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
)
376 /* Recompute insn->block mapping, since the initial mapping is
377 set before we delete unreachable blocks. */
378 if (BLOCK_FOR_INSN (cfun
->x_clobber_return_insn
) != NULL
)
379 warning ("control reaches end of non-void function");
384 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
385 note associated with the BLOCK. */
388 first_insn_after_basic_block_note (block
)
393 /* Get the first instruction in the block. */
396 if (insn
== NULL_RTX
)
398 if (GET_CODE (insn
) == CODE_LABEL
)
399 insn
= NEXT_INSN (insn
);
400 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
403 return NEXT_INSN (insn
);
406 /* Perform data flow analysis.
407 F is the first insn of the function; FLAGS is a set of PROP_* flags
408 to be used in accumulating flow info. */
411 life_analysis (f
, file
, flags
)
416 #ifdef ELIMINABLE_REGS
418 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
421 /* Record which registers will be eliminated. We use this in
424 CLEAR_HARD_REG_SET (elim_reg_set
);
426 #ifdef ELIMINABLE_REGS
427 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
428 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
430 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
434 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
436 /* The post-reload life analysis have (on a global basis) the same
437 registers live as was computed by reload itself. elimination
438 Otherwise offsets and such may be incorrect.
440 Reload will make some registers as live even though they do not
443 We don't want to create new auto-incs after reload, since they
444 are unlikely to be useful and can cause problems with shared
446 if (reload_completed
)
447 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
449 /* We want alias analysis information for local dead store elimination. */
450 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
451 init_alias_analysis ();
453 /* Always remove no-op moves. Do this before other processing so
454 that we don't have to keep re-scanning them. */
455 delete_noop_moves (f
);
457 /* Some targets can emit simpler epilogues if they know that sp was
458 not ever modified during the function. After reload, of course,
459 we've already emitted the epilogue so there's no sense searching. */
460 if (! reload_completed
)
461 notice_stack_pointer_modification (f
);
463 /* Allocate and zero out data structures that will record the
464 data from lifetime analysis. */
465 allocate_reg_life_data ();
466 allocate_bb_life_data ();
468 /* Find the set of registers live on function exit. */
469 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
471 /* "Update" life info from zero. It'd be nice to begin the
472 relaxation with just the exit and noreturn blocks, but that set
473 is not immediately handy. */
475 if (flags
& PROP_REG_INFO
)
476 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
477 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
480 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
481 end_alias_analysis ();
484 dump_flow_info (file
);
486 free_basic_block_vars (1);
488 /* Removing dead insns should've made jumptables really dead. */
489 delete_dead_jumptables ();
492 /* A subroutine of verify_wide_reg, called through for_each_rtx.
493 Search for REGNO. If found, return 2 if it is not wider than
497 verify_wide_reg_1 (px
, pregno
)
502 unsigned int regno
= *(int *) pregno
;
504 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
506 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
513 /* A subroutine of verify_local_live_at_start. Search through insns
514 of BB looking for register REGNO. */
517 verify_wide_reg (regno
, bb
)
521 rtx head
= bb
->head
, end
= bb
->end
;
527 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
535 head
= NEXT_INSN (head
);
540 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
541 dump_bb (bb
, rtl_dump_file
);
546 /* A subroutine of update_life_info. Verify that there are no untoward
547 changes in live_at_start during a local update. */
550 verify_local_live_at_start (new_live_at_start
, bb
)
551 regset new_live_at_start
;
554 if (reload_completed
)
556 /* After reload, there are no pseudos, nor subregs of multi-word
557 registers. The regsets should exactly match. */
558 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
562 fprintf (rtl_dump_file
,
563 "live_at_start mismatch in bb %d, aborting\nNew:\n",
565 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
566 fputs ("Old:\n", rtl_dump_file
);
567 dump_bb (bb
, rtl_dump_file
);
576 /* Find the set of changed registers. */
577 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
579 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
581 /* No registers should die. */
582 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
586 fprintf (rtl_dump_file
,
587 "Register %d died unexpectedly.\n", i
);
588 dump_bb (bb
, rtl_dump_file
);
593 /* Verify that the now-live register is wider than word_mode. */
594 verify_wide_reg (i
, bb
);
599 /* Updates life information starting with the basic blocks set in BLOCKS.
600 If BLOCKS is null, consider it to be the universal set.
602 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
603 we are only expecting local modifications to basic blocks. If we find
604 extra registers live at the beginning of a block, then we either killed
605 useful data, or we have a broken split that wants data not provided.
606 If we find registers removed from live_at_start, that means we have
607 a broken peephole that is killing a register it shouldn't.
609 ??? This is not true in one situation -- when a pre-reload splitter
610 generates subregs of a multi-word pseudo, current life analysis will
611 lose the kill. So we _can_ have a pseudo go live. How irritating.
613 Including PROP_REG_INFO does not properly refresh regs_ever_live
614 unless the caller resets it to zero. */
617 update_life_info (blocks
, extent
, prop_flags
)
619 enum update_life_extent extent
;
623 regset_head tmp_head
;
625 int stabilized_prop_flags
= prop_flags
;
628 tmp
= INITIALIZE_REG_SET (tmp_head
);
631 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
632 ? TV_LIFE_UPDATE
: TV_LIFE
);
634 /* Changes to the CFG are only allowed when
635 doing a global update for the entire CFG. */
636 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
637 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
640 /* For a global update, we go through the relaxation process again. */
641 if (extent
!= UPDATE_LIFE_LOCAL
)
647 calculate_global_regs_live (blocks
, blocks
,
648 prop_flags
& (PROP_SCAN_DEAD_CODE
649 | PROP_SCAN_DEAD_STORES
650 | PROP_ALLOW_CFG_CHANGES
));
652 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
653 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
656 /* Removing dead code may allow the CFG to be simplified which
657 in turn may allow for further dead code detection / removal. */
658 FOR_EACH_BB_REVERSE (bb
)
660 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
661 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
662 prop_flags
& (PROP_SCAN_DEAD_CODE
663 | PROP_SCAN_DEAD_STORES
664 | PROP_KILL_DEAD_CODE
));
667 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
668 subsequent propagate_block calls, since removing or acting as
669 removing dead code can affect global register liveness, which
670 is supposed to be finalized for this call after this loop. */
671 stabilized_prop_flags
672 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
673 | PROP_KILL_DEAD_CODE
);
678 /* We repeat regardless of what cleanup_cfg says. If there were
679 instructions deleted above, that might have been only a
680 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
681 Further improvement may be possible. */
682 cleanup_cfg (CLEANUP_EXPENSIVE
);
685 /* If asked, remove notes from the blocks we'll update. */
686 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
687 count_or_remove_death_notes (blocks
, 1);
690 /* Clear log links in case we are asked to (re)compute them. */
691 if (prop_flags
& PROP_LOG_LINKS
)
692 clear_log_links (blocks
);
696 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
698 bb
= BASIC_BLOCK (i
);
700 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
701 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
703 if (extent
== UPDATE_LIFE_LOCAL
)
704 verify_local_live_at_start (tmp
, bb
);
709 FOR_EACH_BB_REVERSE (bb
)
711 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
713 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
715 if (extent
== UPDATE_LIFE_LOCAL
)
716 verify_local_live_at_start (tmp
, bb
);
722 if (prop_flags
& PROP_REG_INFO
)
724 /* The only pseudos that are live at the beginning of the function
725 are those that were not set anywhere in the function. local-alloc
726 doesn't know how to handle these correctly, so mark them as not
727 local to any one basic block. */
728 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
729 FIRST_PSEUDO_REGISTER
, i
,
730 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
732 /* We have a problem with any pseudoreg that lives across the setjmp.
733 ANSI says that if a user variable does not change in value between
734 the setjmp and the longjmp, then the longjmp preserves it. This
735 includes longjmp from a place where the pseudo appears dead.
736 (In principle, the value still exists if it is in scope.)
737 If the pseudo goes in a hard reg, some other value may occupy
738 that hard reg where this pseudo is dead, thus clobbering the pseudo.
739 Conclusion: such a pseudo must not go in a hard reg. */
740 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
741 FIRST_PSEUDO_REGISTER
, i
,
743 if (regno_reg_rtx
[i
] != 0)
745 REG_LIVE_LENGTH (i
) = -1;
746 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
750 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
751 ? TV_LIFE_UPDATE
: TV_LIFE
);
752 if (ndead
&& rtl_dump_file
)
753 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
757 /* Update life information in all blocks where BB_DIRTY is set. */
760 update_life_info_in_dirty_blocks (extent
, prop_flags
)
761 enum update_life_extent extent
;
764 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
769 sbitmap_zero (update_life_blocks
);
772 if (extent
== UPDATE_LIFE_LOCAL
)
774 if (bb
->flags
& BB_DIRTY
)
776 SET_BIT (update_life_blocks
, bb
->index
);
782 /* ??? Bootstrap with -march=pentium4 fails to terminate
783 with only a partial life update. */
784 SET_BIT (update_life_blocks
, bb
->index
);
785 if (bb
->flags
& BB_DIRTY
)
791 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
793 sbitmap_free (update_life_blocks
);
797 /* Free the variables allocated by find_basic_blocks.
799 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
802 free_basic_block_vars (keep_head_end_p
)
805 if (! keep_head_end_p
)
807 if (basic_block_info
)
810 VARRAY_FREE (basic_block_info
);
813 last_basic_block
= 0;
815 ENTRY_BLOCK_PTR
->aux
= NULL
;
816 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
817 EXIT_BLOCK_PTR
->aux
= NULL
;
818 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
822 /* Delete any insns that copy a register to itself. */
825 delete_noop_moves (f
)
826 rtx f ATTRIBUTE_UNUSED
;
834 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
836 next
= NEXT_INSN (insn
);
837 if (INSN_P (insn
) && noop_move_p (insn
))
841 /* If we're about to remove the first insn of a libcall
842 then move the libcall note to the next real insn and
843 update the retval note. */
844 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
845 && XEXP (note
, 0) != insn
)
847 rtx new_libcall_insn
= next_real_insn (insn
);
848 rtx retval_note
= find_reg_note (XEXP (note
, 0),
849 REG_RETVAL
, NULL_RTX
);
850 REG_NOTES (new_libcall_insn
)
851 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
852 REG_NOTES (new_libcall_insn
));
853 XEXP (retval_note
, 0) = new_libcall_insn
;
856 delete_insn_and_edges (insn
);
861 if (nnoops
&& rtl_dump_file
)
862 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
866 /* Delete any jump tables never referenced. We can't delete them at the
867 time of removing tablejump insn as they are referenced by the preceding
868 insns computing the destination, so we delay deleting and garbagecollect
869 them once life information is computed. */
871 delete_dead_jumptables ()
874 for (insn
= get_insns (); insn
; insn
= next
)
876 next
= NEXT_INSN (insn
);
877 if (GET_CODE (insn
) == CODE_LABEL
878 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
879 && GET_CODE (next
) == JUMP_INSN
880 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
881 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
884 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
885 delete_insn (NEXT_INSN (insn
));
887 next
= NEXT_INSN (next
);
892 /* Determine if the stack pointer is constant over the life of the function.
893 Only useful before prologues have been emitted. */
896 notice_stack_pointer_modification_1 (x
, pat
, data
)
898 rtx pat ATTRIBUTE_UNUSED
;
899 void *data ATTRIBUTE_UNUSED
;
901 if (x
== stack_pointer_rtx
902 /* The stack pointer is only modified indirectly as the result
903 of a push until later in flow. See the comments in rtl.texi
904 regarding Embedded Side-Effects on Addresses. */
905 || (GET_CODE (x
) == MEM
906 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
907 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
908 current_function_sp_is_unchanging
= 0;
912 notice_stack_pointer_modification (f
)
917 /* Assume that the stack pointer is unchanging if alloca hasn't
919 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
920 if (! current_function_sp_is_unchanging
)
923 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
927 /* Check if insn modifies the stack pointer. */
928 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
930 if (! current_function_sp_is_unchanging
)
936 /* Mark a register in SET. Hard registers in large modes get all
937 of their component registers set as well. */
944 regset set
= (regset
) xset
;
945 int regno
= REGNO (reg
);
947 if (GET_MODE (reg
) == BLKmode
)
950 SET_REGNO_REG_SET (set
, regno
);
951 if (regno
< FIRST_PSEUDO_REGISTER
)
953 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
955 SET_REGNO_REG_SET (set
, regno
+ n
);
959 /* Mark those regs which are needed at the end of the function as live
960 at the end of the last basic block. */
963 mark_regs_live_at_end (set
)
968 /* If exiting needs the right stack value, consider the stack pointer
969 live at the end of the function. */
970 if ((HAVE_epilogue
&& reload_completed
)
971 || ! EXIT_IGNORE_STACK
972 || (! FRAME_POINTER_REQUIRED
973 && ! current_function_calls_alloca
974 && flag_omit_frame_pointer
)
975 || current_function_sp_is_unchanging
)
977 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
980 /* Mark the frame pointer if needed at the end of the function. If
981 we end up eliminating it, it will be removed from the live list
982 of each basic block by reload. */
984 if (! reload_completed
|| frame_pointer_needed
)
986 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
987 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
988 /* If they are different, also mark the hard frame pointer as live. */
989 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
990 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
994 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
995 /* Many architectures have a GP register even without flag_pic.
996 Assume the pic register is not in use, or will be handled by
997 other means, if it is not fixed. */
998 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
999 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1000 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1003 /* Mark all global registers, and all registers used by the epilogue
1004 as being live at the end of the function since they may be
1005 referenced by our caller. */
1006 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1007 if (global_regs
[i
] || EPILOGUE_USES (i
))
1008 SET_REGNO_REG_SET (set
, i
);
1010 if (HAVE_epilogue
&& reload_completed
)
1012 /* Mark all call-saved registers that we actually used. */
1013 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1014 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1015 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1016 SET_REGNO_REG_SET (set
, i
);
1019 #ifdef EH_RETURN_DATA_REGNO
1020 /* Mark the registers that will contain data for the handler. */
1021 if (reload_completed
&& current_function_calls_eh_return
)
1024 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1025 if (regno
== INVALID_REGNUM
)
1027 SET_REGNO_REG_SET (set
, regno
);
1030 #ifdef EH_RETURN_STACKADJ_RTX
1031 if ((! HAVE_epilogue
|| ! reload_completed
)
1032 && current_function_calls_eh_return
)
1034 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1035 if (tmp
&& REG_P (tmp
))
1036 mark_reg (tmp
, set
);
1039 #ifdef EH_RETURN_HANDLER_RTX
1040 if ((! HAVE_epilogue
|| ! reload_completed
)
1041 && current_function_calls_eh_return
)
1043 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1044 if (tmp
&& REG_P (tmp
))
1045 mark_reg (tmp
, set
);
1049 /* Mark function return value. */
1050 diddle_return_value (mark_reg
, set
);
1053 /* Callback function for for_each_successor_phi. DATA is a regset.
1054 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1055 INSN, in the regset. */
1058 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1059 rtx insn ATTRIBUTE_UNUSED
;
1060 int dest_regno ATTRIBUTE_UNUSED
;
1064 regset live
= (regset
) data
;
1065 SET_REGNO_REG_SET (live
, src_regno
);
1069 /* Propagate global life info around the graph of basic blocks. Begin
1070 considering blocks with their corresponding bit set in BLOCKS_IN.
1071 If BLOCKS_IN is null, consider it the universal set.
1073 BLOCKS_OUT is set for every block that was changed. */
1076 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1077 sbitmap blocks_in
, blocks_out
;
1080 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1081 regset tmp
, new_live_at_end
, invalidated_by_call
;
1082 regset_head tmp_head
, invalidated_by_call_head
;
1083 regset_head new_live_at_end_head
;
1086 /* Some passes used to forget clear aux field of basic block causing
1087 sick behaviour here. */
1088 #ifdef ENABLE_CHECKING
1089 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1094 tmp
= INITIALIZE_REG_SET (tmp_head
);
1095 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1096 invalidated_by_call
= INITIALIZE_REG_SET (invalidated_by_call_head
);
1098 /* Inconveniently, this is only readily available in hard reg set form. */
1099 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1100 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1101 SET_REGNO_REG_SET (invalidated_by_call
, i
);
1103 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1104 because the `head == tail' style test for an empty queue doesn't
1105 work with a full queue. */
1106 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1108 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1110 /* Queue the blocks set in the initial mask. Do this in reverse block
1111 number order so that we are more likely for the first round to do
1112 useful work. We use AUX non-null to flag that the block is queued. */
1116 if (TEST_BIT (blocks_in
, bb
->index
))
1131 /* We clean aux when we remove the initially-enqueued bbs, but we
1132 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1134 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1137 sbitmap_zero (blocks_out
);
1139 /* We work through the queue until there are no more blocks. What
1140 is live at the end of this block is precisely the union of what
1141 is live at the beginning of all its successors. So, we set its
1142 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1143 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1144 this block by walking through the instructions in this block in
1145 reverse order and updating as we go. If that changed
1146 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1147 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1149 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1150 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1151 must either be live at the end of the block, or used within the
1152 block. In the latter case, it will certainly never disappear
1153 from GLOBAL_LIVE_AT_START. In the former case, the register
1154 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1155 for one of the successor blocks. By induction, that cannot
1157 while (qhead
!= qtail
)
1159 int rescan
, changed
;
1168 /* Begin by propagating live_at_start from the successor blocks. */
1169 CLEAR_REG_SET (new_live_at_end
);
1172 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1174 basic_block sb
= e
->dest
;
1176 /* Call-clobbered registers die across exception and
1178 /* ??? Abnormal call edges ignored for the moment, as this gets
1179 confused by sibling call edges, which crashes reg-stack. */
1180 if (e
->flags
& EDGE_EH
)
1182 bitmap_operation (tmp
, sb
->global_live_at_start
,
1183 invalidated_by_call
, BITMAP_AND_COMPL
);
1184 IOR_REG_SET (new_live_at_end
, tmp
);
1187 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1189 /* If a target saves one register in another (instead of on
1190 the stack) the save register will need to be live for EH. */
1191 if (e
->flags
& EDGE_EH
)
1192 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1194 SET_REGNO_REG_SET (new_live_at_end
, i
);
1198 /* This might be a noreturn function that throws. And
1199 even if it isn't, getting the unwind info right helps
1201 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1203 SET_REGNO_REG_SET (new_live_at_end
, i
);
1206 /* The all-important stack pointer must always be live. */
1207 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1209 /* Before reload, there are a few registers that must be forced
1210 live everywhere -- which might not already be the case for
1211 blocks within infinite loops. */
1212 if (! reload_completed
)
1214 /* Any reference to any pseudo before reload is a potential
1215 reference of the frame pointer. */
1216 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1218 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1219 /* Pseudos with argument area equivalences may require
1220 reloading via the argument pointer. */
1221 if (fixed_regs
[ARG_POINTER_REGNUM
])
1222 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1225 /* Any constant, or pseudo with constant equivalences, may
1226 require reloading from memory using the pic register. */
1227 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1228 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1229 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1232 /* Regs used in phi nodes are not included in
1233 global_live_at_start, since they are live only along a
1234 particular edge. Set those regs that are live because of a
1235 phi node alternative corresponding to this particular block. */
1237 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1240 if (bb
== ENTRY_BLOCK_PTR
)
1242 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1246 /* On our first pass through this block, we'll go ahead and continue.
1247 Recognize first pass by local_set NULL. On subsequent passes, we
1248 get to skip out early if live_at_end wouldn't have changed. */
1250 if (bb
->local_set
== NULL
)
1252 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1253 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1258 /* If any bits were removed from live_at_end, we'll have to
1259 rescan the block. This wouldn't be necessary if we had
1260 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1261 local_live is really dependent on live_at_end. */
1262 CLEAR_REG_SET (tmp
);
1263 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1264 new_live_at_end
, BITMAP_AND_COMPL
);
1268 /* If any of the registers in the new live_at_end set are
1269 conditionally set in this basic block, we must rescan.
1270 This is because conditional lifetimes at the end of the
1271 block do not just take the live_at_end set into account,
1272 but also the liveness at the start of each successor
1273 block. We can miss changes in those sets if we only
1274 compare the new live_at_end against the previous one. */
1275 CLEAR_REG_SET (tmp
);
1276 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1277 bb
->cond_local_set
, BITMAP_AND
);
1282 /* Find the set of changed bits. Take this opportunity
1283 to notice that this set is empty and early out. */
1284 CLEAR_REG_SET (tmp
);
1285 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1286 new_live_at_end
, BITMAP_XOR
);
1290 /* If any of the changed bits overlap with local_set,
1291 we'll have to rescan the block. Detect overlap by
1292 the AND with ~local_set turning off bits. */
1293 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1298 /* Let our caller know that BB changed enough to require its
1299 death notes updated. */
1301 SET_BIT (blocks_out
, bb
->index
);
1305 /* Add to live_at_start the set of all registers in
1306 new_live_at_end that aren't in the old live_at_end. */
1308 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1310 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1312 changed
= bitmap_operation (bb
->global_live_at_start
,
1313 bb
->global_live_at_start
,
1320 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1322 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1323 into live_at_start. */
1324 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1325 bb
->cond_local_set
, flags
);
1327 /* If live_at start didn't change, no need to go farther. */
1328 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1331 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1334 /* Queue all predecessors of BB so that we may re-examine
1335 their live_at_end. */
1336 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1338 basic_block pb
= e
->src
;
1339 if (pb
->aux
== NULL
)
1350 FREE_REG_SET (new_live_at_end
);
1351 FREE_REG_SET (invalidated_by_call
);
1355 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1357 basic_block bb
= BASIC_BLOCK (i
);
1358 FREE_REG_SET (bb
->local_set
);
1359 FREE_REG_SET (bb
->cond_local_set
);
1366 FREE_REG_SET (bb
->local_set
);
1367 FREE_REG_SET (bb
->cond_local_set
);
1375 /* This structure is used to pass parameters to an from the
1376 the function find_regno_partial(). It is used to pass in the
1377 register number we are looking, as well as to return any rtx
1381 unsigned regno_to_find
;
1383 } find_regno_partial_param
;
1386 /* Find the rtx for the reg numbers specified in 'data' if it is
1387 part of an expression which only uses part of the register. Return
1388 it in the structure passed in. */
1390 find_regno_partial (ptr
, data
)
1394 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1395 unsigned reg
= param
->regno_to_find
;
1396 param
->retval
= NULL_RTX
;
1398 if (*ptr
== NULL_RTX
)
1401 switch (GET_CODE (*ptr
))
1405 case STRICT_LOW_PART
:
1406 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1408 param
->retval
= XEXP (*ptr
, 0);
1414 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1415 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1417 param
->retval
= SUBREG_REG (*ptr
);
1429 /* Process all immediate successors of the entry block looking for pseudo
1430 registers which are live on entry. Find all of those whose first
1431 instance is a partial register reference of some kind, and initialize
1432 them to 0 after the entry block. This will prevent bit sets within
1433 registers whose value is unknown, and may contain some kind of sticky
1434 bits we don't want. */
1437 initialize_uninitialized_subregs ()
1441 int reg
, did_something
= 0;
1442 find_regno_partial_param param
;
1444 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1446 basic_block bb
= e
->dest
;
1447 regset map
= bb
->global_live_at_start
;
1448 EXECUTE_IF_SET_IN_REG_SET (map
,
1449 FIRST_PSEUDO_REGISTER
, reg
,
1451 int uid
= REGNO_FIRST_UID (reg
);
1454 /* Find an insn which mentions the register we are looking for.
1455 Its preferable to have an instance of the register's rtl since
1456 there may be various flags set which we need to duplicate.
1457 If we can't find it, its probably an automatic whose initial
1458 value doesn't matter, or hopefully something we don't care about. */
1459 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1463 /* Found the insn, now get the REG rtx, if we can. */
1464 param
.regno_to_find
= reg
;
1465 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1466 if (param
.retval
!= NULL_RTX
)
1468 insn
= gen_move_insn (param
.retval
,
1469 CONST0_RTX (GET_MODE (param
.retval
)));
1470 insert_insn_on_edge (insn
, e
);
1478 commit_edge_insertions ();
1479 return did_something
;
1483 /* Subroutines of life analysis. */
1485 /* Allocate the permanent data structures that represent the results
1486 of life analysis. Not static since used also for stupid life analysis. */
1489 allocate_bb_life_data ()
1493 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1495 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1496 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1499 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1503 allocate_reg_life_data ()
1507 max_regno
= max_reg_num ();
1509 /* Recalculate the register space, in case it has grown. Old style
1510 vector oriented regsets would set regset_{size,bytes} here also. */
1511 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1513 /* Reset all the data we'll collect in propagate_block and its
1515 for (i
= 0; i
< max_regno
; i
++)
1519 REG_N_DEATHS (i
) = 0;
1520 REG_N_CALLS_CROSSED (i
) = 0;
1521 REG_LIVE_LENGTH (i
) = 0;
1522 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1526 /* Delete dead instructions for propagate_block. */
1529 propagate_block_delete_insn (insn
)
1532 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1534 /* If the insn referred to a label, and that label was attached to
1535 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1536 pretty much mandatory to delete it, because the ADDR_VEC may be
1537 referencing labels that no longer exist.
1539 INSN may reference a deleted label, particularly when a jump
1540 table has been optimized into a direct jump. There's no
1541 real good way to fix up the reference to the deleted label
1542 when the label is deleted, so we just allow it here. */
1544 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1546 rtx label
= XEXP (inote
, 0);
1549 /* The label may be forced if it has been put in the constant
1550 pool. If that is the only use we must discard the table
1551 jump following it, but not the label itself. */
1552 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1553 && (next
= next_nonnote_insn (label
)) != NULL
1554 && GET_CODE (next
) == JUMP_INSN
1555 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1556 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1558 rtx pat
= PATTERN (next
);
1559 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1560 int len
= XVECLEN (pat
, diff_vec_p
);
1563 for (i
= 0; i
< len
; i
++)
1564 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1566 delete_insn_and_edges (next
);
1571 delete_insn_and_edges (insn
);
1575 /* Delete dead libcalls for propagate_block. Return the insn
1576 before the libcall. */
1579 propagate_block_delete_libcall ( insn
, note
)
1582 rtx first
= XEXP (note
, 0);
1583 rtx before
= PREV_INSN (first
);
1585 delete_insn_chain_and_edges (first
, insn
);
1590 /* Update the life-status of regs for one insn. Return the previous insn. */
1593 propagate_one_insn (pbi
, insn
)
1594 struct propagate_block_info
*pbi
;
1597 rtx prev
= PREV_INSN (insn
);
1598 int flags
= pbi
->flags
;
1599 int insn_is_dead
= 0;
1600 int libcall_is_dead
= 0;
1604 if (! INSN_P (insn
))
1607 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1608 if (flags
& PROP_SCAN_DEAD_CODE
)
1610 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1611 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1612 && libcall_dead_p (pbi
, note
, insn
));
1615 /* If an instruction consists of just dead store(s) on final pass,
1617 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1619 /* If we're trying to delete a prologue or epilogue instruction
1620 that isn't flagged as possibly being dead, something is wrong.
1621 But if we are keeping the stack pointer depressed, we might well
1622 be deleting insns that are used to compute the amount to update
1623 it by, so they are fine. */
1624 if (reload_completed
1625 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1626 && (TYPE_RETURNS_STACK_DEPRESSED
1627 (TREE_TYPE (current_function_decl
))))
1628 && (((HAVE_epilogue
|| HAVE_prologue
)
1629 && prologue_epilogue_contains (insn
))
1630 || (HAVE_sibcall_epilogue
1631 && sibcall_epilogue_contains (insn
)))
1632 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1633 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1635 /* Record sets. Do this even for dead instructions, since they
1636 would have killed the values if they hadn't been deleted. */
1637 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1639 /* CC0 is now known to be dead. Either this insn used it,
1640 in which case it doesn't anymore, or clobbered it,
1641 so the next insn can't use it. */
1644 if (libcall_is_dead
)
1645 prev
= propagate_block_delete_libcall ( insn
, note
);
1651 /* If INSN contains a RETVAL note and is dead, but the libcall
1652 as a whole is not dead, then we want to remove INSN, but
1653 not the whole libcall sequence.
1655 However, we need to also remove the dangling REG_LIBCALL
1656 note so that we do not have mis-matched LIBCALL/RETVAL
1657 notes. In theory we could find a new location for the
1658 REG_RETVAL note, but it hardly seems worth the effort. */
1662 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1663 remove_note (XEXP (note
, 0), libcall_note
);
1665 propagate_block_delete_insn (insn
);
1671 /* See if this is an increment or decrement that can be merged into
1672 a following memory address. */
1675 rtx x
= single_set (insn
);
1677 /* Does this instruction increment or decrement a register? */
1678 if ((flags
& PROP_AUTOINC
)
1680 && GET_CODE (SET_DEST (x
)) == REG
1681 && (GET_CODE (SET_SRC (x
)) == PLUS
1682 || GET_CODE (SET_SRC (x
)) == MINUS
)
1683 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1684 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1685 /* Ok, look for a following memory ref we can combine with.
1686 If one is found, change the memory ref to a PRE_INC
1687 or PRE_DEC, cancel this insn, and return 1.
1688 Return 0 if nothing has been done. */
1689 && try_pre_increment_1 (pbi
, insn
))
1692 #endif /* AUTO_INC_DEC */
1694 CLEAR_REG_SET (pbi
->new_set
);
1696 /* If this is not the final pass, and this insn is copying the value of
1697 a library call and it's dead, don't scan the insns that perform the
1698 library call, so that the call's arguments are not marked live. */
1699 if (libcall_is_dead
)
1701 /* Record the death of the dest reg. */
1702 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1704 insn
= XEXP (note
, 0);
1705 return PREV_INSN (insn
);
1707 else if (GET_CODE (PATTERN (insn
)) == SET
1708 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1709 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1710 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1711 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1712 /* We have an insn to pop a constant amount off the stack.
1713 (Such insns use PLUS regardless of the direction of the stack,
1714 and any insn to adjust the stack by a constant is always a pop.)
1715 These insns, if not dead stores, have no effect on life, though
1716 they do have an effect on the memory stores we are tracking. */
1717 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1721 /* Any regs live at the time of a call instruction must not go
1722 in a register clobbered by calls. Find all regs now live and
1723 record this for them. */
1725 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1726 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1727 { REG_N_CALLS_CROSSED (i
)++; });
1729 /* Record sets. Do this even for dead instructions, since they
1730 would have killed the values if they hadn't been deleted. */
1731 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1733 if (GET_CODE (insn
) == CALL_INSN
)
1739 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1740 cond
= COND_EXEC_TEST (PATTERN (insn
));
1742 /* Non-constant calls clobber memory, constant calls do not
1743 clobber memory, though they may clobber outgoing arguments
1745 if (! CONST_OR_PURE_CALL_P (insn
))
1747 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1748 pbi
->mem_set_list_len
= 0;
1751 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1753 /* There may be extra registers to be clobbered. */
1754 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1756 note
= XEXP (note
, 1))
1757 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1758 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1759 cond
, insn
, pbi
->flags
);
1761 /* Calls change all call-used and global registers. */
1762 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1763 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1765 /* We do not want REG_UNUSED notes for these registers. */
1766 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1768 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1772 /* If an insn doesn't use CC0, it becomes dead since we assume
1773 that every insn clobbers it. So show it dead here;
1774 mark_used_regs will set it live if it is referenced. */
1779 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1780 if ((flags
& PROP_EQUAL_NOTES
)
1781 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1782 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1783 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1785 /* Sometimes we may have inserted something before INSN (such as a move)
1786 when we make an auto-inc. So ensure we will scan those insns. */
1788 prev
= PREV_INSN (insn
);
1791 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1797 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1798 cond
= COND_EXEC_TEST (PATTERN (insn
));
1800 /* Calls use their arguments. */
1801 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1803 note
= XEXP (note
, 1))
1804 if (GET_CODE (XEXP (note
, 0)) == USE
)
1805 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1808 /* The stack ptr is used (honorarily) by a CALL insn. */
1809 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1811 /* Calls may also reference any of the global registers,
1812 so they are made live. */
1813 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1815 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1820 /* On final pass, update counts of how many insns in which each reg
1822 if (flags
& PROP_REG_INFO
)
1823 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1824 { REG_LIVE_LENGTH (i
)++; });
1829 /* Initialize a propagate_block_info struct for public consumption.
1830 Note that the structure itself is opaque to this file, but that
1831 the user can use the regsets provided here. */
1833 struct propagate_block_info
*
1834 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1836 regset live
, local_set
, cond_local_set
;
1839 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1842 pbi
->reg_live
= live
;
1843 pbi
->mem_set_list
= NULL_RTX
;
1844 pbi
->mem_set_list_len
= 0;
1845 pbi
->local_set
= local_set
;
1846 pbi
->cond_local_set
= cond_local_set
;
1850 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1851 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1853 pbi
->reg_next_use
= NULL
;
1855 pbi
->new_set
= BITMAP_XMALLOC ();
1857 #ifdef HAVE_conditional_execution
1858 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1859 free_reg_cond_life_info
);
1860 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1862 /* If this block ends in a conditional branch, for each register live
1863 from one side of the branch and not the other, record the register
1864 as conditionally dead. */
1865 if (GET_CODE (bb
->end
) == JUMP_INSN
1866 && any_condjump_p (bb
->end
))
1868 regset_head diff_head
;
1869 regset diff
= INITIALIZE_REG_SET (diff_head
);
1870 basic_block bb_true
, bb_false
;
1871 rtx cond_true
, cond_false
, set_src
;
1874 /* Identify the successor blocks. */
1875 bb_true
= bb
->succ
->dest
;
1876 if (bb
->succ
->succ_next
!= NULL
)
1878 bb_false
= bb
->succ
->succ_next
->dest
;
1880 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1882 basic_block t
= bb_false
;
1886 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1891 /* This can happen with a conditional jump to the next insn. */
1892 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1895 /* Simplest way to do nothing. */
1899 /* Extract the condition from the branch. */
1900 set_src
= SET_SRC (pc_set (bb
->end
));
1901 cond_true
= XEXP (set_src
, 0);
1902 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1903 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1904 XEXP (cond_true
, 1));
1905 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1908 cond_false
= cond_true
;
1912 /* Compute which register lead different lives in the successors. */
1913 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1914 bb_false
->global_live_at_start
, BITMAP_XOR
))
1916 rtx reg
= XEXP (cond_true
, 0);
1918 if (GET_CODE (reg
) == SUBREG
)
1919 reg
= SUBREG_REG (reg
);
1921 if (GET_CODE (reg
) != REG
)
1924 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1926 /* For each such register, mark it conditionally dead. */
1927 EXECUTE_IF_SET_IN_REG_SET
1930 struct reg_cond_life_info
*rcli
;
1933 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1935 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1939 rcli
->condition
= cond
;
1940 rcli
->stores
= const0_rtx
;
1941 rcli
->orig_condition
= cond
;
1943 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1944 (splay_tree_value
) rcli
);
1948 FREE_REG_SET (diff
);
1952 /* If this block has no successors, any stores to the frame that aren't
1953 used later in the block are dead. So make a pass over the block
1954 recording any such that are made and show them dead at the end. We do
1955 a very conservative and simple job here. */
1957 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1958 && (TYPE_RETURNS_STACK_DEPRESSED
1959 (TREE_TYPE (current_function_decl
))))
1960 && (flags
& PROP_SCAN_DEAD_STORES
)
1961 && (bb
->succ
== NULL
1962 || (bb
->succ
->succ_next
== NULL
1963 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1964 && ! current_function_calls_eh_return
)))
1967 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1968 if (GET_CODE (insn
) == INSN
1969 && (set
= single_set (insn
))
1970 && GET_CODE (SET_DEST (set
)) == MEM
)
1972 rtx mem
= SET_DEST (set
);
1973 rtx canon_mem
= canon_rtx (mem
);
1975 /* This optimization is performed by faking a store to the
1976 memory at the end of the block. This doesn't work for
1977 unchanging memories because multiple stores to unchanging
1978 memory is illegal and alias analysis doesn't consider it. */
1979 if (RTX_UNCHANGING_P (canon_mem
))
1982 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1983 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1984 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1985 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1986 add_to_mem_set_list (pbi
, canon_mem
);
1993 /* Release a propagate_block_info struct. */
1996 free_propagate_block_info (pbi
)
1997 struct propagate_block_info
*pbi
;
1999 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2001 BITMAP_XFREE (pbi
->new_set
);
2003 #ifdef HAVE_conditional_execution
2004 splay_tree_delete (pbi
->reg_cond_dead
);
2005 BITMAP_XFREE (pbi
->reg_cond_reg
);
2008 if (pbi
->reg_next_use
)
2009 free (pbi
->reg_next_use
);
2014 /* Compute the registers live at the beginning of a basic block BB from
2015 those live at the end.
2017 When called, REG_LIVE contains those live at the end. On return, it
2018 contains those live at the beginning.
2020 LOCAL_SET, if non-null, will be set with all registers killed
2021 unconditionally by this basic block.
2022 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2023 killed conditionally by this basic block. If there is any unconditional
2024 set of a register, then the corresponding bit will be set in LOCAL_SET
2025 and cleared in COND_LOCAL_SET.
2026 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2027 case, the resulting set will be equal to the union of the two sets that
2028 would otherwise be computed.
2030 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2033 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2037 regset cond_local_set
;
2040 struct propagate_block_info
*pbi
;
2044 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2046 if (flags
& PROP_REG_INFO
)
2050 /* Process the regs live at the end of the block.
2051 Mark them as not local to any one basic block. */
2052 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2053 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2056 /* Scan the block an insn at a time from end to beginning. */
2059 for (insn
= bb
->end
;; insn
= prev
)
2061 /* If this is a call to `setjmp' et al, warn if any
2062 non-volatile datum is live. */
2063 if ((flags
& PROP_REG_INFO
)
2064 && GET_CODE (insn
) == CALL_INSN
2065 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2066 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2068 prev
= propagate_one_insn (pbi
, insn
);
2069 changed
|= NEXT_INSN (prev
) != insn
;
2071 if (insn
== bb
->head
)
2075 free_propagate_block_info (pbi
);
2080 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2081 (SET expressions whose destinations are registers dead after the insn).
2082 NEEDED is the regset that says which regs are alive after the insn.
2084 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2086 If X is the entire body of an insn, NOTES contains the reg notes
2087 pertaining to the insn. */
2090 insn_dead_p (pbi
, x
, call_ok
, notes
)
2091 struct propagate_block_info
*pbi
;
2094 rtx notes ATTRIBUTE_UNUSED
;
2096 enum rtx_code code
= GET_CODE (x
);
2099 /* As flow is invoked after combine, we must take existing AUTO_INC
2100 expressions into account. */
2101 for (; notes
; notes
= XEXP (notes
, 1))
2103 if (REG_NOTE_KIND (notes
) == REG_INC
)
2105 int regno
= REGNO (XEXP (notes
, 0));
2107 /* Don't delete insns to set global regs. */
2108 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2109 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2115 /* If setting something that's a reg or part of one,
2116 see if that register's altered value will be live. */
2120 rtx r
= SET_DEST (x
);
2123 if (GET_CODE (r
) == CC0
)
2124 return ! pbi
->cc0_live
;
2127 /* A SET that is a subroutine call cannot be dead. */
2128 if (GET_CODE (SET_SRC (x
)) == CALL
)
2134 /* Don't eliminate loads from volatile memory or volatile asms. */
2135 else if (volatile_refs_p (SET_SRC (x
)))
2138 if (GET_CODE (r
) == MEM
)
2142 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2145 canon_r
= canon_rtx (r
);
2147 /* Walk the set of memory locations we are currently tracking
2148 and see if one is an identical match to this memory location.
2149 If so, this memory write is dead (remember, we're walking
2150 backwards from the end of the block to the start). Since
2151 rtx_equal_p does not check the alias set or flags, we also
2152 must have the potential for them to conflict (anti_dependence). */
2153 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2154 if (anti_dependence (r
, XEXP (temp
, 0)))
2156 rtx mem
= XEXP (temp
, 0);
2158 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2159 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2160 <= GET_MODE_SIZE (GET_MODE (mem
))))
2164 /* Check if memory reference matches an auto increment. Only
2165 post increment/decrement or modify are valid. */
2166 if (GET_MODE (mem
) == GET_MODE (r
)
2167 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2168 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2169 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2170 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2171 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2178 while (GET_CODE (r
) == SUBREG
2179 || GET_CODE (r
) == STRICT_LOW_PART
2180 || GET_CODE (r
) == ZERO_EXTRACT
)
2183 if (GET_CODE (r
) == REG
)
2185 int regno
= REGNO (r
);
2188 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2191 /* If this is a hard register, verify that subsequent
2192 words are not needed. */
2193 if (regno
< FIRST_PSEUDO_REGISTER
)
2195 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2198 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2202 /* Don't delete insns to set global regs. */
2203 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2206 /* Make sure insns to set the stack pointer aren't deleted. */
2207 if (regno
== STACK_POINTER_REGNUM
)
2210 /* ??? These bits might be redundant with the force live bits
2211 in calculate_global_regs_live. We would delete from
2212 sequential sets; whether this actually affects real code
2213 for anything but the stack pointer I don't know. */
2214 /* Make sure insns to set the frame pointer aren't deleted. */
2215 if (regno
== FRAME_POINTER_REGNUM
2216 && (! reload_completed
|| frame_pointer_needed
))
2218 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2219 if (regno
== HARD_FRAME_POINTER_REGNUM
2220 && (! reload_completed
|| frame_pointer_needed
))
2224 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2225 /* Make sure insns to set arg pointer are never deleted
2226 (if the arg pointer isn't fixed, there will be a USE
2227 for it, so we can treat it normally). */
2228 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2232 /* Otherwise, the set is dead. */
2238 /* If performing several activities, insn is dead if each activity
2239 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2240 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2242 else if (code
== PARALLEL
)
2244 int i
= XVECLEN (x
, 0);
2246 for (i
--; i
>= 0; i
--)
2247 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2248 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2249 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2255 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2256 is not necessarily true for hard registers. */
2257 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2258 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2259 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2262 /* We do not check other CLOBBER or USE here. An insn consisting of just
2263 a CLOBBER or just a USE should not be deleted. */
2267 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2268 return 1 if the entire library call is dead.
2269 This is true if INSN copies a register (hard or pseudo)
2270 and if the hard return reg of the call insn is dead.
2271 (The caller should have tested the destination of the SET inside
2272 INSN already for death.)
2274 If this insn doesn't just copy a register, then we don't
2275 have an ordinary libcall. In that case, cse could not have
2276 managed to substitute the source for the dest later on,
2277 so we can assume the libcall is dead.
2279 PBI is the block info giving pseudoregs live before this insn.
2280 NOTE is the REG_RETVAL note of the insn. */
2283 libcall_dead_p (pbi
, note
, insn
)
2284 struct propagate_block_info
*pbi
;
2288 rtx x
= single_set (insn
);
2292 rtx r
= SET_SRC (x
);
2294 if (GET_CODE (r
) == REG
)
2296 rtx call
= XEXP (note
, 0);
2300 /* Find the call insn. */
2301 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2302 call
= NEXT_INSN (call
);
2304 /* If there is none, do nothing special,
2305 since ordinary death handling can understand these insns. */
2309 /* See if the hard reg holding the value is dead.
2310 If this is a PARALLEL, find the call within it. */
2311 call_pat
= PATTERN (call
);
2312 if (GET_CODE (call_pat
) == PARALLEL
)
2314 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2315 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2316 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2319 /* This may be a library call that is returning a value
2320 via invisible pointer. Do nothing special, since
2321 ordinary death handling can understand these insns. */
2325 call_pat
= XVECEXP (call_pat
, 0, i
);
2328 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2334 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2335 live at function entry. Don't count global register variables, variables
2336 in registers that can be used for function arg passing, or variables in
2337 fixed hard registers. */
2340 regno_uninitialized (regno
)
2343 if (n_basic_blocks
== 0
2344 || (regno
< FIRST_PSEUDO_REGISTER
2345 && (global_regs
[regno
]
2346 || fixed_regs
[regno
]
2347 || FUNCTION_ARG_REGNO_P (regno
))))
2350 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2353 /* 1 if register REGNO was alive at a place where `setjmp' was called
2354 and was set more than once or is an argument.
2355 Such regs may be clobbered by `longjmp'. */
2358 regno_clobbered_at_setjmp (regno
)
2361 if (n_basic_blocks
== 0)
2364 return ((REG_N_SETS (regno
) > 1
2365 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2366 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2369 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2370 maximal list size; look for overlaps in mode and select the largest. */
2372 add_to_mem_set_list (pbi
, mem
)
2373 struct propagate_block_info
*pbi
;
2378 /* We don't know how large a BLKmode store is, so we must not
2379 take them into consideration. */
2380 if (GET_MODE (mem
) == BLKmode
)
2383 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2385 rtx e
= XEXP (i
, 0);
2386 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2388 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2391 /* If we must store a copy of the mem, we can just modify
2392 the mode of the stored copy. */
2393 if (pbi
->flags
& PROP_AUTOINC
)
2394 PUT_MODE (e
, GET_MODE (mem
));
2403 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2406 /* Store a copy of mem, otherwise the address may be
2407 scrogged by find_auto_inc. */
2408 if (pbi
->flags
& PROP_AUTOINC
)
2409 mem
= shallow_copy_rtx (mem
);
2411 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2412 pbi
->mem_set_list_len
++;
2416 /* INSN references memory, possibly using autoincrement addressing modes.
2417 Find any entries on the mem_set_list that need to be invalidated due
2418 to an address change. */
2421 invalidate_mems_from_autoinc (px
, data
)
2426 struct propagate_block_info
*pbi
= data
;
2428 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2430 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2437 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2440 invalidate_mems_from_set (pbi
, exp
)
2441 struct propagate_block_info
*pbi
;
2444 rtx temp
= pbi
->mem_set_list
;
2445 rtx prev
= NULL_RTX
;
2450 next
= XEXP (temp
, 1);
2451 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2453 /* Splice this entry out of the list. */
2455 XEXP (prev
, 1) = next
;
2457 pbi
->mem_set_list
= next
;
2458 free_EXPR_LIST_node (temp
);
2459 pbi
->mem_set_list_len
--;
2467 /* Process the registers that are set within X. Their bits are set to
2468 1 in the regset DEAD, because they are dead prior to this insn.
2470 If INSN is nonzero, it is the insn being processed.
2472 FLAGS is the set of operations to perform. */
2475 mark_set_regs (pbi
, x
, insn
)
2476 struct propagate_block_info
*pbi
;
2479 rtx cond
= NULL_RTX
;
2484 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2486 if (REG_NOTE_KIND (link
) == REG_INC
)
2487 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2488 (GET_CODE (x
) == COND_EXEC
2489 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2493 switch (code
= GET_CODE (x
))
2497 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2501 cond
= COND_EXEC_TEST (x
);
2502 x
= COND_EXEC_CODE (x
);
2509 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2511 rtx sub
= XVECEXP (x
, 0, i
);
2512 switch (code
= GET_CODE (sub
))
2515 if (cond
!= NULL_RTX
)
2518 cond
= COND_EXEC_TEST (sub
);
2519 sub
= COND_EXEC_CODE (sub
);
2520 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2526 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2541 /* Process a single set, which appears in INSN. REG (which may not
2542 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2543 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2544 If the set is conditional (because it appear in a COND_EXEC), COND
2545 will be the condition. */
2548 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2549 struct propagate_block_info
*pbi
;
2551 rtx reg
, cond
, insn
;
2554 int regno_first
= -1, regno_last
= -1;
2555 unsigned long not_dead
= 0;
2558 /* Modifying just one hardware register of a multi-reg value or just a
2559 byte field of a register does not mean the value from before this insn
2560 is now dead. Of course, if it was dead after it's unused now. */
2562 switch (GET_CODE (reg
))
2565 /* Some targets place small structures in registers for return values of
2566 functions. We have to detect this case specially here to get correct
2567 flow information. */
2568 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2569 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2570 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2576 case STRICT_LOW_PART
:
2577 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2579 reg
= XEXP (reg
, 0);
2580 while (GET_CODE (reg
) == SUBREG
2581 || GET_CODE (reg
) == ZERO_EXTRACT
2582 || GET_CODE (reg
) == SIGN_EXTRACT
2583 || GET_CODE (reg
) == STRICT_LOW_PART
);
2584 if (GET_CODE (reg
) == MEM
)
2586 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2590 regno_last
= regno_first
= REGNO (reg
);
2591 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2592 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2596 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2598 enum machine_mode outer_mode
= GET_MODE (reg
);
2599 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2601 /* Identify the range of registers affected. This is moderately
2602 tricky for hard registers. See alter_subreg. */
2604 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2605 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2607 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2610 regno_last
= (regno_first
2611 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2613 /* Since we've just adjusted the register number ranges, make
2614 sure REG matches. Otherwise some_was_live will be clear
2615 when it shouldn't have been, and we'll create incorrect
2616 REG_UNUSED notes. */
2617 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2621 /* If the number of words in the subreg is less than the number
2622 of words in the full register, we have a well-defined partial
2623 set. Otherwise the high bits are undefined.
2625 This is only really applicable to pseudos, since we just took
2626 care of multi-word hard registers. */
2627 if (((GET_MODE_SIZE (outer_mode
)
2628 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2629 < ((GET_MODE_SIZE (inner_mode
)
2630 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2631 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2634 reg
= SUBREG_REG (reg
);
2638 reg
= SUBREG_REG (reg
);
2645 /* If this set is a MEM, then it kills any aliased writes.
2646 If this set is a REG, then it kills any MEMs which use the reg. */
2647 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2649 if (GET_CODE (reg
) == REG
)
2650 invalidate_mems_from_set (pbi
, reg
);
2652 /* If the memory reference had embedded side effects (autoincrement
2653 address modes. Then we may need to kill some entries on the
2655 if (insn
&& GET_CODE (reg
) == MEM
)
2656 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2658 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2659 /* ??? With more effort we could track conditional memory life. */
2661 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2664 if (GET_CODE (reg
) == REG
2665 && ! (regno_first
== FRAME_POINTER_REGNUM
2666 && (! reload_completed
|| frame_pointer_needed
))
2667 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2668 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2669 && (! reload_completed
|| frame_pointer_needed
))
2671 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2672 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2676 int some_was_live
= 0, some_was_dead
= 0;
2678 for (i
= regno_first
; i
<= regno_last
; ++i
)
2680 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2683 /* Order of the set operation matters here since both
2684 sets may be the same. */
2685 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2686 if (cond
!= NULL_RTX
2687 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2688 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2690 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2692 if (code
!= CLOBBER
)
2693 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2695 some_was_live
|= needed_regno
;
2696 some_was_dead
|= ! needed_regno
;
2699 #ifdef HAVE_conditional_execution
2700 /* Consider conditional death in deciding that the register needs
2702 if (some_was_live
&& ! not_dead
2703 /* The stack pointer is never dead. Well, not strictly true,
2704 but it's very difficult to tell from here. Hopefully
2705 combine_stack_adjustments will fix up the most egregious
2707 && regno_first
!= STACK_POINTER_REGNUM
)
2709 for (i
= regno_first
; i
<= regno_last
; ++i
)
2710 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2711 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2715 /* Additional data to record if this is the final pass. */
2716 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2717 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2720 int blocknum
= pbi
->bb
->index
;
2723 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2725 y
= pbi
->reg_next_use
[regno_first
];
2727 /* The next use is no longer next, since a store intervenes. */
2728 for (i
= regno_first
; i
<= regno_last
; ++i
)
2729 pbi
->reg_next_use
[i
] = 0;
2732 if (flags
& PROP_REG_INFO
)
2734 for (i
= regno_first
; i
<= regno_last
; ++i
)
2736 /* Count (weighted) references, stores, etc. This counts a
2737 register twice if it is modified, but that is correct. */
2738 REG_N_SETS (i
) += 1;
2739 REG_N_REFS (i
) += 1;
2740 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2742 /* The insns where a reg is live are normally counted
2743 elsewhere, but we want the count to include the insn
2744 where the reg is set, and the normal counting mechanism
2745 would not count it. */
2746 REG_LIVE_LENGTH (i
) += 1;
2749 /* If this is a hard reg, record this function uses the reg. */
2750 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2752 for (i
= regno_first
; i
<= regno_last
; i
++)
2753 regs_ever_live
[i
] = 1;
2757 /* Keep track of which basic blocks each reg appears in. */
2758 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2759 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2760 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2761 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2765 if (! some_was_dead
)
2767 if (flags
& PROP_LOG_LINKS
)
2769 /* Make a logical link from the next following insn
2770 that uses this register, back to this insn.
2771 The following insns have already been processed.
2773 We don't build a LOG_LINK for hard registers containing
2774 in ASM_OPERANDs. If these registers get replaced,
2775 we might wind up changing the semantics of the insn,
2776 even if reload can make what appear to be valid
2777 assignments later. */
2778 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2779 && (regno_first
>= FIRST_PSEUDO_REGISTER
2780 || asm_noperands (PATTERN (y
)) < 0))
2781 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2786 else if (! some_was_live
)
2788 if (flags
& PROP_REG_INFO
)
2789 REG_N_DEATHS (regno_first
) += 1;
2791 if (flags
& PROP_DEATH_NOTES
)
2793 /* Note that dead stores have already been deleted
2794 when possible. If we get here, we have found a
2795 dead store that cannot be eliminated (because the
2796 same insn does something useful). Indicate this
2797 by marking the reg being set as dying here. */
2799 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2804 if (flags
& PROP_DEATH_NOTES
)
2806 /* This is a case where we have a multi-word hard register
2807 and some, but not all, of the words of the register are
2808 needed in subsequent insns. Write REG_UNUSED notes
2809 for those parts that were not needed. This case should
2812 for (i
= regno_first
; i
<= regno_last
; ++i
)
2813 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2815 = alloc_EXPR_LIST (REG_UNUSED
,
2816 gen_rtx_REG (reg_raw_mode
[i
], i
),
2822 /* Mark the register as being dead. */
2824 /* The stack pointer is never dead. Well, not strictly true,
2825 but it's very difficult to tell from here. Hopefully
2826 combine_stack_adjustments will fix up the most egregious
2828 && regno_first
!= STACK_POINTER_REGNUM
)
2830 for (i
= regno_first
; i
<= regno_last
; ++i
)
2831 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2832 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2835 else if (GET_CODE (reg
) == REG
)
2837 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2838 pbi
->reg_next_use
[regno_first
] = 0;
2841 /* If this is the last pass and this is a SCRATCH, show it will be dying
2842 here and count it. */
2843 else if (GET_CODE (reg
) == SCRATCH
)
2845 if (flags
& PROP_DEATH_NOTES
)
2847 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2851 #ifdef HAVE_conditional_execution
2852 /* Mark REGNO conditionally dead.
2853 Return true if the register is now unconditionally dead. */
2856 mark_regno_cond_dead (pbi
, regno
, cond
)
2857 struct propagate_block_info
*pbi
;
2861 /* If this is a store to a predicate register, the value of the
2862 predicate is changing, we don't know that the predicate as seen
2863 before is the same as that seen after. Flush all dependent
2864 conditions from reg_cond_dead. This will make all such
2865 conditionally live registers unconditionally live. */
2866 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2867 flush_reg_cond_reg (pbi
, regno
);
2869 /* If this is an unconditional store, remove any conditional
2870 life that may have existed. */
2871 if (cond
== NULL_RTX
)
2872 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2875 splay_tree_node node
;
2876 struct reg_cond_life_info
*rcli
;
2879 /* Otherwise this is a conditional set. Record that fact.
2880 It may have been conditionally used, or there may be a
2881 subsequent set with a complimentary condition. */
2883 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2886 /* The register was unconditionally live previously.
2887 Record the current condition as the condition under
2888 which it is dead. */
2889 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2890 rcli
->condition
= cond
;
2891 rcli
->stores
= cond
;
2892 rcli
->orig_condition
= const0_rtx
;
2893 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2894 (splay_tree_value
) rcli
);
2896 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2898 /* Not unconditionally dead. */
2903 /* The register was conditionally live previously.
2904 Add the new condition to the old. */
2905 rcli
= (struct reg_cond_life_info
*) node
->value
;
2906 ncond
= rcli
->condition
;
2907 ncond
= ior_reg_cond (ncond
, cond
, 1);
2908 if (rcli
->stores
== const0_rtx
)
2909 rcli
->stores
= cond
;
2910 else if (rcli
->stores
!= const1_rtx
)
2911 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2913 /* If the register is now unconditionally dead, remove the entry
2914 in the splay_tree. A register is unconditionally dead if the
2915 dead condition ncond is true. A register is also unconditionally
2916 dead if the sum of all conditional stores is an unconditional
2917 store (stores is true), and the dead condition is identically the
2918 same as the original dead condition initialized at the end of
2919 the block. This is a pointer compare, not an rtx_equal_p
2921 if (ncond
== const1_rtx
2922 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2923 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2926 rcli
->condition
= ncond
;
2928 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2930 /* Not unconditionally dead. */
2939 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2942 free_reg_cond_life_info (value
)
2943 splay_tree_value value
;
2945 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2949 /* Helper function for flush_reg_cond_reg. */
2952 flush_reg_cond_reg_1 (node
, data
)
2953 splay_tree_node node
;
2956 struct reg_cond_life_info
*rcli
;
2957 int *xdata
= (int *) data
;
2958 unsigned int regno
= xdata
[0];
2960 /* Don't need to search if last flushed value was farther on in
2961 the in-order traversal. */
2962 if (xdata
[1] >= (int) node
->key
)
2965 /* Splice out portions of the expression that refer to regno. */
2966 rcli
= (struct reg_cond_life_info
*) node
->value
;
2967 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2968 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2969 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2971 /* If the entire condition is now false, signal the node to be removed. */
2972 if (rcli
->condition
== const0_rtx
)
2974 xdata
[1] = node
->key
;
2977 else if (rcli
->condition
== const1_rtx
)
2983 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2986 flush_reg_cond_reg (pbi
, regno
)
2987 struct propagate_block_info
*pbi
;
2994 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2995 flush_reg_cond_reg_1
, pair
) == -1)
2996 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
2998 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3001 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3002 For ior/and, the ADD flag determines whether we want to add the new
3003 condition X to the old one unconditionally. If it is zero, we will
3004 only return a new expression if X allows us to simplify part of
3005 OLD, otherwise we return NULL to the caller.
3006 If ADD is nonzero, we will return a new condition in all cases. The
3007 toplevel caller of one of these functions should always pass 1 for
3011 ior_reg_cond (old
, x
, add
)
3017 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3019 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3020 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3021 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3023 if (GET_CODE (x
) == GET_CODE (old
)
3024 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3028 return gen_rtx_IOR (0, old
, x
);
3031 switch (GET_CODE (old
))
3034 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3035 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3036 if (op0
!= NULL
|| op1
!= NULL
)
3038 if (op0
== const0_rtx
)
3039 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3040 if (op1
== const0_rtx
)
3041 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3042 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3045 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3046 else if (rtx_equal_p (x
, op0
))
3047 /* (x | A) | x ~ (x | A). */
3050 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3051 else if (rtx_equal_p (x
, op1
))
3052 /* (A | x) | x ~ (A | x). */
3054 return gen_rtx_IOR (0, op0
, op1
);
3058 return gen_rtx_IOR (0, old
, x
);
3061 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3062 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3063 if (op0
!= NULL
|| op1
!= NULL
)
3065 if (op0
== const1_rtx
)
3066 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3067 if (op1
== const1_rtx
)
3068 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3069 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3072 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3073 else if (rtx_equal_p (x
, op0
))
3074 /* (x & A) | x ~ x. */
3077 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3078 else if (rtx_equal_p (x
, op1
))
3079 /* (A & x) | x ~ x. */
3081 return gen_rtx_AND (0, op0
, op1
);
3085 return gen_rtx_IOR (0, old
, x
);
3088 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3090 return not_reg_cond (op0
);
3093 return gen_rtx_IOR (0, old
, x
);
3104 enum rtx_code x_code
;
3106 if (x
== const0_rtx
)
3108 else if (x
== const1_rtx
)
3110 x_code
= GET_CODE (x
);
3113 if (GET_RTX_CLASS (x_code
) == '<'
3114 && GET_CODE (XEXP (x
, 0)) == REG
)
3116 if (XEXP (x
, 1) != const0_rtx
)
3119 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3120 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3122 return gen_rtx_NOT (0, x
);
3126 and_reg_cond (old
, x
, add
)
3132 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3134 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3135 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3136 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3138 if (GET_CODE (x
) == GET_CODE (old
)
3139 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3143 return gen_rtx_AND (0, old
, x
);
3146 switch (GET_CODE (old
))
3149 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3150 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3151 if (op0
!= NULL
|| op1
!= NULL
)
3153 if (op0
== const0_rtx
)
3154 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3155 if (op1
== const0_rtx
)
3156 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3157 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3160 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3161 else if (rtx_equal_p (x
, op0
))
3162 /* (x | A) & x ~ x. */
3165 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3166 else if (rtx_equal_p (x
, op1
))
3167 /* (A | x) & x ~ x. */
3169 return gen_rtx_IOR (0, op0
, op1
);
3173 return gen_rtx_AND (0, old
, x
);
3176 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3177 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3178 if (op0
!= NULL
|| op1
!= NULL
)
3180 if (op0
== const1_rtx
)
3181 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3182 if (op1
== const1_rtx
)
3183 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3184 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3187 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3188 else if (rtx_equal_p (x
, op0
))
3189 /* (x & A) & x ~ (x & A). */
3192 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3193 else if (rtx_equal_p (x
, op1
))
3194 /* (A & x) & x ~ (A & x). */
3196 return gen_rtx_AND (0, op0
, op1
);
3200 return gen_rtx_AND (0, old
, x
);
3203 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3205 return not_reg_cond (op0
);
3208 return gen_rtx_AND (0, old
, x
);
3215 /* Given a condition X, remove references to reg REGNO and return the
3216 new condition. The removal will be done so that all conditions
3217 involving REGNO are considered to evaluate to false. This function
3218 is used when the value of REGNO changes. */
3221 elim_reg_cond (x
, regno
)
3227 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3229 if (REGNO (XEXP (x
, 0)) == regno
)
3234 switch (GET_CODE (x
))
3237 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3238 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3239 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3241 if (op0
== const1_rtx
)
3243 if (op1
== const1_rtx
)
3245 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3247 return gen_rtx_AND (0, op0
, op1
);
3250 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3251 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3252 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3254 if (op0
== const0_rtx
)
3256 if (op1
== const0_rtx
)
3258 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3260 return gen_rtx_IOR (0, op0
, op1
);
3263 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3264 if (op0
== const0_rtx
)
3266 if (op0
== const1_rtx
)
3268 if (op0
!= XEXP (x
, 0))
3269 return not_reg_cond (op0
);
3276 #endif /* HAVE_conditional_execution */
3280 /* Try to substitute the auto-inc expression INC as the address inside
3281 MEM which occurs in INSN. Currently, the address of MEM is an expression
3282 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3283 that has a single set whose source is a PLUS of INCR_REG and something
3287 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3288 struct propagate_block_info
*pbi
;
3289 rtx inc
, insn
, mem
, incr
, incr_reg
;
3291 int regno
= REGNO (incr_reg
);
3292 rtx set
= single_set (incr
);
3293 rtx q
= SET_DEST (set
);
3294 rtx y
= SET_SRC (set
);
3295 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3297 /* Make sure this reg appears only once in this insn. */
3298 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3301 if (dead_or_set_p (incr
, incr_reg
)
3302 /* Mustn't autoinc an eliminable register. */
3303 && (regno
>= FIRST_PSEUDO_REGISTER
3304 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3306 /* This is the simple case. Try to make the auto-inc. If
3307 we can't, we are done. Otherwise, we will do any
3308 needed updates below. */
3309 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3312 else if (GET_CODE (q
) == REG
3313 /* PREV_INSN used here to check the semi-open interval
3315 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3316 /* We must also check for sets of q as q may be
3317 a call clobbered hard register and there may
3318 be a call between PREV_INSN (insn) and incr. */
3319 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3321 /* We have *p followed sometime later by q = p+size.
3322 Both p and q must be live afterward,
3323 and q is not used between INSN and its assignment.
3324 Change it to q = p, ...*q..., q = q+size.
3325 Then fall into the usual case. */
3329 emit_move_insn (q
, incr_reg
);
3330 insns
= get_insns ();
3333 /* If we can't make the auto-inc, or can't make the
3334 replacement into Y, exit. There's no point in making
3335 the change below if we can't do the auto-inc and doing
3336 so is not correct in the pre-inc case. */
3339 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3340 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3341 if (! apply_change_group ())
3344 /* We now know we'll be doing this change, so emit the
3345 new insn(s) and do the updates. */
3346 emit_insns_before (insns
, insn
);
3348 if (pbi
->bb
->head
== insn
)
3349 pbi
->bb
->head
= insns
;
3351 /* INCR will become a NOTE and INSN won't contain a
3352 use of INCR_REG. If a use of INCR_REG was just placed in
3353 the insn before INSN, make that the next use.
3354 Otherwise, invalidate it. */
3355 if (GET_CODE (PREV_INSN (insn
)) == INSN
3356 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3357 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3358 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3360 pbi
->reg_next_use
[regno
] = 0;
3365 /* REGNO is now used in INCR which is below INSN, but
3366 it previously wasn't live here. If we don't mark
3367 it as live, we'll put a REG_DEAD note for it
3368 on this insn, which is incorrect. */
3369 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3371 /* If there are any calls between INSN and INCR, show
3372 that REGNO now crosses them. */
3373 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3374 if (GET_CODE (temp
) == CALL_INSN
)
3375 REG_N_CALLS_CROSSED (regno
)++;
3377 /* Invalidate alias info for Q since we just changed its value. */
3378 clear_reg_alias_info (q
);
3383 /* If we haven't returned, it means we were able to make the
3384 auto-inc, so update the status. First, record that this insn
3385 has an implicit side effect. */
3387 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3389 /* Modify the old increment-insn to simply copy
3390 the already-incremented value of our register. */
3391 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3394 /* If that makes it a no-op (copying the register into itself) delete
3395 it so it won't appear to be a "use" and a "set" of this
3397 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3399 /* If the original source was dead, it's dead now. */
3402 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3404 remove_note (incr
, note
);
3405 if (XEXP (note
, 0) != incr_reg
)
3406 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3409 PUT_CODE (incr
, NOTE
);
3410 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3411 NOTE_SOURCE_FILE (incr
) = 0;
3414 if (regno
>= FIRST_PSEUDO_REGISTER
)
3416 /* Count an extra reference to the reg. When a reg is
3417 incremented, spilling it is worse, so we want to make
3418 that less likely. */
3419 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3421 /* Count the increment as a setting of the register,
3422 even though it isn't a SET in rtl. */
3423 REG_N_SETS (regno
)++;
3427 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3431 find_auto_inc (pbi
, x
, insn
)
3432 struct propagate_block_info
*pbi
;
3436 rtx addr
= XEXP (x
, 0);
3437 HOST_WIDE_INT offset
= 0;
3438 rtx set
, y
, incr
, inc_val
;
3440 int size
= GET_MODE_SIZE (GET_MODE (x
));
3442 if (GET_CODE (insn
) == JUMP_INSN
)
3445 /* Here we detect use of an index register which might be good for
3446 postincrement, postdecrement, preincrement, or predecrement. */
3448 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3449 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3451 if (GET_CODE (addr
) != REG
)
3454 regno
= REGNO (addr
);
3456 /* Is the next use an increment that might make auto-increment? */
3457 incr
= pbi
->reg_next_use
[regno
];
3458 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3460 set
= single_set (incr
);
3461 if (set
== 0 || GET_CODE (set
) != SET
)
3465 if (GET_CODE (y
) != PLUS
)
3468 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3469 inc_val
= XEXP (y
, 1);
3470 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3471 inc_val
= XEXP (y
, 0);
3475 if (GET_CODE (inc_val
) == CONST_INT
)
3477 if (HAVE_POST_INCREMENT
3478 && (INTVAL (inc_val
) == size
&& offset
== 0))
3479 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3481 else if (HAVE_POST_DECREMENT
3482 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3483 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3485 else if (HAVE_PRE_INCREMENT
3486 && (INTVAL (inc_val
) == size
&& offset
== size
))
3487 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3489 else if (HAVE_PRE_DECREMENT
3490 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3491 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3493 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3494 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3495 gen_rtx_PLUS (Pmode
,
3498 insn
, x
, incr
, addr
);
3500 else if (GET_CODE (inc_val
) == REG
3501 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3505 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3506 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3507 gen_rtx_PLUS (Pmode
,
3510 insn
, x
, incr
, addr
);
3514 #endif /* AUTO_INC_DEC */
3517 mark_used_reg (pbi
, reg
, cond
, insn
)
3518 struct propagate_block_info
*pbi
;
3520 rtx cond ATTRIBUTE_UNUSED
;
3523 unsigned int regno_first
, regno_last
, i
;
3524 int some_was_live
, some_was_dead
, some_not_set
;
3526 regno_last
= regno_first
= REGNO (reg
);
3527 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3528 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3530 /* Find out if any of this register is live after this instruction. */
3531 some_was_live
= some_was_dead
= 0;
3532 for (i
= regno_first
; i
<= regno_last
; ++i
)
3534 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3535 some_was_live
|= needed_regno
;
3536 some_was_dead
|= ! needed_regno
;
3539 /* Find out if any of the register was set this insn. */
3541 for (i
= regno_first
; i
<= regno_last
; ++i
)
3542 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3544 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3546 /* Record where each reg is used, so when the reg is set we know
3547 the next insn that uses it. */
3548 pbi
->reg_next_use
[regno_first
] = insn
;
3551 if (pbi
->flags
& PROP_REG_INFO
)
3553 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3555 /* If this is a register we are going to try to eliminate,
3556 don't mark it live here. If we are successful in
3557 eliminating it, it need not be live unless it is used for
3558 pseudos, in which case it will have been set live when it
3559 was allocated to the pseudos. If the register will not
3560 be eliminated, reload will set it live at that point.
3562 Otherwise, record that this function uses this register. */
3563 /* ??? The PPC backend tries to "eliminate" on the pic
3564 register to itself. This should be fixed. In the mean
3565 time, hack around it. */
3567 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3568 && (regno_first
== FRAME_POINTER_REGNUM
3569 || regno_first
== ARG_POINTER_REGNUM
)))
3570 for (i
= regno_first
; i
<= regno_last
; ++i
)
3571 regs_ever_live
[i
] = 1;
3575 /* Keep track of which basic block each reg appears in. */
3577 int blocknum
= pbi
->bb
->index
;
3578 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3579 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3580 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3581 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3583 /* Count (weighted) number of uses of each reg. */
3584 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3585 REG_N_REFS (regno_first
)++;
3589 /* Record and count the insns in which a reg dies. If it is used in
3590 this insn and was dead below the insn then it dies in this insn.
3591 If it was set in this insn, we do not make a REG_DEAD note;
3592 likewise if we already made such a note. */
3593 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3597 /* Check for the case where the register dying partially
3598 overlaps the register set by this insn. */
3599 if (regno_first
!= regno_last
)
3600 for (i
= regno_first
; i
<= regno_last
; ++i
)
3601 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3603 /* If none of the words in X is needed, make a REG_DEAD note.
3604 Otherwise, we must make partial REG_DEAD notes. */
3605 if (! some_was_live
)
3607 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3608 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3610 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3612 if (pbi
->flags
& PROP_REG_INFO
)
3613 REG_N_DEATHS (regno_first
)++;
3617 /* Don't make a REG_DEAD note for a part of a register
3618 that is set in the insn. */
3619 for (i
= regno_first
; i
<= regno_last
; ++i
)
3620 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3621 && ! dead_or_set_regno_p (insn
, i
))
3623 = alloc_EXPR_LIST (REG_DEAD
,
3624 gen_rtx_REG (reg_raw_mode
[i
], i
),
3629 /* Mark the register as being live. */
3630 for (i
= regno_first
; i
<= regno_last
; ++i
)
3632 #ifdef HAVE_conditional_execution
3633 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3636 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3638 #ifdef HAVE_conditional_execution
3639 /* If this is a conditional use, record that fact. If it is later
3640 conditionally set, we'll know to kill the register. */
3641 if (cond
!= NULL_RTX
)
3643 splay_tree_node node
;
3644 struct reg_cond_life_info
*rcli
;
3649 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3652 /* The register was unconditionally live previously.
3653 No need to do anything. */
3657 /* The register was conditionally live previously.
3658 Subtract the new life cond from the old death cond. */
3659 rcli
= (struct reg_cond_life_info
*) node
->value
;
3660 ncond
= rcli
->condition
;
3661 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3663 /* If the register is now unconditionally live,
3664 remove the entry in the splay_tree. */
3665 if (ncond
== const0_rtx
)
3666 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3669 rcli
->condition
= ncond
;
3670 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3671 REGNO (XEXP (cond
, 0)));
3677 /* The register was not previously live at all. Record
3678 the condition under which it is still dead. */
3679 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3680 rcli
->condition
= not_reg_cond (cond
);
3681 rcli
->stores
= const0_rtx
;
3682 rcli
->orig_condition
= const0_rtx
;
3683 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3684 (splay_tree_value
) rcli
);
3686 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3689 else if (this_was_live
)
3691 /* The register may have been conditionally live previously, but
3692 is now unconditionally live. Remove it from the conditionally
3693 dead list, so that a conditional set won't cause us to think
3695 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3701 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3702 This is done assuming the registers needed from X are those that
3703 have 1-bits in PBI->REG_LIVE.
3705 INSN is the containing instruction. If INSN is dead, this function
3709 mark_used_regs (pbi
, x
, cond
, insn
)
3710 struct propagate_block_info
*pbi
;
3715 int flags
= pbi
->flags
;
3720 code
= GET_CODE (x
);
3741 /* If we are clobbering a MEM, mark any registers inside the address
3743 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3744 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3748 /* Don't bother watching stores to mems if this is not the
3749 final pass. We'll not be deleting dead stores this round. */
3750 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3752 /* Invalidate the data for the last MEM stored, but only if MEM is
3753 something that can be stored into. */
3754 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3755 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3756 /* Needn't clear the memory set list. */
3760 rtx temp
= pbi
->mem_set_list
;
3761 rtx prev
= NULL_RTX
;
3766 next
= XEXP (temp
, 1);
3767 if (anti_dependence (XEXP (temp
, 0), x
))
3769 /* Splice temp out of the list. */
3771 XEXP (prev
, 1) = next
;
3773 pbi
->mem_set_list
= next
;
3774 free_EXPR_LIST_node (temp
);
3775 pbi
->mem_set_list_len
--;
3783 /* If the memory reference had embedded side effects (autoincrement
3784 address modes. Then we may need to kill some entries on the
3787 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3791 if (flags
& PROP_AUTOINC
)
3792 find_auto_inc (pbi
, x
, insn
);
3797 #ifdef CLASS_CANNOT_CHANGE_MODE
3798 if (GET_CODE (SUBREG_REG (x
)) == REG
3799 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3800 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3801 GET_MODE (SUBREG_REG (x
))))
3802 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3805 /* While we're here, optimize this case. */
3807 if (GET_CODE (x
) != REG
)
3812 /* See a register other than being set => mark it as needed. */
3813 mark_used_reg (pbi
, x
, cond
, insn
);
3818 rtx testreg
= SET_DEST (x
);
3821 /* If storing into MEM, don't show it as being used. But do
3822 show the address as being used. */
3823 if (GET_CODE (testreg
) == MEM
)
3826 if (flags
& PROP_AUTOINC
)
3827 find_auto_inc (pbi
, testreg
, insn
);
3829 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3830 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3834 /* Storing in STRICT_LOW_PART is like storing in a reg
3835 in that this SET might be dead, so ignore it in TESTREG.
3836 but in some other ways it is like using the reg.
3838 Storing in a SUBREG or a bit field is like storing the entire
3839 register in that if the register's value is not used
3840 then this SET is not needed. */
3841 while (GET_CODE (testreg
) == STRICT_LOW_PART
3842 || GET_CODE (testreg
) == ZERO_EXTRACT
3843 || GET_CODE (testreg
) == SIGN_EXTRACT
3844 || GET_CODE (testreg
) == SUBREG
)
3846 #ifdef CLASS_CANNOT_CHANGE_MODE
3847 if (GET_CODE (testreg
) == SUBREG
3848 && GET_CODE (SUBREG_REG (testreg
)) == REG
3849 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3850 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3851 GET_MODE (testreg
)))
3852 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3855 /* Modifying a single register in an alternate mode
3856 does not use any of the old value. But these other
3857 ways of storing in a register do use the old value. */
3858 if (GET_CODE (testreg
) == SUBREG
3859 && !((REG_BYTES (SUBREG_REG (testreg
))
3860 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3861 > (REG_BYTES (testreg
)
3862 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3867 testreg
= XEXP (testreg
, 0);
3870 /* If this is a store into a register or group of registers,
3871 recursively scan the value being stored. */
3873 if ((GET_CODE (testreg
) == PARALLEL
3874 && GET_MODE (testreg
) == BLKmode
)
3875 || (GET_CODE (testreg
) == REG
3876 && (regno
= REGNO (testreg
),
3877 ! (regno
== FRAME_POINTER_REGNUM
3878 && (! reload_completed
|| frame_pointer_needed
)))
3879 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3880 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3881 && (! reload_completed
|| frame_pointer_needed
))
3883 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3884 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3889 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3890 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3897 case UNSPEC_VOLATILE
:
3901 /* Traditional and volatile asm instructions must be considered to use
3902 and clobber all hard registers, all pseudo-registers and all of
3903 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3905 Consider for instance a volatile asm that changes the fpu rounding
3906 mode. An insn should not be moved across this even if it only uses
3907 pseudo-regs because it might give an incorrectly rounded result.
3909 ?!? Unfortunately, marking all hard registers as live causes massive
3910 problems for the register allocator and marking all pseudos as live
3911 creates mountains of uninitialized variable warnings.
3913 So for now, just clear the memory set list and mark any regs
3914 we can find in ASM_OPERANDS as used. */
3915 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3917 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3918 pbi
->mem_set_list_len
= 0;
3921 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3922 We can not just fall through here since then we would be confused
3923 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3924 traditional asms unlike their normal usage. */
3925 if (code
== ASM_OPERANDS
)
3929 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3930 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3936 if (cond
!= NULL_RTX
)
3939 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3941 cond
= COND_EXEC_TEST (x
);
3942 x
= COND_EXEC_CODE (x
);
3946 /* We _do_not_ want to scan operands of phi nodes. Operands of
3947 a phi function are evaluated only when control reaches this
3948 block along a particular edge. Therefore, regs that appear
3949 as arguments to phi should not be added to the global live at
3957 /* Recursively scan the operands of this expression. */
3960 const char * const fmt
= GET_RTX_FORMAT (code
);
3963 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3967 /* Tail recursive case: save a function call level. */
3973 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3975 else if (fmt
[i
] == 'E')
3978 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3979 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3988 try_pre_increment_1 (pbi
, insn
)
3989 struct propagate_block_info
*pbi
;
3992 /* Find the next use of this reg. If in same basic block,
3993 make it do pre-increment or pre-decrement if appropriate. */
3994 rtx x
= single_set (insn
);
3995 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3996 * INTVAL (XEXP (SET_SRC (x
), 1)));
3997 int regno
= REGNO (SET_DEST (x
));
3998 rtx y
= pbi
->reg_next_use
[regno
];
4000 && SET_DEST (x
) != stack_pointer_rtx
4001 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4002 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4003 mode would be better. */
4004 && ! dead_or_set_p (y
, SET_DEST (x
))
4005 && try_pre_increment (y
, SET_DEST (x
), amount
))
4007 /* We have found a suitable auto-increment and already changed
4008 insn Y to do it. So flush this increment instruction. */
4009 propagate_block_delete_insn (insn
);
4011 /* Count a reference to this reg for the increment insn we are
4012 deleting. When a reg is incremented, spilling it is worse,
4013 so we want to make that less likely. */
4014 if (regno
>= FIRST_PSEUDO_REGISTER
)
4016 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4017 REG_N_SETS (regno
)++;
4020 /* Flush any remembered memories depending on the value of
4021 the incremented register. */
4022 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4029 /* Try to change INSN so that it does pre-increment or pre-decrement
4030 addressing on register REG in order to add AMOUNT to REG.
4031 AMOUNT is negative for pre-decrement.
4032 Returns 1 if the change could be made.
4033 This checks all about the validity of the result of modifying INSN. */
4036 try_pre_increment (insn
, reg
, amount
)
4038 HOST_WIDE_INT amount
;
4042 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4043 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4045 /* Nonzero if we can try to make a post-increment or post-decrement.
4046 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4047 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4048 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4051 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4054 /* From the sign of increment, see which possibilities are conceivable
4055 on this target machine. */
4056 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4058 if (HAVE_POST_INCREMENT
&& amount
> 0)
4061 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4063 if (HAVE_POST_DECREMENT
&& amount
< 0)
4066 if (! (pre_ok
|| post_ok
))
4069 /* It is not safe to add a side effect to a jump insn
4070 because if the incremented register is spilled and must be reloaded
4071 there would be no way to store the incremented value back in memory. */
4073 if (GET_CODE (insn
) == JUMP_INSN
)
4078 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4079 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4081 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4085 if (use
== 0 || use
== (rtx
) (size_t) 1)
4088 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4091 /* See if this combination of instruction and addressing mode exists. */
4092 if (! validate_change (insn
, &XEXP (use
, 0),
4093 gen_rtx_fmt_e (amount
> 0
4094 ? (do_post
? POST_INC
: PRE_INC
)
4095 : (do_post
? POST_DEC
: PRE_DEC
),
4099 /* Record that this insn now has an implicit side effect on X. */
4100 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4104 #endif /* AUTO_INC_DEC */
4106 /* Find the place in the rtx X where REG is used as a memory address.
4107 Return the MEM rtx that so uses it.
4108 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4109 (plus REG (const_int PLUSCONST)).
4111 If such an address does not appear, return 0.
4112 If REG appears more than once, or is used other than in such an address,
4116 find_use_as_address (x
, reg
, plusconst
)
4119 HOST_WIDE_INT plusconst
;
4121 enum rtx_code code
= GET_CODE (x
);
4122 const char * const fmt
= GET_RTX_FORMAT (code
);
4127 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4130 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4131 && XEXP (XEXP (x
, 0), 0) == reg
4132 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4133 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4136 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4138 /* If REG occurs inside a MEM used in a bit-field reference,
4139 that is unacceptable. */
4140 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4141 return (rtx
) (size_t) 1;
4145 return (rtx
) (size_t) 1;
4147 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4151 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4155 return (rtx
) (size_t) 1;
4157 else if (fmt
[i
] == 'E')
4160 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4162 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4166 return (rtx
) (size_t) 1;
4174 /* Write information about registers and basic blocks into FILE.
4175 This is part of making a debugging dump. */
4178 dump_regset (r
, outf
)
4185 fputs (" (nil)", outf
);
4189 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4191 fprintf (outf
, " %d", i
);
4192 if (i
< FIRST_PSEUDO_REGISTER
)
4193 fprintf (outf
, " [%s]",
4198 /* Print a human-reaable representation of R on the standard error
4199 stream. This function is designed to be used from within the
4206 dump_regset (r
, stderr
);
4207 putc ('\n', stderr
);
4210 /* Recompute register set/reference counts immediately prior to register
4213 This avoids problems with set/reference counts changing to/from values
4214 which have special meanings to the register allocators.
4216 Additionally, the reference counts are the primary component used by the
4217 register allocators to prioritize pseudos for allocation to hard regs.
4218 More accurate reference counts generally lead to better register allocation.
4220 F is the first insn to be scanned.
4222 LOOP_STEP denotes how much loop_depth should be incremented per
4223 loop nesting level in order to increase the ref count more for
4224 references in a loop.
4226 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4227 possibly other information which is used by the register allocators. */
4230 recompute_reg_usage (f
, loop_step
)
4231 rtx f ATTRIBUTE_UNUSED
;
4232 int loop_step ATTRIBUTE_UNUSED
;
4234 allocate_reg_life_data ();
4235 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4238 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4239 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4240 of the number of registers that died. */
4243 count_or_remove_death_notes (blocks
, kill
)
4250 FOR_EACH_BB_REVERSE (bb
)
4254 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4257 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4261 rtx
*pprev
= ®_NOTES (insn
);
4266 switch (REG_NOTE_KIND (link
))
4269 if (GET_CODE (XEXP (link
, 0)) == REG
)
4271 rtx reg
= XEXP (link
, 0);
4274 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4277 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4285 rtx next
= XEXP (link
, 1);
4286 free_EXPR_LIST_node (link
);
4287 *pprev
= link
= next
;
4293 pprev
= &XEXP (link
, 1);
4300 if (insn
== bb
->end
)
4307 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4308 if blocks is NULL. */
4311 clear_log_links (blocks
)
4319 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4321 free_INSN_LIST_list (&LOG_LINKS (insn
));
4324 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4326 basic_block bb
= BASIC_BLOCK (i
);
4328 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4329 insn
= NEXT_INSN (insn
))
4331 free_INSN_LIST_list (&LOG_LINKS (insn
));
4335 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4336 correspond to the hard registers, if any, set in that map. This
4337 could be done far more efficiently by having all sorts of special-cases
4338 with moving single words, but probably isn't worth the trouble. */
4341 reg_set_to_hard_reg_set (to
, from
)
4347 EXECUTE_IF_SET_IN_BITMAP
4350 if (i
>= FIRST_PSEUDO_REGISTER
)
4352 SET_HARD_REG_BIT (*to
, i
);