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
);
771 if (bb
->flags
& BB_DIRTY
)
773 SET_BIT (update_life_blocks
, bb
->index
);
778 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
780 sbitmap_free (update_life_blocks
);
784 /* Free the variables allocated by find_basic_blocks.
786 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
789 free_basic_block_vars (keep_head_end_p
)
792 if (! keep_head_end_p
)
794 if (basic_block_info
)
797 VARRAY_FREE (basic_block_info
);
800 last_basic_block
= 0;
802 ENTRY_BLOCK_PTR
->aux
= NULL
;
803 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
804 EXIT_BLOCK_PTR
->aux
= NULL
;
805 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
809 /* Delete any insns that copy a register to itself. */
812 delete_noop_moves (f
)
813 rtx f ATTRIBUTE_UNUSED
;
821 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
823 next
= NEXT_INSN (insn
);
824 if (INSN_P (insn
) && noop_move_p (insn
))
828 /* If we're about to remove the first insn of a libcall
829 then move the libcall note to the next real insn and
830 update the retval note. */
831 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
832 && XEXP (note
, 0) != insn
)
834 rtx new_libcall_insn
= next_real_insn (insn
);
835 rtx retval_note
= find_reg_note (XEXP (note
, 0),
836 REG_RETVAL
, NULL_RTX
);
837 REG_NOTES (new_libcall_insn
)
838 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
839 REG_NOTES (new_libcall_insn
));
840 XEXP (retval_note
, 0) = new_libcall_insn
;
843 delete_insn_and_edges (insn
);
848 if (nnoops
&& rtl_dump_file
)
849 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
853 /* Delete any jump tables never referenced. We can't delete them at the
854 time of removing tablejump insn as they are referenced by the preceding
855 insns computing the destination, so we delay deleting and garbagecollect
856 them once life information is computed. */
858 delete_dead_jumptables ()
861 for (insn
= get_insns (); insn
; insn
= next
)
863 next
= NEXT_INSN (insn
);
864 if (GET_CODE (insn
) == CODE_LABEL
865 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
866 && GET_CODE (next
) == JUMP_INSN
867 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
868 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
871 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
872 delete_insn (NEXT_INSN (insn
));
874 next
= NEXT_INSN (next
);
879 /* Determine if the stack pointer is constant over the life of the function.
880 Only useful before prologues have been emitted. */
883 notice_stack_pointer_modification_1 (x
, pat
, data
)
885 rtx pat ATTRIBUTE_UNUSED
;
886 void *data ATTRIBUTE_UNUSED
;
888 if (x
== stack_pointer_rtx
889 /* The stack pointer is only modified indirectly as the result
890 of a push until later in flow. See the comments in rtl.texi
891 regarding Embedded Side-Effects on Addresses. */
892 || (GET_CODE (x
) == MEM
893 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
894 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
895 current_function_sp_is_unchanging
= 0;
899 notice_stack_pointer_modification (f
)
904 /* Assume that the stack pointer is unchanging if alloca hasn't
906 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
907 if (! current_function_sp_is_unchanging
)
910 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
914 /* Check if insn modifies the stack pointer. */
915 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
917 if (! current_function_sp_is_unchanging
)
923 /* Mark a register in SET. Hard registers in large modes get all
924 of their component registers set as well. */
931 regset set
= (regset
) xset
;
932 int regno
= REGNO (reg
);
934 if (GET_MODE (reg
) == BLKmode
)
937 SET_REGNO_REG_SET (set
, regno
);
938 if (regno
< FIRST_PSEUDO_REGISTER
)
940 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
942 SET_REGNO_REG_SET (set
, regno
+ n
);
946 /* Mark those regs which are needed at the end of the function as live
947 at the end of the last basic block. */
950 mark_regs_live_at_end (set
)
955 /* If exiting needs the right stack value, consider the stack pointer
956 live at the end of the function. */
957 if ((HAVE_epilogue
&& reload_completed
)
958 || ! EXIT_IGNORE_STACK
959 || (! FRAME_POINTER_REQUIRED
960 && ! current_function_calls_alloca
961 && flag_omit_frame_pointer
)
962 || current_function_sp_is_unchanging
)
964 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
967 /* Mark the frame pointer if needed at the end of the function. If
968 we end up eliminating it, it will be removed from the live list
969 of each basic block by reload. */
971 if (! reload_completed
|| frame_pointer_needed
)
973 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
974 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
975 /* If they are different, also mark the hard frame pointer as live. */
976 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
977 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
981 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
982 /* Many architectures have a GP register even without flag_pic.
983 Assume the pic register is not in use, or will be handled by
984 other means, if it is not fixed. */
985 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
986 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
987 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
990 /* Mark all global registers, and all registers used by the epilogue
991 as being live at the end of the function since they may be
992 referenced by our caller. */
993 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
994 if (global_regs
[i
] || EPILOGUE_USES (i
))
995 SET_REGNO_REG_SET (set
, i
);
997 if (HAVE_epilogue
&& reload_completed
)
999 /* Mark all call-saved registers that we actually used. */
1000 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1001 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1002 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1003 SET_REGNO_REG_SET (set
, i
);
1006 #ifdef EH_RETURN_DATA_REGNO
1007 /* Mark the registers that will contain data for the handler. */
1008 if (reload_completed
&& current_function_calls_eh_return
)
1011 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1012 if (regno
== INVALID_REGNUM
)
1014 SET_REGNO_REG_SET (set
, regno
);
1017 #ifdef EH_RETURN_STACKADJ_RTX
1018 if ((! HAVE_epilogue
|| ! reload_completed
)
1019 && current_function_calls_eh_return
)
1021 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1022 if (tmp
&& REG_P (tmp
))
1023 mark_reg (tmp
, set
);
1026 #ifdef EH_RETURN_HANDLER_RTX
1027 if ((! HAVE_epilogue
|| ! reload_completed
)
1028 && current_function_calls_eh_return
)
1030 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1031 if (tmp
&& REG_P (tmp
))
1032 mark_reg (tmp
, set
);
1036 /* Mark function return value. */
1037 diddle_return_value (mark_reg
, set
);
1040 /* Callback function for for_each_successor_phi. DATA is a regset.
1041 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1042 INSN, in the regset. */
1045 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1046 rtx insn ATTRIBUTE_UNUSED
;
1047 int dest_regno ATTRIBUTE_UNUSED
;
1051 regset live
= (regset
) data
;
1052 SET_REGNO_REG_SET (live
, src_regno
);
1056 /* Propagate global life info around the graph of basic blocks. Begin
1057 considering blocks with their corresponding bit set in BLOCKS_IN.
1058 If BLOCKS_IN is null, consider it the universal set.
1060 BLOCKS_OUT is set for every block that was changed. */
1063 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1064 sbitmap blocks_in
, blocks_out
;
1067 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1068 regset tmp
, new_live_at_end
, call_used
;
1069 regset_head tmp_head
, call_used_head
;
1070 regset_head new_live_at_end_head
;
1073 /* Some passes used to forget clear aux field of basic block causing
1074 sick behaviour here. */
1075 #ifdef ENABLE_CHECKING
1076 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1081 tmp
= INITIALIZE_REG_SET (tmp_head
);
1082 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1083 call_used
= INITIALIZE_REG_SET (call_used_head
);
1085 /* Inconveniently, this is only readily available in hard reg set form. */
1086 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1087 if (call_used_regs
[i
])
1088 SET_REGNO_REG_SET (call_used
, i
);
1090 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1091 because the `head == tail' style test for an empty queue doesn't
1092 work with a full queue. */
1093 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1095 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1097 /* Queue the blocks set in the initial mask. Do this in reverse block
1098 number order so that we are more likely for the first round to do
1099 useful work. We use AUX non-null to flag that the block is queued. */
1103 if (TEST_BIT (blocks_in
, bb
->index
))
1111 for (i
= 0; i
< n_basic_blocks
; ++i
)
1113 basic_block bb
= BASIC_BLOCK (i
);
1119 /* We clean aux when we remove the initially-enqueued bbs, but we
1120 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1122 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1125 sbitmap_zero (blocks_out
);
1127 /* We work through the queue until there are no more blocks. What
1128 is live at the end of this block is precisely the union of what
1129 is live at the beginning of all its successors. So, we set its
1130 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1131 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1132 this block by walking through the instructions in this block in
1133 reverse order and updating as we go. If that changed
1134 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1135 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1137 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1138 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1139 must either be live at the end of the block, or used within the
1140 block. In the latter case, it will certainly never disappear
1141 from GLOBAL_LIVE_AT_START. In the former case, the register
1142 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1143 for one of the successor blocks. By induction, that cannot
1145 while (qhead
!= qtail
)
1147 int rescan
, changed
;
1156 /* Begin by propagating live_at_start from the successor blocks. */
1157 CLEAR_REG_SET (new_live_at_end
);
1160 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1162 basic_block sb
= e
->dest
;
1164 /* Call-clobbered registers die across exception and
1166 /* ??? Abnormal call edges ignored for the moment, as this gets
1167 confused by sibling call edges, which crashes reg-stack. */
1168 if (e
->flags
& EDGE_EH
)
1170 bitmap_operation (tmp
, sb
->global_live_at_start
,
1171 call_used
, BITMAP_AND_COMPL
);
1172 IOR_REG_SET (new_live_at_end
, tmp
);
1175 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1177 /* If a target saves one register in another (instead of on
1178 the stack) the save register will need to be live for EH. */
1179 if (e
->flags
& EDGE_EH
)
1180 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1182 SET_REGNO_REG_SET (new_live_at_end
, i
);
1186 /* This might be a noreturn function that throws. And
1187 even if it isn't, getting the unwind info right helps
1189 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1191 SET_REGNO_REG_SET (new_live_at_end
, i
);
1194 /* The all-important stack pointer must always be live. */
1195 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1197 /* Before reload, there are a few registers that must be forced
1198 live everywhere -- which might not already be the case for
1199 blocks within infinite loops. */
1200 if (! reload_completed
)
1202 /* Any reference to any pseudo before reload is a potential
1203 reference of the frame pointer. */
1204 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1206 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1207 /* Pseudos with argument area equivalences may require
1208 reloading via the argument pointer. */
1209 if (fixed_regs
[ARG_POINTER_REGNUM
])
1210 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1213 /* Any constant, or pseudo with constant equivalences, may
1214 require reloading from memory using the pic register. */
1215 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1216 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1217 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1220 /* Regs used in phi nodes are not included in
1221 global_live_at_start, since they are live only along a
1222 particular edge. Set those regs that are live because of a
1223 phi node alternative corresponding to this particular block. */
1225 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1228 if (bb
== ENTRY_BLOCK_PTR
)
1230 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1234 /* On our first pass through this block, we'll go ahead and continue.
1235 Recognize first pass by local_set NULL. On subsequent passes, we
1236 get to skip out early if live_at_end wouldn't have changed. */
1238 if (bb
->local_set
== NULL
)
1240 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1241 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1246 /* If any bits were removed from live_at_end, we'll have to
1247 rescan the block. This wouldn't be necessary if we had
1248 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1249 local_live is really dependent on live_at_end. */
1250 CLEAR_REG_SET (tmp
);
1251 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1252 new_live_at_end
, BITMAP_AND_COMPL
);
1256 /* If any of the registers in the new live_at_end set are
1257 conditionally set in this basic block, we must rescan.
1258 This is because conditional lifetimes at the end of the
1259 block do not just take the live_at_end set into account,
1260 but also the liveness at the start of each successor
1261 block. We can miss changes in those sets if we only
1262 compare the new live_at_end against the previous one. */
1263 CLEAR_REG_SET (tmp
);
1264 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1265 bb
->cond_local_set
, BITMAP_AND
);
1270 /* Find the set of changed bits. Take this opportunity
1271 to notice that this set is empty and early out. */
1272 CLEAR_REG_SET (tmp
);
1273 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1274 new_live_at_end
, BITMAP_XOR
);
1278 /* If any of the changed bits overlap with local_set,
1279 we'll have to rescan the block. Detect overlap by
1280 the AND with ~local_set turning off bits. */
1281 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1286 /* Let our caller know that BB changed enough to require its
1287 death notes updated. */
1289 SET_BIT (blocks_out
, bb
->index
);
1293 /* Add to live_at_start the set of all registers in
1294 new_live_at_end that aren't in the old live_at_end. */
1296 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1298 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1300 changed
= bitmap_operation (bb
->global_live_at_start
,
1301 bb
->global_live_at_start
,
1308 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1310 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1311 into live_at_start. */
1312 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1313 bb
->cond_local_set
, flags
);
1315 /* If live_at start didn't change, no need to go farther. */
1316 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1319 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1322 /* Queue all predecessors of BB so that we may re-examine
1323 their live_at_end. */
1324 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1326 basic_block pb
= e
->src
;
1327 if (pb
->aux
== NULL
)
1338 FREE_REG_SET (new_live_at_end
);
1339 FREE_REG_SET (call_used
);
1343 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1345 basic_block bb
= BASIC_BLOCK (i
);
1346 FREE_REG_SET (bb
->local_set
);
1347 FREE_REG_SET (bb
->cond_local_set
);
1354 FREE_REG_SET (bb
->local_set
);
1355 FREE_REG_SET (bb
->cond_local_set
);
1363 /* This structure is used to pass parameters to an from the
1364 the function find_regno_partial(). It is used to pass in the
1365 register number we are looking, as well as to return any rtx
1369 unsigned regno_to_find
;
1371 } find_regno_partial_param
;
1374 /* Find the rtx for the reg numbers specified in 'data' if it is
1375 part of an expression which only uses part of the register. Return
1376 it in the structure passed in. */
1378 find_regno_partial (ptr
, data
)
1382 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1383 unsigned reg
= param
->regno_to_find
;
1384 param
->retval
= NULL_RTX
;
1386 if (*ptr
== NULL_RTX
)
1389 switch (GET_CODE (*ptr
))
1393 case STRICT_LOW_PART
:
1394 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1396 param
->retval
= XEXP (*ptr
, 0);
1402 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1403 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1405 param
->retval
= SUBREG_REG (*ptr
);
1417 /* Process all immediate successors of the entry block looking for pseudo
1418 registers which are live on entry. Find all of those whose first
1419 instance is a partial register reference of some kind, and initialize
1420 them to 0 after the entry block. This will prevent bit sets within
1421 registers whose value is unknown, and may contain some kind of sticky
1422 bits we don't want. */
1425 initialize_uninitialized_subregs ()
1429 int reg
, did_something
= 0;
1430 find_regno_partial_param param
;
1432 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1434 basic_block bb
= e
->dest
;
1435 regset map
= bb
->global_live_at_start
;
1436 EXECUTE_IF_SET_IN_REG_SET (map
,
1437 FIRST_PSEUDO_REGISTER
, reg
,
1439 int uid
= REGNO_FIRST_UID (reg
);
1442 /* Find an insn which mentions the register we are looking for.
1443 Its preferable to have an instance of the register's rtl since
1444 there may be various flags set which we need to duplicate.
1445 If we can't find it, its probably an automatic whose initial
1446 value doesn't matter, or hopefully something we don't care about. */
1447 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1451 /* Found the insn, now get the REG rtx, if we can. */
1452 param
.regno_to_find
= reg
;
1453 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1454 if (param
.retval
!= NULL_RTX
)
1456 insn
= gen_move_insn (param
.retval
,
1457 CONST0_RTX (GET_MODE (param
.retval
)));
1458 insert_insn_on_edge (insn
, e
);
1466 commit_edge_insertions ();
1467 return did_something
;
1471 /* Subroutines of life analysis. */
1473 /* Allocate the permanent data structures that represent the results
1474 of life analysis. Not static since used also for stupid life analysis. */
1477 allocate_bb_life_data ()
1481 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1483 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1484 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1487 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1491 allocate_reg_life_data ()
1495 max_regno
= max_reg_num ();
1497 /* Recalculate the register space, in case it has grown. Old style
1498 vector oriented regsets would set regset_{size,bytes} here also. */
1499 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1501 /* Reset all the data we'll collect in propagate_block and its
1503 for (i
= 0; i
< max_regno
; i
++)
1507 REG_N_DEATHS (i
) = 0;
1508 REG_N_CALLS_CROSSED (i
) = 0;
1509 REG_LIVE_LENGTH (i
) = 0;
1510 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1514 /* Delete dead instructions for propagate_block. */
1517 propagate_block_delete_insn (insn
)
1520 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1522 /* If the insn referred to a label, and that label was attached to
1523 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1524 pretty much mandatory to delete it, because the ADDR_VEC may be
1525 referencing labels that no longer exist.
1527 INSN may reference a deleted label, particularly when a jump
1528 table has been optimized into a direct jump. There's no
1529 real good way to fix up the reference to the deleted label
1530 when the label is deleted, so we just allow it here. */
1532 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1534 rtx label
= XEXP (inote
, 0);
1537 /* The label may be forced if it has been put in the constant
1538 pool. If that is the only use we must discard the table
1539 jump following it, but not the label itself. */
1540 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1541 && (next
= next_nonnote_insn (label
)) != NULL
1542 && GET_CODE (next
) == JUMP_INSN
1543 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1544 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1546 rtx pat
= PATTERN (next
);
1547 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1548 int len
= XVECLEN (pat
, diff_vec_p
);
1551 for (i
= 0; i
< len
; i
++)
1552 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1554 delete_insn_and_edges (next
);
1559 delete_insn_and_edges (insn
);
1563 /* Delete dead libcalls for propagate_block. Return the insn
1564 before the libcall. */
1567 propagate_block_delete_libcall ( insn
, note
)
1570 rtx first
= XEXP (note
, 0);
1571 rtx before
= PREV_INSN (first
);
1573 delete_insn_chain_and_edges (first
, insn
);
1578 /* Update the life-status of regs for one insn. Return the previous insn. */
1581 propagate_one_insn (pbi
, insn
)
1582 struct propagate_block_info
*pbi
;
1585 rtx prev
= PREV_INSN (insn
);
1586 int flags
= pbi
->flags
;
1587 int insn_is_dead
= 0;
1588 int libcall_is_dead
= 0;
1592 if (! INSN_P (insn
))
1595 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1596 if (flags
& PROP_SCAN_DEAD_CODE
)
1598 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1599 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1600 && libcall_dead_p (pbi
, note
, insn
));
1603 /* If an instruction consists of just dead store(s) on final pass,
1605 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1607 /* If we're trying to delete a prologue or epilogue instruction
1608 that isn't flagged as possibly being dead, something is wrong.
1609 But if we are keeping the stack pointer depressed, we might well
1610 be deleting insns that are used to compute the amount to update
1611 it by, so they are fine. */
1612 if (reload_completed
1613 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1614 && (TYPE_RETURNS_STACK_DEPRESSED
1615 (TREE_TYPE (current_function_decl
))))
1616 && (((HAVE_epilogue
|| HAVE_prologue
)
1617 && prologue_epilogue_contains (insn
))
1618 || (HAVE_sibcall_epilogue
1619 && sibcall_epilogue_contains (insn
)))
1620 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1621 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1623 /* Record sets. Do this even for dead instructions, since they
1624 would have killed the values if they hadn't been deleted. */
1625 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1627 /* CC0 is now known to be dead. Either this insn used it,
1628 in which case it doesn't anymore, or clobbered it,
1629 so the next insn can't use it. */
1632 if (libcall_is_dead
)
1633 prev
= propagate_block_delete_libcall ( insn
, note
);
1635 propagate_block_delete_insn (insn
);
1640 /* See if this is an increment or decrement that can be merged into
1641 a following memory address. */
1644 rtx x
= single_set (insn
);
1646 /* Does this instruction increment or decrement a register? */
1647 if ((flags
& PROP_AUTOINC
)
1649 && GET_CODE (SET_DEST (x
)) == REG
1650 && (GET_CODE (SET_SRC (x
)) == PLUS
1651 || GET_CODE (SET_SRC (x
)) == MINUS
)
1652 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1653 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1654 /* Ok, look for a following memory ref we can combine with.
1655 If one is found, change the memory ref to a PRE_INC
1656 or PRE_DEC, cancel this insn, and return 1.
1657 Return 0 if nothing has been done. */
1658 && try_pre_increment_1 (pbi
, insn
))
1661 #endif /* AUTO_INC_DEC */
1663 CLEAR_REG_SET (pbi
->new_set
);
1665 /* If this is not the final pass, and this insn is copying the value of
1666 a library call and it's dead, don't scan the insns that perform the
1667 library call, so that the call's arguments are not marked live. */
1668 if (libcall_is_dead
)
1670 /* Record the death of the dest reg. */
1671 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1673 insn
= XEXP (note
, 0);
1674 return PREV_INSN (insn
);
1676 else if (GET_CODE (PATTERN (insn
)) == SET
1677 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1678 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1679 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1680 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1681 /* We have an insn to pop a constant amount off the stack.
1682 (Such insns use PLUS regardless of the direction of the stack,
1683 and any insn to adjust the stack by a constant is always a pop.)
1684 These insns, if not dead stores, have no effect on life, though
1685 they do have an effect on the memory stores we are tracking. */
1686 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1690 /* Any regs live at the time of a call instruction must not go
1691 in a register clobbered by calls. Find all regs now live and
1692 record this for them. */
1694 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1695 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1696 { REG_N_CALLS_CROSSED (i
)++; });
1698 /* Record sets. Do this even for dead instructions, since they
1699 would have killed the values if they hadn't been deleted. */
1700 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1702 if (GET_CODE (insn
) == CALL_INSN
)
1708 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1709 cond
= COND_EXEC_TEST (PATTERN (insn
));
1711 /* Non-constant calls clobber memory, constant calls do not
1712 clobber memory, though they may clobber outgoing arguments
1714 if (! CONST_OR_PURE_CALL_P (insn
))
1716 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1717 pbi
->mem_set_list_len
= 0;
1720 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1722 /* There may be extra registers to be clobbered. */
1723 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1725 note
= XEXP (note
, 1))
1726 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1727 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1728 cond
, insn
, pbi
->flags
);
1730 /* Calls change all call-used and global registers. */
1731 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1732 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1734 /* We do not want REG_UNUSED notes for these registers. */
1735 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1737 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1741 /* If an insn doesn't use CC0, it becomes dead since we assume
1742 that every insn clobbers it. So show it dead here;
1743 mark_used_regs will set it live if it is referenced. */
1748 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1749 if ((flags
& PROP_EQUAL_NOTES
)
1750 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1751 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1752 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1754 /* Sometimes we may have inserted something before INSN (such as a move)
1755 when we make an auto-inc. So ensure we will scan those insns. */
1757 prev
= PREV_INSN (insn
);
1760 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1766 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1767 cond
= COND_EXEC_TEST (PATTERN (insn
));
1769 /* Calls use their arguments. */
1770 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1772 note
= XEXP (note
, 1))
1773 if (GET_CODE (XEXP (note
, 0)) == USE
)
1774 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1777 /* The stack ptr is used (honorarily) by a CALL insn. */
1778 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1780 /* Calls may also reference any of the global registers,
1781 so they are made live. */
1782 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1784 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1789 /* On final pass, update counts of how many insns in which each reg
1791 if (flags
& PROP_REG_INFO
)
1792 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1793 { REG_LIVE_LENGTH (i
)++; });
1798 /* Initialize a propagate_block_info struct for public consumption.
1799 Note that the structure itself is opaque to this file, but that
1800 the user can use the regsets provided here. */
1802 struct propagate_block_info
*
1803 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1805 regset live
, local_set
, cond_local_set
;
1808 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1811 pbi
->reg_live
= live
;
1812 pbi
->mem_set_list
= NULL_RTX
;
1813 pbi
->mem_set_list_len
= 0;
1814 pbi
->local_set
= local_set
;
1815 pbi
->cond_local_set
= cond_local_set
;
1819 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1820 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1822 pbi
->reg_next_use
= NULL
;
1824 pbi
->new_set
= BITMAP_XMALLOC ();
1826 #ifdef HAVE_conditional_execution
1827 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1828 free_reg_cond_life_info
);
1829 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1831 /* If this block ends in a conditional branch, for each register live
1832 from one side of the branch and not the other, record the register
1833 as conditionally dead. */
1834 if (GET_CODE (bb
->end
) == JUMP_INSN
1835 && any_condjump_p (bb
->end
))
1837 regset_head diff_head
;
1838 regset diff
= INITIALIZE_REG_SET (diff_head
);
1839 basic_block bb_true
, bb_false
;
1840 rtx cond_true
, cond_false
, set_src
;
1843 /* Identify the successor blocks. */
1844 bb_true
= bb
->succ
->dest
;
1845 if (bb
->succ
->succ_next
!= NULL
)
1847 bb_false
= bb
->succ
->succ_next
->dest
;
1849 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1851 basic_block t
= bb_false
;
1855 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1860 /* This can happen with a conditional jump to the next insn. */
1861 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1864 /* Simplest way to do nothing. */
1868 /* Extract the condition from the branch. */
1869 set_src
= SET_SRC (pc_set (bb
->end
));
1870 cond_true
= XEXP (set_src
, 0);
1871 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1872 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1873 XEXP (cond_true
, 1));
1874 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1877 cond_false
= cond_true
;
1881 /* Compute which register lead different lives in the successors. */
1882 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1883 bb_false
->global_live_at_start
, BITMAP_XOR
))
1885 rtx reg
= XEXP (cond_true
, 0);
1887 if (GET_CODE (reg
) == SUBREG
)
1888 reg
= SUBREG_REG (reg
);
1890 if (GET_CODE (reg
) != REG
)
1893 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1895 /* For each such register, mark it conditionally dead. */
1896 EXECUTE_IF_SET_IN_REG_SET
1899 struct reg_cond_life_info
*rcli
;
1902 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1904 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1908 rcli
->condition
= cond
;
1909 rcli
->stores
= const0_rtx
;
1910 rcli
->orig_condition
= cond
;
1912 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1913 (splay_tree_value
) rcli
);
1917 FREE_REG_SET (diff
);
1921 /* If this block has no successors, any stores to the frame that aren't
1922 used later in the block are dead. So make a pass over the block
1923 recording any such that are made and show them dead at the end. We do
1924 a very conservative and simple job here. */
1926 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1927 && (TYPE_RETURNS_STACK_DEPRESSED
1928 (TREE_TYPE (current_function_decl
))))
1929 && (flags
& PROP_SCAN_DEAD_STORES
)
1930 && (bb
->succ
== NULL
1931 || (bb
->succ
->succ_next
== NULL
1932 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1933 && ! current_function_calls_eh_return
)))
1936 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1937 if (GET_CODE (insn
) == INSN
1938 && (set
= single_set (insn
))
1939 && GET_CODE (SET_DEST (set
)) == MEM
)
1941 rtx mem
= SET_DEST (set
);
1942 rtx canon_mem
= canon_rtx (mem
);
1944 /* This optimization is performed by faking a store to the
1945 memory at the end of the block. This doesn't work for
1946 unchanging memories because multiple stores to unchanging
1947 memory is illegal and alias analysis doesn't consider it. */
1948 if (RTX_UNCHANGING_P (canon_mem
))
1951 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1952 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1953 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1954 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1955 add_to_mem_set_list (pbi
, canon_mem
);
1962 /* Release a propagate_block_info struct. */
1965 free_propagate_block_info (pbi
)
1966 struct propagate_block_info
*pbi
;
1968 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1970 BITMAP_XFREE (pbi
->new_set
);
1972 #ifdef HAVE_conditional_execution
1973 splay_tree_delete (pbi
->reg_cond_dead
);
1974 BITMAP_XFREE (pbi
->reg_cond_reg
);
1977 if (pbi
->reg_next_use
)
1978 free (pbi
->reg_next_use
);
1983 /* Compute the registers live at the beginning of a basic block BB from
1984 those live at the end.
1986 When called, REG_LIVE contains those live at the end. On return, it
1987 contains those live at the beginning.
1989 LOCAL_SET, if non-null, will be set with all registers killed
1990 unconditionally by this basic block.
1991 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1992 killed conditionally by this basic block. If there is any unconditional
1993 set of a register, then the corresponding bit will be set in LOCAL_SET
1994 and cleared in COND_LOCAL_SET.
1995 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1996 case, the resulting set will be equal to the union of the two sets that
1997 would otherwise be computed.
1999 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2002 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2006 regset cond_local_set
;
2009 struct propagate_block_info
*pbi
;
2013 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2015 if (flags
& PROP_REG_INFO
)
2019 /* Process the regs live at the end of the block.
2020 Mark them as not local to any one basic block. */
2021 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2022 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2025 /* Scan the block an insn at a time from end to beginning. */
2028 for (insn
= bb
->end
;; insn
= prev
)
2030 /* If this is a call to `setjmp' et al, warn if any
2031 non-volatile datum is live. */
2032 if ((flags
& PROP_REG_INFO
)
2033 && GET_CODE (insn
) == CALL_INSN
2034 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2035 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2037 prev
= propagate_one_insn (pbi
, insn
);
2038 changed
|= NEXT_INSN (prev
) != insn
;
2040 if (insn
== bb
->head
)
2044 free_propagate_block_info (pbi
);
2049 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2050 (SET expressions whose destinations are registers dead after the insn).
2051 NEEDED is the regset that says which regs are alive after the insn.
2053 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2055 If X is the entire body of an insn, NOTES contains the reg notes
2056 pertaining to the insn. */
2059 insn_dead_p (pbi
, x
, call_ok
, notes
)
2060 struct propagate_block_info
*pbi
;
2063 rtx notes ATTRIBUTE_UNUSED
;
2065 enum rtx_code code
= GET_CODE (x
);
2068 /* As flow is invoked after combine, we must take existing AUTO_INC
2069 expressions into account. */
2070 for (; notes
; notes
= XEXP (notes
, 1))
2072 if (REG_NOTE_KIND (notes
) == REG_INC
)
2074 int regno
= REGNO (XEXP (notes
, 0));
2076 /* Don't delete insns to set global regs. */
2077 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2078 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2084 /* If setting something that's a reg or part of one,
2085 see if that register's altered value will be live. */
2089 rtx r
= SET_DEST (x
);
2092 if (GET_CODE (r
) == CC0
)
2093 return ! pbi
->cc0_live
;
2096 /* A SET that is a subroutine call cannot be dead. */
2097 if (GET_CODE (SET_SRC (x
)) == CALL
)
2103 /* Don't eliminate loads from volatile memory or volatile asms. */
2104 else if (volatile_refs_p (SET_SRC (x
)))
2107 if (GET_CODE (r
) == MEM
)
2111 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2114 canon_r
= canon_rtx (r
);
2116 /* Walk the set of memory locations we are currently tracking
2117 and see if one is an identical match to this memory location.
2118 If so, this memory write is dead (remember, we're walking
2119 backwards from the end of the block to the start). Since
2120 rtx_equal_p does not check the alias set or flags, we also
2121 must have the potential for them to conflict (anti_dependence). */
2122 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2123 if (anti_dependence (r
, XEXP (temp
, 0)))
2125 rtx mem
= XEXP (temp
, 0);
2127 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2128 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2129 <= GET_MODE_SIZE (GET_MODE (mem
))))
2133 /* Check if memory reference matches an auto increment. Only
2134 post increment/decrement or modify are valid. */
2135 if (GET_MODE (mem
) == GET_MODE (r
)
2136 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2137 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2138 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2139 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2140 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2147 while (GET_CODE (r
) == SUBREG
2148 || GET_CODE (r
) == STRICT_LOW_PART
2149 || GET_CODE (r
) == ZERO_EXTRACT
)
2152 if (GET_CODE (r
) == REG
)
2154 int regno
= REGNO (r
);
2157 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2160 /* If this is a hard register, verify that subsequent
2161 words are not needed. */
2162 if (regno
< FIRST_PSEUDO_REGISTER
)
2164 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2167 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2171 /* Don't delete insns to set global regs. */
2172 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2175 /* Make sure insns to set the stack pointer aren't deleted. */
2176 if (regno
== STACK_POINTER_REGNUM
)
2179 /* ??? These bits might be redundant with the force live bits
2180 in calculate_global_regs_live. We would delete from
2181 sequential sets; whether this actually affects real code
2182 for anything but the stack pointer I don't know. */
2183 /* Make sure insns to set the frame pointer aren't deleted. */
2184 if (regno
== FRAME_POINTER_REGNUM
2185 && (! reload_completed
|| frame_pointer_needed
))
2187 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2188 if (regno
== HARD_FRAME_POINTER_REGNUM
2189 && (! reload_completed
|| frame_pointer_needed
))
2193 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2194 /* Make sure insns to set arg pointer are never deleted
2195 (if the arg pointer isn't fixed, there will be a USE
2196 for it, so we can treat it normally). */
2197 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2201 /* Otherwise, the set is dead. */
2207 /* If performing several activities, insn is dead if each activity
2208 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2209 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2211 else if (code
== PARALLEL
)
2213 int i
= XVECLEN (x
, 0);
2215 for (i
--; i
>= 0; i
--)
2216 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2217 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2218 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2224 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2225 is not necessarily true for hard registers. */
2226 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2227 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2228 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2231 /* We do not check other CLOBBER or USE here. An insn consisting of just
2232 a CLOBBER or just a USE should not be deleted. */
2236 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2237 return 1 if the entire library call is dead.
2238 This is true if INSN copies a register (hard or pseudo)
2239 and if the hard return reg of the call insn is dead.
2240 (The caller should have tested the destination of the SET inside
2241 INSN already for death.)
2243 If this insn doesn't just copy a register, then we don't
2244 have an ordinary libcall. In that case, cse could not have
2245 managed to substitute the source for the dest later on,
2246 so we can assume the libcall is dead.
2248 PBI is the block info giving pseudoregs live before this insn.
2249 NOTE is the REG_RETVAL note of the insn. */
2252 libcall_dead_p (pbi
, note
, insn
)
2253 struct propagate_block_info
*pbi
;
2257 rtx x
= single_set (insn
);
2261 rtx r
= SET_SRC (x
);
2263 if (GET_CODE (r
) == REG
)
2265 rtx call
= XEXP (note
, 0);
2269 /* Find the call insn. */
2270 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2271 call
= NEXT_INSN (call
);
2273 /* If there is none, do nothing special,
2274 since ordinary death handling can understand these insns. */
2278 /* See if the hard reg holding the value is dead.
2279 If this is a PARALLEL, find the call within it. */
2280 call_pat
= PATTERN (call
);
2281 if (GET_CODE (call_pat
) == PARALLEL
)
2283 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2284 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2285 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2288 /* This may be a library call that is returning a value
2289 via invisible pointer. Do nothing special, since
2290 ordinary death handling can understand these insns. */
2294 call_pat
= XVECEXP (call_pat
, 0, i
);
2297 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2303 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2304 live at function entry. Don't count global register variables, variables
2305 in registers that can be used for function arg passing, or variables in
2306 fixed hard registers. */
2309 regno_uninitialized (regno
)
2312 if (n_basic_blocks
== 0
2313 || (regno
< FIRST_PSEUDO_REGISTER
2314 && (global_regs
[regno
]
2315 || fixed_regs
[regno
]
2316 || FUNCTION_ARG_REGNO_P (regno
))))
2319 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2322 /* 1 if register REGNO was alive at a place where `setjmp' was called
2323 and was set more than once or is an argument.
2324 Such regs may be clobbered by `longjmp'. */
2327 regno_clobbered_at_setjmp (regno
)
2330 if (n_basic_blocks
== 0)
2333 return ((REG_N_SETS (regno
) > 1
2334 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2335 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2338 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2339 maximal list size; look for overlaps in mode and select the largest. */
2341 add_to_mem_set_list (pbi
, mem
)
2342 struct propagate_block_info
*pbi
;
2347 /* We don't know how large a BLKmode store is, so we must not
2348 take them into consideration. */
2349 if (GET_MODE (mem
) == BLKmode
)
2352 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2354 rtx e
= XEXP (i
, 0);
2355 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2357 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2360 /* If we must store a copy of the mem, we can just modify
2361 the mode of the stored copy. */
2362 if (pbi
->flags
& PROP_AUTOINC
)
2363 PUT_MODE (e
, GET_MODE (mem
));
2372 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2375 /* Store a copy of mem, otherwise the address may be
2376 scrogged by find_auto_inc. */
2377 if (pbi
->flags
& PROP_AUTOINC
)
2378 mem
= shallow_copy_rtx (mem
);
2380 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2381 pbi
->mem_set_list_len
++;
2385 /* INSN references memory, possibly using autoincrement addressing modes.
2386 Find any entries on the mem_set_list that need to be invalidated due
2387 to an address change. */
2390 invalidate_mems_from_autoinc (px
, data
)
2395 struct propagate_block_info
*pbi
= data
;
2397 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2399 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2406 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2409 invalidate_mems_from_set (pbi
, exp
)
2410 struct propagate_block_info
*pbi
;
2413 rtx temp
= pbi
->mem_set_list
;
2414 rtx prev
= NULL_RTX
;
2419 next
= XEXP (temp
, 1);
2420 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2422 /* Splice this entry out of the list. */
2424 XEXP (prev
, 1) = next
;
2426 pbi
->mem_set_list
= next
;
2427 free_EXPR_LIST_node (temp
);
2428 pbi
->mem_set_list_len
--;
2436 /* Process the registers that are set within X. Their bits are set to
2437 1 in the regset DEAD, because they are dead prior to this insn.
2439 If INSN is nonzero, it is the insn being processed.
2441 FLAGS is the set of operations to perform. */
2444 mark_set_regs (pbi
, x
, insn
)
2445 struct propagate_block_info
*pbi
;
2448 rtx cond
= NULL_RTX
;
2453 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2455 if (REG_NOTE_KIND (link
) == REG_INC
)
2456 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2457 (GET_CODE (x
) == COND_EXEC
2458 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2462 switch (code
= GET_CODE (x
))
2466 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2470 cond
= COND_EXEC_TEST (x
);
2471 x
= COND_EXEC_CODE (x
);
2478 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2480 rtx sub
= XVECEXP (x
, 0, i
);
2481 switch (code
= GET_CODE (sub
))
2484 if (cond
!= NULL_RTX
)
2487 cond
= COND_EXEC_TEST (sub
);
2488 sub
= COND_EXEC_CODE (sub
);
2489 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2495 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2510 /* Process a single set, which appears in INSN. REG (which may not
2511 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2512 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2513 If the set is conditional (because it appear in a COND_EXEC), COND
2514 will be the condition. */
2517 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2518 struct propagate_block_info
*pbi
;
2520 rtx reg
, cond
, insn
;
2523 int regno_first
= -1, regno_last
= -1;
2524 unsigned long not_dead
= 0;
2527 /* Modifying just one hardware register of a multi-reg value or just a
2528 byte field of a register does not mean the value from before this insn
2529 is now dead. Of course, if it was dead after it's unused now. */
2531 switch (GET_CODE (reg
))
2534 /* Some targets place small structures in registers for return values of
2535 functions. We have to detect this case specially here to get correct
2536 flow information. */
2537 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2538 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2539 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2545 case STRICT_LOW_PART
:
2546 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2548 reg
= XEXP (reg
, 0);
2549 while (GET_CODE (reg
) == SUBREG
2550 || GET_CODE (reg
) == ZERO_EXTRACT
2551 || GET_CODE (reg
) == SIGN_EXTRACT
2552 || GET_CODE (reg
) == STRICT_LOW_PART
);
2553 if (GET_CODE (reg
) == MEM
)
2555 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2559 regno_last
= regno_first
= REGNO (reg
);
2560 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2561 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2565 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2567 enum machine_mode outer_mode
= GET_MODE (reg
);
2568 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2570 /* Identify the range of registers affected. This is moderately
2571 tricky for hard registers. See alter_subreg. */
2573 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2574 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2576 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2579 regno_last
= (regno_first
2580 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2582 /* Since we've just adjusted the register number ranges, make
2583 sure REG matches. Otherwise some_was_live will be clear
2584 when it shouldn't have been, and we'll create incorrect
2585 REG_UNUSED notes. */
2586 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2590 /* If the number of words in the subreg is less than the number
2591 of words in the full register, we have a well-defined partial
2592 set. Otherwise the high bits are undefined.
2594 This is only really applicable to pseudos, since we just took
2595 care of multi-word hard registers. */
2596 if (((GET_MODE_SIZE (outer_mode
)
2597 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2598 < ((GET_MODE_SIZE (inner_mode
)
2599 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2600 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2603 reg
= SUBREG_REG (reg
);
2607 reg
= SUBREG_REG (reg
);
2614 /* If this set is a MEM, then it kills any aliased writes.
2615 If this set is a REG, then it kills any MEMs which use the reg. */
2616 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2618 if (GET_CODE (reg
) == REG
)
2619 invalidate_mems_from_set (pbi
, reg
);
2621 /* If the memory reference had embedded side effects (autoincrement
2622 address modes. Then we may need to kill some entries on the
2624 if (insn
&& GET_CODE (reg
) == MEM
)
2625 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2627 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2628 /* ??? With more effort we could track conditional memory life. */
2630 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2633 if (GET_CODE (reg
) == REG
2634 && ! (regno_first
== FRAME_POINTER_REGNUM
2635 && (! reload_completed
|| frame_pointer_needed
))
2636 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2637 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2638 && (! reload_completed
|| frame_pointer_needed
))
2640 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2641 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2645 int some_was_live
= 0, some_was_dead
= 0;
2647 for (i
= regno_first
; i
<= regno_last
; ++i
)
2649 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2652 /* Order of the set operation matters here since both
2653 sets may be the same. */
2654 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2655 if (cond
!= NULL_RTX
2656 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2657 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2659 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2661 if (code
!= CLOBBER
)
2662 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2664 some_was_live
|= needed_regno
;
2665 some_was_dead
|= ! needed_regno
;
2668 #ifdef HAVE_conditional_execution
2669 /* Consider conditional death in deciding that the register needs
2671 if (some_was_live
&& ! not_dead
2672 /* The stack pointer is never dead. Well, not strictly true,
2673 but it's very difficult to tell from here. Hopefully
2674 combine_stack_adjustments will fix up the most egregious
2676 && regno_first
!= STACK_POINTER_REGNUM
)
2678 for (i
= regno_first
; i
<= regno_last
; ++i
)
2679 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2680 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2684 /* Additional data to record if this is the final pass. */
2685 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2686 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2689 int blocknum
= pbi
->bb
->index
;
2692 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2694 y
= pbi
->reg_next_use
[regno_first
];
2696 /* The next use is no longer next, since a store intervenes. */
2697 for (i
= regno_first
; i
<= regno_last
; ++i
)
2698 pbi
->reg_next_use
[i
] = 0;
2701 if (flags
& PROP_REG_INFO
)
2703 for (i
= regno_first
; i
<= regno_last
; ++i
)
2705 /* Count (weighted) references, stores, etc. This counts a
2706 register twice if it is modified, but that is correct. */
2707 REG_N_SETS (i
) += 1;
2708 REG_N_REFS (i
) += 1;
2709 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2711 /* The insns where a reg is live are normally counted
2712 elsewhere, but we want the count to include the insn
2713 where the reg is set, and the normal counting mechanism
2714 would not count it. */
2715 REG_LIVE_LENGTH (i
) += 1;
2718 /* If this is a hard reg, record this function uses the reg. */
2719 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2721 for (i
= regno_first
; i
<= regno_last
; i
++)
2722 regs_ever_live
[i
] = 1;
2726 /* Keep track of which basic blocks each reg appears in. */
2727 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2728 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2729 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2730 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2734 if (! some_was_dead
)
2736 if (flags
& PROP_LOG_LINKS
)
2738 /* Make a logical link from the next following insn
2739 that uses this register, back to this insn.
2740 The following insns have already been processed.
2742 We don't build a LOG_LINK for hard registers containing
2743 in ASM_OPERANDs. If these registers get replaced,
2744 we might wind up changing the semantics of the insn,
2745 even if reload can make what appear to be valid
2746 assignments later. */
2747 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2748 && (regno_first
>= FIRST_PSEUDO_REGISTER
2749 || asm_noperands (PATTERN (y
)) < 0))
2750 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2755 else if (! some_was_live
)
2757 if (flags
& PROP_REG_INFO
)
2758 REG_N_DEATHS (regno_first
) += 1;
2760 if (flags
& PROP_DEATH_NOTES
)
2762 /* Note that dead stores have already been deleted
2763 when possible. If we get here, we have found a
2764 dead store that cannot be eliminated (because the
2765 same insn does something useful). Indicate this
2766 by marking the reg being set as dying here. */
2768 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2773 if (flags
& PROP_DEATH_NOTES
)
2775 /* This is a case where we have a multi-word hard register
2776 and some, but not all, of the words of the register are
2777 needed in subsequent insns. Write REG_UNUSED notes
2778 for those parts that were not needed. This case should
2781 for (i
= regno_first
; i
<= regno_last
; ++i
)
2782 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2784 = alloc_EXPR_LIST (REG_UNUSED
,
2785 gen_rtx_REG (reg_raw_mode
[i
], i
),
2791 /* Mark the register as being dead. */
2793 /* The stack pointer is never dead. Well, not strictly true,
2794 but it's very difficult to tell from here. Hopefully
2795 combine_stack_adjustments will fix up the most egregious
2797 && regno_first
!= STACK_POINTER_REGNUM
)
2799 for (i
= regno_first
; i
<= regno_last
; ++i
)
2800 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2801 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2804 else if (GET_CODE (reg
) == REG
)
2806 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2807 pbi
->reg_next_use
[regno_first
] = 0;
2810 /* If this is the last pass and this is a SCRATCH, show it will be dying
2811 here and count it. */
2812 else if (GET_CODE (reg
) == SCRATCH
)
2814 if (flags
& PROP_DEATH_NOTES
)
2816 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2820 #ifdef HAVE_conditional_execution
2821 /* Mark REGNO conditionally dead.
2822 Return true if the register is now unconditionally dead. */
2825 mark_regno_cond_dead (pbi
, regno
, cond
)
2826 struct propagate_block_info
*pbi
;
2830 /* If this is a store to a predicate register, the value of the
2831 predicate is changing, we don't know that the predicate as seen
2832 before is the same as that seen after. Flush all dependent
2833 conditions from reg_cond_dead. This will make all such
2834 conditionally live registers unconditionally live. */
2835 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2836 flush_reg_cond_reg (pbi
, regno
);
2838 /* If this is an unconditional store, remove any conditional
2839 life that may have existed. */
2840 if (cond
== NULL_RTX
)
2841 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2844 splay_tree_node node
;
2845 struct reg_cond_life_info
*rcli
;
2848 /* Otherwise this is a conditional set. Record that fact.
2849 It may have been conditionally used, or there may be a
2850 subsequent set with a complimentary condition. */
2852 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2855 /* The register was unconditionally live previously.
2856 Record the current condition as the condition under
2857 which it is dead. */
2858 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2859 rcli
->condition
= cond
;
2860 rcli
->stores
= cond
;
2861 rcli
->orig_condition
= const0_rtx
;
2862 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2863 (splay_tree_value
) rcli
);
2865 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2867 /* Not unconditionally dead. */
2872 /* The register was conditionally live previously.
2873 Add the new condition to the old. */
2874 rcli
= (struct reg_cond_life_info
*) node
->value
;
2875 ncond
= rcli
->condition
;
2876 ncond
= ior_reg_cond (ncond
, cond
, 1);
2877 if (rcli
->stores
== const0_rtx
)
2878 rcli
->stores
= cond
;
2879 else if (rcli
->stores
!= const1_rtx
)
2880 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2882 /* If the register is now unconditionally dead, remove the entry
2883 in the splay_tree. A register is unconditionally dead if the
2884 dead condition ncond is true. A register is also unconditionally
2885 dead if the sum of all conditional stores is an unconditional
2886 store (stores is true), and the dead condition is identically the
2887 same as the original dead condition initialized at the end of
2888 the block. This is a pointer compare, not an rtx_equal_p
2890 if (ncond
== const1_rtx
2891 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2892 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2895 rcli
->condition
= ncond
;
2897 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2899 /* Not unconditionally dead. */
2908 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2911 free_reg_cond_life_info (value
)
2912 splay_tree_value value
;
2914 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2918 /* Helper function for flush_reg_cond_reg. */
2921 flush_reg_cond_reg_1 (node
, data
)
2922 splay_tree_node node
;
2925 struct reg_cond_life_info
*rcli
;
2926 int *xdata
= (int *) data
;
2927 unsigned int regno
= xdata
[0];
2929 /* Don't need to search if last flushed value was farther on in
2930 the in-order traversal. */
2931 if (xdata
[1] >= (int) node
->key
)
2934 /* Splice out portions of the expression that refer to regno. */
2935 rcli
= (struct reg_cond_life_info
*) node
->value
;
2936 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2937 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2938 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2940 /* If the entire condition is now false, signal the node to be removed. */
2941 if (rcli
->condition
== const0_rtx
)
2943 xdata
[1] = node
->key
;
2946 else if (rcli
->condition
== const1_rtx
)
2952 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2955 flush_reg_cond_reg (pbi
, regno
)
2956 struct propagate_block_info
*pbi
;
2963 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2964 flush_reg_cond_reg_1
, pair
) == -1)
2965 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
2967 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
2970 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2971 For ior/and, the ADD flag determines whether we want to add the new
2972 condition X to the old one unconditionally. If it is zero, we will
2973 only return a new expression if X allows us to simplify part of
2974 OLD, otherwise we return NULL to the caller.
2975 If ADD is nonzero, we will return a new condition in all cases. The
2976 toplevel caller of one of these functions should always pass 1 for
2980 ior_reg_cond (old
, x
, add
)
2986 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
2988 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
2989 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
2990 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2992 if (GET_CODE (x
) == GET_CODE (old
)
2993 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2997 return gen_rtx_IOR (0, old
, x
);
3000 switch (GET_CODE (old
))
3003 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3004 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3005 if (op0
!= NULL
|| op1
!= NULL
)
3007 if (op0
== const0_rtx
)
3008 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3009 if (op1
== const0_rtx
)
3010 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3011 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3014 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3015 else if (rtx_equal_p (x
, op0
))
3016 /* (x | A) | x ~ (x | A). */
3019 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3020 else if (rtx_equal_p (x
, op1
))
3021 /* (A | x) | x ~ (A | x). */
3023 return gen_rtx_IOR (0, op0
, op1
);
3027 return gen_rtx_IOR (0, old
, x
);
3030 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3031 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3032 if (op0
!= NULL
|| op1
!= NULL
)
3034 if (op0
== const1_rtx
)
3035 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3036 if (op1
== const1_rtx
)
3037 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3038 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3041 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3042 else if (rtx_equal_p (x
, op0
))
3043 /* (x & A) | x ~ x. */
3046 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3047 else if (rtx_equal_p (x
, op1
))
3048 /* (A & x) | x ~ x. */
3050 return gen_rtx_AND (0, op0
, op1
);
3054 return gen_rtx_IOR (0, old
, x
);
3057 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3059 return not_reg_cond (op0
);
3062 return gen_rtx_IOR (0, old
, x
);
3073 enum rtx_code x_code
;
3075 if (x
== const0_rtx
)
3077 else if (x
== const1_rtx
)
3079 x_code
= GET_CODE (x
);
3082 if (GET_RTX_CLASS (x_code
) == '<'
3083 && GET_CODE (XEXP (x
, 0)) == REG
)
3085 if (XEXP (x
, 1) != const0_rtx
)
3088 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3089 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3091 return gen_rtx_NOT (0, x
);
3095 and_reg_cond (old
, x
, add
)
3101 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3103 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3104 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3105 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3107 if (GET_CODE (x
) == GET_CODE (old
)
3108 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3112 return gen_rtx_AND (0, old
, x
);
3115 switch (GET_CODE (old
))
3118 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3119 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3120 if (op0
!= NULL
|| op1
!= NULL
)
3122 if (op0
== const0_rtx
)
3123 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3124 if (op1
== const0_rtx
)
3125 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3126 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3129 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3130 else if (rtx_equal_p (x
, op0
))
3131 /* (x | A) & x ~ x. */
3134 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3135 else if (rtx_equal_p (x
, op1
))
3136 /* (A | x) & x ~ x. */
3138 return gen_rtx_IOR (0, op0
, op1
);
3142 return gen_rtx_AND (0, old
, x
);
3145 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3146 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3147 if (op0
!= NULL
|| op1
!= NULL
)
3149 if (op0
== const1_rtx
)
3150 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3151 if (op1
== const1_rtx
)
3152 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3153 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3156 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3157 else if (rtx_equal_p (x
, op0
))
3158 /* (x & A) & x ~ (x & A). */
3161 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3162 else if (rtx_equal_p (x
, op1
))
3163 /* (A & x) & x ~ (A & x). */
3165 return gen_rtx_AND (0, op0
, op1
);
3169 return gen_rtx_AND (0, old
, x
);
3172 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3174 return not_reg_cond (op0
);
3177 return gen_rtx_AND (0, old
, x
);
3184 /* Given a condition X, remove references to reg REGNO and return the
3185 new condition. The removal will be done so that all conditions
3186 involving REGNO are considered to evaluate to false. This function
3187 is used when the value of REGNO changes. */
3190 elim_reg_cond (x
, regno
)
3196 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3198 if (REGNO (XEXP (x
, 0)) == regno
)
3203 switch (GET_CODE (x
))
3206 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3207 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3208 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3210 if (op0
== const1_rtx
)
3212 if (op1
== const1_rtx
)
3214 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3216 return gen_rtx_AND (0, op0
, op1
);
3219 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3220 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3221 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3223 if (op0
== const0_rtx
)
3225 if (op1
== const0_rtx
)
3227 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3229 return gen_rtx_IOR (0, op0
, op1
);
3232 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3233 if (op0
== const0_rtx
)
3235 if (op0
== const1_rtx
)
3237 if (op0
!= XEXP (x
, 0))
3238 return not_reg_cond (op0
);
3245 #endif /* HAVE_conditional_execution */
3249 /* Try to substitute the auto-inc expression INC as the address inside
3250 MEM which occurs in INSN. Currently, the address of MEM is an expression
3251 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3252 that has a single set whose source is a PLUS of INCR_REG and something
3256 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3257 struct propagate_block_info
*pbi
;
3258 rtx inc
, insn
, mem
, incr
, incr_reg
;
3260 int regno
= REGNO (incr_reg
);
3261 rtx set
= single_set (incr
);
3262 rtx q
= SET_DEST (set
);
3263 rtx y
= SET_SRC (set
);
3264 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3266 /* Make sure this reg appears only once in this insn. */
3267 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3270 if (dead_or_set_p (incr
, incr_reg
)
3271 /* Mustn't autoinc an eliminable register. */
3272 && (regno
>= FIRST_PSEUDO_REGISTER
3273 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3275 /* This is the simple case. Try to make the auto-inc. If
3276 we can't, we are done. Otherwise, we will do any
3277 needed updates below. */
3278 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3281 else if (GET_CODE (q
) == REG
3282 /* PREV_INSN used here to check the semi-open interval
3284 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3285 /* We must also check for sets of q as q may be
3286 a call clobbered hard register and there may
3287 be a call between PREV_INSN (insn) and incr. */
3288 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3290 /* We have *p followed sometime later by q = p+size.
3291 Both p and q must be live afterward,
3292 and q is not used between INSN and its assignment.
3293 Change it to q = p, ...*q..., q = q+size.
3294 Then fall into the usual case. */
3298 emit_move_insn (q
, incr_reg
);
3299 insns
= get_insns ();
3302 /* If we can't make the auto-inc, or can't make the
3303 replacement into Y, exit. There's no point in making
3304 the change below if we can't do the auto-inc and doing
3305 so is not correct in the pre-inc case. */
3308 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3309 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3310 if (! apply_change_group ())
3313 /* We now know we'll be doing this change, so emit the
3314 new insn(s) and do the updates. */
3315 emit_insns_before (insns
, insn
);
3317 if (pbi
->bb
->head
== insn
)
3318 pbi
->bb
->head
= insns
;
3320 /* INCR will become a NOTE and INSN won't contain a
3321 use of INCR_REG. If a use of INCR_REG was just placed in
3322 the insn before INSN, make that the next use.
3323 Otherwise, invalidate it. */
3324 if (GET_CODE (PREV_INSN (insn
)) == INSN
3325 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3326 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3327 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3329 pbi
->reg_next_use
[regno
] = 0;
3334 /* REGNO is now used in INCR which is below INSN, but
3335 it previously wasn't live here. If we don't mark
3336 it as live, we'll put a REG_DEAD note for it
3337 on this insn, which is incorrect. */
3338 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3340 /* If there are any calls between INSN and INCR, show
3341 that REGNO now crosses them. */
3342 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3343 if (GET_CODE (temp
) == CALL_INSN
)
3344 REG_N_CALLS_CROSSED (regno
)++;
3346 /* Invalidate alias info for Q since we just changed its value. */
3347 clear_reg_alias_info (q
);
3352 /* If we haven't returned, it means we were able to make the
3353 auto-inc, so update the status. First, record that this insn
3354 has an implicit side effect. */
3356 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3358 /* Modify the old increment-insn to simply copy
3359 the already-incremented value of our register. */
3360 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3363 /* If that makes it a no-op (copying the register into itself) delete
3364 it so it won't appear to be a "use" and a "set" of this
3366 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3368 /* If the original source was dead, it's dead now. */
3371 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3373 remove_note (incr
, note
);
3374 if (XEXP (note
, 0) != incr_reg
)
3375 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3378 PUT_CODE (incr
, NOTE
);
3379 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3380 NOTE_SOURCE_FILE (incr
) = 0;
3383 if (regno
>= FIRST_PSEUDO_REGISTER
)
3385 /* Count an extra reference to the reg. When a reg is
3386 incremented, spilling it is worse, so we want to make
3387 that less likely. */
3388 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3390 /* Count the increment as a setting of the register,
3391 even though it isn't a SET in rtl. */
3392 REG_N_SETS (regno
)++;
3396 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3400 find_auto_inc (pbi
, x
, insn
)
3401 struct propagate_block_info
*pbi
;
3405 rtx addr
= XEXP (x
, 0);
3406 HOST_WIDE_INT offset
= 0;
3407 rtx set
, y
, incr
, inc_val
;
3409 int size
= GET_MODE_SIZE (GET_MODE (x
));
3411 if (GET_CODE (insn
) == JUMP_INSN
)
3414 /* Here we detect use of an index register which might be good for
3415 postincrement, postdecrement, preincrement, or predecrement. */
3417 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3418 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3420 if (GET_CODE (addr
) != REG
)
3423 regno
= REGNO (addr
);
3425 /* Is the next use an increment that might make auto-increment? */
3426 incr
= pbi
->reg_next_use
[regno
];
3427 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3429 set
= single_set (incr
);
3430 if (set
== 0 || GET_CODE (set
) != SET
)
3434 if (GET_CODE (y
) != PLUS
)
3437 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3438 inc_val
= XEXP (y
, 1);
3439 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3440 inc_val
= XEXP (y
, 0);
3444 if (GET_CODE (inc_val
) == CONST_INT
)
3446 if (HAVE_POST_INCREMENT
3447 && (INTVAL (inc_val
) == size
&& offset
== 0))
3448 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3450 else if (HAVE_POST_DECREMENT
3451 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3452 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3454 else if (HAVE_PRE_INCREMENT
3455 && (INTVAL (inc_val
) == size
&& offset
== size
))
3456 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3458 else if (HAVE_PRE_DECREMENT
3459 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3460 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3462 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3463 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3464 gen_rtx_PLUS (Pmode
,
3467 insn
, x
, incr
, addr
);
3469 else if (GET_CODE (inc_val
) == REG
3470 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3474 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3475 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3476 gen_rtx_PLUS (Pmode
,
3479 insn
, x
, incr
, addr
);
3483 #endif /* AUTO_INC_DEC */
3486 mark_used_reg (pbi
, reg
, cond
, insn
)
3487 struct propagate_block_info
*pbi
;
3489 rtx cond ATTRIBUTE_UNUSED
;
3492 unsigned int regno_first
, regno_last
, i
;
3493 int some_was_live
, some_was_dead
, some_not_set
;
3495 regno_last
= regno_first
= REGNO (reg
);
3496 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3497 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3499 /* Find out if any of this register is live after this instruction. */
3500 some_was_live
= some_was_dead
= 0;
3501 for (i
= regno_first
; i
<= regno_last
; ++i
)
3503 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3504 some_was_live
|= needed_regno
;
3505 some_was_dead
|= ! needed_regno
;
3508 /* Find out if any of the register was set this insn. */
3510 for (i
= regno_first
; i
<= regno_last
; ++i
)
3511 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3513 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3515 /* Record where each reg is used, so when the reg is set we know
3516 the next insn that uses it. */
3517 pbi
->reg_next_use
[regno_first
] = insn
;
3520 if (pbi
->flags
& PROP_REG_INFO
)
3522 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3524 /* If this is a register we are going to try to eliminate,
3525 don't mark it live here. If we are successful in
3526 eliminating it, it need not be live unless it is used for
3527 pseudos, in which case it will have been set live when it
3528 was allocated to the pseudos. If the register will not
3529 be eliminated, reload will set it live at that point.
3531 Otherwise, record that this function uses this register. */
3532 /* ??? The PPC backend tries to "eliminate" on the pic
3533 register to itself. This should be fixed. In the mean
3534 time, hack around it. */
3536 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3537 && (regno_first
== FRAME_POINTER_REGNUM
3538 || regno_first
== ARG_POINTER_REGNUM
)))
3539 for (i
= regno_first
; i
<= regno_last
; ++i
)
3540 regs_ever_live
[i
] = 1;
3544 /* Keep track of which basic block each reg appears in. */
3546 int blocknum
= pbi
->bb
->index
;
3547 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3548 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3549 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3550 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3552 /* Count (weighted) number of uses of each reg. */
3553 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3554 REG_N_REFS (regno_first
)++;
3558 /* Record and count the insns in which a reg dies. If it is used in
3559 this insn and was dead below the insn then it dies in this insn.
3560 If it was set in this insn, we do not make a REG_DEAD note;
3561 likewise if we already made such a note. */
3562 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3566 /* Check for the case where the register dying partially
3567 overlaps the register set by this insn. */
3568 if (regno_first
!= regno_last
)
3569 for (i
= regno_first
; i
<= regno_last
; ++i
)
3570 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3572 /* If none of the words in X is needed, make a REG_DEAD note.
3573 Otherwise, we must make partial REG_DEAD notes. */
3574 if (! some_was_live
)
3576 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3577 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3579 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3581 if (pbi
->flags
& PROP_REG_INFO
)
3582 REG_N_DEATHS (regno_first
)++;
3586 /* Don't make a REG_DEAD note for a part of a register
3587 that is set in the insn. */
3588 for (i
= regno_first
; i
<= regno_last
; ++i
)
3589 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3590 && ! dead_or_set_regno_p (insn
, i
))
3592 = alloc_EXPR_LIST (REG_DEAD
,
3593 gen_rtx_REG (reg_raw_mode
[i
], i
),
3598 /* Mark the register as being live. */
3599 for (i
= regno_first
; i
<= regno_last
; ++i
)
3601 #ifdef HAVE_conditional_execution
3602 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3605 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3607 #ifdef HAVE_conditional_execution
3608 /* If this is a conditional use, record that fact. If it is later
3609 conditionally set, we'll know to kill the register. */
3610 if (cond
!= NULL_RTX
)
3612 splay_tree_node node
;
3613 struct reg_cond_life_info
*rcli
;
3618 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3621 /* The register was unconditionally live previously.
3622 No need to do anything. */
3626 /* The register was conditionally live previously.
3627 Subtract the new life cond from the old death cond. */
3628 rcli
= (struct reg_cond_life_info
*) node
->value
;
3629 ncond
= rcli
->condition
;
3630 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3632 /* If the register is now unconditionally live,
3633 remove the entry in the splay_tree. */
3634 if (ncond
== const0_rtx
)
3635 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3638 rcli
->condition
= ncond
;
3639 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3640 REGNO (XEXP (cond
, 0)));
3646 /* The register was not previously live at all. Record
3647 the condition under which it is still dead. */
3648 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3649 rcli
->condition
= not_reg_cond (cond
);
3650 rcli
->stores
= const0_rtx
;
3651 rcli
->orig_condition
= const0_rtx
;
3652 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3653 (splay_tree_value
) rcli
);
3655 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3658 else if (this_was_live
)
3660 /* The register may have been conditionally live previously, but
3661 is now unconditionally live. Remove it from the conditionally
3662 dead list, so that a conditional set won't cause us to think
3664 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3670 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3671 This is done assuming the registers needed from X are those that
3672 have 1-bits in PBI->REG_LIVE.
3674 INSN is the containing instruction. If INSN is dead, this function
3678 mark_used_regs (pbi
, x
, cond
, insn
)
3679 struct propagate_block_info
*pbi
;
3684 int flags
= pbi
->flags
;
3689 code
= GET_CODE (x
);
3710 /* If we are clobbering a MEM, mark any registers inside the address
3712 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3713 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3717 /* Don't bother watching stores to mems if this is not the
3718 final pass. We'll not be deleting dead stores this round. */
3719 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3721 /* Invalidate the data for the last MEM stored, but only if MEM is
3722 something that can be stored into. */
3723 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3724 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3725 /* Needn't clear the memory set list. */
3729 rtx temp
= pbi
->mem_set_list
;
3730 rtx prev
= NULL_RTX
;
3735 next
= XEXP (temp
, 1);
3736 if (anti_dependence (XEXP (temp
, 0), x
))
3738 /* Splice temp out of the list. */
3740 XEXP (prev
, 1) = next
;
3742 pbi
->mem_set_list
= next
;
3743 free_EXPR_LIST_node (temp
);
3744 pbi
->mem_set_list_len
--;
3752 /* If the memory reference had embedded side effects (autoincrement
3753 address modes. Then we may need to kill some entries on the
3756 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3760 if (flags
& PROP_AUTOINC
)
3761 find_auto_inc (pbi
, x
, insn
);
3766 #ifdef CLASS_CANNOT_CHANGE_MODE
3767 if (GET_CODE (SUBREG_REG (x
)) == REG
3768 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3769 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3770 GET_MODE (SUBREG_REG (x
))))
3771 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3774 /* While we're here, optimize this case. */
3776 if (GET_CODE (x
) != REG
)
3781 /* See a register other than being set => mark it as needed. */
3782 mark_used_reg (pbi
, x
, cond
, insn
);
3787 rtx testreg
= SET_DEST (x
);
3790 /* If storing into MEM, don't show it as being used. But do
3791 show the address as being used. */
3792 if (GET_CODE (testreg
) == MEM
)
3795 if (flags
& PROP_AUTOINC
)
3796 find_auto_inc (pbi
, testreg
, insn
);
3798 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3799 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3803 /* Storing in STRICT_LOW_PART is like storing in a reg
3804 in that this SET might be dead, so ignore it in TESTREG.
3805 but in some other ways it is like using the reg.
3807 Storing in a SUBREG or a bit field is like storing the entire
3808 register in that if the register's value is not used
3809 then this SET is not needed. */
3810 while (GET_CODE (testreg
) == STRICT_LOW_PART
3811 || GET_CODE (testreg
) == ZERO_EXTRACT
3812 || GET_CODE (testreg
) == SIGN_EXTRACT
3813 || GET_CODE (testreg
) == SUBREG
)
3815 #ifdef CLASS_CANNOT_CHANGE_MODE
3816 if (GET_CODE (testreg
) == SUBREG
3817 && GET_CODE (SUBREG_REG (testreg
)) == REG
3818 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3819 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3820 GET_MODE (testreg
)))
3821 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3824 /* Modifying a single register in an alternate mode
3825 does not use any of the old value. But these other
3826 ways of storing in a register do use the old value. */
3827 if (GET_CODE (testreg
) == SUBREG
3828 && !((REG_BYTES (SUBREG_REG (testreg
))
3829 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3830 > (REG_BYTES (testreg
)
3831 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3836 testreg
= XEXP (testreg
, 0);
3839 /* If this is a store into a register or group of registers,
3840 recursively scan the value being stored. */
3842 if ((GET_CODE (testreg
) == PARALLEL
3843 && GET_MODE (testreg
) == BLKmode
)
3844 || (GET_CODE (testreg
) == REG
3845 && (regno
= REGNO (testreg
),
3846 ! (regno
== FRAME_POINTER_REGNUM
3847 && (! reload_completed
|| frame_pointer_needed
)))
3848 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3849 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3850 && (! reload_completed
|| frame_pointer_needed
))
3852 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3853 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3858 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3859 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3866 case UNSPEC_VOLATILE
:
3870 /* Traditional and volatile asm instructions must be considered to use
3871 and clobber all hard registers, all pseudo-registers and all of
3872 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3874 Consider for instance a volatile asm that changes the fpu rounding
3875 mode. An insn should not be moved across this even if it only uses
3876 pseudo-regs because it might give an incorrectly rounded result.
3878 ?!? Unfortunately, marking all hard registers as live causes massive
3879 problems for the register allocator and marking all pseudos as live
3880 creates mountains of uninitialized variable warnings.
3882 So for now, just clear the memory set list and mark any regs
3883 we can find in ASM_OPERANDS as used. */
3884 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3886 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3887 pbi
->mem_set_list_len
= 0;
3890 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3891 We can not just fall through here since then we would be confused
3892 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3893 traditional asms unlike their normal usage. */
3894 if (code
== ASM_OPERANDS
)
3898 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3899 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3905 if (cond
!= NULL_RTX
)
3908 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3910 cond
= COND_EXEC_TEST (x
);
3911 x
= COND_EXEC_CODE (x
);
3915 /* We _do_not_ want to scan operands of phi nodes. Operands of
3916 a phi function are evaluated only when control reaches this
3917 block along a particular edge. Therefore, regs that appear
3918 as arguments to phi should not be added to the global live at
3926 /* Recursively scan the operands of this expression. */
3929 const char * const fmt
= GET_RTX_FORMAT (code
);
3932 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3936 /* Tail recursive case: save a function call level. */
3942 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3944 else if (fmt
[i
] == 'E')
3947 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3948 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3957 try_pre_increment_1 (pbi
, insn
)
3958 struct propagate_block_info
*pbi
;
3961 /* Find the next use of this reg. If in same basic block,
3962 make it do pre-increment or pre-decrement if appropriate. */
3963 rtx x
= single_set (insn
);
3964 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3965 * INTVAL (XEXP (SET_SRC (x
), 1)));
3966 int regno
= REGNO (SET_DEST (x
));
3967 rtx y
= pbi
->reg_next_use
[regno
];
3969 && SET_DEST (x
) != stack_pointer_rtx
3970 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
3971 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3972 mode would be better. */
3973 && ! dead_or_set_p (y
, SET_DEST (x
))
3974 && try_pre_increment (y
, SET_DEST (x
), amount
))
3976 /* We have found a suitable auto-increment and already changed
3977 insn Y to do it. So flush this increment instruction. */
3978 propagate_block_delete_insn (insn
);
3980 /* Count a reference to this reg for the increment insn we are
3981 deleting. When a reg is incremented, spilling it is worse,
3982 so we want to make that less likely. */
3983 if (regno
>= FIRST_PSEUDO_REGISTER
)
3985 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3986 REG_N_SETS (regno
)++;
3989 /* Flush any remembered memories depending on the value of
3990 the incremented register. */
3991 invalidate_mems_from_set (pbi
, SET_DEST (x
));
3998 /* Try to change INSN so that it does pre-increment or pre-decrement
3999 addressing on register REG in order to add AMOUNT to REG.
4000 AMOUNT is negative for pre-decrement.
4001 Returns 1 if the change could be made.
4002 This checks all about the validity of the result of modifying INSN. */
4005 try_pre_increment (insn
, reg
, amount
)
4007 HOST_WIDE_INT amount
;
4011 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4012 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4014 /* Nonzero if we can try to make a post-increment or post-decrement.
4015 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4016 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4017 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4020 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4023 /* From the sign of increment, see which possibilities are conceivable
4024 on this target machine. */
4025 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4027 if (HAVE_POST_INCREMENT
&& amount
> 0)
4030 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4032 if (HAVE_POST_DECREMENT
&& amount
< 0)
4035 if (! (pre_ok
|| post_ok
))
4038 /* It is not safe to add a side effect to a jump insn
4039 because if the incremented register is spilled and must be reloaded
4040 there would be no way to store the incremented value back in memory. */
4042 if (GET_CODE (insn
) == JUMP_INSN
)
4047 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4048 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4050 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4054 if (use
== 0 || use
== (rtx
) (size_t) 1)
4057 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4060 /* See if this combination of instruction and addressing mode exists. */
4061 if (! validate_change (insn
, &XEXP (use
, 0),
4062 gen_rtx_fmt_e (amount
> 0
4063 ? (do_post
? POST_INC
: PRE_INC
)
4064 : (do_post
? POST_DEC
: PRE_DEC
),
4068 /* Record that this insn now has an implicit side effect on X. */
4069 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4073 #endif /* AUTO_INC_DEC */
4075 /* Find the place in the rtx X where REG is used as a memory address.
4076 Return the MEM rtx that so uses it.
4077 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4078 (plus REG (const_int PLUSCONST)).
4080 If such an address does not appear, return 0.
4081 If REG appears more than once, or is used other than in such an address,
4085 find_use_as_address (x
, reg
, plusconst
)
4088 HOST_WIDE_INT plusconst
;
4090 enum rtx_code code
= GET_CODE (x
);
4091 const char * const fmt
= GET_RTX_FORMAT (code
);
4096 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4099 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4100 && XEXP (XEXP (x
, 0), 0) == reg
4101 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4102 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4105 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4107 /* If REG occurs inside a MEM used in a bit-field reference,
4108 that is unacceptable. */
4109 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4110 return (rtx
) (size_t) 1;
4114 return (rtx
) (size_t) 1;
4116 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4120 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4124 return (rtx
) (size_t) 1;
4126 else if (fmt
[i
] == 'E')
4129 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4131 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4135 return (rtx
) (size_t) 1;
4143 /* Write information about registers and basic blocks into FILE.
4144 This is part of making a debugging dump. */
4147 dump_regset (r
, outf
)
4154 fputs (" (nil)", outf
);
4158 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4160 fprintf (outf
, " %d", i
);
4161 if (i
< FIRST_PSEUDO_REGISTER
)
4162 fprintf (outf
, " [%s]",
4167 /* Print a human-reaable representation of R on the standard error
4168 stream. This function is designed to be used from within the
4175 dump_regset (r
, stderr
);
4176 putc ('\n', stderr
);
4179 /* Recompute register set/reference counts immediately prior to register
4182 This avoids problems with set/reference counts changing to/from values
4183 which have special meanings to the register allocators.
4185 Additionally, the reference counts are the primary component used by the
4186 register allocators to prioritize pseudos for allocation to hard regs.
4187 More accurate reference counts generally lead to better register allocation.
4189 F is the first insn to be scanned.
4191 LOOP_STEP denotes how much loop_depth should be incremented per
4192 loop nesting level in order to increase the ref count more for
4193 references in a loop.
4195 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4196 possibly other information which is used by the register allocators. */
4199 recompute_reg_usage (f
, loop_step
)
4200 rtx f ATTRIBUTE_UNUSED
;
4201 int loop_step ATTRIBUTE_UNUSED
;
4203 allocate_reg_life_data ();
4204 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4207 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4208 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4209 of the number of registers that died. */
4212 count_or_remove_death_notes (blocks
, kill
)
4219 FOR_EACH_BB_REVERSE (bb
)
4223 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4226 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4230 rtx
*pprev
= ®_NOTES (insn
);
4235 switch (REG_NOTE_KIND (link
))
4238 if (GET_CODE (XEXP (link
, 0)) == REG
)
4240 rtx reg
= XEXP (link
, 0);
4243 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4246 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4254 rtx next
= XEXP (link
, 1);
4255 free_EXPR_LIST_node (link
);
4256 *pprev
= link
= next
;
4262 pprev
= &XEXP (link
, 1);
4269 if (insn
== bb
->end
)
4276 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4277 if blocks is NULL. */
4280 clear_log_links (blocks
)
4288 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4290 free_INSN_LIST_list (&LOG_LINKS (insn
));
4293 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4295 basic_block bb
= BASIC_BLOCK (i
);
4297 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4298 insn
= NEXT_INSN (insn
))
4300 free_INSN_LIST_list (&LOG_LINKS (insn
));
4304 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4305 correspond to the hard registers, if any, set in that map. This
4306 could be done far more efficiently by having all sorts of special-cases
4307 with moving single words, but probably isn't worth the trouble. */
4310 reg_set_to_hard_reg_set (to
, from
)
4316 EXECUTE_IF_SET_IN_BITMAP
4319 if (i
>= FIRST_PSEUDO_REGISTER
)
4321 SET_HARD_REG_BIT (*to
, i
);