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
)
2308 else if (GET_CODE (SET_SRC (x
)) == UNSPEC
&&
2309 XINT (SET_SRC (x
), 1) == UNSPEC_NACLCALL
)
2315 /* Don't eliminate loads from volatile memory or volatile asms. */
2316 else if (volatile_refs_p (SET_SRC (x
)))
2323 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2326 canon_r
= canon_rtx (r
);
2328 /* Walk the set of memory locations we are currently tracking
2329 and see if one is an identical match to this memory location.
2330 If so, this memory write is dead (remember, we're walking
2331 backwards from the end of the block to the start). Since
2332 rtx_equal_p does not check the alias set or flags, we also
2333 must have the potential for them to conflict (anti_dependence). */
2334 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2335 if (anti_dependence (r
, XEXP (temp
, 0)))
2337 rtx mem
= XEXP (temp
, 0);
2339 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2340 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2341 <= GET_MODE_SIZE (GET_MODE (mem
))))
2345 /* Check if memory reference matches an auto increment. Only
2346 post increment/decrement or modify are valid. */
2347 if (GET_MODE (mem
) == GET_MODE (r
)
2348 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2349 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2350 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2351 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2352 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2359 while (GET_CODE (r
) == SUBREG
2360 || GET_CODE (r
) == STRICT_LOW_PART
2361 || GET_CODE (r
) == ZERO_EXTRACT
)
2366 int regno
= REGNO (r
);
2369 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2372 /* If this is a hard register, verify that subsequent
2373 words are not needed. */
2374 if (regno
< FIRST_PSEUDO_REGISTER
)
2376 int n
= hard_regno_nregs
[regno
][GET_MODE (r
)];
2379 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2383 /* Don't delete insns to set global regs. */
2384 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2387 /* Make sure insns to set the stack pointer aren't deleted. */
2388 if (regno
== STACK_POINTER_REGNUM
)
2391 /* ??? These bits might be redundant with the force live bits
2392 in calculate_global_regs_live. We would delete from
2393 sequential sets; whether this actually affects real code
2394 for anything but the stack pointer I don't know. */
2395 /* Make sure insns to set the frame pointer aren't deleted. */
2396 if (regno
== FRAME_POINTER_REGNUM
2397 && (! reload_completed
|| frame_pointer_needed
))
2399 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2400 if (regno
== HARD_FRAME_POINTER_REGNUM
2401 && (! reload_completed
|| frame_pointer_needed
))
2405 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2406 /* Make sure insns to set arg pointer are never deleted
2407 (if the arg pointer isn't fixed, there will be a USE
2408 for it, so we can treat it normally). */
2409 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2413 /* Otherwise, the set is dead. */
2419 /* If performing several activities, insn is dead if each activity
2420 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2421 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2423 else if (code
== PARALLEL
)
2425 int i
= XVECLEN (x
, 0);
2427 for (i
--; i
>= 0; i
--)
2428 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2429 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2430 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2436 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2437 is not necessarily true for hard registers until after reload. */
2438 else if (code
== CLOBBER
)
2440 if (REG_P (XEXP (x
, 0))
2441 && (REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2442 || reload_completed
)
2443 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2447 /* ??? A base USE is a historical relic. It ought not be needed anymore.
2448 Instances where it is still used are either (1) temporary and the USE
2449 escaped the pass, (2) cruft and the USE need not be emitted anymore,
2450 or (3) hiding bugs elsewhere that are not properly representing data
2456 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2457 return 1 if the entire library call is dead.
2458 This is true if INSN copies a register (hard or pseudo)
2459 and if the hard return reg of the call insn is dead.
2460 (The caller should have tested the destination of the SET inside
2461 INSN already for death.)
2463 If this insn doesn't just copy a register, then we don't
2464 have an ordinary libcall. In that case, cse could not have
2465 managed to substitute the source for the dest later on,
2466 so we can assume the libcall is dead.
2468 PBI is the block info giving pseudoregs live before this insn.
2469 NOTE is the REG_RETVAL note of the insn. */
2472 libcall_dead_p (struct propagate_block_info
*pbi
, rtx note
, rtx insn
)
2474 rtx x
= single_set (insn
);
2478 rtx r
= SET_SRC (x
);
2480 if (REG_P (r
) || GET_CODE (r
) == SUBREG
)
2482 rtx call
= XEXP (note
, 0);
2486 /* Find the call insn. */
2487 while (call
!= insn
&& !CALL_P (call
))
2488 call
= NEXT_INSN (call
);
2490 /* If there is none, do nothing special,
2491 since ordinary death handling can understand these insns. */
2495 /* See if the hard reg holding the value is dead.
2496 If this is a PARALLEL, find the call within it. */
2497 call_pat
= PATTERN (call
);
2498 if (GET_CODE (call_pat
) == PARALLEL
)
2500 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2501 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2502 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2505 /* This may be a library call that is returning a value
2506 via invisible pointer. Do nothing special, since
2507 ordinary death handling can understand these insns. */
2511 call_pat
= XVECEXP (call_pat
, 0, i
);
2514 if (! insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
)))
2517 while ((insn
= PREV_INSN (insn
)) != call
)
2519 if (! INSN_P (insn
))
2521 if (! insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
)))
2530 /* 1 if register REGNO was alive at a place where `setjmp' was called
2531 and was set more than once or is an argument.
2532 Such regs may be clobbered by `longjmp'. */
2535 regno_clobbered_at_setjmp (int regno
)
2537 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
2540 return ((REG_N_SETS (regno
) > 1
2541 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->il
.rtl
->global_live_at_end
,
2543 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2546 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2547 maximal list size; look for overlaps in mode and select the largest. */
2549 add_to_mem_set_list (struct propagate_block_info
*pbi
, rtx mem
)
2553 /* We don't know how large a BLKmode store is, so we must not
2554 take them into consideration. */
2555 if (GET_MODE (mem
) == BLKmode
)
2558 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2560 rtx e
= XEXP (i
, 0);
2561 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2563 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2566 /* If we must store a copy of the mem, we can just modify
2567 the mode of the stored copy. */
2568 if (pbi
->flags
& PROP_AUTOINC
)
2569 PUT_MODE (e
, GET_MODE (mem
));
2578 if (pbi
->mem_set_list_len
< PARAM_VALUE (PARAM_MAX_FLOW_MEMORY_LOCATIONS
))
2581 /* Store a copy of mem, otherwise the address may be
2582 scrogged by find_auto_inc. */
2583 if (pbi
->flags
& PROP_AUTOINC
)
2584 mem
= shallow_copy_rtx (mem
);
2586 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2587 pbi
->mem_set_list_len
++;
2591 /* INSN references memory, possibly using autoincrement addressing modes.
2592 Find any entries on the mem_set_list that need to be invalidated due
2593 to an address change. */
2596 invalidate_mems_from_autoinc (rtx
*px
, void *data
)
2599 struct propagate_block_info
*pbi
= data
;
2601 if (GET_RTX_CLASS (GET_CODE (x
)) == RTX_AUTOINC
)
2603 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2610 /* EXP is a REG or MEM. Remove any dependent entries from
2611 pbi->mem_set_list. */
2614 invalidate_mems_from_set (struct propagate_block_info
*pbi
, rtx exp
)
2616 rtx temp
= pbi
->mem_set_list
;
2617 rtx prev
= NULL_RTX
;
2622 next
= XEXP (temp
, 1);
2623 if ((REG_P (exp
) && reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2624 /* When we get an EXP that is a mem here, we want to check if EXP
2625 overlaps the *address* of any of the mems in the list (i.e. not
2626 whether the mems actually overlap; that's done elsewhere). */
2628 && reg_overlap_mentioned_p (exp
, XEXP (XEXP (temp
, 0), 0))))
2630 /* Splice this entry out of the list. */
2632 XEXP (prev
, 1) = next
;
2634 pbi
->mem_set_list
= next
;
2635 free_EXPR_LIST_node (temp
);
2636 pbi
->mem_set_list_len
--;
2644 /* Process the registers that are set within X. Their bits are set to
2645 1 in the regset DEAD, because they are dead prior to this insn.
2647 If INSN is nonzero, it is the insn being processed.
2649 FLAGS is the set of operations to perform. */
2652 mark_set_regs (struct propagate_block_info
*pbi
, rtx x
, rtx insn
)
2654 rtx cond
= NULL_RTX
;
2657 int flags
= pbi
->flags
;
2660 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2662 if (REG_NOTE_KIND (link
) == REG_INC
)
2663 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2664 (GET_CODE (x
) == COND_EXEC
2665 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2669 switch (code
= GET_CODE (x
))
2672 if (GET_CODE (XEXP (x
, 1)) == ASM_OPERANDS
)
2673 flags
|= PROP_ASM_SCAN
;
2676 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, flags
);
2680 cond
= COND_EXEC_TEST (x
);
2681 x
= COND_EXEC_CODE (x
);
2688 /* We must scan forwards. If we have an asm, we need to set
2689 the PROP_ASM_SCAN flag before scanning the clobbers. */
2690 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
2692 rtx sub
= XVECEXP (x
, 0, i
);
2693 switch (code
= GET_CODE (sub
))
2698 cond
= COND_EXEC_TEST (sub
);
2699 sub
= COND_EXEC_CODE (sub
);
2700 if (GET_CODE (sub
) == SET
)
2702 if (GET_CODE (sub
) == CLOBBER
)
2708 if (GET_CODE (XEXP (sub
, 1)) == ASM_OPERANDS
)
2709 flags
|= PROP_ASM_SCAN
;
2713 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, flags
);
2717 flags
|= PROP_ASM_SCAN
;
2732 /* Process a single set, which appears in INSN. REG (which may not
2733 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2734 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2735 If the set is conditional (because it appear in a COND_EXEC), COND
2736 will be the condition. */
2739 mark_set_1 (struct propagate_block_info
*pbi
, enum rtx_code code
, rtx reg
, rtx cond
, rtx insn
, int flags
)
2741 int regno_first
= -1, regno_last
= -1;
2742 unsigned long not_dead
= 0;
2745 /* Modifying just one hardware register of a multi-reg value or just a
2746 byte field of a register does not mean the value from before this insn
2747 is now dead. Of course, if it was dead after it's unused now. */
2749 switch (GET_CODE (reg
))
2752 /* Some targets place small structures in registers for return values of
2753 functions. We have to detect this case specially here to get correct
2754 flow information. */
2755 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2756 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2757 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2762 /* SIGN_EXTRACT cannot be an lvalue. */
2766 case STRICT_LOW_PART
:
2767 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2769 reg
= XEXP (reg
, 0);
2770 while (GET_CODE (reg
) == SUBREG
2771 || GET_CODE (reg
) == ZERO_EXTRACT
2772 || GET_CODE (reg
) == STRICT_LOW_PART
);
2775 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2779 regno_last
= regno_first
= REGNO (reg
);
2780 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2781 regno_last
+= hard_regno_nregs
[regno_first
][GET_MODE (reg
)] - 1;
2785 if (REG_P (SUBREG_REG (reg
)))
2787 enum machine_mode outer_mode
= GET_MODE (reg
);
2788 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2790 /* Identify the range of registers affected. This is moderately
2791 tricky for hard registers. See alter_subreg. */
2793 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2794 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2796 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2799 regno_last
= (regno_first
2800 + hard_regno_nregs
[regno_first
][outer_mode
] - 1);
2802 /* Since we've just adjusted the register number ranges, make
2803 sure REG matches. Otherwise some_was_live will be clear
2804 when it shouldn't have been, and we'll create incorrect
2805 REG_UNUSED notes. */
2806 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2810 /* If the number of words in the subreg is less than the number
2811 of words in the full register, we have a well-defined partial
2812 set. Otherwise the high bits are undefined.
2814 This is only really applicable to pseudos, since we just took
2815 care of multi-word hard registers. */
2816 if (((GET_MODE_SIZE (outer_mode
)
2817 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2818 < ((GET_MODE_SIZE (inner_mode
)
2819 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2820 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2823 reg
= SUBREG_REG (reg
);
2827 reg
= SUBREG_REG (reg
);
2834 /* If this set is a MEM, then it kills any aliased writes and any
2835 other MEMs which use it.
2836 If this set is a REG, then it kills any MEMs which use the reg. */
2837 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2839 if (REG_P (reg
) || MEM_P (reg
))
2840 invalidate_mems_from_set (pbi
, reg
);
2842 /* If the memory reference had embedded side effects (autoincrement
2843 address modes) then we may need to kill some entries on the
2845 if (insn
&& MEM_P (reg
))
2846 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2848 if (MEM_P (reg
) && ! side_effects_p (reg
)
2849 /* ??? With more effort we could track conditional memory life. */
2851 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2855 && ! (regno_first
== FRAME_POINTER_REGNUM
2856 && (! reload_completed
|| frame_pointer_needed
))
2857 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2858 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2859 && (! reload_completed
|| frame_pointer_needed
))
2861 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2862 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2866 int some_was_live
= 0, some_was_dead
= 0;
2868 for (i
= regno_first
; i
<= regno_last
; ++i
)
2870 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2873 /* Order of the set operation matters here since both
2874 sets may be the same. */
2875 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2876 if (cond
!= NULL_RTX
2877 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2878 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2880 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2882 if (code
!= CLOBBER
|| needed_regno
)
2883 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2885 some_was_live
|= needed_regno
;
2886 some_was_dead
|= ! needed_regno
;
2889 #ifdef HAVE_conditional_execution
2890 /* Consider conditional death in deciding that the register needs
2892 if (some_was_live
&& ! not_dead
2893 /* The stack pointer is never dead. Well, not strictly true,
2894 but it's very difficult to tell from here. Hopefully
2895 combine_stack_adjustments will fix up the most egregious
2897 && regno_first
!= STACK_POINTER_REGNUM
)
2899 for (i
= regno_first
; i
<= regno_last
; ++i
)
2900 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2901 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2905 /* Additional data to record if this is the final pass. */
2906 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2907 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2910 int blocknum
= pbi
->bb
->index
;
2913 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2915 y
= pbi
->reg_next_use
[regno_first
];
2917 /* The next use is no longer next, since a store intervenes. */
2918 for (i
= regno_first
; i
<= regno_last
; ++i
)
2919 pbi
->reg_next_use
[i
] = 0;
2922 if (flags
& PROP_REG_INFO
)
2924 for (i
= regno_first
; i
<= regno_last
; ++i
)
2926 /* Count (weighted) references, stores, etc. This counts a
2927 register twice if it is modified, but that is correct. */
2928 REG_N_SETS (i
) += 1;
2929 REG_N_REFS (i
) += 1;
2930 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2932 /* The insns where a reg is live are normally counted
2933 elsewhere, but we want the count to include the insn
2934 where the reg is set, and the normal counting mechanism
2935 would not count it. */
2936 REG_LIVE_LENGTH (i
) += 1;
2939 /* If this is a hard reg, record this function uses the reg. */
2940 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2942 for (i
= regno_first
; i
<= regno_last
; i
++)
2943 regs_ever_live
[i
] = 1;
2944 if (flags
& PROP_ASM_SCAN
)
2945 for (i
= regno_first
; i
<= regno_last
; i
++)
2946 regs_asm_clobbered
[i
] = 1;
2950 /* Keep track of which basic blocks each reg appears in. */
2951 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2952 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2953 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2954 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2958 if (! some_was_dead
)
2960 if (flags
& PROP_LOG_LINKS
)
2962 /* Make a logical link from the next following insn
2963 that uses this register, back to this insn.
2964 The following insns have already been processed.
2966 We don't build a LOG_LINK for hard registers containing
2967 in ASM_OPERANDs. If these registers get replaced,
2968 we might wind up changing the semantics of the insn,
2969 even if reload can make what appear to be valid
2972 We don't build a LOG_LINK for global registers to
2973 or from a function call. We don't want to let
2974 combine think that it knows what is going on with
2975 global registers. */
2976 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2977 && (regno_first
>= FIRST_PSEUDO_REGISTER
2978 || (asm_noperands (PATTERN (y
)) < 0
2979 && ! ((CALL_P (insn
)
2981 && global_regs
[regno_first
]))))
2982 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2987 else if (! some_was_live
)
2989 if (flags
& PROP_REG_INFO
)
2990 REG_N_DEATHS (regno_first
) += 1;
2992 if (flags
& PROP_DEATH_NOTES
2994 && (!(flags
& PROP_POST_REGSTACK
)
2995 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
,
3000 /* Note that dead stores have already been deleted
3001 when possible. If we get here, we have found a
3002 dead store that cannot be eliminated (because the
3003 same insn does something useful). Indicate this
3004 by marking the reg being set as dying here. */
3006 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
3011 if (flags
& PROP_DEATH_NOTES
3013 && (!(flags
& PROP_POST_REGSTACK
)
3014 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
,
3019 /* This is a case where we have a multi-word hard register
3020 and some, but not all, of the words of the register are
3021 needed in subsequent insns. Write REG_UNUSED notes
3022 for those parts that were not needed. This case should
3025 for (i
= regno_first
; i
<= regno_last
; ++i
)
3026 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
3028 = alloc_EXPR_LIST (REG_UNUSED
,
3035 /* Mark the register as being dead. */
3037 /* The stack pointer is never dead. Well, not strictly true,
3038 but it's very difficult to tell from here. Hopefully
3039 combine_stack_adjustments will fix up the most egregious
3041 && regno_first
!= STACK_POINTER_REGNUM
)
3043 for (i
= regno_first
; i
<= regno_last
; ++i
)
3044 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
3046 if ((pbi
->flags
& PROP_REG_INFO
)
3047 && REGNO_REG_SET_P (pbi
->reg_live
, i
))
3049 REG_LIVE_LENGTH (i
) += pbi
->insn_num
- reg_deaths
[i
];
3052 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
3054 if (flags
& PROP_DEAD_INSN
)
3055 emit_insn_after (gen_rtx_CLOBBER (VOIDmode
, reg
), insn
);
3058 else if (REG_P (reg
))
3060 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3061 pbi
->reg_next_use
[regno_first
] = 0;
3063 if ((flags
& PROP_REG_INFO
) != 0
3064 && (flags
& PROP_ASM_SCAN
) != 0
3065 && regno_first
< FIRST_PSEUDO_REGISTER
)
3067 for (i
= regno_first
; i
<= regno_last
; i
++)
3068 regs_asm_clobbered
[i
] = 1;
3072 /* If this is the last pass and this is a SCRATCH, show it will be dying
3073 here and count it. */
3074 else if (GET_CODE (reg
) == SCRATCH
)
3076 if (flags
& PROP_DEATH_NOTES
3078 && (!(flags
& PROP_POST_REGSTACK
)
3079 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
, LAST_STACK_REG
))
3083 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
3087 #ifdef HAVE_conditional_execution
3088 /* Mark REGNO conditionally dead.
3089 Return true if the register is now unconditionally dead. */
3092 mark_regno_cond_dead (struct propagate_block_info
*pbi
, int regno
, rtx cond
)
3094 /* If this is a store to a predicate register, the value of the
3095 predicate is changing, we don't know that the predicate as seen
3096 before is the same as that seen after. Flush all dependent
3097 conditions from reg_cond_dead. This will make all such
3098 conditionally live registers unconditionally live. */
3099 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
3100 flush_reg_cond_reg (pbi
, regno
);
3102 /* If this is an unconditional store, remove any conditional
3103 life that may have existed. */
3104 if (cond
== NULL_RTX
)
3105 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
3108 splay_tree_node node
;
3109 struct reg_cond_life_info
*rcli
;
3112 /* Otherwise this is a conditional set. Record that fact.
3113 It may have been conditionally used, or there may be a
3114 subsequent set with a complementary condition. */
3116 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
3119 /* The register was unconditionally live previously.
3120 Record the current condition as the condition under
3121 which it is dead. */
3122 rcli
= XNEW (struct reg_cond_life_info
);
3123 rcli
->condition
= cond
;
3124 rcli
->stores
= cond
;
3125 rcli
->orig_condition
= const0_rtx
;
3126 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
3127 (splay_tree_value
) rcli
);
3129 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3131 /* Not unconditionally dead. */
3136 /* The register was conditionally live previously.
3137 Add the new condition to the old. */
3138 rcli
= (struct reg_cond_life_info
*) node
->value
;
3139 ncond
= rcli
->condition
;
3140 ncond
= ior_reg_cond (ncond
, cond
, 1);
3141 if (rcli
->stores
== const0_rtx
)
3142 rcli
->stores
= cond
;
3143 else if (rcli
->stores
!= const1_rtx
)
3144 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
3146 /* If the register is now unconditionally dead, remove the entry
3147 in the splay_tree. A register is unconditionally dead if the
3148 dead condition ncond is true. A register is also unconditionally
3149 dead if the sum of all conditional stores is an unconditional
3150 store (stores is true), and the dead condition is identically the
3151 same as the original dead condition initialized at the end of
3152 the block. This is a pointer compare, not an rtx_equal_p
3154 if (ncond
== const1_rtx
3155 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
3156 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
3159 rcli
->condition
= ncond
;
3161 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3163 /* Not unconditionally dead. */
3172 /* Called from splay_tree_delete for pbi->reg_cond_life. */
3175 free_reg_cond_life_info (splay_tree_value value
)
3177 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
3181 /* Helper function for flush_reg_cond_reg. */
3184 flush_reg_cond_reg_1 (splay_tree_node node
, void *data
)
3186 struct reg_cond_life_info
*rcli
;
3187 int *xdata
= (int *) data
;
3188 unsigned int regno
= xdata
[0];
3190 /* Don't need to search if last flushed value was farther on in
3191 the in-order traversal. */
3192 if (xdata
[1] >= (int) node
->key
)
3195 /* Splice out portions of the expression that refer to regno. */
3196 rcli
= (struct reg_cond_life_info
*) node
->value
;
3197 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
3198 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
3199 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
3201 /* If the entire condition is now false, signal the node to be removed. */
3202 if (rcli
->condition
== const0_rtx
)
3204 xdata
[1] = node
->key
;
3208 gcc_assert (rcli
->condition
!= const1_rtx
);
3213 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3216 flush_reg_cond_reg (struct propagate_block_info
*pbi
, int regno
)
3222 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3223 flush_reg_cond_reg_1
, pair
) == -1)
3224 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3226 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3229 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3230 For ior/and, the ADD flag determines whether we want to add the new
3231 condition X to the old one unconditionally. If it is zero, we will
3232 only return a new expression if X allows us to simplify part of
3233 OLD, otherwise we return NULL to the caller.
3234 If ADD is nonzero, we will return a new condition in all cases. The
3235 toplevel caller of one of these functions should always pass 1 for
3239 ior_reg_cond (rtx old
, rtx x
, int add
)
3243 if (COMPARISON_P (old
))
3245 if (COMPARISON_P (x
)
3246 && REVERSE_CONDEXEC_PREDICATES_P (x
, old
)
3247 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3249 if (GET_CODE (x
) == GET_CODE (old
)
3250 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3254 return gen_rtx_IOR (0, old
, x
);
3257 switch (GET_CODE (old
))
3260 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3261 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3262 if (op0
!= NULL
|| op1
!= NULL
)
3264 if (op0
== const0_rtx
)
3265 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3266 if (op1
== const0_rtx
)
3267 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3268 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3271 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3272 else if (rtx_equal_p (x
, op0
))
3273 /* (x | A) | x ~ (x | A). */
3276 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3277 else if (rtx_equal_p (x
, op1
))
3278 /* (A | x) | x ~ (A | x). */
3280 return gen_rtx_IOR (0, op0
, op1
);
3284 return gen_rtx_IOR (0, old
, x
);
3287 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3288 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3289 if (op0
!= NULL
|| op1
!= NULL
)
3291 if (op0
== const1_rtx
)
3292 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3293 if (op1
== const1_rtx
)
3294 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3295 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3298 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3299 else if (rtx_equal_p (x
, op0
))
3300 /* (x & A) | x ~ x. */
3303 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3304 else if (rtx_equal_p (x
, op1
))
3305 /* (A & x) | x ~ x. */
3307 return gen_rtx_AND (0, op0
, op1
);
3311 return gen_rtx_IOR (0, old
, x
);
3314 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3316 return not_reg_cond (op0
);
3319 return gen_rtx_IOR (0, old
, x
);
3327 not_reg_cond (rtx x
)
3329 if (x
== const0_rtx
)
3331 else if (x
== const1_rtx
)
3333 if (GET_CODE (x
) == NOT
)
3335 if (COMPARISON_P (x
)
3336 && REG_P (XEXP (x
, 0)))
3338 gcc_assert (XEXP (x
, 1) == const0_rtx
);
3340 return gen_rtx_fmt_ee (reversed_comparison_code (x
, NULL
),
3341 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3343 return gen_rtx_NOT (0, x
);
3347 and_reg_cond (rtx old
, rtx x
, int add
)
3351 if (COMPARISON_P (old
))
3353 if (COMPARISON_P (x
)
3354 && GET_CODE (x
) == reversed_comparison_code (old
, NULL
)
3355 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3357 if (GET_CODE (x
) == GET_CODE (old
)
3358 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3362 return gen_rtx_AND (0, old
, x
);
3365 switch (GET_CODE (old
))
3368 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3369 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3370 if (op0
!= NULL
|| op1
!= NULL
)
3372 if (op0
== const0_rtx
)
3373 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3374 if (op1
== const0_rtx
)
3375 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3376 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3379 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3380 else if (rtx_equal_p (x
, op0
))
3381 /* (x | A) & x ~ x. */
3384 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3385 else if (rtx_equal_p (x
, op1
))
3386 /* (A | x) & x ~ x. */
3388 return gen_rtx_IOR (0, op0
, op1
);
3392 return gen_rtx_AND (0, old
, x
);
3395 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3396 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3397 if (op0
!= NULL
|| op1
!= NULL
)
3399 if (op0
== const1_rtx
)
3400 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3401 if (op1
== const1_rtx
)
3402 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3403 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3406 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3407 else if (rtx_equal_p (x
, op0
))
3408 /* (x & A) & x ~ (x & A). */
3411 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3412 else if (rtx_equal_p (x
, op1
))
3413 /* (A & x) & x ~ (A & x). */
3415 return gen_rtx_AND (0, op0
, op1
);
3419 return gen_rtx_AND (0, old
, x
);
3422 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3424 return not_reg_cond (op0
);
3427 return gen_rtx_AND (0, old
, x
);
3434 /* Given a condition X, remove references to reg REGNO and return the
3435 new condition. The removal will be done so that all conditions
3436 involving REGNO are considered to evaluate to false. This function
3437 is used when the value of REGNO changes. */
3440 elim_reg_cond (rtx x
, unsigned int regno
)
3444 if (COMPARISON_P (x
))
3446 if (REGNO (XEXP (x
, 0)) == regno
)
3451 switch (GET_CODE (x
))
3454 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3455 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3456 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3458 if (op0
== const1_rtx
)
3460 if (op1
== const1_rtx
)
3462 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3464 return gen_rtx_AND (0, op0
, op1
);
3467 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3468 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3469 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3471 if (op0
== const0_rtx
)
3473 if (op1
== const0_rtx
)
3475 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3477 return gen_rtx_IOR (0, op0
, op1
);
3480 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3481 if (op0
== const0_rtx
)
3483 if (op0
== const1_rtx
)
3485 if (op0
!= XEXP (x
, 0))
3486 return not_reg_cond (op0
);
3493 #endif /* HAVE_conditional_execution */
3497 /* Try to substitute the auto-inc expression INC as the address inside
3498 MEM which occurs in INSN. Currently, the address of MEM is an expression
3499 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3500 that has a single set whose source is a PLUS of INCR_REG and something
3504 attempt_auto_inc (struct propagate_block_info
*pbi
, rtx inc
, rtx insn
,
3505 rtx mem
, rtx incr
, rtx incr_reg
)
3507 int regno
= REGNO (incr_reg
);
3508 rtx set
= single_set (incr
);
3509 rtx q
= SET_DEST (set
);
3510 rtx y
= SET_SRC (set
);
3511 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3514 /* Make sure this reg appears only once in this insn. */
3515 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3518 if (dead_or_set_p (incr
, incr_reg
)
3519 /* Mustn't autoinc an eliminable register. */
3520 && (regno
>= FIRST_PSEUDO_REGISTER
3521 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3523 /* This is the simple case. Try to make the auto-inc. If
3524 we can't, we are done. Otherwise, we will do any
3525 needed updates below. */
3526 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3530 /* PREV_INSN used here to check the semi-open interval
3532 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3533 /* We must also check for sets of q as q may be
3534 a call clobbered hard register and there may
3535 be a call between PREV_INSN (insn) and incr. */
3536 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3538 /* We have *p followed sometime later by q = p+size.
3539 Both p and q must be live afterward,
3540 and q is not used between INSN and its assignment.
3541 Change it to q = p, ...*q..., q = q+size.
3542 Then fall into the usual case. */
3546 emit_move_insn (q
, incr_reg
);
3547 insns
= get_insns ();
3550 /* If we can't make the auto-inc, or can't make the
3551 replacement into Y, exit. There's no point in making
3552 the change below if we can't do the auto-inc and doing
3553 so is not correct in the pre-inc case. */
3556 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3557 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3558 if (! apply_change_group ())
3561 /* We now know we'll be doing this change, so emit the
3562 new insn(s) and do the updates. */
3563 emit_insn_before (insns
, insn
);
3565 if (BB_HEAD (pbi
->bb
) == insn
)
3566 BB_HEAD (pbi
->bb
) = insns
;
3568 /* INCR will become a NOTE and INSN won't contain a
3569 use of INCR_REG. If a use of INCR_REG was just placed in
3570 the insn before INSN, make that the next use.
3571 Otherwise, invalidate it. */
3572 if (NONJUMP_INSN_P (PREV_INSN (insn
))
3573 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3574 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3575 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3577 pbi
->reg_next_use
[regno
] = 0;
3582 if ((pbi
->flags
& PROP_REG_INFO
)
3583 && !REGNO_REG_SET_P (pbi
->reg_live
, regno
))
3584 reg_deaths
[regno
] = pbi
->insn_num
;
3586 /* REGNO is now used in INCR which is below INSN, but
3587 it previously wasn't live here. If we don't mark
3588 it as live, we'll put a REG_DEAD note for it
3589 on this insn, which is incorrect. */
3590 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3592 /* If there are any calls between INSN and INCR, show
3593 that REGNO now crosses them. */
3594 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3597 REG_N_CALLS_CROSSED (regno
)++;
3598 if (can_throw_internal (temp
))
3599 REG_N_THROWING_CALLS_CROSSED (regno
)++;
3602 /* Invalidate alias info for Q since we just changed its value. */
3603 clear_reg_alias_info (q
);
3608 /* If we haven't returned, it means we were able to make the
3609 auto-inc, so update the status. First, record that this insn
3610 has an implicit side effect. */
3612 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3614 /* Modify the old increment-insn to simply copy
3615 the already-incremented value of our register. */
3616 changed
= validate_change (incr
, &SET_SRC (set
), incr_reg
, 0);
3617 gcc_assert (changed
);
3619 /* If that makes it a no-op (copying the register into itself) delete
3620 it so it won't appear to be a "use" and a "set" of this
3622 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3624 /* If the original source was dead, it's dead now. */
3627 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3629 remove_note (incr
, note
);
3630 if (XEXP (note
, 0) != incr_reg
)
3632 unsigned int regno
= REGNO (XEXP (note
, 0));
3634 if ((pbi
->flags
& PROP_REG_INFO
)
3635 && REGNO_REG_SET_P (pbi
->reg_live
, regno
))
3637 REG_LIVE_LENGTH (regno
) += pbi
->insn_num
- reg_deaths
[regno
];
3638 reg_deaths
[regno
] = 0;
3640 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3644 SET_INSN_DELETED (incr
);
3647 if (regno
>= FIRST_PSEUDO_REGISTER
)
3649 /* Count an extra reference to the reg. When a reg is
3650 incremented, spilling it is worse, so we want to make
3651 that less likely. */
3652 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3654 /* Count the increment as a setting of the register,
3655 even though it isn't a SET in rtl. */
3656 REG_N_SETS (regno
)++;
3660 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3664 find_auto_inc (struct propagate_block_info
*pbi
, rtx x
, rtx insn
)
3666 rtx addr
= XEXP (x
, 0);
3667 HOST_WIDE_INT offset
= 0;
3668 rtx set
, y
, incr
, inc_val
;
3670 int size
= GET_MODE_SIZE (GET_MODE (x
));
3675 /* Here we detect use of an index register which might be good for
3676 postincrement, postdecrement, preincrement, or predecrement. */
3678 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3679 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3684 regno
= REGNO (addr
);
3686 /* Is the next use an increment that might make auto-increment? */
3687 incr
= pbi
->reg_next_use
[regno
];
3688 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3690 set
= single_set (incr
);
3691 if (set
== 0 || GET_CODE (set
) != SET
)
3695 if (GET_CODE (y
) != PLUS
)
3698 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3699 inc_val
= XEXP (y
, 1);
3700 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3701 inc_val
= XEXP (y
, 0);
3705 if (GET_CODE (inc_val
) == CONST_INT
)
3707 if (HAVE_POST_INCREMENT
3708 && (INTVAL (inc_val
) == size
&& offset
== 0))
3709 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3711 else if (HAVE_POST_DECREMENT
3712 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3713 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3715 else if (HAVE_PRE_INCREMENT
3716 && (INTVAL (inc_val
) == size
&& offset
== size
))
3717 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3719 else if (HAVE_PRE_DECREMENT
3720 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3721 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3723 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3724 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3725 gen_rtx_PLUS (Pmode
,
3728 insn
, x
, incr
, addr
);
3729 else if (HAVE_PRE_MODIFY_DISP
&& offset
== INTVAL (inc_val
))
3730 attempt_auto_inc (pbi
, gen_rtx_PRE_MODIFY (Pmode
, addr
,
3731 gen_rtx_PLUS (Pmode
,
3734 insn
, x
, incr
, addr
);
3736 else if (REG_P (inc_val
)
3737 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3741 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3742 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3743 gen_rtx_PLUS (Pmode
,
3746 insn
, x
, incr
, addr
);
3750 #endif /* AUTO_INC_DEC */
3753 mark_used_reg (struct propagate_block_info
*pbi
, rtx reg
,
3754 rtx cond ATTRIBUTE_UNUSED
, rtx insn
)
3756 unsigned int regno_first
, regno_last
, i
;
3757 int some_was_live
, some_was_dead
, some_not_set
;
3759 regno_last
= regno_first
= REGNO (reg
);
3760 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3761 regno_last
+= hard_regno_nregs
[regno_first
][GET_MODE (reg
)] - 1;
3763 /* Find out if any of this register is live after this instruction. */
3764 some_was_live
= some_was_dead
= 0;
3765 for (i
= regno_first
; i
<= regno_last
; ++i
)
3767 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3768 some_was_live
|= needed_regno
;
3769 some_was_dead
|= ! needed_regno
;
3772 /* Find out if any of the register was set this insn. */
3774 for (i
= regno_first
; i
<= regno_last
; ++i
)
3775 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3777 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3779 /* Record where each reg is used, so when the reg is set we know
3780 the next insn that uses it. */
3781 pbi
->reg_next_use
[regno_first
] = insn
;
3784 if (pbi
->flags
& PROP_REG_INFO
)
3786 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3788 /* If this is a register we are going to try to eliminate,
3789 don't mark it live here. If we are successful in
3790 eliminating it, it need not be live unless it is used for
3791 pseudos, in which case it will have been set live when it
3792 was allocated to the pseudos. If the register will not
3793 be eliminated, reload will set it live at that point.
3795 Otherwise, record that this function uses this register. */
3796 /* ??? The PPC backend tries to "eliminate" on the pic
3797 register to itself. This should be fixed. In the mean
3798 time, hack around it. */
3800 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3801 && (regno_first
== FRAME_POINTER_REGNUM
3802 || regno_first
== ARG_POINTER_REGNUM
)))
3803 for (i
= regno_first
; i
<= regno_last
; ++i
)
3804 regs_ever_live
[i
] = 1;
3808 /* Keep track of which basic block each reg appears in. */
3810 int blocknum
= pbi
->bb
->index
;
3811 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3812 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3813 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3814 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3816 /* Count (weighted) number of uses of each reg. */
3817 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3818 REG_N_REFS (regno_first
)++;
3820 for (i
= regno_first
; i
<= regno_last
; ++i
)
3821 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
3823 gcc_assert (!reg_deaths
[i
]);
3824 reg_deaths
[i
] = pbi
->insn_num
;
3828 /* Record and count the insns in which a reg dies. If it is used in
3829 this insn and was dead below the insn then it dies in this insn.
3830 If it was set in this insn, we do not make a REG_DEAD note;
3831 likewise if we already made such a note. */
3832 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3836 /* Check for the case where the register dying partially
3837 overlaps the register set by this insn. */
3838 if (regno_first
!= regno_last
)
3839 for (i
= regno_first
; i
<= regno_last
; ++i
)
3840 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3842 /* If none of the words in X is needed, make a REG_DEAD note.
3843 Otherwise, we must make partial REG_DEAD notes. */
3844 if (! some_was_live
)
3846 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3848 && (!(pbi
->flags
& PROP_POST_REGSTACK
)
3849 || !IN_RANGE (REGNO (reg
), FIRST_STACK_REG
, LAST_STACK_REG
))
3851 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3853 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3855 if (pbi
->flags
& PROP_REG_INFO
)
3856 REG_N_DEATHS (regno_first
)++;
3860 /* Don't make a REG_DEAD note for a part of a register
3861 that is set in the insn. */
3862 for (i
= regno_first
; i
<= regno_last
; ++i
)
3863 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3864 && ! dead_or_set_regno_p (insn
, i
))
3866 = alloc_EXPR_LIST (REG_DEAD
,
3872 /* Mark the register as being live. */
3873 for (i
= regno_first
; i
<= regno_last
; ++i
)
3875 #ifdef HAVE_conditional_execution
3876 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3879 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3881 #ifdef HAVE_conditional_execution
3882 /* If this is a conditional use, record that fact. If it is later
3883 conditionally set, we'll know to kill the register. */
3884 if (cond
!= NULL_RTX
)
3886 splay_tree_node node
;
3887 struct reg_cond_life_info
*rcli
;
3892 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3895 /* The register was unconditionally live previously.
3896 No need to do anything. */
3900 /* The register was conditionally live previously.
3901 Subtract the new life cond from the old death cond. */
3902 rcli
= (struct reg_cond_life_info
*) node
->value
;
3903 ncond
= rcli
->condition
;
3904 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3906 /* If the register is now unconditionally live,
3907 remove the entry in the splay_tree. */
3908 if (ncond
== const0_rtx
)
3909 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3912 rcli
->condition
= ncond
;
3913 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3914 REGNO (XEXP (cond
, 0)));
3920 /* The register was not previously live at all. Record
3921 the condition under which it is still dead. */
3922 rcli
= XNEW (struct reg_cond_life_info
);
3923 rcli
->condition
= not_reg_cond (cond
);
3924 rcli
->stores
= const0_rtx
;
3925 rcli
->orig_condition
= const0_rtx
;
3926 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3927 (splay_tree_value
) rcli
);
3929 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3932 else if (this_was_live
)
3934 /* The register may have been conditionally live previously, but
3935 is now unconditionally live. Remove it from the conditionally
3936 dead list, so that a conditional set won't cause us to think
3938 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3944 /* Scan expression X for registers which have to be marked used in PBI.
3945 X is considered to be the SET_DEST rtx of SET. TRUE is returned if
3946 X could be handled by this function. */
3949 mark_used_dest_regs (struct propagate_block_info
*pbi
, rtx x
, rtx cond
, rtx insn
)
3952 bool mark_dest
= false;
3955 /* On some platforms calls return values spread over several
3956 locations. These locations are wrapped in a EXPR_LIST rtx
3957 together with a CONST_INT offset. */
3958 if (GET_CODE (x
) == EXPR_LIST
3959 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
3965 /* If storing into MEM, don't show it as being used. But do
3966 show the address as being used. */
3970 if (pbi
->flags
& PROP_AUTOINC
)
3971 find_auto_inc (pbi
, x
, insn
);
3973 mark_used_regs (pbi
, XEXP (x
, 0), cond
, insn
);
3977 /* Storing in STRICT_LOW_PART is like storing in a reg
3978 in that this SET might be dead, so ignore it in TESTREG.
3979 but in some other ways it is like using the reg.
3981 Storing in a SUBREG or a bit field is like storing the entire
3982 register in that if the register's value is not used
3983 then this SET is not needed. */
3984 while (GET_CODE (x
) == STRICT_LOW_PART
3985 || GET_CODE (x
) == ZERO_EXTRACT
3986 || GET_CODE (x
) == SUBREG
)
3988 #ifdef CANNOT_CHANGE_MODE_CLASS
3989 if ((pbi
->flags
& PROP_REG_INFO
) && GET_CODE (x
) == SUBREG
)
3990 record_subregs_of_mode (x
);
3993 /* Modifying a single register in an alternate mode
3994 does not use any of the old value. But these other
3995 ways of storing in a register do use the old value. */
3996 if (GET_CODE (x
) == SUBREG
3997 && !((REG_BYTES (SUBREG_REG (x
))
3998 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
4000 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
4008 /* If this is a store into a register or group of registers,
4009 recursively scan the value being stored. */
4011 && (regno
= REGNO (x
),
4012 !(regno
== FRAME_POINTER_REGNUM
4013 && (!reload_completed
|| frame_pointer_needed
)))
4014 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4015 && !(regno
== HARD_FRAME_POINTER_REGNUM
4016 && (!reload_completed
|| frame_pointer_needed
))
4018 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4019 && !(regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
4024 mark_used_regs (pbi
, dest
, cond
, insn
);
4030 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
4031 This is done assuming the registers needed from X are those that
4032 have 1-bits in PBI->REG_LIVE.
4034 INSN is the containing instruction. If INSN is dead, this function
4038 mark_used_regs (struct propagate_block_info
*pbi
, rtx x
, rtx cond
, rtx insn
)
4041 int flags
= pbi
->flags
;
4046 code
= GET_CODE (x
);
4067 /* If we are clobbering a MEM, mark any registers inside the address
4069 if (MEM_P (XEXP (x
, 0)))
4070 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
4074 /* Don't bother watching stores to mems if this is not the
4075 final pass. We'll not be deleting dead stores this round. */
4076 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
4078 /* Invalidate the data for the last MEM stored, but only if MEM is
4079 something that can be stored into. */
4080 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
4081 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
4082 /* Needn't clear the memory set list. */
4086 rtx temp
= pbi
->mem_set_list
;
4087 rtx prev
= NULL_RTX
;
4092 next
= XEXP (temp
, 1);
4093 if (anti_dependence (XEXP (temp
, 0), x
))
4095 /* Splice temp out of the list. */
4097 XEXP (prev
, 1) = next
;
4099 pbi
->mem_set_list
= next
;
4100 free_EXPR_LIST_node (temp
);
4101 pbi
->mem_set_list_len
--;
4109 /* If the memory reference had embedded side effects (autoincrement
4110 address modes. Then we may need to kill some entries on the
4113 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
4117 if (flags
& PROP_AUTOINC
)
4118 find_auto_inc (pbi
, x
, insn
);
4123 #ifdef CANNOT_CHANGE_MODE_CLASS
4124 if (flags
& PROP_REG_INFO
)
4125 record_subregs_of_mode (x
);
4128 /* While we're here, optimize this case. */
4135 /* See a register other than being set => mark it as needed. */
4136 mark_used_reg (pbi
, x
, cond
, insn
);
4141 rtx dest
= SET_DEST (x
);
4145 if (GET_CODE (dest
) == PARALLEL
)
4146 for (i
= 0; i
< XVECLEN (dest
, 0); i
++)
4147 ret
|= mark_used_dest_regs (pbi
, XVECEXP (dest
, 0, i
), cond
, insn
);
4149 ret
= mark_used_dest_regs (pbi
, dest
, cond
, insn
);
4153 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
4160 case UNSPEC_VOLATILE
:
4164 /* Traditional and volatile asm instructions must be considered to use
4165 and clobber all hard registers, all pseudo-registers and all of
4166 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
4168 Consider for instance a volatile asm that changes the fpu rounding
4169 mode. An insn should not be moved across this even if it only uses
4170 pseudo-regs because it might give an incorrectly rounded result.
4172 ?!? Unfortunately, marking all hard registers as live causes massive
4173 problems for the register allocator and marking all pseudos as live
4174 creates mountains of uninitialized variable warnings.
4176 So for now, just clear the memory set list and mark any regs
4177 we can find in ASM_OPERANDS as used. */
4178 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
4180 free_EXPR_LIST_list (&pbi
->mem_set_list
);
4181 pbi
->mem_set_list_len
= 0;
4184 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
4185 We can not just fall through here since then we would be confused
4186 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
4187 traditional asms unlike their normal usage. */
4188 if (code
== ASM_OPERANDS
)
4192 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
4193 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
4201 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
4203 cond
= COND_EXEC_TEST (x
);
4204 x
= COND_EXEC_CODE (x
);
4211 /* Recursively scan the operands of this expression. */
4214 const char * const fmt
= GET_RTX_FORMAT (code
);
4217 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4221 /* Tail recursive case: save a function call level. */
4227 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
4229 else if (fmt
[i
] == 'E')
4232 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4233 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4242 try_pre_increment_1 (struct propagate_block_info
*pbi
, rtx insn
)
4244 /* Find the next use of this reg. If in same basic block,
4245 make it do pre-increment or pre-decrement if appropriate. */
4246 rtx x
= single_set (insn
);
4247 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4248 * INTVAL (XEXP (SET_SRC (x
), 1)));
4249 int regno
= REGNO (SET_DEST (x
));
4250 rtx y
= pbi
->reg_next_use
[regno
];
4252 && SET_DEST (x
) != stack_pointer_rtx
4253 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4254 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4255 mode would be better. */
4256 && ! dead_or_set_p (y
, SET_DEST (x
))
4257 && try_pre_increment (y
, SET_DEST (x
), amount
))
4259 /* We have found a suitable auto-increment and already changed
4260 insn Y to do it. So flush this increment instruction. */
4261 propagate_block_delete_insn (insn
);
4263 /* Count a reference to this reg for the increment insn we are
4264 deleting. When a reg is incremented, spilling it is worse,
4265 so we want to make that less likely. */
4266 if (regno
>= FIRST_PSEUDO_REGISTER
)
4268 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4269 REG_N_SETS (regno
)++;
4272 /* Flush any remembered memories depending on the value of
4273 the incremented register. */
4274 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4281 /* Try to change INSN so that it does pre-increment or pre-decrement
4282 addressing on register REG in order to add AMOUNT to REG.
4283 AMOUNT is negative for pre-decrement.
4284 Returns 1 if the change could be made.
4285 This checks all about the validity of the result of modifying INSN. */
4288 try_pre_increment (rtx insn
, rtx reg
, HOST_WIDE_INT amount
)
4292 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4293 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4295 /* Nonzero if we can try to make a post-increment or post-decrement.
4296 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4297 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4298 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4301 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4304 /* From the sign of increment, see which possibilities are conceivable
4305 on this target machine. */
4306 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4308 if (HAVE_POST_INCREMENT
&& amount
> 0)
4311 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4313 if (HAVE_POST_DECREMENT
&& amount
< 0)
4316 if (! (pre_ok
|| post_ok
))
4319 /* It is not safe to add a side effect to a jump insn
4320 because if the incremented register is spilled and must be reloaded
4321 there would be no way to store the incremented value back in memory. */
4328 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4329 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4331 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4335 if (use
== 0 || use
== (rtx
) (size_t) 1)
4338 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4341 /* See if this combination of instruction and addressing mode exists. */
4342 if (! validate_change (insn
, &XEXP (use
, 0),
4343 gen_rtx_fmt_e (amount
> 0
4344 ? (do_post
? POST_INC
: PRE_INC
)
4345 : (do_post
? POST_DEC
: PRE_DEC
),
4349 /* Record that this insn now has an implicit side effect on X. */
4350 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4354 #endif /* AUTO_INC_DEC */
4356 /* Find the place in the rtx X where REG is used as a memory address.
4357 Return the MEM rtx that so uses it.
4358 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4359 (plus REG (const_int PLUSCONST)).
4361 If such an address does not appear, return 0.
4362 If REG appears more than once, or is used other than in such an address,
4366 find_use_as_address (rtx x
, rtx reg
, HOST_WIDE_INT plusconst
)
4368 enum rtx_code code
= GET_CODE (x
);
4369 const char * const fmt
= GET_RTX_FORMAT (code
);
4374 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4377 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4378 && XEXP (XEXP (x
, 0), 0) == reg
4379 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4380 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4383 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4385 /* If REG occurs inside a MEM used in a bit-field reference,
4386 that is unacceptable. */
4387 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4388 return (rtx
) (size_t) 1;
4392 return (rtx
) (size_t) 1;
4394 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4398 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4402 return (rtx
) (size_t) 1;
4404 else if (fmt
[i
] == 'E')
4407 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4409 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4413 return (rtx
) (size_t) 1;
4421 /* Write information about registers and basic blocks into FILE.
4422 This is part of making a debugging dump. */
4425 dump_regset (regset r
, FILE *outf
)
4428 reg_set_iterator rsi
;
4432 fputs (" (nil)", outf
);
4436 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
, rsi
)
4438 fprintf (outf
, " %d", i
);
4439 if (i
< FIRST_PSEUDO_REGISTER
)
4440 fprintf (outf
, " [%s]",
4445 /* Print a human-readable representation of R on the standard error
4446 stream. This function is designed to be used from within the
4450 debug_regset (regset r
)
4452 dump_regset (r
, stderr
);
4453 putc ('\n', stderr
);
4456 /* Recompute register set/reference counts immediately prior to register
4459 This avoids problems with set/reference counts changing to/from values
4460 which have special meanings to the register allocators.
4462 Additionally, the reference counts are the primary component used by the
4463 register allocators to prioritize pseudos for allocation to hard regs.
4464 More accurate reference counts generally lead to better register allocation.
4466 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4467 possibly other information which is used by the register allocators. */
4470 recompute_reg_usage (void)
4472 allocate_reg_life_data ();
4473 /* distribute_notes in combiner fails to convert some of the
4474 REG_UNUSED notes to REG_DEAD notes. This causes CHECK_DEAD_NOTES
4475 in sched1 to die. To solve this update the DEATH_NOTES
4477 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
| PROP_DEATH_NOTES
);
4480 dump_flow_info (dump_file
, dump_flags
);
4484 struct tree_opt_pass pass_recompute_reg_usage
=
4488 recompute_reg_usage
, /* execute */
4491 0, /* static_pass_number */
4493 0, /* properties_required */
4494 0, /* properties_provided */
4495 0, /* properties_destroyed */
4496 0, /* todo_flags_start */
4497 TODO_dump_func
, /* todo_flags_finish */
4501 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4502 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4503 of the number of registers that died.
4504 If KILL is 1, remove old REG_DEAD / REG_UNUSED notes. If it is 0, don't.
4505 if it is -1, remove them unless they pertain to a stack reg. */
4508 count_or_remove_death_notes (sbitmap blocks
, int kill
)
4514 /* This used to be a loop over all the blocks with a membership test
4515 inside the loop. That can be amazingly expensive on a large CFG
4516 when only a small number of bits are set in BLOCKs (for example,
4517 the calls from the scheduler typically have very few bits set).
4519 For extra credit, someone should convert BLOCKS to a bitmap rather
4523 sbitmap_iterator sbi
;
4525 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
, sbi
)
4527 basic_block bb
= BASIC_BLOCK (i
);
4528 /* The bitmap may be flawed in that one of the basic blocks
4529 may have been deleted before you get here. */
4531 count
+= count_or_remove_death_notes_bb (bb
, kill
);
4538 count
+= count_or_remove_death_notes_bb (bb
, kill
);
4545 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from basic
4546 block BB. Returns a count of the number of registers that died. */
4549 count_or_remove_death_notes_bb (basic_block bb
, int kill
)
4554 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
4558 rtx
*pprev
= ®_NOTES (insn
);
4563 switch (REG_NOTE_KIND (link
))
4566 if (REG_P (XEXP (link
, 0)))
4568 rtx reg
= XEXP (link
, 0);
4571 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4574 n
= hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)];
4584 && (!REG_P (XEXP (link
, 0))
4585 || !IN_RANGE (REGNO (XEXP (link
, 0)),
4586 FIRST_STACK_REG
, LAST_STACK_REG
))
4590 rtx next
= XEXP (link
, 1);
4591 free_EXPR_LIST_node (link
);
4592 *pprev
= link
= next
;
4598 pprev
= &XEXP (link
, 1);
4605 if (insn
== BB_END (bb
))
4612 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4613 if blocks is NULL. */
4616 clear_log_links (sbitmap blocks
)
4622 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4624 free_INSN_LIST_list (&LOG_LINKS (insn
));
4629 sbitmap_iterator sbi
;
4631 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
, sbi
)
4633 basic_block bb
= BASIC_BLOCK (i
);
4635 for (insn
= BB_HEAD (bb
); insn
!= NEXT_INSN (BB_END (bb
));
4636 insn
= NEXT_INSN (insn
))
4638 free_INSN_LIST_list (&LOG_LINKS (insn
));
4643 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4644 correspond to the hard registers, if any, set in that map. This
4645 could be done far more efficiently by having all sorts of special-cases
4646 with moving single words, but probably isn't worth the trouble. */
4649 reg_set_to_hard_reg_set (HARD_REG_SET
*to
, bitmap from
)
4654 EXECUTE_IF_SET_IN_BITMAP (from
, 0, i
, bi
)
4656 if (i
>= FIRST_PSEUDO_REGISTER
)
4658 SET_HARD_REG_BIT (*to
, i
);
4664 gate_remove_death_notes (void)
4666 return flag_profile_values
;
4670 rest_of_handle_remove_death_notes (void)
4672 count_or_remove_death_notes (NULL
, 1);
4676 struct tree_opt_pass pass_remove_death_notes
=
4678 "ednotes", /* name */
4679 gate_remove_death_notes
, /* gate */
4680 rest_of_handle_remove_death_notes
, /* execute */
4683 0, /* static_pass_number */
4685 0, /* properties_required */
4686 0, /* properties_provided */
4687 0, /* properties_destroyed */
4688 0, /* todo_flags_start */
4689 0, /* todo_flags_finish */
4693 /* Perform life analysis. */
4695 rest_of_handle_life (void)
4699 life_analysis (PROP_FINAL
);
4701 cleanup_cfg (CLEANUP_EXPENSIVE
| CLEANUP_UPDATE_LIFE
| CLEANUP_LOG_LINKS
4702 | (flag_thread_jumps
? CLEANUP_THREADING
: 0));
4706 setjmp_vars_warning (DECL_INITIAL (current_function_decl
));
4707 setjmp_args_warning ();
4712 if (initialize_uninitialized_subregs ())
4714 /* Insns were inserted, and possibly pseudos created, so
4715 things might look a bit different. */
4716 allocate_reg_life_data ();
4717 update_life_info (NULL
, UPDATE_LIFE_GLOBAL_RM_NOTES
,
4718 PROP_LOG_LINKS
| PROP_REG_INFO
| PROP_DEATH_NOTES
);
4726 struct tree_opt_pass pass_life
=
4730 rest_of_handle_life
, /* execute */
4733 0, /* static_pass_number */
4734 TV_FLOW
, /* tv_id */
4735 0, /* properties_required */
4736 0, /* properties_provided */
4737 0, /* properties_destroyed */
4738 TODO_verify_flow
, /* todo_flags_start */
4740 TODO_ggc_collect
, /* todo_flags_finish */
4745 rest_of_handle_flow2 (void)
4747 /* If optimizing, then go ahead and split insns now. */
4751 split_all_insns (0);
4753 if (flag_branch_target_load_optimize
)
4754 branch_target_load_optimize (epilogue_completed
);
4757 cleanup_cfg (CLEANUP_EXPENSIVE
);
4759 /* On some machines, the prologue and epilogue code, or parts thereof,
4760 can be represented as RTL. Doing so lets us schedule insns between
4761 it and the rest of the code and also allows delayed branch
4762 scheduling to operate in the epilogue. */
4763 thread_prologue_and_epilogue_insns (get_insns ());
4764 epilogue_completed
= 1;
4765 flow2_completed
= 1;
4769 struct tree_opt_pass pass_flow2
=
4773 rest_of_handle_flow2
, /* execute */
4776 0, /* static_pass_number */
4777 TV_FLOW2
, /* tv_id */
4778 0, /* properties_required */
4779 0, /* properties_provided */
4780 0, /* properties_destroyed */
4781 TODO_verify_flow
, /* todo_flags_start */
4783 TODO_ggc_collect
, /* todo_flags_finish */