1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
144 the stack pointer does not matter. The value is tested only in
145 functions that have frame pointers.
146 No definition is equivalent to always zero. */
147 #ifndef EXIT_IGNORE_STACK
148 #define EXIT_IGNORE_STACK 0
151 #ifndef HAVE_epilogue
152 #define HAVE_epilogue 0
154 #ifndef HAVE_prologue
155 #define HAVE_prologue 0
157 #ifndef HAVE_sibcall_epilogue
158 #define HAVE_sibcall_epilogue 0
162 #define LOCAL_REGNO(REGNO) 0
164 #ifndef EPILOGUE_USES
165 #define EPILOGUE_USES(REGNO) 0
168 #define EH_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 /* Nonzero if the value of CC0 is live. */
275 /* Flags controling the set of information propagate_block collects. */
279 /* Number of dead insns removed. */
282 /* Maximum length of pbi->mem_set_list before we start dropping
283 new elements on the floor. */
284 #define MAX_MEM_SET_LIST_LEN 100
286 /* Forward declarations */
287 static int verify_wide_reg_1
PARAMS ((rtx
*, void *));
288 static void verify_wide_reg
PARAMS ((int, basic_block
));
289 static void verify_local_live_at_start
PARAMS ((regset
, basic_block
));
290 static void notice_stack_pointer_modification_1
PARAMS ((rtx
, rtx
, void *));
291 static void notice_stack_pointer_modification
PARAMS ((rtx
));
292 static void mark_reg
PARAMS ((rtx
, void *));
293 static void mark_regs_live_at_end
PARAMS ((regset
));
294 static int set_phi_alternative_reg
PARAMS ((rtx
, int, int, void *));
295 static void calculate_global_regs_live
PARAMS ((sbitmap
, sbitmap
, int));
296 static void propagate_block_delete_insn
PARAMS ((rtx
));
297 static rtx propagate_block_delete_libcall
PARAMS ((rtx
, rtx
));
298 static int insn_dead_p
PARAMS ((struct propagate_block_info
*,
300 static int libcall_dead_p
PARAMS ((struct propagate_block_info
*,
302 static void mark_set_regs
PARAMS ((struct propagate_block_info
*,
304 static void mark_set_1
PARAMS ((struct propagate_block_info
*,
305 enum rtx_code
, rtx
, rtx
,
307 static int find_regno_partial
PARAMS ((rtx
*, void *));
309 #ifdef HAVE_conditional_execution
310 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
312 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
313 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
314 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
316 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
317 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
318 static rtx not_reg_cond
PARAMS ((rtx
));
319 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
322 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
323 rtx
, rtx
, rtx
, rtx
, rtx
));
324 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
326 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
328 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
330 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
332 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
334 void dump_flow_info
PARAMS ((FILE *));
335 void debug_flow_info
PARAMS ((void));
336 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
338 static int invalidate_mems_from_autoinc
PARAMS ((rtx
*, void *));
339 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
341 static void clear_log_links
PARAMS ((sbitmap
));
345 check_function_return_warnings ()
347 if (warn_missing_noreturn
348 && !TREE_THIS_VOLATILE (cfun
->decl
)
349 && EXIT_BLOCK_PTR
->pred
== NULL
350 && (lang_missing_noreturn_ok_p
351 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
352 warning ("function might be possible candidate for attribute `noreturn'");
354 /* If we have a path to EXIT, then we do return. */
355 if (TREE_THIS_VOLATILE (cfun
->decl
)
356 && EXIT_BLOCK_PTR
->pred
!= NULL
)
357 warning ("`noreturn' function does return");
359 /* If the clobber_return_insn appears in some basic block, then we
360 do reach the end without returning a value. */
361 else if (warn_return_type
362 && cfun
->x_clobber_return_insn
!= NULL
363 && EXIT_BLOCK_PTR
->pred
!= NULL
)
365 int max_uid
= get_max_uid ();
367 /* If clobber_return_insn was excised by jump1, then renumber_insns
368 can make max_uid smaller than the number still recorded in our rtx.
369 That's fine, since this is a quick way of verifying that the insn
370 is no longer in the chain. */
371 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
375 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
376 if (insn
== cfun
->x_clobber_return_insn
)
378 warning ("control reaches end of non-void function");
385 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
386 note associated with the BLOCK. */
389 first_insn_after_basic_block_note (block
)
394 /* Get the first instruction in the block. */
397 if (insn
== NULL_RTX
)
399 if (GET_CODE (insn
) == CODE_LABEL
)
400 insn
= NEXT_INSN (insn
);
401 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
404 return NEXT_INSN (insn
);
407 /* Perform data flow analysis.
408 F is the first insn of the function; FLAGS is a set of PROP_* flags
409 to be used in accumulating flow info. */
412 life_analysis (f
, file
, flags
)
417 #ifdef ELIMINABLE_REGS
419 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
422 /* Record which registers will be eliminated. We use this in
425 CLEAR_HARD_REG_SET (elim_reg_set
);
427 #ifdef ELIMINABLE_REGS
428 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
429 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
431 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
435 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
437 /* The post-reload life analysis have (on a global basis) the same
438 registers live as was computed by reload itself. elimination
439 Otherwise offsets and such may be incorrect.
441 Reload will make some registers as live even though they do not
444 We don't want to create new auto-incs after reload, since they
445 are unlikely to be useful and can cause problems with shared
447 if (reload_completed
)
448 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
450 /* We want alias analysis information for local dead store elimination. */
451 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
452 init_alias_analysis ();
454 /* Always remove no-op moves. Do this before other processing so
455 that we don't have to keep re-scanning them. */
456 delete_noop_moves (f
);
458 /* Some targets can emit simpler epilogues if they know that sp was
459 not ever modified during the function. After reload, of course,
460 we've already emitted the epilogue so there's no sense searching. */
461 if (! reload_completed
)
462 notice_stack_pointer_modification (f
);
464 /* Allocate and zero out data structures that will record the
465 data from lifetime analysis. */
466 allocate_reg_life_data ();
467 allocate_bb_life_data ();
469 /* Find the set of registers live on function exit. */
470 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
472 /* "Update" life info from zero. It'd be nice to begin the
473 relaxation with just the exit and noreturn blocks, but that set
474 is not immediately handy. */
476 if (flags
& PROP_REG_INFO
)
477 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
478 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
481 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
482 end_alias_analysis ();
485 dump_flow_info (file
);
487 free_basic_block_vars (1);
489 /* Removing dead insns should've made jumptables really dead. */
490 delete_dead_jumptables ();
493 /* A subroutine of verify_wide_reg, called through for_each_rtx.
494 Search for REGNO. If found, return 2 if it is not wider than
498 verify_wide_reg_1 (px
, pregno
)
503 unsigned int regno
= *(int *) pregno
;
505 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
507 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
514 /* A subroutine of verify_local_live_at_start. Search through insns
515 of BB looking for register REGNO. */
518 verify_wide_reg (regno
, bb
)
522 rtx head
= bb
->head
, end
= bb
->end
;
528 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
536 head
= NEXT_INSN (head
);
541 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
542 dump_bb (bb
, rtl_dump_file
);
547 /* A subroutine of update_life_info. Verify that there are no untoward
548 changes in live_at_start during a local update. */
551 verify_local_live_at_start (new_live_at_start
, bb
)
552 regset new_live_at_start
;
555 if (reload_completed
)
557 /* After reload, there are no pseudos, nor subregs of multi-word
558 registers. The regsets should exactly match. */
559 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
563 fprintf (rtl_dump_file
,
564 "live_at_start mismatch in bb %d, aborting\nNew:\n",
566 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
567 fputs ("Old:\n", rtl_dump_file
);
568 dump_bb (bb
, rtl_dump_file
);
577 /* Find the set of changed registers. */
578 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
580 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
582 /* No registers should die. */
583 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
587 fprintf (rtl_dump_file
,
588 "Register %d died unexpectedly.\n", i
);
589 dump_bb (bb
, rtl_dump_file
);
594 /* Verify that the now-live register is wider than word_mode. */
595 verify_wide_reg (i
, bb
);
600 /* Updates life information starting with the basic blocks set in BLOCKS.
601 If BLOCKS is null, consider it to be the universal set.
603 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
604 we are only expecting local modifications to basic blocks. If we find
605 extra registers live at the beginning of a block, then we either killed
606 useful data, or we have a broken split that wants data not provided.
607 If we find registers removed from live_at_start, that means we have
608 a broken peephole that is killing a register it shouldn't.
610 ??? This is not true in one situation -- when a pre-reload splitter
611 generates subregs of a multi-word pseudo, current life analysis will
612 lose the kill. So we _can_ have a pseudo go live. How irritating.
614 Including PROP_REG_INFO does not properly refresh regs_ever_live
615 unless the caller resets it to zero. */
618 update_life_info (blocks
, extent
, prop_flags
)
620 enum update_life_extent extent
;
624 regset_head tmp_head
;
626 int stabilized_prop_flags
= prop_flags
;
629 tmp
= INITIALIZE_REG_SET (tmp_head
);
632 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
633 ? TV_LIFE_UPDATE
: TV_LIFE
);
635 /* Changes to the CFG are only allowed when
636 doing a global update for the entire CFG. */
637 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
638 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
641 /* For a global update, we go through the relaxation process again. */
642 if (extent
!= UPDATE_LIFE_LOCAL
)
648 calculate_global_regs_live (blocks
, blocks
,
649 prop_flags
& (PROP_SCAN_DEAD_CODE
650 | PROP_SCAN_DEAD_STORES
651 | PROP_ALLOW_CFG_CHANGES
));
653 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
654 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
657 /* Removing dead code may allow the CFG to be simplified which
658 in turn may allow for further dead code detection / removal. */
659 FOR_EACH_BB_REVERSE (bb
)
661 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
662 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
663 prop_flags
& (PROP_SCAN_DEAD_CODE
664 | PROP_SCAN_DEAD_STORES
665 | PROP_KILL_DEAD_CODE
));
668 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
669 subsequent propagate_block calls, since removing or acting as
670 removing dead code can affect global register liveness, which
671 is supposed to be finalized for this call after this loop. */
672 stabilized_prop_flags
673 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
674 | PROP_KILL_DEAD_CODE
);
679 /* We repeat regardless of what cleanup_cfg says. If there were
680 instructions deleted above, that might have been only a
681 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
682 Further improvement may be possible. */
683 cleanup_cfg (CLEANUP_EXPENSIVE
);
686 /* If asked, remove notes from the blocks we'll update. */
687 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
688 count_or_remove_death_notes (blocks
, 1);
691 /* Clear log links in case we are asked to (re)compute them. */
692 if (prop_flags
& PROP_LOG_LINKS
)
693 clear_log_links (blocks
);
697 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
699 bb
= BASIC_BLOCK (i
);
701 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
702 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
704 if (extent
== UPDATE_LIFE_LOCAL
)
705 verify_local_live_at_start (tmp
, bb
);
710 FOR_EACH_BB_REVERSE (bb
)
712 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
714 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
716 if (extent
== UPDATE_LIFE_LOCAL
)
717 verify_local_live_at_start (tmp
, bb
);
723 if (prop_flags
& PROP_REG_INFO
)
725 /* The only pseudos that are live at the beginning of the function
726 are those that were not set anywhere in the function. local-alloc
727 doesn't know how to handle these correctly, so mark them as not
728 local to any one basic block. */
729 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
730 FIRST_PSEUDO_REGISTER
, i
,
731 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
733 /* We have a problem with any pseudoreg that lives across the setjmp.
734 ANSI says that if a user variable does not change in value between
735 the setjmp and the longjmp, then the longjmp preserves it. This
736 includes longjmp from a place where the pseudo appears dead.
737 (In principle, the value still exists if it is in scope.)
738 If the pseudo goes in a hard reg, some other value may occupy
739 that hard reg where this pseudo is dead, thus clobbering the pseudo.
740 Conclusion: such a pseudo must not go in a hard reg. */
741 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
742 FIRST_PSEUDO_REGISTER
, i
,
744 if (regno_reg_rtx
[i
] != 0)
746 REG_LIVE_LENGTH (i
) = -1;
747 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
751 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
752 ? TV_LIFE_UPDATE
: TV_LIFE
);
753 if (ndead
&& rtl_dump_file
)
754 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
758 /* Update life information in all blocks where BB_DIRTY is set. */
761 update_life_info_in_dirty_blocks (extent
, prop_flags
)
762 enum update_life_extent extent
;
765 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
770 sbitmap_zero (update_life_blocks
);
773 if (extent
== UPDATE_LIFE_LOCAL
)
775 if (bb
->flags
& BB_DIRTY
)
777 SET_BIT (update_life_blocks
, bb
->index
);
783 /* ??? Bootstrap with -march=pentium4 fails to terminate
784 with only a partial life update. */
785 SET_BIT (update_life_blocks
, bb
->index
);
786 if (bb
->flags
& BB_DIRTY
)
792 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
794 sbitmap_free (update_life_blocks
);
798 /* Free the variables allocated by find_basic_blocks.
800 KEEP_HEAD_END_P is nonzero if basic_block_info is not to be freed. */
803 free_basic_block_vars (keep_head_end_p
)
806 if (! keep_head_end_p
)
808 if (basic_block_info
)
811 VARRAY_FREE (basic_block_info
);
814 last_basic_block
= 0;
816 ENTRY_BLOCK_PTR
->aux
= NULL
;
817 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
818 EXIT_BLOCK_PTR
->aux
= NULL
;
819 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
823 /* Delete any insns that copy a register to itself. */
826 delete_noop_moves (f
)
827 rtx f ATTRIBUTE_UNUSED
;
835 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
837 next
= NEXT_INSN (insn
);
838 if (INSN_P (insn
) && noop_move_p (insn
))
842 /* If we're about to remove the first insn of a libcall
843 then move the libcall note to the next real insn and
844 update the retval note. */
845 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
846 && XEXP (note
, 0) != insn
)
848 rtx new_libcall_insn
= next_real_insn (insn
);
849 rtx retval_note
= find_reg_note (XEXP (note
, 0),
850 REG_RETVAL
, NULL_RTX
);
851 REG_NOTES (new_libcall_insn
)
852 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
853 REG_NOTES (new_libcall_insn
));
854 XEXP (retval_note
, 0) = new_libcall_insn
;
857 delete_insn_and_edges (insn
);
862 if (nnoops
&& rtl_dump_file
)
863 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
867 /* Delete any jump tables never referenced. We can't delete them at the
868 time of removing tablejump insn as they are referenced by the preceding
869 insns computing the destination, so we delay deleting and garbagecollect
870 them once life information is computed. */
872 delete_dead_jumptables ()
875 for (insn
= get_insns (); insn
; insn
= next
)
877 next
= NEXT_INSN (insn
);
878 if (GET_CODE (insn
) == CODE_LABEL
879 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
880 && GET_CODE (next
) == JUMP_INSN
881 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
882 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
885 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
886 delete_insn (NEXT_INSN (insn
));
888 next
= NEXT_INSN (next
);
893 /* Determine if the stack pointer is constant over the life of the function.
894 Only useful before prologues have been emitted. */
897 notice_stack_pointer_modification_1 (x
, pat
, data
)
899 rtx pat ATTRIBUTE_UNUSED
;
900 void *data ATTRIBUTE_UNUSED
;
902 if (x
== stack_pointer_rtx
903 /* The stack pointer is only modified indirectly as the result
904 of a push until later in flow. See the comments in rtl.texi
905 regarding Embedded Side-Effects on Addresses. */
906 || (GET_CODE (x
) == MEM
907 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
908 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
909 current_function_sp_is_unchanging
= 0;
913 notice_stack_pointer_modification (f
)
918 /* Assume that the stack pointer is unchanging if alloca hasn't
920 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
921 if (! current_function_sp_is_unchanging
)
924 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
928 /* Check if insn modifies the stack pointer. */
929 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
931 if (! current_function_sp_is_unchanging
)
937 /* Mark a register in SET. Hard registers in large modes get all
938 of their component registers set as well. */
945 regset set
= (regset
) xset
;
946 int regno
= REGNO (reg
);
948 if (GET_MODE (reg
) == BLKmode
)
951 SET_REGNO_REG_SET (set
, regno
);
952 if (regno
< FIRST_PSEUDO_REGISTER
)
954 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
956 SET_REGNO_REG_SET (set
, regno
+ n
);
960 /* Mark those regs which are needed at the end of the function as live
961 at the end of the last basic block. */
964 mark_regs_live_at_end (set
)
969 /* If exiting needs the right stack value, consider the stack pointer
970 live at the end of the function. */
971 if ((HAVE_epilogue
&& reload_completed
)
972 || ! EXIT_IGNORE_STACK
973 || (! FRAME_POINTER_REQUIRED
974 && ! current_function_calls_alloca
975 && flag_omit_frame_pointer
)
976 || current_function_sp_is_unchanging
)
978 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
981 /* Mark the frame pointer if needed at the end of the function. If
982 we end up eliminating it, it will be removed from the live list
983 of each basic block by reload. */
985 if (! reload_completed
|| frame_pointer_needed
)
987 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
988 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
989 /* If they are different, also mark the hard frame pointer as live. */
990 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
991 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
995 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
996 /* Many architectures have a GP register even without flag_pic.
997 Assume the pic register is not in use, or will be handled by
998 other means, if it is not fixed. */
999 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1000 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1001 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1004 /* Mark all global registers, and all registers used by the epilogue
1005 as being live at the end of the function since they may be
1006 referenced by our caller. */
1007 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1008 if (global_regs
[i
] || EPILOGUE_USES (i
))
1009 SET_REGNO_REG_SET (set
, i
);
1011 if (HAVE_epilogue
&& reload_completed
)
1013 /* Mark all call-saved registers that we actually used. */
1014 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1015 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1016 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1017 SET_REGNO_REG_SET (set
, i
);
1020 #ifdef EH_RETURN_DATA_REGNO
1021 /* Mark the registers that will contain data for the handler. */
1022 if (reload_completed
&& current_function_calls_eh_return
)
1025 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1026 if (regno
== INVALID_REGNUM
)
1028 SET_REGNO_REG_SET (set
, regno
);
1031 #ifdef EH_RETURN_STACKADJ_RTX
1032 if ((! HAVE_epilogue
|| ! reload_completed
)
1033 && current_function_calls_eh_return
)
1035 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1036 if (tmp
&& REG_P (tmp
))
1037 mark_reg (tmp
, set
);
1040 #ifdef EH_RETURN_HANDLER_RTX
1041 if ((! HAVE_epilogue
|| ! reload_completed
)
1042 && current_function_calls_eh_return
)
1044 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1045 if (tmp
&& REG_P (tmp
))
1046 mark_reg (tmp
, set
);
1050 /* Mark function return value. */
1051 diddle_return_value (mark_reg
, set
);
1054 /* Callback function for for_each_successor_phi. DATA is a regset.
1055 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1056 INSN, in the regset. */
1059 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1060 rtx insn ATTRIBUTE_UNUSED
;
1061 int dest_regno ATTRIBUTE_UNUSED
;
1065 regset live
= (regset
) data
;
1066 SET_REGNO_REG_SET (live
, src_regno
);
1070 /* Propagate global life info around the graph of basic blocks. Begin
1071 considering blocks with their corresponding bit set in BLOCKS_IN.
1072 If BLOCKS_IN is null, consider it the universal set.
1074 BLOCKS_OUT is set for every block that was changed. */
1077 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1078 sbitmap blocks_in
, blocks_out
;
1081 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1082 regset tmp
, new_live_at_end
, invalidated_by_call
;
1083 regset_head tmp_head
, invalidated_by_call_head
;
1084 regset_head new_live_at_end_head
;
1087 /* Some passes used to forget clear aux field of basic block causing
1088 sick behavior here. */
1089 #ifdef ENABLE_CHECKING
1090 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1095 tmp
= INITIALIZE_REG_SET (tmp_head
);
1096 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1097 invalidated_by_call
= INITIALIZE_REG_SET (invalidated_by_call_head
);
1099 /* Inconveniently, this is only readily available in hard reg set form. */
1100 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1101 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1102 SET_REGNO_REG_SET (invalidated_by_call
, i
);
1104 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1105 because the `head == tail' style test for an empty queue doesn't
1106 work with a full queue. */
1107 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1109 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1111 /* Queue the blocks set in the initial mask. Do this in reverse block
1112 number order so that we are more likely for the first round to do
1113 useful work. We use AUX non-null to flag that the block is queued. */
1117 if (TEST_BIT (blocks_in
, bb
->index
))
1132 /* We clean aux when we remove the initially-enqueued bbs, but we
1133 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1135 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1138 sbitmap_zero (blocks_out
);
1140 /* We work through the queue until there are no more blocks. What
1141 is live at the end of this block is precisely the union of what
1142 is live at the beginning of all its successors. So, we set its
1143 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1144 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1145 this block by walking through the instructions in this block in
1146 reverse order and updating as we go. If that changed
1147 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1148 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1150 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1151 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1152 must either be live at the end of the block, or used within the
1153 block. In the latter case, it will certainly never disappear
1154 from GLOBAL_LIVE_AT_START. In the former case, the register
1155 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1156 for one of the successor blocks. By induction, that cannot
1158 while (qhead
!= qtail
)
1160 int rescan
, changed
;
1169 /* Begin by propagating live_at_start from the successor blocks. */
1170 CLEAR_REG_SET (new_live_at_end
);
1173 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1175 basic_block sb
= e
->dest
;
1177 /* Call-clobbered registers die across exception and
1179 /* ??? Abnormal call edges ignored for the moment, as this gets
1180 confused by sibling call edges, which crashes reg-stack. */
1181 if (e
->flags
& EDGE_EH
)
1183 bitmap_operation (tmp
, sb
->global_live_at_start
,
1184 invalidated_by_call
, BITMAP_AND_COMPL
);
1185 IOR_REG_SET (new_live_at_end
, tmp
);
1188 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1190 /* If a target saves one register in another (instead of on
1191 the stack) the save register will need to be live for EH. */
1192 if (e
->flags
& EDGE_EH
)
1193 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1195 SET_REGNO_REG_SET (new_live_at_end
, i
);
1199 /* This might be a noreturn function that throws. And
1200 even if it isn't, getting the unwind info right helps
1202 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1204 SET_REGNO_REG_SET (new_live_at_end
, i
);
1207 /* The all-important stack pointer must always be live. */
1208 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1210 /* Before reload, there are a few registers that must be forced
1211 live everywhere -- which might not already be the case for
1212 blocks within infinite loops. */
1213 if (! reload_completed
)
1215 /* Any reference to any pseudo before reload is a potential
1216 reference of the frame pointer. */
1217 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1219 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1220 /* Pseudos with argument area equivalences may require
1221 reloading via the argument pointer. */
1222 if (fixed_regs
[ARG_POINTER_REGNUM
])
1223 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1226 /* Any constant, or pseudo with constant equivalences, may
1227 require reloading from memory using the pic register. */
1228 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1229 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1230 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1233 /* Regs used in phi nodes are not included in
1234 global_live_at_start, since they are live only along a
1235 particular edge. Set those regs that are live because of a
1236 phi node alternative corresponding to this particular block. */
1238 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1241 if (bb
== ENTRY_BLOCK_PTR
)
1243 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1247 /* On our first pass through this block, we'll go ahead and continue.
1248 Recognize first pass by local_set NULL. On subsequent passes, we
1249 get to skip out early if live_at_end wouldn't have changed. */
1251 if (bb
->local_set
== NULL
)
1253 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1254 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1259 /* If any bits were removed from live_at_end, we'll have to
1260 rescan the block. This wouldn't be necessary if we had
1261 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1262 local_live is really dependent on live_at_end. */
1263 CLEAR_REG_SET (tmp
);
1264 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1265 new_live_at_end
, BITMAP_AND_COMPL
);
1269 /* If any of the registers in the new live_at_end set are
1270 conditionally set in this basic block, we must rescan.
1271 This is because conditional lifetimes at the end of the
1272 block do not just take the live_at_end set into account,
1273 but also the liveness at the start of each successor
1274 block. We can miss changes in those sets if we only
1275 compare the new live_at_end against the previous one. */
1276 CLEAR_REG_SET (tmp
);
1277 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1278 bb
->cond_local_set
, BITMAP_AND
);
1283 /* Find the set of changed bits. Take this opportunity
1284 to notice that this set is empty and early out. */
1285 CLEAR_REG_SET (tmp
);
1286 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1287 new_live_at_end
, BITMAP_XOR
);
1291 /* If any of the changed bits overlap with local_set,
1292 we'll have to rescan the block. Detect overlap by
1293 the AND with ~local_set turning off bits. */
1294 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1299 /* Let our caller know that BB changed enough to require its
1300 death notes updated. */
1302 SET_BIT (blocks_out
, bb
->index
);
1306 /* Add to live_at_start the set of all registers in
1307 new_live_at_end that aren't in the old live_at_end. */
1309 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1311 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1313 changed
= bitmap_operation (bb
->global_live_at_start
,
1314 bb
->global_live_at_start
,
1321 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1323 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1324 into live_at_start. */
1325 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1326 bb
->cond_local_set
, flags
);
1328 /* If live_at start didn't change, no need to go farther. */
1329 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1332 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1335 /* Queue all predecessors of BB so that we may re-examine
1336 their live_at_end. */
1337 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1339 basic_block pb
= e
->src
;
1340 if (pb
->aux
== NULL
)
1351 FREE_REG_SET (new_live_at_end
);
1352 FREE_REG_SET (invalidated_by_call
);
1356 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1358 basic_block bb
= BASIC_BLOCK (i
);
1359 FREE_REG_SET (bb
->local_set
);
1360 FREE_REG_SET (bb
->cond_local_set
);
1367 FREE_REG_SET (bb
->local_set
);
1368 FREE_REG_SET (bb
->cond_local_set
);
1376 /* This structure is used to pass parameters to an from the
1377 the function find_regno_partial(). It is used to pass in the
1378 register number we are looking, as well as to return any rtx
1382 unsigned regno_to_find
;
1384 } find_regno_partial_param
;
1387 /* Find the rtx for the reg numbers specified in 'data' if it is
1388 part of an expression which only uses part of the register. Return
1389 it in the structure passed in. */
1391 find_regno_partial (ptr
, data
)
1395 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1396 unsigned reg
= param
->regno_to_find
;
1397 param
->retval
= NULL_RTX
;
1399 if (*ptr
== NULL_RTX
)
1402 switch (GET_CODE (*ptr
))
1406 case STRICT_LOW_PART
:
1407 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1409 param
->retval
= XEXP (*ptr
, 0);
1415 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1416 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1418 param
->retval
= SUBREG_REG (*ptr
);
1430 /* Process all immediate successors of the entry block looking for pseudo
1431 registers which are live on entry. Find all of those whose first
1432 instance is a partial register reference of some kind, and initialize
1433 them to 0 after the entry block. This will prevent bit sets within
1434 registers whose value is unknown, and may contain some kind of sticky
1435 bits we don't want. */
1438 initialize_uninitialized_subregs ()
1442 int reg
, did_something
= 0;
1443 find_regno_partial_param param
;
1445 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1447 basic_block bb
= e
->dest
;
1448 regset map
= bb
->global_live_at_start
;
1449 EXECUTE_IF_SET_IN_REG_SET (map
,
1450 FIRST_PSEUDO_REGISTER
, reg
,
1452 int uid
= REGNO_FIRST_UID (reg
);
1455 /* Find an insn which mentions the register we are looking for.
1456 Its preferable to have an instance of the register's rtl since
1457 there may be various flags set which we need to duplicate.
1458 If we can't find it, its probably an automatic whose initial
1459 value doesn't matter, or hopefully something we don't care about. */
1460 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1464 /* Found the insn, now get the REG rtx, if we can. */
1465 param
.regno_to_find
= reg
;
1466 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1467 if (param
.retval
!= NULL_RTX
)
1469 insn
= gen_move_insn (param
.retval
,
1470 CONST0_RTX (GET_MODE (param
.retval
)));
1471 insert_insn_on_edge (insn
, e
);
1479 commit_edge_insertions ();
1480 return did_something
;
1484 /* Subroutines of life analysis. */
1486 /* Allocate the permanent data structures that represent the results
1487 of life analysis. Not static since used also for stupid life analysis. */
1490 allocate_bb_life_data ()
1494 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1496 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1497 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1500 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1504 allocate_reg_life_data ()
1508 max_regno
= max_reg_num ();
1510 /* Recalculate the register space, in case it has grown. Old style
1511 vector oriented regsets would set regset_{size,bytes} here also. */
1512 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1514 /* Reset all the data we'll collect in propagate_block and its
1516 for (i
= 0; i
< max_regno
; i
++)
1520 REG_N_DEATHS (i
) = 0;
1521 REG_N_CALLS_CROSSED (i
) = 0;
1522 REG_LIVE_LENGTH (i
) = 0;
1523 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1527 /* Delete dead instructions for propagate_block. */
1530 propagate_block_delete_insn (insn
)
1533 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1535 /* If the insn referred to a label, and that label was attached to
1536 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1537 pretty much mandatory to delete it, because the ADDR_VEC may be
1538 referencing labels that no longer exist.
1540 INSN may reference a deleted label, particularly when a jump
1541 table has been optimized into a direct jump. There's no
1542 real good way to fix up the reference to the deleted label
1543 when the label is deleted, so we just allow it here. */
1545 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1547 rtx label
= XEXP (inote
, 0);
1550 /* The label may be forced if it has been put in the constant
1551 pool. If that is the only use we must discard the table
1552 jump following it, but not the label itself. */
1553 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1554 && (next
= next_nonnote_insn (label
)) != NULL
1555 && GET_CODE (next
) == JUMP_INSN
1556 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1557 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1559 rtx pat
= PATTERN (next
);
1560 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1561 int len
= XVECLEN (pat
, diff_vec_p
);
1564 for (i
= 0; i
< len
; i
++)
1565 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1567 delete_insn_and_edges (next
);
1572 delete_insn_and_edges (insn
);
1576 /* Delete dead libcalls for propagate_block. Return the insn
1577 before the libcall. */
1580 propagate_block_delete_libcall ( insn
, note
)
1583 rtx first
= XEXP (note
, 0);
1584 rtx before
= PREV_INSN (first
);
1586 delete_insn_chain_and_edges (first
, insn
);
1591 /* Update the life-status of regs for one insn. Return the previous insn. */
1594 propagate_one_insn (pbi
, insn
)
1595 struct propagate_block_info
*pbi
;
1598 rtx prev
= PREV_INSN (insn
);
1599 int flags
= pbi
->flags
;
1600 int insn_is_dead
= 0;
1601 int libcall_is_dead
= 0;
1605 if (! INSN_P (insn
))
1608 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1609 if (flags
& PROP_SCAN_DEAD_CODE
)
1611 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1612 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1613 && libcall_dead_p (pbi
, note
, insn
));
1616 /* If an instruction consists of just dead store(s) on final pass,
1618 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1620 /* If we're trying to delete a prologue or epilogue instruction
1621 that isn't flagged as possibly being dead, something is wrong.
1622 But if we are keeping the stack pointer depressed, we might well
1623 be deleting insns that are used to compute the amount to update
1624 it by, so they are fine. */
1625 if (reload_completed
1626 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1627 && (TYPE_RETURNS_STACK_DEPRESSED
1628 (TREE_TYPE (current_function_decl
))))
1629 && (((HAVE_epilogue
|| HAVE_prologue
)
1630 && prologue_epilogue_contains (insn
))
1631 || (HAVE_sibcall_epilogue
1632 && sibcall_epilogue_contains (insn
)))
1633 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1634 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1636 /* Record sets. Do this even for dead instructions, since they
1637 would have killed the values if they hadn't been deleted. */
1638 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1640 /* CC0 is now known to be dead. Either this insn used it,
1641 in which case it doesn't anymore, or clobbered it,
1642 so the next insn can't use it. */
1645 if (libcall_is_dead
)
1646 prev
= propagate_block_delete_libcall ( insn
, note
);
1650 /* If INSN contains a RETVAL note and is dead, but the libcall
1651 as a whole is not dead, then we want to remove INSN, but
1652 not the whole libcall sequence.
1654 However, we need to also remove the dangling REG_LIBCALL
1655 note so that we do not have mis-matched LIBCALL/RETVAL
1656 notes. In theory we could find a new location for the
1657 REG_RETVAL note, but it hardly seems worth the effort.
1659 NOTE at this point will be the RETVAL note if it exists. */
1665 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1666 remove_note (XEXP (note
, 0), libcall_note
);
1669 /* Similarly if INSN contains a LIBCALL note, remove the
1670 dnagling REG_RETVAL note. */
1671 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
1677 = find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
1678 remove_note (XEXP (note
, 0), retval_note
);
1681 /* Now delete INSN. */
1682 propagate_block_delete_insn (insn
);
1688 /* See if this is an increment or decrement that can be merged into
1689 a following memory address. */
1692 rtx x
= single_set (insn
);
1694 /* Does this instruction increment or decrement a register? */
1695 if ((flags
& PROP_AUTOINC
)
1697 && GET_CODE (SET_DEST (x
)) == REG
1698 && (GET_CODE (SET_SRC (x
)) == PLUS
1699 || GET_CODE (SET_SRC (x
)) == MINUS
)
1700 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1701 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1702 /* Ok, look for a following memory ref we can combine with.
1703 If one is found, change the memory ref to a PRE_INC
1704 or PRE_DEC, cancel this insn, and return 1.
1705 Return 0 if nothing has been done. */
1706 && try_pre_increment_1 (pbi
, insn
))
1709 #endif /* AUTO_INC_DEC */
1711 CLEAR_REG_SET (pbi
->new_set
);
1713 /* If this is not the final pass, and this insn is copying the value of
1714 a library call and it's dead, don't scan the insns that perform the
1715 library call, so that the call's arguments are not marked live. */
1716 if (libcall_is_dead
)
1718 /* Record the death of the dest reg. */
1719 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1721 insn
= XEXP (note
, 0);
1722 return PREV_INSN (insn
);
1724 else if (GET_CODE (PATTERN (insn
)) == SET
1725 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1726 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1727 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1728 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1729 /* We have an insn to pop a constant amount off the stack.
1730 (Such insns use PLUS regardless of the direction of the stack,
1731 and any insn to adjust the stack by a constant is always a pop.)
1732 These insns, if not dead stores, have no effect on life, though
1733 they do have an effect on the memory stores we are tracking. */
1734 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1738 /* Any regs live at the time of a call instruction must not go
1739 in a register clobbered by calls. Find all regs now live and
1740 record this for them. */
1742 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1743 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1744 { REG_N_CALLS_CROSSED (i
)++; });
1746 /* Record sets. Do this even for dead instructions, since they
1747 would have killed the values if they hadn't been deleted. */
1748 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1750 if (GET_CODE (insn
) == CALL_INSN
)
1756 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1757 cond
= COND_EXEC_TEST (PATTERN (insn
));
1759 /* Non-constant calls clobber memory, constant calls do not
1760 clobber memory, though they may clobber outgoing arguments
1762 if (! CONST_OR_PURE_CALL_P (insn
))
1764 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1765 pbi
->mem_set_list_len
= 0;
1768 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1770 /* There may be extra registers to be clobbered. */
1771 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1773 note
= XEXP (note
, 1))
1774 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1775 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1776 cond
, insn
, pbi
->flags
);
1778 /* Calls change all call-used and global registers. */
1779 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1780 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1782 /* We do not want REG_UNUSED notes for these registers. */
1783 mark_set_1 (pbi
, CLOBBER
, regno_reg_rtx
[i
], cond
, insn
,
1784 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1788 /* If an insn doesn't use CC0, it becomes dead since we assume
1789 that every insn clobbers it. So show it dead here;
1790 mark_used_regs will set it live if it is referenced. */
1795 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1796 if ((flags
& PROP_EQUAL_NOTES
)
1797 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1798 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1799 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1801 /* Sometimes we may have inserted something before INSN (such as a move)
1802 when we make an auto-inc. So ensure we will scan those insns. */
1804 prev
= PREV_INSN (insn
);
1807 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1813 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1814 cond
= COND_EXEC_TEST (PATTERN (insn
));
1816 /* Calls use their arguments. */
1817 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1819 note
= XEXP (note
, 1))
1820 if (GET_CODE (XEXP (note
, 0)) == USE
)
1821 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1824 /* The stack ptr is used (honorarily) by a CALL insn. */
1825 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1827 /* Calls may also reference any of the global registers,
1828 so they are made live. */
1829 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1831 mark_used_reg (pbi
, regno_reg_rtx
[i
], cond
, insn
);
1835 /* On final pass, update counts of how many insns in which each reg
1837 if (flags
& PROP_REG_INFO
)
1838 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1839 { REG_LIVE_LENGTH (i
)++; });
1844 /* Initialize a propagate_block_info struct for public consumption.
1845 Note that the structure itself is opaque to this file, but that
1846 the user can use the regsets provided here. */
1848 struct propagate_block_info
*
1849 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1851 regset live
, local_set
, cond_local_set
;
1854 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1857 pbi
->reg_live
= live
;
1858 pbi
->mem_set_list
= NULL_RTX
;
1859 pbi
->mem_set_list_len
= 0;
1860 pbi
->local_set
= local_set
;
1861 pbi
->cond_local_set
= cond_local_set
;
1865 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1866 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1868 pbi
->reg_next_use
= NULL
;
1870 pbi
->new_set
= BITMAP_XMALLOC ();
1872 #ifdef HAVE_conditional_execution
1873 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1874 free_reg_cond_life_info
);
1875 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1877 /* If this block ends in a conditional branch, for each register live
1878 from one side of the branch and not the other, record the register
1879 as conditionally dead. */
1880 if (GET_CODE (bb
->end
) == JUMP_INSN
1881 && any_condjump_p (bb
->end
))
1883 regset_head diff_head
;
1884 regset diff
= INITIALIZE_REG_SET (diff_head
);
1885 basic_block bb_true
, bb_false
;
1886 rtx cond_true
, cond_false
, set_src
;
1889 /* Identify the successor blocks. */
1890 bb_true
= bb
->succ
->dest
;
1891 if (bb
->succ
->succ_next
!= NULL
)
1893 bb_false
= bb
->succ
->succ_next
->dest
;
1895 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1897 basic_block t
= bb_false
;
1901 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1906 /* This can happen with a conditional jump to the next insn. */
1907 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1910 /* Simplest way to do nothing. */
1914 /* Extract the condition from the branch. */
1915 set_src
= SET_SRC (pc_set (bb
->end
));
1916 cond_true
= XEXP (set_src
, 0);
1917 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1918 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1919 XEXP (cond_true
, 1));
1920 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1923 cond_false
= cond_true
;
1927 /* Compute which register lead different lives in the successors. */
1928 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1929 bb_false
->global_live_at_start
, BITMAP_XOR
))
1931 rtx reg
= XEXP (cond_true
, 0);
1933 if (GET_CODE (reg
) == SUBREG
)
1934 reg
= SUBREG_REG (reg
);
1936 if (GET_CODE (reg
) != REG
)
1939 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1941 /* For each such register, mark it conditionally dead. */
1942 EXECUTE_IF_SET_IN_REG_SET
1945 struct reg_cond_life_info
*rcli
;
1948 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1950 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1954 rcli
->condition
= cond
;
1955 rcli
->stores
= const0_rtx
;
1956 rcli
->orig_condition
= cond
;
1958 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1959 (splay_tree_value
) rcli
);
1963 FREE_REG_SET (diff
);
1967 /* If this block has no successors, any stores to the frame that aren't
1968 used later in the block are dead. So make a pass over the block
1969 recording any such that are made and show them dead at the end. We do
1970 a very conservative and simple job here. */
1972 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1973 && (TYPE_RETURNS_STACK_DEPRESSED
1974 (TREE_TYPE (current_function_decl
))))
1975 && (flags
& PROP_SCAN_DEAD_STORES
)
1976 && (bb
->succ
== NULL
1977 || (bb
->succ
->succ_next
== NULL
1978 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1979 && ! current_function_calls_eh_return
)))
1982 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1983 if (GET_CODE (insn
) == INSN
1984 && (set
= single_set (insn
))
1985 && GET_CODE (SET_DEST (set
)) == MEM
)
1987 rtx mem
= SET_DEST (set
);
1988 rtx canon_mem
= canon_rtx (mem
);
1990 /* This optimization is performed by faking a store to the
1991 memory at the end of the block. This doesn't work for
1992 unchanging memories because multiple stores to unchanging
1993 memory is illegal and alias analysis doesn't consider it. */
1994 if (RTX_UNCHANGING_P (canon_mem
))
1997 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1998 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1999 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
2000 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
2001 add_to_mem_set_list (pbi
, canon_mem
);
2008 /* Release a propagate_block_info struct. */
2011 free_propagate_block_info (pbi
)
2012 struct propagate_block_info
*pbi
;
2014 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2016 BITMAP_XFREE (pbi
->new_set
);
2018 #ifdef HAVE_conditional_execution
2019 splay_tree_delete (pbi
->reg_cond_dead
);
2020 BITMAP_XFREE (pbi
->reg_cond_reg
);
2023 if (pbi
->reg_next_use
)
2024 free (pbi
->reg_next_use
);
2029 /* Compute the registers live at the beginning of a basic block BB from
2030 those live at the end.
2032 When called, REG_LIVE contains those live at the end. On return, it
2033 contains those live at the beginning.
2035 LOCAL_SET, if non-null, will be set with all registers killed
2036 unconditionally by this basic block.
2037 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2038 killed conditionally by this basic block. If there is any unconditional
2039 set of a register, then the corresponding bit will be set in LOCAL_SET
2040 and cleared in COND_LOCAL_SET.
2041 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2042 case, the resulting set will be equal to the union of the two sets that
2043 would otherwise be computed.
2045 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2048 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2052 regset cond_local_set
;
2055 struct propagate_block_info
*pbi
;
2059 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2061 if (flags
& PROP_REG_INFO
)
2065 /* Process the regs live at the end of the block.
2066 Mark them as not local to any one basic block. */
2067 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2068 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2071 /* Scan the block an insn at a time from end to beginning. */
2074 for (insn
= bb
->end
;; insn
= prev
)
2076 /* If this is a call to `setjmp' et al, warn if any
2077 non-volatile datum is live. */
2078 if ((flags
& PROP_REG_INFO
)
2079 && GET_CODE (insn
) == CALL_INSN
2080 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2081 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2083 prev
= propagate_one_insn (pbi
, insn
);
2084 changed
|= NEXT_INSN (prev
) != insn
;
2086 if (insn
== bb
->head
)
2090 free_propagate_block_info (pbi
);
2095 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2096 (SET expressions whose destinations are registers dead after the insn).
2097 NEEDED is the regset that says which regs are alive after the insn.
2099 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2101 If X is the entire body of an insn, NOTES contains the reg notes
2102 pertaining to the insn. */
2105 insn_dead_p (pbi
, x
, call_ok
, notes
)
2106 struct propagate_block_info
*pbi
;
2109 rtx notes ATTRIBUTE_UNUSED
;
2111 enum rtx_code code
= GET_CODE (x
);
2113 /* Don't eliminate insns that may trap. */
2114 if (flag_non_call_exceptions
&& may_trap_p (x
))
2118 /* As flow is invoked after combine, we must take existing AUTO_INC
2119 expressions into account. */
2120 for (; notes
; notes
= XEXP (notes
, 1))
2122 if (REG_NOTE_KIND (notes
) == REG_INC
)
2124 int regno
= REGNO (XEXP (notes
, 0));
2126 /* Don't delete insns to set global regs. */
2127 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2128 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2134 /* If setting something that's a reg or part of one,
2135 see if that register's altered value will be live. */
2139 rtx r
= SET_DEST (x
);
2142 if (GET_CODE (r
) == CC0
)
2143 return ! pbi
->cc0_live
;
2146 /* A SET that is a subroutine call cannot be dead. */
2147 if (GET_CODE (SET_SRC (x
)) == CALL
)
2153 /* Don't eliminate loads from volatile memory or volatile asms. */
2154 else if (volatile_refs_p (SET_SRC (x
)))
2157 if (GET_CODE (r
) == MEM
)
2161 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2164 canon_r
= canon_rtx (r
);
2166 /* Walk the set of memory locations we are currently tracking
2167 and see if one is an identical match to this memory location.
2168 If so, this memory write is dead (remember, we're walking
2169 backwards from the end of the block to the start). Since
2170 rtx_equal_p does not check the alias set or flags, we also
2171 must have the potential for them to conflict (anti_dependence). */
2172 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2173 if (anti_dependence (r
, XEXP (temp
, 0)))
2175 rtx mem
= XEXP (temp
, 0);
2177 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2178 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2179 <= GET_MODE_SIZE (GET_MODE (mem
))))
2183 /* Check if memory reference matches an auto increment. Only
2184 post increment/decrement or modify are valid. */
2185 if (GET_MODE (mem
) == GET_MODE (r
)
2186 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2187 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2188 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2189 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2190 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2197 while (GET_CODE (r
) == SUBREG
2198 || GET_CODE (r
) == STRICT_LOW_PART
2199 || GET_CODE (r
) == ZERO_EXTRACT
)
2202 if (GET_CODE (r
) == REG
)
2204 int regno
= REGNO (r
);
2207 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2210 /* If this is a hard register, verify that subsequent
2211 words are not needed. */
2212 if (regno
< FIRST_PSEUDO_REGISTER
)
2214 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2217 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2221 /* Don't delete insns to set global regs. */
2222 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2225 /* Make sure insns to set the stack pointer aren't deleted. */
2226 if (regno
== STACK_POINTER_REGNUM
)
2229 /* ??? These bits might be redundant with the force live bits
2230 in calculate_global_regs_live. We would delete from
2231 sequential sets; whether this actually affects real code
2232 for anything but the stack pointer I don't know. */
2233 /* Make sure insns to set the frame pointer aren't deleted. */
2234 if (regno
== FRAME_POINTER_REGNUM
2235 && (! reload_completed
|| frame_pointer_needed
))
2237 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2238 if (regno
== HARD_FRAME_POINTER_REGNUM
2239 && (! reload_completed
|| frame_pointer_needed
))
2243 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2244 /* Make sure insns to set arg pointer are never deleted
2245 (if the arg pointer isn't fixed, there will be a USE
2246 for it, so we can treat it normally). */
2247 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2251 /* Otherwise, the set is dead. */
2257 /* If performing several activities, insn is dead if each activity
2258 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2259 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2261 else if (code
== PARALLEL
)
2263 int i
= XVECLEN (x
, 0);
2265 for (i
--; i
>= 0; i
--)
2266 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2267 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2268 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2274 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2275 is not necessarily true for hard registers. */
2276 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2277 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2278 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2281 /* We do not check other CLOBBER or USE here. An insn consisting of just
2282 a CLOBBER or just a USE should not be deleted. */
2286 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2287 return 1 if the entire library call is dead.
2288 This is true if INSN copies a register (hard or pseudo)
2289 and if the hard return reg of the call insn is dead.
2290 (The caller should have tested the destination of the SET inside
2291 INSN already for death.)
2293 If this insn doesn't just copy a register, then we don't
2294 have an ordinary libcall. In that case, cse could not have
2295 managed to substitute the source for the dest later on,
2296 so we can assume the libcall is dead.
2298 PBI is the block info giving pseudoregs live before this insn.
2299 NOTE is the REG_RETVAL note of the insn. */
2302 libcall_dead_p (pbi
, note
, insn
)
2303 struct propagate_block_info
*pbi
;
2307 rtx x
= single_set (insn
);
2311 rtx r
= SET_SRC (x
);
2313 if (GET_CODE (r
) == REG
)
2315 rtx call
= XEXP (note
, 0);
2319 /* Find the call insn. */
2320 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2321 call
= NEXT_INSN (call
);
2323 /* If there is none, do nothing special,
2324 since ordinary death handling can understand these insns. */
2328 /* See if the hard reg holding the value is dead.
2329 If this is a PARALLEL, find the call within it. */
2330 call_pat
= PATTERN (call
);
2331 if (GET_CODE (call_pat
) == PARALLEL
)
2333 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2334 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2335 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2338 /* This may be a library call that is returning a value
2339 via invisible pointer. Do nothing special, since
2340 ordinary death handling can understand these insns. */
2344 call_pat
= XVECEXP (call_pat
, 0, i
);
2347 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2353 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2354 live at function entry. Don't count global register variables, variables
2355 in registers that can be used for function arg passing, or variables in
2356 fixed hard registers. */
2359 regno_uninitialized (regno
)
2362 if (n_basic_blocks
== 0
2363 || (regno
< FIRST_PSEUDO_REGISTER
2364 && (global_regs
[regno
]
2365 || fixed_regs
[regno
]
2366 || FUNCTION_ARG_REGNO_P (regno
))))
2369 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2372 /* 1 if register REGNO was alive at a place where `setjmp' was called
2373 and was set more than once or is an argument.
2374 Such regs may be clobbered by `longjmp'. */
2377 regno_clobbered_at_setjmp (regno
)
2380 if (n_basic_blocks
== 0)
2383 return ((REG_N_SETS (regno
) > 1
2384 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2385 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2388 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2389 maximal list size; look for overlaps in mode and select the largest. */
2391 add_to_mem_set_list (pbi
, mem
)
2392 struct propagate_block_info
*pbi
;
2397 /* We don't know how large a BLKmode store is, so we must not
2398 take them into consideration. */
2399 if (GET_MODE (mem
) == BLKmode
)
2402 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2404 rtx e
= XEXP (i
, 0);
2405 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2407 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2410 /* If we must store a copy of the mem, we can just modify
2411 the mode of the stored copy. */
2412 if (pbi
->flags
& PROP_AUTOINC
)
2413 PUT_MODE (e
, GET_MODE (mem
));
2422 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2425 /* Store a copy of mem, otherwise the address may be
2426 scrogged by find_auto_inc. */
2427 if (pbi
->flags
& PROP_AUTOINC
)
2428 mem
= shallow_copy_rtx (mem
);
2430 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2431 pbi
->mem_set_list_len
++;
2435 /* INSN references memory, possibly using autoincrement addressing modes.
2436 Find any entries on the mem_set_list that need to be invalidated due
2437 to an address change. */
2440 invalidate_mems_from_autoinc (px
, data
)
2445 struct propagate_block_info
*pbi
= data
;
2447 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2449 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2456 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2459 invalidate_mems_from_set (pbi
, exp
)
2460 struct propagate_block_info
*pbi
;
2463 rtx temp
= pbi
->mem_set_list
;
2464 rtx prev
= NULL_RTX
;
2469 next
= XEXP (temp
, 1);
2470 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2472 /* Splice this entry out of the list. */
2474 XEXP (prev
, 1) = next
;
2476 pbi
->mem_set_list
= next
;
2477 free_EXPR_LIST_node (temp
);
2478 pbi
->mem_set_list_len
--;
2486 /* Process the registers that are set within X. Their bits are set to
2487 1 in the regset DEAD, because they are dead prior to this insn.
2489 If INSN is nonzero, it is the insn being processed.
2491 FLAGS is the set of operations to perform. */
2494 mark_set_regs (pbi
, x
, insn
)
2495 struct propagate_block_info
*pbi
;
2498 rtx cond
= NULL_RTX
;
2503 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2505 if (REG_NOTE_KIND (link
) == REG_INC
)
2506 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2507 (GET_CODE (x
) == COND_EXEC
2508 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2512 switch (code
= GET_CODE (x
))
2516 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2520 cond
= COND_EXEC_TEST (x
);
2521 x
= COND_EXEC_CODE (x
);
2528 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2530 rtx sub
= XVECEXP (x
, 0, i
);
2531 switch (code
= GET_CODE (sub
))
2534 if (cond
!= NULL_RTX
)
2537 cond
= COND_EXEC_TEST (sub
);
2538 sub
= COND_EXEC_CODE (sub
);
2539 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2545 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2560 /* Process a single set, which appears in INSN. REG (which may not
2561 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2562 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2563 If the set is conditional (because it appear in a COND_EXEC), COND
2564 will be the condition. */
2567 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2568 struct propagate_block_info
*pbi
;
2570 rtx reg
, cond
, insn
;
2573 int regno_first
= -1, regno_last
= -1;
2574 unsigned long not_dead
= 0;
2577 /* Modifying just one hardware register of a multi-reg value or just a
2578 byte field of a register does not mean the value from before this insn
2579 is now dead. Of course, if it was dead after it's unused now. */
2581 switch (GET_CODE (reg
))
2584 /* Some targets place small structures in registers for return values of
2585 functions. We have to detect this case specially here to get correct
2586 flow information. */
2587 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2588 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2589 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2595 case STRICT_LOW_PART
:
2596 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2598 reg
= XEXP (reg
, 0);
2599 while (GET_CODE (reg
) == SUBREG
2600 || GET_CODE (reg
) == ZERO_EXTRACT
2601 || GET_CODE (reg
) == SIGN_EXTRACT
2602 || GET_CODE (reg
) == STRICT_LOW_PART
);
2603 if (GET_CODE (reg
) == MEM
)
2605 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2609 regno_last
= regno_first
= REGNO (reg
);
2610 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2611 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2615 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2617 enum machine_mode outer_mode
= GET_MODE (reg
);
2618 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2620 /* Identify the range of registers affected. This is moderately
2621 tricky for hard registers. See alter_subreg. */
2623 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2624 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2626 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2629 regno_last
= (regno_first
2630 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2632 /* Since we've just adjusted the register number ranges, make
2633 sure REG matches. Otherwise some_was_live will be clear
2634 when it shouldn't have been, and we'll create incorrect
2635 REG_UNUSED notes. */
2636 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2640 /* If the number of words in the subreg is less than the number
2641 of words in the full register, we have a well-defined partial
2642 set. Otherwise the high bits are undefined.
2644 This is only really applicable to pseudos, since we just took
2645 care of multi-word hard registers. */
2646 if (((GET_MODE_SIZE (outer_mode
)
2647 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2648 < ((GET_MODE_SIZE (inner_mode
)
2649 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2650 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2653 reg
= SUBREG_REG (reg
);
2657 reg
= SUBREG_REG (reg
);
2664 /* If this set is a MEM, then it kills any aliased writes.
2665 If this set is a REG, then it kills any MEMs which use the reg. */
2666 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2668 if (GET_CODE (reg
) == REG
)
2669 invalidate_mems_from_set (pbi
, reg
);
2671 /* If the memory reference had embedded side effects (autoincrement
2672 address modes. Then we may need to kill some entries on the
2674 if (insn
&& GET_CODE (reg
) == MEM
)
2675 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2677 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2678 /* ??? With more effort we could track conditional memory life. */
2680 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2683 if (GET_CODE (reg
) == REG
2684 && ! (regno_first
== FRAME_POINTER_REGNUM
2685 && (! reload_completed
|| frame_pointer_needed
))
2686 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2687 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2688 && (! reload_completed
|| frame_pointer_needed
))
2690 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2691 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2695 int some_was_live
= 0, some_was_dead
= 0;
2697 for (i
= regno_first
; i
<= regno_last
; ++i
)
2699 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2702 /* Order of the set operation matters here since both
2703 sets may be the same. */
2704 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2705 if (cond
!= NULL_RTX
2706 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2707 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2709 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2711 if (code
!= CLOBBER
)
2712 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2714 some_was_live
|= needed_regno
;
2715 some_was_dead
|= ! needed_regno
;
2718 #ifdef HAVE_conditional_execution
2719 /* Consider conditional death in deciding that the register needs
2721 if (some_was_live
&& ! not_dead
2722 /* The stack pointer is never dead. Well, not strictly true,
2723 but it's very difficult to tell from here. Hopefully
2724 combine_stack_adjustments will fix up the most egregious
2726 && regno_first
!= STACK_POINTER_REGNUM
)
2728 for (i
= regno_first
; i
<= regno_last
; ++i
)
2729 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2730 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2734 /* Additional data to record if this is the final pass. */
2735 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2736 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2739 int blocknum
= pbi
->bb
->index
;
2742 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2744 y
= pbi
->reg_next_use
[regno_first
];
2746 /* The next use is no longer next, since a store intervenes. */
2747 for (i
= regno_first
; i
<= regno_last
; ++i
)
2748 pbi
->reg_next_use
[i
] = 0;
2751 if (flags
& PROP_REG_INFO
)
2753 for (i
= regno_first
; i
<= regno_last
; ++i
)
2755 /* Count (weighted) references, stores, etc. This counts a
2756 register twice if it is modified, but that is correct. */
2757 REG_N_SETS (i
) += 1;
2758 REG_N_REFS (i
) += 1;
2759 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2761 /* The insns where a reg is live are normally counted
2762 elsewhere, but we want the count to include the insn
2763 where the reg is set, and the normal counting mechanism
2764 would not count it. */
2765 REG_LIVE_LENGTH (i
) += 1;
2768 /* If this is a hard reg, record this function uses the reg. */
2769 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2771 for (i
= regno_first
; i
<= regno_last
; i
++)
2772 regs_ever_live
[i
] = 1;
2776 /* Keep track of which basic blocks each reg appears in. */
2777 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2778 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2779 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2780 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2784 if (! some_was_dead
)
2786 if (flags
& PROP_LOG_LINKS
)
2788 /* Make a logical link from the next following insn
2789 that uses this register, back to this insn.
2790 The following insns have already been processed.
2792 We don't build a LOG_LINK for hard registers containing
2793 in ASM_OPERANDs. If these registers get replaced,
2794 we might wind up changing the semantics of the insn,
2795 even if reload can make what appear to be valid
2796 assignments later. */
2797 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2798 && (regno_first
>= FIRST_PSEUDO_REGISTER
2799 || asm_noperands (PATTERN (y
)) < 0))
2800 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2805 else if (! some_was_live
)
2807 if (flags
& PROP_REG_INFO
)
2808 REG_N_DEATHS (regno_first
) += 1;
2810 if (flags
& PROP_DEATH_NOTES
)
2812 /* Note that dead stores have already been deleted
2813 when possible. If we get here, we have found a
2814 dead store that cannot be eliminated (because the
2815 same insn does something useful). Indicate this
2816 by marking the reg being set as dying here. */
2818 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2823 if (flags
& PROP_DEATH_NOTES
)
2825 /* This is a case where we have a multi-word hard register
2826 and some, but not all, of the words of the register are
2827 needed in subsequent insns. Write REG_UNUSED notes
2828 for those parts that were not needed. This case should
2831 for (i
= regno_first
; i
<= regno_last
; ++i
)
2832 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2834 = alloc_EXPR_LIST (REG_UNUSED
,
2841 /* Mark the register as being dead. */
2843 /* The stack pointer is never dead. Well, not strictly true,
2844 but it's very difficult to tell from here. Hopefully
2845 combine_stack_adjustments will fix up the most egregious
2847 && regno_first
!= STACK_POINTER_REGNUM
)
2849 for (i
= regno_first
; i
<= regno_last
; ++i
)
2850 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2851 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2854 else if (GET_CODE (reg
) == REG
)
2856 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2857 pbi
->reg_next_use
[regno_first
] = 0;
2860 /* If this is the last pass and this is a SCRATCH, show it will be dying
2861 here and count it. */
2862 else if (GET_CODE (reg
) == SCRATCH
)
2864 if (flags
& PROP_DEATH_NOTES
)
2866 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2870 #ifdef HAVE_conditional_execution
2871 /* Mark REGNO conditionally dead.
2872 Return true if the register is now unconditionally dead. */
2875 mark_regno_cond_dead (pbi
, regno
, cond
)
2876 struct propagate_block_info
*pbi
;
2880 /* If this is a store to a predicate register, the value of the
2881 predicate is changing, we don't know that the predicate as seen
2882 before is the same as that seen after. Flush all dependent
2883 conditions from reg_cond_dead. This will make all such
2884 conditionally live registers unconditionally live. */
2885 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2886 flush_reg_cond_reg (pbi
, regno
);
2888 /* If this is an unconditional store, remove any conditional
2889 life that may have existed. */
2890 if (cond
== NULL_RTX
)
2891 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2894 splay_tree_node node
;
2895 struct reg_cond_life_info
*rcli
;
2898 /* Otherwise this is a conditional set. Record that fact.
2899 It may have been conditionally used, or there may be a
2900 subsequent set with a complimentary condition. */
2902 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2905 /* The register was unconditionally live previously.
2906 Record the current condition as the condition under
2907 which it is dead. */
2908 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2909 rcli
->condition
= cond
;
2910 rcli
->stores
= cond
;
2911 rcli
->orig_condition
= const0_rtx
;
2912 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2913 (splay_tree_value
) rcli
);
2915 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2917 /* Not unconditionally dead. */
2922 /* The register was conditionally live previously.
2923 Add the new condition to the old. */
2924 rcli
= (struct reg_cond_life_info
*) node
->value
;
2925 ncond
= rcli
->condition
;
2926 ncond
= ior_reg_cond (ncond
, cond
, 1);
2927 if (rcli
->stores
== const0_rtx
)
2928 rcli
->stores
= cond
;
2929 else if (rcli
->stores
!= const1_rtx
)
2930 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2932 /* If the register is now unconditionally dead, remove the entry
2933 in the splay_tree. A register is unconditionally dead if the
2934 dead condition ncond is true. A register is also unconditionally
2935 dead if the sum of all conditional stores is an unconditional
2936 store (stores is true), and the dead condition is identically the
2937 same as the original dead condition initialized at the end of
2938 the block. This is a pointer compare, not an rtx_equal_p
2940 if (ncond
== const1_rtx
2941 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2942 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2945 rcli
->condition
= ncond
;
2947 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2949 /* Not unconditionally dead. */
2958 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2961 free_reg_cond_life_info (value
)
2962 splay_tree_value value
;
2964 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2968 /* Helper function for flush_reg_cond_reg. */
2971 flush_reg_cond_reg_1 (node
, data
)
2972 splay_tree_node node
;
2975 struct reg_cond_life_info
*rcli
;
2976 int *xdata
= (int *) data
;
2977 unsigned int regno
= xdata
[0];
2979 /* Don't need to search if last flushed value was farther on in
2980 the in-order traversal. */
2981 if (xdata
[1] >= (int) node
->key
)
2984 /* Splice out portions of the expression that refer to regno. */
2985 rcli
= (struct reg_cond_life_info
*) node
->value
;
2986 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2987 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2988 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2990 /* If the entire condition is now false, signal the node to be removed. */
2991 if (rcli
->condition
== const0_rtx
)
2993 xdata
[1] = node
->key
;
2996 else if (rcli
->condition
== const1_rtx
)
3002 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3005 flush_reg_cond_reg (pbi
, regno
)
3006 struct propagate_block_info
*pbi
;
3013 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3014 flush_reg_cond_reg_1
, pair
) == -1)
3015 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3017 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3020 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3021 For ior/and, the ADD flag determines whether we want to add the new
3022 condition X to the old one unconditionally. If it is zero, we will
3023 only return a new expression if X allows us to simplify part of
3024 OLD, otherwise we return NULL to the caller.
3025 If ADD is nonzero, we will return a new condition in all cases. The
3026 toplevel caller of one of these functions should always pass 1 for
3030 ior_reg_cond (old
, x
, add
)
3036 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3038 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3039 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3040 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3042 if (GET_CODE (x
) == GET_CODE (old
)
3043 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3047 return gen_rtx_IOR (0, old
, x
);
3050 switch (GET_CODE (old
))
3053 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3054 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3055 if (op0
!= NULL
|| op1
!= NULL
)
3057 if (op0
== const0_rtx
)
3058 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3059 if (op1
== const0_rtx
)
3060 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3061 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3064 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3065 else if (rtx_equal_p (x
, op0
))
3066 /* (x | A) | x ~ (x | A). */
3069 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3070 else if (rtx_equal_p (x
, op1
))
3071 /* (A | x) | x ~ (A | x). */
3073 return gen_rtx_IOR (0, op0
, op1
);
3077 return gen_rtx_IOR (0, old
, x
);
3080 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3081 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3082 if (op0
!= NULL
|| op1
!= NULL
)
3084 if (op0
== const1_rtx
)
3085 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3086 if (op1
== const1_rtx
)
3087 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3088 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3091 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3092 else if (rtx_equal_p (x
, op0
))
3093 /* (x & A) | x ~ x. */
3096 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3097 else if (rtx_equal_p (x
, op1
))
3098 /* (A & x) | x ~ x. */
3100 return gen_rtx_AND (0, op0
, op1
);
3104 return gen_rtx_IOR (0, old
, x
);
3107 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3109 return not_reg_cond (op0
);
3112 return gen_rtx_IOR (0, old
, x
);
3123 enum rtx_code x_code
;
3125 if (x
== const0_rtx
)
3127 else if (x
== const1_rtx
)
3129 x_code
= GET_CODE (x
);
3132 if (GET_RTX_CLASS (x_code
) == '<'
3133 && GET_CODE (XEXP (x
, 0)) == REG
)
3135 if (XEXP (x
, 1) != const0_rtx
)
3138 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3139 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3141 return gen_rtx_NOT (0, x
);
3145 and_reg_cond (old
, x
, add
)
3151 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3153 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3154 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3155 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3157 if (GET_CODE (x
) == GET_CODE (old
)
3158 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3162 return gen_rtx_AND (0, old
, x
);
3165 switch (GET_CODE (old
))
3168 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3169 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3170 if (op0
!= NULL
|| op1
!= NULL
)
3172 if (op0
== const0_rtx
)
3173 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3174 if (op1
== const0_rtx
)
3175 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3176 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3179 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3180 else if (rtx_equal_p (x
, op0
))
3181 /* (x | A) & x ~ x. */
3184 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3185 else if (rtx_equal_p (x
, op1
))
3186 /* (A | x) & x ~ x. */
3188 return gen_rtx_IOR (0, op0
, op1
);
3192 return gen_rtx_AND (0, old
, x
);
3195 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3196 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3197 if (op0
!= NULL
|| op1
!= NULL
)
3199 if (op0
== const1_rtx
)
3200 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3201 if (op1
== const1_rtx
)
3202 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3203 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3206 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3207 else if (rtx_equal_p (x
, op0
))
3208 /* (x & A) & x ~ (x & A). */
3211 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3212 else if (rtx_equal_p (x
, op1
))
3213 /* (A & x) & x ~ (A & x). */
3215 return gen_rtx_AND (0, op0
, op1
);
3219 return gen_rtx_AND (0, old
, x
);
3222 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3224 return not_reg_cond (op0
);
3227 return gen_rtx_AND (0, old
, x
);
3234 /* Given a condition X, remove references to reg REGNO and return the
3235 new condition. The removal will be done so that all conditions
3236 involving REGNO are considered to evaluate to false. This function
3237 is used when the value of REGNO changes. */
3240 elim_reg_cond (x
, regno
)
3246 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3248 if (REGNO (XEXP (x
, 0)) == regno
)
3253 switch (GET_CODE (x
))
3256 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3257 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3258 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3260 if (op0
== const1_rtx
)
3262 if (op1
== const1_rtx
)
3264 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3266 return gen_rtx_AND (0, op0
, op1
);
3269 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3270 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3271 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3273 if (op0
== const0_rtx
)
3275 if (op1
== const0_rtx
)
3277 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3279 return gen_rtx_IOR (0, op0
, op1
);
3282 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3283 if (op0
== const0_rtx
)
3285 if (op0
== const1_rtx
)
3287 if (op0
!= XEXP (x
, 0))
3288 return not_reg_cond (op0
);
3295 #endif /* HAVE_conditional_execution */
3299 /* Try to substitute the auto-inc expression INC as the address inside
3300 MEM which occurs in INSN. Currently, the address of MEM is an expression
3301 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3302 that has a single set whose source is a PLUS of INCR_REG and something
3306 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3307 struct propagate_block_info
*pbi
;
3308 rtx inc
, insn
, mem
, incr
, incr_reg
;
3310 int regno
= REGNO (incr_reg
);
3311 rtx set
= single_set (incr
);
3312 rtx q
= SET_DEST (set
);
3313 rtx y
= SET_SRC (set
);
3314 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3316 /* Make sure this reg appears only once in this insn. */
3317 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3320 if (dead_or_set_p (incr
, incr_reg
)
3321 /* Mustn't autoinc an eliminable register. */
3322 && (regno
>= FIRST_PSEUDO_REGISTER
3323 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3325 /* This is the simple case. Try to make the auto-inc. If
3326 we can't, we are done. Otherwise, we will do any
3327 needed updates below. */
3328 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3331 else if (GET_CODE (q
) == REG
3332 /* PREV_INSN used here to check the semi-open interval
3334 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3335 /* We must also check for sets of q as q may be
3336 a call clobbered hard register and there may
3337 be a call between PREV_INSN (insn) and incr. */
3338 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3340 /* We have *p followed sometime later by q = p+size.
3341 Both p and q must be live afterward,
3342 and q is not used between INSN and its assignment.
3343 Change it to q = p, ...*q..., q = q+size.
3344 Then fall into the usual case. */
3348 emit_move_insn (q
, incr_reg
);
3349 insns
= get_insns ();
3352 /* If we can't make the auto-inc, or can't make the
3353 replacement into Y, exit. There's no point in making
3354 the change below if we can't do the auto-inc and doing
3355 so is not correct in the pre-inc case. */
3358 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3359 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3360 if (! apply_change_group ())
3363 /* We now know we'll be doing this change, so emit the
3364 new insn(s) and do the updates. */
3365 emit_insn_before (insns
, insn
);
3367 if (pbi
->bb
->head
== insn
)
3368 pbi
->bb
->head
= insns
;
3370 /* INCR will become a NOTE and INSN won't contain a
3371 use of INCR_REG. If a use of INCR_REG was just placed in
3372 the insn before INSN, make that the next use.
3373 Otherwise, invalidate it. */
3374 if (GET_CODE (PREV_INSN (insn
)) == INSN
3375 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3376 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3377 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3379 pbi
->reg_next_use
[regno
] = 0;
3384 /* REGNO is now used in INCR which is below INSN, but
3385 it previously wasn't live here. If we don't mark
3386 it as live, we'll put a REG_DEAD note for it
3387 on this insn, which is incorrect. */
3388 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3390 /* If there are any calls between INSN and INCR, show
3391 that REGNO now crosses them. */
3392 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3393 if (GET_CODE (temp
) == CALL_INSN
)
3394 REG_N_CALLS_CROSSED (regno
)++;
3396 /* Invalidate alias info for Q since we just changed its value. */
3397 clear_reg_alias_info (q
);
3402 /* If we haven't returned, it means we were able to make the
3403 auto-inc, so update the status. First, record that this insn
3404 has an implicit side effect. */
3406 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3408 /* Modify the old increment-insn to simply copy
3409 the already-incremented value of our register. */
3410 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3413 /* If that makes it a no-op (copying the register into itself) delete
3414 it so it won't appear to be a "use" and a "set" of this
3416 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3418 /* If the original source was dead, it's dead now. */
3421 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3423 remove_note (incr
, note
);
3424 if (XEXP (note
, 0) != incr_reg
)
3425 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3428 PUT_CODE (incr
, NOTE
);
3429 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3430 NOTE_SOURCE_FILE (incr
) = 0;
3433 if (regno
>= FIRST_PSEUDO_REGISTER
)
3435 /* Count an extra reference to the reg. When a reg is
3436 incremented, spilling it is worse, so we want to make
3437 that less likely. */
3438 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3440 /* Count the increment as a setting of the register,
3441 even though it isn't a SET in rtl. */
3442 REG_N_SETS (regno
)++;
3446 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3450 find_auto_inc (pbi
, x
, insn
)
3451 struct propagate_block_info
*pbi
;
3455 rtx addr
= XEXP (x
, 0);
3456 HOST_WIDE_INT offset
= 0;
3457 rtx set
, y
, incr
, inc_val
;
3459 int size
= GET_MODE_SIZE (GET_MODE (x
));
3461 if (GET_CODE (insn
) == JUMP_INSN
)
3464 /* Here we detect use of an index register which might be good for
3465 postincrement, postdecrement, preincrement, or predecrement. */
3467 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3468 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3470 if (GET_CODE (addr
) != REG
)
3473 regno
= REGNO (addr
);
3475 /* Is the next use an increment that might make auto-increment? */
3476 incr
= pbi
->reg_next_use
[regno
];
3477 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3479 set
= single_set (incr
);
3480 if (set
== 0 || GET_CODE (set
) != SET
)
3484 if (GET_CODE (y
) != PLUS
)
3487 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3488 inc_val
= XEXP (y
, 1);
3489 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3490 inc_val
= XEXP (y
, 0);
3494 if (GET_CODE (inc_val
) == CONST_INT
)
3496 if (HAVE_POST_INCREMENT
3497 && (INTVAL (inc_val
) == size
&& offset
== 0))
3498 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3500 else if (HAVE_POST_DECREMENT
3501 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3502 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3504 else if (HAVE_PRE_INCREMENT
3505 && (INTVAL (inc_val
) == size
&& offset
== size
))
3506 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3508 else if (HAVE_PRE_DECREMENT
3509 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3510 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3512 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3513 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3514 gen_rtx_PLUS (Pmode
,
3517 insn
, x
, incr
, addr
);
3519 else if (GET_CODE (inc_val
) == REG
3520 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3524 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3525 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3526 gen_rtx_PLUS (Pmode
,
3529 insn
, x
, incr
, addr
);
3533 #endif /* AUTO_INC_DEC */
3536 mark_used_reg (pbi
, reg
, cond
, insn
)
3537 struct propagate_block_info
*pbi
;
3539 rtx cond ATTRIBUTE_UNUSED
;
3542 unsigned int regno_first
, regno_last
, i
;
3543 int some_was_live
, some_was_dead
, some_not_set
;
3545 regno_last
= regno_first
= REGNO (reg
);
3546 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3547 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3549 /* Find out if any of this register is live after this instruction. */
3550 some_was_live
= some_was_dead
= 0;
3551 for (i
= regno_first
; i
<= regno_last
; ++i
)
3553 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3554 some_was_live
|= needed_regno
;
3555 some_was_dead
|= ! needed_regno
;
3558 /* Find out if any of the register was set this insn. */
3560 for (i
= regno_first
; i
<= regno_last
; ++i
)
3561 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3563 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3565 /* Record where each reg is used, so when the reg is set we know
3566 the next insn that uses it. */
3567 pbi
->reg_next_use
[regno_first
] = insn
;
3570 if (pbi
->flags
& PROP_REG_INFO
)
3572 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3574 /* If this is a register we are going to try to eliminate,
3575 don't mark it live here. If we are successful in
3576 eliminating it, it need not be live unless it is used for
3577 pseudos, in which case it will have been set live when it
3578 was allocated to the pseudos. If the register will not
3579 be eliminated, reload will set it live at that point.
3581 Otherwise, record that this function uses this register. */
3582 /* ??? The PPC backend tries to "eliminate" on the pic
3583 register to itself. This should be fixed. In the mean
3584 time, hack around it. */
3586 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3587 && (regno_first
== FRAME_POINTER_REGNUM
3588 || regno_first
== ARG_POINTER_REGNUM
)))
3589 for (i
= regno_first
; i
<= regno_last
; ++i
)
3590 regs_ever_live
[i
] = 1;
3594 /* Keep track of which basic block each reg appears in. */
3596 int blocknum
= pbi
->bb
->index
;
3597 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3598 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3599 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3600 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3602 /* Count (weighted) number of uses of each reg. */
3603 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3604 REG_N_REFS (regno_first
)++;
3608 /* Record and count the insns in which a reg dies. If it is used in
3609 this insn and was dead below the insn then it dies in this insn.
3610 If it was set in this insn, we do not make a REG_DEAD note;
3611 likewise if we already made such a note. */
3612 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3616 /* Check for the case where the register dying partially
3617 overlaps the register set by this insn. */
3618 if (regno_first
!= regno_last
)
3619 for (i
= regno_first
; i
<= regno_last
; ++i
)
3620 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3622 /* If none of the words in X is needed, make a REG_DEAD note.
3623 Otherwise, we must make partial REG_DEAD notes. */
3624 if (! some_was_live
)
3626 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3627 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3629 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3631 if (pbi
->flags
& PROP_REG_INFO
)
3632 REG_N_DEATHS (regno_first
)++;
3636 /* Don't make a REG_DEAD note for a part of a register
3637 that is set in the insn. */
3638 for (i
= regno_first
; i
<= regno_last
; ++i
)
3639 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3640 && ! dead_or_set_regno_p (insn
, i
))
3642 = alloc_EXPR_LIST (REG_DEAD
,
3648 /* Mark the register as being live. */
3649 for (i
= regno_first
; i
<= regno_last
; ++i
)
3651 #ifdef HAVE_conditional_execution
3652 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3655 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3657 #ifdef HAVE_conditional_execution
3658 /* If this is a conditional use, record that fact. If it is later
3659 conditionally set, we'll know to kill the register. */
3660 if (cond
!= NULL_RTX
)
3662 splay_tree_node node
;
3663 struct reg_cond_life_info
*rcli
;
3668 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3671 /* The register was unconditionally live previously.
3672 No need to do anything. */
3676 /* The register was conditionally live previously.
3677 Subtract the new life cond from the old death cond. */
3678 rcli
= (struct reg_cond_life_info
*) node
->value
;
3679 ncond
= rcli
->condition
;
3680 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3682 /* If the register is now unconditionally live,
3683 remove the entry in the splay_tree. */
3684 if (ncond
== const0_rtx
)
3685 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3688 rcli
->condition
= ncond
;
3689 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3690 REGNO (XEXP (cond
, 0)));
3696 /* The register was not previously live at all. Record
3697 the condition under which it is still dead. */
3698 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3699 rcli
->condition
= not_reg_cond (cond
);
3700 rcli
->stores
= const0_rtx
;
3701 rcli
->orig_condition
= const0_rtx
;
3702 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3703 (splay_tree_value
) rcli
);
3705 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3708 else if (this_was_live
)
3710 /* The register may have been conditionally live previously, but
3711 is now unconditionally live. Remove it from the conditionally
3712 dead list, so that a conditional set won't cause us to think
3714 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3720 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3721 This is done assuming the registers needed from X are those that
3722 have 1-bits in PBI->REG_LIVE.
3724 INSN is the containing instruction. If INSN is dead, this function
3728 mark_used_regs (pbi
, x
, cond
, insn
)
3729 struct propagate_block_info
*pbi
;
3734 int flags
= pbi
->flags
;
3739 code
= GET_CODE (x
);
3760 /* If we are clobbering a MEM, mark any registers inside the address
3762 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3763 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3767 /* Don't bother watching stores to mems if this is not the
3768 final pass. We'll not be deleting dead stores this round. */
3769 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3771 /* Invalidate the data for the last MEM stored, but only if MEM is
3772 something that can be stored into. */
3773 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3774 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3775 /* Needn't clear the memory set list. */
3779 rtx temp
= pbi
->mem_set_list
;
3780 rtx prev
= NULL_RTX
;
3785 next
= XEXP (temp
, 1);
3786 if (anti_dependence (XEXP (temp
, 0), x
))
3788 /* Splice temp out of the list. */
3790 XEXP (prev
, 1) = next
;
3792 pbi
->mem_set_list
= next
;
3793 free_EXPR_LIST_node (temp
);
3794 pbi
->mem_set_list_len
--;
3802 /* If the memory reference had embedded side effects (autoincrement
3803 address modes. Then we may need to kill some entries on the
3806 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3810 if (flags
& PROP_AUTOINC
)
3811 find_auto_inc (pbi
, x
, insn
);
3816 #ifdef CLASS_CANNOT_CHANGE_MODE
3817 if (GET_CODE (SUBREG_REG (x
)) == REG
3818 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3819 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3820 GET_MODE (SUBREG_REG (x
))))
3821 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3824 /* While we're here, optimize this case. */
3826 if (GET_CODE (x
) != REG
)
3831 /* See a register other than being set => mark it as needed. */
3832 mark_used_reg (pbi
, x
, cond
, insn
);
3837 rtx testreg
= SET_DEST (x
);
3840 /* If storing into MEM, don't show it as being used. But do
3841 show the address as being used. */
3842 if (GET_CODE (testreg
) == MEM
)
3845 if (flags
& PROP_AUTOINC
)
3846 find_auto_inc (pbi
, testreg
, insn
);
3848 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3849 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3853 /* Storing in STRICT_LOW_PART is like storing in a reg
3854 in that this SET might be dead, so ignore it in TESTREG.
3855 but in some other ways it is like using the reg.
3857 Storing in a SUBREG or a bit field is like storing the entire
3858 register in that if the register's value is not used
3859 then this SET is not needed. */
3860 while (GET_CODE (testreg
) == STRICT_LOW_PART
3861 || GET_CODE (testreg
) == ZERO_EXTRACT
3862 || GET_CODE (testreg
) == SIGN_EXTRACT
3863 || GET_CODE (testreg
) == SUBREG
)
3865 #ifdef CLASS_CANNOT_CHANGE_MODE
3866 if (GET_CODE (testreg
) == SUBREG
3867 && GET_CODE (SUBREG_REG (testreg
)) == REG
3868 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3869 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3870 GET_MODE (testreg
)))
3871 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3874 /* Modifying a single register in an alternate mode
3875 does not use any of the old value. But these other
3876 ways of storing in a register do use the old value. */
3877 if (GET_CODE (testreg
) == SUBREG
3878 && !((REG_BYTES (SUBREG_REG (testreg
))
3879 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3880 > (REG_BYTES (testreg
)
3881 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3886 testreg
= XEXP (testreg
, 0);
3889 /* If this is a store into a register or group of registers,
3890 recursively scan the value being stored. */
3892 if ((GET_CODE (testreg
) == PARALLEL
3893 && GET_MODE (testreg
) == BLKmode
)
3894 || (GET_CODE (testreg
) == REG
3895 && (regno
= REGNO (testreg
),
3896 ! (regno
== FRAME_POINTER_REGNUM
3897 && (! reload_completed
|| frame_pointer_needed
)))
3898 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3899 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3900 && (! reload_completed
|| frame_pointer_needed
))
3902 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3903 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3908 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3909 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3916 case UNSPEC_VOLATILE
:
3920 /* Traditional and volatile asm instructions must be considered to use
3921 and clobber all hard registers, all pseudo-registers and all of
3922 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3924 Consider for instance a volatile asm that changes the fpu rounding
3925 mode. An insn should not be moved across this even if it only uses
3926 pseudo-regs because it might give an incorrectly rounded result.
3928 ?!? Unfortunately, marking all hard registers as live causes massive
3929 problems for the register allocator and marking all pseudos as live
3930 creates mountains of uninitialized variable warnings.
3932 So for now, just clear the memory set list and mark any regs
3933 we can find in ASM_OPERANDS as used. */
3934 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3936 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3937 pbi
->mem_set_list_len
= 0;
3940 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3941 We can not just fall through here since then we would be confused
3942 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3943 traditional asms unlike their normal usage. */
3944 if (code
== ASM_OPERANDS
)
3948 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3949 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3955 if (cond
!= NULL_RTX
)
3958 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3960 cond
= COND_EXEC_TEST (x
);
3961 x
= COND_EXEC_CODE (x
);
3965 /* We _do_not_ want to scan operands of phi nodes. Operands of
3966 a phi function are evaluated only when control reaches this
3967 block along a particular edge. Therefore, regs that appear
3968 as arguments to phi should not be added to the global live at
3976 /* Recursively scan the operands of this expression. */
3979 const char * const fmt
= GET_RTX_FORMAT (code
);
3982 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3986 /* Tail recursive case: save a function call level. */
3992 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3994 else if (fmt
[i
] == 'E')
3997 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3998 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4007 try_pre_increment_1 (pbi
, insn
)
4008 struct propagate_block_info
*pbi
;
4011 /* Find the next use of this reg. If in same basic block,
4012 make it do pre-increment or pre-decrement if appropriate. */
4013 rtx x
= single_set (insn
);
4014 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4015 * INTVAL (XEXP (SET_SRC (x
), 1)));
4016 int regno
= REGNO (SET_DEST (x
));
4017 rtx y
= pbi
->reg_next_use
[regno
];
4019 && SET_DEST (x
) != stack_pointer_rtx
4020 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4021 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4022 mode would be better. */
4023 && ! dead_or_set_p (y
, SET_DEST (x
))
4024 && try_pre_increment (y
, SET_DEST (x
), amount
))
4026 /* We have found a suitable auto-increment and already changed
4027 insn Y to do it. So flush this increment instruction. */
4028 propagate_block_delete_insn (insn
);
4030 /* Count a reference to this reg for the increment insn we are
4031 deleting. When a reg is incremented, spilling it is worse,
4032 so we want to make that less likely. */
4033 if (regno
>= FIRST_PSEUDO_REGISTER
)
4035 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4036 REG_N_SETS (regno
)++;
4039 /* Flush any remembered memories depending on the value of
4040 the incremented register. */
4041 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4048 /* Try to change INSN so that it does pre-increment or pre-decrement
4049 addressing on register REG in order to add AMOUNT to REG.
4050 AMOUNT is negative for pre-decrement.
4051 Returns 1 if the change could be made.
4052 This checks all about the validity of the result of modifying INSN. */
4055 try_pre_increment (insn
, reg
, amount
)
4057 HOST_WIDE_INT amount
;
4061 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4062 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4064 /* Nonzero if we can try to make a post-increment or post-decrement.
4065 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4066 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4067 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4070 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4073 /* From the sign of increment, see which possibilities are conceivable
4074 on this target machine. */
4075 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4077 if (HAVE_POST_INCREMENT
&& amount
> 0)
4080 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4082 if (HAVE_POST_DECREMENT
&& amount
< 0)
4085 if (! (pre_ok
|| post_ok
))
4088 /* It is not safe to add a side effect to a jump insn
4089 because if the incremented register is spilled and must be reloaded
4090 there would be no way to store the incremented value back in memory. */
4092 if (GET_CODE (insn
) == JUMP_INSN
)
4097 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4098 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4100 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4104 if (use
== 0 || use
== (rtx
) (size_t) 1)
4107 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4110 /* See if this combination of instruction and addressing mode exists. */
4111 if (! validate_change (insn
, &XEXP (use
, 0),
4112 gen_rtx_fmt_e (amount
> 0
4113 ? (do_post
? POST_INC
: PRE_INC
)
4114 : (do_post
? POST_DEC
: PRE_DEC
),
4118 /* Record that this insn now has an implicit side effect on X. */
4119 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4123 #endif /* AUTO_INC_DEC */
4125 /* Find the place in the rtx X where REG is used as a memory address.
4126 Return the MEM rtx that so uses it.
4127 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4128 (plus REG (const_int PLUSCONST)).
4130 If such an address does not appear, return 0.
4131 If REG appears more than once, or is used other than in such an address,
4135 find_use_as_address (x
, reg
, plusconst
)
4138 HOST_WIDE_INT plusconst
;
4140 enum rtx_code code
= GET_CODE (x
);
4141 const char * const fmt
= GET_RTX_FORMAT (code
);
4146 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4149 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4150 && XEXP (XEXP (x
, 0), 0) == reg
4151 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4152 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4155 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4157 /* If REG occurs inside a MEM used in a bit-field reference,
4158 that is unacceptable. */
4159 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4160 return (rtx
) (size_t) 1;
4164 return (rtx
) (size_t) 1;
4166 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4170 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4174 return (rtx
) (size_t) 1;
4176 else if (fmt
[i
] == 'E')
4179 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4181 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4185 return (rtx
) (size_t) 1;
4193 /* Write information about registers and basic blocks into FILE.
4194 This is part of making a debugging dump. */
4197 dump_regset (r
, outf
)
4204 fputs (" (nil)", outf
);
4208 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4210 fprintf (outf
, " %d", i
);
4211 if (i
< FIRST_PSEUDO_REGISTER
)
4212 fprintf (outf
, " [%s]",
4217 /* Print a human-reaable representation of R on the standard error
4218 stream. This function is designed to be used from within the
4225 dump_regset (r
, stderr
);
4226 putc ('\n', stderr
);
4229 /* Recompute register set/reference counts immediately prior to register
4232 This avoids problems with set/reference counts changing to/from values
4233 which have special meanings to the register allocators.
4235 Additionally, the reference counts are the primary component used by the
4236 register allocators to prioritize pseudos for allocation to hard regs.
4237 More accurate reference counts generally lead to better register allocation.
4239 F is the first insn to be scanned.
4241 LOOP_STEP denotes how much loop_depth should be incremented per
4242 loop nesting level in order to increase the ref count more for
4243 references in a loop.
4245 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4246 possibly other information which is used by the register allocators. */
4249 recompute_reg_usage (f
, loop_step
)
4250 rtx f ATTRIBUTE_UNUSED
;
4251 int loop_step ATTRIBUTE_UNUSED
;
4253 allocate_reg_life_data ();
4254 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4257 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4258 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4259 of the number of registers that died. */
4262 count_or_remove_death_notes (blocks
, kill
)
4269 FOR_EACH_BB_REVERSE (bb
)
4273 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4276 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4280 rtx
*pprev
= ®_NOTES (insn
);
4285 switch (REG_NOTE_KIND (link
))
4288 if (GET_CODE (XEXP (link
, 0)) == REG
)
4290 rtx reg
= XEXP (link
, 0);
4293 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4296 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4304 rtx next
= XEXP (link
, 1);
4305 free_EXPR_LIST_node (link
);
4306 *pprev
= link
= next
;
4312 pprev
= &XEXP (link
, 1);
4319 if (insn
== bb
->end
)
4326 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4327 if blocks is NULL. */
4330 clear_log_links (blocks
)
4338 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4340 free_INSN_LIST_list (&LOG_LINKS (insn
));
4343 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4345 basic_block bb
= BASIC_BLOCK (i
);
4347 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4348 insn
= NEXT_INSN (insn
))
4350 free_INSN_LIST_list (&LOG_LINKS (insn
));
4354 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4355 correspond to the hard registers, if any, set in that map. This
4356 could be done far more efficiently by having all sorts of special-cases
4357 with moving single words, but probably isn't worth the trouble. */
4360 reg_set_to_hard_reg_set (to
, from
)
4366 EXECUTE_IF_SET_IN_BITMAP
4369 if (i
>= FIRST_PSEUDO_REGISTER
)
4371 SET_HARD_REG_BIT (*to
, i
);