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
))
1118 /* We clean aux when we remove the initially-enqueued bbs, but we
1119 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1121 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1124 sbitmap_zero (blocks_out
);
1126 /* We work through the queue until there are no more blocks. What
1127 is live at the end of this block is precisely the union of what
1128 is live at the beginning of all its successors. So, we set its
1129 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1130 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1131 this block by walking through the instructions in this block in
1132 reverse order and updating as we go. If that changed
1133 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1134 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1136 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1137 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1138 must either be live at the end of the block, or used within the
1139 block. In the latter case, it will certainly never disappear
1140 from GLOBAL_LIVE_AT_START. In the former case, the register
1141 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1142 for one of the successor blocks. By induction, that cannot
1144 while (qhead
!= qtail
)
1146 int rescan
, changed
;
1155 /* Begin by propagating live_at_start from the successor blocks. */
1156 CLEAR_REG_SET (new_live_at_end
);
1159 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1161 basic_block sb
= e
->dest
;
1163 /* Call-clobbered registers die across exception and
1165 /* ??? Abnormal call edges ignored for the moment, as this gets
1166 confused by sibling call edges, which crashes reg-stack. */
1167 if (e
->flags
& EDGE_EH
)
1169 bitmap_operation (tmp
, sb
->global_live_at_start
,
1170 call_used
, BITMAP_AND_COMPL
);
1171 IOR_REG_SET (new_live_at_end
, tmp
);
1174 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1176 /* If a target saves one register in another (instead of on
1177 the stack) the save register will need to be live for EH. */
1178 if (e
->flags
& EDGE_EH
)
1179 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1181 SET_REGNO_REG_SET (new_live_at_end
, i
);
1185 /* This might be a noreturn function that throws. And
1186 even if it isn't, getting the unwind info right helps
1188 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1190 SET_REGNO_REG_SET (new_live_at_end
, i
);
1193 /* The all-important stack pointer must always be live. */
1194 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1196 /* Before reload, there are a few registers that must be forced
1197 live everywhere -- which might not already be the case for
1198 blocks within infinite loops. */
1199 if (! reload_completed
)
1201 /* Any reference to any pseudo before reload is a potential
1202 reference of the frame pointer. */
1203 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1205 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1206 /* Pseudos with argument area equivalences may require
1207 reloading via the argument pointer. */
1208 if (fixed_regs
[ARG_POINTER_REGNUM
])
1209 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1212 /* Any constant, or pseudo with constant equivalences, may
1213 require reloading from memory using the pic register. */
1214 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1215 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1216 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1219 /* Regs used in phi nodes are not included in
1220 global_live_at_start, since they are live only along a
1221 particular edge. Set those regs that are live because of a
1222 phi node alternative corresponding to this particular block. */
1224 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1227 if (bb
== ENTRY_BLOCK_PTR
)
1229 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1233 /* On our first pass through this block, we'll go ahead and continue.
1234 Recognize first pass by local_set NULL. On subsequent passes, we
1235 get to skip out early if live_at_end wouldn't have changed. */
1237 if (bb
->local_set
== NULL
)
1239 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1240 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1245 /* If any bits were removed from live_at_end, we'll have to
1246 rescan the block. This wouldn't be necessary if we had
1247 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1248 local_live is really dependent on live_at_end. */
1249 CLEAR_REG_SET (tmp
);
1250 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1251 new_live_at_end
, BITMAP_AND_COMPL
);
1255 /* If any of the registers in the new live_at_end set are
1256 conditionally set in this basic block, we must rescan.
1257 This is because conditional lifetimes at the end of the
1258 block do not just take the live_at_end set into account,
1259 but also the liveness at the start of each successor
1260 block. We can miss changes in those sets if we only
1261 compare the new live_at_end against the previous one. */
1262 CLEAR_REG_SET (tmp
);
1263 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1264 bb
->cond_local_set
, BITMAP_AND
);
1269 /* Find the set of changed bits. Take this opportunity
1270 to notice that this set is empty and early out. */
1271 CLEAR_REG_SET (tmp
);
1272 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1273 new_live_at_end
, BITMAP_XOR
);
1277 /* If any of the changed bits overlap with local_set,
1278 we'll have to rescan the block. Detect overlap by
1279 the AND with ~local_set turning off bits. */
1280 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1285 /* Let our caller know that BB changed enough to require its
1286 death notes updated. */
1288 SET_BIT (blocks_out
, bb
->index
);
1292 /* Add to live_at_start the set of all registers in
1293 new_live_at_end that aren't in the old live_at_end. */
1295 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1297 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1299 changed
= bitmap_operation (bb
->global_live_at_start
,
1300 bb
->global_live_at_start
,
1307 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1309 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1310 into live_at_start. */
1311 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1312 bb
->cond_local_set
, flags
);
1314 /* If live_at start didn't change, no need to go farther. */
1315 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1318 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1321 /* Queue all predecessors of BB so that we may re-examine
1322 their live_at_end. */
1323 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1325 basic_block pb
= e
->src
;
1326 if (pb
->aux
== NULL
)
1337 FREE_REG_SET (new_live_at_end
);
1338 FREE_REG_SET (call_used
);
1342 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1344 basic_block bb
= BASIC_BLOCK (i
);
1345 FREE_REG_SET (bb
->local_set
);
1346 FREE_REG_SET (bb
->cond_local_set
);
1353 FREE_REG_SET (bb
->local_set
);
1354 FREE_REG_SET (bb
->cond_local_set
);
1362 /* This structure is used to pass parameters to an from the
1363 the function find_regno_partial(). It is used to pass in the
1364 register number we are looking, as well as to return any rtx
1368 unsigned regno_to_find
;
1370 } find_regno_partial_param
;
1373 /* Find the rtx for the reg numbers specified in 'data' if it is
1374 part of an expression which only uses part of the register. Return
1375 it in the structure passed in. */
1377 find_regno_partial (ptr
, data
)
1381 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1382 unsigned reg
= param
->regno_to_find
;
1383 param
->retval
= NULL_RTX
;
1385 if (*ptr
== NULL_RTX
)
1388 switch (GET_CODE (*ptr
))
1392 case STRICT_LOW_PART
:
1393 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1395 param
->retval
= XEXP (*ptr
, 0);
1401 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1402 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1404 param
->retval
= SUBREG_REG (*ptr
);
1416 /* Process all immediate successors of the entry block looking for pseudo
1417 registers which are live on entry. Find all of those whose first
1418 instance is a partial register reference of some kind, and initialize
1419 them to 0 after the entry block. This will prevent bit sets within
1420 registers whose value is unknown, and may contain some kind of sticky
1421 bits we don't want. */
1424 initialize_uninitialized_subregs ()
1428 int reg
, did_something
= 0;
1429 find_regno_partial_param param
;
1431 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1433 basic_block bb
= e
->dest
;
1434 regset map
= bb
->global_live_at_start
;
1435 EXECUTE_IF_SET_IN_REG_SET (map
,
1436 FIRST_PSEUDO_REGISTER
, reg
,
1438 int uid
= REGNO_FIRST_UID (reg
);
1441 /* Find an insn which mentions the register we are looking for.
1442 Its preferable to have an instance of the register's rtl since
1443 there may be various flags set which we need to duplicate.
1444 If we can't find it, its probably an automatic whose initial
1445 value doesn't matter, or hopefully something we don't care about. */
1446 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1450 /* Found the insn, now get the REG rtx, if we can. */
1451 param
.regno_to_find
= reg
;
1452 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1453 if (param
.retval
!= NULL_RTX
)
1455 insn
= gen_move_insn (param
.retval
,
1456 CONST0_RTX (GET_MODE (param
.retval
)));
1457 insert_insn_on_edge (insn
, e
);
1465 commit_edge_insertions ();
1466 return did_something
;
1470 /* Subroutines of life analysis. */
1472 /* Allocate the permanent data structures that represent the results
1473 of life analysis. Not static since used also for stupid life analysis. */
1476 allocate_bb_life_data ()
1480 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1482 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1483 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1486 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1490 allocate_reg_life_data ()
1494 max_regno
= max_reg_num ();
1496 /* Recalculate the register space, in case it has grown. Old style
1497 vector oriented regsets would set regset_{size,bytes} here also. */
1498 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1500 /* Reset all the data we'll collect in propagate_block and its
1502 for (i
= 0; i
< max_regno
; i
++)
1506 REG_N_DEATHS (i
) = 0;
1507 REG_N_CALLS_CROSSED (i
) = 0;
1508 REG_LIVE_LENGTH (i
) = 0;
1509 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1513 /* Delete dead instructions for propagate_block. */
1516 propagate_block_delete_insn (insn
)
1519 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1521 /* If the insn referred to a label, and that label was attached to
1522 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1523 pretty much mandatory to delete it, because the ADDR_VEC may be
1524 referencing labels that no longer exist.
1526 INSN may reference a deleted label, particularly when a jump
1527 table has been optimized into a direct jump. There's no
1528 real good way to fix up the reference to the deleted label
1529 when the label is deleted, so we just allow it here. */
1531 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1533 rtx label
= XEXP (inote
, 0);
1536 /* The label may be forced if it has been put in the constant
1537 pool. If that is the only use we must discard the table
1538 jump following it, but not the label itself. */
1539 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1540 && (next
= next_nonnote_insn (label
)) != NULL
1541 && GET_CODE (next
) == JUMP_INSN
1542 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1543 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1545 rtx pat
= PATTERN (next
);
1546 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1547 int len
= XVECLEN (pat
, diff_vec_p
);
1550 for (i
= 0; i
< len
; i
++)
1551 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1553 delete_insn_and_edges (next
);
1558 delete_insn_and_edges (insn
);
1562 /* Delete dead libcalls for propagate_block. Return the insn
1563 before the libcall. */
1566 propagate_block_delete_libcall ( insn
, note
)
1569 rtx first
= XEXP (note
, 0);
1570 rtx before
= PREV_INSN (first
);
1572 delete_insn_chain_and_edges (first
, insn
);
1577 /* Update the life-status of regs for one insn. Return the previous insn. */
1580 propagate_one_insn (pbi
, insn
)
1581 struct propagate_block_info
*pbi
;
1584 rtx prev
= PREV_INSN (insn
);
1585 int flags
= pbi
->flags
;
1586 int insn_is_dead
= 0;
1587 int libcall_is_dead
= 0;
1591 if (! INSN_P (insn
))
1594 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1595 if (flags
& PROP_SCAN_DEAD_CODE
)
1597 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1598 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1599 && libcall_dead_p (pbi
, note
, insn
));
1602 /* If an instruction consists of just dead store(s) on final pass,
1604 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1606 /* If we're trying to delete a prologue or epilogue instruction
1607 that isn't flagged as possibly being dead, something is wrong.
1608 But if we are keeping the stack pointer depressed, we might well
1609 be deleting insns that are used to compute the amount to update
1610 it by, so they are fine. */
1611 if (reload_completed
1612 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1613 && (TYPE_RETURNS_STACK_DEPRESSED
1614 (TREE_TYPE (current_function_decl
))))
1615 && (((HAVE_epilogue
|| HAVE_prologue
)
1616 && prologue_epilogue_contains (insn
))
1617 || (HAVE_sibcall_epilogue
1618 && sibcall_epilogue_contains (insn
)))
1619 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1620 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1622 /* Record sets. Do this even for dead instructions, since they
1623 would have killed the values if they hadn't been deleted. */
1624 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1626 /* CC0 is now known to be dead. Either this insn used it,
1627 in which case it doesn't anymore, or clobbered it,
1628 so the next insn can't use it. */
1631 if (libcall_is_dead
)
1632 prev
= propagate_block_delete_libcall ( insn
, note
);
1634 propagate_block_delete_insn (insn
);
1639 /* See if this is an increment or decrement that can be merged into
1640 a following memory address. */
1643 rtx x
= single_set (insn
);
1645 /* Does this instruction increment or decrement a register? */
1646 if ((flags
& PROP_AUTOINC
)
1648 && GET_CODE (SET_DEST (x
)) == REG
1649 && (GET_CODE (SET_SRC (x
)) == PLUS
1650 || GET_CODE (SET_SRC (x
)) == MINUS
)
1651 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1652 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1653 /* Ok, look for a following memory ref we can combine with.
1654 If one is found, change the memory ref to a PRE_INC
1655 or PRE_DEC, cancel this insn, and return 1.
1656 Return 0 if nothing has been done. */
1657 && try_pre_increment_1 (pbi
, insn
))
1660 #endif /* AUTO_INC_DEC */
1662 CLEAR_REG_SET (pbi
->new_set
);
1664 /* If this is not the final pass, and this insn is copying the value of
1665 a library call and it's dead, don't scan the insns that perform the
1666 library call, so that the call's arguments are not marked live. */
1667 if (libcall_is_dead
)
1669 /* Record the death of the dest reg. */
1670 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1672 insn
= XEXP (note
, 0);
1673 return PREV_INSN (insn
);
1675 else if (GET_CODE (PATTERN (insn
)) == SET
1676 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1677 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1678 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1679 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1680 /* We have an insn to pop a constant amount off the stack.
1681 (Such insns use PLUS regardless of the direction of the stack,
1682 and any insn to adjust the stack by a constant is always a pop.)
1683 These insns, if not dead stores, have no effect on life, though
1684 they do have an effect on the memory stores we are tracking. */
1685 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1689 /* Any regs live at the time of a call instruction must not go
1690 in a register clobbered by calls. Find all regs now live and
1691 record this for them. */
1693 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1694 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1695 { REG_N_CALLS_CROSSED (i
)++; });
1697 /* Record sets. Do this even for dead instructions, since they
1698 would have killed the values if they hadn't been deleted. */
1699 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1701 if (GET_CODE (insn
) == CALL_INSN
)
1707 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1708 cond
= COND_EXEC_TEST (PATTERN (insn
));
1710 /* Non-constant calls clobber memory, constant calls do not
1711 clobber memory, though they may clobber outgoing arguments
1713 if (! CONST_OR_PURE_CALL_P (insn
))
1715 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1716 pbi
->mem_set_list_len
= 0;
1719 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1721 /* There may be extra registers to be clobbered. */
1722 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1724 note
= XEXP (note
, 1))
1725 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1726 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1727 cond
, insn
, pbi
->flags
);
1729 /* Calls change all call-used and global registers. */
1730 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1731 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1733 /* We do not want REG_UNUSED notes for these registers. */
1734 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1736 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1740 /* If an insn doesn't use CC0, it becomes dead since we assume
1741 that every insn clobbers it. So show it dead here;
1742 mark_used_regs will set it live if it is referenced. */
1747 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1748 if ((flags
& PROP_EQUAL_NOTES
)
1749 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1750 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1751 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1753 /* Sometimes we may have inserted something before INSN (such as a move)
1754 when we make an auto-inc. So ensure we will scan those insns. */
1756 prev
= PREV_INSN (insn
);
1759 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1765 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1766 cond
= COND_EXEC_TEST (PATTERN (insn
));
1768 /* Calls use their arguments. */
1769 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1771 note
= XEXP (note
, 1))
1772 if (GET_CODE (XEXP (note
, 0)) == USE
)
1773 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1776 /* The stack ptr is used (honorarily) by a CALL insn. */
1777 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1779 /* Calls may also reference any of the global registers,
1780 so they are made live. */
1781 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1783 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1788 /* On final pass, update counts of how many insns in which each reg
1790 if (flags
& PROP_REG_INFO
)
1791 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1792 { REG_LIVE_LENGTH (i
)++; });
1797 /* Initialize a propagate_block_info struct for public consumption.
1798 Note that the structure itself is opaque to this file, but that
1799 the user can use the regsets provided here. */
1801 struct propagate_block_info
*
1802 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1804 regset live
, local_set
, cond_local_set
;
1807 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1810 pbi
->reg_live
= live
;
1811 pbi
->mem_set_list
= NULL_RTX
;
1812 pbi
->mem_set_list_len
= 0;
1813 pbi
->local_set
= local_set
;
1814 pbi
->cond_local_set
= cond_local_set
;
1818 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1819 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1821 pbi
->reg_next_use
= NULL
;
1823 pbi
->new_set
= BITMAP_XMALLOC ();
1825 #ifdef HAVE_conditional_execution
1826 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1827 free_reg_cond_life_info
);
1828 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1830 /* If this block ends in a conditional branch, for each register live
1831 from one side of the branch and not the other, record the register
1832 as conditionally dead. */
1833 if (GET_CODE (bb
->end
) == JUMP_INSN
1834 && any_condjump_p (bb
->end
))
1836 regset_head diff_head
;
1837 regset diff
= INITIALIZE_REG_SET (diff_head
);
1838 basic_block bb_true
, bb_false
;
1839 rtx cond_true
, cond_false
, set_src
;
1842 /* Identify the successor blocks. */
1843 bb_true
= bb
->succ
->dest
;
1844 if (bb
->succ
->succ_next
!= NULL
)
1846 bb_false
= bb
->succ
->succ_next
->dest
;
1848 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1850 basic_block t
= bb_false
;
1854 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1859 /* This can happen with a conditional jump to the next insn. */
1860 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1863 /* Simplest way to do nothing. */
1867 /* Extract the condition from the branch. */
1868 set_src
= SET_SRC (pc_set (bb
->end
));
1869 cond_true
= XEXP (set_src
, 0);
1870 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1871 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1872 XEXP (cond_true
, 1));
1873 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1876 cond_false
= cond_true
;
1880 /* Compute which register lead different lives in the successors. */
1881 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1882 bb_false
->global_live_at_start
, BITMAP_XOR
))
1884 rtx reg
= XEXP (cond_true
, 0);
1886 if (GET_CODE (reg
) == SUBREG
)
1887 reg
= SUBREG_REG (reg
);
1889 if (GET_CODE (reg
) != REG
)
1892 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1894 /* For each such register, mark it conditionally dead. */
1895 EXECUTE_IF_SET_IN_REG_SET
1898 struct reg_cond_life_info
*rcli
;
1901 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1903 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1907 rcli
->condition
= cond
;
1908 rcli
->stores
= const0_rtx
;
1909 rcli
->orig_condition
= cond
;
1911 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1912 (splay_tree_value
) rcli
);
1916 FREE_REG_SET (diff
);
1920 /* If this block has no successors, any stores to the frame that aren't
1921 used later in the block are dead. So make a pass over the block
1922 recording any such that are made and show them dead at the end. We do
1923 a very conservative and simple job here. */
1925 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1926 && (TYPE_RETURNS_STACK_DEPRESSED
1927 (TREE_TYPE (current_function_decl
))))
1928 && (flags
& PROP_SCAN_DEAD_STORES
)
1929 && (bb
->succ
== NULL
1930 || (bb
->succ
->succ_next
== NULL
1931 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1932 && ! current_function_calls_eh_return
)))
1935 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1936 if (GET_CODE (insn
) == INSN
1937 && (set
= single_set (insn
))
1938 && GET_CODE (SET_DEST (set
)) == MEM
)
1940 rtx mem
= SET_DEST (set
);
1941 rtx canon_mem
= canon_rtx (mem
);
1943 /* This optimization is performed by faking a store to the
1944 memory at the end of the block. This doesn't work for
1945 unchanging memories because multiple stores to unchanging
1946 memory is illegal and alias analysis doesn't consider it. */
1947 if (RTX_UNCHANGING_P (canon_mem
))
1950 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1951 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1952 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1953 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1954 add_to_mem_set_list (pbi
, canon_mem
);
1961 /* Release a propagate_block_info struct. */
1964 free_propagate_block_info (pbi
)
1965 struct propagate_block_info
*pbi
;
1967 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1969 BITMAP_XFREE (pbi
->new_set
);
1971 #ifdef HAVE_conditional_execution
1972 splay_tree_delete (pbi
->reg_cond_dead
);
1973 BITMAP_XFREE (pbi
->reg_cond_reg
);
1976 if (pbi
->reg_next_use
)
1977 free (pbi
->reg_next_use
);
1982 /* Compute the registers live at the beginning of a basic block BB from
1983 those live at the end.
1985 When called, REG_LIVE contains those live at the end. On return, it
1986 contains those live at the beginning.
1988 LOCAL_SET, if non-null, will be set with all registers killed
1989 unconditionally by this basic block.
1990 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1991 killed conditionally by this basic block. If there is any unconditional
1992 set of a register, then the corresponding bit will be set in LOCAL_SET
1993 and cleared in COND_LOCAL_SET.
1994 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1995 case, the resulting set will be equal to the union of the two sets that
1996 would otherwise be computed.
1998 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2001 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2005 regset cond_local_set
;
2008 struct propagate_block_info
*pbi
;
2012 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2014 if (flags
& PROP_REG_INFO
)
2018 /* Process the regs live at the end of the block.
2019 Mark them as not local to any one basic block. */
2020 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2021 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2024 /* Scan the block an insn at a time from end to beginning. */
2027 for (insn
= bb
->end
;; insn
= prev
)
2029 /* If this is a call to `setjmp' et al, warn if any
2030 non-volatile datum is live. */
2031 if ((flags
& PROP_REG_INFO
)
2032 && GET_CODE (insn
) == CALL_INSN
2033 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2034 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2036 prev
= propagate_one_insn (pbi
, insn
);
2037 changed
|= NEXT_INSN (prev
) != insn
;
2039 if (insn
== bb
->head
)
2043 free_propagate_block_info (pbi
);
2048 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2049 (SET expressions whose destinations are registers dead after the insn).
2050 NEEDED is the regset that says which regs are alive after the insn.
2052 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2054 If X is the entire body of an insn, NOTES contains the reg notes
2055 pertaining to the insn. */
2058 insn_dead_p (pbi
, x
, call_ok
, notes
)
2059 struct propagate_block_info
*pbi
;
2062 rtx notes ATTRIBUTE_UNUSED
;
2064 enum rtx_code code
= GET_CODE (x
);
2067 /* As flow is invoked after combine, we must take existing AUTO_INC
2068 expressions into account. */
2069 for (; notes
; notes
= XEXP (notes
, 1))
2071 if (REG_NOTE_KIND (notes
) == REG_INC
)
2073 int regno
= REGNO (XEXP (notes
, 0));
2075 /* Don't delete insns to set global regs. */
2076 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2077 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2083 /* If setting something that's a reg or part of one,
2084 see if that register's altered value will be live. */
2088 rtx r
= SET_DEST (x
);
2091 if (GET_CODE (r
) == CC0
)
2092 return ! pbi
->cc0_live
;
2095 /* A SET that is a subroutine call cannot be dead. */
2096 if (GET_CODE (SET_SRC (x
)) == CALL
)
2102 /* Don't eliminate loads from volatile memory or volatile asms. */
2103 else if (volatile_refs_p (SET_SRC (x
)))
2106 if (GET_CODE (r
) == MEM
)
2110 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2113 canon_r
= canon_rtx (r
);
2115 /* Walk the set of memory locations we are currently tracking
2116 and see if one is an identical match to this memory location.
2117 If so, this memory write is dead (remember, we're walking
2118 backwards from the end of the block to the start). Since
2119 rtx_equal_p does not check the alias set or flags, we also
2120 must have the potential for them to conflict (anti_dependence). */
2121 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2122 if (anti_dependence (r
, XEXP (temp
, 0)))
2124 rtx mem
= XEXP (temp
, 0);
2126 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2127 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2128 <= GET_MODE_SIZE (GET_MODE (mem
))))
2132 /* Check if memory reference matches an auto increment. Only
2133 post increment/decrement or modify are valid. */
2134 if (GET_MODE (mem
) == GET_MODE (r
)
2135 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2136 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2137 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2138 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2139 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2146 while (GET_CODE (r
) == SUBREG
2147 || GET_CODE (r
) == STRICT_LOW_PART
2148 || GET_CODE (r
) == ZERO_EXTRACT
)
2151 if (GET_CODE (r
) == REG
)
2153 int regno
= REGNO (r
);
2156 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2159 /* If this is a hard register, verify that subsequent
2160 words are not needed. */
2161 if (regno
< FIRST_PSEUDO_REGISTER
)
2163 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2166 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2170 /* Don't delete insns to set global regs. */
2171 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2174 /* Make sure insns to set the stack pointer aren't deleted. */
2175 if (regno
== STACK_POINTER_REGNUM
)
2178 /* ??? These bits might be redundant with the force live bits
2179 in calculate_global_regs_live. We would delete from
2180 sequential sets; whether this actually affects real code
2181 for anything but the stack pointer I don't know. */
2182 /* Make sure insns to set the frame pointer aren't deleted. */
2183 if (regno
== FRAME_POINTER_REGNUM
2184 && (! reload_completed
|| frame_pointer_needed
))
2186 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2187 if (regno
== HARD_FRAME_POINTER_REGNUM
2188 && (! reload_completed
|| frame_pointer_needed
))
2192 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2193 /* Make sure insns to set arg pointer are never deleted
2194 (if the arg pointer isn't fixed, there will be a USE
2195 for it, so we can treat it normally). */
2196 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2200 /* Otherwise, the set is dead. */
2206 /* If performing several activities, insn is dead if each activity
2207 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2208 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2210 else if (code
== PARALLEL
)
2212 int i
= XVECLEN (x
, 0);
2214 for (i
--; i
>= 0; i
--)
2215 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2216 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2217 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2223 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2224 is not necessarily true for hard registers. */
2225 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2226 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2227 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2230 /* We do not check other CLOBBER or USE here. An insn consisting of just
2231 a CLOBBER or just a USE should not be deleted. */
2235 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2236 return 1 if the entire library call is dead.
2237 This is true if INSN copies a register (hard or pseudo)
2238 and if the hard return reg of the call insn is dead.
2239 (The caller should have tested the destination of the SET inside
2240 INSN already for death.)
2242 If this insn doesn't just copy a register, then we don't
2243 have an ordinary libcall. In that case, cse could not have
2244 managed to substitute the source for the dest later on,
2245 so we can assume the libcall is dead.
2247 PBI is the block info giving pseudoregs live before this insn.
2248 NOTE is the REG_RETVAL note of the insn. */
2251 libcall_dead_p (pbi
, note
, insn
)
2252 struct propagate_block_info
*pbi
;
2256 rtx x
= single_set (insn
);
2260 rtx r
= SET_SRC (x
);
2262 if (GET_CODE (r
) == REG
)
2264 rtx call
= XEXP (note
, 0);
2268 /* Find the call insn. */
2269 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2270 call
= NEXT_INSN (call
);
2272 /* If there is none, do nothing special,
2273 since ordinary death handling can understand these insns. */
2277 /* See if the hard reg holding the value is dead.
2278 If this is a PARALLEL, find the call within it. */
2279 call_pat
= PATTERN (call
);
2280 if (GET_CODE (call_pat
) == PARALLEL
)
2282 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2283 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2284 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2287 /* This may be a library call that is returning a value
2288 via invisible pointer. Do nothing special, since
2289 ordinary death handling can understand these insns. */
2293 call_pat
= XVECEXP (call_pat
, 0, i
);
2296 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2302 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2303 live at function entry. Don't count global register variables, variables
2304 in registers that can be used for function arg passing, or variables in
2305 fixed hard registers. */
2308 regno_uninitialized (regno
)
2311 if (n_basic_blocks
== 0
2312 || (regno
< FIRST_PSEUDO_REGISTER
2313 && (global_regs
[regno
]
2314 || fixed_regs
[regno
]
2315 || FUNCTION_ARG_REGNO_P (regno
))))
2318 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2321 /* 1 if register REGNO was alive at a place where `setjmp' was called
2322 and was set more than once or is an argument.
2323 Such regs may be clobbered by `longjmp'. */
2326 regno_clobbered_at_setjmp (regno
)
2329 if (n_basic_blocks
== 0)
2332 return ((REG_N_SETS (regno
) > 1
2333 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2334 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2337 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2338 maximal list size; look for overlaps in mode and select the largest. */
2340 add_to_mem_set_list (pbi
, mem
)
2341 struct propagate_block_info
*pbi
;
2346 /* We don't know how large a BLKmode store is, so we must not
2347 take them into consideration. */
2348 if (GET_MODE (mem
) == BLKmode
)
2351 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2353 rtx e
= XEXP (i
, 0);
2354 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2356 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2359 /* If we must store a copy of the mem, we can just modify
2360 the mode of the stored copy. */
2361 if (pbi
->flags
& PROP_AUTOINC
)
2362 PUT_MODE (e
, GET_MODE (mem
));
2371 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2374 /* Store a copy of mem, otherwise the address may be
2375 scrogged by find_auto_inc. */
2376 if (pbi
->flags
& PROP_AUTOINC
)
2377 mem
= shallow_copy_rtx (mem
);
2379 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2380 pbi
->mem_set_list_len
++;
2384 /* INSN references memory, possibly using autoincrement addressing modes.
2385 Find any entries on the mem_set_list that need to be invalidated due
2386 to an address change. */
2389 invalidate_mems_from_autoinc (px
, data
)
2394 struct propagate_block_info
*pbi
= data
;
2396 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2398 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2405 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2408 invalidate_mems_from_set (pbi
, exp
)
2409 struct propagate_block_info
*pbi
;
2412 rtx temp
= pbi
->mem_set_list
;
2413 rtx prev
= NULL_RTX
;
2418 next
= XEXP (temp
, 1);
2419 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2421 /* Splice this entry out of the list. */
2423 XEXP (prev
, 1) = next
;
2425 pbi
->mem_set_list
= next
;
2426 free_EXPR_LIST_node (temp
);
2427 pbi
->mem_set_list_len
--;
2435 /* Process the registers that are set within X. Their bits are set to
2436 1 in the regset DEAD, because they are dead prior to this insn.
2438 If INSN is nonzero, it is the insn being processed.
2440 FLAGS is the set of operations to perform. */
2443 mark_set_regs (pbi
, x
, insn
)
2444 struct propagate_block_info
*pbi
;
2447 rtx cond
= NULL_RTX
;
2452 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2454 if (REG_NOTE_KIND (link
) == REG_INC
)
2455 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2456 (GET_CODE (x
) == COND_EXEC
2457 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2461 switch (code
= GET_CODE (x
))
2465 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2469 cond
= COND_EXEC_TEST (x
);
2470 x
= COND_EXEC_CODE (x
);
2477 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2479 rtx sub
= XVECEXP (x
, 0, i
);
2480 switch (code
= GET_CODE (sub
))
2483 if (cond
!= NULL_RTX
)
2486 cond
= COND_EXEC_TEST (sub
);
2487 sub
= COND_EXEC_CODE (sub
);
2488 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2494 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2509 /* Process a single set, which appears in INSN. REG (which may not
2510 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2511 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2512 If the set is conditional (because it appear in a COND_EXEC), COND
2513 will be the condition. */
2516 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2517 struct propagate_block_info
*pbi
;
2519 rtx reg
, cond
, insn
;
2522 int regno_first
= -1, regno_last
= -1;
2523 unsigned long not_dead
= 0;
2526 /* Modifying just one hardware register of a multi-reg value or just a
2527 byte field of a register does not mean the value from before this insn
2528 is now dead. Of course, if it was dead after it's unused now. */
2530 switch (GET_CODE (reg
))
2533 /* Some targets place small structures in registers for return values of
2534 functions. We have to detect this case specially here to get correct
2535 flow information. */
2536 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2537 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2538 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2544 case STRICT_LOW_PART
:
2545 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2547 reg
= XEXP (reg
, 0);
2548 while (GET_CODE (reg
) == SUBREG
2549 || GET_CODE (reg
) == ZERO_EXTRACT
2550 || GET_CODE (reg
) == SIGN_EXTRACT
2551 || GET_CODE (reg
) == STRICT_LOW_PART
);
2552 if (GET_CODE (reg
) == MEM
)
2554 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2558 regno_last
= regno_first
= REGNO (reg
);
2559 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2560 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2564 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2566 enum machine_mode outer_mode
= GET_MODE (reg
);
2567 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2569 /* Identify the range of registers affected. This is moderately
2570 tricky for hard registers. See alter_subreg. */
2572 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2573 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2575 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2578 regno_last
= (regno_first
2579 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2581 /* Since we've just adjusted the register number ranges, make
2582 sure REG matches. Otherwise some_was_live will be clear
2583 when it shouldn't have been, and we'll create incorrect
2584 REG_UNUSED notes. */
2585 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2589 /* If the number of words in the subreg is less than the number
2590 of words in the full register, we have a well-defined partial
2591 set. Otherwise the high bits are undefined.
2593 This is only really applicable to pseudos, since we just took
2594 care of multi-word hard registers. */
2595 if (((GET_MODE_SIZE (outer_mode
)
2596 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2597 < ((GET_MODE_SIZE (inner_mode
)
2598 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2599 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2602 reg
= SUBREG_REG (reg
);
2606 reg
= SUBREG_REG (reg
);
2613 /* If this set is a MEM, then it kills any aliased writes.
2614 If this set is a REG, then it kills any MEMs which use the reg. */
2615 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2617 if (GET_CODE (reg
) == REG
)
2618 invalidate_mems_from_set (pbi
, reg
);
2620 /* If the memory reference had embedded side effects (autoincrement
2621 address modes. Then we may need to kill some entries on the
2623 if (insn
&& GET_CODE (reg
) == MEM
)
2624 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2626 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2627 /* ??? With more effort we could track conditional memory life. */
2629 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2632 if (GET_CODE (reg
) == REG
2633 && ! (regno_first
== FRAME_POINTER_REGNUM
2634 && (! reload_completed
|| frame_pointer_needed
))
2635 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2636 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2637 && (! reload_completed
|| frame_pointer_needed
))
2639 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2640 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2644 int some_was_live
= 0, some_was_dead
= 0;
2646 for (i
= regno_first
; i
<= regno_last
; ++i
)
2648 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2651 /* Order of the set operation matters here since both
2652 sets may be the same. */
2653 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2654 if (cond
!= NULL_RTX
2655 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2656 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2658 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2660 if (code
!= CLOBBER
)
2661 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2663 some_was_live
|= needed_regno
;
2664 some_was_dead
|= ! needed_regno
;
2667 #ifdef HAVE_conditional_execution
2668 /* Consider conditional death in deciding that the register needs
2670 if (some_was_live
&& ! not_dead
2671 /* The stack pointer is never dead. Well, not strictly true,
2672 but it's very difficult to tell from here. Hopefully
2673 combine_stack_adjustments will fix up the most egregious
2675 && regno_first
!= STACK_POINTER_REGNUM
)
2677 for (i
= regno_first
; i
<= regno_last
; ++i
)
2678 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2679 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2683 /* Additional data to record if this is the final pass. */
2684 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2685 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2688 int blocknum
= pbi
->bb
->index
;
2691 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2693 y
= pbi
->reg_next_use
[regno_first
];
2695 /* The next use is no longer next, since a store intervenes. */
2696 for (i
= regno_first
; i
<= regno_last
; ++i
)
2697 pbi
->reg_next_use
[i
] = 0;
2700 if (flags
& PROP_REG_INFO
)
2702 for (i
= regno_first
; i
<= regno_last
; ++i
)
2704 /* Count (weighted) references, stores, etc. This counts a
2705 register twice if it is modified, but that is correct. */
2706 REG_N_SETS (i
) += 1;
2707 REG_N_REFS (i
) += 1;
2708 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2710 /* The insns where a reg is live are normally counted
2711 elsewhere, but we want the count to include the insn
2712 where the reg is set, and the normal counting mechanism
2713 would not count it. */
2714 REG_LIVE_LENGTH (i
) += 1;
2717 /* If this is a hard reg, record this function uses the reg. */
2718 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2720 for (i
= regno_first
; i
<= regno_last
; i
++)
2721 regs_ever_live
[i
] = 1;
2725 /* Keep track of which basic blocks each reg appears in. */
2726 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2727 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2728 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2729 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2733 if (! some_was_dead
)
2735 if (flags
& PROP_LOG_LINKS
)
2737 /* Make a logical link from the next following insn
2738 that uses this register, back to this insn.
2739 The following insns have already been processed.
2741 We don't build a LOG_LINK for hard registers containing
2742 in ASM_OPERANDs. If these registers get replaced,
2743 we might wind up changing the semantics of the insn,
2744 even if reload can make what appear to be valid
2745 assignments later. */
2746 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2747 && (regno_first
>= FIRST_PSEUDO_REGISTER
2748 || asm_noperands (PATTERN (y
)) < 0))
2749 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2754 else if (! some_was_live
)
2756 if (flags
& PROP_REG_INFO
)
2757 REG_N_DEATHS (regno_first
) += 1;
2759 if (flags
& PROP_DEATH_NOTES
)
2761 /* Note that dead stores have already been deleted
2762 when possible. If we get here, we have found a
2763 dead store that cannot be eliminated (because the
2764 same insn does something useful). Indicate this
2765 by marking the reg being set as dying here. */
2767 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2772 if (flags
& PROP_DEATH_NOTES
)
2774 /* This is a case where we have a multi-word hard register
2775 and some, but not all, of the words of the register are
2776 needed in subsequent insns. Write REG_UNUSED notes
2777 for those parts that were not needed. This case should
2780 for (i
= regno_first
; i
<= regno_last
; ++i
)
2781 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2783 = alloc_EXPR_LIST (REG_UNUSED
,
2784 gen_rtx_REG (reg_raw_mode
[i
], i
),
2790 /* Mark the register as being dead. */
2792 /* The stack pointer is never dead. Well, not strictly true,
2793 but it's very difficult to tell from here. Hopefully
2794 combine_stack_adjustments will fix up the most egregious
2796 && regno_first
!= STACK_POINTER_REGNUM
)
2798 for (i
= regno_first
; i
<= regno_last
; ++i
)
2799 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2800 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2803 else if (GET_CODE (reg
) == REG
)
2805 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2806 pbi
->reg_next_use
[regno_first
] = 0;
2809 /* If this is the last pass and this is a SCRATCH, show it will be dying
2810 here and count it. */
2811 else if (GET_CODE (reg
) == SCRATCH
)
2813 if (flags
& PROP_DEATH_NOTES
)
2815 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2819 #ifdef HAVE_conditional_execution
2820 /* Mark REGNO conditionally dead.
2821 Return true if the register is now unconditionally dead. */
2824 mark_regno_cond_dead (pbi
, regno
, cond
)
2825 struct propagate_block_info
*pbi
;
2829 /* If this is a store to a predicate register, the value of the
2830 predicate is changing, we don't know that the predicate as seen
2831 before is the same as that seen after. Flush all dependent
2832 conditions from reg_cond_dead. This will make all such
2833 conditionally live registers unconditionally live. */
2834 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2835 flush_reg_cond_reg (pbi
, regno
);
2837 /* If this is an unconditional store, remove any conditional
2838 life that may have existed. */
2839 if (cond
== NULL_RTX
)
2840 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2843 splay_tree_node node
;
2844 struct reg_cond_life_info
*rcli
;
2847 /* Otherwise this is a conditional set. Record that fact.
2848 It may have been conditionally used, or there may be a
2849 subsequent set with a complimentary condition. */
2851 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2854 /* The register was unconditionally live previously.
2855 Record the current condition as the condition under
2856 which it is dead. */
2857 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2858 rcli
->condition
= cond
;
2859 rcli
->stores
= cond
;
2860 rcli
->orig_condition
= const0_rtx
;
2861 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2862 (splay_tree_value
) rcli
);
2864 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2866 /* Not unconditionally dead. */
2871 /* The register was conditionally live previously.
2872 Add the new condition to the old. */
2873 rcli
= (struct reg_cond_life_info
*) node
->value
;
2874 ncond
= rcli
->condition
;
2875 ncond
= ior_reg_cond (ncond
, cond
, 1);
2876 if (rcli
->stores
== const0_rtx
)
2877 rcli
->stores
= cond
;
2878 else if (rcli
->stores
!= const1_rtx
)
2879 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2881 /* If the register is now unconditionally dead, remove the entry
2882 in the splay_tree. A register is unconditionally dead if the
2883 dead condition ncond is true. A register is also unconditionally
2884 dead if the sum of all conditional stores is an unconditional
2885 store (stores is true), and the dead condition is identically the
2886 same as the original dead condition initialized at the end of
2887 the block. This is a pointer compare, not an rtx_equal_p
2889 if (ncond
== const1_rtx
2890 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2891 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2894 rcli
->condition
= ncond
;
2896 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2898 /* Not unconditionally dead. */
2907 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2910 free_reg_cond_life_info (value
)
2911 splay_tree_value value
;
2913 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2917 /* Helper function for flush_reg_cond_reg. */
2920 flush_reg_cond_reg_1 (node
, data
)
2921 splay_tree_node node
;
2924 struct reg_cond_life_info
*rcli
;
2925 int *xdata
= (int *) data
;
2926 unsigned int regno
= xdata
[0];
2928 /* Don't need to search if last flushed value was farther on in
2929 the in-order traversal. */
2930 if (xdata
[1] >= (int) node
->key
)
2933 /* Splice out portions of the expression that refer to regno. */
2934 rcli
= (struct reg_cond_life_info
*) node
->value
;
2935 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2936 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2937 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2939 /* If the entire condition is now false, signal the node to be removed. */
2940 if (rcli
->condition
== const0_rtx
)
2942 xdata
[1] = node
->key
;
2945 else if (rcli
->condition
== const1_rtx
)
2951 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2954 flush_reg_cond_reg (pbi
, regno
)
2955 struct propagate_block_info
*pbi
;
2962 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2963 flush_reg_cond_reg_1
, pair
) == -1)
2964 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
2966 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
2969 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2970 For ior/and, the ADD flag determines whether we want to add the new
2971 condition X to the old one unconditionally. If it is zero, we will
2972 only return a new expression if X allows us to simplify part of
2973 OLD, otherwise we return NULL to the caller.
2974 If ADD is nonzero, we will return a new condition in all cases. The
2975 toplevel caller of one of these functions should always pass 1 for
2979 ior_reg_cond (old
, x
, add
)
2985 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
2987 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
2988 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
2989 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2991 if (GET_CODE (x
) == GET_CODE (old
)
2992 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2996 return gen_rtx_IOR (0, old
, x
);
2999 switch (GET_CODE (old
))
3002 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3003 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3004 if (op0
!= NULL
|| op1
!= NULL
)
3006 if (op0
== const0_rtx
)
3007 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3008 if (op1
== const0_rtx
)
3009 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3010 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3013 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3014 else if (rtx_equal_p (x
, op0
))
3015 /* (x | A) | x ~ (x | A). */
3018 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3019 else if (rtx_equal_p (x
, op1
))
3020 /* (A | x) | x ~ (A | x). */
3022 return gen_rtx_IOR (0, op0
, op1
);
3026 return gen_rtx_IOR (0, old
, x
);
3029 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3030 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3031 if (op0
!= NULL
|| op1
!= NULL
)
3033 if (op0
== const1_rtx
)
3034 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3035 if (op1
== const1_rtx
)
3036 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3037 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3040 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3041 else if (rtx_equal_p (x
, op0
))
3042 /* (x & A) | x ~ x. */
3045 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3046 else if (rtx_equal_p (x
, op1
))
3047 /* (A & x) | x ~ x. */
3049 return gen_rtx_AND (0, op0
, op1
);
3053 return gen_rtx_IOR (0, old
, x
);
3056 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3058 return not_reg_cond (op0
);
3061 return gen_rtx_IOR (0, old
, x
);
3072 enum rtx_code x_code
;
3074 if (x
== const0_rtx
)
3076 else if (x
== const1_rtx
)
3078 x_code
= GET_CODE (x
);
3081 if (GET_RTX_CLASS (x_code
) == '<'
3082 && GET_CODE (XEXP (x
, 0)) == REG
)
3084 if (XEXP (x
, 1) != const0_rtx
)
3087 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3088 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3090 return gen_rtx_NOT (0, x
);
3094 and_reg_cond (old
, x
, add
)
3100 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3102 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3103 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3104 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3106 if (GET_CODE (x
) == GET_CODE (old
)
3107 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3111 return gen_rtx_AND (0, old
, x
);
3114 switch (GET_CODE (old
))
3117 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3118 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3119 if (op0
!= NULL
|| op1
!= NULL
)
3121 if (op0
== const0_rtx
)
3122 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3123 if (op1
== const0_rtx
)
3124 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3125 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3128 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3129 else if (rtx_equal_p (x
, op0
))
3130 /* (x | A) & x ~ x. */
3133 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3134 else if (rtx_equal_p (x
, op1
))
3135 /* (A | x) & x ~ x. */
3137 return gen_rtx_IOR (0, op0
, op1
);
3141 return gen_rtx_AND (0, old
, x
);
3144 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3145 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3146 if (op0
!= NULL
|| op1
!= NULL
)
3148 if (op0
== const1_rtx
)
3149 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3150 if (op1
== const1_rtx
)
3151 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3152 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3155 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3156 else if (rtx_equal_p (x
, op0
))
3157 /* (x & A) & x ~ (x & A). */
3160 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3161 else if (rtx_equal_p (x
, op1
))
3162 /* (A & x) & x ~ (A & x). */
3164 return gen_rtx_AND (0, op0
, op1
);
3168 return gen_rtx_AND (0, old
, x
);
3171 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3173 return not_reg_cond (op0
);
3176 return gen_rtx_AND (0, old
, x
);
3183 /* Given a condition X, remove references to reg REGNO and return the
3184 new condition. The removal will be done so that all conditions
3185 involving REGNO are considered to evaluate to false. This function
3186 is used when the value of REGNO changes. */
3189 elim_reg_cond (x
, regno
)
3195 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3197 if (REGNO (XEXP (x
, 0)) == regno
)
3202 switch (GET_CODE (x
))
3205 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3206 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3207 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3209 if (op0
== const1_rtx
)
3211 if (op1
== const1_rtx
)
3213 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3215 return gen_rtx_AND (0, op0
, op1
);
3218 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3219 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3220 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3222 if (op0
== const0_rtx
)
3224 if (op1
== const0_rtx
)
3226 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3228 return gen_rtx_IOR (0, op0
, op1
);
3231 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3232 if (op0
== const0_rtx
)
3234 if (op0
== const1_rtx
)
3236 if (op0
!= XEXP (x
, 0))
3237 return not_reg_cond (op0
);
3244 #endif /* HAVE_conditional_execution */
3248 /* Try to substitute the auto-inc expression INC as the address inside
3249 MEM which occurs in INSN. Currently, the address of MEM is an expression
3250 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3251 that has a single set whose source is a PLUS of INCR_REG and something
3255 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3256 struct propagate_block_info
*pbi
;
3257 rtx inc
, insn
, mem
, incr
, incr_reg
;
3259 int regno
= REGNO (incr_reg
);
3260 rtx set
= single_set (incr
);
3261 rtx q
= SET_DEST (set
);
3262 rtx y
= SET_SRC (set
);
3263 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3265 /* Make sure this reg appears only once in this insn. */
3266 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3269 if (dead_or_set_p (incr
, incr_reg
)
3270 /* Mustn't autoinc an eliminable register. */
3271 && (regno
>= FIRST_PSEUDO_REGISTER
3272 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3274 /* This is the simple case. Try to make the auto-inc. If
3275 we can't, we are done. Otherwise, we will do any
3276 needed updates below. */
3277 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3280 else if (GET_CODE (q
) == REG
3281 /* PREV_INSN used here to check the semi-open interval
3283 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3284 /* We must also check for sets of q as q may be
3285 a call clobbered hard register and there may
3286 be a call between PREV_INSN (insn) and incr. */
3287 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3289 /* We have *p followed sometime later by q = p+size.
3290 Both p and q must be live afterward,
3291 and q is not used between INSN and its assignment.
3292 Change it to q = p, ...*q..., q = q+size.
3293 Then fall into the usual case. */
3297 emit_move_insn (q
, incr_reg
);
3298 insns
= get_insns ();
3301 /* If we can't make the auto-inc, or can't make the
3302 replacement into Y, exit. There's no point in making
3303 the change below if we can't do the auto-inc and doing
3304 so is not correct in the pre-inc case. */
3307 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3308 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3309 if (! apply_change_group ())
3312 /* We now know we'll be doing this change, so emit the
3313 new insn(s) and do the updates. */
3314 emit_insns_before (insns
, insn
);
3316 if (pbi
->bb
->head
== insn
)
3317 pbi
->bb
->head
= insns
;
3319 /* INCR will become a NOTE and INSN won't contain a
3320 use of INCR_REG. If a use of INCR_REG was just placed in
3321 the insn before INSN, make that the next use.
3322 Otherwise, invalidate it. */
3323 if (GET_CODE (PREV_INSN (insn
)) == INSN
3324 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3325 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3326 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3328 pbi
->reg_next_use
[regno
] = 0;
3333 /* REGNO is now used in INCR which is below INSN, but
3334 it previously wasn't live here. If we don't mark
3335 it as live, we'll put a REG_DEAD note for it
3336 on this insn, which is incorrect. */
3337 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3339 /* If there are any calls between INSN and INCR, show
3340 that REGNO now crosses them. */
3341 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3342 if (GET_CODE (temp
) == CALL_INSN
)
3343 REG_N_CALLS_CROSSED (regno
)++;
3345 /* Invalidate alias info for Q since we just changed its value. */
3346 clear_reg_alias_info (q
);
3351 /* If we haven't returned, it means we were able to make the
3352 auto-inc, so update the status. First, record that this insn
3353 has an implicit side effect. */
3355 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3357 /* Modify the old increment-insn to simply copy
3358 the already-incremented value of our register. */
3359 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3362 /* If that makes it a no-op (copying the register into itself) delete
3363 it so it won't appear to be a "use" and a "set" of this
3365 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3367 /* If the original source was dead, it's dead now. */
3370 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3372 remove_note (incr
, note
);
3373 if (XEXP (note
, 0) != incr_reg
)
3374 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3377 PUT_CODE (incr
, NOTE
);
3378 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3379 NOTE_SOURCE_FILE (incr
) = 0;
3382 if (regno
>= FIRST_PSEUDO_REGISTER
)
3384 /* Count an extra reference to the reg. When a reg is
3385 incremented, spilling it is worse, so we want to make
3386 that less likely. */
3387 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3389 /* Count the increment as a setting of the register,
3390 even though it isn't a SET in rtl. */
3391 REG_N_SETS (regno
)++;
3395 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3399 find_auto_inc (pbi
, x
, insn
)
3400 struct propagate_block_info
*pbi
;
3404 rtx addr
= XEXP (x
, 0);
3405 HOST_WIDE_INT offset
= 0;
3406 rtx set
, y
, incr
, inc_val
;
3408 int size
= GET_MODE_SIZE (GET_MODE (x
));
3410 if (GET_CODE (insn
) == JUMP_INSN
)
3413 /* Here we detect use of an index register which might be good for
3414 postincrement, postdecrement, preincrement, or predecrement. */
3416 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3417 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3419 if (GET_CODE (addr
) != REG
)
3422 regno
= REGNO (addr
);
3424 /* Is the next use an increment that might make auto-increment? */
3425 incr
= pbi
->reg_next_use
[regno
];
3426 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3428 set
= single_set (incr
);
3429 if (set
== 0 || GET_CODE (set
) != SET
)
3433 if (GET_CODE (y
) != PLUS
)
3436 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3437 inc_val
= XEXP (y
, 1);
3438 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3439 inc_val
= XEXP (y
, 0);
3443 if (GET_CODE (inc_val
) == CONST_INT
)
3445 if (HAVE_POST_INCREMENT
3446 && (INTVAL (inc_val
) == size
&& offset
== 0))
3447 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3449 else if (HAVE_POST_DECREMENT
3450 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3451 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3453 else if (HAVE_PRE_INCREMENT
3454 && (INTVAL (inc_val
) == size
&& offset
== size
))
3455 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3457 else if (HAVE_PRE_DECREMENT
3458 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3459 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3461 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3462 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3463 gen_rtx_PLUS (Pmode
,
3466 insn
, x
, incr
, addr
);
3468 else if (GET_CODE (inc_val
) == REG
3469 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3473 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3474 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3475 gen_rtx_PLUS (Pmode
,
3478 insn
, x
, incr
, addr
);
3482 #endif /* AUTO_INC_DEC */
3485 mark_used_reg (pbi
, reg
, cond
, insn
)
3486 struct propagate_block_info
*pbi
;
3488 rtx cond ATTRIBUTE_UNUSED
;
3491 unsigned int regno_first
, regno_last
, i
;
3492 int some_was_live
, some_was_dead
, some_not_set
;
3494 regno_last
= regno_first
= REGNO (reg
);
3495 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3496 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3498 /* Find out if any of this register is live after this instruction. */
3499 some_was_live
= some_was_dead
= 0;
3500 for (i
= regno_first
; i
<= regno_last
; ++i
)
3502 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3503 some_was_live
|= needed_regno
;
3504 some_was_dead
|= ! needed_regno
;
3507 /* Find out if any of the register was set this insn. */
3509 for (i
= regno_first
; i
<= regno_last
; ++i
)
3510 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3512 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3514 /* Record where each reg is used, so when the reg is set we know
3515 the next insn that uses it. */
3516 pbi
->reg_next_use
[regno_first
] = insn
;
3519 if (pbi
->flags
& PROP_REG_INFO
)
3521 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3523 /* If this is a register we are going to try to eliminate,
3524 don't mark it live here. If we are successful in
3525 eliminating it, it need not be live unless it is used for
3526 pseudos, in which case it will have been set live when it
3527 was allocated to the pseudos. If the register will not
3528 be eliminated, reload will set it live at that point.
3530 Otherwise, record that this function uses this register. */
3531 /* ??? The PPC backend tries to "eliminate" on the pic
3532 register to itself. This should be fixed. In the mean
3533 time, hack around it. */
3535 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3536 && (regno_first
== FRAME_POINTER_REGNUM
3537 || regno_first
== ARG_POINTER_REGNUM
)))
3538 for (i
= regno_first
; i
<= regno_last
; ++i
)
3539 regs_ever_live
[i
] = 1;
3543 /* Keep track of which basic block each reg appears in. */
3545 int blocknum
= pbi
->bb
->index
;
3546 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3547 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3548 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3549 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3551 /* Count (weighted) number of uses of each reg. */
3552 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3553 REG_N_REFS (regno_first
)++;
3557 /* Record and count the insns in which a reg dies. If it is used in
3558 this insn and was dead below the insn then it dies in this insn.
3559 If it was set in this insn, we do not make a REG_DEAD note;
3560 likewise if we already made such a note. */
3561 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3565 /* Check for the case where the register dying partially
3566 overlaps the register set by this insn. */
3567 if (regno_first
!= regno_last
)
3568 for (i
= regno_first
; i
<= regno_last
; ++i
)
3569 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3571 /* If none of the words in X is needed, make a REG_DEAD note.
3572 Otherwise, we must make partial REG_DEAD notes. */
3573 if (! some_was_live
)
3575 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3576 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3578 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3580 if (pbi
->flags
& PROP_REG_INFO
)
3581 REG_N_DEATHS (regno_first
)++;
3585 /* Don't make a REG_DEAD note for a part of a register
3586 that is set in the insn. */
3587 for (i
= regno_first
; i
<= regno_last
; ++i
)
3588 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3589 && ! dead_or_set_regno_p (insn
, i
))
3591 = alloc_EXPR_LIST (REG_DEAD
,
3592 gen_rtx_REG (reg_raw_mode
[i
], i
),
3597 /* Mark the register as being live. */
3598 for (i
= regno_first
; i
<= regno_last
; ++i
)
3600 #ifdef HAVE_conditional_execution
3601 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3604 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3606 #ifdef HAVE_conditional_execution
3607 /* If this is a conditional use, record that fact. If it is later
3608 conditionally set, we'll know to kill the register. */
3609 if (cond
!= NULL_RTX
)
3611 splay_tree_node node
;
3612 struct reg_cond_life_info
*rcli
;
3617 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3620 /* The register was unconditionally live previously.
3621 No need to do anything. */
3625 /* The register was conditionally live previously.
3626 Subtract the new life cond from the old death cond. */
3627 rcli
= (struct reg_cond_life_info
*) node
->value
;
3628 ncond
= rcli
->condition
;
3629 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3631 /* If the register is now unconditionally live,
3632 remove the entry in the splay_tree. */
3633 if (ncond
== const0_rtx
)
3634 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3637 rcli
->condition
= ncond
;
3638 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3639 REGNO (XEXP (cond
, 0)));
3645 /* The register was not previously live at all. Record
3646 the condition under which it is still dead. */
3647 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3648 rcli
->condition
= not_reg_cond (cond
);
3649 rcli
->stores
= const0_rtx
;
3650 rcli
->orig_condition
= const0_rtx
;
3651 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3652 (splay_tree_value
) rcli
);
3654 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3657 else if (this_was_live
)
3659 /* The register may have been conditionally live previously, but
3660 is now unconditionally live. Remove it from the conditionally
3661 dead list, so that a conditional set won't cause us to think
3663 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3669 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3670 This is done assuming the registers needed from X are those that
3671 have 1-bits in PBI->REG_LIVE.
3673 INSN is the containing instruction. If INSN is dead, this function
3677 mark_used_regs (pbi
, x
, cond
, insn
)
3678 struct propagate_block_info
*pbi
;
3683 int flags
= pbi
->flags
;
3688 code
= GET_CODE (x
);
3709 /* If we are clobbering a MEM, mark any registers inside the address
3711 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3712 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3716 /* Don't bother watching stores to mems if this is not the
3717 final pass. We'll not be deleting dead stores this round. */
3718 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3720 /* Invalidate the data for the last MEM stored, but only if MEM is
3721 something that can be stored into. */
3722 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3723 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3724 /* Needn't clear the memory set list. */
3728 rtx temp
= pbi
->mem_set_list
;
3729 rtx prev
= NULL_RTX
;
3734 next
= XEXP (temp
, 1);
3735 if (anti_dependence (XEXP (temp
, 0), x
))
3737 /* Splice temp out of the list. */
3739 XEXP (prev
, 1) = next
;
3741 pbi
->mem_set_list
= next
;
3742 free_EXPR_LIST_node (temp
);
3743 pbi
->mem_set_list_len
--;
3751 /* If the memory reference had embedded side effects (autoincrement
3752 address modes. Then we may need to kill some entries on the
3755 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3759 if (flags
& PROP_AUTOINC
)
3760 find_auto_inc (pbi
, x
, insn
);
3765 #ifdef CLASS_CANNOT_CHANGE_MODE
3766 if (GET_CODE (SUBREG_REG (x
)) == REG
3767 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3768 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3769 GET_MODE (SUBREG_REG (x
))))
3770 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3773 /* While we're here, optimize this case. */
3775 if (GET_CODE (x
) != REG
)
3780 /* See a register other than being set => mark it as needed. */
3781 mark_used_reg (pbi
, x
, cond
, insn
);
3786 rtx testreg
= SET_DEST (x
);
3789 /* If storing into MEM, don't show it as being used. But do
3790 show the address as being used. */
3791 if (GET_CODE (testreg
) == MEM
)
3794 if (flags
& PROP_AUTOINC
)
3795 find_auto_inc (pbi
, testreg
, insn
);
3797 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3798 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3802 /* Storing in STRICT_LOW_PART is like storing in a reg
3803 in that this SET might be dead, so ignore it in TESTREG.
3804 but in some other ways it is like using the reg.
3806 Storing in a SUBREG or a bit field is like storing the entire
3807 register in that if the register's value is not used
3808 then this SET is not needed. */
3809 while (GET_CODE (testreg
) == STRICT_LOW_PART
3810 || GET_CODE (testreg
) == ZERO_EXTRACT
3811 || GET_CODE (testreg
) == SIGN_EXTRACT
3812 || GET_CODE (testreg
) == SUBREG
)
3814 #ifdef CLASS_CANNOT_CHANGE_MODE
3815 if (GET_CODE (testreg
) == SUBREG
3816 && GET_CODE (SUBREG_REG (testreg
)) == REG
3817 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3818 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3819 GET_MODE (testreg
)))
3820 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3823 /* Modifying a single register in an alternate mode
3824 does not use any of the old value. But these other
3825 ways of storing in a register do use the old value. */
3826 if (GET_CODE (testreg
) == SUBREG
3827 && !((REG_BYTES (SUBREG_REG (testreg
))
3828 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3829 > (REG_BYTES (testreg
)
3830 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3835 testreg
= XEXP (testreg
, 0);
3838 /* If this is a store into a register or group of registers,
3839 recursively scan the value being stored. */
3841 if ((GET_CODE (testreg
) == PARALLEL
3842 && GET_MODE (testreg
) == BLKmode
)
3843 || (GET_CODE (testreg
) == REG
3844 && (regno
= REGNO (testreg
),
3845 ! (regno
== FRAME_POINTER_REGNUM
3846 && (! reload_completed
|| frame_pointer_needed
)))
3847 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3848 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3849 && (! reload_completed
|| frame_pointer_needed
))
3851 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3852 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3857 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3858 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3865 case UNSPEC_VOLATILE
:
3869 /* Traditional and volatile asm instructions must be considered to use
3870 and clobber all hard registers, all pseudo-registers and all of
3871 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3873 Consider for instance a volatile asm that changes the fpu rounding
3874 mode. An insn should not be moved across this even if it only uses
3875 pseudo-regs because it might give an incorrectly rounded result.
3877 ?!? Unfortunately, marking all hard registers as live causes massive
3878 problems for the register allocator and marking all pseudos as live
3879 creates mountains of uninitialized variable warnings.
3881 So for now, just clear the memory set list and mark any regs
3882 we can find in ASM_OPERANDS as used. */
3883 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3885 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3886 pbi
->mem_set_list_len
= 0;
3889 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3890 We can not just fall through here since then we would be confused
3891 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3892 traditional asms unlike their normal usage. */
3893 if (code
== ASM_OPERANDS
)
3897 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3898 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3904 if (cond
!= NULL_RTX
)
3907 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3909 cond
= COND_EXEC_TEST (x
);
3910 x
= COND_EXEC_CODE (x
);
3914 /* We _do_not_ want to scan operands of phi nodes. Operands of
3915 a phi function are evaluated only when control reaches this
3916 block along a particular edge. Therefore, regs that appear
3917 as arguments to phi should not be added to the global live at
3925 /* Recursively scan the operands of this expression. */
3928 const char * const fmt
= GET_RTX_FORMAT (code
);
3931 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3935 /* Tail recursive case: save a function call level. */
3941 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3943 else if (fmt
[i
] == 'E')
3946 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3947 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3956 try_pre_increment_1 (pbi
, insn
)
3957 struct propagate_block_info
*pbi
;
3960 /* Find the next use of this reg. If in same basic block,
3961 make it do pre-increment or pre-decrement if appropriate. */
3962 rtx x
= single_set (insn
);
3963 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3964 * INTVAL (XEXP (SET_SRC (x
), 1)));
3965 int regno
= REGNO (SET_DEST (x
));
3966 rtx y
= pbi
->reg_next_use
[regno
];
3968 && SET_DEST (x
) != stack_pointer_rtx
3969 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
3970 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3971 mode would be better. */
3972 && ! dead_or_set_p (y
, SET_DEST (x
))
3973 && try_pre_increment (y
, SET_DEST (x
), amount
))
3975 /* We have found a suitable auto-increment and already changed
3976 insn Y to do it. So flush this increment instruction. */
3977 propagate_block_delete_insn (insn
);
3979 /* Count a reference to this reg for the increment insn we are
3980 deleting. When a reg is incremented, spilling it is worse,
3981 so we want to make that less likely. */
3982 if (regno
>= FIRST_PSEUDO_REGISTER
)
3984 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3985 REG_N_SETS (regno
)++;
3988 /* Flush any remembered memories depending on the value of
3989 the incremented register. */
3990 invalidate_mems_from_set (pbi
, SET_DEST (x
));
3997 /* Try to change INSN so that it does pre-increment or pre-decrement
3998 addressing on register REG in order to add AMOUNT to REG.
3999 AMOUNT is negative for pre-decrement.
4000 Returns 1 if the change could be made.
4001 This checks all about the validity of the result of modifying INSN. */
4004 try_pre_increment (insn
, reg
, amount
)
4006 HOST_WIDE_INT amount
;
4010 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4011 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4013 /* Nonzero if we can try to make a post-increment or post-decrement.
4014 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4015 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4016 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4019 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4022 /* From the sign of increment, see which possibilities are conceivable
4023 on this target machine. */
4024 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4026 if (HAVE_POST_INCREMENT
&& amount
> 0)
4029 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4031 if (HAVE_POST_DECREMENT
&& amount
< 0)
4034 if (! (pre_ok
|| post_ok
))
4037 /* It is not safe to add a side effect to a jump insn
4038 because if the incremented register is spilled and must be reloaded
4039 there would be no way to store the incremented value back in memory. */
4041 if (GET_CODE (insn
) == JUMP_INSN
)
4046 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4047 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4049 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4053 if (use
== 0 || use
== (rtx
) (size_t) 1)
4056 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4059 /* See if this combination of instruction and addressing mode exists. */
4060 if (! validate_change (insn
, &XEXP (use
, 0),
4061 gen_rtx_fmt_e (amount
> 0
4062 ? (do_post
? POST_INC
: PRE_INC
)
4063 : (do_post
? POST_DEC
: PRE_DEC
),
4067 /* Record that this insn now has an implicit side effect on X. */
4068 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4072 #endif /* AUTO_INC_DEC */
4074 /* Find the place in the rtx X where REG is used as a memory address.
4075 Return the MEM rtx that so uses it.
4076 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4077 (plus REG (const_int PLUSCONST)).
4079 If such an address does not appear, return 0.
4080 If REG appears more than once, or is used other than in such an address,
4084 find_use_as_address (x
, reg
, plusconst
)
4087 HOST_WIDE_INT plusconst
;
4089 enum rtx_code code
= GET_CODE (x
);
4090 const char * const fmt
= GET_RTX_FORMAT (code
);
4095 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4098 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4099 && XEXP (XEXP (x
, 0), 0) == reg
4100 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4101 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4104 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4106 /* If REG occurs inside a MEM used in a bit-field reference,
4107 that is unacceptable. */
4108 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4109 return (rtx
) (size_t) 1;
4113 return (rtx
) (size_t) 1;
4115 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4119 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4123 return (rtx
) (size_t) 1;
4125 else if (fmt
[i
] == 'E')
4128 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4130 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4134 return (rtx
) (size_t) 1;
4142 /* Write information about registers and basic blocks into FILE.
4143 This is part of making a debugging dump. */
4146 dump_regset (r
, outf
)
4153 fputs (" (nil)", outf
);
4157 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4159 fprintf (outf
, " %d", i
);
4160 if (i
< FIRST_PSEUDO_REGISTER
)
4161 fprintf (outf
, " [%s]",
4166 /* Print a human-reaable representation of R on the standard error
4167 stream. This function is designed to be used from within the
4174 dump_regset (r
, stderr
);
4175 putc ('\n', stderr
);
4178 /* Recompute register set/reference counts immediately prior to register
4181 This avoids problems with set/reference counts changing to/from values
4182 which have special meanings to the register allocators.
4184 Additionally, the reference counts are the primary component used by the
4185 register allocators to prioritize pseudos for allocation to hard regs.
4186 More accurate reference counts generally lead to better register allocation.
4188 F is the first insn to be scanned.
4190 LOOP_STEP denotes how much loop_depth should be incremented per
4191 loop nesting level in order to increase the ref count more for
4192 references in a loop.
4194 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4195 possibly other information which is used by the register allocators. */
4198 recompute_reg_usage (f
, loop_step
)
4199 rtx f ATTRIBUTE_UNUSED
;
4200 int loop_step ATTRIBUTE_UNUSED
;
4202 allocate_reg_life_data ();
4203 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4206 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4207 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4208 of the number of registers that died. */
4211 count_or_remove_death_notes (blocks
, kill
)
4218 FOR_EACH_BB_REVERSE (bb
)
4222 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4225 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4229 rtx
*pprev
= ®_NOTES (insn
);
4234 switch (REG_NOTE_KIND (link
))
4237 if (GET_CODE (XEXP (link
, 0)) == REG
)
4239 rtx reg
= XEXP (link
, 0);
4242 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4245 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4253 rtx next
= XEXP (link
, 1);
4254 free_EXPR_LIST_node (link
);
4255 *pprev
= link
= next
;
4261 pprev
= &XEXP (link
, 1);
4268 if (insn
== bb
->end
)
4275 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4276 if blocks is NULL. */
4279 clear_log_links (blocks
)
4287 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4289 free_INSN_LIST_list (&LOG_LINKS (insn
));
4292 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4294 basic_block bb
= BASIC_BLOCK (i
);
4296 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4297 insn
= NEXT_INSN (insn
))
4299 free_INSN_LIST_list (&LOG_LINKS (insn
));
4303 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4304 correspond to the hard registers, if any, set in that map. This
4305 could be done far more efficiently by having all sorts of special-cases
4306 with moving single words, but probably isn't worth the trouble. */
4309 reg_set_to_hard_reg_set (to
, from
)
4315 EXECUTE_IF_SET_IN_BITMAP
4318 if (i
>= FIRST_PSEUDO_REGISTER
)
4320 SET_HARD_REG_BIT (*to
, i
);