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 static int find_regno_partial
PARAMS ((rtx
*, void *));
311 #ifdef HAVE_conditional_execution
312 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
314 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
315 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
316 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
318 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
319 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
320 static rtx not_reg_cond
PARAMS ((rtx
));
321 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
324 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
325 rtx
, rtx
, rtx
, rtx
, rtx
));
326 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
328 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
330 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
332 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
334 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
336 void dump_flow_info
PARAMS ((FILE *));
337 void debug_flow_info
PARAMS ((void));
338 static void print_rtl_and_abort_fcn
PARAMS ((const char *, int,
342 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
344 static void invalidate_mems_from_autoinc
PARAMS ((struct propagate_block_info
*,
346 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
348 static void delete_dead_jumptables
PARAMS ((void));
349 static void clear_log_links
PARAMS ((sbitmap
));
353 check_function_return_warnings ()
355 if (warn_missing_noreturn
356 && !TREE_THIS_VOLATILE (cfun
->decl
)
357 && EXIT_BLOCK_PTR
->pred
== NULL
358 && (lang_missing_noreturn_ok_p
359 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
360 warning ("function might be possible candidate for attribute `noreturn'");
362 /* If we have a path to EXIT, then we do return. */
363 if (TREE_THIS_VOLATILE (cfun
->decl
)
364 && EXIT_BLOCK_PTR
->pred
!= NULL
)
365 warning ("`noreturn' function does return");
367 /* If the clobber_return_insn appears in some basic block, then we
368 do reach the end without returning a value. */
369 else if (warn_return_type
370 && cfun
->x_clobber_return_insn
!= NULL
371 && EXIT_BLOCK_PTR
->pred
!= NULL
)
373 int max_uid
= get_max_uid ();
375 /* If clobber_return_insn was excised by jump1, then renumber_insns
376 can make max_uid smaller than the number still recorded in our rtx.
377 That's fine, since this is a quick way of verifying that the insn
378 is no longer in the chain. */
379 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
381 /* Recompute insn->block mapping, since the initial mapping is
382 set before we delete unreachable blocks. */
383 if (BLOCK_FOR_INSN (cfun
->x_clobber_return_insn
) != NULL
)
384 warning ("control reaches end of non-void function");
389 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
390 note associated with the BLOCK. */
393 first_insn_after_basic_block_note (block
)
398 /* Get the first instruction in the block. */
401 if (insn
== NULL_RTX
)
403 if (GET_CODE (insn
) == CODE_LABEL
)
404 insn
= NEXT_INSN (insn
);
405 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
408 return NEXT_INSN (insn
);
411 /* Perform data flow analysis.
412 F is the first insn of the function; FLAGS is a set of PROP_* flags
413 to be used in accumulating flow info. */
416 life_analysis (f
, file
, flags
)
421 #ifdef ELIMINABLE_REGS
423 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
426 /* Record which registers will be eliminated. We use this in
429 CLEAR_HARD_REG_SET (elim_reg_set
);
431 #ifdef ELIMINABLE_REGS
432 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
433 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
435 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
439 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
441 /* The post-reload life analysis have (on a global basis) the same
442 registers live as was computed by reload itself. elimination
443 Otherwise offsets and such may be incorrect.
445 Reload will make some registers as live even though they do not
448 We don't want to create new auto-incs after reload, since they
449 are unlikely to be useful and can cause problems with shared
451 if (reload_completed
)
452 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
454 /* We want alias analysis information for local dead store elimination. */
455 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
456 init_alias_analysis ();
458 /* Always remove no-op moves. Do this before other processing so
459 that we don't have to keep re-scanning them. */
460 delete_noop_moves (f
);
461 purge_all_dead_edges (false);
463 /* Some targets can emit simpler epilogues if they know that sp was
464 not ever modified during the function. After reload, of course,
465 we've already emitted the epilogue so there's no sense searching. */
466 if (! reload_completed
)
467 notice_stack_pointer_modification (f
);
469 /* Allocate and zero out data structures that will record the
470 data from lifetime analysis. */
471 allocate_reg_life_data ();
472 allocate_bb_life_data ();
474 /* Find the set of registers live on function exit. */
475 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
477 /* "Update" life info from zero. It'd be nice to begin the
478 relaxation with just the exit and noreturn blocks, but that set
479 is not immediately handy. */
481 if (flags
& PROP_REG_INFO
)
482 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
483 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
486 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
487 end_alias_analysis ();
490 dump_flow_info (file
);
492 free_basic_block_vars (1);
494 #ifdef ENABLE_CHECKING
498 /* Search for any REG_LABEL notes which reference deleted labels. */
499 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
501 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
503 if (inote
&& GET_CODE (inote
) == NOTE_INSN_DELETED_LABEL
)
508 /* Removing dead insns should've made jumptables really dead. */
509 delete_dead_jumptables ();
512 /* A subroutine of verify_wide_reg, called through for_each_rtx.
513 Search for REGNO. If found, abort if it is not wider than word_mode. */
516 verify_wide_reg_1 (px
, pregno
)
521 unsigned int regno
= *(int *) pregno
;
523 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
525 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
532 /* A subroutine of verify_local_live_at_start. Search through insns
533 between HEAD and END looking for register REGNO. */
536 verify_wide_reg (regno
, head
, end
)
543 && for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
))
547 head
= NEXT_INSN (head
);
550 /* We didn't find the register at all. Something's way screwy. */
552 fprintf (rtl_dump_file
, "Aborting in verify_wide_reg; reg %d\n", regno
);
553 print_rtl_and_abort ();
556 /* A subroutine of update_life_info. Verify that there are no untoward
557 changes in live_at_start during a local update. */
560 verify_local_live_at_start (new_live_at_start
, bb
)
561 regset new_live_at_start
;
564 if (reload_completed
)
566 /* After reload, there are no pseudos, nor subregs of multi-word
567 registers. The regsets should exactly match. */
568 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
572 fprintf (rtl_dump_file
,
573 "live_at_start mismatch in bb %d, aborting\n",
575 debug_bitmap_file (rtl_dump_file
, bb
->global_live_at_start
);
576 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
578 print_rtl_and_abort ();
585 /* Find the set of changed registers. */
586 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
588 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
590 /* No registers should die. */
591 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
594 fprintf (rtl_dump_file
,
595 "Register %d died unexpectedly in block %d\n", i
,
597 print_rtl_and_abort ();
600 /* Verify that the now-live register is wider than word_mode. */
601 verify_wide_reg (i
, bb
->head
, bb
->end
);
606 /* Updates life information starting with the basic blocks set in BLOCKS.
607 If BLOCKS is null, consider it to be the universal set.
609 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
610 we are only expecting local modifications to basic blocks. If we find
611 extra registers live at the beginning of a block, then we either killed
612 useful data, or we have a broken split that wants data not provided.
613 If we find registers removed from live_at_start, that means we have
614 a broken peephole that is killing a register it shouldn't.
616 ??? This is not true in one situation -- when a pre-reload splitter
617 generates subregs of a multi-word pseudo, current life analysis will
618 lose the kill. So we _can_ have a pseudo go live. How irritating.
620 Including PROP_REG_INFO does not properly refresh regs_ever_live
621 unless the caller resets it to zero. */
624 update_life_info (blocks
, extent
, prop_flags
)
626 enum update_life_extent extent
;
630 regset_head tmp_head
;
633 tmp
= INITIALIZE_REG_SET (tmp_head
);
635 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
636 ? TV_LIFE_UPDATE
: TV_LIFE
);
638 /* Changes to the CFG are only allowed when
639 doing a global update for the entire CFG. */
640 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
641 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
644 /* Clear log links in case we are asked to (re)compute them. */
645 if (prop_flags
& PROP_LOG_LINKS
)
646 clear_log_links (blocks
);
648 /* For a global update, we go through the relaxation process again. */
649 if (extent
!= UPDATE_LIFE_LOCAL
)
655 calculate_global_regs_live (blocks
, blocks
,
656 prop_flags
& (PROP_SCAN_DEAD_CODE
657 | PROP_ALLOW_CFG_CHANGES
));
659 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
660 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
663 /* Removing dead code may allow the CFG to be simplified which
664 in turn may allow for further dead code detection / removal. */
665 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
667 basic_block bb
= BASIC_BLOCK (i
);
669 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
670 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
671 prop_flags
& (PROP_SCAN_DEAD_CODE
672 | PROP_KILL_DEAD_CODE
));
675 if (! changed
|| ! cleanup_cfg (CLEANUP_EXPENSIVE
))
679 /* If asked, remove notes from the blocks we'll update. */
680 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
681 count_or_remove_death_notes (blocks
, 1);
686 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
688 basic_block bb
= BASIC_BLOCK (i
);
690 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
691 propagate_block (bb
, tmp
, NULL
, NULL
, prop_flags
);
693 if (extent
== UPDATE_LIFE_LOCAL
)
694 verify_local_live_at_start (tmp
, bb
);
699 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
701 basic_block bb
= BASIC_BLOCK (i
);
703 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
704 propagate_block (bb
, tmp
, NULL
, NULL
, prop_flags
);
706 if (extent
== UPDATE_LIFE_LOCAL
)
707 verify_local_live_at_start (tmp
, bb
);
713 if (prop_flags
& PROP_REG_INFO
)
715 /* The only pseudos that are live at the beginning of the function
716 are those that were not set anywhere in the function. local-alloc
717 doesn't know how to handle these correctly, so mark them as not
718 local to any one basic block. */
719 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
720 FIRST_PSEUDO_REGISTER
, i
,
721 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
723 /* We have a problem with any pseudoreg that lives across the setjmp.
724 ANSI says that if a user variable does not change in value between
725 the setjmp and the longjmp, then the longjmp preserves it. This
726 includes longjmp from a place where the pseudo appears dead.
727 (In principle, the value still exists if it is in scope.)
728 If the pseudo goes in a hard reg, some other value may occupy
729 that hard reg where this pseudo is dead, thus clobbering the pseudo.
730 Conclusion: such a pseudo must not go in a hard reg. */
731 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
732 FIRST_PSEUDO_REGISTER
, i
,
734 if (regno_reg_rtx
[i
] != 0)
736 REG_LIVE_LENGTH (i
) = -1;
737 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
741 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
742 ? TV_LIFE_UPDATE
: TV_LIFE
);
745 /* Free the variables allocated by find_basic_blocks.
747 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
750 free_basic_block_vars (keep_head_end_p
)
753 if (! keep_head_end_p
)
755 if (basic_block_info
)
758 VARRAY_FREE (basic_block_info
);
762 ENTRY_BLOCK_PTR
->aux
= NULL
;
763 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
764 EXIT_BLOCK_PTR
->aux
= NULL
;
765 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
769 /* Delete any insns that copy a register to itself. */
772 delete_noop_moves (f
)
773 rtx f ATTRIBUTE_UNUSED
;
779 for (i
= 0; i
< n_basic_blocks
; i
++)
781 bb
= BASIC_BLOCK (i
);
782 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
784 next
= NEXT_INSN (insn
);
785 if (INSN_P (insn
) && noop_move_p (insn
))
789 /* If we're about to remove the first insn of a libcall
790 then move the libcall note to the next real insn and
791 update the retval note. */
792 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
793 && XEXP (note
, 0) != insn
)
795 rtx new_libcall_insn
= next_real_insn (insn
);
796 rtx retval_note
= find_reg_note (XEXP (note
, 0),
797 REG_RETVAL
, NULL_RTX
);
798 REG_NOTES (new_libcall_insn
)
799 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
800 REG_NOTES (new_libcall_insn
));
801 XEXP (retval_note
, 0) = new_libcall_insn
;
804 /* Do not call delete_insn here since that may change
805 the basic block boundaries which upsets some callers. */
806 PUT_CODE (insn
, NOTE
);
807 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
808 NOTE_SOURCE_FILE (insn
) = 0;
814 /* Delete any jump tables never referenced. We can't delete them at the
815 time of removing tablejump insn as they are referenced by the preceding
816 insns computing the destination, so we delay deleting and garbagecollect
817 them once life information is computed. */
819 delete_dead_jumptables ()
822 for (insn
= get_insns (); insn
; insn
= next
)
824 next
= NEXT_INSN (insn
);
825 if (GET_CODE (insn
) == CODE_LABEL
826 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
827 && GET_CODE (next
) == JUMP_INSN
828 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
829 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
832 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
833 delete_insn (NEXT_INSN (insn
));
835 next
= NEXT_INSN (next
);
840 /* Determine if the stack pointer is constant over the life of the function.
841 Only useful before prologues have been emitted. */
844 notice_stack_pointer_modification_1 (x
, pat
, data
)
846 rtx pat ATTRIBUTE_UNUSED
;
847 void *data ATTRIBUTE_UNUSED
;
849 if (x
== stack_pointer_rtx
850 /* The stack pointer is only modified indirectly as the result
851 of a push until later in flow. See the comments in rtl.texi
852 regarding Embedded Side-Effects on Addresses. */
853 || (GET_CODE (x
) == MEM
854 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
855 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
856 current_function_sp_is_unchanging
= 0;
860 notice_stack_pointer_modification (f
)
865 /* Assume that the stack pointer is unchanging if alloca hasn't
867 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
868 if (! current_function_sp_is_unchanging
)
871 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
875 /* Check if insn modifies the stack pointer. */
876 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
878 if (! current_function_sp_is_unchanging
)
884 /* Mark a register in SET. Hard registers in large modes get all
885 of their component registers set as well. */
892 regset set
= (regset
) xset
;
893 int regno
= REGNO (reg
);
895 if (GET_MODE (reg
) == BLKmode
)
898 SET_REGNO_REG_SET (set
, regno
);
899 if (regno
< FIRST_PSEUDO_REGISTER
)
901 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
903 SET_REGNO_REG_SET (set
, regno
+ n
);
907 /* Mark those regs which are needed at the end of the function as live
908 at the end of the last basic block. */
911 mark_regs_live_at_end (set
)
916 /* If exiting needs the right stack value, consider the stack pointer
917 live at the end of the function. */
918 if ((HAVE_epilogue
&& reload_completed
)
919 || ! EXIT_IGNORE_STACK
920 || (! FRAME_POINTER_REQUIRED
921 && ! current_function_calls_alloca
922 && flag_omit_frame_pointer
)
923 || current_function_sp_is_unchanging
)
925 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
928 /* Mark the frame pointer if needed at the end of the function. If
929 we end up eliminating it, it will be removed from the live list
930 of each basic block by reload. */
932 if (! reload_completed
|| frame_pointer_needed
)
934 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
935 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
936 /* If they are different, also mark the hard frame pointer as live. */
937 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
938 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
942 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
943 /* Many architectures have a GP register even without flag_pic.
944 Assume the pic register is not in use, or will be handled by
945 other means, if it is not fixed. */
946 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
947 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
948 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
951 /* Mark all global registers, and all registers used by the epilogue
952 as being live at the end of the function since they may be
953 referenced by our caller. */
954 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
955 if (global_regs
[i
] || EPILOGUE_USES (i
))
956 SET_REGNO_REG_SET (set
, i
);
958 if (HAVE_epilogue
&& reload_completed
)
960 /* Mark all call-saved registers that we actually used. */
961 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
962 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
963 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
964 SET_REGNO_REG_SET (set
, i
);
967 #ifdef EH_RETURN_DATA_REGNO
968 /* Mark the registers that will contain data for the handler. */
969 if (reload_completed
&& current_function_calls_eh_return
)
972 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
973 if (regno
== INVALID_REGNUM
)
975 SET_REGNO_REG_SET (set
, regno
);
978 #ifdef EH_RETURN_STACKADJ_RTX
979 if ((! HAVE_epilogue
|| ! reload_completed
)
980 && current_function_calls_eh_return
)
982 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
983 if (tmp
&& REG_P (tmp
))
987 #ifdef EH_RETURN_HANDLER_RTX
988 if ((! HAVE_epilogue
|| ! reload_completed
)
989 && current_function_calls_eh_return
)
991 rtx tmp
= EH_RETURN_HANDLER_RTX
;
992 if (tmp
&& REG_P (tmp
))
997 /* Mark function return value. */
998 diddle_return_value (mark_reg
, set
);
1001 /* Callback function for for_each_successor_phi. DATA is a regset.
1002 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1003 INSN, in the regset. */
1006 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1007 rtx insn ATTRIBUTE_UNUSED
;
1008 int dest_regno ATTRIBUTE_UNUSED
;
1012 regset live
= (regset
) data
;
1013 SET_REGNO_REG_SET (live
, src_regno
);
1017 /* Propagate global life info around the graph of basic blocks. Begin
1018 considering blocks with their corresponding bit set in BLOCKS_IN.
1019 If BLOCKS_IN is null, consider it the universal set.
1021 BLOCKS_OUT is set for every block that was changed. */
1024 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1025 sbitmap blocks_in
, blocks_out
;
1028 basic_block
*queue
, *qhead
, *qtail
, *qend
;
1029 regset tmp
, new_live_at_end
, call_used
;
1030 regset_head tmp_head
, call_used_head
;
1031 regset_head new_live_at_end_head
;
1034 tmp
= INITIALIZE_REG_SET (tmp_head
);
1035 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1036 call_used
= INITIALIZE_REG_SET (call_used_head
);
1038 /* Inconveniently, this is only readily available in hard reg set form. */
1039 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1040 if (call_used_regs
[i
])
1041 SET_REGNO_REG_SET (call_used
, i
);
1043 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1044 because the `head == tail' style test for an empty queue doesn't
1045 work with a full queue. */
1046 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1048 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1050 /* Queue the blocks set in the initial mask. Do this in reverse block
1051 number order so that we are more likely for the first round to do
1052 useful work. We use AUX non-null to flag that the block is queued. */
1055 /* Clear out the garbage that might be hanging out in bb->aux. */
1056 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1057 BASIC_BLOCK (i
)->aux
= NULL
;
1059 EXECUTE_IF_SET_IN_SBITMAP (blocks_in
, 0, i
,
1061 basic_block bb
= BASIC_BLOCK (i
);
1068 for (i
= 0; i
< n_basic_blocks
; ++i
)
1070 basic_block bb
= BASIC_BLOCK (i
);
1077 sbitmap_zero (blocks_out
);
1079 /* We work through the queue until there are no more blocks. What
1080 is live at the end of this block is precisely the union of what
1081 is live at the beginning of all its successors. So, we set its
1082 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1083 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1084 this block by walking through the instructions in this block in
1085 reverse order and updating as we go. If that changed
1086 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1087 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1089 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1090 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1091 must either be live at the end of the block, or used within the
1092 block. In the latter case, it will certainly never disappear
1093 from GLOBAL_LIVE_AT_START. In the former case, the register
1094 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1095 for one of the successor blocks. By induction, that cannot
1097 while (qhead
!= qtail
)
1099 int rescan
, changed
;
1108 /* Begin by propagating live_at_start from the successor blocks. */
1109 CLEAR_REG_SET (new_live_at_end
);
1110 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1112 basic_block sb
= e
->dest
;
1114 /* Call-clobbered registers die across exception and call edges. */
1115 /* ??? Abnormal call edges ignored for the moment, as this gets
1116 confused by sibling call edges, which crashes reg-stack. */
1117 if (e
->flags
& EDGE_EH
)
1119 bitmap_operation (tmp
, sb
->global_live_at_start
,
1120 call_used
, BITMAP_AND_COMPL
);
1121 IOR_REG_SET (new_live_at_end
, tmp
);
1124 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1127 /* The all-important stack pointer must always be live. */
1128 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1130 /* Before reload, there are a few registers that must be forced
1131 live everywhere -- which might not already be the case for
1132 blocks within infinite loops. */
1133 if (! reload_completed
)
1135 /* Any reference to any pseudo before reload is a potential
1136 reference of the frame pointer. */
1137 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1139 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1140 /* Pseudos with argument area equivalences may require
1141 reloading via the argument pointer. */
1142 if (fixed_regs
[ARG_POINTER_REGNUM
])
1143 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1146 /* Any constant, or pseudo with constant equivalences, may
1147 require reloading from memory using the pic register. */
1148 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1149 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1150 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1153 /* Regs used in phi nodes are not included in
1154 global_live_at_start, since they are live only along a
1155 particular edge. Set those regs that are live because of a
1156 phi node alternative corresponding to this particular block. */
1158 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1161 if (bb
== ENTRY_BLOCK_PTR
)
1163 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1167 /* On our first pass through this block, we'll go ahead and continue.
1168 Recognize first pass by local_set NULL. On subsequent passes, we
1169 get to skip out early if live_at_end wouldn't have changed. */
1171 if (bb
->local_set
== NULL
)
1173 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1174 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1179 /* If any bits were removed from live_at_end, we'll have to
1180 rescan the block. This wouldn't be necessary if we had
1181 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1182 local_live is really dependent on live_at_end. */
1183 CLEAR_REG_SET (tmp
);
1184 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1185 new_live_at_end
, BITMAP_AND_COMPL
);
1189 /* If any of the registers in the new live_at_end set are
1190 conditionally set in this basic block, we must rescan.
1191 This is because conditional lifetimes at the end of the
1192 block do not just take the live_at_end set into account,
1193 but also the liveness at the start of each successor
1194 block. We can miss changes in those sets if we only
1195 compare the new live_at_end against the previous one. */
1196 CLEAR_REG_SET (tmp
);
1197 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1198 bb
->cond_local_set
, BITMAP_AND
);
1203 /* Find the set of changed bits. Take this opportunity
1204 to notice that this set is empty and early out. */
1205 CLEAR_REG_SET (tmp
);
1206 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1207 new_live_at_end
, BITMAP_XOR
);
1211 /* If any of the changed bits overlap with local_set,
1212 we'll have to rescan the block. Detect overlap by
1213 the AND with ~local_set turning off bits. */
1214 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1219 /* Let our caller know that BB changed enough to require its
1220 death notes updated. */
1222 SET_BIT (blocks_out
, bb
->index
);
1226 /* Add to live_at_start the set of all registers in
1227 new_live_at_end that aren't in the old live_at_end. */
1229 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1231 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1233 changed
= bitmap_operation (bb
->global_live_at_start
,
1234 bb
->global_live_at_start
,
1241 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1243 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1244 into live_at_start. */
1245 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1246 bb
->cond_local_set
, flags
);
1248 /* If live_at start didn't change, no need to go farther. */
1249 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1252 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1255 /* Queue all predecessors of BB so that we may re-examine
1256 their live_at_end. */
1257 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1259 basic_block pb
= e
->src
;
1260 if (pb
->aux
== NULL
)
1271 FREE_REG_SET (new_live_at_end
);
1272 FREE_REG_SET (call_used
);
1276 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1278 basic_block bb
= BASIC_BLOCK (i
);
1279 FREE_REG_SET (bb
->local_set
);
1280 FREE_REG_SET (bb
->cond_local_set
);
1285 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1287 basic_block bb
= BASIC_BLOCK (i
);
1288 FREE_REG_SET (bb
->local_set
);
1289 FREE_REG_SET (bb
->cond_local_set
);
1297 /* This structure is used to pass parameters to an from the
1298 the function find_regno_partial(). It is used to pass in the
1299 register number we are looking, as well as to return any rtx
1303 unsigned regno_to_find
;
1305 } find_regno_partial_param
;
1308 /* Find the rtx for the reg numbers specified in 'data' if it is
1309 part of an expression which only uses part of the register. Return
1310 it in the structure passed in. */
1312 find_regno_partial (ptr
, data
)
1316 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1317 unsigned reg
= param
->regno_to_find
;
1318 param
->retval
= NULL_RTX
;
1320 if (*ptr
== NULL_RTX
)
1323 switch (GET_CODE (*ptr
))
1327 case STRICT_LOW_PART
:
1328 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1330 param
->retval
= XEXP (*ptr
, 0);
1336 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1337 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1339 param
->retval
= SUBREG_REG (*ptr
);
1351 /* Process all immediate successors of the entry block looking for pseudo
1352 registers which are live on entry. Find all of those whose first
1353 instance is a partial register reference of some kind, and initialize
1354 them to 0 after the entry block. This will prevent bit sets within
1355 registers whose value is unknown, and may contain some kind of sticky
1356 bits we don't want. */
1359 initialize_uninitialized_subregs ()
1363 int reg
, did_something
= 0;
1364 find_regno_partial_param param
;
1366 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1368 basic_block bb
= e
->dest
;
1369 regset map
= bb
->global_live_at_start
;
1370 EXECUTE_IF_SET_IN_REG_SET (map
,
1371 FIRST_PSEUDO_REGISTER
, reg
,
1373 int uid
= REGNO_FIRST_UID (reg
);
1376 /* Find an insn which mentions the register we are looking for.
1377 Its preferable to have an instance of the register's rtl since
1378 there may be various flags set which we need to duplicate.
1379 If we can't find it, its probably an automatic whose initial
1380 value doesn't matter, or hopefully something we don't care about. */
1381 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1385 /* Found the insn, now get the REG rtx, if we can. */
1386 param
.regno_to_find
= reg
;
1387 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1388 if (param
.retval
!= NULL_RTX
)
1390 insn
= gen_move_insn (param
.retval
,
1391 CONST0_RTX (GET_MODE (param
.retval
)));
1392 insert_insn_on_edge (insn
, e
);
1400 commit_edge_insertions ();
1401 return did_something
;
1405 /* Subroutines of life analysis. */
1407 /* Allocate the permanent data structures that represent the results
1408 of life analysis. Not static since used also for stupid life analysis. */
1411 allocate_bb_life_data ()
1415 for (i
= 0; i
< n_basic_blocks
; i
++)
1417 basic_block bb
= BASIC_BLOCK (i
);
1419 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1420 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1423 ENTRY_BLOCK_PTR
->global_live_at_end
1424 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1425 EXIT_BLOCK_PTR
->global_live_at_start
1426 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1428 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1432 allocate_reg_life_data ()
1436 max_regno
= max_reg_num ();
1438 /* Recalculate the register space, in case it has grown. Old style
1439 vector oriented regsets would set regset_{size,bytes} here also. */
1440 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1442 /* Reset all the data we'll collect in propagate_block and its
1444 for (i
= 0; i
< max_regno
; i
++)
1448 REG_N_DEATHS (i
) = 0;
1449 REG_N_CALLS_CROSSED (i
) = 0;
1450 REG_LIVE_LENGTH (i
) = 0;
1451 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1455 /* Delete dead instructions for propagate_block. */
1458 propagate_block_delete_insn (bb
, insn
)
1462 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1465 /* If the insn referred to a label, and that label was attached to
1466 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1467 pretty much mandatory to delete it, because the ADDR_VEC may be
1468 referencing labels that no longer exist.
1470 INSN may reference a deleted label, particularly when a jump
1471 table has been optimized into a direct jump. There's no
1472 real good way to fix up the reference to the deleted label
1473 when the label is deleted, so we just allow it here.
1475 After dead code elimination is complete, we do search for
1476 any REG_LABEL notes which reference deleted labels as a
1479 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1481 rtx label
= XEXP (inote
, 0);
1484 /* The label may be forced if it has been put in the constant
1485 pool. If that is the only use we must discard the table
1486 jump following it, but not the label itself. */
1487 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1488 && (next
= next_nonnote_insn (label
)) != NULL
1489 && GET_CODE (next
) == JUMP_INSN
1490 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1491 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1493 rtx pat
= PATTERN (next
);
1494 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1495 int len
= XVECLEN (pat
, diff_vec_p
);
1498 for (i
= 0; i
< len
; i
++)
1499 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1505 if (bb
->end
== insn
)
1509 purge_dead_edges (bb
);
1512 /* Delete dead libcalls for propagate_block. Return the insn
1513 before the libcall. */
1516 propagate_block_delete_libcall ( insn
, note
)
1519 rtx first
= XEXP (note
, 0);
1520 rtx before
= PREV_INSN (first
);
1522 delete_insn_chain (first
, insn
);
1526 /* Update the life-status of regs for one insn. Return the previous insn. */
1529 propagate_one_insn (pbi
, insn
)
1530 struct propagate_block_info
*pbi
;
1533 rtx prev
= PREV_INSN (insn
);
1534 int flags
= pbi
->flags
;
1535 int insn_is_dead
= 0;
1536 int libcall_is_dead
= 0;
1540 if (! INSN_P (insn
))
1543 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1544 if (flags
& PROP_SCAN_DEAD_CODE
)
1546 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1547 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1548 && libcall_dead_p (pbi
, note
, insn
));
1551 /* If an instruction consists of just dead store(s) on final pass,
1553 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1555 /* If we're trying to delete a prologue or epilogue instruction
1556 that isn't flagged as possibly being dead, something is wrong.
1557 But if we are keeping the stack pointer depressed, we might well
1558 be deleting insns that are used to compute the amount to update
1559 it by, so they are fine. */
1560 if (reload_completed
1561 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1562 && (TYPE_RETURNS_STACK_DEPRESSED
1563 (TREE_TYPE (current_function_decl
))))
1564 && (((HAVE_epilogue
|| HAVE_prologue
)
1565 && prologue_epilogue_contains (insn
))
1566 || (HAVE_sibcall_epilogue
1567 && sibcall_epilogue_contains (insn
)))
1568 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1569 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1571 /* Record sets. Do this even for dead instructions, since they
1572 would have killed the values if they hadn't been deleted. */
1573 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1575 /* CC0 is now known to be dead. Either this insn used it,
1576 in which case it doesn't anymore, or clobbered it,
1577 so the next insn can't use it. */
1580 if (libcall_is_dead
)
1581 prev
= propagate_block_delete_libcall ( insn
, note
);
1583 propagate_block_delete_insn (pbi
->bb
, insn
);
1588 /* See if this is an increment or decrement that can be merged into
1589 a following memory address. */
1592 rtx x
= single_set (insn
);
1594 /* Does this instruction increment or decrement a register? */
1595 if ((flags
& PROP_AUTOINC
)
1597 && GET_CODE (SET_DEST (x
)) == REG
1598 && (GET_CODE (SET_SRC (x
)) == PLUS
1599 || GET_CODE (SET_SRC (x
)) == MINUS
)
1600 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1601 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1602 /* Ok, look for a following memory ref we can combine with.
1603 If one is found, change the memory ref to a PRE_INC
1604 or PRE_DEC, cancel this insn, and return 1.
1605 Return 0 if nothing has been done. */
1606 && try_pre_increment_1 (pbi
, insn
))
1609 #endif /* AUTO_INC_DEC */
1611 CLEAR_REG_SET (pbi
->new_set
);
1613 /* If this is not the final pass, and this insn is copying the value of
1614 a library call and it's dead, don't scan the insns that perform the
1615 library call, so that the call's arguments are not marked live. */
1616 if (libcall_is_dead
)
1618 /* Record the death of the dest reg. */
1619 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1621 insn
= XEXP (note
, 0);
1622 return PREV_INSN (insn
);
1624 else if (GET_CODE (PATTERN (insn
)) == SET
1625 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1626 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1627 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1628 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1629 /* We have an insn to pop a constant amount off the stack.
1630 (Such insns use PLUS regardless of the direction of the stack,
1631 and any insn to adjust the stack by a constant is always a pop.)
1632 These insns, if not dead stores, have no effect on life. */
1636 /* Any regs live at the time of a call instruction must not go
1637 in a register clobbered by calls. Find all regs now live and
1638 record this for them. */
1640 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1641 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1642 { REG_N_CALLS_CROSSED (i
)++; });
1644 /* Record sets. Do this even for dead instructions, since they
1645 would have killed the values if they hadn't been deleted. */
1646 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1648 if (GET_CODE (insn
) == CALL_INSN
)
1654 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1655 cond
= COND_EXEC_TEST (PATTERN (insn
));
1657 /* Non-constant calls clobber memory. */
1658 if (! CONST_OR_PURE_CALL_P (insn
))
1660 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1661 pbi
->mem_set_list_len
= 0;
1664 /* There may be extra registers to be clobbered. */
1665 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1667 note
= XEXP (note
, 1))
1668 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1669 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1670 cond
, insn
, pbi
->flags
);
1672 /* Calls change all call-used and global registers. */
1673 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1674 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1676 /* We do not want REG_UNUSED notes for these registers. */
1677 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1679 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1683 /* If an insn doesn't use CC0, it becomes dead since we assume
1684 that every insn clobbers it. So show it dead here;
1685 mark_used_regs will set it live if it is referenced. */
1690 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1692 /* Sometimes we may have inserted something before INSN (such as a move)
1693 when we make an auto-inc. So ensure we will scan those insns. */
1695 prev
= PREV_INSN (insn
);
1698 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1704 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1705 cond
= COND_EXEC_TEST (PATTERN (insn
));
1707 /* Calls use their arguments. */
1708 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1710 note
= XEXP (note
, 1))
1711 if (GET_CODE (XEXP (note
, 0)) == USE
)
1712 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1715 /* The stack ptr is used (honorarily) by a CALL insn. */
1716 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1718 /* Calls may also reference any of the global registers,
1719 so they are made live. */
1720 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1722 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1727 /* On final pass, update counts of how many insns in which each reg
1729 if (flags
& PROP_REG_INFO
)
1730 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1731 { REG_LIVE_LENGTH (i
)++; });
1736 /* Initialize a propagate_block_info struct for public consumption.
1737 Note that the structure itself is opaque to this file, but that
1738 the user can use the regsets provided here. */
1740 struct propagate_block_info
*
1741 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1743 regset live
, local_set
, cond_local_set
;
1746 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1749 pbi
->reg_live
= live
;
1750 pbi
->mem_set_list
= NULL_RTX
;
1751 pbi
->mem_set_list_len
= 0;
1752 pbi
->local_set
= local_set
;
1753 pbi
->cond_local_set
= cond_local_set
;
1757 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1758 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1760 pbi
->reg_next_use
= NULL
;
1762 pbi
->new_set
= BITMAP_XMALLOC ();
1764 #ifdef HAVE_conditional_execution
1765 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1766 free_reg_cond_life_info
);
1767 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1769 /* If this block ends in a conditional branch, for each register live
1770 from one side of the branch and not the other, record the register
1771 as conditionally dead. */
1772 if (GET_CODE (bb
->end
) == JUMP_INSN
1773 && any_condjump_p (bb
->end
))
1775 regset_head diff_head
;
1776 regset diff
= INITIALIZE_REG_SET (diff_head
);
1777 basic_block bb_true
, bb_false
;
1778 rtx cond_true
, cond_false
, set_src
;
1781 /* Identify the successor blocks. */
1782 bb_true
= bb
->succ
->dest
;
1783 if (bb
->succ
->succ_next
!= NULL
)
1785 bb_false
= bb
->succ
->succ_next
->dest
;
1787 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1789 basic_block t
= bb_false
;
1793 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1798 /* This can happen with a conditional jump to the next insn. */
1799 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1802 /* Simplest way to do nothing. */
1806 /* Extract the condition from the branch. */
1807 set_src
= SET_SRC (pc_set (bb
->end
));
1808 cond_true
= XEXP (set_src
, 0);
1809 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1810 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1811 XEXP (cond_true
, 1));
1812 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1815 cond_false
= cond_true
;
1819 /* Compute which register lead different lives in the successors. */
1820 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1821 bb_false
->global_live_at_start
, BITMAP_XOR
))
1823 rtx reg
= XEXP (cond_true
, 0);
1825 if (GET_CODE (reg
) == SUBREG
)
1826 reg
= SUBREG_REG (reg
);
1828 if (GET_CODE (reg
) != REG
)
1831 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1833 /* For each such register, mark it conditionally dead. */
1834 EXECUTE_IF_SET_IN_REG_SET
1837 struct reg_cond_life_info
*rcli
;
1840 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1842 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1846 rcli
->condition
= cond
;
1847 rcli
->stores
= const0_rtx
;
1848 rcli
->orig_condition
= cond
;
1850 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1851 (splay_tree_value
) rcli
);
1855 FREE_REG_SET (diff
);
1859 /* If this block has no successors, any stores to the frame that aren't
1860 used later in the block are dead. So make a pass over the block
1861 recording any such that are made and show them dead at the end. We do
1862 a very conservative and simple job here. */
1864 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1865 && (TYPE_RETURNS_STACK_DEPRESSED
1866 (TREE_TYPE (current_function_decl
))))
1867 && (flags
& PROP_SCAN_DEAD_CODE
)
1868 && (bb
->succ
== NULL
1869 || (bb
->succ
->succ_next
== NULL
1870 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1871 && ! current_function_calls_eh_return
)))
1874 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1875 if (GET_CODE (insn
) == INSN
1876 && (set
= single_set (insn
))
1877 && GET_CODE (SET_DEST (set
)) == MEM
)
1879 rtx mem
= SET_DEST (set
);
1880 rtx canon_mem
= canon_rtx (mem
);
1882 /* This optimization is performed by faking a store to the
1883 memory at the end of the block. This doesn't work for
1884 unchanging memories because multiple stores to unchanging
1885 memory is illegal and alias analysis doesn't consider it. */
1886 if (RTX_UNCHANGING_P (canon_mem
))
1889 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1890 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1891 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1892 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1893 add_to_mem_set_list (pbi
, canon_mem
);
1900 /* Release a propagate_block_info struct. */
1903 free_propagate_block_info (pbi
)
1904 struct propagate_block_info
*pbi
;
1906 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1908 BITMAP_XFREE (pbi
->new_set
);
1910 #ifdef HAVE_conditional_execution
1911 splay_tree_delete (pbi
->reg_cond_dead
);
1912 BITMAP_XFREE (pbi
->reg_cond_reg
);
1915 if (pbi
->reg_next_use
)
1916 free (pbi
->reg_next_use
);
1921 /* Compute the registers live at the beginning of a basic block BB from
1922 those live at the end.
1924 When called, REG_LIVE contains those live at the end. On return, it
1925 contains those live at the beginning.
1927 LOCAL_SET, if non-null, will be set with all registers killed
1928 unconditionally by this basic block.
1929 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1930 killed conditionally by this basic block. If there is any unconditional
1931 set of a register, then the corresponding bit will be set in LOCAL_SET
1932 and cleared in COND_LOCAL_SET.
1933 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1934 case, the resulting set will be equal to the union of the two sets that
1935 would otherwise be computed.
1937 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1940 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
1944 regset cond_local_set
;
1947 struct propagate_block_info
*pbi
;
1951 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
1953 if (flags
& PROP_REG_INFO
)
1957 /* Process the regs live at the end of the block.
1958 Mark them as not local to any one basic block. */
1959 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
1960 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
1963 /* Scan the block an insn at a time from end to beginning. */
1966 for (insn
= bb
->end
;; insn
= prev
)
1968 /* If this is a call to `setjmp' et al, warn if any
1969 non-volatile datum is live. */
1970 if ((flags
& PROP_REG_INFO
)
1971 && GET_CODE (insn
) == CALL_INSN
1972 && find_reg_note (insn
, REG_SETJMP
, NULL
))
1973 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
1975 prev
= propagate_one_insn (pbi
, insn
);
1976 changed
|= NEXT_INSN (prev
) != insn
;
1978 if (insn
== bb
->head
)
1982 free_propagate_block_info (pbi
);
1987 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1988 (SET expressions whose destinations are registers dead after the insn).
1989 NEEDED is the regset that says which regs are alive after the insn.
1991 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1993 If X is the entire body of an insn, NOTES contains the reg notes
1994 pertaining to the insn. */
1997 insn_dead_p (pbi
, x
, call_ok
, notes
)
1998 struct propagate_block_info
*pbi
;
2001 rtx notes ATTRIBUTE_UNUSED
;
2003 enum rtx_code code
= GET_CODE (x
);
2006 /* As flow is invoked after combine, we must take existing AUTO_INC
2007 expressions into account. */
2008 for (; notes
; notes
= XEXP (notes
, 1))
2010 if (REG_NOTE_KIND (notes
) == REG_INC
)
2012 int regno
= REGNO (XEXP (notes
, 0));
2014 /* Don't delete insns to set global regs. */
2015 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2016 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2022 /* If setting something that's a reg or part of one,
2023 see if that register's altered value will be live. */
2027 rtx r
= SET_DEST (x
);
2030 if (GET_CODE (r
) == CC0
)
2031 return ! pbi
->cc0_live
;
2034 /* A SET that is a subroutine call cannot be dead. */
2035 if (GET_CODE (SET_SRC (x
)) == CALL
)
2041 /* Don't eliminate loads from volatile memory or volatile asms. */
2042 else if (volatile_refs_p (SET_SRC (x
)))
2045 if (GET_CODE (r
) == MEM
)
2049 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2052 canon_r
= canon_rtx (r
);
2054 /* Walk the set of memory locations we are currently tracking
2055 and see if one is an identical match to this memory location.
2056 If so, this memory write is dead (remember, we're walking
2057 backwards from the end of the block to the start). Since
2058 rtx_equal_p does not check the alias set or flags, we also
2059 must have the potential for them to conflict (anti_dependence). */
2060 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2061 if (anti_dependence (r
, XEXP (temp
, 0)))
2063 rtx mem
= XEXP (temp
, 0);
2065 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2066 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2067 <= GET_MODE_SIZE (GET_MODE (mem
))))
2071 /* Check if memory reference matches an auto increment. Only
2072 post increment/decrement or modify are valid. */
2073 if (GET_MODE (mem
) == GET_MODE (r
)
2074 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2075 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2076 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2077 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2078 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2085 while (GET_CODE (r
) == SUBREG
2086 || GET_CODE (r
) == STRICT_LOW_PART
2087 || GET_CODE (r
) == ZERO_EXTRACT
)
2090 if (GET_CODE (r
) == REG
)
2092 int regno
= REGNO (r
);
2095 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2098 /* If this is a hard register, verify that subsequent
2099 words are not needed. */
2100 if (regno
< FIRST_PSEUDO_REGISTER
)
2102 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2105 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2109 /* Don't delete insns to set global regs. */
2110 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2113 /* Make sure insns to set the stack pointer aren't deleted. */
2114 if (regno
== STACK_POINTER_REGNUM
)
2117 /* ??? These bits might be redundant with the force live bits
2118 in calculate_global_regs_live. We would delete from
2119 sequential sets; whether this actually affects real code
2120 for anything but the stack pointer I don't know. */
2121 /* Make sure insns to set the frame pointer aren't deleted. */
2122 if (regno
== FRAME_POINTER_REGNUM
2123 && (! reload_completed
|| frame_pointer_needed
))
2125 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2126 if (regno
== HARD_FRAME_POINTER_REGNUM
2127 && (! reload_completed
|| frame_pointer_needed
))
2131 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2132 /* Make sure insns to set arg pointer are never deleted
2133 (if the arg pointer isn't fixed, there will be a USE
2134 for it, so we can treat it normally). */
2135 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2139 /* Otherwise, the set is dead. */
2145 /* If performing several activities, insn is dead if each activity
2146 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2147 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2149 else if (code
== PARALLEL
)
2151 int i
= XVECLEN (x
, 0);
2153 for (i
--; i
>= 0; i
--)
2154 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2155 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2156 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2162 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2163 is not necessarily true for hard registers. */
2164 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2165 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2166 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2169 /* We do not check other CLOBBER or USE here. An insn consisting of just
2170 a CLOBBER or just a USE should not be deleted. */
2174 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2175 return 1 if the entire library call is dead.
2176 This is true if INSN copies a register (hard or pseudo)
2177 and if the hard return reg of the call insn is dead.
2178 (The caller should have tested the destination of the SET inside
2179 INSN already for death.)
2181 If this insn doesn't just copy a register, then we don't
2182 have an ordinary libcall. In that case, cse could not have
2183 managed to substitute the source for the dest later on,
2184 so we can assume the libcall is dead.
2186 PBI is the block info giving pseudoregs live before this insn.
2187 NOTE is the REG_RETVAL note of the insn. */
2190 libcall_dead_p (pbi
, note
, insn
)
2191 struct propagate_block_info
*pbi
;
2195 rtx x
= single_set (insn
);
2199 rtx r
= SET_SRC (x
);
2201 if (GET_CODE (r
) == REG
)
2203 rtx call
= XEXP (note
, 0);
2207 /* Find the call insn. */
2208 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2209 call
= NEXT_INSN (call
);
2211 /* If there is none, do nothing special,
2212 since ordinary death handling can understand these insns. */
2216 /* See if the hard reg holding the value is dead.
2217 If this is a PARALLEL, find the call within it. */
2218 call_pat
= PATTERN (call
);
2219 if (GET_CODE (call_pat
) == PARALLEL
)
2221 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2222 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2223 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2226 /* This may be a library call that is returning a value
2227 via invisible pointer. Do nothing special, since
2228 ordinary death handling can understand these insns. */
2232 call_pat
= XVECEXP (call_pat
, 0, i
);
2235 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2241 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2242 live at function entry. Don't count global register variables, variables
2243 in registers that can be used for function arg passing, or variables in
2244 fixed hard registers. */
2247 regno_uninitialized (regno
)
2250 if (n_basic_blocks
== 0
2251 || (regno
< FIRST_PSEUDO_REGISTER
2252 && (global_regs
[regno
]
2253 || fixed_regs
[regno
]
2254 || FUNCTION_ARG_REGNO_P (regno
))))
2257 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start
, regno
);
2260 /* 1 if register REGNO was alive at a place where `setjmp' was called
2261 and was set more than once or is an argument.
2262 Such regs may be clobbered by `longjmp'. */
2265 regno_clobbered_at_setjmp (regno
)
2268 if (n_basic_blocks
== 0)
2271 return ((REG_N_SETS (regno
) > 1
2272 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start
, regno
))
2273 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2276 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2277 maximal list size; look for overlaps in mode and select the largest. */
2279 add_to_mem_set_list (pbi
, mem
)
2280 struct propagate_block_info
*pbi
;
2285 /* We don't know how large a BLKmode store is, so we must not
2286 take them into consideration. */
2287 if (GET_MODE (mem
) == BLKmode
)
2290 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2292 rtx e
= XEXP (i
, 0);
2293 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2295 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2298 /* If we must store a copy of the mem, we can just modify
2299 the mode of the stored copy. */
2300 if (pbi
->flags
& PROP_AUTOINC
)
2301 PUT_MODE (e
, GET_MODE (mem
));
2310 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2313 /* Store a copy of mem, otherwise the address may be
2314 scrogged by find_auto_inc. */
2315 if (pbi
->flags
& PROP_AUTOINC
)
2316 mem
= shallow_copy_rtx (mem
);
2318 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2319 pbi
->mem_set_list_len
++;
2323 /* INSN references memory, possibly using autoincrement addressing modes.
2324 Find any entries on the mem_set_list that need to be invalidated due
2325 to an address change. */
2328 invalidate_mems_from_autoinc (pbi
, insn
)
2329 struct propagate_block_info
*pbi
;
2332 rtx note
= REG_NOTES (insn
);
2333 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2334 if (REG_NOTE_KIND (note
) == REG_INC
)
2335 invalidate_mems_from_set (pbi
, XEXP (note
, 0));
2338 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2341 invalidate_mems_from_set (pbi
, exp
)
2342 struct propagate_block_info
*pbi
;
2345 rtx temp
= pbi
->mem_set_list
;
2346 rtx prev
= NULL_RTX
;
2351 next
= XEXP (temp
, 1);
2352 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2354 /* Splice this entry out of the list. */
2356 XEXP (prev
, 1) = next
;
2358 pbi
->mem_set_list
= next
;
2359 free_EXPR_LIST_node (temp
);
2360 pbi
->mem_set_list_len
--;
2368 /* Process the registers that are set within X. Their bits are set to
2369 1 in the regset DEAD, because they are dead prior to this insn.
2371 If INSN is nonzero, it is the insn being processed.
2373 FLAGS is the set of operations to perform. */
2376 mark_set_regs (pbi
, x
, insn
)
2377 struct propagate_block_info
*pbi
;
2380 rtx cond
= NULL_RTX
;
2385 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2387 if (REG_NOTE_KIND (link
) == REG_INC
)
2388 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2389 (GET_CODE (x
) == COND_EXEC
2390 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2394 switch (code
= GET_CODE (x
))
2398 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2402 cond
= COND_EXEC_TEST (x
);
2403 x
= COND_EXEC_CODE (x
);
2410 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2412 rtx sub
= XVECEXP (x
, 0, i
);
2413 switch (code
= GET_CODE (sub
))
2416 if (cond
!= NULL_RTX
)
2419 cond
= COND_EXEC_TEST (sub
);
2420 sub
= COND_EXEC_CODE (sub
);
2421 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2427 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2442 /* Process a single set, which appears in INSN. REG (which may not
2443 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2444 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2445 If the set is conditional (because it appear in a COND_EXEC), COND
2446 will be the condition. */
2449 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2450 struct propagate_block_info
*pbi
;
2452 rtx reg
, cond
, insn
;
2455 int regno_first
= -1, regno_last
= -1;
2456 unsigned long not_dead
= 0;
2459 /* Modifying just one hardware register of a multi-reg value or just a
2460 byte field of a register does not mean the value from before this insn
2461 is now dead. Of course, if it was dead after it's unused now. */
2463 switch (GET_CODE (reg
))
2466 /* Some targets place small structures in registers for return values of
2467 functions. We have to detect this case specially here to get correct
2468 flow information. */
2469 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2470 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2471 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2477 case STRICT_LOW_PART
:
2478 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2480 reg
= XEXP (reg
, 0);
2481 while (GET_CODE (reg
) == SUBREG
2482 || GET_CODE (reg
) == ZERO_EXTRACT
2483 || GET_CODE (reg
) == SIGN_EXTRACT
2484 || GET_CODE (reg
) == STRICT_LOW_PART
);
2485 if (GET_CODE (reg
) == MEM
)
2487 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2491 regno_last
= regno_first
= REGNO (reg
);
2492 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2493 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2497 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2499 enum machine_mode outer_mode
= GET_MODE (reg
);
2500 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2502 /* Identify the range of registers affected. This is moderately
2503 tricky for hard registers. See alter_subreg. */
2505 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2506 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2508 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2511 regno_last
= (regno_first
2512 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2514 /* Since we've just adjusted the register number ranges, make
2515 sure REG matches. Otherwise some_was_live will be clear
2516 when it shouldn't have been, and we'll create incorrect
2517 REG_UNUSED notes. */
2518 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2522 /* If the number of words in the subreg is less than the number
2523 of words in the full register, we have a well-defined partial
2524 set. Otherwise the high bits are undefined.
2526 This is only really applicable to pseudos, since we just took
2527 care of multi-word hard registers. */
2528 if (((GET_MODE_SIZE (outer_mode
)
2529 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2530 < ((GET_MODE_SIZE (inner_mode
)
2531 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2532 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2535 reg
= SUBREG_REG (reg
);
2539 reg
= SUBREG_REG (reg
);
2546 /* If this set is a MEM, then it kills any aliased writes.
2547 If this set is a REG, then it kills any MEMs which use the reg. */
2548 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
2550 if (GET_CODE (reg
) == REG
)
2551 invalidate_mems_from_set (pbi
, reg
);
2553 /* If the memory reference had embedded side effects (autoincrement
2554 address modes. Then we may need to kill some entries on the
2556 if (insn
&& GET_CODE (reg
) == MEM
)
2557 invalidate_mems_from_autoinc (pbi
, insn
);
2559 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2560 /* ??? With more effort we could track conditional memory life. */
2562 /* There are no REG_INC notes for SP, so we can't assume we'll see
2563 everything that invalidates it. To be safe, don't eliminate any
2564 stores though SP; none of them should be redundant anyway. */
2565 && ! reg_mentioned_p (stack_pointer_rtx
, reg
))
2566 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2569 if (GET_CODE (reg
) == REG
2570 && ! (regno_first
== FRAME_POINTER_REGNUM
2571 && (! reload_completed
|| frame_pointer_needed
))
2572 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2573 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2574 && (! reload_completed
|| frame_pointer_needed
))
2576 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2577 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2581 int some_was_live
= 0, some_was_dead
= 0;
2583 for (i
= regno_first
; i
<= regno_last
; ++i
)
2585 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2588 /* Order of the set operation matters here since both
2589 sets may be the same. */
2590 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2591 if (cond
!= NULL_RTX
2592 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2593 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2595 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2597 if (code
!= CLOBBER
)
2598 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2600 some_was_live
|= needed_regno
;
2601 some_was_dead
|= ! needed_regno
;
2604 #ifdef HAVE_conditional_execution
2605 /* Consider conditional death in deciding that the register needs
2607 if (some_was_live
&& ! not_dead
2608 /* The stack pointer is never dead. Well, not strictly true,
2609 but it's very difficult to tell from here. Hopefully
2610 combine_stack_adjustments will fix up the most egregious
2612 && regno_first
!= STACK_POINTER_REGNUM
)
2614 for (i
= regno_first
; i
<= regno_last
; ++i
)
2615 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2616 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2620 /* Additional data to record if this is the final pass. */
2621 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2622 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2625 int blocknum
= pbi
->bb
->index
;
2628 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2630 y
= pbi
->reg_next_use
[regno_first
];
2632 /* The next use is no longer next, since a store intervenes. */
2633 for (i
= regno_first
; i
<= regno_last
; ++i
)
2634 pbi
->reg_next_use
[i
] = 0;
2637 if (flags
& PROP_REG_INFO
)
2639 for (i
= regno_first
; i
<= regno_last
; ++i
)
2641 /* Count (weighted) references, stores, etc. This counts a
2642 register twice if it is modified, but that is correct. */
2643 REG_N_SETS (i
) += 1;
2644 REG_N_REFS (i
) += 1;
2645 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2647 /* The insns where a reg is live are normally counted
2648 elsewhere, but we want the count to include the insn
2649 where the reg is set, and the normal counting mechanism
2650 would not count it. */
2651 REG_LIVE_LENGTH (i
) += 1;
2654 /* If this is a hard reg, record this function uses the reg. */
2655 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2657 for (i
= regno_first
; i
<= regno_last
; i
++)
2658 regs_ever_live
[i
] = 1;
2662 /* Keep track of which basic blocks each reg appears in. */
2663 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2664 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2665 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2666 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2670 if (! some_was_dead
)
2672 if (flags
& PROP_LOG_LINKS
)
2674 /* Make a logical link from the next following insn
2675 that uses this register, back to this insn.
2676 The following insns have already been processed.
2678 We don't build a LOG_LINK for hard registers containing
2679 in ASM_OPERANDs. If these registers get replaced,
2680 we might wind up changing the semantics of the insn,
2681 even if reload can make what appear to be valid
2682 assignments later. */
2683 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2684 && (regno_first
>= FIRST_PSEUDO_REGISTER
2685 || asm_noperands (PATTERN (y
)) < 0))
2686 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2691 else if (! some_was_live
)
2693 if (flags
& PROP_REG_INFO
)
2694 REG_N_DEATHS (regno_first
) += 1;
2696 if (flags
& PROP_DEATH_NOTES
)
2698 /* Note that dead stores have already been deleted
2699 when possible. If we get here, we have found a
2700 dead store that cannot be eliminated (because the
2701 same insn does something useful). Indicate this
2702 by marking the reg being set as dying here. */
2704 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2709 if (flags
& PROP_DEATH_NOTES
)
2711 /* This is a case where we have a multi-word hard register
2712 and some, but not all, of the words of the register are
2713 needed in subsequent insns. Write REG_UNUSED notes
2714 for those parts that were not needed. This case should
2717 for (i
= regno_first
; i
<= regno_last
; ++i
)
2718 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2720 = alloc_EXPR_LIST (REG_UNUSED
,
2721 gen_rtx_REG (reg_raw_mode
[i
], i
),
2727 /* Mark the register as being dead. */
2729 /* The stack pointer is never dead. Well, not strictly true,
2730 but it's very difficult to tell from here. Hopefully
2731 combine_stack_adjustments will fix up the most egregious
2733 && regno_first
!= STACK_POINTER_REGNUM
)
2735 for (i
= regno_first
; i
<= regno_last
; ++i
)
2736 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2737 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2740 else if (GET_CODE (reg
) == REG
)
2742 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2743 pbi
->reg_next_use
[regno_first
] = 0;
2746 /* If this is the last pass and this is a SCRATCH, show it will be dying
2747 here and count it. */
2748 else if (GET_CODE (reg
) == SCRATCH
)
2750 if (flags
& PROP_DEATH_NOTES
)
2752 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2756 #ifdef HAVE_conditional_execution
2757 /* Mark REGNO conditionally dead.
2758 Return true if the register is now unconditionally dead. */
2761 mark_regno_cond_dead (pbi
, regno
, cond
)
2762 struct propagate_block_info
*pbi
;
2766 /* If this is a store to a predicate register, the value of the
2767 predicate is changing, we don't know that the predicate as seen
2768 before is the same as that seen after. Flush all dependent
2769 conditions from reg_cond_dead. This will make all such
2770 conditionally live registers unconditionally live. */
2771 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2772 flush_reg_cond_reg (pbi
, regno
);
2774 /* If this is an unconditional store, remove any conditional
2775 life that may have existed. */
2776 if (cond
== NULL_RTX
)
2777 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2780 splay_tree_node node
;
2781 struct reg_cond_life_info
*rcli
;
2784 /* Otherwise this is a conditional set. Record that fact.
2785 It may have been conditionally used, or there may be a
2786 subsequent set with a complimentary condition. */
2788 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2791 /* The register was unconditionally live previously.
2792 Record the current condition as the condition under
2793 which it is dead. */
2794 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2795 rcli
->condition
= cond
;
2796 rcli
->stores
= cond
;
2797 rcli
->orig_condition
= const0_rtx
;
2798 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2799 (splay_tree_value
) rcli
);
2801 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2803 /* Not unconditionally dead. */
2808 /* The register was conditionally live previously.
2809 Add the new condition to the old. */
2810 rcli
= (struct reg_cond_life_info
*) node
->value
;
2811 ncond
= rcli
->condition
;
2812 ncond
= ior_reg_cond (ncond
, cond
, 1);
2813 if (rcli
->stores
== const0_rtx
)
2814 rcli
->stores
= cond
;
2815 else if (rcli
->stores
!= const1_rtx
)
2816 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2818 /* If the register is now unconditionally dead, remove the entry
2819 in the splay_tree. A register is unconditionally dead if the
2820 dead condition ncond is true. A register is also unconditionally
2821 dead if the sum of all conditional stores is an unconditional
2822 store (stores is true), and the dead condition is identically the
2823 same as the original dead condition initialized at the end of
2824 the block. This is a pointer compare, not an rtx_equal_p
2826 if (ncond
== const1_rtx
2827 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2828 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2831 rcli
->condition
= ncond
;
2833 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2835 /* Not unconditionally dead. */
2844 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2847 free_reg_cond_life_info (value
)
2848 splay_tree_value value
;
2850 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2854 /* Helper function for flush_reg_cond_reg. */
2857 flush_reg_cond_reg_1 (node
, data
)
2858 splay_tree_node node
;
2861 struct reg_cond_life_info
*rcli
;
2862 int *xdata
= (int *) data
;
2863 unsigned int regno
= xdata
[0];
2865 /* Don't need to search if last flushed value was farther on in
2866 the in-order traversal. */
2867 if (xdata
[1] >= (int) node
->key
)
2870 /* Splice out portions of the expression that refer to regno. */
2871 rcli
= (struct reg_cond_life_info
*) node
->value
;
2872 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2873 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2874 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2876 /* If the entire condition is now false, signal the node to be removed. */
2877 if (rcli
->condition
== const0_rtx
)
2879 xdata
[1] = node
->key
;
2882 else if (rcli
->condition
== const1_rtx
)
2888 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2891 flush_reg_cond_reg (pbi
, regno
)
2892 struct propagate_block_info
*pbi
;
2899 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2900 flush_reg_cond_reg_1
, pair
) == -1)
2901 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
2903 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
2906 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2907 For ior/and, the ADD flag determines whether we want to add the new
2908 condition X to the old one unconditionally. If it is zero, we will
2909 only return a new expression if X allows us to simplify part of
2910 OLD, otherwise we return NULL to the caller.
2911 If ADD is nonzero, we will return a new condition in all cases. The
2912 toplevel caller of one of these functions should always pass 1 for
2916 ior_reg_cond (old
, x
, add
)
2922 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
2924 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
2925 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
2926 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2928 if (GET_CODE (x
) == GET_CODE (old
)
2929 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
2933 return gen_rtx_IOR (0, old
, x
);
2936 switch (GET_CODE (old
))
2939 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
2940 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
2941 if (op0
!= NULL
|| op1
!= NULL
)
2943 if (op0
== const0_rtx
)
2944 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
2945 if (op1
== const0_rtx
)
2946 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
2947 if (op0
== const1_rtx
|| op1
== const1_rtx
)
2950 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
2951 else if (rtx_equal_p (x
, op0
))
2952 /* (x | A) | x ~ (x | A). */
2955 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
2956 else if (rtx_equal_p (x
, op1
))
2957 /* (A | x) | x ~ (A | x). */
2959 return gen_rtx_IOR (0, op0
, op1
);
2963 return gen_rtx_IOR (0, old
, x
);
2966 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
2967 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
2968 if (op0
!= NULL
|| op1
!= NULL
)
2970 if (op0
== const1_rtx
)
2971 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
2972 if (op1
== const1_rtx
)
2973 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
2974 if (op0
== const0_rtx
|| op1
== const0_rtx
)
2977 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
2978 else if (rtx_equal_p (x
, op0
))
2979 /* (x & A) | x ~ x. */
2982 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
2983 else if (rtx_equal_p (x
, op1
))
2984 /* (A & x) | x ~ x. */
2986 return gen_rtx_AND (0, op0
, op1
);
2990 return gen_rtx_IOR (0, old
, x
);
2993 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
2995 return not_reg_cond (op0
);
2998 return gen_rtx_IOR (0, old
, x
);
3009 enum rtx_code x_code
;
3011 if (x
== const0_rtx
)
3013 else if (x
== const1_rtx
)
3015 x_code
= GET_CODE (x
);
3018 if (GET_RTX_CLASS (x_code
) == '<'
3019 && GET_CODE (XEXP (x
, 0)) == REG
)
3021 if (XEXP (x
, 1) != const0_rtx
)
3024 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3025 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3027 return gen_rtx_NOT (0, x
);
3031 and_reg_cond (old
, x
, add
)
3037 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3039 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3040 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3041 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3043 if (GET_CODE (x
) == GET_CODE (old
)
3044 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3048 return gen_rtx_AND (0, old
, x
);
3051 switch (GET_CODE (old
))
3054 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3055 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3056 if (op0
!= NULL
|| op1
!= NULL
)
3058 if (op0
== const0_rtx
)
3059 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3060 if (op1
== const0_rtx
)
3061 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3062 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3065 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3066 else if (rtx_equal_p (x
, op0
))
3067 /* (x | A) & x ~ x. */
3070 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3071 else if (rtx_equal_p (x
, op1
))
3072 /* (A | x) & x ~ x. */
3074 return gen_rtx_IOR (0, op0
, op1
);
3078 return gen_rtx_AND (0, old
, x
);
3081 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3082 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3083 if (op0
!= NULL
|| op1
!= NULL
)
3085 if (op0
== const1_rtx
)
3086 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3087 if (op1
== const1_rtx
)
3088 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3089 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3092 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3093 else if (rtx_equal_p (x
, op0
))
3094 /* (x & A) & x ~ (x & A). */
3097 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3098 else if (rtx_equal_p (x
, op1
))
3099 /* (A & x) & x ~ (A & x). */
3101 return gen_rtx_AND (0, op0
, op1
);
3105 return gen_rtx_AND (0, old
, x
);
3108 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3110 return not_reg_cond (op0
);
3113 return gen_rtx_AND (0, old
, x
);
3120 /* Given a condition X, remove references to reg REGNO and return the
3121 new condition. The removal will be done so that all conditions
3122 involving REGNO are considered to evaluate to false. This function
3123 is used when the value of REGNO changes. */
3126 elim_reg_cond (x
, regno
)
3132 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3134 if (REGNO (XEXP (x
, 0)) == regno
)
3139 switch (GET_CODE (x
))
3142 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3143 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3144 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3146 if (op0
== const1_rtx
)
3148 if (op1
== const1_rtx
)
3150 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3152 return gen_rtx_AND (0, op0
, op1
);
3155 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3156 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3157 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3159 if (op0
== const0_rtx
)
3161 if (op1
== const0_rtx
)
3163 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3165 return gen_rtx_IOR (0, op0
, op1
);
3168 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3169 if (op0
== const0_rtx
)
3171 if (op0
== const1_rtx
)
3173 if (op0
!= XEXP (x
, 0))
3174 return not_reg_cond (op0
);
3181 #endif /* HAVE_conditional_execution */
3185 /* Try to substitute the auto-inc expression INC as the address inside
3186 MEM which occurs in INSN. Currently, the address of MEM is an expression
3187 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3188 that has a single set whose source is a PLUS of INCR_REG and something
3192 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3193 struct propagate_block_info
*pbi
;
3194 rtx inc
, insn
, mem
, incr
, incr_reg
;
3196 int regno
= REGNO (incr_reg
);
3197 rtx set
= single_set (incr
);
3198 rtx q
= SET_DEST (set
);
3199 rtx y
= SET_SRC (set
);
3200 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3202 /* Make sure this reg appears only once in this insn. */
3203 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3206 if (dead_or_set_p (incr
, incr_reg
)
3207 /* Mustn't autoinc an eliminable register. */
3208 && (regno
>= FIRST_PSEUDO_REGISTER
3209 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3211 /* This is the simple case. Try to make the auto-inc. If
3212 we can't, we are done. Otherwise, we will do any
3213 needed updates below. */
3214 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3217 else if (GET_CODE (q
) == REG
3218 /* PREV_INSN used here to check the semi-open interval
3220 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3221 /* We must also check for sets of q as q may be
3222 a call clobbered hard register and there may
3223 be a call between PREV_INSN (insn) and incr. */
3224 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3226 /* We have *p followed sometime later by q = p+size.
3227 Both p and q must be live afterward,
3228 and q is not used between INSN and its assignment.
3229 Change it to q = p, ...*q..., q = q+size.
3230 Then fall into the usual case. */
3234 emit_move_insn (q
, incr_reg
);
3235 insns
= get_insns ();
3238 /* If we can't make the auto-inc, or can't make the
3239 replacement into Y, exit. There's no point in making
3240 the change below if we can't do the auto-inc and doing
3241 so is not correct in the pre-inc case. */
3244 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3245 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3246 if (! apply_change_group ())
3249 /* We now know we'll be doing this change, so emit the
3250 new insn(s) and do the updates. */
3251 emit_insns_before (insns
, insn
);
3253 if (pbi
->bb
->head
== insn
)
3254 pbi
->bb
->head
= insns
;
3256 /* INCR will become a NOTE and INSN won't contain a
3257 use of INCR_REG. If a use of INCR_REG was just placed in
3258 the insn before INSN, make that the next use.
3259 Otherwise, invalidate it. */
3260 if (GET_CODE (PREV_INSN (insn
)) == INSN
3261 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3262 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3263 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3265 pbi
->reg_next_use
[regno
] = 0;
3270 /* REGNO is now used in INCR which is below INSN, but
3271 it previously wasn't live here. If we don't mark
3272 it as live, we'll put a REG_DEAD note for it
3273 on this insn, which is incorrect. */
3274 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3276 /* If there are any calls between INSN and INCR, show
3277 that REGNO now crosses them. */
3278 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3279 if (GET_CODE (temp
) == CALL_INSN
)
3280 REG_N_CALLS_CROSSED (regno
)++;
3282 /* Invalidate alias info for Q since we just changed its value. */
3283 clear_reg_alias_info (q
);
3288 /* If we haven't returned, it means we were able to make the
3289 auto-inc, so update the status. First, record that this insn
3290 has an implicit side effect. */
3292 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3294 /* Modify the old increment-insn to simply copy
3295 the already-incremented value of our register. */
3296 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3299 /* If that makes it a no-op (copying the register into itself) delete
3300 it so it won't appear to be a "use" and a "set" of this
3302 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3304 /* If the original source was dead, it's dead now. */
3307 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3309 remove_note (incr
, note
);
3310 if (XEXP (note
, 0) != incr_reg
)
3311 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3314 PUT_CODE (incr
, NOTE
);
3315 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3316 NOTE_SOURCE_FILE (incr
) = 0;
3319 if (regno
>= FIRST_PSEUDO_REGISTER
)
3321 /* Count an extra reference to the reg. When a reg is
3322 incremented, spilling it is worse, so we want to make
3323 that less likely. */
3324 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3326 /* Count the increment as a setting of the register,
3327 even though it isn't a SET in rtl. */
3328 REG_N_SETS (regno
)++;
3332 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3336 find_auto_inc (pbi
, x
, insn
)
3337 struct propagate_block_info
*pbi
;
3341 rtx addr
= XEXP (x
, 0);
3342 HOST_WIDE_INT offset
= 0;
3343 rtx set
, y
, incr
, inc_val
;
3345 int size
= GET_MODE_SIZE (GET_MODE (x
));
3347 if (GET_CODE (insn
) == JUMP_INSN
)
3350 /* Here we detect use of an index register which might be good for
3351 postincrement, postdecrement, preincrement, or predecrement. */
3353 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3354 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3356 if (GET_CODE (addr
) != REG
)
3359 regno
= REGNO (addr
);
3361 /* Is the next use an increment that might make auto-increment? */
3362 incr
= pbi
->reg_next_use
[regno
];
3363 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3365 set
= single_set (incr
);
3366 if (set
== 0 || GET_CODE (set
) != SET
)
3370 if (GET_CODE (y
) != PLUS
)
3373 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3374 inc_val
= XEXP (y
, 1);
3375 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3376 inc_val
= XEXP (y
, 0);
3380 if (GET_CODE (inc_val
) == CONST_INT
)
3382 if (HAVE_POST_INCREMENT
3383 && (INTVAL (inc_val
) == size
&& offset
== 0))
3384 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3386 else if (HAVE_POST_DECREMENT
3387 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3388 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3390 else if (HAVE_PRE_INCREMENT
3391 && (INTVAL (inc_val
) == size
&& offset
== size
))
3392 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3394 else if (HAVE_PRE_DECREMENT
3395 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3396 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3398 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3399 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3400 gen_rtx_PLUS (Pmode
,
3403 insn
, x
, incr
, addr
);
3405 else if (GET_CODE (inc_val
) == REG
3406 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3410 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3411 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3412 gen_rtx_PLUS (Pmode
,
3415 insn
, x
, incr
, addr
);
3419 #endif /* AUTO_INC_DEC */
3422 mark_used_reg (pbi
, reg
, cond
, insn
)
3423 struct propagate_block_info
*pbi
;
3425 rtx cond ATTRIBUTE_UNUSED
;
3428 unsigned int regno_first
, regno_last
, i
;
3429 int some_was_live
, some_was_dead
, some_not_set
;
3431 regno_last
= regno_first
= REGNO (reg
);
3432 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3433 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3435 /* Find out if any of this register is live after this instruction. */
3436 some_was_live
= some_was_dead
= 0;
3437 for (i
= regno_first
; i
<= regno_last
; ++i
)
3439 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3440 some_was_live
|= needed_regno
;
3441 some_was_dead
|= ! needed_regno
;
3444 /* Find out if any of the register was set this insn. */
3446 for (i
= regno_first
; i
<= regno_last
; ++i
)
3447 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3449 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3451 /* Record where each reg is used, so when the reg is set we know
3452 the next insn that uses it. */
3453 pbi
->reg_next_use
[regno_first
] = insn
;
3456 if (pbi
->flags
& PROP_REG_INFO
)
3458 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3460 /* If this is a register we are going to try to eliminate,
3461 don't mark it live here. If we are successful in
3462 eliminating it, it need not be live unless it is used for
3463 pseudos, in which case it will have been set live when it
3464 was allocated to the pseudos. If the register will not
3465 be eliminated, reload will set it live at that point.
3467 Otherwise, record that this function uses this register. */
3468 /* ??? The PPC backend tries to "eliminate" on the pic
3469 register to itself. This should be fixed. In the mean
3470 time, hack around it. */
3472 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3473 && (regno_first
== FRAME_POINTER_REGNUM
3474 || regno_first
== ARG_POINTER_REGNUM
)))
3475 for (i
= regno_first
; i
<= regno_last
; ++i
)
3476 regs_ever_live
[i
] = 1;
3480 /* Keep track of which basic block each reg appears in. */
3482 int blocknum
= pbi
->bb
->index
;
3483 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3484 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3485 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3486 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3488 /* Count (weighted) number of uses of each reg. */
3489 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3490 REG_N_REFS (regno_first
)++;
3494 /* Record and count the insns in which a reg dies. If it is used in
3495 this insn and was dead below the insn then it dies in this insn.
3496 If it was set in this insn, we do not make a REG_DEAD note;
3497 likewise if we already made such a note. */
3498 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3502 /* Check for the case where the register dying partially
3503 overlaps the register set by this insn. */
3504 if (regno_first
!= regno_last
)
3505 for (i
= regno_first
; i
<= regno_last
; ++i
)
3506 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3508 /* If none of the words in X is needed, make a REG_DEAD note.
3509 Otherwise, we must make partial REG_DEAD notes. */
3510 if (! some_was_live
)
3512 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3513 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3515 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3517 if (pbi
->flags
& PROP_REG_INFO
)
3518 REG_N_DEATHS (regno_first
)++;
3522 /* Don't make a REG_DEAD note for a part of a register
3523 that is set in the insn. */
3524 for (i
= regno_first
; i
<= regno_last
; ++i
)
3525 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3526 && ! dead_or_set_regno_p (insn
, i
))
3528 = alloc_EXPR_LIST (REG_DEAD
,
3529 gen_rtx_REG (reg_raw_mode
[i
], i
),
3534 /* Mark the register as being live. */
3535 for (i
= regno_first
; i
<= regno_last
; ++i
)
3537 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3539 #ifdef HAVE_conditional_execution
3540 /* If this is a conditional use, record that fact. If it is later
3541 conditionally set, we'll know to kill the register. */
3542 if (cond
!= NULL_RTX
)
3544 splay_tree_node node
;
3545 struct reg_cond_life_info
*rcli
;
3550 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3553 /* The register was unconditionally live previously.
3554 No need to do anything. */
3558 /* The register was conditionally live previously.
3559 Subtract the new life cond from the old death cond. */
3560 rcli
= (struct reg_cond_life_info
*) node
->value
;
3561 ncond
= rcli
->condition
;
3562 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3564 /* If the register is now unconditionally live,
3565 remove the entry in the splay_tree. */
3566 if (ncond
== const0_rtx
)
3567 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3570 rcli
->condition
= ncond
;
3571 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3572 REGNO (XEXP (cond
, 0)));
3578 /* The register was not previously live at all. Record
3579 the condition under which it is still dead. */
3580 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3581 rcli
->condition
= not_reg_cond (cond
);
3582 rcli
->stores
= const0_rtx
;
3583 rcli
->orig_condition
= const0_rtx
;
3584 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3585 (splay_tree_value
) rcli
);
3587 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3590 else if (some_was_live
)
3592 /* The register may have been conditionally live previously, but
3593 is now unconditionally live. Remove it from the conditionally
3594 dead list, so that a conditional set won't cause us to think
3596 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3602 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3603 This is done assuming the registers needed from X are those that
3604 have 1-bits in PBI->REG_LIVE.
3606 INSN is the containing instruction. If INSN is dead, this function
3610 mark_used_regs (pbi
, x
, cond
, insn
)
3611 struct propagate_block_info
*pbi
;
3616 int flags
= pbi
->flags
;
3619 code
= GET_CODE (x
);
3639 /* If we are clobbering a MEM, mark any registers inside the address
3641 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3642 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3646 /* Don't bother watching stores to mems if this is not the
3647 final pass. We'll not be deleting dead stores this round. */
3648 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
3650 /* Invalidate the data for the last MEM stored, but only if MEM is
3651 something that can be stored into. */
3652 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3653 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3654 /* Needn't clear the memory set list. */
3658 rtx temp
= pbi
->mem_set_list
;
3659 rtx prev
= NULL_RTX
;
3664 next
= XEXP (temp
, 1);
3665 if (anti_dependence (XEXP (temp
, 0), x
))
3667 /* Splice temp out of the list. */
3669 XEXP (prev
, 1) = next
;
3671 pbi
->mem_set_list
= next
;
3672 free_EXPR_LIST_node (temp
);
3673 pbi
->mem_set_list_len
--;
3681 /* If the memory reference had embedded side effects (autoincrement
3682 address modes. Then we may need to kill some entries on the
3685 invalidate_mems_from_autoinc (pbi
, insn
);
3689 if (flags
& PROP_AUTOINC
)
3690 find_auto_inc (pbi
, x
, insn
);
3695 #ifdef CLASS_CANNOT_CHANGE_MODE
3696 if (GET_CODE (SUBREG_REG (x
)) == REG
3697 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3698 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3699 GET_MODE (SUBREG_REG (x
))))
3700 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3703 /* While we're here, optimize this case. */
3705 if (GET_CODE (x
) != REG
)
3710 /* See a register other than being set => mark it as needed. */
3711 mark_used_reg (pbi
, x
, cond
, insn
);
3716 rtx testreg
= SET_DEST (x
);
3719 /* If storing into MEM, don't show it as being used. But do
3720 show the address as being used. */
3721 if (GET_CODE (testreg
) == MEM
)
3724 if (flags
& PROP_AUTOINC
)
3725 find_auto_inc (pbi
, testreg
, insn
);
3727 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3728 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3732 /* Storing in STRICT_LOW_PART is like storing in a reg
3733 in that this SET might be dead, so ignore it in TESTREG.
3734 but in some other ways it is like using the reg.
3736 Storing in a SUBREG or a bit field is like storing the entire
3737 register in that if the register's value is not used
3738 then this SET is not needed. */
3739 while (GET_CODE (testreg
) == STRICT_LOW_PART
3740 || GET_CODE (testreg
) == ZERO_EXTRACT
3741 || GET_CODE (testreg
) == SIGN_EXTRACT
3742 || GET_CODE (testreg
) == SUBREG
)
3744 #ifdef CLASS_CANNOT_CHANGE_MODE
3745 if (GET_CODE (testreg
) == SUBREG
3746 && GET_CODE (SUBREG_REG (testreg
)) == REG
3747 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3748 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3749 GET_MODE (testreg
)))
3750 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3753 /* Modifying a single register in an alternate mode
3754 does not use any of the old value. But these other
3755 ways of storing in a register do use the old value. */
3756 if (GET_CODE (testreg
) == SUBREG
3757 && !((REG_BYTES (SUBREG_REG (testreg
))
3758 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3759 > (REG_BYTES (testreg
)
3760 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3765 testreg
= XEXP (testreg
, 0);
3768 /* If this is a store into a register or group of registers,
3769 recursively scan the value being stored. */
3771 if ((GET_CODE (testreg
) == PARALLEL
3772 && GET_MODE (testreg
) == BLKmode
)
3773 || (GET_CODE (testreg
) == REG
3774 && (regno
= REGNO (testreg
),
3775 ! (regno
== FRAME_POINTER_REGNUM
3776 && (! reload_completed
|| frame_pointer_needed
)))
3777 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3778 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3779 && (! reload_completed
|| frame_pointer_needed
))
3781 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3782 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3787 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3788 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3795 case UNSPEC_VOLATILE
:
3799 /* Traditional and volatile asm instructions must be considered to use
3800 and clobber all hard registers, all pseudo-registers and all of
3801 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3803 Consider for instance a volatile asm that changes the fpu rounding
3804 mode. An insn should not be moved across this even if it only uses
3805 pseudo-regs because it might give an incorrectly rounded result.
3807 ?!? Unfortunately, marking all hard registers as live causes massive
3808 problems for the register allocator and marking all pseudos as live
3809 creates mountains of uninitialized variable warnings.
3811 So for now, just clear the memory set list and mark any regs
3812 we can find in ASM_OPERANDS as used. */
3813 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3815 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3816 pbi
->mem_set_list_len
= 0;
3819 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3820 We can not just fall through here since then we would be confused
3821 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3822 traditional asms unlike their normal usage. */
3823 if (code
== ASM_OPERANDS
)
3827 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3828 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3834 if (cond
!= NULL_RTX
)
3837 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3839 cond
= COND_EXEC_TEST (x
);
3840 x
= COND_EXEC_CODE (x
);
3844 /* We _do_not_ want to scan operands of phi nodes. Operands of
3845 a phi function are evaluated only when control reaches this
3846 block along a particular edge. Therefore, regs that appear
3847 as arguments to phi should not be added to the global live at
3855 /* Recursively scan the operands of this expression. */
3858 const char * const fmt
= GET_RTX_FORMAT (code
);
3861 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3865 /* Tail recursive case: save a function call level. */
3871 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3873 else if (fmt
[i
] == 'E')
3876 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3877 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3886 try_pre_increment_1 (pbi
, insn
)
3887 struct propagate_block_info
*pbi
;
3890 /* Find the next use of this reg. If in same basic block,
3891 make it do pre-increment or pre-decrement if appropriate. */
3892 rtx x
= single_set (insn
);
3893 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3894 * INTVAL (XEXP (SET_SRC (x
), 1)));
3895 int regno
= REGNO (SET_DEST (x
));
3896 rtx y
= pbi
->reg_next_use
[regno
];
3898 && SET_DEST (x
) != stack_pointer_rtx
3899 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
3900 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3901 mode would be better. */
3902 && ! dead_or_set_p (y
, SET_DEST (x
))
3903 && try_pre_increment (y
, SET_DEST (x
), amount
))
3905 /* We have found a suitable auto-increment and already changed
3906 insn Y to do it. So flush this increment instruction. */
3907 propagate_block_delete_insn (pbi
->bb
, insn
);
3909 /* Count a reference to this reg for the increment insn we are
3910 deleting. When a reg is incremented, spilling it is worse,
3911 so we want to make that less likely. */
3912 if (regno
>= FIRST_PSEUDO_REGISTER
)
3914 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3915 REG_N_SETS (regno
)++;
3918 /* Flush any remembered memories depending on the value of
3919 the incremented register. */
3920 invalidate_mems_from_set (pbi
, SET_DEST (x
));
3927 /* Try to change INSN so that it does pre-increment or pre-decrement
3928 addressing on register REG in order to add AMOUNT to REG.
3929 AMOUNT is negative for pre-decrement.
3930 Returns 1 if the change could be made.
3931 This checks all about the validity of the result of modifying INSN. */
3934 try_pre_increment (insn
, reg
, amount
)
3936 HOST_WIDE_INT amount
;
3940 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3941 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3943 /* Nonzero if we can try to make a post-increment or post-decrement.
3944 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3945 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3946 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3949 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3952 /* From the sign of increment, see which possibilities are conceivable
3953 on this target machine. */
3954 if (HAVE_PRE_INCREMENT
&& amount
> 0)
3956 if (HAVE_POST_INCREMENT
&& amount
> 0)
3959 if (HAVE_PRE_DECREMENT
&& amount
< 0)
3961 if (HAVE_POST_DECREMENT
&& amount
< 0)
3964 if (! (pre_ok
|| post_ok
))
3967 /* It is not safe to add a side effect to a jump insn
3968 because if the incremented register is spilled and must be reloaded
3969 there would be no way to store the incremented value back in memory. */
3971 if (GET_CODE (insn
) == JUMP_INSN
)
3976 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
3977 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
3979 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
3983 if (use
== 0 || use
== (rtx
) (size_t) 1)
3986 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
3989 /* See if this combination of instruction and addressing mode exists. */
3990 if (! validate_change (insn
, &XEXP (use
, 0),
3991 gen_rtx_fmt_e (amount
> 0
3992 ? (do_post
? POST_INC
: PRE_INC
)
3993 : (do_post
? POST_DEC
: PRE_DEC
),
3997 /* Record that this insn now has an implicit side effect on X. */
3998 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4002 #endif /* AUTO_INC_DEC */
4004 /* Find the place in the rtx X where REG is used as a memory address.
4005 Return the MEM rtx that so uses it.
4006 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4007 (plus REG (const_int PLUSCONST)).
4009 If such an address does not appear, return 0.
4010 If REG appears more than once, or is used other than in such an address,
4014 find_use_as_address (x
, reg
, plusconst
)
4017 HOST_WIDE_INT plusconst
;
4019 enum rtx_code code
= GET_CODE (x
);
4020 const char * const fmt
= GET_RTX_FORMAT (code
);
4025 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4028 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4029 && XEXP (XEXP (x
, 0), 0) == reg
4030 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4031 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4034 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4036 /* If REG occurs inside a MEM used in a bit-field reference,
4037 that is unacceptable. */
4038 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4039 return (rtx
) (size_t) 1;
4043 return (rtx
) (size_t) 1;
4045 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4049 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4053 return (rtx
) (size_t) 1;
4055 else if (fmt
[i
] == 'E')
4058 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4060 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4064 return (rtx
) (size_t) 1;
4072 /* Write information about registers and basic blocks into FILE.
4073 This is part of making a debugging dump. */
4076 dump_regset (r
, outf
)
4083 fputs (" (nil)", outf
);
4087 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4089 fprintf (outf
, " %d", i
);
4090 if (i
< FIRST_PSEUDO_REGISTER
)
4091 fprintf (outf
, " [%s]",
4096 /* Print a human-reaable representation of R on the standard error
4097 stream. This function is designed to be used from within the
4104 dump_regset (r
, stderr
);
4105 putc ('\n', stderr
);
4108 /* Dump the rtl into the current debugging dump file, then abort. */
4111 print_rtl_and_abort_fcn (file
, line
, function
)
4114 const char *function
;
4118 print_rtl_with_bb (rtl_dump_file
, get_insns ());
4119 fclose (rtl_dump_file
);
4122 fancy_abort (file
, line
, function
);
4125 /* Recompute register set/reference counts immediately prior to register
4128 This avoids problems with set/reference counts changing to/from values
4129 which have special meanings to the register allocators.
4131 Additionally, the reference counts are the primary component used by the
4132 register allocators to prioritize pseudos for allocation to hard regs.
4133 More accurate reference counts generally lead to better register allocation.
4135 F is the first insn to be scanned.
4137 LOOP_STEP denotes how much loop_depth should be incremented per
4138 loop nesting level in order to increase the ref count more for
4139 references in a loop.
4141 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4142 possibly other information which is used by the register allocators. */
4145 recompute_reg_usage (f
, loop_step
)
4146 rtx f ATTRIBUTE_UNUSED
;
4147 int loop_step ATTRIBUTE_UNUSED
;
4149 allocate_reg_life_data ();
4150 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4153 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4154 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4155 of the number of registers that died. */
4158 count_or_remove_death_notes (blocks
, kill
)
4164 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
4169 if (blocks
&& ! TEST_BIT (blocks
, i
))
4172 bb
= BASIC_BLOCK (i
);
4174 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4178 rtx
*pprev
= ®_NOTES (insn
);
4183 switch (REG_NOTE_KIND (link
))
4186 if (GET_CODE (XEXP (link
, 0)) == REG
)
4188 rtx reg
= XEXP (link
, 0);
4191 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4194 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4202 rtx next
= XEXP (link
, 1);
4203 free_EXPR_LIST_node (link
);
4204 *pprev
= link
= next
;
4210 pprev
= &XEXP (link
, 1);
4217 if (insn
== bb
->end
)
4224 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4225 if blocks is NULL. */
4228 clear_log_links (blocks
)
4236 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4238 free_INSN_LIST_list (&LOG_LINKS (insn
));
4241 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4243 basic_block bb
= BASIC_BLOCK (i
);
4245 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4246 insn
= NEXT_INSN (insn
))
4248 free_INSN_LIST_list (&LOG_LINKS (insn
));
4252 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4253 correspond to the hard registers, if any, set in that map. This
4254 could be done far more efficiently by having all sorts of special-cases
4255 with moving single words, but probably isn't worth the trouble. */
4258 reg_set_to_hard_reg_set (to
, from
)
4264 EXECUTE_IF_SET_IN_BITMAP
4267 if (i
>= FIRST_PSEUDO_REGISTER
)
4269 SET_HARD_REG_BIT (*to
, i
);