a new value. In that case, we might erroneously get the
292 new value of the register when we wanted the old one. */
294 static int subst_low_luid
;
296 /* This contains any hard registers that are used in newpat; reg_dead_at_p
297 must consider all these registers to be always live. */
299 static HARD_REG_SET newpat_used_regs
;
301 /* This is an insn to which a LOG_LINKS entry has been added. If this
302 insn is the earlier than I2 or I3, combine should rescan starting at
305 static rtx_insn
*added_links_insn
;
307 /* Basic block in which we are performing combines. */
308 static basic_block this_basic_block
;
309 static bool optimize_this_for_speed_p
;
312 /* Length of the currently allocated uid_insn_cost array. */
314 static int max_uid_known
;
316 /* The following array records the insn_rtx_cost for every insn
317 in the instruction stream. */
319 static int *uid_insn_cost
;
321 /* The following array records the LOG_LINKS for every insn in the
322 instruction stream as struct insn_link pointers. */
327 struct insn_link
*next
;
330 static struct insn_link
**uid_log_links
;
332 #define INSN_COST(INSN) (uid_insn_cost[INSN_UID (INSN)])
333 #define LOG_LINKS(INSN) (uid_log_links[INSN_UID (INSN)])
335 #define FOR_EACH_LOG_LINK(L, INSN) \
336 for ((L) = LOG_LINKS (INSN); (L); (L) = (L)->next)
338 /* Links for LOG_LINKS are allocated from this obstack. */
340 static struct obstack insn_link_obstack
;
342 /* Allocate a link. */
344 static inline struct insn_link
*
345 alloc_insn_link (rtx_insn
*insn
, unsigned int regno
, struct insn_link
*next
)
348 = (struct insn_link
*) obstack_alloc (&insn_link_obstack
,
349 sizeof (struct insn_link
));
356 /* Incremented for each basic block. */
358 static int label_tick
;
360 /* Reset to label_tick for each extended basic block in scanning order. */
362 static int label_tick_ebb_start
;
364 /* Mode used to compute significance in reg_stat[].nonzero_bits. It is the
365 largest integer mode that can fit in HOST_BITS_PER_WIDE_INT. */
367 static machine_mode nonzero_bits_mode
;
369 /* Nonzero when reg_stat[].nonzero_bits and reg_stat[].sign_bit_copies can
370 be safely used. It is zero while computing them and after combine has
371 completed. This former test prevents propagating values based on
372 previously set values, which can be incorrect if a variable is modified
375 static int nonzero_sign_valid
;
378 /* Record one modification to rtl structure
379 to be undone by storing old_contents into *where. */
381 enum undo_kind
{ UNDO_RTX
, UNDO_INT
, UNDO_MODE
, UNDO_LINKS
};
387 union { rtx r
; int i
; machine_mode m
; struct insn_link
*l
; } old_contents
;
388 union { rtx
*r
; int *i
; struct insn_link
**l
; } where
;
391 /* Record a bunch of changes to be undone, up to MAX_UNDO of them.
392 num_undo says how many are currently recorded.
394 other_insn is nonzero if we have modified some other insn in the process
395 of working on subst_insn. It must be verified too. */
401 rtx_insn
*other_insn
;
404 static struct undobuf undobuf
;
406 /* Number of times the pseudo being substituted for
407 was found and replaced. */
409 static int n_occurrences
;
411 static rtx
reg_nonzero_bits_for_combine (const_rtx
, machine_mode
, const_rtx
,
413 unsigned HOST_WIDE_INT
,
414 unsigned HOST_WIDE_INT
*);
415 static rtx
reg_num_sign_bit_copies_for_combine (const_rtx
, machine_mode
, const_rtx
,
417 unsigned int, unsigned int *);
418 static void do_SUBST (rtx
*, rtx
);
419 static void do_SUBST_INT (int *, int);
420 static void init_reg_last (void);
421 static void setup_incoming_promotions (rtx_insn
*);
422 static void set_nonzero_bits_and_sign_copies (rtx
, const_rtx
, void *);
423 static int cant_combine_insn_p (rtx_insn
*);
424 static int can_combine_p (rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx_insn
*,
425 rtx_insn
*, rtx_insn
*, rtx
*, rtx
*);
426 static int combinable_i3pat (rtx_insn
*, rtx
*, rtx
, rtx
, rtx
, int, int, rtx
*);
427 static int contains_muldiv (rtx
);
428 static rtx_insn
*try_combine (rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx_insn
*,
430 static void undo_all (void);
431 static void undo_commit (void);
432 static rtx
*find_split_point (rtx
*, rtx_insn
*, bool);
433 static rtx
subst (rtx
, rtx
, rtx
, int, int, int);
434 static rtx
combine_simplify_rtx (rtx
, machine_mode
, int, int);
435 static rtx
simplify_if_then_else (rtx
);
436 static rtx
simplify_set (rtx
);
437 static rtx
simplify_logical (rtx
);
438 static rtx
expand_compound_operation (rtx
);
439 static const_rtx
expand_field_assignment (const_rtx
);
440 static rtx
make_extraction (machine_mode
, rtx
, HOST_WIDE_INT
,
441 rtx
, unsigned HOST_WIDE_INT
, int, int, int);
442 static rtx
extract_left_shift (rtx
, int);
443 static int get_pos_from_mask (unsigned HOST_WIDE_INT
,
444 unsigned HOST_WIDE_INT
*);
445 static rtx
canon_reg_for_combine (rtx
, rtx
);
446 static rtx
force_to_mode (rtx
, machine_mode
,
447 unsigned HOST_WIDE_INT
, int);
448 static rtx
if_then_else_cond (rtx
, rtx
*, rtx
*);
449 static rtx
known_cond (rtx
, enum rtx_code
, rtx
, rtx
);
450 static int rtx_equal_for_field_assignment_p (rtx
, rtx
, bool = false);
451 static rtx
make_field_assignment (rtx
);
452 static rtx
apply_distributive_law (rtx
);
453 static rtx
distribute_and_simplify_rtx (rtx
, int);
454 static rtx
simplify_and_const_int_1 (machine_mode
, rtx
,
455 unsigned HOST_WIDE_INT
);
456 static rtx
simplify_and_const_int (rtx
, machine_mode
, rtx
,
457 unsigned HOST_WIDE_INT
);
458 static int merge_outer_ops (enum rtx_code
*, HOST_WIDE_INT
*, enum rtx_code
,
459 HOST_WIDE_INT
, machine_mode
, int *);
460 static rtx
simplify_shift_const_1 (enum rtx_code
, machine_mode
, rtx
, int);
461 static rtx
simplify_shift_const (rtx
, enum rtx_code
, machine_mode
, rtx
,
463 static int recog_for_combine (rtx
*, rtx_insn
*, rtx
*);
464 static rtx
gen_lowpart_for_combine (machine_mode
, rtx
);
465 static enum rtx_code
simplify_compare_const (enum rtx_code
, machine_mode
,
467 static enum rtx_code
simplify_comparison (enum rtx_code
, rtx
*, rtx
*);
468 static void update_table_tick (rtx
);
469 static void record_value_for_reg (rtx
, rtx_insn
*, rtx
);
470 static void check_promoted_subreg (rtx_insn
*, rtx
);
471 static void record_dead_and_set_regs_1 (rtx
, const_rtx
, void *);
472 static void record_dead_and_set_regs (rtx_insn
*);
473 static int get_last_value_validate (rtx
*, rtx_insn
*, int, int);
474 static rtx
get_last_value (const_rtx
);
475 static int use_crosses_set_p (const_rtx
, int);
476 static void reg_dead_at_p_1 (rtx
, const_rtx
, void *);
477 static int reg_dead_at_p (rtx
, rtx_insn
*);
478 static void move_deaths (rtx
, rtx
, int, rtx_insn
*, rtx
*);
479 static int reg_bitfield_target_p (rtx
, rtx
);
480 static void distribute_notes (rtx
, rtx_insn
*, rtx_insn
*, rtx_insn
*, rtx
, rtx
, rtx
);
481 static void distribute_links (struct insn_link
*);
482 static void mark_used_regs_combine (rtx
);
483 static void record_promoted_value (rtx_insn
*, rtx
);
484 static bool unmentioned_reg_p (rtx
, rtx
);
485 static void record_truncated_values (rtx
*, void *);
486 static bool reg_truncated_to_mode (machine_mode
, const_rtx
);
487 static rtx
gen_lowpart_or_truncate (machine_mode
, rtx
);
490 /* It is not safe to use ordinary gen_lowpart in combine.
491 See comments in gen_lowpart_for_combine. */
492 #undef RTL_HOOKS_GEN_LOWPART
493 #define RTL_HOOKS_GEN_LOWPART gen_lowpart_for_combine
495 /* Our implementation of gen_lowpart never emits a new pseudo. */
496 #undef RTL_HOOKS_GEN_LOWPART_NO_EMIT
497 #define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_for_combine
499 #undef RTL_HOOKS_REG_NONZERO_REG_BITS
500 #define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_for_combine
502 #undef RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES
503 #define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_for_combine
505 #undef RTL_HOOKS_REG_TRUNCATED_TO_MODE
506 #define RTL_HOOKS_REG_TRUNCATED_TO_MODE reg_truncated_to_mode
508 static const struct rtl_hooks combine_rtl_hooks
= RTL_HOOKS_INITIALIZER
;
511 /* Convenience wrapper for the canonicalize_comparison target hook.
512 Target hooks cannot use enum rtx_code. */
514 target_canonicalize_comparison (enum rtx_code
*code
, rtx
*op0
, rtx
*op1
,
515 bool op0_preserve_value
)
517 int code_int
= (int)*code
;
518 targetm
.canonicalize_comparison (&code_int
, op0
, op1
, op0_preserve_value
);
519 *code
= (enum rtx_code
)code_int
;
522 /* Try to split PATTERN found in INSN. This returns NULL_RTX if
523 PATTERN can not be split. Otherwise, it returns an insn sequence.
524 This is a wrapper around split_insns which ensures that the
525 reg_stat vector is made larger if the splitter creates a new
529 combine_split_insns (rtx pattern
, rtx_insn
*insn
)
534 ret
= split_insns (pattern
, insn
);
535 nregs
= max_reg_num ();
536 if (nregs
> reg_stat
.length ())
537 reg_stat
.safe_grow_cleared (nregs
);
541 /* This is used by find_single_use to locate an rtx in LOC that
542 contains exactly one use of DEST, which is typically either a REG
543 or CC0. It returns a pointer to the innermost rtx expression
544 containing DEST. Appearances of DEST that are being used to
545 totally replace it are not counted. */
548 find_single_use_1 (rtx dest
, rtx
*loc
)
551 enum rtx_code code
= GET_CODE (x
);
567 /* If the destination is anything other than CC0, PC, a REG or a SUBREG
568 of a REG that occupies all of the REG, the insn uses DEST if
569 it is mentioned in the destination or the source. Otherwise, we
570 need just check the source. */
571 if (GET_CODE (SET_DEST (x
)) != CC0
572 && GET_CODE (SET_DEST (x
)) != PC
573 && !REG_P (SET_DEST (x
))
574 && ! (GET_CODE (SET_DEST (x
)) == SUBREG
575 && REG_P (SUBREG_REG (SET_DEST (x
)))
576 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x
))))
577 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
578 == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x
)))
579 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
))))
582 return find_single_use_1 (dest
, &SET_SRC (x
));
586 return find_single_use_1 (dest
, &XEXP (x
, 0));
592 /* If it wasn't one of the common cases above, check each expression and
593 vector of this code. Look for a unique usage of DEST. */
595 fmt
= GET_RTX_FORMAT (code
);
596 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
600 if (dest
== XEXP (x
, i
)
601 || (REG_P (dest
) && REG_P (XEXP (x
, i
))
602 && REGNO (dest
) == REGNO (XEXP (x
, i
))))
605 this_result
= find_single_use_1 (dest
, &XEXP (x
, i
));
608 result
= this_result
;
609 else if (this_result
)
610 /* Duplicate usage. */
613 else if (fmt
[i
] == 'E')
617 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
619 if (XVECEXP (x
, i
, j
) == dest
621 && REG_P (XVECEXP (x
, i
, j
))
622 && REGNO (XVECEXP (x
, i
, j
)) == REGNO (dest
)))
625 this_result
= find_single_use_1 (dest
, &XVECEXP (x
, i
, j
));
628 result
= this_result
;
629 else if (this_result
)
639 /* See if DEST, produced in INSN, is used only a single time in the
640 sequel. If so, return a pointer to the innermost rtx expression in which
643 If PLOC is nonzero, *PLOC is set to the insn containing the single use.
645 If DEST is cc0_rtx, we look only at the next insn. In that case, we don't
646 care about REG_DEAD notes or LOG_LINKS.
648 Otherwise, we find the single use by finding an insn that has a
649 LOG_LINKS pointing at INSN and has a REG_DEAD note for DEST. If DEST is
650 only referenced once in that insn, we know that it must be the first
651 and last insn referencing DEST. */
654 find_single_use (rtx dest
, rtx_insn
*insn
, rtx_insn
**ploc
)
659 struct insn_link
*link
;
663 next
= NEXT_INSN (insn
);
665 || (!NONJUMP_INSN_P (next
) && !JUMP_P (next
)))
668 result
= find_single_use_1 (dest
, &PATTERN (next
));
677 bb
= BLOCK_FOR_INSN (insn
);
678 for (next
= NEXT_INSN (insn
);
679 next
&& BLOCK_FOR_INSN (next
) == bb
;
680 next
= NEXT_INSN (next
))
681 if (INSN_P (next
) && dead_or_set_p (next
, dest
))
683 FOR_EACH_LOG_LINK (link
, next
)
684 if (link
->insn
== insn
&& link
->regno
== REGNO (dest
))
689 result
= find_single_use_1 (dest
, &PATTERN (next
));
699 /* Substitute NEWVAL, an rtx expression, into INTO, a place in some
700 insn. The substitution can be undone by undo_all. If INTO is already
701 set to NEWVAL, do not record this change. Because computing NEWVAL might
702 also call SUBST, we have to compute it before we put anything into
706 do_SUBST (rtx
*into
, rtx newval
)
711 if (oldval
== newval
)
714 /* We'd like to catch as many invalid transformations here as
715 possible. Unfortunately, there are way too many mode changes
716 that are perfectly valid, so we'd waste too much effort for
717 little gain doing the checks here. Focus on catching invalid
718 transformations involving integer constants. */
719 if (GET_MODE_CLASS (GET_MODE (oldval
)) == MODE_INT
720 && CONST_INT_P (newval
))
722 /* Sanity check that we're replacing oldval with a CONST_INT
723 that is a valid sign-extension for the original mode. */
724 gcc_assert (INTVAL (newval
)
725 == trunc_int_for_mode (INTVAL (newval
), GET_MODE (oldval
)));
727 /* Replacing the operand of a SUBREG or a ZERO_EXTEND with a
728 CONST_INT is not valid, because after the replacement, the
729 original mode would be gone. Unfortunately, we can't tell
730 when do_SUBST is called to replace the operand thereof, so we
731 perform this test on oldval instead, checking whether an
732 invalid replacement took place before we got here. */
733 gcc_assert (!(GET_CODE (oldval
) == SUBREG
734 && CONST_INT_P (SUBREG_REG (oldval
))));
735 gcc_assert (!(GET_CODE (oldval
) == ZERO_EXTEND
736 && CONST_INT_P (XEXP (oldval
, 0))));
740 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
742 buf
= XNEW (struct undo
);
744 buf
->kind
= UNDO_RTX
;
746 buf
->old_contents
.r
= oldval
;
749 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
752 #define SUBST(INTO, NEWVAL) do_SUBST (&(INTO), (NEWVAL))
754 /* Similar to SUBST, but NEWVAL is an int expression. Note that substitution
755 for the value of a HOST_WIDE_INT value (including CONST_INT) is
759 do_SUBST_INT (int *into
, int newval
)
764 if (oldval
== newval
)
768 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
770 buf
= XNEW (struct undo
);
772 buf
->kind
= UNDO_INT
;
774 buf
->old_contents
.i
= oldval
;
777 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
780 #define SUBST_INT(INTO, NEWVAL) do_SUBST_INT (&(INTO), (NEWVAL))
782 /* Similar to SUBST, but just substitute the mode. This is used when
783 changing the mode of a pseudo-register, so that any other
784 references to the entry in the regno_reg_rtx array will change as
788 do_SUBST_MODE (rtx
*into
, machine_mode newval
)
791 machine_mode oldval
= GET_MODE (*into
);
793 if (oldval
== newval
)
797 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
799 buf
= XNEW (struct undo
);
801 buf
->kind
= UNDO_MODE
;
803 buf
->old_contents
.m
= oldval
;
804 adjust_reg_mode (*into
, newval
);
806 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
809 #define SUBST_MODE(INTO, NEWVAL) do_SUBST_MODE (&(INTO), (NEWVAL))
811 /* Similar to SUBST, but NEWVAL is a LOG_LINKS expression. */
814 do_SUBST_LINK (struct insn_link
**into
, struct insn_link
*newval
)
817 struct insn_link
* oldval
= *into
;
819 if (oldval
== newval
)
823 buf
= undobuf
.frees
, undobuf
.frees
= buf
->next
;
825 buf
= XNEW (struct undo
);
827 buf
->kind
= UNDO_LINKS
;
829 buf
->old_contents
.l
= oldval
;
832 buf
->next
= undobuf
.undos
, undobuf
.undos
= buf
;
835 #define SUBST_LINK(oldval, newval) do_SUBST_LINK (&oldval, newval)
837 /* Subroutine of try_combine. Determine whether the replacement patterns
838 NEWPAT, NEWI2PAT and NEWOTHERPAT are cheaper according to insn_rtx_cost
839 than the original sequence I0, I1, I2, I3 and undobuf.other_insn. Note
840 that I0, I1 and/or NEWI2PAT may be NULL_RTX. Similarly, NEWOTHERPAT and
841 undobuf.other_insn may also both be NULL_RTX. Return false if the cost
842 of all the instructions can be estimated and the replacements are more
843 expensive than the original sequence. */
846 combine_validate_cost (rtx_insn
*i0
, rtx_insn
*i1
, rtx_insn
*i2
, rtx_insn
*i3
,
847 rtx newpat
, rtx newi2pat
, rtx newotherpat
)
849 int i0_cost
, i1_cost
, i2_cost
, i3_cost
;
850 int new_i2_cost
, new_i3_cost
;
851 int old_cost
, new_cost
;
853 /* Lookup the original insn_rtx_costs. */
854 i2_cost
= INSN_COST (i2
);
855 i3_cost
= INSN_COST (i3
);
859 i1_cost
= INSN_COST (i1
);
862 i0_cost
= INSN_COST (i0
);
863 old_cost
= (i0_cost
> 0 && i1_cost
> 0 && i2_cost
> 0 && i3_cost
> 0
864 ? i0_cost
+ i1_cost
+ i2_cost
+ i3_cost
: 0);
868 old_cost
= (i1_cost
> 0 && i2_cost
> 0 && i3_cost
> 0
869 ? i1_cost
+ i2_cost
+ i3_cost
: 0);
875 old_cost
= (i2_cost
> 0 && i3_cost
> 0) ? i2_cost
+ i3_cost
: 0;
876 i1_cost
= i0_cost
= 0;
879 /* If we have split a PARALLEL I2 to I1,I2, we have counted its cost twice;
881 if (old_cost
&& i1
&& INSN_UID (i1
) == INSN_UID (i2
))
885 /* Calculate the replacement insn_rtx_costs. */
886 new_i3_cost
= insn_rtx_cost (newpat
, optimize_this_for_speed_p
);
889 new_i2_cost
= insn_rtx_cost (newi2pat
, optimize_this_for_speed_p
);
890 new_cost
= (new_i2_cost
> 0 && new_i3_cost
> 0)
891 ? new_i2_cost
+ new_i3_cost
: 0;
895 new_cost
= new_i3_cost
;
899 if (undobuf
.other_insn
)
901 int old_other_cost
, new_other_cost
;
903 old_other_cost
= INSN_COST (undobuf
.other_insn
);
904 new_other_cost
= insn_rtx_cost (newotherpat
, optimize_this_for_speed_p
);
905 if (old_other_cost
> 0 && new_other_cost
> 0)
907 old_cost
+= old_other_cost
;
908 new_cost
+= new_other_cost
;
914 /* Disallow this combination if both new_cost and old_cost are greater than
915 zero, and new_cost is greater than old cost. */
916 int reject
= old_cost
> 0 && new_cost
> old_cost
;
920 fprintf (dump_file
, "%s combination of insns ",
921 reject
? "rejecting" : "allowing");
923 fprintf (dump_file
, "%d, ", INSN_UID (i0
));
924 if (i1
&& INSN_UID (i1
) != INSN_UID (i2
))
925 fprintf (dump_file
, "%d, ", INSN_UID (i1
));
926 fprintf (dump_file
, "%d and %d\n", INSN_UID (i2
), INSN_UID (i3
));
928 fprintf (dump_file
, "original costs ");
930 fprintf (dump_file
, "%d + ", i0_cost
);
931 if (i1
&& INSN_UID (i1
) != INSN_UID (i2
))
932 fprintf (dump_file
, "%d + ", i1_cost
);
933 fprintf (dump_file
, "%d + %d = %d\n", i2_cost
, i3_cost
, old_cost
);
936 fprintf (dump_file
, "replacement costs %d + %d = %d\n",
937 new_i2_cost
, new_i3_cost
, new_cost
);
939 fprintf (dump_file
, "replacement cost %d\n", new_cost
);
945 /* Update the uid_insn_cost array with the replacement costs. */
946 INSN_COST (i2
) = new_i2_cost
;
947 INSN_COST (i3
) = new_i3_cost
;
959 /* Delete any insns that copy a register to itself. */
962 delete_noop_moves (void)
964 rtx_insn
*insn
, *next
;
967 FOR_EACH_BB_FN (bb
, cfun
)
969 for (insn
= BB_HEAD (bb
); insn
!= NEXT_INSN (BB_END (bb
)); insn
= next
)
971 next
= NEXT_INSN (insn
);
972 if (INSN_P (insn
) && noop_move_p (insn
))
975 fprintf (dump_file
, "deleting noop move %d\n", INSN_UID (insn
));
977 delete_insn_and_edges (insn
);
984 /* Return false if we do not want to (or cannot) combine DEF. */
986 can_combine_def_p (df_ref def
)
988 /* Do not consider if it is pre/post modification in MEM. */
989 if (DF_REF_FLAGS (def
) & DF_REF_PRE_POST_MODIFY
)
992 unsigned int regno
= DF_REF_REGNO (def
);
994 /* Do not combine frame pointer adjustments. */
995 if ((regno
== FRAME_POINTER_REGNUM
996 && (!reload_completed
|| frame_pointer_needed
))
997 || (!HARD_FRAME_POINTER_IS_FRAME_POINTER
998 && regno
== HARD_FRAME_POINTER_REGNUM
999 && (!reload_completed
|| frame_pointer_needed
))
1000 || (FRAME_POINTER_REGNUM
!= ARG_POINTER_REGNUM
1001 && regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
]))
1007 /* Return false if we do not want to (or cannot) combine USE. */
1009 can_combine_use_p (df_ref use
)
1011 /* Do not consider the usage of the stack pointer by function call. */
1012 if (DF_REF_FLAGS (use
) & DF_REF_CALL_STACK_USAGE
)
1018 /* Fill in log links field for all insns. */
1021 create_log_links (void)
1024 rtx_insn
**next_use
;
1028 next_use
= XCNEWVEC (rtx_insn
*, max_reg_num ());
1030 /* Pass through each block from the end, recording the uses of each
1031 register and establishing log links when def is encountered.
1032 Note that we do not clear next_use array in order to save time,
1033 so we have to test whether the use is in the same basic block as def.
1035 There are a few cases below when we do not consider the definition or
1036 usage -- these are taken from original flow.c did. Don't ask me why it is
1037 done this way; I don't know and if it works, I don't want to know. */
1039 FOR_EACH_BB_FN (bb
, cfun
)
1041 FOR_BB_INSNS_REVERSE (bb
, insn
)
1043 if (!NONDEBUG_INSN_P (insn
))
1046 /* Log links are created only once. */
1047 gcc_assert (!LOG_LINKS (insn
));
1049 FOR_EACH_INSN_DEF (def
, insn
)
1051 unsigned int regno
= DF_REF_REGNO (def
);
1054 if (!next_use
[regno
])
1057 if (!can_combine_def_p (def
))
1060 use_insn
= next_use
[regno
];
1061 next_use
[regno
] = NULL
;
1063 if (BLOCK_FOR_INSN (use_insn
) != bb
)
1068 We don't build a LOG_LINK for hard registers contained
1069 in ASM_OPERANDs. If these registers get replaced,
1070 we might wind up changing the semantics of the insn,
1071 even if reload can make what appear to be valid
1072 assignments later. */
1073 if (regno
< FIRST_PSEUDO_REGISTER
1074 && asm_noperands (PATTERN (use_insn
)) >= 0)
1077 /* Don't add duplicate links between instructions. */
1078 struct insn_link
*links
;
1079 FOR_EACH_LOG_LINK (links
, use_insn
)
1080 if (insn
== links
->insn
&& regno
== links
->regno
)
1084 LOG_LINKS (use_insn
)
1085 = alloc_insn_link (insn
, regno
, LOG_LINKS (use_insn
));
1088 FOR_EACH_INSN_USE (use
, insn
)
1089 if (can_combine_use_p (use
))
1090 next_use
[DF_REF_REGNO (use
)] = insn
;
1097 /* Walk the LOG_LINKS of insn B to see if we find a reference to A. Return
1098 true if we found a LOG_LINK that proves that A feeds B. This only works
1099 if there are no instructions between A and B which could have a link
1100 depending on A, since in that case we would not record a link for B.
1101 We also check the implicit dependency created by a cc0 setter/user
1105 insn_a_feeds_b (rtx_insn
*a
, rtx_insn
*b
)
1107 struct insn_link
*links
;
1108 FOR_EACH_LOG_LINK (links
, b
)
1109 if (links
->insn
== a
)
1111 if (HAVE_cc0
&& sets_cc0_p (a
))
1116 /* Main entry point for combiner. F is the first insn of the function.
1117 NREGS is the first unused pseudo-reg number.
1119 Return nonzero if the combiner has turned an indirect jump
1120 instruction into a direct jump. */
1122 combine_instructions (rtx_insn
*f
, unsigned int nregs
)
1124 rtx_insn
*insn
, *next
;
1126 struct insn_link
*links
, *nextlinks
;
1128 basic_block last_bb
;
1130 int new_direct_jump_p
= 0;
1132 for (first
= f
; first
&& !INSN_P (first
); )
1133 first
= NEXT_INSN (first
);
1137 combine_attempts
= 0;
1140 combine_successes
= 0;
1142 rtl_hooks
= combine_rtl_hooks
;
1144 reg_stat
.safe_grow_cleared (nregs
);
1146 init_recog_no_volatile ();
1148 /* Allocate array for insn info. */
1149 max_uid_known
= get_max_uid ();
1150 uid_log_links
= XCNEWVEC (struct insn_link
*, max_uid_known
+ 1);
1151 uid_insn_cost
= XCNEWVEC (int, max_uid_known
+ 1);
1152 gcc_obstack_init (&insn_link_obstack
);
1154 nonzero_bits_mode
= mode_for_size (HOST_BITS_PER_WIDE_INT
, MODE_INT
, 0);
1156 /* Don't use reg_stat[].nonzero_bits when computing it. This can cause
1157 problems when, for example, we have j <<= 1 in a loop. */
1159 nonzero_sign_valid
= 0;
1160 label_tick
= label_tick_ebb_start
= 1;
1162 /* Scan all SETs and see if we can deduce anything about what
1163 bits are known to be zero for some registers and how many copies
1164 of the sign bit are known to exist for those registers.
1166 Also set any known values so that we can use it while searching
1167 for what bits are known to be set. */
1169 setup_incoming_promotions (first
);
1170 /* Allow the entry block and the first block to fall into the same EBB.
1171 Conceptually the incoming promotions are assigned to the entry block. */
1172 last_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
1174 create_log_links ();
1175 FOR_EACH_BB_FN (this_basic_block
, cfun
)
1177 optimize_this_for_speed_p
= optimize_bb_for_speed_p (this_basic_block
);
1182 if (!single_pred_p (this_basic_block
)
1183 || single_pred (this_basic_block
) != last_bb
)
1184 label_tick_ebb_start
= label_tick
;
1185 last_bb
= this_basic_block
;
1187 FOR_BB_INSNS (this_basic_block
, insn
)
1188 if (INSN_P (insn
) && BLOCK_FOR_INSN (insn
))
1192 subst_low_luid
= DF_INSN_LUID (insn
);
1195 note_stores (PATTERN (insn
), set_nonzero_bits_and_sign_copies
,
1197 record_dead_and_set_regs (insn
);
1200 for (links
= REG_NOTES (insn
); links
; links
= XEXP (links
, 1))
1201 if (REG_NOTE_KIND (links
) == REG_INC
)
1202 set_nonzero_bits_and_sign_copies (XEXP (links
, 0), NULL_RTX
,
1205 /* Record the current insn_rtx_cost of this instruction. */
1206 if (NONJUMP_INSN_P (insn
))
1207 INSN_COST (insn
) = insn_rtx_cost (PATTERN (insn
),
1208 optimize_this_for_speed_p
);
1210 fprintf (dump_file
, "insn_cost %d: %d\n",
1211 INSN_UID (insn
), INSN_COST (insn
));
1215 nonzero_sign_valid
= 1;
1217 /* Now scan all the insns in forward order. */
1218 label_tick
= label_tick_ebb_start
= 1;
1220 setup_incoming_promotions (first
);
1221 last_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
1222 int max_combine
= PARAM_VALUE (PARAM_MAX_COMBINE_INSNS
);
1224 FOR_EACH_BB_FN (this_basic_block
, cfun
)
1226 rtx_insn
*last_combined_insn
= NULL
;
1227 optimize_this_for_speed_p
= optimize_bb_for_speed_p (this_basic_block
);
1232 if (!single_pred_p (this_basic_block
)
1233 || single_pred (this_basic_block
) != last_bb
)
1234 label_tick_ebb_start
= label_tick
;
1235 last_bb
= this_basic_block
;
1237 rtl_profile_for_bb (this_basic_block
);
1238 for (insn
= BB_HEAD (this_basic_block
);
1239 insn
!= NEXT_INSN (BB_END (this_basic_block
));
1240 insn
= next
? next
: NEXT_INSN (insn
))
1243 if (!NONDEBUG_INSN_P (insn
))
1246 while (last_combined_insn
1247 && last_combined_insn
->deleted ())
1248 last_combined_insn
= PREV_INSN (last_combined_insn
);
1249 if (last_combined_insn
== NULL_RTX
1250 || BARRIER_P (last_combined_insn
)
1251 || BLOCK_FOR_INSN (last_combined_insn
) != this_basic_block
1252 || DF_INSN_LUID (last_combined_insn
) <= DF_INSN_LUID (insn
))
1253 last_combined_insn
= insn
;
1255 /* See if we know about function return values before this
1256 insn based upon SUBREG flags. */
1257 check_promoted_subreg (insn
, PATTERN (insn
));
1259 /* See if we can find hardregs and subreg of pseudos in
1260 narrower modes. This could help turning TRUNCATEs
1262 note_uses (&PATTERN (insn
), record_truncated_values
, NULL
);
1264 /* Try this insn with each insn it links back to. */
1266 FOR_EACH_LOG_LINK (links
, insn
)
1267 if ((next
= try_combine (insn
, links
->insn
, NULL
,
1268 NULL
, &new_direct_jump_p
,
1269 last_combined_insn
)) != 0)
1271 statistics_counter_event (cfun
, "two-insn combine", 1);
1275 /* Try each sequence of three linked insns ending with this one. */
1277 if (max_combine
>= 3)
1278 FOR_EACH_LOG_LINK (links
, insn
)
1280 rtx_insn
*link
= links
->insn
;
1282 /* If the linked insn has been replaced by a note, then there
1283 is no point in pursuing this chain any further. */
1287 FOR_EACH_LOG_LINK (nextlinks
, link
)
1288 if ((next
= try_combine (insn
, link
, nextlinks
->insn
,
1289 NULL
, &new_direct_jump_p
,
1290 last_combined_insn
)) != 0)
1292 statistics_counter_event (cfun
, "three-insn combine", 1);
1297 /* Try to combine a jump insn that uses CC0
1298 with a preceding insn that sets CC0, and maybe with its
1299 logical predecessor as well.
1300 This is how we make decrement-and-branch insns.
1301 We need this special code because data flow connections
1302 via CC0 do not get entered in LOG_LINKS. */
1306 && (prev
= prev_nonnote_insn (insn
)) != 0
1307 && NONJUMP_INSN_P (prev
)
1308 && sets_cc0_p (PATTERN (prev
)))
1310 if ((next
= try_combine (insn
, prev
, NULL
, NULL
,
1312 last_combined_insn
)) != 0)
1315 FOR_EACH_LOG_LINK (nextlinks
, prev
)
1316 if ((next
= try_combine (insn
, prev
, nextlinks
->insn
,
1317 NULL
, &new_direct_jump_p
,
1318 last_combined_insn
)) != 0)
1322 /* Do the same for an insn that explicitly references CC0. */
1323 if (HAVE_cc0
&& NONJUMP_INSN_P (insn
)
1324 && (prev
= prev_nonnote_insn (insn
)) != 0
1325 && NONJUMP_INSN_P (prev
)
1326 && sets_cc0_p (PATTERN (prev
))
1327 && GET_CODE (PATTERN (insn
)) == SET
1328 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (insn
))))
1330 if ((next
= try_combine (insn
, prev
, NULL
, NULL
,
1332 last_combined_insn
)) != 0)
1335 FOR_EACH_LOG_LINK (nextlinks
, prev
)
1336 if ((next
= try_combine (insn
, prev
, nextlinks
->insn
,
1337 NULL
, &new_direct_jump_p
,
1338 last_combined_insn
)) != 0)
1342 /* Finally, see if any of the insns that this insn links to
1343 explicitly references CC0. If so, try this insn, that insn,
1344 and its predecessor if it sets CC0. */
1347 FOR_EACH_LOG_LINK (links
, insn
)
1348 if (NONJUMP_INSN_P (links
->insn
)
1349 && GET_CODE (PATTERN (links
->insn
)) == SET
1350 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (links
->insn
)))
1351 && (prev
= prev_nonnote_insn (links
->insn
)) != 0
1352 && NONJUMP_INSN_P (prev
)
1353 && sets_cc0_p (PATTERN (prev
))
1354 && (next
= try_combine (insn
, links
->insn
,
1355 prev
, NULL
, &new_direct_jump_p
,
1356 last_combined_insn
)) != 0)
1360 /* Try combining an insn with two different insns whose results it
1362 if (max_combine
>= 3)
1363 FOR_EACH_LOG_LINK (links
, insn
)
1364 for (nextlinks
= links
->next
; nextlinks
;
1365 nextlinks
= nextlinks
->next
)
1366 if ((next
= try_combine (insn
, links
->insn
,
1367 nextlinks
->insn
, NULL
,
1369 last_combined_insn
)) != 0)
1372 statistics_counter_event (cfun
, "three-insn combine", 1);
1376 /* Try four-instruction combinations. */
1377 if (max_combine
>= 4)
1378 FOR_EACH_LOG_LINK (links
, insn
)
1380 struct insn_link
*next1
;
1381 rtx_insn
*link
= links
->insn
;
1383 /* If the linked insn has been replaced by a note, then there
1384 is no point in pursuing this chain any further. */
1388 FOR_EACH_LOG_LINK (next1
, link
)
1390 rtx_insn
*link1
= next1
->insn
;
1393 /* I0 -> I1 -> I2 -> I3. */
1394 FOR_EACH_LOG_LINK (nextlinks
, link1
)
1395 if ((next
= try_combine (insn
, link
, link1
,
1398 last_combined_insn
)) != 0)
1400 statistics_counter_event (cfun
, "four-insn combine", 1);
1403 /* I0, I1 -> I2, I2 -> I3. */
1404 for (nextlinks
= next1
->next
; nextlinks
;
1405 nextlinks
= nextlinks
->next
)
1406 if ((next
= try_combine (insn
, link
, link1
,
1409 last_combined_insn
)) != 0)
1411 statistics_counter_event (cfun
, "four-insn combine", 1);
1416 for (next1
= links
->next
; next1
; next1
= next1
->next
)
1418 rtx_insn
*link1
= next1
->insn
;
1421 /* I0 -> I2; I1, I2 -> I3. */
1422 FOR_EACH_LOG_LINK (nextlinks
, link
)
1423 if ((next
= try_combine (insn
, link
, link1
,
1426 last_combined_insn
)) != 0)
1428 statistics_counter_event (cfun
, "four-insn combine", 1);
1431 /* I0 -> I1; I1, I2 -> I3. */
1432 FOR_EACH_LOG_LINK (nextlinks
, link1
)
1433 if ((next
= try_combine (insn
, link
, link1
,
1436 last_combined_insn
)) != 0)
1438 statistics_counter_event (cfun
, "four-insn combine", 1);
1444 /* Try this insn with each REG_EQUAL note it links back to. */
1445 FOR_EACH_LOG_LINK (links
, insn
)
1448 rtx_insn
*temp
= links
->insn
;
1449 if ((set
= single_set (temp
)) != 0
1450 && (note
= find_reg_equal_equiv_note (temp
)) != 0
1451 && (note
= XEXP (note
, 0), GET_CODE (note
)) != EXPR_LIST
1452 /* Avoid using a register that may already been marked
1453 dead by an earlier instruction. */
1454 && ! unmentioned_reg_p (note
, SET_SRC (set
))
1455 && (GET_MODE (note
) == VOIDmode
1456 ? SCALAR_INT_MODE_P (GET_MODE (SET_DEST (set
)))
1457 : (GET_MODE (SET_DEST (set
)) == GET_MODE (note
)
1458 && (GET_CODE (SET_DEST (set
)) != ZERO_EXTRACT
1459 || (GET_MODE (XEXP (SET_DEST (set
), 0))
1460 == GET_MODE (note
))))))
1462 /* Temporarily replace the set's source with the
1463 contents of the REG_EQUAL note. The insn will
1464 be deleted or recognized by try_combine. */
1465 rtx orig_src
= SET_SRC (set
);
1466 rtx orig_dest
= SET_DEST (set
);
1467 if (GET_CODE (SET_DEST (set
)) == ZERO_EXTRACT
)
1468 SET_DEST (set
) = XEXP (SET_DEST (set
), 0);
1469 SET_SRC (set
) = note
;
1471 i2mod_old_rhs
= copy_rtx (orig_src
);
1472 i2mod_new_rhs
= copy_rtx (note
);
1473 next
= try_combine (insn
, i2mod
, NULL
, NULL
,
1475 last_combined_insn
);
1479 statistics_counter_event (cfun
, "insn-with-note combine", 1);
1482 SET_SRC (set
) = orig_src
;
1483 SET_DEST (set
) = orig_dest
;
1488 record_dead_and_set_regs (insn
);
1495 default_rtl_profile ();
1497 new_direct_jump_p
|= purge_all_dead_edges ();
1498 delete_noop_moves ();
1501 obstack_free (&insn_link_obstack
, NULL
);
1502 free (uid_log_links
);
1503 free (uid_insn_cost
);
1504 reg_stat
.release ();
1507 struct undo
*undo
, *next
;
1508 for (undo
= undobuf
.frees
; undo
; undo
= next
)
1516 total_attempts
+= combine_attempts
;
1517 total_merges
+= combine_merges
;
1518 total_extras
+= combine_extras
;
1519 total_successes
+= combine_successes
;
1521 nonzero_sign_valid
= 0;
1522 rtl_hooks
= general_rtl_hooks
;
1524 /* Make recognizer allow volatile MEMs again. */
1527 return new_direct_jump_p
;
1530 /* Wipe the last_xxx fields of reg_stat in preparation for another pass. */
1533 init_reg_last (void)
1538 FOR_EACH_VEC_ELT (reg_stat
, i
, p
)
1539 memset (p
, 0, offsetof (reg_stat_type
, sign_bit_copies
));
1542 /* Set up any promoted values for incoming argument registers. */
1545 setup_incoming_promotions (rtx_insn
*first
)
1548 bool strictly_local
= false;
1550 for (arg
= DECL_ARGUMENTS (current_function_decl
); arg
;
1551 arg
= DECL_CHAIN (arg
))
1553 rtx x
, reg
= DECL_INCOMING_RTL (arg
);
1555 machine_mode mode1
, mode2
, mode3
, mode4
;
1557 /* Only continue if the incoming argument is in a register. */
1561 /* Determine, if possible, whether all call sites of the current
1562 function lie within the current compilation unit. (This does
1563 take into account the exporting of a function via taking its
1564 address, and so forth.) */
1565 strictly_local
= cgraph_node::local_info (current_function_decl
)->local
;
1567 /* The mode and signedness of the argument before any promotions happen
1568 (equal to the mode of the pseudo holding it at that stage). */
1569 mode1
= TYPE_MODE (TREE_TYPE (arg
));
1570 uns1
= TYPE_UNSIGNED (TREE_TYPE (arg
));
1572 /* The mode and signedness of the argument after any source language and
1573 TARGET_PROMOTE_PROTOTYPES-driven promotions. */
1574 mode2
= TYPE_MODE (DECL_ARG_TYPE (arg
));
1575 uns3
= TYPE_UNSIGNED (DECL_ARG_TYPE (arg
));
1577 /* The mode and signedness of the argument as it is actually passed,
1578 see assign_parm_setup_reg in function.c. */
1579 mode3
= promote_function_mode (TREE_TYPE (arg
), mode1
, &uns3
,
1580 TREE_TYPE (cfun
->decl
), 0);
1582 /* The mode of the register in which the argument is being passed. */
1583 mode4
= GET_MODE (reg
);
1585 /* Eliminate sign extensions in the callee when:
1586 (a) A mode promotion has occurred; */
1589 /* (b) The mode of the register is the same as the mode of
1590 the argument as it is passed; */
1593 /* (c) There's no language level extension; */
1596 /* (c.1) All callers are from the current compilation unit. If that's
1597 the case we don't have to rely on an ABI, we only have to know
1598 what we're generating right now, and we know that we will do the
1599 mode1 to mode2 promotion with the given sign. */
1600 else if (!strictly_local
)
1602 /* (c.2) The combination of the two promotions is useful. This is
1603 true when the signs match, or if the first promotion is unsigned.
1604 In the later case, (sign_extend (zero_extend x)) is the same as
1605 (zero_extend (zero_extend x)), so make sure to force UNS3 true. */
1611 /* Record that the value was promoted from mode1 to mode3,
1612 so that any sign extension at the head of the current
1613 function may be eliminated. */
1614 x
= gen_rtx_CLOBBER (mode1
, const0_rtx
);
1615 x
= gen_rtx_fmt_e ((uns3
? ZERO_EXTEND
: SIGN_EXTEND
), mode3
, x
);
1616 record_value_for_reg (reg
, first
, x
);
1620 /* If MODE has a precision lower than PREC and SRC is a non-negative constant
1621 that would appear negative in MODE, sign-extend SRC for use in nonzero_bits
1622 because some machines (maybe most) will actually do the sign-extension and
1623 this is the conservative approach.
1625 ??? For 2.5, try to tighten up the MD files in this regard instead of this
1629 sign_extend_short_imm (rtx src
, machine_mode mode
, unsigned int prec
)
1631 if (GET_MODE_PRECISION (mode
) < prec
1632 && CONST_INT_P (src
)
1634 && val_signbit_known_set_p (mode
, INTVAL (src
)))
1635 src
= GEN_INT (INTVAL (src
) | ~GET_MODE_MASK (mode
));
1640 /* Update RSP for pseudo-register X from INSN's REG_EQUAL note (if one exists)
1644 update_rsp_from_reg_equal (reg_stat_type
*rsp
, rtx_insn
*insn
, const_rtx set
,
1647 rtx reg_equal_note
= insn
? find_reg_equal_equiv_note (insn
) : NULL_RTX
;
1648 unsigned HOST_WIDE_INT bits
= 0;
1649 rtx reg_equal
= NULL
, src
= SET_SRC (set
);
1650 unsigned int num
= 0;
1653 reg_equal
= XEXP (reg_equal_note
, 0);
1655 if (SHORT_IMMEDIATES_SIGN_EXTEND
)
1657 src
= sign_extend_short_imm (src
, GET_MODE (x
), BITS_PER_WORD
);
1659 reg_equal
= sign_extend_short_imm (reg_equal
, GET_MODE (x
), BITS_PER_WORD
);
1662 /* Don't call nonzero_bits if it cannot change anything. */
1663 if (rsp
->nonzero_bits
!= ~(unsigned HOST_WIDE_INT
) 0)
1665 bits
= nonzero_bits (src
, nonzero_bits_mode
);
1666 if (reg_equal
&& bits
)
1667 bits
&= nonzero_bits (reg_equal
, nonzero_bits_mode
);
1668 rsp
->nonzero_bits
|= bits
;
1671 /* Don't call num_sign_bit_copies if it cannot change anything. */
1672 if (rsp
->sign_bit_copies
!= 1)
1674 num
= num_sign_bit_copies (SET_SRC (set
), GET_MODE (x
));
1675 if (reg_equal
&& num
!= GET_MODE_PRECISION (GET_MODE (x
)))
1677 unsigned int numeq
= num_sign_bit_copies (reg_equal
, GET_MODE (x
));
1678 if (num
== 0 || numeq
> num
)
1681 if (rsp
->sign_bit_copies
== 0 || num
< rsp
->sign_bit_copies
)
1682 rsp
->sign_bit_copies
= num
;
1686 /* Called via note_stores. If X is a pseudo that is narrower than
1687 HOST_BITS_PER_WIDE_INT and is being set, record what bits are known zero.
1689 If we are setting only a portion of X and we can't figure out what
1690 portion, assume all bits will be used since we don't know what will
1693 Similarly, set how many bits of X are known to be copies of the sign bit
1694 at all locations in the function. This is the smallest number implied
1698 set_nonzero_bits_and_sign_copies (rtx x
, const_rtx set
, void *data
)
1700 rtx_insn
*insn
= (rtx_insn
*) data
;
1703 && REGNO (x
) >= FIRST_PSEUDO_REGISTER
1704 /* If this register is undefined at the start of the file, we can't
1705 say what its contents were. */
1706 && ! REGNO_REG_SET_P
1707 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
), REGNO (x
))
1708 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
)))
1710 reg_stat_type
*rsp
= ®_stat
[REGNO (x
)];
1712 if (set
== 0 || GET_CODE (set
) == CLOBBER
)
1714 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1715 rsp
->sign_bit_copies
= 1;
1719 /* If this register is being initialized using itself, and the
1720 register is uninitialized in this basic block, and there are
1721 no LOG_LINKS which set the register, then part of the
1722 register is uninitialized. In that case we can't assume
1723 anything about the number of nonzero bits.
1725 ??? We could do better if we checked this in
1726 reg_{nonzero_bits,num_sign_bit_copies}_for_combine. Then we
1727 could avoid making assumptions about the insn which initially
1728 sets the register, while still using the information in other
1729 insns. We would have to be careful to check every insn
1730 involved in the combination. */
1733 && reg_referenced_p (x
, PATTERN (insn
))
1734 && !REGNO_REG_SET_P (DF_LR_IN (BLOCK_FOR_INSN (insn
)),
1737 struct insn_link
*link
;
1739 FOR_EACH_LOG_LINK (link
, insn
)
1740 if (dead_or_set_p (link
->insn
, x
))
1744 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1745 rsp
->sign_bit_copies
= 1;
1750 /* If this is a complex assignment, see if we can convert it into a
1751 simple assignment. */
1752 set
= expand_field_assignment (set
);
1754 /* If this is a simple assignment, or we have a paradoxical SUBREG,
1755 set what we know about X. */
1757 if (SET_DEST (set
) == x
1758 || (paradoxical_subreg_p (SET_DEST (set
))
1759 && SUBREG_REG (SET_DEST (set
)) == x
))
1760 update_rsp_from_reg_equal (rsp
, insn
, set
, x
);
1763 rsp
->nonzero_bits
= GET_MODE_MASK (GET_MODE (x
));
1764 rsp
->sign_bit_copies
= 1;
1769 /* See if INSN can be combined into I3. PRED, PRED2, SUCC and SUCC2 are
1770 optionally insns that were previously combined into I3 or that will be
1771 combined into the merger of INSN and I3. The order is PRED, PRED2,
1772 INSN, SUCC, SUCC2, I3.
1774 Return 0 if the combination is not allowed for any reason.
1776 If the combination is allowed, *PDEST will be set to the single
1777 destination of INSN and *PSRC to the single source, and this function
1781 can_combine_p (rtx_insn
*insn
, rtx_insn
*i3
, rtx_insn
*pred ATTRIBUTE_UNUSED
,
1782 rtx_insn
*pred2 ATTRIBUTE_UNUSED
, rtx_insn
*succ
, rtx_insn
*succ2
,
1783 rtx
*pdest
, rtx
*psrc
)
1790 bool all_adjacent
= true;
1791 int (*is_volatile_p
) (const_rtx
);
1797 if (next_active_insn (succ2
) != i3
)
1798 all_adjacent
= false;
1799 if (next_active_insn (succ
) != succ2
)
1800 all_adjacent
= false;
1802 else if (next_active_insn (succ
) != i3
)
1803 all_adjacent
= false;
1804 if (next_active_insn (insn
) != succ
)
1805 all_adjacent
= false;
1807 else if (next_active_insn (insn
) != i3
)
1808 all_adjacent
= false;
1810 /* Can combine only if previous insn is a SET of a REG, a SUBREG or CC0.
1811 or a PARALLEL consisting of such a SET and CLOBBERs.
1813 If INSN has CLOBBER parallel parts, ignore them for our processing.
1814 By definition, these happen during the execution of the insn. When it
1815 is merged with another insn, all bets are off. If they are, in fact,
1816 needed and aren't also supplied in I3, they may be added by
1817 recog_for_combine. Otherwise, it won't match.
1819 We can also ignore a SET whose SET_DEST is mentioned in a REG_UNUSED
1822 Get the source and destination of INSN. If more than one, can't
1825 if (GET_CODE (PATTERN (insn
)) == SET
)
1826 set
= PATTERN (insn
);
1827 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
1828 && GET_CODE (XVECEXP (PATTERN (insn
), 0, 0)) == SET
)
1830 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
1832 rtx elt
= XVECEXP (PATTERN (insn
), 0, i
);
1834 switch (GET_CODE (elt
))
1836 /* This is important to combine floating point insns
1837 for the SH4 port. */
1839 /* Combining an isolated USE doesn't make sense.
1840 We depend here on combinable_i3pat to reject them. */
1841 /* The code below this loop only verifies that the inputs of
1842 the SET in INSN do not change. We call reg_set_between_p
1843 to verify that the REG in the USE does not change between
1845 If the USE in INSN was for a pseudo register, the matching
1846 insn pattern will likely match any register; combining this
1847 with any other USE would only be safe if we knew that the
1848 used registers have identical values, or if there was
1849 something to tell them apart, e.g. different modes. For
1850 now, we forgo such complicated tests and simply disallow
1851 combining of USES of pseudo registers with any other USE. */
1852 if (REG_P (XEXP (elt
, 0))
1853 && GET_CODE (PATTERN (i3
)) == PARALLEL
)
1855 rtx i3pat
= PATTERN (i3
);
1856 int i
= XVECLEN (i3pat
, 0) - 1;
1857 unsigned int regno
= REGNO (XEXP (elt
, 0));
1861 rtx i3elt
= XVECEXP (i3pat
, 0, i
);
1863 if (GET_CODE (i3elt
) == USE
1864 && REG_P (XEXP (i3elt
, 0))
1865 && (REGNO (XEXP (i3elt
, 0)) == regno
1866 ? reg_set_between_p (XEXP (elt
, 0),
1867 PREV_INSN (insn
), i3
)
1868 : regno
>= FIRST_PSEUDO_REGISTER
))
1875 /* We can ignore CLOBBERs. */
1880 /* Ignore SETs whose result isn't used but not those that
1881 have side-effects. */
1882 if (find_reg_note (insn
, REG_UNUSED
, SET_DEST (elt
))
1883 && insn_nothrow_p (insn
)
1884 && !side_effects_p (elt
))
1887 /* If we have already found a SET, this is a second one and
1888 so we cannot combine with this insn. */
1896 /* Anything else means we can't combine. */
1902 /* If SET_SRC is an ASM_OPERANDS we can't throw away these CLOBBERs,
1903 so don't do anything with it. */
1904 || GET_CODE (SET_SRC (set
)) == ASM_OPERANDS
)
1913 /* The simplification in expand_field_assignment may call back to
1914 get_last_value, so set safe guard here. */
1915 subst_low_luid
= DF_INSN_LUID (insn
);
1917 set
= expand_field_assignment (set
);
1918 src
= SET_SRC (set
), dest
= SET_DEST (set
);
1920 /* Do not eliminate user-specified register if it is in an
1921 asm input because we may break the register asm usage defined
1922 in GCC manual if allow to do so.
1923 Be aware that this may cover more cases than we expect but this
1924 should be harmless. */
1925 if (REG_P (dest
) && REG_USERVAR_P (dest
) && HARD_REGISTER_P (dest
)
1926 && extract_asm_operands (PATTERN (i3
)))
1929 /* Don't eliminate a store in the stack pointer. */
1930 if (dest
== stack_pointer_rtx
1931 /* Don't combine with an insn that sets a register to itself if it has
1932 a REG_EQUAL note. This may be part of a LIBCALL sequence. */
1933 || (rtx_equal_p (src
, dest
) && find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1934 /* Can't merge an ASM_OPERANDS. */
1935 || GET_CODE (src
) == ASM_OPERANDS
1936 /* Can't merge a function call. */
1937 || GET_CODE (src
) == CALL
1938 /* Don't eliminate a function call argument. */
1940 && (find_reg_fusage (i3
, USE
, dest
)
1942 && REGNO (dest
) < FIRST_PSEUDO_REGISTER
1943 && global_regs
[REGNO (dest
)])))
1944 /* Don't substitute into an incremented register. */
1945 || FIND_REG_INC_NOTE (i3
, dest
)
1946 || (succ
&& FIND_REG_INC_NOTE (succ
, dest
))
1947 || (succ2
&& FIND_REG_INC_NOTE (succ2
, dest
))
1948 /* Don't substitute into a non-local goto, this confuses CFG. */
1949 || (JUMP_P (i3
) && find_reg_note (i3
, REG_NON_LOCAL_GOTO
, NULL_RTX
))
1950 /* Make sure that DEST is not used after SUCC but before I3. */
1953 && (reg_used_between_p (dest
, succ2
, i3
)
1954 || reg_used_between_p (dest
, succ
, succ2
)))
1955 || (!succ2
&& succ
&& reg_used_between_p (dest
, succ
, i3
))))
1956 /* Make sure that the value that is to be substituted for the register
1957 does not use any registers whose values alter in between. However,
1958 If the insns are adjacent, a use can't cross a set even though we
1959 think it might (this can happen for a sequence of insns each setting
1960 the same destination; last_set of that register might point to
1961 a NOTE). If INSN has a REG_EQUIV note, the register is always
1962 equivalent to the memory so the substitution is valid even if there
1963 are intervening stores. Also, don't move a volatile asm or
1964 UNSPEC_VOLATILE across any other insns. */
1967 || ! find_reg_note (insn
, REG_EQUIV
, src
))
1968 && use_crosses_set_p (src
, DF_INSN_LUID (insn
)))
1969 || (GET_CODE (src
) == ASM_OPERANDS
&& MEM_VOLATILE_P (src
))
1970 || GET_CODE (src
) == UNSPEC_VOLATILE
))
1971 /* Don't combine across a CALL_INSN, because that would possibly
1972 change whether the life span of some REGs crosses calls or not,
1973 and it is a pain to update that information.
1974 Exception: if source is a constant, moving it later can't hurt.
1975 Accept that as a special case. */
1976 || (DF_INSN_LUID (insn
) < last_call_luid
&& ! CONSTANT_P (src
)))
1979 /* DEST must either be a REG or CC0. */
1982 /* If register alignment is being enforced for multi-word items in all
1983 cases except for parameters, it is possible to have a register copy
1984 insn referencing a hard register that is not allowed to contain the
1985 mode being copied and which would not be valid as an operand of most
1986 insns. Eliminate this problem by not combining with such an insn.
1988 Also, on some machines we don't want to extend the life of a hard
1992 && ((REGNO (dest
) < FIRST_PSEUDO_REGISTER
1993 && ! HARD_REGNO_MODE_OK (REGNO (dest
), GET_MODE (dest
)))
1994 /* Don't extend the life of a hard register unless it is
1995 user variable (if we have few registers) or it can't
1996 fit into the desired register (meaning something special
1998 Also avoid substituting a return register into I3, because
1999 reload can't handle a conflict with constraints of other
2001 || (REGNO (src
) < FIRST_PSEUDO_REGISTER
2002 && ! HARD_REGNO_MODE_OK (REGNO (src
), GET_MODE (src
)))))
2005 else if (GET_CODE (dest
) != CC0
)
2009 if (GET_CODE (PATTERN (i3
)) == PARALLEL
)
2010 for (i
= XVECLEN (PATTERN (i3
), 0) - 1; i
>= 0; i
--)
2011 if (GET_CODE (XVECEXP (PATTERN (i3
), 0, i
)) == CLOBBER
)
2013 rtx reg
= XEXP (XVECEXP (PATTERN (i3
), 0, i
), 0);
2015 /* If the clobber represents an earlyclobber operand, we must not
2016 substitute an expression containing the clobbered register.
2017 As we do not analyze the constraint strings here, we have to
2018 make the conservative assumption. However, if the register is
2019 a fixed hard reg, the clobber cannot represent any operand;
2020 we leave it up to the machine description to either accept or
2021 reject use-and-clobber patterns. */
2023 || REGNO (reg
) >= FIRST_PSEUDO_REGISTER
2024 || !fixed_regs
[REGNO (reg
)])
2025 if (reg_overlap_mentioned_p (reg
, src
))
2029 /* If INSN contains anything volatile, or is an `asm' (whether volatile
2030 or not), reject, unless nothing volatile comes between it and I3 */
2032 if (GET_CODE (src
) == ASM_OPERANDS
|| volatile_refs_p (src
))
2034 /* Make sure neither succ nor succ2 contains a volatile reference. */
2035 if (succ2
!= 0 && volatile_refs_p (PATTERN (succ2
)))
2037 if (succ
!= 0 && volatile_refs_p (PATTERN (succ
)))
2039 /* We'll check insns between INSN and I3 below. */
2042 /* If INSN is an asm, and DEST is a hard register, reject, since it has
2043 to be an explicit register variable, and was chosen for a reason. */
2045 if (GET_CODE (src
) == ASM_OPERANDS
2046 && REG_P (dest
) && REGNO (dest
) < FIRST_PSEUDO_REGISTER
)
2049 /* If INSN contains volatile references (specifically volatile MEMs),
2050 we cannot combine across any other volatile references.
2051 Even if INSN doesn't contain volatile references, any intervening
2052 volatile insn might affect machine state. */
2054 is_volatile_p
= volatile_refs_p (PATTERN (insn
))
2058 for (p
= NEXT_INSN (insn
); p
!= i3
; p
= NEXT_INSN (p
))
2059 if (INSN_P (p
) && p
!= succ
&& p
!= succ2
&& is_volatile_p (PATTERN (p
)))
2062 /* If INSN contains an autoincrement or autodecrement, make sure that
2063 register is not used between there and I3, and not already used in
2064 I3 either. Neither must it be used in PRED or SUCC, if they exist.
2065 Also insist that I3 not be a jump; if it were one
2066 and the incremented register were spilled, we would lose. */
2069 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2070 if (REG_NOTE_KIND (link
) == REG_INC
2072 || reg_used_between_p (XEXP (link
, 0), insn
, i3
)
2073 || (pred
!= NULL_RTX
2074 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (pred
)))
2075 || (pred2
!= NULL_RTX
2076 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (pred2
)))
2077 || (succ
!= NULL_RTX
2078 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (succ
)))
2079 || (succ2
!= NULL_RTX
2080 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (succ2
)))
2081 || reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i3
))))
2084 /* Don't combine an insn that follows a CC0-setting insn.
2085 An insn that uses CC0 must not be separated from the one that sets it.
2086 We do, however, allow I2 to follow a CC0-setting insn if that insn
2087 is passed as I1; in that case it will be deleted also.
2088 We also allow combining in this case if all the insns are adjacent
2089 because that would leave the two CC0 insns adjacent as well.
2090 It would be more logical to test whether CC0 occurs inside I1 or I2,
2091 but that would be much slower, and this ought to be equivalent. */
2095 p
= prev_nonnote_insn (insn
);
2096 if (p
&& p
!= pred
&& NONJUMP_INSN_P (p
) && sets_cc0_p (PATTERN (p
))
2101 /* If we get here, we have passed all the tests and the combination is
2110 /* LOC is the location within I3 that contains its pattern or the component
2111 of a PARALLEL of the pattern. We validate that it is valid for combining.
2113 One problem is if I3 modifies its output, as opposed to replacing it
2114 entirely, we can't allow the output to contain I2DEST, I1DEST or I0DEST as
2115 doing so would produce an insn that is not equivalent to the original insns.
2119 (set (reg:DI 101) (reg:DI 100))
2120 (set (subreg:SI (reg:DI 101) 0) <foo>)
2122 This is NOT equivalent to:
2124 (parallel [(set (subreg:SI (reg:DI 100) 0) <foo>)
2125 (set (reg:DI 101) (reg:DI 100))])
2127 Not only does this modify 100 (in which case it might still be valid
2128 if 100 were dead in I2), it sets 101 to the ORIGINAL value of 100.
2130 We can also run into a problem if I2 sets a register that I1
2131 uses and I1 gets directly substituted into I3 (not via I2). In that
2132 case, we would be getting the wrong value of I2DEST into I3, so we
2133 must reject the combination. This case occurs when I2 and I1 both
2134 feed into I3, rather than when I1 feeds into I2, which feeds into I3.
2135 If I1_NOT_IN_SRC is nonzero, it means that finding I1 in the source
2136 of a SET must prevent combination from occurring. The same situation
2137 can occur for I0, in which case I0_NOT_IN_SRC is set.
2139 Before doing the above check, we first try to expand a field assignment
2140 into a set of logical operations.
2142 If PI3_DEST_KILLED is nonzero, it is a pointer to a location in which
2143 we place a register that is both set and used within I3. If more than one
2144 such register is detected, we fail.
2146 Return 1 if the combination is valid, zero otherwise. */
2149 combinable_i3pat (rtx_insn
*i3
, rtx
*loc
, rtx i2dest
, rtx i1dest
, rtx i0dest
,
2150 int i1_not_in_src
, int i0_not_in_src
, rtx
*pi3dest_killed
)
2154 if (GET_CODE (x
) == SET
)
2157 rtx dest
= SET_DEST (set
);
2158 rtx src
= SET_SRC (set
);
2159 rtx inner_dest
= dest
;
2162 while (GET_CODE (inner_dest
) == STRICT_LOW_PART
2163 || GET_CODE (inner_dest
) == SUBREG
2164 || GET_CODE (inner_dest
) == ZERO_EXTRACT
)
2165 inner_dest
= XEXP (inner_dest
, 0);
2167 /* Check for the case where I3 modifies its output, as discussed
2168 above. We don't want to prevent pseudos from being combined
2169 into the address of a MEM, so only prevent the combination if
2170 i1 or i2 set the same MEM. */
2171 if ((inner_dest
!= dest
&&
2172 (!MEM_P (inner_dest
)
2173 || rtx_equal_p (i2dest
, inner_dest
)
2174 || (i1dest
&& rtx_equal_p (i1dest
, inner_dest
))
2175 || (i0dest
&& rtx_equal_p (i0dest
, inner_dest
)))
2176 && (reg_overlap_mentioned_p (i2dest
, inner_dest
)
2177 || (i1dest
&& reg_overlap_mentioned_p (i1dest
, inner_dest
))
2178 || (i0dest
&& reg_overlap_mentioned_p (i0dest
, inner_dest
))))
2180 /* This is the same test done in can_combine_p except we can't test
2181 all_adjacent; we don't have to, since this instruction will stay
2182 in place, thus we are not considering increasing the lifetime of
2185 Also, if this insn sets a function argument, combining it with
2186 something that might need a spill could clobber a previous
2187 function argument; the all_adjacent test in can_combine_p also
2188 checks this; here, we do a more specific test for this case. */
2190 || (REG_P (inner_dest
)
2191 && REGNO (inner_dest
) < FIRST_PSEUDO_REGISTER
2192 && (! HARD_REGNO_MODE_OK (REGNO (inner_dest
),
2193 GET_MODE (inner_dest
))))
2194 || (i1_not_in_src
&& reg_overlap_mentioned_p (i1dest
, src
))
2195 || (i0_not_in_src
&& reg_overlap_mentioned_p (i0dest
, src
)))
2198 /* If DEST is used in I3, it is being killed in this insn, so
2199 record that for later. We have to consider paradoxical
2200 subregs here, since they kill the whole register, but we
2201 ignore partial subregs, STRICT_LOW_PART, etc.
2202 Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the
2203 STACK_POINTER_REGNUM, since these are always considered to be
2204 live. Similarly for ARG_POINTER_REGNUM if it is fixed. */
2206 if (GET_CODE (subdest
) == SUBREG
2207 && (GET_MODE_SIZE (GET_MODE (subdest
))
2208 >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (subdest
)))))
2209 subdest
= SUBREG_REG (subdest
);
2212 && reg_referenced_p (subdest
, PATTERN (i3
))
2213 && REGNO (subdest
) != FRAME_POINTER_REGNUM
2214 && (HARD_FRAME_POINTER_IS_FRAME_POINTER
2215 || REGNO (subdest
) != HARD_FRAME_POINTER_REGNUM
)
2216 && (FRAME_POINTER_REGNUM
== ARG_POINTER_REGNUM
2217 || (REGNO (subdest
) != ARG_POINTER_REGNUM
2218 || ! fixed_regs
[REGNO (subdest
)]))
2219 && REGNO (subdest
) != STACK_POINTER_REGNUM
)
2221 if (*pi3dest_killed
)
2224 *pi3dest_killed
= subdest
;
2228 else if (GET_CODE (x
) == PARALLEL
)
2232 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
2233 if (! combinable_i3pat (i3
, &XVECEXP (x
, 0, i
), i2dest
, i1dest
, i0dest
,
2234 i1_not_in_src
, i0_not_in_src
, pi3dest_killed
))
2241 /* Return 1 if X is an arithmetic expression that contains a multiplication
2242 and division. We don't count multiplications by powers of two here. */
2245 contains_muldiv (rtx x
)
2247 switch (GET_CODE (x
))
2249 case MOD
: case DIV
: case UMOD
: case UDIV
:
2253 return ! (CONST_INT_P (XEXP (x
, 1))
2254 && exact_log2 (UINTVAL (XEXP (x
, 1))) >= 0);
2257 return contains_muldiv (XEXP (x
, 0))
2258 || contains_muldiv (XEXP (x
, 1));
2261 return contains_muldiv (XEXP (x
, 0));
2267 /* Determine whether INSN can be used in a combination. Return nonzero if
2268 not. This is used in try_combine to detect early some cases where we
2269 can't perform combinations. */
2272 cant_combine_insn_p (rtx_insn
*insn
)
2277 /* If this isn't really an insn, we can't do anything.
2278 This can occur when flow deletes an insn that it has merged into an
2279 auto-increment address. */
2280 if (! INSN_P (insn
))
2283 /* Never combine loads and stores involving hard regs that are likely
2284 to be spilled. The register allocator can usually handle such
2285 reg-reg moves by tying. If we allow the combiner to make
2286 substitutions of likely-spilled regs, reload might die.
2287 As an exception, we allow combinations involving fixed regs; these are
2288 not available to the register allocator so there's no risk involved. */
2290 set
= single_set (insn
);
2293 src
= SET_SRC (set
);
2294 dest
= SET_DEST (set
);
2295 if (GET_CODE (src
) == SUBREG
)
2296 src
= SUBREG_REG (src
);
2297 if (GET_CODE (dest
) == SUBREG
)
2298 dest
= SUBREG_REG (dest
);
2299 if (REG_P (src
) && REG_P (dest
)
2300 && ((HARD_REGISTER_P (src
)
2301 && ! TEST_HARD_REG_BIT (fixed_reg_set
, REGNO (src
))
2302 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (REGNO (src
))))
2303 || (HARD_REGISTER_P (dest
)
2304 && ! TEST_HARD_REG_BIT (fixed_reg_set
, REGNO (dest
))
2305 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (REGNO (dest
))))))
2311 struct likely_spilled_retval_info
2313 unsigned regno
, nregs
;
2317 /* Called via note_stores by likely_spilled_retval_p. Remove from info->mask
2318 hard registers that are known to be written to / clobbered in full. */
2320 likely_spilled_retval_1 (rtx x
, const_rtx set
, void *data
)
2322 struct likely_spilled_retval_info
*const info
=
2323 (struct likely_spilled_retval_info
*) data
;
2324 unsigned regno
, nregs
;
2327 if (!REG_P (XEXP (set
, 0)))
2330 if (regno
>= info
->regno
+ info
->nregs
)
2332 nregs
= REG_NREGS (x
);
2333 if (regno
+ nregs
<= info
->regno
)
2335 new_mask
= (2U << (nregs
- 1)) - 1;
2336 if (regno
< info
->regno
)
2337 new_mask
>>= info
->regno
- regno
;
2339 new_mask
<<= regno
- info
->regno
;
2340 info
->mask
&= ~new_mask
;
2343 /* Return nonzero iff part of the return value is live during INSN, and
2344 it is likely spilled. This can happen when more than one insn is needed
2345 to copy the return value, e.g. when we consider to combine into the
2346 second copy insn for a complex value. */
2349 likely_spilled_retval_p (rtx_insn
*insn
)
2351 rtx_insn
*use
= BB_END (this_basic_block
);
2354 unsigned regno
, nregs
;
2355 /* We assume here that no machine mode needs more than
2356 32 hard registers when the value overlaps with a register
2357 for which TARGET_FUNCTION_VALUE_REGNO_P is true. */
2359 struct likely_spilled_retval_info info
;
2361 if (!NONJUMP_INSN_P (use
) || GET_CODE (PATTERN (use
)) != USE
|| insn
== use
)
2363 reg
= XEXP (PATTERN (use
), 0);
2364 if (!REG_P (reg
) || !targetm
.calls
.function_value_regno_p (REGNO (reg
)))
2366 regno
= REGNO (reg
);
2367 nregs
= REG_NREGS (reg
);
2370 mask
= (2U << (nregs
- 1)) - 1;
2372 /* Disregard parts of the return value that are set later. */
2376 for (p
= PREV_INSN (use
); info
.mask
&& p
!= insn
; p
= PREV_INSN (p
))
2378 note_stores (PATTERN (p
), likely_spilled_retval_1
, &info
);
2381 /* Check if any of the (probably) live return value registers is
2386 if ((mask
& 1 << nregs
)
2387 && targetm
.class_likely_spilled_p (REGNO_REG_CLASS (regno
+ nregs
)))
2393 /* Adjust INSN after we made a change to its destination.
2395 Changing the destination can invalidate notes that say something about
2396 the results of the insn and a LOG_LINK pointing to the insn. */
2399 adjust_for_new_dest (rtx_insn
*insn
)
2401 /* For notes, be conservative and simply remove them. */
2402 remove_reg_equal_equiv_notes (insn
);
2404 /* The new insn will have a destination that was previously the destination
2405 of an insn just above it. Call distribute_links to make a LOG_LINK from
2406 the next use of that destination. */
2408 rtx set
= single_set (insn
);
2411 rtx reg
= SET_DEST (set
);
2413 while (GET_CODE (reg
) == ZERO_EXTRACT
2414 || GET_CODE (reg
) == STRICT_LOW_PART
2415 || GET_CODE (reg
) == SUBREG
)
2416 reg
= XEXP (reg
, 0);
2417 gcc_assert (REG_P (reg
));
2419 distribute_links (alloc_insn_link (insn
, REGNO (reg
), NULL
));
2421 df_insn_rescan (insn
);
2424 /* Return TRUE if combine can reuse reg X in mode MODE.
2425 ADDED_SETS is nonzero if the original set is still required. */
2427 can_change_dest_mode (rtx x
, int added_sets
, machine_mode mode
)
2435 /* Allow hard registers if the new mode is legal, and occupies no more
2436 registers than the old mode. */
2437 if (regno
< FIRST_PSEUDO_REGISTER
)
2438 return (HARD_REGNO_MODE_OK (regno
, mode
)
2439 && REG_NREGS (x
) >= hard_regno_nregs
[regno
][mode
]);
2441 /* Or a pseudo that is only used once. */
2442 return (regno
< reg_n_sets_max
2443 && REG_N_SETS (regno
) == 1
2445 && !REG_USERVAR_P (x
));
2449 /* Check whether X, the destination of a set, refers to part of
2450 the register specified by REG. */
2453 reg_subword_p (rtx x
, rtx reg
)
2455 /* Check that reg is an integer mode register. */
2456 if (!REG_P (reg
) || GET_MODE_CLASS (GET_MODE (reg
)) != MODE_INT
)
2459 if (GET_CODE (x
) == STRICT_LOW_PART
2460 || GET_CODE (x
) == ZERO_EXTRACT
)
2463 return GET_CODE (x
) == SUBREG
2464 && SUBREG_REG (x
) == reg
2465 && GET_MODE_CLASS (GET_MODE (x
)) == MODE_INT
;
2468 /* Delete the unconditional jump INSN and adjust the CFG correspondingly.
2469 Note that the INSN should be deleted *after* removing dead edges, so
2470 that the kept edge is the fallthrough edge for a (set (pc) (pc))
2471 but not for a (set (pc) (label_ref FOO)). */
2474 update_cfg_for_uncondjump (rtx_insn
*insn
)
2476 basic_block bb
= BLOCK_FOR_INSN (insn
);
2477 gcc_assert (BB_END (bb
) == insn
);
2479 purge_dead_edges (bb
);
2482 if (EDGE_COUNT (bb
->succs
) == 1)
2486 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2488 /* Remove barriers from the footer if there are any. */
2489 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2490 if (BARRIER_P (insn
))
2492 if (PREV_INSN (insn
))
2493 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2495 BB_FOOTER (bb
) = NEXT_INSN (insn
);
2496 if (NEXT_INSN (insn
))
2497 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2499 else if (LABEL_P (insn
))
2504 /* Return whether PAT is a PARALLEL of exactly N register SETs followed
2505 by an arbitrary number of CLOBBERs. */
2507 is_parallel_of_n_reg_sets (rtx pat
, int n
)
2509 if (GET_CODE (pat
) != PARALLEL
)
2512 int len
= XVECLEN (pat
, 0);
2517 for (i
= 0; i
< n
; i
++)
2518 if (GET_CODE (XVECEXP (pat
, 0, i
)) != SET
2519 || !REG_P (SET_DEST (XVECEXP (pat
, 0, i
))))
2521 for ( ; i
< len
; i
++)
2522 if (GET_CODE (XVECEXP (pat
, 0, i
)) != CLOBBER
2523 || XEXP (XVECEXP (pat
, 0, i
), 0) == const0_rtx
)
2529 /* Return whether INSN, a PARALLEL of N register SETs (and maybe some
2530 CLOBBERs), can be split into individual SETs in that order, without
2531 changing semantics. */
2533 can_split_parallel_of_n_reg_sets (rtx_insn
*insn
, int n
)
2535 if (!insn_nothrow_p (insn
))
2538 rtx pat
= PATTERN (insn
);
2541 for (i
= 0; i
< n
; i
++)
2543 if (side_effects_p (SET_SRC (XVECEXP (pat
, 0, i
))))
2546 rtx reg
= SET_DEST (XVECEXP (pat
, 0, i
));
2548 for (j
= i
+ 1; j
< n
; j
++)
2549 if (reg_referenced_p (reg
, XVECEXP (pat
, 0, j
)))
2556 /* Try to combine the insns I0, I1 and I2 into I3.
2557 Here I0, I1 and I2 appear earlier than I3.
2558 I0 and I1 can be zero; then we combine just I2 into I3, or I1 and I2 into
2561 If we are combining more than two insns and the resulting insn is not
2562 recognized, try splitting it into two insns. If that happens, I2 and I3
2563 are retained and I1/I0 are pseudo-deleted by turning them into a NOTE.
2564 Otherwise, I0, I1 and I2 are pseudo-deleted.
2566 Return 0 if the combination does not work. Then nothing is changed.
2567 If we did the combination, return the insn at which combine should
2570 Set NEW_DIRECT_JUMP_P to a nonzero value if try_combine creates a
2571 new direct jump instruction.
2573 LAST_COMBINED_INSN is either I3, or some insn after I3 that has
2574 been I3 passed to an earlier try_combine within the same basic
2578 try_combine (rtx_insn
*i3
, rtx_insn
*i2
, rtx_insn
*i1
, rtx_insn
*i0
,
2579 int *new_direct_jump_p
, rtx_insn
*last_combined_insn
)
2581 /* New patterns for I3 and I2, respectively. */
2582 rtx newpat
, newi2pat
= 0;
2583 rtvec newpat_vec_with_clobbers
= 0;
2584 int substed_i2
= 0, substed_i1
= 0, substed_i0
= 0;
2585 /* Indicates need to preserve SET in I0, I1 or I2 in I3 if it is not
2587 int added_sets_0
, added_sets_1
, added_sets_2
;
2588 /* Total number of SETs to put into I3. */
2590 /* Nonzero if I2's or I1's body now appears in I3. */
2591 int i2_is_used
= 0, i1_is_used
= 0;
2592 /* INSN_CODEs for new I3, new I2, and user of condition code. */
2593 int insn_code_number
, i2_code_number
= 0, other_code_number
= 0;
2594 /* Contains I3 if the destination of I3 is used in its source, which means
2595 that the old life of I3 is being killed. If that usage is placed into
2596 I2 and not in I3, a REG_DEAD note must be made. */
2597 rtx i3dest_killed
= 0;
2598 /* SET_DEST and SET_SRC of I2, I1 and I0. */
2599 rtx i2dest
= 0, i2src
= 0, i1dest
= 0, i1src
= 0, i0dest
= 0, i0src
= 0;
2600 /* Copy of SET_SRC of I1 and I0, if needed. */
2601 rtx i1src_copy
= 0, i0src_copy
= 0, i0src_copy2
= 0;
2602 /* Set if I2DEST was reused as a scratch register. */
2603 bool i2scratch
= false;
2604 /* The PATTERNs of I0, I1, and I2, or a copy of them in certain cases. */
2605 rtx i0pat
= 0, i1pat
= 0, i2pat
= 0;
2606 /* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */
2607 int i2dest_in_i2src
= 0, i1dest_in_i1src
= 0, i2dest_in_i1src
= 0;
2608 int i0dest_in_i0src
= 0, i1dest_in_i0src
= 0, i2dest_in_i0src
= 0;
2609 int i2dest_killed
= 0, i1dest_killed
= 0, i0dest_killed
= 0;
2610 int i1_feeds_i2_n
= 0, i0_feeds_i2_n
= 0, i0_feeds_i1_n
= 0;
2611 /* Notes that must be added to REG_NOTES in I3 and I2. */
2612 rtx new_i3_notes
, new_i2_notes
;
2613 /* Notes that we substituted I3 into I2 instead of the normal case. */
2614 int i3_subst_into_i2
= 0;
2615 /* Notes that I1, I2 or I3 is a MULT operation. */
2618 int changed_i3_dest
= 0;
2621 rtx_insn
*temp_insn
;
2623 struct insn_link
*link
;
2625 rtx new_other_notes
;
2628 /* Immediately return if any of I0,I1,I2 are the same insn (I3 can
2630 if (i1
== i2
|| i0
== i2
|| (i0
&& i0
== i1
))
2633 /* Only try four-insn combinations when there's high likelihood of
2634 success. Look for simple insns, such as loads of constants or
2635 binary operations involving a constant. */
2643 if (!flag_expensive_optimizations
)
2646 for (i
= 0; i
< 4; i
++)
2648 rtx_insn
*insn
= i
== 0 ? i0
: i
== 1 ? i1
: i
== 2 ? i2
: i3
;
2649 rtx set
= single_set (insn
);
2653 src
= SET_SRC (set
);
2654 if (CONSTANT_P (src
))
2659 else if (BINARY_P (src
) && CONSTANT_P (XEXP (src
, 1)))
2661 else if (GET_CODE (src
) == ASHIFT
|| GET_CODE (src
) == ASHIFTRT
2662 || GET_CODE (src
) == LSHIFTRT
)
2666 /* If I0 loads a memory and I3 sets the same memory, then I1 and I2
2667 are likely manipulating its value. Ideally we'll be able to combine
2668 all four insns into a bitfield insertion of some kind.
2670 Note the source in I0 might be inside a sign/zero extension and the
2671 memory modes in I0 and I3 might be different. So extract the address
2672 from the destination of I3 and search for it in the source of I0.
2674 In the event that there's a match but the source/dest do not actually
2675 refer to the same memory, the worst that happens is we try some
2676 combinations that we wouldn't have otherwise. */
2677 if ((set0
= single_set (i0
))
2678 /* Ensure the source of SET0 is a MEM, possibly buried inside
2680 && (GET_CODE (SET_SRC (set0
)) == MEM
2681 || ((GET_CODE (SET_SRC (set0
)) == ZERO_EXTEND
2682 || GET_CODE (SET_SRC (set0
)) == SIGN_EXTEND
)
2683 && GET_CODE (XEXP (SET_SRC (set0
), 0)) == MEM
))
2684 && (set3
= single_set (i3
))
2685 /* Ensure the destination of SET3 is a MEM. */
2686 && GET_CODE (SET_DEST (set3
)) == MEM
2687 /* Would it be better to extract the base address for the MEM
2688 in SET3 and look for that? I don't have cases where it matters
2689 but I could envision such cases. */
2690 && rtx_referenced_p (XEXP (SET_DEST (set3
), 0), SET_SRC (set0
)))
2693 if (ngood
< 2 && nshift
< 2)
2697 /* Exit early if one of the insns involved can't be used for
2700 || (i1
&& CALL_P (i1
))
2701 || (i0
&& CALL_P (i0
))
2702 || cant_combine_insn_p (i3
)
2703 || cant_combine_insn_p (i2
)
2704 || (i1
&& cant_combine_insn_p (i1
))
2705 || (i0
&& cant_combine_insn_p (i0
))
2706 || likely_spilled_retval_p (i3
))
2710 undobuf
.other_insn
= 0;
2712 /* Reset the hard register usage information. */
2713 CLEAR_HARD_REG_SET (newpat_used_regs
);
2715 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2718 fprintf (dump_file
, "\nTrying %d, %d, %d -> %d:\n",
2719 INSN_UID (i0
), INSN_UID (i1
), INSN_UID (i2
), INSN_UID (i3
));
2721 fprintf (dump_file
, "\nTrying %d, %d -> %d:\n",
2722 INSN_UID (i1
), INSN_UID (i2
), INSN_UID (i3
));
2724 fprintf (dump_file
, "\nTrying %d -> %d:\n",
2725 INSN_UID (i2
), INSN_UID (i3
));
2728 /* If multiple insns feed into one of I2 or I3, they can be in any
2729 order. To simplify the code below, reorder them in sequence. */
2730 if (i0
&& DF_INSN_LUID (i0
) > DF_INSN_LUID (i2
))
2732 if (i0
&& DF_INSN_LUID (i0
) > DF_INSN_LUID (i1
))
2734 if (i1
&& DF_INSN_LUID (i1
) > DF_INSN_LUID (i2
))
2737 added_links_insn
= 0;
2739 /* First check for one important special case that the code below will
2740 not handle. Namely, the case where I1 is zero, I2 is a PARALLEL
2741 and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case,
2742 we may be able to replace that destination with the destination of I3.
2743 This occurs in the common code where we compute both a quotient and
2744 remainder into a structure, in which case we want to do the computation
2745 directly into the structure to avoid register-register copies.
2747 Note that this case handles both multiple sets in I2 and also cases
2748 where I2 has a number of CLOBBERs inside the PARALLEL.
2750 We make very conservative checks below and only try to handle the
2751 most common cases of this. For example, we only handle the case
2752 where I2 and I3 are adjacent to avoid making difficult register
2755 if (i1
== 0 && NONJUMP_INSN_P (i3
) && GET_CODE (PATTERN (i3
)) == SET
2756 && REG_P (SET_SRC (PATTERN (i3
)))
2757 && REGNO (SET_SRC (PATTERN (i3
))) >= FIRST_PSEUDO_REGISTER
2758 && find_reg_note (i3
, REG_DEAD
, SET_SRC (PATTERN (i3
)))
2759 && GET_CODE (PATTERN (i2
)) == PARALLEL
2760 && ! side_effects_p (SET_DEST (PATTERN (i3
)))
2761 /* If the dest of I3 is a ZERO_EXTRACT or STRICT_LOW_PART, the code
2762 below would need to check what is inside (and reg_overlap_mentioned_p
2763 doesn't support those codes anyway). Don't allow those destinations;
2764 the resulting insn isn't likely to be recognized anyway. */
2765 && GET_CODE (SET_DEST (PATTERN (i3
))) != ZERO_EXTRACT
2766 && GET_CODE (SET_DEST (PATTERN (i3
))) != STRICT_LOW_PART
2767 && ! reg_overlap_mentioned_p (SET_SRC (PATTERN (i3
)),
2768 SET_DEST (PATTERN (i3
)))
2769 && next_active_insn (i2
) == i3
)
2771 rtx p2
= PATTERN (i2
);
2773 /* Make sure that the destination of I3,
2774 which we are going to substitute into one output of I2,
2775 is not used within another output of I2. We must avoid making this:
2776 (parallel [(set (mem (reg 69)) ...)
2777 (set (reg 69) ...)])
2778 which is not well-defined as to order of actions.
2779 (Besides, reload can't handle output reloads for this.)
2781 The problem can also happen if the dest of I3 is a memory ref,
2782 if another dest in I2 is an indirect memory ref. */
2783 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2784 if ((GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2785 || GET_CODE (XVECEXP (p2
, 0, i
)) == CLOBBER
)
2786 && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3
)),
2787 SET_DEST (XVECEXP (p2
, 0, i
))))
2790 /* Make sure this PARALLEL is not an asm. We do not allow combining
2791 that usually (see can_combine_p), so do not here either. */
2792 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2793 if (GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2794 && GET_CODE (SET_SRC (XVECEXP (p2
, 0, i
))) == ASM_OPERANDS
)
2797 if (i
== XVECLEN (p2
, 0))
2798 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
2799 if (GET_CODE (XVECEXP (p2
, 0, i
)) == SET
2800 && SET_DEST (XVECEXP (p2
, 0, i
)) == SET_SRC (PATTERN (i3
)))
2805 subst_low_luid
= DF_INSN_LUID (i2
);
2807 added_sets_2
= added_sets_1
= added_sets_0
= 0;
2808 i2src
= SET_SRC (XVECEXP (p2
, 0, i
));
2809 i2dest
= SET_DEST (XVECEXP (p2
, 0, i
));
2810 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2812 /* Replace the dest in I2 with our dest and make the resulting
2813 insn the new pattern for I3. Then skip to where we validate
2814 the pattern. Everything was set up above. */
2815 SUBST (SET_DEST (XVECEXP (p2
, 0, i
)), SET_DEST (PATTERN (i3
)));
2817 i3_subst_into_i2
= 1;
2818 goto validate_replacement
;
2822 /* If I2 is setting a pseudo to a constant and I3 is setting some
2823 sub-part of it to another constant, merge them by making a new
2826 && (temp_expr
= single_set (i2
)) != 0
2827 && CONST_SCALAR_INT_P (SET_SRC (temp_expr
))
2828 && GET_CODE (PATTERN (i3
)) == SET
2829 && CONST_SCALAR_INT_P (SET_SRC (PATTERN (i3
)))
2830 && reg_subword_p (SET_DEST (PATTERN (i3
)), SET_DEST (temp_expr
)))
2832 rtx dest
= SET_DEST (PATTERN (i3
));
2836 if (GET_CODE (dest
) == ZERO_EXTRACT
)
2838 if (CONST_INT_P (XEXP (dest
, 1))
2839 && CONST_INT_P (XEXP (dest
, 2)))
2841 width
= INTVAL (XEXP (dest
, 1));
2842 offset
= INTVAL (XEXP (dest
, 2));
2843 dest
= XEXP (dest
, 0);
2844 if (BITS_BIG_ENDIAN
)
2845 offset
= GET_MODE_PRECISION (GET_MODE (dest
)) - width
- offset
;
2850 if (GET_CODE (dest
) == STRICT_LOW_PART
)
2851 dest
= XEXP (dest
, 0);
2852 width
= GET_MODE_PRECISION (GET_MODE (dest
));
2858 /* If this is the low part, we're done. */
2859 if (subreg_lowpart_p (dest
))
2861 /* Handle the case where inner is twice the size of outer. */
2862 else if (GET_MODE_PRECISION (GET_MODE (SET_DEST (temp_expr
)))
2863 == 2 * GET_MODE_PRECISION (GET_MODE (dest
)))
2864 offset
+= GET_MODE_PRECISION (GET_MODE (dest
));
2865 /* Otherwise give up for now. */
2872 rtx inner
= SET_SRC (PATTERN (i3
));
2873 rtx outer
= SET_SRC (temp_expr
);
2876 = wi::insert (std::make_pair (outer
, GET_MODE (SET_DEST (temp_expr
))),
2877 std::make_pair (inner
, GET_MODE (dest
)),
2882 subst_low_luid
= DF_INSN_LUID (i2
);
2883 added_sets_2
= added_sets_1
= added_sets_0
= 0;
2884 i2dest
= SET_DEST (temp_expr
);
2885 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2887 /* Replace the source in I2 with the new constant and make the
2888 resulting insn the new pattern for I3. Then skip to where we
2889 validate the pattern. Everything was set up above. */
2890 SUBST (SET_SRC (temp_expr
),
2891 immed_wide_int_const (o
, GET_MODE (SET_DEST (temp_expr
))));
2893 newpat
= PATTERN (i2
);
2895 /* The dest of I3 has been replaced with the dest of I2. */
2896 changed_i3_dest
= 1;
2897 goto validate_replacement
;
2901 /* If we have no I1 and I2 looks like:
2902 (parallel [(set (reg:CC X) (compare:CC OP (const_int 0)))
2904 make up a dummy I1 that is
2907 (set (reg:CC X) (compare:CC Y (const_int 0)))
2909 (We can ignore any trailing CLOBBERs.)
2911 This undoes a previous combination and allows us to match a branch-and-
2914 if (!HAVE_cc0
&& i1
== 0
2915 && is_parallel_of_n_reg_sets (PATTERN (i2
), 2)
2916 && (GET_MODE_CLASS (GET_MODE (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0))))
2918 && GET_CODE (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0))) == COMPARE
2919 && XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 1) == const0_rtx
2920 && rtx_equal_p (XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 0),
2921 SET_SRC (XVECEXP (PATTERN (i2
), 0, 1)))
2922 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0)), i2
, i3
)
2923 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 1)), i2
, i3
))
2925 /* We make I1 with the same INSN_UID as I2. This gives it
2926 the same DF_INSN_LUID for value tracking. Our fake I1 will
2927 never appear in the insn stream so giving it the same INSN_UID
2928 as I2 will not cause a problem. */
2930 i1
= gen_rtx_INSN (VOIDmode
, NULL
, i2
, BLOCK_FOR_INSN (i2
),
2931 XVECEXP (PATTERN (i2
), 0, 1), INSN_LOCATION (i2
),
2933 INSN_UID (i1
) = INSN_UID (i2
);
2935 SUBST (PATTERN (i2
), XVECEXP (PATTERN (i2
), 0, 0));
2936 SUBST (XEXP (SET_SRC (PATTERN (i2
)), 0),
2937 SET_DEST (PATTERN (i1
)));
2938 unsigned int regno
= REGNO (SET_DEST (PATTERN (i1
)));
2939 SUBST_LINK (LOG_LINKS (i2
),
2940 alloc_insn_link (i1
, regno
, LOG_LINKS (i2
)));
2943 /* If I2 is a PARALLEL of two SETs of REGs (and perhaps some CLOBBERs),
2944 make those two SETs separate I1 and I2 insns, and make an I0 that is
2946 if (!HAVE_cc0
&& i0
== 0
2947 && is_parallel_of_n_reg_sets (PATTERN (i2
), 2)
2948 && can_split_parallel_of_n_reg_sets (i2
, 2)
2949 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0)), i2
, i3
)
2950 && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2
), 0, 1)), i2
, i3
))
2952 /* If there is no I1, there is no I0 either. */
2955 /* We make I1 with the same INSN_UID as I2. This gives it
2956 the same DF_INSN_LUID for value tracking. Our fake I1 will
2957 never appear in the insn stream so giving it the same INSN_UID
2958 as I2 will not cause a problem. */
2960 i1
= gen_rtx_INSN (VOIDmode
, NULL
, i2
, BLOCK_FOR_INSN (i2
),
2961 XVECEXP (PATTERN (i2
), 0, 0), INSN_LOCATION (i2
),
2963 INSN_UID (i1
) = INSN_UID (i2
);
2965 SUBST (PATTERN (i2
), XVECEXP (PATTERN (i2
), 0, 1));
2968 /* Verify that I2 and I1 are valid for combining. */
2969 if (! can_combine_p (i2
, i3
, i0
, i1
, NULL
, NULL
, &i2dest
, &i2src
)
2970 || (i1
&& ! can_combine_p (i1
, i3
, i0
, NULL
, i2
, NULL
,
2972 || (i0
&& ! can_combine_p (i0
, i3
, NULL
, NULL
, i1
, i2
,
2979 /* Record whether I2DEST is used in I2SRC and similarly for the other
2980 cases. Knowing this will help in register status updating below. */
2981 i2dest_in_i2src
= reg_overlap_mentioned_p (i2dest
, i2src
);
2982 i1dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i1dest
, i1src
);
2983 i2dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i2dest
, i1src
);
2984 i0dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i0dest
, i0src
);
2985 i1dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i1dest
, i0src
);
2986 i2dest_in_i0src
= i0
&& reg_overlap_mentioned_p (i2dest
, i0src
);
2987 i2dest_killed
= dead_or_set_p (i2
, i2dest
);
2988 i1dest_killed
= i1
&& dead_or_set_p (i1
, i1dest
);
2989 i0dest_killed
= i0
&& dead_or_set_p (i0
, i0dest
);
2991 /* For the earlier insns, determine which of the subsequent ones they
2993 i1_feeds_i2_n
= i1
&& insn_a_feeds_b (i1
, i2
);
2994 i0_feeds_i1_n
= i0
&& insn_a_feeds_b (i0
, i1
);
2995 i0_feeds_i2_n
= (i0
&& (!i0_feeds_i1_n
? insn_a_feeds_b (i0
, i2
)
2996 : (!reg_overlap_mentioned_p (i1dest
, i0dest
)
2997 && reg_overlap_mentioned_p (i0dest
, i2src
))));
2999 /* Ensure that I3's pattern can be the destination of combines. */
3000 if (! combinable_i3pat (i3
, &PATTERN (i3
), i2dest
, i1dest
, i0dest
,
3001 i1
&& i2dest_in_i1src
&& !i1_feeds_i2_n
,
3002 i0
&& ((i2dest_in_i0src
&& !i0_feeds_i2_n
)
3003 || (i1dest_in_i0src
&& !i0_feeds_i1_n
)),
3010 /* See if any of the insns is a MULT operation. Unless one is, we will
3011 reject a combination that is, since it must be slower. Be conservative
3013 if (GET_CODE (i2src
) == MULT
3014 || (i1
!= 0 && GET_CODE (i1src
) == MULT
)
3015 || (i0
!= 0 && GET_CODE (i0src
) == MULT
)
3016 || (GET_CODE (PATTERN (i3
)) == SET
3017 && GET_CODE (SET_SRC (PATTERN (i3
))) == MULT
))
3020 /* If I3 has an inc, then give up if I1 or I2 uses the reg that is inc'd.
3021 We used to do this EXCEPT in one case: I3 has a post-inc in an
3022 output operand. However, that exception can give rise to insns like
3024 which is a famous insn on the PDP-11 where the value of r3 used as the
3025 source was model-dependent. Avoid this sort of thing. */
3028 if (!(GET_CODE (PATTERN (i3
)) == SET
3029 && REG_P (SET_SRC (PATTERN (i3
)))
3030 && MEM_P (SET_DEST (PATTERN (i3
)))
3031 && (GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_INC
3032 || GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_DEC
)))
3033 /* It's not the exception. */
3038 for (link
= REG_NOTES (i3
); link
; link
= XEXP (link
, 1))
3039 if (REG_NOTE_KIND (link
) == REG_INC
3040 && (reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i2
))
3042 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i1
)))))
3049 /* See if the SETs in I1 or I2 need to be kept around in the merged
3050 instruction: whenever the value set there is still needed past I3.
3051 For the SET in I2, this is easy: we see if I2DEST dies or is set in I3.
3053 For the SET in I1, we have two cases: if I1 and I2 independently feed
3054 into I3, the set in I1 needs to be kept around unless I1DEST dies
3055 or is set in I3. Otherwise (if I1 feeds I2 which feeds I3), the set
3056 in I1 needs to be kept around unless I1DEST dies or is set in either
3057 I2 or I3. The same considerations apply to I0. */
3059 added_sets_2
= !dead_or_set_p (i3
, i2dest
);
3062 added_sets_1
= !(dead_or_set_p (i3
, i1dest
)
3063 || (i1_feeds_i2_n
&& dead_or_set_p (i2
, i1dest
)));
3068 added_sets_0
= !(dead_or_set_p (i3
, i0dest
)
3069 || (i0_feeds_i1_n
&& dead_or_set_p (i1
, i0dest
))
3070 || ((i0_feeds_i2_n
|| (i0_feeds_i1_n
&& i1_feeds_i2_n
))
3071 && dead_or_set_p (i2
, i0dest
)));
3075 /* We are about to copy insns for the case where they need to be kept
3076 around. Check that they can be copied in the merged instruction. */
3078 if (targetm
.cannot_copy_insn_p
3079 && ((added_sets_2
&& targetm
.cannot_copy_insn_p (i2
))
3080 || (i1
&& added_sets_1
&& targetm
.cannot_copy_insn_p (i1
))
3081 || (i0
&& added_sets_0
&& targetm
.cannot_copy_insn_p (i0
))))
3087 /* If the set in I2 needs to be kept around, we must make a copy of
3088 PATTERN (I2), so that when we substitute I1SRC for I1DEST in
3089 PATTERN (I2), we are only substituting for the original I1DEST, not into
3090 an already-substituted copy. This also prevents making self-referential
3091 rtx. If I2 is a PARALLEL, we just need the piece that assigns I2SRC to
3096 if (GET_CODE (PATTERN (i2
)) == PARALLEL
)
3097 i2pat
= gen_rtx_SET (i2dest
, copy_rtx (i2src
));
3099 i2pat
= copy_rtx (PATTERN (i2
));
3104 if (GET_CODE (PATTERN (i1
)) == PARALLEL
)
3105 i1pat
= gen_rtx_SET (i1dest
, copy_rtx (i1src
));
3107 i1pat
= copy_rtx (PATTERN (i1
));
3112 if (GET_CODE (PATTERN (i0
)) == PARALLEL
)
3113 i0pat
= gen_rtx_SET (i0dest
, copy_rtx (i0src
));
3115 i0pat
= copy_rtx (PATTERN (i0
));
3120 /* Substitute in the latest insn for the regs set by the earlier ones. */
3122 maxreg
= max_reg_num ();
3126 /* Many machines that don't use CC0 have insns that can both perform an
3127 arithmetic operation and set the condition code. These operations will
3128 be represented as a PARALLEL with the first element of the vector
3129 being a COMPARE of an arithmetic operation with the constant zero.
3130 The second element of the vector will set some pseudo to the result
3131 of the same arithmetic operation. If we simplify the COMPARE, we won't
3132 match such a pattern and so will generate an extra insn. Here we test
3133 for this case, where both the comparison and the operation result are
3134 needed, and make the PARALLEL by just replacing I2DEST in I3SRC with
3135 I2SRC. Later we will make the PARALLEL that contains I2. */
3137 if (!HAVE_cc0
&& i1
== 0 && added_sets_2
&& GET_CODE (PATTERN (i3
)) == SET
3138 && GET_CODE (SET_SRC (PATTERN (i3
))) == COMPARE
3139 && CONST_INT_P (XEXP (SET_SRC (PATTERN (i3
)), 1))
3140 && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3
)), 0), i2dest
))
3143 rtx
*cc_use_loc
= NULL
;
3144 rtx_insn
*cc_use_insn
= NULL
;
3145 rtx op0
= i2src
, op1
= XEXP (SET_SRC (PATTERN (i3
)), 1);
3146 machine_mode compare_mode
, orig_compare_mode
;
3147 enum rtx_code compare_code
= UNKNOWN
, orig_compare_code
= UNKNOWN
;
3149 newpat
= PATTERN (i3
);
3150 newpat_dest
= SET_DEST (newpat
);
3151 compare_mode
= orig_compare_mode
= GET_MODE (newpat_dest
);
3153 if (undobuf
.other_insn
== 0
3154 && (cc_use_loc
= find_single_use (SET_DEST (newpat
), i3
,
3157 compare_code
= orig_compare_code
= GET_CODE (*cc_use_loc
);
3158 compare_code
= simplify_compare_const (compare_code
,
3159 GET_MODE (i2dest
), op0
, &op1
);
3160 target_canonicalize_comparison (&compare_code
, &op0
, &op1
, 1);
3163 /* Do the rest only if op1 is const0_rtx, which may be the
3164 result of simplification. */
3165 if (op1
== const0_rtx
)
3167 /* If a single use of the CC is found, prepare to modify it
3168 when SELECT_CC_MODE returns a new CC-class mode, or when
3169 the above simplify_compare_const() returned a new comparison
3170 operator. undobuf.other_insn is assigned the CC use insn
3171 when modifying it. */
3174 #ifdef SELECT_CC_MODE
3175 machine_mode new_mode
3176 = SELECT_CC_MODE (compare_code
, op0
, op1
);
3177 if (new_mode
!= orig_compare_mode
3178 && can_change_dest_mode (SET_DEST (newpat
),
3179 added_sets_2
, new_mode
))
3181 unsigned int regno
= REGNO (newpat_dest
);
3182 compare_mode
= new_mode
;
3183 if (regno
< FIRST_PSEUDO_REGISTER
)
3184 newpat_dest
= gen_rtx_REG (compare_mode
, regno
);
3187 SUBST_MODE (regno_reg_rtx
[regno
], compare_mode
);
3188 newpat_dest
= regno_reg_rtx
[regno
];
3192 /* Cases for modifying the CC-using comparison. */
3193 if (compare_code
!= orig_compare_code
3194 /* ??? Do we need to verify the zero rtx? */
3195 && XEXP (*cc_use_loc
, 1) == const0_rtx
)
3197 /* Replace cc_use_loc with entire new RTX. */
3199 gen_rtx_fmt_ee (compare_code
, compare_mode
,
3200 newpat_dest
, const0_rtx
));
3201 undobuf
.other_insn
= cc_use_insn
;
3203 else if (compare_mode
!= orig_compare_mode
)
3205 /* Just replace the CC reg with a new mode. */
3206 SUBST (XEXP (*cc_use_loc
, 0), newpat_dest
);
3207 undobuf
.other_insn
= cc_use_insn
;
3211 /* Now we modify the current newpat:
3212 First, SET_DEST(newpat) is updated if the CC mode has been
3213 altered. For targets without SELECT_CC_MODE, this should be
3215 if (compare_mode
!= orig_compare_mode
)
3216 SUBST (SET_DEST (newpat
), newpat_dest
);
3217 /* This is always done to propagate i2src into newpat. */
3218 SUBST (SET_SRC (newpat
),
3219 gen_rtx_COMPARE (compare_mode
, op0
, op1
));
3220 /* Create new version of i2pat if needed; the below PARALLEL
3221 creation needs this to work correctly. */
3222 if (! rtx_equal_p (i2src
, op0
))
3223 i2pat
= gen_rtx_SET (i2dest
, op0
);
3228 if (i2_is_used
== 0)
3230 /* It is possible that the source of I2 or I1 may be performing
3231 an unneeded operation, such as a ZERO_EXTEND of something
3232 that is known to have the high part zero. Handle that case
3233 by letting subst look at the inner insns.
3235 Another way to do this would be to have a function that tries
3236 to simplify a single insn instead of merging two or more
3237 insns. We don't do this because of the potential of infinite
3238 loops and because of the potential extra memory required.
3239 However, doing it the way we are is a bit of a kludge and
3240 doesn't catch all cases.
3242 But only do this if -fexpensive-optimizations since it slows
3243 things down and doesn't usually win.
3245 This is not done in the COMPARE case above because the
3246 unmodified I2PAT is used in the PARALLEL and so a pattern
3247 with a modified I2SRC would not match. */
3249 if (flag_expensive_optimizations
)
3251 /* Pass pc_rtx so no substitutions are done, just
3255 subst_low_luid
= DF_INSN_LUID (i1
);
3256 i1src
= subst (i1src
, pc_rtx
, pc_rtx
, 0, 0, 0);
3259 subst_low_luid
= DF_INSN_LUID (i2
);
3260 i2src
= subst (i2src
, pc_rtx
, pc_rtx
, 0, 0, 0);
3263 n_occurrences
= 0; /* `subst' counts here */
3264 subst_low_luid
= DF_INSN_LUID (i2
);
3266 /* If I1 feeds into I2 and I1DEST is in I1SRC, we need to make a unique
3267 copy of I2SRC each time we substitute it, in order to avoid creating
3268 self-referential RTL when we will be substituting I1SRC for I1DEST
3269 later. Likewise if I0 feeds into I2, either directly or indirectly
3270 through I1, and I0DEST is in I0SRC. */
3271 newpat
= subst (PATTERN (i3
), i2dest
, i2src
, 0, 0,
3272 (i1_feeds_i2_n
&& i1dest_in_i1src
)
3273 || ((i0_feeds_i2_n
|| (i0_feeds_i1_n
&& i1_feeds_i2_n
))
3274 && i0dest_in_i0src
));
3277 /* Record whether I2's body now appears within I3's body. */
3278 i2_is_used
= n_occurrences
;
3281 /* If we already got a failure, don't try to do more. Otherwise, try to
3282 substitute I1 if we have it. */
3284 if (i1
&& GET_CODE (newpat
) != CLOBBER
)
3286 /* Check that an autoincrement side-effect on I1 has not been lost.
3287 This happens if I1DEST is mentioned in I2 and dies there, and
3288 has disappeared from the new pattern. */
3289 if ((FIND_REG_INC_NOTE (i1
, NULL_RTX
) != 0
3291 && dead_or_set_p (i2
, i1dest
)
3292 && !reg_overlap_mentioned_p (i1dest
, newpat
))
3293 /* Before we can do this substitution, we must redo the test done
3294 above (see detailed comments there) that ensures I1DEST isn't
3295 mentioned in any SETs in NEWPAT that are field assignments. */
3296 || !combinable_i3pat (NULL
, &newpat
, i1dest
, NULL_RTX
, NULL_RTX
,
3304 subst_low_luid
= DF_INSN_LUID (i1
);
3306 /* If the following substitution will modify I1SRC, make a copy of it
3307 for the case where it is substituted for I1DEST in I2PAT later. */
3308 if (added_sets_2
&& i1_feeds_i2_n
)
3309 i1src_copy
= copy_rtx (i1src
);
3311 /* If I0 feeds into I1 and I0DEST is in I0SRC, we need to make a unique
3312 copy of I1SRC each time we substitute it, in order to avoid creating
3313 self-referential RTL when we will be substituting I0SRC for I0DEST
3315 newpat
= subst (newpat
, i1dest
, i1src
, 0, 0,
3316 i0_feeds_i1_n
&& i0dest_in_i0src
);
3319 /* Record whether I1's body now appears within I3's body. */
3320 i1_is_used
= n_occurrences
;
3323 /* Likewise for I0 if we have it. */
3325 if (i0
&& GET_CODE (newpat
) != CLOBBER
)
3327 if ((FIND_REG_INC_NOTE (i0
, NULL_RTX
) != 0
3328 && ((i0_feeds_i2_n
&& dead_or_set_p (i2
, i0dest
))
3329 || (i0_feeds_i1_n
&& dead_or_set_p (i1
, i0dest
)))
3330 && !reg_overlap_mentioned_p (i0dest
, newpat
))
3331 || !combinable_i3pat (NULL
, &newpat
, i0dest
, NULL_RTX
, NULL_RTX
,
3338 /* If the following substitution will modify I0SRC, make a copy of it
3339 for the case where it is substituted for I0DEST in I1PAT later. */
3340 if (added_sets_1
&& i0_feeds_i1_n
)
3341 i0src_copy
= copy_rtx (i0src
);
3342 /* And a copy for I0DEST in I2PAT substitution. */
3343 if (added_sets_2
&& ((i0_feeds_i1_n
&& i1_feeds_i2_n
)
3344 || (i0_feeds_i2_n
)))
3345 i0src_copy2
= copy_rtx (i0src
);
3348 subst_low_luid
= DF_INSN_LUID (i0
);
3349 newpat
= subst (newpat
, i0dest
, i0src
, 0, 0, 0);
3353 /* Fail if an autoincrement side-effect has been duplicated. Be careful
3354 to count all the ways that I2SRC and I1SRC can be used. */
3355 if ((FIND_REG_INC_NOTE (i2
, NULL_RTX
) != 0
3356 && i2_is_used
+ added_sets_2
> 1)
3357 || (i1
!= 0 && FIND_REG_INC_NOTE (i1
, NULL_RTX
) != 0
3358 && (i1_is_used
+ added_sets_1
+ (added_sets_2
&& i1_feeds_i2_n
)
3360 || (i0
!= 0 && FIND_REG_INC_NOTE (i0
, NULL_RTX
) != 0
3361 && (n_occurrences
+ added_sets_0
3362 + (added_sets_1
&& i0_feeds_i1_n
)
3363 + (added_sets_2
&& i0_feeds_i2_n
)
3365 /* Fail if we tried to make a new register. */
3366 || max_reg_num () != maxreg
3367 /* Fail if we couldn't do something and have a CLOBBER. */
3368 || GET_CODE (newpat
) == CLOBBER
3369 /* Fail if this new pattern is a MULT and we didn't have one before
3370 at the outer level. */
3371 || (GET_CODE (newpat
) == SET
&& GET_CODE (SET_SRC (newpat
)) == MULT
3378 /* If the actions of the earlier insns must be kept
3379 in addition to substituting them into the latest one,
3380 we must make a new PARALLEL for the latest insn
3381 to hold additional the SETs. */
3383 if (added_sets_0
|| added_sets_1
|| added_sets_2
)
3385 int extra_sets
= added_sets_0
+ added_sets_1
+ added_sets_2
;
3388 if (GET_CODE (newpat
) == PARALLEL
)
3390 rtvec old
= XVEC (newpat
, 0);
3391 total_sets
= XVECLEN (newpat
, 0) + extra_sets
;
3392 newpat
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (total_sets
));
3393 memcpy (XVEC (newpat
, 0)->elem
, &old
->elem
[0],
3394 sizeof (old
->elem
[0]) * old
->num_elem
);
3399 total_sets
= 1 + extra_sets
;
3400 newpat
= gen_rtx_PARALLEL (VOIDmode
, rtvec_alloc (total_sets
));
3401 XVECEXP (newpat
, 0, 0) = old
;
3405 XVECEXP (newpat
, 0, --total_sets
) = i0pat
;
3411 t
= subst (t
, i0dest
, i0src_copy
? i0src_copy
: i0src
, 0, 0, 0);
3413 XVECEXP (newpat
, 0, --total_sets
) = t
;
3419 t
= subst (t
, i1dest
, i1src_copy
? i1src_copy
: i1src
, 0, 0,
3420 i0_feeds_i1_n
&& i0dest_in_i0src
);
3421 if ((i0_feeds_i1_n
&& i1_feeds_i2_n
) || i0_feeds_i2_n
)
3422 t
= subst (t
, i0dest
, i0src_copy2
? i0src_copy2
: i0src
, 0, 0, 0);
3424 XVECEXP (newpat
, 0, --total_sets
) = t
;
3428 validate_replacement
:
3430 /* Note which hard regs this insn has as inputs. */
3431 mark_used_regs_combine (newpat
);
3433 /* If recog_for_combine fails, it strips existing clobbers. If we'll
3434 consider splitting this pattern, we might need these clobbers. */
3435 if (i1
&& GET_CODE (newpat
) == PARALLEL
3436 && GET_CODE (XVECEXP (newpat
, 0, XVECLEN (newpat
, 0) - 1)) == CLOBBER
)
3438 int len
= XVECLEN (newpat
, 0);
3440 newpat_vec_with_clobbers
= rtvec_alloc (len
);
3441 for (i
= 0; i
< len
; i
++)
3442 RTVEC_ELT (newpat_vec_with_clobbers
, i
) = XVECEXP (newpat
, 0, i
);
3445 /* We have recognized nothing yet. */
3446 insn_code_number
= -1;
3448 /* See if this is a PARALLEL of two SETs where one SET's destination is
3449 a register that is unused and this isn't marked as an instruction that
3450 might trap in an EH region. In that case, we just need the other SET.
3451 We prefer this over the PARALLEL.
3453 This can occur when simplifying a divmod insn. We *must* test for this
3454 case here because the code below that splits two independent SETs doesn't
3455 handle this case correctly when it updates the register status.
3457 It's pointless doing this if we originally had two sets, one from
3458 i3, and one from i2. Combining then splitting the parallel results
3459 in the original i2 again plus an invalid insn (which we delete).
3460 The net effect is only to move instructions around, which makes
3461 debug info less accurate. */
3463 if (!(added_sets_2
&& i1
== 0)
3464 && is_parallel_of_n_reg_sets (newpat
, 2)
3465 && asm_noperands (newpat
) < 0)
3467 rtx set0
= XVECEXP (newpat
, 0, 0);
3468 rtx set1
= XVECEXP (newpat
, 0, 1);
3469 rtx oldpat
= newpat
;
3471 if (((REG_P (SET_DEST (set1
))
3472 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (set1
)))
3473 || (GET_CODE (SET_DEST (set1
)) == SUBREG
3474 && find_reg_note (i3
, REG_UNUSED
, SUBREG_REG (SET_DEST (set1
)))))
3475 && insn_nothrow_p (i3
)
3476 && !side_effects_p (SET_SRC (set1
)))
3479 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3482 else if (((REG_P (SET_DEST (set0
))
3483 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (set0
)))
3484 || (GET_CODE (SET_DEST (set0
)) == SUBREG
3485 && find_reg_note (i3
, REG_UNUSED
,
3486 SUBREG_REG (SET_DEST (set0
)))))
3487 && insn_nothrow_p (i3
)
3488 && !side_effects_p (SET_SRC (set0
)))
3491 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3493 if (insn_code_number
>= 0)
3494 changed_i3_dest
= 1;
3497 if (insn_code_number
< 0)
3501 /* Is the result of combination a valid instruction? */
3502 if (insn_code_number
< 0)
3503 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3505 /* If we were combining three insns and the result is a simple SET
3506 with no ASM_OPERANDS that wasn't recognized, try to split it into two
3507 insns. There are two ways to do this. It can be split using a
3508 machine-specific method (like when you have an addition of a large
3509 constant) or by combine in the function find_split_point. */
3511 if (i1
&& insn_code_number
< 0 && GET_CODE (newpat
) == SET
3512 && asm_noperands (newpat
) < 0)
3514 rtx parallel
, *split
;
3515 rtx_insn
*m_split_insn
;
3517 /* See if the MD file can split NEWPAT. If it can't, see if letting it
3518 use I2DEST as a scratch register will help. In the latter case,
3519 convert I2DEST to the mode of the source of NEWPAT if we can. */
3521 m_split_insn
= combine_split_insns (newpat
, i3
);
3523 /* We can only use I2DEST as a scratch reg if it doesn't overlap any
3524 inputs of NEWPAT. */
3526 /* ??? If I2DEST is not safe, and I1DEST exists, then it would be
3527 possible to try that as a scratch reg. This would require adding
3528 more code to make it work though. */
3530 if (m_split_insn
== 0 && ! reg_overlap_mentioned_p (i2dest
, newpat
))
3532 machine_mode new_mode
= GET_MODE (SET_DEST (newpat
));
3534 /* First try to split using the original register as a
3535 scratch register. */
3536 parallel
= gen_rtx_PARALLEL (VOIDmode
,
3537 gen_rtvec (2, newpat
,
3538 gen_rtx_CLOBBER (VOIDmode
,
3540 m_split_insn
= combine_split_insns (parallel
, i3
);
3542 /* If that didn't work, try changing the mode of I2DEST if
3544 if (m_split_insn
== 0
3545 && new_mode
!= GET_MODE (i2dest
)
3546 && new_mode
!= VOIDmode
3547 && can_change_dest_mode (i2dest
, added_sets_2
, new_mode
))
3549 machine_mode old_mode
= GET_MODE (i2dest
);
3552 if (REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
)
3553 ni2dest
= gen_rtx_REG (new_mode
, REGNO (i2dest
));
3556 SUBST_MODE (regno_reg_rtx
[REGNO (i2dest
)], new_mode
);
3557 ni2dest
= regno_reg_rtx
[REGNO (i2dest
)];
3560 parallel
= (gen_rtx_PARALLEL
3562 gen_rtvec (2, newpat
,
3563 gen_rtx_CLOBBER (VOIDmode
,
3565 m_split_insn
= combine_split_insns (parallel
, i3
);
3567 if (m_split_insn
== 0
3568 && REGNO (i2dest
) >= FIRST_PSEUDO_REGISTER
)
3572 adjust_reg_mode (regno_reg_rtx
[REGNO (i2dest
)], old_mode
);
3573 buf
= undobuf
.undos
;
3574 undobuf
.undos
= buf
->next
;
3575 buf
->next
= undobuf
.frees
;
3576 undobuf
.frees
= buf
;
3580 i2scratch
= m_split_insn
!= 0;
3583 /* If recog_for_combine has discarded clobbers, try to use them
3584 again for the split. */
3585 if (m_split_insn
== 0 && newpat_vec_with_clobbers
)
3587 parallel
= gen_rtx_PARALLEL (VOIDmode
, newpat_vec_with_clobbers
);
3588 m_split_insn
= combine_split_insns (parallel
, i3
);
3591 if (m_split_insn
&& NEXT_INSN (m_split_insn
) == NULL_RTX
)
3593 rtx m_split_pat
= PATTERN (m_split_insn
);
3594 insn_code_number
= recog_for_combine (&m_split_pat
, i3
, &new_i3_notes
);
3595 if (insn_code_number
>= 0)
3596 newpat
= m_split_pat
;
3598 else if (m_split_insn
&& NEXT_INSN (NEXT_INSN (m_split_insn
)) == NULL_RTX
3599 && (next_nonnote_nondebug_insn (i2
) == i3
3600 || ! use_crosses_set_p (PATTERN (m_split_insn
), DF_INSN_LUID (i2
))))
3603 rtx newi3pat
= PATTERN (NEXT_INSN (m_split_insn
));
3604 newi2pat
= PATTERN (m_split_insn
);
3606 i3set
= single_set (NEXT_INSN (m_split_insn
));
3607 i2set
= single_set (m_split_insn
);
3609 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3611 /* If I2 or I3 has multiple SETs, we won't know how to track
3612 register status, so don't use these insns. If I2's destination
3613 is used between I2 and I3, we also can't use these insns. */
3615 if (i2_code_number
>= 0 && i2set
&& i3set
3616 && (next_nonnote_nondebug_insn (i2
) == i3
3617 || ! reg_used_between_p (SET_DEST (i2set
), i2
, i3
)))
3618 insn_code_number
= recog_for_combine (&newi3pat
, i3
,
3620 if (insn_code_number
>= 0)
3623 /* It is possible that both insns now set the destination of I3.
3624 If so, we must show an extra use of it. */
3626 if (insn_code_number
>= 0)
3628 rtx new_i3_dest
= SET_DEST (i3set
);
3629 rtx new_i2_dest
= SET_DEST (i2set
);
3631 while (GET_CODE (new_i3_dest
) == ZERO_EXTRACT
3632 || GET_CODE (new_i3_dest
) == STRICT_LOW_PART
3633 || GET_CODE (new_i3_dest
) == SUBREG
)
3634 new_i3_dest
= XEXP (new_i3_dest
, 0);
3636 while (GET_CODE (new_i2_dest
) == ZERO_EXTRACT
3637 || GET_CODE (new_i2_dest
) == STRICT_LOW_PART
3638 || GET_CODE (new_i2_dest
) == SUBREG
)
3639 new_i2_dest
= XEXP (new_i2_dest
, 0);
3641 if (REG_P (new_i3_dest
)
3642 && REG_P (new_i2_dest
)
3643 && REGNO (new_i3_dest
) == REGNO (new_i2_dest
)
3644 && REGNO (new_i2_dest
) < reg_n_sets_max
)
3645 INC_REG_N_SETS (REGNO (new_i2_dest
), 1);
3649 /* If we can split it and use I2DEST, go ahead and see if that
3650 helps things be recognized. Verify that none of the registers
3651 are set between I2 and I3. */
3652 if (insn_code_number
< 0
3653 && (split
= find_split_point (&newpat
, i3
, false)) != 0
3654 && (!HAVE_cc0
|| REG_P (i2dest
))
3655 /* We need I2DEST in the proper mode. If it is a hard register
3656 or the only use of a pseudo, we can change its mode.
3657 Make sure we don't change a hard register to have a mode that
3658 isn't valid for it, or change the number of registers. */
3659 && (GET_MODE (*split
) == GET_MODE (i2dest
)
3660 || GET_MODE (*split
) == VOIDmode
3661 || can_change_dest_mode (i2dest
, added_sets_2
,
3663 && (next_nonnote_nondebug_insn (i2
) == i3
3664 || ! use_crosses_set_p (*split
, DF_INSN_LUID (i2
)))
3665 /* We can't overwrite I2DEST if its value is still used by
3667 && ! reg_referenced_p (i2dest
, newpat
))
3669 rtx newdest
= i2dest
;
3670 enum rtx_code split_code
= GET_CODE (*split
);
3671 machine_mode split_mode
= GET_MODE (*split
);
3672 bool subst_done
= false;
3673 newi2pat
= NULL_RTX
;
3677 /* *SPLIT may be part of I2SRC, so make sure we have the
3678 original expression around for later debug processing.
3679 We should not need I2SRC any more in other cases. */
3680 if (MAY_HAVE_DEBUG_INSNS
)
3681 i2src
= copy_rtx (i2src
);
3685 /* Get NEWDEST as a register in the proper mode. We have already
3686 validated that we can do this. */
3687 if (GET_MODE (i2dest
) != split_mode
&& split_mode
!= VOIDmode
)
3689 if (REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
)
3690 newdest
= gen_rtx_REG (split_mode
, REGNO (i2dest
));
3693 SUBST_MODE (regno_reg_rtx
[REGNO (i2dest
)], split_mode
);
3694 newdest
= regno_reg_rtx
[REGNO (i2dest
)];
3698 /* If *SPLIT is a (mult FOO (const_int pow2)), convert it to
3699 an ASHIFT. This can occur if it was inside a PLUS and hence
3700 appeared to be a memory address. This is a kludge. */
3701 if (split_code
== MULT
3702 && CONST_INT_P (XEXP (*split
, 1))
3703 && INTVAL (XEXP (*split
, 1)) > 0
3704 && (i
= exact_log2 (UINTVAL (XEXP (*split
, 1)))) >= 0)
3706 SUBST (*split
, gen_rtx_ASHIFT (split_mode
,
3707 XEXP (*split
, 0), GEN_INT (i
)));
3708 /* Update split_code because we may not have a multiply
3710 split_code
= GET_CODE (*split
);
3713 /* Similarly for (plus (mult FOO (const_int pow2))). */
3714 if (split_code
== PLUS
3715 && GET_CODE (XEXP (*split
, 0)) == MULT
3716 && CONST_INT_P (XEXP (XEXP (*split
, 0), 1))
3717 && INTVAL (XEXP (XEXP (*split
, 0), 1)) > 0
3718 && (i
= exact_log2 (UINTVAL (XEXP (XEXP (*split
, 0), 1)))) >= 0)
3720 rtx nsplit
= XEXP (*split
, 0);
3721 SUBST (XEXP (*split
, 0), gen_rtx_ASHIFT (GET_MODE (nsplit
),
3722 XEXP (nsplit
, 0), GEN_INT (i
)));
3723 /* Update split_code because we may not have a multiply
3725 split_code
= GET_CODE (*split
);
3728 #ifdef INSN_SCHEDULING
3729 /* If *SPLIT is a paradoxical SUBREG, when we split it, it should
3730 be written as a ZERO_EXTEND. */
3731 if (split_code
== SUBREG
&& MEM_P (SUBREG_REG (*split
)))
3733 /* Or as a SIGN_EXTEND if LOAD_EXTEND_OP says that that's
3734 what it really is. */
3735 if (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (*split
)))
3737 SUBST (*split
, gen_rtx_SIGN_EXTEND (split_mode
,
3738 SUBREG_REG (*split
)));
3740 SUBST (*split
, gen_rtx_ZERO_EXTEND (split_mode
,
3741 SUBREG_REG (*split
)));
3745 /* Attempt to split binary operators using arithmetic identities. */
3746 if (BINARY_P (SET_SRC (newpat
))
3747 && split_mode
== GET_MODE (SET_SRC (newpat
))
3748 && ! side_effects_p (SET_SRC (newpat
)))
3750 rtx setsrc
= SET_SRC (newpat
);
3751 machine_mode mode
= GET_MODE (setsrc
);
3752 enum rtx_code code
= GET_CODE (setsrc
);
3753 rtx src_op0
= XEXP (setsrc
, 0);
3754 rtx src_op1
= XEXP (setsrc
, 1);
3756 /* Split "X = Y op Y" as "Z = Y; X = Z op Z". */
3757 if (rtx_equal_p (src_op0
, src_op1
))
3759 newi2pat
= gen_rtx_SET (newdest
, src_op0
);
3760 SUBST (XEXP (setsrc
, 0), newdest
);
3761 SUBST (XEXP (setsrc
, 1), newdest
);
3764 /* Split "((P op Q) op R) op S" where op is PLUS or MULT. */
3765 else if ((code
== PLUS
|| code
== MULT
)
3766 && GET_CODE (src_op0
) == code
3767 && GET_CODE (XEXP (src_op0
, 0)) == code
3768 && (INTEGRAL_MODE_P (mode
)
3769 || (FLOAT_MODE_P (mode
)
3770 && flag_unsafe_math_optimizations
)))
3772 rtx p
= XEXP (XEXP (src_op0
, 0), 0);
3773 rtx q
= XEXP (XEXP (src_op0
, 0), 1);
3774 rtx r
= XEXP (src_op0
, 1);
3777 /* Split both "((X op Y) op X) op Y" and
3778 "((X op Y) op Y) op X" as "T op T" where T is
3780 if ((rtx_equal_p (p
,r
) && rtx_equal_p (q
,s
))
3781 || (rtx_equal_p (p
,s
) && rtx_equal_p (q
,r
)))
3783 newi2pat
= gen_rtx_SET (newdest
, XEXP (src_op0
, 0));
3784 SUBST (XEXP (setsrc
, 0), newdest
);
3785 SUBST (XEXP (setsrc
, 1), newdest
);
3788 /* Split "((X op X) op Y) op Y)" as "T op T" where
3790 else if (rtx_equal_p (p
,q
) && rtx_equal_p (r
,s
))
3792 rtx tmp
= simplify_gen_binary (code
, mode
, p
, r
);
3793 newi2pat
= gen_rtx_SET (newdest
, tmp
);
3794 SUBST (XEXP (setsrc
, 0), newdest
);
3795 SUBST (XEXP (setsrc
, 1), newdest
);
3803 newi2pat
= gen_rtx_SET (newdest
, *split
);
3804 SUBST (*split
, newdest
);
3807 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3809 /* recog_for_combine might have added CLOBBERs to newi2pat.
3810 Make sure NEWPAT does not depend on the clobbered regs. */
3811 if (GET_CODE (newi2pat
) == PARALLEL
)
3812 for (i
= XVECLEN (newi2pat
, 0) - 1; i
>= 0; i
--)
3813 if (GET_CODE (XVECEXP (newi2pat
, 0, i
)) == CLOBBER
)
3815 rtx reg
= XEXP (XVECEXP (newi2pat
, 0, i
), 0);
3816 if (reg_overlap_mentioned_p (reg
, newpat
))
3823 /* If the split point was a MULT and we didn't have one before,
3824 don't use one now. */
3825 if (i2_code_number
>= 0 && ! (split_code
== MULT
&& ! have_mult
))
3826 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3830 /* Check for a case where we loaded from memory in a narrow mode and
3831 then sign extended it, but we need both registers. In that case,
3832 we have a PARALLEL with both loads from the same memory location.
3833 We can split this into a load from memory followed by a register-register
3834 copy. This saves at least one insn, more if register allocation can
3837 We cannot do this if the destination of the first assignment is a
3838 condition code register or cc0. We eliminate this case by making sure
3839 the SET_DEST and SET_SRC have the same mode.
3841 We cannot do this if the destination of the second assignment is
3842 a register that we have already assumed is zero-extended. Similarly
3843 for a SUBREG of such a register. */
3845 else if (i1
&& insn_code_number
< 0 && asm_noperands (newpat
) < 0
3846 && GET_CODE (newpat
) == PARALLEL
3847 && XVECLEN (newpat
, 0) == 2
3848 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
3849 && GET_CODE (SET_SRC (XVECEXP (newpat
, 0, 0))) == SIGN_EXTEND
3850 && (GET_MODE (SET_DEST (XVECEXP (newpat
, 0, 0)))
3851 == GET_MODE (SET_SRC (XVECEXP (newpat
, 0, 0))))
3852 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
3853 && rtx_equal_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
3854 XEXP (SET_SRC (XVECEXP (newpat
, 0, 0)), 0))
3855 && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
3857 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
3858 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
3859 && ! (temp_expr
= SET_DEST (XVECEXP (newpat
, 0, 1)),
3861 && reg_stat
[REGNO (temp_expr
)].nonzero_bits
!= 0
3862 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < BITS_PER_WORD
3863 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < HOST_BITS_PER_INT
3864 && (reg_stat
[REGNO (temp_expr
)].nonzero_bits
3865 != GET_MODE_MASK (word_mode
))))
3866 && ! (GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) == SUBREG
3867 && (temp_expr
= SUBREG_REG (SET_DEST (XVECEXP (newpat
, 0, 1))),
3869 && reg_stat
[REGNO (temp_expr
)].nonzero_bits
!= 0
3870 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < BITS_PER_WORD
3871 && GET_MODE_PRECISION (GET_MODE (temp_expr
)) < HOST_BITS_PER_INT
3872 && (reg_stat
[REGNO (temp_expr
)].nonzero_bits
3873 != GET_MODE_MASK (word_mode
)))))
3874 && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
3875 SET_SRC (XVECEXP (newpat
, 0, 1)))
3876 && ! find_reg_note (i3
, REG_UNUSED
,
3877 SET_DEST (XVECEXP (newpat
, 0, 0))))
3881 newi2pat
= XVECEXP (newpat
, 0, 0);
3882 ni2dest
= SET_DEST (XVECEXP (newpat
, 0, 0));
3883 newpat
= XVECEXP (newpat
, 0, 1);
3884 SUBST (SET_SRC (newpat
),
3885 gen_lowpart (GET_MODE (SET_SRC (newpat
)), ni2dest
));
3886 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3888 if (i2_code_number
>= 0)
3889 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3891 if (insn_code_number
>= 0)
3895 /* Similarly, check for a case where we have a PARALLEL of two independent
3896 SETs but we started with three insns. In this case, we can do the sets
3897 as two separate insns. This case occurs when some SET allows two
3898 other insns to combine, but the destination of that SET is still live.
3900 Also do this if we started with two insns and (at least) one of the
3901 resulting sets is a noop; this noop will be deleted later. */
3903 else if (insn_code_number
< 0 && asm_noperands (newpat
) < 0
3904 && GET_CODE (newpat
) == PARALLEL
3905 && XVECLEN (newpat
, 0) == 2
3906 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
3907 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
3908 && (i1
|| set_noop_p (XVECEXP (newpat
, 0, 0))
3909 || set_noop_p (XVECEXP (newpat
, 0, 1)))
3910 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != ZERO_EXTRACT
3911 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != STRICT_LOW_PART
3912 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
3913 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
3914 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
3915 XVECEXP (newpat
, 0, 0))
3916 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 0)),
3917 XVECEXP (newpat
, 0, 1))
3918 && ! (contains_muldiv (SET_SRC (XVECEXP (newpat
, 0, 0)))
3919 && contains_muldiv (SET_SRC (XVECEXP (newpat
, 0, 1)))))
3921 rtx set0
= XVECEXP (newpat
, 0, 0);
3922 rtx set1
= XVECEXP (newpat
, 0, 1);
3924 /* Normally, it doesn't matter which of the two is done first,
3925 but the one that references cc0 can't be the second, and
3926 one which uses any regs/memory set in between i2 and i3 can't
3927 be first. The PARALLEL might also have been pre-existing in i3,
3928 so we need to make sure that we won't wrongly hoist a SET to i2
3929 that would conflict with a death note present in there. */
3930 if (!use_crosses_set_p (SET_SRC (set1
), DF_INSN_LUID (i2
))
3931 && !(REG_P (SET_DEST (set1
))
3932 && find_reg_note (i2
, REG_DEAD
, SET_DEST (set1
)))
3933 && !(GET_CODE (SET_DEST (set1
)) == SUBREG
3934 && find_reg_note (i2
, REG_DEAD
,
3935 SUBREG_REG (SET_DEST (set1
))))
3936 && (!HAVE_cc0
|| !reg_referenced_p (cc0_rtx
, set0
))
3937 /* If I3 is a jump, ensure that set0 is a jump so that
3938 we do not create invalid RTL. */
3939 && (!JUMP_P (i3
) || SET_DEST (set0
) == pc_rtx
)
3945 else if (!use_crosses_set_p (SET_SRC (set0
), DF_INSN_LUID (i2
))
3946 && !(REG_P (SET_DEST (set0
))
3947 && find_reg_note (i2
, REG_DEAD
, SET_DEST (set0
)))
3948 && !(GET_CODE (SET_DEST (set0
)) == SUBREG
3949 && find_reg_note (i2
, REG_DEAD
,
3950 SUBREG_REG (SET_DEST (set0
))))
3951 && (!HAVE_cc0
|| !reg_referenced_p (cc0_rtx
, set1
))
3952 /* If I3 is a jump, ensure that set1 is a jump so that
3953 we do not create invalid RTL. */
3954 && (!JUMP_P (i3
) || SET_DEST (set1
) == pc_rtx
)
3966 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
);
3968 if (i2_code_number
>= 0)
3970 /* recog_for_combine might have added CLOBBERs to newi2pat.
3971 Make sure NEWPAT does not depend on the clobbered regs. */
3972 if (GET_CODE (newi2pat
) == PARALLEL
)
3974 for (i
= XVECLEN (newi2pat
, 0) - 1; i
>= 0; i
--)
3975 if (GET_CODE (XVECEXP (newi2pat
, 0, i
)) == CLOBBER
)
3977 rtx reg
= XEXP (XVECEXP (newi2pat
, 0, i
), 0);
3978 if (reg_overlap_mentioned_p (reg
, newpat
))
3986 insn_code_number
= recog_for_combine (&newpat
, i3
, &new_i3_notes
);
3990 /* If it still isn't recognized, fail and change things back the way they
3992 if ((insn_code_number
< 0
3993 /* Is the result a reasonable ASM_OPERANDS? */
3994 && (! check_asm_operands (newpat
) || added_sets_1
|| added_sets_2
)))
4000 /* If we had to change another insn, make sure it is valid also. */
4001 if (undobuf
.other_insn
)
4003 CLEAR_HARD_REG_SET (newpat_used_regs
);
4005 other_pat
= PATTERN (undobuf
.other_insn
);
4006 other_code_number
= recog_for_combine (&other_pat
, undobuf
.other_insn
,
4009 if (other_code_number
< 0 && ! check_asm_operands (other_pat
))
4016 /* If I2 is the CC0 setter and I3 is the CC0 user then check whether
4017 they are adjacent to each other or not. */
4020 rtx_insn
*p
= prev_nonnote_insn (i3
);
4021 if (p
&& p
!= i2
&& NONJUMP_INSN_P (p
) && newi2pat
4022 && sets_cc0_p (newi2pat
))
4029 /* Only allow this combination if insn_rtx_costs reports that the
4030 replacement instructions are cheaper than the originals. */
4031 if (!combine_validate_cost (i0
, i1
, i2
, i3
, newpat
, newi2pat
, other_pat
))
4037 if (MAY_HAVE_DEBUG_INSNS
)
4041 for (undo
= undobuf
.undos
; undo
; undo
= undo
->next
)
4042 if (undo
->kind
== UNDO_MODE
)
4044 rtx reg
= *undo
->where
.r
;
4045 machine_mode new_mode
= GET_MODE (reg
);
4046 machine_mode old_mode
= undo
->old_contents
.m
;
4048 /* Temporarily revert mode back. */
4049 adjust_reg_mode (reg
, old_mode
);
4051 if (reg
== i2dest
&& i2scratch
)
4053 /* If we used i2dest as a scratch register with a
4054 different mode, substitute it for the original
4055 i2src while its original mode is temporarily
4056 restored, and then clear i2scratch so that we don't
4057 do it again later. */
4058 propagate_for_debug (i2
, last_combined_insn
, reg
, i2src
,
4061 /* Put back the new mode. */
4062 adjust_reg_mode (reg
, new_mode
);
4066 rtx tempreg
= gen_raw_REG (old_mode
, REGNO (reg
));
4067 rtx_insn
*first
, *last
;
4072 last
= last_combined_insn
;
4077 last
= undobuf
.other_insn
;
4079 if (DF_INSN_LUID (last
)
4080 < DF_INSN_LUID (last_combined_insn
))
4081 last
= last_combined_insn
;
4084 /* We're dealing with a reg that changed mode but not
4085 meaning, so we want to turn it into a subreg for
4086 the new mode. However, because of REG sharing and
4087 because its mode had already changed, we have to do
4088 it in two steps. First, replace any debug uses of
4089 reg, with its original mode temporarily restored,
4090 with this copy we have created; then, replace the
4091 copy with the SUBREG of the original shared reg,
4092 once again changed to the new mode. */
4093 propagate_for_debug (first
, last
, reg
, tempreg
,
4095 adjust_reg_mode (reg
, new_mode
);
4096 propagate_for_debug (first
, last
, tempreg
,
4097 lowpart_subreg (old_mode
, reg
, new_mode
),
4103 /* If we will be able to accept this, we have made a
4104 change to the destination of I3. This requires us to
4105 do a few adjustments. */
4107 if (changed_i3_dest
)
4109 PATTERN (i3
) = newpat
;
4110 adjust_for_new_dest (i3
);
4113 /* We now know that we can do this combination. Merge the insns and
4114 update the status of registers and LOG_LINKS. */
4116 if (undobuf
.other_insn
)
4120 PATTERN (undobuf
.other_insn
) = other_pat
;
4122 /* If any of the notes in OTHER_INSN were REG_DEAD or REG_UNUSED,
4123 ensure that they are still valid. Then add any non-duplicate
4124 notes added by recog_for_combine. */
4125 for (note
= REG_NOTES (undobuf
.other_insn
); note
; note
= next
)
4127 next
= XEXP (note
, 1);
4129 if ((REG_NOTE_KIND (note
) == REG_DEAD
4130 && !reg_referenced_p (XEXP (note
, 0),
4131 PATTERN (undobuf
.other_insn
)))
4132 ||(REG_NOTE_KIND (note
) == REG_UNUSED
4133 && !reg_set_p (XEXP (note
, 0),
4134 PATTERN (undobuf
.other_insn
))))
4135 remove_note (undobuf
.other_insn
, note
);
4138 distribute_notes (new_other_notes
, undobuf
.other_insn
,
4139 undobuf
.other_insn
, NULL
, NULL_RTX
, NULL_RTX
,
4146 struct insn_link
*link
;
4149 /* I3 now uses what used to be its destination and which is now
4150 I2's destination. This requires us to do a few adjustments. */
4151 PATTERN (i3
) = newpat
;
4152 adjust_for_new_dest (i3
);
4154 /* We need a LOG_LINK from I3 to I2. But we used to have one,
4157 However, some later insn might be using I2's dest and have
4158 a LOG_LINK pointing at I3. We must remove this link.
4159 The simplest way to remove the link is to point it at I1,
4160 which we know will be a NOTE. */
4162 /* newi2pat is usually a SET here; however, recog_for_combine might
4163 have added some clobbers. */
4164 if (GET_CODE (newi2pat
) == PARALLEL
)
4165 ni2dest
= SET_DEST (XVECEXP (newi2pat
, 0, 0));
4167 ni2dest
= SET_DEST (newi2pat
);
4169 for (insn
= NEXT_INSN (i3
);
4170 insn
&& (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
4171 || insn
!= BB_HEAD (this_basic_block
->next_bb
));
4172 insn
= NEXT_INSN (insn
))
4174 if (INSN_P (insn
) && reg_referenced_p (ni2dest
, PATTERN (insn
)))
4176 FOR_EACH_LOG_LINK (link
, insn
)
4177 if (link
->insn
== i3
)
4186 rtx i3notes
, i2notes
, i1notes
= 0, i0notes
= 0;
4187 struct insn_link
*i3links
, *i2links
, *i1links
= 0, *i0links
= 0;
4190 /* Compute which registers we expect to eliminate. newi2pat may be setting
4191 either i3dest or i2dest, so we must check it. */
4192 rtx elim_i2
= ((newi2pat
&& reg_set_p (i2dest
, newi2pat
))
4193 || i2dest_in_i2src
|| i2dest_in_i1src
|| i2dest_in_i0src
4196 /* For i1, we need to compute both local elimination and global
4197 elimination information with respect to newi2pat because i1dest
4198 may be the same as i3dest, in which case newi2pat may be setting
4199 i1dest. Global information is used when distributing REG_DEAD
4200 note for i2 and i3, in which case it does matter if newi2pat sets
4203 Local information is used when distributing REG_DEAD note for i1,
4204 in which case it doesn't matter if newi2pat sets i1dest or not.
4205 See PR62151, if we have four insns combination:
4207 i1: r1 <- i1src (using r0)
4209 i2: r0 <- i2src (using r1)
4210 i3: r3 <- i3src (using r0)
4212 From i1's point of view, r0 is eliminated, no matter if it is set
4213 by newi2pat or not. In other words, REG_DEAD info for r0 in i1
4214 should be discarded.
4216 Note local information only affects cases in forms like "I1->I2->I3",
4217 "I0->I1->I2->I3" or "I0&I1->I2, I2->I3". For other cases like
4218 "I0->I1, I1&I2->I3" or "I1&I2->I3", newi2pat won't set i1dest or
4220 rtx local_elim_i1
= (i1
== 0 || i1dest_in_i1src
|| i1dest_in_i0src
4223 rtx elim_i1
= (local_elim_i1
== 0
4224 || (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
4226 /* Same case as i1. */
4227 rtx local_elim_i0
= (i0
== 0 || i0dest_in_i0src
|| !i0dest_killed
4229 rtx elim_i0
= (local_elim_i0
== 0
4230 || (newi2pat
&& reg_set_p (i0dest
, newi2pat
))
4233 /* Get the old REG_NOTES and LOG_LINKS from all our insns and
4235 i3notes
= REG_NOTES (i3
), i3links
= LOG_LINKS (i3
);
4236 i2notes
= REG_NOTES (i2
), i2links
= LOG_LINKS (i2
);
4238 i1notes
= REG_NOTES (i1
), i1links
= LOG_LINKS (i1
);
4240 i0notes
= REG_NOTES (i0
), i0links
= LOG_LINKS (i0
);
4242 /* Ensure that we do not have something that should not be shared but
4243 occurs multiple times in the new insns. Check this by first
4244 resetting all the `used' flags and then copying anything is shared. */
4246 reset_used_flags (i3notes
);
4247 reset_used_flags (i2notes
);
4248 reset_used_flags (i1notes
);
4249 reset_used_flags (i0notes
);
4250 reset_used_flags (newpat
);
4251 reset_used_flags (newi2pat
);
4252 if (undobuf
.other_insn
)
4253 reset_used_flags (PATTERN (undobuf
.other_insn
));
4255 i3notes
= copy_rtx_if_shared (i3notes
);
4256 i2notes
= copy_rtx_if_shared (i2notes
);
4257 i1notes
= copy_rtx_if_shared (i1notes
);
4258 i0notes
= copy_rtx_if_shared (i0notes
);
4259 newpat
= copy_rtx_if_shared (newpat
);
4260 newi2pat
= copy_rtx_if_shared (newi2pat
);
4261 if (undobuf
.other_insn
)
4262 reset_used_flags (PATTERN (undobuf
.other_insn
));
4264 INSN_CODE (i3
) = insn_code_number
;
4265 PATTERN (i3
) = newpat
;
4267 if (CALL_P (i3
) && CALL_INSN_FUNCTION_USAGE (i3
))
4269 rtx call_usage
= CALL_INSN_FUNCTION_USAGE (i3
);
4271 reset_used_flags (call_usage
);
4272 call_usage
= copy_rtx (call_usage
);
4276 /* I2SRC must still be meaningful at this point. Some splitting
4277 operations can invalidate I2SRC, but those operations do not
4280 replace_rtx (call_usage
, i2dest
, i2src
);
4284 replace_rtx (call_usage
, i1dest
, i1src
);
4286 replace_rtx (call_usage
, i0dest
, i0src
);
4288 CALL_INSN_FUNCTION_USAGE (i3
) = call_usage
;
4291 if (undobuf
.other_insn
)
4292 INSN_CODE (undobuf
.other_insn
) = other_code_number
;
4294 /* We had one special case above where I2 had more than one set and
4295 we replaced a destination of one of those sets with the destination
4296 of I3. In that case, we have to update LOG_LINKS of insns later
4297 in this basic block. Note that this (expensive) case is rare.
4299 Also, in this case, we must pretend that all REG_NOTEs for I2
4300 actually came from I3, so that REG_UNUSED notes from I2 will be
4301 properly handled. */
4303 if (i3_subst_into_i2
)
4305 for (i
= 0; i
< XVECLEN (PATTERN (i2
), 0); i
++)
4306 if ((GET_CODE (XVECEXP (PATTERN (i2
), 0, i
)) == SET
4307 || GET_CODE (XVECEXP (PATTERN (i2
), 0, i
)) == CLOBBER
)
4308 && REG_P (SET_DEST (XVECEXP (PATTERN (i2
), 0, i
)))
4309 && SET_DEST (XVECEXP (PATTERN (i2
), 0, i
)) != i2dest
4310 && ! find_reg_note (i2
, REG_UNUSED
,
4311 SET_DEST (XVECEXP (PATTERN (i2
), 0, i
))))
4312 for (temp_insn
= NEXT_INSN (i2
);
4314 && (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
4315 || BB_HEAD (this_basic_block
) != temp_insn
);
4316 temp_insn
= NEXT_INSN (temp_insn
))
4317 if (temp_insn
!= i3
&& INSN_P (temp_insn
))
4318 FOR_EACH_LOG_LINK (link
, temp_insn
)
4319 if (link
->insn
== i2
)
4325 while (XEXP (link
, 1))
4326 link
= XEXP (link
, 1);
4327 XEXP (link
, 1) = i2notes
;
4334 LOG_LINKS (i3
) = NULL
;
4336 LOG_LINKS (i2
) = NULL
;
4341 if (MAY_HAVE_DEBUG_INSNS
&& i2scratch
)
4342 propagate_for_debug (i2
, last_combined_insn
, i2dest
, i2src
,
4344 INSN_CODE (i2
) = i2_code_number
;
4345 PATTERN (i2
) = newi2pat
;
4349 if (MAY_HAVE_DEBUG_INSNS
&& i2src
)
4350 propagate_for_debug (i2
, last_combined_insn
, i2dest
, i2src
,
4352 SET_INSN_DELETED (i2
);
4357 LOG_LINKS (i1
) = NULL
;
4359 if (MAY_HAVE_DEBUG_INSNS
)
4360 propagate_for_debug (i1
, last_combined_insn
, i1dest
, i1src
,
4362 SET_INSN_DELETED (i1
);
4367 LOG_LINKS (i0
) = NULL
;
4369 if (MAY_HAVE_DEBUG_INSNS
)
4370 propagate_for_debug (i0
, last_combined_insn
, i0dest
, i0src
,
4372 SET_INSN_DELETED (i0
);
4375 /* Get death notes for everything that is now used in either I3 or
4376 I2 and used to die in a previous insn. If we built two new
4377 patterns, move from I1 to I2 then I2 to I3 so that we get the
4378 proper movement on registers that I2 modifies. */
4381 from_luid
= DF_INSN_LUID (i0
);
4383 from_luid
= DF_INSN_LUID (i1
);
4385 from_luid
= DF_INSN_LUID (i2
);
4387 move_deaths (newi2pat
, NULL_RTX
, from_luid
, i2
, &midnotes
);
4388 move_deaths (newpat
, newi2pat
, from_luid
, i3
, &midnotes
);
4390 /* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */
4392 distribute_notes (i3notes
, i3
, i3
, newi2pat
? i2
: NULL
,
4393 elim_i2
, elim_i1
, elim_i0
);
4395 distribute_notes (i2notes
, i2
, i3
, newi2pat
? i2
: NULL
,
4396 elim_i2
, elim_i1
, elim_i0
);
4398 distribute_notes (i1notes
, i1
, i3
, newi2pat
? i2
: NULL
,
4399 elim_i2
, local_elim_i1
, local_elim_i0
);
4401 distribute_notes (i0notes
, i0
, i3
, newi2pat
? i2
: NULL
,
4402 elim_i2
, elim_i1
, local_elim_i0
);
4404 distribute_notes (midnotes
, NULL
, i3
, newi2pat
? i2
: NULL
,
4405 elim_i2
, elim_i1
, elim_i0
);
4407 /* Distribute any notes added to I2 or I3 by recog_for_combine. We
4408 know these are REG_UNUSED and want them to go to the desired insn,
4409 so we always pass it as i3. */
4411 if (newi2pat
&& new_i2_notes
)
4412 distribute_notes (new_i2_notes
, i2
, i2
, NULL
, NULL_RTX
, NULL_RTX
,
4416 distribute_notes (new_i3_notes
, i3
, i3
, NULL
, NULL_RTX
, NULL_RTX
,
4419 /* If I3DEST was used in I3SRC, it really died in I3. We may need to
4420 put a REG_DEAD note for it somewhere. If NEWI2PAT exists and sets
4421 I3DEST, the death must be somewhere before I2, not I3. If we passed I3
4422 in that case, it might delete I2. Similarly for I2 and I1.
4423 Show an additional death due to the REG_DEAD note we make here. If
4424 we discard it in distribute_notes, we will decrement it again. */
4428 rtx new_note
= alloc_reg_note (REG_DEAD
, i3dest_killed
, NULL_RTX
);
4429 if (newi2pat
&& reg_set_p (i3dest_killed
, newi2pat
))
4430 distribute_notes (new_note
, NULL
, i2
, NULL
, elim_i2
,
4433 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4434 elim_i2
, elim_i1
, elim_i0
);
4437 if (i2dest_in_i2src
)
4439 rtx new_note
= alloc_reg_note (REG_DEAD
, i2dest
, NULL_RTX
);
4440 if (newi2pat
&& reg_set_p (i2dest
, newi2pat
))
4441 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4442 NULL_RTX
, NULL_RTX
);
4444 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4445 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4448 if (i1dest_in_i1src
)
4450 rtx new_note
= alloc_reg_note (REG_DEAD
, i1dest
, NULL_RTX
);
4451 if (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
4452 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4453 NULL_RTX
, NULL_RTX
);
4455 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4456 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4459 if (i0dest_in_i0src
)
4461 rtx new_note
= alloc_reg_note (REG_DEAD
, i0dest
, NULL_RTX
);
4462 if (newi2pat
&& reg_set_p (i0dest
, newi2pat
))
4463 distribute_notes (new_note
, NULL
, i2
, NULL
, NULL_RTX
,
4464 NULL_RTX
, NULL_RTX
);
4466 distribute_notes (new_note
, NULL
, i3
, newi2pat
? i2
: NULL
,
4467 NULL_RTX
, NULL_RTX
, NULL_RTX
);
4470 distribute_links (i3links
);
4471 distribute_links (i2links
);
4472 distribute_links (i1links
);
4473 distribute_links (i0links
);
4477 struct insn_link
*link
;
4478 rtx_insn
*i2_insn
= 0;
4479 rtx i2_val
= 0, set
;
4481 /* The insn that used to set this register doesn't exist, and
4482 this life of the register may not exist either. See if one of
4483 I3's links points to an insn that sets I2DEST. If it does,
4484 that is now the last known value for I2DEST. If we don't update
4485 this and I2 set the register to a value that depended on its old
4486 contents, we will get confused. If this insn is used, thing
4487 will be set correctly in combine_instructions. */
4488 FOR_EACH_LOG_LINK (link
, i3
)
4489 if ((set
= single_set (link
->insn
)) != 0
4490 && rtx_equal_p (i2dest
, SET_DEST (set
)))
4491 i2_insn
= link
->insn
, i2_val
= SET_SRC (set
);
4493 record_value_for_reg (i2dest
, i2_insn
, i2_val
);
4495 /* If the reg formerly set in I2 died only once and that was in I3,
4496 zero its use count so it won't make `reload' do any work. */
4498 && (newi2pat
== 0 || ! reg_mentioned_p (i2dest
, newi2pat
))
4499 && ! i2dest_in_i2src
4500 && REGNO (i2dest
) < reg_n_sets_max
)
4501 INC_REG_N_SETS (REGNO (i2dest
), -1);
4504 if (i1
&& REG_P (i1dest
))
4506 struct insn_link
*link
;
4507 rtx_insn
*i1_insn
= 0;
4508 rtx i1_val
= 0, set
;
4510 FOR_EACH_LOG_LINK (link
, i3
)
4511 if ((set
= single_set (link
->insn
)) != 0
4512 && rtx_equal_p (i1dest
, SET_DEST (set
)))
4513 i1_insn
= link
->insn
, i1_val
= SET_SRC (set
);
4515 record_value_for_reg (i1dest
, i1_insn
, i1_val
);
4518 && ! i1dest_in_i1src
4519 && REGNO (i1dest
) < reg_n_sets_max
)
4520 INC_REG_N_SETS (REGNO (i1dest
), -1);
4523 if (i0
&& REG_P (i0dest
))
4525 struct insn_link
*link
;
4526 rtx_insn
*i0_insn
= 0;
4527 rtx i0_val
= 0, set
;
4529 FOR_EACH_LOG_LINK (link
, i3
)
4530 if ((set
= single_set (link
->insn
)) != 0
4531 && rtx_equal_p (i0dest
, SET_DEST (set
)))
4532 i0_insn
= link
->insn
, i0_val
= SET_SRC (set
);
4534 record_value_for_reg (i0dest
, i0_insn
, i0_val
);
4537 && ! i0dest_in_i0src
4538 && REGNO (i0dest
) < reg_n_sets_max
)
4539 INC_REG_N_SETS (REGNO (i0dest
), -1);
4542 /* Update reg_stat[].nonzero_bits et al for any changes that may have
4543 been made to this insn. The order is important, because newi2pat
4544 can affect nonzero_bits of newpat. */
4546 note_stores (newi2pat
, set_nonzero_bits_and_sign_copies
, NULL
);
4547 note_stores (newpat
, set_nonzero_bits_and_sign_copies
, NULL
);
4550 if (undobuf
.other_insn
!= NULL_RTX
)
4554 fprintf (dump_file
, "modifying other_insn ");
4555 dump_insn_slim (dump_file
, undobuf
.other_insn
);
4557 df_insn_rescan (undobuf
.other_insn
);
4560 if (i0
&& !(NOTE_P (i0
) && (NOTE_KIND (i0
) == NOTE_INSN_DELETED
)))
4564 fprintf (dump_file
, "modifying insn i0 ");
4565 dump_insn_slim (dump_file
, i0
);
4567 df_insn_rescan (i0
);
4570 if (i1
&& !(NOTE_P (i1
) && (NOTE_KIND (i1
) == NOTE_INSN_DELETED
)))
4574 fprintf (dump_file
, "modifying insn i1 ");
4575 dump_insn_slim (dump_file
, i1
);
4577 df_insn_rescan (i1
);
4580 if (i2
&& !(NOTE_P (i2
) && (NOTE_KIND (i2
) == NOTE_INSN_DELETED
)))
4584 fprintf (dump_file
, "modifying insn i2 ");
4585 dump_insn_slim (dump_file
, i2
);
4587 df_insn_rescan (i2
);
4590 if (i3
&& !(NOTE_P (i3
) && (NOTE_KIND (i3
) == NOTE_INSN_DELETED
)))
4594 fprintf (dump_file
, "modifying insn i3 ");
4595 dump_insn_slim (dump_file
, i3
);
4597 df_insn_rescan (i3
);
4600 /* Set new_direct_jump_p if a new return or simple jump instruction
4601 has been created. Adjust the CFG accordingly. */
4602 if (returnjump_p (i3
) || any_uncondjump_p (i3
))
4604 *new_direct_jump_p
= 1;
4605 mark_jump_label (PATTERN (i3
), i3
, 0);
4606 update_cfg_for_uncondjump (i3
);
4609 if (undobuf
.other_insn
!= NULL_RTX
4610 && (returnjump_p (undobuf
.other_insn
)
4611 || any_uncondjump_p (undobuf
.other_insn
)))
4613 *new_direct_jump_p
= 1;
4614 update_cfg_for_uncondjump (undobuf
.other_insn
);
4617 /* A noop might also need cleaning up of CFG, if it comes from the
4618 simplification of a jump. */
4620 && GET_CODE (newpat
) == SET
4621 && SET_SRC (newpat
) == pc_rtx
4622 && SET_DEST (newpat
) == pc_rtx
)
4624 *new_direct_jump_p
= 1;
4625 update_cfg_for_uncondjump (i3
);
4628 if (undobuf
.other_insn
!= NULL_RTX
4629 && JUMP_P (undobuf
.other_insn
)
4630 && GET_CODE (PATTERN (undobuf
.other_insn
)) == SET
4631 && SET_SRC (PATTERN (undobuf
.other_insn
)) == pc_rtx
4632 && SET_DEST (PATTERN (undobuf
.other_insn
)) == pc_rtx
)
4634 *new_direct_jump_p
= 1;
4635 update_cfg_for_uncondjump (undobuf
.other_insn
);
4638 combine_successes
++;
4641 if (added_links_insn
4642 && (newi2pat
== 0 || DF_INSN_LUID (added_links_insn
) < DF_INSN_LUID (i2
))
4643 && DF_INSN_LUID (added_links_insn
) < DF_INSN_LUID (i3
))
4644 return added_links_insn
;
4646 return newi2pat
? i2
: i3
;
4649 /* Get a marker for undoing to the current state. */
4652 get_undo_marker (void)
4654 return undobuf
.undos
;
4657 /* Undo the modifications up to the marker. */
4660 undo_to_marker (void *marker
)
4662 struct undo
*undo
, *next
;
4664 for (undo
= undobuf
.undos
; undo
!= marker
; undo
= next
)
4672 *undo
->where
.r
= undo
->old_contents
.r
;
4675 *undo
->where
.i
= undo
->old_contents
.i
;
4678 adjust_reg_mode (*undo
->where
.r
, undo
->old_contents
.m
);
4681 *undo
->where
.l
= undo
->old_contents
.l
;
4687 undo
->next
= undobuf
.frees
;
4688 undobuf
.frees
= undo
;
4691 undobuf
.undos
= (struct undo
*) marker
;
4694 /* Undo all the modifications recorded in undobuf. */
4702 /* We've committed to accepting the changes we made. Move all
4703 of the undos to the free list. */
4708 struct undo
*undo
, *next
;
4710 for (undo
= undobuf
.undos
; undo
; undo
= next
)
4713 undo
->next
= undobuf
.frees
;
4714 undobuf
.frees
= undo
;
4719 /* Find the innermost point within the rtx at LOC, possibly LOC itself,
4720 where we have an arithmetic expression and return that point. LOC will
4723 try_combine will call this function to see if an insn can be split into
4727 find_split_point (rtx
*loc
, rtx_insn
*insn
, bool set_src
)
4730 enum rtx_code code
= GET_CODE (x
);
4732 unsigned HOST_WIDE_INT len
= 0;
4733 HOST_WIDE_INT pos
= 0;
4735 rtx inner
= NULL_RTX
;
4737 /* First special-case some codes. */
4741 #ifdef INSN_SCHEDULING
4742 /* If we are making a paradoxical SUBREG invalid, it becomes a split
4744 if (MEM_P (SUBREG_REG (x
)))
4747 return find_split_point (&SUBREG_REG (x
), insn
, false);
4750 /* If we have (mem (const ..)) or (mem (symbol_ref ...)), split it
4751 using LO_SUM and HIGH. */
4752 if (HAVE_lo_sum
&& (GET_CODE (XEXP (x
, 0)) == CONST
4753 || GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
))
4755 machine_mode address_mode
= get_address_mode (x
);
4758 gen_rtx_LO_SUM (address_mode
,
4759 gen_rtx_HIGH (address_mode
, XEXP (x
, 0)),
4761 return &XEXP (XEXP (x
, 0), 0);
4764 /* If we have a PLUS whose second operand is a constant and the
4765 address is not valid, perhaps will can split it up using
4766 the machine-specific way to split large constants. We use
4767 the first pseudo-reg (one of the virtual regs) as a placeholder;
4768 it will not remain in the result. */
4769 if (GET_CODE (XEXP (x
, 0)) == PLUS
4770 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
4771 && ! memory_address_addr_space_p (GET_MODE (x
), XEXP (x
, 0),
4772 MEM_ADDR_SPACE (x
)))
4774 rtx reg
= regno_reg_rtx
[FIRST_PSEUDO_REGISTER
];
4775 rtx_insn
*seq
= combine_split_insns (gen_rtx_SET (reg
, XEXP (x
, 0)),
4778 /* This should have produced two insns, each of which sets our
4779 placeholder. If the source of the second is a valid address,
4780 we can make put both sources together and make a split point
4784 && NEXT_INSN (seq
) != NULL_RTX
4785 && NEXT_INSN (NEXT_INSN (seq
)) == NULL_RTX
4786 && NONJUMP_INSN_P (seq
)
4787 && GET_CODE (PATTERN (seq
)) == SET
4788 && SET_DEST (PATTERN (seq
)) == reg
4789 && ! reg_mentioned_p (reg
,
4790 SET_SRC (PATTERN (seq
)))
4791 && NONJUMP_INSN_P (NEXT_INSN (seq
))
4792 && GET_CODE (PATTERN (NEXT_INSN (seq
))) == SET
4793 && SET_DEST (PATTERN (NEXT_INSN (seq
))) == reg
4794 && memory_address_addr_space_p
4795 (GET_MODE (x
), SET_SRC (PATTERN (NEXT_INSN (seq
))),
4796 MEM_ADDR_SPACE (x
)))
4798 rtx src1
= SET_SRC (PATTERN (seq
));
4799 rtx src2
= SET_SRC (PATTERN (NEXT_INSN (seq
)));
4801 /* Replace the placeholder in SRC2 with SRC1. If we can
4802 find where in SRC2 it was placed, that can become our
4803 split point and we can replace this address with SRC2.
4804 Just try two obvious places. */
4806 src2
= replace_rtx (src2
, reg
, src1
);
4808 if (XEXP (src2
, 0) == src1
)
4809 split
= &XEXP (src2
, 0);
4810 else if (GET_RTX_FORMAT (GET_CODE (XEXP (src2
, 0)))[0] == 'e'
4811 && XEXP (XEXP (src2
, 0), 0) == src1
)
4812 split
= &XEXP (XEXP (src2
, 0), 0);
4816 SUBST (XEXP (x
, 0), src2
);
4821 /* If that didn't work, perhaps the first operand is complex and
4822 needs to be computed separately, so make a split point there.
4823 This will occur on machines that just support REG + CONST
4824 and have a constant moved through some previous computation. */
4826 else if (!OBJECT_P (XEXP (XEXP (x
, 0), 0))
4827 && ! (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SUBREG
4828 && OBJECT_P (SUBREG_REG (XEXP (XEXP (x
, 0), 0)))))
4829 return &XEXP (XEXP (x
, 0), 0);
4832 /* If we have a PLUS whose first operand is complex, try computing it
4833 separately by making a split there. */
4834 if (GET_CODE (XEXP (x
, 0)) == PLUS
4835 && ! memory_address_addr_space_p (GET_MODE (x
), XEXP (x
, 0),
4837 && ! OBJECT_P (XEXP (XEXP (x
, 0), 0))
4838 && ! (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SUBREG
4839 && OBJECT_P (SUBREG_REG (XEXP (XEXP (x
, 0), 0)))))
4840 return &XEXP (XEXP (x
, 0), 0);
4844 /* If SET_DEST is CC0 and SET_SRC is not an operand, a COMPARE, or a
4845 ZERO_EXTRACT, the most likely reason why this doesn't match is that
4846 we need to put the operand into a register. So split at that
4849 if (SET_DEST (x
) == cc0_rtx
4850 && GET_CODE (SET_SRC (x
)) != COMPARE
4851 && GET_CODE (SET_SRC (x
)) != ZERO_EXTRACT
4852 && !OBJECT_P (SET_SRC (x
))
4853 && ! (GET_CODE (SET_SRC (x
)) == SUBREG
4854 && OBJECT_P (SUBREG_REG (SET_SRC (x
)))))
4855 return &SET_SRC (x
);
4857 /* See if we can split SET_SRC as it stands. */
4858 split
= find_split_point (&SET_SRC (x
), insn
, true);
4859 if (split
&& split
!= &SET_SRC (x
))
4862 /* See if we can split SET_DEST as it stands. */
4863 split
= find_split_point (&SET_DEST (x
), insn
, false);
4864 if (split
&& split
!= &SET_DEST (x
))
4867 /* See if this is a bitfield assignment with everything constant. If
4868 so, this is an IOR of an AND, so split it into that. */
4869 if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
4870 && HWI_COMPUTABLE_MODE_P (GET_MODE (XEXP (SET_DEST (x
), 0)))
4871 && CONST_INT_P (XEXP (SET_DEST (x
), 1))
4872 && CONST_INT_P (XEXP (SET_DEST (x
), 2))
4873 && CONST_INT_P (SET_SRC (x
))
4874 && ((INTVAL (XEXP (SET_DEST (x
), 1))
4875 + INTVAL (XEXP (SET_DEST (x
), 2)))
4876 <= GET_MODE_PRECISION (GET_MODE (XEXP (SET_DEST (x
), 0))))
4877 && ! side_effects_p (XEXP (SET_DEST (x
), 0)))
4879 HOST_WIDE_INT pos
= INTVAL (XEXP (SET_DEST (x
), 2));
4880 unsigned HOST_WIDE_INT len
= INTVAL (XEXP (SET_DEST (x
), 1));
4881 unsigned HOST_WIDE_INT src
= INTVAL (SET_SRC (x
));
4882 rtx dest
= XEXP (SET_DEST (x
), 0);
4883 machine_mode mode
= GET_MODE (dest
);
4884 unsigned HOST_WIDE_INT mask
4885 = ((unsigned HOST_WIDE_INT
) 1 << len
) - 1;
4888 if (BITS_BIG_ENDIAN
)
4889 pos
= GET_MODE_PRECISION (mode
) - len
- pos
;
4891 or_mask
= gen_int_mode (src
<< pos
, mode
);
4894 simplify_gen_binary (IOR
, mode
, dest
, or_mask
));
4897 rtx negmask
= gen_int_mode (~(mask
<< pos
), mode
);
4899 simplify_gen_binary (IOR
, mode
,
4900 simplify_gen_binary (AND
, mode
,
4905 SUBST (SET_DEST (x
), dest
);
4907 split
= find_split_point (&SET_SRC (x
), insn
, true);
4908 if (split
&& split
!= &SET_SRC (x
))
4912 /* Otherwise, see if this is an operation that we can split into two.
4913 If so, try to split that. */
4914 code
= GET_CODE (SET_SRC (x
));
4919 /* If we are AND'ing with a large constant that is only a single
4920 bit and the result is only being used in a context where we
4921 need to know if it is zero or nonzero, replace it with a bit
4922 extraction. This will avoid the large constant, which might
4923 have taken more than one insn to make. If the constant were
4924 not a valid argument to the AND but took only one insn to make,
4925 this is no worse, but if it took more than one insn, it will
4928 if (CONST_INT_P (XEXP (SET_SRC (x
), 1))
4929 && REG_P (XEXP (SET_SRC (x
), 0))
4930 && (pos
= exact_log2 (UINTVAL (XEXP (SET_SRC (x
), 1)))) >= 7
4931 && REG_P (SET_DEST (x
))
4932 && (split
= find_single_use (SET_DEST (x
), insn
, NULL
)) != 0
4933 && (GET_CODE (*split
) == EQ
|| GET_CODE (*split
) == NE
)
4934 && XEXP (*split
, 0) == SET_DEST (x
)
4935 && XEXP (*split
, 1) == const0_rtx
)
4937 rtx extraction
= make_extraction (GET_MODE (SET_DEST (x
)),
4938 XEXP (SET_SRC (x
), 0),
4939 pos
, NULL_RTX
, 1, 1, 0, 0);
4940 if (extraction
!= 0)
4942 SUBST (SET_SRC (x
), extraction
);
4943 return find_split_point (loc
, insn
, false);
4949 /* If STORE_FLAG_VALUE is -1, this is (NE X 0) and only one bit of X
4950 is known to be on, this can be converted into a NEG of a shift. */
4951 if (STORE_FLAG_VALUE
== -1 && XEXP (SET_SRC (x
), 1) == const0_rtx
4952 && GET_MODE (SET_SRC (x
)) == GET_MODE (XEXP (SET_SRC (x
), 0))
4953 && 1 <= (pos
= exact_log2
4954 (nonzero_bits (XEXP (SET_SRC (x
), 0),
4955 GET_MODE (XEXP (SET_SRC (x
), 0))))))
4957 machine_mode mode
= GET_MODE (XEXP (SET_SRC (x
), 0));
4961 gen_rtx_LSHIFTRT (mode
,
4962 XEXP (SET_SRC (x
), 0),
4965 split
= find_split_point (&SET_SRC (x
), insn
, true);
4966 if (split
&& split
!= &SET_SRC (x
))
4972 inner
= XEXP (SET_SRC (x
), 0);
4974 /* We can't optimize if either mode is a partial integer
4975 mode as we don't know how many bits are significant
4977 if (GET_MODE_CLASS (GET_MODE (inner
)) == MODE_PARTIAL_INT
4978 || GET_MODE_CLASS (GET_MODE (SET_SRC (x
))) == MODE_PARTIAL_INT
)
4982 len
= GET_MODE_PRECISION (GET_MODE (inner
));
4988 if (CONST_INT_P (XEXP (SET_SRC (x
), 1))
4989 && CONST_INT_P (XEXP (SET_SRC (x
), 2)))
4991 inner
= XEXP (SET_SRC (x
), 0);
4992 len
= INTVAL (XEXP (SET_SRC (x
), 1));
4993 pos
= INTVAL (XEXP (SET_SRC (x
), 2));
4995 if (BITS_BIG_ENDIAN
)
4996 pos
= GET_MODE_PRECISION (GET_MODE (inner
)) - len
- pos
;
4997 unsignedp
= (code
== ZERO_EXTRACT
);
5006 && pos
+ len
<= GET_MODE_PRECISION (GET_MODE (inner
)))
5008 machine_mode mode
= GET_MODE (SET_SRC (x
));
5010 /* For unsigned, we have a choice of a shift followed by an
5011 AND or two shifts. Use two shifts for field sizes where the
5012 constant might be too large. We assume here that we can
5013 always at least get 8-bit constants in an AND insn, which is
5014 true for every current RISC. */
5016 if (unsignedp
&& len
<= 8)
5018 unsigned HOST_WIDE_INT mask
5019 = ((unsigned HOST_WIDE_INT
) 1 << len
) - 1;
5023 (mode
, gen_lowpart (mode
, inner
),
5025 gen_int_mode (mask
, mode
)));
5027 split
= find_split_point (&SET_SRC (x
), insn
, true);
5028 if (split
&& split
!= &SET_SRC (x
))
5035 (unsignedp
? LSHIFTRT
: ASHIFTRT
, mode
,
5036 gen_rtx_ASHIFT (mode
,
5037 gen_lowpart (mode
, inner
),
5038 GEN_INT (GET_MODE_PRECISION (mode
)
5040 GEN_INT (GET_MODE_PRECISION (mode
) - len
)));
5042 split
= find_split_point (&SET_SRC (x
), insn
, true);
5043 if (split
&& split
!= &SET_SRC (x
))
5048 /* See if this is a simple operation with a constant as the second
5049 operand. It might be that this constant is out of range and hence
5050 could be used as a split point. */
5051 if (BINARY_P (SET_SRC (x
))
5052 && CONSTANT_P (XEXP (SET_SRC (x
), 1))
5053 && (OBJECT_P (XEXP (SET_SRC (x
), 0))
5054 || (GET_CODE (XEXP (SET_SRC (x
), 0)) == SUBREG
5055 && OBJECT_P (SUBREG_REG (XEXP (SET_SRC (x
), 0))))))
5056 return &XEXP (SET_SRC (x
), 1);
5058 /* Finally, see if this is a simple operation with its first operand
5059 not in a register. The operation might require this operand in a
5060 register, so return it as a split point. We can always do this
5061 because if the first operand were another operation, we would have
5062 already found it as a split point. */
5063 if ((BINARY_P (SET_SRC (x
)) || UNARY_P (SET_SRC (x
)))
5064 && ! register_operand (XEXP (SET_SRC (x
), 0), VOIDmode
))
5065 return &XEXP (SET_SRC (x
), 0);
5071 /* We write NOR as (and (not A) (not B)), but if we don't have a NOR,
5072 it is better to write this as (not (ior A B)) so we can split it.
5073 Similarly for IOR. */
5074 if (GET_CODE (XEXP (x
, 0)) == NOT
&& GET_CODE (XEXP (x
, 1)) == NOT
)
5077 gen_rtx_NOT (GET_MODE (x
),
5078 gen_rtx_fmt_ee (code
== IOR
? AND
: IOR
,
5080 XEXP (XEXP (x
, 0), 0),
5081 XEXP (XEXP (x
, 1), 0))));
5082 return find_split_point (loc
, insn
, set_src
);
5085 /* Many RISC machines have a large set of logical insns. If the
5086 second operand is a NOT, put it first so we will try to split the
5087 other operand first. */
5088 if (GET_CODE (XEXP (x
, 1)) == NOT
)
5090 rtx tem
= XEXP (x
, 0);
5091 SUBST (XEXP (x
, 0), XEXP (x
, 1));
5092 SUBST (XEXP (x
, 1), tem
);
5098 /* Canonicalization can produce (minus A (mult B C)), where C is a
5099 constant. It may be better to try splitting (plus (mult B -C) A)
5100 instead if this isn't a multiply by a power of two. */
5101 if (set_src
&& code
== MINUS
&& GET_CODE (XEXP (x
, 1)) == MULT
5102 && GET_CODE (XEXP (XEXP (x
, 1), 1)) == CONST_INT
5103 && exact_log2 (INTVAL (XEXP (XEXP (x
, 1), 1))) < 0)
5105 machine_mode mode
= GET_MODE (x
);
5106 unsigned HOST_WIDE_INT this_int
= INTVAL (XEXP (XEXP (x
, 1), 1));
5107 HOST_WIDE_INT other_int
= trunc_int_for_mode (-this_int
, mode
);
5108 SUBST (*loc
, gen_rtx_PLUS (mode
,
5110 XEXP (XEXP (x
, 1), 0),
5111 gen_int_mode (other_int
,
5114 return find_split_point (loc
, insn
, set_src
);
5117 /* Split at a multiply-accumulate instruction. However if this is
5118 the SET_SRC, we likely do not have such an instruction and it's
5119 worthless to try this split. */
5121 && (GET_CODE (XEXP (x
, 0)) == MULT
5122 || (GET_CODE (XEXP (x
, 0)) == ASHIFT
5123 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
)))
5130 /* Otherwise, select our actions depending on our rtx class. */
5131 switch (GET_RTX_CLASS (code
))
5133 case RTX_BITFIELD_OPS
: /* This is ZERO_EXTRACT and SIGN_EXTRACT. */
5135 split
= find_split_point (&XEXP (x
, 2), insn
, false);
5138 /* ... fall through ... */
5140 case RTX_COMM_ARITH
:
5142 case RTX_COMM_COMPARE
:
5143 split
= find_split_point (&XEXP (x
, 1), insn
, false);
5146 /* ... fall through ... */
5148 /* Some machines have (and (shift ...) ...) insns. If X is not
5149 an AND, but XEXP (X, 0) is, use it as our split point. */
5150 if (GET_CODE (x
) != AND
&& GET_CODE (XEXP (x
, 0)) == AND
)
5151 return &XEXP (x
, 0);
5153 split
= find_split_point (&XEXP (x
, 0), insn
, false);
5159 /* Otherwise, we don't have a split point. */
5164 /* Throughout X, replace FROM with TO, and return the result.
5165 The result is TO if X is FROM;
5166 otherwise the result is X, but its contents may have been modified.
5167 If they were modified, a record was made in undobuf so that
5168 undo_all will (among other things) return X to its original state.
5170 If the number of changes necessary is too much to record to undo,
5171 the excess changes are not made, so the result is invalid.
5172 The changes already made can still be undone.
5173 undobuf.num_undo is incremented for such changes, so by testing that
5174 the caller can tell whether the result is valid.
5176 `n_occurrences' is incremented each time FROM is replaced.
5178 IN_DEST is nonzero if we are processing the SET_DEST of a SET.
5180 IN_COND is nonzero if we are at the top level of a condition.
5182 UNIQUE_COPY is nonzero if each substitution must be unique. We do this
5183 by copying if `n_occurrences' is nonzero. */
5186 subst (rtx x
, rtx from
, rtx to
, int in_dest
, int in_cond
, int unique_copy
)
5188 enum rtx_code code
= GET_CODE (x
);
5189 machine_mode op0_mode
= VOIDmode
;
5194 /* Two expressions are equal if they are identical copies of a shared
5195 RTX or if they are both registers with the same register number
5198 #define COMBINE_RTX_EQUAL_P(X,Y) \
5200 || (REG_P (X) && REG_P (Y) \
5201 && REGNO (X) == REGNO (Y) && GET_MODE (X) == GET_MODE (Y)))
5203 /* Do not substitute into clobbers of regs -- this will never result in
5205 if (GET_CODE (x
) == CLOBBER
&& REG_P (XEXP (x
, 0)))
5208 if (! in_dest
&& COMBINE_RTX_EQUAL_P (x
, from
))
5211 return (unique_copy
&& n_occurrences
> 1 ? copy_rtx (to
) : to
);
5214 /* If X and FROM are the same register but different modes, they
5215 will not have been seen as equal above. However, the log links code
5216 will make a LOG_LINKS entry for that case. If we do nothing, we
5217 will try to rerecognize our original insn and, when it succeeds,
5218 we will delete the feeding insn, which is incorrect.
5220 So force this insn not to match in this (rare) case. */
5221 if (! in_dest
&& code
== REG
&& REG_P (from
)
5222 && reg_overlap_mentioned_p (x
, from
))
5223 return gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
5225 /* If this is an object, we are done unless it is a MEM or LO_SUM, both
5226 of which may contain things that can be combined. */
5227 if (code
!= MEM
&& code
!= LO_SUM
&& OBJECT_P (x
))
5230 /* It is possible to have a subexpression appear twice in the insn.
5231 Suppose that FROM is a register that appears within TO.
5232 Then, after that subexpression has been scanned once by `subst',
5233 the second time it is scanned, TO may be found. If we were
5234 to scan TO here, we would find FROM within it and create a
5235 self-referent rtl structure which is completely wrong. */
5236 if (COMBINE_RTX_EQUAL_P (x
, to
))
5239 /* Parallel asm_operands need special attention because all of the
5240 inputs are shared across the arms. Furthermore, unsharing the
5241 rtl results in recognition failures. Failure to handle this case
5242 specially can result in circular rtl.
5244 Solve this by doing a normal pass across the first entry of the
5245 parallel, and only processing the SET_DESTs of the subsequent
5248 if (code
== PARALLEL
5249 && GET_CODE (XVECEXP (x
, 0, 0)) == SET
5250 && GET_CODE (SET_SRC (XVECEXP (x
, 0, 0))) == ASM_OPERANDS
)
5252 new_rtx
= subst (XVECEXP (x
, 0, 0), from
, to
, 0, 0, unique_copy
);
5254 /* If this substitution failed, this whole thing fails. */
5255 if (GET_CODE (new_rtx
) == CLOBBER
5256 && XEXP (new_rtx
, 0) == const0_rtx
)
5259 SUBST (XVECEXP (x
, 0, 0), new_rtx
);
5261 for (i
= XVECLEN (x
, 0) - 1; i
>= 1; i
--)
5263 rtx dest
= SET_DEST (XVECEXP (x
, 0, i
));
5266 && GET_CODE (dest
) != CC0
5267 && GET_CODE (dest
) != PC
)
5269 new_rtx
= subst (dest
, from
, to
, 0, 0, unique_copy
);
5271 /* If this substitution failed, this whole thing fails. */
5272 if (GET_CODE (new_rtx
) == CLOBBER
5273 && XEXP (new_rtx
, 0) == const0_rtx
)
5276 SUBST (SET_DEST (XVECEXP (x
, 0, i
)), new_rtx
);
5282 len
= GET_RTX_LENGTH (code
);
5283 fmt
= GET_RTX_FORMAT (code
);
5285 /* We don't need to process a SET_DEST that is a register, CC0,
5286 or PC, so set up to skip this common case. All other cases
5287 where we want to suppress replacing something inside a
5288 SET_SRC are handled via the IN_DEST operand. */
5290 && (REG_P (SET_DEST (x
))
5291 || GET_CODE (SET_DEST (x
)) == CC0
5292 || GET_CODE (SET_DEST (x
)) == PC
))
5295 /* Trying to simplify the operands of a widening MULT is not likely
5296 to create RTL matching a machine insn. */
5298 && (GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
5299 || GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
)
5300 && (GET_CODE (XEXP (x
, 1)) == ZERO_EXTEND
5301 || GET_CODE (XEXP (x
, 1)) == SIGN_EXTEND
)
5302 && REG_P (XEXP (XEXP (x
, 0), 0))
5303 && REG_P (XEXP (XEXP (x
, 1), 0))
5308 /* Get the mode of operand 0 in case X is now a SIGN_EXTEND of a
5311 op0_mode
= GET_MODE (XEXP (x
, 0));
5313 for (i
= 0; i
< len
; i
++)
5318 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
5320 if (COMBINE_RTX_EQUAL_P (XVECEXP (x
, i
, j
), from
))
5322 new_rtx
= (unique_copy
&& n_occurrences
5323 ? copy_rtx (to
) : to
);
5328 new_rtx
= subst (XVECEXP (x
, i
, j
), from
, to
, 0, 0,
5331 /* If this substitution failed, this whole thing
5333 if (GET_CODE (new_rtx
) == CLOBBER
5334 && XEXP (new_rtx
, 0) == const0_rtx
)
5338 SUBST (XVECEXP (x
, i
, j
), new_rtx
);
5341 else if (fmt
[i
] == 'e')
5343 /* If this is a register being set, ignore it. */
5344 new_rtx
= XEXP (x
, i
);
5347 && (((code
== SUBREG
|| code
== ZERO_EXTRACT
)
5349 || code
== STRICT_LOW_PART
))
5352 else if (COMBINE_RTX_EQUAL_P (XEXP (x
, i
), from
))
5354 /* In general, don't install a subreg involving two
5355 modes not tieable. It can worsen register
5356 allocation, and can even make invalid reload
5357 insns, since the reg inside may need to be copied
5358 from in the outside mode, and that may be invalid
5359 if it is an fp reg copied in integer mode.
5361 We allow two exceptions to this: It is valid if
5362 it is inside another SUBREG and the mode of that
5363 SUBREG and the mode of the inside of TO is
5364 tieable and it is valid if X is a SET that copies
5367 if (GET_CODE (to
) == SUBREG
5368 && ! MODES_TIEABLE_P (GET_MODE (to
),
5369 GET_MODE (SUBREG_REG (to
)))
5370 && ! (code
== SUBREG
5371 && MODES_TIEABLE_P (GET_MODE (x
),
5372 GET_MODE (SUBREG_REG (to
))))
5376 && XEXP (x
, 0) == cc0_rtx
))))
5377 return gen_rtx_CLOBBER (VOIDmode
, const0_rtx
);
5381 && REGNO (to
) < FIRST_PSEUDO_REGISTER
5382 && simplify_subreg_regno (REGNO (to
), GET_MODE (to
),
5385 return gen_rtx_CLOBBER (VOIDmode
, const0_rtx
);
5387 new_rtx
= (unique_copy
&& n_occurrences
? copy_rtx (to
) : to
);
5391 /* If we are in a SET_DEST, suppress most cases unless we
5392 have gone inside a MEM, in which case we want to
5393 simplify the address. We assume here that things that
5394 are actually part of the destination have their inner
5395 parts in the first expression. This is true for SUBREG,
5396 STRICT_LOW_PART, and ZERO_EXTRACT, which are the only
5397 things aside from REG and MEM that should appear in a
5399 new_rtx
= subst (XEXP (x
, i
), from
, to
,
5401 && (code
== SUBREG
|| code
== STRICT_LOW_PART
5402 || code
== ZERO_EXTRACT
))
5405 code
== IF_THEN_ELSE
&& i
== 0,
5408 /* If we found that we will have to reject this combination,
5409 indicate that by returning the CLOBBER ourselves, rather than
5410 an expression containing it. This will speed things up as
5411 well as prevent accidents where two CLOBBERs are considered
5412 to be equal, thus producing an incorrect simplification. */
5414 if (GET_CODE (new_rtx
) == CLOBBER
&& XEXP (new_rtx
, 0) == const0_rtx
)
5417 if (GET_CODE (x
) == SUBREG
&& CONST_SCALAR_INT_P (new_rtx
))
5419 machine_mode mode
= GET_MODE (x
);
5421 x
= simplify_subreg (GET_MODE (x
), new_rtx
,
5422 GET_MODE (SUBREG_REG (x
)),
5425 x
= gen_rtx_CLOBBER (mode
, const0_rtx
);
5427 else if (CONST_SCALAR_INT_P (new_rtx
)
5428 && GET_CODE (x
) == ZERO_EXTEND
)
5430 x
= simplify_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
5431 new_rtx
, GET_MODE (XEXP (x
, 0)));
5435 SUBST (XEXP (x
, i
), new_rtx
);
5440 /* Check if we are loading something from the constant pool via float
5441 extension; in this case we would undo compress_float_constant
5442 optimization and degenerate constant load to an immediate value. */
5443 if (GET_CODE (x
) == FLOAT_EXTEND
5444 && MEM_P (XEXP (x
, 0))
5445 && MEM_READONLY_P (XEXP (x
, 0)))
5447 rtx tmp
= avoid_constant_pool_reference (x
);
5452 /* Try to simplify X. If the simplification changed the code, it is likely
5453 that further simplification will help, so loop, but limit the number
5454 of repetitions that will be performed. */
5456 for (i
= 0; i
< 4; i
++)
5458 /* If X is sufficiently simple, don't bother trying to do anything
5460 if (code
!= CONST_INT
&& code
!= REG
&& code
!= CLOBBER
)
5461 x
= combine_simplify_rtx (x
, op0_mode
, in_dest
, in_cond
);
5463 if (GET_CODE (x
) == code
)
5466 code
= GET_CODE (x
);
5468 /* We no longer know the original mode of operand 0 since we
5469 have changed the form of X) */
5470 op0_mode
= VOIDmode
;
5476 /* Simplify X, a piece of RTL. We just operate on the expression at the
5477 outer level; call `subst' to simplify recursively. Return the new
5480 OP0_MODE is the original mode of XEXP (x, 0). IN_DEST is nonzero
5481 if we are inside a SET_DEST. IN_COND is nonzero if we are at the top level
5485 combine_simplify_rtx (rtx x
, machine_mode op0_mode
, int in_dest
,
5488 enum rtx_code code
= GET_CODE (x
);
5489 machine_mode mode
= GET_MODE (x
);
5493 /* If this is a commutative operation, put a constant last and a complex
5494 expression first. We don't need to do this for comparisons here. */
5495 if (COMMUTATIVE_ARITH_P (x
)
5496 && swap_commutative_operands_p (XEXP (x
, 0), XEXP (x
, 1)))
5499 SUBST (XEXP (x
, 0), XEXP (x
, 1));
5500 SUBST (XEXP (x
, 1), temp
);
5503 /* Try to fold this expression in case we have constants that weren't
5506 switch (GET_RTX_CLASS (code
))
5509 if (op0_mode
== VOIDmode
)
5510 op0_mode
= GET_MODE (XEXP (x
, 0));
5511 temp
= simplify_unary_operation (code
, mode
, XEXP (x
, 0), op0_mode
);
5514 case RTX_COMM_COMPARE
:
5516 machine_mode cmp_mode
= GET_MODE (XEXP (x
, 0));
5517 if (cmp_mode
== VOIDmode
)
5519 cmp_mode
= GET_MODE (XEXP (x
, 1));
5520 if (cmp_mode
== VOIDmode
)
5521 cmp_mode
= op0_mode
;
5523 temp
= simplify_relational_operation (code
, mode
, cmp_mode
,
5524 XEXP (x
, 0), XEXP (x
, 1));
5527 case RTX_COMM_ARITH
:
5529 temp
= simplify_binary_operation (code
, mode
, XEXP (x
, 0), XEXP (x
, 1));
5531 case RTX_BITFIELD_OPS
:
5533 temp
= simplify_ternary_operation (code
, mode
, op0_mode
, XEXP (x
, 0),
5534 XEXP (x
, 1), XEXP (x
, 2));
5543 code
= GET_CODE (temp
);
5544 op0_mode
= VOIDmode
;
5545 mode
= GET_MODE (temp
);
5548 /* If this is a simple operation applied to an IF_THEN_ELSE, try
5549 applying it to the arms of the IF_THEN_ELSE. This often simplifies
5550 things. Check for cases where both arms are testing the same
5553 Don't do anything if all operands are very simple. */
5556 && ((!OBJECT_P (XEXP (x
, 0))
5557 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5558 && OBJECT_P (SUBREG_REG (XEXP (x
, 0)))))
5559 || (!OBJECT_P (XEXP (x
, 1))
5560 && ! (GET_CODE (XEXP (x
, 1)) == SUBREG
5561 && OBJECT_P (SUBREG_REG (XEXP (x
, 1)))))))
5563 && (!OBJECT_P (XEXP (x
, 0))
5564 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5565 && OBJECT_P (SUBREG_REG (XEXP (x
, 0)))))))
5567 rtx cond
, true_rtx
, false_rtx
;
5569 cond
= if_then_else_cond (x
, &true_rtx
, &false_rtx
);
5571 /* If everything is a comparison, what we have is highly unlikely
5572 to be simpler, so don't use it. */
5573 && ! (COMPARISON_P (x
)
5574 && (COMPARISON_P (true_rtx
) || COMPARISON_P (false_rtx
))))
5576 rtx cop1
= const0_rtx
;
5577 enum rtx_code cond_code
= simplify_comparison (NE
, &cond
, &cop1
);
5579 if (cond_code
== NE
&& COMPARISON_P (cond
))
5582 /* Simplify the alternative arms; this may collapse the true and
5583 false arms to store-flag values. Be careful to use copy_rtx
5584 here since true_rtx or false_rtx might share RTL with x as a
5585 result of the if_then_else_cond call above. */
5586 true_rtx
= subst (copy_rtx (true_rtx
), pc_rtx
, pc_rtx
, 0, 0, 0);
5587 false_rtx
= subst (copy_rtx (false_rtx
), pc_rtx
, pc_rtx
, 0, 0, 0);
5589 /* If true_rtx and false_rtx are not general_operands, an if_then_else
5590 is unlikely to be simpler. */
5591 if (general_operand (true_rtx
, VOIDmode
)
5592 && general_operand (false_rtx
, VOIDmode
))
5594 enum rtx_code reversed
;
5596 /* Restarting if we generate a store-flag expression will cause
5597 us to loop. Just drop through in this case. */
5599 /* If the result values are STORE_FLAG_VALUE and zero, we can
5600 just make the comparison operation. */
5601 if (true_rtx
== const_true_rtx
&& false_rtx
== const0_rtx
)
5602 x
= simplify_gen_relational (cond_code
, mode
, VOIDmode
,
5604 else if (true_rtx
== const0_rtx
&& false_rtx
== const_true_rtx
5605 && ((reversed
= reversed_comparison_code_parts
5606 (cond_code
, cond
, cop1
, NULL
))
5608 x
= simplify_gen_relational (reversed
, mode
, VOIDmode
,
5611 /* Likewise, we can make the negate of a comparison operation
5612 if the result values are - STORE_FLAG_VALUE and zero. */
5613 else if (CONST_INT_P (true_rtx
)
5614 && INTVAL (true_rtx
) == - STORE_FLAG_VALUE
5615 && false_rtx
== const0_rtx
)
5616 x
= simplify_gen_unary (NEG
, mode
,
5617 simplify_gen_relational (cond_code
,
5621 else if (CONST_INT_P (false_rtx
)
5622 && INTVAL (false_rtx
) == - STORE_FLAG_VALUE
5623 && true_rtx
== const0_rtx
5624 && ((reversed
= reversed_comparison_code_parts
5625 (cond_code
, cond
, cop1
, NULL
))
5627 x
= simplify_gen_unary (NEG
, mode
,
5628 simplify_gen_relational (reversed
,
5633 return gen_rtx_IF_THEN_ELSE (mode
,
5634 simplify_gen_relational (cond_code
,
5639 true_rtx
, false_rtx
);
5641 code
= GET_CODE (x
);
5642 op0_mode
= VOIDmode
;
5647 /* First see if we can apply the inverse distributive law. */
5648 if (code
== PLUS
|| code
== MINUS
5649 || code
== AND
|| code
== IOR
|| code
== XOR
)
5651 x
= apply_distributive_law (x
);
5652 code
= GET_CODE (x
);
5653 op0_mode
= VOIDmode
;
5656 /* If CODE is an associative operation not otherwise handled, see if we
5657 can associate some operands. This can win if they are constants or
5658 if they are logically related (i.e. (a & b) & a). */
5659 if ((code
== PLUS
|| code
== MINUS
|| code
== MULT
|| code
== DIV
5660 || code
== AND
|| code
== IOR
|| code
== XOR
5661 || code
== SMAX
|| code
== SMIN
|| code
== UMAX
|| code
== UMIN
)
5662 && ((INTEGRAL_MODE_P (mode
) && code
!= DIV
)
5663 || (flag_associative_math
&& FLOAT_MODE_P (mode
))))
5665 if (GET_CODE (XEXP (x
, 0)) == code
)
5667 rtx other
= XEXP (XEXP (x
, 0), 0);
5668 rtx inner_op0
= XEXP (XEXP (x
, 0), 1);
5669 rtx inner_op1
= XEXP (x
, 1);
5672 /* Make sure we pass the constant operand if any as the second
5673 one if this is a commutative operation. */
5674 if (CONSTANT_P (inner_op0
) && COMMUTATIVE_ARITH_P (x
))
5675 std::swap (inner_op0
, inner_op1
);
5676 inner
= simplify_binary_operation (code
== MINUS
? PLUS
5677 : code
== DIV
? MULT
5679 mode
, inner_op0
, inner_op1
);
5681 /* For commutative operations, try the other pair if that one
5683 if (inner
== 0 && COMMUTATIVE_ARITH_P (x
))
5685 other
= XEXP (XEXP (x
, 0), 1);
5686 inner
= simplify_binary_operation (code
, mode
,
5687 XEXP (XEXP (x
, 0), 0),
5692 return simplify_gen_binary (code
, mode
, other
, inner
);
5696 /* A little bit of algebraic simplification here. */
5700 /* Ensure that our address has any ASHIFTs converted to MULT in case
5701 address-recognizing predicates are called later. */
5702 temp
= make_compound_operation (XEXP (x
, 0), MEM
);
5703 SUBST (XEXP (x
, 0), temp
);
5707 if (op0_mode
== VOIDmode
)
5708 op0_mode
= GET_MODE (SUBREG_REG (x
));
5710 /* See if this can be moved to simplify_subreg. */
5711 if (CONSTANT_P (SUBREG_REG (x
))
5712 && subreg_lowpart_offset (mode
, op0_mode
) == SUBREG_BYTE (x
)
5713 /* Don't call gen_lowpart if the inner mode
5714 is VOIDmode and we cannot simplify it, as SUBREG without
5715 inner mode is invalid. */
5716 && (GET_MODE (SUBREG_REG (x
)) != VOIDmode
5717 || gen_lowpart_common (mode
, SUBREG_REG (x
))))
5718 return gen_lowpart (mode
, SUBREG_REG (x
));
5720 if (GET_MODE_CLASS (GET_MODE (SUBREG_REG (x
))) == MODE_CC
)
5724 temp
= simplify_subreg (mode
, SUBREG_REG (x
), op0_mode
,
5729 /* If op is known to have all lower bits zero, the result is zero. */
5731 && SCALAR_INT_MODE_P (mode
)
5732 && SCALAR_INT_MODE_P (op0_mode
)
5733 && GET_MODE_PRECISION (mode
) < GET_MODE_PRECISION (op0_mode
)
5734 && subreg_lowpart_offset (mode
, op0_mode
) == SUBREG_BYTE (x
)
5735 && HWI_COMPUTABLE_MODE_P (op0_mode
)
5736 && (nonzero_bits (SUBREG_REG (x
), op0_mode
)
5737 & GET_MODE_MASK (mode
)) == 0)
5738 return CONST0_RTX (mode
);
5741 /* Don't change the mode of the MEM if that would change the meaning
5743 if (MEM_P (SUBREG_REG (x
))
5744 && (MEM_VOLATILE_P (SUBREG_REG (x
))
5745 || mode_dependent_address_p (XEXP (SUBREG_REG (x
), 0),
5746 MEM_ADDR_SPACE (SUBREG_REG (x
)))))
5747 return gen_rtx_CLOBBER (mode
, const0_rtx
);
5749 /* Note that we cannot do any narrowing for non-constants since
5750 we might have been counting on using the fact that some bits were
5751 zero. We now do this in the SET. */
5756 temp
= expand_compound_operation (XEXP (x
, 0));
5758 /* For C equal to the width of MODE minus 1, (neg (ashiftrt X C)) can be
5759 replaced by (lshiftrt X C). This will convert
5760 (neg (sign_extract X 1 Y)) to (zero_extract X 1 Y). */
5762 if (GET_CODE (temp
) == ASHIFTRT
5763 && CONST_INT_P (XEXP (temp
, 1))
5764 && INTVAL (XEXP (temp
, 1)) == GET_MODE_PRECISION (mode
) - 1)
5765 return simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
, XEXP (temp
, 0),
5766 INTVAL (XEXP (temp
, 1)));
5768 /* If X has only a single bit that might be nonzero, say, bit I, convert
5769 (neg X) to (ashiftrt (ashift X C-I) C-I) where C is the bitsize of
5770 MODE minus 1. This will convert (neg (zero_extract X 1 Y)) to
5771 (sign_extract X 1 Y). But only do this if TEMP isn't a register
5772 or a SUBREG of one since we'd be making the expression more
5773 complex if it was just a register. */
5776 && ! (GET_CODE (temp
) == SUBREG
5777 && REG_P (SUBREG_REG (temp
)))
5778 && (i
= exact_log2 (nonzero_bits (temp
, mode
))) >= 0)
5780 rtx temp1
= simplify_shift_const
5781 (NULL_RTX
, ASHIFTRT
, mode
,
5782 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, temp
,
5783 GET_MODE_PRECISION (mode
) - 1 - i
),
5784 GET_MODE_PRECISION (mode
) - 1 - i
);
5786 /* If all we did was surround TEMP with the two shifts, we
5787 haven't improved anything, so don't use it. Otherwise,
5788 we are better off with TEMP1. */
5789 if (GET_CODE (temp1
) != ASHIFTRT
5790 || GET_CODE (XEXP (temp1
, 0)) != ASHIFT
5791 || XEXP (XEXP (temp1
, 0), 0) != temp
)
5797 /* We can't handle truncation to a partial integer mode here
5798 because we don't know the real bitsize of the partial
5800 if (GET_MODE_CLASS (mode
) == MODE_PARTIAL_INT
)
5803 if (HWI_COMPUTABLE_MODE_P (mode
))
5805 force_to_mode (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)),
5806 GET_MODE_MASK (mode
), 0));
5808 /* We can truncate a constant value and return it. */
5809 if (CONST_INT_P (XEXP (x
, 0)))
5810 return gen_int_mode (INTVAL (XEXP (x
, 0)), mode
);
5812 /* Similarly to what we do in simplify-rtx.c, a truncate of a register
5813 whose value is a comparison can be replaced with a subreg if
5814 STORE_FLAG_VALUE permits. */
5815 if (HWI_COMPUTABLE_MODE_P (mode
)
5816 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (mode
)) == 0
5817 && (temp
= get_last_value (XEXP (x
, 0)))
5818 && COMPARISON_P (temp
))
5819 return gen_lowpart (mode
, XEXP (x
, 0));
5823 /* (const (const X)) can become (const X). Do it this way rather than
5824 returning the inner CONST since CONST can be shared with a
5826 if (GET_CODE (XEXP (x
, 0)) == CONST
)
5827 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
5831 /* Convert (lo_sum (high FOO) FOO) to FOO. This is necessary so we
5832 can add in an offset. find_split_point will split this address up
5833 again if it doesn't match. */
5834 if (HAVE_lo_sum
&& GET_CODE (XEXP (x
, 0)) == HIGH
5835 && rtx_equal_p (XEXP (XEXP (x
, 0), 0), XEXP (x
, 1)))
5840 /* (plus (xor (and <foo> (const_int pow2 - 1)) <c>) <-c>)
5841 when c is (const_int (pow2 + 1) / 2) is a sign extension of a
5842 bit-field and can be replaced by either a sign_extend or a
5843 sign_extract. The `and' may be a zero_extend and the two
5844 <c>, -<c> constants may be reversed. */
5845 if (GET_CODE (XEXP (x
, 0)) == XOR
5846 && CONST_INT_P (XEXP (x
, 1))
5847 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
5848 && INTVAL (XEXP (x
, 1)) == -INTVAL (XEXP (XEXP (x
, 0), 1))
5849 && ((i
= exact_log2 (UINTVAL (XEXP (XEXP (x
, 0), 1)))) >= 0
5850 || (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0)
5851 && HWI_COMPUTABLE_MODE_P (mode
)
5852 && ((GET_CODE (XEXP (XEXP (x
, 0), 0)) == AND
5853 && CONST_INT_P (XEXP (XEXP (XEXP (x
, 0), 0), 1))
5854 && (UINTVAL (XEXP (XEXP (XEXP (x
, 0), 0), 1))
5855 == ((unsigned HOST_WIDE_INT
) 1 << (i
+ 1)) - 1))
5856 || (GET_CODE (XEXP (XEXP (x
, 0), 0)) == ZERO_EXTEND
5857 && (GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)))
5858 == (unsigned int) i
+ 1))))
5859 return simplify_shift_const
5860 (NULL_RTX
, ASHIFTRT
, mode
,
5861 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
5862 XEXP (XEXP (XEXP (x
, 0), 0), 0),
5863 GET_MODE_PRECISION (mode
) - (i
+ 1)),
5864 GET_MODE_PRECISION (mode
) - (i
+ 1));
5866 /* If only the low-order bit of X is possibly nonzero, (plus x -1)
5867 can become (ashiftrt (ashift (xor x 1) C) C) where C is
5868 the bitsize of the mode - 1. This allows simplification of
5869 "a = (b & 8) == 0;" */
5870 if (XEXP (x
, 1) == constm1_rtx
5871 && !REG_P (XEXP (x
, 0))
5872 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
5873 && REG_P (SUBREG_REG (XEXP (x
, 0))))
5874 && nonzero_bits (XEXP (x
, 0), mode
) == 1)
5875 return simplify_shift_const (NULL_RTX
, ASHIFTRT
, mode
,
5876 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
5877 gen_rtx_XOR (mode
, XEXP (x
, 0), const1_rtx
),
5878 GET_MODE_PRECISION (mode
) - 1),
5879 GET_MODE_PRECISION (mode
) - 1);
5881 /* If we are adding two things that have no bits in common, convert
5882 the addition into an IOR. This will often be further simplified,
5883 for example in cases like ((a & 1) + (a & 2)), which can
5886 if (HWI_COMPUTABLE_MODE_P (mode
)
5887 && (nonzero_bits (XEXP (x
, 0), mode
)
5888 & nonzero_bits (XEXP (x
, 1), mode
)) == 0)
5890 /* Try to simplify the expression further. */
5891 rtx tor
= simplify_gen_binary (IOR
, mode
, XEXP (x
, 0), XEXP (x
, 1));
5892 temp
= combine_simplify_rtx (tor
, VOIDmode
, in_dest
, 0);
5894 /* If we could, great. If not, do not go ahead with the IOR
5895 replacement, since PLUS appears in many special purpose
5896 address arithmetic instructions. */
5897 if (GET_CODE (temp
) != CLOBBER
5898 && (GET_CODE (temp
) != IOR
5899 || ((XEXP (temp
, 0) != XEXP (x
, 0)
5900 || XEXP (temp
, 1) != XEXP (x
, 1))
5901 && (XEXP (temp
, 0) != XEXP (x
, 1)
5902 || XEXP (temp
, 1) != XEXP (x
, 0)))))
5906 /* Canonicalize x + x into x << 1. */
5907 if (GET_MODE_CLASS (mode
) == MODE_INT
5908 && rtx_equal_p (XEXP (x
, 0), XEXP (x
, 1))
5909 && !side_effects_p (XEXP (x
, 0)))
5910 return simplify_gen_binary (ASHIFT
, mode
, XEXP (x
, 0), const1_rtx
);
5915 /* (minus <foo> (and <foo> (const_int -pow2))) becomes
5916 (and <foo> (const_int pow2-1)) */
5917 if (GET_CODE (XEXP (x
, 1)) == AND
5918 && CONST_INT_P (XEXP (XEXP (x
, 1), 1))
5919 && exact_log2 (-UINTVAL (XEXP (XEXP (x
, 1), 1))) >= 0
5920 && rtx_equal_p (XEXP (XEXP (x
, 1), 0), XEXP (x
, 0)))
5921 return simplify_and_const_int (NULL_RTX
, mode
, XEXP (x
, 0),
5922 -INTVAL (XEXP (XEXP (x
, 1), 1)) - 1);
5926 /* If we have (mult (plus A B) C), apply the distributive law and then
5927 the inverse distributive law to see if things simplify. This
5928 occurs mostly in addresses, often when unrolling loops. */
5930 if (GET_CODE (XEXP (x
, 0)) == PLUS
)
5932 rtx result
= distribute_and_simplify_rtx (x
, 0);
5937 /* Try simplify a*(b/c) as (a*b)/c. */
5938 if (FLOAT_MODE_P (mode
) && flag_associative_math
5939 && GET_CODE (XEXP (x
, 0)) == DIV
)
5941 rtx tem
= simplify_binary_operation (MULT
, mode
,
5942 XEXP (XEXP (x
, 0), 0),
5945 return simplify_gen_binary (DIV
, mode
, tem
, XEXP (XEXP (x
, 0), 1));
5950 /* If this is a divide by a power of two, treat it as a shift if
5951 its first operand is a shift. */
5952 if (CONST_INT_P (XEXP (x
, 1))
5953 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0
5954 && (GET_CODE (XEXP (x
, 0)) == ASHIFT
5955 || GET_CODE (XEXP (x
, 0)) == LSHIFTRT
5956 || GET_CODE (XEXP (x
, 0)) == ASHIFTRT
5957 || GET_CODE (XEXP (x
, 0)) == ROTATE
5958 || GET_CODE (XEXP (x
, 0)) == ROTATERT
))
5959 return simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
, XEXP (x
, 0), i
);
5963 case GT
: case GTU
: case GE
: case GEU
:
5964 case LT
: case LTU
: case LE
: case LEU
:
5965 case UNEQ
: case LTGT
:
5966 case UNGT
: case UNGE
:
5967 case UNLT
: case UNLE
:
5968 case UNORDERED
: case ORDERED
:
5969 /* If the first operand is a condition code, we can't do anything
5971 if (GET_CODE (XEXP (x
, 0)) == COMPARE
5972 || (GET_MODE_CLASS (GET_MODE (XEXP (x
, 0))) != MODE_CC
5973 && ! CC0_P (XEXP (x
, 0))))
5975 rtx op0
= XEXP (x
, 0);
5976 rtx op1
= XEXP (x
, 1);
5977 enum rtx_code new_code
;
5979 if (GET_CODE (op0
) == COMPARE
)
5980 op1
= XEXP (op0
, 1), op0
= XEXP (op0
, 0);
5982 /* Simplify our comparison, if possible. */
5983 new_code
= simplify_comparison (code
, &op0
, &op1
);
5985 /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X
5986 if only the low-order bit is possibly nonzero in X (such as when
5987 X is a ZERO_EXTRACT of one bit). Similarly, we can convert EQ to
5988 (xor X 1) or (minus 1 X); we use the former. Finally, if X is
5989 known to be either 0 or -1, NE becomes a NEG and EQ becomes
5992 Remove any ZERO_EXTRACT we made when thinking this was a
5993 comparison. It may now be simpler to use, e.g., an AND. If a
5994 ZERO_EXTRACT is indeed appropriate, it will be placed back by
5995 the call to make_compound_operation in the SET case.
5997 Don't apply these optimizations if the caller would
5998 prefer a comparison rather than a value.
5999 E.g., for the condition in an IF_THEN_ELSE most targets need
6000 an explicit comparison. */
6005 else if (STORE_FLAG_VALUE
== 1
6006 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6007 && op1
== const0_rtx
6008 && mode
== GET_MODE (op0
)
6009 && nonzero_bits (op0
, mode
) == 1)
6010 return gen_lowpart (mode
,
6011 expand_compound_operation (op0
));
6013 else if (STORE_FLAG_VALUE
== 1
6014 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6015 && op1
== const0_rtx
6016 && mode
== GET_MODE (op0
)
6017 && (num_sign_bit_copies (op0
, mode
)
6018 == GET_MODE_PRECISION (mode
)))
6020 op0
= expand_compound_operation (op0
);
6021 return simplify_gen_unary (NEG
, mode
,
6022 gen_lowpart (mode
, op0
),
6026 else if (STORE_FLAG_VALUE
== 1
6027 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6028 && op1
== const0_rtx
6029 && mode
== GET_MODE (op0
)
6030 && nonzero_bits (op0
, mode
) == 1)
6032 op0
= expand_compound_operation (op0
);
6033 return simplify_gen_binary (XOR
, mode
,
6034 gen_lowpart (mode
, op0
),
6038 else if (STORE_FLAG_VALUE
== 1
6039 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6040 && op1
== const0_rtx
6041 && mode
== GET_MODE (op0
)
6042 && (num_sign_bit_copies (op0
, mode
)
6043 == GET_MODE_PRECISION (mode
)))
6045 op0
= expand_compound_operation (op0
);
6046 return plus_constant (mode
, gen_lowpart (mode
, op0
), 1);
6049 /* If STORE_FLAG_VALUE is -1, we have cases similar to
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 && (num_sign_bit_copies (op0
, mode
)
6059 == GET_MODE_PRECISION (mode
)))
6060 return gen_lowpart (mode
,
6061 expand_compound_operation (op0
));
6063 else if (STORE_FLAG_VALUE
== -1
6064 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6065 && op1
== const0_rtx
6066 && mode
== GET_MODE (op0
)
6067 && nonzero_bits (op0
, mode
) == 1)
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 && (num_sign_bit_copies (op0
, mode
)
6080 == GET_MODE_PRECISION (mode
)))
6082 op0
= expand_compound_operation (op0
);
6083 return simplify_gen_unary (NOT
, mode
,
6084 gen_lowpart (mode
, op0
),
6088 /* If X is 0/1, (eq X 0) is X-1. */
6089 else if (STORE_FLAG_VALUE
== -1
6090 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
6091 && op1
== const0_rtx
6092 && mode
== GET_MODE (op0
)
6093 && nonzero_bits (op0
, mode
) == 1)
6095 op0
= expand_compound_operation (op0
);
6096 return plus_constant (mode
, gen_lowpart (mode
, op0
), -1);
6099 /* If STORE_FLAG_VALUE says to just test the sign bit and X has just
6100 one bit that might be nonzero, we can convert (ne x 0) to
6101 (ashift x c) where C puts the bit in the sign bit. Remove any
6102 AND with STORE_FLAG_VALUE when we are done, since we are only
6103 going to test the sign bit. */
6104 if (new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
6105 && HWI_COMPUTABLE_MODE_P (mode
)
6106 && val_signbit_p (mode
, STORE_FLAG_VALUE
)
6107 && op1
== const0_rtx
6108 && mode
== GET_MODE (op0
)
6109 && (i
= exact_log2 (nonzero_bits (op0
, mode
))) >= 0)
6111 x
= simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
6112 expand_compound_operation (op0
),
6113 GET_MODE_PRECISION (mode
) - 1 - i
);
6114 if (GET_CODE (x
) == AND
&& XEXP (x
, 1) == const_true_rtx
)
6120 /* If the code changed, return a whole new comparison.
6121 We also need to avoid using SUBST in cases where
6122 simplify_comparison has widened a comparison with a CONST_INT,
6123 since in that case the wider CONST_INT may fail the sanity
6124 checks in do_SUBST. */
6125 if (new_code
!= code
6126 || (CONST_INT_P (op1
)
6127 && GET_MODE (op0
) != GET_MODE (XEXP (x
, 0))
6128 && GET_MODE (op0
) != GET_MODE (XEXP (x
, 1))))
6129 return gen_rtx_fmt_ee (new_code
, mode
, op0
, op1
);
6131 /* Otherwise, keep this operation, but maybe change its operands.
6132 This also converts (ne (compare FOO BAR) 0) to (ne FOO BAR). */
6133 SUBST (XEXP (x
, 0), op0
);
6134 SUBST (XEXP (x
, 1), op1
);
6139 return simplify_if_then_else (x
);
6145 /* If we are processing SET_DEST, we are done. */
6149 return expand_compound_operation (x
);
6152 return simplify_set (x
);
6156 return simplify_logical (x
);
6163 /* If this is a shift by a constant amount, simplify it. */
6164 if (CONST_INT_P (XEXP (x
, 1)))
6165 return simplify_shift_const (x
, code
, mode
, XEXP (x
, 0),
6166 INTVAL (XEXP (x
, 1)));
6168 else if (SHIFT_COUNT_TRUNCATED
&& !REG_P (XEXP (x
, 1)))
6170 force_to_mode (XEXP (x
, 1), GET_MODE (XEXP (x
, 1)),
6171 ((unsigned HOST_WIDE_INT
) 1
6172 << exact_log2 (GET_MODE_BITSIZE (GET_MODE (x
))))
6184 /* Simplify X, an IF_THEN_ELSE expression. Return the new expression. */
6187 simplify_if_then_else (rtx x
)
6189 machine_mode mode
= GET_MODE (x
);
6190 rtx cond
= XEXP (x
, 0);
6191 rtx true_rtx
= XEXP (x
, 1);
6192 rtx false_rtx
= XEXP (x
, 2);
6193 enum rtx_code true_code
= GET_CODE (cond
);
6194 int comparison_p
= COMPARISON_P (cond
);
6197 enum rtx_code false_code
;
6200 /* Simplify storing of the truth value. */
6201 if (comparison_p
&& true_rtx
== const_true_rtx
&& false_rtx
== const0_rtx
)
6202 return simplify_gen_relational (true_code
, mode
, VOIDmode
,
6203 XEXP (cond
, 0), XEXP (cond
, 1));
6205 /* Also when the truth value has to be reversed. */
6207 && true_rtx
== const0_rtx
&& false_rtx
== const_true_rtx
6208 && (reversed
= reversed_comparison (cond
, mode
)))
6211 /* Sometimes we can simplify the arm of an IF_THEN_ELSE if a register used
6212 in it is being compared against certain values. Get the true and false
6213 comparisons and see if that says anything about the value of each arm. */
6216 && ((false_code
= reversed_comparison_code (cond
, NULL
))
6218 && REG_P (XEXP (cond
, 0)))
6221 rtx from
= XEXP (cond
, 0);
6222 rtx true_val
= XEXP (cond
, 1);
6223 rtx false_val
= true_val
;
6226 /* If FALSE_CODE is EQ, swap the codes and arms. */
6228 if (false_code
== EQ
)
6230 swapped
= 1, true_code
= EQ
, false_code
= NE
;
6231 std::swap (true_rtx
, false_rtx
);
6234 /* If we are comparing against zero and the expression being tested has
6235 only a single bit that might be nonzero, that is its value when it is
6236 not equal to zero. Similarly if it is known to be -1 or 0. */
6238 if (true_code
== EQ
&& true_val
== const0_rtx
6239 && exact_log2 (nzb
= nonzero_bits (from
, GET_MODE (from
))) >= 0)
6242 false_val
= gen_int_mode (nzb
, GET_MODE (from
));
6244 else if (true_code
== EQ
&& true_val
== const0_rtx
6245 && (num_sign_bit_copies (from
, GET_MODE (from
))
6246 == GET_MODE_PRECISION (GET_MODE (from
))))
6249 false_val
= constm1_rtx
;
6252 /* Now simplify an arm if we know the value of the register in the
6253 branch and it is used in the arm. Be careful due to the potential
6254 of locally-shared RTL. */
6256 if (reg_mentioned_p (from
, true_rtx
))
6257 true_rtx
= subst (known_cond (copy_rtx (true_rtx
), true_code
,
6259 pc_rtx
, pc_rtx
, 0, 0, 0);
6260 if (reg_mentioned_p (from
, false_rtx
))
6261 false_rtx
= subst (known_cond (copy_rtx (false_rtx
), false_code
,
6263 pc_rtx
, pc_rtx
, 0, 0, 0);
6265 SUBST (XEXP (x
, 1), swapped
? false_rtx
: true_rtx
);
6266 SUBST (XEXP (x
, 2), swapped
? true_rtx
: false_rtx
);
6268 true_rtx
= XEXP (x
, 1);
6269 false_rtx
= XEXP (x
, 2);
6270 true_code
= GET_CODE (cond
);
6273 /* If we have (if_then_else FOO (pc) (label_ref BAR)) and FOO can be
6274 reversed, do so to avoid needing two sets of patterns for
6275 subtract-and-branch insns. Similarly if we have a constant in the true
6276 arm, the false arm is the same as the first operand of the comparison, or
6277 the false arm is more complicated than the true arm. */
6280 && reversed_comparison_code (cond
, NULL
) != UNKNOWN
6281 && (true_rtx
== pc_rtx
6282 || (CONSTANT_P (true_rtx
)
6283 && !CONST_INT_P (false_rtx
) && false_rtx
!= pc_rtx
)
6284 || true_rtx
== const0_rtx
6285 || (OBJECT_P (true_rtx
) && !OBJECT_P (false_rtx
))
6286 || (GET_CODE (true_rtx
) == SUBREG
&& OBJECT_P (SUBREG_REG (true_rtx
))
6287 && !OBJECT_P (false_rtx
))
6288 || reg_mentioned_p (true_rtx
, false_rtx
)
6289 || rtx_equal_p (false_rtx
, XEXP (cond
, 0))))
6291 true_code
= reversed_comparison_code (cond
, NULL
);
6292 SUBST (XEXP (x
, 0), reversed_comparison (cond
, GET_MODE (cond
)));
6293 SUBST (XEXP (x
, 1), false_rtx
);
6294 SUBST (XEXP (x
, 2), true_rtx
);
6296 std::swap (true_rtx
, false_rtx
);
6299 /* It is possible that the conditional has been simplified out. */
6300 true_code
= GET_CODE (cond
);
6301 comparison_p
= COMPARISON_P (cond
);
6304 /* If the two arms are identical, we don't need the comparison. */
6306 if (rtx_equal_p (true_rtx
, false_rtx
) && ! side_effects_p (cond
))
6309 /* Convert a == b ? b : a to "a". */
6310 if (true_code
== EQ
&& ! side_effects_p (cond
)
6311 && !HONOR_NANS (mode
)
6312 && rtx_equal_p (XEXP (cond
, 0), false_rtx
)
6313 && rtx_equal_p (XEXP (cond
, 1), true_rtx
))
6315 else if (true_code
== NE
&& ! side_effects_p (cond
)
6316 && !HONOR_NANS (mode
)
6317 && rtx_equal_p (XEXP (cond
, 0), true_rtx
)
6318 && rtx_equal_p (XEXP (cond
, 1), false_rtx
))
6321 /* Look for cases where we have (abs x) or (neg (abs X)). */
6323 if (GET_MODE_CLASS (mode
) == MODE_INT
6325 && XEXP (cond
, 1) == const0_rtx
6326 && GET_CODE (false_rtx
) == NEG
6327 && rtx_equal_p (true_rtx
, XEXP (false_rtx
, 0))
6328 && rtx_equal_p (true_rtx
, XEXP (cond
, 0))
6329 && ! side_effects_p (true_rtx
))
6334 return simplify_gen_unary (ABS
, mode
, true_rtx
, mode
);
6338 simplify_gen_unary (NEG
, mode
,
6339 simplify_gen_unary (ABS
, mode
, true_rtx
, mode
),
6345 /* Look for MIN or MAX. */
6347 if ((! FLOAT_MODE_P (mode
) || flag_unsafe_math_optimizations
)
6349 && rtx_equal_p (XEXP (cond
, 0), true_rtx
)
6350 && rtx_equal_p (XEXP (cond
, 1), false_rtx
)
6351 && ! side_effects_p (cond
))
6356 return simplify_gen_binary (SMAX
, mode
, true_rtx
, false_rtx
);
6359 return simplify_gen_binary (SMIN
, mode
, true_rtx
, false_rtx
);
6362 return simplify_gen_binary (UMAX
, mode
, true_rtx
, false_rtx
);
6365 return simplify_gen_binary (UMIN
, mode
, true_rtx
, false_rtx
);
6370 /* If we have (if_then_else COND (OP Z C1) Z) and OP is an identity when its
6371 second operand is zero, this can be done as (OP Z (mult COND C2)) where
6372 C2 = C1 * STORE_FLAG_VALUE. Similarly if OP has an outer ZERO_EXTEND or
6373 SIGN_EXTEND as long as Z is already extended (so we don't destroy it).
6374 We can do this kind of thing in some cases when STORE_FLAG_VALUE is
6375 neither 1 or -1, but it isn't worth checking for. */
6377 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
6379 && GET_MODE_CLASS (mode
) == MODE_INT
6380 && ! side_effects_p (x
))
6382 rtx t
= make_compound_operation (true_rtx
, SET
);
6383 rtx f
= make_compound_operation (false_rtx
, SET
);
6384 rtx cond_op0
= XEXP (cond
, 0);
6385 rtx cond_op1
= XEXP (cond
, 1);
6386 enum rtx_code op
= UNKNOWN
, extend_op
= UNKNOWN
;
6387 machine_mode m
= mode
;
6388 rtx z
= 0, c1
= NULL_RTX
;
6390 if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == MINUS
6391 || GET_CODE (t
) == IOR
|| GET_CODE (t
) == XOR
6392 || GET_CODE (t
) == ASHIFT
6393 || GET_CODE (t
) == LSHIFTRT
|| GET_CODE (t
) == ASHIFTRT
)
6394 && rtx_equal_p (XEXP (t
, 0), f
))
6395 c1
= XEXP (t
, 1), op
= GET_CODE (t
), z
= f
;
6397 /* If an identity-zero op is commutative, check whether there
6398 would be a match if we swapped the operands. */
6399 else if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == IOR
6400 || GET_CODE (t
) == XOR
)
6401 && rtx_equal_p (XEXP (t
, 1), f
))
6402 c1
= XEXP (t
, 0), op
= GET_CODE (t
), z
= f
;
6403 else if (GET_CODE (t
) == SIGN_EXTEND
6404 && (GET_CODE (XEXP (t
, 0)) == PLUS
6405 || GET_CODE (XEXP (t
, 0)) == MINUS
6406 || GET_CODE (XEXP (t
, 0)) == IOR
6407 || GET_CODE (XEXP (t
, 0)) == XOR
6408 || GET_CODE (XEXP (t
, 0)) == ASHIFT
6409 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
6410 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
6411 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
6412 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
6413 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
6414 && (num_sign_bit_copies (f
, GET_MODE (f
))
6416 (GET_MODE_PRECISION (mode
)
6417 - GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (t
, 0), 0))))))
6419 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6420 extend_op
= SIGN_EXTEND
;
6421 m
= GET_MODE (XEXP (t
, 0));
6423 else if (GET_CODE (t
) == SIGN_EXTEND
6424 && (GET_CODE (XEXP (t
, 0)) == PLUS
6425 || GET_CODE (XEXP (t
, 0)) == IOR
6426 || GET_CODE (XEXP (t
, 0)) == XOR
)
6427 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
6428 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
6429 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
6430 && (num_sign_bit_copies (f
, GET_MODE (f
))
6432 (GET_MODE_PRECISION (mode
)
6433 - GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (t
, 0), 1))))))
6435 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6436 extend_op
= SIGN_EXTEND
;
6437 m
= GET_MODE (XEXP (t
, 0));
6439 else if (GET_CODE (t
) == ZERO_EXTEND
6440 && (GET_CODE (XEXP (t
, 0)) == PLUS
6441 || GET_CODE (XEXP (t
, 0)) == MINUS
6442 || GET_CODE (XEXP (t
, 0)) == IOR
6443 || GET_CODE (XEXP (t
, 0)) == XOR
6444 || GET_CODE (XEXP (t
, 0)) == ASHIFT
6445 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
6446 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
6447 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
6448 && HWI_COMPUTABLE_MODE_P (mode
)
6449 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
6450 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
6451 && ((nonzero_bits (f
, GET_MODE (f
))
6452 & ~GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 0))))
6455 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6456 extend_op
= ZERO_EXTEND
;
6457 m
= GET_MODE (XEXP (t
, 0));
6459 else if (GET_CODE (t
) == ZERO_EXTEND
6460 && (GET_CODE (XEXP (t
, 0)) == PLUS
6461 || GET_CODE (XEXP (t
, 0)) == IOR
6462 || GET_CODE (XEXP (t
, 0)) == XOR
)
6463 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
6464 && HWI_COMPUTABLE_MODE_P (mode
)
6465 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
6466 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
6467 && ((nonzero_bits (f
, GET_MODE (f
))
6468 & ~GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 1))))
6471 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
6472 extend_op
= ZERO_EXTEND
;
6473 m
= GET_MODE (XEXP (t
, 0));
6478 temp
= subst (simplify_gen_relational (true_code
, m
, VOIDmode
,
6479 cond_op0
, cond_op1
),
6480 pc_rtx
, pc_rtx
, 0, 0, 0);
6481 temp
= simplify_gen_binary (MULT
, m
, temp
,
6482 simplify_gen_binary (MULT
, m
, c1
,
6484 temp
= subst (temp
, pc_rtx
, pc_rtx
, 0, 0, 0);
6485 temp
= simplify_gen_binary (op
, m
, gen_lowpart (m
, z
), temp
);
6487 if (extend_op
!= UNKNOWN
)
6488 temp
= simplify_gen_unary (extend_op
, mode
, temp
, m
);
6494 /* If we have (if_then_else (ne A 0) C1 0) and either A is known to be 0 or
6495 1 and C1 is a single bit or A is known to be 0 or -1 and C1 is the
6496 negation of a single bit, we can convert this operation to a shift. We
6497 can actually do this more generally, but it doesn't seem worth it. */
6499 if (true_code
== NE
&& XEXP (cond
, 1) == const0_rtx
6500 && false_rtx
== const0_rtx
&& CONST_INT_P (true_rtx
)
6501 && ((1 == nonzero_bits (XEXP (cond
, 0), mode
)
6502 && (i
= exact_log2 (UINTVAL (true_rtx
))) >= 0)
6503 || ((num_sign_bit_copies (XEXP (cond
, 0), mode
)
6504 == GET_MODE_PRECISION (mode
))
6505 && (i
= exact_log2 (-UINTVAL (true_rtx
))) >= 0)))
6507 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
6508 gen_lowpart (mode
, XEXP (cond
, 0)), i
);
6510 /* (IF_THEN_ELSE (NE REG 0) (0) (8)) is REG for nonzero_bits (REG) == 8. */
6511 if (true_code
== NE
&& XEXP (cond
, 1) == const0_rtx
6512 && false_rtx
== const0_rtx
&& CONST_INT_P (true_rtx
)
6513 && GET_MODE (XEXP (cond
, 0)) == mode
6514 && (UINTVAL (true_rtx
) & GET_MODE_MASK (mode
))
6515 == nonzero_bits (XEXP (cond
, 0), mode
)
6516 && (i
= exact_log2 (UINTVAL (true_rtx
) & GET_MODE_MASK (mode
))) >= 0)
6517 return XEXP (cond
, 0);
6522 /* Simplify X, a SET expression. Return the new expression. */
6525 simplify_set (rtx x
)
6527 rtx src
= SET_SRC (x
);
6528 rtx dest
= SET_DEST (x
);
6530 = GET_MODE (src
) != VOIDmode
? GET_MODE (src
) : GET_MODE (dest
);
6531 rtx_insn
*other_insn
;
6534 /* (set (pc) (return)) gets written as (return). */
6535 if (GET_CODE (dest
) == PC
&& ANY_RETURN_P (src
))
6538 /* Now that we know for sure which bits of SRC we are using, see if we can
6539 simplify the expression for the object knowing that we only need the
6542 if (GET_MODE_CLASS (mode
) == MODE_INT
&& HWI_COMPUTABLE_MODE_P (mode
))
6544 src
= force_to_mode (src
, mode
, ~(unsigned HOST_WIDE_INT
) 0, 0);
6545 SUBST (SET_SRC (x
), src
);
6548 /* If we are setting CC0 or if the source is a COMPARE, look for the use of
6549 the comparison result and try to simplify it unless we already have used
6550 undobuf.other_insn. */
6551 if ((GET_MODE_CLASS (mode
) == MODE_CC
6552 || GET_CODE (src
) == COMPARE
6554 && (cc_use
= find_single_use (dest
, subst_insn
, &other_insn
)) != 0
6555 && (undobuf
.other_insn
== 0 || other_insn
== undobuf
.other_insn
)
6556 && COMPARISON_P (*cc_use
)
6557 && rtx_equal_p (XEXP (*cc_use
, 0), dest
))
6559 enum rtx_code old_code
= GET_CODE (*cc_use
);
6560 enum rtx_code new_code
;
6562 int other_changed
= 0;
6563 rtx inner_compare
= NULL_RTX
;
6564 machine_mode compare_mode
= GET_MODE (dest
);
6566 if (GET_CODE (src
) == COMPARE
)
6568 op0
= XEXP (src
, 0), op1
= XEXP (src
, 1);
6569 if (GET_CODE (op0
) == COMPARE
&& op1
== const0_rtx
)
6571 inner_compare
= op0
;
6572 op0
= XEXP (inner_compare
, 0), op1
= XEXP (inner_compare
, 1);
6576 op0
= src
, op1
= CONST0_RTX (GET_MODE (src
));
6578 tmp
= simplify_relational_operation (old_code
, compare_mode
, VOIDmode
,
6581 new_code
= old_code
;
6582 else if (!CONSTANT_P (tmp
))
6584 new_code
= GET_CODE (tmp
);
6585 op0
= XEXP (tmp
, 0);
6586 op1
= XEXP (tmp
, 1);
6590 rtx pat
= PATTERN (other_insn
);
6591 undobuf
.other_insn
= other_insn
;
6592 SUBST (*cc_use
, tmp
);
6594 /* Attempt to simplify CC user. */
6595 if (GET_CODE (pat
) == SET
)
6597 rtx new_rtx
= simplify_rtx (SET_SRC (pat
));
6598 if (new_rtx
!= NULL_RTX
)
6599 SUBST (SET_SRC (pat
), new_rtx
);
6602 /* Convert X into a no-op move. */
6603 SUBST (SET_DEST (x
), pc_rtx
);
6604 SUBST (SET_SRC (x
), pc_rtx
);
6608 /* Simplify our comparison, if possible. */
6609 new_code
= simplify_comparison (new_code
, &op0
, &op1
);
6611 #ifdef SELECT_CC_MODE
6612 /* If this machine has CC modes other than CCmode, check to see if we
6613 need to use a different CC mode here. */
6614 if (GET_MODE_CLASS (GET_MODE (op0
)) == MODE_CC
)
6615 compare_mode
= GET_MODE (op0
);
6616 else if (inner_compare
6617 && GET_MODE_CLASS (GET_MODE (inner_compare
)) == MODE_CC
6618 && new_code
== old_code
6619 && op0
== XEXP (inner_compare
, 0)
6620 && op1
== XEXP (inner_compare
, 1))
6621 compare_mode
= GET_MODE (inner_compare
);
6623 compare_mode
= SELECT_CC_MODE (new_code
, op0
, op1
);
6625 /* If the mode changed, we have to change SET_DEST, the mode in the
6626 compare, and the mode in the place SET_DEST is used. If SET_DEST is
6627 a hard register, just build new versions with the proper mode. If it
6628 is a pseudo, we lose unless it is only time we set the pseudo, in
6629 which case we can safely change its mode. */
6630 if (!HAVE_cc0
&& compare_mode
!= GET_MODE (dest
))
6632 if (can_change_dest_mode (dest
, 0, compare_mode
))
6634 unsigned int regno
= REGNO (dest
);
6637 if (regno
< FIRST_PSEUDO_REGISTER
)
6638 new_dest
= gen_rtx_REG (compare_mode
, regno
);
6641 SUBST_MODE (regno_reg_rtx
[regno
], compare_mode
);
6642 new_dest
= regno_reg_rtx
[regno
];
6645 SUBST (SET_DEST (x
), new_dest
);
6646 SUBST (XEXP (*cc_use
, 0), new_dest
);
6652 #endif /* SELECT_CC_MODE */
6654 /* If the code changed, we have to build a new comparison in
6655 undobuf.other_insn. */
6656 if (new_code
!= old_code
)
6658 int other_changed_previously
= other_changed
;
6659 unsigned HOST_WIDE_INT mask
;
6660 rtx old_cc_use
= *cc_use
;
6662 SUBST (*cc_use
, gen_rtx_fmt_ee (new_code
, GET_MODE (*cc_use
),
6666 /* If the only change we made was to change an EQ into an NE or
6667 vice versa, OP0 has only one bit that might be nonzero, and OP1
6668 is zero, check if changing the user of the condition code will
6669 produce a valid insn. If it won't, we can keep the original code
6670 in that insn by surrounding our operation with an XOR. */
6672 if (((old_code
== NE
&& new_code
== EQ
)
6673 || (old_code
== EQ
&& new_code
== NE
))
6674 && ! other_changed_previously
&& op1
== const0_rtx
6675 && HWI_COMPUTABLE_MODE_P (GET_MODE (op0
))
6676 && exact_log2 (mask
= nonzero_bits (op0
, GET_MODE (op0
))) >= 0)
6678 rtx pat
= PATTERN (other_insn
), note
= 0;
6680 if ((recog_for_combine (&pat
, other_insn
, ¬e
) < 0
6681 && ! check_asm_operands (pat
)))
6683 *cc_use
= old_cc_use
;
6686 op0
= simplify_gen_binary (XOR
, GET_MODE (op0
), op0
,
6694 undobuf
.other_insn
= other_insn
;
6696 /* Don't generate a compare of a CC with 0, just use that CC. */
6697 if (GET_MODE (op0
) == compare_mode
&& op1
== const0_rtx
)
6699 SUBST (SET_SRC (x
), op0
);
6702 /* Otherwise, if we didn't previously have the same COMPARE we
6703 want, create it from scratch. */
6704 else if (GET_CODE (src
) != COMPARE
|| GET_MODE (src
) != compare_mode
6705 || XEXP (src
, 0) != op0
|| XEXP (src
, 1) != op1
)
6707 SUBST (SET_SRC (x
), gen_rtx_COMPARE (compare_mode
, op0
, op1
));
6713 /* Get SET_SRC in a form where we have placed back any
6714 compound expressions. Then do the checks below. */
6715 src
= make_compound_operation (src
, SET
);
6716 SUBST (SET_SRC (x
), src
);
6719 /* If we have (set x (subreg:m1 (op:m2 ...) 0)) with OP being some operation,
6720 and X being a REG or (subreg (reg)), we may be able to convert this to
6721 (set (subreg:m2 x) (op)).
6723 We can always do this if M1 is narrower than M2 because that means that
6724 we only care about the low bits of the result.
6726 However, on machines without WORD_REGISTER_OPERATIONS defined, we cannot
6727 perform a narrower operation than requested since the high-order bits will
6728 be undefined. On machine where it is defined, this transformation is safe
6729 as long as M1 and M2 have the same number of words. */
6731 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
)
6732 && !OBJECT_P (SUBREG_REG (src
))
6733 && (((GET_MODE_SIZE (GET_MODE (src
)) + (UNITS_PER_WORD
- 1))
6735 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))
6736 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
))
6737 && (WORD_REGISTER_OPERATIONS
6738 || (GET_MODE_SIZE (GET_MODE (src
))
6739 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))))
6740 #ifdef CANNOT_CHANGE_MODE_CLASS
6741 && ! (REG_P (dest
) && REGNO (dest
) < FIRST_PSEUDO_REGISTER
6742 && REG_CANNOT_CHANGE_MODE_P (REGNO (dest
),
6743 GET_MODE (SUBREG_REG (src
)),
6747 || (GET_CODE (dest
) == SUBREG
6748 && REG_P (SUBREG_REG (dest
)))))
6750 SUBST (SET_DEST (x
),
6751 gen_lowpart (GET_MODE (SUBREG_REG (src
)),
6753 SUBST (SET_SRC (x
), SUBREG_REG (src
));
6755 src
= SET_SRC (x
), dest
= SET_DEST (x
);
6758 /* If we have (set (cc0) (subreg ...)), we try to remove the subreg
6761 && GET_CODE (src
) == SUBREG
6762 && subreg_lowpart_p (src
)
6763 && (GET_MODE_PRECISION (GET_MODE (src
))
6764 < GET_MODE_PRECISION (GET_MODE (SUBREG_REG (src
)))))
6766 rtx inner
= SUBREG_REG (src
);
6767 machine_mode inner_mode
= GET_MODE (inner
);
6769 /* Here we make sure that we don't have a sign bit on. */
6770 if (val_signbit_known_clear_p (GET_MODE (src
),
6771 nonzero_bits (inner
, inner_mode
)))
6773 SUBST (SET_SRC (x
), inner
);
6778 /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with M wider than N, this
6779 would require a paradoxical subreg. Replace the subreg with a
6780 zero_extend to avoid the reload that would otherwise be required. */
6782 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
)
6783 && INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (src
)))
6784 && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src
))) != UNKNOWN
6785 && SUBREG_BYTE (src
) == 0
6786 && paradoxical_subreg_p (src
)
6787 && MEM_P (SUBREG_REG (src
)))
6790 gen_rtx_fmt_e (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src
))),
6791 GET_MODE (src
), SUBREG_REG (src
)));
6796 /* If we don't have a conditional move, SET_SRC is an IF_THEN_ELSE, and we
6797 are comparing an item known to be 0 or -1 against 0, use a logical
6798 operation instead. Check for one of the arms being an IOR of the other
6799 arm with some value. We compute three terms to be IOR'ed together. In
6800 practice, at most two will be nonzero. Then we do the IOR's. */
6802 if (GET_CODE (dest
) != PC
6803 && GET_CODE (src
) == IF_THEN_ELSE
6804 && GET_MODE_CLASS (GET_MODE (src
)) == MODE_INT
6805 && (GET_CODE (XEXP (src
, 0)) == EQ
|| GET_CODE (XEXP (src
, 0)) == NE
)
6806 && XEXP (XEXP (src
, 0), 1) == const0_rtx
6807 && GET_MODE (src
) == GET_MODE (XEXP (XEXP (src
, 0), 0))
6808 && (!HAVE_conditional_move
6809 || ! can_conditionally_move_p (GET_MODE (src
)))
6810 && (num_sign_bit_copies (XEXP (XEXP (src
, 0), 0),
6811 GET_MODE (XEXP (XEXP (src
, 0), 0)))
6812 == GET_MODE_PRECISION (GET_MODE (XEXP (XEXP (src
, 0), 0))))
6813 && ! side_effects_p (src
))
6815 rtx true_rtx
= (GET_CODE (XEXP (src
, 0)) == NE
6816 ? XEXP (src
, 1) : XEXP (src
, 2));
6817 rtx false_rtx
= (GET_CODE (XEXP (src
, 0)) == NE
6818 ? XEXP (src
, 2) : XEXP (src
, 1));
6819 rtx term1
= const0_rtx
, term2
, term3
;
6821 if (GET_CODE (true_rtx
) == IOR
6822 && rtx_equal_p (XEXP (true_rtx
, 0), false_rtx
))
6823 term1
= false_rtx
, true_rtx
= XEXP (true_rtx
, 1), false_rtx
= const0_rtx
;
6824 else if (GET_CODE (true_rtx
) == IOR
6825 && rtx_equal_p (XEXP (true_rtx
, 1), false_rtx
))
6826 term1
= false_rtx
, true_rtx
= XEXP (true_rtx
, 0), false_rtx
= const0_rtx
;
6827 else if (GET_CODE (false_rtx
) == IOR
6828 && rtx_equal_p (XEXP (false_rtx
, 0), true_rtx
))
6829 term1
= true_rtx
, false_rtx
= XEXP (false_rtx
, 1), true_rtx
= const0_rtx
;
6830 else if (GET_CODE (false_rtx
) == IOR
6831 && rtx_equal_p (XEXP (false_rtx
, 1), true_rtx
))
6832 term1
= true_rtx
, false_rtx
= XEXP (false_rtx
, 0), true_rtx
= const0_rtx
;
6834 term2
= simplify_gen_binary (AND
, GET_MODE (src
),
6835 XEXP (XEXP (src
, 0), 0), true_rtx
);
6836 term3
= simplify_gen_binary (AND
, GET_MODE (src
),
6837 simplify_gen_unary (NOT
, GET_MODE (src
),
6838 XEXP (XEXP (src
, 0), 0),
6843 simplify_gen_binary (IOR
, GET_MODE (src
),
6844 simplify_gen_binary (IOR
, GET_MODE (src
),
6851 /* If either SRC or DEST is a CLOBBER of (const_int 0), make this
6852 whole thing fail. */
6853 if (GET_CODE (src
) == CLOBBER
&& XEXP (src
, 0) == const0_rtx
)
6855 else if (GET_CODE (dest
) == CLOBBER
&& XEXP (dest
, 0) == const0_rtx
)
6858 /* Convert this into a field assignment operation, if possible. */
6859 return make_field_assignment (x
);
6862 /* Simplify, X, and AND, IOR, or XOR operation, and return the simplified
6866 simplify_logical (rtx x
)
6868 machine_mode mode
= GET_MODE (x
);
6869 rtx op0
= XEXP (x
, 0);
6870 rtx op1
= XEXP (x
, 1);
6872 switch (GET_CODE (x
))
6875 /* We can call simplify_and_const_int only if we don't lose
6876 any (sign) bits when converting INTVAL (op1) to
6877 "unsigned HOST_WIDE_INT". */
6878 if (CONST_INT_P (op1
)
6879 && (HWI_COMPUTABLE_MODE_P (mode
)
6880 || INTVAL (op1
) > 0))
6882 x
= simplify_and_const_int (x
, mode
, op0
, INTVAL (op1
));
6883 if (GET_CODE (x
) != AND
)
6890 /* If we have any of (and (ior A B) C) or (and (xor A B) C),
6891 apply the distributive law and then the inverse distributive
6892 law to see if things simplify. */
6893 if (GET_CODE (op0
) == IOR
|| GET_CODE (op0
) == XOR
)
6895 rtx result
= distribute_and_simplify_rtx (x
, 0);
6899 if (GET_CODE (op1
) == IOR
|| GET_CODE (op1
) == XOR
)
6901 rtx result
= distribute_and_simplify_rtx (x
, 1);
6908 /* If we have (ior (and A B) C), apply the distributive law and then
6909 the inverse distributive law to see if things simplify. */
6911 if (GET_CODE (op0
) == AND
)
6913 rtx result
= distribute_and_simplify_rtx (x
, 0);
6918 if (GET_CODE (op1
) == AND
)
6920 rtx result
= distribute_and_simplify_rtx (x
, 1);
6933 /* We consider ZERO_EXTRACT, SIGN_EXTRACT, and SIGN_EXTEND as "compound
6934 operations" because they can be replaced with two more basic operations.
6935 ZERO_EXTEND is also considered "compound" because it can be replaced with
6936 an AND operation, which is simpler, though only one operation.
6938 The function expand_compound_operation is called with an rtx expression
6939 and will convert it to the appropriate shifts and AND operations,
6940 simplifying at each stage.
6942 The function make_compound_operation is called to convert an expression
6943 consisting of shifts and ANDs into the equivalent compound expression.
6944 It is the inverse of this function, loosely speaking. */
6947 expand_compound_operation (rtx x
)
6949 unsigned HOST_WIDE_INT pos
= 0, len
;
6951 unsigned int modewidth
;
6954 switch (GET_CODE (x
))
6959 /* We can't necessarily use a const_int for a multiword mode;
6960 it depends on implicitly extending the value.
6961 Since we don't know the right way to extend it,
6962 we can't tell whether the implicit way is right.
6964 Even for a mode that is no wider than a const_int,
6965 we can't win, because we need to sign extend one of its bits through
6966 the rest of it, and we don't know which bit. */
6967 if (CONST_INT_P (XEXP (x
, 0)))
6970 /* Return if (subreg:MODE FROM 0) is not a safe replacement for
6971 (zero_extend:MODE FROM) or (sign_extend:MODE FROM). It is for any MEM
6972 because (SUBREG (MEM...)) is guaranteed to cause the MEM to be
6973 reloaded. If not for that, MEM's would very rarely be safe.
6975 Reject MODEs bigger than a word, because we might not be able
6976 to reference a two-register group starting with an arbitrary register
6977 (and currently gen_lowpart might crash for a SUBREG). */
6979 if (GET_MODE_SIZE (GET_MODE (XEXP (x
, 0))) > UNITS_PER_WORD
)
6982 /* Reject MODEs that aren't scalar integers because turning vector
6983 or complex modes into shifts causes problems. */
6985 if (! SCALAR_INT_MODE_P (GET_MODE (XEXP (x
, 0))))
6988 len
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)));
6989 /* If the inner object has VOIDmode (the only way this can happen
6990 is if it is an ASM_OPERANDS), we can't do anything since we don't
6991 know how much masking to do. */
7000 /* ... fall through ... */
7003 /* If the operand is a CLOBBER, just return it. */
7004 if (GET_CODE (XEXP (x
, 0)) == CLOBBER
)
7007 if (!CONST_INT_P (XEXP (x
, 1))
7008 || !CONST_INT_P (XEXP (x
, 2))
7009 || GET_MODE (XEXP (x
, 0)) == VOIDmode
)
7012 /* Reject MODEs that aren't scalar integers because turning vector
7013 or complex modes into shifts causes problems. */
7015 if (! SCALAR_INT_MODE_P (GET_MODE (XEXP (x
, 0))))
7018 len
= INTVAL (XEXP (x
, 1));
7019 pos
= INTVAL (XEXP (x
, 2));
7021 /* This should stay within the object being extracted, fail otherwise. */
7022 if (len
+ pos
> GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0))))
7025 if (BITS_BIG_ENDIAN
)
7026 pos
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0))) - len
- pos
;
7033 /* Convert sign extension to zero extension, if we know that the high
7034 bit is not set, as this is easier to optimize. It will be converted
7035 back to cheaper alternative in make_extraction. */
7036 if (GET_CODE (x
) == SIGN_EXTEND
7037 && (HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7038 && ((nonzero_bits (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
7039 & ~(((unsigned HOST_WIDE_INT
)
7040 GET_MODE_MASK (GET_MODE (XEXP (x
, 0))))
7044 machine_mode mode
= GET_MODE (x
);
7045 rtx temp
= gen_rtx_ZERO_EXTEND (mode
, XEXP (x
, 0));
7046 rtx temp2
= expand_compound_operation (temp
);
7048 /* Make sure this is a profitable operation. */
7049 if (set_src_cost (x
, mode
, optimize_this_for_speed_p
)
7050 > set_src_cost (temp2
, mode
, optimize_this_for_speed_p
))
7052 else if (set_src_cost (x
, mode
, optimize_this_for_speed_p
)
7053 > set_src_cost (temp
, mode
, optimize_this_for_speed_p
))
7059 /* We can optimize some special cases of ZERO_EXTEND. */
7060 if (GET_CODE (x
) == ZERO_EXTEND
)
7062 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI if we
7063 know that the last value didn't have any inappropriate bits
7065 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
7066 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
7067 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7068 && (nonzero_bits (XEXP (XEXP (x
, 0), 0), GET_MODE (x
))
7069 & ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7070 return XEXP (XEXP (x
, 0), 0);
7072 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
7073 if (GET_CODE (XEXP (x
, 0)) == SUBREG
7074 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
7075 && subreg_lowpart_p (XEXP (x
, 0))
7076 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
))
7077 && (nonzero_bits (SUBREG_REG (XEXP (x
, 0)), GET_MODE (x
))
7078 & ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7079 return SUBREG_REG (XEXP (x
, 0));
7081 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI when foo
7082 is a comparison and STORE_FLAG_VALUE permits. This is like
7083 the first case, but it works even when GET_MODE (x) is larger
7084 than HOST_WIDE_INT. */
7085 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
7086 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
7087 && COMPARISON_P (XEXP (XEXP (x
, 0), 0))
7088 && (GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)))
7089 <= HOST_BITS_PER_WIDE_INT
)
7090 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7091 return XEXP (XEXP (x
, 0), 0);
7093 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
7094 if (GET_CODE (XEXP (x
, 0)) == SUBREG
7095 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
7096 && subreg_lowpart_p (XEXP (x
, 0))
7097 && COMPARISON_P (SUBREG_REG (XEXP (x
, 0)))
7098 && (GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)))
7099 <= HOST_BITS_PER_WIDE_INT
)
7100 && (STORE_FLAG_VALUE
& ~GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
7101 return SUBREG_REG (XEXP (x
, 0));
7105 /* If we reach here, we want to return a pair of shifts. The inner
7106 shift is a left shift of BITSIZE - POS - LEN bits. The outer
7107 shift is a right shift of BITSIZE - LEN bits. It is arithmetic or
7108 logical depending on the value of UNSIGNEDP.
7110 If this was a ZERO_EXTEND or ZERO_EXTRACT, this pair of shifts will be
7111 converted into an AND of a shift.
7113 We must check for the case where the left shift would have a negative
7114 count. This can happen in a case like (x >> 31) & 255 on machines
7115 that can't shift by a constant. On those machines, we would first
7116 combine the shift with the AND to produce a variable-position
7117 extraction. Then the constant of 31 would be substituted in
7118 to produce such a position. */
7120 modewidth
= GET_MODE_PRECISION (GET_MODE (x
));
7121 if (modewidth
>= pos
+ len
)
7123 machine_mode mode
= GET_MODE (x
);
7124 tem
= gen_lowpart (mode
, XEXP (x
, 0));
7125 if (!tem
|| GET_CODE (tem
) == CLOBBER
)
7127 tem
= simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
7128 tem
, modewidth
- pos
- len
);
7129 tem
= simplify_shift_const (NULL_RTX
, unsignedp
? LSHIFTRT
: ASHIFTRT
,
7130 mode
, tem
, modewidth
- len
);
7132 else if (unsignedp
&& len
< HOST_BITS_PER_WIDE_INT
)
7133 tem
= simplify_and_const_int (NULL_RTX
, GET_MODE (x
),
7134 simplify_shift_const (NULL_RTX
, LSHIFTRT
,
7137 ((unsigned HOST_WIDE_INT
) 1 << len
) - 1);
7139 /* Any other cases we can't handle. */
7142 /* If we couldn't do this for some reason, return the original
7144 if (GET_CODE (tem
) == CLOBBER
)
7150 /* X is a SET which contains an assignment of one object into
7151 a part of another (such as a bit-field assignment, STRICT_LOW_PART,
7152 or certain SUBREGS). If possible, convert it into a series of
7155 We half-heartedly support variable positions, but do not at all
7156 support variable lengths. */
7159 expand_field_assignment (const_rtx x
)
7162 rtx pos
; /* Always counts from low bit. */
7164 rtx mask
, cleared
, masked
;
7165 machine_mode compute_mode
;
7167 /* Loop until we find something we can't simplify. */
7170 if (GET_CODE (SET_DEST (x
)) == STRICT_LOW_PART
7171 && GET_CODE (XEXP (SET_DEST (x
), 0)) == SUBREG
)
7173 inner
= SUBREG_REG (XEXP (SET_DEST (x
), 0));
7174 len
= GET_MODE_PRECISION (GET_MODE (XEXP (SET_DEST (x
), 0)));
7175 pos
= GEN_INT (subreg_lsb (XEXP (SET_DEST (x
), 0)));
7177 else if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
7178 && CONST_INT_P (XEXP (SET_DEST (x
), 1)))
7180 inner
= XEXP (SET_DEST (x
), 0);
7181 len
= INTVAL (XEXP (SET_DEST (x
), 1));
7182 pos
= XEXP (SET_DEST (x
), 2);
7184 /* A constant position should stay within the width of INNER. */
7185 if (CONST_INT_P (pos
)
7186 && INTVAL (pos
) + len
> GET_MODE_PRECISION (GET_MODE (inner
)))
7189 if (BITS_BIG_ENDIAN
)
7191 if (CONST_INT_P (pos
))
7192 pos
= GEN_INT (GET_MODE_PRECISION (GET_MODE (inner
)) - len
7194 else if (GET_CODE (pos
) == MINUS
7195 && CONST_INT_P (XEXP (pos
, 1))
7196 && (INTVAL (XEXP (pos
, 1))
7197 == GET_MODE_PRECISION (GET_MODE (inner
)) - len
))
7198 /* If position is ADJUST - X, new position is X. */
7199 pos
= XEXP (pos
, 0);
7202 HOST_WIDE_INT prec
= GET_MODE_PRECISION (GET_MODE (inner
));
7203 pos
= simplify_gen_binary (MINUS
, GET_MODE (pos
),
7204 gen_int_mode (prec
- len
,
7211 /* A SUBREG between two modes that occupy the same numbers of words
7212 can be done by moving the SUBREG to the source. */
7213 else if (GET_CODE (SET_DEST (x
)) == SUBREG
7214 /* We need SUBREGs to compute nonzero_bits properly. */
7215 && nonzero_sign_valid
7216 && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x
)))
7217 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
7218 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x
))))
7219 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)))
7221 x
= gen_rtx_SET (SUBREG_REG (SET_DEST (x
)),
7223 (GET_MODE (SUBREG_REG (SET_DEST (x
))),
7230 while (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
7231 inner
= SUBREG_REG (inner
);
7233 compute_mode
= GET_MODE (inner
);
7235 /* Don't attempt bitwise arithmetic on non scalar integer modes. */
7236 if (! SCALAR_INT_MODE_P (compute_mode
))
7240 /* Don't do anything for vector or complex integral types. */
7241 if (! FLOAT_MODE_P (compute_mode
))
7244 /* Try to find an integral mode to pun with. */
7245 imode
= mode_for_size (GET_MODE_BITSIZE (compute_mode
), MODE_INT
, 0);
7246 if (imode
== BLKmode
)
7249 compute_mode
= imode
;
7250 inner
= gen_lowpart (imode
, inner
);
7253 /* Compute a mask of LEN bits, if we can do this on the host machine. */
7254 if (len
>= HOST_BITS_PER_WIDE_INT
)
7257 /* Don't try to compute in too wide unsupported modes. */
7258 if (!targetm
.scalar_mode_supported_p (compute_mode
))
7261 /* Now compute the equivalent expression. Make a copy of INNER
7262 for the SET_DEST in case it is a MEM into which we will substitute;
7263 we don't want shared RTL in that case. */
7264 mask
= gen_int_mode (((unsigned HOST_WIDE_INT
) 1 << len
) - 1,
7266 cleared
= simplify_gen_binary (AND
, compute_mode
,
7267 simplify_gen_unary (NOT
, compute_mode
,
7268 simplify_gen_binary (ASHIFT
,
7273 masked
= simplify_gen_binary (ASHIFT
, compute_mode
,
7274 simplify_gen_binary (
7276 gen_lowpart (compute_mode
, SET_SRC (x
)),
7280 x
= gen_rtx_SET (copy_rtx (inner
),
7281 simplify_gen_binary (IOR
, compute_mode
,
7288 /* Return an RTX for a reference to LEN bits of INNER. If POS_RTX is nonzero,
7289 it is an RTX that represents the (variable) starting position; otherwise,
7290 POS is the (constant) starting bit position. Both are counted from the LSB.
7292 UNSIGNEDP is nonzero for an unsigned reference and zero for a signed one.
7294 IN_DEST is nonzero if this is a reference in the destination of a SET.
7295 This is used when a ZERO_ or SIGN_EXTRACT isn't needed. If nonzero,
7296 a STRICT_LOW_PART will be used, if zero, ZERO_EXTEND or SIGN_EXTEND will
7299 IN_COMPARE is nonzero if we are in a COMPARE. This means that a
7300 ZERO_EXTRACT should be built even for bits starting at bit 0.
7302 MODE is the desired mode of the result (if IN_DEST == 0).
7304 The result is an RTX for the extraction or NULL_RTX if the target
7308 make_extraction (machine_mode mode
, rtx inner
, HOST_WIDE_INT pos
,
7309 rtx pos_rtx
, unsigned HOST_WIDE_INT len
, int unsignedp
,
7310 int in_dest
, int in_compare
)
7312 /* This mode describes the size of the storage area
7313 to fetch the overall value from. Within that, we
7314 ignore the POS lowest bits, etc. */
7315 machine_mode is_mode
= GET_MODE (inner
);
7316 machine_mode inner_mode
;
7317 machine_mode wanted_inner_mode
;
7318 machine_mode wanted_inner_reg_mode
= word_mode
;
7319 machine_mode pos_mode
= word_mode
;
7320 machine_mode extraction_mode
= word_mode
;
7321 machine_mode tmode
= mode_for_size (len
, MODE_INT
, 1);
7323 rtx orig_pos_rtx
= pos_rtx
;
7324 HOST_WIDE_INT orig_pos
;
7326 if (pos_rtx
&& CONST_INT_P (pos_rtx
))
7327 pos
= INTVAL (pos_rtx
), pos_rtx
= 0;
7329 if (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
7331 /* If going from (subreg:SI (mem:QI ...)) to (mem:QI ...),
7332 consider just the QI as the memory to extract from.
7333 The subreg adds or removes high bits; its mode is
7334 irrelevant to the meaning of this extraction,
7335 since POS and LEN count from the lsb. */
7336 if (MEM_P (SUBREG_REG (inner
)))
7337 is_mode
= GET_MODE (SUBREG_REG (inner
));
7338 inner
= SUBREG_REG (inner
);
7340 else if (GET_CODE (inner
) == ASHIFT
7341 && CONST_INT_P (XEXP (inner
, 1))
7342 && pos_rtx
== 0 && pos
== 0
7343 && len
> UINTVAL (XEXP (inner
, 1)))
7345 /* We're extracting the least significant bits of an rtx
7346 (ashift X (const_int C)), where LEN > C. Extract the
7347 least significant (LEN - C) bits of X, giving an rtx
7348 whose mode is MODE, then shift it left C times. */
7349 new_rtx
= make_extraction (mode
, XEXP (inner
, 0),
7350 0, 0, len
- INTVAL (XEXP (inner
, 1)),
7351 unsignedp
, in_dest
, in_compare
);
7353 return gen_rtx_ASHIFT (mode
, new_rtx
, XEXP (inner
, 1));
7355 else if (GET_CODE (inner
) == TRUNCATE
)
7356 inner
= XEXP (inner
, 0);
7358 inner_mode
= GET_MODE (inner
);
7360 /* See if this can be done without an extraction. We never can if the
7361 width of the field is not the same as that of some integer mode. For
7362 registers, we can only avoid the extraction if the position is at the
7363 low-order bit and this is either not in the destination or we have the
7364 appropriate STRICT_LOW_PART operation available.
7366 For MEM, we can avoid an extract if the field starts on an appropriate
7367 boundary and we can change the mode of the memory reference. */
7369 if (tmode
!= BLKmode
7370 && ((pos_rtx
== 0 && (pos
% BITS_PER_WORD
) == 0
7372 && (inner_mode
== tmode
7374 || TRULY_NOOP_TRUNCATION_MODES_P (tmode
, inner_mode
)
7375 || reg_truncated_to_mode (tmode
, inner
))
7378 && have_insn_for (STRICT_LOW_PART
, tmode
))))
7379 || (MEM_P (inner
) && pos_rtx
== 0
7381 % (STRICT_ALIGNMENT
? GET_MODE_ALIGNMENT (tmode
)
7382 : BITS_PER_UNIT
)) == 0
7383 /* We can't do this if we are widening INNER_MODE (it
7384 may not be aligned, for one thing). */
7385 && GET_MODE_PRECISION (inner_mode
) >= GET_MODE_PRECISION (tmode
)
7386 && (inner_mode
== tmode
7387 || (! mode_dependent_address_p (XEXP (inner
, 0),
7388 MEM_ADDR_SPACE (inner
))
7389 && ! MEM_VOLATILE_P (inner
))))))
7391 /* If INNER is a MEM, make a new MEM that encompasses just the desired
7392 field. If the original and current mode are the same, we need not
7393 adjust the offset. Otherwise, we do if bytes big endian.
7395 If INNER is not a MEM, get a piece consisting of just the field
7396 of interest (in this case POS % BITS_PER_WORD must be 0). */
7400 HOST_WIDE_INT offset
;
7402 /* POS counts from lsb, but make OFFSET count in memory order. */
7403 if (BYTES_BIG_ENDIAN
)
7404 offset
= (GET_MODE_PRECISION (is_mode
) - len
- pos
) / BITS_PER_UNIT
;
7406 offset
= pos
/ BITS_PER_UNIT
;
7408 new_rtx
= adjust_address_nv (inner
, tmode
, offset
);
7410 else if (REG_P (inner
))
7412 if (tmode
!= inner_mode
)
7414 /* We can't call gen_lowpart in a DEST since we
7415 always want a SUBREG (see below) and it would sometimes
7416 return a new hard register. */
7419 HOST_WIDE_INT final_word
= pos
/ BITS_PER_WORD
;
7421 if (WORDS_BIG_ENDIAN
7422 && GET_MODE_SIZE (inner_mode
) > UNITS_PER_WORD
)
7423 final_word
= ((GET_MODE_SIZE (inner_mode
)
7424 - GET_MODE_SIZE (tmode
))
7425 / UNITS_PER_WORD
) - final_word
;
7427 final_word
*= UNITS_PER_WORD
;
7428 if (BYTES_BIG_ENDIAN
&&
7429 GET_MODE_SIZE (inner_mode
) > GET_MODE_SIZE (tmode
))
7430 final_word
+= (GET_MODE_SIZE (inner_mode
)
7431 - GET_MODE_SIZE (tmode
)) % UNITS_PER_WORD
;
7433 /* Avoid creating invalid subregs, for example when
7434 simplifying (x>>32)&255. */
7435 if (!validate_subreg (tmode
, inner_mode
, inner
, final_word
))
7438 new_rtx
= gen_rtx_SUBREG (tmode
, inner
, final_word
);
7441 new_rtx
= gen_lowpart (tmode
, inner
);
7447 new_rtx
= force_to_mode (inner
, tmode
,
7448 len
>= HOST_BITS_PER_WIDE_INT
7449 ? ~(unsigned HOST_WIDE_INT
) 0
7450 : ((unsigned HOST_WIDE_INT
) 1 << len
) - 1,
7453 /* If this extraction is going into the destination of a SET,
7454 make a STRICT_LOW_PART unless we made a MEM. */
7457 return (MEM_P (new_rtx
) ? new_rtx
7458 : (GET_CODE (new_rtx
) != SUBREG
7459 ? gen_rtx_CLOBBER (tmode
, const0_rtx
)
7460 : gen_rtx_STRICT_LOW_PART (VOIDmode
, new_rtx
)));
7465 if (CONST_SCALAR_INT_P (new_rtx
))
7466 return simplify_unary_operation (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
7467 mode
, new_rtx
, tmode
);
7469 /* If we know that no extraneous bits are set, and that the high
7470 bit is not set, convert the extraction to the cheaper of
7471 sign and zero extension, that are equivalent in these cases. */
7472 if (flag_expensive_optimizations
7473 && (HWI_COMPUTABLE_MODE_P (tmode
)
7474 && ((nonzero_bits (new_rtx
, tmode
)
7475 & ~(((unsigned HOST_WIDE_INT
)GET_MODE_MASK (tmode
)) >> 1))
7478 rtx temp
= gen_rtx_ZERO_EXTEND (mode
, new_rtx
);
7479 rtx temp1
= gen_rtx_SIGN_EXTEND (mode
, new_rtx
);
7481 /* Prefer ZERO_EXTENSION, since it gives more information to
7483 if (set_src_cost (temp
, mode
, optimize_this_for_speed_p
)
7484 <= set_src_cost (temp1
, mode
, optimize_this_for_speed_p
))
7489 /* Otherwise, sign- or zero-extend unless we already are in the
7492 return (gen_rtx_fmt_e (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
7496 /* Unless this is a COMPARE or we have a funny memory reference,
7497 don't do anything with zero-extending field extracts starting at
7498 the low-order bit since they are simple AND operations. */
7499 if (pos_rtx
== 0 && pos
== 0 && ! in_dest
7500 && ! in_compare
&& unsignedp
)
7503 /* Unless INNER is not MEM, reject this if we would be spanning bytes or
7504 if the position is not a constant and the length is not 1. In all
7505 other cases, we would only be going outside our object in cases when
7506 an original shift would have been undefined. */
7508 && ((pos_rtx
== 0 && pos
+ len
> GET_MODE_PRECISION (is_mode
))
7509 || (pos_rtx
!= 0 && len
!= 1)))
7512 enum extraction_pattern pattern
= (in_dest
? EP_insv
7513 : unsignedp
? EP_extzv
: EP_extv
);
7515 /* If INNER is not from memory, we want it to have the mode of a register
7516 extraction pattern's structure operand, or word_mode if there is no
7517 such pattern. The same applies to extraction_mode and pos_mode
7518 and their respective operands.
7520 For memory, assume that the desired extraction_mode and pos_mode
7521 are the same as for a register operation, since at present we don't
7522 have named patterns for aligned memory structures. */
7523 struct extraction_insn insn
;
7524 if (get_best_reg_extraction_insn (&insn
, pattern
,
7525 GET_MODE_BITSIZE (inner_mode
), mode
))
7527 wanted_inner_reg_mode
= insn
.struct_mode
;
7528 pos_mode
= insn
.pos_mode
;
7529 extraction_mode
= insn
.field_mode
;
7532 /* Never narrow an object, since that might not be safe. */
7534 if (mode
!= VOIDmode
7535 && GET_MODE_SIZE (extraction_mode
) < GET_MODE_SIZE (mode
))
7536 extraction_mode
= mode
;
7539 wanted_inner_mode
= wanted_inner_reg_mode
;
7542 /* Be careful not to go beyond the extracted object and maintain the
7543 natural alignment of the memory. */
7544 wanted_inner_mode
= smallest_mode_for_size (len
, MODE_INT
);
7545 while (pos
% GET_MODE_BITSIZE (wanted_inner_mode
) + len
7546 > GET_MODE_BITSIZE (wanted_inner_mode
))
7548 wanted_inner_mode
= GET_MODE_WIDER_MODE (wanted_inner_mode
);
7549 gcc_assert (wanted_inner_mode
!= VOIDmode
);
7555 if (BITS_BIG_ENDIAN
)
7557 /* POS is passed as if BITS_BIG_ENDIAN == 0, so we need to convert it to
7558 BITS_BIG_ENDIAN style. If position is constant, compute new
7559 position. Otherwise, build subtraction.
7560 Note that POS is relative to the mode of the original argument.
7561 If it's a MEM we need to recompute POS relative to that.
7562 However, if we're extracting from (or inserting into) a register,
7563 we want to recompute POS relative to wanted_inner_mode. */
7564 int width
= (MEM_P (inner
)
7565 ? GET_MODE_BITSIZE (is_mode
)
7566 : GET_MODE_BITSIZE (wanted_inner_mode
));
7569 pos
= width
- len
- pos
;
7572 = gen_rtx_MINUS (GET_MODE (pos_rtx
),
7573 gen_int_mode (width
- len
, GET_MODE (pos_rtx
)),
7575 /* POS may be less than 0 now, but we check for that below.
7576 Note that it can only be less than 0 if !MEM_P (inner). */
7579 /* If INNER has a wider mode, and this is a constant extraction, try to
7580 make it smaller and adjust the byte to point to the byte containing
7582 if (wanted_inner_mode
!= VOIDmode
7583 && inner_mode
!= wanted_inner_mode
7585 && GET_MODE_SIZE (wanted_inner_mode
) < GET_MODE_SIZE (is_mode
)
7587 && ! mode_dependent_address_p (XEXP (inner
, 0), MEM_ADDR_SPACE (inner
))
7588 && ! MEM_VOLATILE_P (inner
))
7592 /* The computations below will be correct if the machine is big
7593 endian in both bits and bytes or little endian in bits and bytes.
7594 If it is mixed, we must adjust. */
7596 /* If bytes are big endian and we had a paradoxical SUBREG, we must
7597 adjust OFFSET to compensate. */
7598 if (BYTES_BIG_ENDIAN
7599 && GET_MODE_SIZE (inner_mode
) < GET_MODE_SIZE (is_mode
))
7600 offset
-= GET_MODE_SIZE (is_mode
) - GET_MODE_SIZE (inner_mode
);
7602 /* We can now move to the desired byte. */
7603 offset
+= (pos
/ GET_MODE_BITSIZE (wanted_inner_mode
))
7604 * GET_MODE_SIZE (wanted_inner_mode
);
7605 pos
%= GET_MODE_BITSIZE (wanted_inner_mode
);
7607 if (BYTES_BIG_ENDIAN
!= BITS_BIG_ENDIAN
7608 && is_mode
!= wanted_inner_mode
)
7609 offset
= (GET_MODE_SIZE (is_mode
)
7610 - GET_MODE_SIZE (wanted_inner_mode
) - offset
);
7612 inner
= adjust_address_nv (inner
, wanted_inner_mode
, offset
);
7615 /* If INNER is not memory, get it into the proper mode. If we are changing
7616 its mode, POS must be a constant and smaller than the size of the new
7618 else if (!MEM_P (inner
))
7620 /* On the LHS, don't create paradoxical subregs implicitely truncating
7621 the register unless TRULY_NOOP_TRUNCATION. */
7623 && !TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (inner
),
7627 if (GET_MODE (inner
) != wanted_inner_mode
7629 || orig_pos
+ len
> GET_MODE_BITSIZE (wanted_inner_mode
)))
7635 inner
= force_to_mode (inner
, wanted_inner_mode
,
7637 || len
+ orig_pos
>= HOST_BITS_PER_WIDE_INT
7638 ? ~(unsigned HOST_WIDE_INT
) 0
7639 : ((((unsigned HOST_WIDE_INT
) 1 << len
) - 1)
7644 /* Adjust mode of POS_RTX, if needed. If we want a wider mode, we
7645 have to zero extend. Otherwise, we can just use a SUBREG. */
7647 && GET_MODE_SIZE (pos_mode
) > GET_MODE_SIZE (GET_MODE (pos_rtx
)))
7649 rtx temp
= simplify_gen_unary (ZERO_EXTEND
, pos_mode
, pos_rtx
,
7650 GET_MODE (pos_rtx
));
7652 /* If we know that no extraneous bits are set, and that the high
7653 bit is not set, convert extraction to cheaper one - either
7654 SIGN_EXTENSION or ZERO_EXTENSION, that are equivalent in these
7656 if (flag_expensive_optimizations
7657 && (HWI_COMPUTABLE_MODE_P (GET_MODE (pos_rtx
))
7658 && ((nonzero_bits (pos_rtx
, GET_MODE (pos_rtx
))
7659 & ~(((unsigned HOST_WIDE_INT
)
7660 GET_MODE_MASK (GET_MODE (pos_rtx
)))
7664 rtx temp1
= simplify_gen_unary (SIGN_EXTEND
, pos_mode
, pos_rtx
,
7665 GET_MODE (pos_rtx
));
7667 /* Prefer ZERO_EXTENSION, since it gives more information to
7669 if (set_src_cost (temp1
, pos_mode
, optimize_this_for_speed_p
)
7670 < set_src_cost (temp
, pos_mode
, optimize_this_for_speed_p
))
7676 /* Make POS_RTX unless we already have it and it is correct. If we don't
7677 have a POS_RTX but we do have an ORIG_POS_RTX, the latter must
7679 if (pos_rtx
== 0 && orig_pos_rtx
!= 0 && INTVAL (orig_pos_rtx
) == pos
)
7680 pos_rtx
= orig_pos_rtx
;
7682 else if (pos_rtx
== 0)
7683 pos_rtx
= GEN_INT (pos
);
7685 /* Make the required operation. See if we can use existing rtx. */
7686 new_rtx
= gen_rtx_fmt_eee (unsignedp
? ZERO_EXTRACT
: SIGN_EXTRACT
,
7687 extraction_mode
, inner
, GEN_INT (len
), pos_rtx
);
7689 new_rtx
= gen_lowpart (mode
, new_rtx
);
7694 /* See if X contains an ASHIFT of COUNT or more bits that can be commuted
7695 with any other operations in X. Return X without that shift if so. */
7698 extract_left_shift (rtx x
, int count
)
7700 enum rtx_code code
= GET_CODE (x
);
7701 machine_mode mode
= GET_MODE (x
);
7707 /* This is the shift itself. If it is wide enough, we will return
7708 either the value being shifted if the shift count is equal to
7709 COUNT or a shift for the difference. */
7710 if (CONST_INT_P (XEXP (x
, 1))
7711 && INTVAL (XEXP (x
, 1)) >= count
)
7712 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (x
, 0),
7713 INTVAL (XEXP (x
, 1)) - count
);
7717 if ((tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
7718 return simplify_gen_unary (code
, mode
, tem
, mode
);
7722 case PLUS
: case IOR
: case XOR
: case AND
:
7723 /* If we can safely shift this constant and we find the inner shift,
7724 make a new operation. */
7725 if (CONST_INT_P (XEXP (x
, 1))
7726 && (UINTVAL (XEXP (x
, 1))
7727 & ((((unsigned HOST_WIDE_INT
) 1 << count
)) - 1)) == 0
7728 && (tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
7730 HOST_WIDE_INT val
= INTVAL (XEXP (x
, 1)) >> count
;
7731 return simplify_gen_binary (code
, mode
, tem
,
7732 gen_int_mode (val
, mode
));
7743 /* Look at the expression rooted at X. Look for expressions
7744 equivalent to ZERO_EXTRACT, SIGN_EXTRACT, ZERO_EXTEND, SIGN_EXTEND.
7745 Form these expressions.
7747 Return the new rtx, usually just X.
7749 Also, for machines like the VAX that don't have logical shift insns,
7750 try to convert logical to arithmetic shift operations in cases where
7751 they are equivalent. This undoes the canonicalizations to logical
7752 shifts done elsewhere.
7754 We try, as much as possible, to re-use rtl expressions to save memory.
7756 IN_CODE says what kind of expression we are processing. Normally, it is
7757 SET. In a memory address it is MEM. When processing the arguments of
7758 a comparison or a COMPARE against zero, it is COMPARE. */
7761 make_compound_operation (rtx x
, enum rtx_code in_code
)
7763 enum rtx_code code
= GET_CODE (x
);
7764 machine_mode mode
= GET_MODE (x
);
7765 int mode_width
= GET_MODE_PRECISION (mode
);
7767 enum rtx_code next_code
;
7773 /* Select the code to be used in recursive calls. Once we are inside an
7774 address, we stay there. If we have a comparison, set to COMPARE,
7775 but once inside, go back to our default of SET. */
7777 next_code
= (code
== MEM
? MEM
7778 : ((code
== COMPARE
|| COMPARISON_P (x
))
7779 && XEXP (x
, 1) == const0_rtx
) ? COMPARE
7780 : in_code
== COMPARE
? SET
: in_code
);
7782 /* Process depending on the code of this operation. If NEW is set
7783 nonzero, it will be returned. */
7788 /* Convert shifts by constants into multiplications if inside
7790 if (in_code
== MEM
&& CONST_INT_P (XEXP (x
, 1))
7791 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
7792 && INTVAL (XEXP (x
, 1)) >= 0
7793 && SCALAR_INT_MODE_P (mode
))
7795 HOST_WIDE_INT count
= INTVAL (XEXP (x
, 1));
7796 HOST_WIDE_INT multval
= (HOST_WIDE_INT
) 1 << count
;
7798 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
7799 if (GET_CODE (new_rtx
) == NEG
)
7801 new_rtx
= XEXP (new_rtx
, 0);
7804 multval
= trunc_int_for_mode (multval
, mode
);
7805 new_rtx
= gen_rtx_MULT (mode
, new_rtx
, gen_int_mode (multval
, mode
));
7812 lhs
= make_compound_operation (lhs
, next_code
);
7813 rhs
= make_compound_operation (rhs
, next_code
);
7814 if (GET_CODE (lhs
) == MULT
&& GET_CODE (XEXP (lhs
, 0)) == NEG
7815 && SCALAR_INT_MODE_P (mode
))
7817 tem
= simplify_gen_binary (MULT
, mode
, XEXP (XEXP (lhs
, 0), 0),
7819 new_rtx
= simplify_gen_binary (MINUS
, mode
, rhs
, tem
);
7821 else if (GET_CODE (lhs
) == MULT
7822 && (CONST_INT_P (XEXP (lhs
, 1)) && INTVAL (XEXP (lhs
, 1)) < 0))
7824 tem
= simplify_gen_binary (MULT
, mode
, XEXP (lhs
, 0),
7825 simplify_gen_unary (NEG
, mode
,
7828 new_rtx
= simplify_gen_binary (MINUS
, mode
, rhs
, tem
);
7832 SUBST (XEXP (x
, 0), lhs
);
7833 SUBST (XEXP (x
, 1), rhs
);
7836 x
= gen_lowpart (mode
, new_rtx
);
7842 lhs
= make_compound_operation (lhs
, next_code
);
7843 rhs
= make_compound_operation (rhs
, next_code
);
7844 if (GET_CODE (rhs
) == MULT
&& GET_CODE (XEXP (rhs
, 0)) == NEG
7845 && SCALAR_INT_MODE_P (mode
))
7847 tem
= simplify_gen_binary (MULT
, mode
, XEXP (XEXP (rhs
, 0), 0),
7849 new_rtx
= simplify_gen_binary (PLUS
, mode
, tem
, lhs
);
7851 else if (GET_CODE (rhs
) == MULT
7852 && (CONST_INT_P (XEXP (rhs
, 1)) && INTVAL (XEXP (rhs
, 1)) < 0))
7854 tem
= simplify_gen_binary (MULT
, mode
, XEXP (rhs
, 0),
7855 simplify_gen_unary (NEG
, mode
,
7858 new_rtx
= simplify_gen_binary (PLUS
, mode
, tem
, lhs
);
7862 SUBST (XEXP (x
, 0), lhs
);
7863 SUBST (XEXP (x
, 1), rhs
);
7866 return gen_lowpart (mode
, new_rtx
);
7869 /* If the second operand is not a constant, we can't do anything
7871 if (!CONST_INT_P (XEXP (x
, 1)))
7874 /* If the constant is a power of two minus one and the first operand
7875 is a logical right shift, make an extraction. */
7876 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
7877 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7879 new_rtx
= make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
7880 new_rtx
= make_extraction (mode
, new_rtx
, 0, XEXP (XEXP (x
, 0), 1), i
, 1,
7881 0, in_code
== COMPARE
);
7884 /* Same as previous, but for (subreg (lshiftrt ...)) in first op. */
7885 else if (GET_CODE (XEXP (x
, 0)) == SUBREG
7886 && subreg_lowpart_p (XEXP (x
, 0))
7887 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == LSHIFTRT
7888 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7890 rtx inner_x0
= SUBREG_REG (XEXP (x
, 0));
7891 machine_mode inner_mode
= GET_MODE (inner_x0
);
7892 new_rtx
= make_compound_operation (XEXP (inner_x0
, 0), next_code
);
7893 new_rtx
= make_extraction (inner_mode
, new_rtx
, 0,
7895 i
, 1, 0, in_code
== COMPARE
);
7899 /* If we narrowed the mode when dropping the subreg, then
7900 we must zero-extend to keep the semantics of the AND. */
7901 if (GET_MODE_SIZE (inner_mode
) >= GET_MODE_SIZE (mode
))
7903 else if (SCALAR_INT_MODE_P (inner_mode
))
7904 new_rtx
= simplify_gen_unary (ZERO_EXTEND
, mode
,
7905 new_rtx
, inner_mode
);
7910 /* If that didn't give anything, see if the AND simplifies on
7912 if (!new_rtx
&& i
>= 0)
7914 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
7915 new_rtx
= make_extraction (mode
, new_rtx
, 0, NULL_RTX
, i
, 1,
7916 0, in_code
== COMPARE
);
7919 /* Same as previous, but for (xor/ior (lshiftrt...) (lshiftrt...)). */
7920 else if ((GET_CODE (XEXP (x
, 0)) == XOR
7921 || GET_CODE (XEXP (x
, 0)) == IOR
)
7922 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == LSHIFTRT
7923 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == LSHIFTRT
7924 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7926 /* Apply the distributive law, and then try to make extractions. */
7927 new_rtx
= gen_rtx_fmt_ee (GET_CODE (XEXP (x
, 0)), mode
,
7928 gen_rtx_AND (mode
, XEXP (XEXP (x
, 0), 0),
7930 gen_rtx_AND (mode
, XEXP (XEXP (x
, 0), 1),
7932 new_rtx
= make_compound_operation (new_rtx
, in_code
);
7935 /* If we are have (and (rotate X C) M) and C is larger than the number
7936 of bits in M, this is an extraction. */
7938 else if (GET_CODE (XEXP (x
, 0)) == ROTATE
7939 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
7940 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0
7941 && i
<= INTVAL (XEXP (XEXP (x
, 0), 1)))
7943 new_rtx
= make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
7944 new_rtx
= make_extraction (mode
, new_rtx
,
7945 (GET_MODE_PRECISION (mode
)
7946 - INTVAL (XEXP (XEXP (x
, 0), 1))),
7947 NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
7950 /* On machines without logical shifts, if the operand of the AND is
7951 a logical shift and our mask turns off all the propagated sign
7952 bits, we can replace the logical shift with an arithmetic shift. */
7953 else if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
7954 && !have_insn_for (LSHIFTRT
, mode
)
7955 && have_insn_for (ASHIFTRT
, mode
)
7956 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
7957 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
7958 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
7959 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
7961 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
7963 mask
>>= INTVAL (XEXP (XEXP (x
, 0), 1));
7964 if ((INTVAL (XEXP (x
, 1)) & ~mask
) == 0)
7966 gen_rtx_ASHIFTRT (mode
,
7967 make_compound_operation
7968 (XEXP (XEXP (x
, 0), 0), next_code
),
7969 XEXP (XEXP (x
, 0), 1)));
7972 /* If the constant is one less than a power of two, this might be
7973 representable by an extraction even if no shift is present.
7974 If it doesn't end up being a ZERO_EXTEND, we will ignore it unless
7975 we are in a COMPARE. */
7976 else if ((i
= exact_log2 (UINTVAL (XEXP (x
, 1)) + 1)) >= 0)
7977 new_rtx
= make_extraction (mode
,
7978 make_compound_operation (XEXP (x
, 0),
7980 0, NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
7982 /* If we are in a comparison and this is an AND with a power of two,
7983 convert this into the appropriate bit extract. */
7984 else if (in_code
== COMPARE
7985 && (i
= exact_log2 (UINTVAL (XEXP (x
, 1)))) >= 0)
7986 new_rtx
= make_extraction (mode
,
7987 make_compound_operation (XEXP (x
, 0),
7989 i
, NULL_RTX
, 1, 1, 0, 1);
7994 /* If the sign bit is known to be zero, replace this with an
7995 arithmetic shift. */
7996 if (have_insn_for (ASHIFTRT
, mode
)
7997 && ! have_insn_for (LSHIFTRT
, mode
)
7998 && mode_width
<= HOST_BITS_PER_WIDE_INT
7999 && (nonzero_bits (XEXP (x
, 0), mode
) & (1 << (mode_width
- 1))) == 0)
8001 new_rtx
= gen_rtx_ASHIFTRT (mode
,
8002 make_compound_operation (XEXP (x
, 0),
8008 /* ... fall through ... */
8014 /* If we have (ashiftrt (ashift foo C1) C2) with C2 >= C1,
8015 this is a SIGN_EXTRACT. */
8016 if (CONST_INT_P (rhs
)
8017 && GET_CODE (lhs
) == ASHIFT
8018 && CONST_INT_P (XEXP (lhs
, 1))
8019 && INTVAL (rhs
) >= INTVAL (XEXP (lhs
, 1))
8020 && INTVAL (XEXP (lhs
, 1)) >= 0
8021 && INTVAL (rhs
) < mode_width
)
8023 new_rtx
= make_compound_operation (XEXP (lhs
, 0), next_code
);
8024 new_rtx
= make_extraction (mode
, new_rtx
,
8025 INTVAL (rhs
) - INTVAL (XEXP (lhs
, 1)),
8026 NULL_RTX
, mode_width
- INTVAL (rhs
),
8027 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
8031 /* See if we have operations between an ASHIFTRT and an ASHIFT.
8032 If so, try to merge the shifts into a SIGN_EXTEND. We could
8033 also do this for some cases of SIGN_EXTRACT, but it doesn't
8034 seem worth the effort; the case checked for occurs on Alpha. */
8037 && ! (GET_CODE (lhs
) == SUBREG
8038 && (OBJECT_P (SUBREG_REG (lhs
))))
8039 && CONST_INT_P (rhs
)
8040 && INTVAL (rhs
) < HOST_BITS_PER_WIDE_INT
8041 && INTVAL (rhs
) < mode_width
8042 && (new_rtx
= extract_left_shift (lhs
, INTVAL (rhs
))) != 0)
8043 new_rtx
= make_extraction (mode
, make_compound_operation (new_rtx
, next_code
),
8044 0, NULL_RTX
, mode_width
- INTVAL (rhs
),
8045 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
8050 /* Call ourselves recursively on the inner expression. If we are
8051 narrowing the object and it has a different RTL code from
8052 what it originally did, do this SUBREG as a force_to_mode. */
8054 rtx inner
= SUBREG_REG (x
), simplified
;
8055 enum rtx_code subreg_code
= in_code
;
8057 /* If in_code is COMPARE, it isn't always safe to pass it through
8058 to the recursive make_compound_operation call. */
8059 if (subreg_code
== COMPARE
8060 && (!subreg_lowpart_p (x
)
8061 || GET_CODE (inner
) == SUBREG
8062 /* (subreg:SI (and:DI (reg:DI) (const_int 0x800000000)) 0)
8063 is (const_int 0), rather than
8064 (subreg:SI (lshiftrt:DI (reg:DI) (const_int 35)) 0). */
8065 || (GET_CODE (inner
) == AND
8066 && CONST_INT_P (XEXP (inner
, 1))
8067 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (inner
))
8068 && exact_log2 (UINTVAL (XEXP (inner
, 1)))
8069 >= GET_MODE_BITSIZE (mode
))))
8072 tem
= make_compound_operation (inner
, subreg_code
);
8075 = simplify_subreg (mode
, tem
, GET_MODE (inner
), SUBREG_BYTE (x
));
8079 if (GET_CODE (tem
) != GET_CODE (inner
)
8080 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (inner
))
8081 && subreg_lowpart_p (x
))
8084 = force_to_mode (tem
, mode
, ~(unsigned HOST_WIDE_INT
) 0, 0);
8086 /* If we have something other than a SUBREG, we might have
8087 done an expansion, so rerun ourselves. */
8088 if (GET_CODE (newer
) != SUBREG
)
8089 newer
= make_compound_operation (newer
, in_code
);
8091 /* force_to_mode can expand compounds. If it just re-expanded the
8092 compound, use gen_lowpart to convert to the desired mode. */
8093 if (rtx_equal_p (newer
, x
)
8094 /* Likewise if it re-expanded the compound only partially.
8095 This happens for SUBREG of ZERO_EXTRACT if they extract
8096 the same number of bits. */
8097 || (GET_CODE (newer
) == SUBREG
8098 && (GET_CODE (SUBREG_REG (newer
)) == LSHIFTRT
8099 || GET_CODE (SUBREG_REG (newer
)) == ASHIFTRT
)
8100 && GET_CODE (inner
) == AND
8101 && rtx_equal_p (SUBREG_REG (newer
), XEXP (inner
, 0))))
8102 return gen_lowpart (GET_MODE (x
), tem
);
8118 x
= gen_lowpart (mode
, new_rtx
);
8119 code
= GET_CODE (x
);
8122 /* Now recursively process each operand of this operation. We need to
8123 handle ZERO_EXTEND specially so that we don't lose track of the
8125 if (GET_CODE (x
) == ZERO_EXTEND
)
8127 new_rtx
= make_compound_operation (XEXP (x
, 0), next_code
);
8128 tem
= simplify_const_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
8129 new_rtx
, GET_MODE (XEXP (x
, 0)));
8132 SUBST (XEXP (x
, 0), new_rtx
);
8136 fmt
= GET_RTX_FORMAT (code
);
8137 for (i
= 0; i
< GET_RTX_LENGTH (code
); i
++)
8140 new_rtx
= make_compound_operation (XEXP (x
, i
), next_code
);
8141 SUBST (XEXP (x
, i
), new_rtx
);
8143 else if (fmt
[i
] == 'E')
8144 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
8146 new_rtx
= make_compound_operation (XVECEXP (x
, i
, j
), next_code
);
8147 SUBST (XVECEXP (x
, i
, j
), new_rtx
);
8151 /* If this is a commutative operation, the changes to the operands
8152 may have made it noncanonical. */
8153 if (COMMUTATIVE_ARITH_P (x
)
8154 && swap_commutative_operands_p (XEXP (x
, 0), XEXP (x
, 1)))
8157 SUBST (XEXP (x
, 0), XEXP (x
, 1));
8158 SUBST (XEXP (x
, 1), tem
);
8164 /* Given M see if it is a value that would select a field of bits
8165 within an item, but not the entire word. Return -1 if not.
8166 Otherwise, return the starting position of the field, where 0 is the
8169 *PLEN is set to the length of the field. */
8172 get_pos_from_mask (unsigned HOST_WIDE_INT m
, unsigned HOST_WIDE_INT
*plen
)
8174 /* Get the bit number of the first 1 bit from the right, -1 if none. */
8175 int pos
= m
? ctz_hwi (m
) : -1;
8179 /* Now shift off the low-order zero bits and see if we have a
8180 power of two minus 1. */
8181 len
= exact_log2 ((m
>> pos
) + 1);
8190 /* If X refers to a register that equals REG in value, replace these
8191 references with REG. */
8193 canon_reg_for_combine (rtx x
, rtx reg
)
8200 enum rtx_code code
= GET_CODE (x
);
8201 switch (GET_RTX_CLASS (code
))
8204 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8205 if (op0
!= XEXP (x
, 0))
8206 return simplify_gen_unary (GET_CODE (x
), GET_MODE (x
), op0
,
8211 case RTX_COMM_ARITH
:
8212 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8213 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8214 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8215 return simplify_gen_binary (GET_CODE (x
), GET_MODE (x
), op0
, op1
);
8219 case RTX_COMM_COMPARE
:
8220 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8221 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8222 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8223 return simplify_gen_relational (GET_CODE (x
), GET_MODE (x
),
8224 GET_MODE (op0
), op0
, op1
);
8228 case RTX_BITFIELD_OPS
:
8229 op0
= canon_reg_for_combine (XEXP (x
, 0), reg
);
8230 op1
= canon_reg_for_combine (XEXP (x
, 1), reg
);
8231 op2
= canon_reg_for_combine (XEXP (x
, 2), reg
);
8232 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1) || op2
!= XEXP (x
, 2))
8233 return simplify_gen_ternary (GET_CODE (x
), GET_MODE (x
),
8234 GET_MODE (op0
), op0
, op1
, op2
);
8239 if (rtx_equal_p (get_last_value (reg
), x
)
8240 || rtx_equal_p (reg
, get_last_value (x
)))
8249 fmt
= GET_RTX_FORMAT (code
);
8251 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
8254 rtx op
= canon_reg_for_combine (XEXP (x
, i
), reg
);
8255 if (op
!= XEXP (x
, i
))
8265 else if (fmt
[i
] == 'E')
8268 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
8270 rtx op
= canon_reg_for_combine (XVECEXP (x
, i
, j
), reg
);
8271 if (op
!= XVECEXP (x
, i
, j
))
8278 XVECEXP (x
, i
, j
) = op
;
8289 /* Return X converted to MODE. If the value is already truncated to
8290 MODE we can just return a subreg even though in the general case we
8291 would need an explicit truncation. */
8294 gen_lowpart_or_truncate (machine_mode mode
, rtx x
)
8296 if (!CONST_INT_P (x
)
8297 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (x
))
8298 && !TRULY_NOOP_TRUNCATION_MODES_P (mode
, GET_MODE (x
))
8299 && !(REG_P (x
) && reg_truncated_to_mode (mode
, x
)))
8301 /* Bit-cast X into an integer mode. */
8302 if (!SCALAR_INT_MODE_P (GET_MODE (x
)))
8303 x
= gen_lowpart (int_mode_for_mode (GET_MODE (x
)), x
);
8304 x
= simplify_gen_unary (TRUNCATE
, int_mode_for_mode (mode
),
8308 return gen_lowpart (mode
, x
);
8311 /* See if X can be simplified knowing that we will only refer to it in
8312 MODE and will only refer to those bits that are nonzero in MASK.
8313 If other bits are being computed or if masking operations are done
8314 that select a superset of the bits in MASK, they can sometimes be
8317 Return a possibly simplified expression, but always convert X to
8318 MODE. If X is a CONST_INT, AND the CONST_INT with MASK.
8320 If JUST_SELECT is nonzero, don't optimize by noticing that bits in MASK
8321 are all off in X. This is used when X will be complemented, by either
8322 NOT, NEG, or XOR. */
8325 force_to_mode (rtx x
, machine_mode mode
, unsigned HOST_WIDE_INT mask
,
8328 enum rtx_code code
= GET_CODE (x
);
8329 int next_select
= just_select
|| code
== XOR
|| code
== NOT
|| code
== NEG
;
8330 machine_mode op_mode
;
8331 unsigned HOST_WIDE_INT fuller_mask
, nonzero
;
8334 /* If this is a CALL or ASM_OPERANDS, don't do anything. Some of the
8335 code below will do the wrong thing since the mode of such an
8336 expression is VOIDmode.
8338 Also do nothing if X is a CLOBBER; this can happen if X was
8339 the return value from a call to gen_lowpart. */
8340 if (code
== CALL
|| code
== ASM_OPERANDS
|| code
== CLOBBER
)
8343 /* We want to perform the operation in its present mode unless we know
8344 that the operation is valid in MODE, in which case we do the operation
8346 op_mode
= ((GET_MODE_CLASS (mode
) == GET_MODE_CLASS (GET_MODE (x
))
8347 && have_insn_for (code
, mode
))
8348 ? mode
: GET_MODE (x
));
8350 /* It is not valid to do a right-shift in a narrower mode
8351 than the one it came in with. */
8352 if ((code
== LSHIFTRT
|| code
== ASHIFTRT
)
8353 && GET_MODE_PRECISION (mode
) < GET_MODE_PRECISION (GET_MODE (x
)))
8354 op_mode
= GET_MODE (x
);
8356 /* Truncate MASK to fit OP_MODE. */
8358 mask
&= GET_MODE_MASK (op_mode
);
8360 /* When we have an arithmetic operation, or a shift whose count we
8361 do not know, we need to assume that all bits up to the highest-order
8362 bit in MASK will be needed. This is how we form such a mask. */
8363 if (mask
& ((unsigned HOST_WIDE_INT
) 1 << (HOST_BITS_PER_WIDE_INT
- 1)))
8364 fuller_mask
= ~(unsigned HOST_WIDE_INT
) 0;
8366 fuller_mask
= (((unsigned HOST_WIDE_INT
) 1 << (floor_log2 (mask
) + 1))
8369 /* Determine what bits of X are guaranteed to be (non)zero. */
8370 nonzero
= nonzero_bits (x
, mode
);
8372 /* If none of the bits in X are needed, return a zero. */
8373 if (!just_select
&& (nonzero
& mask
) == 0 && !side_effects_p (x
))
8376 /* If X is a CONST_INT, return a new one. Do this here since the
8377 test below will fail. */
8378 if (CONST_INT_P (x
))
8380 if (SCALAR_INT_MODE_P (mode
))
8381 return gen_int_mode (INTVAL (x
) & mask
, mode
);
8384 x
= GEN_INT (INTVAL (x
) & mask
);
8385 return gen_lowpart_common (mode
, x
);
8389 /* If X is narrower than MODE and we want all the bits in X's mode, just
8390 get X in the proper mode. */
8391 if (GET_MODE_SIZE (GET_MODE (x
)) < GET_MODE_SIZE (mode
)
8392 && (GET_MODE_MASK (GET_MODE (x
)) & ~mask
) == 0)
8393 return gen_lowpart (mode
, x
);
8395 /* We can ignore the effect of a SUBREG if it narrows the mode or
8396 if the constant masks to zero all the bits the mode doesn't have. */
8397 if (GET_CODE (x
) == SUBREG
8398 && subreg_lowpart_p (x
)
8399 && ((GET_MODE_SIZE (GET_MODE (x
))
8400 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
8402 & GET_MODE_MASK (GET_MODE (x
))
8403 & ~GET_MODE_MASK (GET_MODE (SUBREG_REG (x
)))))))
8404 return force_to_mode (SUBREG_REG (x
), mode
, mask
, next_select
);
8406 /* The arithmetic simplifications here only work for scalar integer modes. */
8407 if (!SCALAR_INT_MODE_P (mode
) || !SCALAR_INT_MODE_P (GET_MODE (x
)))
8408 return gen_lowpart_or_truncate (mode
, x
);
8413 /* If X is a (clobber (const_int)), return it since we know we are
8414 generating something that won't match. */
8421 x
= expand_compound_operation (x
);
8422 if (GET_CODE (x
) != code
)
8423 return force_to_mode (x
, mode
, mask
, next_select
);
8427 /* Similarly for a truncate. */
8428 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8431 /* If this is an AND with a constant, convert it into an AND
8432 whose constant is the AND of that constant with MASK. If it
8433 remains an AND of MASK, delete it since it is redundant. */
8435 if (CONST_INT_P (XEXP (x
, 1)))
8437 x
= simplify_and_const_int (x
, op_mode
, XEXP (x
, 0),
8438 mask
& INTVAL (XEXP (x
, 1)));
8440 /* If X is still an AND, see if it is an AND with a mask that
8441 is just some low-order bits. If so, and it is MASK, we don't
8444 if (GET_CODE (x
) == AND
&& CONST_INT_P (XEXP (x
, 1))
8445 && ((INTVAL (XEXP (x
, 1)) & GET_MODE_MASK (GET_MODE (x
)))
8449 /* If it remains an AND, try making another AND with the bits
8450 in the mode mask that aren't in MASK turned on. If the
8451 constant in the AND is wide enough, this might make a
8452 cheaper constant. */
8454 if (GET_CODE (x
) == AND
&& CONST_INT_P (XEXP (x
, 1))
8455 && GET_MODE_MASK (GET_MODE (x
)) != mask
8456 && HWI_COMPUTABLE_MODE_P (GET_MODE (x
)))
8458 unsigned HOST_WIDE_INT cval
8459 = UINTVAL (XEXP (x
, 1))
8460 | (GET_MODE_MASK (GET_MODE (x
)) & ~mask
);
8463 y
= simplify_gen_binary (AND
, GET_MODE (x
), XEXP (x
, 0),
8464 gen_int_mode (cval
, GET_MODE (x
)));
8465 if (set_src_cost (y
, GET_MODE (x
), optimize_this_for_speed_p
)
8466 < set_src_cost (x
, GET_MODE (x
), optimize_this_for_speed_p
))
8476 /* In (and (plus FOO C1) M), if M is a mask that just turns off
8477 low-order bits (as in an alignment operation) and FOO is already
8478 aligned to that boundary, mask C1 to that boundary as well.
8479 This may eliminate that PLUS and, later, the AND. */
8482 unsigned int width
= GET_MODE_PRECISION (mode
);
8483 unsigned HOST_WIDE_INT smask
= mask
;
8485 /* If MODE is narrower than HOST_WIDE_INT and mask is a negative
8486 number, sign extend it. */
8488 if (width
< HOST_BITS_PER_WIDE_INT
8489 && (smask
& (HOST_WIDE_INT_1U
<< (width
- 1))) != 0)
8490 smask
|= HOST_WIDE_INT_M1U
<< width
;
8492 if (CONST_INT_P (XEXP (x
, 1))
8493 && exact_log2 (- smask
) >= 0
8494 && (nonzero_bits (XEXP (x
, 0), mode
) & ~smask
) == 0
8495 && (INTVAL (XEXP (x
, 1)) & ~smask
) != 0)
8496 return force_to_mode (plus_constant (GET_MODE (x
), XEXP (x
, 0),
8497 (INTVAL (XEXP (x
, 1)) & smask
)),
8498 mode
, smask
, next_select
);
8501 /* ... fall through ... */
8504 /* Substituting into the operands of a widening MULT is not likely to
8505 create RTL matching a machine insn. */
8507 && (GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
8508 || GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
)
8509 && (GET_CODE (XEXP (x
, 1)) == ZERO_EXTEND
8510 || GET_CODE (XEXP (x
, 1)) == SIGN_EXTEND
)
8511 && REG_P (XEXP (XEXP (x
, 0), 0))
8512 && REG_P (XEXP (XEXP (x
, 1), 0)))
8513 return gen_lowpart_or_truncate (mode
, x
);
8515 /* For PLUS, MINUS and MULT, we need any bits less significant than the
8516 most significant bit in MASK since carries from those bits will
8517 affect the bits we are interested in. */
8522 /* If X is (minus C Y) where C's least set bit is larger than any bit
8523 in the mask, then we may replace with (neg Y). */
8524 if (CONST_INT_P (XEXP (x
, 0))
8525 && ((UINTVAL (XEXP (x
, 0)) & -UINTVAL (XEXP (x
, 0))) > mask
))
8527 x
= simplify_gen_unary (NEG
, GET_MODE (x
), XEXP (x
, 1),
8529 return force_to_mode (x
, mode
, mask
, next_select
);
8532 /* Similarly, if C contains every bit in the fuller_mask, then we may
8533 replace with (not Y). */
8534 if (CONST_INT_P (XEXP (x
, 0))
8535 && ((UINTVAL (XEXP (x
, 0)) | fuller_mask
) == UINTVAL (XEXP (x
, 0))))
8537 x
= simplify_gen_unary (NOT
, GET_MODE (x
),
8538 XEXP (x
, 1), GET_MODE (x
));
8539 return force_to_mode (x
, mode
, mask
, next_select
);
8547 /* If X is (ior (lshiftrt FOO C1) C2), try to commute the IOR and
8548 LSHIFTRT so we end up with an (and (lshiftrt (ior ...) ...) ...)
8549 operation which may be a bitfield extraction. Ensure that the
8550 constant we form is not wider than the mode of X. */
8552 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
8553 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
8554 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
8555 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
8556 && CONST_INT_P (XEXP (x
, 1))
8557 && ((INTVAL (XEXP (XEXP (x
, 0), 1))
8558 + floor_log2 (INTVAL (XEXP (x
, 1))))
8559 < GET_MODE_PRECISION (GET_MODE (x
)))
8560 && (UINTVAL (XEXP (x
, 1))
8561 & ~nonzero_bits (XEXP (x
, 0), GET_MODE (x
))) == 0)
8563 temp
= gen_int_mode ((INTVAL (XEXP (x
, 1)) & mask
)
8564 << INTVAL (XEXP (XEXP (x
, 0), 1)),
8566 temp
= simplify_gen_binary (GET_CODE (x
), GET_MODE (x
),
8567 XEXP (XEXP (x
, 0), 0), temp
);
8568 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
), temp
,
8569 XEXP (XEXP (x
, 0), 1));
8570 return force_to_mode (x
, mode
, mask
, next_select
);
8574 /* For most binary operations, just propagate into the operation and
8575 change the mode if we have an operation of that mode. */
8577 op0
= force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8578 op1
= force_to_mode (XEXP (x
, 1), mode
, mask
, next_select
);
8580 /* If we ended up truncating both operands, truncate the result of the
8581 operation instead. */
8582 if (GET_CODE (op0
) == TRUNCATE
8583 && GET_CODE (op1
) == TRUNCATE
)
8585 op0
= XEXP (op0
, 0);
8586 op1
= XEXP (op1
, 0);
8589 op0
= gen_lowpart_or_truncate (op_mode
, op0
);
8590 op1
= gen_lowpart_or_truncate (op_mode
, op1
);
8592 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
8593 x
= simplify_gen_binary (code
, op_mode
, op0
, op1
);
8597 /* For left shifts, do the same, but just for the first operand.
8598 However, we cannot do anything with shifts where we cannot
8599 guarantee that the counts are smaller than the size of the mode
8600 because such a count will have a different meaning in a
8603 if (! (CONST_INT_P (XEXP (x
, 1))
8604 && INTVAL (XEXP (x
, 1)) >= 0
8605 && INTVAL (XEXP (x
, 1)) < GET_MODE_PRECISION (mode
))
8606 && ! (GET_MODE (XEXP (x
, 1)) != VOIDmode
8607 && (nonzero_bits (XEXP (x
, 1), GET_MODE (XEXP (x
, 1)))
8608 < (unsigned HOST_WIDE_INT
) GET_MODE_PRECISION (mode
))))
8611 /* If the shift count is a constant and we can do arithmetic in
8612 the mode of the shift, refine which bits we need. Otherwise, use the
8613 conservative form of the mask. */
8614 if (CONST_INT_P (XEXP (x
, 1))
8615 && INTVAL (XEXP (x
, 1)) >= 0
8616 && INTVAL (XEXP (x
, 1)) < GET_MODE_PRECISION (op_mode
)
8617 && HWI_COMPUTABLE_MODE_P (op_mode
))
8618 mask
>>= INTVAL (XEXP (x
, 1));
8622 op0
= gen_lowpart_or_truncate (op_mode
,
8623 force_to_mode (XEXP (x
, 0), op_mode
,
8624 mask
, next_select
));
8626 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
8627 x
= simplify_gen_binary (code
, op_mode
, op0
, XEXP (x
, 1));
8631 /* Here we can only do something if the shift count is a constant,
8632 this shift constant is valid for the host, and we can do arithmetic
8635 if (CONST_INT_P (XEXP (x
, 1))
8636 && INTVAL (XEXP (x
, 1)) >= 0
8637 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
8638 && HWI_COMPUTABLE_MODE_P (op_mode
))
8640 rtx inner
= XEXP (x
, 0);
8641 unsigned HOST_WIDE_INT inner_mask
;
8643 /* Select the mask of the bits we need for the shift operand. */
8644 inner_mask
= mask
<< INTVAL (XEXP (x
, 1));
8646 /* We can only change the mode of the shift if we can do arithmetic
8647 in the mode of the shift and INNER_MASK is no wider than the
8648 width of X's mode. */
8649 if ((inner_mask
& ~GET_MODE_MASK (GET_MODE (x
))) != 0)
8650 op_mode
= GET_MODE (x
);
8652 inner
= force_to_mode (inner
, op_mode
, inner_mask
, next_select
);
8654 if (GET_MODE (x
) != op_mode
|| inner
!= XEXP (x
, 0))
8655 x
= simplify_gen_binary (LSHIFTRT
, op_mode
, inner
, XEXP (x
, 1));
8658 /* If we have (and (lshiftrt FOO C1) C2) where the combination of the
8659 shift and AND produces only copies of the sign bit (C2 is one less
8660 than a power of two), we can do this with just a shift. */
8662 if (GET_CODE (x
) == LSHIFTRT
8663 && CONST_INT_P (XEXP (x
, 1))
8664 /* The shift puts one of the sign bit copies in the least significant
8666 && ((INTVAL (XEXP (x
, 1))
8667 + num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0))))
8668 >= GET_MODE_PRECISION (GET_MODE (x
)))
8669 && exact_log2 (mask
+ 1) >= 0
8670 /* Number of bits left after the shift must be more than the mask
8672 && ((INTVAL (XEXP (x
, 1)) + exact_log2 (mask
+ 1))
8673 <= GET_MODE_PRECISION (GET_MODE (x
)))
8674 /* Must be more sign bit copies than the mask needs. */
8675 && ((int) num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
8676 >= exact_log2 (mask
+ 1)))
8677 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
8678 GEN_INT (GET_MODE_PRECISION (GET_MODE (x
))
8679 - exact_log2 (mask
+ 1)));
8684 /* If we are just looking for the sign bit, we don't need this shift at
8685 all, even if it has a variable count. */
8686 if (val_signbit_p (GET_MODE (x
), mask
))
8687 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8689 /* If this is a shift by a constant, get a mask that contains those bits
8690 that are not copies of the sign bit. We then have two cases: If
8691 MASK only includes those bits, this can be a logical shift, which may
8692 allow simplifications. If MASK is a single-bit field not within
8693 those bits, we are requesting a copy of the sign bit and hence can
8694 shift the sign bit to the appropriate location. */
8696 if (CONST_INT_P (XEXP (x
, 1)) && INTVAL (XEXP (x
, 1)) >= 0
8697 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
)
8701 /* If the considered data is wider than HOST_WIDE_INT, we can't
8702 represent a mask for all its bits in a single scalar.
8703 But we only care about the lower bits, so calculate these. */
8705 if (GET_MODE_PRECISION (GET_MODE (x
)) > HOST_BITS_PER_WIDE_INT
)
8707 nonzero
= ~(unsigned HOST_WIDE_INT
) 0;
8709 /* GET_MODE_PRECISION (GET_MODE (x)) - INTVAL (XEXP (x, 1))
8710 is the number of bits a full-width mask would have set.
8711 We need only shift if these are fewer than nonzero can
8712 hold. If not, we must keep all bits set in nonzero. */
8714 if (GET_MODE_PRECISION (GET_MODE (x
)) - INTVAL (XEXP (x
, 1))
8715 < HOST_BITS_PER_WIDE_INT
)
8716 nonzero
>>= INTVAL (XEXP (x
, 1))
8717 + HOST_BITS_PER_WIDE_INT
8718 - GET_MODE_PRECISION (GET_MODE (x
)) ;
8722 nonzero
= GET_MODE_MASK (GET_MODE (x
));
8723 nonzero
>>= INTVAL (XEXP (x
, 1));
8726 if ((mask
& ~nonzero
) == 0)
8728 x
= simplify_shift_const (NULL_RTX
, LSHIFTRT
, GET_MODE (x
),
8729 XEXP (x
, 0), INTVAL (XEXP (x
, 1)));
8730 if (GET_CODE (x
) != ASHIFTRT
)
8731 return force_to_mode (x
, mode
, mask
, next_select
);
8734 else if ((i
= exact_log2 (mask
)) >= 0)
8736 x
= simplify_shift_const
8737 (NULL_RTX
, LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
8738 GET_MODE_PRECISION (GET_MODE (x
)) - 1 - i
);
8740 if (GET_CODE (x
) != ASHIFTRT
)
8741 return force_to_mode (x
, mode
, mask
, next_select
);
8745 /* If MASK is 1, convert this to an LSHIFTRT. This can be done
8746 even if the shift count isn't a constant. */
8748 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
),
8749 XEXP (x
, 0), XEXP (x
, 1));
8753 /* If this is a zero- or sign-extension operation that just affects bits
8754 we don't care about, remove it. Be sure the call above returned
8755 something that is still a shift. */
8757 if ((GET_CODE (x
) == LSHIFTRT
|| GET_CODE (x
) == ASHIFTRT
)
8758 && CONST_INT_P (XEXP (x
, 1))
8759 && INTVAL (XEXP (x
, 1)) >= 0
8760 && (INTVAL (XEXP (x
, 1))
8761 <= GET_MODE_PRECISION (GET_MODE (x
)) - (floor_log2 (mask
) + 1))
8762 && GET_CODE (XEXP (x
, 0)) == ASHIFT
8763 && XEXP (XEXP (x
, 0), 1) == XEXP (x
, 1))
8764 return force_to_mode (XEXP (XEXP (x
, 0), 0), mode
, mask
,
8771 /* If the shift count is constant and we can do computations
8772 in the mode of X, compute where the bits we care about are.
8773 Otherwise, we can't do anything. Don't change the mode of
8774 the shift or propagate MODE into the shift, though. */
8775 if (CONST_INT_P (XEXP (x
, 1))
8776 && INTVAL (XEXP (x
, 1)) >= 0)
8778 temp
= simplify_binary_operation (code
== ROTATE
? ROTATERT
: ROTATE
,
8780 gen_int_mode (mask
, GET_MODE (x
)),
8782 if (temp
&& CONST_INT_P (temp
))
8783 x
= simplify_gen_binary (code
, GET_MODE (x
),
8784 force_to_mode (XEXP (x
, 0), GET_MODE (x
),
8785 INTVAL (temp
), next_select
),
8791 /* If we just want the low-order bit, the NEG isn't needed since it
8792 won't change the low-order bit. */
8794 return force_to_mode (XEXP (x
, 0), mode
, mask
, just_select
);
8796 /* We need any bits less significant than the most significant bit in
8797 MASK since carries from those bits will affect the bits we are
8803 /* (not FOO) is (xor FOO CONST), so if FOO is an LSHIFTRT, we can do the
8804 same as the XOR case above. Ensure that the constant we form is not
8805 wider than the mode of X. */
8807 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
8808 && CONST_INT_P (XEXP (XEXP (x
, 0), 1))
8809 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
8810 && (INTVAL (XEXP (XEXP (x
, 0), 1)) + floor_log2 (mask
)
8811 < GET_MODE_PRECISION (GET_MODE (x
)))
8812 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
8814 temp
= gen_int_mode (mask
<< INTVAL (XEXP (XEXP (x
, 0), 1)),
8816 temp
= simplify_gen_binary (XOR
, GET_MODE (x
),
8817 XEXP (XEXP (x
, 0), 0), temp
);
8818 x
= simplify_gen_binary (LSHIFTRT
, GET_MODE (x
),
8819 temp
, XEXP (XEXP (x
, 0), 1));
8821 return force_to_mode (x
, mode
, mask
, next_select
);
8824 /* (and (not FOO) CONST) is (not (or FOO (not CONST))), so we must
8825 use the full mask inside the NOT. */
8829 op0
= gen_lowpart_or_truncate (op_mode
,
8830 force_to_mode (XEXP (x
, 0), mode
, mask
,
8832 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
8833 x
= simplify_gen_unary (code
, op_mode
, op0
, op_mode
);
8837 /* (and (ne FOO 0) CONST) can be (and FOO CONST) if CONST is included
8838 in STORE_FLAG_VALUE and FOO has a single bit that might be nonzero,
8839 which is equal to STORE_FLAG_VALUE. */
8840 if ((mask
& ~STORE_FLAG_VALUE
) == 0
8841 && XEXP (x
, 1) == const0_rtx
8842 && GET_MODE (XEXP (x
, 0)) == mode
8843 && exact_log2 (nonzero_bits (XEXP (x
, 0), mode
)) >= 0
8844 && (nonzero_bits (XEXP (x
, 0), mode
)
8845 == (unsigned HOST_WIDE_INT
) STORE_FLAG_VALUE
))
8846 return force_to_mode (XEXP (x
, 0), mode
, mask
, next_select
);
8851 /* We have no way of knowing if the IF_THEN_ELSE can itself be
8852 written in a narrower mode. We play it safe and do not do so. */
8854 op0
= gen_lowpart_or_truncate (GET_MODE (x
),
8855 force_to_mode (XEXP (x
, 1), mode
,
8856 mask
, next_select
));
8857 op1
= gen_lowpart_or_truncate (GET_MODE (x
),
8858 force_to_mode (XEXP (x
, 2), mode
,
8859 mask
, next_select
));
8860 if (op0
!= XEXP (x
, 1) || op1
!= XEXP (x
, 2))
8861 x
= simplify_gen_ternary (IF_THEN_ELSE
, GET_MODE (x
),
8862 GET_MODE (XEXP (x
, 0)), XEXP (x
, 0),
8870 /* Ensure we return a value of the proper mode. */
8871 return gen_lowpart_or_truncate (mode
, x
);
8874 /* Return nonzero if X is an expression that has one of two values depending on
8875 whether some other value is zero or nonzero. In that case, we return the
8876 value that is being tested, *PTRUE is set to the value if the rtx being
8877 returned has a nonzero value, and *PFALSE is set to the other alternative.
8879 If we return zero, we set *PTRUE and *PFALSE to X. */
8882 if_then_else_cond (rtx x
, rtx
*ptrue
, rtx
*pfalse
)
8884 machine_mode mode
= GET_MODE (x
);
8885 enum rtx_code code
= GET_CODE (x
);
8886 rtx cond0
, cond1
, true0
, true1
, false0
, false1
;
8887 unsigned HOST_WIDE_INT nz
;
8889 /* If we are comparing a value against zero, we are done. */
8890 if ((code
== NE
|| code
== EQ
)
8891 && XEXP (x
, 1) == const0_rtx
)
8893 *ptrue
= (code
== NE
) ? const_true_rtx
: const0_rtx
;
8894 *pfalse
= (code
== NE
) ? const0_rtx
: const_true_rtx
;
8898 /* If this is a unary operation whose operand has one of two values, apply
8899 our opcode to compute those values. */
8900 else if (UNARY_P (x
)
8901 && (cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
)) != 0)
8903 *ptrue
= simplify_gen_unary (code
, mode
, true0
, GET_MODE (XEXP (x
, 0)));
8904 *pfalse
= simplify_gen_unary (code
, mode
, false0
,
8905 GET_MODE (XEXP (x
, 0)));
8909 /* If this is a COMPARE, do nothing, since the IF_THEN_ELSE we would
8910 make can't possibly match and would suppress other optimizations. */
8911 else if (code
== COMPARE
)
8914 /* If this is a binary operation, see if either side has only one of two
8915 values. If either one does or if both do and they are conditional on
8916 the same value, compute the new true and false values. */
8917 else if (BINARY_P (x
))
8919 cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
);
8920 cond1
= if_then_else_cond (XEXP (x
, 1), &true1
, &false1
);
8922 if ((cond0
!= 0 || cond1
!= 0)
8923 && ! (cond0
!= 0 && cond1
!= 0 && ! rtx_equal_p (cond0
, cond1
)))
8925 /* If if_then_else_cond returned zero, then true/false are the
8926 same rtl. We must copy one of them to prevent invalid rtl
8929 true0
= copy_rtx (true0
);
8930 else if (cond1
== 0)
8931 true1
= copy_rtx (true1
);
8933 if (COMPARISON_P (x
))
8935 *ptrue
= simplify_gen_relational (code
, mode
, VOIDmode
,
8937 *pfalse
= simplify_gen_relational (code
, mode
, VOIDmode
,
8942 *ptrue
= simplify_gen_binary (code
, mode
, true0
, true1
);
8943 *pfalse
= simplify_gen_binary (code
, mode
, false0
, false1
);
8946 return cond0
? cond0
: cond1
;
8949 /* See if we have PLUS, IOR, XOR, MINUS or UMAX, where one of the
8950 operands is zero when the other is nonzero, and vice-versa,
8951 and STORE_FLAG_VALUE is 1 or -1. */
8953 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
8954 && (code
== PLUS
|| code
== IOR
|| code
== XOR
|| code
== MINUS
8956 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
8958 rtx op0
= XEXP (XEXP (x
, 0), 1);
8959 rtx op1
= XEXP (XEXP (x
, 1), 1);
8961 cond0
= XEXP (XEXP (x
, 0), 0);
8962 cond1
= XEXP (XEXP (x
, 1), 0);
8964 if (COMPARISON_P (cond0
)
8965 && COMPARISON_P (cond1
)
8966 && ((GET_CODE (cond0
) == reversed_comparison_code (cond1
, NULL
)
8967 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
8968 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
8969 || ((swap_condition (GET_CODE (cond0
))
8970 == reversed_comparison_code (cond1
, NULL
))
8971 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
8972 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
8973 && ! side_effects_p (x
))
8975 *ptrue
= simplify_gen_binary (MULT
, mode
, op0
, const_true_rtx
);
8976 *pfalse
= simplify_gen_binary (MULT
, mode
,
8978 ? simplify_gen_unary (NEG
, mode
,
8986 /* Similarly for MULT, AND and UMIN, except that for these the result
8988 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
8989 && (code
== MULT
|| code
== AND
|| code
== UMIN
)
8990 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
8992 cond0
= XEXP (XEXP (x
, 0), 0);
8993 cond1
= XEXP (XEXP (x
, 1), 0);
8995 if (COMPARISON_P (cond0
)
8996 && COMPARISON_P (cond1
)
8997 && ((GET_CODE (cond0
) == reversed_comparison_code (cond1
, NULL
)
8998 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
8999 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
9000 || ((swap_condition (GET_CODE (cond0
))
9001 == reversed_comparison_code (cond1
, NULL
))
9002 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
9003 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
9004 && ! side_effects_p (x
))
9006 *ptrue
= *pfalse
= const0_rtx
;
9012 else if (code
== IF_THEN_ELSE
)
9014 /* If we have IF_THEN_ELSE already, extract the condition and
9015 canonicalize it if it is NE or EQ. */
9016 cond0
= XEXP (x
, 0);
9017 *ptrue
= XEXP (x
, 1), *pfalse
= XEXP (x
, 2);
9018 if (GET_CODE (cond0
) == NE
&& XEXP (cond0
, 1) == const0_rtx
)
9019 return XEXP (cond0
, 0);
9020 else if (GET_CODE (cond0
) == EQ
&& XEXP (cond0
, 1) == const0_rtx
)
9022 *ptrue
= XEXP (x
, 2), *pfalse
= XEXP (x
, 1);
9023 return XEXP (cond0
, 0);
9029 /* If X is a SUBREG, we can narrow both the true and false values
9030 if the inner expression, if there is a condition. */
9031 else if (code
== SUBREG
9032 && 0 != (cond0
= if_then_else_cond (SUBREG_REG (x
),
9035 true0
= simplify_gen_subreg (mode
, true0
,
9036 GET_MODE (SUBREG_REG (x
)), SUBREG_BYTE (x
));
9037 false0
= simplify_gen_subreg (mode
, false0
,
9038 GET_MODE (SUBREG_REG (x
)), SUBREG_BYTE (x
));
9039 if (true0
&& false0
)
9047 /* If X is a constant, this isn't special and will cause confusions
9048 if we treat it as such. Likewise if it is equivalent to a constant. */
9049 else if (CONSTANT_P (x
)
9050 || ((cond0
= get_last_value (x
)) != 0 && CONSTANT_P (cond0
)))
9053 /* If we're in BImode, canonicalize on 0 and STORE_FLAG_VALUE, as that
9054 will be least confusing to the rest of the compiler. */
9055 else if (mode
== BImode
)
9057 *ptrue
= GEN_INT (STORE_FLAG_VALUE
), *pfalse
= const0_rtx
;
9061 /* If X is known to be either 0 or -1, those are the true and
9062 false values when testing X. */
9063 else if (x
== constm1_rtx
|| x
== const0_rtx
9064 || (mode
!= VOIDmode
9065 && num_sign_bit_copies (x
, mode
) == GET_MODE_PRECISION (mode
)))
9067 *ptrue
= constm1_rtx
, *pfalse
= const0_rtx
;
9071 /* Likewise for 0 or a single bit. */
9072 else if (HWI_COMPUTABLE_MODE_P (mode
)
9073 && exact_log2 (nz
= nonzero_bits (x
, mode
)) >= 0)
9075 *ptrue
= gen_int_mode (nz
, mode
), *pfalse
= const0_rtx
;
9079 /* Otherwise fail; show no condition with true and false values the same. */
9080 *ptrue
= *pfalse
= x
;
9084 /* Return the value of expression X given the fact that condition COND
9085 is known to be true when applied to REG as its first operand and VAL
9086 as its second. X is known to not be shared and so can be modified in
9089 We only handle the simplest cases, and specifically those cases that
9090 arise with IF_THEN_ELSE expressions. */
9093 known_cond (rtx x
, enum rtx_code cond
, rtx reg
, rtx val
)
9095 enum rtx_code code
= GET_CODE (x
);
9099 if (side_effects_p (x
))
9102 /* If either operand of the condition is a floating point value,
9103 then we have to avoid collapsing an EQ comparison. */
9105 && rtx_equal_p (x
, reg
)
9106 && ! FLOAT_MODE_P (GET_MODE (x
))
9107 && ! FLOAT_MODE_P (GET_MODE (val
)))
9110 if (cond
== UNEQ
&& rtx_equal_p (x
, reg
))
9113 /* If X is (abs REG) and we know something about REG's relationship
9114 with zero, we may be able to simplify this. */
9116 if (code
== ABS
&& rtx_equal_p (XEXP (x
, 0), reg
) && val
== const0_rtx
)
9119 case GE
: case GT
: case EQ
:
9122 return simplify_gen_unary (NEG
, GET_MODE (XEXP (x
, 0)),
9124 GET_MODE (XEXP (x
, 0)));
9129 /* The only other cases we handle are MIN, MAX, and comparisons if the
9130 operands are the same as REG and VAL. */
9132 else if (COMPARISON_P (x
) || COMMUTATIVE_ARITH_P (x
))
9134 if (rtx_equal_p (XEXP (x
, 0), val
))
9136 std::swap (val
, reg
);
9137 cond
= swap_condition (cond
);
9140 if (rtx_equal_p (XEXP (x
, 0), reg
) && rtx_equal_p (XEXP (x
, 1), val
))
9142 if (COMPARISON_P (x
))
9144 if (comparison_dominates_p (cond
, code
))
9145 return const_true_rtx
;
9147 code
= reversed_comparison_code (x
, NULL
);
9149 && comparison_dominates_p (cond
, code
))
9154 else if (code
== SMAX
|| code
== SMIN
9155 || code
== UMIN
|| code
== UMAX
)
9157 int unsignedp
= (code
== UMIN
|| code
== UMAX
);
9159 /* Do not reverse the condition when it is NE or EQ.
9160 This is because we cannot conclude anything about
9161 the value of 'SMAX (x, y)' when x is not equal to y,
9162 but we can when x equals y. */
9163 if ((code
== SMAX
|| code
== UMAX
)
9164 && ! (cond
== EQ
|| cond
== NE
))
9165 cond
= reverse_condition (cond
);
9170 return unsignedp
? x
: XEXP (x
, 1);
9172 return unsignedp
? x
: XEXP (x
, 0);
9174 return unsignedp
? XEXP (x
, 1) : x
;
9176 return unsignedp
? XEXP (x
, 0) : x
;
9183 else if (code
== SUBREG
)
9185 machine_mode inner_mode
= GET_MODE (SUBREG_REG (x
));
9186 rtx new_rtx
, r
= known_cond (SUBREG_REG (x
), cond
, reg
, val
);
9188 if (SUBREG_REG (x
) != r
)
9190 /* We must simplify subreg here, before we lose track of the
9191 original inner_mode. */
9192 new_rtx
= simplify_subreg (GET_MODE (x
), r
,
9193 inner_mode
, SUBREG_BYTE (x
));
9197 SUBST (SUBREG_REG (x
), r
);
9202 /* We don't have to handle SIGN_EXTEND here, because even in the
9203 case of replacing something with a modeless CONST_INT, a
9204 CONST_INT is already (supposed to be) a valid sign extension for
9205 its narrower mode, which implies it's already properly
9206 sign-extended for the wider mode. Now, for ZERO_EXTEND, the
9207 story is different. */
9208 else if (code
== ZERO_EXTEND
)
9210 machine_mode inner_mode
= GET_MODE (XEXP (x
, 0));
9211 rtx new_rtx
, r
= known_cond (XEXP (x
, 0), cond
, reg
, val
);
9213 if (XEXP (x
, 0) != r
)
9215 /* We must simplify the zero_extend here, before we lose
9216 track of the original inner_mode. */
9217 new_rtx
= simplify_unary_operation (ZERO_EXTEND
, GET_MODE (x
),
9222 SUBST (XEXP (x
, 0), r
);
9228 fmt
= GET_RTX_FORMAT (code
);
9229 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
9232 SUBST (XEXP (x
, i
), known_cond (XEXP (x
, i
), cond
, reg
, val
));
9233 else if (fmt
[i
] == 'E')
9234 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
9235 SUBST (XVECEXP (x
, i
, j
), known_cond (XVECEXP (x
, i
, j
),
9242 /* See if X and Y are equal for the purposes of seeing if we can rewrite an
9243 assignment as a field assignment. */
9246 rtx_equal_for_field_assignment_p (rtx x
, rtx y
, bool widen_x
)
9248 if (widen_x
&& GET_MODE (x
) != GET_MODE (y
))
9250 if (GET_MODE_SIZE (GET_MODE (x
)) > GET_MODE_SIZE (GET_MODE (y
)))
9252 if (BYTES_BIG_ENDIAN
!= WORDS_BIG_ENDIAN
)
9254 /* For big endian, adjust the memory offset. */
9255 if (BYTES_BIG_ENDIAN
)
9256 x
= adjust_address_nv (x
, GET_MODE (y
),
9257 -subreg_lowpart_offset (GET_MODE (x
),
9260 x
= adjust_address_nv (x
, GET_MODE (y
), 0);
9263 if (x
== y
|| rtx_equal_p (x
, y
))
9266 if (x
== 0 || y
== 0 || GET_MODE (x
) != GET_MODE (y
))
9269 /* Check for a paradoxical SUBREG of a MEM compared with the MEM.
9270 Note that all SUBREGs of MEM are paradoxical; otherwise they
9271 would have been rewritten. */
9272 if (MEM_P (x
) && GET_CODE (y
) == SUBREG
9273 && MEM_P (SUBREG_REG (y
))
9274 && rtx_equal_p (SUBREG_REG (y
),
9275 gen_lowpart (GET_MODE (SUBREG_REG (y
)), x
)))
9278 if (MEM_P (y
) && GET_CODE (x
) == SUBREG
9279 && MEM_P (SUBREG_REG (x
))
9280 && rtx_equal_p (SUBREG_REG (x
),
9281 gen_lowpart (GET_MODE (SUBREG_REG (x
)), y
)))
9284 /* We used to see if get_last_value of X and Y were the same but that's
9285 not correct. In one direction, we'll cause the assignment to have
9286 the wrong destination and in the case, we'll import a register into this
9287 insn that might have already have been dead. So fail if none of the
9288 above cases are true. */
9292 /* See if X, a SET operation, can be rewritten as a bit-field assignment.
9293 Return that assignment if so.
9295 We only handle the most common cases. */
9298 make_field_assignment (rtx x
)
9300 rtx dest
= SET_DEST (x
);
9301 rtx src
= SET_SRC (x
);
9306 unsigned HOST_WIDE_INT len
;
9310 /* If SRC was (and (not (ashift (const_int 1) POS)) DEST), this is
9311 a clear of a one-bit field. We will have changed it to
9312 (and (rotate (const_int -2) POS) DEST), so check for that. Also check
9315 if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == ROTATE
9316 && CONST_INT_P (XEXP (XEXP (src
, 0), 0))
9317 && INTVAL (XEXP (XEXP (src
, 0), 0)) == -2
9318 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9320 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
9323 return gen_rtx_SET (assign
, const0_rtx
);
9327 if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == SUBREG
9328 && subreg_lowpart_p (XEXP (src
, 0))
9329 && (GET_MODE_SIZE (GET_MODE (XEXP (src
, 0)))
9330 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (src
, 0)))))
9331 && GET_CODE (SUBREG_REG (XEXP (src
, 0))) == ROTATE
9332 && CONST_INT_P (XEXP (SUBREG_REG (XEXP (src
, 0)), 0))
9333 && INTVAL (XEXP (SUBREG_REG (XEXP (src
, 0)), 0)) == -2
9334 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9336 assign
= make_extraction (VOIDmode
, dest
, 0,
9337 XEXP (SUBREG_REG (XEXP (src
, 0)), 1),
9340 return gen_rtx_SET (assign
, const0_rtx
);
9344 /* If SRC is (ior (ashift (const_int 1) POS) DEST), this is a set of a
9346 if (GET_CODE (src
) == IOR
&& GET_CODE (XEXP (src
, 0)) == ASHIFT
9347 && XEXP (XEXP (src
, 0), 0) == const1_rtx
9348 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
9350 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
9353 return gen_rtx_SET (assign
, const1_rtx
);
9357 /* If DEST is already a field assignment, i.e. ZERO_EXTRACT, and the
9358 SRC is an AND with all bits of that field set, then we can discard
9360 if (GET_CODE (dest
) == ZERO_EXTRACT
9361 && CONST_INT_P (XEXP (dest
, 1))
9362 && GET_CODE (src
) == AND
9363 && CONST_INT_P (XEXP (src
, 1)))
9365 HOST_WIDE_INT width
= INTVAL (XEXP (dest
, 1));
9366 unsigned HOST_WIDE_INT and_mask
= INTVAL (XEXP (src
, 1));
9367 unsigned HOST_WIDE_INT ze_mask
;
9369 if (width
>= HOST_BITS_PER_WIDE_INT
)
9372 ze_mask
= ((unsigned HOST_WIDE_INT
)1 << width
) - 1;
9374 /* Complete overlap. We can remove the source AND. */
9375 if ((and_mask
& ze_mask
) == ze_mask
)
9376 return gen_rtx_SET (dest
, XEXP (src
, 0));
9378 /* Partial overlap. We can reduce the source AND. */
9379 if ((and_mask
& ze_mask
) != and_mask
)
9381 mode
= GET_MODE (src
);
9382 src
= gen_rtx_AND (mode
, XEXP (src
, 0),
9383 gen_int_mode (and_mask
& ze_mask
, mode
));
9384 return gen_rtx_SET (dest
, src
);
9388 /* The other case we handle is assignments into a constant-position
9389 field. They look like (ior/xor (and DEST C1) OTHER). If C1 represents
9390 a mask that has all one bits except for a group of zero bits and
9391 OTHER is known to have zeros where C1 has ones, this is such an
9392 assignment. Compute the position and length from C1. Shift OTHER
9393 to the appropriate position, force it to the required mode, and
9394 make the extraction. Check for the AND in both operands. */
9396 /* One or more SUBREGs might obscure the constant-position field
9397 assignment. The first one we are likely to encounter is an outer
9398 narrowing SUBREG, which we can just strip for the purposes of
9399 identifying the constant-field assignment. */
9400 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
))
9401 src
= SUBREG_REG (src
);
9403 if (GET_CODE (src
) != IOR
&& GET_CODE (src
) != XOR
)
9406 rhs
= expand_compound_operation (XEXP (src
, 0));
9407 lhs
= expand_compound_operation (XEXP (src
, 1));
9409 if (GET_CODE (rhs
) == AND
9410 && CONST_INT_P (XEXP (rhs
, 1))
9411 && rtx_equal_for_field_assignment_p (XEXP (rhs
, 0), dest
))
9412 c1
= INTVAL (XEXP (rhs
, 1)), other
= lhs
;
9413 /* The second SUBREG that might get in the way is a paradoxical
9414 SUBREG around the first operand of the AND. We want to
9415 pretend the operand is as wide as the destination here. We
9416 do this by adjusting the MEM to wider mode for the sole
9417 purpose of the call to rtx_equal_for_field_assignment_p. Also
9418 note this trick only works for MEMs. */
9419 else if (GET_CODE (rhs
) == AND
9420 && paradoxical_subreg_p (XEXP (rhs
, 0))
9421 && MEM_P (SUBREG_REG (XEXP (rhs
, 0)))
9422 && CONST_INT_P (XEXP (rhs
, 1))
9423 && rtx_equal_for_field_assignment_p (SUBREG_REG (XEXP (rhs
, 0)),
9425 c1
= INTVAL (XEXP (rhs
, 1)), other
= lhs
;
9426 else if (GET_CODE (lhs
) == AND
9427 && CONST_INT_P (XEXP (lhs
, 1))
9428 && rtx_equal_for_field_assignment_p (XEXP (lhs
, 0), dest
))
9429 c1
= INTVAL (XEXP (lhs
, 1)), other
= rhs
;
9430 /* The second SUBREG that might get in the way is a paradoxical
9431 SUBREG around the first operand of the AND. We want to
9432 pretend the operand is as wide as the destination here. We
9433 do this by adjusting the MEM to wider mode for the sole
9434 purpose of the call to rtx_equal_for_field_assignment_p. Also
9435 note this trick only works for MEMs. */
9436 else if (GET_CODE (lhs
) == AND
9437 && paradoxical_subreg_p (XEXP (lhs
, 0))
9438 && MEM_P (SUBREG_REG (XEXP (lhs
, 0)))
9439 && CONST_INT_P (XEXP (lhs
, 1))
9440 && rtx_equal_for_field_assignment_p (SUBREG_REG (XEXP (lhs
, 0)),
9442 c1
= INTVAL (XEXP (lhs
, 1)), other
= rhs
;
9446 pos
= get_pos_from_mask ((~c1
) & GET_MODE_MASK (GET_MODE (dest
)), &len
);
9447 if (pos
< 0 || pos
+ len
> GET_MODE_PRECISION (GET_MODE (dest
))
9448 || GET_MODE_PRECISION (GET_MODE (dest
)) > HOST_BITS_PER_WIDE_INT
9449 || (c1
& nonzero_bits (other
, GET_MODE (dest
))) != 0)
9452 assign
= make_extraction (VOIDmode
, dest
, pos
, NULL_RTX
, len
, 1, 1, 0);
9456 /* The mode to use for the source is the mode of the assignment, or of
9457 what is inside a possible STRICT_LOW_PART. */
9458 mode
= (GET_CODE (assign
) == STRICT_LOW_PART
9459 ? GET_MODE (XEXP (assign
, 0)) : GET_MODE (assign
));
9461 /* Shift OTHER right POS places and make it the source, restricting it
9462 to the proper length and mode. */
9464 src
= canon_reg_for_combine (simplify_shift_const (NULL_RTX
, LSHIFTRT
,
9468 src
= force_to_mode (src
, mode
,
9469 GET_MODE_PRECISION (mode
) >= HOST_BITS_PER_WIDE_INT
9470 ? ~(unsigned HOST_WIDE_INT
) 0
9471 : ((unsigned HOST_WIDE_INT
) 1 << len
) - 1,
9474 /* If SRC is masked by an AND that does not make a difference in
9475 the value being stored, strip it. */
9476 if (GET_CODE (assign
) == ZERO_EXTRACT
9477 && CONST_INT_P (XEXP (assign
, 1))
9478 && INTVAL (XEXP (assign
, 1)) < HOST_BITS_PER_WIDE_INT
9479 && GET_CODE (src
) == AND
9480 && CONST_INT_P (XEXP (src
, 1))
9481 && UINTVAL (XEXP (src
, 1))
9482 == ((unsigned HOST_WIDE_INT
) 1 << INTVAL (XEXP (assign
, 1))) - 1)
9483 src
= XEXP (src
, 0);
9485 return gen_rtx_SET (assign
, src
);
9488 /* See if X is of the form (+ (* a c) (* b c)) and convert to (* (+ a b) c)
9492 apply_distributive_law (rtx x
)
9494 enum rtx_code code
= GET_CODE (x
);
9495 enum rtx_code inner_code
;
9496 rtx lhs
, rhs
, other
;
9499 /* Distributivity is not true for floating point as it can change the
9500 value. So we don't do it unless -funsafe-math-optimizations. */
9501 if (FLOAT_MODE_P (GET_MODE (x
))
9502 && ! flag_unsafe_math_optimizations
)
9505 /* The outer operation can only be one of the following: */
9506 if (code
!= IOR
&& code
!= AND
&& code
!= XOR
9507 && code
!= PLUS
&& code
!= MINUS
)
9513 /* If either operand is a primitive we can't do anything, so get out
9515 if (OBJECT_P (lhs
) || OBJECT_P (rhs
))
9518 lhs
= expand_compound_operation (lhs
);
9519 rhs
= expand_compound_operation (rhs
);
9520 inner_code
= GET_CODE (lhs
);
9521 if (inner_code
!= GET_CODE (rhs
))
9524 /* See if the inner and outer operations distribute. */
9531 /* These all distribute except over PLUS. */
9532 if (code
== PLUS
|| code
== MINUS
)
9537 if (code
!= PLUS
&& code
!= MINUS
)
9542 /* This is also a multiply, so it distributes over everything. */
9545 /* This used to handle SUBREG, but this turned out to be counter-
9546 productive, since (subreg (op ...)) usually is not handled by
9547 insn patterns, and this "optimization" therefore transformed
9548 recognizable patterns into unrecognizable ones. Therefore the
9549 SUBREG case was removed from here.
9551 It is possible that distributing SUBREG over arithmetic operations
9552 leads to an intermediate result than can then be optimized further,
9553 e.g. by moving the outer SUBREG to the other side of a SET as done
9554 in simplify_set. This seems to have been the original intent of
9555 handling SUBREGs here.
9557 However, with current GCC this does not appear to actually happen,
9558 at least on major platforms. If some case is found where removing
9559 the SUBREG case here prevents follow-on optimizations, distributing
9560 SUBREGs ought to be re-added at that place, e.g. in simplify_set. */
9566 /* Set LHS and RHS to the inner operands (A and B in the example
9567 above) and set OTHER to the common operand (C in the example).
9568 There is only one way to do this unless the inner operation is
9570 if (COMMUTATIVE_ARITH_P (lhs
)
9571 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 0)))
9572 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 1);
9573 else if (COMMUTATIVE_ARITH_P (lhs
)
9574 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 1)))
9575 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 0);
9576 else if (COMMUTATIVE_ARITH_P (lhs
)
9577 && rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 0)))
9578 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 1);
9579 else if (rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 1)))
9580 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 0);
9584 /* Form the new inner operation, seeing if it simplifies first. */
9585 tem
= simplify_gen_binary (code
, GET_MODE (x
), lhs
, rhs
);
9587 /* There is one exception to the general way of distributing:
9588 (a | c) ^ (b | c) -> (a ^ b) & ~c */
9589 if (code
== XOR
&& inner_code
== IOR
)
9592 other
= simplify_gen_unary (NOT
, GET_MODE (x
), other
, GET_MODE (x
));
9595 /* We may be able to continuing distributing the result, so call
9596 ourselves recursively on the inner operation before forming the
9597 outer operation, which we return. */
9598 return simplify_gen_binary (inner_code
, GET_MODE (x
),
9599 apply_distributive_law (tem
), other
);
9602 /* See if X is of the form (* (+ A B) C), and if so convert to
9603 (+ (* A C) (* B C)) and try to simplify.
9605 Most of the time, this results in no change. However, if some of
9606 the operands are the same or inverses of each other, simplifications
9609 For example, (and (ior A B) (not B)) can occur as the result of
9610 expanding a bit field assignment. When we apply the distributive
9611 law to this, we get (ior (and (A (not B))) (and (B (not B)))),
9612 which then simplifies to (and (A (not B))).
9614 Note that no checks happen on the validity of applying the inverse
9615 distributive law. This is pointless since we can do it in the
9616 few places where this routine is called.
9618 N is the index of the term that is decomposed (the arithmetic operation,
9619 i.e. (+ A B) in the first example above). !N is the index of the term that
9620 is distributed, i.e. of C in the first example above. */
9622 distribute_and_simplify_rtx (rtx x
, int n
)
9625 enum rtx_code outer_code
, inner_code
;
9626 rtx decomposed
, distributed
, inner_op0
, inner_op1
, new_op0
, new_op1
, tmp
;
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 decomposed
= XEXP (x
, n
);
9635 if (!ARITHMETIC_P (decomposed
))
9638 mode
= GET_MODE (x
);
9639 outer_code
= GET_CODE (x
);
9640 distributed
= XEXP (x
, !n
);
9642 inner_code
= GET_CODE (decomposed
);
9643 inner_op0
= XEXP (decomposed
, 0);
9644 inner_op1
= XEXP (decomposed
, 1);
9646 /* Special case (and (xor B C) (not A)), which is equivalent to
9647 (xor (ior A B) (ior A C)) */
9648 if (outer_code
== AND
&& inner_code
== XOR
&& GET_CODE (distributed
) == NOT
)
9650 distributed
= XEXP (distributed
, 0);
9656 /* Distribute the second term. */
9657 new_op0
= simplify_gen_binary (outer_code
, mode
, inner_op0
, distributed
);
9658 new_op1
= simplify_gen_binary (outer_code
, mode
, inner_op1
, distributed
);
9662 /* Distribute the first term. */
9663 new_op0
= simplify_gen_binary (outer_code
, mode
, distributed
, inner_op0
);
9664 new_op1
= simplify_gen_binary (outer_code
, mode
, distributed
, inner_op1
);
9667 tmp
= apply_distributive_law (simplify_gen_binary (inner_code
, mode
,
9669 if (GET_CODE (tmp
) != outer_code
9670 && (set_src_cost (tmp
, mode
, optimize_this_for_speed_p
)
9671 < set_src_cost (x
, mode
, optimize_this_for_speed_p
)))
9677 /* Simplify a logical `and' of VAROP with the constant CONSTOP, to be done
9678 in MODE. Return an equivalent form, if different from (and VAROP
9679 (const_int CONSTOP)). Otherwise, return NULL_RTX. */
9682 simplify_and_const_int_1 (machine_mode mode
, rtx varop
,
9683 unsigned HOST_WIDE_INT constop
)
9685 unsigned HOST_WIDE_INT nonzero
;
9686 unsigned HOST_WIDE_INT orig_constop
;
9691 orig_constop
= constop
;
9692 if (GET_CODE (varop
) == CLOBBER
)
9695 /* Simplify VAROP knowing that we will be only looking at some of the
9698 Note by passing in CONSTOP, we guarantee that the bits not set in
9699 CONSTOP are not significant and will never be examined. We must
9700 ensure that is the case by explicitly masking out those bits
9701 before returning. */
9702 varop
= force_to_mode (varop
, mode
, constop
, 0);
9704 /* If VAROP is a CLOBBER, we will fail so return it. */
9705 if (GET_CODE (varop
) == CLOBBER
)
9708 /* If VAROP is a CONST_INT, then we need to apply the mask in CONSTOP
9709 to VAROP and return the new constant. */
9710 if (CONST_INT_P (varop
))
9711 return gen_int_mode (INTVAL (varop
) & constop
, mode
);
9713 /* See what bits may be nonzero in VAROP. Unlike the general case of
9714 a call to nonzero_bits, here we don't care about bits outside
9717 nonzero
= nonzero_bits (varop
, mode
) & GET_MODE_MASK (mode
);
9719 /* Turn off all bits in the constant that are known to already be zero.
9720 Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS
9721 which is tested below. */
9725 /* If we don't have any bits left, return zero. */
9729 /* If VAROP is a NEG of something known to be zero or 1 and CONSTOP is
9730 a power of two, we can replace this with an ASHIFT. */
9731 if (GET_CODE (varop
) == NEG
&& nonzero_bits (XEXP (varop
, 0), mode
) == 1
9732 && (i
= exact_log2 (constop
)) >= 0)
9733 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (varop
, 0), i
);
9735 /* If VAROP is an IOR or XOR, apply the AND to both branches of the IOR
9736 or XOR, then try to apply the distributive law. This may eliminate
9737 operations if either branch can be simplified because of the AND.
9738 It may also make some cases more complex, but those cases probably
9739 won't match a pattern either with or without this. */
9741 if (GET_CODE (varop
) == IOR
|| GET_CODE (varop
) == XOR
)
9745 apply_distributive_law
9746 (simplify_gen_binary (GET_CODE (varop
), GET_MODE (varop
),
9747 simplify_and_const_int (NULL_RTX
,
9751 simplify_and_const_int (NULL_RTX
,
9756 /* If VAROP is PLUS, and the constant is a mask of low bits, distribute
9757 the AND and see if one of the operands simplifies to zero. If so, we
9758 may eliminate it. */
9760 if (GET_CODE (varop
) == PLUS
9761 && exact_log2 (constop
+ 1) >= 0)
9765 o0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (varop
, 0), constop
);
9766 o1
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (varop
, 1), constop
);
9767 if (o0
== const0_rtx
)
9769 if (o1
== const0_rtx
)
9773 /* Make a SUBREG if necessary. If we can't make it, fail. */
9774 varop
= gen_lowpart (mode
, varop
);
9775 if (varop
== NULL_RTX
|| GET_CODE (varop
) == CLOBBER
)
9778 /* If we are only masking insignificant bits, return VAROP. */
9779 if (constop
== nonzero
)
9782 if (varop
== orig_varop
&& constop
== orig_constop
)
9785 /* Otherwise, return an AND. */
9786 return simplify_gen_binary (AND
, mode
, varop
, gen_int_mode (constop
, mode
));
9790 /* We have X, a logical `and' of VAROP with the constant CONSTOP, to be done
9793 Return an equivalent form, if different from X. Otherwise, return X. If
9794 X is zero, we are to always construct the equivalent form. */
9797 simplify_and_const_int (rtx x
, machine_mode mode
, rtx varop
,
9798 unsigned HOST_WIDE_INT constop
)
9800 rtx tem
= simplify_and_const_int_1 (mode
, varop
, constop
);
9805 x
= simplify_gen_binary (AND
, GET_MODE (varop
), varop
,
9806 gen_int_mode (constop
, mode
));
9807 if (GET_MODE (x
) != mode
)
9808 x
= gen_lowpart (mode
, x
);
9812 /* Given a REG, X, compute which bits in X can be nonzero.
9813 We don't care about bits outside of those defined in MODE.
9815 For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
9816 a shift, AND, or zero_extract, we can do better. */
9819 reg_nonzero_bits_for_combine (const_rtx x
, machine_mode mode
,
9820 const_rtx known_x ATTRIBUTE_UNUSED
,
9821 machine_mode known_mode ATTRIBUTE_UNUSED
,
9822 unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED
,
9823 unsigned HOST_WIDE_INT
*nonzero
)
9828 /* If X is a register whose nonzero bits value is current, use it.
9829 Otherwise, if X is a register whose value we can find, use that
9830 value. Otherwise, use the previously-computed global nonzero bits
9831 for this register. */
9833 rsp
= ®_stat
[REGNO (x
)];
9834 if (rsp
->last_set_value
!= 0
9835 && (rsp
->last_set_mode
== mode
9836 || (GET_MODE_CLASS (rsp
->last_set_mode
) == MODE_INT
9837 && GET_MODE_CLASS (mode
) == MODE_INT
))
9838 && ((rsp
->last_set_label
>= label_tick_ebb_start
9839 && rsp
->last_set_label
< label_tick
)
9840 || (rsp
->last_set_label
== label_tick
9841 && DF_INSN_LUID (rsp
->last_set
) < subst_low_luid
)
9842 || (REGNO (x
) >= FIRST_PSEUDO_REGISTER
9843 && REGNO (x
) < reg_n_sets_max
9844 && REG_N_SETS (REGNO (x
)) == 1
9846 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
9849 unsigned HOST_WIDE_INT mask
= rsp
->last_set_nonzero_bits
;
9851 if (GET_MODE_PRECISION (rsp
->last_set_mode
) < GET_MODE_PRECISION (mode
))
9852 /* We don't know anything about the upper bits. */
9853 mask
|= GET_MODE_MASK (mode
) ^ GET_MODE_MASK (rsp
->last_set_mode
);
9859 tem
= get_last_value (x
);
9863 if (SHORT_IMMEDIATES_SIGN_EXTEND
)
9864 tem
= sign_extend_short_imm (tem
, GET_MODE (x
),
9865 GET_MODE_PRECISION (mode
));
9869 else if (nonzero_sign_valid
&& rsp
->nonzero_bits
)
9871 unsigned HOST_WIDE_INT mask
= rsp
->nonzero_bits
;
9873 if (GET_MODE_PRECISION (GET_MODE (x
)) < GET_MODE_PRECISION (mode
))
9874 /* We don't know anything about the upper bits. */
9875 mask
|= GET_MODE_MASK (mode
) ^ GET_MODE_MASK (GET_MODE (x
));
9883 /* Return the number of bits at the high-order end of X that are known to
9884 be equal to the sign bit. X will be used in mode MODE; if MODE is
9885 VOIDmode, X will be used in its own mode. The returned value will always
9886 be between 1 and the number of bits in MODE. */
9889 reg_num_sign_bit_copies_for_combine (const_rtx x
, machine_mode mode
,
9890 const_rtx known_x ATTRIBUTE_UNUSED
,
9891 machine_mode known_mode
9893 unsigned int known_ret ATTRIBUTE_UNUSED
,
9894 unsigned int *result
)
9899 rsp
= ®_stat
[REGNO (x
)];
9900 if (rsp
->last_set_value
!= 0
9901 && rsp
->last_set_mode
== mode
9902 && ((rsp
->last_set_label
>= label_tick_ebb_start
9903 && rsp
->last_set_label
< label_tick
)
9904 || (rsp
->last_set_label
== label_tick
9905 && DF_INSN_LUID (rsp
->last_set
) < subst_low_luid
)
9906 || (REGNO (x
) >= FIRST_PSEUDO_REGISTER
9907 && REGNO (x
) < reg_n_sets_max
9908 && REG_N_SETS (REGNO (x
)) == 1
9910 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
9913 *result
= rsp
->last_set_sign_bit_copies
;
9917 tem
= get_last_value (x
);
9921 if (nonzero_sign_valid
&& rsp
->sign_bit_copies
!= 0
9922 && GET_MODE_PRECISION (GET_MODE (x
)) == GET_MODE_PRECISION (mode
))
9923 *result
= rsp
->sign_bit_copies
;
9928 /* Return the number of "extended" bits there are in X, when interpreted
9929 as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For
9930 unsigned quantities, this is the number of high-order zero bits.
9931 For signed quantities, this is the number of copies of the sign bit
9932 minus 1. In both case, this function returns the number of "spare"
9933 bits. For example, if two quantities for which this function returns
9934 at least 1 are added, the addition is known not to overflow.
9936 This function will always return 0 unless called during combine, which
9937 implies that it must be called from a define_split. */
9940 extended_count (const_rtx x
, machine_mode mode
, int unsignedp
)
9942 if (nonzero_sign_valid
== 0)
9946 ? (HWI_COMPUTABLE_MODE_P (mode
)
9947 ? (unsigned int) (GET_MODE_PRECISION (mode
) - 1
9948 - floor_log2 (nonzero_bits (x
, mode
)))
9950 : num_sign_bit_copies (x
, mode
) - 1);
9953 /* This function is called from `simplify_shift_const' to merge two
9954 outer operations. Specifically, we have already found that we need
9955 to perform operation *POP0 with constant *PCONST0 at the outermost
9956 position. We would now like to also perform OP1 with constant CONST1
9957 (with *POP0 being done last).
9959 Return 1 if we can do the operation and update *POP0 and *PCONST0 with
9960 the resulting operation. *PCOMP_P is set to 1 if we would need to
9961 complement the innermost operand, otherwise it is unchanged.
9963 MODE is the mode in which the operation will be done. No bits outside
9964 the width of this mode matter. It is assumed that the width of this mode
9965 is smaller than or equal to HOST_BITS_PER_WIDE_INT.
9967 If *POP0 or OP1 are UNKNOWN, it means no operation is required. Only NEG, PLUS,
9968 IOR, XOR, and AND are supported. We may set *POP0 to SET if the proper
9969 result is simply *PCONST0.
9971 If the resulting operation cannot be expressed as one operation, we
9972 return 0 and do not change *POP0, *PCONST0, and *PCOMP_P. */
9975 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
)
9977 enum rtx_code op0
= *pop0
;
9978 HOST_WIDE_INT const0
= *pconst0
;
9980 const0
&= GET_MODE_MASK (mode
);
9981 const1
&= GET_MODE_MASK (mode
);
9983 /* If OP0 is an AND, clear unimportant bits in CONST1. */
9987 /* If OP0 or OP1 is UNKNOWN, this is easy. Similarly if they are the same or
9990 if (op1
== UNKNOWN
|| op0
== SET
)
9993 else if (op0
== UNKNOWN
)
9994 op0
= op1
, const0
= const1
;
9996 else if (op0
== op1
)
10020 /* Otherwise, if either is a PLUS or NEG, we can't do anything. */
10021 else if (op0
== PLUS
|| op1
== PLUS
|| op0
== NEG
|| op1
== NEG
)
10024 /* If the two constants aren't the same, we can't do anything. The
10025 remaining six cases can all be done. */
10026 else if (const0
!= const1
)
10034 /* (a & b) | b == b */
10036 else /* op1 == XOR */
10037 /* (a ^ b) | b == a | b */
10043 /* (a & b) ^ b == (~a) & b */
10044 op0
= AND
, *pcomp_p
= 1;
10045 else /* op1 == IOR */
10046 /* (a | b) ^ b == a & ~b */
10047 op0
= AND
, const0
= ~const0
;
10052 /* (a | b) & b == b */
10054 else /* op1 == XOR */
10055 /* (a ^ b) & b) == (~a) & b */
10062 /* Check for NO-OP cases. */
10063 const0
&= GET_MODE_MASK (mode
);
10065 && (op0
== IOR
|| op0
== XOR
|| op0
== PLUS
))
10067 else if (const0
== 0 && op0
== AND
)
10069 else if ((unsigned HOST_WIDE_INT
) const0
== GET_MODE_MASK (mode
)
10075 /* ??? Slightly redundant with the above mask, but not entirely.
10076 Moving this above means we'd have to sign-extend the mode mask
10077 for the final test. */
10078 if (op0
!= UNKNOWN
&& op0
!= NEG
)
10079 *pconst0
= trunc_int_for_mode (const0
, mode
);
10084 /* A helper to simplify_shift_const_1 to determine the mode we can perform
10085 the shift in. The original shift operation CODE is performed on OP in
10086 ORIG_MODE. Return the wider mode MODE if we can perform the operation
10087 in that mode. Return ORIG_MODE otherwise. We can also assume that the
10088 result of the shift is subject to operation OUTER_CODE with operand
10091 static machine_mode
10092 try_widen_shift_mode (enum rtx_code code
, rtx op
, int count
,
10093 machine_mode orig_mode
, machine_mode mode
,
10094 enum rtx_code outer_code
, HOST_WIDE_INT outer_const
)
10096 if (orig_mode
== mode
)
10098 gcc_assert (GET_MODE_PRECISION (mode
) > GET_MODE_PRECISION (orig_mode
));
10100 /* In general we can't perform in wider mode for right shift and rotate. */
10104 /* We can still widen if the bits brought in from the left are identical
10105 to the sign bit of ORIG_MODE. */
10106 if (num_sign_bit_copies (op
, mode
)
10107 > (unsigned) (GET_MODE_PRECISION (mode
)
10108 - GET_MODE_PRECISION (orig_mode
)))
10113 /* Similarly here but with zero bits. */
10114 if (HWI_COMPUTABLE_MODE_P (mode
)
10115 && (nonzero_bits (op
, mode
) & ~GET_MODE_MASK (orig_mode
)) == 0)
10118 /* We can also widen if the bits brought in will be masked off. This
10119 operation is performed in ORIG_MODE. */
10120 if (outer_code
== AND
)
10122 int care_bits
= low_bitmask_len (orig_mode
, outer_const
);
10125 && GET_MODE_PRECISION (orig_mode
) - care_bits
>= count
)
10134 gcc_unreachable ();
10141 /* Simplify a shift of VAROP by ORIG_COUNT bits. CODE says what kind
10142 of shift. The result of the shift is RESULT_MODE. Return NULL_RTX
10143 if we cannot simplify it. Otherwise, return a simplified value.
10145 The shift is normally computed in the widest mode we find in VAROP, as
10146 long as it isn't a different number of words than RESULT_MODE. Exceptions
10147 are ASHIFTRT and ROTATE, which are always done in their original mode. */
10150 simplify_shift_const_1 (enum rtx_code code
, machine_mode result_mode
,
10151 rtx varop
, int orig_count
)
10153 enum rtx_code orig_code
= code
;
10154 rtx orig_varop
= varop
;
10156 machine_mode mode
= result_mode
;
10157 machine_mode shift_mode
, tmode
;
10158 unsigned int mode_words
10159 = (GET_MODE_SIZE (mode
) + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
;
10160 /* We form (outer_op (code varop count) (outer_const)). */
10161 enum rtx_code outer_op
= UNKNOWN
;
10162 HOST_WIDE_INT outer_const
= 0;
10163 int complement_p
= 0;
10166 /* Make sure and truncate the "natural" shift on the way in. We don't
10167 want to do this inside the loop as it makes it more difficult to
10169 if (SHIFT_COUNT_TRUNCATED
)
10170 orig_count
&= GET_MODE_BITSIZE (mode
) - 1;
10172 /* If we were given an invalid count, don't do anything except exactly
10173 what was requested. */
10175 if (orig_count
< 0 || orig_count
>= (int) GET_MODE_PRECISION (mode
))
10178 count
= orig_count
;
10180 /* Unless one of the branches of the `if' in this loop does a `continue',
10181 we will `break' the loop after the `if'. */
10185 /* If we have an operand of (clobber (const_int 0)), fail. */
10186 if (GET_CODE (varop
) == CLOBBER
)
10189 /* Convert ROTATERT to ROTATE. */
10190 if (code
== ROTATERT
)
10192 unsigned int bitsize
= GET_MODE_PRECISION (result_mode
);
10194 if (VECTOR_MODE_P (result_mode
))
10195 count
= bitsize
/ GET_MODE_NUNITS (result_mode
) - count
;
10197 count
= bitsize
- count
;
10200 shift_mode
= try_widen_shift_mode (code
, varop
, count
, result_mode
,
10201 mode
, outer_op
, outer_const
);
10203 /* Handle cases where the count is greater than the size of the mode
10204 minus 1. For ASHIFT, use the size minus one as the count (this can
10205 occur when simplifying (lshiftrt (ashiftrt ..))). For rotates,
10206 take the count modulo the size. For other shifts, the result is
10209 Since these shifts are being produced by the compiler by combining
10210 multiple operations, each of which are defined, we know what the
10211 result is supposed to be. */
10213 if (count
> (GET_MODE_PRECISION (shift_mode
) - 1))
10215 if (code
== ASHIFTRT
)
10216 count
= GET_MODE_PRECISION (shift_mode
) - 1;
10217 else if (code
== ROTATE
|| code
== ROTATERT
)
10218 count
%= GET_MODE_PRECISION (shift_mode
);
10221 /* We can't simply return zero because there may be an
10223 varop
= const0_rtx
;
10229 /* If we discovered we had to complement VAROP, leave. Making a NOT
10230 here would cause an infinite loop. */
10234 /* An arithmetic right shift of a quantity known to be -1 or 0
10236 if (code
== ASHIFTRT
10237 && (num_sign_bit_copies (varop
, shift_mode
)
10238 == GET_MODE_PRECISION (shift_mode
)))
10244 /* If we are doing an arithmetic right shift and discarding all but
10245 the sign bit copies, this is equivalent to doing a shift by the
10246 bitsize minus one. Convert it into that shift because it will often
10247 allow other simplifications. */
10249 if (code
== ASHIFTRT
10250 && (count
+ num_sign_bit_copies (varop
, shift_mode
)
10251 >= GET_MODE_PRECISION (shift_mode
)))
10252 count
= GET_MODE_PRECISION (shift_mode
) - 1;
10254 /* We simplify the tests below and elsewhere by converting
10255 ASHIFTRT to LSHIFTRT if we know the sign bit is clear.
10256 `make_compound_operation' will convert it to an ASHIFTRT for
10257 those machines (such as VAX) that don't have an LSHIFTRT. */
10258 if (code
== ASHIFTRT
10259 && val_signbit_known_clear_p (shift_mode
,
10260 nonzero_bits (varop
, shift_mode
)))
10263 if (((code
== LSHIFTRT
10264 && HWI_COMPUTABLE_MODE_P (shift_mode
)
10265 && !(nonzero_bits (varop
, shift_mode
) >> count
))
10267 && HWI_COMPUTABLE_MODE_P (shift_mode
)
10268 && !((nonzero_bits (varop
, shift_mode
) << count
)
10269 & GET_MODE_MASK (shift_mode
))))
10270 && !side_effects_p (varop
))
10271 varop
= const0_rtx
;
10273 switch (GET_CODE (varop
))
10279 new_rtx
= expand_compound_operation (varop
);
10280 if (new_rtx
!= varop
)
10288 /* If we have (xshiftrt (mem ...) C) and C is MODE_WIDTH
10289 minus the width of a smaller mode, we can do this with a
10290 SIGN_EXTEND or ZERO_EXTEND from the narrower memory location. */
10291 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10292 && ! mode_dependent_address_p (XEXP (varop
, 0),
10293 MEM_ADDR_SPACE (varop
))
10294 && ! MEM_VOLATILE_P (varop
)
10295 && (tmode
= mode_for_size (GET_MODE_BITSIZE (mode
) - count
,
10296 MODE_INT
, 1)) != BLKmode
)
10298 new_rtx
= adjust_address_nv (varop
, tmode
,
10299 BYTES_BIG_ENDIAN
? 0
10300 : count
/ BITS_PER_UNIT
);
10302 varop
= gen_rtx_fmt_e (code
== ASHIFTRT
? SIGN_EXTEND
10303 : ZERO_EXTEND
, mode
, new_rtx
);
10310 /* If VAROP is a SUBREG, strip it as long as the inner operand has
10311 the same number of words as what we've seen so far. Then store
10312 the widest mode in MODE. */
10313 if (subreg_lowpart_p (varop
)
10314 && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
10315 > GET_MODE_SIZE (GET_MODE (varop
)))
10316 && (unsigned int) ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
10317 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
10319 && GET_MODE_CLASS (GET_MODE (varop
)) == MODE_INT
10320 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (varop
))) == MODE_INT
)
10322 varop
= SUBREG_REG (varop
);
10323 if (GET_MODE_SIZE (GET_MODE (varop
)) > GET_MODE_SIZE (mode
))
10324 mode
= GET_MODE (varop
);
10330 /* Some machines use MULT instead of ASHIFT because MULT
10331 is cheaper. But it is still better on those machines to
10332 merge two shifts into one. */
10333 if (CONST_INT_P (XEXP (varop
, 1))
10334 && exact_log2 (UINTVAL (XEXP (varop
, 1))) >= 0)
10337 = simplify_gen_binary (ASHIFT
, GET_MODE (varop
),
10339 GEN_INT (exact_log2 (
10340 UINTVAL (XEXP (varop
, 1)))));
10346 /* Similar, for when divides are cheaper. */
10347 if (CONST_INT_P (XEXP (varop
, 1))
10348 && exact_log2 (UINTVAL (XEXP (varop
, 1))) >= 0)
10351 = simplify_gen_binary (LSHIFTRT
, GET_MODE (varop
),
10353 GEN_INT (exact_log2 (
10354 UINTVAL (XEXP (varop
, 1)))));
10360 /* If we are extracting just the sign bit of an arithmetic
10361 right shift, that shift is not needed. However, the sign
10362 bit of a wider mode may be different from what would be
10363 interpreted as the sign bit in a narrower mode, so, if
10364 the result is narrower, don't discard the shift. */
10365 if (code
== LSHIFTRT
10366 && count
== (GET_MODE_BITSIZE (result_mode
) - 1)
10367 && (GET_MODE_BITSIZE (result_mode
)
10368 >= GET_MODE_BITSIZE (GET_MODE (varop
))))
10370 varop
= XEXP (varop
, 0);
10374 /* ... fall through ... */
10379 /* Here we have two nested shifts. The result is usually the
10380 AND of a new shift with a mask. We compute the result below. */
10381 if (CONST_INT_P (XEXP (varop
, 1))
10382 && INTVAL (XEXP (varop
, 1)) >= 0
10383 && INTVAL (XEXP (varop
, 1)) < GET_MODE_PRECISION (GET_MODE (varop
))
10384 && HWI_COMPUTABLE_MODE_P (result_mode
)
10385 && HWI_COMPUTABLE_MODE_P (mode
)
10386 && !VECTOR_MODE_P (result_mode
))
10388 enum rtx_code first_code
= GET_CODE (varop
);
10389 unsigned int first_count
= INTVAL (XEXP (varop
, 1));
10390 unsigned HOST_WIDE_INT mask
;
10393 /* We have one common special case. We can't do any merging if
10394 the inner code is an ASHIFTRT of a smaller mode. However, if
10395 we have (ashift:M1 (subreg:M1 (ashiftrt:M2 FOO C1) 0) C2)
10396 with C2 == GET_MODE_BITSIZE (M1) - GET_MODE_BITSIZE (M2),
10397 we can convert it to
10398 (ashiftrt:M1 (ashift:M1 (and:M1 (subreg:M1 FOO 0) C3) C2) C1).
10399 This simplifies certain SIGN_EXTEND operations. */
10400 if (code
== ASHIFT
&& first_code
== ASHIFTRT
10401 && count
== (GET_MODE_PRECISION (result_mode
)
10402 - GET_MODE_PRECISION (GET_MODE (varop
))))
10404 /* C3 has the low-order C1 bits zero. */
10406 mask
= GET_MODE_MASK (mode
)
10407 & ~(((unsigned HOST_WIDE_INT
) 1 << first_count
) - 1);
10409 varop
= simplify_and_const_int (NULL_RTX
, result_mode
,
10410 XEXP (varop
, 0), mask
);
10411 varop
= simplify_shift_const (NULL_RTX
, ASHIFT
, result_mode
,
10413 count
= first_count
;
10418 /* If this was (ashiftrt (ashift foo C1) C2) and FOO has more
10419 than C1 high-order bits equal to the sign bit, we can convert
10420 this to either an ASHIFT or an ASHIFTRT depending on the
10423 We cannot do this if VAROP's mode is not SHIFT_MODE. */
10425 if (code
== ASHIFTRT
&& first_code
== ASHIFT
10426 && GET_MODE (varop
) == shift_mode
10427 && (num_sign_bit_copies (XEXP (varop
, 0), shift_mode
)
10430 varop
= XEXP (varop
, 0);
10431 count
-= first_count
;
10441 /* There are some cases we can't do. If CODE is ASHIFTRT,
10442 we can only do this if FIRST_CODE is also ASHIFTRT.
10444 We can't do the case when CODE is ROTATE and FIRST_CODE is
10447 If the mode of this shift is not the mode of the outer shift,
10448 we can't do this if either shift is a right shift or ROTATE.
10450 Finally, we can't do any of these if the mode is too wide
10451 unless the codes are the same.
10453 Handle the case where the shift codes are the same
10456 if (code
== first_code
)
10458 if (GET_MODE (varop
) != result_mode
10459 && (code
== ASHIFTRT
|| code
== LSHIFTRT
10460 || code
== ROTATE
))
10463 count
+= first_count
;
10464 varop
= XEXP (varop
, 0);
10468 if (code
== ASHIFTRT
10469 || (code
== ROTATE
&& first_code
== ASHIFTRT
)
10470 || GET_MODE_PRECISION (mode
) > HOST_BITS_PER_WIDE_INT
10471 || (GET_MODE (varop
) != result_mode
10472 && (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
10473 || first_code
== ROTATE
10474 || code
== ROTATE
)))
10477 /* To compute the mask to apply after the shift, shift the
10478 nonzero bits of the inner shift the same way the
10479 outer shift will. */
10481 mask_rtx
= gen_int_mode (nonzero_bits (varop
, GET_MODE (varop
)),
10485 = simplify_const_binary_operation (code
, result_mode
, mask_rtx
,
10488 /* Give up if we can't compute an outer operation to use. */
10490 || !CONST_INT_P (mask_rtx
)
10491 || ! merge_outer_ops (&outer_op
, &outer_const
, AND
,
10493 result_mode
, &complement_p
))
10496 /* If the shifts are in the same direction, we add the
10497 counts. Otherwise, we subtract them. */
10498 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10499 == (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
))
10500 count
+= first_count
;
10502 count
-= first_count
;
10504 /* If COUNT is positive, the new shift is usually CODE,
10505 except for the two exceptions below, in which case it is
10506 FIRST_CODE. If the count is negative, FIRST_CODE should
10509 && ((first_code
== ROTATE
&& code
== ASHIFT
)
10510 || (first_code
== ASHIFTRT
&& code
== LSHIFTRT
)))
10512 else if (count
< 0)
10513 code
= first_code
, count
= -count
;
10515 varop
= XEXP (varop
, 0);
10519 /* If we have (A << B << C) for any shift, we can convert this to
10520 (A << C << B). This wins if A is a constant. Only try this if
10521 B is not a constant. */
10523 else if (GET_CODE (varop
) == code
10524 && CONST_INT_P (XEXP (varop
, 0))
10525 && !CONST_INT_P (XEXP (varop
, 1)))
10527 /* For ((unsigned) (cstULL >> count)) >> cst2 we have to make
10528 sure the result will be masked. See PR70222. */
10529 if (code
== LSHIFTRT
10530 && mode
!= result_mode
10531 && !merge_outer_ops (&outer_op
, &outer_const
, AND
,
10532 GET_MODE_MASK (result_mode
)
10533 >> orig_count
, result_mode
,
10536 /* For ((int) (cstLL >> count)) >> cst2 just give up. Queuing
10537 up outer sign extension (often left and right shift) is
10538 hardly more efficient than the original. See PR70429. */
10539 if (code
== ASHIFTRT
&& mode
!= result_mode
)
10542 rtx new_rtx
= simplify_const_binary_operation (code
, mode
,
10545 varop
= gen_rtx_fmt_ee (code
, mode
, new_rtx
, XEXP (varop
, 1));
10552 if (VECTOR_MODE_P (mode
))
10555 /* Make this fit the case below. */
10556 varop
= gen_rtx_XOR (mode
, XEXP (varop
, 0), constm1_rtx
);
10562 /* If we have (xshiftrt (ior (plus X (const_int -1)) X) C)
10563 with C the size of VAROP - 1 and the shift is logical if
10564 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
10565 we have an (le X 0) operation. If we have an arithmetic shift
10566 and STORE_FLAG_VALUE is 1 or we have a logical shift with
10567 STORE_FLAG_VALUE of -1, we have a (neg (le X 0)) operation. */
10569 if (GET_CODE (varop
) == IOR
&& GET_CODE (XEXP (varop
, 0)) == PLUS
10570 && XEXP (XEXP (varop
, 0), 1) == constm1_rtx
10571 && (STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
10572 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
10573 && count
== (GET_MODE_PRECISION (GET_MODE (varop
)) - 1)
10574 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
10577 varop
= gen_rtx_LE (GET_MODE (varop
), XEXP (varop
, 1),
10580 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
10581 varop
= gen_rtx_NEG (GET_MODE (varop
), varop
);
10586 /* If we have (shift (logical)), move the logical to the outside
10587 to allow it to possibly combine with another logical and the
10588 shift to combine with another shift. This also canonicalizes to
10589 what a ZERO_EXTRACT looks like. Also, some machines have
10590 (and (shift)) insns. */
10592 if (CONST_INT_P (XEXP (varop
, 1))
10593 /* We can't do this if we have (ashiftrt (xor)) and the
10594 constant has its sign bit set in shift_mode with shift_mode
10595 wider than result_mode. */
10596 && !(code
== ASHIFTRT
&& GET_CODE (varop
) == XOR
10597 && result_mode
!= shift_mode
10598 && 0 > trunc_int_for_mode (INTVAL (XEXP (varop
, 1)),
10600 && (new_rtx
= simplify_const_binary_operation
10601 (code
, result_mode
,
10602 gen_int_mode (INTVAL (XEXP (varop
, 1)), result_mode
),
10603 GEN_INT (count
))) != 0
10604 && CONST_INT_P (new_rtx
)
10605 && merge_outer_ops (&outer_op
, &outer_const
, GET_CODE (varop
),
10606 INTVAL (new_rtx
), result_mode
, &complement_p
))
10608 varop
= XEXP (varop
, 0);
10612 /* If we can't do that, try to simplify the shift in each arm of the
10613 logical expression, make a new logical expression, and apply
10614 the inverse distributive law. This also can't be done for
10615 (ashiftrt (xor)) where we've widened the shift and the constant
10616 changes the sign bit. */
10617 if (CONST_INT_P (XEXP (varop
, 1))
10618 && !(code
== ASHIFTRT
&& GET_CODE (varop
) == XOR
10619 && result_mode
!= shift_mode
10620 && 0 > trunc_int_for_mode (INTVAL (XEXP (varop
, 1)),
10623 rtx lhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
10624 XEXP (varop
, 0), count
);
10625 rtx rhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
10626 XEXP (varop
, 1), count
);
10628 varop
= simplify_gen_binary (GET_CODE (varop
), shift_mode
,
10630 varop
= apply_distributive_law (varop
);
10638 /* Convert (lshiftrt (eq FOO 0) C) to (xor FOO 1) if STORE_FLAG_VALUE
10639 says that the sign bit can be tested, FOO has mode MODE, C is
10640 GET_MODE_PRECISION (MODE) - 1, and FOO has only its low-order bit
10641 that may be nonzero. */
10642 if (code
== LSHIFTRT
10643 && XEXP (varop
, 1) == const0_rtx
10644 && GET_MODE (XEXP (varop
, 0)) == result_mode
10645 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10646 && HWI_COMPUTABLE_MODE_P (result_mode
)
10647 && STORE_FLAG_VALUE
== -1
10648 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
10649 && merge_outer_ops (&outer_op
, &outer_const
, XOR
, 1, result_mode
,
10652 varop
= XEXP (varop
, 0);
10659 /* (lshiftrt (neg A) C) where A is either 0 or 1 and C is one less
10660 than the number of bits in the mode is equivalent to A. */
10661 if (code
== LSHIFTRT
10662 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10663 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1)
10665 varop
= XEXP (varop
, 0);
10670 /* NEG commutes with ASHIFT since it is multiplication. Move the
10671 NEG outside to allow shifts to combine. */
10673 && merge_outer_ops (&outer_op
, &outer_const
, NEG
, 0, result_mode
,
10676 varop
= XEXP (varop
, 0);
10682 /* (lshiftrt (plus A -1) C) where A is either 0 or 1 and C
10683 is one less than the number of bits in the mode is
10684 equivalent to (xor A 1). */
10685 if (code
== LSHIFTRT
10686 && count
== (GET_MODE_PRECISION (result_mode
) - 1)
10687 && XEXP (varop
, 1) == constm1_rtx
10688 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
10689 && merge_outer_ops (&outer_op
, &outer_const
, XOR
, 1, result_mode
,
10693 varop
= XEXP (varop
, 0);
10697 /* If we have (xshiftrt (plus FOO BAR) C), and the only bits
10698 that might be nonzero in BAR are those being shifted out and those
10699 bits are known zero in FOO, we can replace the PLUS with FOO.
10700 Similarly in the other operand order. This code occurs when
10701 we are computing the size of a variable-size array. */
10703 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10704 && count
< HOST_BITS_PER_WIDE_INT
10705 && nonzero_bits (XEXP (varop
, 1), result_mode
) >> count
== 0
10706 && (nonzero_bits (XEXP (varop
, 1), result_mode
)
10707 & nonzero_bits (XEXP (varop
, 0), result_mode
)) == 0)
10709 varop
= XEXP (varop
, 0);
10712 else if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
10713 && count
< HOST_BITS_PER_WIDE_INT
10714 && HWI_COMPUTABLE_MODE_P (result_mode
)
10715 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
10717 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
10718 & nonzero_bits (XEXP (varop
, 1),
10721 varop
= XEXP (varop
, 1);
10725 /* (ashift (plus foo C) N) is (plus (ashift foo N) C'). */
10727 && CONST_INT_P (XEXP (varop
, 1))
10728 && (new_rtx
= simplify_const_binary_operation
10729 (ASHIFT
, result_mode
,
10730 gen_int_mode (INTVAL (XEXP (varop
, 1)), result_mode
),
10731 GEN_INT (count
))) != 0
10732 && CONST_INT_P (new_rtx
)
10733 && merge_outer_ops (&outer_op
, &outer_const
, PLUS
,
10734 INTVAL (new_rtx
), result_mode
, &complement_p
))
10736 varop
= XEXP (varop
, 0);
10740 /* Check for 'PLUS signbit', which is the canonical form of 'XOR
10741 signbit', and attempt to change the PLUS to an XOR and move it to
10742 the outer operation as is done above in the AND/IOR/XOR case
10743 leg for shift(logical). See details in logical handling above
10744 for reasoning in doing so. */
10745 if (code
== LSHIFTRT
10746 && CONST_INT_P (XEXP (varop
, 1))
10747 && mode_signbit_p (result_mode
, 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
, XOR
,
10754 INTVAL (new_rtx
), result_mode
, &complement_p
))
10756 varop
= XEXP (varop
, 0);
10763 /* If we have (xshiftrt (minus (ashiftrt X C)) X) C)
10764 with C the size of VAROP - 1 and the shift is logical if
10765 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
10766 we have a (gt X 0) operation. If the shift is arithmetic with
10767 STORE_FLAG_VALUE of 1 or logical with STORE_FLAG_VALUE == -1,
10768 we have a (neg (gt X 0)) operation. */
10770 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
10771 && GET_CODE (XEXP (varop
, 0)) == ASHIFTRT
10772 && count
== (GET_MODE_PRECISION (GET_MODE (varop
)) - 1)
10773 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
10774 && CONST_INT_P (XEXP (XEXP (varop
, 0), 1))
10775 && INTVAL (XEXP (XEXP (varop
, 0), 1)) == count
10776 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
10779 varop
= gen_rtx_GT (GET_MODE (varop
), XEXP (varop
, 1),
10782 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
10783 varop
= gen_rtx_NEG (GET_MODE (varop
), varop
);
10790 /* Change (lshiftrt (truncate (lshiftrt))) to (truncate (lshiftrt))
10791 if the truncate does not affect the value. */
10792 if (code
== LSHIFTRT
10793 && GET_CODE (XEXP (varop
, 0)) == LSHIFTRT
10794 && CONST_INT_P (XEXP (XEXP (varop
, 0), 1))
10795 && (INTVAL (XEXP (XEXP (varop
, 0), 1))
10796 >= (GET_MODE_PRECISION (GET_MODE (XEXP (varop
, 0)))
10797 - GET_MODE_PRECISION (GET_MODE (varop
)))))
10799 rtx varop_inner
= XEXP (varop
, 0);
10802 = gen_rtx_LSHIFTRT (GET_MODE (varop_inner
),
10803 XEXP (varop_inner
, 0),
10805 (count
+ INTVAL (XEXP (varop_inner
, 1))));
10806 varop
= gen_rtx_TRUNCATE (GET_MODE (varop
), varop_inner
);
10819 shift_mode
= try_widen_shift_mode (code
, varop
, count
, result_mode
, mode
,
10820 outer_op
, outer_const
);
10822 /* We have now finished analyzing the shift. The result should be
10823 a shift of type CODE with SHIFT_MODE shifting VAROP COUNT places. If
10824 OUTER_OP is non-UNKNOWN, it is an operation that needs to be applied
10825 to the result of the shift. OUTER_CONST is the relevant constant,
10826 but we must turn off all bits turned off in the shift. */
10828 if (outer_op
== UNKNOWN
10829 && orig_code
== code
&& orig_count
== count
10830 && varop
== orig_varop
10831 && shift_mode
== GET_MODE (varop
))
10834 /* Make a SUBREG if necessary. If we can't make it, fail. */
10835 varop
= gen_lowpart (shift_mode
, varop
);
10836 if (varop
== NULL_RTX
|| GET_CODE (varop
) == CLOBBER
)
10839 /* If we have an outer operation and we just made a shift, it is
10840 possible that we could have simplified the shift were it not
10841 for the outer operation. So try to do the simplification
10844 if (outer_op
!= UNKNOWN
)
10845 x
= simplify_shift_const_1 (code
, shift_mode
, varop
, count
);
10850 x
= simplify_gen_binary (code
, shift_mode
, varop
, GEN_INT (count
));
10852 /* If we were doing an LSHIFTRT in a wider mode than it was originally,
10853 turn off all the bits that the shift would have turned off. */
10854 if (orig_code
== LSHIFTRT
&& result_mode
!= shift_mode
)
10855 x
= simplify_and_const_int (NULL_RTX
, shift_mode
, x
,
10856 GET_MODE_MASK (result_mode
) >> orig_count
);
10858 /* Do the remainder of the processing in RESULT_MODE. */
10859 x
= gen_lowpart_or_truncate (result_mode
, x
);
10861 /* If COMPLEMENT_P is set, we have to complement X before doing the outer
10864 x
= simplify_gen_unary (NOT
, result_mode
, x
, result_mode
);
10866 if (outer_op
!= UNKNOWN
)
10868 if (GET_RTX_CLASS (outer_op
) != RTX_UNARY
10869 && GET_MODE_PRECISION (result_mode
) < HOST_BITS_PER_WIDE_INT
)
10870 outer_const
= trunc_int_for_mode (outer_const
, result_mode
);
10872 if (outer_op
== AND
)
10873 x
= simplify_and_const_int (NULL_RTX
, result_mode
, x
, outer_const
);
10874 else if (outer_op
== SET
)
10876 /* This means that we have determined that the result is
10877 equivalent to a constant. This should be rare. */
10878 if (!side_effects_p (x
))
10879 x
= GEN_INT (outer_const
);
10881 else if (GET_RTX_CLASS (outer_op
) == RTX_UNARY
)
10882 x
= simplify_gen_unary (outer_op
, result_mode
, x
, result_mode
);
10884 x
= simplify_gen_binary (outer_op
, result_mode
, x
,
10885 GEN_INT (outer_const
));
10891 /* Simplify a shift of VAROP by COUNT bits. CODE says what kind of shift.
10892 The result of the shift is RESULT_MODE. If we cannot simplify it,
10893 return X or, if it is NULL, synthesize the expression with
10894 simplify_gen_binary. Otherwise, return a simplified value.
10896 The shift is normally computed in the widest mode we find in VAROP, as
10897 long as it isn't a different number of words than RESULT_MODE. Exceptions
10898 are ASHIFTRT and ROTATE, which are always done in their original mode. */
10901 simplify_shift_const (rtx x
, enum rtx_code code
, machine_mode result_mode
,
10902 rtx varop
, int count
)
10904 rtx tem
= simplify_shift_const_1 (code
, result_mode
, varop
, count
);
10909 x
= simplify_gen_binary (code
, GET_MODE (varop
), varop
, GEN_INT (count
));
10910 if (GET_MODE (x
) != result_mode
)
10911 x
= gen_lowpart (result_mode
, x
);
10916 /* A subroutine of recog_for_combine. See there for arguments and
10920 recog_for_combine_1 (rtx
*pnewpat
, rtx_insn
*insn
, rtx
*pnotes
)
10922 rtx pat
= *pnewpat
;
10923 rtx pat_without_clobbers
;
10924 int insn_code_number
;
10925 int num_clobbers_to_add
= 0;
10927 rtx notes
= NULL_RTX
;
10928 rtx old_notes
, old_pat
;
10931 /* If PAT is a PARALLEL, check to see if it contains the CLOBBER
10932 we use to indicate that something didn't match. If we find such a
10933 thing, force rejection. */
10934 if (GET_CODE (pat
) == PARALLEL
)
10935 for (i
= XVECLEN (pat
, 0) - 1; i
>= 0; i
--)
10936 if (GET_CODE (XVECEXP (pat
, 0, i
)) == CLOBBER
10937 && XEXP (XVECEXP (pat
, 0, i
), 0) == const0_rtx
)
10940 old_pat
= PATTERN (insn
);
10941 old_notes
= REG_NOTES (insn
);
10942 PATTERN (insn
) = pat
;
10943 REG_NOTES (insn
) = NULL_RTX
;
10945 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
10946 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
10948 if (insn_code_number
< 0)
10949 fputs ("Failed to match this instruction:\n", dump_file
);
10951 fputs ("Successfully matched this instruction:\n", dump_file
);
10952 print_rtl_single (dump_file
, pat
);
10955 /* If it isn't, there is the possibility that we previously had an insn
10956 that clobbered some register as a side effect, but the combined
10957 insn doesn't need to do that. So try once more without the clobbers
10958 unless this represents an ASM insn. */
10960 if (insn_code_number
< 0 && ! check_asm_operands (pat
)
10961 && GET_CODE (pat
) == PARALLEL
)
10965 for (pos
= 0, i
= 0; i
< XVECLEN (pat
, 0); i
++)
10966 if (GET_CODE (XVECEXP (pat
, 0, i
)) != CLOBBER
)
10969 SUBST (XVECEXP (pat
, 0, pos
), XVECEXP (pat
, 0, i
));
10973 SUBST_INT (XVECLEN (pat
, 0), pos
);
10976 pat
= XVECEXP (pat
, 0, 0);
10978 PATTERN (insn
) = pat
;
10979 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
10980 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
10982 if (insn_code_number
< 0)
10983 fputs ("Failed to match this instruction:\n", dump_file
);
10985 fputs ("Successfully matched this instruction:\n", dump_file
);
10986 print_rtl_single (dump_file
, pat
);
10990 pat_without_clobbers
= pat
;
10992 PATTERN (insn
) = old_pat
;
10993 REG_NOTES (insn
) = old_notes
;
10995 /* Recognize all noop sets, these will be killed by followup pass. */
10996 if (insn_code_number
< 0 && GET_CODE (pat
) == SET
&& set_noop_p (pat
))
10997 insn_code_number
= NOOP_MOVE_INSN_CODE
, num_clobbers_to_add
= 0;
10999 /* If we had any clobbers to add, make a new pattern than contains
11000 them. Then check to make sure that all of them are dead. */
11001 if (num_clobbers_to_add
)
11003 rtx newpat
= gen_rtx_PARALLEL (VOIDmode
,
11004 rtvec_alloc (GET_CODE (pat
) == PARALLEL
11005 ? (XVECLEN (pat
, 0)
11006 + num_clobbers_to_add
)
11007 : num_clobbers_to_add
+ 1));
11009 if (GET_CODE (pat
) == PARALLEL
)
11010 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
11011 XVECEXP (newpat
, 0, i
) = XVECEXP (pat
, 0, i
);
11013 XVECEXP (newpat
, 0, 0) = pat
;
11015 add_clobbers (newpat
, insn_code_number
);
11017 for (i
= XVECLEN (newpat
, 0) - num_clobbers_to_add
;
11018 i
< XVECLEN (newpat
, 0); i
++)
11020 if (REG_P (XEXP (XVECEXP (newpat
, 0, i
), 0))
11021 && ! reg_dead_at_p (XEXP (XVECEXP (newpat
, 0, i
), 0), insn
))
11023 if (GET_CODE (XEXP (XVECEXP (newpat
, 0, i
), 0)) != SCRATCH
)
11025 gcc_assert (REG_P (XEXP (XVECEXP (newpat
, 0, i
), 0)));
11026 notes
= alloc_reg_note (REG_UNUSED
,
11027 XEXP (XVECEXP (newpat
, 0, i
), 0), notes
);
11033 if (insn_code_number
>= 0
11034 && insn_code_number
!= NOOP_MOVE_INSN_CODE
)
11036 old_pat
= PATTERN (insn
);
11037 old_notes
= REG_NOTES (insn
);
11038 old_icode
= INSN_CODE (insn
);
11039 PATTERN (insn
) = pat
;
11040 REG_NOTES (insn
) = notes
;
11042 /* Allow targets to reject combined insn. */
11043 if (!targetm
.legitimate_combined_insn (insn
))
11045 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
11046 fputs ("Instruction not appropriate for target.",
11049 /* Callers expect recog_for_combine to strip
11050 clobbers from the pattern on failure. */
11051 pat
= pat_without_clobbers
;
11054 insn_code_number
= -1;
11057 PATTERN (insn
) = old_pat
;
11058 REG_NOTES (insn
) = old_notes
;
11059 INSN_CODE (insn
) = old_icode
;
11065 return insn_code_number
;
11068 /* Change every ZERO_EXTRACT and ZERO_EXTEND of a SUBREG that can be
11069 expressed as an AND and maybe an LSHIFTRT, to that formulation.
11070 Return whether anything was so changed. */
11073 change_zero_ext (rtx
*src
)
11075 bool changed
= false;
11077 subrtx_ptr_iterator::array_type array
;
11078 FOR_EACH_SUBRTX_PTR (iter
, array
, src
, NONCONST
)
11081 machine_mode mode
= GET_MODE (x
);
11084 if (GET_CODE (x
) == ZERO_EXTRACT
11085 && CONST_INT_P (XEXP (x
, 1))
11086 && CONST_INT_P (XEXP (x
, 2))
11087 && GET_MODE (XEXP (x
, 0)) == mode
)
11089 size
= INTVAL (XEXP (x
, 1));
11091 int start
= INTVAL (XEXP (x
, 2));
11092 if (BITS_BIG_ENDIAN
)
11093 start
= GET_MODE_PRECISION (mode
) - size
- start
;
11095 x
= simplify_gen_binary (LSHIFTRT
, mode
,
11096 XEXP (x
, 0), GEN_INT (start
));
11098 else if (GET_CODE (x
) == ZERO_EXTEND
11099 && GET_CODE (XEXP (x
, 0)) == SUBREG
11100 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == mode
11101 && subreg_lowpart_p (XEXP (x
, 0)))
11103 size
= GET_MODE_PRECISION (GET_MODE (XEXP (x
, 0)));
11104 x
= SUBREG_REG (XEXP (x
, 0));
11109 unsigned HOST_WIDE_INT mask
= 1;
11113 x
= gen_rtx_AND (mode
, x
, GEN_INT (mask
));
11122 /* Like recog, but we receive the address of a pointer to a new pattern.
11123 We try to match the rtx that the pointer points to.
11124 If that fails, we may try to modify or replace the pattern,
11125 storing the replacement into the same pointer object.
11127 Modifications include deletion or addition of CLOBBERs. If the
11128 instruction will still not match, we change ZERO_EXTEND and ZERO_EXTRACT
11129 to the equivalent AND and perhaps LSHIFTRT patterns, and try with that
11130 (and undo if that fails).
11132 PNOTES is a pointer to a location where any REG_UNUSED notes added for
11133 the CLOBBERs are placed.
11135 The value is the final insn code from the pattern ultimately matched,
11139 recog_for_combine (rtx
*pnewpat
, rtx_insn
*insn
, rtx
*pnotes
)
11141 rtx pat
= PATTERN (insn
);
11142 int insn_code_number
= recog_for_combine_1 (pnewpat
, insn
, pnotes
);
11143 if (insn_code_number
>= 0 || check_asm_operands (pat
))
11144 return insn_code_number
;
11146 void *marker
= get_undo_marker ();
11147 bool changed
= false;
11149 if (GET_CODE (pat
) == SET
)
11150 changed
= change_zero_ext (&SET_SRC (pat
));
11151 else if (GET_CODE (pat
) == PARALLEL
)
11154 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
11156 rtx set
= XVECEXP (pat
, 0, i
);
11157 if (GET_CODE (set
) == SET
)
11158 changed
|= change_zero_ext (&SET_SRC (set
));
11164 insn_code_number
= recog_for_combine_1 (pnewpat
, insn
, pnotes
);
11166 if (insn_code_number
< 0)
11167 undo_to_marker (marker
);
11170 return insn_code_number
;
11173 /* Like gen_lowpart_general but for use by combine. In combine it
11174 is not possible to create any new pseudoregs. However, it is
11175 safe to create invalid memory addresses, because combine will
11176 try to recognize them and all they will do is make the combine
11179 If for some reason this cannot do its job, an rtx
11180 (clobber (const_int 0)) is returned.
11181 An insn containing that will not be recognized. */
11184 gen_lowpart_for_combine (machine_mode omode
, rtx x
)
11186 machine_mode imode
= GET_MODE (x
);
11187 unsigned int osize
= GET_MODE_SIZE (omode
);
11188 unsigned int isize
= GET_MODE_SIZE (imode
);
11191 if (omode
== imode
)
11194 /* We can only support MODE being wider than a word if X is a
11195 constant integer or has a mode the same size. */
11196 if (GET_MODE_SIZE (omode
) > UNITS_PER_WORD
11197 && ! (CONST_SCALAR_INT_P (x
) || isize
== osize
))
11200 /* X might be a paradoxical (subreg (mem)). In that case, gen_lowpart
11201 won't know what to do. So we will strip off the SUBREG here and
11202 process normally. */
11203 if (GET_CODE (x
) == SUBREG
&& MEM_P (SUBREG_REG (x
)))
11205 x
= SUBREG_REG (x
);
11207 /* For use in case we fall down into the address adjustments
11208 further below, we need to adjust the known mode and size of
11209 x; imode and isize, since we just adjusted x. */
11210 imode
= GET_MODE (x
);
11212 if (imode
== omode
)
11215 isize
= GET_MODE_SIZE (imode
);
11218 result
= gen_lowpart_common (omode
, x
);
11227 /* Refuse to work on a volatile memory ref or one with a mode-dependent
11229 if (MEM_VOLATILE_P (x
)
11230 || mode_dependent_address_p (XEXP (x
, 0), MEM_ADDR_SPACE (x
)))
11233 /* If we want to refer to something bigger than the original memref,
11234 generate a paradoxical subreg instead. That will force a reload
11235 of the original memref X. */
11237 return gen_rtx_SUBREG (omode
, x
, 0);
11239 if (WORDS_BIG_ENDIAN
)
11240 offset
= MAX (isize
, UNITS_PER_WORD
) - MAX (osize
, UNITS_PER_WORD
);
11242 /* Adjust the address so that the address-after-the-data is
11244 if (BYTES_BIG_ENDIAN
)
11245 offset
-= MIN (UNITS_PER_WORD
, osize
) - MIN (UNITS_PER_WORD
, isize
);
11247 return adjust_address_nv (x
, omode
, offset
);
11250 /* If X is a comparison operator, rewrite it in a new mode. This
11251 probably won't match, but may allow further simplifications. */
11252 else if (COMPARISON_P (x
))
11253 return gen_rtx_fmt_ee (GET_CODE (x
), omode
, XEXP (x
, 0), XEXP (x
, 1));
11255 /* If we couldn't simplify X any other way, just enclose it in a
11256 SUBREG. Normally, this SUBREG won't match, but some patterns may
11257 include an explicit SUBREG or we may simplify it further in combine. */
11262 if (imode
== VOIDmode
)
11264 imode
= int_mode_for_mode (omode
);
11265 x
= gen_lowpart_common (imode
, x
);
11269 res
= lowpart_subreg (omode
, x
, imode
);
11275 return gen_rtx_CLOBBER (omode
, const0_rtx
);
11278 /* Try to simplify a comparison between OP0 and a constant OP1,
11279 where CODE is the comparison code that will be tested, into a
11280 (CODE OP0 const0_rtx) form.
11282 The result is a possibly different comparison code to use.
11283 *POP1 may be updated. */
11285 static enum rtx_code
11286 simplify_compare_const (enum rtx_code code
, machine_mode mode
,
11287 rtx op0
, rtx
*pop1
)
11289 unsigned int mode_width
= GET_MODE_PRECISION (mode
);
11290 HOST_WIDE_INT const_op
= INTVAL (*pop1
);
11292 /* Get the constant we are comparing against and turn off all bits
11293 not on in our mode. */
11294 if (mode
!= VOIDmode
)
11295 const_op
= trunc_int_for_mode (const_op
, mode
);
11297 /* If we are comparing against a constant power of two and the value
11298 being compared can only have that single bit nonzero (e.g., it was
11299 `and'ed with that bit), we can replace this with a comparison
11302 && (code
== EQ
|| code
== NE
|| code
== GE
|| code
== GEU
11303 || code
== LT
|| code
== LTU
)
11304 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11305 && exact_log2 (const_op
& GET_MODE_MASK (mode
)) >= 0
11306 && (nonzero_bits (op0
, mode
)
11307 == (unsigned HOST_WIDE_INT
) (const_op
& GET_MODE_MASK (mode
))))
11309 code
= (code
== EQ
|| code
== GE
|| code
== GEU
? NE
: EQ
);
11313 /* Similarly, if we are comparing a value known to be either -1 or
11314 0 with -1, change it to the opposite comparison against zero. */
11316 && (code
== EQ
|| code
== NE
|| code
== GT
|| code
== LE
11317 || code
== GEU
|| code
== LTU
)
11318 && num_sign_bit_copies (op0
, mode
) == mode_width
)
11320 code
= (code
== EQ
|| code
== LE
|| code
== GEU
? NE
: EQ
);
11324 /* Do some canonicalizations based on the comparison code. We prefer
11325 comparisons against zero and then prefer equality comparisons.
11326 If we can reduce the size of a constant, we will do that too. */
11330 /* < C is equivalent to <= (C - 1) */
11335 /* ... fall through to LE case below. */
11341 /* <= C is equivalent to < (C + 1); we do this for C < 0 */
11348 /* If we are doing a <= 0 comparison on a value known to have
11349 a zero sign bit, we can replace this with == 0. */
11350 else if (const_op
== 0
11351 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11352 && (nonzero_bits (op0
, mode
)
11353 & ((unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)))
11359 /* >= C is equivalent to > (C - 1). */
11364 /* ... fall through to GT below. */
11370 /* > C is equivalent to >= (C + 1); we do this for C < 0. */
11377 /* If we are doing a > 0 comparison on a value known to have
11378 a zero sign bit, we can replace this with != 0. */
11379 else if (const_op
== 0
11380 && mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11381 && (nonzero_bits (op0
, mode
)
11382 & ((unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)))
11388 /* < C is equivalent to <= (C - 1). */
11393 /* ... fall through ... */
11395 /* (unsigned) < 0x80000000 is equivalent to >= 0. */
11396 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11397 && (unsigned HOST_WIDE_INT
) const_op
11398 == (unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1))
11408 /* unsigned <= 0 is equivalent to == 0 */
11411 /* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
11412 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11413 && (unsigned HOST_WIDE_INT
) const_op
11414 == ((unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)) - 1)
11422 /* >= C is equivalent to > (C - 1). */
11427 /* ... fall through ... */
11430 /* (unsigned) >= 0x80000000 is equivalent to < 0. */
11431 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11432 && (unsigned HOST_WIDE_INT
) const_op
11433 == (unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1))
11443 /* unsigned > 0 is equivalent to != 0 */
11446 /* (unsigned) > 0x7fffffff is equivalent to < 0. */
11447 else if (mode_width
- 1 < HOST_BITS_PER_WIDE_INT
11448 && (unsigned HOST_WIDE_INT
) const_op
11449 == ((unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)) - 1)
11460 *pop1
= GEN_INT (const_op
);
11464 /* Simplify a comparison between *POP0 and *POP1 where CODE is the
11465 comparison code that will be tested.
11467 The result is a possibly different comparison code to use. *POP0 and
11468 *POP1 may be updated.
11470 It is possible that we might detect that a comparison is either always
11471 true or always false. However, we do not perform general constant
11472 folding in combine, so this knowledge isn't useful. Such tautologies
11473 should have been detected earlier. Hence we ignore all such cases. */
11475 static enum rtx_code
11476 simplify_comparison (enum rtx_code code
, rtx
*pop0
, rtx
*pop1
)
11482 machine_mode mode
, tmode
;
11484 /* Try a few ways of applying the same transformation to both operands. */
11487 /* The test below this one won't handle SIGN_EXTENDs on these machines,
11488 so check specially. */
11489 if (!WORD_REGISTER_OPERATIONS
11490 && code
!= GTU
&& code
!= GEU
&& code
!= LTU
&& code
!= LEU
11491 && GET_CODE (op0
) == ASHIFTRT
&& GET_CODE (op1
) == ASHIFTRT
11492 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
11493 && GET_CODE (XEXP (op1
, 0)) == ASHIFT
11494 && GET_CODE (XEXP (XEXP (op0
, 0), 0)) == SUBREG
11495 && GET_CODE (XEXP (XEXP (op1
, 0), 0)) == SUBREG
11496 && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0)))
11497 == GET_MODE (SUBREG_REG (XEXP (XEXP (op1
, 0), 0))))
11498 && CONST_INT_P (XEXP (op0
, 1))
11499 && XEXP (op0
, 1) == XEXP (op1
, 1)
11500 && XEXP (op0
, 1) == XEXP (XEXP (op0
, 0), 1)
11501 && XEXP (op0
, 1) == XEXP (XEXP (op1
, 0), 1)
11502 && (INTVAL (XEXP (op0
, 1))
11503 == (GET_MODE_PRECISION (GET_MODE (op0
))
11504 - (GET_MODE_PRECISION
11505 (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0))))))))
11507 op0
= SUBREG_REG (XEXP (XEXP (op0
, 0), 0));
11508 op1
= SUBREG_REG (XEXP (XEXP (op1
, 0), 0));
11511 /* If both operands are the same constant shift, see if we can ignore the
11512 shift. We can if the shift is a rotate or if the bits shifted out of
11513 this shift are known to be zero for both inputs and if the type of
11514 comparison is compatible with the shift. */
11515 if (GET_CODE (op0
) == GET_CODE (op1
)
11516 && HWI_COMPUTABLE_MODE_P (GET_MODE (op0
))
11517 && ((GET_CODE (op0
) == ROTATE
&& (code
== NE
|| code
== EQ
))
11518 || ((GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFT
)
11519 && (code
!= GT
&& code
!= LT
&& code
!= GE
&& code
!= LE
))
11520 || (GET_CODE (op0
) == ASHIFTRT
11521 && (code
!= GTU
&& code
!= LTU
11522 && code
!= GEU
&& code
!= LEU
)))
11523 && CONST_INT_P (XEXP (op0
, 1))
11524 && INTVAL (XEXP (op0
, 1)) >= 0
11525 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
11526 && XEXP (op0
, 1) == XEXP (op1
, 1))
11528 machine_mode mode
= GET_MODE (op0
);
11529 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
11530 int shift_count
= INTVAL (XEXP (op0
, 1));
11532 if (GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFTRT
)
11533 mask
&= (mask
>> shift_count
) << shift_count
;
11534 else if (GET_CODE (op0
) == ASHIFT
)
11535 mask
= (mask
& (mask
<< shift_count
)) >> shift_count
;
11537 if ((nonzero_bits (XEXP (op0
, 0), mode
) & ~mask
) == 0
11538 && (nonzero_bits (XEXP (op1
, 0), mode
) & ~mask
) == 0)
11539 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0);
11544 /* If both operands are AND's of a paradoxical SUBREG by constant, the
11545 SUBREGs are of the same mode, and, in both cases, the AND would
11546 be redundant if the comparison was done in the narrower mode,
11547 do the comparison in the narrower mode (e.g., we are AND'ing with 1
11548 and the operand's possibly nonzero bits are 0xffffff01; in that case
11549 if we only care about QImode, we don't need the AND). This case
11550 occurs if the output mode of an scc insn is not SImode and
11551 STORE_FLAG_VALUE == 1 (e.g., the 386).
11553 Similarly, check for a case where the AND's are ZERO_EXTEND
11554 operations from some narrower mode even though a SUBREG is not
11557 else if (GET_CODE (op0
) == AND
&& GET_CODE (op1
) == AND
11558 && CONST_INT_P (XEXP (op0
, 1))
11559 && CONST_INT_P (XEXP (op1
, 1)))
11561 rtx inner_op0
= XEXP (op0
, 0);
11562 rtx inner_op1
= XEXP (op1
, 0);
11563 HOST_WIDE_INT c0
= INTVAL (XEXP (op0
, 1));
11564 HOST_WIDE_INT c1
= INTVAL (XEXP (op1
, 1));
11567 if (paradoxical_subreg_p (inner_op0
)
11568 && GET_CODE (inner_op1
) == SUBREG
11569 && (GET_MODE (SUBREG_REG (inner_op0
))
11570 == GET_MODE (SUBREG_REG (inner_op1
)))
11571 && (GET_MODE_PRECISION (GET_MODE (SUBREG_REG (inner_op0
)))
11572 <= HOST_BITS_PER_WIDE_INT
)
11573 && (0 == ((~c0
) & nonzero_bits (SUBREG_REG (inner_op0
),
11574 GET_MODE (SUBREG_REG (inner_op0
)))))
11575 && (0 == ((~c1
) & nonzero_bits (SUBREG_REG (inner_op1
),
11576 GET_MODE (SUBREG_REG (inner_op1
))))))
11578 op0
= SUBREG_REG (inner_op0
);
11579 op1
= SUBREG_REG (inner_op1
);
11581 /* The resulting comparison is always unsigned since we masked
11582 off the original sign bit. */
11583 code
= unsigned_condition (code
);
11589 for (tmode
= GET_CLASS_NARROWEST_MODE
11590 (GET_MODE_CLASS (GET_MODE (op0
)));
11591 tmode
!= GET_MODE (op0
); tmode
= GET_MODE_WIDER_MODE (tmode
))
11592 if ((unsigned HOST_WIDE_INT
) c0
== GET_MODE_MASK (tmode
))
11594 op0
= gen_lowpart_or_truncate (tmode
, inner_op0
);
11595 op1
= gen_lowpart_or_truncate (tmode
, inner_op1
);
11596 code
= unsigned_condition (code
);
11605 /* If both operands are NOT, we can strip off the outer operation
11606 and adjust the comparison code for swapped operands; similarly for
11607 NEG, except that this must be an equality comparison. */
11608 else if ((GET_CODE (op0
) == NOT
&& GET_CODE (op1
) == NOT
)
11609 || (GET_CODE (op0
) == NEG
&& GET_CODE (op1
) == NEG
11610 && (code
== EQ
|| code
== NE
)))
11611 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0), code
= swap_condition (code
);
11617 /* If the first operand is a constant, swap the operands and adjust the
11618 comparison code appropriately, but don't do this if the second operand
11619 is already a constant integer. */
11620 if (swap_commutative_operands_p (op0
, op1
))
11622 std::swap (op0
, op1
);
11623 code
= swap_condition (code
);
11626 /* We now enter a loop during which we will try to simplify the comparison.
11627 For the most part, we only are concerned with comparisons with zero,
11628 but some things may really be comparisons with zero but not start
11629 out looking that way. */
11631 while (CONST_INT_P (op1
))
11633 machine_mode mode
= GET_MODE (op0
);
11634 unsigned int mode_width
= GET_MODE_PRECISION (mode
);
11635 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
11636 int equality_comparison_p
;
11637 int sign_bit_comparison_p
;
11638 int unsigned_comparison_p
;
11639 HOST_WIDE_INT const_op
;
11641 /* We only want to handle integral modes. This catches VOIDmode,
11642 CCmode, and the floating-point modes. An exception is that we
11643 can handle VOIDmode if OP0 is a COMPARE or a comparison
11646 if (GET_MODE_CLASS (mode
) != MODE_INT
11647 && ! (mode
== VOIDmode
11648 && (GET_CODE (op0
) == COMPARE
|| COMPARISON_P (op0
))))
11651 /* Try to simplify the compare to constant, possibly changing the
11652 comparison op, and/or changing op1 to zero. */
11653 code
= simplify_compare_const (code
, mode
, op0
, &op1
);
11654 const_op
= INTVAL (op1
);
11656 /* Compute some predicates to simplify code below. */
11658 equality_comparison_p
= (code
== EQ
|| code
== NE
);
11659 sign_bit_comparison_p
= ((code
== LT
|| code
== GE
) && const_op
== 0);
11660 unsigned_comparison_p
= (code
== LTU
|| code
== LEU
|| code
== GTU
11663 /* If this is a sign bit comparison and we can do arithmetic in
11664 MODE, say that we will only be needing the sign bit of OP0. */
11665 if (sign_bit_comparison_p
&& HWI_COMPUTABLE_MODE_P (mode
))
11666 op0
= force_to_mode (op0
, mode
,
11667 (unsigned HOST_WIDE_INT
) 1
11668 << (GET_MODE_PRECISION (mode
) - 1),
11671 /* Now try cases based on the opcode of OP0. If none of the cases
11672 does a "continue", we exit this loop immediately after the
11675 switch (GET_CODE (op0
))
11678 /* If we are extracting a single bit from a variable position in
11679 a constant that has only a single bit set and are comparing it
11680 with zero, we can convert this into an equality comparison
11681 between the position and the location of the single bit. */
11682 /* Except we can't if SHIFT_COUNT_TRUNCATED is set, since we might
11683 have already reduced the shift count modulo the word size. */
11684 if (!SHIFT_COUNT_TRUNCATED
11685 && CONST_INT_P (XEXP (op0
, 0))
11686 && XEXP (op0
, 1) == const1_rtx
11687 && equality_comparison_p
&& const_op
== 0
11688 && (i
= exact_log2 (UINTVAL (XEXP (op0
, 0)))) >= 0)
11690 if (BITS_BIG_ENDIAN
)
11691 i
= BITS_PER_WORD
- 1 - i
;
11693 op0
= XEXP (op0
, 2);
11697 /* Result is nonzero iff shift count is equal to I. */
11698 code
= reverse_condition (code
);
11702 /* ... fall through ... */
11705 tem
= expand_compound_operation (op0
);
11714 /* If testing for equality, we can take the NOT of the constant. */
11715 if (equality_comparison_p
11716 && (tem
= simplify_unary_operation (NOT
, mode
, op1
, mode
)) != 0)
11718 op0
= XEXP (op0
, 0);
11723 /* If just looking at the sign bit, reverse the sense of the
11725 if (sign_bit_comparison_p
)
11727 op0
= XEXP (op0
, 0);
11728 code
= (code
== GE
? LT
: GE
);
11734 /* If testing for equality, we can take the NEG of the constant. */
11735 if (equality_comparison_p
11736 && (tem
= simplify_unary_operation (NEG
, mode
, op1
, mode
)) != 0)
11738 op0
= XEXP (op0
, 0);
11743 /* The remaining cases only apply to comparisons with zero. */
11747 /* When X is ABS or is known positive,
11748 (neg X) is < 0 if and only if X != 0. */
11750 if (sign_bit_comparison_p
11751 && (GET_CODE (XEXP (op0
, 0)) == ABS
11752 || (mode_width
<= HOST_BITS_PER_WIDE_INT
11753 && (nonzero_bits (XEXP (op0
, 0), mode
)
11754 & ((unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)))
11757 op0
= XEXP (op0
, 0);
11758 code
= (code
== LT
? NE
: EQ
);
11762 /* If we have NEG of something whose two high-order bits are the
11763 same, we know that "(-a) < 0" is equivalent to "a > 0". */
11764 if (num_sign_bit_copies (op0
, mode
) >= 2)
11766 op0
= XEXP (op0
, 0);
11767 code
= swap_condition (code
);
11773 /* If we are testing equality and our count is a constant, we
11774 can perform the inverse operation on our RHS. */
11775 if (equality_comparison_p
&& CONST_INT_P (XEXP (op0
, 1))
11776 && (tem
= simplify_binary_operation (ROTATERT
, mode
,
11777 op1
, XEXP (op0
, 1))) != 0)
11779 op0
= XEXP (op0
, 0);
11784 /* If we are doing a < 0 or >= 0 comparison, it means we are testing
11785 a particular bit. Convert it to an AND of a constant of that
11786 bit. This will be converted into a ZERO_EXTRACT. */
11787 if (const_op
== 0 && sign_bit_comparison_p
11788 && CONST_INT_P (XEXP (op0
, 1))
11789 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
11791 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
11792 ((unsigned HOST_WIDE_INT
) 1
11794 - INTVAL (XEXP (op0
, 1)))));
11795 code
= (code
== LT
? NE
: EQ
);
11799 /* Fall through. */
11802 /* ABS is ignorable inside an equality comparison with zero. */
11803 if (const_op
== 0 && equality_comparison_p
)
11805 op0
= XEXP (op0
, 0);
11811 /* Can simplify (compare (zero/sign_extend FOO) CONST) to
11812 (compare FOO CONST) if CONST fits in FOO's mode and we
11813 are either testing inequality or have an unsigned
11814 comparison with ZERO_EXTEND or a signed comparison with
11815 SIGN_EXTEND. But don't do it if we don't have a compare
11816 insn of the given mode, since we'd have to revert it
11817 later on, and then we wouldn't know whether to sign- or
11819 mode
= GET_MODE (XEXP (op0
, 0));
11820 if (GET_MODE_CLASS (mode
) == MODE_INT
11821 && ! unsigned_comparison_p
11822 && HWI_COMPUTABLE_MODE_P (mode
)
11823 && trunc_int_for_mode (const_op
, mode
) == const_op
11824 && have_insn_for (COMPARE
, mode
))
11826 op0
= XEXP (op0
, 0);
11832 /* Check for the case where we are comparing A - C1 with C2, that is
11834 (subreg:MODE (plus (A) (-C1))) op (C2)
11836 with C1 a constant, and try to lift the SUBREG, i.e. to do the
11837 comparison in the wider mode. One of the following two conditions
11838 must be true in order for this to be valid:
11840 1. The mode extension results in the same bit pattern being added
11841 on both sides and the comparison is equality or unsigned. As
11842 C2 has been truncated to fit in MODE, the pattern can only be
11845 2. The mode extension results in the sign bit being copied on
11848 The difficulty here is that we have predicates for A but not for
11849 (A - C1) so we need to check that C1 is within proper bounds so
11850 as to perturbate A as little as possible. */
11852 if (mode_width
<= HOST_BITS_PER_WIDE_INT
11853 && subreg_lowpart_p (op0
)
11854 && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
))) > mode_width
11855 && GET_CODE (SUBREG_REG (op0
)) == PLUS
11856 && CONST_INT_P (XEXP (SUBREG_REG (op0
), 1)))
11858 machine_mode inner_mode
= GET_MODE (SUBREG_REG (op0
));
11859 rtx a
= XEXP (SUBREG_REG (op0
), 0);
11860 HOST_WIDE_INT c1
= -INTVAL (XEXP (SUBREG_REG (op0
), 1));
11863 && (unsigned HOST_WIDE_INT
) c1
11864 < (unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)
11865 && (equality_comparison_p
|| unsigned_comparison_p
)
11866 /* (A - C1) zero-extends if it is positive and sign-extends
11867 if it is negative, C2 both zero- and sign-extends. */
11868 && ((0 == (nonzero_bits (a
, inner_mode
)
11869 & ~GET_MODE_MASK (mode
))
11871 /* (A - C1) sign-extends if it is positive and 1-extends
11872 if it is negative, C2 both sign- and 1-extends. */
11873 || (num_sign_bit_copies (a
, inner_mode
)
11874 > (unsigned int) (GET_MODE_PRECISION (inner_mode
)
11877 || ((unsigned HOST_WIDE_INT
) c1
11878 < (unsigned HOST_WIDE_INT
) 1 << (mode_width
- 2)
11879 /* (A - C1) always sign-extends, like C2. */
11880 && num_sign_bit_copies (a
, inner_mode
)
11881 > (unsigned int) (GET_MODE_PRECISION (inner_mode
)
11882 - (mode_width
- 1))))
11884 op0
= SUBREG_REG (op0
);
11889 /* If the inner mode is narrower and we are extracting the low part,
11890 we can treat the SUBREG as if it were a ZERO_EXTEND. */
11891 if (subreg_lowpart_p (op0
)
11892 && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
))) < mode_width
)
11893 /* Fall through */ ;
11897 /* ... fall through ... */
11900 mode
= GET_MODE (XEXP (op0
, 0));
11901 if (GET_MODE_CLASS (mode
) == MODE_INT
11902 && (unsigned_comparison_p
|| equality_comparison_p
)
11903 && HWI_COMPUTABLE_MODE_P (mode
)
11904 && (unsigned HOST_WIDE_INT
) const_op
<= GET_MODE_MASK (mode
)
11906 && have_insn_for (COMPARE
, mode
))
11908 op0
= XEXP (op0
, 0);
11914 /* (eq (plus X A) B) -> (eq X (minus B A)). We can only do
11915 this for equality comparisons due to pathological cases involving
11917 if (equality_comparison_p
11918 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
11919 op1
, XEXP (op0
, 1))))
11921 op0
= XEXP (op0
, 0);
11926 /* (plus (abs X) (const_int -1)) is < 0 if and only if X == 0. */
11927 if (const_op
== 0 && XEXP (op0
, 1) == constm1_rtx
11928 && GET_CODE (XEXP (op0
, 0)) == ABS
&& sign_bit_comparison_p
)
11930 op0
= XEXP (XEXP (op0
, 0), 0);
11931 code
= (code
== LT
? EQ
: NE
);
11937 /* We used to optimize signed comparisons against zero, but that
11938 was incorrect. Unsigned comparisons against zero (GTU, LEU)
11939 arrive here as equality comparisons, or (GEU, LTU) are
11940 optimized away. No need to special-case them. */
11942 /* (eq (minus A B) C) -> (eq A (plus B C)) or
11943 (eq B (minus A C)), whichever simplifies. We can only do
11944 this for equality comparisons due to pathological cases involving
11946 if (equality_comparison_p
11947 && 0 != (tem
= simplify_binary_operation (PLUS
, mode
,
11948 XEXP (op0
, 1), op1
)))
11950 op0
= XEXP (op0
, 0);
11955 if (equality_comparison_p
11956 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
11957 XEXP (op0
, 0), op1
)))
11959 op0
= XEXP (op0
, 1);
11964 /* The sign bit of (minus (ashiftrt X C) X), where C is the number
11965 of bits in X minus 1, is one iff X > 0. */
11966 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == ASHIFTRT
11967 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
11968 && UINTVAL (XEXP (XEXP (op0
, 0), 1)) == mode_width
- 1
11969 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
11971 op0
= XEXP (op0
, 1);
11972 code
= (code
== GE
? LE
: GT
);
11978 /* (eq (xor A B) C) -> (eq A (xor B C)). This is a simplification
11979 if C is zero or B is a constant. */
11980 if (equality_comparison_p
11981 && 0 != (tem
= simplify_binary_operation (XOR
, mode
,
11982 XEXP (op0
, 1), op1
)))
11984 op0
= XEXP (op0
, 0);
11991 case UNEQ
: case LTGT
:
11992 case LT
: case LTU
: case UNLT
: case LE
: case LEU
: case UNLE
:
11993 case GT
: case GTU
: case UNGT
: case GE
: case GEU
: case UNGE
:
11994 case UNORDERED
: case ORDERED
:
11995 /* We can't do anything if OP0 is a condition code value, rather
11996 than an actual data value. */
11998 || CC0_P (XEXP (op0
, 0))
11999 || GET_MODE_CLASS (GET_MODE (XEXP (op0
, 0))) == MODE_CC
)
12002 /* Get the two operands being compared. */
12003 if (GET_CODE (XEXP (op0
, 0)) == COMPARE
)
12004 tem
= XEXP (XEXP (op0
, 0), 0), tem1
= XEXP (XEXP (op0
, 0), 1);
12006 tem
= XEXP (op0
, 0), tem1
= XEXP (op0
, 1);
12008 /* Check for the cases where we simply want the result of the
12009 earlier test or the opposite of that result. */
12010 if (code
== NE
|| code
== EQ
12011 || (val_signbit_known_set_p (GET_MODE (op0
), STORE_FLAG_VALUE
)
12012 && (code
== LT
|| code
== GE
)))
12014 enum rtx_code new_code
;
12015 if (code
== LT
|| code
== NE
)
12016 new_code
= GET_CODE (op0
);
12018 new_code
= reversed_comparison_code (op0
, NULL
);
12020 if (new_code
!= UNKNOWN
)
12031 /* The sign bit of (ior (plus X (const_int -1)) X) is nonzero
12033 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == PLUS
12034 && XEXP (XEXP (op0
, 0), 1) == constm1_rtx
12035 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
12037 op0
= XEXP (op0
, 1);
12038 code
= (code
== GE
? GT
: LE
);
12044 /* Convert (and (xshift 1 X) Y) to (and (lshiftrt Y X) 1). This
12045 will be converted to a ZERO_EXTRACT later. */
12046 if (const_op
== 0 && equality_comparison_p
12047 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
12048 && XEXP (XEXP (op0
, 0), 0) == const1_rtx
)
12050 op0
= gen_rtx_LSHIFTRT (mode
, XEXP (op0
, 1),
12051 XEXP (XEXP (op0
, 0), 1));
12052 op0
= simplify_and_const_int (NULL_RTX
, mode
, op0
, 1);
12056 /* If we are comparing (and (lshiftrt X C1) C2) for equality with
12057 zero and X is a comparison and C1 and C2 describe only bits set
12058 in STORE_FLAG_VALUE, we can compare with X. */
12059 if (const_op
== 0 && equality_comparison_p
12060 && mode_width
<= HOST_BITS_PER_WIDE_INT
12061 && CONST_INT_P (XEXP (op0
, 1))
12062 && GET_CODE (XEXP (op0
, 0)) == LSHIFTRT
12063 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
12064 && INTVAL (XEXP (XEXP (op0
, 0), 1)) >= 0
12065 && INTVAL (XEXP (XEXP (op0
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
12067 mask
= ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
12068 << INTVAL (XEXP (XEXP (op0
, 0), 1)));
12069 if ((~STORE_FLAG_VALUE
& mask
) == 0
12070 && (COMPARISON_P (XEXP (XEXP (op0
, 0), 0))
12071 || ((tem
= get_last_value (XEXP (XEXP (op0
, 0), 0))) != 0
12072 && COMPARISON_P (tem
))))
12074 op0
= XEXP (XEXP (op0
, 0), 0);
12079 /* If we are doing an equality comparison of an AND of a bit equal
12080 to the sign bit, replace this with a LT or GE comparison of
12081 the underlying value. */
12082 if (equality_comparison_p
12084 && CONST_INT_P (XEXP (op0
, 1))
12085 && mode_width
<= HOST_BITS_PER_WIDE_INT
12086 && ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
12087 == (unsigned HOST_WIDE_INT
) 1 << (mode_width
- 1)))
12089 op0
= XEXP (op0
, 0);
12090 code
= (code
== EQ
? GE
: LT
);
12094 /* If this AND operation is really a ZERO_EXTEND from a narrower
12095 mode, the constant fits within that mode, and this is either an
12096 equality or unsigned comparison, try to do this comparison in
12101 (ne:DI (and:DI (reg:DI 4) (const_int 0xffffffff)) (const_int 0))
12102 -> (ne:DI (reg:SI 4) (const_int 0))
12104 unless TRULY_NOOP_TRUNCATION allows it or the register is
12105 known to hold a value of the required mode the
12106 transformation is invalid. */
12107 if ((equality_comparison_p
|| unsigned_comparison_p
)
12108 && CONST_INT_P (XEXP (op0
, 1))
12109 && (i
= exact_log2 ((UINTVAL (XEXP (op0
, 1))
12110 & GET_MODE_MASK (mode
))
12112 && const_op
>> i
== 0
12113 && (tmode
= mode_for_size (i
, MODE_INT
, 1)) != BLKmode
)
12115 op0
= gen_lowpart_or_truncate (tmode
, XEXP (op0
, 0));
12119 /* If this is (and:M1 (subreg:M1 X:M2 0) (const_int C1)) where C1
12120 fits in both M1 and M2 and the SUBREG is either paradoxical
12121 or represents the low part, permute the SUBREG and the AND
12123 if (GET_CODE (XEXP (op0
, 0)) == SUBREG
12124 && CONST_INT_P (XEXP (op0
, 1)))
12126 tmode
= GET_MODE (SUBREG_REG (XEXP (op0
, 0)));
12127 unsigned HOST_WIDE_INT c1
= INTVAL (XEXP (op0
, 1));
12128 /* Require an integral mode, to avoid creating something like
12130 if (SCALAR_INT_MODE_P (tmode
)
12131 /* It is unsafe to commute the AND into the SUBREG if the
12132 SUBREG is paradoxical and WORD_REGISTER_OPERATIONS is
12133 not defined. As originally written the upper bits
12134 have a defined value due to the AND operation.
12135 However, if we commute the AND inside the SUBREG then
12136 they no longer have defined values and the meaning of
12137 the code has been changed.
12138 Also C1 should not change value in the smaller mode,
12139 see PR67028 (a positive C1 can become negative in the
12140 smaller mode, so that the AND does no longer mask the
12142 && ((WORD_REGISTER_OPERATIONS
12143 && mode_width
> GET_MODE_PRECISION (tmode
)
12144 && mode_width
<= BITS_PER_WORD
12145 && trunc_int_for_mode (c1
, tmode
) == (HOST_WIDE_INT
) c1
)
12146 || (mode_width
<= GET_MODE_PRECISION (tmode
)
12147 && subreg_lowpart_p (XEXP (op0
, 0))))
12148 && mode_width
<= HOST_BITS_PER_WIDE_INT
12149 && HWI_COMPUTABLE_MODE_P (tmode
)
12150 && (c1
& ~mask
) == 0
12151 && (c1
& ~GET_MODE_MASK (tmode
)) == 0
12153 && c1
!= GET_MODE_MASK (tmode
))
12155 op0
= simplify_gen_binary (AND
, tmode
,
12156 SUBREG_REG (XEXP (op0
, 0)),
12157 gen_int_mode (c1
, tmode
));
12158 op0
= gen_lowpart (mode
, op0
);
12163 /* Convert (ne (and (not X) 1) 0) to (eq (and X 1) 0). */
12164 if (const_op
== 0 && equality_comparison_p
12165 && XEXP (op0
, 1) == const1_rtx
12166 && GET_CODE (XEXP (op0
, 0)) == NOT
)
12168 op0
= simplify_and_const_int (NULL_RTX
, mode
,
12169 XEXP (XEXP (op0
, 0), 0), 1);
12170 code
= (code
== NE
? EQ
: NE
);
12174 /* Convert (ne (and (lshiftrt (not X)) 1) 0) to
12175 (eq (and (lshiftrt X) 1) 0).
12176 Also handle the case where (not X) is expressed using xor. */
12177 if (const_op
== 0 && equality_comparison_p
12178 && XEXP (op0
, 1) == const1_rtx
12179 && GET_CODE (XEXP (op0
, 0)) == LSHIFTRT
)
12181 rtx shift_op
= XEXP (XEXP (op0
, 0), 0);
12182 rtx shift_count
= XEXP (XEXP (op0
, 0), 1);
12184 if (GET_CODE (shift_op
) == NOT
12185 || (GET_CODE (shift_op
) == XOR
12186 && CONST_INT_P (XEXP (shift_op
, 1))
12187 && CONST_INT_P (shift_count
)
12188 && HWI_COMPUTABLE_MODE_P (mode
)
12189 && (UINTVAL (XEXP (shift_op
, 1))
12190 == (unsigned HOST_WIDE_INT
) 1
12191 << INTVAL (shift_count
))))
12194 = gen_rtx_LSHIFTRT (mode
, XEXP (shift_op
, 0), shift_count
);
12195 op0
= simplify_and_const_int (NULL_RTX
, mode
, op0
, 1);
12196 code
= (code
== NE
? EQ
: NE
);
12203 /* If we have (compare (ashift FOO N) (const_int C)) and
12204 the high order N bits of FOO (N+1 if an inequality comparison)
12205 are known to be zero, we can do this by comparing FOO with C
12206 shifted right N bits so long as the low-order N bits of C are
12208 if (CONST_INT_P (XEXP (op0
, 1))
12209 && INTVAL (XEXP (op0
, 1)) >= 0
12210 && ((INTVAL (XEXP (op0
, 1)) + ! equality_comparison_p
)
12211 < HOST_BITS_PER_WIDE_INT
)
12212 && (((unsigned HOST_WIDE_INT
) const_op
12213 & (((unsigned HOST_WIDE_INT
) 1 << INTVAL (XEXP (op0
, 1)))
12215 && mode_width
<= HOST_BITS_PER_WIDE_INT
12216 && (nonzero_bits (XEXP (op0
, 0), mode
)
12217 & ~(mask
>> (INTVAL (XEXP (op0
, 1))
12218 + ! equality_comparison_p
))) == 0)
12220 /* We must perform a logical shift, not an arithmetic one,
12221 as we want the top N bits of C to be zero. */
12222 unsigned HOST_WIDE_INT temp
= const_op
& GET_MODE_MASK (mode
);
12224 temp
>>= INTVAL (XEXP (op0
, 1));
12225 op1
= gen_int_mode (temp
, mode
);
12226 op0
= XEXP (op0
, 0);
12230 /* If we are doing a sign bit comparison, it means we are testing
12231 a particular bit. Convert it to the appropriate AND. */
12232 if (sign_bit_comparison_p
&& CONST_INT_P (XEXP (op0
, 1))
12233 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
12235 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
12236 ((unsigned HOST_WIDE_INT
) 1
12238 - INTVAL (XEXP (op0
, 1)))));
12239 code
= (code
== LT
? NE
: EQ
);
12243 /* If this an equality comparison with zero and we are shifting
12244 the low bit to the sign bit, we can convert this to an AND of the
12246 if (const_op
== 0 && equality_comparison_p
12247 && CONST_INT_P (XEXP (op0
, 1))
12248 && UINTVAL (XEXP (op0
, 1)) == mode_width
- 1)
12250 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0), 1);
12256 /* If this is an equality comparison with zero, we can do this
12257 as a logical shift, which might be much simpler. */
12258 if (equality_comparison_p
&& const_op
== 0
12259 && CONST_INT_P (XEXP (op0
, 1)))
12261 op0
= simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
,
12263 INTVAL (XEXP (op0
, 1)));
12267 /* If OP0 is a sign extension and CODE is not an unsigned comparison,
12268 do the comparison in a narrower mode. */
12269 if (! unsigned_comparison_p
12270 && CONST_INT_P (XEXP (op0
, 1))
12271 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
12272 && XEXP (op0
, 1) == XEXP (XEXP (op0
, 0), 1)
12273 && (tmode
= mode_for_size (mode_width
- INTVAL (XEXP (op0
, 1)),
12274 MODE_INT
, 1)) != BLKmode
12275 && (((unsigned HOST_WIDE_INT
) const_op
12276 + (GET_MODE_MASK (tmode
) >> 1) + 1)
12277 <= GET_MODE_MASK (tmode
)))
12279 op0
= gen_lowpart (tmode
, XEXP (XEXP (op0
, 0), 0));
12283 /* Likewise if OP0 is a PLUS of a sign extension with a
12284 constant, which is usually represented with the PLUS
12285 between the shifts. */
12286 if (! unsigned_comparison_p
12287 && CONST_INT_P (XEXP (op0
, 1))
12288 && GET_CODE (XEXP (op0
, 0)) == PLUS
12289 && CONST_INT_P (XEXP (XEXP (op0
, 0), 1))
12290 && GET_CODE (XEXP (XEXP (op0
, 0), 0)) == ASHIFT
12291 && XEXP (op0
, 1) == XEXP (XEXP (XEXP (op0
, 0), 0), 1)
12292 && (tmode
= mode_for_size (mode_width
- INTVAL (XEXP (op0
, 1)),
12293 MODE_INT
, 1)) != BLKmode
12294 && (((unsigned HOST_WIDE_INT
) const_op
12295 + (GET_MODE_MASK (tmode
) >> 1) + 1)
12296 <= GET_MODE_MASK (tmode
)))
12298 rtx inner
= XEXP (XEXP (XEXP (op0
, 0), 0), 0);
12299 rtx add_const
= XEXP (XEXP (op0
, 0), 1);
12300 rtx new_const
= simplify_gen_binary (ASHIFTRT
, GET_MODE (op0
),
12301 add_const
, XEXP (op0
, 1));
12303 op0
= simplify_gen_binary (PLUS
, tmode
,
12304 gen_lowpart (tmode
, inner
),
12309 /* ... fall through ... */
12311 /* If we have (compare (xshiftrt FOO N) (const_int C)) and
12312 the low order N bits of FOO are known to be zero, we can do this
12313 by comparing FOO with C shifted left N bits so long as no
12314 overflow occurs. Even if the low order N bits of FOO aren't known
12315 to be zero, if the comparison is >= or < we can use the same
12316 optimization and for > or <= by setting all the low
12317 order N bits in the comparison constant. */
12318 if (CONST_INT_P (XEXP (op0
, 1))
12319 && INTVAL (XEXP (op0
, 1)) > 0
12320 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
12321 && mode_width
<= HOST_BITS_PER_WIDE_INT
12322 && (((unsigned HOST_WIDE_INT
) const_op
12323 + (GET_CODE (op0
) != LSHIFTRT
12324 ? ((GET_MODE_MASK (mode
) >> INTVAL (XEXP (op0
, 1)) >> 1)
12327 <= GET_MODE_MASK (mode
) >> INTVAL (XEXP (op0
, 1))))
12329 unsigned HOST_WIDE_INT low_bits
12330 = (nonzero_bits (XEXP (op0
, 0), mode
)
12331 & (((unsigned HOST_WIDE_INT
) 1
12332 << INTVAL (XEXP (op0
, 1))) - 1));
12333 if (low_bits
== 0 || !equality_comparison_p
)
12335 /* If the shift was logical, then we must make the condition
12337 if (GET_CODE (op0
) == LSHIFTRT
)
12338 code
= unsigned_condition (code
);
12340 const_op
<<= INTVAL (XEXP (op0
, 1));
12342 && (code
== GT
|| code
== GTU
12343 || code
== LE
|| code
== LEU
))
12345 |= (((HOST_WIDE_INT
) 1 << INTVAL (XEXP (op0
, 1))) - 1);
12346 op1
= GEN_INT (const_op
);
12347 op0
= XEXP (op0
, 0);
12352 /* If we are using this shift to extract just the sign bit, we
12353 can replace this with an LT or GE comparison. */
12355 && (equality_comparison_p
|| sign_bit_comparison_p
)
12356 && CONST_INT_P (XEXP (op0
, 1))
12357 && UINTVAL (XEXP (op0
, 1)) == mode_width
- 1)
12359 op0
= XEXP (op0
, 0);
12360 code
= (code
== NE
|| code
== GT
? LT
: GE
);
12372 /* Now make any compound operations involved in this comparison. Then,
12373 check for an outmost SUBREG on OP0 that is not doing anything or is
12374 paradoxical. The latter transformation must only be performed when
12375 it is known that the "extra" bits will be the same in op0 and op1 or
12376 that they don't matter. There are three cases to consider:
12378 1. SUBREG_REG (op0) is a register. In this case the bits are don't
12379 care bits and we can assume they have any convenient value. So
12380 making the transformation is safe.
12382 2. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is not defined.
12383 In this case the upper bits of op0 are undefined. We should not make
12384 the simplification in that case as we do not know the contents of
12387 3. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is defined and not
12388 UNKNOWN. In that case we know those bits are zeros or ones. We must
12389 also be sure that they are the same as the upper bits of op1.
12391 We can never remove a SUBREG for a non-equality comparison because
12392 the sign bit is in a different place in the underlying object. */
12394 op0
= make_compound_operation (op0
, op1
== const0_rtx
? COMPARE
: SET
);
12395 op1
= make_compound_operation (op1
, SET
);
12397 if (GET_CODE (op0
) == SUBREG
&& subreg_lowpart_p (op0
)
12398 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
12399 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (op0
))) == MODE_INT
12400 && (code
== NE
|| code
== EQ
))
12402 if (paradoxical_subreg_p (op0
))
12404 /* For paradoxical subregs, allow case 1 as above. Case 3 isn't
12406 if (REG_P (SUBREG_REG (op0
)))
12408 op0
= SUBREG_REG (op0
);
12409 op1
= gen_lowpart (GET_MODE (op0
), op1
);
12412 else if ((GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0
)))
12413 <= HOST_BITS_PER_WIDE_INT
)
12414 && (nonzero_bits (SUBREG_REG (op0
),
12415 GET_MODE (SUBREG_REG (op0
)))
12416 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12418 tem
= gen_lowpart (GET_MODE (SUBREG_REG (op0
)), op1
);
12420 if ((nonzero_bits (tem
, GET_MODE (SUBREG_REG (op0
)))
12421 & ~GET_MODE_MASK (GET_MODE (op0
))) == 0)
12422 op0
= SUBREG_REG (op0
), op1
= tem
;
12426 /* We now do the opposite procedure: Some machines don't have compare
12427 insns in all modes. If OP0's mode is an integer mode smaller than a
12428 word and we can't do a compare in that mode, see if there is a larger
12429 mode for which we can do the compare. There are a number of cases in
12430 which we can use the wider mode. */
12432 mode
= GET_MODE (op0
);
12433 if (mode
!= VOIDmode
&& GET_MODE_CLASS (mode
) == MODE_INT
12434 && GET_MODE_SIZE (mode
) < UNITS_PER_WORD
12435 && ! have_insn_for (COMPARE
, mode
))
12436 for (tmode
= GET_MODE_WIDER_MODE (mode
);
12437 (tmode
!= VOIDmode
&& HWI_COMPUTABLE_MODE_P (tmode
));
12438 tmode
= GET_MODE_WIDER_MODE (tmode
))
12439 if (have_insn_for (COMPARE
, tmode
))
12443 /* If this is a test for negative, we can make an explicit
12444 test of the sign bit. Test this first so we can use
12445 a paradoxical subreg to extend OP0. */
12447 if (op1
== const0_rtx
&& (code
== LT
|| code
== GE
)
12448 && HWI_COMPUTABLE_MODE_P (mode
))
12450 unsigned HOST_WIDE_INT sign
12451 = (unsigned HOST_WIDE_INT
) 1 << (GET_MODE_BITSIZE (mode
) - 1);
12452 op0
= simplify_gen_binary (AND
, tmode
,
12453 gen_lowpart (tmode
, op0
),
12454 gen_int_mode (sign
, tmode
));
12455 code
= (code
== LT
) ? NE
: EQ
;
12459 /* If the only nonzero bits in OP0 and OP1 are those in the
12460 narrower mode and this is an equality or unsigned comparison,
12461 we can use the wider mode. Similarly for sign-extended
12462 values, in which case it is true for all comparisons. */
12463 zero_extended
= ((code
== EQ
|| code
== NE
12464 || code
== GEU
|| code
== GTU
12465 || code
== LEU
|| code
== LTU
)
12466 && (nonzero_bits (op0
, tmode
)
12467 & ~GET_MODE_MASK (mode
)) == 0
12468 && ((CONST_INT_P (op1
)
12469 || (nonzero_bits (op1
, tmode
)
12470 & ~GET_MODE_MASK (mode
)) == 0)));
12473 || ((num_sign_bit_copies (op0
, tmode
)
12474 > (unsigned int) (GET_MODE_PRECISION (tmode
)
12475 - GET_MODE_PRECISION (mode
)))
12476 && (num_sign_bit_copies (op1
, tmode
)
12477 > (unsigned int) (GET_MODE_PRECISION (tmode
)
12478 - GET_MODE_PRECISION (mode
)))))
12480 /* If OP0 is an AND and we don't have an AND in MODE either,
12481 make a new AND in the proper mode. */
12482 if (GET_CODE (op0
) == AND
12483 && !have_insn_for (AND
, mode
))
12484 op0
= simplify_gen_binary (AND
, tmode
,
12485 gen_lowpart (tmode
,
12487 gen_lowpart (tmode
,
12493 op0
= simplify_gen_unary (ZERO_EXTEND
, tmode
, op0
, mode
);
12494 op1
= simplify_gen_unary (ZERO_EXTEND
, tmode
, op1
, mode
);
12498 op0
= simplify_gen_unary (SIGN_EXTEND
, tmode
, op0
, mode
);
12499 op1
= simplify_gen_unary (SIGN_EXTEND
, tmode
, op1
, mode
);
12506 /* We may have changed the comparison operands. Re-canonicalize. */
12507 if (swap_commutative_operands_p (op0
, op1
))
12509 std::swap (op0
, op1
);
12510 code
= swap_condition (code
);
12513 /* If this machine only supports a subset of valid comparisons, see if we
12514 can convert an unsupported one into a supported one. */
12515 target_canonicalize_comparison (&code
, &op0
, &op1
, 0);
12523 /* Utility function for record_value_for_reg. Count number of
12528 enum rtx_code code
= GET_CODE (x
);
12532 if (GET_RTX_CLASS (code
) == RTX_BIN_ARITH
12533 || GET_RTX_CLASS (code
) == RTX_COMM_ARITH
)
12535 rtx x0
= XEXP (x
, 0);
12536 rtx x1
= XEXP (x
, 1);
12539 return 1 + 2 * count_rtxs (x0
);
12541 if ((GET_RTX_CLASS (GET_CODE (x1
)) == RTX_BIN_ARITH
12542 || GET_RTX_CLASS (GET_CODE (x1
)) == RTX_COMM_ARITH
)
12543 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
12544 return 2 + 2 * count_rtxs (x0
)
12545 + count_rtxs (x
== XEXP (x1
, 0)
12546 ? XEXP (x1
, 1) : XEXP (x1
, 0));
12548 if ((GET_RTX_CLASS (GET_CODE (x0
)) == RTX_BIN_ARITH
12549 || GET_RTX_CLASS (GET_CODE (x0
)) == RTX_COMM_ARITH
)
12550 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
12551 return 2 + 2 * count_rtxs (x1
)
12552 + count_rtxs (x
== XEXP (x0
, 0)
12553 ? XEXP (x0
, 1) : XEXP (x0
, 0));
12556 fmt
= GET_RTX_FORMAT (code
);
12557 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
12559 ret
+= count_rtxs (XEXP (x
, i
));
12560 else if (fmt
[i
] == 'E')
12561 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
12562 ret
+= count_rtxs (XVECEXP (x
, i
, j
));
12567 /* Utility function for following routine. Called when X is part of a value
12568 being stored into last_set_value. Sets last_set_table_tick
12569 for each register mentioned. Similar to mention_regs in cse.c */
12572 update_table_tick (rtx x
)
12574 enum rtx_code code
= GET_CODE (x
);
12575 const char *fmt
= GET_RTX_FORMAT (code
);
12580 unsigned int regno
= REGNO (x
);
12581 unsigned int endregno
= END_REGNO (x
);
12584 for (r
= regno
; r
< endregno
; r
++)
12586 reg_stat_type
*rsp
= ®_stat
[r
];
12587 rsp
->last_set_table_tick
= label_tick
;
12593 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
12596 /* Check for identical subexpressions. If x contains
12597 identical subexpression we only have to traverse one of
12599 if (i
== 0 && ARITHMETIC_P (x
))
12601 /* Note that at this point x1 has already been
12603 rtx x0
= XEXP (x
, 0);
12604 rtx x1
= XEXP (x
, 1);
12606 /* If x0 and x1 are identical then there is no need to
12611 /* If x0 is identical to a subexpression of x1 then while
12612 processing x1, x0 has already been processed. Thus we
12613 are done with x. */
12614 if (ARITHMETIC_P (x1
)
12615 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
12618 /* If x1 is identical to a subexpression of x0 then we
12619 still have to process the rest of x0. */
12620 if (ARITHMETIC_P (x0
)
12621 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
12623 update_table_tick (XEXP (x0
, x1
== XEXP (x0
, 0) ? 1 : 0));
12628 update_table_tick (XEXP (x
, i
));
12630 else if (fmt
[i
] == 'E')
12631 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
12632 update_table_tick (XVECEXP (x
, i
, j
));
12635 /* Record that REG is set to VALUE in insn INSN. If VALUE is zero, we
12636 are saying that the register is clobbered and we no longer know its
12637 value. If INSN is zero, don't update reg_stat[].last_set; this is
12638 only permitted with VALUE also zero and is used to invalidate the
12642 record_value_for_reg (rtx reg
, rtx_insn
*insn
, rtx value
)
12644 unsigned int regno
= REGNO (reg
);
12645 unsigned int endregno
= END_REGNO (reg
);
12647 reg_stat_type
*rsp
;
12649 /* If VALUE contains REG and we have a previous value for REG, substitute
12650 the previous value. */
12651 if (value
&& insn
&& reg_overlap_mentioned_p (reg
, value
))
12655 /* Set things up so get_last_value is allowed to see anything set up to
12657 subst_low_luid
= DF_INSN_LUID (insn
);
12658 tem
= get_last_value (reg
);
12660 /* If TEM is simply a binary operation with two CLOBBERs as operands,
12661 it isn't going to be useful and will take a lot of time to process,
12662 so just use the CLOBBER. */
12666 if (ARITHMETIC_P (tem
)
12667 && GET_CODE (XEXP (tem
, 0)) == CLOBBER
12668 && GET_CODE (XEXP (tem
, 1)) == CLOBBER
)
12669 tem
= XEXP (tem
, 0);
12670 else if (count_occurrences (value
, reg
, 1) >= 2)
12672 /* If there are two or more occurrences of REG in VALUE,
12673 prevent the value from growing too much. */
12674 if (count_rtxs (tem
) > MAX_LAST_VALUE_RTL
)
12675 tem
= gen_rtx_CLOBBER (GET_MODE (tem
), const0_rtx
);
12678 value
= replace_rtx (copy_rtx (value
), reg
, tem
);
12682 /* For each register modified, show we don't know its value, that
12683 we don't know about its bitwise content, that its value has been
12684 updated, and that we don't know the location of the death of the
12686 for (i
= regno
; i
< endregno
; i
++)
12688 rsp
= ®_stat
[i
];
12691 rsp
->last_set
= insn
;
12693 rsp
->last_set_value
= 0;
12694 rsp
->last_set_mode
= VOIDmode
;
12695 rsp
->last_set_nonzero_bits
= 0;
12696 rsp
->last_set_sign_bit_copies
= 0;
12697 rsp
->last_death
= 0;
12698 rsp
->truncated_to_mode
= VOIDmode
;
12701 /* Mark registers that are being referenced in this value. */
12703 update_table_tick (value
);
12705 /* Now update the status of each register being set.
12706 If someone is using this register in this block, set this register
12707 to invalid since we will get confused between the two lives in this
12708 basic block. This makes using this register always invalid. In cse, we
12709 scan the table to invalidate all entries using this register, but this
12710 is too much work for us. */
12712 for (i
= regno
; i
< endregno
; i
++)
12714 rsp
= ®_stat
[i
];
12715 rsp
->last_set_label
= label_tick
;
12717 || (value
&& rsp
->last_set_table_tick
>= label_tick_ebb_start
))
12718 rsp
->last_set_invalid
= 1;
12720 rsp
->last_set_invalid
= 0;
12723 /* The value being assigned might refer to X (like in "x++;"). In that
12724 case, we must replace it with (clobber (const_int 0)) to prevent
12726 rsp
= ®_stat
[regno
];
12727 if (value
&& !get_last_value_validate (&value
, insn
, label_tick
, 0))
12729 value
= copy_rtx (value
);
12730 if (!get_last_value_validate (&value
, insn
, label_tick
, 1))
12734 /* For the main register being modified, update the value, the mode, the
12735 nonzero bits, and the number of sign bit copies. */
12737 rsp
->last_set_value
= value
;
12741 machine_mode mode
= GET_MODE (reg
);
12742 subst_low_luid
= DF_INSN_LUID (insn
);
12743 rsp
->last_set_mode
= mode
;
12744 if (GET_MODE_CLASS (mode
) == MODE_INT
12745 && HWI_COMPUTABLE_MODE_P (mode
))
12746 mode
= nonzero_bits_mode
;
12747 rsp
->last_set_nonzero_bits
= nonzero_bits (value
, mode
);
12748 rsp
->last_set_sign_bit_copies
12749 = num_sign_bit_copies (value
, GET_MODE (reg
));
12753 /* Called via note_stores from record_dead_and_set_regs to handle one
12754 SET or CLOBBER in an insn. DATA is the instruction in which the
12755 set is occurring. */
12758 record_dead_and_set_regs_1 (rtx dest
, const_rtx setter
, void *data
)
12760 rtx_insn
*record_dead_insn
= (rtx_insn
*) data
;
12762 if (GET_CODE (dest
) == SUBREG
)
12763 dest
= SUBREG_REG (dest
);
12765 if (!record_dead_insn
)
12768 record_value_for_reg (dest
, NULL
, NULL_RTX
);
12774 /* If we are setting the whole register, we know its value. Otherwise
12775 show that we don't know the value. We can handle SUBREG in
12777 if (GET_CODE (setter
) == SET
&& dest
== SET_DEST (setter
))
12778 record_value_for_reg (dest
, record_dead_insn
, SET_SRC (setter
));
12779 else if (GET_CODE (setter
) == SET
12780 && GET_CODE (SET_DEST (setter
)) == SUBREG
12781 && SUBREG_REG (SET_DEST (setter
)) == dest
12782 && GET_MODE_PRECISION (GET_MODE (dest
)) <= BITS_PER_WORD
12783 && subreg_lowpart_p (SET_DEST (setter
)))
12784 record_value_for_reg (dest
, record_dead_insn
,
12785 gen_lowpart (GET_MODE (dest
),
12786 SET_SRC (setter
)));
12788 record_value_for_reg (dest
, record_dead_insn
, NULL_RTX
);
12790 else if (MEM_P (dest
)
12791 /* Ignore pushes, they clobber nothing. */
12792 && ! push_operand (dest
, GET_MODE (dest
)))
12793 mem_last_set
= DF_INSN_LUID (record_dead_insn
);
12796 /* Update the records of when each REG was most recently set or killed
12797 for the things done by INSN. This is the last thing done in processing
12798 INSN in the combiner loop.
12800 We update reg_stat[], in particular fields last_set, last_set_value,
12801 last_set_mode, last_set_nonzero_bits, last_set_sign_bit_copies,
12802 last_death, and also the similar information mem_last_set (which insn
12803 most recently modified memory) and last_call_luid (which insn was the
12804 most recent subroutine call). */
12807 record_dead_and_set_regs (rtx_insn
*insn
)
12812 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
12814 if (REG_NOTE_KIND (link
) == REG_DEAD
12815 && REG_P (XEXP (link
, 0)))
12817 unsigned int regno
= REGNO (XEXP (link
, 0));
12818 unsigned int endregno
= END_REGNO (XEXP (link
, 0));
12820 for (i
= regno
; i
< endregno
; i
++)
12822 reg_stat_type
*rsp
;
12824 rsp
= ®_stat
[i
];
12825 rsp
->last_death
= insn
;
12828 else if (REG_NOTE_KIND (link
) == REG_INC
)
12829 record_value_for_reg (XEXP (link
, 0), insn
, NULL_RTX
);
12834 hard_reg_set_iterator hrsi
;
12835 EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call
, 0, i
, hrsi
)
12837 reg_stat_type
*rsp
;
12839 rsp
= ®_stat
[i
];
12840 rsp
->last_set_invalid
= 1;
12841 rsp
->last_set
= insn
;
12842 rsp
->last_set_value
= 0;
12843 rsp
->last_set_mode
= VOIDmode
;
12844 rsp
->last_set_nonzero_bits
= 0;
12845 rsp
->last_set_sign_bit_copies
= 0;
12846 rsp
->last_death
= 0;
12847 rsp
->truncated_to_mode
= VOIDmode
;
12850 last_call_luid
= mem_last_set
= DF_INSN_LUID (insn
);
12852 /* We can't combine into a call pattern. Remember, though, that
12853 the return value register is set at this LUID. We could
12854 still replace a register with the return value from the
12855 wrong subroutine call! */
12856 note_stores (PATTERN (insn
), record_dead_and_set_regs_1
, NULL_RTX
);
12859 note_stores (PATTERN (insn
), record_dead_and_set_regs_1
, insn
);
12862 /* If a SUBREG has the promoted bit set, it is in fact a property of the
12863 register present in the SUBREG, so for each such SUBREG go back and
12864 adjust nonzero and sign bit information of the registers that are
12865 known to have some zero/sign bits set.
12867 This is needed because when combine blows the SUBREGs away, the
12868 information on zero/sign bits is lost and further combines can be
12869 missed because of that. */
12872 record_promoted_value (rtx_insn
*insn
, rtx subreg
)
12874 struct insn_link
*links
;
12876 unsigned int regno
= REGNO (SUBREG_REG (subreg
));
12877 machine_mode mode
= GET_MODE (subreg
);
12879 if (GET_MODE_PRECISION (mode
) > HOST_BITS_PER_WIDE_INT
)
12882 for (links
= LOG_LINKS (insn
); links
;)
12884 reg_stat_type
*rsp
;
12886 insn
= links
->insn
;
12887 set
= single_set (insn
);
12889 if (! set
|| !REG_P (SET_DEST (set
))
12890 || REGNO (SET_DEST (set
)) != regno
12891 || GET_MODE (SET_DEST (set
)) != GET_MODE (SUBREG_REG (subreg
)))
12893 links
= links
->next
;
12897 rsp
= ®_stat
[regno
];
12898 if (rsp
->last_set
== insn
)
12900 if (SUBREG_PROMOTED_UNSIGNED_P (subreg
))
12901 rsp
->last_set_nonzero_bits
&= GET_MODE_MASK (mode
);
12904 if (REG_P (SET_SRC (set
)))
12906 regno
= REGNO (SET_SRC (set
));
12907 links
= LOG_LINKS (insn
);
12914 /* Check if X, a register, is known to contain a value already
12915 truncated to MODE. In this case we can use a subreg to refer to
12916 the truncated value even though in the generic case we would need
12917 an explicit truncation. */
12920 reg_truncated_to_mode (machine_mode mode
, const_rtx x
)
12922 reg_stat_type
*rsp
= ®_stat
[REGNO (x
)];
12923 machine_mode truncated
= rsp
->truncated_to_mode
;
12926 || rsp
->truncation_label
< label_tick_ebb_start
)
12928 if (GET_MODE_SIZE (truncated
) <= GET_MODE_SIZE (mode
))
12930 if (TRULY_NOOP_TRUNCATION_MODES_P (mode
, truncated
))
12935 /* If X is a hard reg or a subreg record the mode that the register is
12936 accessed in. For non-TRULY_NOOP_TRUNCATION targets we might be able
12937 to turn a truncate into a subreg using this information. Return true
12938 if traversing X is complete. */
12941 record_truncated_value (rtx x
)
12943 machine_mode truncated_mode
;
12944 reg_stat_type
*rsp
;
12946 if (GET_CODE (x
) == SUBREG
&& REG_P (SUBREG_REG (x
)))
12948 machine_mode original_mode
= GET_MODE (SUBREG_REG (x
));
12949 truncated_mode
= GET_MODE (x
);
12951 if (GET_MODE_SIZE (original_mode
) <= GET_MODE_SIZE (truncated_mode
))
12954 if (TRULY_NOOP_TRUNCATION_MODES_P (truncated_mode
, original_mode
))
12957 x
= SUBREG_REG (x
);
12959 /* ??? For hard-regs we now record everything. We might be able to
12960 optimize this using last_set_mode. */
12961 else if (REG_P (x
) && REGNO (x
) < FIRST_PSEUDO_REGISTER
)
12962 truncated_mode
= GET_MODE (x
);
12966 rsp
= ®_stat
[REGNO (x
)];
12967 if (rsp
->truncated_to_mode
== 0
12968 || rsp
->truncation_label
< label_tick_ebb_start
12969 || (GET_MODE_SIZE (truncated_mode
)
12970 < GET_MODE_SIZE (rsp
->truncated_to_mode
)))
12972 rsp
->truncated_to_mode
= truncated_mode
;
12973 rsp
->truncation_label
= label_tick
;
12979 /* Callback for note_uses. Find hardregs and subregs of pseudos and
12980 the modes they are used in. This can help truning TRUNCATEs into
12984 record_truncated_values (rtx
*loc
, void *data ATTRIBUTE_UNUSED
)
12986 subrtx_var_iterator::array_type array
;
12987 FOR_EACH_SUBRTX_VAR (iter
, array
, *loc
, NONCONST
)
12988 if (record_truncated_value (*iter
))
12989 iter
.skip_subrtxes ();
12992 /* Scan X for promoted SUBREGs. For each one found,
12993 note what it implies to the registers used in it. */
12996 check_promoted_subreg (rtx_insn
*insn
, rtx x
)
12998 if (GET_CODE (x
) == SUBREG
12999 && SUBREG_PROMOTED_VAR_P (x
)
13000 && REG_P (SUBREG_REG (x
)))
13001 record_promoted_value (insn
, x
);
13004 const char *format
= GET_RTX_FORMAT (GET_CODE (x
));
13007 for (i
= 0; i
< GET_RTX_LENGTH (GET_CODE (x
)); i
++)
13011 check_promoted_subreg (insn
, XEXP (x
, i
));
13015 if (XVEC (x
, i
) != 0)
13016 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13017 check_promoted_subreg (insn
, XVECEXP (x
, i
, j
));
13023 /* Verify that all the registers and memory references mentioned in *LOC are
13024 still valid. *LOC was part of a value set in INSN when label_tick was
13025 equal to TICK. Return 0 if some are not. If REPLACE is nonzero, replace
13026 the invalid references with (clobber (const_int 0)) and return 1. This
13027 replacement is useful because we often can get useful information about
13028 the form of a value (e.g., if it was produced by a shift that always
13029 produces -1 or 0) even though we don't know exactly what registers it
13030 was produced from. */
13033 get_last_value_validate (rtx
*loc
, rtx_insn
*insn
, int tick
, int replace
)
13036 const char *fmt
= GET_RTX_FORMAT (GET_CODE (x
));
13037 int len
= GET_RTX_LENGTH (GET_CODE (x
));
13042 unsigned int regno
= REGNO (x
);
13043 unsigned int endregno
= END_REGNO (x
);
13046 for (j
= regno
; j
< endregno
; j
++)
13048 reg_stat_type
*rsp
= ®_stat
[j
];
13049 if (rsp
->last_set_invalid
13050 /* If this is a pseudo-register that was only set once and not
13051 live at the beginning of the function, it is always valid. */
13052 || (! (regno
>= FIRST_PSEUDO_REGISTER
13053 && regno
< reg_n_sets_max
13054 && REG_N_SETS (regno
) == 1
13055 && (!REGNO_REG_SET_P
13056 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
),
13058 && rsp
->last_set_label
> tick
))
13061 *loc
= gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
13068 /* If this is a memory reference, make sure that there were no stores after
13069 it that might have clobbered the value. We don't have alias info, so we
13070 assume any store invalidates it. Moreover, we only have local UIDs, so
13071 we also assume that there were stores in the intervening basic blocks. */
13072 else if (MEM_P (x
) && !MEM_READONLY_P (x
)
13073 && (tick
!= label_tick
|| DF_INSN_LUID (insn
) <= mem_last_set
))
13076 *loc
= gen_rtx_CLOBBER (GET_MODE (x
), const0_rtx
);
13080 for (i
= 0; i
< len
; i
++)
13084 /* Check for identical subexpressions. If x contains
13085 identical subexpression we only have to traverse one of
13087 if (i
== 1 && ARITHMETIC_P (x
))
13089 /* Note that at this point x0 has already been checked
13090 and found valid. */
13091 rtx x0
= XEXP (x
, 0);
13092 rtx x1
= XEXP (x
, 1);
13094 /* If x0 and x1 are identical then x is also valid. */
13098 /* If x1 is identical to a subexpression of x0 then
13099 while checking x0, x1 has already been checked. Thus
13100 it is valid and so as x. */
13101 if (ARITHMETIC_P (x0
)
13102 && (x1
== XEXP (x0
, 0) || x1
== XEXP (x0
, 1)))
13105 /* If x0 is identical to a subexpression of x1 then x is
13106 valid iff the rest of x1 is valid. */
13107 if (ARITHMETIC_P (x1
)
13108 && (x0
== XEXP (x1
, 0) || x0
== XEXP (x1
, 1)))
13110 get_last_value_validate (&XEXP (x1
,
13111 x0
== XEXP (x1
, 0) ? 1 : 0),
13112 insn
, tick
, replace
);
13115 if (get_last_value_validate (&XEXP (x
, i
), insn
, tick
,
13119 else if (fmt
[i
] == 'E')
13120 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13121 if (get_last_value_validate (&XVECEXP (x
, i
, j
),
13122 insn
, tick
, replace
) == 0)
13126 /* If we haven't found a reason for it to be invalid, it is valid. */
13130 /* Get the last value assigned to X, if known. Some registers
13131 in the value may be replaced with (clobber (const_int 0)) if their value
13132 is known longer known reliably. */
13135 get_last_value (const_rtx x
)
13137 unsigned int regno
;
13139 reg_stat_type
*rsp
;
13141 /* If this is a non-paradoxical SUBREG, get the value of its operand and
13142 then convert it to the desired mode. If this is a paradoxical SUBREG,
13143 we cannot predict what values the "extra" bits might have. */
13144 if (GET_CODE (x
) == SUBREG
13145 && subreg_lowpart_p (x
)
13146 && !paradoxical_subreg_p (x
)
13147 && (value
= get_last_value (SUBREG_REG (x
))) != 0)
13148 return gen_lowpart (GET_MODE (x
), value
);
13154 rsp
= ®_stat
[regno
];
13155 value
= rsp
->last_set_value
;
13157 /* If we don't have a value, or if it isn't for this basic block and
13158 it's either a hard register, set more than once, or it's a live
13159 at the beginning of the function, return 0.
13161 Because if it's not live at the beginning of the function then the reg
13162 is always set before being used (is never used without being set).
13163 And, if it's set only once, and it's always set before use, then all
13164 uses must have the same last value, even if it's not from this basic
13168 || (rsp
->last_set_label
< label_tick_ebb_start
13169 && (regno
< FIRST_PSEUDO_REGISTER
13170 || regno
>= reg_n_sets_max
13171 || REG_N_SETS (regno
) != 1
13173 (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
), regno
))))
13176 /* If the value was set in a later insn than the ones we are processing,
13177 we can't use it even if the register was only set once. */
13178 if (rsp
->last_set_label
== label_tick
13179 && DF_INSN_LUID (rsp
->last_set
) >= subst_low_luid
)
13182 /* If the value has all its registers valid, return it. */
13183 if (get_last_value_validate (&value
, rsp
->last_set
, rsp
->last_set_label
, 0))
13186 /* Otherwise, make a copy and replace any invalid register with
13187 (clobber (const_int 0)). If that fails for some reason, return 0. */
13189 value
= copy_rtx (value
);
13190 if (get_last_value_validate (&value
, rsp
->last_set
, rsp
->last_set_label
, 1))
13196 /* Return nonzero if expression X refers to a REG or to memory
13197 that is set in an instruction more recent than FROM_LUID. */
13200 use_crosses_set_p (const_rtx x
, int from_luid
)
13204 enum rtx_code code
= GET_CODE (x
);
13208 unsigned int regno
= REGNO (x
);
13209 unsigned endreg
= END_REGNO (x
);
13211 #ifdef PUSH_ROUNDING
13212 /* Don't allow uses of the stack pointer to be moved,
13213 because we don't know whether the move crosses a push insn. */
13214 if (regno
== STACK_POINTER_REGNUM
&& PUSH_ARGS
)
13217 for (; regno
< endreg
; regno
++)
13219 reg_stat_type
*rsp
= ®_stat
[regno
];
13221 && rsp
->last_set_label
== label_tick
13222 && DF_INSN_LUID (rsp
->last_set
) > from_luid
)
13228 if (code
== MEM
&& mem_last_set
> from_luid
)
13231 fmt
= GET_RTX_FORMAT (code
);
13233 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
13238 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
13239 if (use_crosses_set_p (XVECEXP (x
, i
, j
), from_luid
))
13242 else if (fmt
[i
] == 'e'
13243 && use_crosses_set_p (XEXP (x
, i
), from_luid
))
13249 /* Define three variables used for communication between the following
13252 static unsigned int reg_dead_regno
, reg_dead_endregno
;
13253 static int reg_dead_flag
;
13255 /* Function called via note_stores from reg_dead_at_p.
13257 If DEST is within [reg_dead_regno, reg_dead_endregno), set
13258 reg_dead_flag to 1 if X is a CLOBBER and to -1 it is a SET. */
13261 reg_dead_at_p_1 (rtx dest
, const_rtx x
, void *data ATTRIBUTE_UNUSED
)
13263 unsigned int regno
, endregno
;
13268 regno
= REGNO (dest
);
13269 endregno
= END_REGNO (dest
);
13270 if (reg_dead_endregno
> regno
&& reg_dead_regno
< endregno
)
13271 reg_dead_flag
= (GET_CODE (x
) == CLOBBER
) ? 1 : -1;
13274 /* Return nonzero if REG is known to be dead at INSN.
13276 We scan backwards from INSN. If we hit a REG_DEAD note or a CLOBBER
13277 referencing REG, it is dead. If we hit a SET referencing REG, it is
13278 live. Otherwise, see if it is live or dead at the start of the basic
13279 block we are in. Hard regs marked as being live in NEWPAT_USED_REGS
13280 must be assumed to be always live. */
13283 reg_dead_at_p (rtx reg
, rtx_insn
*insn
)
13288 /* Set variables for reg_dead_at_p_1. */
13289 reg_dead_regno
= REGNO (reg
);
13290 reg_dead_endregno
= END_REGNO (reg
);
13294 /* Check that reg isn't mentioned in NEWPAT_USED_REGS. For fixed registers
13295 we allow the machine description to decide whether use-and-clobber
13296 patterns are OK. */
13297 if (reg_dead_regno
< FIRST_PSEUDO_REGISTER
)
13299 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
13300 if (!fixed_regs
[i
] && TEST_HARD_REG_BIT (newpat_used_regs
, i
))
13304 /* Scan backwards until we find a REG_DEAD note, SET, CLOBBER, or
13305 beginning of basic block. */
13306 block
= BLOCK_FOR_INSN (insn
);
13311 if (find_regno_note (insn
, REG_UNUSED
, reg_dead_regno
))
13314 note_stores (PATTERN (insn
), reg_dead_at_p_1
, NULL
);
13316 return reg_dead_flag
== 1 ? 1 : 0;
13318 if (find_regno_note (insn
, REG_DEAD
, reg_dead_regno
))
13322 if (insn
== BB_HEAD (block
))
13325 insn
= PREV_INSN (insn
);
13328 /* Look at live-in sets for the basic block that we were in. */
13329 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
13330 if (REGNO_REG_SET_P (df_get_live_in (block
), i
))
13336 /* Note hard registers in X that are used. */
13339 mark_used_regs_combine (rtx x
)
13341 RTX_CODE code
= GET_CODE (x
);
13342 unsigned int regno
;
13353 case ADDR_DIFF_VEC
:
13355 /* CC0 must die in the insn after it is set, so we don't need to take
13356 special note of it here. */
13361 /* If we are clobbering a MEM, mark any hard registers inside the
13362 address as used. */
13363 if (MEM_P (XEXP (x
, 0)))
13364 mark_used_regs_combine (XEXP (XEXP (x
, 0), 0));
13369 /* A hard reg in a wide mode may really be multiple registers.
13370 If so, mark all of them just like the first. */
13371 if (regno
< FIRST_PSEUDO_REGISTER
)
13373 /* None of this applies to the stack, frame or arg pointers. */
13374 if (regno
== STACK_POINTER_REGNUM
13375 || (!HARD_FRAME_POINTER_IS_FRAME_POINTER
13376 && regno
== HARD_FRAME_POINTER_REGNUM
)
13377 || (FRAME_POINTER_REGNUM
!= ARG_POINTER_REGNUM
13378 && regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
13379 || regno
== FRAME_POINTER_REGNUM
)
13382 add_to_hard_reg_set (&newpat_used_regs
, GET_MODE (x
), regno
);
13388 /* If setting a MEM, or a SUBREG of a MEM, then note any hard regs in
13390 rtx testreg
= SET_DEST (x
);
13392 while (GET_CODE (testreg
) == SUBREG
13393 || GET_CODE (testreg
) == ZERO_EXTRACT
13394 || GET_CODE (testreg
) == STRICT_LOW_PART
)
13395 testreg
= XEXP (testreg
, 0);
13397 if (MEM_P (testreg
))
13398 mark_used_regs_combine (XEXP (testreg
, 0));
13400 mark_used_regs_combine (SET_SRC (x
));
13408 /* Recursively scan the operands of this expression. */
13411 const char *fmt
= GET_RTX_FORMAT (code
);
13413 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
13416 mark_used_regs_combine (XEXP (x
, i
));
13417 else if (fmt
[i
] == 'E')
13421 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
13422 mark_used_regs_combine (XVECEXP (x
, i
, j
));
13428 /* Remove register number REGNO from the dead registers list of INSN.
13430 Return the note used to record the death, if there was one. */
13433 remove_death (unsigned int regno
, rtx_insn
*insn
)
13435 rtx note
= find_regno_note (insn
, REG_DEAD
, regno
);
13438 remove_note (insn
, note
);
13443 /* For each register (hardware or pseudo) used within expression X, if its
13444 death is in an instruction with luid between FROM_LUID (inclusive) and
13445 TO_INSN (exclusive), put a REG_DEAD note for that register in the
13446 list headed by PNOTES.
13448 That said, don't move registers killed by maybe_kill_insn.
13450 This is done when X is being merged by combination into TO_INSN. These
13451 notes will then be distributed as needed. */
13454 move_deaths (rtx x
, rtx maybe_kill_insn
, int from_luid
, rtx_insn
*to_insn
,
13459 enum rtx_code code
= GET_CODE (x
);
13463 unsigned int regno
= REGNO (x
);
13464 rtx_insn
*where_dead
= reg_stat
[regno
].last_death
;
13466 /* Don't move the register if it gets killed in between from and to. */
13467 if (maybe_kill_insn
&& reg_set_p (x
, maybe_kill_insn
)
13468 && ! reg_referenced_p (x
, maybe_kill_insn
))
13472 && BLOCK_FOR_INSN (where_dead
) == BLOCK_FOR_INSN (to_insn
)
13473 && DF_INSN_LUID (where_dead
) >= from_luid
13474 && DF_INSN_LUID (where_dead
) < DF_INSN_LUID (to_insn
))
13476 rtx note
= remove_death (regno
, where_dead
);
13478 /* It is possible for the call above to return 0. This can occur
13479 when last_death points to I2 or I1 that we combined with.
13480 In that case make a new note.
13482 We must also check for the case where X is a hard register
13483 and NOTE is a death note for a range of hard registers
13484 including X. In that case, we must put REG_DEAD notes for
13485 the remaining registers in place of NOTE. */
13487 if (note
!= 0 && regno
< FIRST_PSEUDO_REGISTER
13488 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
13489 > GET_MODE_SIZE (GET_MODE (x
))))
13491 unsigned int deadregno
= REGNO (XEXP (note
, 0));
13492 unsigned int deadend
= END_REGNO (XEXP (note
, 0));
13493 unsigned int ourend
= END_REGNO (x
);
13496 for (i
= deadregno
; i
< deadend
; i
++)
13497 if (i
< regno
|| i
>= ourend
)
13498 add_reg_note (where_dead
, REG_DEAD
, regno_reg_rtx
[i
]);
13501 /* If we didn't find any note, or if we found a REG_DEAD note that
13502 covers only part of the given reg, and we have a multi-reg hard
13503 register, then to be safe we must check for REG_DEAD notes
13504 for each register other than the first. They could have
13505 their own REG_DEAD notes lying around. */
13506 else if ((note
== 0
13508 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
13509 < GET_MODE_SIZE (GET_MODE (x
)))))
13510 && regno
< FIRST_PSEUDO_REGISTER
13511 && REG_NREGS (x
) > 1)
13513 unsigned int ourend
= END_REGNO (x
);
13514 unsigned int i
, offset
;
13518 offset
= hard_regno_nregs
[regno
][GET_MODE (XEXP (note
, 0))];
13522 for (i
= regno
+ offset
; i
< ourend
; i
++)
13523 move_deaths (regno_reg_rtx
[i
],
13524 maybe_kill_insn
, from_luid
, to_insn
, &oldnotes
);
13527 if (note
!= 0 && GET_MODE (XEXP (note
, 0)) == GET_MODE (x
))
13529 XEXP (note
, 1) = *pnotes
;
13533 *pnotes
= alloc_reg_note (REG_DEAD
, x
, *pnotes
);
13539 else if (GET_CODE (x
) == SET
)
13541 rtx dest
= SET_DEST (x
);
13543 move_deaths (SET_SRC (x
), maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13545 /* In the case of a ZERO_EXTRACT, a STRICT_LOW_PART, or a SUBREG
13546 that accesses one word of a multi-word item, some
13547 piece of everything register in the expression is used by
13548 this insn, so remove any old death. */
13549 /* ??? So why do we test for equality of the sizes? */
13551 if (GET_CODE (dest
) == ZERO_EXTRACT
13552 || GET_CODE (dest
) == STRICT_LOW_PART
13553 || (GET_CODE (dest
) == SUBREG
13554 && (((GET_MODE_SIZE (GET_MODE (dest
))
13555 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
13556 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest
)))
13557 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))))
13559 move_deaths (dest
, maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13563 /* If this is some other SUBREG, we know it replaces the entire
13564 value, so use that as the destination. */
13565 if (GET_CODE (dest
) == SUBREG
)
13566 dest
= SUBREG_REG (dest
);
13568 /* If this is a MEM, adjust deaths of anything used in the address.
13569 For a REG (the only other possibility), the entire value is
13570 being replaced so the old value is not used in this insn. */
13573 move_deaths (XEXP (dest
, 0), maybe_kill_insn
, from_luid
,
13578 else if (GET_CODE (x
) == CLOBBER
)
13581 len
= GET_RTX_LENGTH (code
);
13582 fmt
= GET_RTX_FORMAT (code
);
13584 for (i
= 0; i
< len
; i
++)
13589 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
13590 move_deaths (XVECEXP (x
, i
, j
), maybe_kill_insn
, from_luid
,
13593 else if (fmt
[i
] == 'e')
13594 move_deaths (XEXP (x
, i
), maybe_kill_insn
, from_luid
, to_insn
, pnotes
);
13598 /* Return 1 if X is the target of a bit-field assignment in BODY, the
13599 pattern of an insn. X must be a REG. */
13602 reg_bitfield_target_p (rtx x
, rtx body
)
13606 if (GET_CODE (body
) == SET
)
13608 rtx dest
= SET_DEST (body
);
13610 unsigned int regno
, tregno
, endregno
, endtregno
;
13612 if (GET_CODE (dest
) == ZERO_EXTRACT
)
13613 target
= XEXP (dest
, 0);
13614 else if (GET_CODE (dest
) == STRICT_LOW_PART
)
13615 target
= SUBREG_REG (XEXP (dest
, 0));
13619 if (GET_CODE (target
) == SUBREG
)
13620 target
= SUBREG_REG (target
);
13622 if (!REG_P (target
))
13625 tregno
= REGNO (target
), regno
= REGNO (x
);
13626 if (tregno
>= FIRST_PSEUDO_REGISTER
|| regno
>= FIRST_PSEUDO_REGISTER
)
13627 return target
== x
;
13629 endtregno
= end_hard_regno (GET_MODE (target
), tregno
);
13630 endregno
= end_hard_regno (GET_MODE (x
), regno
);
13632 return endregno
> tregno
&& regno
< endtregno
;
13635 else if (GET_CODE (body
) == PARALLEL
)
13636 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
13637 if (reg_bitfield_target_p (x
, XVECEXP (body
, 0, i
)))
13643 /* Given a chain of REG_NOTES originally from FROM_INSN, try to place them
13644 as appropriate. I3 and I2 are the insns resulting from the combination
13645 insns including FROM (I2 may be zero).
13647 ELIM_I2 and ELIM_I1 are either zero or registers that we know will
13648 not need REG_DEAD notes because they are being substituted for. This
13649 saves searching in the most common cases.
13651 Each note in the list is either ignored or placed on some insns, depending
13652 on the type of note. */
13655 distribute_notes (rtx notes
, rtx_insn
*from_insn
, rtx_insn
*i3
, rtx_insn
*i2
,
13656 rtx elim_i2
, rtx elim_i1
, rtx elim_i0
)
13658 rtx note
, next_note
;
13660 rtx_insn
*tem_insn
;
13662 for (note
= notes
; note
; note
= next_note
)
13664 rtx_insn
*place
= 0, *place2
= 0;
13666 next_note
= XEXP (note
, 1);
13667 switch (REG_NOTE_KIND (note
))
13671 /* Doesn't matter much where we put this, as long as it's somewhere.
13672 It is preferable to keep these notes on branches, which is most
13673 likely to be i3. */
13677 case REG_NON_LOCAL_GOTO
:
13682 gcc_assert (i2
&& JUMP_P (i2
));
13687 case REG_EH_REGION
:
13688 /* These notes must remain with the call or trapping instruction. */
13691 else if (i2
&& CALL_P (i2
))
13695 gcc_assert (cfun
->can_throw_non_call_exceptions
);
13696 if (may_trap_p (i3
))
13698 else if (i2
&& may_trap_p (i2
))
13700 /* ??? Otherwise assume we've combined things such that we
13701 can now prove that the instructions can't trap. Drop the
13702 note in this case. */
13706 case REG_ARGS_SIZE
:
13707 /* ??? How to distribute between i3-i1. Assume i3 contains the
13708 entire adjustment. Assert i3 contains at least some adjust. */
13709 if (!noop_move_p (i3
))
13711 int old_size
, args_size
= INTVAL (XEXP (note
, 0));
13712 /* fixup_args_size_notes looks at REG_NORETURN note,
13713 so ensure the note is placed there first. */
13717 for (np
= &next_note
; *np
; np
= &XEXP (*np
, 1))
13718 if (REG_NOTE_KIND (*np
) == REG_NORETURN
)
13722 XEXP (n
, 1) = REG_NOTES (i3
);
13723 REG_NOTES (i3
) = n
;
13727 old_size
= fixup_args_size_notes (PREV_INSN (i3
), i3
, args_size
);
13728 /* emit_call_1 adds for !ACCUMULATE_OUTGOING_ARGS
13729 REG_ARGS_SIZE note to all noreturn calls, allow that here. */
13730 gcc_assert (old_size
!= args_size
13732 && !ACCUMULATE_OUTGOING_ARGS
13733 && find_reg_note (i3
, REG_NORETURN
, NULL_RTX
)));
13740 case REG_CALL_DECL
:
13741 /* These notes must remain with the call. It should not be
13742 possible for both I2 and I3 to be a call. */
13747 gcc_assert (i2
&& CALL_P (i2
));
13753 /* Any clobbers for i3 may still exist, and so we must process
13754 REG_UNUSED notes from that insn.
13756 Any clobbers from i2 or i1 can only exist if they were added by
13757 recog_for_combine. In that case, recog_for_combine created the
13758 necessary REG_UNUSED notes. Trying to keep any original
13759 REG_UNUSED notes from these insns can cause incorrect output
13760 if it is for the same register as the original i3 dest.
13761 In that case, we will notice that the register is set in i3,
13762 and then add a REG_UNUSED note for the destination of i3, which
13763 is wrong. However, it is possible to have REG_UNUSED notes from
13764 i2 or i1 for register which were both used and clobbered, so
13765 we keep notes from i2 or i1 if they will turn into REG_DEAD
13768 /* If this register is set or clobbered in I3, put the note there
13769 unless there is one already. */
13770 if (reg_set_p (XEXP (note
, 0), PATTERN (i3
)))
13772 if (from_insn
!= i3
)
13775 if (! (REG_P (XEXP (note
, 0))
13776 ? find_regno_note (i3
, REG_UNUSED
, REGNO (XEXP (note
, 0)))
13777 : find_reg_note (i3
, REG_UNUSED
, XEXP (note
, 0))))
13780 /* Otherwise, if this register is used by I3, then this register
13781 now dies here, so we must put a REG_DEAD note here unless there
13783 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
))
13784 && ! (REG_P (XEXP (note
, 0))
13785 ? find_regno_note (i3
, REG_DEAD
,
13786 REGNO (XEXP (note
, 0)))
13787 : find_reg_note (i3
, REG_DEAD
, XEXP (note
, 0))))
13789 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
13797 /* These notes say something about results of an insn. We can
13798 only support them if they used to be on I3 in which case they
13799 remain on I3. Otherwise they are ignored.
13801 If the note refers to an expression that is not a constant, we
13802 must also ignore the note since we cannot tell whether the
13803 equivalence is still true. It might be possible to do
13804 slightly better than this (we only have a problem if I2DEST
13805 or I1DEST is present in the expression), but it doesn't
13806 seem worth the trouble. */
13808 if (from_insn
== i3
13809 && (XEXP (note
, 0) == 0 || CONSTANT_P (XEXP (note
, 0))))
13814 /* These notes say something about how a register is used. They must
13815 be present on any use of the register in I2 or I3. */
13816 if (reg_mentioned_p (XEXP (note
, 0), PATTERN (i3
)))
13819 if (i2
&& reg_mentioned_p (XEXP (note
, 0), PATTERN (i2
)))
13828 case REG_LABEL_TARGET
:
13829 case REG_LABEL_OPERAND
:
13830 /* This can show up in several ways -- either directly in the
13831 pattern, or hidden off in the constant pool with (or without?)
13832 a REG_EQUAL note. */
13833 /* ??? Ignore the without-reg_equal-note problem for now. */
13834 if (reg_mentioned_p (XEXP (note
, 0), PATTERN (i3
))
13835 || ((tem_note
= find_reg_note (i3
, REG_EQUAL
, NULL_RTX
))
13836 && GET_CODE (XEXP (tem_note
, 0)) == LABEL_REF
13837 && LABEL_REF_LABEL (XEXP (tem_note
, 0)) == XEXP (note
, 0)))
13841 && (reg_mentioned_p (XEXP (note
, 0), PATTERN (i2
))
13842 || ((tem_note
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
))
13843 && GET_CODE (XEXP (tem_note
, 0)) == LABEL_REF
13844 && LABEL_REF_LABEL (XEXP (tem_note
, 0)) == XEXP (note
, 0))))
13852 /* For REG_LABEL_TARGET on a JUMP_P, we prefer to put the note
13853 as a JUMP_LABEL or decrement LABEL_NUSES if it's already
13855 if (place
&& JUMP_P (place
)
13856 && REG_NOTE_KIND (note
) == REG_LABEL_TARGET
13857 && (JUMP_LABEL (place
) == NULL
13858 || JUMP_LABEL (place
) == XEXP (note
, 0)))
13860 rtx label
= JUMP_LABEL (place
);
13863 JUMP_LABEL (place
) = XEXP (note
, 0);
13864 else if (LABEL_P (label
))
13865 LABEL_NUSES (label
)--;
13868 if (place2
&& JUMP_P (place2
)
13869 && REG_NOTE_KIND (note
) == REG_LABEL_TARGET
13870 && (JUMP_LABEL (place2
) == NULL
13871 || JUMP_LABEL (place2
) == XEXP (note
, 0)))
13873 rtx label
= JUMP_LABEL (place2
);
13876 JUMP_LABEL (place2
) = XEXP (note
, 0);
13877 else if (LABEL_P (label
))
13878 LABEL_NUSES (label
)--;
13884 /* This note says something about the value of a register prior
13885 to the execution of an insn. It is too much trouble to see
13886 if the note is still correct in all situations. It is better
13887 to simply delete it. */
13891 /* If we replaced the right hand side of FROM_INSN with a
13892 REG_EQUAL note, the original use of the dying register
13893 will not have been combined into I3 and I2. In such cases,
13894 FROM_INSN is guaranteed to be the first of the combined
13895 instructions, so we simply need to search back before
13896 FROM_INSN for the previous use or set of this register,
13897 then alter the notes there appropriately.
13899 If the register is used as an input in I3, it dies there.
13900 Similarly for I2, if it is nonzero and adjacent to I3.
13902 If the register is not used as an input in either I3 or I2
13903 and it is not one of the registers we were supposed to eliminate,
13904 there are two possibilities. We might have a non-adjacent I2
13905 or we might have somehow eliminated an additional register
13906 from a computation. For example, we might have had A & B where
13907 we discover that B will always be zero. In this case we will
13908 eliminate the reference to A.
13910 In both cases, we must search to see if we can find a previous
13911 use of A and put the death note there. */
13914 && from_insn
== i2mod
13915 && !reg_overlap_mentioned_p (XEXP (note
, 0), i2mod_new_rhs
))
13916 tem_insn
= from_insn
;
13920 && CALL_P (from_insn
)
13921 && find_reg_fusage (from_insn
, USE
, XEXP (note
, 0)))
13923 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
)))
13925 else if (i2
!= 0 && next_nonnote_nondebug_insn (i2
) == i3
13926 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
13928 else if ((rtx_equal_p (XEXP (note
, 0), elim_i2
)
13930 && reg_overlap_mentioned_p (XEXP (note
, 0),
13932 || rtx_equal_p (XEXP (note
, 0), elim_i1
)
13933 || rtx_equal_p (XEXP (note
, 0), elim_i0
))
13936 /* If the new I2 sets the same register that is marked dead
13937 in the note, we do not know where to put the note.
13939 if (i2
!= 0 && reg_set_p (XEXP (note
, 0), PATTERN (i2
)))
13945 basic_block bb
= this_basic_block
;
13947 for (tem_insn
= PREV_INSN (tem_insn
); place
== 0; tem_insn
= PREV_INSN (tem_insn
))
13949 if (!NONDEBUG_INSN_P (tem_insn
))
13951 if (tem_insn
== BB_HEAD (bb
))
13956 /* If the register is being set at TEM_INSN, see if that is all
13957 TEM_INSN is doing. If so, delete TEM_INSN. Otherwise, make this
13958 into a REG_UNUSED note instead. Don't delete sets to
13959 global register vars. */
13960 if ((REGNO (XEXP (note
, 0)) >= FIRST_PSEUDO_REGISTER
13961 || !global_regs
[REGNO (XEXP (note
, 0))])
13962 && reg_set_p (XEXP (note
, 0), PATTERN (tem_insn
)))
13964 rtx set
= single_set (tem_insn
);
13965 rtx inner_dest
= 0;
13966 rtx_insn
*cc0_setter
= NULL
;
13969 for (inner_dest
= SET_DEST (set
);
13970 (GET_CODE (inner_dest
) == STRICT_LOW_PART
13971 || GET_CODE (inner_dest
) == SUBREG
13972 || GET_CODE (inner_dest
) == ZERO_EXTRACT
);
13973 inner_dest
= XEXP (inner_dest
, 0))
13976 /* Verify that it was the set, and not a clobber that
13977 modified the register.
13979 CC0 targets must be careful to maintain setter/user
13980 pairs. If we cannot delete the setter due to side
13981 effects, mark the user with an UNUSED note instead
13984 if (set
!= 0 && ! side_effects_p (SET_SRC (set
))
13985 && rtx_equal_p (XEXP (note
, 0), inner_dest
)
13987 || (! reg_mentioned_p (cc0_rtx
, SET_SRC (set
))
13988 || ((cc0_setter
= prev_cc0_setter (tem_insn
)) != NULL
13989 && sets_cc0_p (PATTERN (cc0_setter
)) > 0))))
13991 /* Move the notes and links of TEM_INSN elsewhere.
13992 This might delete other dead insns recursively.
13993 First set the pattern to something that won't use
13995 rtx old_notes
= REG_NOTES (tem_insn
);
13997 PATTERN (tem_insn
) = pc_rtx
;
13998 REG_NOTES (tem_insn
) = NULL
;
14000 distribute_notes (old_notes
, tem_insn
, tem_insn
, NULL
,
14001 NULL_RTX
, NULL_RTX
, NULL_RTX
);
14002 distribute_links (LOG_LINKS (tem_insn
));
14004 SET_INSN_DELETED (tem_insn
);
14005 if (tem_insn
== i2
)
14008 /* Delete the setter too. */
14011 PATTERN (cc0_setter
) = pc_rtx
;
14012 old_notes
= REG_NOTES (cc0_setter
);
14013 REG_NOTES (cc0_setter
) = NULL
;
14015 distribute_notes (old_notes
, cc0_setter
,
14017 NULL_RTX
, NULL_RTX
, NULL_RTX
);
14018 distribute_links (LOG_LINKS (cc0_setter
));
14020 SET_INSN_DELETED (cc0_setter
);
14021 if (cc0_setter
== i2
)
14027 PUT_REG_NOTE_KIND (note
, REG_UNUSED
);
14029 /* If there isn't already a REG_UNUSED note, put one
14030 here. Do not place a REG_DEAD note, even if
14031 the register is also used here; that would not
14032 match the algorithm used in lifetime analysis
14033 and can cause the consistency check in the
14034 scheduler to fail. */
14035 if (! find_regno_note (tem_insn
, REG_UNUSED
,
14036 REGNO (XEXP (note
, 0))))
14041 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (tem_insn
))
14042 || (CALL_P (tem_insn
)
14043 && find_reg_fusage (tem_insn
, USE
, XEXP (note
, 0))))
14047 /* If we are doing a 3->2 combination, and we have a
14048 register which formerly died in i3 and was not used
14049 by i2, which now no longer dies in i3 and is used in
14050 i2 but does not die in i2, and place is between i2
14051 and i3, then we may need to move a link from place to
14053 if (i2
&& DF_INSN_LUID (place
) > DF_INSN_LUID (i2
)
14055 && DF_INSN_LUID (from_insn
) > DF_INSN_LUID (i2
)
14056 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
14058 struct insn_link
*links
= LOG_LINKS (place
);
14059 LOG_LINKS (place
) = NULL
;
14060 distribute_links (links
);
14065 if (tem_insn
== BB_HEAD (bb
))
14071 /* If the register is set or already dead at PLACE, we needn't do
14072 anything with this note if it is still a REG_DEAD note.
14073 We check here if it is set at all, not if is it totally replaced,
14074 which is what `dead_or_set_p' checks, so also check for it being
14077 if (place
&& REG_NOTE_KIND (note
) == REG_DEAD
)
14079 unsigned int regno
= REGNO (XEXP (note
, 0));
14080 reg_stat_type
*rsp
= ®_stat
[regno
];
14082 if (dead_or_set_p (place
, XEXP (note
, 0))
14083 || reg_bitfield_target_p (XEXP (note
, 0), PATTERN (place
)))
14085 /* Unless the register previously died in PLACE, clear
14086 last_death. [I no longer understand why this is
14088 if (rsp
->last_death
!= place
)
14089 rsp
->last_death
= 0;
14093 rsp
->last_death
= place
;
14095 /* If this is a death note for a hard reg that is occupying
14096 multiple registers, ensure that we are still using all
14097 parts of the object. If we find a piece of the object
14098 that is unused, we must arrange for an appropriate REG_DEAD
14099 note to be added for it. However, we can't just emit a USE
14100 and tag the note to it, since the register might actually
14101 be dead; so we recourse, and the recursive call then finds
14102 the previous insn that used this register. */
14104 if (place
&& REG_NREGS (XEXP (note
, 0)) > 1)
14106 unsigned int endregno
= END_REGNO (XEXP (note
, 0));
14107 bool all_used
= true;
14110 for (i
= regno
; i
< endregno
; i
++)
14111 if ((! refers_to_regno_p (i
, PATTERN (place
))
14112 && ! find_regno_fusage (place
, USE
, i
))
14113 || dead_or_set_regno_p (place
, i
))
14121 /* Put only REG_DEAD notes for pieces that are
14122 not already dead or set. */
14124 for (i
= regno
; i
< endregno
;
14125 i
+= hard_regno_nregs
[i
][reg_raw_mode
[i
]])
14127 rtx piece
= regno_reg_rtx
[i
];
14128 basic_block bb
= this_basic_block
;
14130 if (! dead_or_set_p (place
, piece
)
14131 && ! reg_bitfield_target_p (piece
,
14134 rtx new_note
= alloc_reg_note (REG_DEAD
, piece
,
14137 distribute_notes (new_note
, place
, place
,
14138 NULL
, NULL_RTX
, NULL_RTX
,
14141 else if (! refers_to_regno_p (i
, PATTERN (place
))
14142 && ! find_regno_fusage (place
, USE
, i
))
14143 for (tem_insn
= PREV_INSN (place
); ;
14144 tem_insn
= PREV_INSN (tem_insn
))
14146 if (!NONDEBUG_INSN_P (tem_insn
))
14148 if (tem_insn
== BB_HEAD (bb
))
14152 if (dead_or_set_p (tem_insn
, piece
)
14153 || reg_bitfield_target_p (piece
,
14154 PATTERN (tem_insn
)))
14156 add_reg_note (tem_insn
, REG_UNUSED
, piece
);
14169 /* Any other notes should not be present at this point in the
14171 gcc_unreachable ();
14176 XEXP (note
, 1) = REG_NOTES (place
);
14177 REG_NOTES (place
) = note
;
14181 add_shallow_copy_of_reg_note (place2
, note
);
14185 /* Similarly to above, distribute the LOG_LINKS that used to be present on
14186 I3, I2, and I1 to new locations. This is also called to add a link
14187 pointing at I3 when I3's destination is changed. */
14190 distribute_links (struct insn_link
*links
)
14192 struct insn_link
*link
, *next_link
;
14194 for (link
= links
; link
; link
= next_link
)
14196 rtx_insn
*place
= 0;
14200 next_link
= link
->next
;
14202 /* If the insn that this link points to is a NOTE, ignore it. */
14203 if (NOTE_P (link
->insn
))
14207 rtx pat
= PATTERN (link
->insn
);
14208 if (GET_CODE (pat
) == SET
)
14210 else if (GET_CODE (pat
) == PARALLEL
)
14213 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
14215 set
= XVECEXP (pat
, 0, i
);
14216 if (GET_CODE (set
) != SET
)
14219 reg
= SET_DEST (set
);
14220 while (GET_CODE (reg
) == ZERO_EXTRACT
14221 || GET_CODE (reg
) == STRICT_LOW_PART
14222 || GET_CODE (reg
) == SUBREG
)
14223 reg
= XEXP (reg
, 0);
14228 if (REGNO (reg
) == link
->regno
)
14231 if (i
== XVECLEN (pat
, 0))
14237 reg
= SET_DEST (set
);
14239 while (GET_CODE (reg
) == ZERO_EXTRACT
14240 || GET_CODE (reg
) == STRICT_LOW_PART
14241 || GET_CODE (reg
) == SUBREG
)
14242 reg
= XEXP (reg
, 0);
14244 /* A LOG_LINK is defined as being placed on the first insn that uses
14245 a register and points to the insn that sets the register. Start
14246 searching at the next insn after the target of the link and stop
14247 when we reach a set of the register or the end of the basic block.
14249 Note that this correctly handles the link that used to point from
14250 I3 to I2. Also note that not much searching is typically done here
14251 since most links don't point very far away. */
14253 for (insn
= NEXT_INSN (link
->insn
);
14254 (insn
&& (this_basic_block
->next_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
14255 || BB_HEAD (this_basic_block
->next_bb
) != insn
));
14256 insn
= NEXT_INSN (insn
))
14257 if (DEBUG_INSN_P (insn
))
14259 else if (INSN_P (insn
) && reg_overlap_mentioned_p (reg
, PATTERN (insn
)))
14261 if (reg_referenced_p (reg
, PATTERN (insn
)))
14265 else if (CALL_P (insn
)
14266 && find_reg_fusage (insn
, USE
, reg
))
14271 else if (INSN_P (insn
) && reg_set_p (reg
, insn
))
14274 /* If we found a place to put the link, place it there unless there
14275 is already a link to the same insn as LINK at that point. */
14279 struct insn_link
*link2
;
14281 FOR_EACH_LOG_LINK (link2
, place
)
14282 if (link2
->insn
== link
->insn
&& link2
->regno
== link
->regno
)
14287 link
->next
= LOG_LINKS (place
);
14288 LOG_LINKS (place
) = link
;
14290 /* Set added_links_insn to the earliest insn we added a
14292 if (added_links_insn
== 0
14293 || DF_INSN_LUID (added_links_insn
) > DF_INSN_LUID (place
))
14294 added_links_insn
= place
;
14300 /* Check for any register or memory mentioned in EQUIV that is not
14301 mentioned in EXPR. This is used to restrict EQUIV to "specializations"
14302 of EXPR where some registers may have been replaced by constants. */
14305 unmentioned_reg_p (rtx equiv
, rtx expr
)
14307 subrtx_iterator::array_type array
;
14308 FOR_EACH_SUBRTX (iter
, array
, equiv
, NONCONST
)
14310 const_rtx x
= *iter
;
14311 if ((REG_P (x
) || MEM_P (x
))
14312 && !reg_mentioned_p (x
, expr
))
14318 DEBUG_FUNCTION
void
14319 dump_combine_stats (FILE *file
)
14323 ";; Combiner statistics: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n\n",
14324 combine_attempts
, combine_merges
, combine_extras
, combine_successes
);
14328 dump_combine_total_stats (FILE *file
)
14332 "\n;; Combiner totals: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n",
14333 total_attempts
, total_merges
, total_extras
, total_successes
);
14336 /* Try combining insns through substitution. */
14337 static unsigned int
14338 rest_of_handle_combine (void)
14340 int rebuild_jump_labels_after_combine
;
14342 df_set_flags (DF_LR_RUN_DCE
+ DF_DEFER_INSN_RESCAN
);
14343 df_note_add_problem ();
14346 regstat_init_n_sets_and_refs ();
14347 reg_n_sets_max
= max_reg_num ();
14349 rebuild_jump_labels_after_combine
14350 = combine_instructions (get_insns (), max_reg_num ());
14352 /* Combining insns may have turned an indirect jump into a
14353 direct jump. Rebuild the JUMP_LABEL fields of jumping
14355 if (rebuild_jump_labels_after_combine
)
14357 timevar_push (TV_JUMP
);
14358 rebuild_jump_labels (get_insns ());
14360 timevar_pop (TV_JUMP
);
14363 regstat_free_n_sets_and_refs ();
14369 const pass_data pass_data_combine
=
14371 RTL_PASS
, /* type */
14372 "combine", /* name */
14373 OPTGROUP_NONE
, /* optinfo_flags */
14374 TV_COMBINE
, /* tv_id */
14375 PROP_cfglayout
, /* properties_required */
14376 0, /* properties_provided */
14377 0, /* properties_destroyed */
14378 0, /* todo_flags_start */
14379 TODO_df_finish
, /* todo_flags_finish */
14382 class pass_combine
: public rtl_opt_pass
14385 pass_combine (gcc::context
*ctxt
)
14386 : rtl_opt_pass (pass_data_combine
, ctxt
)
14389 /* opt_pass methods: */
14390 virtual bool gate (function
*) { return (optimize
> 0); }
14391 virtual unsigned int execute (function
*)
14393 return rest_of_handle_combine ();
14396 }; // class pass_combine
14398 } // anon namespace
14401 make_pass_combine (gcc::context
*ctxt
)
14403 return new pass_combine (ctxt
);