1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED, REG_N_THROWING_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery
116 - global property computation
118 - pre/post modify transformation
123 #include "coretypes.h"
128 #include "hard-reg-set.h"
129 #include "basic-block.h"
130 #include "insn-config.h"
134 #include "function.h"
142 #include "splay-tree.h"
143 #include "tree-pass.h"
146 #ifndef HAVE_epilogue
147 #define HAVE_epilogue 0
149 #ifndef HAVE_prologue
150 #define HAVE_prologue 0
152 #ifndef HAVE_sibcall_epilogue
153 #define HAVE_sibcall_epilogue 0
156 #ifndef EPILOGUE_USES
157 #define EPILOGUE_USES(REGNO) 0
160 #define EH_USES(REGNO) 0
163 #ifdef HAVE_conditional_execution
164 #ifndef REVERSE_CONDEXEC_PREDICATES_P
165 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) \
166 (GET_CODE ((x)) == reversed_comparison_code ((y), NULL))
170 /* This is the maximum number of times we process any given block if the
171 latest loop depth count is smaller than this number. Only used for the
172 failure strategy to avoid infinite loops in calculate_global_regs_live. */
173 #define MAX_LIVENESS_ROUNDS 20
175 /* Nonzero if the second flow pass has completed. */
178 /* Maximum register number used in this function, plus one. */
182 /* Indexed by n, giving various register information */
184 VEC(reg_info_p
,heap
) *reg_n_info
;
186 /* Regset of regs live when calls to `setjmp'-like functions happen. */
187 /* ??? Does this exist only for the setjmp-clobbered warning message? */
189 static regset regs_live_at_setjmp
;
191 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
192 that have to go in the same hard reg.
193 The first two regs in the list are a pair, and the next two
194 are another pair, etc. */
197 /* Set of registers that may be eliminable. These are handled specially
198 in updating regs_ever_live. */
200 static HARD_REG_SET elim_reg_set
;
202 /* Holds information for tracking conditional register life information. */
203 struct reg_cond_life_info
205 /* A boolean expression of conditions under which a register is dead. */
207 /* Conditions under which a register is dead at the basic block end. */
210 /* A boolean expression of conditions under which a register has been
214 /* ??? Could store mask of bytes that are dead, so that we could finally
215 track lifetimes of multi-word registers accessed via subregs. */
218 /* For use in communicating between propagate_block and its subroutines.
219 Holds all information needed to compute life and def-use information. */
221 struct propagate_block_info
223 /* The basic block we're considering. */
226 /* Bit N is set if register N is conditionally or unconditionally live. */
229 /* Bit N is set if register N is set this insn. */
232 /* Element N is the next insn that uses (hard or pseudo) register N
233 within the current basic block; or zero, if there is no such insn. */
236 /* Contains a list of all the MEMs we are tracking for dead store
240 /* If non-null, record the set of registers set unconditionally in the
244 /* If non-null, record the set of registers set conditionally in the
246 regset cond_local_set
;
248 #ifdef HAVE_conditional_execution
249 /* Indexed by register number, holds a reg_cond_life_info for each
250 register that is not unconditionally live or dead. */
251 splay_tree reg_cond_dead
;
253 /* Bit N is set if register N is in an expression in reg_cond_dead. */
257 /* The length of mem_set_list. */
258 int mem_set_list_len
;
260 /* Nonzero if the value of CC0 is live. */
263 /* Flags controlling the set of information propagate_block collects. */
265 /* Index of instruction being processed. */
269 /* Number of dead insns removed. */
272 /* When PROP_REG_INFO set, array contains pbi->insn_num of instruction
273 where given register died. When the register is marked alive, we use the
274 information to compute amount of instructions life range cross.
275 (remember, we are walking backward). This can be computed as current
276 pbi->insn_num - reg_deaths[regno].
277 At the end of processing each basic block, the remaining live registers
278 are inspected and live ranges are increased same way so liverange of global
279 registers are computed correctly.
281 The array is maintained clear for dead registers, so it can be safely reused
282 for next basic block without expensive memset of the whole array after
283 reseting pbi->insn_num to 0. */
285 static int *reg_deaths
;
287 /* Forward declarations */
288 static int verify_wide_reg_1 (rtx
*, void *);
289 static void verify_wide_reg (int, basic_block
);
290 static void verify_local_live_at_start (regset
, basic_block
);
291 static void notice_stack_pointer_modification_1 (rtx
, rtx
, void *);
292 static void notice_stack_pointer_modification (void);
293 static void mark_reg (rtx
, void *);
294 static void mark_regs_live_at_end (regset
);
295 static void calculate_global_regs_live (sbitmap
, sbitmap
, int);
296 static void propagate_block_delete_insn (rtx
);
297 static rtx
propagate_block_delete_libcall (rtx
, rtx
);
298 static int insn_dead_p (struct propagate_block_info
*, rtx
, int, rtx
);
299 static int libcall_dead_p (struct propagate_block_info
*, rtx
, rtx
);
300 static void mark_set_regs (struct propagate_block_info
*, rtx
, rtx
);
301 static void mark_set_1 (struct propagate_block_info
*, enum rtx_code
, rtx
,
303 static int find_regno_partial (rtx
*, void *);
305 #ifdef HAVE_conditional_execution
306 static int mark_regno_cond_dead (struct propagate_block_info
*, int, rtx
);
307 static void free_reg_cond_life_info (splay_tree_value
);
308 static int flush_reg_cond_reg_1 (splay_tree_node
, void *);
309 static void flush_reg_cond_reg (struct propagate_block_info
*, int);
310 static rtx
elim_reg_cond (rtx
, unsigned int);
311 static rtx
ior_reg_cond (rtx
, rtx
, int);
312 static rtx
not_reg_cond (rtx
);
313 static rtx
and_reg_cond (rtx
, rtx
, int);
316 static void attempt_auto_inc (struct propagate_block_info
*, rtx
, rtx
, rtx
,
318 static void find_auto_inc (struct propagate_block_info
*, rtx
, rtx
);
319 static int try_pre_increment_1 (struct propagate_block_info
*, rtx
);
320 static int try_pre_increment (rtx
, rtx
, HOST_WIDE_INT
);
322 static void mark_used_reg (struct propagate_block_info
*, rtx
, rtx
, rtx
);
323 static void mark_used_regs (struct propagate_block_info
*, rtx
, rtx
, rtx
);
324 void debug_flow_info (void);
325 static void add_to_mem_set_list (struct propagate_block_info
*, rtx
);
326 static int invalidate_mems_from_autoinc (rtx
*, void *);
327 static void invalidate_mems_from_set (struct propagate_block_info
*, rtx
);
328 static void clear_log_links (sbitmap
);
329 static int count_or_remove_death_notes_bb (basic_block
, int);
330 static void allocate_bb_life_data (void);
332 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
333 note associated with the BLOCK. */
336 first_insn_after_basic_block_note (basic_block block
)
340 /* Get the first instruction in the block. */
341 insn
= BB_HEAD (block
);
343 if (insn
== NULL_RTX
)
346 insn
= NEXT_INSN (insn
);
347 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
349 return NEXT_INSN (insn
);
352 /* Perform data flow analysis for the whole control flow graph.
353 FLAGS is a set of PROP_* flags to be used in accumulating flow info. */
356 life_analysis (int flags
)
358 #ifdef ELIMINABLE_REGS
360 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
363 /* Record which registers will be eliminated. We use this in
366 CLEAR_HARD_REG_SET (elim_reg_set
);
368 #ifdef ELIMINABLE_REGS
369 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
370 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
372 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
376 #ifdef CANNOT_CHANGE_MODE_CLASS
377 if (flags
& PROP_REG_INFO
)
378 init_subregs_of_mode ();
382 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
384 /* The post-reload life analysis have (on a global basis) the same
385 registers live as was computed by reload itself. elimination
386 Otherwise offsets and such may be incorrect.
388 Reload will make some registers as live even though they do not
391 We don't want to create new auto-incs after reload, since they
392 are unlikely to be useful and can cause problems with shared
394 if (reload_completed
)
395 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
397 /* We want alias analysis information for local dead store elimination. */
398 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
399 init_alias_analysis ();
401 /* Always remove no-op moves. Do this before other processing so
402 that we don't have to keep re-scanning them. */
403 delete_noop_moves ();
405 /* Some targets can emit simpler epilogues if they know that sp was
406 not ever modified during the function. After reload, of course,
407 we've already emitted the epilogue so there's no sense searching. */
408 if (! reload_completed
)
409 notice_stack_pointer_modification ();
411 /* Allocate and zero out data structures that will record the
412 data from lifetime analysis. */
413 allocate_reg_life_data ();
414 allocate_bb_life_data ();
416 /* Find the set of registers live on function exit. */
417 mark_regs_live_at_end (EXIT_BLOCK_PTR
->il
.rtl
->global_live_at_start
);
419 /* "Update" life info from zero. It'd be nice to begin the
420 relaxation with just the exit and noreturn blocks, but that set
421 is not immediately handy. */
423 if (flags
& PROP_REG_INFO
)
425 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
426 memset (regs_asm_clobbered
, 0, sizeof (regs_asm_clobbered
));
428 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
436 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
437 end_alias_analysis ();
440 dump_flow_info (dump_file
, dump_flags
);
442 /* Removing dead insns should have made jumptables really dead. */
443 delete_dead_jumptables ();
446 /* A subroutine of verify_wide_reg, called through for_each_rtx.
447 Search for REGNO. If found, return 2 if it is not wider than
451 verify_wide_reg_1 (rtx
*px
, void *pregno
)
454 unsigned int regno
= *(int *) pregno
;
456 if (REG_P (x
) && REGNO (x
) == regno
)
458 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
465 /* A subroutine of verify_local_live_at_start. Search through insns
466 of BB looking for register REGNO. */
469 verify_wide_reg (int regno
, basic_block bb
)
471 rtx head
= BB_HEAD (bb
), end
= BB_END (bb
);
477 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
485 head
= NEXT_INSN (head
);
489 fprintf (dump_file
, "Register %d died unexpectedly.\n", regno
);
490 dump_bb (bb
, dump_file
, 0);
492 internal_error ("internal consistency failure");
495 /* A subroutine of update_life_info. Verify that there are no untoward
496 changes in live_at_start during a local update. */
499 verify_local_live_at_start (regset new_live_at_start
, basic_block bb
)
501 if (reload_completed
)
503 /* After reload, there are no pseudos, nor subregs of multi-word
504 registers. The regsets should exactly match. */
505 if (! REG_SET_EQUAL_P (new_live_at_start
,
506 bb
->il
.rtl
->global_live_at_start
))
511 "live_at_start mismatch in bb %d, aborting\nNew:\n",
513 debug_bitmap_file (dump_file
, new_live_at_start
);
514 fputs ("Old:\n", dump_file
);
515 dump_bb (bb
, dump_file
, 0);
517 internal_error ("internal consistency failure");
523 reg_set_iterator rsi
;
525 /* Find the set of changed registers. */
526 XOR_REG_SET (new_live_at_start
, bb
->il
.rtl
->global_live_at_start
);
528 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
, rsi
)
530 /* No registers should die. */
531 if (REGNO_REG_SET_P (bb
->il
.rtl
->global_live_at_start
, i
))
536 "Register %d died unexpectedly.\n", i
);
537 dump_bb (bb
, dump_file
, 0);
539 internal_error ("internal consistency failure");
541 /* Verify that the now-live register is wider than word_mode. */
542 verify_wide_reg (i
, bb
);
547 /* Updates life information starting with the basic blocks set in BLOCKS.
548 If BLOCKS is null, consider it to be the universal set.
550 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholing,
551 we are only expecting local modifications to basic blocks. If we find
552 extra registers live at the beginning of a block, then we either killed
553 useful data, or we have a broken split that wants data not provided.
554 If we find registers removed from live_at_start, that means we have
555 a broken peephole that is killing a register it shouldn't.
557 ??? This is not true in one situation -- when a pre-reload splitter
558 generates subregs of a multi-word pseudo, current life analysis will
559 lose the kill. So we _can_ have a pseudo go live. How irritating.
561 It is also not true when a peephole decides that it doesn't need one
562 or more of the inputs.
564 Including PROP_REG_INFO does not properly refresh regs_ever_live
565 unless the caller resets it to zero. */
568 update_life_info (sbitmap blocks
, enum update_life_extent extent
,
573 int stabilized_prop_flags
= prop_flags
;
576 tmp
= ALLOC_REG_SET (®_obstack
);
579 if ((prop_flags
& PROP_REG_INFO
) && !reg_deaths
)
580 reg_deaths
= XCNEWVEC (int, max_regno
);
582 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
583 ? TV_LIFE_UPDATE
: TV_LIFE
);
585 /* Changes to the CFG are only allowed when
586 doing a global update for the entire CFG. */
587 gcc_assert (!(prop_flags
& PROP_ALLOW_CFG_CHANGES
)
588 || (extent
!= UPDATE_LIFE_LOCAL
&& !blocks
));
590 /* For a global update, we go through the relaxation process again. */
591 if (extent
!= UPDATE_LIFE_LOCAL
)
597 calculate_global_regs_live (blocks
, blocks
,
598 prop_flags
& (PROP_SCAN_DEAD_CODE
599 | PROP_SCAN_DEAD_STORES
600 | PROP_ALLOW_CFG_CHANGES
));
602 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
603 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
606 /* Removing dead code may allow the CFG to be simplified which
607 in turn may allow for further dead code detection / removal. */
608 FOR_EACH_BB_REVERSE (bb
)
610 COPY_REG_SET (tmp
, bb
->il
.rtl
->global_live_at_end
);
611 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
612 prop_flags
& (PROP_SCAN_DEAD_CODE
613 | PROP_SCAN_DEAD_STORES
614 | PROP_KILL_DEAD_CODE
));
617 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
618 subsequent propagate_block calls, since removing or acting as
619 removing dead code can affect global register liveness, which
620 is supposed to be finalized for this call after this loop. */
621 stabilized_prop_flags
622 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
623 | PROP_KILL_DEAD_CODE
);
628 /* We repeat regardless of what cleanup_cfg says. If there were
629 instructions deleted above, that might have been only a
630 partial improvement (see PARAM_MAX_FLOW_MEMORY_LOCATIONS usage).
631 Further improvement may be possible. */
632 cleanup_cfg (CLEANUP_EXPENSIVE
);
634 /* Zap the life information from the last round. If we don't
635 do this, we can wind up with registers that no longer appear
636 in the code being marked live at entry. */
639 CLEAR_REG_SET (bb
->il
.rtl
->global_live_at_start
);
640 CLEAR_REG_SET (bb
->il
.rtl
->global_live_at_end
);
644 /* If asked, remove notes from the blocks we'll update. */
645 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
646 count_or_remove_death_notes (blocks
,
647 prop_flags
& PROP_POST_REGSTACK
? -1 : 1);
651 /* FIXME: This can go when the dataflow branch has been merged in. */
652 /* For a local update, if we are creating new REG_DEAD notes, then we
653 must delete the old ones first to avoid conflicts if they are
655 if (prop_flags
& PROP_DEATH_NOTES
)
656 count_or_remove_death_notes (blocks
,
657 prop_flags
& PROP_POST_REGSTACK
? -1 : 1);
661 /* Clear log links in case we are asked to (re)compute them. */
662 if (prop_flags
& PROP_LOG_LINKS
)
663 clear_log_links (blocks
);
667 sbitmap_iterator sbi
;
669 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
, sbi
)
671 bb
= BASIC_BLOCK (i
);
674 /* The bitmap may be flawed in that one of the basic
675 blocks may have been deleted before you get here. */
676 COPY_REG_SET (tmp
, bb
->il
.rtl
->global_live_at_end
);
677 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
679 if (extent
== UPDATE_LIFE_LOCAL
)
680 verify_local_live_at_start (tmp
, bb
);
686 FOR_EACH_BB_REVERSE (bb
)
688 COPY_REG_SET (tmp
, bb
->il
.rtl
->global_live_at_end
);
690 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
692 if (extent
== UPDATE_LIFE_LOCAL
)
693 verify_local_live_at_start (tmp
, bb
);
699 if (prop_flags
& PROP_REG_INFO
)
701 reg_set_iterator rsi
;
703 /* The only pseudos that are live at the beginning of the function
704 are those that were not set anywhere in the function. local-alloc
705 doesn't know how to handle these correctly, so mark them as not
706 local to any one basic block. */
707 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->il
.rtl
->global_live_at_end
,
708 FIRST_PSEUDO_REGISTER
, i
, rsi
)
709 REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
;
711 /* We have a problem with any pseudoreg that lives across the setjmp.
712 ANSI says that if a user variable does not change in value between
713 the setjmp and the longjmp, then the longjmp preserves it. This
714 includes longjmp from a place where the pseudo appears dead.
715 (In principle, the value still exists if it is in scope.)
716 If the pseudo goes in a hard reg, some other value may occupy
717 that hard reg where this pseudo is dead, thus clobbering the pseudo.
718 Conclusion: such a pseudo must not go in a hard reg. */
719 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
720 FIRST_PSEUDO_REGISTER
, i
, rsi
)
722 if (regno_reg_rtx
[i
] != 0)
724 REG_LIVE_LENGTH (i
) = -1;
725 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
734 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
735 ? TV_LIFE_UPDATE
: TV_LIFE
);
736 if (ndead
&& dump_file
)
737 fprintf (dump_file
, "deleted %i dead insns\n", ndead
);
741 /* Update life information in all blocks where BB_DIRTY is set. */
744 update_life_info_in_dirty_blocks (enum update_life_extent extent
, int prop_flags
)
746 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
751 sbitmap_zero (update_life_blocks
);
754 if (bb
->flags
& BB_DIRTY
)
756 SET_BIT (update_life_blocks
, bb
->index
);
762 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
764 sbitmap_free (update_life_blocks
);
768 /* Free the variables allocated by find_basic_blocks. */
771 free_basic_block_vars (void)
773 if (basic_block_info
)
776 basic_block_info
= NULL
;
779 last_basic_block
= 0;
782 label_to_block_map
= NULL
;
784 ENTRY_BLOCK_PTR
->aux
= NULL
;
785 ENTRY_BLOCK_PTR
->il
.rtl
->global_live_at_end
= NULL
;
786 EXIT_BLOCK_PTR
->aux
= NULL
;
787 EXIT_BLOCK_PTR
->il
.rtl
->global_live_at_start
= NULL
;
790 /* Delete any insns that copy a register to itself. */
793 delete_noop_moves (void)
801 for (insn
= BB_HEAD (bb
); insn
!= NEXT_INSN (BB_END (bb
)); insn
= next
)
803 next
= NEXT_INSN (insn
);
804 if (INSN_P (insn
) && noop_move_p (insn
))
808 /* If we're about to remove the first insn of a libcall
809 then move the libcall note to the next real insn and
810 update the retval note. */
811 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
812 && XEXP (note
, 0) != insn
)
814 rtx new_libcall_insn
= next_real_insn (insn
);
815 rtx retval_note
= find_reg_note (XEXP (note
, 0),
816 REG_RETVAL
, NULL_RTX
);
817 REG_NOTES (new_libcall_insn
)
818 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
819 REG_NOTES (new_libcall_insn
));
820 XEXP (retval_note
, 0) = new_libcall_insn
;
823 delete_insn_and_edges (insn
);
829 if (nnoops
&& dump_file
)
830 fprintf (dump_file
, "deleted %i noop moves\n", nnoops
);
835 /* Delete any jump tables never referenced. We can't delete them at the
836 time of removing tablejump insn as they are referenced by the preceding
837 insns computing the destination, so we delay deleting and garbagecollect
838 them once life information is computed. */
840 delete_dead_jumptables (void)
844 /* A dead jump table does not belong to any basic block. Scan insns
845 between two adjacent basic blocks. */
850 for (insn
= NEXT_INSN (BB_END (bb
));
851 insn
&& !NOTE_INSN_BASIC_BLOCK_P (insn
);
854 next
= NEXT_INSN (insn
);
856 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
858 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
859 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
861 rtx label
= insn
, jump
= next
;
864 fprintf (dump_file
, "Dead jumptable %i removed\n",
867 next
= NEXT_INSN (next
);
875 /* Determine if the stack pointer is constant over the life of the function.
876 Only useful before prologues have been emitted. */
879 notice_stack_pointer_modification_1 (rtx x
, rtx pat ATTRIBUTE_UNUSED
,
880 void *data ATTRIBUTE_UNUSED
)
882 if (x
== stack_pointer_rtx
883 /* The stack pointer is only modified indirectly as the result
884 of a push until later in flow. See the comments in rtl.texi
885 regarding Embedded Side-Effects on Addresses. */
887 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == RTX_AUTOINC
888 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
889 current_function_sp_is_unchanging
= 0;
893 notice_stack_pointer_modification (void)
898 /* Assume that the stack pointer is unchanging if alloca hasn't
900 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
901 if (! current_function_sp_is_unchanging
)
905 FOR_BB_INSNS (bb
, insn
)
909 /* Check if insn modifies the stack pointer. */
910 note_stores (PATTERN (insn
),
911 notice_stack_pointer_modification_1
,
913 if (! current_function_sp_is_unchanging
)
919 /* Mark a register in SET. Hard registers in large modes get all
920 of their component registers set as well. */
923 mark_reg (rtx reg
, void *xset
)
925 regset set
= (regset
) xset
;
926 int regno
= REGNO (reg
);
928 gcc_assert (GET_MODE (reg
) != BLKmode
);
930 SET_REGNO_REG_SET (set
, regno
);
931 if (regno
< FIRST_PSEUDO_REGISTER
)
933 int n
= hard_regno_nregs
[regno
][GET_MODE (reg
)];
935 SET_REGNO_REG_SET (set
, regno
+ n
);
939 /* Mark those regs which are needed at the end of the function as live
940 at the end of the last basic block. */
943 mark_regs_live_at_end (regset set
)
947 /* If exiting needs the right stack value, consider the stack pointer
948 live at the end of the function. */
949 if ((HAVE_epilogue
&& epilogue_completed
)
950 || ! EXIT_IGNORE_STACK
951 || (! FRAME_POINTER_REQUIRED
952 && ! current_function_calls_alloca
953 && flag_omit_frame_pointer
)
954 || current_function_sp_is_unchanging
)
956 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
959 /* Mark the frame pointer if needed at the end of the function. If
960 we end up eliminating it, it will be removed from the live list
961 of each basic block by reload. */
963 if (! reload_completed
|| frame_pointer_needed
)
965 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
966 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
967 /* If they are different, also mark the hard frame pointer as live. */
968 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
969 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
973 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
974 /* Many architectures have a GP register even without flag_pic.
975 Assume the pic register is not in use, or will be handled by
976 other means, if it is not fixed. */
977 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
978 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
979 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
982 /* Mark all global registers, and all registers used by the epilogue
983 as being live at the end of the function since they may be
984 referenced by our caller. */
985 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
986 if (global_regs
[i
] || EPILOGUE_USES (i
))
987 SET_REGNO_REG_SET (set
, i
);
989 if (HAVE_epilogue
&& epilogue_completed
)
991 /* Mark all call-saved registers that we actually used. */
992 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
993 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
994 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
995 SET_REGNO_REG_SET (set
, i
);
998 #ifdef EH_RETURN_DATA_REGNO
999 /* Mark the registers that will contain data for the handler. */
1000 if (reload_completed
&& current_function_calls_eh_return
)
1003 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1004 if (regno
== INVALID_REGNUM
)
1006 SET_REGNO_REG_SET (set
, regno
);
1009 #ifdef EH_RETURN_STACKADJ_RTX
1010 if ((! HAVE_epilogue
|| ! epilogue_completed
)
1011 && current_function_calls_eh_return
)
1013 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1014 if (tmp
&& REG_P (tmp
))
1015 mark_reg (tmp
, set
);
1018 #ifdef EH_RETURN_HANDLER_RTX
1019 if ((! HAVE_epilogue
|| ! epilogue_completed
)
1020 && current_function_calls_eh_return
)
1022 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1023 if (tmp
&& REG_P (tmp
))
1024 mark_reg (tmp
, set
);
1028 /* Mark function return value. */
1029 diddle_return_value (mark_reg
, set
);
1032 /* Propagate global life info around the graph of basic blocks. Begin
1033 considering blocks with their corresponding bit set in BLOCKS_IN.
1034 If BLOCKS_IN is null, consider it the universal set.
1036 BLOCKS_OUT is set for every block that was changed. */
1039 calculate_global_regs_live (sbitmap blocks_in
, sbitmap blocks_out
, int flags
)
1041 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1042 regset tmp
, new_live_at_end
, invalidated_by_eh_edge
;
1043 regset registers_made_dead
;
1044 bool failure_strategy_required
= false;
1045 int *block_accesses
;
1047 /* The registers that are modified within this in block. */
1050 /* The registers that are conditionally modified within this block.
1051 In other words, regs that are set only as part of a COND_EXEC. */
1052 regset
*cond_local_sets
;
1056 /* Some passes used to forget clear aux field of basic block causing
1057 sick behavior here. */
1058 #ifdef ENABLE_CHECKING
1059 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1060 gcc_assert (!bb
->aux
);
1063 tmp
= ALLOC_REG_SET (®_obstack
);
1064 new_live_at_end
= ALLOC_REG_SET (®_obstack
);
1065 invalidated_by_eh_edge
= ALLOC_REG_SET (®_obstack
);
1066 registers_made_dead
= ALLOC_REG_SET (®_obstack
);
1068 /* Inconveniently, this is only readily available in hard reg set form. */
1069 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1070 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1071 SET_REGNO_REG_SET (invalidated_by_eh_edge
, i
);
1073 /* The exception handling registers die at eh edges. */
1074 #ifdef EH_RETURN_DATA_REGNO
1077 unsigned regno
= EH_RETURN_DATA_REGNO (i
);
1078 if (regno
== INVALID_REGNUM
)
1080 SET_REGNO_REG_SET (invalidated_by_eh_edge
, regno
);
1084 /* Allocate space for the sets of local properties. */
1085 local_sets
= XCNEWVEC (bitmap
, last_basic_block
);
1086 cond_local_sets
= XCNEWVEC (bitmap
, last_basic_block
);
1088 /* Create a worklist. Allocate an extra slot for the `head == tail'
1089 style test for an empty queue doesn't work with a full queue. */
1090 queue
= XNEWVEC (basic_block
, n_basic_blocks
+ 1);
1092 qhead
= qend
= queue
+ n_basic_blocks
;
1094 /* Queue the blocks set in the initial mask. Do this in reverse block
1095 number order so that we are more likely for the first round to do
1096 useful work. We use AUX non-null to flag that the block is queued. */
1100 if (TEST_BIT (blocks_in
, bb
->index
))
1115 block_accesses
= XCNEWVEC (int, last_basic_block
);
1117 /* We clean aux when we remove the initially-enqueued bbs, but we
1118 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1120 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1123 sbitmap_zero (blocks_out
);
1125 /* We work through the queue until there are no more blocks. What
1126 is live at the end of this block is precisely the union of what
1127 is live at the beginning of all its successors. So, we set its
1128 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1129 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1130 this block by walking through the instructions in this block in
1131 reverse order and updating as we go. If that changed
1132 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1133 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1135 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1136 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1137 must either be live at the end of the block, or used within the
1138 block. In the latter case, it will certainly never disappear
1139 from GLOBAL_LIVE_AT_START. In the former case, the register
1140 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1141 for one of the successor blocks. By induction, that cannot
1144 ??? This reasoning doesn't work if we start from non-empty initial
1145 GLOBAL_LIVE_AT_START sets. And there are actually two problems:
1146 1) Updating may not terminate (endless oscillation).
1147 2) Even if it does (and it usually does), the resulting information
1148 may be inaccurate. Consider for example the following case:
1151 while (...) {...} -- 'a' not mentioned at all
1154 If the use of 'a' is deleted between two calculations of liveness
1155 information and the initial sets are not cleared, the information
1156 about a's liveness will get stuck inside the loop and the set will
1157 appear not to be dead.
1159 We do not attempt to solve 2) -- the information is conservatively
1160 correct (i.e. we never claim that something live is dead) and the
1161 amount of optimization opportunities missed due to this problem is
1164 1) is more serious. In order to fix it, we monitor the number of times
1165 each block is processed. Once one of the blocks has been processed more
1166 times than the maximum number of rounds, we use the following strategy:
1167 When a register disappears from one of the sets, we add it to a MAKE_DEAD
1168 set, remove all registers in this set from all GLOBAL_LIVE_AT_* sets and
1169 add the blocks with changed sets into the queue. Thus we are guaranteed
1170 to terminate (the worst case corresponds to all registers in MADE_DEAD,
1171 in which case the original reasoning above is valid), but in general we
1172 only fix up a few offending registers.
1174 The maximum number of rounds for computing liveness is the largest of
1175 MAX_LIVENESS_ROUNDS and the latest loop depth count for this function. */
1177 while (qhead
!= qtail
)
1179 int rescan
, changed
;
1189 /* Should we start using the failure strategy? */
1190 if (bb
!= ENTRY_BLOCK_PTR
)
1192 int max_liveness_rounds
=
1193 MAX (MAX_LIVENESS_ROUNDS
, cfun
->max_loop_depth
);
1195 block_accesses
[bb
->index
]++;
1196 if (block_accesses
[bb
->index
] > max_liveness_rounds
)
1197 failure_strategy_required
= true;
1200 /* Begin by propagating live_at_start from the successor blocks. */
1201 CLEAR_REG_SET (new_live_at_end
);
1203 if (EDGE_COUNT (bb
->succs
) > 0)
1204 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1206 basic_block sb
= e
->dest
;
1208 /* Call-clobbered registers die across exception and
1210 /* ??? Abnormal call edges ignored for the moment, as this gets
1211 confused by sibling call edges, which crashes reg-stack. */
1212 if (e
->flags
& EDGE_EH
)
1213 bitmap_ior_and_compl_into (new_live_at_end
,
1214 sb
->il
.rtl
->global_live_at_start
,
1215 invalidated_by_eh_edge
);
1217 IOR_REG_SET (new_live_at_end
, sb
->il
.rtl
->global_live_at_start
);
1219 /* If a target saves one register in another (instead of on
1220 the stack) the save register will need to be live for EH. */
1221 if (e
->flags
& EDGE_EH
)
1222 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1224 SET_REGNO_REG_SET (new_live_at_end
, i
);
1228 /* This might be a noreturn function that throws. And
1229 even if it isn't, getting the unwind info right helps
1231 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1233 SET_REGNO_REG_SET (new_live_at_end
, i
);
1236 /* The all-important stack pointer must always be live. */
1237 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1239 /* Before reload, there are a few registers that must be forced
1240 live everywhere -- which might not already be the case for
1241 blocks within infinite loops. */
1242 if (! reload_completed
)
1244 /* Any reference to any pseudo before reload is a potential
1245 reference of the frame pointer. */
1246 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1248 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1249 /* Pseudos with argument area equivalences may require
1250 reloading via the argument pointer. */
1251 if (fixed_regs
[ARG_POINTER_REGNUM
])
1252 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1255 /* Any constant, or pseudo with constant equivalences, may
1256 require reloading from memory using the pic register. */
1257 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1258 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1259 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1262 if (bb
== ENTRY_BLOCK_PTR
)
1264 COPY_REG_SET (bb
->il
.rtl
->global_live_at_end
, new_live_at_end
);
1268 /* On our first pass through this block, we'll go ahead and continue.
1269 Recognize first pass by checking if local_set is NULL for this
1270 basic block. On subsequent passes, we get to skip out early if
1271 live_at_end wouldn't have changed. */
1273 if (local_sets
[bb
->index
] == NULL
)
1275 local_sets
[bb
->index
] = ALLOC_REG_SET (®_obstack
);
1276 cond_local_sets
[bb
->index
] = ALLOC_REG_SET (®_obstack
);
1281 /* If any bits were removed from live_at_end, we'll have to
1282 rescan the block. This wouldn't be necessary if we had
1283 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1284 local_live is really dependent on live_at_end. */
1285 rescan
= bitmap_intersect_compl_p (bb
->il
.rtl
->global_live_at_end
,
1290 regset cond_local_set
;
1292 /* If any of the registers in the new live_at_end set are
1293 conditionally set in this basic block, we must rescan.
1294 This is because conditional lifetimes at the end of the
1295 block do not just take the live_at_end set into
1296 account, but also the liveness at the start of each
1297 successor block. We can miss changes in those sets if
1298 we only compare the new live_at_end against the
1300 cond_local_set
= cond_local_sets
[bb
->index
];
1301 rescan
= bitmap_intersect_p (new_live_at_end
, cond_local_set
);
1308 /* Find the set of changed bits. Take this opportunity
1309 to notice that this set is empty and early out. */
1310 bitmap_xor (tmp
, bb
->il
.rtl
->global_live_at_end
, new_live_at_end
);
1311 if (bitmap_empty_p (tmp
))
1314 /* If any of the changed bits overlap with local_sets[bb],
1315 we'll have to rescan the block. */
1316 local_set
= local_sets
[bb
->index
];
1317 rescan
= bitmap_intersect_p (tmp
, local_set
);
1321 /* Let our caller know that BB changed enough to require its
1322 death notes updated. */
1324 SET_BIT (blocks_out
, bb
->index
);
1328 /* Add to live_at_start the set of all registers in
1329 new_live_at_end that aren't in the old live_at_end. */
1331 changed
= bitmap_ior_and_compl_into (bb
->il
.rtl
->global_live_at_start
,
1333 bb
->il
.rtl
->global_live_at_end
);
1334 COPY_REG_SET (bb
->il
.rtl
->global_live_at_end
, new_live_at_end
);
1340 COPY_REG_SET (bb
->il
.rtl
->global_live_at_end
, new_live_at_end
);
1342 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1343 into live_at_start. */
1344 propagate_block (bb
, new_live_at_end
,
1345 local_sets
[bb
->index
],
1346 cond_local_sets
[bb
->index
],
1349 /* If live_at start didn't change, no need to go farther. */
1350 if (REG_SET_EQUAL_P (bb
->il
.rtl
->global_live_at_start
,
1354 if (failure_strategy_required
)
1356 /* Get the list of registers that were removed from the
1357 bb->global_live_at_start set. */
1358 bitmap_and_compl (tmp
, bb
->il
.rtl
->global_live_at_start
,
1360 if (!bitmap_empty_p (tmp
))
1365 /* It should not happen that one of registers we have
1366 removed last time is disappears again before any other
1368 pbb_changed
= bitmap_ior_into (registers_made_dead
, tmp
);
1369 gcc_assert (pbb_changed
);
1371 /* Now remove the registers from all sets. */
1374 pbb_changed
= false;
1377 |= bitmap_and_compl_into
1378 (pbb
->il
.rtl
->global_live_at_start
,
1379 registers_made_dead
);
1381 |= bitmap_and_compl_into
1382 (pbb
->il
.rtl
->global_live_at_end
,
1383 registers_made_dead
);
1387 /* Note the (possible) change. */
1389 SET_BIT (blocks_out
, pbb
->index
);
1391 /* Makes sure to really rescan the block. */
1392 if (local_sets
[pbb
->index
])
1394 FREE_REG_SET (local_sets
[pbb
->index
]);
1395 FREE_REG_SET (cond_local_sets
[pbb
->index
]);
1396 local_sets
[pbb
->index
] = 0;
1399 /* Add it to the queue. */
1400 if (pbb
->aux
== NULL
)
1410 } /* end of failure_strategy_required */
1412 COPY_REG_SET (bb
->il
.rtl
->global_live_at_start
, new_live_at_end
);
1415 /* Queue all predecessors of BB so that we may re-examine
1416 their live_at_end. */
1417 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1419 basic_block pb
= e
->src
;
1421 gcc_assert ((e
->flags
& EDGE_FAKE
) == 0);
1423 if (pb
->aux
== NULL
)
1434 FREE_REG_SET (new_live_at_end
);
1435 FREE_REG_SET (invalidated_by_eh_edge
);
1436 FREE_REG_SET (registers_made_dead
);
1440 sbitmap_iterator sbi
;
1442 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
, sbi
)
1444 basic_block bb
= BASIC_BLOCK (i
);
1445 FREE_REG_SET (local_sets
[bb
->index
]);
1446 FREE_REG_SET (cond_local_sets
[bb
->index
]);
1453 FREE_REG_SET (local_sets
[bb
->index
]);
1454 FREE_REG_SET (cond_local_sets
[bb
->index
]);
1458 free (block_accesses
);
1460 free (cond_local_sets
);
1465 /* This structure is used to pass parameters to and from the
1466 the function find_regno_partial(). It is used to pass in the
1467 register number we are looking, as well as to return any rtx
1471 unsigned regno_to_find
;
1473 } find_regno_partial_param
;
1476 /* Find the rtx for the reg numbers specified in 'data' if it is
1477 part of an expression which only uses part of the register. Return
1478 it in the structure passed in. */
1480 find_regno_partial (rtx
*ptr
, void *data
)
1482 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1483 unsigned reg
= param
->regno_to_find
;
1484 param
->retval
= NULL_RTX
;
1486 if (*ptr
== NULL_RTX
)
1489 switch (GET_CODE (*ptr
))
1493 case STRICT_LOW_PART
:
1494 if (REG_P (XEXP (*ptr
, 0)) && REGNO (XEXP (*ptr
, 0)) == reg
)
1496 param
->retval
= XEXP (*ptr
, 0);
1502 if (REG_P (SUBREG_REG (*ptr
))
1503 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1505 param
->retval
= SUBREG_REG (*ptr
);
1517 /* Process all immediate successors of the entry block looking for pseudo
1518 registers which are live on entry. Find all of those whose first
1519 instance is a partial register reference of some kind, and initialize
1520 them to 0 after the entry block. This will prevent bit sets within
1521 registers whose value is unknown, and may contain some kind of sticky
1522 bits we don't want. */
1525 initialize_uninitialized_subregs (void)
1529 unsigned reg
, did_something
= 0;
1530 find_regno_partial_param param
;
1533 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
1535 basic_block bb
= e
->dest
;
1536 regset map
= bb
->il
.rtl
->global_live_at_start
;
1537 reg_set_iterator rsi
;
1539 EXECUTE_IF_SET_IN_REG_SET (map
, FIRST_PSEUDO_REGISTER
, reg
, rsi
)
1541 int uid
= REGNO_FIRST_UID (reg
);
1544 /* Find an insn which mentions the register we are looking for.
1545 Its preferable to have an instance of the register's rtl since
1546 there may be various flags set which we need to duplicate.
1547 If we can't find it, its probably an automatic whose initial
1548 value doesn't matter, or hopefully something we don't care about. */
1549 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1553 /* Found the insn, now get the REG rtx, if we can. */
1554 param
.regno_to_find
= reg
;
1555 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1556 if (param
.retval
!= NULL_RTX
)
1559 emit_move_insn (param
.retval
,
1560 CONST0_RTX (GET_MODE (param
.retval
)));
1561 insn
= get_insns ();
1563 insert_insn_on_edge (insn
, e
);
1571 commit_edge_insertions ();
1572 return did_something
;
1576 /* Subroutines of life analysis. */
1578 /* Allocate the permanent data structures that represent the results
1579 of life analysis. */
1582 allocate_bb_life_data (void)
1586 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1588 if (bb
->il
.rtl
->global_live_at_start
)
1590 CLEAR_REG_SET (bb
->il
.rtl
->global_live_at_start
);
1591 CLEAR_REG_SET (bb
->il
.rtl
->global_live_at_end
);
1595 bb
->il
.rtl
->global_live_at_start
= ALLOC_REG_SET (®_obstack
);
1596 bb
->il
.rtl
->global_live_at_end
= ALLOC_REG_SET (®_obstack
);
1600 regs_live_at_setjmp
= ALLOC_REG_SET (®_obstack
);
1604 allocate_reg_life_data (void)
1608 max_regno
= max_reg_num ();
1609 gcc_assert (!reg_deaths
);
1610 reg_deaths
= XCNEWVEC (int, max_regno
);
1612 /* Recalculate the register space, in case it has grown. Old style
1613 vector oriented regsets would set regset_{size,bytes} here also. */
1614 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1616 /* Reset all the data we'll collect in propagate_block and its
1618 for (i
= 0; i
< max_regno
; i
++)
1622 REG_N_DEATHS (i
) = 0;
1623 REG_N_CALLS_CROSSED (i
) = 0;
1624 REG_N_THROWING_CALLS_CROSSED (i
) = 0;
1625 REG_LIVE_LENGTH (i
) = 0;
1627 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1631 /* Delete dead instructions for propagate_block. */
1634 propagate_block_delete_insn (rtx insn
)
1636 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1638 /* If the insn referred to a label, and that label was attached to
1639 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1640 pretty much mandatory to delete it, because the ADDR_VEC may be
1641 referencing labels that no longer exist.
1643 INSN may reference a deleted label, particularly when a jump
1644 table has been optimized into a direct jump. There's no
1645 real good way to fix up the reference to the deleted label
1646 when the label is deleted, so we just allow it here. */
1648 if (inote
&& LABEL_P (inote
))
1650 rtx label
= XEXP (inote
, 0);
1653 /* The label may be forced if it has been put in the constant
1654 pool. If that is the only use we must discard the table
1655 jump following it, but not the label itself. */
1656 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1657 && (next
= next_nonnote_insn (label
)) != NULL
1659 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1660 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1662 rtx pat
= PATTERN (next
);
1663 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1664 int len
= XVECLEN (pat
, diff_vec_p
);
1667 for (i
= 0; i
< len
; i
++)
1668 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1670 delete_insn_and_edges (next
);
1675 delete_insn_and_edges (insn
);
1679 /* Delete dead libcalls for propagate_block. Return the insn
1680 before the libcall. */
1683 propagate_block_delete_libcall (rtx insn
, rtx note
)
1685 rtx first
= XEXP (note
, 0);
1686 rtx before
= PREV_INSN (first
);
1688 delete_insn_chain_and_edges (first
, insn
);
1693 /* Update the life-status of regs for one insn. Return the previous insn. */
1696 propagate_one_insn (struct propagate_block_info
*pbi
, rtx insn
)
1698 rtx prev
= PREV_INSN (insn
);
1699 int flags
= pbi
->flags
;
1700 int insn_is_dead
= 0;
1701 int libcall_is_dead
= 0;
1705 if (! INSN_P (insn
))
1708 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1709 if (flags
& PROP_SCAN_DEAD_CODE
)
1711 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1712 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1713 && libcall_dead_p (pbi
, note
, insn
));
1716 /* If an instruction consists of just dead store(s) on final pass,
1718 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1720 /* If we're trying to delete a prologue or epilogue instruction
1721 that isn't flagged as possibly being dead, something is wrong.
1722 But if we are keeping the stack pointer depressed, we might well
1723 be deleting insns that are used to compute the amount to update
1724 it by, so they are fine. */
1725 if (reload_completed
1726 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1727 && (TYPE_RETURNS_STACK_DEPRESSED
1728 (TREE_TYPE (current_function_decl
))))
1729 && (((HAVE_epilogue
|| HAVE_prologue
)
1730 && prologue_epilogue_contains (insn
))
1731 || (HAVE_sibcall_epilogue
1732 && sibcall_epilogue_contains (insn
)))
1733 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1734 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1736 /* Record sets. Do this even for dead instructions, since they
1737 would have killed the values if they hadn't been deleted. To
1738 be consistent, we also have to emit a clobber when we delete
1739 an insn that clobbers a live register. */
1740 pbi
->flags
|= PROP_DEAD_INSN
;
1741 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1742 pbi
->flags
&= ~PROP_DEAD_INSN
;
1744 /* CC0 is now known to be dead. Either this insn used it,
1745 in which case it doesn't anymore, or clobbered it,
1746 so the next insn can't use it. */
1749 if (libcall_is_dead
)
1750 prev
= propagate_block_delete_libcall (insn
, note
);
1754 /* If INSN contains a RETVAL note and is dead, but the libcall
1755 as a whole is not dead, then we want to remove INSN, but
1756 not the whole libcall sequence.
1758 However, we need to also remove the dangling REG_LIBCALL
1759 note so that we do not have mis-matched LIBCALL/RETVAL
1760 notes. In theory we could find a new location for the
1761 REG_RETVAL note, but it hardly seems worth the effort.
1763 NOTE at this point will be the RETVAL note if it exists. */
1769 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1770 remove_note (XEXP (note
, 0), libcall_note
);
1773 /* Similarly if INSN contains a LIBCALL note, remove the
1774 dangling REG_RETVAL note. */
1775 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
1781 = find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
1782 remove_note (XEXP (note
, 0), retval_note
);
1785 /* Now delete INSN. */
1786 propagate_block_delete_insn (insn
);
1792 /* See if this is an increment or decrement that can be merged into
1793 a following memory address. */
1796 rtx x
= single_set (insn
);
1798 /* Does this instruction increment or decrement a register? */
1799 if ((flags
& PROP_AUTOINC
)
1801 && REG_P (SET_DEST (x
))
1802 && (GET_CODE (SET_SRC (x
)) == PLUS
1803 || GET_CODE (SET_SRC (x
)) == MINUS
)
1804 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1805 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1806 /* Ok, look for a following memory ref we can combine with.
1807 If one is found, change the memory ref to a PRE_INC
1808 or PRE_DEC, cancel this insn, and return 1.
1809 Return 0 if nothing has been done. */
1810 && try_pre_increment_1 (pbi
, insn
))
1813 #endif /* AUTO_INC_DEC */
1815 CLEAR_REG_SET (pbi
->new_set
);
1817 /* If this is not the final pass, and this insn is copying the value of
1818 a library call and it's dead, don't scan the insns that perform the
1819 library call, so that the call's arguments are not marked live. */
1820 if (libcall_is_dead
)
1822 /* Record the death of the dest reg. */
1823 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1825 insn
= XEXP (note
, 0);
1826 return PREV_INSN (insn
);
1828 else if (GET_CODE (PATTERN (insn
)) == SET
1829 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1830 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1831 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1832 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1834 /* We have an insn to pop a constant amount off the stack.
1835 (Such insns use PLUS regardless of the direction of the stack,
1836 and any insn to adjust the stack by a constant is always a pop
1838 These insns, if not dead stores, have no effect on life, though
1839 they do have an effect on the memory stores we are tracking. */
1840 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1841 /* Still, we need to update local_set, lest ifcvt.c:dead_or_predicable
1842 concludes that the stack pointer is not modified. */
1843 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1847 /* Any regs live at the time of a call instruction must not go
1848 in a register clobbered by calls. Find all regs now live and
1849 record this for them. */
1851 if (CALL_P (insn
) && (flags
& PROP_REG_INFO
))
1853 reg_set_iterator rsi
;
1854 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
, rsi
)
1855 REG_N_CALLS_CROSSED (i
)++;
1856 if (can_throw_internal (insn
))
1857 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
, rsi
)
1858 REG_N_THROWING_CALLS_CROSSED (i
)++;
1861 /* Record sets. Do this even for dead instructions, since they
1862 would have killed the values if they hadn't been deleted. */
1863 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1873 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1874 cond
= COND_EXEC_TEST (PATTERN (insn
));
1876 /* Non-constant calls clobber memory, constant calls do not
1877 clobber memory, though they may clobber outgoing arguments
1879 if (! CONST_OR_PURE_CALL_P (insn
))
1881 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1882 pbi
->mem_set_list_len
= 0;
1885 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1887 /* There may be extra registers to be clobbered. */
1888 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1890 note
= XEXP (note
, 1))
1891 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1892 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1893 cond
, insn
, pbi
->flags
);
1895 /* Calls change all call-used and global registers; sibcalls do not
1896 clobber anything that must be preserved at end-of-function,
1897 except for return values. */
1899 sibcall_p
= SIBLING_CALL_P (insn
);
1900 live_at_end
= EXIT_BLOCK_PTR
->il
.rtl
->global_live_at_start
;
1901 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1902 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
)
1904 && REGNO_REG_SET_P (live_at_end
, i
)
1905 && ! refers_to_regno_p (i
, i
+1,
1906 current_function_return_rtx
,
1909 enum rtx_code code
= global_regs
[i
] ? SET
: CLOBBER
;
1910 /* We do not want REG_UNUSED notes for these registers. */
1911 mark_set_1 (pbi
, code
, regno_reg_rtx
[i
], cond
, insn
,
1912 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1916 /* If an insn doesn't use CC0, it becomes dead since we assume
1917 that every insn clobbers it. So show it dead here;
1918 mark_used_regs will set it live if it is referenced. */
1923 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1925 /* Sometimes we may have inserted something before INSN (such as a move)
1926 when we make an auto-inc. So ensure we will scan those insns. */
1928 prev
= PREV_INSN (insn
);
1931 if (! insn_is_dead
&& CALL_P (insn
))
1937 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1938 cond
= COND_EXEC_TEST (PATTERN (insn
));
1940 /* Calls use their arguments, and may clobber memory which
1941 address involves some register. */
1942 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1944 note
= XEXP (note
, 1))
1945 /* We find USE or CLOBBER entities in a FUNCTION_USAGE list: both
1946 of which mark_used_regs knows how to handle. */
1947 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0), cond
, insn
);
1949 /* The stack ptr is used (honorarily) by a CALL insn. */
1950 if ((flags
& PROP_REG_INFO
)
1951 && !REGNO_REG_SET_P (pbi
->reg_live
, STACK_POINTER_REGNUM
))
1952 reg_deaths
[STACK_POINTER_REGNUM
] = pbi
->insn_num
;
1953 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1955 /* Calls may also reference any of the global registers,
1956 so they are made live. */
1957 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1959 mark_used_reg (pbi
, regno_reg_rtx
[i
], cond
, insn
);
1968 /* Initialize a propagate_block_info struct for public consumption.
1969 Note that the structure itself is opaque to this file, but that
1970 the user can use the regsets provided here. */
1972 struct propagate_block_info
*
1973 init_propagate_block_info (basic_block bb
, regset live
, regset local_set
,
1974 regset cond_local_set
, int flags
)
1976 struct propagate_block_info
*pbi
= XNEW (struct propagate_block_info
);
1979 pbi
->reg_live
= live
;
1980 pbi
->mem_set_list
= NULL_RTX
;
1981 pbi
->mem_set_list_len
= 0;
1982 pbi
->local_set
= local_set
;
1983 pbi
->cond_local_set
= cond_local_set
;
1988 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1989 pbi
->reg_next_use
= XCNEWVEC (rtx
, max_reg_num ());
1991 pbi
->reg_next_use
= NULL
;
1993 pbi
->new_set
= BITMAP_ALLOC (NULL
);
1995 #ifdef HAVE_conditional_execution
1996 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1997 free_reg_cond_life_info
);
1998 pbi
->reg_cond_reg
= BITMAP_ALLOC (NULL
);
2000 /* If this block ends in a conditional branch, for each register
2001 live from one side of the branch and not the other, record the
2002 register as conditionally dead. */
2003 if (JUMP_P (BB_END (bb
))
2004 && any_condjump_p (BB_END (bb
)))
2006 regset diff
= ALLOC_REG_SET (®_obstack
);
2007 basic_block bb_true
, bb_false
;
2010 /* Identify the successor blocks. */
2011 bb_true
= EDGE_SUCC (bb
, 0)->dest
;
2012 if (!single_succ_p (bb
))
2014 bb_false
= EDGE_SUCC (bb
, 1)->dest
;
2016 if (EDGE_SUCC (bb
, 0)->flags
& EDGE_FALLTHRU
)
2018 basic_block t
= bb_false
;
2023 gcc_assert (EDGE_SUCC (bb
, 1)->flags
& EDGE_FALLTHRU
);
2027 /* This can happen with a conditional jump to the next insn. */
2028 gcc_assert (JUMP_LABEL (BB_END (bb
)) == BB_HEAD (bb_true
));
2030 /* Simplest way to do nothing. */
2034 /* Compute which register lead different lives in the successors. */
2035 bitmap_xor (diff
, bb_true
->il
.rtl
->global_live_at_start
,
2036 bb_false
->il
.rtl
->global_live_at_start
);
2038 if (!bitmap_empty_p (diff
))
2040 /* Extract the condition from the branch. */
2041 rtx set_src
= SET_SRC (pc_set (BB_END (bb
)));
2042 rtx cond_true
= XEXP (set_src
, 0);
2043 rtx reg
= XEXP (cond_true
, 0);
2044 enum rtx_code inv_cond
;
2046 if (GET_CODE (reg
) == SUBREG
)
2047 reg
= SUBREG_REG (reg
);
2049 /* We can only track conditional lifetimes if the condition is
2050 in the form of a reversible comparison of a register against
2051 zero. If the condition is more complex than that, then it is
2052 safe not to record any information. */
2053 inv_cond
= reversed_comparison_code (cond_true
, BB_END (bb
));
2054 if (inv_cond
!= UNKNOWN
2056 && XEXP (cond_true
, 1) == const0_rtx
)
2059 = gen_rtx_fmt_ee (inv_cond
,
2060 GET_MODE (cond_true
), XEXP (cond_true
, 0),
2061 XEXP (cond_true
, 1));
2062 reg_set_iterator rsi
;
2064 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
2067 cond_false
= cond_true
;
2071 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
2073 /* For each such register, mark it conditionally dead. */
2074 EXECUTE_IF_SET_IN_REG_SET (diff
, 0, i
, rsi
)
2076 struct reg_cond_life_info
*rcli
;
2079 rcli
= XNEW (struct reg_cond_life_info
);
2081 if (REGNO_REG_SET_P (bb_true
->il
.rtl
->global_live_at_start
,
2086 rcli
->condition
= cond
;
2087 rcli
->stores
= const0_rtx
;
2088 rcli
->orig_condition
= cond
;
2090 splay_tree_insert (pbi
->reg_cond_dead
, i
,
2091 (splay_tree_value
) rcli
);
2096 FREE_REG_SET (diff
);
2100 /* If this block has no successors, any stores to the frame that aren't
2101 used later in the block are dead. So make a pass over the block
2102 recording any such that are made and show them dead at the end. We do
2103 a very conservative and simple job here. */
2105 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
2106 && (TYPE_RETURNS_STACK_DEPRESSED
2107 (TREE_TYPE (current_function_decl
))))
2108 && (flags
& PROP_SCAN_DEAD_STORES
)
2109 && (EDGE_COUNT (bb
->succs
) == 0
2110 || (single_succ_p (bb
)
2111 && single_succ (bb
) == EXIT_BLOCK_PTR
2112 && ! current_function_calls_eh_return
)))
2115 for (insn
= BB_END (bb
); insn
!= BB_HEAD (bb
); insn
= PREV_INSN (insn
))
2116 if (NONJUMP_INSN_P (insn
)
2117 && (set
= single_set (insn
))
2118 && MEM_P (SET_DEST (set
)))
2120 rtx mem
= SET_DEST (set
);
2121 rtx canon_mem
= canon_rtx (mem
);
2123 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
2124 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
2125 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
2126 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
2127 add_to_mem_set_list (pbi
, canon_mem
);
2134 /* Release a propagate_block_info struct. */
2137 free_propagate_block_info (struct propagate_block_info
*pbi
)
2139 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2141 BITMAP_FREE (pbi
->new_set
);
2143 #ifdef HAVE_conditional_execution
2144 splay_tree_delete (pbi
->reg_cond_dead
);
2145 BITMAP_FREE (pbi
->reg_cond_reg
);
2148 if (pbi
->flags
& PROP_REG_INFO
)
2150 int num
= pbi
->insn_num
;
2152 reg_set_iterator rsi
;
2154 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
, rsi
)
2156 REG_LIVE_LENGTH (i
) += num
- reg_deaths
[i
];
2160 if (pbi
->reg_next_use
)
2161 free (pbi
->reg_next_use
);
2166 /* Compute the registers live at the beginning of a basic block BB from
2167 those live at the end.
2169 When called, REG_LIVE contains those live at the end. On return, it
2170 contains those live at the beginning.
2172 LOCAL_SET, if non-null, will be set with all registers killed
2173 unconditionally by this basic block.
2174 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2175 killed conditionally by this basic block. If there is any unconditional
2176 set of a register, then the corresponding bit will be set in LOCAL_SET
2177 and cleared in COND_LOCAL_SET.
2178 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2179 case, the resulting set will be equal to the union of the two sets that
2180 would otherwise be computed.
2182 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2185 propagate_block (basic_block bb
, regset live
, regset local_set
,
2186 regset cond_local_set
, int flags
)
2188 struct propagate_block_info
*pbi
;
2192 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2194 if (flags
& PROP_REG_INFO
)
2197 reg_set_iterator rsi
;
2199 /* Process the regs live at the end of the block.
2200 Mark them as not local to any one basic block. */
2201 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
, rsi
)
2202 REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
;
2205 /* Scan the block an insn at a time from end to beginning. */
2208 for (insn
= BB_END (bb
); ; insn
= prev
)
2210 /* If this is a call to `setjmp' et al, warn if any
2211 non-volatile datum is live. */
2212 if ((flags
& PROP_REG_INFO
)
2214 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2215 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2217 prev
= propagate_one_insn (pbi
, insn
);
2219 changed
|= insn
!= get_insns ();
2221 changed
|= NEXT_INSN (prev
) != insn
;
2223 if (insn
== BB_HEAD (bb
))
2227 #ifdef EH_RETURN_DATA_REGNO
2228 if (bb_has_eh_pred (bb
))
2233 unsigned regno
= EH_RETURN_DATA_REGNO (i
);
2234 if (regno
== INVALID_REGNUM
)
2238 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, regno
);
2239 SET_REGNO_REG_SET (pbi
->local_set
, regno
);
2241 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2242 SET_REGNO_REG_SET (pbi
->new_set
, regno
);
2244 regs_ever_live
[regno
] = 1;
2249 free_propagate_block_info (pbi
);
2254 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2255 (SET expressions whose destinations are registers dead after the insn).
2256 NEEDED is the regset that says which regs are alive after the insn.
2258 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2260 If X is the entire body of an insn, NOTES contains the reg notes
2261 pertaining to the insn. */
2264 insn_dead_p (struct propagate_block_info
*pbi
, rtx x
, int call_ok
,
2265 rtx notes ATTRIBUTE_UNUSED
)
2267 enum rtx_code code
= GET_CODE (x
);
2269 /* Don't eliminate insns that may trap. */
2270 if (flag_non_call_exceptions
&& may_trap_p (x
))
2274 /* As flow is invoked after combine, we must take existing AUTO_INC
2275 expressions into account. */
2276 for (; notes
; notes
= XEXP (notes
, 1))
2278 if (REG_NOTE_KIND (notes
) == REG_INC
)
2280 int regno
= REGNO (XEXP (notes
, 0));
2282 /* Don't delete insns to set global regs. */
2283 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2284 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2290 /* If setting something that's a reg or part of one,
2291 see if that register's altered value will be live. */
2295 rtx r
= SET_DEST (x
);
2298 if (GET_CODE (r
) == CC0
)
2299 return ! pbi
->cc0_live
;
2302 /* A SET that is a subroutine call cannot be dead. */
2303 if (GET_CODE (SET_SRC (x
)) == CALL
)
2309 /* Don't eliminate loads from volatile memory or volatile asms. */
2310 else if (volatile_refs_p (SET_SRC (x
)))
2317 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2320 canon_r
= canon_rtx (r
);
2322 /* Walk the set of memory locations we are currently tracking
2323 and see if one is an identical match to this memory location.
2324 If so, this memory write is dead (remember, we're walking
2325 backwards from the end of the block to the start). Since
2326 rtx_equal_p does not check the alias set or flags, we also
2327 must have the potential for them to conflict (anti_dependence). */
2328 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2329 if (anti_dependence (r
, XEXP (temp
, 0)))
2331 rtx mem
= XEXP (temp
, 0);
2333 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2334 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2335 <= GET_MODE_SIZE (GET_MODE (mem
))))
2339 /* Check if memory reference matches an auto increment. Only
2340 post increment/decrement or modify are valid. */
2341 if (GET_MODE (mem
) == GET_MODE (r
)
2342 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2343 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2344 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2345 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2346 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2353 while (GET_CODE (r
) == SUBREG
2354 || GET_CODE (r
) == STRICT_LOW_PART
2355 || GET_CODE (r
) == ZERO_EXTRACT
)
2360 int regno
= REGNO (r
);
2363 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2366 /* If this is a hard register, verify that subsequent
2367 words are not needed. */
2368 if (regno
< FIRST_PSEUDO_REGISTER
)
2370 int n
= hard_regno_nregs
[regno
][GET_MODE (r
)];
2373 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2377 /* Don't delete insns to set global regs. */
2378 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2381 /* Make sure insns to set the stack pointer aren't deleted. */
2382 if (regno
== STACK_POINTER_REGNUM
)
2385 /* ??? These bits might be redundant with the force live bits
2386 in calculate_global_regs_live. We would delete from
2387 sequential sets; whether this actually affects real code
2388 for anything but the stack pointer I don't know. */
2389 /* Make sure insns to set the frame pointer aren't deleted. */
2390 if (regno
== FRAME_POINTER_REGNUM
2391 && (! reload_completed
|| frame_pointer_needed
))
2393 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2394 if (regno
== HARD_FRAME_POINTER_REGNUM
2395 && (! reload_completed
|| frame_pointer_needed
))
2399 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2400 /* Make sure insns to set arg pointer are never deleted
2401 (if the arg pointer isn't fixed, there will be a USE
2402 for it, so we can treat it normally). */
2403 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2407 /* Otherwise, the set is dead. */
2413 /* If performing several activities, insn is dead if each activity
2414 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2415 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2417 else if (code
== PARALLEL
)
2419 int i
= XVECLEN (x
, 0);
2421 for (i
--; i
>= 0; i
--)
2422 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2423 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2424 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2430 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2431 is not necessarily true for hard registers until after reload. */
2432 else if (code
== CLOBBER
)
2434 if (REG_P (XEXP (x
, 0))
2435 && (REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2436 || reload_completed
)
2437 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2441 /* ??? A base USE is a historical relic. It ought not be needed anymore.
2442 Instances where it is still used are either (1) temporary and the USE
2443 escaped the pass, (2) cruft and the USE need not be emitted anymore,
2444 or (3) hiding bugs elsewhere that are not properly representing data
2450 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2451 return 1 if the entire library call is dead.
2452 This is true if INSN copies a register (hard or pseudo)
2453 and if the hard return reg of the call insn is dead.
2454 (The caller should have tested the destination of the SET inside
2455 INSN already for death.)
2457 If this insn doesn't just copy a register, then we don't
2458 have an ordinary libcall. In that case, cse could not have
2459 managed to substitute the source for the dest later on,
2460 so we can assume the libcall is dead.
2462 PBI is the block info giving pseudoregs live before this insn.
2463 NOTE is the REG_RETVAL note of the insn. */
2466 libcall_dead_p (struct propagate_block_info
*pbi
, rtx note
, rtx insn
)
2468 rtx x
= single_set (insn
);
2472 rtx r
= SET_SRC (x
);
2474 if (REG_P (r
) || GET_CODE (r
) == SUBREG
)
2476 rtx call
= XEXP (note
, 0);
2480 /* Find the call insn. */
2481 while (call
!= insn
&& !CALL_P (call
))
2482 call
= NEXT_INSN (call
);
2484 /* If there is none, do nothing special,
2485 since ordinary death handling can understand these insns. */
2489 /* See if the hard reg holding the value is dead.
2490 If this is a PARALLEL, find the call within it. */
2491 call_pat
= PATTERN (call
);
2492 if (GET_CODE (call_pat
) == PARALLEL
)
2494 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2495 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2496 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2499 /* This may be a library call that is returning a value
2500 via invisible pointer. Do nothing special, since
2501 ordinary death handling can understand these insns. */
2505 call_pat
= XVECEXP (call_pat
, 0, i
);
2508 if (! insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
)))
2511 while ((insn
= PREV_INSN (insn
)) != call
)
2513 if (! INSN_P (insn
))
2515 if (! insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
)))
2524 /* 1 if register REGNO was alive at a place where `setjmp' was called
2525 and was set more than once or is an argument.
2526 Such regs may be clobbered by `longjmp'. */
2529 regno_clobbered_at_setjmp (int regno
)
2531 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
2534 return ((REG_N_SETS (regno
) > 1
2535 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->il
.rtl
->global_live_at_end
,
2537 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2540 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2541 maximal list size; look for overlaps in mode and select the largest. */
2543 add_to_mem_set_list (struct propagate_block_info
*pbi
, rtx mem
)
2547 /* We don't know how large a BLKmode store is, so we must not
2548 take them into consideration. */
2549 if (GET_MODE (mem
) == BLKmode
)
2552 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2554 rtx e
= XEXP (i
, 0);
2555 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2557 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2560 /* If we must store a copy of the mem, we can just modify
2561 the mode of the stored copy. */
2562 if (pbi
->flags
& PROP_AUTOINC
)
2563 PUT_MODE (e
, GET_MODE (mem
));
2572 if (pbi
->mem_set_list_len
< PARAM_VALUE (PARAM_MAX_FLOW_MEMORY_LOCATIONS
))
2575 /* Store a copy of mem, otherwise the address may be
2576 scrogged by find_auto_inc. */
2577 if (pbi
->flags
& PROP_AUTOINC
)
2578 mem
= shallow_copy_rtx (mem
);
2580 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2581 pbi
->mem_set_list_len
++;
2585 /* INSN references memory, possibly using autoincrement addressing modes.
2586 Find any entries on the mem_set_list that need to be invalidated due
2587 to an address change. */
2590 invalidate_mems_from_autoinc (rtx
*px
, void *data
)
2593 struct propagate_block_info
*pbi
= data
;
2595 if (GET_RTX_CLASS (GET_CODE (x
)) == RTX_AUTOINC
)
2597 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2604 /* EXP is a REG or MEM. Remove any dependent entries from
2605 pbi->mem_set_list. */
2608 invalidate_mems_from_set (struct propagate_block_info
*pbi
, rtx exp
)
2610 rtx temp
= pbi
->mem_set_list
;
2611 rtx prev
= NULL_RTX
;
2616 next
= XEXP (temp
, 1);
2617 if ((REG_P (exp
) && reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2618 /* When we get an EXP that is a mem here, we want to check if EXP
2619 overlaps the *address* of any of the mems in the list (i.e. not
2620 whether the mems actually overlap; that's done elsewhere). */
2622 && reg_overlap_mentioned_p (exp
, XEXP (XEXP (temp
, 0), 0))))
2624 /* Splice this entry out of the list. */
2626 XEXP (prev
, 1) = next
;
2628 pbi
->mem_set_list
= next
;
2629 free_EXPR_LIST_node (temp
);
2630 pbi
->mem_set_list_len
--;
2638 /* Process the registers that are set within X. Their bits are set to
2639 1 in the regset DEAD, because they are dead prior to this insn.
2641 If INSN is nonzero, it is the insn being processed.
2643 FLAGS is the set of operations to perform. */
2646 mark_set_regs (struct propagate_block_info
*pbi
, rtx x
, rtx insn
)
2648 rtx cond
= NULL_RTX
;
2651 int flags
= pbi
->flags
;
2654 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2656 if (REG_NOTE_KIND (link
) == REG_INC
)
2657 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2658 (GET_CODE (x
) == COND_EXEC
2659 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2663 switch (code
= GET_CODE (x
))
2666 if (GET_CODE (XEXP (x
, 1)) == ASM_OPERANDS
)
2667 flags
|= PROP_ASM_SCAN
;
2670 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, flags
);
2674 cond
= COND_EXEC_TEST (x
);
2675 x
= COND_EXEC_CODE (x
);
2682 /* We must scan forwards. If we have an asm, we need to set
2683 the PROP_ASM_SCAN flag before scanning the clobbers. */
2684 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
2686 rtx sub
= XVECEXP (x
, 0, i
);
2687 switch (code
= GET_CODE (sub
))
2692 cond
= COND_EXEC_TEST (sub
);
2693 sub
= COND_EXEC_CODE (sub
);
2694 if (GET_CODE (sub
) == SET
)
2696 if (GET_CODE (sub
) == CLOBBER
)
2702 if (GET_CODE (XEXP (sub
, 1)) == ASM_OPERANDS
)
2703 flags
|= PROP_ASM_SCAN
;
2707 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, flags
);
2711 flags
|= PROP_ASM_SCAN
;
2726 /* Process a single set, which appears in INSN. REG (which may not
2727 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2728 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2729 If the set is conditional (because it appear in a COND_EXEC), COND
2730 will be the condition. */
2733 mark_set_1 (struct propagate_block_info
*pbi
, enum rtx_code code
, rtx reg
, rtx cond
, rtx insn
, int flags
)
2735 int regno_first
= -1, regno_last
= -1;
2736 unsigned long not_dead
= 0;
2739 /* Modifying just one hardware register of a multi-reg value or just a
2740 byte field of a register does not mean the value from before this insn
2741 is now dead. Of course, if it was dead after it's unused now. */
2743 switch (GET_CODE (reg
))
2746 /* Some targets place small structures in registers for return values of
2747 functions. We have to detect this case specially here to get correct
2748 flow information. */
2749 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2750 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2751 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2756 /* SIGN_EXTRACT cannot be an lvalue. */
2760 case STRICT_LOW_PART
:
2761 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2763 reg
= XEXP (reg
, 0);
2764 while (GET_CODE (reg
) == SUBREG
2765 || GET_CODE (reg
) == ZERO_EXTRACT
2766 || GET_CODE (reg
) == STRICT_LOW_PART
);
2769 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2773 regno_last
= regno_first
= REGNO (reg
);
2774 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2775 regno_last
+= hard_regno_nregs
[regno_first
][GET_MODE (reg
)] - 1;
2779 if (REG_P (SUBREG_REG (reg
)))
2781 enum machine_mode outer_mode
= GET_MODE (reg
);
2782 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2784 /* Identify the range of registers affected. This is moderately
2785 tricky for hard registers. See alter_subreg. */
2787 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2788 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2790 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2793 regno_last
= (regno_first
2794 + hard_regno_nregs
[regno_first
][outer_mode
] - 1);
2796 /* Since we've just adjusted the register number ranges, make
2797 sure REG matches. Otherwise some_was_live will be clear
2798 when it shouldn't have been, and we'll create incorrect
2799 REG_UNUSED notes. */
2800 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2804 /* If the number of words in the subreg is less than the number
2805 of words in the full register, we have a well-defined partial
2806 set. Otherwise the high bits are undefined.
2808 This is only really applicable to pseudos, since we just took
2809 care of multi-word hard registers. */
2810 if (((GET_MODE_SIZE (outer_mode
)
2811 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2812 < ((GET_MODE_SIZE (inner_mode
)
2813 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2814 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2817 reg
= SUBREG_REG (reg
);
2821 reg
= SUBREG_REG (reg
);
2828 /* If this set is a MEM, then it kills any aliased writes and any
2829 other MEMs which use it.
2830 If this set is a REG, then it kills any MEMs which use the reg. */
2831 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2833 if (REG_P (reg
) || MEM_P (reg
))
2834 invalidate_mems_from_set (pbi
, reg
);
2836 /* If the memory reference had embedded side effects (autoincrement
2837 address modes) then we may need to kill some entries on the
2839 if (insn
&& MEM_P (reg
))
2840 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2842 if (MEM_P (reg
) && ! side_effects_p (reg
)
2843 /* ??? With more effort we could track conditional memory life. */
2845 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2849 && ! (regno_first
== FRAME_POINTER_REGNUM
2850 && (! reload_completed
|| frame_pointer_needed
))
2851 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2852 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2853 && (! reload_completed
|| frame_pointer_needed
))
2855 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2856 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2860 int some_was_live
= 0, some_was_dead
= 0;
2862 for (i
= regno_first
; i
<= regno_last
; ++i
)
2864 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2867 /* Order of the set operation matters here since both
2868 sets may be the same. */
2869 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2870 if (cond
!= NULL_RTX
2871 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2872 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2874 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2876 if (code
!= CLOBBER
|| needed_regno
)
2877 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2879 some_was_live
|= needed_regno
;
2880 some_was_dead
|= ! needed_regno
;
2883 #ifdef HAVE_conditional_execution
2884 /* Consider conditional death in deciding that the register needs
2886 if (some_was_live
&& ! not_dead
2887 /* The stack pointer is never dead. Well, not strictly true,
2888 but it's very difficult to tell from here. Hopefully
2889 combine_stack_adjustments will fix up the most egregious
2891 && regno_first
!= STACK_POINTER_REGNUM
)
2893 for (i
= regno_first
; i
<= regno_last
; ++i
)
2894 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2895 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2899 /* Additional data to record if this is the final pass. */
2900 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2901 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2904 int blocknum
= pbi
->bb
->index
;
2907 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2909 y
= pbi
->reg_next_use
[regno_first
];
2911 /* The next use is no longer next, since a store intervenes. */
2912 for (i
= regno_first
; i
<= regno_last
; ++i
)
2913 pbi
->reg_next_use
[i
] = 0;
2916 if (flags
& PROP_REG_INFO
)
2918 for (i
= regno_first
; i
<= regno_last
; ++i
)
2920 /* Count (weighted) references, stores, etc. This counts a
2921 register twice if it is modified, but that is correct. */
2922 REG_N_SETS (i
) += 1;
2923 REG_N_REFS (i
) += 1;
2924 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2926 /* The insns where a reg is live are normally counted
2927 elsewhere, but we want the count to include the insn
2928 where the reg is set, and the normal counting mechanism
2929 would not count it. */
2930 REG_LIVE_LENGTH (i
) += 1;
2933 /* If this is a hard reg, record this function uses the reg. */
2934 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2936 for (i
= regno_first
; i
<= regno_last
; i
++)
2937 regs_ever_live
[i
] = 1;
2938 if (flags
& PROP_ASM_SCAN
)
2939 for (i
= regno_first
; i
<= regno_last
; i
++)
2940 regs_asm_clobbered
[i
] = 1;
2944 /* Keep track of which basic blocks each reg appears in. */
2945 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2946 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2947 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2948 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2952 if (! some_was_dead
)
2954 if (flags
& PROP_LOG_LINKS
)
2956 /* Make a logical link from the next following insn
2957 that uses this register, back to this insn.
2958 The following insns have already been processed.
2960 We don't build a LOG_LINK for hard registers containing
2961 in ASM_OPERANDs. If these registers get replaced,
2962 we might wind up changing the semantics of the insn,
2963 even if reload can make what appear to be valid
2966 We don't build a LOG_LINK for global registers to
2967 or from a function call. We don't want to let
2968 combine think that it knows what is going on with
2969 global registers. */
2970 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2971 && (regno_first
>= FIRST_PSEUDO_REGISTER
2972 || (asm_noperands (PATTERN (y
)) < 0
2973 && ! ((CALL_P (insn
)
2975 && global_regs
[regno_first
]))))
2976 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2981 else if (! some_was_live
)
2983 if (flags
& PROP_REG_INFO
)
2984 REG_N_DEATHS (regno_first
) += 1;
2986 if (flags
& PROP_DEATH_NOTES
2988 && (!(flags
& PROP_POST_REGSTACK
)
2989 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
,
2994 /* Note that dead stores have already been deleted
2995 when possible. If we get here, we have found a
2996 dead store that cannot be eliminated (because the
2997 same insn does something useful). Indicate this
2998 by marking the reg being set as dying here. */
3000 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
3005 if (flags
& PROP_DEATH_NOTES
3007 && (!(flags
& PROP_POST_REGSTACK
)
3008 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
,
3013 /* This is a case where we have a multi-word hard register
3014 and some, but not all, of the words of the register are
3015 needed in subsequent insns. Write REG_UNUSED notes
3016 for those parts that were not needed. This case should
3019 for (i
= regno_first
; i
<= regno_last
; ++i
)
3020 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
3022 = alloc_EXPR_LIST (REG_UNUSED
,
3029 /* Mark the register as being dead. */
3031 /* The stack pointer is never dead. Well, not strictly true,
3032 but it's very difficult to tell from here. Hopefully
3033 combine_stack_adjustments will fix up the most egregious
3035 && regno_first
!= STACK_POINTER_REGNUM
)
3037 for (i
= regno_first
; i
<= regno_last
; ++i
)
3038 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
3040 if ((pbi
->flags
& PROP_REG_INFO
)
3041 && REGNO_REG_SET_P (pbi
->reg_live
, i
))
3043 REG_LIVE_LENGTH (i
) += pbi
->insn_num
- reg_deaths
[i
];
3046 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
3048 if (flags
& PROP_DEAD_INSN
)
3049 emit_insn_after (gen_rtx_CLOBBER (VOIDmode
, reg
), insn
);
3052 else if (REG_P (reg
))
3054 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3055 pbi
->reg_next_use
[regno_first
] = 0;
3057 if ((flags
& PROP_REG_INFO
) != 0
3058 && (flags
& PROP_ASM_SCAN
) != 0
3059 && regno_first
< FIRST_PSEUDO_REGISTER
)
3061 for (i
= regno_first
; i
<= regno_last
; i
++)
3062 regs_asm_clobbered
[i
] = 1;
3066 /* If this is the last pass and this is a SCRATCH, show it will be dying
3067 here and count it. */
3068 else if (GET_CODE (reg
) == SCRATCH
)
3070 if (flags
& PROP_DEATH_NOTES
3072 && (!(flags
& PROP_POST_REGSTACK
)
3073 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
, LAST_STACK_REG
))
3077 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
3081 #ifdef HAVE_conditional_execution
3082 /* Mark REGNO conditionally dead.
3083 Return true if the register is now unconditionally dead. */
3086 mark_regno_cond_dead (struct propagate_block_info
*pbi
, int regno
, rtx cond
)
3088 /* If this is a store to a predicate register, the value of the
3089 predicate is changing, we don't know that the predicate as seen
3090 before is the same as that seen after. Flush all dependent
3091 conditions from reg_cond_dead. This will make all such
3092 conditionally live registers unconditionally live. */
3093 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
3094 flush_reg_cond_reg (pbi
, regno
);
3096 /* If this is an unconditional store, remove any conditional
3097 life that may have existed. */
3098 if (cond
== NULL_RTX
)
3099 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
3102 splay_tree_node node
;
3103 struct reg_cond_life_info
*rcli
;
3106 /* Otherwise this is a conditional set. Record that fact.
3107 It may have been conditionally used, or there may be a
3108 subsequent set with a complementary condition. */
3110 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
3113 /* The register was unconditionally live previously.
3114 Record the current condition as the condition under
3115 which it is dead. */
3116 rcli
= XNEW (struct reg_cond_life_info
);
3117 rcli
->condition
= cond
;
3118 rcli
->stores
= cond
;
3119 rcli
->orig_condition
= const0_rtx
;
3120 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
3121 (splay_tree_value
) rcli
);
3123 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3125 /* Not unconditionally dead. */
3130 /* The register was conditionally live previously.
3131 Add the new condition to the old. */
3132 rcli
= (struct reg_cond_life_info
*) node
->value
;
3133 ncond
= rcli
->condition
;
3134 ncond
= ior_reg_cond (ncond
, cond
, 1);
3135 if (rcli
->stores
== const0_rtx
)
3136 rcli
->stores
= cond
;
3137 else if (rcli
->stores
!= const1_rtx
)
3138 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
3140 /* If the register is now unconditionally dead, remove the entry
3141 in the splay_tree. A register is unconditionally dead if the
3142 dead condition ncond is true. A register is also unconditionally
3143 dead if the sum of all conditional stores is an unconditional
3144 store (stores is true), and the dead condition is identically the
3145 same as the original dead condition initialized at the end of
3146 the block. This is a pointer compare, not an rtx_equal_p
3148 if (ncond
== const1_rtx
3149 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
3150 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
3153 rcli
->condition
= ncond
;
3155 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3157 /* Not unconditionally dead. */
3166 /* Called from splay_tree_delete for pbi->reg_cond_life. */
3169 free_reg_cond_life_info (splay_tree_value value
)
3171 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
3175 /* Helper function for flush_reg_cond_reg. */
3178 flush_reg_cond_reg_1 (splay_tree_node node
, void *data
)
3180 struct reg_cond_life_info
*rcli
;
3181 int *xdata
= (int *) data
;
3182 unsigned int regno
= xdata
[0];
3184 /* Don't need to search if last flushed value was farther on in
3185 the in-order traversal. */
3186 if (xdata
[1] >= (int) node
->key
)
3189 /* Splice out portions of the expression that refer to regno. */
3190 rcli
= (struct reg_cond_life_info
*) node
->value
;
3191 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
3192 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
3193 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
3195 /* If the entire condition is now false, signal the node to be removed. */
3196 if (rcli
->condition
== const0_rtx
)
3198 xdata
[1] = node
->key
;
3202 gcc_assert (rcli
->condition
!= const1_rtx
);
3207 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3210 flush_reg_cond_reg (struct propagate_block_info
*pbi
, int regno
)
3216 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3217 flush_reg_cond_reg_1
, pair
) == -1)
3218 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3220 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3223 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3224 For ior/and, the ADD flag determines whether we want to add the new
3225 condition X to the old one unconditionally. If it is zero, we will
3226 only return a new expression if X allows us to simplify part of
3227 OLD, otherwise we return NULL to the caller.
3228 If ADD is nonzero, we will return a new condition in all cases. The
3229 toplevel caller of one of these functions should always pass 1 for
3233 ior_reg_cond (rtx old
, rtx x
, int add
)
3237 if (COMPARISON_P (old
))
3239 if (COMPARISON_P (x
)
3240 && REVERSE_CONDEXEC_PREDICATES_P (x
, old
)
3241 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3243 if (GET_CODE (x
) == GET_CODE (old
)
3244 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3248 return gen_rtx_IOR (0, old
, x
);
3251 switch (GET_CODE (old
))
3254 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3255 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3256 if (op0
!= NULL
|| op1
!= NULL
)
3258 if (op0
== const0_rtx
)
3259 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3260 if (op1
== const0_rtx
)
3261 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3262 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3265 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3266 else if (rtx_equal_p (x
, op0
))
3267 /* (x | A) | x ~ (x | A). */
3270 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3271 else if (rtx_equal_p (x
, op1
))
3272 /* (A | x) | x ~ (A | x). */
3274 return gen_rtx_IOR (0, op0
, op1
);
3278 return gen_rtx_IOR (0, old
, x
);
3281 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3282 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3283 if (op0
!= NULL
|| op1
!= NULL
)
3285 if (op0
== const1_rtx
)
3286 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3287 if (op1
== const1_rtx
)
3288 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3289 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3292 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3293 else if (rtx_equal_p (x
, op0
))
3294 /* (x & A) | x ~ x. */
3297 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3298 else if (rtx_equal_p (x
, op1
))
3299 /* (A & x) | x ~ x. */
3301 return gen_rtx_AND (0, op0
, op1
);
3305 return gen_rtx_IOR (0, old
, x
);
3308 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3310 return not_reg_cond (op0
);
3313 return gen_rtx_IOR (0, old
, x
);
3321 not_reg_cond (rtx x
)
3323 if (x
== const0_rtx
)
3325 else if (x
== const1_rtx
)
3327 if (GET_CODE (x
) == NOT
)
3329 if (COMPARISON_P (x
)
3330 && REG_P (XEXP (x
, 0)))
3332 gcc_assert (XEXP (x
, 1) == const0_rtx
);
3334 return gen_rtx_fmt_ee (reversed_comparison_code (x
, NULL
),
3335 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3337 return gen_rtx_NOT (0, x
);
3341 and_reg_cond (rtx old
, rtx x
, int add
)
3345 if (COMPARISON_P (old
))
3347 if (COMPARISON_P (x
)
3348 && GET_CODE (x
) == reversed_comparison_code (old
, NULL
)
3349 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3351 if (GET_CODE (x
) == GET_CODE (old
)
3352 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3356 return gen_rtx_AND (0, old
, x
);
3359 switch (GET_CODE (old
))
3362 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3363 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3364 if (op0
!= NULL
|| op1
!= NULL
)
3366 if (op0
== const0_rtx
)
3367 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3368 if (op1
== const0_rtx
)
3369 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3370 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3373 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3374 else if (rtx_equal_p (x
, op0
))
3375 /* (x | A) & x ~ x. */
3378 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3379 else if (rtx_equal_p (x
, op1
))
3380 /* (A | x) & x ~ x. */
3382 return gen_rtx_IOR (0, op0
, op1
);
3386 return gen_rtx_AND (0, old
, x
);
3389 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3390 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3391 if (op0
!= NULL
|| op1
!= NULL
)
3393 if (op0
== const1_rtx
)
3394 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3395 if (op1
== const1_rtx
)
3396 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3397 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3400 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3401 else if (rtx_equal_p (x
, op0
))
3402 /* (x & A) & x ~ (x & A). */
3405 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3406 else if (rtx_equal_p (x
, op1
))
3407 /* (A & x) & x ~ (A & x). */
3409 return gen_rtx_AND (0, op0
, op1
);
3413 return gen_rtx_AND (0, old
, x
);
3416 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3418 return not_reg_cond (op0
);
3421 return gen_rtx_AND (0, old
, x
);
3428 /* Given a condition X, remove references to reg REGNO and return the
3429 new condition. The removal will be done so that all conditions
3430 involving REGNO are considered to evaluate to false. This function
3431 is used when the value of REGNO changes. */
3434 elim_reg_cond (rtx x
, unsigned int regno
)
3438 if (COMPARISON_P (x
))
3440 if (REGNO (XEXP (x
, 0)) == regno
)
3445 switch (GET_CODE (x
))
3448 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3449 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3450 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3452 if (op0
== const1_rtx
)
3454 if (op1
== const1_rtx
)
3456 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3458 return gen_rtx_AND (0, op0
, op1
);
3461 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3462 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3463 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3465 if (op0
== const0_rtx
)
3467 if (op1
== const0_rtx
)
3469 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3471 return gen_rtx_IOR (0, op0
, op1
);
3474 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3475 if (op0
== const0_rtx
)
3477 if (op0
== const1_rtx
)
3479 if (op0
!= XEXP (x
, 0))
3480 return not_reg_cond (op0
);
3487 #endif /* HAVE_conditional_execution */
3491 /* Try to substitute the auto-inc expression INC as the address inside
3492 MEM which occurs in INSN. Currently, the address of MEM is an expression
3493 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3494 that has a single set whose source is a PLUS of INCR_REG and something
3498 attempt_auto_inc (struct propagate_block_info
*pbi
, rtx inc
, rtx insn
,
3499 rtx mem
, rtx incr
, rtx incr_reg
)
3501 int regno
= REGNO (incr_reg
);
3502 rtx set
= single_set (incr
);
3503 rtx q
= SET_DEST (set
);
3504 rtx y
= SET_SRC (set
);
3505 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3508 /* Make sure this reg appears only once in this insn. */
3509 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3512 if (dead_or_set_p (incr
, incr_reg
)
3513 /* Mustn't autoinc an eliminable register. */
3514 && (regno
>= FIRST_PSEUDO_REGISTER
3515 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3517 /* This is the simple case. Try to make the auto-inc. If
3518 we can't, we are done. Otherwise, we will do any
3519 needed updates below. */
3520 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3524 /* PREV_INSN used here to check the semi-open interval
3526 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3527 /* We must also check for sets of q as q may be
3528 a call clobbered hard register and there may
3529 be a call between PREV_INSN (insn) and incr. */
3530 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3532 /* We have *p followed sometime later by q = p+size.
3533 Both p and q must be live afterward,
3534 and q is not used between INSN and its assignment.
3535 Change it to q = p, ...*q..., q = q+size.
3536 Then fall into the usual case. */
3540 emit_move_insn (q
, incr_reg
);
3541 insns
= get_insns ();
3544 /* If we can't make the auto-inc, or can't make the
3545 replacement into Y, exit. There's no point in making
3546 the change below if we can't do the auto-inc and doing
3547 so is not correct in the pre-inc case. */
3550 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3551 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3552 if (! apply_change_group ())
3555 /* We now know we'll be doing this change, so emit the
3556 new insn(s) and do the updates. */
3557 emit_insn_before (insns
, insn
);
3559 if (BB_HEAD (pbi
->bb
) == insn
)
3560 BB_HEAD (pbi
->bb
) = insns
;
3562 /* INCR will become a NOTE and INSN won't contain a
3563 use of INCR_REG. If a use of INCR_REG was just placed in
3564 the insn before INSN, make that the next use.
3565 Otherwise, invalidate it. */
3566 if (NONJUMP_INSN_P (PREV_INSN (insn
))
3567 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3568 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3569 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3571 pbi
->reg_next_use
[regno
] = 0;
3576 if ((pbi
->flags
& PROP_REG_INFO
)
3577 && !REGNO_REG_SET_P (pbi
->reg_live
, regno
))
3578 reg_deaths
[regno
] = pbi
->insn_num
;
3580 /* REGNO is now used in INCR which is below INSN, but
3581 it previously wasn't live here. If we don't mark
3582 it as live, we'll put a REG_DEAD note for it
3583 on this insn, which is incorrect. */
3584 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3586 /* If there are any calls between INSN and INCR, show
3587 that REGNO now crosses them. */
3588 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3591 REG_N_CALLS_CROSSED (regno
)++;
3592 if (can_throw_internal (temp
))
3593 REG_N_THROWING_CALLS_CROSSED (regno
)++;
3596 /* Invalidate alias info for Q since we just changed its value. */
3597 clear_reg_alias_info (q
);
3602 /* If we haven't returned, it means we were able to make the
3603 auto-inc, so update the status. First, record that this insn
3604 has an implicit side effect. */
3606 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3608 /* Modify the old increment-insn to simply copy
3609 the already-incremented value of our register. */
3610 changed
= validate_change (incr
, &SET_SRC (set
), incr_reg
, 0);
3611 gcc_assert (changed
);
3613 /* If that makes it a no-op (copying the register into itself) delete
3614 it so it won't appear to be a "use" and a "set" of this
3616 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3618 /* If the original source was dead, it's dead now. */
3621 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3623 remove_note (incr
, note
);
3624 if (XEXP (note
, 0) != incr_reg
)
3626 unsigned int regno
= REGNO (XEXP (note
, 0));
3628 if ((pbi
->flags
& PROP_REG_INFO
)
3629 && REGNO_REG_SET_P (pbi
->reg_live
, regno
))
3631 REG_LIVE_LENGTH (regno
) += pbi
->insn_num
- reg_deaths
[regno
];
3632 reg_deaths
[regno
] = 0;
3634 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3638 SET_INSN_DELETED (incr
);
3641 if (regno
>= FIRST_PSEUDO_REGISTER
)
3643 /* Count an extra reference to the reg. When a reg is
3644 incremented, spilling it is worse, so we want to make
3645 that less likely. */
3646 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3648 /* Count the increment as a setting of the register,
3649 even though it isn't a SET in rtl. */
3650 REG_N_SETS (regno
)++;
3654 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3658 find_auto_inc (struct propagate_block_info
*pbi
, rtx x
, rtx insn
)
3660 rtx addr
= XEXP (x
, 0);
3661 HOST_WIDE_INT offset
= 0;
3662 rtx set
, y
, incr
, inc_val
;
3664 int size
= GET_MODE_SIZE (GET_MODE (x
));
3669 /* Here we detect use of an index register which might be good for
3670 postincrement, postdecrement, preincrement, or predecrement. */
3672 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3673 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3678 regno
= REGNO (addr
);
3680 /* Is the next use an increment that might make auto-increment? */
3681 incr
= pbi
->reg_next_use
[regno
];
3682 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3684 set
= single_set (incr
);
3685 if (set
== 0 || GET_CODE (set
) != SET
)
3689 if (GET_CODE (y
) != PLUS
)
3692 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3693 inc_val
= XEXP (y
, 1);
3694 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3695 inc_val
= XEXP (y
, 0);
3699 if (GET_CODE (inc_val
) == CONST_INT
)
3701 if (HAVE_POST_INCREMENT
3702 && (INTVAL (inc_val
) == size
&& offset
== 0))
3703 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3705 else if (HAVE_POST_DECREMENT
3706 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3707 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3709 else if (HAVE_PRE_INCREMENT
3710 && (INTVAL (inc_val
) == size
&& offset
== size
))
3711 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3713 else if (HAVE_PRE_DECREMENT
3714 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3715 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3717 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3718 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3719 gen_rtx_PLUS (Pmode
,
3722 insn
, x
, incr
, addr
);
3723 else if (HAVE_PRE_MODIFY_DISP
&& offset
== INTVAL (inc_val
))
3724 attempt_auto_inc (pbi
, gen_rtx_PRE_MODIFY (Pmode
, addr
,
3725 gen_rtx_PLUS (Pmode
,
3728 insn
, x
, incr
, addr
);
3730 else if (REG_P (inc_val
)
3731 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3735 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3736 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3737 gen_rtx_PLUS (Pmode
,
3740 insn
, x
, incr
, addr
);
3744 #endif /* AUTO_INC_DEC */
3747 mark_used_reg (struct propagate_block_info
*pbi
, rtx reg
,
3748 rtx cond ATTRIBUTE_UNUSED
, rtx insn
)
3750 unsigned int regno_first
, regno_last
, i
;
3751 int some_was_live
, some_was_dead
, some_not_set
;
3753 regno_last
= regno_first
= REGNO (reg
);
3754 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3755 regno_last
+= hard_regno_nregs
[regno_first
][GET_MODE (reg
)] - 1;
3757 /* Find out if any of this register is live after this instruction. */
3758 some_was_live
= some_was_dead
= 0;
3759 for (i
= regno_first
; i
<= regno_last
; ++i
)
3761 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3762 some_was_live
|= needed_regno
;
3763 some_was_dead
|= ! needed_regno
;
3766 /* Find out if any of the register was set this insn. */
3768 for (i
= regno_first
; i
<= regno_last
; ++i
)
3769 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3771 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3773 /* Record where each reg is used, so when the reg is set we know
3774 the next insn that uses it. */
3775 pbi
->reg_next_use
[regno_first
] = insn
;
3778 if (pbi
->flags
& PROP_REG_INFO
)
3780 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3782 /* If this is a register we are going to try to eliminate,
3783 don't mark it live here. If we are successful in
3784 eliminating it, it need not be live unless it is used for
3785 pseudos, in which case it will have been set live when it
3786 was allocated to the pseudos. If the register will not
3787 be eliminated, reload will set it live at that point.
3789 Otherwise, record that this function uses this register. */
3790 /* ??? The PPC backend tries to "eliminate" on the pic
3791 register to itself. This should be fixed. In the mean
3792 time, hack around it. */
3794 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3795 && (regno_first
== FRAME_POINTER_REGNUM
3796 || regno_first
== ARG_POINTER_REGNUM
)))
3797 for (i
= regno_first
; i
<= regno_last
; ++i
)
3798 regs_ever_live
[i
] = 1;
3802 /* Keep track of which basic block each reg appears in. */
3804 int blocknum
= pbi
->bb
->index
;
3805 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3806 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3807 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3808 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3810 /* Count (weighted) number of uses of each reg. */
3811 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3812 REG_N_REFS (regno_first
)++;
3814 for (i
= regno_first
; i
<= regno_last
; ++i
)
3815 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
3817 gcc_assert (!reg_deaths
[i
]);
3818 reg_deaths
[i
] = pbi
->insn_num
;
3822 /* Record and count the insns in which a reg dies. If it is used in
3823 this insn and was dead below the insn then it dies in this insn.
3824 If it was set in this insn, we do not make a REG_DEAD note;
3825 likewise if we already made such a note. */
3826 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3830 /* Check for the case where the register dying partially
3831 overlaps the register set by this insn. */
3832 if (regno_first
!= regno_last
)
3833 for (i
= regno_first
; i
<= regno_last
; ++i
)
3834 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3836 /* If none of the words in X is needed, make a REG_DEAD note.
3837 Otherwise, we must make partial REG_DEAD notes. */
3838 if (! some_was_live
)
3840 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3842 && (!(pbi
->flags
& PROP_POST_REGSTACK
)
3843 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
, LAST_STACK_REG
))
3845 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3847 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3849 if (pbi
->flags
& PROP_REG_INFO
)
3850 REG_N_DEATHS (regno_first
)++;
3854 /* Don't make a REG_DEAD note for a part of a register
3855 that is set in the insn. */
3856 for (i
= regno_first
; i
<= regno_last
; ++i
)
3857 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3858 && ! dead_or_set_regno_p (insn
, i
))
3860 = alloc_EXPR_LIST (REG_DEAD
,
3866 /* Mark the register as being live. */
3867 for (i
= regno_first
; i
<= regno_last
; ++i
)
3869 #ifdef HAVE_conditional_execution
3870 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3873 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3875 #ifdef HAVE_conditional_execution
3876 /* If this is a conditional use, record that fact. If it is later
3877 conditionally set, we'll know to kill the register. */
3878 if (cond
!= NULL_RTX
)
3880 splay_tree_node node
;
3881 struct reg_cond_life_info
*rcli
;
3886 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3889 /* The register was unconditionally live previously.
3890 No need to do anything. */
3894 /* The register was conditionally live previously.
3895 Subtract the new life cond from the old death cond. */
3896 rcli
= (struct reg_cond_life_info
*) node
->value
;
3897 ncond
= rcli
->condition
;
3898 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3900 /* If the register is now unconditionally live,
3901 remove the entry in the splay_tree. */
3902 if (ncond
== const0_rtx
)
3903 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3906 rcli
->condition
= ncond
;
3907 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3908 REGNO (XEXP (cond
, 0)));
3914 /* The register was not previously live at all. Record
3915 the condition under which it is still dead. */
3916 rcli
= XNEW (struct reg_cond_life_info
);
3917 rcli
->condition
= not_reg_cond (cond
);
3918 rcli
->stores
= const0_rtx
;
3919 rcli
->orig_condition
= const0_rtx
;
3920 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3921 (splay_tree_value
) rcli
);
3923 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3926 else if (this_was_live
)
3928 /* The register may have been conditionally live previously, but
3929 is now unconditionally live. Remove it from the conditionally
3930 dead list, so that a conditional set won't cause us to think
3932 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3938 /* Scan expression X for registers which have to be marked used in PBI.
3939 X is considered to be the SET_DEST rtx of SET. TRUE is returned if
3940 X could be handled by this function. */
3943 mark_used_dest_regs (struct propagate_block_info
*pbi
, rtx x
, rtx cond
, rtx insn
)
3946 bool mark_dest
= false;
3949 /* On some platforms calls return values spread over several
3950 locations. These locations are wrapped in a EXPR_LIST rtx
3951 together with a CONST_INT offset. */
3952 if (GET_CODE (x
) == EXPR_LIST
3953 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
3959 /* If storing into MEM, don't show it as being used. But do
3960 show the address as being used. */
3964 if (pbi
->flags
& PROP_AUTOINC
)
3965 find_auto_inc (pbi
, x
, insn
);
3967 mark_used_regs (pbi
, XEXP (x
, 0), cond
, insn
);
3971 /* Storing in STRICT_LOW_PART is like storing in a reg
3972 in that this SET might be dead, so ignore it in TESTREG.
3973 but in some other ways it is like using the reg.
3975 Storing in a SUBREG or a bit field is like storing the entire
3976 register in that if the register's value is not used
3977 then this SET is not needed. */
3978 while (GET_CODE (x
) == STRICT_LOW_PART
3979 || GET_CODE (x
) == ZERO_EXTRACT
3980 || GET_CODE (x
) == SUBREG
)
3982 #ifdef CANNOT_CHANGE_MODE_CLASS
3983 if ((pbi
->flags
& PROP_REG_INFO
) && GET_CODE (x
) == SUBREG
)
3984 record_subregs_of_mode (x
);
3987 /* Modifying a single register in an alternate mode
3988 does not use any of the old value. But these other
3989 ways of storing in a register do use the old value. */
3990 if (GET_CODE (x
) == SUBREG
3991 && !((REG_BYTES (SUBREG_REG (x
))
3992 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3994 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
4002 /* If this is a store into a register or group of registers,
4003 recursively scan the value being stored. */
4005 && (regno
= REGNO (x
),
4006 !(regno
== FRAME_POINTER_REGNUM
4007 && (!reload_completed
|| frame_pointer_needed
)))
4008 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4009 && !(regno
== HARD_FRAME_POINTER_REGNUM
4010 && (!reload_completed
|| frame_pointer_needed
))
4012 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4013 && !(regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
4018 mark_used_regs (pbi
, dest
, cond
, insn
);
4024 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
4025 This is done assuming the registers needed from X are those that
4026 have 1-bits in PBI->REG_LIVE.
4028 INSN is the containing instruction. If INSN is dead, this function
4032 mark_used_regs (struct propagate_block_info
*pbi
, rtx x
, rtx cond
, rtx insn
)
4035 int flags
= pbi
->flags
;
4040 code
= GET_CODE (x
);
4061 /* If we are clobbering a MEM, mark any registers inside the address
4063 if (MEM_P (XEXP (x
, 0)))
4064 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
4068 /* Don't bother watching stores to mems if this is not the
4069 final pass. We'll not be deleting dead stores this round. */
4070 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
4072 /* Invalidate the data for the last MEM stored, but only if MEM is
4073 something that can be stored into. */
4074 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
4075 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
4076 /* Needn't clear the memory set list. */
4080 rtx temp
= pbi
->mem_set_list
;
4081 rtx prev
= NULL_RTX
;
4086 next
= XEXP (temp
, 1);
4087 if (anti_dependence (XEXP (temp
, 0), x
))
4089 /* Splice temp out of the list. */
4091 XEXP (prev
, 1) = next
;
4093 pbi
->mem_set_list
= next
;
4094 free_EXPR_LIST_node (temp
);
4095 pbi
->mem_set_list_len
--;
4103 /* If the memory reference had embedded side effects (autoincrement
4104 address modes. Then we may need to kill some entries on the
4107 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
4111 if (flags
& PROP_AUTOINC
)
4112 find_auto_inc (pbi
, x
, insn
);
4117 #ifdef CANNOT_CHANGE_MODE_CLASS
4118 if (flags
& PROP_REG_INFO
)
4119 record_subregs_of_mode (x
);
4122 /* While we're here, optimize this case. */
4129 /* See a register other than being set => mark it as needed. */
4130 mark_used_reg (pbi
, x
, cond
, insn
);
4135 rtx dest
= SET_DEST (x
);
4139 if (GET_CODE (dest
) == PARALLEL
)
4140 for (i
= 0; i
< XVECLEN (dest
, 0); i
++)
4141 ret
|= mark_used_dest_regs (pbi
, XVECEXP (dest
, 0, i
), cond
, insn
);
4143 ret
= mark_used_dest_regs (pbi
, dest
, cond
, insn
);
4147 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
4154 case UNSPEC_VOLATILE
:
4158 /* Traditional and volatile asm instructions must be considered to use
4159 and clobber all hard registers, all pseudo-registers and all of
4160 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
4162 Consider for instance a volatile asm that changes the fpu rounding
4163 mode. An insn should not be moved across this even if it only uses
4164 pseudo-regs because it might give an incorrectly rounded result.
4166 ?!? Unfortunately, marking all hard registers as live causes massive
4167 problems for the register allocator and marking all pseudos as live
4168 creates mountains of uninitialized variable warnings.
4170 So for now, just clear the memory set list and mark any regs
4171 we can find in ASM_OPERANDS as used. */
4172 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
4174 free_EXPR_LIST_list (&pbi
->mem_set_list
);
4175 pbi
->mem_set_list_len
= 0;
4178 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
4179 We can not just fall through here since then we would be confused
4180 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
4181 traditional asms unlike their normal usage. */
4182 if (code
== ASM_OPERANDS
)
4186 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
4187 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
4195 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
4197 cond
= COND_EXEC_TEST (x
);
4198 x
= COND_EXEC_CODE (x
);
4205 /* Recursively scan the operands of this expression. */
4208 const char * const fmt
= GET_RTX_FORMAT (code
);
4211 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4215 /* Tail recursive case: save a function call level. */
4221 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
4223 else if (fmt
[i
] == 'E')
4226 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4227 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4236 try_pre_increment_1 (struct propagate_block_info
*pbi
, rtx insn
)
4238 /* Find the next use of this reg. If in same basic block,
4239 make it do pre-increment or pre-decrement if appropriate. */
4240 rtx x
= single_set (insn
);
4241 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4242 * INTVAL (XEXP (SET_SRC (x
), 1)));
4243 int regno
= REGNO (SET_DEST (x
));
4244 rtx y
= pbi
->reg_next_use
[regno
];
4246 && SET_DEST (x
) != stack_pointer_rtx
4247 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4248 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4249 mode would be better. */
4250 && ! dead_or_set_p (y
, SET_DEST (x
))
4251 && try_pre_increment (y
, SET_DEST (x
), amount
))
4253 /* We have found a suitable auto-increment and already changed
4254 insn Y to do it. So flush this increment instruction. */
4255 propagate_block_delete_insn (insn
);
4257 /* Count a reference to this reg for the increment insn we are
4258 deleting. When a reg is incremented, spilling it is worse,
4259 so we want to make that less likely. */
4260 if (regno
>= FIRST_PSEUDO_REGISTER
)
4262 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4263 REG_N_SETS (regno
)++;
4266 /* Flush any remembered memories depending on the value of
4267 the incremented register. */
4268 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4275 /* Try to change INSN so that it does pre-increment or pre-decrement
4276 addressing on register REG in order to add AMOUNT to REG.
4277 AMOUNT is negative for pre-decrement.
4278 Returns 1 if the change could be made.
4279 This checks all about the validity of the result of modifying INSN. */
4282 try_pre_increment (rtx insn
, rtx reg
, HOST_WIDE_INT amount
)
4286 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4287 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4289 /* Nonzero if we can try to make a post-increment or post-decrement.
4290 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4291 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4292 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4295 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4298 /* From the sign of increment, see which possibilities are conceivable
4299 on this target machine. */
4300 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4302 if (HAVE_POST_INCREMENT
&& amount
> 0)
4305 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4307 if (HAVE_POST_DECREMENT
&& amount
< 0)
4310 if (! (pre_ok
|| post_ok
))
4313 /* It is not safe to add a side effect to a jump insn
4314 because if the incremented register is spilled and must be reloaded
4315 there would be no way to store the incremented value back in memory. */
4322 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4323 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4325 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4329 if (use
== 0 || use
== (rtx
) (size_t) 1)
4332 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4335 /* See if this combination of instruction and addressing mode exists. */
4336 if (! validate_change (insn
, &XEXP (use
, 0),
4337 gen_rtx_fmt_e (amount
> 0
4338 ? (do_post
? POST_INC
: PRE_INC
)
4339 : (do_post
? POST_DEC
: PRE_DEC
),
4343 /* Record that this insn now has an implicit side effect on X. */
4344 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4348 #endif /* AUTO_INC_DEC */
4350 /* Find the place in the rtx X where REG is used as a memory address.
4351 Return the MEM rtx that so uses it.
4352 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4353 (plus REG (const_int PLUSCONST)).
4355 If such an address does not appear, return 0.
4356 If REG appears more than once, or is used other than in such an address,
4360 find_use_as_address (rtx x
, rtx reg
, HOST_WIDE_INT plusconst
)
4362 enum rtx_code code
= GET_CODE (x
);
4363 const char * const fmt
= GET_RTX_FORMAT (code
);
4368 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4371 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4372 && XEXP (XEXP (x
, 0), 0) == reg
4373 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4374 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4377 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4379 /* If REG occurs inside a MEM used in a bit-field reference,
4380 that is unacceptable. */
4381 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4382 return (rtx
) (size_t) 1;
4386 return (rtx
) (size_t) 1;
4388 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4392 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4396 return (rtx
) (size_t) 1;
4398 else if (fmt
[i
] == 'E')
4401 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4403 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4407 return (rtx
) (size_t) 1;
4415 /* Write information about registers and basic blocks into FILE.
4416 This is part of making a debugging dump. */
4419 dump_regset (regset r
, FILE *outf
)
4422 reg_set_iterator rsi
;
4426 fputs (" (nil)", outf
);
4430 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
, rsi
)
4432 fprintf (outf
, " %d", i
);
4433 if (i
< FIRST_PSEUDO_REGISTER
)
4434 fprintf (outf
, " [%s]",
4439 /* Print a human-readable representation of R on the standard error
4440 stream. This function is designed to be used from within the
4444 debug_regset (regset r
)
4446 dump_regset (r
, stderr
);
4447 putc ('\n', stderr
);
4450 /* Recompute register set/reference counts immediately prior to register
4453 This avoids problems with set/reference counts changing to/from values
4454 which have special meanings to the register allocators.
4456 Additionally, the reference counts are the primary component used by the
4457 register allocators to prioritize pseudos for allocation to hard regs.
4458 More accurate reference counts generally lead to better register allocation.
4460 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4461 possibly other information which is used by the register allocators. */
4464 recompute_reg_usage (void)
4466 allocate_reg_life_data ();
4467 /* distribute_notes in combiner fails to convert some of the
4468 REG_UNUSED notes to REG_DEAD notes. This causes CHECK_DEAD_NOTES
4469 in sched1 to die. To solve this update the DEATH_NOTES
4471 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
| PROP_DEATH_NOTES
);
4474 dump_flow_info (dump_file
, dump_flags
);
4478 struct tree_opt_pass pass_recompute_reg_usage
=
4482 recompute_reg_usage
, /* execute */
4485 0, /* static_pass_number */
4487 0, /* properties_required */
4488 0, /* properties_provided */
4489 0, /* properties_destroyed */
4490 0, /* todo_flags_start */
4491 TODO_dump_func
, /* todo_flags_finish */
4495 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4496 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4497 of the number of registers that died.
4498 If KILL is 1, remove old REG_DEAD / REG_UNUSED notes. If it is 0, don't.
4499 if it is -1, remove them unless they pertain to a stack reg. */
4502 count_or_remove_death_notes (sbitmap blocks
, int kill
)
4508 /* This used to be a loop over all the blocks with a membership test
4509 inside the loop. That can be amazingly expensive on a large CFG
4510 when only a small number of bits are set in BLOCKs (for example,
4511 the calls from the scheduler typically have very few bits set).
4513 For extra credit, someone should convert BLOCKS to a bitmap rather
4517 sbitmap_iterator sbi
;
4519 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
, sbi
)
4521 basic_block bb
= BASIC_BLOCK (i
);
4522 /* The bitmap may be flawed in that one of the basic blocks
4523 may have been deleted before you get here. */
4525 count
+= count_or_remove_death_notes_bb (bb
, kill
);
4532 count
+= count_or_remove_death_notes_bb (bb
, kill
);
4539 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from basic
4540 block BB. Returns a count of the number of registers that died. */
4543 count_or_remove_death_notes_bb (basic_block bb
, int kill
)
4548 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
4552 rtx
*pprev
= ®_NOTES (insn
);
4557 switch (REG_NOTE_KIND (link
))
4560 if (REG_P (XEXP (link
, 0)))
4562 rtx reg
= XEXP (link
, 0);
4565 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4568 n
= hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)];
4578 && (!REG_P (XEXP (link
, 0))
4579 || !IN_RANGE (REGNO (XEXP (link
, 0)),
4580 FIRST_STACK_REG
, LAST_STACK_REG
))
4584 rtx next
= XEXP (link
, 1);
4585 free_EXPR_LIST_node (link
);
4586 *pprev
= link
= next
;
4592 pprev
= &XEXP (link
, 1);
4599 if (insn
== BB_END (bb
))
4606 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4607 if blocks is NULL. */
4610 clear_log_links (sbitmap blocks
)
4616 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4618 free_INSN_LIST_list (&LOG_LINKS (insn
));
4623 sbitmap_iterator sbi
;
4625 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
, sbi
)
4627 basic_block bb
= BASIC_BLOCK (i
);
4629 for (insn
= BB_HEAD (bb
); insn
!= NEXT_INSN (BB_END (bb
));
4630 insn
= NEXT_INSN (insn
))
4632 free_INSN_LIST_list (&LOG_LINKS (insn
));
4637 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4638 correspond to the hard registers, if any, set in that map. This
4639 could be done far more efficiently by having all sorts of special-cases
4640 with moving single words, but probably isn't worth the trouble. */
4643 reg_set_to_hard_reg_set (HARD_REG_SET
*to
, bitmap from
)
4648 EXECUTE_IF_SET_IN_BITMAP (from
, 0, i
, bi
)
4650 if (i
>= FIRST_PSEUDO_REGISTER
)
4652 SET_HARD_REG_BIT (*to
, i
);
4658 gate_remove_death_notes (void)
4660 return flag_profile_values
;
4664 rest_of_handle_remove_death_notes (void)
4666 count_or_remove_death_notes (NULL
, 1);
4670 struct tree_opt_pass pass_remove_death_notes
=
4672 "ednotes", /* name */
4673 gate_remove_death_notes
, /* gate */
4674 rest_of_handle_remove_death_notes
, /* execute */
4677 0, /* static_pass_number */
4679 0, /* properties_required */
4680 0, /* properties_provided */
4681 0, /* properties_destroyed */
4682 0, /* todo_flags_start */
4683 0, /* todo_flags_finish */
4687 /* Perform life analysis. */
4689 rest_of_handle_life (void)
4693 life_analysis (PROP_FINAL
);
4695 cleanup_cfg (CLEANUP_EXPENSIVE
| CLEANUP_UPDATE_LIFE
| CLEANUP_LOG_LINKS
4696 | (flag_thread_jumps
? CLEANUP_THREADING
: 0));
4700 setjmp_vars_warning (DECL_INITIAL (current_function_decl
));
4701 setjmp_args_warning ();
4706 if (initialize_uninitialized_subregs ())
4708 /* Insns were inserted, and possibly pseudos created, so
4709 things might look a bit different. */
4710 allocate_reg_life_data ();
4711 update_life_info (NULL
, UPDATE_LIFE_GLOBAL_RM_NOTES
,
4712 PROP_LOG_LINKS
| PROP_REG_INFO
| PROP_DEATH_NOTES
);
4720 struct tree_opt_pass pass_life
=
4724 rest_of_handle_life
, /* execute */
4727 0, /* static_pass_number */
4728 TV_FLOW
, /* tv_id */
4729 0, /* properties_required */
4730 0, /* properties_provided */
4731 0, /* properties_destroyed */
4732 TODO_verify_flow
, /* todo_flags_start */
4734 TODO_ggc_collect
, /* todo_flags_finish */
4739 rest_of_handle_flow2 (void)
4741 /* If optimizing, then go ahead and split insns now. */
4745 split_all_insns (0);
4747 if (flag_branch_target_load_optimize
)
4748 branch_target_load_optimize (epilogue_completed
);
4751 cleanup_cfg (CLEANUP_EXPENSIVE
);
4753 /* On some machines, the prologue and epilogue code, or parts thereof,
4754 can be represented as RTL. Doing so lets us schedule insns between
4755 it and the rest of the code and also allows delayed branch
4756 scheduling to operate in the epilogue. */
4757 thread_prologue_and_epilogue_insns (get_insns ());
4758 epilogue_completed
= 1;
4759 flow2_completed
= 1;
4763 struct tree_opt_pass pass_flow2
=
4767 rest_of_handle_flow2
, /* execute */
4770 0, /* static_pass_number */
4771 TV_FLOW2
, /* tv_id */
4772 0, /* properties_required */
4773 0, /* properties_provided */
4774 0, /* properties_destroyed */
4775 TODO_verify_flow
, /* todo_flags_start */
4777 TODO_ggc_collect
, /* todo_flags_finish */