1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003 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 debug_flow_info
PARAMS ((void));
337 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
339 static int invalidate_mems_from_autoinc
PARAMS ((rtx
*, void *));
340 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
342 static void clear_log_links
PARAMS ((sbitmap
));
346 check_function_return_warnings ()
348 if (warn_missing_noreturn
349 && !TREE_THIS_VOLATILE (cfun
->decl
)
350 && EXIT_BLOCK_PTR
->pred
== NULL
351 && (lang_missing_noreturn_ok_p
352 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
353 warning ("function might be possible candidate for attribute `noreturn'");
355 /* If we have a path to EXIT, then we do return. */
356 if (TREE_THIS_VOLATILE (cfun
->decl
)
357 && EXIT_BLOCK_PTR
->pred
!= NULL
)
358 warning ("`noreturn' function does return");
360 /* If the clobber_return_insn appears in some basic block, then we
361 do reach the end without returning a value. */
362 else if (warn_return_type
363 && cfun
->x_clobber_return_insn
!= NULL
364 && EXIT_BLOCK_PTR
->pred
!= NULL
)
366 int max_uid
= get_max_uid ();
368 /* If clobber_return_insn was excised by jump1, then renumber_insns
369 can make max_uid smaller than the number still recorded in our rtx.
370 That's fine, since this is a quick way of verifying that the insn
371 is no longer in the chain. */
372 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
376 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
377 if (insn
== cfun
->x_clobber_return_insn
)
379 warning ("control reaches end of non-void function");
386 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
387 note associated with the BLOCK. */
390 first_insn_after_basic_block_note (block
)
395 /* Get the first instruction in the block. */
398 if (insn
== NULL_RTX
)
400 if (GET_CODE (insn
) == CODE_LABEL
)
401 insn
= NEXT_INSN (insn
);
402 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
405 return NEXT_INSN (insn
);
408 /* Perform data flow analysis.
409 F is the first insn of the function; FLAGS is a set of PROP_* flags
410 to be used in accumulating flow info. */
413 life_analysis (f
, file
, flags
)
418 #ifdef ELIMINABLE_REGS
420 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
423 /* Record which registers will be eliminated. We use this in
426 CLEAR_HARD_REG_SET (elim_reg_set
);
428 #ifdef ELIMINABLE_REGS
429 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
430 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
432 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
436 #ifdef CANNOT_CHANGE_MODE_CLASS
437 if (flags
& PROP_REG_INFO
)
438 bitmap_initialize (&subregs_of_mode
, 1);
442 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
444 /* The post-reload life analysis have (on a global basis) the same
445 registers live as was computed by reload itself. elimination
446 Otherwise offsets and such may be incorrect.
448 Reload will make some registers as live even though they do not
451 We don't want to create new auto-incs after reload, since they
452 are unlikely to be useful and can cause problems with shared
454 if (reload_completed
)
455 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
457 /* We want alias analysis information for local dead store elimination. */
458 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
459 init_alias_analysis ();
461 /* Always remove no-op moves. Do this before other processing so
462 that we don't have to keep re-scanning them. */
463 delete_noop_moves (f
);
465 /* Some targets can emit simpler epilogues if they know that sp was
466 not ever modified during the function. After reload, of course,
467 we've already emitted the epilogue so there's no sense searching. */
468 if (! reload_completed
)
469 notice_stack_pointer_modification (f
);
471 /* Allocate and zero out data structures that will record the
472 data from lifetime analysis. */
473 allocate_reg_life_data ();
474 allocate_bb_life_data ();
476 /* Find the set of registers live on function exit. */
477 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
479 /* "Update" life info from zero. It'd be nice to begin the
480 relaxation with just the exit and noreturn blocks, but that set
481 is not immediately handy. */
483 if (flags
& PROP_REG_INFO
)
484 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
485 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
488 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
489 end_alias_analysis ();
492 dump_flow_info (file
);
494 free_basic_block_vars (1);
496 /* Removing dead insns should've made jumptables really dead. */
497 delete_dead_jumptables ();
500 /* A subroutine of verify_wide_reg, called through for_each_rtx.
501 Search for REGNO. If found, return 2 if it is not wider than
505 verify_wide_reg_1 (px
, pregno
)
510 unsigned int regno
= *(int *) pregno
;
512 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
514 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
521 /* A subroutine of verify_local_live_at_start. Search through insns
522 of BB looking for register REGNO. */
525 verify_wide_reg (regno
, bb
)
529 rtx head
= bb
->head
, end
= bb
->end
;
535 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
543 head
= NEXT_INSN (head
);
548 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
549 dump_bb (bb
, rtl_dump_file
);
554 /* A subroutine of update_life_info. Verify that there are no untoward
555 changes in live_at_start during a local update. */
558 verify_local_live_at_start (new_live_at_start
, bb
)
559 regset new_live_at_start
;
562 if (reload_completed
)
564 /* After reload, there are no pseudos, nor subregs of multi-word
565 registers. The regsets should exactly match. */
566 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
570 fprintf (rtl_dump_file
,
571 "live_at_start mismatch in bb %d, aborting\nNew:\n",
573 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
574 fputs ("Old:\n", rtl_dump_file
);
575 dump_bb (bb
, rtl_dump_file
);
584 /* Find the set of changed registers. */
585 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
587 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
589 /* No registers should die. */
590 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
594 fprintf (rtl_dump_file
,
595 "Register %d died unexpectedly.\n", i
);
596 dump_bb (bb
, rtl_dump_file
);
601 /* Verify that the now-live register is wider than word_mode. */
602 verify_wide_reg (i
, bb
);
607 /* Updates life information starting with the basic blocks set in BLOCKS.
608 If BLOCKS is null, consider it to be the universal set.
610 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
611 we are only expecting local modifications to basic blocks. If we find
612 extra registers live at the beginning of a block, then we either killed
613 useful data, or we have a broken split that wants data not provided.
614 If we find registers removed from live_at_start, that means we have
615 a broken peephole that is killing a register it shouldn't.
617 ??? This is not true in one situation -- when a pre-reload splitter
618 generates subregs of a multi-word pseudo, current life analysis will
619 lose the kill. So we _can_ have a pseudo go live. How irritating.
621 Including PROP_REG_INFO does not properly refresh regs_ever_live
622 unless the caller resets it to zero. */
625 update_life_info (blocks
, extent
, prop_flags
)
627 enum update_life_extent extent
;
631 regset_head tmp_head
;
633 int stabilized_prop_flags
= prop_flags
;
636 tmp
= INITIALIZE_REG_SET (tmp_head
);
639 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
640 ? TV_LIFE_UPDATE
: TV_LIFE
);
642 /* Changes to the CFG are only allowed when
643 doing a global update for the entire CFG. */
644 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
645 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
648 /* For a global update, we go through the relaxation process again. */
649 if (extent
!= UPDATE_LIFE_LOCAL
)
655 calculate_global_regs_live (blocks
, blocks
,
656 prop_flags
& (PROP_SCAN_DEAD_CODE
657 | PROP_SCAN_DEAD_STORES
658 | PROP_ALLOW_CFG_CHANGES
));
660 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
661 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
664 /* Removing dead code may allow the CFG to be simplified which
665 in turn may allow for further dead code detection / removal. */
666 FOR_EACH_BB_REVERSE (bb
)
668 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
669 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
670 prop_flags
& (PROP_SCAN_DEAD_CODE
671 | PROP_SCAN_DEAD_STORES
672 | PROP_KILL_DEAD_CODE
));
675 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
676 subsequent propagate_block calls, since removing or acting as
677 removing dead code can affect global register liveness, which
678 is supposed to be finalized for this call after this loop. */
679 stabilized_prop_flags
680 &= ~(PROP_SCAN_DEAD_CODE
| PROP_SCAN_DEAD_STORES
681 | PROP_KILL_DEAD_CODE
);
686 /* We repeat regardless of what cleanup_cfg says. If there were
687 instructions deleted above, that might have been only a
688 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
689 Further improvement may be possible. */
690 cleanup_cfg (CLEANUP_EXPENSIVE
);
692 /* Zap the life information from the last round. If we don't
693 do this, we can wind up with registers that no longer appear
694 in the code being marked live at entry, which twiggs bogus
695 warnings from regno_uninitialized. */
698 CLEAR_REG_SET (bb
->global_live_at_start
);
699 CLEAR_REG_SET (bb
->global_live_at_end
);
703 /* If asked, remove notes from the blocks we'll update. */
704 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
705 count_or_remove_death_notes (blocks
, 1);
708 /* Clear log links in case we are asked to (re)compute them. */
709 if (prop_flags
& PROP_LOG_LINKS
)
710 clear_log_links (blocks
);
714 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
716 bb
= BASIC_BLOCK (i
);
718 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
719 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
721 if (extent
== UPDATE_LIFE_LOCAL
)
722 verify_local_live_at_start (tmp
, bb
);
727 FOR_EACH_BB_REVERSE (bb
)
729 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
731 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
733 if (extent
== UPDATE_LIFE_LOCAL
)
734 verify_local_live_at_start (tmp
, bb
);
740 if (prop_flags
& PROP_REG_INFO
)
742 /* The only pseudos that are live at the beginning of the function
743 are those that were not set anywhere in the function. local-alloc
744 doesn't know how to handle these correctly, so mark them as not
745 local to any one basic block. */
746 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
747 FIRST_PSEUDO_REGISTER
, i
,
748 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
750 /* We have a problem with any pseudoreg that lives across the setjmp.
751 ANSI says that if a user variable does not change in value between
752 the setjmp and the longjmp, then the longjmp preserves it. This
753 includes longjmp from a place where the pseudo appears dead.
754 (In principle, the value still exists if it is in scope.)
755 If the pseudo goes in a hard reg, some other value may occupy
756 that hard reg where this pseudo is dead, thus clobbering the pseudo.
757 Conclusion: such a pseudo must not go in a hard reg. */
758 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
759 FIRST_PSEUDO_REGISTER
, i
,
761 if (regno_reg_rtx
[i
] != 0)
763 REG_LIVE_LENGTH (i
) = -1;
764 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
768 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
769 ? TV_LIFE_UPDATE
: TV_LIFE
);
770 if (ndead
&& rtl_dump_file
)
771 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
775 /* Update life information in all blocks where BB_DIRTY is set. */
778 update_life_info_in_dirty_blocks (extent
, prop_flags
)
779 enum update_life_extent extent
;
782 sbitmap update_life_blocks
= sbitmap_alloc (last_basic_block
);
787 sbitmap_zero (update_life_blocks
);
790 if (extent
== UPDATE_LIFE_LOCAL
)
792 if (bb
->flags
& BB_DIRTY
)
794 SET_BIT (update_life_blocks
, bb
->index
);
800 /* ??? Bootstrap with -march=pentium4 fails to terminate
801 with only a partial life update. */
802 SET_BIT (update_life_blocks
, bb
->index
);
803 if (bb
->flags
& BB_DIRTY
)
809 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
811 sbitmap_free (update_life_blocks
);
815 /* Free the variables allocated by find_basic_blocks.
817 KEEP_HEAD_END_P is nonzero if basic_block_info is not to be freed. */
820 free_basic_block_vars (keep_head_end_p
)
823 if (! keep_head_end_p
)
825 if (basic_block_info
)
828 VARRAY_FREE (basic_block_info
);
831 last_basic_block
= 0;
833 ENTRY_BLOCK_PTR
->aux
= NULL
;
834 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
835 EXIT_BLOCK_PTR
->aux
= NULL
;
836 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
840 /* Delete any insns that copy a register to itself. */
843 delete_noop_moves (f
)
844 rtx f ATTRIBUTE_UNUSED
;
852 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
854 next
= NEXT_INSN (insn
);
855 if (INSN_P (insn
) && noop_move_p (insn
))
859 /* If we're about to remove the first insn of a libcall
860 then move the libcall note to the next real insn and
861 update the retval note. */
862 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
863 && XEXP (note
, 0) != insn
)
865 rtx new_libcall_insn
= next_real_insn (insn
);
866 rtx retval_note
= find_reg_note (XEXP (note
, 0),
867 REG_RETVAL
, NULL_RTX
);
868 REG_NOTES (new_libcall_insn
)
869 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
870 REG_NOTES (new_libcall_insn
));
871 XEXP (retval_note
, 0) = new_libcall_insn
;
874 delete_insn_and_edges (insn
);
879 if (nnoops
&& rtl_dump_file
)
880 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
884 /* Delete any jump tables never referenced. We can't delete them at the
885 time of removing tablejump insn as they are referenced by the preceding
886 insns computing the destination, so we delay deleting and garbagecollect
887 them once life information is computed. */
889 delete_dead_jumptables ()
892 for (insn
= get_insns (); insn
; insn
= next
)
894 next
= NEXT_INSN (insn
);
895 if (GET_CODE (insn
) == CODE_LABEL
896 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
897 && GET_CODE (next
) == JUMP_INSN
898 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
899 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
902 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
903 delete_insn (NEXT_INSN (insn
));
905 next
= NEXT_INSN (next
);
910 /* Determine if the stack pointer is constant over the life of the function.
911 Only useful before prologues have been emitted. */
914 notice_stack_pointer_modification_1 (x
, pat
, data
)
916 rtx pat ATTRIBUTE_UNUSED
;
917 void *data ATTRIBUTE_UNUSED
;
919 if (x
== stack_pointer_rtx
920 /* The stack pointer is only modified indirectly as the result
921 of a push until later in flow. See the comments in rtl.texi
922 regarding Embedded Side-Effects on Addresses. */
923 || (GET_CODE (x
) == MEM
924 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
925 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
926 current_function_sp_is_unchanging
= 0;
930 notice_stack_pointer_modification (f
)
935 /* Assume that the stack pointer is unchanging if alloca hasn't
937 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
938 if (! current_function_sp_is_unchanging
)
941 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
945 /* Check if insn modifies the stack pointer. */
946 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
948 if (! current_function_sp_is_unchanging
)
954 /* Mark a register in SET. Hard registers in large modes get all
955 of their component registers set as well. */
962 regset set
= (regset
) xset
;
963 int regno
= REGNO (reg
);
965 if (GET_MODE (reg
) == BLKmode
)
968 SET_REGNO_REG_SET (set
, regno
);
969 if (regno
< FIRST_PSEUDO_REGISTER
)
971 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
973 SET_REGNO_REG_SET (set
, regno
+ n
);
977 /* Mark those regs which are needed at the end of the function as live
978 at the end of the last basic block. */
981 mark_regs_live_at_end (set
)
986 /* If exiting needs the right stack value, consider the stack pointer
987 live at the end of the function. */
988 if ((HAVE_epilogue
&& epilogue_completed
)
989 || ! EXIT_IGNORE_STACK
990 || (! FRAME_POINTER_REQUIRED
991 && ! current_function_calls_alloca
992 && flag_omit_frame_pointer
)
993 || current_function_sp_is_unchanging
)
995 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
998 /* Mark the frame pointer if needed at the end of the function. If
999 we end up eliminating it, it will be removed from the live list
1000 of each basic block by reload. */
1002 if (! reload_completed
|| frame_pointer_needed
)
1004 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
1005 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1006 /* If they are different, also mark the hard frame pointer as live. */
1007 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
1008 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
1012 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
1013 /* Many architectures have a GP register even without flag_pic.
1014 Assume the pic register is not in use, or will be handled by
1015 other means, if it is not fixed. */
1016 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1017 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1018 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1021 /* Mark all global registers, and all registers used by the epilogue
1022 as being live at the end of the function since they may be
1023 referenced by our caller. */
1024 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1025 if (global_regs
[i
] || EPILOGUE_USES (i
))
1026 SET_REGNO_REG_SET (set
, i
);
1028 if (HAVE_epilogue
&& epilogue_completed
)
1030 /* Mark all call-saved registers that we actually used. */
1031 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1032 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1033 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1034 SET_REGNO_REG_SET (set
, i
);
1037 #ifdef EH_RETURN_DATA_REGNO
1038 /* Mark the registers that will contain data for the handler. */
1039 if (reload_completed
&& current_function_calls_eh_return
)
1042 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1043 if (regno
== INVALID_REGNUM
)
1045 SET_REGNO_REG_SET (set
, regno
);
1048 #ifdef EH_RETURN_STACKADJ_RTX
1049 if ((! HAVE_epilogue
|| ! epilogue_completed
)
1050 && current_function_calls_eh_return
)
1052 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1053 if (tmp
&& REG_P (tmp
))
1054 mark_reg (tmp
, set
);
1057 #ifdef EH_RETURN_HANDLER_RTX
1058 if ((! HAVE_epilogue
|| ! epilogue_completed
)
1059 && current_function_calls_eh_return
)
1061 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1062 if (tmp
&& REG_P (tmp
))
1063 mark_reg (tmp
, set
);
1067 /* Mark function return value. */
1068 diddle_return_value (mark_reg
, set
);
1071 /* Callback function for for_each_successor_phi. DATA is a regset.
1072 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1073 INSN, in the regset. */
1076 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1077 rtx insn ATTRIBUTE_UNUSED
;
1078 int dest_regno ATTRIBUTE_UNUSED
;
1082 regset live
= (regset
) data
;
1083 SET_REGNO_REG_SET (live
, src_regno
);
1087 /* Propagate global life info around the graph of basic blocks. Begin
1088 considering blocks with their corresponding bit set in BLOCKS_IN.
1089 If BLOCKS_IN is null, consider it the universal set.
1091 BLOCKS_OUT is set for every block that was changed. */
1094 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1095 sbitmap blocks_in
, blocks_out
;
1098 basic_block
*queue
, *qhead
, *qtail
, *qend
, bb
;
1099 regset tmp
, new_live_at_end
, invalidated_by_call
;
1100 regset_head tmp_head
, invalidated_by_call_head
;
1101 regset_head new_live_at_end_head
;
1104 /* Some passes used to forget clear aux field of basic block causing
1105 sick behavior here. */
1106 #ifdef ENABLE_CHECKING
1107 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1112 tmp
= INITIALIZE_REG_SET (tmp_head
);
1113 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1114 invalidated_by_call
= INITIALIZE_REG_SET (invalidated_by_call_head
);
1116 /* Inconveniently, this is only readily available in hard reg set form. */
1117 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1118 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1119 SET_REGNO_REG_SET (invalidated_by_call
, i
);
1121 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1122 because the `head == tail' style test for an empty queue doesn't
1123 work with a full queue. */
1124 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1126 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1128 /* Queue the blocks set in the initial mask. Do this in reverse block
1129 number order so that we are more likely for the first round to do
1130 useful work. We use AUX non-null to flag that the block is queued. */
1134 if (TEST_BIT (blocks_in
, bb
->index
))
1149 /* We clean aux when we remove the initially-enqueued bbs, but we
1150 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1152 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1155 sbitmap_zero (blocks_out
);
1157 /* We work through the queue until there are no more blocks. What
1158 is live at the end of this block is precisely the union of what
1159 is live at the beginning of all its successors. So, we set its
1160 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1161 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1162 this block by walking through the instructions in this block in
1163 reverse order and updating as we go. If that changed
1164 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1165 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1167 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1168 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1169 must either be live at the end of the block, or used within the
1170 block. In the latter case, it will certainly never disappear
1171 from GLOBAL_LIVE_AT_START. In the former case, the register
1172 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1173 for one of the successor blocks. By induction, that cannot
1175 while (qhead
!= qtail
)
1177 int rescan
, changed
;
1186 /* Begin by propagating live_at_start from the successor blocks. */
1187 CLEAR_REG_SET (new_live_at_end
);
1190 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1192 basic_block sb
= e
->dest
;
1194 /* Call-clobbered registers die across exception and
1196 /* ??? Abnormal call edges ignored for the moment, as this gets
1197 confused by sibling call edges, which crashes reg-stack. */
1198 if (e
->flags
& EDGE_EH
)
1200 bitmap_operation (tmp
, sb
->global_live_at_start
,
1201 invalidated_by_call
, BITMAP_AND_COMPL
);
1202 IOR_REG_SET (new_live_at_end
, tmp
);
1205 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1207 /* If a target saves one register in another (instead of on
1208 the stack) the save register will need to be live for EH. */
1209 if (e
->flags
& EDGE_EH
)
1210 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1212 SET_REGNO_REG_SET (new_live_at_end
, i
);
1216 /* This might be a noreturn function that throws. And
1217 even if it isn't, getting the unwind info right helps
1219 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1221 SET_REGNO_REG_SET (new_live_at_end
, i
);
1224 /* The all-important stack pointer must always be live. */
1225 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1227 /* Before reload, there are a few registers that must be forced
1228 live everywhere -- which might not already be the case for
1229 blocks within infinite loops. */
1230 if (! reload_completed
)
1232 /* Any reference to any pseudo before reload is a potential
1233 reference of the frame pointer. */
1234 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1236 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1237 /* Pseudos with argument area equivalences may require
1238 reloading via the argument pointer. */
1239 if (fixed_regs
[ARG_POINTER_REGNUM
])
1240 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1243 /* Any constant, or pseudo with constant equivalences, may
1244 require reloading from memory using the pic register. */
1245 if ((unsigned) PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1246 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1247 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1250 /* Regs used in phi nodes are not included in
1251 global_live_at_start, since they are live only along a
1252 particular edge. Set those regs that are live because of a
1253 phi node alternative corresponding to this particular block. */
1255 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1258 if (bb
== ENTRY_BLOCK_PTR
)
1260 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1264 /* On our first pass through this block, we'll go ahead and continue.
1265 Recognize first pass by local_set NULL. On subsequent passes, we
1266 get to skip out early if live_at_end wouldn't have changed. */
1268 if (bb
->local_set
== NULL
)
1270 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1271 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1276 /* If any bits were removed from live_at_end, we'll have to
1277 rescan the block. This wouldn't be necessary if we had
1278 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1279 local_live is really dependent on live_at_end. */
1280 CLEAR_REG_SET (tmp
);
1281 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1282 new_live_at_end
, BITMAP_AND_COMPL
);
1286 /* If any of the registers in the new live_at_end set are
1287 conditionally set in this basic block, we must rescan.
1288 This is because conditional lifetimes at the end of the
1289 block do not just take the live_at_end set into account,
1290 but also the liveness at the start of each successor
1291 block. We can miss changes in those sets if we only
1292 compare the new live_at_end against the previous one. */
1293 CLEAR_REG_SET (tmp
);
1294 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1295 bb
->cond_local_set
, BITMAP_AND
);
1300 /* Find the set of changed bits. Take this opportunity
1301 to notice that this set is empty and early out. */
1302 CLEAR_REG_SET (tmp
);
1303 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1304 new_live_at_end
, BITMAP_XOR
);
1308 /* If any of the changed bits overlap with local_set,
1309 we'll have to rescan the block. Detect overlap by
1310 the AND with ~local_set turning off bits. */
1311 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1316 /* Let our caller know that BB changed enough to require its
1317 death notes updated. */
1319 SET_BIT (blocks_out
, bb
->index
);
1323 /* Add to live_at_start the set of all registers in
1324 new_live_at_end that aren't in the old live_at_end. */
1326 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1328 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1330 changed
= bitmap_operation (bb
->global_live_at_start
,
1331 bb
->global_live_at_start
,
1338 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1340 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1341 into live_at_start. */
1342 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1343 bb
->cond_local_set
, flags
);
1345 /* If live_at start didn't change, no need to go farther. */
1346 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1349 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1352 /* Queue all predecessors of BB so that we may re-examine
1353 their live_at_end. */
1354 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1356 basic_block pb
= e
->src
;
1357 if (pb
->aux
== NULL
)
1368 FREE_REG_SET (new_live_at_end
);
1369 FREE_REG_SET (invalidated_by_call
);
1373 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1375 basic_block bb
= BASIC_BLOCK (i
);
1376 FREE_REG_SET (bb
->local_set
);
1377 FREE_REG_SET (bb
->cond_local_set
);
1384 FREE_REG_SET (bb
->local_set
);
1385 FREE_REG_SET (bb
->cond_local_set
);
1393 /* This structure is used to pass parameters to and from the
1394 the function find_regno_partial(). It is used to pass in the
1395 register number we are looking, as well as to return any rtx
1399 unsigned regno_to_find
;
1401 } find_regno_partial_param
;
1404 /* Find the rtx for the reg numbers specified in 'data' if it is
1405 part of an expression which only uses part of the register. Return
1406 it in the structure passed in. */
1408 find_regno_partial (ptr
, data
)
1412 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1413 unsigned reg
= param
->regno_to_find
;
1414 param
->retval
= NULL_RTX
;
1416 if (*ptr
== NULL_RTX
)
1419 switch (GET_CODE (*ptr
))
1423 case STRICT_LOW_PART
:
1424 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1426 param
->retval
= XEXP (*ptr
, 0);
1432 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1433 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1435 param
->retval
= SUBREG_REG (*ptr
);
1447 /* Process all immediate successors of the entry block looking for pseudo
1448 registers which are live on entry. Find all of those whose first
1449 instance is a partial register reference of some kind, and initialize
1450 them to 0 after the entry block. This will prevent bit sets within
1451 registers whose value is unknown, and may contain some kind of sticky
1452 bits we don't want. */
1455 initialize_uninitialized_subregs ()
1459 int reg
, did_something
= 0;
1460 find_regno_partial_param param
;
1462 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1464 basic_block bb
= e
->dest
;
1465 regset map
= bb
->global_live_at_start
;
1466 EXECUTE_IF_SET_IN_REG_SET (map
,
1467 FIRST_PSEUDO_REGISTER
, reg
,
1469 int uid
= REGNO_FIRST_UID (reg
);
1472 /* Find an insn which mentions the register we are looking for.
1473 Its preferable to have an instance of the register's rtl since
1474 there may be various flags set which we need to duplicate.
1475 If we can't find it, its probably an automatic whose initial
1476 value doesn't matter, or hopefully something we don't care about. */
1477 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1481 /* Found the insn, now get the REG rtx, if we can. */
1482 param
.regno_to_find
= reg
;
1483 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1484 if (param
.retval
!= NULL_RTX
)
1487 emit_move_insn (param
.retval
,
1488 CONST0_RTX (GET_MODE (param
.retval
)));
1489 insn
= get_insns ();
1491 insert_insn_on_edge (insn
, e
);
1499 commit_edge_insertions ();
1500 return did_something
;
1504 /* Subroutines of life analysis. */
1506 /* Allocate the permanent data structures that represent the results
1507 of life analysis. Not static since used also for stupid life analysis. */
1510 allocate_bb_life_data ()
1514 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
1516 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1517 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1520 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1524 allocate_reg_life_data ()
1528 max_regno
= max_reg_num ();
1530 /* Recalculate the register space, in case it has grown. Old style
1531 vector oriented regsets would set regset_{size,bytes} here also. */
1532 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1534 /* Reset all the data we'll collect in propagate_block and its
1536 for (i
= 0; i
< max_regno
; i
++)
1540 REG_N_DEATHS (i
) = 0;
1541 REG_N_CALLS_CROSSED (i
) = 0;
1542 REG_LIVE_LENGTH (i
) = 0;
1544 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1548 /* Delete dead instructions for propagate_block. */
1551 propagate_block_delete_insn (insn
)
1554 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1556 /* If the insn referred to a label, and that label was attached to
1557 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1558 pretty much mandatory to delete it, because the ADDR_VEC may be
1559 referencing labels that no longer exist.
1561 INSN may reference a deleted label, particularly when a jump
1562 table has been optimized into a direct jump. There's no
1563 real good way to fix up the reference to the deleted label
1564 when the label is deleted, so we just allow it here. */
1566 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1568 rtx label
= XEXP (inote
, 0);
1571 /* The label may be forced if it has been put in the constant
1572 pool. If that is the only use we must discard the table
1573 jump following it, but not the label itself. */
1574 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1575 && (next
= next_nonnote_insn (label
)) != NULL
1576 && GET_CODE (next
) == JUMP_INSN
1577 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1578 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1580 rtx pat
= PATTERN (next
);
1581 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1582 int len
= XVECLEN (pat
, diff_vec_p
);
1585 for (i
= 0; i
< len
; i
++)
1586 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1588 delete_insn_and_edges (next
);
1593 delete_insn_and_edges (insn
);
1597 /* Delete dead libcalls for propagate_block. Return the insn
1598 before the libcall. */
1601 propagate_block_delete_libcall ( insn
, note
)
1604 rtx first
= XEXP (note
, 0);
1605 rtx before
= PREV_INSN (first
);
1607 delete_insn_chain_and_edges (first
, insn
);
1612 /* Update the life-status of regs for one insn. Return the previous insn. */
1615 propagate_one_insn (pbi
, insn
)
1616 struct propagate_block_info
*pbi
;
1619 rtx prev
= PREV_INSN (insn
);
1620 int flags
= pbi
->flags
;
1621 int insn_is_dead
= 0;
1622 int libcall_is_dead
= 0;
1626 if (! INSN_P (insn
))
1629 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1630 if (flags
& PROP_SCAN_DEAD_CODE
)
1632 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1633 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1634 && libcall_dead_p (pbi
, note
, insn
));
1637 /* If an instruction consists of just dead store(s) on final pass,
1639 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1641 /* If we're trying to delete a prologue or epilogue instruction
1642 that isn't flagged as possibly being dead, something is wrong.
1643 But if we are keeping the stack pointer depressed, we might well
1644 be deleting insns that are used to compute the amount to update
1645 it by, so they are fine. */
1646 if (reload_completed
1647 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1648 && (TYPE_RETURNS_STACK_DEPRESSED
1649 (TREE_TYPE (current_function_decl
))))
1650 && (((HAVE_epilogue
|| HAVE_prologue
)
1651 && prologue_epilogue_contains (insn
))
1652 || (HAVE_sibcall_epilogue
1653 && sibcall_epilogue_contains (insn
)))
1654 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1655 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1657 /* Record sets. Do this even for dead instructions, since they
1658 would have killed the values if they hadn't been deleted. */
1659 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1661 /* CC0 is now known to be dead. Either this insn used it,
1662 in which case it doesn't anymore, or clobbered it,
1663 so the next insn can't use it. */
1666 if (libcall_is_dead
)
1667 prev
= propagate_block_delete_libcall ( insn
, note
);
1671 /* If INSN contains a RETVAL note and is dead, but the libcall
1672 as a whole is not dead, then we want to remove INSN, but
1673 not the whole libcall sequence.
1675 However, we need to also remove the dangling REG_LIBCALL
1676 note so that we do not have mis-matched LIBCALL/RETVAL
1677 notes. In theory we could find a new location for the
1678 REG_RETVAL note, but it hardly seems worth the effort.
1680 NOTE at this point will be the RETVAL note if it exists. */
1686 = find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
1687 remove_note (XEXP (note
, 0), libcall_note
);
1690 /* Similarly if INSN contains a LIBCALL note, remove the
1691 dangling REG_RETVAL note. */
1692 note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
);
1698 = find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
1699 remove_note (XEXP (note
, 0), retval_note
);
1702 /* Now delete INSN. */
1703 propagate_block_delete_insn (insn
);
1709 /* See if this is an increment or decrement that can be merged into
1710 a following memory address. */
1713 rtx x
= single_set (insn
);
1715 /* Does this instruction increment or decrement a register? */
1716 if ((flags
& PROP_AUTOINC
)
1718 && GET_CODE (SET_DEST (x
)) == REG
1719 && (GET_CODE (SET_SRC (x
)) == PLUS
1720 || GET_CODE (SET_SRC (x
)) == MINUS
)
1721 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1722 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1723 /* Ok, look for a following memory ref we can combine with.
1724 If one is found, change the memory ref to a PRE_INC
1725 or PRE_DEC, cancel this insn, and return 1.
1726 Return 0 if nothing has been done. */
1727 && try_pre_increment_1 (pbi
, insn
))
1730 #endif /* AUTO_INC_DEC */
1732 CLEAR_REG_SET (pbi
->new_set
);
1734 /* If this is not the final pass, and this insn is copying the value of
1735 a library call and it's dead, don't scan the insns that perform the
1736 library call, so that the call's arguments are not marked live. */
1737 if (libcall_is_dead
)
1739 /* Record the death of the dest reg. */
1740 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1742 insn
= XEXP (note
, 0);
1743 return PREV_INSN (insn
);
1745 else if (GET_CODE (PATTERN (insn
)) == SET
1746 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1747 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1748 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1749 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1750 /* We have an insn to pop a constant amount off the stack.
1751 (Such insns use PLUS regardless of the direction of the stack,
1752 and any insn to adjust the stack by a constant is always a pop.)
1753 These insns, if not dead stores, have no effect on life, though
1754 they do have an effect on the memory stores we are tracking. */
1755 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1759 /* Any regs live at the time of a call instruction must not go
1760 in a register clobbered by calls. Find all regs now live and
1761 record this for them. */
1763 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1764 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1765 { REG_N_CALLS_CROSSED (i
)++; });
1767 /* Record sets. Do this even for dead instructions, since they
1768 would have killed the values if they hadn't been deleted. */
1769 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1771 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; sibcalls do not
1802 clobber anything that must be preserved at end-of-function,
1803 except for return values. */
1805 sibcall_p
= SIBLING_CALL_P (insn
);
1806 live_at_end
= EXIT_BLOCK_PTR
->global_live_at_start
;
1807 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1808 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
)
1810 && REGNO_REG_SET_P (live_at_end
, i
)
1811 && ! refers_to_regno_p (i
, i
+1,
1812 current_function_return_rtx
,
1815 /* We do not want REG_UNUSED notes for these registers. */
1816 mark_set_1 (pbi
, CLOBBER
, regno_reg_rtx
[i
], cond
, insn
,
1817 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1821 /* If an insn doesn't use CC0, it becomes dead since we assume
1822 that every insn clobbers it. So show it dead here;
1823 mark_used_regs will set it live if it is referenced. */
1828 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1829 if ((flags
& PROP_EQUAL_NOTES
)
1830 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1831 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1832 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1834 /* Sometimes we may have inserted something before INSN (such as a move)
1835 when we make an auto-inc. So ensure we will scan those insns. */
1837 prev
= PREV_INSN (insn
);
1840 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1846 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1847 cond
= COND_EXEC_TEST (PATTERN (insn
));
1849 /* Calls use their arguments, and may clobber memory which
1850 address involves some register. */
1851 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1853 note
= XEXP (note
, 1))
1854 /* We find USE or CLOBBER entities in a FUNCTION_USAGE list: both
1855 of which mark_used_regs knows how to handle. */
1856 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0), cond
, insn
);
1858 /* The stack ptr is used (honorarily) by a CALL insn. */
1859 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1861 /* Calls may also reference any of the global registers,
1862 so they are made live. */
1863 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1865 mark_used_reg (pbi
, regno_reg_rtx
[i
], cond
, insn
);
1869 /* On final pass, update counts of how many insns in which each reg
1871 if (flags
& PROP_REG_INFO
)
1872 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1873 { REG_LIVE_LENGTH (i
)++; });
1878 /* Initialize a propagate_block_info struct for public consumption.
1879 Note that the structure itself is opaque to this file, but that
1880 the user can use the regsets provided here. */
1882 struct propagate_block_info
*
1883 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1885 regset live
, local_set
, cond_local_set
;
1888 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1891 pbi
->reg_live
= live
;
1892 pbi
->mem_set_list
= NULL_RTX
;
1893 pbi
->mem_set_list_len
= 0;
1894 pbi
->local_set
= local_set
;
1895 pbi
->cond_local_set
= cond_local_set
;
1899 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1900 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1902 pbi
->reg_next_use
= NULL
;
1904 pbi
->new_set
= BITMAP_XMALLOC ();
1906 #ifdef HAVE_conditional_execution
1907 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1908 free_reg_cond_life_info
);
1909 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1911 /* If this block ends in a conditional branch, for each register live
1912 from one side of the branch and not the other, record the register
1913 as conditionally dead. */
1914 if (GET_CODE (bb
->end
) == JUMP_INSN
1915 && any_condjump_p (bb
->end
))
1917 regset_head diff_head
;
1918 regset diff
= INITIALIZE_REG_SET (diff_head
);
1919 basic_block bb_true
, bb_false
;
1920 rtx cond_true
, cond_false
, set_src
;
1923 /* Identify the successor blocks. */
1924 bb_true
= bb
->succ
->dest
;
1925 if (bb
->succ
->succ_next
!= NULL
)
1927 bb_false
= bb
->succ
->succ_next
->dest
;
1929 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1931 basic_block t
= bb_false
;
1935 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1940 /* This can happen with a conditional jump to the next insn. */
1941 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1944 /* Simplest way to do nothing. */
1948 /* Extract the condition from the branch. */
1949 set_src
= SET_SRC (pc_set (bb
->end
));
1950 cond_true
= XEXP (set_src
, 0);
1951 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1952 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1953 XEXP (cond_true
, 1));
1954 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1957 cond_false
= cond_true
;
1961 /* Compute which register lead different lives in the successors. */
1962 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1963 bb_false
->global_live_at_start
, BITMAP_XOR
))
1965 rtx reg
= XEXP (cond_true
, 0);
1967 if (GET_CODE (reg
) == SUBREG
)
1968 reg
= SUBREG_REG (reg
);
1970 if (GET_CODE (reg
) != REG
)
1973 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1975 /* For each such register, mark it conditionally dead. */
1976 EXECUTE_IF_SET_IN_REG_SET
1979 struct reg_cond_life_info
*rcli
;
1982 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1984 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1988 rcli
->condition
= cond
;
1989 rcli
->stores
= const0_rtx
;
1990 rcli
->orig_condition
= cond
;
1992 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1993 (splay_tree_value
) rcli
);
1997 FREE_REG_SET (diff
);
2001 /* If this block has no successors, any stores to the frame that aren't
2002 used later in the block are dead. So make a pass over the block
2003 recording any such that are made and show them dead at the end. We do
2004 a very conservative and simple job here. */
2006 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
2007 && (TYPE_RETURNS_STACK_DEPRESSED
2008 (TREE_TYPE (current_function_decl
))))
2009 && (flags
& PROP_SCAN_DEAD_STORES
)
2010 && (bb
->succ
== NULL
2011 || (bb
->succ
->succ_next
== NULL
2012 && bb
->succ
->dest
== EXIT_BLOCK_PTR
2013 && ! current_function_calls_eh_return
)))
2016 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
2017 if (GET_CODE (insn
) == INSN
2018 && (set
= single_set (insn
))
2019 && GET_CODE (SET_DEST (set
)) == MEM
)
2021 rtx mem
= SET_DEST (set
);
2022 rtx canon_mem
= canon_rtx (mem
);
2024 /* This optimization is performed by faking a store to the
2025 memory at the end of the block. This doesn't work for
2026 unchanging memories because multiple stores to unchanging
2027 memory is illegal and alias analysis doesn't consider it. */
2028 if (RTX_UNCHANGING_P (canon_mem
))
2031 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
2032 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
2033 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
2034 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
2035 add_to_mem_set_list (pbi
, canon_mem
);
2042 /* Release a propagate_block_info struct. */
2045 free_propagate_block_info (pbi
)
2046 struct propagate_block_info
*pbi
;
2048 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2050 BITMAP_XFREE (pbi
->new_set
);
2052 #ifdef HAVE_conditional_execution
2053 splay_tree_delete (pbi
->reg_cond_dead
);
2054 BITMAP_XFREE (pbi
->reg_cond_reg
);
2057 if (pbi
->reg_next_use
)
2058 free (pbi
->reg_next_use
);
2063 /* Compute the registers live at the beginning of a basic block BB from
2064 those live at the end.
2066 When called, REG_LIVE contains those live at the end. On return, it
2067 contains those live at the beginning.
2069 LOCAL_SET, if non-null, will be set with all registers killed
2070 unconditionally by this basic block.
2071 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2072 killed conditionally by this basic block. If there is any unconditional
2073 set of a register, then the corresponding bit will be set in LOCAL_SET
2074 and cleared in COND_LOCAL_SET.
2075 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2076 case, the resulting set will be equal to the union of the two sets that
2077 would otherwise be computed.
2079 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2082 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2086 regset cond_local_set
;
2089 struct propagate_block_info
*pbi
;
2093 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2095 if (flags
& PROP_REG_INFO
)
2099 /* Process the regs live at the end of the block.
2100 Mark them as not local to any one basic block. */
2101 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2102 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2105 /* Scan the block an insn at a time from end to beginning. */
2108 for (insn
= bb
->end
;; insn
= prev
)
2110 /* If this is a call to `setjmp' et al, warn if any
2111 non-volatile datum is live. */
2112 if ((flags
& PROP_REG_INFO
)
2113 && GET_CODE (insn
) == CALL_INSN
2114 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2115 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2117 prev
= propagate_one_insn (pbi
, insn
);
2118 changed
|= NEXT_INSN (prev
) != insn
;
2120 if (insn
== bb
->head
)
2124 free_propagate_block_info (pbi
);
2129 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2130 (SET expressions whose destinations are registers dead after the insn).
2131 NEEDED is the regset that says which regs are alive after the insn.
2133 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2135 If X is the entire body of an insn, NOTES contains the reg notes
2136 pertaining to the insn. */
2139 insn_dead_p (pbi
, x
, call_ok
, notes
)
2140 struct propagate_block_info
*pbi
;
2143 rtx notes ATTRIBUTE_UNUSED
;
2145 enum rtx_code code
= GET_CODE (x
);
2147 /* Don't eliminate insns that may trap. */
2148 if (flag_non_call_exceptions
&& may_trap_p (x
))
2152 /* As flow is invoked after combine, we must take existing AUTO_INC
2153 expressions into account. */
2154 for (; notes
; notes
= XEXP (notes
, 1))
2156 if (REG_NOTE_KIND (notes
) == REG_INC
)
2158 int regno
= REGNO (XEXP (notes
, 0));
2160 /* Don't delete insns to set global regs. */
2161 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2162 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2168 /* If setting something that's a reg or part of one,
2169 see if that register's altered value will be live. */
2173 rtx r
= SET_DEST (x
);
2176 if (GET_CODE (r
) == CC0
)
2177 return ! pbi
->cc0_live
;
2180 /* A SET that is a subroutine call cannot be dead. */
2181 if (GET_CODE (SET_SRC (x
)) == CALL
)
2187 /* Don't eliminate loads from volatile memory or volatile asms. */
2188 else if (volatile_refs_p (SET_SRC (x
)))
2191 if (GET_CODE (r
) == MEM
)
2195 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2198 canon_r
= canon_rtx (r
);
2200 /* Walk the set of memory locations we are currently tracking
2201 and see if one is an identical match to this memory location.
2202 If so, this memory write is dead (remember, we're walking
2203 backwards from the end of the block to the start). Since
2204 rtx_equal_p does not check the alias set or flags, we also
2205 must have the potential for them to conflict (anti_dependence). */
2206 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2207 if (anti_dependence (r
, XEXP (temp
, 0)))
2209 rtx mem
= XEXP (temp
, 0);
2211 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2212 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2213 <= GET_MODE_SIZE (GET_MODE (mem
))))
2217 /* Check if memory reference matches an auto increment. Only
2218 post increment/decrement or modify are valid. */
2219 if (GET_MODE (mem
) == GET_MODE (r
)
2220 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2221 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2222 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2223 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2224 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2231 while (GET_CODE (r
) == SUBREG
2232 || GET_CODE (r
) == STRICT_LOW_PART
2233 || GET_CODE (r
) == ZERO_EXTRACT
)
2236 if (GET_CODE (r
) == REG
)
2238 int regno
= REGNO (r
);
2241 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2244 /* If this is a hard register, verify that subsequent
2245 words are not needed. */
2246 if (regno
< FIRST_PSEUDO_REGISTER
)
2248 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2251 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2255 /* Don't delete insns to set global regs. */
2256 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2259 /* Make sure insns to set the stack pointer aren't deleted. */
2260 if (regno
== STACK_POINTER_REGNUM
)
2263 /* ??? These bits might be redundant with the force live bits
2264 in calculate_global_regs_live. We would delete from
2265 sequential sets; whether this actually affects real code
2266 for anything but the stack pointer I don't know. */
2267 /* Make sure insns to set the frame pointer aren't deleted. */
2268 if (regno
== FRAME_POINTER_REGNUM
2269 && (! reload_completed
|| frame_pointer_needed
))
2271 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2272 if (regno
== HARD_FRAME_POINTER_REGNUM
2273 && (! reload_completed
|| frame_pointer_needed
))
2277 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2278 /* Make sure insns to set arg pointer are never deleted
2279 (if the arg pointer isn't fixed, there will be a USE
2280 for it, so we can treat it normally). */
2281 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2285 /* Otherwise, the set is dead. */
2291 /* If performing several activities, insn is dead if each activity
2292 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2293 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2295 else if (code
== PARALLEL
)
2297 int i
= XVECLEN (x
, 0);
2299 for (i
--; i
>= 0; i
--)
2300 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2301 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2302 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2308 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2309 is not necessarily true for hard registers. */
2310 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2311 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2312 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2315 /* We do not check other CLOBBER or USE here. An insn consisting of just
2316 a CLOBBER or just a USE should not be deleted. */
2320 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2321 return 1 if the entire library call is dead.
2322 This is true if INSN copies a register (hard or pseudo)
2323 and if the hard return reg of the call insn is dead.
2324 (The caller should have tested the destination of the SET inside
2325 INSN already for death.)
2327 If this insn doesn't just copy a register, then we don't
2328 have an ordinary libcall. In that case, cse could not have
2329 managed to substitute the source for the dest later on,
2330 so we can assume the libcall is dead.
2332 PBI is the block info giving pseudoregs live before this insn.
2333 NOTE is the REG_RETVAL note of the insn. */
2336 libcall_dead_p (pbi
, note
, insn
)
2337 struct propagate_block_info
*pbi
;
2341 rtx x
= single_set (insn
);
2345 rtx r
= SET_SRC (x
);
2347 if (GET_CODE (r
) == REG
)
2349 rtx call
= XEXP (note
, 0);
2353 /* Find the call insn. */
2354 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2355 call
= NEXT_INSN (call
);
2357 /* If there is none, do nothing special,
2358 since ordinary death handling can understand these insns. */
2362 /* See if the hard reg holding the value is dead.
2363 If this is a PARALLEL, find the call within it. */
2364 call_pat
= PATTERN (call
);
2365 if (GET_CODE (call_pat
) == PARALLEL
)
2367 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2368 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2369 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2372 /* This may be a library call that is returning a value
2373 via invisible pointer. Do nothing special, since
2374 ordinary death handling can understand these insns. */
2378 call_pat
= XVECEXP (call_pat
, 0, i
);
2381 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2387 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2388 live at function entry. Don't count global register variables, variables
2389 in registers that can be used for function arg passing, or variables in
2390 fixed hard registers. */
2393 regno_uninitialized (regno
)
2396 if (n_basic_blocks
== 0
2397 || (regno
< FIRST_PSEUDO_REGISTER
2398 && (global_regs
[regno
]
2399 || fixed_regs
[regno
]
2400 || FUNCTION_ARG_REGNO_P (regno
))))
2403 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->global_live_at_end
, regno
);
2406 /* 1 if register REGNO was alive at a place where `setjmp' was called
2407 and was set more than once or is an argument.
2408 Such regs may be clobbered by `longjmp'. */
2411 regno_clobbered_at_setjmp (regno
)
2414 if (n_basic_blocks
== 0)
2417 return ((REG_N_SETS (regno
) > 1
2418 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->global_live_at_end
, regno
))
2419 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2422 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2423 maximal list size; look for overlaps in mode and select the largest. */
2425 add_to_mem_set_list (pbi
, mem
)
2426 struct propagate_block_info
*pbi
;
2431 /* We don't know how large a BLKmode store is, so we must not
2432 take them into consideration. */
2433 if (GET_MODE (mem
) == BLKmode
)
2436 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2438 rtx e
= XEXP (i
, 0);
2439 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2441 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2444 /* If we must store a copy of the mem, we can just modify
2445 the mode of the stored copy. */
2446 if (pbi
->flags
& PROP_AUTOINC
)
2447 PUT_MODE (e
, GET_MODE (mem
));
2456 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2459 /* Store a copy of mem, otherwise the address may be
2460 scrogged by find_auto_inc. */
2461 if (pbi
->flags
& PROP_AUTOINC
)
2462 mem
= shallow_copy_rtx (mem
);
2464 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2465 pbi
->mem_set_list_len
++;
2469 /* INSN references memory, possibly using autoincrement addressing modes.
2470 Find any entries on the mem_set_list that need to be invalidated due
2471 to an address change. */
2474 invalidate_mems_from_autoinc (px
, data
)
2479 struct propagate_block_info
*pbi
= data
;
2481 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2483 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2490 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2493 invalidate_mems_from_set (pbi
, exp
)
2494 struct propagate_block_info
*pbi
;
2497 rtx temp
= pbi
->mem_set_list
;
2498 rtx prev
= NULL_RTX
;
2503 next
= XEXP (temp
, 1);
2504 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2506 /* Splice this entry out of the list. */
2508 XEXP (prev
, 1) = next
;
2510 pbi
->mem_set_list
= next
;
2511 free_EXPR_LIST_node (temp
);
2512 pbi
->mem_set_list_len
--;
2520 /* Process the registers that are set within X. Their bits are set to
2521 1 in the regset DEAD, because they are dead prior to this insn.
2523 If INSN is nonzero, it is the insn being processed.
2525 FLAGS is the set of operations to perform. */
2528 mark_set_regs (pbi
, x
, insn
)
2529 struct propagate_block_info
*pbi
;
2532 rtx cond
= NULL_RTX
;
2537 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2539 if (REG_NOTE_KIND (link
) == REG_INC
)
2540 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2541 (GET_CODE (x
) == COND_EXEC
2542 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2546 switch (code
= GET_CODE (x
))
2550 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2554 cond
= COND_EXEC_TEST (x
);
2555 x
= COND_EXEC_CODE (x
);
2562 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2564 rtx sub
= XVECEXP (x
, 0, i
);
2565 switch (code
= GET_CODE (sub
))
2568 if (cond
!= NULL_RTX
)
2571 cond
= COND_EXEC_TEST (sub
);
2572 sub
= COND_EXEC_CODE (sub
);
2573 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2579 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2594 /* Process a single set, which appears in INSN. REG (which may not
2595 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2596 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2597 If the set is conditional (because it appear in a COND_EXEC), COND
2598 will be the condition. */
2601 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2602 struct propagate_block_info
*pbi
;
2604 rtx reg
, cond
, insn
;
2607 int regno_first
= -1, regno_last
= -1;
2608 unsigned long not_dead
= 0;
2611 /* Modifying just one hardware register of a multi-reg value or just a
2612 byte field of a register does not mean the value from before this insn
2613 is now dead. Of course, if it was dead after it's unused now. */
2615 switch (GET_CODE (reg
))
2618 /* Some targets place small structures in registers for return values of
2619 functions. We have to detect this case specially here to get correct
2620 flow information. */
2621 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2622 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2623 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2629 case STRICT_LOW_PART
:
2630 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2632 reg
= XEXP (reg
, 0);
2633 while (GET_CODE (reg
) == SUBREG
2634 || GET_CODE (reg
) == ZERO_EXTRACT
2635 || GET_CODE (reg
) == SIGN_EXTRACT
2636 || GET_CODE (reg
) == STRICT_LOW_PART
);
2637 if (GET_CODE (reg
) == MEM
)
2639 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2643 regno_last
= regno_first
= REGNO (reg
);
2644 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2645 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2649 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2651 enum machine_mode outer_mode
= GET_MODE (reg
);
2652 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2654 /* Identify the range of registers affected. This is moderately
2655 tricky for hard registers. See alter_subreg. */
2657 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2658 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2660 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2663 regno_last
= (regno_first
2664 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2666 /* Since we've just adjusted the register number ranges, make
2667 sure REG matches. Otherwise some_was_live will be clear
2668 when it shouldn't have been, and we'll create incorrect
2669 REG_UNUSED notes. */
2670 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2674 /* If the number of words in the subreg is less than the number
2675 of words in the full register, we have a well-defined partial
2676 set. Otherwise the high bits are undefined.
2678 This is only really applicable to pseudos, since we just took
2679 care of multi-word hard registers. */
2680 if (((GET_MODE_SIZE (outer_mode
)
2681 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2682 < ((GET_MODE_SIZE (inner_mode
)
2683 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2684 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2687 reg
= SUBREG_REG (reg
);
2691 reg
= SUBREG_REG (reg
);
2698 /* If this set is a MEM, then it kills any aliased writes.
2699 If this set is a REG, then it kills any MEMs which use the reg. */
2700 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
2702 if (GET_CODE (reg
) == REG
)
2703 invalidate_mems_from_set (pbi
, reg
);
2705 /* If the memory reference had embedded side effects (autoincrement
2706 address modes. Then we may need to kill some entries on the
2708 if (insn
&& GET_CODE (reg
) == MEM
)
2709 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2711 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2712 /* ??? With more effort we could track conditional memory life. */
2714 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2717 if (GET_CODE (reg
) == REG
2718 && ! (regno_first
== FRAME_POINTER_REGNUM
2719 && (! reload_completed
|| frame_pointer_needed
))
2720 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2721 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2722 && (! reload_completed
|| frame_pointer_needed
))
2724 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2725 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2729 int some_was_live
= 0, some_was_dead
= 0;
2731 for (i
= regno_first
; i
<= regno_last
; ++i
)
2733 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2736 /* Order of the set operation matters here since both
2737 sets may be the same. */
2738 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2739 if (cond
!= NULL_RTX
2740 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2741 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2743 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2745 if (code
!= CLOBBER
)
2746 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2748 some_was_live
|= needed_regno
;
2749 some_was_dead
|= ! needed_regno
;
2752 #ifdef HAVE_conditional_execution
2753 /* Consider conditional death in deciding that the register needs
2755 if (some_was_live
&& ! not_dead
2756 /* The stack pointer is never dead. Well, not strictly true,
2757 but it's very difficult to tell from here. Hopefully
2758 combine_stack_adjustments will fix up the most egregious
2760 && regno_first
!= STACK_POINTER_REGNUM
)
2762 for (i
= regno_first
; i
<= regno_last
; ++i
)
2763 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2764 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2768 /* Additional data to record if this is the final pass. */
2769 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2770 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2773 int blocknum
= pbi
->bb
->index
;
2776 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2778 y
= pbi
->reg_next_use
[regno_first
];
2780 /* The next use is no longer next, since a store intervenes. */
2781 for (i
= regno_first
; i
<= regno_last
; ++i
)
2782 pbi
->reg_next_use
[i
] = 0;
2785 if (flags
& PROP_REG_INFO
)
2787 for (i
= regno_first
; i
<= regno_last
; ++i
)
2789 /* Count (weighted) references, stores, etc. This counts a
2790 register twice if it is modified, but that is correct. */
2791 REG_N_SETS (i
) += 1;
2792 REG_N_REFS (i
) += 1;
2793 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2795 /* The insns where a reg is live are normally counted
2796 elsewhere, but we want the count to include the insn
2797 where the reg is set, and the normal counting mechanism
2798 would not count it. */
2799 REG_LIVE_LENGTH (i
) += 1;
2802 /* If this is a hard reg, record this function uses the reg. */
2803 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2805 for (i
= regno_first
; i
<= regno_last
; i
++)
2806 regs_ever_live
[i
] = 1;
2810 /* Keep track of which basic blocks each reg appears in. */
2811 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2812 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2813 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2814 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2818 if (! some_was_dead
)
2820 if (flags
& PROP_LOG_LINKS
)
2822 /* Make a logical link from the next following insn
2823 that uses this register, back to this insn.
2824 The following insns have already been processed.
2826 We don't build a LOG_LINK for hard registers containing
2827 in ASM_OPERANDs. If these registers get replaced,
2828 we might wind up changing the semantics of the insn,
2829 even if reload can make what appear to be valid
2830 assignments later. */
2831 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2832 && (regno_first
>= FIRST_PSEUDO_REGISTER
2833 || asm_noperands (PATTERN (y
)) < 0))
2834 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2839 else if (! some_was_live
)
2841 if (flags
& PROP_REG_INFO
)
2842 REG_N_DEATHS (regno_first
) += 1;
2844 if (flags
& PROP_DEATH_NOTES
)
2846 /* Note that dead stores have already been deleted
2847 when possible. If we get here, we have found a
2848 dead store that cannot be eliminated (because the
2849 same insn does something useful). Indicate this
2850 by marking the reg being set as dying here. */
2852 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2857 if (flags
& PROP_DEATH_NOTES
)
2859 /* This is a case where we have a multi-word hard register
2860 and some, but not all, of the words of the register are
2861 needed in subsequent insns. Write REG_UNUSED notes
2862 for those parts that were not needed. This case should
2865 for (i
= regno_first
; i
<= regno_last
; ++i
)
2866 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2868 = alloc_EXPR_LIST (REG_UNUSED
,
2875 /* Mark the register as being dead. */
2877 /* The stack pointer is never dead. Well, not strictly true,
2878 but it's very difficult to tell from here. Hopefully
2879 combine_stack_adjustments will fix up the most egregious
2881 && regno_first
!= STACK_POINTER_REGNUM
)
2883 for (i
= regno_first
; i
<= regno_last
; ++i
)
2884 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2885 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2888 else if (GET_CODE (reg
) == REG
)
2890 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2891 pbi
->reg_next_use
[regno_first
] = 0;
2894 /* If this is the last pass and this is a SCRATCH, show it will be dying
2895 here and count it. */
2896 else if (GET_CODE (reg
) == SCRATCH
)
2898 if (flags
& PROP_DEATH_NOTES
)
2900 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2904 #ifdef HAVE_conditional_execution
2905 /* Mark REGNO conditionally dead.
2906 Return true if the register is now unconditionally dead. */
2909 mark_regno_cond_dead (pbi
, regno
, cond
)
2910 struct propagate_block_info
*pbi
;
2914 /* If this is a store to a predicate register, the value of the
2915 predicate is changing, we don't know that the predicate as seen
2916 before is the same as that seen after. Flush all dependent
2917 conditions from reg_cond_dead. This will make all such
2918 conditionally live registers unconditionally live. */
2919 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2920 flush_reg_cond_reg (pbi
, regno
);
2922 /* If this is an unconditional store, remove any conditional
2923 life that may have existed. */
2924 if (cond
== NULL_RTX
)
2925 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2928 splay_tree_node node
;
2929 struct reg_cond_life_info
*rcli
;
2932 /* Otherwise this is a conditional set. Record that fact.
2933 It may have been conditionally used, or there may be a
2934 subsequent set with a complimentary condition. */
2936 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2939 /* The register was unconditionally live previously.
2940 Record the current condition as the condition under
2941 which it is dead. */
2942 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2943 rcli
->condition
= cond
;
2944 rcli
->stores
= cond
;
2945 rcli
->orig_condition
= const0_rtx
;
2946 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2947 (splay_tree_value
) rcli
);
2949 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2951 /* Not unconditionally dead. */
2956 /* The register was conditionally live previously.
2957 Add the new condition to the old. */
2958 rcli
= (struct reg_cond_life_info
*) node
->value
;
2959 ncond
= rcli
->condition
;
2960 ncond
= ior_reg_cond (ncond
, cond
, 1);
2961 if (rcli
->stores
== const0_rtx
)
2962 rcli
->stores
= cond
;
2963 else if (rcli
->stores
!= const1_rtx
)
2964 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2966 /* If the register is now unconditionally dead, remove the entry
2967 in the splay_tree. A register is unconditionally dead if the
2968 dead condition ncond is true. A register is also unconditionally
2969 dead if the sum of all conditional stores is an unconditional
2970 store (stores is true), and the dead condition is identically the
2971 same as the original dead condition initialized at the end of
2972 the block. This is a pointer compare, not an rtx_equal_p
2974 if (ncond
== const1_rtx
2975 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2976 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2979 rcli
->condition
= ncond
;
2981 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2983 /* Not unconditionally dead. */
2992 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2995 free_reg_cond_life_info (value
)
2996 splay_tree_value value
;
2998 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
3002 /* Helper function for flush_reg_cond_reg. */
3005 flush_reg_cond_reg_1 (node
, data
)
3006 splay_tree_node node
;
3009 struct reg_cond_life_info
*rcli
;
3010 int *xdata
= (int *) data
;
3011 unsigned int regno
= xdata
[0];
3013 /* Don't need to search if last flushed value was farther on in
3014 the in-order traversal. */
3015 if (xdata
[1] >= (int) node
->key
)
3018 /* Splice out portions of the expression that refer to regno. */
3019 rcli
= (struct reg_cond_life_info
*) node
->value
;
3020 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
3021 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
3022 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
3024 /* If the entire condition is now false, signal the node to be removed. */
3025 if (rcli
->condition
== const0_rtx
)
3027 xdata
[1] = node
->key
;
3030 else if (rcli
->condition
== const1_rtx
)
3036 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3039 flush_reg_cond_reg (pbi
, regno
)
3040 struct propagate_block_info
*pbi
;
3047 while (splay_tree_foreach (pbi
->reg_cond_dead
,
3048 flush_reg_cond_reg_1
, pair
) == -1)
3049 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3051 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3054 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3055 For ior/and, the ADD flag determines whether we want to add the new
3056 condition X to the old one unconditionally. If it is zero, we will
3057 only return a new expression if X allows us to simplify part of
3058 OLD, otherwise we return NULL to the caller.
3059 If ADD is nonzero, we will return a new condition in all cases. The
3060 toplevel caller of one of these functions should always pass 1 for
3064 ior_reg_cond (old
, x
, add
)
3070 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3072 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3073 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3074 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3076 if (GET_CODE (x
) == GET_CODE (old
)
3077 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3081 return gen_rtx_IOR (0, old
, x
);
3084 switch (GET_CODE (old
))
3087 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3088 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3089 if (op0
!= NULL
|| op1
!= NULL
)
3091 if (op0
== const0_rtx
)
3092 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3093 if (op1
== const0_rtx
)
3094 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3095 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3098 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3099 else if (rtx_equal_p (x
, op0
))
3100 /* (x | A) | x ~ (x | A). */
3103 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3104 else if (rtx_equal_p (x
, op1
))
3105 /* (A | x) | x ~ (A | x). */
3107 return gen_rtx_IOR (0, op0
, op1
);
3111 return gen_rtx_IOR (0, old
, x
);
3114 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3115 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3116 if (op0
!= NULL
|| op1
!= NULL
)
3118 if (op0
== const1_rtx
)
3119 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3120 if (op1
== const1_rtx
)
3121 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3122 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3125 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3126 else if (rtx_equal_p (x
, op0
))
3127 /* (x & A) | x ~ x. */
3130 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3131 else if (rtx_equal_p (x
, op1
))
3132 /* (A & x) | x ~ x. */
3134 return gen_rtx_AND (0, op0
, op1
);
3138 return gen_rtx_IOR (0, old
, x
);
3141 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3143 return not_reg_cond (op0
);
3146 return gen_rtx_IOR (0, old
, x
);
3157 enum rtx_code x_code
;
3159 if (x
== const0_rtx
)
3161 else if (x
== const1_rtx
)
3163 x_code
= GET_CODE (x
);
3166 if (GET_RTX_CLASS (x_code
) == '<'
3167 && GET_CODE (XEXP (x
, 0)) == REG
)
3169 if (XEXP (x
, 1) != const0_rtx
)
3172 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3173 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3175 return gen_rtx_NOT (0, x
);
3179 and_reg_cond (old
, x
, add
)
3185 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3187 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3188 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3189 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3191 if (GET_CODE (x
) == GET_CODE (old
)
3192 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3196 return gen_rtx_AND (0, old
, x
);
3199 switch (GET_CODE (old
))
3202 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3203 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3204 if (op0
!= NULL
|| op1
!= NULL
)
3206 if (op0
== const0_rtx
)
3207 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3208 if (op1
== const0_rtx
)
3209 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3210 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3213 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3214 else if (rtx_equal_p (x
, op0
))
3215 /* (x | A) & x ~ x. */
3218 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3219 else if (rtx_equal_p (x
, op1
))
3220 /* (A | x) & x ~ x. */
3222 return gen_rtx_IOR (0, op0
, op1
);
3226 return gen_rtx_AND (0, old
, x
);
3229 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3230 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3231 if (op0
!= NULL
|| op1
!= NULL
)
3233 if (op0
== const1_rtx
)
3234 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3235 if (op1
== const1_rtx
)
3236 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3237 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3240 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3241 else if (rtx_equal_p (x
, op0
))
3242 /* (x & A) & x ~ (x & A). */
3245 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3246 else if (rtx_equal_p (x
, op1
))
3247 /* (A & x) & x ~ (A & x). */
3249 return gen_rtx_AND (0, op0
, op1
);
3253 return gen_rtx_AND (0, old
, x
);
3256 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3258 return not_reg_cond (op0
);
3261 return gen_rtx_AND (0, old
, x
);
3268 /* Given a condition X, remove references to reg REGNO and return the
3269 new condition. The removal will be done so that all conditions
3270 involving REGNO are considered to evaluate to false. This function
3271 is used when the value of REGNO changes. */
3274 elim_reg_cond (x
, regno
)
3280 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3282 if (REGNO (XEXP (x
, 0)) == regno
)
3287 switch (GET_CODE (x
))
3290 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3291 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3292 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3294 if (op0
== const1_rtx
)
3296 if (op1
== const1_rtx
)
3298 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3300 return gen_rtx_AND (0, op0
, op1
);
3303 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3304 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3305 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3307 if (op0
== const0_rtx
)
3309 if (op1
== const0_rtx
)
3311 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3313 return gen_rtx_IOR (0, op0
, op1
);
3316 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3317 if (op0
== const0_rtx
)
3319 if (op0
== const1_rtx
)
3321 if (op0
!= XEXP (x
, 0))
3322 return not_reg_cond (op0
);
3329 #endif /* HAVE_conditional_execution */
3333 /* Try to substitute the auto-inc expression INC as the address inside
3334 MEM which occurs in INSN. Currently, the address of MEM is an expression
3335 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3336 that has a single set whose source is a PLUS of INCR_REG and something
3340 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3341 struct propagate_block_info
*pbi
;
3342 rtx inc
, insn
, mem
, incr
, incr_reg
;
3344 int regno
= REGNO (incr_reg
);
3345 rtx set
= single_set (incr
);
3346 rtx q
= SET_DEST (set
);
3347 rtx y
= SET_SRC (set
);
3348 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3350 /* Make sure this reg appears only once in this insn. */
3351 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3354 if (dead_or_set_p (incr
, incr_reg
)
3355 /* Mustn't autoinc an eliminable register. */
3356 && (regno
>= FIRST_PSEUDO_REGISTER
3357 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3359 /* This is the simple case. Try to make the auto-inc. If
3360 we can't, we are done. Otherwise, we will do any
3361 needed updates below. */
3362 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3365 else if (GET_CODE (q
) == REG
3366 /* PREV_INSN used here to check the semi-open interval
3368 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3369 /* We must also check for sets of q as q may be
3370 a call clobbered hard register and there may
3371 be a call between PREV_INSN (insn) and incr. */
3372 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3374 /* We have *p followed sometime later by q = p+size.
3375 Both p and q must be live afterward,
3376 and q is not used between INSN and its assignment.
3377 Change it to q = p, ...*q..., q = q+size.
3378 Then fall into the usual case. */
3382 emit_move_insn (q
, incr_reg
);
3383 insns
= get_insns ();
3386 /* If we can't make the auto-inc, or can't make the
3387 replacement into Y, exit. There's no point in making
3388 the change below if we can't do the auto-inc and doing
3389 so is not correct in the pre-inc case. */
3392 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3393 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3394 if (! apply_change_group ())
3397 /* We now know we'll be doing this change, so emit the
3398 new insn(s) and do the updates. */
3399 emit_insn_before (insns
, insn
);
3401 if (pbi
->bb
->head
== insn
)
3402 pbi
->bb
->head
= insns
;
3404 /* INCR will become a NOTE and INSN won't contain a
3405 use of INCR_REG. If a use of INCR_REG was just placed in
3406 the insn before INSN, make that the next use.
3407 Otherwise, invalidate it. */
3408 if (GET_CODE (PREV_INSN (insn
)) == INSN
3409 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3410 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3411 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3413 pbi
->reg_next_use
[regno
] = 0;
3418 /* REGNO is now used in INCR which is below INSN, but
3419 it previously wasn't live here. If we don't mark
3420 it as live, we'll put a REG_DEAD note for it
3421 on this insn, which is incorrect. */
3422 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3424 /* If there are any calls between INSN and INCR, show
3425 that REGNO now crosses them. */
3426 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3427 if (GET_CODE (temp
) == CALL_INSN
)
3428 REG_N_CALLS_CROSSED (regno
)++;
3430 /* Invalidate alias info for Q since we just changed its value. */
3431 clear_reg_alias_info (q
);
3436 /* If we haven't returned, it means we were able to make the
3437 auto-inc, so update the status. First, record that this insn
3438 has an implicit side effect. */
3440 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3442 /* Modify the old increment-insn to simply copy
3443 the already-incremented value of our register. */
3444 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3447 /* If that makes it a no-op (copying the register into itself) delete
3448 it so it won't appear to be a "use" and a "set" of this
3450 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3452 /* If the original source was dead, it's dead now. */
3455 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3457 remove_note (incr
, note
);
3458 if (XEXP (note
, 0) != incr_reg
)
3459 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3462 PUT_CODE (incr
, NOTE
);
3463 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3464 NOTE_SOURCE_FILE (incr
) = 0;
3467 if (regno
>= FIRST_PSEUDO_REGISTER
)
3469 /* Count an extra reference to the reg. When a reg is
3470 incremented, spilling it is worse, so we want to make
3471 that less likely. */
3472 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3474 /* Count the increment as a setting of the register,
3475 even though it isn't a SET in rtl. */
3476 REG_N_SETS (regno
)++;
3480 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3484 find_auto_inc (pbi
, x
, insn
)
3485 struct propagate_block_info
*pbi
;
3489 rtx addr
= XEXP (x
, 0);
3490 HOST_WIDE_INT offset
= 0;
3491 rtx set
, y
, incr
, inc_val
;
3493 int size
= GET_MODE_SIZE (GET_MODE (x
));
3495 if (GET_CODE (insn
) == JUMP_INSN
)
3498 /* Here we detect use of an index register which might be good for
3499 postincrement, postdecrement, preincrement, or predecrement. */
3501 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3502 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3504 if (GET_CODE (addr
) != REG
)
3507 regno
= REGNO (addr
);
3509 /* Is the next use an increment that might make auto-increment? */
3510 incr
= pbi
->reg_next_use
[regno
];
3511 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3513 set
= single_set (incr
);
3514 if (set
== 0 || GET_CODE (set
) != SET
)
3518 if (GET_CODE (y
) != PLUS
)
3521 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3522 inc_val
= XEXP (y
, 1);
3523 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3524 inc_val
= XEXP (y
, 0);
3528 if (GET_CODE (inc_val
) == CONST_INT
)
3530 if (HAVE_POST_INCREMENT
3531 && (INTVAL (inc_val
) == size
&& offset
== 0))
3532 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3534 else if (HAVE_POST_DECREMENT
3535 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3536 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3538 else if (HAVE_PRE_INCREMENT
3539 && (INTVAL (inc_val
) == size
&& offset
== size
))
3540 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3542 else if (HAVE_PRE_DECREMENT
3543 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3544 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3546 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3547 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3548 gen_rtx_PLUS (Pmode
,
3551 insn
, x
, incr
, addr
);
3552 else if (HAVE_PRE_MODIFY_DISP
&& offset
== INTVAL (inc_val
))
3553 attempt_auto_inc (pbi
, gen_rtx_PRE_MODIFY (Pmode
, addr
,
3554 gen_rtx_PLUS (Pmode
,
3557 insn
, x
, incr
, addr
);
3559 else if (GET_CODE (inc_val
) == REG
3560 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3564 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3565 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3566 gen_rtx_PLUS (Pmode
,
3569 insn
, x
, incr
, addr
);
3573 #endif /* AUTO_INC_DEC */
3576 mark_used_reg (pbi
, reg
, cond
, insn
)
3577 struct propagate_block_info
*pbi
;
3579 rtx cond ATTRIBUTE_UNUSED
;
3582 unsigned int regno_first
, regno_last
, i
;
3583 int some_was_live
, some_was_dead
, some_not_set
;
3585 regno_last
= regno_first
= REGNO (reg
);
3586 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3587 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3589 /* Find out if any of this register is live after this instruction. */
3590 some_was_live
= some_was_dead
= 0;
3591 for (i
= regno_first
; i
<= regno_last
; ++i
)
3593 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3594 some_was_live
|= needed_regno
;
3595 some_was_dead
|= ! needed_regno
;
3598 /* Find out if any of the register was set this insn. */
3600 for (i
= regno_first
; i
<= regno_last
; ++i
)
3601 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3603 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3605 /* Record where each reg is used, so when the reg is set we know
3606 the next insn that uses it. */
3607 pbi
->reg_next_use
[regno_first
] = insn
;
3610 if (pbi
->flags
& PROP_REG_INFO
)
3612 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3614 /* If this is a register we are going to try to eliminate,
3615 don't mark it live here. If we are successful in
3616 eliminating it, it need not be live unless it is used for
3617 pseudos, in which case it will have been set live when it
3618 was allocated to the pseudos. If the register will not
3619 be eliminated, reload will set it live at that point.
3621 Otherwise, record that this function uses this register. */
3622 /* ??? The PPC backend tries to "eliminate" on the pic
3623 register to itself. This should be fixed. In the mean
3624 time, hack around it. */
3626 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3627 && (regno_first
== FRAME_POINTER_REGNUM
3628 || regno_first
== ARG_POINTER_REGNUM
)))
3629 for (i
= regno_first
; i
<= regno_last
; ++i
)
3630 regs_ever_live
[i
] = 1;
3634 /* Keep track of which basic block each reg appears in. */
3636 int blocknum
= pbi
->bb
->index
;
3637 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3638 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3639 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3640 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3642 /* Count (weighted) number of uses of each reg. */
3643 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3644 REG_N_REFS (regno_first
)++;
3648 /* Record and count the insns in which a reg dies. If it is used in
3649 this insn and was dead below the insn then it dies in this insn.
3650 If it was set in this insn, we do not make a REG_DEAD note;
3651 likewise if we already made such a note. */
3652 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3656 /* Check for the case where the register dying partially
3657 overlaps the register set by this insn. */
3658 if (regno_first
!= regno_last
)
3659 for (i
= regno_first
; i
<= regno_last
; ++i
)
3660 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3662 /* If none of the words in X is needed, make a REG_DEAD note.
3663 Otherwise, we must make partial REG_DEAD notes. */
3664 if (! some_was_live
)
3666 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3667 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3669 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3671 if (pbi
->flags
& PROP_REG_INFO
)
3672 REG_N_DEATHS (regno_first
)++;
3676 /* Don't make a REG_DEAD note for a part of a register
3677 that is set in the insn. */
3678 for (i
= regno_first
; i
<= regno_last
; ++i
)
3679 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3680 && ! dead_or_set_regno_p (insn
, i
))
3682 = alloc_EXPR_LIST (REG_DEAD
,
3688 /* Mark the register as being live. */
3689 for (i
= regno_first
; i
<= regno_last
; ++i
)
3691 #ifdef HAVE_conditional_execution
3692 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3695 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3697 #ifdef HAVE_conditional_execution
3698 /* If this is a conditional use, record that fact. If it is later
3699 conditionally set, we'll know to kill the register. */
3700 if (cond
!= NULL_RTX
)
3702 splay_tree_node node
;
3703 struct reg_cond_life_info
*rcli
;
3708 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3711 /* The register was unconditionally live previously.
3712 No need to do anything. */
3716 /* The register was conditionally live previously.
3717 Subtract the new life cond from the old death cond. */
3718 rcli
= (struct reg_cond_life_info
*) node
->value
;
3719 ncond
= rcli
->condition
;
3720 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3722 /* If the register is now unconditionally live,
3723 remove the entry in the splay_tree. */
3724 if (ncond
== const0_rtx
)
3725 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3728 rcli
->condition
= ncond
;
3729 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3730 REGNO (XEXP (cond
, 0)));
3736 /* The register was not previously live at all. Record
3737 the condition under which it is still dead. */
3738 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3739 rcli
->condition
= not_reg_cond (cond
);
3740 rcli
->stores
= const0_rtx
;
3741 rcli
->orig_condition
= const0_rtx
;
3742 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3743 (splay_tree_value
) rcli
);
3745 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3748 else if (this_was_live
)
3750 /* The register may have been conditionally live previously, but
3751 is now unconditionally live. Remove it from the conditionally
3752 dead list, so that a conditional set won't cause us to think
3754 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3760 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3761 This is done assuming the registers needed from X are those that
3762 have 1-bits in PBI->REG_LIVE.
3764 INSN is the containing instruction. If INSN is dead, this function
3768 mark_used_regs (pbi
, x
, cond
, insn
)
3769 struct propagate_block_info
*pbi
;
3774 int flags
= pbi
->flags
;
3779 code
= GET_CODE (x
);
3800 /* If we are clobbering a MEM, mark any registers inside the address
3802 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3803 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3807 /* Don't bother watching stores to mems if this is not the
3808 final pass. We'll not be deleting dead stores this round. */
3809 if (optimize
&& (flags
& PROP_SCAN_DEAD_STORES
))
3811 /* Invalidate the data for the last MEM stored, but only if MEM is
3812 something that can be stored into. */
3813 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3814 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3815 /* Needn't clear the memory set list. */
3819 rtx temp
= pbi
->mem_set_list
;
3820 rtx prev
= NULL_RTX
;
3825 next
= XEXP (temp
, 1);
3826 if (anti_dependence (XEXP (temp
, 0), x
))
3828 /* Splice temp out of the list. */
3830 XEXP (prev
, 1) = next
;
3832 pbi
->mem_set_list
= next
;
3833 free_EXPR_LIST_node (temp
);
3834 pbi
->mem_set_list_len
--;
3842 /* If the memory reference had embedded side effects (autoincrement
3843 address modes. Then we may need to kill some entries on the
3846 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3850 if (flags
& PROP_AUTOINC
)
3851 find_auto_inc (pbi
, x
, insn
);
3856 #ifdef CANNOT_CHANGE_MODE_CLASS
3857 if ((flags
& PROP_REG_INFO
)
3858 && GET_CODE (SUBREG_REG (x
)) == REG
3859 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
)
3860 bitmap_set_bit (&subregs_of_mode
, REGNO (SUBREG_REG (x
))
3865 /* While we're here, optimize this case. */
3867 if (GET_CODE (x
) != REG
)
3872 /* See a register other than being set => mark it as needed. */
3873 mark_used_reg (pbi
, x
, cond
, insn
);
3878 rtx testreg
= SET_DEST (x
);
3881 /* If storing into MEM, don't show it as being used. But do
3882 show the address as being used. */
3883 if (GET_CODE (testreg
) == MEM
)
3886 if (flags
& PROP_AUTOINC
)
3887 find_auto_inc (pbi
, testreg
, insn
);
3889 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3890 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3894 /* Storing in STRICT_LOW_PART is like storing in a reg
3895 in that this SET might be dead, so ignore it in TESTREG.
3896 but in some other ways it is like using the reg.
3898 Storing in a SUBREG or a bit field is like storing the entire
3899 register in that if the register's value is not used
3900 then this SET is not needed. */
3901 while (GET_CODE (testreg
) == STRICT_LOW_PART
3902 || GET_CODE (testreg
) == ZERO_EXTRACT
3903 || GET_CODE (testreg
) == SIGN_EXTRACT
3904 || GET_CODE (testreg
) == SUBREG
)
3906 #ifdef CANNOT_CHANGE_MODE_CLASS
3907 if ((flags
& PROP_REG_INFO
)
3908 && GET_CODE (testreg
) == SUBREG
3909 && GET_CODE (SUBREG_REG (testreg
)) == REG
3910 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
)
3911 bitmap_set_bit (&subregs_of_mode
, REGNO (SUBREG_REG (testreg
))
3913 + GET_MODE (testreg
));
3916 /* Modifying a single register in an alternate mode
3917 does not use any of the old value. But these other
3918 ways of storing in a register do use the old value. */
3919 if (GET_CODE (testreg
) == SUBREG
3920 && !((REG_BYTES (SUBREG_REG (testreg
))
3921 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3922 > (REG_BYTES (testreg
)
3923 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3928 testreg
= XEXP (testreg
, 0);
3931 /* If this is a store into a register or group of registers,
3932 recursively scan the value being stored. */
3934 if ((GET_CODE (testreg
) == PARALLEL
3935 && GET_MODE (testreg
) == BLKmode
)
3936 || (GET_CODE (testreg
) == REG
3937 && (regno
= REGNO (testreg
),
3938 ! (regno
== FRAME_POINTER_REGNUM
3939 && (! reload_completed
|| frame_pointer_needed
)))
3940 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3941 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3942 && (! reload_completed
|| frame_pointer_needed
))
3944 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3945 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3950 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3951 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3958 case UNSPEC_VOLATILE
:
3962 /* Traditional and volatile asm instructions must be considered to use
3963 and clobber all hard registers, all pseudo-registers and all of
3964 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3966 Consider for instance a volatile asm that changes the fpu rounding
3967 mode. An insn should not be moved across this even if it only uses
3968 pseudo-regs because it might give an incorrectly rounded result.
3970 ?!? Unfortunately, marking all hard registers as live causes massive
3971 problems for the register allocator and marking all pseudos as live
3972 creates mountains of uninitialized variable warnings.
3974 So for now, just clear the memory set list and mark any regs
3975 we can find in ASM_OPERANDS as used. */
3976 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3978 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3979 pbi
->mem_set_list_len
= 0;
3982 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3983 We can not just fall through here since then we would be confused
3984 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3985 traditional asms unlike their normal usage. */
3986 if (code
== ASM_OPERANDS
)
3990 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3991 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3997 if (cond
!= NULL_RTX
)
4000 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
4002 cond
= COND_EXEC_TEST (x
);
4003 x
= COND_EXEC_CODE (x
);
4007 /* We _do_not_ want to scan operands of phi nodes. Operands of
4008 a phi function are evaluated only when control reaches this
4009 block along a particular edge. Therefore, regs that appear
4010 as arguments to phi should not be added to the global live at
4018 /* Recursively scan the operands of this expression. */
4021 const char * const fmt
= GET_RTX_FORMAT (code
);
4024 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4028 /* Tail recursive case: save a function call level. */
4034 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
4036 else if (fmt
[i
] == 'E')
4039 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4040 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
4049 try_pre_increment_1 (pbi
, insn
)
4050 struct propagate_block_info
*pbi
;
4053 /* Find the next use of this reg. If in same basic block,
4054 make it do pre-increment or pre-decrement if appropriate. */
4055 rtx x
= single_set (insn
);
4056 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
4057 * INTVAL (XEXP (SET_SRC (x
), 1)));
4058 int regno
= REGNO (SET_DEST (x
));
4059 rtx y
= pbi
->reg_next_use
[regno
];
4061 && SET_DEST (x
) != stack_pointer_rtx
4062 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4063 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4064 mode would be better. */
4065 && ! dead_or_set_p (y
, SET_DEST (x
))
4066 && try_pre_increment (y
, SET_DEST (x
), amount
))
4068 /* We have found a suitable auto-increment and already changed
4069 insn Y to do it. So flush this increment instruction. */
4070 propagate_block_delete_insn (insn
);
4072 /* Count a reference to this reg for the increment insn we are
4073 deleting. When a reg is incremented, spilling it is worse,
4074 so we want to make that less likely. */
4075 if (regno
>= FIRST_PSEUDO_REGISTER
)
4077 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4078 REG_N_SETS (regno
)++;
4081 /* Flush any remembered memories depending on the value of
4082 the incremented register. */
4083 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4090 /* Try to change INSN so that it does pre-increment or pre-decrement
4091 addressing on register REG in order to add AMOUNT to REG.
4092 AMOUNT is negative for pre-decrement.
4093 Returns 1 if the change could be made.
4094 This checks all about the validity of the result of modifying INSN. */
4097 try_pre_increment (insn
, reg
, amount
)
4099 HOST_WIDE_INT amount
;
4103 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4104 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4106 /* Nonzero if we can try to make a post-increment or post-decrement.
4107 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4108 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4109 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4112 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4115 /* From the sign of increment, see which possibilities are conceivable
4116 on this target machine. */
4117 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4119 if (HAVE_POST_INCREMENT
&& amount
> 0)
4122 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4124 if (HAVE_POST_DECREMENT
&& amount
< 0)
4127 if (! (pre_ok
|| post_ok
))
4130 /* It is not safe to add a side effect to a jump insn
4131 because if the incremented register is spilled and must be reloaded
4132 there would be no way to store the incremented value back in memory. */
4134 if (GET_CODE (insn
) == JUMP_INSN
)
4139 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4140 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4142 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4146 if (use
== 0 || use
== (rtx
) (size_t) 1)
4149 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4152 /* See if this combination of instruction and addressing mode exists. */
4153 if (! validate_change (insn
, &XEXP (use
, 0),
4154 gen_rtx_fmt_e (amount
> 0
4155 ? (do_post
? POST_INC
: PRE_INC
)
4156 : (do_post
? POST_DEC
: PRE_DEC
),
4160 /* Record that this insn now has an implicit side effect on X. */
4161 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4165 #endif /* AUTO_INC_DEC */
4167 /* Find the place in the rtx X where REG is used as a memory address.
4168 Return the MEM rtx that so uses it.
4169 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4170 (plus REG (const_int PLUSCONST)).
4172 If such an address does not appear, return 0.
4173 If REG appears more than once, or is used other than in such an address,
4177 find_use_as_address (x
, reg
, plusconst
)
4180 HOST_WIDE_INT plusconst
;
4182 enum rtx_code code
= GET_CODE (x
);
4183 const char * const fmt
= GET_RTX_FORMAT (code
);
4188 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4191 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4192 && XEXP (XEXP (x
, 0), 0) == reg
4193 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4194 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4197 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4199 /* If REG occurs inside a MEM used in a bit-field reference,
4200 that is unacceptable. */
4201 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4202 return (rtx
) (size_t) 1;
4206 return (rtx
) (size_t) 1;
4208 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4212 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4216 return (rtx
) (size_t) 1;
4218 else if (fmt
[i
] == 'E')
4221 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4223 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4227 return (rtx
) (size_t) 1;
4235 /* Write information about registers and basic blocks into FILE.
4236 This is part of making a debugging dump. */
4239 dump_regset (r
, outf
)
4246 fputs (" (nil)", outf
);
4250 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4252 fprintf (outf
, " %d", i
);
4253 if (i
< FIRST_PSEUDO_REGISTER
)
4254 fprintf (outf
, " [%s]",
4259 /* Print a human-readable representation of R on the standard error
4260 stream. This function is designed to be used from within the
4267 dump_regset (r
, stderr
);
4268 putc ('\n', stderr
);
4271 /* Recompute register set/reference counts immediately prior to register
4274 This avoids problems with set/reference counts changing to/from values
4275 which have special meanings to the register allocators.
4277 Additionally, the reference counts are the primary component used by the
4278 register allocators to prioritize pseudos for allocation to hard regs.
4279 More accurate reference counts generally lead to better register allocation.
4281 F is the first insn to be scanned.
4283 LOOP_STEP denotes how much loop_depth should be incremented per
4284 loop nesting level in order to increase the ref count more for
4285 references in a loop.
4287 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4288 possibly other information which is used by the register allocators. */
4291 recompute_reg_usage (f
, loop_step
)
4292 rtx f ATTRIBUTE_UNUSED
;
4293 int loop_step ATTRIBUTE_UNUSED
;
4295 allocate_reg_life_data ();
4296 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4299 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4300 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4301 of the number of registers that died. */
4304 count_or_remove_death_notes (blocks
, kill
)
4311 FOR_EACH_BB_REVERSE (bb
)
4315 if (blocks
&& ! TEST_BIT (blocks
, bb
->index
))
4318 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4322 rtx
*pprev
= ®_NOTES (insn
);
4327 switch (REG_NOTE_KIND (link
))
4330 if (GET_CODE (XEXP (link
, 0)) == REG
)
4332 rtx reg
= XEXP (link
, 0);
4335 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4338 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4346 rtx next
= XEXP (link
, 1);
4347 free_EXPR_LIST_node (link
);
4348 *pprev
= link
= next
;
4354 pprev
= &XEXP (link
, 1);
4361 if (insn
== bb
->end
)
4368 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4369 if blocks is NULL. */
4372 clear_log_links (blocks
)
4380 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4382 free_INSN_LIST_list (&LOG_LINKS (insn
));
4385 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4387 basic_block bb
= BASIC_BLOCK (i
);
4389 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4390 insn
= NEXT_INSN (insn
))
4392 free_INSN_LIST_list (&LOG_LINKS (insn
));
4396 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4397 correspond to the hard registers, if any, set in that map. This
4398 could be done far more efficiently by having all sorts of special-cases
4399 with moving single words, but probably isn't worth the trouble. */
4402 reg_set_to_hard_reg_set (to
, from
)
4408 EXECUTE_IF_SET_IN_BITMAP
4411 if (i
>= FIRST_PSEUDO_REGISTER
)
4413 SET_HARD_REG_BIT (*to
, i
);