1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 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 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* Nonzero if the second flow pass has completed. */
180 /* Maximum register number used in this function, plus one. */
184 /* Indexed by n, giving various register information */
186 varray_type reg_n_info
;
188 /* Size of a regset for the current function,
189 in (1) bytes and (2) elements. */
194 /* Regset of regs live when calls to `setjmp'-like functions happen. */
195 /* ??? Does this exist only for the setjmp-clobbered warning message? */
197 regset regs_live_at_setjmp
;
199 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
200 that have to go in the same hard reg.
201 The first two regs in the list are a pair, and the next two
202 are another pair, etc. */
205 /* Callback that determines if it's ok for a function to have no
206 noreturn attribute. */
207 int (*lang_missing_noreturn_ok_p
) PARAMS ((tree
));
209 /* Set of registers that may be eliminable. These are handled specially
210 in updating regs_ever_live. */
212 static HARD_REG_SET elim_reg_set
;
214 /* Holds information for tracking conditional register life information. */
215 struct reg_cond_life_info
217 /* A boolean expression of conditions under which a register is dead. */
219 /* Conditions under which a register is dead at the basic block end. */
222 /* A boolean expression of conditions under which a register has been
226 /* ??? Could store mask of bytes that are dead, so that we could finally
227 track lifetimes of multi-word registers accessed via subregs. */
230 /* For use in communicating between propagate_block and its subroutines.
231 Holds all information needed to compute life and def-use information. */
233 struct propagate_block_info
235 /* The basic block we're considering. */
238 /* Bit N is set if register N is conditionally or unconditionally live. */
241 /* Bit N is set if register N is set this insn. */
244 /* Element N is the next insn that uses (hard or pseudo) register N
245 within the current basic block; or zero, if there is no such insn. */
248 /* Contains a list of all the MEMs we are tracking for dead store
252 /* If non-null, record the set of registers set unconditionally in the
256 /* If non-null, record the set of registers set conditionally in the
258 regset cond_local_set
;
260 #ifdef HAVE_conditional_execution
261 /* Indexed by register number, holds a reg_cond_life_info for each
262 register that is not unconditionally live or dead. */
263 splay_tree reg_cond_dead
;
265 /* Bit N is set if register N is in an expression in reg_cond_dead. */
269 /* The length of mem_set_list. */
270 int mem_set_list_len
;
272 /* Non-zero if the value of CC0 is live. */
275 /* Flags controling the set of information propagate_block collects. */
279 /* Maximum length of pbi->mem_set_list before we start dropping
280 new elements on the floor. */
281 #define MAX_MEM_SET_LIST_LEN 100
283 /* Have print_rtl_and_abort give the same information that fancy_abort
285 #define print_rtl_and_abort() \
286 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
288 /* Forward declarations */
289 static int verify_wide_reg_1
PARAMS ((rtx
*, void *));
290 static void verify_wide_reg
PARAMS ((int, rtx
, rtx
));
291 static void verify_local_live_at_start
PARAMS ((regset
, basic_block
));
292 static void notice_stack_pointer_modification_1
PARAMS ((rtx
, rtx
, void *));
293 static void notice_stack_pointer_modification
PARAMS ((rtx
));
294 static void mark_reg
PARAMS ((rtx
, void *));
295 static void mark_regs_live_at_end
PARAMS ((regset
));
296 static int set_phi_alternative_reg
PARAMS ((rtx
, int, int, void *));
297 static void calculate_global_regs_live
PARAMS ((sbitmap
, sbitmap
, int));
298 static void propagate_block_delete_insn
PARAMS ((basic_block
, rtx
));
299 static rtx propagate_block_delete_libcall
PARAMS ((rtx
, rtx
));
300 static int insn_dead_p
PARAMS ((struct propagate_block_info
*,
302 static int libcall_dead_p
PARAMS ((struct propagate_block_info
*,
304 static void mark_set_regs
PARAMS ((struct propagate_block_info
*,
306 static void mark_set_1
PARAMS ((struct propagate_block_info
*,
307 enum rtx_code
, rtx
, rtx
,
309 #ifdef HAVE_conditional_execution
310 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
312 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
313 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
314 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
316 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
317 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
318 static rtx not_reg_cond
PARAMS ((rtx
));
319 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
322 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
323 rtx
, rtx
, rtx
, rtx
, rtx
));
324 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
326 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
328 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
330 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
332 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
334 void dump_flow_info
PARAMS ((FILE *));
335 void debug_flow_info
PARAMS ((void));
336 static void print_rtl_and_abort_fcn
PARAMS ((const char *, int,
340 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
342 static void invalidate_mems_from_autoinc
PARAMS ((struct propagate_block_info
*,
344 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
346 static void delete_dead_jumptables
PARAMS ((void));
350 check_function_return_warnings ()
352 if (warn_missing_noreturn
353 && !TREE_THIS_VOLATILE (cfun
->decl
)
354 && EXIT_BLOCK_PTR
->pred
== NULL
355 && (lang_missing_noreturn_ok_p
356 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
357 warning ("function might be possible candidate for attribute `noreturn'");
359 /* If we have a path to EXIT, then we do return. */
360 if (TREE_THIS_VOLATILE (cfun
->decl
)
361 && EXIT_BLOCK_PTR
->pred
!= NULL
)
362 warning ("`noreturn' function does return");
364 /* If the clobber_return_insn appears in some basic block, then we
365 do reach the end without returning a value. */
366 else if (warn_return_type
367 && cfun
->x_clobber_return_insn
!= NULL
368 && EXIT_BLOCK_PTR
->pred
!= NULL
)
370 int max_uid
= get_max_uid ();
372 /* If clobber_return_insn was excised by jump1, then renumber_insns
373 can make max_uid smaller than the number still recorded in our rtx.
374 That's fine, since this is a quick way of verifying that the insn
375 is no longer in the chain. */
376 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
378 /* Recompute insn->block mapping, since the initial mapping is
379 set before we delete unreachable blocks. */
380 if (BLOCK_FOR_INSN (cfun
->x_clobber_return_insn
) != NULL
)
381 warning ("control reaches end of non-void function");
386 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
387 note associated with the BLOCK. */
390 first_insn_after_basic_block_note (block
)
395 /* Get the first instruction in the block. */
398 if (insn
== NULL_RTX
)
400 if (GET_CODE (insn
) == CODE_LABEL
)
401 insn
= NEXT_INSN (insn
);
402 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
405 return NEXT_INSN (insn
);
408 /* Perform data flow analysis.
409 F is the first insn of the function; FLAGS is a set of PROP_* flags
410 to be used in accumulating flow info. */
413 life_analysis (f
, file
, flags
)
418 #ifdef ELIMINABLE_REGS
420 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
423 /* Record which registers will be eliminated. We use this in
426 CLEAR_HARD_REG_SET (elim_reg_set
);
428 #ifdef ELIMINABLE_REGS
429 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
430 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
432 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
436 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
438 /* The post-reload life analysis have (on a global basis) the same
439 registers live as was computed by reload itself. elimination
440 Otherwise offsets and such may be incorrect.
442 Reload will make some registers as live even though they do not
445 We don't want to create new auto-incs after reload, since they
446 are unlikely to be useful and can cause problems with shared
448 if (reload_completed
)
449 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
451 /* We want alias analysis information for local dead store elimination. */
452 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
453 init_alias_analysis ();
455 /* Always remove no-op moves. Do this before other processing so
456 that we don't have to keep re-scanning them. */
457 delete_noop_moves (f
);
459 /* Some targets can emit simpler epilogues if they know that sp was
460 not ever modified during the function. After reload, of course,
461 we've already emitted the epilogue so there's no sense searching. */
462 if (! reload_completed
)
463 notice_stack_pointer_modification (f
);
465 /* Allocate and zero out data structures that will record the
466 data from lifetime analysis. */
467 allocate_reg_life_data ();
468 allocate_bb_life_data ();
470 /* Find the set of registers live on function exit. */
471 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
473 /* "Update" life info from zero. It'd be nice to begin the
474 relaxation with just the exit and noreturn blocks, but that set
475 is not immediately handy. */
477 if (flags
& PROP_REG_INFO
)
478 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
479 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
482 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
483 end_alias_analysis ();
486 dump_flow_info (file
);
488 free_basic_block_vars (1);
490 #ifdef ENABLE_CHECKING
494 /* Search for any REG_LABEL notes which reference deleted labels. */
495 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
497 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
499 if (inote
&& GET_CODE (inote
) == NOTE_INSN_DELETED_LABEL
)
504 /* Removing dead insns should've made jumptables really dead. */
505 delete_dead_jumptables ();
508 /* A subroutine of verify_wide_reg, called through for_each_rtx.
509 Search for REGNO. If found, abort if it is not wider than word_mode. */
512 verify_wide_reg_1 (px
, pregno
)
517 unsigned int regno
= *(int *) pregno
;
519 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
521 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
528 /* A subroutine of verify_local_live_at_start. Search through insns
529 between HEAD and END looking for register REGNO. */
532 verify_wide_reg (regno
, head
, end
)
539 && for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
))
543 head
= NEXT_INSN (head
);
546 /* We didn't find the register at all. Something's way screwy. */
548 fprintf (rtl_dump_file
, "Aborting in verify_wide_reg; reg %d\n", regno
);
549 print_rtl_and_abort ();
552 /* A subroutine of update_life_info. Verify that there are no untoward
553 changes in live_at_start during a local update. */
556 verify_local_live_at_start (new_live_at_start
, bb
)
557 regset new_live_at_start
;
560 if (reload_completed
)
562 /* After reload, there are no pseudos, nor subregs of multi-word
563 registers. The regsets should exactly match. */
564 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
568 fprintf (rtl_dump_file
,
569 "live_at_start mismatch in bb %d, aborting\n",
571 debug_bitmap_file (rtl_dump_file
, bb
->global_live_at_start
);
572 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
574 print_rtl_and_abort ();
581 /* Find the set of changed registers. */
582 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
584 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
586 /* No registers should die. */
587 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
590 fprintf (rtl_dump_file
,
591 "Register %d died unexpectedly in block %d\n", i
,
593 print_rtl_and_abort ();
596 /* Verify that the now-live register is wider than word_mode. */
597 verify_wide_reg (i
, bb
->head
, bb
->end
);
602 /* Updates life information starting with the basic blocks set in BLOCKS.
603 If BLOCKS is null, consider it to be the universal set.
605 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
606 we are only expecting local modifications to basic blocks. If we find
607 extra registers live at the beginning of a block, then we either killed
608 useful data, or we have a broken split that wants data not provided.
609 If we find registers removed from live_at_start, that means we have
610 a broken peephole that is killing a register it shouldn't.
612 ??? This is not true in one situation -- when a pre-reload splitter
613 generates subregs of a multi-word pseudo, current life analysis will
614 lose the kill. So we _can_ have a pseudo go live. How irritating.
616 Including PROP_REG_INFO does not properly refresh regs_ever_live
617 unless the caller resets it to zero. */
620 update_life_info (blocks
, extent
, prop_flags
)
622 enum update_life_extent extent
;
626 regset_head tmp_head
;
629 tmp
= INITIALIZE_REG_SET (tmp_head
);
631 /* Changes to the CFG are only allowed when
632 doing a global update for the entire CFG. */
633 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
634 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
637 /* For a global update, we go through the relaxation process again. */
638 if (extent
!= UPDATE_LIFE_LOCAL
)
644 calculate_global_regs_live (blocks
, blocks
,
645 prop_flags
& (PROP_SCAN_DEAD_CODE
646 | PROP_ALLOW_CFG_CHANGES
));
648 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
649 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
652 /* Removing dead code may allow the CFG to be simplified which
653 in turn may allow for further dead code detection / removal. */
654 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
656 basic_block bb
= BASIC_BLOCK (i
);
658 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
659 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
660 prop_flags
& (PROP_SCAN_DEAD_CODE
661 | PROP_KILL_DEAD_CODE
));
664 if (! changed
|| ! cleanup_cfg (CLEANUP_EXPENSIVE
))
668 /* If asked, remove notes from the blocks we'll update. */
669 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
670 count_or_remove_death_notes (blocks
, 1);
675 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
677 basic_block bb
= BASIC_BLOCK (i
);
679 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
680 propagate_block (bb
, tmp
, NULL
, NULL
, prop_flags
);
682 if (extent
== UPDATE_LIFE_LOCAL
)
683 verify_local_live_at_start (tmp
, bb
);
688 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
690 basic_block bb
= BASIC_BLOCK (i
);
692 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
693 propagate_block (bb
, tmp
, NULL
, NULL
, prop_flags
);
695 if (extent
== UPDATE_LIFE_LOCAL
)
696 verify_local_live_at_start (tmp
, bb
);
702 if (prop_flags
& PROP_REG_INFO
)
704 /* The only pseudos that are live at the beginning of the function
705 are those that were not set anywhere in the function. local-alloc
706 doesn't know how to handle these correctly, so mark them as not
707 local to any one basic block. */
708 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
709 FIRST_PSEUDO_REGISTER
, i
,
710 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
712 /* We have a problem with any pseudoreg that lives across the setjmp.
713 ANSI says that if a user variable does not change in value between
714 the setjmp and the longjmp, then the longjmp preserves it. This
715 includes longjmp from a place where the pseudo appears dead.
716 (In principle, the value still exists if it is in scope.)
717 If the pseudo goes in a hard reg, some other value may occupy
718 that hard reg where this pseudo is dead, thus clobbering the pseudo.
719 Conclusion: such a pseudo must not go in a hard reg. */
720 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
721 FIRST_PSEUDO_REGISTER
, i
,
723 if (regno_reg_rtx
[i
] != 0)
725 REG_LIVE_LENGTH (i
) = -1;
726 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
732 /* Free the variables allocated by find_basic_blocks.
734 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
737 free_basic_block_vars (keep_head_end_p
)
740 if (! keep_head_end_p
)
742 if (basic_block_info
)
745 VARRAY_FREE (basic_block_info
);
749 ENTRY_BLOCK_PTR
->aux
= NULL
;
750 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
751 EXIT_BLOCK_PTR
->aux
= NULL
;
752 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
756 /* Delete any insns that copy a register to itself. */
759 delete_noop_moves (f
)
760 rtx f ATTRIBUTE_UNUSED
;
766 for (i
= 0; i
< n_basic_blocks
; i
++)
768 bb
= BASIC_BLOCK (i
);
769 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
771 next
= NEXT_INSN (insn
);
772 if (INSN_P (insn
) && noop_move_p (insn
))
774 /* Do not call delete_insn here to not confuse backward
775 pointers of LIBCALL block. */
776 PUT_CODE (insn
, NOTE
);
777 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
778 NOTE_SOURCE_FILE (insn
) = 0;
780 purge_dead_edges (bb
);
786 /* Delete any jump tables never referenced. We can't delete them at the
787 time of removing tablejump insn as they are referenced by the preceeding
788 insns computing the destination, so we delay deleting and garbagecollect
789 them once life information is computed. */
791 delete_dead_jumptables ()
794 for (insn
= get_insns (); insn
; insn
= next
)
796 next
= NEXT_INSN (insn
);
797 if (GET_CODE (insn
) == CODE_LABEL
798 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
799 && GET_CODE (next
) == JUMP_INSN
800 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
801 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
804 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
805 delete_insn (NEXT_INSN (insn
));
807 next
= NEXT_INSN (next
);
812 /* Determine if the stack pointer is constant over the life of the function.
813 Only useful before prologues have been emitted. */
816 notice_stack_pointer_modification_1 (x
, pat
, data
)
818 rtx pat ATTRIBUTE_UNUSED
;
819 void *data ATTRIBUTE_UNUSED
;
821 if (x
== stack_pointer_rtx
822 /* The stack pointer is only modified indirectly as the result
823 of a push until later in flow. See the comments in rtl.texi
824 regarding Embedded Side-Effects on Addresses. */
825 || (GET_CODE (x
) == MEM
826 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
827 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
828 current_function_sp_is_unchanging
= 0;
832 notice_stack_pointer_modification (f
)
837 /* Assume that the stack pointer is unchanging if alloca hasn't
839 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
840 if (! current_function_sp_is_unchanging
)
843 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
847 /* Check if insn modifies the stack pointer. */
848 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
850 if (! current_function_sp_is_unchanging
)
856 /* Mark a register in SET. Hard registers in large modes get all
857 of their component registers set as well. */
864 regset set
= (regset
) xset
;
865 int regno
= REGNO (reg
);
867 if (GET_MODE (reg
) == BLKmode
)
870 SET_REGNO_REG_SET (set
, regno
);
871 if (regno
< FIRST_PSEUDO_REGISTER
)
873 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
875 SET_REGNO_REG_SET (set
, regno
+ n
);
879 /* Mark those regs which are needed at the end of the function as live
880 at the end of the last basic block. */
883 mark_regs_live_at_end (set
)
888 /* If exiting needs the right stack value, consider the stack pointer
889 live at the end of the function. */
890 if ((HAVE_epilogue
&& reload_completed
)
891 || ! EXIT_IGNORE_STACK
892 || (! FRAME_POINTER_REQUIRED
893 && ! current_function_calls_alloca
894 && flag_omit_frame_pointer
)
895 || current_function_sp_is_unchanging
)
897 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
900 /* Mark the frame pointer if needed at the end of the function. If
901 we end up eliminating it, it will be removed from the live list
902 of each basic block by reload. */
904 if (! reload_completed
|| frame_pointer_needed
)
906 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
907 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
908 /* If they are different, also mark the hard frame pointer as live. */
909 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
910 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
914 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
915 /* Many architectures have a GP register even without flag_pic.
916 Assume the pic register is not in use, or will be handled by
917 other means, if it is not fixed. */
918 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
919 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
920 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
923 /* Mark all global registers, and all registers used by the epilogue
924 as being live at the end of the function since they may be
925 referenced by our caller. */
926 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
927 if (global_regs
[i
] || EPILOGUE_USES (i
))
928 SET_REGNO_REG_SET (set
, i
);
930 if (HAVE_epilogue
&& reload_completed
)
932 /* Mark all call-saved registers that we actually used. */
933 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
934 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
935 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
936 SET_REGNO_REG_SET (set
, i
);
939 #ifdef EH_RETURN_DATA_REGNO
940 /* Mark the registers that will contain data for the handler. */
941 if (reload_completed
&& current_function_calls_eh_return
)
944 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
945 if (regno
== INVALID_REGNUM
)
947 SET_REGNO_REG_SET (set
, regno
);
950 #ifdef EH_RETURN_STACKADJ_RTX
951 if ((! HAVE_epilogue
|| ! reload_completed
)
952 && current_function_calls_eh_return
)
954 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
955 if (tmp
&& REG_P (tmp
))
959 #ifdef EH_RETURN_HANDLER_RTX
960 if ((! HAVE_epilogue
|| ! reload_completed
)
961 && current_function_calls_eh_return
)
963 rtx tmp
= EH_RETURN_HANDLER_RTX
;
964 if (tmp
&& REG_P (tmp
))
969 /* Mark function return value. */
970 diddle_return_value (mark_reg
, set
);
973 /* Callback function for for_each_successor_phi. DATA is a regset.
974 Sets the SRC_REGNO, the regno of the phi alternative for phi node
975 INSN, in the regset. */
978 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
979 rtx insn ATTRIBUTE_UNUSED
;
980 int dest_regno ATTRIBUTE_UNUSED
;
984 regset live
= (regset
) data
;
985 SET_REGNO_REG_SET (live
, src_regno
);
989 /* Propagate global life info around the graph of basic blocks. Begin
990 considering blocks with their corresponding bit set in BLOCKS_IN.
991 If BLOCKS_IN is null, consider it the universal set.
993 BLOCKS_OUT is set for every block that was changed. */
996 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
997 sbitmap blocks_in
, blocks_out
;
1000 basic_block
*queue
, *qhead
, *qtail
, *qend
;
1001 regset tmp
, new_live_at_end
, call_used
;
1002 regset_head tmp_head
, call_used_head
;
1003 regset_head new_live_at_end_head
;
1006 tmp
= INITIALIZE_REG_SET (tmp_head
);
1007 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1008 call_used
= INITIALIZE_REG_SET (call_used_head
);
1010 /* Inconveniently, this is only redily available in hard reg set form. */
1011 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1012 if (call_used_regs
[i
])
1013 SET_REGNO_REG_SET (call_used
, i
);
1015 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1016 because the `head == tail' style test for an empty queue doesn't
1017 work with a full queue. */
1018 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1020 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1022 /* Queue the blocks set in the initial mask. Do this in reverse block
1023 number order so that we are more likely for the first round to do
1024 useful work. We use AUX non-null to flag that the block is queued. */
1027 /* Clear out the garbage that might be hanging out in bb->aux. */
1028 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1029 BASIC_BLOCK (i
)->aux
= NULL
;
1031 EXECUTE_IF_SET_IN_SBITMAP (blocks_in
, 0, i
,
1033 basic_block bb
= BASIC_BLOCK (i
);
1040 for (i
= 0; i
< n_basic_blocks
; ++i
)
1042 basic_block bb
= BASIC_BLOCK (i
);
1049 sbitmap_zero (blocks_out
);
1051 /* We work through the queue until there are no more blocks. What
1052 is live at the end of this block is precisely the union of what
1053 is live at the beginning of all its successors. So, we set its
1054 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1055 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1056 this block by walking through the instructions in this block in
1057 reverse order and updating as we go. If that changed
1058 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1059 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1061 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1062 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1063 must either be live at the end of the block, or used within the
1064 block. In the latter case, it will certainly never disappear
1065 from GLOBAL_LIVE_AT_START. In the former case, the register
1066 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1067 for one of the successor blocks. By induction, that cannot
1069 while (qhead
!= qtail
)
1071 int rescan
, changed
;
1080 /* Begin by propagating live_at_start from the successor blocks. */
1081 CLEAR_REG_SET (new_live_at_end
);
1082 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1084 basic_block sb
= e
->dest
;
1086 /* Call-clobbered registers die across exception and call edges. */
1087 /* ??? Abnormal call edges ignored for the moment, as this gets
1088 confused by sibling call edges, which crashes reg-stack. */
1089 if (e
->flags
& EDGE_EH
)
1091 bitmap_operation (tmp
, sb
->global_live_at_start
,
1092 call_used
, BITMAP_AND_COMPL
);
1093 IOR_REG_SET (new_live_at_end
, tmp
);
1096 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1099 /* The all-important stack pointer must always be live. */
1100 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1102 /* Before reload, there are a few registers that must be forced
1103 live everywhere -- which might not already be the case for
1104 blocks within infinite loops. */
1105 if (! reload_completed
)
1107 /* Any reference to any pseudo before reload is a potential
1108 reference of the frame pointer. */
1109 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1111 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1112 /* Pseudos with argument area equivalences may require
1113 reloading via the argument pointer. */
1114 if (fixed_regs
[ARG_POINTER_REGNUM
])
1115 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1118 /* Any constant, or pseudo with constant equivalences, may
1119 require reloading from memory using the pic register. */
1120 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1121 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1122 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1125 /* Regs used in phi nodes are not included in
1126 global_live_at_start, since they are live only along a
1127 particular edge. Set those regs that are live because of a
1128 phi node alternative corresponding to this particular block. */
1130 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1133 if (bb
== ENTRY_BLOCK_PTR
)
1135 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1139 /* On our first pass through this block, we'll go ahead and continue.
1140 Recognize first pass by local_set NULL. On subsequent passes, we
1141 get to skip out early if live_at_end wouldn't have changed. */
1143 if (bb
->local_set
== NULL
)
1145 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1146 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1151 /* If any bits were removed from live_at_end, we'll have to
1152 rescan the block. This wouldn't be necessary if we had
1153 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1154 local_live is really dependent on live_at_end. */
1155 CLEAR_REG_SET (tmp
);
1156 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1157 new_live_at_end
, BITMAP_AND_COMPL
);
1161 /* If any of the registers in the new live_at_end set are
1162 conditionally set in this basic block, we must rescan.
1163 This is because conditional lifetimes at the end of the
1164 block do not just take the live_at_end set into account,
1165 but also the liveness at the start of each successor
1166 block. We can miss changes in those sets if we only
1167 compare the new live_at_end against the previous one. */
1168 CLEAR_REG_SET (tmp
);
1169 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1170 bb
->cond_local_set
, BITMAP_AND
);
1175 /* Find the set of changed bits. Take this opportunity
1176 to notice that this set is empty and early out. */
1177 CLEAR_REG_SET (tmp
);
1178 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1179 new_live_at_end
, BITMAP_XOR
);
1183 /* If any of the changed bits overlap with local_set,
1184 we'll have to rescan the block. Detect overlap by
1185 the AND with ~local_set turning off bits. */
1186 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1191 /* Let our caller know that BB changed enough to require its
1192 death notes updated. */
1194 SET_BIT (blocks_out
, bb
->index
);
1198 /* Add to live_at_start the set of all registers in
1199 new_live_at_end that aren't in the old live_at_end. */
1201 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1203 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1205 changed
= bitmap_operation (bb
->global_live_at_start
,
1206 bb
->global_live_at_start
,
1213 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1215 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1216 into live_at_start. */
1217 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1218 bb
->cond_local_set
, flags
);
1220 /* If live_at start didn't change, no need to go farther. */
1221 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1224 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1227 /* Queue all predecessors of BB so that we may re-examine
1228 their live_at_end. */
1229 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1231 basic_block pb
= e
->src
;
1232 if (pb
->aux
== NULL
)
1243 FREE_REG_SET (new_live_at_end
);
1244 FREE_REG_SET (call_used
);
1248 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1250 basic_block bb
= BASIC_BLOCK (i
);
1251 FREE_REG_SET (bb
->local_set
);
1252 FREE_REG_SET (bb
->cond_local_set
);
1257 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1259 basic_block bb
= BASIC_BLOCK (i
);
1260 FREE_REG_SET (bb
->local_set
);
1261 FREE_REG_SET (bb
->cond_local_set
);
1268 /* Subroutines of life analysis. */
1270 /* Allocate the permanent data structures that represent the results
1271 of life analysis. Not static since used also for stupid life analysis. */
1274 allocate_bb_life_data ()
1278 for (i
= 0; i
< n_basic_blocks
; i
++)
1280 basic_block bb
= BASIC_BLOCK (i
);
1282 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1283 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1286 ENTRY_BLOCK_PTR
->global_live_at_end
1287 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1288 EXIT_BLOCK_PTR
->global_live_at_start
1289 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1291 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1295 allocate_reg_life_data ()
1299 max_regno
= max_reg_num ();
1301 /* Recalculate the register space, in case it has grown. Old style
1302 vector oriented regsets would set regset_{size,bytes} here also. */
1303 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1305 /* Reset all the data we'll collect in propagate_block and its
1307 for (i
= 0; i
< max_regno
; i
++)
1311 REG_N_DEATHS (i
) = 0;
1312 REG_N_CALLS_CROSSED (i
) = 0;
1313 REG_LIVE_LENGTH (i
) = 0;
1314 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1318 /* Delete dead instructions for propagate_block. */
1321 propagate_block_delete_insn (bb
, insn
)
1325 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1328 /* If the insn referred to a label, and that label was attached to
1329 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1330 pretty much mandatory to delete it, because the ADDR_VEC may be
1331 referencing labels that no longer exist.
1333 INSN may reference a deleted label, particularly when a jump
1334 table has been optimized into a direct jump. There's no
1335 real good way to fix up the reference to the deleted label
1336 when the label is deleted, so we just allow it here.
1338 After dead code elimination is complete, we do search for
1339 any REG_LABEL notes which reference deleted labels as a
1342 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1344 rtx label
= XEXP (inote
, 0);
1347 /* The label may be forced if it has been put in the constant
1348 pool. If that is the only use we must discard the table
1349 jump following it, but not the label itself. */
1350 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1351 && (next
= next_nonnote_insn (label
)) != NULL
1352 && GET_CODE (next
) == JUMP_INSN
1353 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1354 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1356 rtx pat
= PATTERN (next
);
1357 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1358 int len
= XVECLEN (pat
, diff_vec_p
);
1361 for (i
= 0; i
< len
; i
++)
1362 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1368 if (bb
->end
== insn
)
1372 purge_dead_edges (bb
);
1375 /* Delete dead libcalls for propagate_block. Return the insn
1376 before the libcall. */
1379 propagate_block_delete_libcall ( insn
, note
)
1382 rtx first
= XEXP (note
, 0);
1383 rtx before
= PREV_INSN (first
);
1385 delete_insn_chain (first
, insn
);
1389 /* Update the life-status of regs for one insn. Return the previous insn. */
1392 propagate_one_insn (pbi
, insn
)
1393 struct propagate_block_info
*pbi
;
1396 rtx prev
= PREV_INSN (insn
);
1397 int flags
= pbi
->flags
;
1398 int insn_is_dead
= 0;
1399 int libcall_is_dead
= 0;
1403 if (! INSN_P (insn
))
1406 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1407 if (flags
& PROP_SCAN_DEAD_CODE
)
1409 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1410 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1411 && libcall_dead_p (pbi
, note
, insn
));
1414 /* If an instruction consists of just dead store(s) on final pass,
1416 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1418 /* If we're trying to delete a prologue or epilogue instruction
1419 that isn't flagged as possibly being dead, something is wrong.
1420 But if we are keeping the stack pointer depressed, we might well
1421 be deleting insns that are used to compute the amount to update
1422 it by, so they are fine. */
1423 if (reload_completed
1424 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1425 && (TYPE_RETURNS_STACK_DEPRESSED
1426 (TREE_TYPE (current_function_decl
))))
1427 && (((HAVE_epilogue
|| HAVE_prologue
)
1428 && prologue_epilogue_contains (insn
))
1429 || (HAVE_sibcall_epilogue
1430 && sibcall_epilogue_contains (insn
)))
1431 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1434 /* Record sets. Do this even for dead instructions, since they
1435 would have killed the values if they hadn't been deleted. */
1436 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1438 /* CC0 is now known to be dead. Either this insn used it,
1439 in which case it doesn't anymore, or clobbered it,
1440 so the next insn can't use it. */
1443 if (libcall_is_dead
)
1444 prev
= propagate_block_delete_libcall ( insn
, note
);
1446 propagate_block_delete_insn (pbi
->bb
, insn
);
1451 /* See if this is an increment or decrement that can be merged into
1452 a following memory address. */
1455 register rtx x
= single_set (insn
);
1457 /* Does this instruction increment or decrement a register? */
1458 if ((flags
& PROP_AUTOINC
)
1460 && GET_CODE (SET_DEST (x
)) == REG
1461 && (GET_CODE (SET_SRC (x
)) == PLUS
1462 || GET_CODE (SET_SRC (x
)) == MINUS
)
1463 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1464 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1465 /* Ok, look for a following memory ref we can combine with.
1466 If one is found, change the memory ref to a PRE_INC
1467 or PRE_DEC, cancel this insn, and return 1.
1468 Return 0 if nothing has been done. */
1469 && try_pre_increment_1 (pbi
, insn
))
1472 #endif /* AUTO_INC_DEC */
1474 CLEAR_REG_SET (pbi
->new_set
);
1476 /* If this is not the final pass, and this insn is copying the value of
1477 a library call and it's dead, don't scan the insns that perform the
1478 library call, so that the call's arguments are not marked live. */
1479 if (libcall_is_dead
)
1481 /* Record the death of the dest reg. */
1482 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1484 insn
= XEXP (note
, 0);
1485 return PREV_INSN (insn
);
1487 else if (GET_CODE (PATTERN (insn
)) == SET
1488 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1489 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1490 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1491 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1492 /* We have an insn to pop a constant amount off the stack.
1493 (Such insns use PLUS regardless of the direction of the stack,
1494 and any insn to adjust the stack by a constant is always a pop.)
1495 These insns, if not dead stores, have no effect on life. */
1499 /* Any regs live at the time of a call instruction must not go
1500 in a register clobbered by calls. Find all regs now live and
1501 record this for them. */
1503 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1504 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1505 { REG_N_CALLS_CROSSED (i
)++; });
1507 /* Record sets. Do this even for dead instructions, since they
1508 would have killed the values if they hadn't been deleted. */
1509 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1511 if (GET_CODE (insn
) == CALL_INSN
)
1517 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1518 cond
= COND_EXEC_TEST (PATTERN (insn
));
1520 /* Non-constant calls clobber memory. */
1521 if (! CONST_OR_PURE_CALL_P (insn
))
1523 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1524 pbi
->mem_set_list_len
= 0;
1527 /* There may be extra registers to be clobbered. */
1528 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1530 note
= XEXP (note
, 1))
1531 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1532 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1533 cond
, insn
, pbi
->flags
);
1535 /* Calls change all call-used and global registers. */
1536 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1537 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1539 /* We do not want REG_UNUSED notes for these registers. */
1540 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1542 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1546 /* If an insn doesn't use CC0, it becomes dead since we assume
1547 that every insn clobbers it. So show it dead here;
1548 mark_used_regs will set it live if it is referenced. */
1553 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1555 /* Sometimes we may have inserted something before INSN (such as a move)
1556 when we make an auto-inc. So ensure we will scan those insns. */
1558 prev
= PREV_INSN (insn
);
1561 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1567 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1568 cond
= COND_EXEC_TEST (PATTERN (insn
));
1570 /* Calls use their arguments. */
1571 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1573 note
= XEXP (note
, 1))
1574 if (GET_CODE (XEXP (note
, 0)) == USE
)
1575 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1578 /* The stack ptr is used (honorarily) by a CALL insn. */
1579 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1581 /* Calls may also reference any of the global registers,
1582 so they are made live. */
1583 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1585 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1590 /* On final pass, update counts of how many insns in which each reg
1592 if (flags
& PROP_REG_INFO
)
1593 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1594 { REG_LIVE_LENGTH (i
)++; });
1599 /* Initialize a propagate_block_info struct for public consumption.
1600 Note that the structure itself is opaque to this file, but that
1601 the user can use the regsets provided here. */
1603 struct propagate_block_info
*
1604 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1606 regset live
, local_set
, cond_local_set
;
1609 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1612 pbi
->reg_live
= live
;
1613 pbi
->mem_set_list
= NULL_RTX
;
1614 pbi
->mem_set_list_len
= 0;
1615 pbi
->local_set
= local_set
;
1616 pbi
->cond_local_set
= cond_local_set
;
1620 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1621 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1623 pbi
->reg_next_use
= NULL
;
1625 pbi
->new_set
= BITMAP_XMALLOC ();
1627 #ifdef HAVE_conditional_execution
1628 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1629 free_reg_cond_life_info
);
1630 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1632 /* If this block ends in a conditional branch, for each register live
1633 from one side of the branch and not the other, record the register
1634 as conditionally dead. */
1635 if (GET_CODE (bb
->end
) == JUMP_INSN
1636 && any_condjump_p (bb
->end
))
1638 regset_head diff_head
;
1639 regset diff
= INITIALIZE_REG_SET (diff_head
);
1640 basic_block bb_true
, bb_false
;
1641 rtx cond_true
, cond_false
, set_src
;
1644 /* Identify the successor blocks. */
1645 bb_true
= bb
->succ
->dest
;
1646 if (bb
->succ
->succ_next
!= NULL
)
1648 bb_false
= bb
->succ
->succ_next
->dest
;
1650 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1652 basic_block t
= bb_false
;
1656 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1661 /* This can happen with a conditional jump to the next insn. */
1662 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1665 /* Simplest way to do nothing. */
1669 /* Extract the condition from the branch. */
1670 set_src
= SET_SRC (pc_set (bb
->end
));
1671 cond_true
= XEXP (set_src
, 0);
1672 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1673 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1674 XEXP (cond_true
, 1));
1675 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1678 cond_false
= cond_true
;
1682 /* Compute which register lead different lives in the successors. */
1683 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1684 bb_false
->global_live_at_start
, BITMAP_XOR
))
1686 rtx reg
= XEXP (cond_true
, 0);
1688 if (GET_CODE (reg
) == SUBREG
)
1689 reg
= SUBREG_REG (reg
);
1691 if (GET_CODE (reg
) != REG
)
1694 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1696 /* For each such register, mark it conditionally dead. */
1697 EXECUTE_IF_SET_IN_REG_SET
1700 struct reg_cond_life_info
*rcli
;
1703 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1705 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1709 rcli
->condition
= cond
;
1710 rcli
->stores
= const0_rtx
;
1711 rcli
->orig_condition
= cond
;
1713 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1714 (splay_tree_value
) rcli
);
1718 FREE_REG_SET (diff
);
1722 /* If this block has no successors, any stores to the frame that aren't
1723 used later in the block are dead. So make a pass over the block
1724 recording any such that are made and show them dead at the end. We do
1725 a very conservative and simple job here. */
1727 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1728 && (TYPE_RETURNS_STACK_DEPRESSED
1729 (TREE_TYPE (current_function_decl
))))
1730 && (flags
& PROP_SCAN_DEAD_CODE
)
1731 && (bb
->succ
== NULL
1732 || (bb
->succ
->succ_next
== NULL
1733 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1734 && ! current_function_calls_eh_return
)))
1737 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1738 if (GET_CODE (insn
) == INSN
1739 && (set
= single_set (insn
))
1740 && GET_CODE (SET_DEST (set
)) == MEM
)
1742 rtx mem
= SET_DEST (set
);
1743 rtx canon_mem
= canon_rtx (mem
);
1745 /* This optimization is performed by faking a store to the
1746 memory at the end of the block. This doesn't work for
1747 unchanging memories because multiple stores to unchanging
1748 memory is illegal and alias analysis doesn't consider it. */
1749 if (RTX_UNCHANGING_P (canon_mem
))
1752 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1753 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1754 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1755 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1756 add_to_mem_set_list (pbi
, canon_mem
);
1763 /* Release a propagate_block_info struct. */
1766 free_propagate_block_info (pbi
)
1767 struct propagate_block_info
*pbi
;
1769 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1771 BITMAP_XFREE (pbi
->new_set
);
1773 #ifdef HAVE_conditional_execution
1774 splay_tree_delete (pbi
->reg_cond_dead
);
1775 BITMAP_XFREE (pbi
->reg_cond_reg
);
1778 if (pbi
->reg_next_use
)
1779 free (pbi
->reg_next_use
);
1784 /* Compute the registers live at the beginning of a basic block BB from
1785 those live at the end.
1787 When called, REG_LIVE contains those live at the end. On return, it
1788 contains those live at the beginning.
1790 LOCAL_SET, if non-null, will be set with all registers killed
1791 unconditionally by this basic block.
1792 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1793 killed conditionally by this basic block. If there is any unconditional
1794 set of a register, then the corresponding bit will be set in LOCAL_SET
1795 and cleared in COND_LOCAL_SET.
1796 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1797 case, the resulting set will be equal to the union of the two sets that
1798 would otherwise be computed.
1800 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1803 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
1807 regset cond_local_set
;
1810 struct propagate_block_info
*pbi
;
1814 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
1816 if (flags
& PROP_REG_INFO
)
1820 /* Process the regs live at the end of the block.
1821 Mark them as not local to any one basic block. */
1822 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
1823 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
1826 /* Scan the block an insn at a time from end to beginning. */
1829 for (insn
= bb
->end
;; insn
= prev
)
1831 /* If this is a call to `setjmp' et al, warn if any
1832 non-volatile datum is live. */
1833 if ((flags
& PROP_REG_INFO
)
1834 && GET_CODE (insn
) == CALL_INSN
1835 && find_reg_note (insn
, REG_SETJMP
, NULL
))
1836 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
1838 prev
= propagate_one_insn (pbi
, insn
);
1839 changed
|= NEXT_INSN (prev
) != insn
;
1841 if (insn
== bb
->head
)
1845 free_propagate_block_info (pbi
);
1850 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1851 (SET expressions whose destinations are registers dead after the insn).
1852 NEEDED is the regset that says which regs are alive after the insn.
1854 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1856 If X is the entire body of an insn, NOTES contains the reg notes
1857 pertaining to the insn. */
1860 insn_dead_p (pbi
, x
, call_ok
, notes
)
1861 struct propagate_block_info
*pbi
;
1864 rtx notes ATTRIBUTE_UNUSED
;
1866 enum rtx_code code
= GET_CODE (x
);
1869 /* If flow is invoked after reload, we must take existing AUTO_INC
1870 expresions into account. */
1871 if (reload_completed
)
1873 for (; notes
; notes
= XEXP (notes
, 1))
1875 if (REG_NOTE_KIND (notes
) == REG_INC
)
1877 int regno
= REGNO (XEXP (notes
, 0));
1879 /* Don't delete insns to set global regs. */
1880 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
1881 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
1888 /* If setting something that's a reg or part of one,
1889 see if that register's altered value will be live. */
1893 rtx r
= SET_DEST (x
);
1896 if (GET_CODE (r
) == CC0
)
1897 return ! pbi
->cc0_live
;
1900 /* A SET that is a subroutine call cannot be dead. */
1901 if (GET_CODE (SET_SRC (x
)) == CALL
)
1907 /* Don't eliminate loads from volatile memory or volatile asms. */
1908 else if (volatile_refs_p (SET_SRC (x
)))
1911 if (GET_CODE (r
) == MEM
)
1915 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
1918 canon_r
= canon_rtx (r
);
1920 /* Walk the set of memory locations we are currently tracking
1921 and see if one is an identical match to this memory location.
1922 If so, this memory write is dead (remember, we're walking
1923 backwards from the end of the block to the start). Since
1924 rtx_equal_p does not check the alias set or flags, we also
1925 must have the potential for them to conflict (anti_dependence). */
1926 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
1927 if (anti_dependence (r
, XEXP (temp
, 0)))
1929 rtx mem
= XEXP (temp
, 0);
1931 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
1932 && (GET_MODE_SIZE (GET_MODE (canon_r
))
1933 <= GET_MODE_SIZE (GET_MODE (mem
))))
1937 /* Check if memory reference matches an auto increment. Only
1938 post increment/decrement or modify are valid. */
1939 if (GET_MODE (mem
) == GET_MODE (r
)
1940 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
1941 || GET_CODE (XEXP (mem
, 0)) == POST_INC
1942 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
1943 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
1944 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
1951 while (GET_CODE (r
) == SUBREG
1952 || GET_CODE (r
) == STRICT_LOW_PART
1953 || GET_CODE (r
) == ZERO_EXTRACT
)
1956 if (GET_CODE (r
) == REG
)
1958 int regno
= REGNO (r
);
1961 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
1964 /* If this is a hard register, verify that subsequent
1965 words are not needed. */
1966 if (regno
< FIRST_PSEUDO_REGISTER
)
1968 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
1971 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
1975 /* Don't delete insns to set global regs. */
1976 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
1979 /* Make sure insns to set the stack pointer aren't deleted. */
1980 if (regno
== STACK_POINTER_REGNUM
)
1983 /* ??? These bits might be redundant with the force live bits
1984 in calculate_global_regs_live. We would delete from
1985 sequential sets; whether this actually affects real code
1986 for anything but the stack pointer I don't know. */
1987 /* Make sure insns to set the frame pointer aren't deleted. */
1988 if (regno
== FRAME_POINTER_REGNUM
1989 && (! reload_completed
|| frame_pointer_needed
))
1991 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1992 if (regno
== HARD_FRAME_POINTER_REGNUM
1993 && (! reload_completed
|| frame_pointer_needed
))
1997 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1998 /* Make sure insns to set arg pointer are never deleted
1999 (if the arg pointer isn't fixed, there will be a USE
2000 for it, so we can treat it normally). */
2001 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2005 /* Otherwise, the set is dead. */
2011 /* If performing several activities, insn is dead if each activity
2012 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2013 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2015 else if (code
== PARALLEL
)
2017 int i
= XVECLEN (x
, 0);
2019 for (i
--; i
>= 0; i
--)
2020 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2021 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2022 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2028 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2029 is not necessarily true for hard registers. */
2030 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2031 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2032 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2035 /* We do not check other CLOBBER or USE here. An insn consisting of just
2036 a CLOBBER or just a USE should not be deleted. */
2040 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2041 return 1 if the entire library call is dead.
2042 This is true if INSN copies a register (hard or pseudo)
2043 and if the hard return reg of the call insn is dead.
2044 (The caller should have tested the destination of the SET inside
2045 INSN already for death.)
2047 If this insn doesn't just copy a register, then we don't
2048 have an ordinary libcall. In that case, cse could not have
2049 managed to substitute the source for the dest later on,
2050 so we can assume the libcall is dead.
2052 PBI is the block info giving pseudoregs live before this insn.
2053 NOTE is the REG_RETVAL note of the insn. */
2056 libcall_dead_p (pbi
, note
, insn
)
2057 struct propagate_block_info
*pbi
;
2061 rtx x
= single_set (insn
);
2065 register rtx r
= SET_SRC (x
);
2067 if (GET_CODE (r
) == REG
)
2069 rtx call
= XEXP (note
, 0);
2073 /* Find the call insn. */
2074 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2075 call
= NEXT_INSN (call
);
2077 /* If there is none, do nothing special,
2078 since ordinary death handling can understand these insns. */
2082 /* See if the hard reg holding the value is dead.
2083 If this is a PARALLEL, find the call within it. */
2084 call_pat
= PATTERN (call
);
2085 if (GET_CODE (call_pat
) == PARALLEL
)
2087 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2088 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2089 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2092 /* This may be a library call that is returning a value
2093 via invisible pointer. Do nothing special, since
2094 ordinary death handling can understand these insns. */
2098 call_pat
= XVECEXP (call_pat
, 0, i
);
2101 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2107 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2108 live at function entry. Don't count global register variables, variables
2109 in registers that can be used for function arg passing, or variables in
2110 fixed hard registers. */
2113 regno_uninitialized (regno
)
2116 if (n_basic_blocks
== 0
2117 || (regno
< FIRST_PSEUDO_REGISTER
2118 && (global_regs
[regno
]
2119 || fixed_regs
[regno
]
2120 || FUNCTION_ARG_REGNO_P (regno
))))
2123 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start
, regno
);
2126 /* 1 if register REGNO was alive at a place where `setjmp' was called
2127 and was set more than once or is an argument.
2128 Such regs may be clobbered by `longjmp'. */
2131 regno_clobbered_at_setjmp (regno
)
2134 if (n_basic_blocks
== 0)
2137 return ((REG_N_SETS (regno
) > 1
2138 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start
, regno
))
2139 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2142 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2143 maximal list size; look for overlaps in mode and select the largest. */
2145 add_to_mem_set_list (pbi
, mem
)
2146 struct propagate_block_info
*pbi
;
2151 /* We don't know how large a BLKmode store is, so we must not
2152 take them into consideration. */
2153 if (GET_MODE (mem
) == BLKmode
)
2156 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2158 rtx e
= XEXP (i
, 0);
2159 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2161 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2164 /* If we must store a copy of the mem, we can just modify
2165 the mode of the stored copy. */
2166 if (pbi
->flags
& PROP_AUTOINC
)
2167 PUT_MODE (e
, GET_MODE (mem
));
2176 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2179 /* Store a copy of mem, otherwise the address may be
2180 scrogged by find_auto_inc. */
2181 if (pbi
->flags
& PROP_AUTOINC
)
2182 mem
= shallow_copy_rtx (mem
);
2184 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2185 pbi
->mem_set_list_len
++;
2189 /* INSN references memory, possibly using autoincrement addressing modes.
2190 Find any entries on the mem_set_list that need to be invalidated due
2191 to an address change. */
2194 invalidate_mems_from_autoinc (pbi
, insn
)
2195 struct propagate_block_info
*pbi
;
2198 rtx note
= REG_NOTES (insn
);
2199 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2200 if (REG_NOTE_KIND (note
) == REG_INC
)
2201 invalidate_mems_from_set (pbi
, XEXP (note
, 0));
2204 /* EXP is a REG. Remove any dependant entries from pbi->mem_set_list. */
2207 invalidate_mems_from_set (pbi
, exp
)
2208 struct propagate_block_info
*pbi
;
2211 rtx temp
= pbi
->mem_set_list
;
2212 rtx prev
= NULL_RTX
;
2217 next
= XEXP (temp
, 1);
2218 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2220 /* Splice this entry out of the list. */
2222 XEXP (prev
, 1) = next
;
2224 pbi
->mem_set_list
= next
;
2225 free_EXPR_LIST_node (temp
);
2226 pbi
->mem_set_list_len
--;
2234 /* Process the registers that are set within X. Their bits are set to
2235 1 in the regset DEAD, because they are dead prior to this insn.
2237 If INSN is nonzero, it is the insn being processed.
2239 FLAGS is the set of operations to perform. */
2242 mark_set_regs (pbi
, x
, insn
)
2243 struct propagate_block_info
*pbi
;
2246 rtx cond
= NULL_RTX
;
2251 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2253 if (REG_NOTE_KIND (link
) == REG_INC
)
2254 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2255 (GET_CODE (x
) == COND_EXEC
2256 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2260 switch (code
= GET_CODE (x
))
2264 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2268 cond
= COND_EXEC_TEST (x
);
2269 x
= COND_EXEC_CODE (x
);
2275 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2277 rtx sub
= XVECEXP (x
, 0, i
);
2278 switch (code
= GET_CODE (sub
))
2281 if (cond
!= NULL_RTX
)
2284 cond
= COND_EXEC_TEST (sub
);
2285 sub
= COND_EXEC_CODE (sub
);
2286 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2292 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2307 /* Process a single set, which appears in INSN. REG (which may not
2308 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2309 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2310 If the set is conditional (because it appear in a COND_EXEC), COND
2311 will be the condition. */
2314 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2315 struct propagate_block_info
*pbi
;
2317 rtx reg
, cond
, insn
;
2320 int regno_first
= -1, regno_last
= -1;
2321 unsigned long not_dead
= 0;
2324 /* Modifying just one hardware register of a multi-reg value or just a
2325 byte field of a register does not mean the value from before this insn
2326 is now dead. Of course, if it was dead after it's unused now. */
2328 switch (GET_CODE (reg
))
2331 /* Some targets place small structures in registers for return values of
2332 functions. We have to detect this case specially here to get correct
2333 flow information. */
2334 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2335 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2336 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2342 case STRICT_LOW_PART
:
2343 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2345 reg
= XEXP (reg
, 0);
2346 while (GET_CODE (reg
) == SUBREG
2347 || GET_CODE (reg
) == ZERO_EXTRACT
2348 || GET_CODE (reg
) == SIGN_EXTRACT
2349 || GET_CODE (reg
) == STRICT_LOW_PART
);
2350 if (GET_CODE (reg
) == MEM
)
2352 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2356 regno_last
= regno_first
= REGNO (reg
);
2357 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2358 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2362 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2364 enum machine_mode outer_mode
= GET_MODE (reg
);
2365 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2367 /* Identify the range of registers affected. This is moderately
2368 tricky for hard registers. See alter_subreg. */
2370 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2371 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2373 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2376 regno_last
= (regno_first
2377 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2379 /* Since we've just adjusted the register number ranges, make
2380 sure REG matches. Otherwise some_was_live will be clear
2381 when it shouldn't have been, and we'll create incorrect
2382 REG_UNUSED notes. */
2383 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2387 /* If the number of words in the subreg is less than the number
2388 of words in the full register, we have a well-defined partial
2389 set. Otherwise the high bits are undefined.
2391 This is only really applicable to pseudos, since we just took
2392 care of multi-word hard registers. */
2393 if (((GET_MODE_SIZE (outer_mode
)
2394 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2395 < ((GET_MODE_SIZE (inner_mode
)
2396 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2397 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2400 reg
= SUBREG_REG (reg
);
2404 reg
= SUBREG_REG (reg
);
2411 /* If this set is a MEM, then it kills any aliased writes.
2412 If this set is a REG, then it kills any MEMs which use the reg. */
2413 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
2415 if (GET_CODE (reg
) == REG
)
2416 invalidate_mems_from_set (pbi
, reg
);
2418 /* If the memory reference had embedded side effects (autoincrement
2419 address modes. Then we may need to kill some entries on the
2421 if (insn
&& GET_CODE (reg
) == MEM
)
2422 invalidate_mems_from_autoinc (pbi
, insn
);
2424 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2425 /* ??? With more effort we could track conditional memory life. */
2427 /* There are no REG_INC notes for SP, so we can't assume we'll see
2428 everything that invalidates it. To be safe, don't eliminate any
2429 stores though SP; none of them should be redundant anyway. */
2430 && ! reg_mentioned_p (stack_pointer_rtx
, reg
))
2431 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2434 if (GET_CODE (reg
) == REG
2435 && ! (regno_first
== FRAME_POINTER_REGNUM
2436 && (! reload_completed
|| frame_pointer_needed
))
2437 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2438 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2439 && (! reload_completed
|| frame_pointer_needed
))
2441 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2442 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2446 int some_was_live
= 0, some_was_dead
= 0;
2448 for (i
= regno_first
; i
<= regno_last
; ++i
)
2450 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2453 /* Order of the set operation matters here since both
2454 sets may be the same. */
2455 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2456 if (cond
!= NULL_RTX
2457 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2458 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2460 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2462 if (code
!= CLOBBER
)
2463 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2465 some_was_live
|= needed_regno
;
2466 some_was_dead
|= ! needed_regno
;
2469 #ifdef HAVE_conditional_execution
2470 /* Consider conditional death in deciding that the register needs
2472 if (some_was_live
&& ! not_dead
2473 /* The stack pointer is never dead. Well, not strictly true,
2474 but it's very difficult to tell from here. Hopefully
2475 combine_stack_adjustments will fix up the most egregious
2477 && regno_first
!= STACK_POINTER_REGNUM
)
2479 for (i
= regno_first
; i
<= regno_last
; ++i
)
2480 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2481 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2485 /* Additional data to record if this is the final pass. */
2486 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2487 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2490 register int blocknum
= pbi
->bb
->index
;
2493 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2495 y
= pbi
->reg_next_use
[regno_first
];
2497 /* The next use is no longer next, since a store intervenes. */
2498 for (i
= regno_first
; i
<= regno_last
; ++i
)
2499 pbi
->reg_next_use
[i
] = 0;
2502 if (flags
& PROP_REG_INFO
)
2504 for (i
= regno_first
; i
<= regno_last
; ++i
)
2506 /* Count (weighted) references, stores, etc. This counts a
2507 register twice if it is modified, but that is correct. */
2508 REG_N_SETS (i
) += 1;
2509 REG_N_REFS (i
) += 1;
2510 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2512 /* The insns where a reg is live are normally counted
2513 elsewhere, but we want the count to include the insn
2514 where the reg is set, and the normal counting mechanism
2515 would not count it. */
2516 REG_LIVE_LENGTH (i
) += 1;
2519 /* If this is a hard reg, record this function uses the reg. */
2520 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2522 for (i
= regno_first
; i
<= regno_last
; i
++)
2523 regs_ever_live
[i
] = 1;
2527 /* Keep track of which basic blocks each reg appears in. */
2528 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2529 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2530 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2531 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2535 if (! some_was_dead
)
2537 if (flags
& PROP_LOG_LINKS
)
2539 /* Make a logical link from the next following insn
2540 that uses this register, back to this insn.
2541 The following insns have already been processed.
2543 We don't build a LOG_LINK for hard registers containing
2544 in ASM_OPERANDs. If these registers get replaced,
2545 we might wind up changing the semantics of the insn,
2546 even if reload can make what appear to be valid
2547 assignments later. */
2548 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2549 && (regno_first
>= FIRST_PSEUDO_REGISTER
2550 || asm_noperands (PATTERN (y
)) < 0))
2551 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2556 else if (! some_was_live
)
2558 if (flags
& PROP_REG_INFO
)
2559 REG_N_DEATHS (regno_first
) += 1;
2561 if (flags
& PROP_DEATH_NOTES
)
2563 /* Note that dead stores have already been deleted
2564 when possible. If we get here, we have found a
2565 dead store that cannot be eliminated (because the
2566 same insn does something useful). Indicate this
2567 by marking the reg being set as dying here. */
2569 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2574 if (flags
& PROP_DEATH_NOTES
)
2576 /* This is a case where we have a multi-word hard register
2577 and some, but not all, of the words of the register are
2578 needed in subsequent insns. Write REG_UNUSED notes
2579 for those parts that were not needed. This case should
2582 for (i
= regno_first
; i
<= regno_last
; ++i
)
2583 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2585 = alloc_EXPR_LIST (REG_UNUSED
,
2586 gen_rtx_REG (reg_raw_mode
[i
], i
),
2592 /* Mark the register as being dead. */
2594 /* The stack pointer is never dead. Well, not strictly true,
2595 but it's very difficult to tell from here. Hopefully
2596 combine_stack_adjustments will fix up the most egregious
2598 && regno_first
!= STACK_POINTER_REGNUM
)
2600 for (i
= regno_first
; i
<= regno_last
; ++i
)
2601 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2602 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2605 else if (GET_CODE (reg
) == REG
)
2607 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2608 pbi
->reg_next_use
[regno_first
] = 0;
2611 /* If this is the last pass and this is a SCRATCH, show it will be dying
2612 here and count it. */
2613 else if (GET_CODE (reg
) == SCRATCH
)
2615 if (flags
& PROP_DEATH_NOTES
)
2617 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2621 #ifdef HAVE_conditional_execution
2622 /* Mark REGNO conditionally dead.
2623 Return true if the register is now unconditionally dead. */
2626 mark_regno_cond_dead (pbi
, regno
, cond
)
2627 struct propagate_block_info
*pbi
;
2631 /* If this is a store to a predicate register, the value of the
2632 predicate is changing, we don't know that the predicate as seen
2633 before is the same as that seen after. Flush all dependent
2634 conditions from reg_cond_dead. This will make all such
2635 conditionally live registers unconditionally live. */
2636 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2637 flush_reg_cond_reg (pbi
, regno
);
2639 /* If this is an unconditional store, remove any conditional
2640 life that may have existed. */
2641 if (cond
== NULL_RTX
)
2642 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2645 splay_tree_node node
;
2646 struct reg_cond_life_info
*rcli
;
2649 /* Otherwise this is a conditional set. Record that fact.
2650 It may have been conditionally used, or there may be a
2651 subsequent set with a complimentary condition. */
2653 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2656 /* The register was unconditionally live previously.
2657 Record the current condition as the condition under
2658 which it is dead. */
2659 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2660 rcli
->condition
= cond
;
2661 rcli
->stores
= cond
;
2662 rcli
->orig_condition
= const0_rtx
;
2663 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2664 (splay_tree_value
) rcli
);
2666 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2668 /* Not unconditionaly dead. */
2673 /* The register was conditionally live previously.
2674 Add the new condition to the old. */
2675 rcli
= (struct reg_cond_life_info
*) node
->value
;
2676 ncond
= rcli
->condition
;
2677 ncond
= ior_reg_cond (ncond
, cond
, 1);
2678 if (rcli
->stores
== const0_rtx
)
2679 rcli
->stores
= cond
;
2680 else if (rcli
->stores
!= const1_rtx
)
2681 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2683 /* If the register is now unconditionally dead, remove the entry
2684 in the splay_tree. A register is unconditionally dead if the
2685 dead condition ncond is true. A register is also unconditionally
2686 dead if the sum of all conditional stores is an unconditional
2687 store (stores is true), and the dead condition is identically the
2688 same as the original dead condition initialized at the end of
2689 the block. This is a pointer compare, not an rtx_equal_p
2691 if (ncond
== const1_rtx
2692 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2693 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2696 rcli
->condition
= ncond
;
2698 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2700 /* Not unconditionaly dead. */
2709 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2712 free_reg_cond_life_info (value
)
2713 splay_tree_value value
;
2715 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2719 /* Helper function for flush_reg_cond_reg. */
2722 flush_reg_cond_reg_1 (node
, data
)
2723 splay_tree_node node
;
2726 struct reg_cond_life_info
*rcli
;
2727 int *xdata
= (int *) data
;
2728 unsigned int regno
= xdata
[0];
2730 /* Don't need to search if last flushed value was farther on in
2731 the in-order traversal. */
2732 if (xdata
[1] >= (int) node
->key
)
2735 /* Splice out portions of the expression that refer to regno. */
2736 rcli
= (struct reg_cond_life_info
*) node
->value
;
2737 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2738 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2739 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2741 /* If the entire condition is now false, signal the node to be removed. */
2742 if (rcli
->condition
== const0_rtx
)
2744 xdata
[1] = node
->key
;
2747 else if (rcli
->condition
== const1_rtx
)
2753 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2756 flush_reg_cond_reg (pbi
, regno
)
2757 struct propagate_block_info
*pbi
;
2764 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2765 flush_reg_cond_reg_1
, pair
) == -1)
2766 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
2768 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
2771 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2772 For ior/and, the ADD flag determines whether we want to add the new
2773 condition X to the old one unconditionally. If it is zero, we will
2774 only return a new expression if X allows us to simplify part of
2775 OLD, otherwise we return OLD unchanged to the caller.
2776 If ADD is nonzero, we will return a new condition in all cases. The
2777 toplevel caller of one of these functions should always pass 1 for
2781 ior_reg_cond (old
, x
, add
)
2787 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
2789 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
2790 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
2791 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2793 if (GET_CODE (x
) == GET_CODE (old
)
2794 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2798 return gen_rtx_IOR (0, old
, x
);
2801 switch (GET_CODE (old
))
2804 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
2805 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
2806 if (op0
!= XEXP (old
, 0) || op1
!= XEXP (old
, 1))
2808 if (op0
== const0_rtx
)
2810 if (op1
== const0_rtx
)
2812 if (op0
== const1_rtx
|| op1
== const1_rtx
)
2814 if (op0
== XEXP (old
, 0))
2815 op0
= gen_rtx_IOR (0, op0
, x
);
2817 op1
= gen_rtx_IOR (0, op1
, x
);
2818 return gen_rtx_IOR (0, op0
, op1
);
2822 return gen_rtx_IOR (0, old
, x
);
2825 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
2826 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
2827 if (op0
!= XEXP (old
, 0) || op1
!= XEXP (old
, 1))
2829 if (op0
== const1_rtx
)
2831 if (op1
== const1_rtx
)
2833 if (op0
== const0_rtx
|| op1
== const0_rtx
)
2835 if (op0
== XEXP (old
, 0))
2836 op0
= gen_rtx_IOR (0, op0
, x
);
2838 op1
= gen_rtx_IOR (0, op1
, x
);
2839 return gen_rtx_AND (0, op0
, op1
);
2843 return gen_rtx_IOR (0, old
, x
);
2846 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
2847 if (op0
!= XEXP (old
, 0))
2848 return not_reg_cond (op0
);
2851 return gen_rtx_IOR (0, old
, x
);
2862 enum rtx_code x_code
;
2864 if (x
== const0_rtx
)
2866 else if (x
== const1_rtx
)
2868 x_code
= GET_CODE (x
);
2871 if (GET_RTX_CLASS (x_code
) == '<'
2872 && GET_CODE (XEXP (x
, 0)) == REG
)
2874 if (XEXP (x
, 1) != const0_rtx
)
2877 return gen_rtx_fmt_ee (reverse_condition (x_code
),
2878 VOIDmode
, XEXP (x
, 0), const0_rtx
);
2880 return gen_rtx_NOT (0, x
);
2884 and_reg_cond (old
, x
, add
)
2890 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
2892 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
2893 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
2894 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2896 if (GET_CODE (x
) == GET_CODE (old
)
2897 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2901 return gen_rtx_AND (0, old
, x
);
2904 switch (GET_CODE (old
))
2907 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
2908 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
2909 if (op0
!= XEXP (old
, 0) || op1
!= XEXP (old
, 1))
2911 if (op0
== const0_rtx
)
2913 if (op1
== const0_rtx
)
2915 if (op0
== const1_rtx
|| op1
== const1_rtx
)
2917 if (op0
== XEXP (old
, 0))
2918 op0
= gen_rtx_AND (0, op0
, x
);
2920 op1
= gen_rtx_AND (0, op1
, x
);
2921 return gen_rtx_IOR (0, op0
, op1
);
2925 return gen_rtx_AND (0, old
, x
);
2928 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
2929 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
2930 if (op0
!= XEXP (old
, 0) || op1
!= XEXP (old
, 1))
2932 if (op0
== const1_rtx
)
2934 if (op1
== const1_rtx
)
2936 if (op0
== const0_rtx
|| op1
== const0_rtx
)
2938 if (op0
== XEXP (old
, 0))
2939 op0
= gen_rtx_AND (0, op0
, x
);
2941 op1
= gen_rtx_AND (0, op1
, x
);
2942 return gen_rtx_AND (0, op0
, op1
);
2947 /* If X is identical to one of the existing terms of the AND,
2948 then just return what we already have. */
2949 /* ??? There really should be some sort of recursive check here in
2950 case there are nested ANDs. */
2951 if ((GET_CODE (XEXP (old
, 0)) == GET_CODE (x
)
2952 && REGNO (XEXP (XEXP (old
, 0), 0)) == REGNO (XEXP (x
, 0)))
2953 || (GET_CODE (XEXP (old
, 1)) == GET_CODE (x
)
2954 && REGNO (XEXP (XEXP (old
, 1), 0)) == REGNO (XEXP (x
, 0))))
2957 return gen_rtx_AND (0, old
, x
);
2960 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
2961 if (op0
!= XEXP (old
, 0))
2962 return not_reg_cond (op0
);
2965 return gen_rtx_AND (0, old
, x
);
2972 /* Given a condition X, remove references to reg REGNO and return the
2973 new condition. The removal will be done so that all conditions
2974 involving REGNO are considered to evaluate to false. This function
2975 is used when the value of REGNO changes. */
2978 elim_reg_cond (x
, regno
)
2984 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
2986 if (REGNO (XEXP (x
, 0)) == regno
)
2991 switch (GET_CODE (x
))
2994 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
2995 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
2996 if (op0
== const0_rtx
|| op1
== const0_rtx
)
2998 if (op0
== const1_rtx
)
3000 if (op1
== const1_rtx
)
3002 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3004 return gen_rtx_AND (0, op0
, op1
);
3007 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3008 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3009 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3011 if (op0
== const0_rtx
)
3013 if (op1
== const0_rtx
)
3015 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3017 return gen_rtx_IOR (0, op0
, op1
);
3020 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3021 if (op0
== const0_rtx
)
3023 if (op0
== const1_rtx
)
3025 if (op0
!= XEXP (x
, 0))
3026 return not_reg_cond (op0
);
3033 #endif /* HAVE_conditional_execution */
3037 /* Try to substitute the auto-inc expression INC as the address inside
3038 MEM which occurs in INSN. Currently, the address of MEM is an expression
3039 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3040 that has a single set whose source is a PLUS of INCR_REG and something
3044 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3045 struct propagate_block_info
*pbi
;
3046 rtx inc
, insn
, mem
, incr
, incr_reg
;
3048 int regno
= REGNO (incr_reg
);
3049 rtx set
= single_set (incr
);
3050 rtx q
= SET_DEST (set
);
3051 rtx y
= SET_SRC (set
);
3052 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3054 /* Make sure this reg appears only once in this insn. */
3055 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3058 if (dead_or_set_p (incr
, incr_reg
)
3059 /* Mustn't autoinc an eliminable register. */
3060 && (regno
>= FIRST_PSEUDO_REGISTER
3061 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3063 /* This is the simple case. Try to make the auto-inc. If
3064 we can't, we are done. Otherwise, we will do any
3065 needed updates below. */
3066 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3069 else if (GET_CODE (q
) == REG
3070 /* PREV_INSN used here to check the semi-open interval
3072 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3073 /* We must also check for sets of q as q may be
3074 a call clobbered hard register and there may
3075 be a call between PREV_INSN (insn) and incr. */
3076 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3078 /* We have *p followed sometime later by q = p+size.
3079 Both p and q must be live afterward,
3080 and q is not used between INSN and its assignment.
3081 Change it to q = p, ...*q..., q = q+size.
3082 Then fall into the usual case. */
3086 emit_move_insn (q
, incr_reg
);
3087 insns
= get_insns ();
3090 /* If we can't make the auto-inc, or can't make the
3091 replacement into Y, exit. There's no point in making
3092 the change below if we can't do the auto-inc and doing
3093 so is not correct in the pre-inc case. */
3096 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3097 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3098 if (! apply_change_group ())
3101 /* We now know we'll be doing this change, so emit the
3102 new insn(s) and do the updates. */
3103 emit_insns_before (insns
, insn
);
3105 if (pbi
->bb
->head
== insn
)
3106 pbi
->bb
->head
= insns
;
3108 /* INCR will become a NOTE and INSN won't contain a
3109 use of INCR_REG. If a use of INCR_REG was just placed in
3110 the insn before INSN, make that the next use.
3111 Otherwise, invalidate it. */
3112 if (GET_CODE (PREV_INSN (insn
)) == INSN
3113 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3114 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3115 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3117 pbi
->reg_next_use
[regno
] = 0;
3122 /* REGNO is now used in INCR which is below INSN, but
3123 it previously wasn't live here. If we don't mark
3124 it as live, we'll put a REG_DEAD note for it
3125 on this insn, which is incorrect. */
3126 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3128 /* If there are any calls between INSN and INCR, show
3129 that REGNO now crosses them. */
3130 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3131 if (GET_CODE (temp
) == CALL_INSN
)
3132 REG_N_CALLS_CROSSED (regno
)++;
3134 /* Invalidate alias info for Q since we just changed its value. */
3135 clear_reg_alias_info (q
);
3140 /* If we haven't returned, it means we were able to make the
3141 auto-inc, so update the status. First, record that this insn
3142 has an implicit side effect. */
3144 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3146 /* Modify the old increment-insn to simply copy
3147 the already-incremented value of our register. */
3148 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3151 /* If that makes it a no-op (copying the register into itself) delete
3152 it so it won't appear to be a "use" and a "set" of this
3154 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3156 /* If the original source was dead, it's dead now. */
3159 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3161 remove_note (incr
, note
);
3162 if (XEXP (note
, 0) != incr_reg
)
3163 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3166 PUT_CODE (incr
, NOTE
);
3167 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3168 NOTE_SOURCE_FILE (incr
) = 0;
3171 if (regno
>= FIRST_PSEUDO_REGISTER
)
3173 /* Count an extra reference to the reg. When a reg is
3174 incremented, spilling it is worse, so we want to make
3175 that less likely. */
3176 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3178 /* Count the increment as a setting of the register,
3179 even though it isn't a SET in rtl. */
3180 REG_N_SETS (regno
)++;
3184 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3188 find_auto_inc (pbi
, x
, insn
)
3189 struct propagate_block_info
*pbi
;
3193 rtx addr
= XEXP (x
, 0);
3194 HOST_WIDE_INT offset
= 0;
3195 rtx set
, y
, incr
, inc_val
;
3197 int size
= GET_MODE_SIZE (GET_MODE (x
));
3199 if (GET_CODE (insn
) == JUMP_INSN
)
3202 /* Here we detect use of an index register which might be good for
3203 postincrement, postdecrement, preincrement, or predecrement. */
3205 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3206 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3208 if (GET_CODE (addr
) != REG
)
3211 regno
= REGNO (addr
);
3213 /* Is the next use an increment that might make auto-increment? */
3214 incr
= pbi
->reg_next_use
[regno
];
3215 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3217 set
= single_set (incr
);
3218 if (set
== 0 || GET_CODE (set
) != SET
)
3222 if (GET_CODE (y
) != PLUS
)
3225 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3226 inc_val
= XEXP (y
, 1);
3227 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3228 inc_val
= XEXP (y
, 0);
3232 if (GET_CODE (inc_val
) == CONST_INT
)
3234 if (HAVE_POST_INCREMENT
3235 && (INTVAL (inc_val
) == size
&& offset
== 0))
3236 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3238 else if (HAVE_POST_DECREMENT
3239 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3240 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3242 else if (HAVE_PRE_INCREMENT
3243 && (INTVAL (inc_val
) == size
&& offset
== size
))
3244 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3246 else if (HAVE_PRE_DECREMENT
3247 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3248 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3250 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3251 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3252 gen_rtx_PLUS (Pmode
,
3255 insn
, x
, incr
, addr
);
3257 else if (GET_CODE (inc_val
) == REG
3258 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3262 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3263 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3264 gen_rtx_PLUS (Pmode
,
3267 insn
, x
, incr
, addr
);
3271 #endif /* AUTO_INC_DEC */
3274 mark_used_reg (pbi
, reg
, cond
, insn
)
3275 struct propagate_block_info
*pbi
;
3277 rtx cond ATTRIBUTE_UNUSED
;
3280 unsigned int regno_first
, regno_last
, i
;
3281 int some_was_live
, some_was_dead
, some_not_set
;
3283 regno_last
= regno_first
= REGNO (reg
);
3284 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3285 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3287 /* Find out if any of this register is live after this instruction. */
3288 some_was_live
= some_was_dead
= 0;
3289 for (i
= regno_first
; i
<= regno_last
; ++i
)
3291 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3292 some_was_live
|= needed_regno
;
3293 some_was_dead
|= ! needed_regno
;
3296 /* Find out if any of the register was set this insn. */
3298 for (i
= regno_first
; i
<= regno_last
; ++i
)
3299 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3301 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3303 /* Record where each reg is used, so when the reg is set we know
3304 the next insn that uses it. */
3305 pbi
->reg_next_use
[regno_first
] = insn
;
3308 if (pbi
->flags
& PROP_REG_INFO
)
3310 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3312 /* If this is a register we are going to try to eliminate,
3313 don't mark it live here. If we are successful in
3314 eliminating it, it need not be live unless it is used for
3315 pseudos, in which case it will have been set live when it
3316 was allocated to the pseudos. If the register will not
3317 be eliminated, reload will set it live at that point.
3319 Otherwise, record that this function uses this register. */
3320 /* ??? The PPC backend tries to "eliminate" on the pic
3321 register to itself. This should be fixed. In the mean
3322 time, hack around it. */
3324 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3325 && (regno_first
== FRAME_POINTER_REGNUM
3326 || regno_first
== ARG_POINTER_REGNUM
)))
3327 for (i
= regno_first
; i
<= regno_last
; ++i
)
3328 regs_ever_live
[i
] = 1;
3332 /* Keep track of which basic block each reg appears in. */
3334 register int blocknum
= pbi
->bb
->index
;
3335 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3336 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3337 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3338 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3340 /* Count (weighted) number of uses of each reg. */
3341 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3342 REG_N_REFS (regno_first
)++;
3346 /* Record and count the insns in which a reg dies. If it is used in
3347 this insn and was dead below the insn then it dies in this insn.
3348 If it was set in this insn, we do not make a REG_DEAD note;
3349 likewise if we already made such a note. */
3350 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3354 /* Check for the case where the register dying partially
3355 overlaps the register set by this insn. */
3356 if (regno_first
!= regno_last
)
3357 for (i
= regno_first
; i
<= regno_last
; ++i
)
3358 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3360 /* If none of the words in X is needed, make a REG_DEAD note.
3361 Otherwise, we must make partial REG_DEAD notes. */
3362 if (! some_was_live
)
3364 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3365 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3367 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3369 if (pbi
->flags
& PROP_REG_INFO
)
3370 REG_N_DEATHS (regno_first
)++;
3374 /* Don't make a REG_DEAD note for a part of a register
3375 that is set in the insn. */
3376 for (i
= regno_first
; i
<= regno_last
; ++i
)
3377 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3378 && ! dead_or_set_regno_p (insn
, i
))
3380 = alloc_EXPR_LIST (REG_DEAD
,
3381 gen_rtx_REG (reg_raw_mode
[i
], i
),
3386 /* Mark the register as being live. */
3387 for (i
= regno_first
; i
<= regno_last
; ++i
)
3389 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3391 #ifdef HAVE_conditional_execution
3392 /* If this is a conditional use, record that fact. If it is later
3393 conditionally set, we'll know to kill the register. */
3394 if (cond
!= NULL_RTX
)
3396 splay_tree_node node
;
3397 struct reg_cond_life_info
*rcli
;
3402 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3405 /* The register was unconditionally live previously.
3406 No need to do anything. */
3410 /* The register was conditionally live previously.
3411 Subtract the new life cond from the old death cond. */
3412 rcli
= (struct reg_cond_life_info
*) node
->value
;
3413 ncond
= rcli
->condition
;
3414 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3416 /* If the register is now unconditionally live,
3417 remove the entry in the splay_tree. */
3418 if (ncond
== const0_rtx
)
3419 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3422 rcli
->condition
= ncond
;
3423 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3424 REGNO (XEXP (cond
, 0)));
3430 /* The register was not previously live at all. Record
3431 the condition under which it is still dead. */
3432 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3433 rcli
->condition
= not_reg_cond (cond
);
3434 rcli
->stores
= const0_rtx
;
3435 rcli
->orig_condition
= const0_rtx
;
3436 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3437 (splay_tree_value
) rcli
);
3439 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3442 else if (some_was_live
)
3444 /* The register may have been conditionally live previously, but
3445 is now unconditionally live. Remove it from the conditionally
3446 dead list, so that a conditional set won't cause us to think
3448 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3454 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3455 This is done assuming the registers needed from X are those that
3456 have 1-bits in PBI->REG_LIVE.
3458 INSN is the containing instruction. If INSN is dead, this function
3462 mark_used_regs (pbi
, x
, cond
, insn
)
3463 struct propagate_block_info
*pbi
;
3466 register RTX_CODE code
;
3468 int flags
= pbi
->flags
;
3471 code
= GET_CODE (x
);
3491 /* If we are clobbering a MEM, mark any registers inside the address
3493 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3494 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3498 /* Don't bother watching stores to mems if this is not the
3499 final pass. We'll not be deleting dead stores this round. */
3500 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
3502 /* Invalidate the data for the last MEM stored, but only if MEM is
3503 something that can be stored into. */
3504 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3505 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3506 /* Needn't clear the memory set list. */
3510 rtx temp
= pbi
->mem_set_list
;
3511 rtx prev
= NULL_RTX
;
3516 next
= XEXP (temp
, 1);
3517 if (anti_dependence (XEXP (temp
, 0), x
))
3519 /* Splice temp out of the list. */
3521 XEXP (prev
, 1) = next
;
3523 pbi
->mem_set_list
= next
;
3524 free_EXPR_LIST_node (temp
);
3525 pbi
->mem_set_list_len
--;
3533 /* If the memory reference had embedded side effects (autoincrement
3534 address modes. Then we may need to kill some entries on the
3537 invalidate_mems_from_autoinc (pbi
, insn
);
3541 if (flags
& PROP_AUTOINC
)
3542 find_auto_inc (pbi
, x
, insn
);
3547 #ifdef CLASS_CANNOT_CHANGE_MODE
3548 if (GET_CODE (SUBREG_REG (x
)) == REG
3549 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3550 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3551 GET_MODE (SUBREG_REG (x
))))
3552 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3555 /* While we're here, optimize this case. */
3557 if (GET_CODE (x
) != REG
)
3562 /* See a register other than being set => mark it as needed. */
3563 mark_used_reg (pbi
, x
, cond
, insn
);
3568 register rtx testreg
= SET_DEST (x
);
3571 /* If storing into MEM, don't show it as being used. But do
3572 show the address as being used. */
3573 if (GET_CODE (testreg
) == MEM
)
3576 if (flags
& PROP_AUTOINC
)
3577 find_auto_inc (pbi
, testreg
, insn
);
3579 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3580 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3584 /* Storing in STRICT_LOW_PART is like storing in a reg
3585 in that this SET might be dead, so ignore it in TESTREG.
3586 but in some other ways it is like using the reg.
3588 Storing in a SUBREG or a bit field is like storing the entire
3589 register in that if the register's value is not used
3590 then this SET is not needed. */
3591 while (GET_CODE (testreg
) == STRICT_LOW_PART
3592 || GET_CODE (testreg
) == ZERO_EXTRACT
3593 || GET_CODE (testreg
) == SIGN_EXTRACT
3594 || GET_CODE (testreg
) == SUBREG
)
3596 #ifdef CLASS_CANNOT_CHANGE_MODE
3597 if (GET_CODE (testreg
) == SUBREG
3598 && GET_CODE (SUBREG_REG (testreg
)) == REG
3599 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3600 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3601 GET_MODE (testreg
)))
3602 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3605 /* Modifying a single register in an alternate mode
3606 does not use any of the old value. But these other
3607 ways of storing in a register do use the old value. */
3608 if (GET_CODE (testreg
) == SUBREG
3609 && !(REG_SIZE (SUBREG_REG (testreg
)) > REG_SIZE (testreg
)))
3614 testreg
= XEXP (testreg
, 0);
3617 /* If this is a store into a register or group of registers,
3618 recursively scan the value being stored. */
3620 if ((GET_CODE (testreg
) == PARALLEL
3621 && GET_MODE (testreg
) == BLKmode
)
3622 || (GET_CODE (testreg
) == REG
3623 && (regno
= REGNO (testreg
),
3624 ! (regno
== FRAME_POINTER_REGNUM
3625 && (! reload_completed
|| frame_pointer_needed
)))
3626 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3627 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3628 && (! reload_completed
|| frame_pointer_needed
))
3630 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3631 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3636 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3637 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3644 case UNSPEC_VOLATILE
:
3648 /* Traditional and volatile asm instructions must be considered to use
3649 and clobber all hard registers, all pseudo-registers and all of
3650 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3652 Consider for instance a volatile asm that changes the fpu rounding
3653 mode. An insn should not be moved across this even if it only uses
3654 pseudo-regs because it might give an incorrectly rounded result.
3656 ?!? Unfortunately, marking all hard registers as live causes massive
3657 problems for the register allocator and marking all pseudos as live
3658 creates mountains of uninitialized variable warnings.
3660 So for now, just clear the memory set list and mark any regs
3661 we can find in ASM_OPERANDS as used. */
3662 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3664 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3665 pbi
->mem_set_list_len
= 0;
3668 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3669 We can not just fall through here since then we would be confused
3670 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3671 traditional asms unlike their normal usage. */
3672 if (code
== ASM_OPERANDS
)
3676 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3677 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3683 if (cond
!= NULL_RTX
)
3686 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3688 cond
= COND_EXEC_TEST (x
);
3689 x
= COND_EXEC_CODE (x
);
3693 /* We _do_not_ want to scan operands of phi nodes. Operands of
3694 a phi function are evaluated only when control reaches this
3695 block along a particular edge. Therefore, regs that appear
3696 as arguments to phi should not be added to the global live at
3704 /* Recursively scan the operands of this expression. */
3707 register const char * const fmt
= GET_RTX_FORMAT (code
);
3710 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3714 /* Tail recursive case: save a function call level. */
3720 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3722 else if (fmt
[i
] == 'E')
3725 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3726 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3735 try_pre_increment_1 (pbi
, insn
)
3736 struct propagate_block_info
*pbi
;
3739 /* Find the next use of this reg. If in same basic block,
3740 make it do pre-increment or pre-decrement if appropriate. */
3741 rtx x
= single_set (insn
);
3742 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3743 * INTVAL (XEXP (SET_SRC (x
), 1)));
3744 int regno
= REGNO (SET_DEST (x
));
3745 rtx y
= pbi
->reg_next_use
[regno
];
3747 && SET_DEST (x
) != stack_pointer_rtx
3748 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
3749 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3750 mode would be better. */
3751 && ! dead_or_set_p (y
, SET_DEST (x
))
3752 && try_pre_increment (y
, SET_DEST (x
), amount
))
3754 /* We have found a suitable auto-increment and already changed
3755 insn Y to do it. So flush this increment instruction. */
3756 propagate_block_delete_insn (pbi
->bb
, insn
);
3758 /* Count a reference to this reg for the increment insn we are
3759 deleting. When a reg is incremented, spilling it is worse,
3760 so we want to make that less likely. */
3761 if (regno
>= FIRST_PSEUDO_REGISTER
)
3763 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3764 REG_N_SETS (regno
)++;
3767 /* Flush any remembered memories depending on the value of
3768 the incremented register. */
3769 invalidate_mems_from_set (pbi
, SET_DEST (x
));
3776 /* Try to change INSN so that it does pre-increment or pre-decrement
3777 addressing on register REG in order to add AMOUNT to REG.
3778 AMOUNT is negative for pre-decrement.
3779 Returns 1 if the change could be made.
3780 This checks all about the validity of the result of modifying INSN. */
3783 try_pre_increment (insn
, reg
, amount
)
3785 HOST_WIDE_INT amount
;
3789 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3790 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3792 /* Nonzero if we can try to make a post-increment or post-decrement.
3793 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3794 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3795 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3798 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3801 /* From the sign of increment, see which possibilities are conceivable
3802 on this target machine. */
3803 if (HAVE_PRE_INCREMENT
&& amount
> 0)
3805 if (HAVE_POST_INCREMENT
&& amount
> 0)
3808 if (HAVE_PRE_DECREMENT
&& amount
< 0)
3810 if (HAVE_POST_DECREMENT
&& amount
< 0)
3813 if (! (pre_ok
|| post_ok
))
3816 /* It is not safe to add a side effect to a jump insn
3817 because if the incremented register is spilled and must be reloaded
3818 there would be no way to store the incremented value back in memory. */
3820 if (GET_CODE (insn
) == JUMP_INSN
)
3825 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
3826 if (post_ok
&& (use
== 0 || use
== (rtx
) 1))
3828 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
3832 if (use
== 0 || use
== (rtx
) 1)
3835 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
3838 /* See if this combination of instruction and addressing mode exists. */
3839 if (! validate_change (insn
, &XEXP (use
, 0),
3840 gen_rtx_fmt_e (amount
> 0
3841 ? (do_post
? POST_INC
: PRE_INC
)
3842 : (do_post
? POST_DEC
: PRE_DEC
),
3846 /* Record that this insn now has an implicit side effect on X. */
3847 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
3851 #endif /* AUTO_INC_DEC */
3853 /* Find the place in the rtx X where REG is used as a memory address.
3854 Return the MEM rtx that so uses it.
3855 If PLUSCONST is nonzero, search instead for a memory address equivalent to
3856 (plus REG (const_int PLUSCONST)).
3858 If such an address does not appear, return 0.
3859 If REG appears more than once, or is used other than in such an address,
3863 find_use_as_address (x
, reg
, plusconst
)
3866 HOST_WIDE_INT plusconst
;
3868 enum rtx_code code
= GET_CODE (x
);
3869 const char * const fmt
= GET_RTX_FORMAT (code
);
3871 register rtx value
= 0;
3874 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
3877 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
3878 && XEXP (XEXP (x
, 0), 0) == reg
3879 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
3880 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
3883 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
3885 /* If REG occurs inside a MEM used in a bit-field reference,
3886 that is unacceptable. */
3887 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
3888 return (rtx
) (HOST_WIDE_INT
) 1;
3892 return (rtx
) (HOST_WIDE_INT
) 1;
3894 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3898 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
3902 return (rtx
) (HOST_WIDE_INT
) 1;
3904 else if (fmt
[i
] == 'E')
3907 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3909 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
3913 return (rtx
) (HOST_WIDE_INT
) 1;
3921 /* Write information about registers and basic blocks into FILE.
3922 This is part of making a debugging dump. */
3925 dump_regset (r
, outf
)
3932 fputs (" (nil)", outf
);
3936 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
3938 fprintf (outf
, " %d", i
);
3939 if (i
< FIRST_PSEUDO_REGISTER
)
3940 fprintf (outf
, " [%s]",
3945 /* Print a human-reaable representation of R on the standard error
3946 stream. This function is designed to be used from within the
3953 dump_regset (r
, stderr
);
3954 putc ('\n', stderr
);
3957 /* Dump the rtl into the current debugging dump file, then abort. */
3960 print_rtl_and_abort_fcn (file
, line
, function
)
3963 const char *function
;
3967 print_rtl_with_bb (rtl_dump_file
, get_insns ());
3968 fclose (rtl_dump_file
);
3971 fancy_abort (file
, line
, function
);
3974 /* Recompute register set/reference counts immediately prior to register
3977 This avoids problems with set/reference counts changing to/from values
3978 which have special meanings to the register allocators.
3980 Additionally, the reference counts are the primary component used by the
3981 register allocators to prioritize pseudos for allocation to hard regs.
3982 More accurate reference counts generally lead to better register allocation.
3984 F is the first insn to be scanned.
3986 LOOP_STEP denotes how much loop_depth should be incremented per
3987 loop nesting level in order to increase the ref count more for
3988 references in a loop.
3990 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
3991 possibly other information which is used by the register allocators. */
3994 recompute_reg_usage (f
, loop_step
)
3995 rtx f ATTRIBUTE_UNUSED
;
3996 int loop_step ATTRIBUTE_UNUSED
;
3998 allocate_reg_life_data ();
3999 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4002 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4003 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4004 of the number of registers that died. */
4007 count_or_remove_death_notes (blocks
, kill
)
4013 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
4018 if (blocks
&& ! TEST_BIT (blocks
, i
))
4021 bb
= BASIC_BLOCK (i
);
4023 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4027 rtx
*pprev
= ®_NOTES (insn
);
4032 switch (REG_NOTE_KIND (link
))
4035 if (GET_CODE (XEXP (link
, 0)) == REG
)
4037 rtx reg
= XEXP (link
, 0);
4040 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4043 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4051 rtx next
= XEXP (link
, 1);
4052 free_EXPR_LIST_node (link
);
4053 *pprev
= link
= next
;
4059 pprev
= &XEXP (link
, 1);
4066 if (insn
== bb
->end
)
4073 /* Clear LOG_LINKS fields of insns in a chain.
4074 Also clear the global_live_at_{start,end} fields of the basic block
4078 clear_log_links (insns
)
4084 for (i
= insns
; i
; i
= NEXT_INSN (i
))
4088 for (b
= 0; b
< n_basic_blocks
; b
++)
4090 basic_block bb
= BASIC_BLOCK (b
);
4092 bb
->global_live_at_start
= NULL
;
4093 bb
->global_live_at_end
= NULL
;
4096 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
4097 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
4100 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4101 correspond to the hard registers, if any, set in that map. This
4102 could be done far more efficiently by having all sorts of special-cases
4103 with moving single words, but probably isn't worth the trouble. */
4106 reg_set_to_hard_reg_set (to
, from
)
4112 EXECUTE_IF_SET_IN_BITMAP
4115 if (i
>= FIRST_PSEUDO_REGISTER
)
4117 SET_HARD_REG_BIT (*to
, i
);