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
123 #include "coretypes.h"
128 #include "hard-reg-set.h"
129 #include "basic-block.h"
130 #include "insn-config.h"
134 #include "function.h"
143 #include "splay-tree.h"
145 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
146 the stack pointer does not matter. The value is tested only in
147 functions that have frame pointers.
148 No definition is equivalent to always zero. */
149 #ifndef EXIT_IGNORE_STACK
150 #define EXIT_IGNORE_STACK 0
153 #ifndef HAVE_epilogue
154 #define HAVE_epilogue 0
156 #ifndef HAVE_prologue
157 #define HAVE_prologue 0
159 #ifndef HAVE_sibcall_epilogue
160 #define HAVE_sibcall_epilogue 0
164 #define LOCAL_REGNO(REGNO) 0
166 #ifndef EPILOGUE_USES
167 #define EPILOGUE_USES(REGNO) 0
170 #define EH_USES(REGNO) 0
173 #ifdef HAVE_conditional_execution
174 #ifndef REVERSE_CONDEXEC_PREDICATES_P
175 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
179 /* Nonzero if the second flow pass has completed. */
182 /* Maximum register number used in this function, plus one. */
186 /* Indexed by n, giving various register information */
188 varray_type reg_n_info
;
190 /* Size of a regset for the current function,
191 in (1) bytes and (2) elements. */
196 /* Regset of regs live when calls to `setjmp'-like functions happen. */
197 /* ??? Does this exist only for the setjmp-clobbered warning message? */
199 regset regs_live_at_setjmp
;
201 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
202 that have to go in the same hard reg.
203 The first two regs in the list are a pair, and the next two
204 are another pair, etc. */
207 /* Callback that determines if it's ok for a function to have no
208 noreturn attribute. */
209 int (*lang_missing_noreturn_ok_p
) PARAMS ((tree
));
211 /* Set of registers that may be eliminable. These are handled specially
212 in updating regs_ever_live. */
214 static HARD_REG_SET elim_reg_set
;
216 /* Holds information for tracking conditional register life information. */
217 struct reg_cond_life_info
219 /* A boolean expression of conditions under which a register is dead. */
221 /* Conditions under which a register is dead at the basic block end. */
224 /* A boolean expression of conditions under which a register has been
228 /* ??? Could store mask of bytes that are dead, so that we could finally
229 track lifetimes of multi-word registers accessed via subregs. */
232 /* For use in communicating between propagate_block and its subroutines.
233 Holds all information needed to compute life and def-use information. */
235 struct propagate_block_info
237 /* The basic block we're considering. */
240 /* Bit N is set if register N is conditionally or unconditionally live. */
243 /* Bit N is set if register N is set this insn. */
246 /* Element N is the next insn that uses (hard or pseudo) register N
247 within the current basic block; or zero, if there is no such insn. */
250 /* Contains a list of all the MEMs we are tracking for dead store
254 /* If non-null, record the set of registers set unconditionally in the
258 /* If non-null, record the set of registers set conditionally in the
260 regset cond_local_set
;
262 #ifdef HAVE_conditional_execution
263 /* Indexed by register number, holds a reg_cond_life_info for each
264 register that is not unconditionally live or dead. */
265 splay_tree reg_cond_dead
;
267 /* Bit N is set if register N is in an expression in reg_cond_dead. */
271 /* The length of mem_set_list. */
272 int mem_set_list_len
;
274 /* Nonzero if the value of CC0 is live. */
277 /* Flags controlling the set of information propagate_block collects. */
281 /* Number of dead insns removed. */
284 /* Maximum length of pbi->mem_set_list before we start dropping
285 new elements on the floor. */
286 #define MAX_MEM_SET_LIST_LEN 100
288 /* Forward declarations */
289 static int verify_wide_reg_1
PARAMS ((rtx
*, void *));
290 static void verify_wide_reg
PARAMS ((int, basic_block
));
291 static void verify_local_live_at_start
PARAMS ((regset
, basic_block
));
292 static void notice_stack_pointer_modification_1
PARAMS ((rtx
, rtx
, void *));
293 static void notice_stack_pointer_modification
PARAMS ((rtx
));
294 static void mark_reg
PARAMS ((rtx
, void *));
295 static void mark_regs_live_at_end
PARAMS ((regset
));
296 static int set_phi_alternative_reg
PARAMS ((rtx
, int, int, void *));
297 static void calculate_global_regs_live
PARAMS ((sbitmap
, sbitmap
, int));
298 static void propagate_block_delete_insn
PARAMS ((rtx
));
299 static rtx propagate_block_delete_libcall
PARAMS ((rtx
, rtx
));
300 static int insn_dead_p
PARAMS ((struct propagate_block_info
*,
302 static int libcall_dead_p
PARAMS ((struct propagate_block_info
*,
304 static void mark_set_regs
PARAMS ((struct propagate_block_info
*,
306 static void mark_set_1
PARAMS ((struct propagate_block_info
*,
307 enum rtx_code
, rtx
, rtx
,
309 static int find_regno_partial
PARAMS ((rtx
*, void *));
311 #ifdef HAVE_conditional_execution
312 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
314 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
315 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
316 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
318 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
319 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
320 static rtx not_reg_cond
PARAMS ((rtx
));
321 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
324 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
325 rtx
, rtx
, rtx
, rtx
, rtx
));
326 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
328 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
330 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
332 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
334 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
336 void dump_flow_info
PARAMS ((FILE *));
337 void debug_flow_info
PARAMS ((void));
338 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
340 static int invalidate_mems_from_autoinc
PARAMS ((rtx
*, void *));
341 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
343 static void clear_log_links
PARAMS ((sbitmap
));
347 check_function_return_warnings ()
349 if (warn_missing_noreturn
350 && !TREE_THIS_VOLATILE (cfun
->decl
)
351 && EXIT_BLOCK_PTR
->pred
== NULL
352 && (lang_missing_noreturn_ok_p
353 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
354 warning ("function might be possible candidate for attribute `noreturn'");
356 /* If we have a path to EXIT, then we do return. */
357 if (TREE_THIS_VOLATILE (cfun
->decl
)
358 && EXIT_BLOCK_PTR
->pred
!= NULL
)
359 warning ("`noreturn' function does return");
361 /* If the clobber_return_insn appears in some basic block, then we
362 do reach the end without returning a value. */
363 else if (warn_return_type
364 && cfun
->x_clobber_return_insn
!= NULL
365 && EXIT_BLOCK_PTR
->pred
!= NULL
)
367 int max_uid
= get_max_uid ();
369 /* If clobber_return_insn was excised by jump1, then renumber_insns
370 can make max_uid smaller than the number still recorded in our rtx.
371 That's fine, since this is a quick way of verifying that the insn
372 is no longer in the chain. */
373 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
377 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
378 if (insn
== cfun
->x_clobber_return_insn
)
380 warning ("control reaches end of non-void function");
387 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
388 note associated with the BLOCK. */
391 first_insn_after_basic_block_note (block
)
396 /* Get the first instruction in the block. */
399 if (insn
== NULL_RTX
)
401 if (GET_CODE (insn
) == CODE_LABEL
)
402 insn
= NEXT_INSN (insn
);
403 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
406 return NEXT_INSN (insn
);
409 /* Perform data flow analysis.
410 F is the first insn of the function; FLAGS is a set of PROP_* flags
411 to be used in accumulating flow info. */
414 life_analysis (f
, file
, flags
)
419 #ifdef ELIMINABLE_REGS
421 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
424 /* Record which registers will be eliminated. We use this in
427 CLEAR_HARD_REG_SET (elim_reg_set
);
429 #ifdef ELIMINABLE_REGS
430 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
431 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
433 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
437 #ifdef CANNOT_CHANGE_MODE_CLASS
438 if (flags
& PROP_REG_INFO
)
441 for (j
=0; j
< NUM_MACHINE_MODES
; ++j
)
442 INIT_REG_SET (&subregs_of_mode
[j
]);
447 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
449 /* The post-reload life analysis have (on a global basis) the same
450 registers live as was computed by reload itself. elimination
451 Otherwise offsets and such may be incorrect.
453 Reload will make some registers as live even though they do not
456 We don't want to create new auto-incs after reload, since they
457 are unlikely to be useful and can cause problems with shared
459 if (reload_completed
)
460 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
462 /* We want alias analysis information for local dead store elimination. */
463 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
464 init_alias_analysis ();
466 /* Always remove no-op moves. Do this before other processing so
467 that we don't have to keep re-scanning them. */
468 delete_noop_moves (f
);
470 /* Some targets can emit simpler epilogues if they know that sp was
471 not ever modified during the function. After reload, of course,
472 we've already emitted the epilogue so there's no sense searching. */
473 if (! reload_completed
)
474 notice_stack_pointer_modification (f
);
476 /* Allocate and zero out data structures that will record the
477 data from lifetime analysis. */
478 allocate_reg_life_data ();
479 allocate_bb_life_data ();
481 /* Find the set of registers live on function exit. */
482 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
484 /* "Update" life info from zero. It'd be nice to begin the
485 relaxation with just the exit and noreturn blocks, but that set
486 is not immediately handy. */
488 if (flags
& PROP_REG_INFO
)
489 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
490 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
493 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
494 end_alias_analysis ();
497 dump_flow_info (file
);
499 free_basic_block_vars (1);
501 /* Removing dead insns should've made jumptables really dead. */
502 delete_dead_jumptables ();
505 /* A subroutine of verify_wide_reg, called through for_each_rtx.
506 Search for REGNO. If found, return 2 if it is not wider than
510 verify_wide_reg_1 (px
, pregno
)
515 unsigned int regno
= *(int *) pregno
;
517 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
519 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
526 /* A subroutine of verify_local_live_at_start. Search through insns
527 of BB looking for register REGNO. */
530 verify_wide_reg (regno
, bb
)
534 rtx head
= bb
->head
, end
= bb
->end
;
540 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
548 head
= NEXT_INSN (head
);
553 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
554 dump_bb (bb
, rtl_dump_file
);
559 /* A subroutine of update_life_info. Verify that there are no untoward
560 changes in live_at_start during a local update. */
563 verify_local_live_at_start (new_live_at_start
, bb
)
564 regset new_live_at_start
;
567 if (reload_completed
)
569 /* After reload, there are no pseudos, nor subregs of multi-word
570 registers. The regsets should exactly match. */
571 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
575 fprintf (rtl_dump_file
,
576 "live_at_start mismatch in bb %d, aborting\nNew:\n",
578 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
579 fputs ("Old:\n", rtl_dump_file
);
580 dump_bb (bb
, rtl_dump_file
);
589 /* Find the set of changed registers. */
590 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
592 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
594 /* No registers should die. */
595 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
599 fprintf (rtl_dump_file
,
600 "Register %d died unexpectedly.\n", i
);
601 dump_bb (bb
, rtl_dump_file
);
606 /* Verify that the now-live register is wider than word_mode. */
607 verify_wide_reg (i
, bb
);
612 /* Updates life information starting with the basic blocks set in BLOCKS.
613 If BLOCKS is null, consider it to be the universal set.
615 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
616 we are only expecting local modifications to basic blocks. If we find
617 extra registers live at the beginning of a block, then we either killed
618 useful data, or we have a broken split that wants data not provided.
619 If we find registers removed from live_at_start, that means we have
620 a broken peephole that is killing a register it shouldn't.
622 ??? This is not true in one situation -- when a pre-reload splitter
623 generates subregs of a multi-word pseudo, current life analysis will
624 lose the kill. So we _can_ have a pseudo go live. How irritating.
626 Including PROP_REG_INFO does not properly refresh regs_ever_live
627 unless the caller resets it to zero. */
630 update_life_info (blocks
, extent
, prop_flags
)
632 enum update_life_extent extent
;
636 regset_head tmp_head
;
638 int stabilized_prop_flags
= prop_flags
;
641 tmp
= INITIALIZE_REG_SET (tmp_head
);
644 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
645 ? TV_LIFE_UPDATE
: TV_LIFE
);
647 /* Changes to the CFG are only allowed when
648 doing a global update for the entire CFG. */
649 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
650 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
653 /* For a global update, we go through the relaxation process again. */
654 if (extent
!= UPDATE_LIFE_LOCAL
)
660 calculate_global_regs_live (blocks
, blocks
,
661 prop_flags
& (PROP_SCAN_DEAD_CODE
662 | PROP_SCAN_DEAD_STORES
663 | PROP_ALLOW_CFG_CHANGES
));
665 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
666 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
669 /* Removing dead code may allow the CFG to be simplified which
670 in turn may allow for further dead code detection / removal. */
671 FOR_EACH_BB_REVERSE (bb
)
673 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
674 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
675 prop_flags
& (PROP_SCAN_DEAD_CODE
676 | PROP_SCAN_DEAD_STORES
677 | PROP_KILL_DEAD_CODE
));
680 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
681 subsequent propagate_block calls, since removing or acting as
682 removing dead code can affect global register liveness, which
683 is supposed to be finalized for this call after this loop. */
684 stabilized_prop_flags
685 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
686 | PROP_KILL_DEAD_CODE
);
691 /* We repeat regardless of what cleanup_cfg says. If there were
692 instructions deleted above, that might have been only a
693 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
694 Further improvement may be possible. */
695 cleanup_cfg (CLEANUP_EXPENSIVE
);
697 /* Zap the life information from the last round. If we don't
698 do this, we can wind up with registers that no longer appear
699 in the code being marked live at entry, which twiggs bogus
700 warnings from regno_uninitialized. */
703 CLEAR_REG_SET (bb
->global_live_at_start
);
704 CLEAR_REG_SET (bb
->global_live_at_end
);
708 /* If asked, remove notes from the blocks we'll update. */
709 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
710 count_or_remove_death_notes (blocks
, 1);
713 /* Clear log links in case we are asked to (re)compute them. */
714 if (prop_flags
& PROP_LOG_LINKS
)
715 clear_log_links (blocks
);
719 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
721 bb
= BASIC_BLOCK (i
);
723 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
724 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
726 if (extent
== UPDATE_LIFE_LOCAL
)
727 verify_local_live_at_start (tmp
, bb
);
732 FOR_EACH_BB_REVERSE (bb
)
734 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
736 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
738 if (extent
== UPDATE_LIFE_LOCAL
)
739 verify_local_live_at_start (tmp
, bb
);
745 if (prop_flags
& PROP_REG_INFO
)
747 /* The only pseudos that are live at the beginning of the function
748 are those that were not set anywhere in the function. local-alloc
749 doesn't know how to handle these correctly, so mark them as not
750 local to any one basic block. */
751 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
752 FIRST_PSEUDO_REGISTER
, i
,
753 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
755 /* We have a problem with any pseudoreg that lives across the setjmp.
756 ANSI says that if a user variable does not change in value between
757 the setjmp and the longjmp, then the longjmp preserves it. This
758 includes longjmp from a place where the pseudo appears dead.
759 (In principle, the value still exists if it is in scope.)
760 If the pseudo goes in a hard reg, some other value may occupy
761 that hard reg where this pseudo is dead, thus clobbering the pseudo.
762 Conclusion: such a pseudo must not go in a hard reg. */
763 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
764 FIRST_PSEUDO_REGISTER
, i
,
766 if (regno_reg_rtx
[i
] != 0)
768 REG_LIVE_LENGTH (i
) = -1;
769 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
773 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
774 ? TV_LIFE_UPDATE
: TV_LIFE
);
775 if (ndead
&& rtl_dump_file
)
776 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
780 /* Update life information in all blocks where BB_DIRTY is set. */
783 update_life_info_in_dirty_blocks (extent
, prop_flags
)
784 enum update_life_extent extent
;
787 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
792 sbitmap_zero (update_life_blocks
);
795 if (extent
== UPDATE_LIFE_LOCAL
)
797 if (bb
->flags
& BB_DIRTY
)
799 SET_BIT (update_life_blocks
, bb
->index
);
805 /* ??? Bootstrap with -march=pentium4 fails to terminate
806 with only a partial life update. */
807 SET_BIT (update_life_blocks
, bb
->index
);
808 if (bb
->flags
& BB_DIRTY
)
814 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
816 sbitmap_free (update_life_blocks
);
820 /* Free the variables allocated by find_basic_blocks.
822 KEEP_HEAD_END_P is nonzero if basic_block_info is not to be freed. */
825 free_basic_block_vars (keep_head_end_p
)
828 if (! keep_head_end_p
)
830 if (basic_block_info
)
833 VARRAY_FREE (basic_block_info
);
836 last_basic_block
= 0;
838 ENTRY_BLOCK_PTR
->aux
= NULL
;
839 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
840 EXIT_BLOCK_PTR
->aux
= NULL
;
841 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
845 /* Delete any insns that copy a register to itself. */
848 delete_noop_moves (f
)
849 rtx f ATTRIBUTE_UNUSED
;
857 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
859 next
= NEXT_INSN (insn
);
860 if (INSN_P (insn
) && noop_move_p (insn
))
864 /* If we're about to remove the first insn of a libcall
865 then move the libcall note to the next real insn and
866 update the retval note. */
867 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
868 && XEXP (note
, 0) != insn
)
870 rtx new_libcall_insn
= next_real_insn (insn
);
871 rtx retval_note
= find_reg_note (XEXP (note
, 0),
872 REG_RETVAL
, NULL_RTX
);
873 REG_NOTES (new_libcall_insn
)
874 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
875 REG_NOTES (new_libcall_insn
));
876 XEXP (retval_note
, 0) = new_libcall_insn
;
879 delete_insn_and_edges (insn
);
884 if (nnoops
&& rtl_dump_file
)
885 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
889 /* Delete any jump tables never referenced. We can't delete them at the
890 time of removing tablejump insn as they are referenced by the preceding
891 insns computing the destination, so we delay deleting and garbagecollect
892 them once life information is computed. */
894 delete_dead_jumptables ()
897 for (insn
= get_insns (); insn
; insn
= next
)
899 next
= NEXT_INSN (insn
);
900 if (GET_CODE (insn
) == CODE_LABEL
901 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
902 && GET_CODE (next
) == JUMP_INSN
903 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
904 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
907 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
908 delete_insn (NEXT_INSN (insn
));
910 next
= NEXT_INSN (next
);
915 /* Determine if the stack pointer is constant over the life of the function.
916 Only useful before prologues have been emitted. */
919 notice_stack_pointer_modification_1 (x
, pat
, data
)
921 rtx pat ATTRIBUTE_UNUSED
;
922 void *data ATTRIBUTE_UNUSED
;
924 if (x
== stack_pointer_rtx
925 /* The stack pointer is only modified indirectly as the result
926 of a push until later in flow. See the comments in rtl.texi
927 regarding Embedded Side-Effects on Addresses. */
928 || (GET_CODE (x
) == MEM
929 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
930 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
931 current_function_sp_is_unchanging
= 0;
935 notice_stack_pointer_modification (f
)
940 /* Assume that the stack pointer is unchanging if alloca hasn't
942 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
943 if (! current_function_sp_is_unchanging
)
946 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
950 /* Check if insn modifies the stack pointer. */
951 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
953 if (! current_function_sp_is_unchanging
)
959 /* Mark a register in SET. Hard registers in large modes get all
960 of their component registers set as well. */
967 regset set
= (regset
) xset
;
968 int regno
= REGNO (reg
);
970 if (GET_MODE (reg
) == BLKmode
)
973 SET_REGNO_REG_SET (set
, regno
);
974 if (regno
< FIRST_PSEUDO_REGISTER
)
976 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
978 SET_REGNO_REG_SET (set
, regno
+ n
);
982 /* Mark those regs which are needed at the end of the function as live
983 at the end of the last basic block. */
986 mark_regs_live_at_end (set
)
991 /* If exiting needs the right stack value, consider the stack pointer
992 live at the end of the function. */
993 if ((HAVE_epilogue
&& reload_completed
)
994 || ! EXIT_IGNORE_STACK
995 || (! FRAME_POINTER_REQUIRED
996 && ! current_function_calls_alloca
997 && flag_omit_frame_pointer
)
998 || current_function_sp_is_unchanging
)
1000 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
1003 /* Mark the frame pointer if needed at the end of the function. If
1004 we end up eliminating it, it will be removed from the live list
1005 of each basic block by reload. */
1007 if (! reload_completed
|| frame_pointer_needed
)
1009 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
1010 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1011 /* If they are different, also mark the hard frame pointer as live. */
1012 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
1013 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
1017 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
1018 /* Many architectures have a GP register even without flag_pic.
1019 Assume the pic register is not in use, or will be handled by
1020 other means, if it is not fixed. */
1021 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1022 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1023 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1026 /* Mark all global registers, and all registers used by the epilogue
1027 as being live at the end of the function since they may be
1028 referenced by our caller. */
1029 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1030 if (global_regs
[i
] || EPILOGUE_USES (i
))
1031 SET_REGNO_REG_SET (set
, i
);
1033 if (HAVE_epilogue
&& reload_completed
)
1035 /* Mark all call-saved registers that we actually used. */
1036 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1037 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1038 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1039 SET_REGNO_REG_SET (set
, i
);
1042 #ifdef EH_RETURN_DATA_REGNO
1043 /* Mark the registers that will contain data for the handler. */
1044 if (reload_completed
&& current_function_calls_eh_return
)
1047 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1048 if (regno
== INVALID_REGNUM
)
1050 SET_REGNO_REG_SET (set
, regno
);
1053 #ifdef EH_RETURN_STACKADJ_RTX
1054 if ((! HAVE_epilogue
|| ! reload_completed
)
1055 && current_function_calls_eh_return
)
1057 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1058 if (tmp
&& REG_P (tmp
))
1059 mark_reg (tmp
, set
);
1062 #ifdef EH_RETURN_HANDLER_RTX
1063 if ((! HAVE_epilogue
|| ! reload_completed
)
1064 && current_function_calls_eh_return
)
1066 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1067 if (tmp
&& REG_P (tmp
))
1068 mark_reg (tmp
, set
);
1072 /* Mark function return value. */
1073 diddle_return_value (mark_reg
, set
);
1076 /* Callback function for for_each_successor_phi. DATA is a regset.
1077 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1078 INSN, in the regset. */
1081 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1082 rtx insn ATTRIBUTE_UNUSED
;
1083 int dest_regno ATTRIBUTE_UNUSED
;
1087 regset live
= (regset
) data
;
1088 SET_REGNO_REG_SET (live
, src_regno
);
1092 /* Propagate global life info around the graph of basic blocks. Begin
1093 considering blocks with their corresponding bit set in BLOCKS_IN.
1094 If BLOCKS_IN is null, consider it the universal set.
1096 BLOCKS_OUT is set for every block that was changed. */
1099 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1100 sbitmap blocks_in
, blocks_out
;
1103 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1104 regset tmp
, new_live_at_end
, invalidated_by_call
;
1105 regset_head tmp_head
, invalidated_by_call_head
;
1106 regset_head new_live_at_end_head
;
1109 /* Some passes used to forget clear aux field of basic block causing
1110 sick behavior here. */
1111 #ifdef ENABLE_CHECKING
1112 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1117 tmp
= INITIALIZE_REG_SET (tmp_head
);
1118 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1119 invalidated_by_call
= INITIALIZE_REG_SET (invalidated_by_call_head
);
1121 /* Inconveniently, this is only readily available in hard reg set form. */
1122 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1123 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1124 SET_REGNO_REG_SET (invalidated_by_call
, i
);
1126 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1127 because the `head == tail' style test for an empty queue doesn't
1128 work with a full queue. */
1129 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1131 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1133 /* Queue the blocks set in the initial mask. Do this in reverse block
1134 number order so that we are more likely for the first round to do
1135 useful work. We use AUX non-null to flag that the block is queued. */
1139 if (TEST_BIT (blocks_in
, bb
->index
))
1154 /* We clean aux when we remove the initially-enqueued bbs, but we
1155 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1157 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1160 sbitmap_zero (blocks_out
);
1162 /* We work through the queue until there are no more blocks. What
1163 is live at the end of this block is precisely the union of what
1164 is live at the beginning of all its successors. So, we set its
1165 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1166 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1167 this block by walking through the instructions in this block in
1168 reverse order and updating as we go. If that changed
1169 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1170 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1172 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1173 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1174 must either be live at the end of the block, or used within the
1175 block. In the latter case, it will certainly never disappear
1176 from GLOBAL_LIVE_AT_START. In the former case, the register
1177 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1178 for one of the successor blocks. By induction, that cannot
1180 while (qhead
!= qtail
)
1182 int rescan
, changed
;
1191 /* Begin by propagating live_at_start from the successor blocks. */
1192 CLEAR_REG_SET (new_live_at_end
);
1195 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1197 basic_block sb
= e
->dest
;
1199 /* Call-clobbered registers die across exception and
1201 /* ??? Abnormal call edges ignored for the moment, as this gets
1202 confused by sibling call edges, which crashes reg-stack. */
1203 if (e
->flags
& EDGE_EH
)
1205 bitmap_operation (tmp
, sb
->global_live_at_start
,
1206 invalidated_by_call
, BITMAP_AND_COMPL
);
1207 IOR_REG_SET (new_live_at_end
, tmp
);
1210 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1212 /* If a target saves one register in another (instead of on
1213 the stack) the save register will need to be live for EH. */
1214 if (e
->flags
& EDGE_EH
)
1215 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1217 SET_REGNO_REG_SET (new_live_at_end
, i
);
1221 /* This might be a noreturn function that throws. And
1222 even if it isn't, getting the unwind info right helps
1224 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1226 SET_REGNO_REG_SET (new_live_at_end
, i
);
1229 /* The all-important stack pointer must always be live. */
1230 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1232 /* Before reload, there are a few registers that must be forced
1233 live everywhere -- which might not already be the case for
1234 blocks within infinite loops. */
1235 if (! reload_completed
)
1237 /* Any reference to any pseudo before reload is a potential
1238 reference of the frame pointer. */
1239 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1241 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1242 /* Pseudos with argument area equivalences may require
1243 reloading via the argument pointer. */
1244 if (fixed_regs
[ARG_POINTER_REGNUM
])
1245 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1248 /* Any constant, or pseudo with constant equivalences, may
1249 require reloading from memory using the pic register. */
1250 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1251 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1252 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1255 /* Regs used in phi nodes are not included in
1256 global_live_at_start, since they are live only along a
1257 particular edge. Set those regs that are live because of a
1258 phi node alternative corresponding to this particular block. */
1260 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1263 if (bb
== ENTRY_BLOCK_PTR
)
1265 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1269 /* On our first pass through this block, we'll go ahead and continue.
1270 Recognize first pass by local_set NULL. On subsequent passes, we
1271 get to skip out early if live_at_end wouldn't have changed. */
1273 if (bb
->local_set
== NULL
)
1275 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1276 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1281 /* If any bits were removed from live_at_end, we'll have to
1282 rescan the block. This wouldn't be necessary if we had
1283 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1284 local_live is really dependent on live_at_end. */
1285 CLEAR_REG_SET (tmp
);
1286 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1287 new_live_at_end
, BITMAP_AND_COMPL
);
1291 /* If any of the registers in the new live_at_end set are
1292 conditionally set in this basic block, we must rescan.
1293 This is because conditional lifetimes at the end of the
1294 block do not just take the live_at_end set into account,
1295 but also the liveness at the start of each successor
1296 block. We can miss changes in those sets if we only
1297 compare the new live_at_end against the previous one. */
1298 CLEAR_REG_SET (tmp
);
1299 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1300 bb
->cond_local_set
, BITMAP_AND
);
1305 /* Find the set of changed bits. Take this opportunity
1306 to notice that this set is empty and early out. */
1307 CLEAR_REG_SET (tmp
);
1308 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1309 new_live_at_end
, BITMAP_XOR
);
1313 /* If any of the changed bits overlap with local_set,
1314 we'll have to rescan the block. Detect overlap by
1315 the AND with ~local_set turning off bits. */
1316 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1321 /* Let our caller know that BB changed enough to require its
1322 death notes updated. */
1324 SET_BIT (blocks_out
, bb
->index
);
1328 /* Add to live_at_start the set of all registers in
1329 new_live_at_end that aren't in the old live_at_end. */
1331 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1333 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1335 changed
= bitmap_operation (bb
->global_live_at_start
,
1336 bb
->global_live_at_start
,
1343 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1345 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1346 into live_at_start. */
1347 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1348 bb
->cond_local_set
, flags
);
1350 /* If live_at start didn't change, no need to go farther. */
1351 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1354 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1357 /* Queue all predecessors of BB so that we may re-examine
1358 their live_at_end. */
1359 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1361 basic_block pb
= e
->src
;
1362 if (pb
->aux
== NULL
)
1373 FREE_REG_SET (new_live_at_end
);
1374 FREE_REG_SET (invalidated_by_call
);
1378 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1380 basic_block bb
= BASIC_BLOCK (i
);
1381 FREE_REG_SET (bb
->local_set
);
1382 FREE_REG_SET (bb
->cond_local_set
);
1389 FREE_REG_SET (bb
->local_set
);
1390 FREE_REG_SET (bb
->cond_local_set
);
1398 /* This structure is used to pass parameters to and from the
1399 the function find_regno_partial(). It is used to pass in the
1400 register number we are looking, as well as to return any rtx
1404 unsigned regno_to_find
;
1406 } find_regno_partial_param
;
1409 /* Find the rtx for the reg numbers specified in 'data' if it is
1410 part of an expression which only uses part of the register. Return
1411 it in the structure passed in. */
1413 find_regno_partial (ptr
, data
)
1417 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1418 unsigned reg
= param
->regno_to_find
;
1419 param
->retval
= NULL_RTX
;
1421 if (*ptr
== NULL_RTX
)
1424 switch (GET_CODE (*ptr
))
1428 case STRICT_LOW_PART
:
1429 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1431 param
->retval
= XEXP (*ptr
, 0);
1437 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1438 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1440 param
->retval
= SUBREG_REG (*ptr
);
1452 /* Process all immediate successors of the entry block looking for pseudo
1453 registers which are live on entry. Find all of those whose first
1454 instance is a partial register reference of some kind, and initialize
1455 them to 0 after the entry block. This will prevent bit sets within
1456 registers whose value is unknown, and may contain some kind of sticky
1457 bits we don't want. */
1460 initialize_uninitialized_subregs ()
1464 int reg
, did_something
= 0;
1465 find_regno_partial_param param
;
1467 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1469 basic_block bb
= e
->dest
;
1470 regset map
= bb
->global_live_at_start
;
1471 EXECUTE_IF_SET_IN_REG_SET (map
,
1472 FIRST_PSEUDO_REGISTER
, reg
,
1474 int uid
= REGNO_FIRST_UID (reg
);
1477 /* Find an insn which mentions the register we are looking for.
1478 Its preferable to have an instance of the register's rtl since
1479 there may be various flags set which we need to duplicate.
1480 If we can't find it, its probably an automatic whose initial
1481 value doesn't matter, or hopefully something we don't care about. */
1482 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1486 /* Found the insn, now get the REG rtx, if we can. */
1487 param
.regno_to_find
= reg
;
1488 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1489 if (param
.retval
!= NULL_RTX
)
1491 insn
= gen_move_insn (param
.retval
,
1492 CONST0_RTX (GET_MODE (param
.retval
)));
1493 insert_insn_on_edge (insn
, e
);
1501 commit_edge_insertions ();
1502 return did_something
;
1506 /* Subroutines of life analysis. */
1508 /* Allocate the permanent data structures that represent the results
1509 of life analysis. Not static since used also for stupid life analysis. */
1512 allocate_bb_life_data ()
1516 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1518 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1519 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1522 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1526 allocate_reg_life_data ()
1530 max_regno
= max_reg_num ();
1532 /* Recalculate the register space, in case it has grown. Old style
1533 vector oriented regsets would set regset_{size,bytes} here also. */
1534 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1536 /* Reset all the data we'll collect in propagate_block and its
1538 for (i
= 0; i
< max_regno
; i
++)
1542 REG_N_DEATHS (i
) = 0;
1543 REG_N_CALLS_CROSSED (i
) = 0;
1544 REG_LIVE_LENGTH (i
) = 0;
1546 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1550 /* Delete dead instructions for propagate_block. */
1553 propagate_block_delete_insn (insn
)
1556 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1558 /* If the insn referred to a label, and that label was attached to
1559 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1560 pretty much mandatory to delete it, because the ADDR_VEC may be
1561 referencing labels that no longer exist.
1563 INSN may reference a deleted label, particularly when a jump
1564 table has been optimized into a direct jump. There's no
1565 real good way to fix up the reference to the deleted label
1566 when the label is deleted, so we just allow it here. */
1568 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1570 rtx label
= XEXP (inote
, 0);
1573 /* The label may be forced if it has been put in the constant
1574 pool. If that is the only use we must discard the table
1575 jump following it, but not the label itself. */
1576 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1577 && (next
= next_nonnote_insn (label
)) != NULL
1578 && GET_CODE (next
) == JUMP_INSN
1579 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1580 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1582 rtx pat
= PATTERN (next
);
1583 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1584 int len
= XVECLEN (pat
, diff_vec_p
);
1587 for (i
= 0; i
< len
; i
++)
1588 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1590 delete_insn_and_edges (next
);
1595 delete_insn_and_edges (insn
);
1599 /* Delete dead libcalls for propagate_block. Return the insn
1600 before the libcall. */
1603 propagate_block_delete_libcall ( insn
, note
)
1606 rtx first
= XEXP (note
, 0);
1607 rtx before
= PREV_INSN (first
);
1609 delete_insn_chain_and_edges (first
, insn
);
1614 /* Update the life-status of regs for one insn. Return the previous insn. */
1617 propagate_one_insn (pbi
, insn
)
1618 struct propagate_block_info
*pbi
;
1621 rtx prev
= PREV_INSN (insn
);
1622 int flags
= pbi
->flags
;
1623 int insn_is_dead
= 0;
1624 int libcall_is_dead
= 0;
1628 if (! INSN_P (insn
))
1631 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1632 if (flags
& PROP_SCAN_DEAD_CODE
)
1634 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1635 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1636 && libcall_dead_p (pbi
, note
, insn
));
1639 /* If an instruction consists of just dead store(s) on final pass,
1641 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1643 /* If we're trying to delete a prologue or epilogue instruction
1644 that isn't flagged as possibly being dead, something is wrong.
1645 But if we are keeping the stack pointer depressed, we might well
1646 be deleting insns that are used to compute the amount to update
1647 it by, so they are fine. */
1648 if (reload_completed
1649 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1650 && (TYPE_RETURNS_STACK_DEPRESSED
1651 (TREE_TYPE (current_function_decl
))))
1652 && (((HAVE_epilogue
|| HAVE_prologue
)
1653 && prologue_epilogue_contains (insn
))
1654 || (HAVE_sibcall_epilogue
1655 && sibcall_epilogue_contains (insn
)))
1656 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1657 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1659 /* Record sets. Do this even for dead instructions, since they
1660 would have killed the values if they hadn't been deleted. */
1661 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1663 /* CC0 is now known to be dead. Either this insn used it,
1664 in which case it doesn't anymore, or clobbered it,
1665 so the next insn can't use it. */
1668 if (libcall_is_dead
)
1669 prev
= propagate_block_delete_libcall ( insn
, note
);
1673 /* If INSN contains a RETVAL note and is dead, but the libcall
1674 as a whole is not dead, then we want to remove INSN, but
1675 not the whole libcall sequence.
1677 However, we need to also remove the dangling REG_LIBCALL
1678 note so that we do not have mis-matched LIBCALL/RETVAL
1679 notes. In theory we could find a new location for the
1680 REG_RETVAL note, but it hardly seems worth the effort.
1682 NOTE at this point will be the RETVAL note if it exists. */
1688 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1689 remove_note (XEXP (note
, 0), libcall_note
);
1692 /* Similarly if INSN contains a LIBCALL note, remove the
1693 dangling REG_RETVAL note. */
1694 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
1700 = find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
1701 remove_note (XEXP (note
, 0), retval_note
);
1704 /* Now delete INSN. */
1705 propagate_block_delete_insn (insn
);
1711 /* See if this is an increment or decrement that can be merged into
1712 a following memory address. */
1715 rtx x
= single_set (insn
);
1717 /* Does this instruction increment or decrement a register? */
1718 if ((flags
& PROP_AUTOINC
)
1720 && GET_CODE (SET_DEST (x
)) == REG
1721 && (GET_CODE (SET_SRC (x
)) == PLUS
1722 || GET_CODE (SET_SRC (x
)) == MINUS
)
1723 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1724 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1725 /* Ok, look for a following memory ref we can combine with.
1726 If one is found, change the memory ref to a PRE_INC
1727 or PRE_DEC, cancel this insn, and return 1.
1728 Return 0 if nothing has been done. */
1729 && try_pre_increment_1 (pbi
, insn
))
1732 #endif /* AUTO_INC_DEC */
1734 CLEAR_REG_SET (pbi
->new_set
);
1736 /* If this is not the final pass, and this insn is copying the value of
1737 a library call and it's dead, don't scan the insns that perform the
1738 library call, so that the call's arguments are not marked live. */
1739 if (libcall_is_dead
)
1741 /* Record the death of the dest reg. */
1742 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1744 insn
= XEXP (note
, 0);
1745 return PREV_INSN (insn
);
1747 else if (GET_CODE (PATTERN (insn
)) == SET
1748 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1749 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1750 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1751 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1752 /* We have an insn to pop a constant amount off the stack.
1753 (Such insns use PLUS regardless of the direction of the stack,
1754 and any insn to adjust the stack by a constant is always a pop.)
1755 These insns, if not dead stores, have no effect on life, though
1756 they do have an effect on the memory stores we are tracking. */
1757 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1761 /* Any regs live at the time of a call instruction must not go
1762 in a register clobbered by calls. Find all regs now live and
1763 record this for them. */
1765 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1766 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1767 { REG_N_CALLS_CROSSED (i
)++; });
1769 /* Record sets. Do this even for dead instructions, since they
1770 would have killed the values if they hadn't been deleted. */
1771 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1773 if (GET_CODE (insn
) == CALL_INSN
)
1779 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1780 cond
= COND_EXEC_TEST (PATTERN (insn
));
1782 /* Non-constant calls clobber memory, constant calls do not
1783 clobber memory, though they may clobber outgoing arguments
1785 if (! CONST_OR_PURE_CALL_P (insn
))
1787 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1788 pbi
->mem_set_list_len
= 0;
1791 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1793 /* There may be extra registers to be clobbered. */
1794 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1796 note
= XEXP (note
, 1))
1797 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1798 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1799 cond
, insn
, pbi
->flags
);
1801 /* Calls change all call-used and global registers. */
1802 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1803 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1805 /* We do not want REG_UNUSED notes for these registers. */
1806 mark_set_1 (pbi
, CLOBBER
, regno_reg_rtx
[i
], cond
, insn
,
1807 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1811 /* If an insn doesn't use CC0, it becomes dead since we assume
1812 that every insn clobbers it. So show it dead here;
1813 mark_used_regs will set it live if it is referenced. */
1818 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1819 if ((flags
& PROP_EQUAL_NOTES
)
1820 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1821 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1822 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1824 /* Sometimes we may have inserted something before INSN (such as a move)
1825 when we make an auto-inc. So ensure we will scan those insns. */
1827 prev
= PREV_INSN (insn
);
1830 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1836 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1837 cond
= COND_EXEC_TEST (PATTERN (insn
));
1839 /* Calls use their arguments. */
1840 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1842 note
= XEXP (note
, 1))
1843 if (GET_CODE (XEXP (note
, 0)) == USE
)
1844 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1847 /* The stack ptr is used (honorarily) by a CALL insn. */
1848 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1850 /* Calls may also reference any of the global registers,
1851 so they are made live. */
1852 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1854 mark_used_reg (pbi
, regno_reg_rtx
[i
], cond
, insn
);
1858 /* On final pass, update counts of how many insns in which each reg
1860 if (flags
& PROP_REG_INFO
)
1861 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1862 { REG_LIVE_LENGTH (i
)++; });
1867 /* Initialize a propagate_block_info struct for public consumption.
1868 Note that the structure itself is opaque to this file, but that
1869 the user can use the regsets provided here. */
1871 struct propagate_block_info
*
1872 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1874 regset live
, local_set
, cond_local_set
;
1877 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1880 pbi
->reg_live
= live
;
1881 pbi
->mem_set_list
= NULL_RTX
;
1882 pbi
->mem_set_list_len
= 0;
1883 pbi
->local_set
= local_set
;
1884 pbi
->cond_local_set
= cond_local_set
;
1888 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1889 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1891 pbi
->reg_next_use
= NULL
;
1893 pbi
->new_set
= BITMAP_XMALLOC ();
1895 #ifdef HAVE_conditional_execution
1896 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1897 free_reg_cond_life_info
);
1898 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1900 /* If this block ends in a conditional branch, for each register live
1901 from one side of the branch and not the other, record the register
1902 as conditionally dead. */
1903 if (GET_CODE (bb
->end
) == JUMP_INSN
1904 && any_condjump_p (bb
->end
))
1906 regset_head diff_head
;
1907 regset diff
= INITIALIZE_REG_SET (diff_head
);
1908 basic_block bb_true
, bb_false
;
1909 rtx cond_true
, cond_false
, set_src
;
1912 /* Identify the successor blocks. */
1913 bb_true
= bb
->succ
->dest
;
1914 if (bb
->succ
->succ_next
!= NULL
)
1916 bb_false
= bb
->succ
->succ_next
->dest
;
1918 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1920 basic_block t
= bb_false
;
1924 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1929 /* This can happen with a conditional jump to the next insn. */
1930 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1933 /* Simplest way to do nothing. */
1937 /* Extract the condition from the branch. */
1938 set_src
= SET_SRC (pc_set (bb
->end
));
1939 cond_true
= XEXP (set_src
, 0);
1940 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1941 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1942 XEXP (cond_true
, 1));
1943 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1946 cond_false
= cond_true
;
1950 /* Compute which register lead different lives in the successors. */
1951 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1952 bb_false
->global_live_at_start
, BITMAP_XOR
))
1954 rtx reg
= XEXP (cond_true
, 0);
1956 if (GET_CODE (reg
) == SUBREG
)
1957 reg
= SUBREG_REG (reg
);
1959 if (GET_CODE (reg
) != REG
)
1962 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1964 /* For each such register, mark it conditionally dead. */
1965 EXECUTE_IF_SET_IN_REG_SET
1968 struct reg_cond_life_info
*rcli
;
1971 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1973 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1977 rcli
->condition
= cond
;
1978 rcli
->stores
= const0_rtx
;
1979 rcli
->orig_condition
= cond
;
1981 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1982 (splay_tree_value
) rcli
);
1986 FREE_REG_SET (diff
);
1990 /* If this block has no successors, any stores to the frame that aren't
1991 used later in the block are dead. So make a pass over the block
1992 recording any such that are made and show them dead at the end. We do
1993 a very conservative and simple job here. */
1995 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1996 && (TYPE_RETURNS_STACK_DEPRESSED
1997 (TREE_TYPE (current_function_decl
))))
1998 && (flags
& PROP_SCAN_DEAD_STORES
)
1999 && (bb
->succ
== NULL
2000 || (bb
->succ
->succ_next
== NULL
2001 && bb
->succ
->dest
== EXIT_BLOCK_PTR
2002 && ! current_function_calls_eh_return
)))
2005 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
2006 if (GET_CODE (insn
) == INSN
2007 && (set
= single_set (insn
))
2008 && GET_CODE (SET_DEST (set
)) == MEM
)
2010 rtx mem
= SET_DEST (set
);
2011 rtx canon_mem
= canon_rtx (mem
);
2013 /* This optimization is performed by faking a store to the
2014 memory at the end of the block. This doesn't work for
2015 unchanging memories because multiple stores to unchanging
2016 memory is illegal and alias analysis doesn't consider it. */
2017 if (RTX_UNCHANGING_P (canon_mem
))
2020 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
2021 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
2022 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
2023 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
2024 add_to_mem_set_list (pbi
, canon_mem
);
2031 /* Release a propagate_block_info struct. */
2034 free_propagate_block_info (pbi
)
2035 struct propagate_block_info
*pbi
;
2037 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2039 BITMAP_XFREE (pbi
->new_set
);
2041 #ifdef HAVE_conditional_execution
2042 splay_tree_delete (pbi
->reg_cond_dead
);
2043 BITMAP_XFREE (pbi
->reg_cond_reg
);
2046 if (pbi
->reg_next_use
)
2047 free (pbi
->reg_next_use
);
2052 /* Compute the registers live at the beginning of a basic block BB from
2053 those live at the end.
2055 When called, REG_LIVE contains those live at the end. On return, it
2056 contains those live at the beginning.
2058 LOCAL_SET, if non-null, will be set with all registers killed
2059 unconditionally by this basic block.
2060 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2061 killed conditionally by this basic block. If there is any unconditional
2062 set of a register, then the corresponding bit will be set in LOCAL_SET
2063 and cleared in COND_LOCAL_SET.
2064 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2065 case, the resulting set will be equal to the union of the two sets that
2066 would otherwise be computed.
2068 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2071 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2075 regset cond_local_set
;
2078 struct propagate_block_info
*pbi
;
2082 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2084 if (flags
& PROP_REG_INFO
)
2088 /* Process the regs live at the end of the block.
2089 Mark them as not local to any one basic block. */
2090 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2091 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2094 /* Scan the block an insn at a time from end to beginning. */
2097 for (insn
= bb
->end
;; insn
= prev
)
2099 /* If this is a call to `setjmp' et al, warn if any
2100 non-volatile datum is live. */
2101 if ((flags
& PROP_REG_INFO
)
2102 && GET_CODE (insn
) == CALL_INSN
2103 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2104 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2106 prev
= propagate_one_insn (pbi
, insn
);
2107 changed
|= NEXT_INSN (prev
) != insn
;
2109 if (insn
== bb
->head
)
2113 free_propagate_block_info (pbi
);
2118 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2119 (SET expressions whose destinations are registers dead after the insn).
2120 NEEDED is the regset that says which regs are alive after the insn.
2122 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2124 If X is the entire body of an insn, NOTES contains the reg notes
2125 pertaining to the insn. */
2128 insn_dead_p (pbi
, x
, call_ok
, notes
)
2129 struct propagate_block_info
*pbi
;
2132 rtx notes ATTRIBUTE_UNUSED
;
2134 enum rtx_code code
= GET_CODE (x
);
2136 /* Don't eliminate insns that may trap. */
2137 if (flag_non_call_exceptions
&& may_trap_p (x
))
2141 /* As flow is invoked after combine, we must take existing AUTO_INC
2142 expressions into account. */
2143 for (; notes
; notes
= XEXP (notes
, 1))
2145 if (REG_NOTE_KIND (notes
) == REG_INC
)
2147 int regno
= REGNO (XEXP (notes
, 0));
2149 /* Don't delete insns to set global regs. */
2150 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2151 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2157 /* If setting something that's a reg or part of one,
2158 see if that register's altered value will be live. */
2162 rtx r
= SET_DEST (x
);
2165 if (GET_CODE (r
) == CC0
)
2166 return ! pbi
->cc0_live
;
2169 /* A SET that is a subroutine call cannot be dead. */
2170 if (GET_CODE (SET_SRC (x
)) == CALL
)
2176 /* Don't eliminate loads from volatile memory or volatile asms. */
2177 else if (volatile_refs_p (SET_SRC (x
)))
2180 if (GET_CODE (r
) == MEM
)
2184 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2187 canon_r
= canon_rtx (r
);
2189 /* Walk the set of memory locations we are currently tracking
2190 and see if one is an identical match to this memory location.
2191 If so, this memory write is dead (remember, we're walking
2192 backwards from the end of the block to the start). Since
2193 rtx_equal_p does not check the alias set or flags, we also
2194 must have the potential for them to conflict (anti_dependence). */
2195 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2196 if (anti_dependence (r
, XEXP (temp
, 0)))
2198 rtx mem
= XEXP (temp
, 0);
2200 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2201 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2202 <= GET_MODE_SIZE (GET_MODE (mem
))))
2206 /* Check if memory reference matches an auto increment. Only
2207 post increment/decrement or modify are valid. */
2208 if (GET_MODE (mem
) == GET_MODE (r
)
2209 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2210 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2211 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2212 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2213 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2220 while (GET_CODE (r
) == SUBREG
2221 || GET_CODE (r
) == STRICT_LOW_PART
2222 || GET_CODE (r
) == ZERO_EXTRACT
)
2225 if (GET_CODE (r
) == REG
)
2227 int regno
= REGNO (r
);
2230 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2233 /* If this is a hard register, verify that subsequent
2234 words are not needed. */
2235 if (regno
< FIRST_PSEUDO_REGISTER
)
2237 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2240 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2244 /* Don't delete insns to set global regs. */
2245 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2248 /* Make sure insns to set the stack pointer aren't deleted. */
2249 if (regno
== STACK_POINTER_REGNUM
)
2252 /* ??? These bits might be redundant with the force live bits
2253 in calculate_global_regs_live. We would delete from
2254 sequential sets; whether this actually affects real code
2255 for anything but the stack pointer I don't know. */
2256 /* Make sure insns to set the frame pointer aren't deleted. */
2257 if (regno
== FRAME_POINTER_REGNUM
2258 && (! reload_completed
|| frame_pointer_needed
))
2260 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2261 if (regno
== HARD_FRAME_POINTER_REGNUM
2262 && (! reload_completed
|| frame_pointer_needed
))
2266 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2267 /* Make sure insns to set arg pointer are never deleted
2268 (if the arg pointer isn't fixed, there will be a USE
2269 for it, so we can treat it normally). */
2270 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2274 /* Otherwise, the set is dead. */
2280 /* If performing several activities, insn is dead if each activity
2281 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2282 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2284 else if (code
== PARALLEL
)
2286 int i
= XVECLEN (x
, 0);
2288 for (i
--; i
>= 0; i
--)
2289 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2290 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2291 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2297 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2298 is not necessarily true for hard registers. */
2299 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2300 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2301 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2304 /* We do not check other CLOBBER or USE here. An insn consisting of just
2305 a CLOBBER or just a USE should not be deleted. */
2309 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2310 return 1 if the entire library call is dead.
2311 This is true if INSN copies a register (hard or pseudo)
2312 and if the hard return reg of the call insn is dead.
2313 (The caller should have tested the destination of the SET inside
2314 INSN already for death.)
2316 If this insn doesn't just copy a register, then we don't
2317 have an ordinary libcall. In that case, cse could not have
2318 managed to substitute the source for the dest later on,
2319 so we can assume the libcall is dead.
2321 PBI is the block info giving pseudoregs live before this insn.
2322 NOTE is the REG_RETVAL note of the insn. */
2325 libcall_dead_p (pbi
, note
, insn
)
2326 struct propagate_block_info
*pbi
;
2330 rtx x
= single_set (insn
);
2334 rtx r
= SET_SRC (x
);
2336 if (GET_CODE (r
) == REG
)
2338 rtx call
= XEXP (note
, 0);
2342 /* Find the call insn. */
2343 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2344 call
= NEXT_INSN (call
);
2346 /* If there is none, do nothing special,
2347 since ordinary death handling can understand these insns. */
2351 /* See if the hard reg holding the value is dead.
2352 If this is a PARALLEL, find the call within it. */
2353 call_pat
= PATTERN (call
);
2354 if (GET_CODE (call_pat
) == PARALLEL
)
2356 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2357 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2358 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2361 /* This may be a library call that is returning a value
2362 via invisible pointer. Do nothing special, since
2363 ordinary death handling can understand these insns. */
2367 call_pat
= XVECEXP (call_pat
, 0, i
);
2370 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2376 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2377 live at function entry. Don't count global register variables, variables
2378 in registers that can be used for function arg passing, or variables in
2379 fixed hard registers. */
2382 regno_uninitialized (regno
)
2385 if (n_basic_blocks
== 0
2386 || (regno
< FIRST_PSEUDO_REGISTER
2387 && (global_regs
[regno
]
2388 || fixed_regs
[regno
]
2389 || FUNCTION_ARG_REGNO_P (regno
))))
2392 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->global_live_at_end
, regno
);
2395 /* 1 if register REGNO was alive at a place where `setjmp' was called
2396 and was set more than once or is an argument.
2397 Such regs may be clobbered by `longjmp'. */
2400 regno_clobbered_at_setjmp (regno
)
2403 if (n_basic_blocks
== 0)
2406 return ((REG_N_SETS (regno
) > 1
2407 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->global_live_at_end
, regno
))
2408 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2411 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2412 maximal list size; look for overlaps in mode and select the largest. */
2414 add_to_mem_set_list (pbi
, mem
)
2415 struct propagate_block_info
*pbi
;
2420 /* We don't know how large a BLKmode store is, so we must not
2421 take them into consideration. */
2422 if (GET_MODE (mem
) == BLKmode
)
2425 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2427 rtx e
= XEXP (i
, 0);
2428 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2430 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2433 /* If we must store a copy of the mem, we can just modify
2434 the mode of the stored copy. */
2435 if (pbi
->flags
& PROP_AUTOINC
)
2436 PUT_MODE (e
, GET_MODE (mem
));
2445 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2448 /* Store a copy of mem, otherwise the address may be
2449 scrogged by find_auto_inc. */
2450 if (pbi
->flags
& PROP_AUTOINC
)
2451 mem
= shallow_copy_rtx (mem
);
2453 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2454 pbi
->mem_set_list_len
++;
2458 /* INSN references memory, possibly using autoincrement addressing modes.
2459 Find any entries on the mem_set_list that need to be invalidated due
2460 to an address change. */
2463 invalidate_mems_from_autoinc (px
, data
)
2468 struct propagate_block_info
*pbi
= data
;
2470 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2472 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2479 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2482 invalidate_mems_from_set (pbi
, exp
)
2483 struct propagate_block_info
*pbi
;
2486 rtx temp
= pbi
->mem_set_list
;
2487 rtx prev
= NULL_RTX
;
2492 next
= XEXP (temp
, 1);
2493 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2495 /* Splice this entry out of the list. */
2497 XEXP (prev
, 1) = next
;
2499 pbi
->mem_set_list
= next
;
2500 free_EXPR_LIST_node (temp
);
2501 pbi
->mem_set_list_len
--;
2509 /* Process the registers that are set within X. Their bits are set to
2510 1 in the regset DEAD, because they are dead prior to this insn.
2512 If INSN is nonzero, it is the insn being processed.
2514 FLAGS is the set of operations to perform. */
2517 mark_set_regs (pbi
, x
, insn
)
2518 struct propagate_block_info
*pbi
;
2521 rtx cond
= NULL_RTX
;
2526 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2528 if (REG_NOTE_KIND (link
) == REG_INC
)
2529 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2530 (GET_CODE (x
) == COND_EXEC
2531 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2535 switch (code
= GET_CODE (x
))
2539 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2543 cond
= COND_EXEC_TEST (x
);
2544 x
= COND_EXEC_CODE (x
);
2551 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2553 rtx sub
= XVECEXP (x
, 0, i
);
2554 switch (code
= GET_CODE (sub
))
2557 if (cond
!= NULL_RTX
)
2560 cond
= COND_EXEC_TEST (sub
);
2561 sub
= COND_EXEC_CODE (sub
);
2562 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2568 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2583 /* Process a single set, which appears in INSN. REG (which may not
2584 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2585 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2586 If the set is conditional (because it appear in a COND_EXEC), COND
2587 will be the condition. */
2590 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2591 struct propagate_block_info
*pbi
;
2593 rtx reg
, cond
, insn
;
2596 int regno_first
= -1, regno_last
= -1;
2597 unsigned long not_dead
= 0;
2600 /* Modifying just one hardware register of a multi-reg value or just a
2601 byte field of a register does not mean the value from before this insn
2602 is now dead. Of course, if it was dead after it's unused now. */
2604 switch (GET_CODE (reg
))
2607 /* Some targets place small structures in registers for return values of
2608 functions. We have to detect this case specially here to get correct
2609 flow information. */
2610 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2611 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2612 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2618 case STRICT_LOW_PART
:
2619 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2621 reg
= XEXP (reg
, 0);
2622 while (GET_CODE (reg
) == SUBREG
2623 || GET_CODE (reg
) == ZERO_EXTRACT
2624 || GET_CODE (reg
) == SIGN_EXTRACT
2625 || GET_CODE (reg
) == STRICT_LOW_PART
);
2626 if (GET_CODE (reg
) == MEM
)
2628 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2632 regno_last
= regno_first
= REGNO (reg
);
2633 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2634 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2638 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2640 enum machine_mode outer_mode
= GET_MODE (reg
);
2641 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2643 /* Identify the range of registers affected. This is moderately
2644 tricky for hard registers. See alter_subreg. */
2646 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2647 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2649 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2652 regno_last
= (regno_first
2653 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2655 /* Since we've just adjusted the register number ranges, make
2656 sure REG matches. Otherwise some_was_live will be clear
2657 when it shouldn't have been, and we'll create incorrect
2658 REG_UNUSED notes. */
2659 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2663 /* If the number of words in the subreg is less than the number
2664 of words in the full register, we have a well-defined partial
2665 set. Otherwise the high bits are undefined.
2667 This is only really applicable to pseudos, since we just took
2668 care of multi-word hard registers. */
2669 if (((GET_MODE_SIZE (outer_mode
)
2670 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2671 < ((GET_MODE_SIZE (inner_mode
)
2672 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2673 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2676 reg
= SUBREG_REG (reg
);
2680 reg
= SUBREG_REG (reg
);
2687 /* If this set is a MEM, then it kills any aliased writes.
2688 If this set is a REG, then it kills any MEMs which use the reg. */
2689 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2691 if (GET_CODE (reg
) == REG
)
2692 invalidate_mems_from_set (pbi
, reg
);
2694 /* If the memory reference had embedded side effects (autoincrement
2695 address modes. Then we may need to kill some entries on the
2697 if (insn
&& GET_CODE (reg
) == MEM
)
2698 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2700 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2701 /* ??? With more effort we could track conditional memory life. */
2703 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2706 if (GET_CODE (reg
) == REG
2707 && ! (regno_first
== FRAME_POINTER_REGNUM
2708 && (! reload_completed
|| frame_pointer_needed
))
2709 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2710 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2711 && (! reload_completed
|| frame_pointer_needed
))
2713 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2714 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2718 int some_was_live
= 0, some_was_dead
= 0;
2720 for (i
= regno_first
; i
<= regno_last
; ++i
)
2722 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2725 /* Order of the set operation matters here since both
2726 sets may be the same. */
2727 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2728 if (cond
!= NULL_RTX
2729 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2730 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2732 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2734 if (code
!= CLOBBER
)
2735 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2737 some_was_live
|= needed_regno
;
2738 some_was_dead
|= ! needed_regno
;
2741 #ifdef HAVE_conditional_execution
2742 /* Consider conditional death in deciding that the register needs
2744 if (some_was_live
&& ! not_dead
2745 /* The stack pointer is never dead. Well, not strictly true,
2746 but it's very difficult to tell from here. Hopefully
2747 combine_stack_adjustments will fix up the most egregious
2749 && regno_first
!= STACK_POINTER_REGNUM
)
2751 for (i
= regno_first
; i
<= regno_last
; ++i
)
2752 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2753 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2757 /* Additional data to record if this is the final pass. */
2758 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2759 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2762 int blocknum
= pbi
->bb
->index
;
2765 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2767 y
= pbi
->reg_next_use
[regno_first
];
2769 /* The next use is no longer next, since a store intervenes. */
2770 for (i
= regno_first
; i
<= regno_last
; ++i
)
2771 pbi
->reg_next_use
[i
] = 0;
2774 if (flags
& PROP_REG_INFO
)
2776 for (i
= regno_first
; i
<= regno_last
; ++i
)
2778 /* Count (weighted) references, stores, etc. This counts a
2779 register twice if it is modified, but that is correct. */
2780 REG_N_SETS (i
) += 1;
2781 REG_N_REFS (i
) += 1;
2782 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2784 /* The insns where a reg is live are normally counted
2785 elsewhere, but we want the count to include the insn
2786 where the reg is set, and the normal counting mechanism
2787 would not count it. */
2788 REG_LIVE_LENGTH (i
) += 1;
2791 /* If this is a hard reg, record this function uses the reg. */
2792 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2794 for (i
= regno_first
; i
<= regno_last
; i
++)
2795 regs_ever_live
[i
] = 1;
2799 /* Keep track of which basic blocks each reg appears in. */
2800 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2801 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2802 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2803 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2807 if (! some_was_dead
)
2809 if (flags
& PROP_LOG_LINKS
)
2811 /* Make a logical link from the next following insn
2812 that uses this register, back to this insn.
2813 The following insns have already been processed.
2815 We don't build a LOG_LINK for hard registers containing
2816 in ASM_OPERANDs. If these registers get replaced,
2817 we might wind up changing the semantics of the insn,
2818 even if reload can make what appear to be valid
2819 assignments later. */
2820 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2821 && (regno_first
>= FIRST_PSEUDO_REGISTER
2822 || asm_noperands (PATTERN (y
)) < 0))
2823 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2828 else if (! some_was_live
)
2830 if (flags
& PROP_REG_INFO
)
2831 REG_N_DEATHS (regno_first
) += 1;
2833 if (flags
& PROP_DEATH_NOTES
)
2835 /* Note that dead stores have already been deleted
2836 when possible. If we get here, we have found a
2837 dead store that cannot be eliminated (because the
2838 same insn does something useful). Indicate this
2839 by marking the reg being set as dying here. */
2841 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2846 if (flags
& PROP_DEATH_NOTES
)
2848 /* This is a case where we have a multi-word hard register
2849 and some, but not all, of the words of the register are
2850 needed in subsequent insns. Write REG_UNUSED notes
2851 for those parts that were not needed. This case should
2854 for (i
= regno_first
; i
<= regno_last
; ++i
)
2855 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2857 = alloc_EXPR_LIST (REG_UNUSED
,
2864 /* Mark the register as being dead. */
2866 /* The stack pointer is never dead. Well, not strictly true,
2867 but it's very difficult to tell from here. Hopefully
2868 combine_stack_adjustments will fix up the most egregious
2870 && regno_first
!= STACK_POINTER_REGNUM
)
2872 for (i
= regno_first
; i
<= regno_last
; ++i
)
2873 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2874 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2877 else if (GET_CODE (reg
) == REG
)
2879 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2880 pbi
->reg_next_use
[regno_first
] = 0;
2883 /* If this is the last pass and this is a SCRATCH, show it will be dying
2884 here and count it. */
2885 else if (GET_CODE (reg
) == SCRATCH
)
2887 if (flags
& PROP_DEATH_NOTES
)
2889 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2893 #ifdef HAVE_conditional_execution
2894 /* Mark REGNO conditionally dead.
2895 Return true if the register is now unconditionally dead. */
2898 mark_regno_cond_dead (pbi
, regno
, cond
)
2899 struct propagate_block_info
*pbi
;
2903 /* If this is a store to a predicate register, the value of the
2904 predicate is changing, we don't know that the predicate as seen
2905 before is the same as that seen after. Flush all dependent
2906 conditions from reg_cond_dead. This will make all such
2907 conditionally live registers unconditionally live. */
2908 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2909 flush_reg_cond_reg (pbi
, regno
);
2911 /* If this is an unconditional store, remove any conditional
2912 life that may have existed. */
2913 if (cond
== NULL_RTX
)
2914 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2917 splay_tree_node node
;
2918 struct reg_cond_life_info
*rcli
;
2921 /* Otherwise this is a conditional set. Record that fact.
2922 It may have been conditionally used, or there may be a
2923 subsequent set with a complimentary condition. */
2925 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2928 /* The register was unconditionally live previously.
2929 Record the current condition as the condition under
2930 which it is dead. */
2931 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2932 rcli
->condition
= cond
;
2933 rcli
->stores
= cond
;
2934 rcli
->orig_condition
= const0_rtx
;
2935 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2936 (splay_tree_value
) rcli
);
2938 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2940 /* Not unconditionally dead. */
2945 /* The register was conditionally live previously.
2946 Add the new condition to the old. */
2947 rcli
= (struct reg_cond_life_info
*) node
->value
;
2948 ncond
= rcli
->condition
;
2949 ncond
= ior_reg_cond (ncond
, cond
, 1);
2950 if (rcli
->stores
== const0_rtx
)
2951 rcli
->stores
= cond
;
2952 else if (rcli
->stores
!= const1_rtx
)
2953 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2955 /* If the register is now unconditionally dead, remove the entry
2956 in the splay_tree. A register is unconditionally dead if the
2957 dead condition ncond is true. A register is also unconditionally
2958 dead if the sum of all conditional stores is an unconditional
2959 store (stores is true), and the dead condition is identically the
2960 same as the original dead condition initialized at the end of
2961 the block. This is a pointer compare, not an rtx_equal_p
2963 if (ncond
== const1_rtx
2964 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2965 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2968 rcli
->condition
= ncond
;
2970 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2972 /* Not unconditionally dead. */
2981 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2984 free_reg_cond_life_info (value
)
2985 splay_tree_value value
;
2987 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2991 /* Helper function for flush_reg_cond_reg. */
2994 flush_reg_cond_reg_1 (node
, data
)
2995 splay_tree_node node
;
2998 struct reg_cond_life_info
*rcli
;
2999 int *xdata
= (int *) data
;
3000 unsigned int regno
= xdata
[0];
3002 /* Don't need to search if last flushed value was farther on in
3003 the in-order traversal. */
3004 if (xdata
[1] >= (int) node
->key
)
3007 /* Splice out portions of the expression that refer to regno. */
3008 rcli
= (struct reg_cond_life_info
*) node
->value
;
3009 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
3010 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
3011 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
3013 /* If the entire condition is now false, signal the node to be removed. */
3014 if (rcli
->condition
== const0_rtx
)
3016 xdata
[1] = node
->key
;
3019 else if (rcli
->condition
== const1_rtx
)
3025 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3028 flush_reg_cond_reg (pbi
, regno
)
3029 struct propagate_block_info
*pbi
;
3036 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3037 flush_reg_cond_reg_1
, pair
) == -1)
3038 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3040 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3043 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3044 For ior/and, the ADD flag determines whether we want to add the new
3045 condition X to the old one unconditionally. If it is zero, we will
3046 only return a new expression if X allows us to simplify part of
3047 OLD, otherwise we return NULL to the caller.
3048 If ADD is nonzero, we will return a new condition in all cases. The
3049 toplevel caller of one of these functions should always pass 1 for
3053 ior_reg_cond (old
, x
, add
)
3059 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3061 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3062 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3063 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3065 if (GET_CODE (x
) == GET_CODE (old
)
3066 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3070 return gen_rtx_IOR (0, old
, x
);
3073 switch (GET_CODE (old
))
3076 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3077 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3078 if (op0
!= NULL
|| op1
!= NULL
)
3080 if (op0
== const0_rtx
)
3081 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3082 if (op1
== const0_rtx
)
3083 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3084 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3087 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3088 else if (rtx_equal_p (x
, op0
))
3089 /* (x | A) | x ~ (x | A). */
3092 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3093 else if (rtx_equal_p (x
, op1
))
3094 /* (A | x) | x ~ (A | x). */
3096 return gen_rtx_IOR (0, op0
, op1
);
3100 return gen_rtx_IOR (0, old
, x
);
3103 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3104 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3105 if (op0
!= NULL
|| op1
!= NULL
)
3107 if (op0
== const1_rtx
)
3108 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3109 if (op1
== const1_rtx
)
3110 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3111 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3114 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3115 else if (rtx_equal_p (x
, op0
))
3116 /* (x & A) | x ~ x. */
3119 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3120 else if (rtx_equal_p (x
, op1
))
3121 /* (A & x) | x ~ x. */
3123 return gen_rtx_AND (0, op0
, op1
);
3127 return gen_rtx_IOR (0, old
, x
);
3130 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3132 return not_reg_cond (op0
);
3135 return gen_rtx_IOR (0, old
, x
);
3146 enum rtx_code x_code
;
3148 if (x
== const0_rtx
)
3150 else if (x
== const1_rtx
)
3152 x_code
= GET_CODE (x
);
3155 if (GET_RTX_CLASS (x_code
) == '<'
3156 && GET_CODE (XEXP (x
, 0)) == REG
)
3158 if (XEXP (x
, 1) != const0_rtx
)
3161 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3162 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3164 return gen_rtx_NOT (0, x
);
3168 and_reg_cond (old
, x
, add
)
3174 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3176 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3177 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3178 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3180 if (GET_CODE (x
) == GET_CODE (old
)
3181 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3185 return gen_rtx_AND (0, old
, x
);
3188 switch (GET_CODE (old
))
3191 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3192 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3193 if (op0
!= NULL
|| op1
!= NULL
)
3195 if (op0
== const0_rtx
)
3196 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3197 if (op1
== const0_rtx
)
3198 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3199 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3202 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3203 else if (rtx_equal_p (x
, op0
))
3204 /* (x | A) & x ~ x. */
3207 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3208 else if (rtx_equal_p (x
, op1
))
3209 /* (A | x) & x ~ x. */
3211 return gen_rtx_IOR (0, op0
, op1
);
3215 return gen_rtx_AND (0, old
, x
);
3218 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3219 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3220 if (op0
!= NULL
|| op1
!= NULL
)
3222 if (op0
== const1_rtx
)
3223 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3224 if (op1
== const1_rtx
)
3225 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3226 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3229 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3230 else if (rtx_equal_p (x
, op0
))
3231 /* (x & A) & x ~ (x & A). */
3234 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3235 else if (rtx_equal_p (x
, op1
))
3236 /* (A & x) & x ~ (A & x). */
3238 return gen_rtx_AND (0, op0
, op1
);
3242 return gen_rtx_AND (0, old
, x
);
3245 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3247 return not_reg_cond (op0
);
3250 return gen_rtx_AND (0, old
, x
);
3257 /* Given a condition X, remove references to reg REGNO and return the
3258 new condition. The removal will be done so that all conditions
3259 involving REGNO are considered to evaluate to false. This function
3260 is used when the value of REGNO changes. */
3263 elim_reg_cond (x
, regno
)
3269 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3271 if (REGNO (XEXP (x
, 0)) == regno
)
3276 switch (GET_CODE (x
))
3279 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3280 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3281 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3283 if (op0
== const1_rtx
)
3285 if (op1
== const1_rtx
)
3287 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3289 return gen_rtx_AND (0, op0
, op1
);
3292 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3293 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3294 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3296 if (op0
== const0_rtx
)
3298 if (op1
== const0_rtx
)
3300 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3302 return gen_rtx_IOR (0, op0
, op1
);
3305 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3306 if (op0
== const0_rtx
)
3308 if (op0
== const1_rtx
)
3310 if (op0
!= XEXP (x
, 0))
3311 return not_reg_cond (op0
);
3318 #endif /* HAVE_conditional_execution */
3322 /* Try to substitute the auto-inc expression INC as the address inside
3323 MEM which occurs in INSN. Currently, the address of MEM is an expression
3324 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3325 that has a single set whose source is a PLUS of INCR_REG and something
3329 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3330 struct propagate_block_info
*pbi
;
3331 rtx inc
, insn
, mem
, incr
, incr_reg
;
3333 int regno
= REGNO (incr_reg
);
3334 rtx set
= single_set (incr
);
3335 rtx q
= SET_DEST (set
);
3336 rtx y
= SET_SRC (set
);
3337 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3339 /* Make sure this reg appears only once in this insn. */
3340 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3343 if (dead_or_set_p (incr
, incr_reg
)
3344 /* Mustn't autoinc an eliminable register. */
3345 && (regno
>= FIRST_PSEUDO_REGISTER
3346 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3348 /* This is the simple case. Try to make the auto-inc. If
3349 we can't, we are done. Otherwise, we will do any
3350 needed updates below. */
3351 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3354 else if (GET_CODE (q
) == REG
3355 /* PREV_INSN used here to check the semi-open interval
3357 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3358 /* We must also check for sets of q as q may be
3359 a call clobbered hard register and there may
3360 be a call between PREV_INSN (insn) and incr. */
3361 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3363 /* We have *p followed sometime later by q = p+size.
3364 Both p and q must be live afterward,
3365 and q is not used between INSN and its assignment.
3366 Change it to q = p, ...*q..., q = q+size.
3367 Then fall into the usual case. */
3371 emit_move_insn (q
, incr_reg
);
3372 insns
= get_insns ();
3375 /* If we can't make the auto-inc, or can't make the
3376 replacement into Y, exit. There's no point in making
3377 the change below if we can't do the auto-inc and doing
3378 so is not correct in the pre-inc case. */
3381 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3382 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3383 if (! apply_change_group ())
3386 /* We now know we'll be doing this change, so emit the
3387 new insn(s) and do the updates. */
3388 emit_insn_before (insns
, insn
);
3390 if (pbi
->bb
->head
== insn
)
3391 pbi
->bb
->head
= insns
;
3393 /* INCR will become a NOTE and INSN won't contain a
3394 use of INCR_REG. If a use of INCR_REG was just placed in
3395 the insn before INSN, make that the next use.
3396 Otherwise, invalidate it. */
3397 if (GET_CODE (PREV_INSN (insn
)) == INSN
3398 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3399 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3400 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3402 pbi
->reg_next_use
[regno
] = 0;
3407 /* REGNO is now used in INCR which is below INSN, but
3408 it previously wasn't live here. If we don't mark
3409 it as live, we'll put a REG_DEAD note for it
3410 on this insn, which is incorrect. */
3411 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3413 /* If there are any calls between INSN and INCR, show
3414 that REGNO now crosses them. */
3415 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3416 if (GET_CODE (temp
) == CALL_INSN
)
3417 REG_N_CALLS_CROSSED (regno
)++;
3419 /* Invalidate alias info for Q since we just changed its value. */
3420 clear_reg_alias_info (q
);
3425 /* If we haven't returned, it means we were able to make the
3426 auto-inc, so update the status. First, record that this insn
3427 has an implicit side effect. */
3429 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3431 /* Modify the old increment-insn to simply copy
3432 the already-incremented value of our register. */
3433 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3436 /* If that makes it a no-op (copying the register into itself) delete
3437 it so it won't appear to be a "use" and a "set" of this
3439 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3441 /* If the original source was dead, it's dead now. */
3444 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3446 remove_note (incr
, note
);
3447 if (XEXP (note
, 0) != incr_reg
)
3448 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3451 PUT_CODE (incr
, NOTE
);
3452 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3453 NOTE_SOURCE_FILE (incr
) = 0;
3456 if (regno
>= FIRST_PSEUDO_REGISTER
)
3458 /* Count an extra reference to the reg. When a reg is
3459 incremented, spilling it is worse, so we want to make
3460 that less likely. */
3461 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3463 /* Count the increment as a setting of the register,
3464 even though it isn't a SET in rtl. */
3465 REG_N_SETS (regno
)++;
3469 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3473 find_auto_inc (pbi
, x
, insn
)
3474 struct propagate_block_info
*pbi
;
3478 rtx addr
= XEXP (x
, 0);
3479 HOST_WIDE_INT offset
= 0;
3480 rtx set
, y
, incr
, inc_val
;
3482 int size
= GET_MODE_SIZE (GET_MODE (x
));
3484 if (GET_CODE (insn
) == JUMP_INSN
)
3487 /* Here we detect use of an index register which might be good for
3488 postincrement, postdecrement, preincrement, or predecrement. */
3490 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3491 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3493 if (GET_CODE (addr
) != REG
)
3496 regno
= REGNO (addr
);
3498 /* Is the next use an increment that might make auto-increment? */
3499 incr
= pbi
->reg_next_use
[regno
];
3500 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3502 set
= single_set (incr
);
3503 if (set
== 0 || GET_CODE (set
) != SET
)
3507 if (GET_CODE (y
) != PLUS
)
3510 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3511 inc_val
= XEXP (y
, 1);
3512 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3513 inc_val
= XEXP (y
, 0);
3517 if (GET_CODE (inc_val
) == CONST_INT
)
3519 if (HAVE_POST_INCREMENT
3520 && (INTVAL (inc_val
) == size
&& offset
== 0))
3521 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3523 else if (HAVE_POST_DECREMENT
3524 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3525 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3527 else if (HAVE_PRE_INCREMENT
3528 && (INTVAL (inc_val
) == size
&& offset
== size
))
3529 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3531 else if (HAVE_PRE_DECREMENT
3532 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3533 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3535 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3536 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3537 gen_rtx_PLUS (Pmode
,
3540 insn
, x
, incr
, addr
);
3541 else if (HAVE_PRE_MODIFY_DISP
&& offset
== INTVAL (inc_val
))
3542 attempt_auto_inc (pbi
, gen_rtx_PRE_MODIFY (Pmode
, addr
,
3543 gen_rtx_PLUS (Pmode
,
3546 insn
, x
, incr
, addr
);
3548 else if (GET_CODE (inc_val
) == REG
3549 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3553 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3554 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3555 gen_rtx_PLUS (Pmode
,
3558 insn
, x
, incr
, addr
);
3562 #endif /* AUTO_INC_DEC */
3565 mark_used_reg (pbi
, reg
, cond
, insn
)
3566 struct propagate_block_info
*pbi
;
3568 rtx cond ATTRIBUTE_UNUSED
;
3571 unsigned int regno_first
, regno_last
, i
;
3572 int some_was_live
, some_was_dead
, some_not_set
;
3574 regno_last
= regno_first
= REGNO (reg
);
3575 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3576 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3578 /* Find out if any of this register is live after this instruction. */
3579 some_was_live
= some_was_dead
= 0;
3580 for (i
= regno_first
; i
<= regno_last
; ++i
)
3582 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3583 some_was_live
|= needed_regno
;
3584 some_was_dead
|= ! needed_regno
;
3587 /* Find out if any of the register was set this insn. */
3589 for (i
= regno_first
; i
<= regno_last
; ++i
)
3590 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3592 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3594 /* Record where each reg is used, so when the reg is set we know
3595 the next insn that uses it. */
3596 pbi
->reg_next_use
[regno_first
] = insn
;
3599 if (pbi
->flags
& PROP_REG_INFO
)
3601 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3603 /* If this is a register we are going to try to eliminate,
3604 don't mark it live here. If we are successful in
3605 eliminating it, it need not be live unless it is used for
3606 pseudos, in which case it will have been set live when it
3607 was allocated to the pseudos. If the register will not
3608 be eliminated, reload will set it live at that point.
3610 Otherwise, record that this function uses this register. */
3611 /* ??? The PPC backend tries to "eliminate" on the pic
3612 register to itself. This should be fixed. In the mean
3613 time, hack around it. */
3615 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3616 && (regno_first
== FRAME_POINTER_REGNUM
3617 || regno_first
== ARG_POINTER_REGNUM
)))
3618 for (i
= regno_first
; i
<= regno_last
; ++i
)
3619 regs_ever_live
[i
] = 1;
3623 /* Keep track of which basic block each reg appears in. */
3625 int blocknum
= pbi
->bb
->index
;
3626 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3627 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3628 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3629 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3631 /* Count (weighted) number of uses of each reg. */
3632 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3633 REG_N_REFS (regno_first
)++;
3637 /* Record and count the insns in which a reg dies. If it is used in
3638 this insn and was dead below the insn then it dies in this insn.
3639 If it was set in this insn, we do not make a REG_DEAD note;
3640 likewise if we already made such a note. */
3641 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3645 /* Check for the case where the register dying partially
3646 overlaps the register set by this insn. */
3647 if (regno_first
!= regno_last
)
3648 for (i
= regno_first
; i
<= regno_last
; ++i
)
3649 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3651 /* If none of the words in X is needed, make a REG_DEAD note.
3652 Otherwise, we must make partial REG_DEAD notes. */
3653 if (! some_was_live
)
3655 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3656 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3658 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3660 if (pbi
->flags
& PROP_REG_INFO
)
3661 REG_N_DEATHS (regno_first
)++;
3665 /* Don't make a REG_DEAD note for a part of a register
3666 that is set in the insn. */
3667 for (i
= regno_first
; i
<= regno_last
; ++i
)
3668 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3669 && ! dead_or_set_regno_p (insn
, i
))
3671 = alloc_EXPR_LIST (REG_DEAD
,
3677 /* Mark the register as being live. */
3678 for (i
= regno_first
; i
<= regno_last
; ++i
)
3680 #ifdef HAVE_conditional_execution
3681 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3684 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3686 #ifdef HAVE_conditional_execution
3687 /* If this is a conditional use, record that fact. If it is later
3688 conditionally set, we'll know to kill the register. */
3689 if (cond
!= NULL_RTX
)
3691 splay_tree_node node
;
3692 struct reg_cond_life_info
*rcli
;
3697 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3700 /* The register was unconditionally live previously.
3701 No need to do anything. */
3705 /* The register was conditionally live previously.
3706 Subtract the new life cond from the old death cond. */
3707 rcli
= (struct reg_cond_life_info
*) node
->value
;
3708 ncond
= rcli
->condition
;
3709 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3711 /* If the register is now unconditionally live,
3712 remove the entry in the splay_tree. */
3713 if (ncond
== const0_rtx
)
3714 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3717 rcli
->condition
= ncond
;
3718 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3719 REGNO (XEXP (cond
, 0)));
3725 /* The register was not previously live at all. Record
3726 the condition under which it is still dead. */
3727 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3728 rcli
->condition
= not_reg_cond (cond
);
3729 rcli
->stores
= const0_rtx
;
3730 rcli
->orig_condition
= const0_rtx
;
3731 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3732 (splay_tree_value
) rcli
);
3734 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3737 else if (this_was_live
)
3739 /* The register may have been conditionally live previously, but
3740 is now unconditionally live. Remove it from the conditionally
3741 dead list, so that a conditional set won't cause us to think
3743 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3749 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3750 This is done assuming the registers needed from X are those that
3751 have 1-bits in PBI->REG_LIVE.
3753 INSN is the containing instruction. If INSN is dead, this function
3757 mark_used_regs (pbi
, x
, cond
, insn
)
3758 struct propagate_block_info
*pbi
;
3763 int flags
= pbi
->flags
;
3768 code
= GET_CODE (x
);
3789 /* If we are clobbering a MEM, mark any registers inside the address
3791 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3792 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3796 /* Don't bother watching stores to mems if this is not the
3797 final pass. We'll not be deleting dead stores this round. */
3798 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3800 /* Invalidate the data for the last MEM stored, but only if MEM is
3801 something that can be stored into. */
3802 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3803 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3804 /* Needn't clear the memory set list. */
3808 rtx temp
= pbi
->mem_set_list
;
3809 rtx prev
= NULL_RTX
;
3814 next
= XEXP (temp
, 1);
3815 if (anti_dependence (XEXP (temp
, 0), x
))
3817 /* Splice temp out of the list. */
3819 XEXP (prev
, 1) = next
;
3821 pbi
->mem_set_list
= next
;
3822 free_EXPR_LIST_node (temp
);
3823 pbi
->mem_set_list_len
--;
3831 /* If the memory reference had embedded side effects (autoincrement
3832 address modes. Then we may need to kill some entries on the
3835 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3839 if (flags
& PROP_AUTOINC
)
3840 find_auto_inc (pbi
, x
, insn
);
3845 #ifdef CANNOT_CHANGE_MODE_CLASS
3846 if (GET_CODE (SUBREG_REG (x
)) == REG
3847 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
)
3848 SET_REGNO_REG_SET (&subregs_of_mode
[GET_MODE (x
)],
3849 REGNO (SUBREG_REG (x
)));
3852 /* While we're here, optimize this case. */
3854 if (GET_CODE (x
) != REG
)
3859 /* See a register other than being set => mark it as needed. */
3860 mark_used_reg (pbi
, x
, cond
, insn
);
3865 rtx testreg
= SET_DEST (x
);
3868 /* If storing into MEM, don't show it as being used. But do
3869 show the address as being used. */
3870 if (GET_CODE (testreg
) == MEM
)
3873 if (flags
& PROP_AUTOINC
)
3874 find_auto_inc (pbi
, testreg
, insn
);
3876 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3877 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3881 /* Storing in STRICT_LOW_PART is like storing in a reg
3882 in that this SET might be dead, so ignore it in TESTREG.
3883 but in some other ways it is like using the reg.
3885 Storing in a SUBREG or a bit field is like storing the entire
3886 register in that if the register's value is not used
3887 then this SET is not needed. */
3888 while (GET_CODE (testreg
) == STRICT_LOW_PART
3889 || GET_CODE (testreg
) == ZERO_EXTRACT
3890 || GET_CODE (testreg
) == SIGN_EXTRACT
3891 || GET_CODE (testreg
) == SUBREG
)
3893 #ifdef CANNOT_CHANGE_MODE_CLASS
3894 if (GET_CODE (testreg
) == SUBREG
3895 && GET_CODE (SUBREG_REG (testreg
)) == REG
3896 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
)
3897 SET_REGNO_REG_SET (&subregs_of_mode
[GET_MODE (testreg
)],
3898 REGNO (SUBREG_REG (testreg
)));
3901 /* Modifying a single register in an alternate mode
3902 does not use any of the old value. But these other
3903 ways of storing in a register do use the old value. */
3904 if (GET_CODE (testreg
) == SUBREG
3905 && !((REG_BYTES (SUBREG_REG (testreg
))
3906 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3907 > (REG_BYTES (testreg
)
3908 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3913 testreg
= XEXP (testreg
, 0);
3916 /* If this is a store into a register or group of registers,
3917 recursively scan the value being stored. */
3919 if ((GET_CODE (testreg
) == PARALLEL
3920 && GET_MODE (testreg
) == BLKmode
)
3921 || (GET_CODE (testreg
) == REG
3922 && (regno
= REGNO (testreg
),
3923 ! (regno
== FRAME_POINTER_REGNUM
3924 && (! reload_completed
|| frame_pointer_needed
)))
3925 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3926 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3927 && (! reload_completed
|| frame_pointer_needed
))
3929 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3930 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3935 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3936 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3943 case UNSPEC_VOLATILE
:
3947 /* Traditional and volatile asm instructions must be considered to use
3948 and clobber all hard registers, all pseudo-registers and all of
3949 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3951 Consider for instance a volatile asm that changes the fpu rounding
3952 mode. An insn should not be moved across this even if it only uses
3953 pseudo-regs because it might give an incorrectly rounded result.
3955 ?!? Unfortunately, marking all hard registers as live causes massive
3956 problems for the register allocator and marking all pseudos as live
3957 creates mountains of uninitialized variable warnings.
3959 So for now, just clear the memory set list and mark any regs
3960 we can find in ASM_OPERANDS as used. */
3961 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3963 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3964 pbi
->mem_set_list_len
= 0;
3967 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3968 We can not just fall through here since then we would be confused
3969 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3970 traditional asms unlike their normal usage. */
3971 if (code
== ASM_OPERANDS
)
3975 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3976 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3982 if (cond
!= NULL_RTX
)
3985 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3987 cond
= COND_EXEC_TEST (x
);
3988 x
= COND_EXEC_CODE (x
);
3992 /* We _do_not_ want to scan operands of phi nodes. Operands of
3993 a phi function are evaluated only when control reaches this
3994 block along a particular edge. Therefore, regs that appear
3995 as arguments to phi should not be added to the global live at
4003 /* Recursively scan the operands of this expression. */
4006 const char * const fmt
= GET_RTX_FORMAT (code
);
4009 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4013 /* Tail recursive case: save a function call level. */
4019 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
4021 else if (fmt
[i
] == 'E')
4024 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4025 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4034 try_pre_increment_1 (pbi
, insn
)
4035 struct propagate_block_info
*pbi
;
4038 /* Find the next use of this reg. If in same basic block,
4039 make it do pre-increment or pre-decrement if appropriate. */
4040 rtx x
= single_set (insn
);
4041 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4042 * INTVAL (XEXP (SET_SRC (x
), 1)));
4043 int regno
= REGNO (SET_DEST (x
));
4044 rtx y
= pbi
->reg_next_use
[regno
];
4046 && SET_DEST (x
) != stack_pointer_rtx
4047 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4048 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4049 mode would be better. */
4050 && ! dead_or_set_p (y
, SET_DEST (x
))
4051 && try_pre_increment (y
, SET_DEST (x
), amount
))
4053 /* We have found a suitable auto-increment and already changed
4054 insn Y to do it. So flush this increment instruction. */
4055 propagate_block_delete_insn (insn
);
4057 /* Count a reference to this reg for the increment insn we are
4058 deleting. When a reg is incremented, spilling it is worse,
4059 so we want to make that less likely. */
4060 if (regno
>= FIRST_PSEUDO_REGISTER
)
4062 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4063 REG_N_SETS (regno
)++;
4066 /* Flush any remembered memories depending on the value of
4067 the incremented register. */
4068 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4075 /* Try to change INSN so that it does pre-increment or pre-decrement
4076 addressing on register REG in order to add AMOUNT to REG.
4077 AMOUNT is negative for pre-decrement.
4078 Returns 1 if the change could be made.
4079 This checks all about the validity of the result of modifying INSN. */
4082 try_pre_increment (insn
, reg
, amount
)
4084 HOST_WIDE_INT amount
;
4088 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4089 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4091 /* Nonzero if we can try to make a post-increment or post-decrement.
4092 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4093 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4094 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4097 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4100 /* From the sign of increment, see which possibilities are conceivable
4101 on this target machine. */
4102 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4104 if (HAVE_POST_INCREMENT
&& amount
> 0)
4107 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4109 if (HAVE_POST_DECREMENT
&& amount
< 0)
4112 if (! (pre_ok
|| post_ok
))
4115 /* It is not safe to add a side effect to a jump insn
4116 because if the incremented register is spilled and must be reloaded
4117 there would be no way to store the incremented value back in memory. */
4119 if (GET_CODE (insn
) == JUMP_INSN
)
4124 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4125 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4127 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4131 if (use
== 0 || use
== (rtx
) (size_t) 1)
4134 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4137 /* See if this combination of instruction and addressing mode exists. */
4138 if (! validate_change (insn
, &XEXP (use
, 0),
4139 gen_rtx_fmt_e (amount
> 0
4140 ? (do_post
? POST_INC
: PRE_INC
)
4141 : (do_post
? POST_DEC
: PRE_DEC
),
4145 /* Record that this insn now has an implicit side effect on X. */
4146 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4150 #endif /* AUTO_INC_DEC */
4152 /* Find the place in the rtx X where REG is used as a memory address.
4153 Return the MEM rtx that so uses it.
4154 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4155 (plus REG (const_int PLUSCONST)).
4157 If such an address does not appear, return 0.
4158 If REG appears more than once, or is used other than in such an address,
4162 find_use_as_address (x
, reg
, plusconst
)
4165 HOST_WIDE_INT plusconst
;
4167 enum rtx_code code
= GET_CODE (x
);
4168 const char * const fmt
= GET_RTX_FORMAT (code
);
4173 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4176 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4177 && XEXP (XEXP (x
, 0), 0) == reg
4178 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4179 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4182 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4184 /* If REG occurs inside a MEM used in a bit-field reference,
4185 that is unacceptable. */
4186 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4187 return (rtx
) (size_t) 1;
4191 return (rtx
) (size_t) 1;
4193 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4197 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4201 return (rtx
) (size_t) 1;
4203 else if (fmt
[i
] == 'E')
4206 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4208 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4212 return (rtx
) (size_t) 1;
4220 /* Write information about registers and basic blocks into FILE.
4221 This is part of making a debugging dump. */
4224 dump_regset (r
, outf
)
4231 fputs (" (nil)", outf
);
4235 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4237 fprintf (outf
, " %d", i
);
4238 if (i
< FIRST_PSEUDO_REGISTER
)
4239 fprintf (outf
, " [%s]",
4244 /* Print a human-readable representation of R on the standard error
4245 stream. This function is designed to be used from within the
4252 dump_regset (r
, stderr
);
4253 putc ('\n', stderr
);
4256 /* Recompute register set/reference counts immediately prior to register
4259 This avoids problems with set/reference counts changing to/from values
4260 which have special meanings to the register allocators.
4262 Additionally, the reference counts are the primary component used by the
4263 register allocators to prioritize pseudos for allocation to hard regs.
4264 More accurate reference counts generally lead to better register allocation.
4266 F is the first insn to be scanned.
4268 LOOP_STEP denotes how much loop_depth should be incremented per
4269 loop nesting level in order to increase the ref count more for
4270 references in a loop.
4272 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4273 possibly other information which is used by the register allocators. */
4276 recompute_reg_usage (f
, loop_step
)
4277 rtx f ATTRIBUTE_UNUSED
;
4278 int loop_step ATTRIBUTE_UNUSED
;
4280 allocate_reg_life_data ();
4281 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4284 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4285 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4286 of the number of registers that died. */
4289 count_or_remove_death_notes (blocks
, kill
)
4296 FOR_EACH_BB_REVERSE (bb
)
4300 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4303 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4307 rtx
*pprev
= ®_NOTES (insn
);
4312 switch (REG_NOTE_KIND (link
))
4315 if (GET_CODE (XEXP (link
, 0)) == REG
)
4317 rtx reg
= XEXP (link
, 0);
4320 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4323 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4331 rtx next
= XEXP (link
, 1);
4332 free_EXPR_LIST_node (link
);
4333 *pprev
= link
= next
;
4339 pprev
= &XEXP (link
, 1);
4346 if (insn
== bb
->end
)
4353 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4354 if blocks is NULL. */
4357 clear_log_links (blocks
)
4365 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4367 free_INSN_LIST_list (&LOG_LINKS (insn
));
4370 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4372 basic_block bb
= BASIC_BLOCK (i
);
4374 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4375 insn
= NEXT_INSN (insn
))
4377 free_INSN_LIST_list (&LOG_LINKS (insn
));
4381 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4382 correspond to the hard registers, if any, set in that map. This
4383 could be done far more efficiently by having all sorts of special-cases
4384 with moving single words, but probably isn't worth the trouble. */
4387 reg_set_to_hard_reg_set (to
, from
)
4393 EXECUTE_IF_SET_IN_BITMAP
4396 if (i
>= FIRST_PSEUDO_REGISTER
)
4398 SET_HARD_REG_BIT (*to
, i
);