1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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 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 (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #define EH_USES(REGNO) 0
174 #ifdef HAVE_conditional_execution
175 #ifndef REVERSE_CONDEXEC_PREDICATES_P
176 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
180 /* Nonzero if the second flow pass has completed. */
183 /* Maximum register number used in this function, plus one. */
187 /* Indexed by n, giving various register information */
189 varray_type reg_n_info
;
191 /* Size of a regset for the current function,
192 in (1) bytes and (2) elements. */
197 /* Regset of regs live when calls to `setjmp'-like functions happen. */
198 /* ??? Does this exist only for the setjmp-clobbered warning message? */
200 regset regs_live_at_setjmp
;
202 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
203 that have to go in the same hard reg.
204 The first two regs in the list are a pair, and the next two
205 are another pair, etc. */
208 /* Callback that determines if it's ok for a function to have no
209 noreturn attribute. */
210 int (*lang_missing_noreturn_ok_p
) PARAMS ((tree
));
212 /* Set of registers that may be eliminable. These are handled specially
213 in updating regs_ever_live. */
215 static HARD_REG_SET elim_reg_set
;
217 /* Holds information for tracking conditional register life information. */
218 struct reg_cond_life_info
220 /* A boolean expression of conditions under which a register is dead. */
222 /* Conditions under which a register is dead at the basic block end. */
225 /* A boolean expression of conditions under which a register has been
229 /* ??? Could store mask of bytes that are dead, so that we could finally
230 track lifetimes of multi-word registers accessed via subregs. */
233 /* For use in communicating between propagate_block and its subroutines.
234 Holds all information needed to compute life and def-use information. */
236 struct propagate_block_info
238 /* The basic block we're considering. */
241 /* Bit N is set if register N is conditionally or unconditionally live. */
244 /* Bit N is set if register N is set this insn. */
247 /* Element N is the next insn that uses (hard or pseudo) register N
248 within the current basic block; or zero, if there is no such insn. */
251 /* Contains a list of all the MEMs we are tracking for dead store
255 /* If non-null, record the set of registers set unconditionally in the
259 /* If non-null, record the set of registers set conditionally in the
261 regset cond_local_set
;
263 #ifdef HAVE_conditional_execution
264 /* Indexed by register number, holds a reg_cond_life_info for each
265 register that is not unconditionally live or dead. */
266 splay_tree reg_cond_dead
;
268 /* Bit N is set if register N is in an expression in reg_cond_dead. */
272 /* The length of mem_set_list. */
273 int mem_set_list_len
;
275 /* Non-zero if the value of CC0 is live. */
278 /* Flags controling the set of information propagate_block collects. */
282 /* Number of dead insns removed. */
285 /* Maximum length of pbi->mem_set_list before we start dropping
286 new elements on the floor. */
287 #define MAX_MEM_SET_LIST_LEN 100
289 /* Forward declarations */
290 static int verify_wide_reg_1
PARAMS ((rtx
*, void *));
291 static void verify_wide_reg
PARAMS ((int, basic_block
));
292 static void verify_local_live_at_start
PARAMS ((regset
, basic_block
));
293 static void notice_stack_pointer_modification_1
PARAMS ((rtx
, rtx
, void *));
294 static void notice_stack_pointer_modification
PARAMS ((rtx
));
295 static void mark_reg
PARAMS ((rtx
, void *));
296 static void mark_regs_live_at_end
PARAMS ((regset
));
297 static int set_phi_alternative_reg
PARAMS ((rtx
, int, int, void *));
298 static void calculate_global_regs_live
PARAMS ((sbitmap
, sbitmap
, int));
299 static void propagate_block_delete_insn
PARAMS ((rtx
));
300 static rtx propagate_block_delete_libcall
PARAMS ((rtx
, rtx
));
301 static int insn_dead_p
PARAMS ((struct propagate_block_info
*,
303 static int libcall_dead_p
PARAMS ((struct propagate_block_info
*,
305 static void mark_set_regs
PARAMS ((struct propagate_block_info
*,
307 static void mark_set_1
PARAMS ((struct propagate_block_info
*,
308 enum rtx_code
, rtx
, rtx
,
310 static int find_regno_partial
PARAMS ((rtx
*, void *));
312 #ifdef HAVE_conditional_execution
313 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
315 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
316 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
317 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
319 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
320 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
321 static rtx not_reg_cond
PARAMS ((rtx
));
322 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
325 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
326 rtx
, rtx
, rtx
, rtx
, rtx
));
327 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
329 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
331 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
333 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
335 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
337 void dump_flow_info
PARAMS ((FILE *));
338 void debug_flow_info
PARAMS ((void));
339 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
341 static int invalidate_mems_from_autoinc
PARAMS ((rtx
*, void *));
342 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
344 static void clear_log_links
PARAMS ((sbitmap
));
348 check_function_return_warnings ()
350 if (warn_missing_noreturn
351 && !TREE_THIS_VOLATILE (cfun
->decl
)
352 && EXIT_BLOCK_PTR
->pred
== NULL
353 && (lang_missing_noreturn_ok_p
354 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
355 warning ("function might be possible candidate for attribute `noreturn'");
357 /* If we have a path to EXIT, then we do return. */
358 if (TREE_THIS_VOLATILE (cfun
->decl
)
359 && EXIT_BLOCK_PTR
->pred
!= NULL
)
360 warning ("`noreturn' function does return");
362 /* If the clobber_return_insn appears in some basic block, then we
363 do reach the end without returning a value. */
364 else if (warn_return_type
365 && cfun
->x_clobber_return_insn
!= NULL
366 && EXIT_BLOCK_PTR
->pred
!= NULL
)
368 int max_uid
= get_max_uid ();
370 /* If clobber_return_insn was excised by jump1, then renumber_insns
371 can make max_uid smaller than the number still recorded in our rtx.
372 That's fine, since this is a quick way of verifying that the insn
373 is no longer in the chain. */
374 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
378 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
379 if (insn
== cfun
->x_clobber_return_insn
)
381 warning ("control reaches end of non-void function");
388 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
389 note associated with the BLOCK. */
392 first_insn_after_basic_block_note (block
)
397 /* Get the first instruction in the block. */
400 if (insn
== NULL_RTX
)
402 if (GET_CODE (insn
) == CODE_LABEL
)
403 insn
= NEXT_INSN (insn
);
404 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
407 return NEXT_INSN (insn
);
410 /* Perform data flow analysis.
411 F is the first insn of the function; FLAGS is a set of PROP_* flags
412 to be used in accumulating flow info. */
415 life_analysis (f
, file
, flags
)
420 #ifdef ELIMINABLE_REGS
422 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
425 /* Record which registers will be eliminated. We use this in
428 CLEAR_HARD_REG_SET (elim_reg_set
);
430 #ifdef ELIMINABLE_REGS
431 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
432 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
434 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
438 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
440 /* The post-reload life analysis have (on a global basis) the same
441 registers live as was computed by reload itself. elimination
442 Otherwise offsets and such may be incorrect.
444 Reload will make some registers as live even though they do not
447 We don't want to create new auto-incs after reload, since they
448 are unlikely to be useful and can cause problems with shared
450 if (reload_completed
)
451 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
453 /* We want alias analysis information for local dead store elimination. */
454 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
455 init_alias_analysis ();
457 /* Always remove no-op moves. Do this before other processing so
458 that we don't have to keep re-scanning them. */
459 delete_noop_moves (f
);
461 /* Some targets can emit simpler epilogues if they know that sp was
462 not ever modified during the function. After reload, of course,
463 we've already emitted the epilogue so there's no sense searching. */
464 if (! reload_completed
)
465 notice_stack_pointer_modification (f
);
467 /* Allocate and zero out data structures that will record the
468 data from lifetime analysis. */
469 allocate_reg_life_data ();
470 allocate_bb_life_data ();
472 /* Find the set of registers live on function exit. */
473 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
475 /* "Update" life info from zero. It'd be nice to begin the
476 relaxation with just the exit and noreturn blocks, but that set
477 is not immediately handy. */
479 if (flags
& PROP_REG_INFO
)
480 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
481 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
484 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
485 end_alias_analysis ();
488 dump_flow_info (file
);
490 free_basic_block_vars (1);
492 /* Removing dead insns should've made jumptables really dead. */
493 delete_dead_jumptables ();
496 /* A subroutine of verify_wide_reg, called through for_each_rtx.
497 Search for REGNO. If found, return 2 if it is not wider than
501 verify_wide_reg_1 (px
, pregno
)
506 unsigned int regno
= *(int *) pregno
;
508 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
510 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
517 /* A subroutine of verify_local_live_at_start. Search through insns
518 of BB looking for register REGNO. */
521 verify_wide_reg (regno
, bb
)
525 rtx head
= bb
->head
, end
= bb
->end
;
531 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
539 head
= NEXT_INSN (head
);
544 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
545 dump_bb (bb
, rtl_dump_file
);
550 /* A subroutine of update_life_info. Verify that there are no untoward
551 changes in live_at_start during a local update. */
554 verify_local_live_at_start (new_live_at_start
, bb
)
555 regset new_live_at_start
;
558 if (reload_completed
)
560 /* After reload, there are no pseudos, nor subregs of multi-word
561 registers. The regsets should exactly match. */
562 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
566 fprintf (rtl_dump_file
,
567 "live_at_start mismatch in bb %d, aborting\nNew:\n",
569 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
570 fputs ("Old:\n", rtl_dump_file
);
571 dump_bb (bb
, rtl_dump_file
);
580 /* Find the set of changed registers. */
581 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
583 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
585 /* No registers should die. */
586 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
590 fprintf (rtl_dump_file
,
591 "Register %d died unexpectedly.\n", i
);
592 dump_bb (bb
, rtl_dump_file
);
597 /* Verify that the now-live register is wider than word_mode. */
598 verify_wide_reg (i
, bb
);
603 /* Updates life information starting with the basic blocks set in BLOCKS.
604 If BLOCKS is null, consider it to be the universal set.
606 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
607 we are only expecting local modifications to basic blocks. If we find
608 extra registers live at the beginning of a block, then we either killed
609 useful data, or we have a broken split that wants data not provided.
610 If we find registers removed from live_at_start, that means we have
611 a broken peephole that is killing a register it shouldn't.
613 ??? This is not true in one situation -- when a pre-reload splitter
614 generates subregs of a multi-word pseudo, current life analysis will
615 lose the kill. So we _can_ have a pseudo go live. How irritating.
617 Including PROP_REG_INFO does not properly refresh regs_ever_live
618 unless the caller resets it to zero. */
621 update_life_info (blocks
, extent
, prop_flags
)
623 enum update_life_extent extent
;
627 regset_head tmp_head
;
629 int stabilized_prop_flags
= prop_flags
;
632 tmp
= INITIALIZE_REG_SET (tmp_head
);
635 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
636 ? TV_LIFE_UPDATE
: TV_LIFE
);
638 /* Changes to the CFG are only allowed when
639 doing a global update for the entire CFG. */
640 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
641 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
644 /* For a global update, we go through the relaxation process again. */
645 if (extent
!= UPDATE_LIFE_LOCAL
)
651 calculate_global_regs_live (blocks
, blocks
,
652 prop_flags
& (PROP_SCAN_DEAD_CODE
653 | PROP_SCAN_DEAD_STORES
654 | PROP_ALLOW_CFG_CHANGES
));
656 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
657 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
660 /* Removing dead code may allow the CFG to be simplified which
661 in turn may allow for further dead code detection / removal. */
662 FOR_EACH_BB_REVERSE (bb
)
664 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
665 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
666 prop_flags
& (PROP_SCAN_DEAD_CODE
667 | PROP_SCAN_DEAD_STORES
668 | PROP_KILL_DEAD_CODE
));
671 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
672 subsequent propagate_block calls, since removing or acting as
673 removing dead code can affect global register liveness, which
674 is supposed to be finalized for this call after this loop. */
675 stabilized_prop_flags
676 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
677 | PROP_KILL_DEAD_CODE
);
682 /* We repeat regardless of what cleanup_cfg says. If there were
683 instructions deleted above, that might have been only a
684 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
685 Further improvement may be possible. */
686 cleanup_cfg (CLEANUP_EXPENSIVE
);
689 /* If asked, remove notes from the blocks we'll update. */
690 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
691 count_or_remove_death_notes (blocks
, 1);
694 /* Clear log links in case we are asked to (re)compute them. */
695 if (prop_flags
& PROP_LOG_LINKS
)
696 clear_log_links (blocks
);
700 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
702 bb
= BASIC_BLOCK (i
);
704 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
705 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
707 if (extent
== UPDATE_LIFE_LOCAL
)
708 verify_local_live_at_start (tmp
, bb
);
713 FOR_EACH_BB_REVERSE (bb
)
715 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
717 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
719 if (extent
== UPDATE_LIFE_LOCAL
)
720 verify_local_live_at_start (tmp
, bb
);
726 if (prop_flags
& PROP_REG_INFO
)
728 /* The only pseudos that are live at the beginning of the function
729 are those that were not set anywhere in the function. local-alloc
730 doesn't know how to handle these correctly, so mark them as not
731 local to any one basic block. */
732 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
733 FIRST_PSEUDO_REGISTER
, i
,
734 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
736 /* We have a problem with any pseudoreg that lives across the setjmp.
737 ANSI says that if a user variable does not change in value between
738 the setjmp and the longjmp, then the longjmp preserves it. This
739 includes longjmp from a place where the pseudo appears dead.
740 (In principle, the value still exists if it is in scope.)
741 If the pseudo goes in a hard reg, some other value may occupy
742 that hard reg where this pseudo is dead, thus clobbering the pseudo.
743 Conclusion: such a pseudo must not go in a hard reg. */
744 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
745 FIRST_PSEUDO_REGISTER
, i
,
747 if (regno_reg_rtx
[i
] != 0)
749 REG_LIVE_LENGTH (i
) = -1;
750 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
754 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
755 ? TV_LIFE_UPDATE
: TV_LIFE
);
756 if (ndead
&& rtl_dump_file
)
757 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
761 /* Update life information in all blocks where BB_DIRTY is set. */
764 update_life_info_in_dirty_blocks (extent
, prop_flags
)
765 enum update_life_extent extent
;
768 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
773 sbitmap_zero (update_life_blocks
);
776 if (extent
== UPDATE_LIFE_LOCAL
)
778 if (bb
->flags
& BB_DIRTY
)
780 SET_BIT (update_life_blocks
, bb
->index
);
786 /* ??? Bootstrap with -march=pentium4 fails to terminate
787 with only a partial life update. */
788 SET_BIT (update_life_blocks
, bb
->index
);
789 if (bb
->flags
& BB_DIRTY
)
795 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
797 sbitmap_free (update_life_blocks
);
801 /* Free the variables allocated by find_basic_blocks.
803 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
806 free_basic_block_vars (keep_head_end_p
)
809 if (! keep_head_end_p
)
811 if (basic_block_info
)
814 VARRAY_FREE (basic_block_info
);
817 last_basic_block
= 0;
819 ENTRY_BLOCK_PTR
->aux
= NULL
;
820 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
821 EXIT_BLOCK_PTR
->aux
= NULL
;
822 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
826 /* Delete any insns that copy a register to itself. */
829 delete_noop_moves (f
)
830 rtx f ATTRIBUTE_UNUSED
;
838 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
840 next
= NEXT_INSN (insn
);
841 if (INSN_P (insn
) && noop_move_p (insn
))
845 /* If we're about to remove the first insn of a libcall
846 then move the libcall note to the next real insn and
847 update the retval note. */
848 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
849 && XEXP (note
, 0) != insn
)
851 rtx new_libcall_insn
= next_real_insn (insn
);
852 rtx retval_note
= find_reg_note (XEXP (note
, 0),
853 REG_RETVAL
, NULL_RTX
);
854 REG_NOTES (new_libcall_insn
)
855 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
856 REG_NOTES (new_libcall_insn
));
857 XEXP (retval_note
, 0) = new_libcall_insn
;
860 delete_insn_and_edges (insn
);
865 if (nnoops
&& rtl_dump_file
)
866 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
870 /* Delete any jump tables never referenced. We can't delete them at the
871 time of removing tablejump insn as they are referenced by the preceding
872 insns computing the destination, so we delay deleting and garbagecollect
873 them once life information is computed. */
875 delete_dead_jumptables ()
878 for (insn
= get_insns (); insn
; insn
= next
)
880 next
= NEXT_INSN (insn
);
881 if (GET_CODE (insn
) == CODE_LABEL
882 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
883 && GET_CODE (next
) == JUMP_INSN
884 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
885 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
888 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
889 delete_insn (NEXT_INSN (insn
));
891 next
= NEXT_INSN (next
);
896 /* Determine if the stack pointer is constant over the life of the function.
897 Only useful before prologues have been emitted. */
900 notice_stack_pointer_modification_1 (x
, pat
, data
)
902 rtx pat ATTRIBUTE_UNUSED
;
903 void *data ATTRIBUTE_UNUSED
;
905 if (x
== stack_pointer_rtx
906 /* The stack pointer is only modified indirectly as the result
907 of a push until later in flow. See the comments in rtl.texi
908 regarding Embedded Side-Effects on Addresses. */
909 || (GET_CODE (x
) == MEM
910 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
911 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
912 current_function_sp_is_unchanging
= 0;
916 notice_stack_pointer_modification (f
)
921 /* Assume that the stack pointer is unchanging if alloca hasn't
923 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
924 if (! current_function_sp_is_unchanging
)
927 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
931 /* Check if insn modifies the stack pointer. */
932 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
934 if (! current_function_sp_is_unchanging
)
940 /* Mark a register in SET. Hard registers in large modes get all
941 of their component registers set as well. */
948 regset set
= (regset
) xset
;
949 int regno
= REGNO (reg
);
951 if (GET_MODE (reg
) == BLKmode
)
954 SET_REGNO_REG_SET (set
, regno
);
955 if (regno
< FIRST_PSEUDO_REGISTER
)
957 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
959 SET_REGNO_REG_SET (set
, regno
+ n
);
963 /* Mark those regs which are needed at the end of the function as live
964 at the end of the last basic block. */
967 mark_regs_live_at_end (set
)
972 /* If exiting needs the right stack value, consider the stack pointer
973 live at the end of the function. */
974 if ((HAVE_epilogue
&& reload_completed
)
975 || ! EXIT_IGNORE_STACK
976 || (! FRAME_POINTER_REQUIRED
977 && ! current_function_calls_alloca
978 && flag_omit_frame_pointer
)
979 || current_function_sp_is_unchanging
)
981 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
984 /* Mark the frame pointer if needed at the end of the function. If
985 we end up eliminating it, it will be removed from the live list
986 of each basic block by reload. */
988 if (! reload_completed
|| frame_pointer_needed
)
990 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
991 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
992 /* If they are different, also mark the hard frame pointer as live. */
993 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
994 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
998 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
999 /* Many architectures have a GP register even without flag_pic.
1000 Assume the pic register is not in use, or will be handled by
1001 other means, if it is not fixed. */
1002 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1003 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1004 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1007 /* Mark all global registers, and all registers used by the epilogue
1008 as being live at the end of the function since they may be
1009 referenced by our caller. */
1010 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1011 if (global_regs
[i
] || EPILOGUE_USES (i
))
1012 SET_REGNO_REG_SET (set
, i
);
1014 if (HAVE_epilogue
&& reload_completed
)
1016 /* Mark all call-saved registers that we actually used. */
1017 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1018 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1019 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1020 SET_REGNO_REG_SET (set
, i
);
1023 #ifdef EH_RETURN_DATA_REGNO
1024 /* Mark the registers that will contain data for the handler. */
1025 if (reload_completed
&& current_function_calls_eh_return
)
1028 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1029 if (regno
== INVALID_REGNUM
)
1031 SET_REGNO_REG_SET (set
, regno
);
1034 #ifdef EH_RETURN_STACKADJ_RTX
1035 if ((! HAVE_epilogue
|| ! reload_completed
)
1036 && current_function_calls_eh_return
)
1038 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1039 if (tmp
&& REG_P (tmp
))
1040 mark_reg (tmp
, set
);
1043 #ifdef EH_RETURN_HANDLER_RTX
1044 if ((! HAVE_epilogue
|| ! reload_completed
)
1045 && current_function_calls_eh_return
)
1047 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1048 if (tmp
&& REG_P (tmp
))
1049 mark_reg (tmp
, set
);
1053 /* Mark function return value. */
1054 diddle_return_value (mark_reg
, set
);
1057 /* Callback function for for_each_successor_phi. DATA is a regset.
1058 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1059 INSN, in the regset. */
1062 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1063 rtx insn ATTRIBUTE_UNUSED
;
1064 int dest_regno ATTRIBUTE_UNUSED
;
1068 regset live
= (regset
) data
;
1069 SET_REGNO_REG_SET (live
, src_regno
);
1073 /* Propagate global life info around the graph of basic blocks. Begin
1074 considering blocks with their corresponding bit set in BLOCKS_IN.
1075 If BLOCKS_IN is null, consider it the universal set.
1077 BLOCKS_OUT is set for every block that was changed. */
1080 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1081 sbitmap blocks_in
, blocks_out
;
1084 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1085 regset tmp
, new_live_at_end
, invalidated_by_call
;
1086 regset_head tmp_head
, invalidated_by_call_head
;
1087 regset_head new_live_at_end_head
;
1090 /* Some passes used to forget clear aux field of basic block causing
1091 sick behaviour here. */
1092 #ifdef ENABLE_CHECKING
1093 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1098 tmp
= INITIALIZE_REG_SET (tmp_head
);
1099 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1100 invalidated_by_call
= INITIALIZE_REG_SET (invalidated_by_call_head
);
1102 /* Inconveniently, this is only readily available in hard reg set form. */
1103 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1104 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1105 SET_REGNO_REG_SET (invalidated_by_call
, i
);
1107 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1108 because the `head == tail' style test for an empty queue doesn't
1109 work with a full queue. */
1110 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1112 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1114 /* Queue the blocks set in the initial mask. Do this in reverse block
1115 number order so that we are more likely for the first round to do
1116 useful work. We use AUX non-null to flag that the block is queued. */
1120 if (TEST_BIT (blocks_in
, bb
->index
))
1135 /* We clean aux when we remove the initially-enqueued bbs, but we
1136 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1138 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1141 sbitmap_zero (blocks_out
);
1143 /* We work through the queue until there are no more blocks. What
1144 is live at the end of this block is precisely the union of what
1145 is live at the beginning of all its successors. So, we set its
1146 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1147 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1148 this block by walking through the instructions in this block in
1149 reverse order and updating as we go. If that changed
1150 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1151 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1153 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1154 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1155 must either be live at the end of the block, or used within the
1156 block. In the latter case, it will certainly never disappear
1157 from GLOBAL_LIVE_AT_START. In the former case, the register
1158 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1159 for one of the successor blocks. By induction, that cannot
1161 while (qhead
!= qtail
)
1163 int rescan
, changed
;
1172 /* Begin by propagating live_at_start from the successor blocks. */
1173 CLEAR_REG_SET (new_live_at_end
);
1176 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1178 basic_block sb
= e
->dest
;
1180 /* Call-clobbered registers die across exception and
1182 /* ??? Abnormal call edges ignored for the moment, as this gets
1183 confused by sibling call edges, which crashes reg-stack. */
1184 if (e
->flags
& EDGE_EH
)
1186 bitmap_operation (tmp
, sb
->global_live_at_start
,
1187 invalidated_by_call
, BITMAP_AND_COMPL
);
1188 IOR_REG_SET (new_live_at_end
, tmp
);
1191 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1193 /* If a target saves one register in another (instead of on
1194 the stack) the save register will need to be live for EH. */
1195 if (e
->flags
& EDGE_EH
)
1196 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1198 SET_REGNO_REG_SET (new_live_at_end
, i
);
1202 /* This might be a noreturn function that throws. And
1203 even if it isn't, getting the unwind info right helps
1205 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1207 SET_REGNO_REG_SET (new_live_at_end
, i
);
1210 /* The all-important stack pointer must always be live. */
1211 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1213 /* Before reload, there are a few registers that must be forced
1214 live everywhere -- which might not already be the case for
1215 blocks within infinite loops. */
1216 if (! reload_completed
)
1218 /* Any reference to any pseudo before reload is a potential
1219 reference of the frame pointer. */
1220 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1222 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1223 /* Pseudos with argument area equivalences may require
1224 reloading via the argument pointer. */
1225 if (fixed_regs
[ARG_POINTER_REGNUM
])
1226 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1229 /* Any constant, or pseudo with constant equivalences, may
1230 require reloading from memory using the pic register. */
1231 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1232 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1233 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1236 /* Regs used in phi nodes are not included in
1237 global_live_at_start, since they are live only along a
1238 particular edge. Set those regs that are live because of a
1239 phi node alternative corresponding to this particular block. */
1241 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1244 if (bb
== ENTRY_BLOCK_PTR
)
1246 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1250 /* On our first pass through this block, we'll go ahead and continue.
1251 Recognize first pass by local_set NULL. On subsequent passes, we
1252 get to skip out early if live_at_end wouldn't have changed. */
1254 if (bb
->local_set
== NULL
)
1256 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1257 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1262 /* If any bits were removed from live_at_end, we'll have to
1263 rescan the block. This wouldn't be necessary if we had
1264 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1265 local_live is really dependent on live_at_end. */
1266 CLEAR_REG_SET (tmp
);
1267 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1268 new_live_at_end
, BITMAP_AND_COMPL
);
1272 /* If any of the registers in the new live_at_end set are
1273 conditionally set in this basic block, we must rescan.
1274 This is because conditional lifetimes at the end of the
1275 block do not just take the live_at_end set into account,
1276 but also the liveness at the start of each successor
1277 block. We can miss changes in those sets if we only
1278 compare the new live_at_end against the previous one. */
1279 CLEAR_REG_SET (tmp
);
1280 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1281 bb
->cond_local_set
, BITMAP_AND
);
1286 /* Find the set of changed bits. Take this opportunity
1287 to notice that this set is empty and early out. */
1288 CLEAR_REG_SET (tmp
);
1289 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1290 new_live_at_end
, BITMAP_XOR
);
1294 /* If any of the changed bits overlap with local_set,
1295 we'll have to rescan the block. Detect overlap by
1296 the AND with ~local_set turning off bits. */
1297 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1302 /* Let our caller know that BB changed enough to require its
1303 death notes updated. */
1305 SET_BIT (blocks_out
, bb
->index
);
1309 /* Add to live_at_start the set of all registers in
1310 new_live_at_end that aren't in the old live_at_end. */
1312 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1314 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1316 changed
= bitmap_operation (bb
->global_live_at_start
,
1317 bb
->global_live_at_start
,
1324 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1326 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1327 into live_at_start. */
1328 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1329 bb
->cond_local_set
, flags
);
1331 /* If live_at start didn't change, no need to go farther. */
1332 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1335 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1338 /* Queue all predecessors of BB so that we may re-examine
1339 their live_at_end. */
1340 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1342 basic_block pb
= e
->src
;
1343 if (pb
->aux
== NULL
)
1354 FREE_REG_SET (new_live_at_end
);
1355 FREE_REG_SET (invalidated_by_call
);
1359 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1361 basic_block bb
= BASIC_BLOCK (i
);
1362 FREE_REG_SET (bb
->local_set
);
1363 FREE_REG_SET (bb
->cond_local_set
);
1370 FREE_REG_SET (bb
->local_set
);
1371 FREE_REG_SET (bb
->cond_local_set
);
1379 /* This structure is used to pass parameters to an from the
1380 the function find_regno_partial(). It is used to pass in the
1381 register number we are looking, as well as to return any rtx
1385 unsigned regno_to_find
;
1387 } find_regno_partial_param
;
1390 /* Find the rtx for the reg numbers specified in 'data' if it is
1391 part of an expression which only uses part of the register. Return
1392 it in the structure passed in. */
1394 find_regno_partial (ptr
, data
)
1398 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1399 unsigned reg
= param
->regno_to_find
;
1400 param
->retval
= NULL_RTX
;
1402 if (*ptr
== NULL_RTX
)
1405 switch (GET_CODE (*ptr
))
1409 case STRICT_LOW_PART
:
1410 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1412 param
->retval
= XEXP (*ptr
, 0);
1418 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1419 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1421 param
->retval
= SUBREG_REG (*ptr
);
1433 /* Process all immediate successors of the entry block looking for pseudo
1434 registers which are live on entry. Find all of those whose first
1435 instance is a partial register reference of some kind, and initialize
1436 them to 0 after the entry block. This will prevent bit sets within
1437 registers whose value is unknown, and may contain some kind of sticky
1438 bits we don't want. */
1441 initialize_uninitialized_subregs ()
1445 int reg
, did_something
= 0;
1446 find_regno_partial_param param
;
1448 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1450 basic_block bb
= e
->dest
;
1451 regset map
= bb
->global_live_at_start
;
1452 EXECUTE_IF_SET_IN_REG_SET (map
,
1453 FIRST_PSEUDO_REGISTER
, reg
,
1455 int uid
= REGNO_FIRST_UID (reg
);
1458 /* Find an insn which mentions the register we are looking for.
1459 Its preferable to have an instance of the register's rtl since
1460 there may be various flags set which we need to duplicate.
1461 If we can't find it, its probably an automatic whose initial
1462 value doesn't matter, or hopefully something we don't care about. */
1463 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1467 /* Found the insn, now get the REG rtx, if we can. */
1468 param
.regno_to_find
= reg
;
1469 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1470 if (param
.retval
!= NULL_RTX
)
1472 insn
= gen_move_insn (param
.retval
,
1473 CONST0_RTX (GET_MODE (param
.retval
)));
1474 insert_insn_on_edge (insn
, e
);
1482 commit_edge_insertions ();
1483 return did_something
;
1487 /* Subroutines of life analysis. */
1489 /* Allocate the permanent data structures that represent the results
1490 of life analysis. Not static since used also for stupid life analysis. */
1493 allocate_bb_life_data ()
1497 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1499 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1500 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1503 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1507 allocate_reg_life_data ()
1511 max_regno
= max_reg_num ();
1513 /* Recalculate the register space, in case it has grown. Old style
1514 vector oriented regsets would set regset_{size,bytes} here also. */
1515 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1517 /* Reset all the data we'll collect in propagate_block and its
1519 for (i
= 0; i
< max_regno
; i
++)
1523 REG_N_DEATHS (i
) = 0;
1524 REG_N_CALLS_CROSSED (i
) = 0;
1525 REG_LIVE_LENGTH (i
) = 0;
1526 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1530 /* Delete dead instructions for propagate_block. */
1533 propagate_block_delete_insn (insn
)
1536 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1538 /* If the insn referred to a label, and that label was attached to
1539 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1540 pretty much mandatory to delete it, because the ADDR_VEC may be
1541 referencing labels that no longer exist.
1543 INSN may reference a deleted label, particularly when a jump
1544 table has been optimized into a direct jump. There's no
1545 real good way to fix up the reference to the deleted label
1546 when the label is deleted, so we just allow it here. */
1548 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1550 rtx label
= XEXP (inote
, 0);
1553 /* The label may be forced if it has been put in the constant
1554 pool. If that is the only use we must discard the table
1555 jump following it, but not the label itself. */
1556 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1557 && (next
= next_nonnote_insn (label
)) != NULL
1558 && GET_CODE (next
) == JUMP_INSN
1559 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1560 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1562 rtx pat
= PATTERN (next
);
1563 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1564 int len
= XVECLEN (pat
, diff_vec_p
);
1567 for (i
= 0; i
< len
; i
++)
1568 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1570 delete_insn_and_edges (next
);
1575 delete_insn_and_edges (insn
);
1579 /* Delete dead libcalls for propagate_block. Return the insn
1580 before the libcall. */
1583 propagate_block_delete_libcall ( insn
, note
)
1586 rtx first
= XEXP (note
, 0);
1587 rtx before
= PREV_INSN (first
);
1589 delete_insn_chain_and_edges (first
, insn
);
1594 /* Update the life-status of regs for one insn. Return the previous insn. */
1597 propagate_one_insn (pbi
, insn
)
1598 struct propagate_block_info
*pbi
;
1601 rtx prev
= PREV_INSN (insn
);
1602 int flags
= pbi
->flags
;
1603 int insn_is_dead
= 0;
1604 int libcall_is_dead
= 0;
1608 if (! INSN_P (insn
))
1611 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1612 if (flags
& PROP_SCAN_DEAD_CODE
)
1614 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1615 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1616 && libcall_dead_p (pbi
, note
, insn
));
1619 /* If an instruction consists of just dead store(s) on final pass,
1621 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1623 /* If we're trying to delete a prologue or epilogue instruction
1624 that isn't flagged as possibly being dead, something is wrong.
1625 But if we are keeping the stack pointer depressed, we might well
1626 be deleting insns that are used to compute the amount to update
1627 it by, so they are fine. */
1628 if (reload_completed
1629 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1630 && (TYPE_RETURNS_STACK_DEPRESSED
1631 (TREE_TYPE (current_function_decl
))))
1632 && (((HAVE_epilogue
|| HAVE_prologue
)
1633 && prologue_epilogue_contains (insn
))
1634 || (HAVE_sibcall_epilogue
1635 && sibcall_epilogue_contains (insn
)))
1636 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1637 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1639 /* Record sets. Do this even for dead instructions, since they
1640 would have killed the values if they hadn't been deleted. */
1641 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1643 /* CC0 is now known to be dead. Either this insn used it,
1644 in which case it doesn't anymore, or clobbered it,
1645 so the next insn can't use it. */
1648 if (libcall_is_dead
)
1649 prev
= propagate_block_delete_libcall ( insn
, note
);
1653 /* If INSN contains a RETVAL note and is dead, but the libcall
1654 as a whole is not dead, then we want to remove INSN, but
1655 not the whole libcall sequence.
1657 However, we need to also remove the dangling REG_LIBCALL
1658 note so that we do not have mis-matched LIBCALL/RETVAL
1659 notes. In theory we could find a new location for the
1660 REG_RETVAL note, but it hardly seems worth the effort.
1662 NOTE at this point will be the RETVAL note if it exists. */
1668 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1669 remove_note (XEXP (note
, 0), libcall_note
);
1672 /* Similarly if INSN contains a LIBCALL note, remove the
1673 dnagling REG_RETVAL note. */
1674 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
1680 = find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
1681 remove_note (XEXP (note
, 0), retval_note
);
1684 /* Now delete INSN. */
1685 propagate_block_delete_insn (insn
);
1691 /* See if this is an increment or decrement that can be merged into
1692 a following memory address. */
1695 rtx x
= single_set (insn
);
1697 /* Does this instruction increment or decrement a register? */
1698 if ((flags
& PROP_AUTOINC
)
1700 && GET_CODE (SET_DEST (x
)) == REG
1701 && (GET_CODE (SET_SRC (x
)) == PLUS
1702 || GET_CODE (SET_SRC (x
)) == MINUS
)
1703 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1704 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1705 /* Ok, look for a following memory ref we can combine with.
1706 If one is found, change the memory ref to a PRE_INC
1707 or PRE_DEC, cancel this insn, and return 1.
1708 Return 0 if nothing has been done. */
1709 && try_pre_increment_1 (pbi
, insn
))
1712 #endif /* AUTO_INC_DEC */
1714 CLEAR_REG_SET (pbi
->new_set
);
1716 /* If this is not the final pass, and this insn is copying the value of
1717 a library call and it's dead, don't scan the insns that perform the
1718 library call, so that the call's arguments are not marked live. */
1719 if (libcall_is_dead
)
1721 /* Record the death of the dest reg. */
1722 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1724 insn
= XEXP (note
, 0);
1725 return PREV_INSN (insn
);
1727 else if (GET_CODE (PATTERN (insn
)) == SET
1728 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1729 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1730 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1731 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1732 /* We have an insn to pop a constant amount off the stack.
1733 (Such insns use PLUS regardless of the direction of the stack,
1734 and any insn to adjust the stack by a constant is always a pop.)
1735 These insns, if not dead stores, have no effect on life, though
1736 they do have an effect on the memory stores we are tracking. */
1737 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1741 /* Any regs live at the time of a call instruction must not go
1742 in a register clobbered by calls. Find all regs now live and
1743 record this for them. */
1745 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1746 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1747 { REG_N_CALLS_CROSSED (i
)++; });
1749 /* Record sets. Do this even for dead instructions, since they
1750 would have killed the values if they hadn't been deleted. */
1751 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1753 if (GET_CODE (insn
) == CALL_INSN
)
1759 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1760 cond
= COND_EXEC_TEST (PATTERN (insn
));
1762 /* Non-constant calls clobber memory, constant calls do not
1763 clobber memory, though they may clobber outgoing arguments
1765 if (! CONST_OR_PURE_CALL_P (insn
))
1767 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1768 pbi
->mem_set_list_len
= 0;
1771 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1773 /* There may be extra registers to be clobbered. */
1774 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1776 note
= XEXP (note
, 1))
1777 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1778 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1779 cond
, insn
, pbi
->flags
);
1781 /* Calls change all call-used and global registers. */
1782 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1783 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1785 /* We do not want REG_UNUSED notes for these registers. */
1786 mark_set_1 (pbi
, CLOBBER
, regno_reg_rtx
[i
], cond
, insn
,
1787 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1791 /* If an insn doesn't use CC0, it becomes dead since we assume
1792 that every insn clobbers it. So show it dead here;
1793 mark_used_regs will set it live if it is referenced. */
1798 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1799 if ((flags
& PROP_EQUAL_NOTES
)
1800 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1801 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1802 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1804 /* Sometimes we may have inserted something before INSN (such as a move)
1805 when we make an auto-inc. So ensure we will scan those insns. */
1807 prev
= PREV_INSN (insn
);
1810 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1816 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1817 cond
= COND_EXEC_TEST (PATTERN (insn
));
1819 /* Calls use their arguments. */
1820 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1822 note
= XEXP (note
, 1))
1823 if (GET_CODE (XEXP (note
, 0)) == USE
)
1824 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1827 /* The stack ptr is used (honorarily) by a CALL insn. */
1828 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1830 /* Calls may also reference any of the global registers,
1831 so they are made live. */
1832 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1834 mark_used_reg (pbi
, regno_reg_rtx
[i
], cond
, insn
);
1838 /* On final pass, update counts of how many insns in which each reg
1840 if (flags
& PROP_REG_INFO
)
1841 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1842 { REG_LIVE_LENGTH (i
)++; });
1847 /* Initialize a propagate_block_info struct for public consumption.
1848 Note that the structure itself is opaque to this file, but that
1849 the user can use the regsets provided here. */
1851 struct propagate_block_info
*
1852 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1854 regset live
, local_set
, cond_local_set
;
1857 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1860 pbi
->reg_live
= live
;
1861 pbi
->mem_set_list
= NULL_RTX
;
1862 pbi
->mem_set_list_len
= 0;
1863 pbi
->local_set
= local_set
;
1864 pbi
->cond_local_set
= cond_local_set
;
1868 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1869 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1871 pbi
->reg_next_use
= NULL
;
1873 pbi
->new_set
= BITMAP_XMALLOC ();
1875 #ifdef HAVE_conditional_execution
1876 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1877 free_reg_cond_life_info
);
1878 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1880 /* If this block ends in a conditional branch, for each register live
1881 from one side of the branch and not the other, record the register
1882 as conditionally dead. */
1883 if (GET_CODE (bb
->end
) == JUMP_INSN
1884 && any_condjump_p (bb
->end
))
1886 regset_head diff_head
;
1887 regset diff
= INITIALIZE_REG_SET (diff_head
);
1888 basic_block bb_true
, bb_false
;
1889 rtx cond_true
, cond_false
, set_src
;
1892 /* Identify the successor blocks. */
1893 bb_true
= bb
->succ
->dest
;
1894 if (bb
->succ
->succ_next
!= NULL
)
1896 bb_false
= bb
->succ
->succ_next
->dest
;
1898 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1900 basic_block t
= bb_false
;
1904 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1909 /* This can happen with a conditional jump to the next insn. */
1910 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1913 /* Simplest way to do nothing. */
1917 /* Extract the condition from the branch. */
1918 set_src
= SET_SRC (pc_set (bb
->end
));
1919 cond_true
= XEXP (set_src
, 0);
1920 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1921 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1922 XEXP (cond_true
, 1));
1923 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1926 cond_false
= cond_true
;
1930 /* Compute which register lead different lives in the successors. */
1931 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1932 bb_false
->global_live_at_start
, BITMAP_XOR
))
1934 rtx reg
= XEXP (cond_true
, 0);
1936 if (GET_CODE (reg
) == SUBREG
)
1937 reg
= SUBREG_REG (reg
);
1939 if (GET_CODE (reg
) != REG
)
1942 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1944 /* For each such register, mark it conditionally dead. */
1945 EXECUTE_IF_SET_IN_REG_SET
1948 struct reg_cond_life_info
*rcli
;
1951 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1953 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1957 rcli
->condition
= cond
;
1958 rcli
->stores
= const0_rtx
;
1959 rcli
->orig_condition
= cond
;
1961 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1962 (splay_tree_value
) rcli
);
1966 FREE_REG_SET (diff
);
1970 /* If this block has no successors, any stores to the frame that aren't
1971 used later in the block are dead. So make a pass over the block
1972 recording any such that are made and show them dead at the end. We do
1973 a very conservative and simple job here. */
1975 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1976 && (TYPE_RETURNS_STACK_DEPRESSED
1977 (TREE_TYPE (current_function_decl
))))
1978 && (flags
& PROP_SCAN_DEAD_STORES
)
1979 && (bb
->succ
== NULL
1980 || (bb
->succ
->succ_next
== NULL
1981 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1982 && ! current_function_calls_eh_return
)))
1985 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1986 if (GET_CODE (insn
) == INSN
1987 && (set
= single_set (insn
))
1988 && GET_CODE (SET_DEST (set
)) == MEM
)
1990 rtx mem
= SET_DEST (set
);
1991 rtx canon_mem
= canon_rtx (mem
);
1993 /* This optimization is performed by faking a store to the
1994 memory at the end of the block. This doesn't work for
1995 unchanging memories because multiple stores to unchanging
1996 memory is illegal and alias analysis doesn't consider it. */
1997 if (RTX_UNCHANGING_P (canon_mem
))
2000 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
2001 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
2002 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
2003 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
2004 add_to_mem_set_list (pbi
, canon_mem
);
2011 /* Release a propagate_block_info struct. */
2014 free_propagate_block_info (pbi
)
2015 struct propagate_block_info
*pbi
;
2017 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2019 BITMAP_XFREE (pbi
->new_set
);
2021 #ifdef HAVE_conditional_execution
2022 splay_tree_delete (pbi
->reg_cond_dead
);
2023 BITMAP_XFREE (pbi
->reg_cond_reg
);
2026 if (pbi
->reg_next_use
)
2027 free (pbi
->reg_next_use
);
2032 /* Compute the registers live at the beginning of a basic block BB from
2033 those live at the end.
2035 When called, REG_LIVE contains those live at the end. On return, it
2036 contains those live at the beginning.
2038 LOCAL_SET, if non-null, will be set with all registers killed
2039 unconditionally by this basic block.
2040 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2041 killed conditionally by this basic block. If there is any unconditional
2042 set of a register, then the corresponding bit will be set in LOCAL_SET
2043 and cleared in COND_LOCAL_SET.
2044 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2045 case, the resulting set will be equal to the union of the two sets that
2046 would otherwise be computed.
2048 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2051 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2055 regset cond_local_set
;
2058 struct propagate_block_info
*pbi
;
2062 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2064 if (flags
& PROP_REG_INFO
)
2068 /* Process the regs live at the end of the block.
2069 Mark them as not local to any one basic block. */
2070 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2071 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2074 /* Scan the block an insn at a time from end to beginning. */
2077 for (insn
= bb
->end
;; insn
= prev
)
2079 /* If this is a call to `setjmp' et al, warn if any
2080 non-volatile datum is live. */
2081 if ((flags
& PROP_REG_INFO
)
2082 && GET_CODE (insn
) == CALL_INSN
2083 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2084 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2086 prev
= propagate_one_insn (pbi
, insn
);
2087 changed
|= NEXT_INSN (prev
) != insn
;
2089 if (insn
== bb
->head
)
2093 free_propagate_block_info (pbi
);
2098 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2099 (SET expressions whose destinations are registers dead after the insn).
2100 NEEDED is the regset that says which regs are alive after the insn.
2102 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2104 If X is the entire body of an insn, NOTES contains the reg notes
2105 pertaining to the insn. */
2108 insn_dead_p (pbi
, x
, call_ok
, notes
)
2109 struct propagate_block_info
*pbi
;
2112 rtx notes ATTRIBUTE_UNUSED
;
2114 enum rtx_code code
= GET_CODE (x
);
2117 /* As flow is invoked after combine, we must take existing AUTO_INC
2118 expressions into account. */
2119 for (; notes
; notes
= XEXP (notes
, 1))
2121 if (REG_NOTE_KIND (notes
) == REG_INC
)
2123 int regno
= REGNO (XEXP (notes
, 0));
2125 /* Don't delete insns to set global regs. */
2126 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2127 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2133 /* If setting something that's a reg or part of one,
2134 see if that register's altered value will be live. */
2138 rtx r
= SET_DEST (x
);
2141 if (GET_CODE (r
) == CC0
)
2142 return ! pbi
->cc0_live
;
2145 /* A SET that is a subroutine call cannot be dead. */
2146 if (GET_CODE (SET_SRC (x
)) == CALL
)
2152 /* Don't eliminate loads from volatile memory or volatile asms. */
2153 else if (volatile_refs_p (SET_SRC (x
)))
2156 if (GET_CODE (r
) == MEM
)
2160 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2163 canon_r
= canon_rtx (r
);
2165 /* Walk the set of memory locations we are currently tracking
2166 and see if one is an identical match to this memory location.
2167 If so, this memory write is dead (remember, we're walking
2168 backwards from the end of the block to the start). Since
2169 rtx_equal_p does not check the alias set or flags, we also
2170 must have the potential for them to conflict (anti_dependence). */
2171 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2172 if (anti_dependence (r
, XEXP (temp
, 0)))
2174 rtx mem
= XEXP (temp
, 0);
2176 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2177 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2178 <= GET_MODE_SIZE (GET_MODE (mem
))))
2182 /* Check if memory reference matches an auto increment. Only
2183 post increment/decrement or modify are valid. */
2184 if (GET_MODE (mem
) == GET_MODE (r
)
2185 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2186 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2187 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2188 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2189 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2196 while (GET_CODE (r
) == SUBREG
2197 || GET_CODE (r
) == STRICT_LOW_PART
2198 || GET_CODE (r
) == ZERO_EXTRACT
)
2201 if (GET_CODE (r
) == REG
)
2203 int regno
= REGNO (r
);
2206 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2209 /* If this is a hard register, verify that subsequent
2210 words are not needed. */
2211 if (regno
< FIRST_PSEUDO_REGISTER
)
2213 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2216 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2220 /* Don't delete insns to set global regs. */
2221 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2224 /* Make sure insns to set the stack pointer aren't deleted. */
2225 if (regno
== STACK_POINTER_REGNUM
)
2228 /* ??? These bits might be redundant with the force live bits
2229 in calculate_global_regs_live. We would delete from
2230 sequential sets; whether this actually affects real code
2231 for anything but the stack pointer I don't know. */
2232 /* Make sure insns to set the frame pointer aren't deleted. */
2233 if (regno
== FRAME_POINTER_REGNUM
2234 && (! reload_completed
|| frame_pointer_needed
))
2236 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2237 if (regno
== HARD_FRAME_POINTER_REGNUM
2238 && (! reload_completed
|| frame_pointer_needed
))
2242 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2243 /* Make sure insns to set arg pointer are never deleted
2244 (if the arg pointer isn't fixed, there will be a USE
2245 for it, so we can treat it normally). */
2246 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2250 /* Otherwise, the set is dead. */
2256 /* If performing several activities, insn is dead if each activity
2257 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2258 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2260 else if (code
== PARALLEL
)
2262 int i
= XVECLEN (x
, 0);
2264 for (i
--; i
>= 0; i
--)
2265 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2266 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2267 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2273 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2274 is not necessarily true for hard registers. */
2275 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2276 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2277 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2280 /* We do not check other CLOBBER or USE here. An insn consisting of just
2281 a CLOBBER or just a USE should not be deleted. */
2285 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2286 return 1 if the entire library call is dead.
2287 This is true if INSN copies a register (hard or pseudo)
2288 and if the hard return reg of the call insn is dead.
2289 (The caller should have tested the destination of the SET inside
2290 INSN already for death.)
2292 If this insn doesn't just copy a register, then we don't
2293 have an ordinary libcall. In that case, cse could not have
2294 managed to substitute the source for the dest later on,
2295 so we can assume the libcall is dead.
2297 PBI is the block info giving pseudoregs live before this insn.
2298 NOTE is the REG_RETVAL note of the insn. */
2301 libcall_dead_p (pbi
, note
, insn
)
2302 struct propagate_block_info
*pbi
;
2306 rtx x
= single_set (insn
);
2310 rtx r
= SET_SRC (x
);
2312 if (GET_CODE (r
) == REG
)
2314 rtx call
= XEXP (note
, 0);
2318 /* Find the call insn. */
2319 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2320 call
= NEXT_INSN (call
);
2322 /* If there is none, do nothing special,
2323 since ordinary death handling can understand these insns. */
2327 /* See if the hard reg holding the value is dead.
2328 If this is a PARALLEL, find the call within it. */
2329 call_pat
= PATTERN (call
);
2330 if (GET_CODE (call_pat
) == PARALLEL
)
2332 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2333 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2334 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2337 /* This may be a library call that is returning a value
2338 via invisible pointer. Do nothing special, since
2339 ordinary death handling can understand these insns. */
2343 call_pat
= XVECEXP (call_pat
, 0, i
);
2346 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2352 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2353 live at function entry. Don't count global register variables, variables
2354 in registers that can be used for function arg passing, or variables in
2355 fixed hard registers. */
2358 regno_uninitialized (regno
)
2361 if (n_basic_blocks
== 0
2362 || (regno
< FIRST_PSEUDO_REGISTER
2363 && (global_regs
[regno
]
2364 || fixed_regs
[regno
]
2365 || FUNCTION_ARG_REGNO_P (regno
))))
2368 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2371 /* 1 if register REGNO was alive at a place where `setjmp' was called
2372 and was set more than once or is an argument.
2373 Such regs may be clobbered by `longjmp'. */
2376 regno_clobbered_at_setjmp (regno
)
2379 if (n_basic_blocks
== 0)
2382 return ((REG_N_SETS (regno
) > 1
2383 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2384 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2387 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2388 maximal list size; look for overlaps in mode and select the largest. */
2390 add_to_mem_set_list (pbi
, mem
)
2391 struct propagate_block_info
*pbi
;
2396 /* We don't know how large a BLKmode store is, so we must not
2397 take them into consideration. */
2398 if (GET_MODE (mem
) == BLKmode
)
2401 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2403 rtx e
= XEXP (i
, 0);
2404 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2406 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2409 /* If we must store a copy of the mem, we can just modify
2410 the mode of the stored copy. */
2411 if (pbi
->flags
& PROP_AUTOINC
)
2412 PUT_MODE (e
, GET_MODE (mem
));
2421 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2424 /* Store a copy of mem, otherwise the address may be
2425 scrogged by find_auto_inc. */
2426 if (pbi
->flags
& PROP_AUTOINC
)
2427 mem
= shallow_copy_rtx (mem
);
2429 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2430 pbi
->mem_set_list_len
++;
2434 /* INSN references memory, possibly using autoincrement addressing modes.
2435 Find any entries on the mem_set_list that need to be invalidated due
2436 to an address change. */
2439 invalidate_mems_from_autoinc (px
, data
)
2444 struct propagate_block_info
*pbi
= data
;
2446 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2448 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2455 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2458 invalidate_mems_from_set (pbi
, exp
)
2459 struct propagate_block_info
*pbi
;
2462 rtx temp
= pbi
->mem_set_list
;
2463 rtx prev
= NULL_RTX
;
2468 next
= XEXP (temp
, 1);
2469 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2471 /* Splice this entry out of the list. */
2473 XEXP (prev
, 1) = next
;
2475 pbi
->mem_set_list
= next
;
2476 free_EXPR_LIST_node (temp
);
2477 pbi
->mem_set_list_len
--;
2485 /* Process the registers that are set within X. Their bits are set to
2486 1 in the regset DEAD, because they are dead prior to this insn.
2488 If INSN is nonzero, it is the insn being processed.
2490 FLAGS is the set of operations to perform. */
2493 mark_set_regs (pbi
, x
, insn
)
2494 struct propagate_block_info
*pbi
;
2497 rtx cond
= NULL_RTX
;
2502 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2504 if (REG_NOTE_KIND (link
) == REG_INC
)
2505 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2506 (GET_CODE (x
) == COND_EXEC
2507 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2511 switch (code
= GET_CODE (x
))
2515 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2519 cond
= COND_EXEC_TEST (x
);
2520 x
= COND_EXEC_CODE (x
);
2527 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2529 rtx sub
= XVECEXP (x
, 0, i
);
2530 switch (code
= GET_CODE (sub
))
2533 if (cond
!= NULL_RTX
)
2536 cond
= COND_EXEC_TEST (sub
);
2537 sub
= COND_EXEC_CODE (sub
);
2538 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2544 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2559 /* Process a single set, which appears in INSN. REG (which may not
2560 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2561 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2562 If the set is conditional (because it appear in a COND_EXEC), COND
2563 will be the condition. */
2566 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2567 struct propagate_block_info
*pbi
;
2569 rtx reg
, cond
, insn
;
2572 int regno_first
= -1, regno_last
= -1;
2573 unsigned long not_dead
= 0;
2576 /* Modifying just one hardware register of a multi-reg value or just a
2577 byte field of a register does not mean the value from before this insn
2578 is now dead. Of course, if it was dead after it's unused now. */
2580 switch (GET_CODE (reg
))
2583 /* Some targets place small structures in registers for return values of
2584 functions. We have to detect this case specially here to get correct
2585 flow information. */
2586 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2587 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2588 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2594 case STRICT_LOW_PART
:
2595 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2597 reg
= XEXP (reg
, 0);
2598 while (GET_CODE (reg
) == SUBREG
2599 || GET_CODE (reg
) == ZERO_EXTRACT
2600 || GET_CODE (reg
) == SIGN_EXTRACT
2601 || GET_CODE (reg
) == STRICT_LOW_PART
);
2602 if (GET_CODE (reg
) == MEM
)
2604 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2608 regno_last
= regno_first
= REGNO (reg
);
2609 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2610 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2614 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2616 enum machine_mode outer_mode
= GET_MODE (reg
);
2617 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2619 /* Identify the range of registers affected. This is moderately
2620 tricky for hard registers. See alter_subreg. */
2622 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2623 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2625 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2628 regno_last
= (regno_first
2629 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2631 /* Since we've just adjusted the register number ranges, make
2632 sure REG matches. Otherwise some_was_live will be clear
2633 when it shouldn't have been, and we'll create incorrect
2634 REG_UNUSED notes. */
2635 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2639 /* If the number of words in the subreg is less than the number
2640 of words in the full register, we have a well-defined partial
2641 set. Otherwise the high bits are undefined.
2643 This is only really applicable to pseudos, since we just took
2644 care of multi-word hard registers. */
2645 if (((GET_MODE_SIZE (outer_mode
)
2646 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2647 < ((GET_MODE_SIZE (inner_mode
)
2648 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2649 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2652 reg
= SUBREG_REG (reg
);
2656 reg
= SUBREG_REG (reg
);
2663 /* If this set is a MEM, then it kills any aliased writes.
2664 If this set is a REG, then it kills any MEMs which use the reg. */
2665 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2667 if (GET_CODE (reg
) == REG
)
2668 invalidate_mems_from_set (pbi
, reg
);
2670 /* If the memory reference had embedded side effects (autoincrement
2671 address modes. Then we may need to kill some entries on the
2673 if (insn
&& GET_CODE (reg
) == MEM
)
2674 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2676 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2677 /* ??? With more effort we could track conditional memory life. */
2679 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2682 if (GET_CODE (reg
) == REG
2683 && ! (regno_first
== FRAME_POINTER_REGNUM
2684 && (! reload_completed
|| frame_pointer_needed
))
2685 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2686 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2687 && (! reload_completed
|| frame_pointer_needed
))
2689 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2690 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2694 int some_was_live
= 0, some_was_dead
= 0;
2696 for (i
= regno_first
; i
<= regno_last
; ++i
)
2698 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2701 /* Order of the set operation matters here since both
2702 sets may be the same. */
2703 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2704 if (cond
!= NULL_RTX
2705 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2706 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2708 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2710 if (code
!= CLOBBER
)
2711 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2713 some_was_live
|= needed_regno
;
2714 some_was_dead
|= ! needed_regno
;
2717 #ifdef HAVE_conditional_execution
2718 /* Consider conditional death in deciding that the register needs
2720 if (some_was_live
&& ! not_dead
2721 /* The stack pointer is never dead. Well, not strictly true,
2722 but it's very difficult to tell from here. Hopefully
2723 combine_stack_adjustments will fix up the most egregious
2725 && regno_first
!= STACK_POINTER_REGNUM
)
2727 for (i
= regno_first
; i
<= regno_last
; ++i
)
2728 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2729 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2733 /* Additional data to record if this is the final pass. */
2734 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2735 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2738 int blocknum
= pbi
->bb
->index
;
2741 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2743 y
= pbi
->reg_next_use
[regno_first
];
2745 /* The next use is no longer next, since a store intervenes. */
2746 for (i
= regno_first
; i
<= regno_last
; ++i
)
2747 pbi
->reg_next_use
[i
] = 0;
2750 if (flags
& PROP_REG_INFO
)
2752 for (i
= regno_first
; i
<= regno_last
; ++i
)
2754 /* Count (weighted) references, stores, etc. This counts a
2755 register twice if it is modified, but that is correct. */
2756 REG_N_SETS (i
) += 1;
2757 REG_N_REFS (i
) += 1;
2758 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2760 /* The insns where a reg is live are normally counted
2761 elsewhere, but we want the count to include the insn
2762 where the reg is set, and the normal counting mechanism
2763 would not count it. */
2764 REG_LIVE_LENGTH (i
) += 1;
2767 /* If this is a hard reg, record this function uses the reg. */
2768 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2770 for (i
= regno_first
; i
<= regno_last
; i
++)
2771 regs_ever_live
[i
] = 1;
2775 /* Keep track of which basic blocks each reg appears in. */
2776 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2777 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2778 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2779 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2783 if (! some_was_dead
)
2785 if (flags
& PROP_LOG_LINKS
)
2787 /* Make a logical link from the next following insn
2788 that uses this register, back to this insn.
2789 The following insns have already been processed.
2791 We don't build a LOG_LINK for hard registers containing
2792 in ASM_OPERANDs. If these registers get replaced,
2793 we might wind up changing the semantics of the insn,
2794 even if reload can make what appear to be valid
2795 assignments later. */
2796 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2797 && (regno_first
>= FIRST_PSEUDO_REGISTER
2798 || asm_noperands (PATTERN (y
)) < 0))
2799 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2804 else if (! some_was_live
)
2806 if (flags
& PROP_REG_INFO
)
2807 REG_N_DEATHS (regno_first
) += 1;
2809 if (flags
& PROP_DEATH_NOTES
)
2811 /* Note that dead stores have already been deleted
2812 when possible. If we get here, we have found a
2813 dead store that cannot be eliminated (because the
2814 same insn does something useful). Indicate this
2815 by marking the reg being set as dying here. */
2817 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2822 if (flags
& PROP_DEATH_NOTES
)
2824 /* This is a case where we have a multi-word hard register
2825 and some, but not all, of the words of the register are
2826 needed in subsequent insns. Write REG_UNUSED notes
2827 for those parts that were not needed. This case should
2830 for (i
= regno_first
; i
<= regno_last
; ++i
)
2831 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2833 = alloc_EXPR_LIST (REG_UNUSED
,
2840 /* Mark the register as being dead. */
2842 /* The stack pointer is never dead. Well, not strictly true,
2843 but it's very difficult to tell from here. Hopefully
2844 combine_stack_adjustments will fix up the most egregious
2846 && regno_first
!= STACK_POINTER_REGNUM
)
2848 for (i
= regno_first
; i
<= regno_last
; ++i
)
2849 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2850 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2853 else if (GET_CODE (reg
) == REG
)
2855 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2856 pbi
->reg_next_use
[regno_first
] = 0;
2859 /* If this is the last pass and this is a SCRATCH, show it will be dying
2860 here and count it. */
2861 else if (GET_CODE (reg
) == SCRATCH
)
2863 if (flags
& PROP_DEATH_NOTES
)
2865 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2869 #ifdef HAVE_conditional_execution
2870 /* Mark REGNO conditionally dead.
2871 Return true if the register is now unconditionally dead. */
2874 mark_regno_cond_dead (pbi
, regno
, cond
)
2875 struct propagate_block_info
*pbi
;
2879 /* If this is a store to a predicate register, the value of the
2880 predicate is changing, we don't know that the predicate as seen
2881 before is the same as that seen after. Flush all dependent
2882 conditions from reg_cond_dead. This will make all such
2883 conditionally live registers unconditionally live. */
2884 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2885 flush_reg_cond_reg (pbi
, regno
);
2887 /* If this is an unconditional store, remove any conditional
2888 life that may have existed. */
2889 if (cond
== NULL_RTX
)
2890 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2893 splay_tree_node node
;
2894 struct reg_cond_life_info
*rcli
;
2897 /* Otherwise this is a conditional set. Record that fact.
2898 It may have been conditionally used, or there may be a
2899 subsequent set with a complimentary condition. */
2901 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2904 /* The register was unconditionally live previously.
2905 Record the current condition as the condition under
2906 which it is dead. */
2907 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2908 rcli
->condition
= cond
;
2909 rcli
->stores
= cond
;
2910 rcli
->orig_condition
= const0_rtx
;
2911 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2912 (splay_tree_value
) rcli
);
2914 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2916 /* Not unconditionally dead. */
2921 /* The register was conditionally live previously.
2922 Add the new condition to the old. */
2923 rcli
= (struct reg_cond_life_info
*) node
->value
;
2924 ncond
= rcli
->condition
;
2925 ncond
= ior_reg_cond (ncond
, cond
, 1);
2926 if (rcli
->stores
== const0_rtx
)
2927 rcli
->stores
= cond
;
2928 else if (rcli
->stores
!= const1_rtx
)
2929 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2931 /* If the register is now unconditionally dead, remove the entry
2932 in the splay_tree. A register is unconditionally dead if the
2933 dead condition ncond is true. A register is also unconditionally
2934 dead if the sum of all conditional stores is an unconditional
2935 store (stores is true), and the dead condition is identically the
2936 same as the original dead condition initialized at the end of
2937 the block. This is a pointer compare, not an rtx_equal_p
2939 if (ncond
== const1_rtx
2940 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2941 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2944 rcli
->condition
= ncond
;
2946 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2948 /* Not unconditionally dead. */
2957 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2960 free_reg_cond_life_info (value
)
2961 splay_tree_value value
;
2963 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2967 /* Helper function for flush_reg_cond_reg. */
2970 flush_reg_cond_reg_1 (node
, data
)
2971 splay_tree_node node
;
2974 struct reg_cond_life_info
*rcli
;
2975 int *xdata
= (int *) data
;
2976 unsigned int regno
= xdata
[0];
2978 /* Don't need to search if last flushed value was farther on in
2979 the in-order traversal. */
2980 if (xdata
[1] >= (int) node
->key
)
2983 /* Splice out portions of the expression that refer to regno. */
2984 rcli
= (struct reg_cond_life_info
*) node
->value
;
2985 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2986 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2987 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2989 /* If the entire condition is now false, signal the node to be removed. */
2990 if (rcli
->condition
== const0_rtx
)
2992 xdata
[1] = node
->key
;
2995 else if (rcli
->condition
== const1_rtx
)
3001 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3004 flush_reg_cond_reg (pbi
, regno
)
3005 struct propagate_block_info
*pbi
;
3012 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3013 flush_reg_cond_reg_1
, pair
) == -1)
3014 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3016 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3019 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3020 For ior/and, the ADD flag determines whether we want to add the new
3021 condition X to the old one unconditionally. If it is zero, we will
3022 only return a new expression if X allows us to simplify part of
3023 OLD, otherwise we return NULL to the caller.
3024 If ADD is nonzero, we will return a new condition in all cases. The
3025 toplevel caller of one of these functions should always pass 1 for
3029 ior_reg_cond (old
, x
, add
)
3035 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3037 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3038 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3039 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3041 if (GET_CODE (x
) == GET_CODE (old
)
3042 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3046 return gen_rtx_IOR (0, old
, x
);
3049 switch (GET_CODE (old
))
3052 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3053 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3054 if (op0
!= NULL
|| op1
!= NULL
)
3056 if (op0
== const0_rtx
)
3057 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3058 if (op1
== const0_rtx
)
3059 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3060 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3063 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3064 else if (rtx_equal_p (x
, op0
))
3065 /* (x | A) | x ~ (x | A). */
3068 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3069 else if (rtx_equal_p (x
, op1
))
3070 /* (A | x) | x ~ (A | x). */
3072 return gen_rtx_IOR (0, op0
, op1
);
3076 return gen_rtx_IOR (0, old
, x
);
3079 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3080 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3081 if (op0
!= NULL
|| op1
!= NULL
)
3083 if (op0
== const1_rtx
)
3084 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3085 if (op1
== const1_rtx
)
3086 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3087 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3090 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3091 else if (rtx_equal_p (x
, op0
))
3092 /* (x & A) | x ~ x. */
3095 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3096 else if (rtx_equal_p (x
, op1
))
3097 /* (A & x) | x ~ x. */
3099 return gen_rtx_AND (0, op0
, op1
);
3103 return gen_rtx_IOR (0, old
, x
);
3106 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3108 return not_reg_cond (op0
);
3111 return gen_rtx_IOR (0, old
, x
);
3122 enum rtx_code x_code
;
3124 if (x
== const0_rtx
)
3126 else if (x
== const1_rtx
)
3128 x_code
= GET_CODE (x
);
3131 if (GET_RTX_CLASS (x_code
) == '<'
3132 && GET_CODE (XEXP (x
, 0)) == REG
)
3134 if (XEXP (x
, 1) != const0_rtx
)
3137 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3138 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3140 return gen_rtx_NOT (0, x
);
3144 and_reg_cond (old
, x
, add
)
3150 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3152 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3153 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3154 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3156 if (GET_CODE (x
) == GET_CODE (old
)
3157 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3161 return gen_rtx_AND (0, old
, x
);
3164 switch (GET_CODE (old
))
3167 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3168 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3169 if (op0
!= NULL
|| op1
!= NULL
)
3171 if (op0
== const0_rtx
)
3172 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3173 if (op1
== const0_rtx
)
3174 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3175 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3178 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3179 else if (rtx_equal_p (x
, op0
))
3180 /* (x | A) & x ~ x. */
3183 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3184 else if (rtx_equal_p (x
, op1
))
3185 /* (A | x) & x ~ x. */
3187 return gen_rtx_IOR (0, op0
, op1
);
3191 return gen_rtx_AND (0, old
, x
);
3194 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3195 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3196 if (op0
!= NULL
|| op1
!= NULL
)
3198 if (op0
== const1_rtx
)
3199 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3200 if (op1
== const1_rtx
)
3201 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3202 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3205 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3206 else if (rtx_equal_p (x
, op0
))
3207 /* (x & A) & x ~ (x & A). */
3210 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3211 else if (rtx_equal_p (x
, op1
))
3212 /* (A & x) & x ~ (A & x). */
3214 return gen_rtx_AND (0, op0
, op1
);
3218 return gen_rtx_AND (0, old
, x
);
3221 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3223 return not_reg_cond (op0
);
3226 return gen_rtx_AND (0, old
, x
);
3233 /* Given a condition X, remove references to reg REGNO and return the
3234 new condition. The removal will be done so that all conditions
3235 involving REGNO are considered to evaluate to false. This function
3236 is used when the value of REGNO changes. */
3239 elim_reg_cond (x
, regno
)
3245 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3247 if (REGNO (XEXP (x
, 0)) == regno
)
3252 switch (GET_CODE (x
))
3255 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3256 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3257 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3259 if (op0
== const1_rtx
)
3261 if (op1
== const1_rtx
)
3263 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3265 return gen_rtx_AND (0, op0
, op1
);
3268 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3269 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3270 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3272 if (op0
== const0_rtx
)
3274 if (op1
== const0_rtx
)
3276 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3278 return gen_rtx_IOR (0, op0
, op1
);
3281 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3282 if (op0
== const0_rtx
)
3284 if (op0
== const1_rtx
)
3286 if (op0
!= XEXP (x
, 0))
3287 return not_reg_cond (op0
);
3294 #endif /* HAVE_conditional_execution */
3298 /* Try to substitute the auto-inc expression INC as the address inside
3299 MEM which occurs in INSN. Currently, the address of MEM is an expression
3300 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3301 that has a single set whose source is a PLUS of INCR_REG and something
3305 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3306 struct propagate_block_info
*pbi
;
3307 rtx inc
, insn
, mem
, incr
, incr_reg
;
3309 int regno
= REGNO (incr_reg
);
3310 rtx set
= single_set (incr
);
3311 rtx q
= SET_DEST (set
);
3312 rtx y
= SET_SRC (set
);
3313 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3315 /* Make sure this reg appears only once in this insn. */
3316 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3319 if (dead_or_set_p (incr
, incr_reg
)
3320 /* Mustn't autoinc an eliminable register. */
3321 && (regno
>= FIRST_PSEUDO_REGISTER
3322 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3324 /* This is the simple case. Try to make the auto-inc. If
3325 we can't, we are done. Otherwise, we will do any
3326 needed updates below. */
3327 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3330 else if (GET_CODE (q
) == REG
3331 /* PREV_INSN used here to check the semi-open interval
3333 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3334 /* We must also check for sets of q as q may be
3335 a call clobbered hard register and there may
3336 be a call between PREV_INSN (insn) and incr. */
3337 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3339 /* We have *p followed sometime later by q = p+size.
3340 Both p and q must be live afterward,
3341 and q is not used between INSN and its assignment.
3342 Change it to q = p, ...*q..., q = q+size.
3343 Then fall into the usual case. */
3347 emit_move_insn (q
, incr_reg
);
3348 insns
= get_insns ();
3351 /* If we can't make the auto-inc, or can't make the
3352 replacement into Y, exit. There's no point in making
3353 the change below if we can't do the auto-inc and doing
3354 so is not correct in the pre-inc case. */
3357 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3358 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3359 if (! apply_change_group ())
3362 /* We now know we'll be doing this change, so emit the
3363 new insn(s) and do the updates. */
3364 emit_insn_before (insns
, insn
);
3366 if (pbi
->bb
->head
== insn
)
3367 pbi
->bb
->head
= insns
;
3369 /* INCR will become a NOTE and INSN won't contain a
3370 use of INCR_REG. If a use of INCR_REG was just placed in
3371 the insn before INSN, make that the next use.
3372 Otherwise, invalidate it. */
3373 if (GET_CODE (PREV_INSN (insn
)) == INSN
3374 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3375 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3376 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3378 pbi
->reg_next_use
[regno
] = 0;
3383 /* REGNO is now used in INCR which is below INSN, but
3384 it previously wasn't live here. If we don't mark
3385 it as live, we'll put a REG_DEAD note for it
3386 on this insn, which is incorrect. */
3387 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3389 /* If there are any calls between INSN and INCR, show
3390 that REGNO now crosses them. */
3391 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3392 if (GET_CODE (temp
) == CALL_INSN
)
3393 REG_N_CALLS_CROSSED (regno
)++;
3395 /* Invalidate alias info for Q since we just changed its value. */
3396 clear_reg_alias_info (q
);
3401 /* If we haven't returned, it means we were able to make the
3402 auto-inc, so update the status. First, record that this insn
3403 has an implicit side effect. */
3405 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3407 /* Modify the old increment-insn to simply copy
3408 the already-incremented value of our register. */
3409 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3412 /* If that makes it a no-op (copying the register into itself) delete
3413 it so it won't appear to be a "use" and a "set" of this
3415 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3417 /* If the original source was dead, it's dead now. */
3420 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3422 remove_note (incr
, note
);
3423 if (XEXP (note
, 0) != incr_reg
)
3424 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3427 PUT_CODE (incr
, NOTE
);
3428 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3429 NOTE_SOURCE_FILE (incr
) = 0;
3432 if (regno
>= FIRST_PSEUDO_REGISTER
)
3434 /* Count an extra reference to the reg. When a reg is
3435 incremented, spilling it is worse, so we want to make
3436 that less likely. */
3437 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3439 /* Count the increment as a setting of the register,
3440 even though it isn't a SET in rtl. */
3441 REG_N_SETS (regno
)++;
3445 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3449 find_auto_inc (pbi
, x
, insn
)
3450 struct propagate_block_info
*pbi
;
3454 rtx addr
= XEXP (x
, 0);
3455 HOST_WIDE_INT offset
= 0;
3456 rtx set
, y
, incr
, inc_val
;
3458 int size
= GET_MODE_SIZE (GET_MODE (x
));
3460 if (GET_CODE (insn
) == JUMP_INSN
)
3463 /* Here we detect use of an index register which might be good for
3464 postincrement, postdecrement, preincrement, or predecrement. */
3466 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3467 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3469 if (GET_CODE (addr
) != REG
)
3472 regno
= REGNO (addr
);
3474 /* Is the next use an increment that might make auto-increment? */
3475 incr
= pbi
->reg_next_use
[regno
];
3476 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3478 set
= single_set (incr
);
3479 if (set
== 0 || GET_CODE (set
) != SET
)
3483 if (GET_CODE (y
) != PLUS
)
3486 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3487 inc_val
= XEXP (y
, 1);
3488 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3489 inc_val
= XEXP (y
, 0);
3493 if (GET_CODE (inc_val
) == CONST_INT
)
3495 if (HAVE_POST_INCREMENT
3496 && (INTVAL (inc_val
) == size
&& offset
== 0))
3497 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3499 else if (HAVE_POST_DECREMENT
3500 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3501 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3503 else if (HAVE_PRE_INCREMENT
3504 && (INTVAL (inc_val
) == size
&& offset
== size
))
3505 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3507 else if (HAVE_PRE_DECREMENT
3508 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3509 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3511 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3512 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3513 gen_rtx_PLUS (Pmode
,
3516 insn
, x
, incr
, addr
);
3518 else if (GET_CODE (inc_val
) == REG
3519 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3523 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3524 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3525 gen_rtx_PLUS (Pmode
,
3528 insn
, x
, incr
, addr
);
3532 #endif /* AUTO_INC_DEC */
3535 mark_used_reg (pbi
, reg
, cond
, insn
)
3536 struct propagate_block_info
*pbi
;
3538 rtx cond ATTRIBUTE_UNUSED
;
3541 unsigned int regno_first
, regno_last
, i
;
3542 int some_was_live
, some_was_dead
, some_not_set
;
3544 regno_last
= regno_first
= REGNO (reg
);
3545 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3546 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3548 /* Find out if any of this register is live after this instruction. */
3549 some_was_live
= some_was_dead
= 0;
3550 for (i
= regno_first
; i
<= regno_last
; ++i
)
3552 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3553 some_was_live
|= needed_regno
;
3554 some_was_dead
|= ! needed_regno
;
3557 /* Find out if any of the register was set this insn. */
3559 for (i
= regno_first
; i
<= regno_last
; ++i
)
3560 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3562 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3564 /* Record where each reg is used, so when the reg is set we know
3565 the next insn that uses it. */
3566 pbi
->reg_next_use
[regno_first
] = insn
;
3569 if (pbi
->flags
& PROP_REG_INFO
)
3571 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3573 /* If this is a register we are going to try to eliminate,
3574 don't mark it live here. If we are successful in
3575 eliminating it, it need not be live unless it is used for
3576 pseudos, in which case it will have been set live when it
3577 was allocated to the pseudos. If the register will not
3578 be eliminated, reload will set it live at that point.
3580 Otherwise, record that this function uses this register. */
3581 /* ??? The PPC backend tries to "eliminate" on the pic
3582 register to itself. This should be fixed. In the mean
3583 time, hack around it. */
3585 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3586 && (regno_first
== FRAME_POINTER_REGNUM
3587 || regno_first
== ARG_POINTER_REGNUM
)))
3588 for (i
= regno_first
; i
<= regno_last
; ++i
)
3589 regs_ever_live
[i
] = 1;
3593 /* Keep track of which basic block each reg appears in. */
3595 int blocknum
= pbi
->bb
->index
;
3596 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3597 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3598 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3599 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3601 /* Count (weighted) number of uses of each reg. */
3602 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3603 REG_N_REFS (regno_first
)++;
3607 /* Record and count the insns in which a reg dies. If it is used in
3608 this insn and was dead below the insn then it dies in this insn.
3609 If it was set in this insn, we do not make a REG_DEAD note;
3610 likewise if we already made such a note. */
3611 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3615 /* Check for the case where the register dying partially
3616 overlaps the register set by this insn. */
3617 if (regno_first
!= regno_last
)
3618 for (i
= regno_first
; i
<= regno_last
; ++i
)
3619 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3621 /* If none of the words in X is needed, make a REG_DEAD note.
3622 Otherwise, we must make partial REG_DEAD notes. */
3623 if (! some_was_live
)
3625 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3626 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3628 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3630 if (pbi
->flags
& PROP_REG_INFO
)
3631 REG_N_DEATHS (regno_first
)++;
3635 /* Don't make a REG_DEAD note for a part of a register
3636 that is set in the insn. */
3637 for (i
= regno_first
; i
<= regno_last
; ++i
)
3638 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3639 && ! dead_or_set_regno_p (insn
, i
))
3641 = alloc_EXPR_LIST (REG_DEAD
,
3647 /* Mark the register as being live. */
3648 for (i
= regno_first
; i
<= regno_last
; ++i
)
3650 #ifdef HAVE_conditional_execution
3651 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3654 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3656 #ifdef HAVE_conditional_execution
3657 /* If this is a conditional use, record that fact. If it is later
3658 conditionally set, we'll know to kill the register. */
3659 if (cond
!= NULL_RTX
)
3661 splay_tree_node node
;
3662 struct reg_cond_life_info
*rcli
;
3667 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3670 /* The register was unconditionally live previously.
3671 No need to do anything. */
3675 /* The register was conditionally live previously.
3676 Subtract the new life cond from the old death cond. */
3677 rcli
= (struct reg_cond_life_info
*) node
->value
;
3678 ncond
= rcli
->condition
;
3679 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3681 /* If the register is now unconditionally live,
3682 remove the entry in the splay_tree. */
3683 if (ncond
== const0_rtx
)
3684 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3687 rcli
->condition
= ncond
;
3688 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3689 REGNO (XEXP (cond
, 0)));
3695 /* The register was not previously live at all. Record
3696 the condition under which it is still dead. */
3697 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3698 rcli
->condition
= not_reg_cond (cond
);
3699 rcli
->stores
= const0_rtx
;
3700 rcli
->orig_condition
= const0_rtx
;
3701 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3702 (splay_tree_value
) rcli
);
3704 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3707 else if (this_was_live
)
3709 /* The register may have been conditionally live previously, but
3710 is now unconditionally live. Remove it from the conditionally
3711 dead list, so that a conditional set won't cause us to think
3713 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3719 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3720 This is done assuming the registers needed from X are those that
3721 have 1-bits in PBI->REG_LIVE.
3723 INSN is the containing instruction. If INSN is dead, this function
3727 mark_used_regs (pbi
, x
, cond
, insn
)
3728 struct propagate_block_info
*pbi
;
3733 int flags
= pbi
->flags
;
3738 code
= GET_CODE (x
);
3759 /* If we are clobbering a MEM, mark any registers inside the address
3761 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3762 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3766 /* Don't bother watching stores to mems if this is not the
3767 final pass. We'll not be deleting dead stores this round. */
3768 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3770 /* Invalidate the data for the last MEM stored, but only if MEM is
3771 something that can be stored into. */
3772 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3773 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3774 /* Needn't clear the memory set list. */
3778 rtx temp
= pbi
->mem_set_list
;
3779 rtx prev
= NULL_RTX
;
3784 next
= XEXP (temp
, 1);
3785 if (anti_dependence (XEXP (temp
, 0), x
))
3787 /* Splice temp out of the list. */
3789 XEXP (prev
, 1) = next
;
3791 pbi
->mem_set_list
= next
;
3792 free_EXPR_LIST_node (temp
);
3793 pbi
->mem_set_list_len
--;
3801 /* If the memory reference had embedded side effects (autoincrement
3802 address modes. Then we may need to kill some entries on the
3805 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3809 if (flags
& PROP_AUTOINC
)
3810 find_auto_inc (pbi
, x
, insn
);
3815 #ifdef CLASS_CANNOT_CHANGE_MODE
3816 if (GET_CODE (SUBREG_REG (x
)) == REG
3817 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3818 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3819 GET_MODE (SUBREG_REG (x
))))
3820 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3823 /* While we're here, optimize this case. */
3825 if (GET_CODE (x
) != REG
)
3830 /* See a register other than being set => mark it as needed. */
3831 mark_used_reg (pbi
, x
, cond
, insn
);
3836 rtx testreg
= SET_DEST (x
);
3839 /* If storing into MEM, don't show it as being used. But do
3840 show the address as being used. */
3841 if (GET_CODE (testreg
) == MEM
)
3844 if (flags
& PROP_AUTOINC
)
3845 find_auto_inc (pbi
, testreg
, insn
);
3847 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3848 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3852 /* Storing in STRICT_LOW_PART is like storing in a reg
3853 in that this SET might be dead, so ignore it in TESTREG.
3854 but in some other ways it is like using the reg.
3856 Storing in a SUBREG or a bit field is like storing the entire
3857 register in that if the register's value is not used
3858 then this SET is not needed. */
3859 while (GET_CODE (testreg
) == STRICT_LOW_PART
3860 || GET_CODE (testreg
) == ZERO_EXTRACT
3861 || GET_CODE (testreg
) == SIGN_EXTRACT
3862 || GET_CODE (testreg
) == SUBREG
)
3864 #ifdef CLASS_CANNOT_CHANGE_MODE
3865 if (GET_CODE (testreg
) == SUBREG
3866 && GET_CODE (SUBREG_REG (testreg
)) == REG
3867 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3868 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3869 GET_MODE (testreg
)))
3870 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3873 /* Modifying a single register in an alternate mode
3874 does not use any of the old value. But these other
3875 ways of storing in a register do use the old value. */
3876 if (GET_CODE (testreg
) == SUBREG
3877 && !((REG_BYTES (SUBREG_REG (testreg
))
3878 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3879 > (REG_BYTES (testreg
)
3880 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3885 testreg
= XEXP (testreg
, 0);
3888 /* If this is a store into a register or group of registers,
3889 recursively scan the value being stored. */
3891 if ((GET_CODE (testreg
) == PARALLEL
3892 && GET_MODE (testreg
) == BLKmode
)
3893 || (GET_CODE (testreg
) == REG
3894 && (regno
= REGNO (testreg
),
3895 ! (regno
== FRAME_POINTER_REGNUM
3896 && (! reload_completed
|| frame_pointer_needed
)))
3897 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3898 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3899 && (! reload_completed
|| frame_pointer_needed
))
3901 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3902 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3907 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3908 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3915 case UNSPEC_VOLATILE
:
3919 /* Traditional and volatile asm instructions must be considered to use
3920 and clobber all hard registers, all pseudo-registers and all of
3921 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3923 Consider for instance a volatile asm that changes the fpu rounding
3924 mode. An insn should not be moved across this even if it only uses
3925 pseudo-regs because it might give an incorrectly rounded result.
3927 ?!? Unfortunately, marking all hard registers as live causes massive
3928 problems for the register allocator and marking all pseudos as live
3929 creates mountains of uninitialized variable warnings.
3931 So for now, just clear the memory set list and mark any regs
3932 we can find in ASM_OPERANDS as used. */
3933 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3935 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3936 pbi
->mem_set_list_len
= 0;
3939 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3940 We can not just fall through here since then we would be confused
3941 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3942 traditional asms unlike their normal usage. */
3943 if (code
== ASM_OPERANDS
)
3947 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3948 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3954 if (cond
!= NULL_RTX
)
3957 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3959 cond
= COND_EXEC_TEST (x
);
3960 x
= COND_EXEC_CODE (x
);
3964 /* We _do_not_ want to scan operands of phi nodes. Operands of
3965 a phi function are evaluated only when control reaches this
3966 block along a particular edge. Therefore, regs that appear
3967 as arguments to phi should not be added to the global live at
3975 /* Recursively scan the operands of this expression. */
3978 const char * const fmt
= GET_RTX_FORMAT (code
);
3981 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3985 /* Tail recursive case: save a function call level. */
3991 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3993 else if (fmt
[i
] == 'E')
3996 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3997 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4006 try_pre_increment_1 (pbi
, insn
)
4007 struct propagate_block_info
*pbi
;
4010 /* Find the next use of this reg. If in same basic block,
4011 make it do pre-increment or pre-decrement if appropriate. */
4012 rtx x
= single_set (insn
);
4013 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4014 * INTVAL (XEXP (SET_SRC (x
), 1)));
4015 int regno
= REGNO (SET_DEST (x
));
4016 rtx y
= pbi
->reg_next_use
[regno
];
4018 && SET_DEST (x
) != stack_pointer_rtx
4019 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4020 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4021 mode would be better. */
4022 && ! dead_or_set_p (y
, SET_DEST (x
))
4023 && try_pre_increment (y
, SET_DEST (x
), amount
))
4025 /* We have found a suitable auto-increment and already changed
4026 insn Y to do it. So flush this increment instruction. */
4027 propagate_block_delete_insn (insn
);
4029 /* Count a reference to this reg for the increment insn we are
4030 deleting. When a reg is incremented, spilling it is worse,
4031 so we want to make that less likely. */
4032 if (regno
>= FIRST_PSEUDO_REGISTER
)
4034 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4035 REG_N_SETS (regno
)++;
4038 /* Flush any remembered memories depending on the value of
4039 the incremented register. */
4040 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4047 /* Try to change INSN so that it does pre-increment or pre-decrement
4048 addressing on register REG in order to add AMOUNT to REG.
4049 AMOUNT is negative for pre-decrement.
4050 Returns 1 if the change could be made.
4051 This checks all about the validity of the result of modifying INSN. */
4054 try_pre_increment (insn
, reg
, amount
)
4056 HOST_WIDE_INT amount
;
4060 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4061 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4063 /* Nonzero if we can try to make a post-increment or post-decrement.
4064 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4065 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4066 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4069 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4072 /* From the sign of increment, see which possibilities are conceivable
4073 on this target machine. */
4074 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4076 if (HAVE_POST_INCREMENT
&& amount
> 0)
4079 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4081 if (HAVE_POST_DECREMENT
&& amount
< 0)
4084 if (! (pre_ok
|| post_ok
))
4087 /* It is not safe to add a side effect to a jump insn
4088 because if the incremented register is spilled and must be reloaded
4089 there would be no way to store the incremented value back in memory. */
4091 if (GET_CODE (insn
) == JUMP_INSN
)
4096 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4097 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4099 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4103 if (use
== 0 || use
== (rtx
) (size_t) 1)
4106 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4109 /* See if this combination of instruction and addressing mode exists. */
4110 if (! validate_change (insn
, &XEXP (use
, 0),
4111 gen_rtx_fmt_e (amount
> 0
4112 ? (do_post
? POST_INC
: PRE_INC
)
4113 : (do_post
? POST_DEC
: PRE_DEC
),
4117 /* Record that this insn now has an implicit side effect on X. */
4118 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4122 #endif /* AUTO_INC_DEC */
4124 /* Find the place in the rtx X where REG is used as a memory address.
4125 Return the MEM rtx that so uses it.
4126 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4127 (plus REG (const_int PLUSCONST)).
4129 If such an address does not appear, return 0.
4130 If REG appears more than once, or is used other than in such an address,
4134 find_use_as_address (x
, reg
, plusconst
)
4137 HOST_WIDE_INT plusconst
;
4139 enum rtx_code code
= GET_CODE (x
);
4140 const char * const fmt
= GET_RTX_FORMAT (code
);
4145 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4148 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4149 && XEXP (XEXP (x
, 0), 0) == reg
4150 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4151 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4154 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4156 /* If REG occurs inside a MEM used in a bit-field reference,
4157 that is unacceptable. */
4158 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4159 return (rtx
) (size_t) 1;
4163 return (rtx
) (size_t) 1;
4165 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4169 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4173 return (rtx
) (size_t) 1;
4175 else if (fmt
[i
] == 'E')
4178 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4180 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4184 return (rtx
) (size_t) 1;
4192 /* Write information about registers and basic blocks into FILE.
4193 This is part of making a debugging dump. */
4196 dump_regset (r
, outf
)
4203 fputs (" (nil)", outf
);
4207 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4209 fprintf (outf
, " %d", i
);
4210 if (i
< FIRST_PSEUDO_REGISTER
)
4211 fprintf (outf
, " [%s]",
4216 /* Print a human-reaable representation of R on the standard error
4217 stream. This function is designed to be used from within the
4224 dump_regset (r
, stderr
);
4225 putc ('\n', stderr
);
4228 /* Recompute register set/reference counts immediately prior to register
4231 This avoids problems with set/reference counts changing to/from values
4232 which have special meanings to the register allocators.
4234 Additionally, the reference counts are the primary component used by the
4235 register allocators to prioritize pseudos for allocation to hard regs.
4236 More accurate reference counts generally lead to better register allocation.
4238 F is the first insn to be scanned.
4240 LOOP_STEP denotes how much loop_depth should be incremented per
4241 loop nesting level in order to increase the ref count more for
4242 references in a loop.
4244 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4245 possibly other information which is used by the register allocators. */
4248 recompute_reg_usage (f
, loop_step
)
4249 rtx f ATTRIBUTE_UNUSED
;
4250 int loop_step ATTRIBUTE_UNUSED
;
4252 allocate_reg_life_data ();
4253 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4256 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4257 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4258 of the number of registers that died. */
4261 count_or_remove_death_notes (blocks
, kill
)
4268 FOR_EACH_BB_REVERSE (bb
)
4272 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4275 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4279 rtx
*pprev
= ®_NOTES (insn
);
4284 switch (REG_NOTE_KIND (link
))
4287 if (GET_CODE (XEXP (link
, 0)) == REG
)
4289 rtx reg
= XEXP (link
, 0);
4292 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4295 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4303 rtx next
= XEXP (link
, 1);
4304 free_EXPR_LIST_node (link
);
4305 *pprev
= link
= next
;
4311 pprev
= &XEXP (link
, 1);
4318 if (insn
== bb
->end
)
4325 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4326 if blocks is NULL. */
4329 clear_log_links (blocks
)
4337 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4339 free_INSN_LIST_list (&LOG_LINKS (insn
));
4342 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4344 basic_block bb
= BASIC_BLOCK (i
);
4346 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4347 insn
= NEXT_INSN (insn
))
4349 free_INSN_LIST_list (&LOG_LINKS (insn
));
4353 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4354 correspond to the hard registers, if any, set in that map. This
4355 could be done far more efficiently by having all sorts of special-cases
4356 with moving single words, but probably isn't worth the trouble. */
4359 reg_set_to_hard_reg_set (to
, from
)
4365 EXECUTE_IF_SET_IN_BITMAP
4368 if (i
>= FIRST_PSEUDO_REGISTER
)
4370 SET_HARD_REG_BIT (*to
, i
);