1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #define EH_USES(REGNO) 0
174 #ifdef HAVE_conditional_execution
175 #ifndef REVERSE_CONDEXEC_PREDICATES_P
176 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
180 /* Nonzero if the second flow pass has completed. */
183 /* Maximum register number used in this function, plus one. */
187 /* Indexed by n, giving various register information */
189 varray_type reg_n_info
;
191 /* Size of a regset for the current function,
192 in (1) bytes and (2) elements. */
197 /* Regset of regs live when calls to `setjmp'-like functions happen. */
198 /* ??? Does this exist only for the setjmp-clobbered warning message? */
200 regset regs_live_at_setjmp
;
202 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
203 that have to go in the same hard reg.
204 The first two regs in the list are a pair, and the next two
205 are another pair, etc. */
208 /* Callback that determines if it's ok for a function to have no
209 noreturn attribute. */
210 int (*lang_missing_noreturn_ok_p
) PARAMS ((tree
));
212 /* Set of registers that may be eliminable. These are handled specially
213 in updating regs_ever_live. */
215 static HARD_REG_SET elim_reg_set
;
217 /* Holds information for tracking conditional register life information. */
218 struct reg_cond_life_info
220 /* A boolean expression of conditions under which a register is dead. */
222 /* Conditions under which a register is dead at the basic block end. */
225 /* A boolean expression of conditions under which a register has been
229 /* ??? Could store mask of bytes that are dead, so that we could finally
230 track lifetimes of multi-word registers accessed via subregs. */
233 /* For use in communicating between propagate_block and its subroutines.
234 Holds all information needed to compute life and def-use information. */
236 struct propagate_block_info
238 /* The basic block we're considering. */
241 /* Bit N is set if register N is conditionally or unconditionally live. */
244 /* Bit N is set if register N is set this insn. */
247 /* Element N is the next insn that uses (hard or pseudo) register N
248 within the current basic block; or zero, if there is no such insn. */
251 /* Contains a list of all the MEMs we are tracking for dead store
255 /* If non-null, record the set of registers set unconditionally in the
259 /* If non-null, record the set of registers set conditionally in the
261 regset cond_local_set
;
263 #ifdef HAVE_conditional_execution
264 /* Indexed by register number, holds a reg_cond_life_info for each
265 register that is not unconditionally live or dead. */
266 splay_tree reg_cond_dead
;
268 /* Bit N is set if register N is in an expression in reg_cond_dead. */
272 /* The length of mem_set_list. */
273 int mem_set_list_len
;
275 /* Non-zero if the value of CC0 is live. */
278 /* Flags controling the set of information propagate_block collects. */
282 /* Number of dead insns removed. */
285 /* Maximum length of pbi->mem_set_list before we start dropping
286 new elements on the floor. */
287 #define MAX_MEM_SET_LIST_LEN 100
289 /* Forward declarations */
290 static int verify_wide_reg_1
PARAMS ((rtx
*, void *));
291 static void verify_wide_reg
PARAMS ((int, basic_block
));
292 static void verify_local_live_at_start
PARAMS ((regset
, basic_block
));
293 static void notice_stack_pointer_modification_1
PARAMS ((rtx
, rtx
, void *));
294 static void notice_stack_pointer_modification
PARAMS ((rtx
));
295 static void mark_reg
PARAMS ((rtx
, void *));
296 static void mark_regs_live_at_end
PARAMS ((regset
));
297 static int set_phi_alternative_reg
PARAMS ((rtx
, int, int, void *));
298 static void calculate_global_regs_live
PARAMS ((sbitmap
, sbitmap
, int));
299 static void propagate_block_delete_insn
PARAMS ((rtx
));
300 static rtx propagate_block_delete_libcall
PARAMS ((rtx
, rtx
));
301 static int insn_dead_p
PARAMS ((struct propagate_block_info
*,
303 static int libcall_dead_p
PARAMS ((struct propagate_block_info
*,
305 static void mark_set_regs
PARAMS ((struct propagate_block_info
*,
307 static void mark_set_1
PARAMS ((struct propagate_block_info
*,
308 enum rtx_code
, rtx
, rtx
,
310 static int find_regno_partial
PARAMS ((rtx
*, void *));
312 #ifdef HAVE_conditional_execution
313 static int mark_regno_cond_dead
PARAMS ((struct propagate_block_info
*,
315 static void free_reg_cond_life_info
PARAMS ((splay_tree_value
));
316 static int flush_reg_cond_reg_1
PARAMS ((splay_tree_node
, void *));
317 static void flush_reg_cond_reg
PARAMS ((struct propagate_block_info
*,
319 static rtx elim_reg_cond
PARAMS ((rtx
, unsigned int));
320 static rtx ior_reg_cond
PARAMS ((rtx
, rtx
, int));
321 static rtx not_reg_cond
PARAMS ((rtx
));
322 static rtx and_reg_cond
PARAMS ((rtx
, rtx
, int));
325 static void attempt_auto_inc
PARAMS ((struct propagate_block_info
*,
326 rtx
, rtx
, rtx
, rtx
, rtx
));
327 static void find_auto_inc
PARAMS ((struct propagate_block_info
*,
329 static int try_pre_increment_1
PARAMS ((struct propagate_block_info
*,
331 static int try_pre_increment
PARAMS ((rtx
, rtx
, HOST_WIDE_INT
));
333 static void mark_used_reg
PARAMS ((struct propagate_block_info
*,
335 static void mark_used_regs
PARAMS ((struct propagate_block_info
*,
337 void dump_flow_info
PARAMS ((FILE *));
338 void debug_flow_info
PARAMS ((void));
339 static void add_to_mem_set_list
PARAMS ((struct propagate_block_info
*,
341 static int invalidate_mems_from_autoinc
PARAMS ((rtx
*, void *));
342 static void invalidate_mems_from_set
PARAMS ((struct propagate_block_info
*,
344 static void clear_log_links
PARAMS ((sbitmap
));
348 check_function_return_warnings ()
350 if (warn_missing_noreturn
351 && !TREE_THIS_VOLATILE (cfun
->decl
)
352 && EXIT_BLOCK_PTR
->pred
== NULL
353 && (lang_missing_noreturn_ok_p
354 && !lang_missing_noreturn_ok_p (cfun
->decl
)))
355 warning ("function might be possible candidate for attribute `noreturn'");
357 /* If we have a path to EXIT, then we do return. */
358 if (TREE_THIS_VOLATILE (cfun
->decl
)
359 && EXIT_BLOCK_PTR
->pred
!= NULL
)
360 warning ("`noreturn' function does return");
362 /* If the clobber_return_insn appears in some basic block, then we
363 do reach the end without returning a value. */
364 else if (warn_return_type
365 && cfun
->x_clobber_return_insn
!= NULL
366 && EXIT_BLOCK_PTR
->pred
!= NULL
)
368 int max_uid
= get_max_uid ();
370 /* If clobber_return_insn was excised by jump1, then renumber_insns
371 can make max_uid smaller than the number still recorded in our rtx.
372 That's fine, since this is a quick way of verifying that the insn
373 is no longer in the chain. */
374 if (INSN_UID (cfun
->x_clobber_return_insn
) < max_uid
)
376 /* Recompute insn->block mapping, since the initial mapping is
377 set before we delete unreachable blocks. */
378 if (BLOCK_FOR_INSN (cfun
->x_clobber_return_insn
) != NULL
)
379 warning ("control reaches end of non-void function");
384 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
385 note associated with the BLOCK. */
388 first_insn_after_basic_block_note (block
)
393 /* Get the first instruction in the block. */
396 if (insn
== NULL_RTX
)
398 if (GET_CODE (insn
) == CODE_LABEL
)
399 insn
= NEXT_INSN (insn
);
400 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
403 return NEXT_INSN (insn
);
406 /* Perform data flow analysis.
407 F is the first insn of the function; FLAGS is a set of PROP_* flags
408 to be used in accumulating flow info. */
411 life_analysis (f
, file
, flags
)
416 #ifdef ELIMINABLE_REGS
418 static const struct {const int from
, to
; } eliminables
[] = ELIMINABLE_REGS
;
421 /* Record which registers will be eliminated. We use this in
424 CLEAR_HARD_REG_SET (elim_reg_set
);
426 #ifdef ELIMINABLE_REGS
427 for (i
= 0; i
< (int) ARRAY_SIZE (eliminables
); i
++)
428 SET_HARD_REG_BIT (elim_reg_set
, eliminables
[i
].from
);
430 SET_HARD_REG_BIT (elim_reg_set
, FRAME_POINTER_REGNUM
);
434 flags
&= ~(PROP_LOG_LINKS
| PROP_AUTOINC
| PROP_ALLOW_CFG_CHANGES
);
436 /* The post-reload life analysis have (on a global basis) the same
437 registers live as was computed by reload itself. elimination
438 Otherwise offsets and such may be incorrect.
440 Reload will make some registers as live even though they do not
443 We don't want to create new auto-incs after reload, since they
444 are unlikely to be useful and can cause problems with shared
446 if (reload_completed
)
447 flags
&= ~(PROP_REG_INFO
| PROP_AUTOINC
);
449 /* We want alias analysis information for local dead store elimination. */
450 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
451 init_alias_analysis ();
453 /* Always remove no-op moves. Do this before other processing so
454 that we don't have to keep re-scanning them. */
455 delete_noop_moves (f
);
457 /* Some targets can emit simpler epilogues if they know that sp was
458 not ever modified during the function. After reload, of course,
459 we've already emitted the epilogue so there's no sense searching. */
460 if (! reload_completed
)
461 notice_stack_pointer_modification (f
);
463 /* Allocate and zero out data structures that will record the
464 data from lifetime analysis. */
465 allocate_reg_life_data ();
466 allocate_bb_life_data ();
468 /* Find the set of registers live on function exit. */
469 mark_regs_live_at_end (EXIT_BLOCK_PTR
->global_live_at_start
);
471 /* "Update" life info from zero. It'd be nice to begin the
472 relaxation with just the exit and noreturn blocks, but that set
473 is not immediately handy. */
475 if (flags
& PROP_REG_INFO
)
476 memset (regs_ever_live
, 0, sizeof (regs_ever_live
));
477 update_life_info (NULL
, UPDATE_LIFE_GLOBAL
, flags
);
480 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
481 end_alias_analysis ();
484 dump_flow_info (file
);
486 free_basic_block_vars (1);
488 #ifdef ENABLE_CHECKING
492 /* Search for any REG_LABEL notes which reference deleted labels. */
493 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
495 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
496 if (inote
&& GET_CODE (XEXP (inote
, 0)) != CODE_LABEL
)
502 /* Removing dead insns should've made jumptables really dead. */
503 delete_dead_jumptables ();
506 /* A subroutine of verify_wide_reg, called through for_each_rtx.
507 Search for REGNO. If found, return 2 if it is not wider than
511 verify_wide_reg_1 (px
, pregno
)
516 unsigned int regno
= *(int *) pregno
;
518 if (GET_CODE (x
) == REG
&& REGNO (x
) == regno
)
520 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
)
527 /* A subroutine of verify_local_live_at_start. Search through insns
528 of BB looking for register REGNO. */
531 verify_wide_reg (regno
, bb
)
535 rtx head
= bb
->head
, end
= bb
->end
;
541 int r
= for_each_rtx (&PATTERN (head
), verify_wide_reg_1
, ®no
);
549 head
= NEXT_INSN (head
);
554 fprintf (rtl_dump_file
, "Register %d died unexpectedly.\n", regno
);
555 dump_bb (bb
, rtl_dump_file
);
560 /* A subroutine of update_life_info. Verify that there are no untoward
561 changes in live_at_start during a local update. */
564 verify_local_live_at_start (new_live_at_start
, bb
)
565 regset new_live_at_start
;
568 if (reload_completed
)
570 /* After reload, there are no pseudos, nor subregs of multi-word
571 registers. The regsets should exactly match. */
572 if (! REG_SET_EQUAL_P (new_live_at_start
, bb
->global_live_at_start
))
576 fprintf (rtl_dump_file
,
577 "live_at_start mismatch in bb %d, aborting\nNew:\n",
579 debug_bitmap_file (rtl_dump_file
, new_live_at_start
);
580 fputs ("Old:\n", rtl_dump_file
);
581 dump_bb (bb
, rtl_dump_file
);
590 /* Find the set of changed registers. */
591 XOR_REG_SET (new_live_at_start
, bb
->global_live_at_start
);
593 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start
, 0, i
,
595 /* No registers should die. */
596 if (REGNO_REG_SET_P (bb
->global_live_at_start
, i
))
600 fprintf (rtl_dump_file
,
601 "Register %d died unexpectedly.\n", i
);
602 dump_bb (bb
, rtl_dump_file
);
607 /* Verify that the now-live register is wider than word_mode. */
608 verify_wide_reg (i
, bb
);
613 /* Updates life information starting with the basic blocks set in BLOCKS.
614 If BLOCKS is null, consider it to be the universal set.
616 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
617 we are only expecting local modifications to basic blocks. If we find
618 extra registers live at the beginning of a block, then we either killed
619 useful data, or we have a broken split that wants data not provided.
620 If we find registers removed from live_at_start, that means we have
621 a broken peephole that is killing a register it shouldn't.
623 ??? This is not true in one situation -- when a pre-reload splitter
624 generates subregs of a multi-word pseudo, current life analysis will
625 lose the kill. So we _can_ have a pseudo go live. How irritating.
627 Including PROP_REG_INFO does not properly refresh regs_ever_live
628 unless the caller resets it to zero. */
631 update_life_info (blocks
, extent
, prop_flags
)
633 enum update_life_extent extent
;
637 regset_head tmp_head
;
639 int stabilized_prop_flags
= prop_flags
;
641 tmp
= INITIALIZE_REG_SET (tmp_head
);
644 timevar_push ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
645 ? TV_LIFE_UPDATE
: TV_LIFE
);
647 /* Changes to the CFG are only allowed when
648 doing a global update for the entire CFG. */
649 if ((prop_flags
& PROP_ALLOW_CFG_CHANGES
)
650 && (extent
== UPDATE_LIFE_LOCAL
|| blocks
))
653 /* For a global update, we go through the relaxation process again. */
654 if (extent
!= UPDATE_LIFE_LOCAL
)
660 calculate_global_regs_live (blocks
, blocks
,
661 prop_flags
& (PROP_SCAN_DEAD_CODE
662 | PROP_ALLOW_CFG_CHANGES
));
664 if ((prop_flags
& (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
665 != (PROP_KILL_DEAD_CODE
| PROP_ALLOW_CFG_CHANGES
))
668 /* Removing dead code may allow the CFG to be simplified which
669 in turn may allow for further dead code detection / removal. */
670 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
672 basic_block bb
= BASIC_BLOCK (i
);
674 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
675 changed
|= propagate_block (bb
, tmp
, NULL
, NULL
,
676 prop_flags
& (PROP_SCAN_DEAD_CODE
677 | PROP_KILL_DEAD_CODE
));
680 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
681 subsequent propagate_block calls, since removing or acting as
682 removing dead code can affect global register liveness, which
683 is supposed to be finalized for this call after this loop. */
684 stabilized_prop_flags
685 &= ~(PROP_SCAN_DEAD_CODE
| PROP_KILL_DEAD_CODE
);
690 /* We repeat regardless of what cleanup_cfg says. If there were
691 instructions deleted above, that might have been only a
692 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
693 Further improvement may be possible. */
694 cleanup_cfg (CLEANUP_EXPENSIVE
);
697 /* If asked, remove notes from the blocks we'll update. */
698 if (extent
== UPDATE_LIFE_GLOBAL_RM_NOTES
)
699 count_or_remove_death_notes (blocks
, 1);
702 /* Clear log links in case we are asked to (re)compute them. */
703 if (prop_flags
& PROP_LOG_LINKS
)
704 clear_log_links (blocks
);
708 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
710 basic_block bb
= BASIC_BLOCK (i
);
712 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
713 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
715 if (extent
== UPDATE_LIFE_LOCAL
)
716 verify_local_live_at_start (tmp
, bb
);
721 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
723 basic_block bb
= BASIC_BLOCK (i
);
725 COPY_REG_SET (tmp
, bb
->global_live_at_end
);
727 propagate_block (bb
, tmp
, NULL
, NULL
, stabilized_prop_flags
);
729 if (extent
== UPDATE_LIFE_LOCAL
)
730 verify_local_live_at_start (tmp
, bb
);
736 if (prop_flags
& PROP_REG_INFO
)
738 /* The only pseudos that are live at the beginning of the function
739 are those that were not set anywhere in the function. local-alloc
740 doesn't know how to handle these correctly, so mark them as not
741 local to any one basic block. */
742 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR
->global_live_at_end
,
743 FIRST_PSEUDO_REGISTER
, i
,
744 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
746 /* We have a problem with any pseudoreg that lives across the setjmp.
747 ANSI says that if a user variable does not change in value between
748 the setjmp and the longjmp, then the longjmp preserves it. This
749 includes longjmp from a place where the pseudo appears dead.
750 (In principle, the value still exists if it is in scope.)
751 If the pseudo goes in a hard reg, some other value may occupy
752 that hard reg where this pseudo is dead, thus clobbering the pseudo.
753 Conclusion: such a pseudo must not go in a hard reg. */
754 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp
,
755 FIRST_PSEUDO_REGISTER
, i
,
757 if (regno_reg_rtx
[i
] != 0)
759 REG_LIVE_LENGTH (i
) = -1;
760 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
764 timevar_pop ((extent
== UPDATE_LIFE_LOCAL
|| blocks
)
765 ? TV_LIFE_UPDATE
: TV_LIFE
);
766 if (ndead
&& rtl_dump_file
)
767 fprintf (rtl_dump_file
, "deleted %i dead insns\n", ndead
);
771 /* Update life information in all blocks where BB_DIRTY is set. */
774 update_life_info_in_dirty_blocks (extent
, prop_flags
)
775 enum update_life_extent extent
;
778 sbitmap update_life_blocks
= sbitmap_alloc (n_basic_blocks
);
783 sbitmap_zero (update_life_blocks
);
784 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
785 if (BASIC_BLOCK (block_num
)->flags
& BB_DIRTY
)
787 SET_BIT (update_life_blocks
, block_num
);
792 retval
= update_life_info (update_life_blocks
, extent
, prop_flags
);
794 sbitmap_free (update_life_blocks
);
798 /* Free the variables allocated by find_basic_blocks.
800 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
803 free_basic_block_vars (keep_head_end_p
)
806 if (! keep_head_end_p
)
808 if (basic_block_info
)
811 VARRAY_FREE (basic_block_info
);
815 ENTRY_BLOCK_PTR
->aux
= NULL
;
816 ENTRY_BLOCK_PTR
->global_live_at_end
= NULL
;
817 EXIT_BLOCK_PTR
->aux
= NULL
;
818 EXIT_BLOCK_PTR
->global_live_at_start
= NULL
;
822 /* Delete any insns that copy a register to itself. */
825 delete_noop_moves (f
)
826 rtx f ATTRIBUTE_UNUSED
;
833 for (i
= 0; i
< n_basic_blocks
; i
++)
835 bb
= BASIC_BLOCK (i
);
836 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
); insn
= next
)
838 next
= NEXT_INSN (insn
);
839 if (INSN_P (insn
) && noop_move_p (insn
))
843 /* If we're about to remove the first insn of a libcall
844 then move the libcall note to the next real insn and
845 update the retval note. */
846 if ((note
= find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
847 && XEXP (note
, 0) != insn
)
849 rtx new_libcall_insn
= next_real_insn (insn
);
850 rtx retval_note
= find_reg_note (XEXP (note
, 0),
851 REG_RETVAL
, NULL_RTX
);
852 REG_NOTES (new_libcall_insn
)
853 = gen_rtx_INSN_LIST (REG_LIBCALL
, XEXP (note
, 0),
854 REG_NOTES (new_libcall_insn
));
855 XEXP (retval_note
, 0) = new_libcall_insn
;
858 delete_insn_and_edges (insn
);
863 if (nnoops
&& rtl_dump_file
)
864 fprintf (rtl_dump_file
, "deleted %i noop moves", nnoops
);
868 /* Delete any jump tables never referenced. We can't delete them at the
869 time of removing tablejump insn as they are referenced by the preceding
870 insns computing the destination, so we delay deleting and garbagecollect
871 them once life information is computed. */
873 delete_dead_jumptables ()
876 for (insn
= get_insns (); insn
; insn
= next
)
878 next
= NEXT_INSN (insn
);
879 if (GET_CODE (insn
) == CODE_LABEL
880 && LABEL_NUSES (insn
) == LABEL_PRESERVE_P (insn
)
881 && GET_CODE (next
) == JUMP_INSN
882 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
883 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
886 fprintf (rtl_dump_file
, "Dead jumptable %i removed\n", INSN_UID (insn
));
887 delete_insn (NEXT_INSN (insn
));
889 next
= NEXT_INSN (next
);
894 /* Determine if the stack pointer is constant over the life of the function.
895 Only useful before prologues have been emitted. */
898 notice_stack_pointer_modification_1 (x
, pat
, data
)
900 rtx pat ATTRIBUTE_UNUSED
;
901 void *data ATTRIBUTE_UNUSED
;
903 if (x
== stack_pointer_rtx
904 /* The stack pointer is only modified indirectly as the result
905 of a push until later in flow. See the comments in rtl.texi
906 regarding Embedded Side-Effects on Addresses. */
907 || (GET_CODE (x
) == MEM
908 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'a'
909 && XEXP (XEXP (x
, 0), 0) == stack_pointer_rtx
))
910 current_function_sp_is_unchanging
= 0;
914 notice_stack_pointer_modification (f
)
919 /* Assume that the stack pointer is unchanging if alloca hasn't
921 current_function_sp_is_unchanging
= !current_function_calls_alloca
;
922 if (! current_function_sp_is_unchanging
)
925 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
929 /* Check if insn modifies the stack pointer. */
930 note_stores (PATTERN (insn
), notice_stack_pointer_modification_1
,
932 if (! current_function_sp_is_unchanging
)
938 /* Mark a register in SET. Hard registers in large modes get all
939 of their component registers set as well. */
946 regset set
= (regset
) xset
;
947 int regno
= REGNO (reg
);
949 if (GET_MODE (reg
) == BLKmode
)
952 SET_REGNO_REG_SET (set
, regno
);
953 if (regno
< FIRST_PSEUDO_REGISTER
)
955 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (reg
));
957 SET_REGNO_REG_SET (set
, regno
+ n
);
961 /* Mark those regs which are needed at the end of the function as live
962 at the end of the last basic block. */
965 mark_regs_live_at_end (set
)
970 /* If exiting needs the right stack value, consider the stack pointer
971 live at the end of the function. */
972 if ((HAVE_epilogue
&& reload_completed
)
973 || ! EXIT_IGNORE_STACK
974 || (! FRAME_POINTER_REQUIRED
975 && ! current_function_calls_alloca
976 && flag_omit_frame_pointer
)
977 || current_function_sp_is_unchanging
)
979 SET_REGNO_REG_SET (set
, STACK_POINTER_REGNUM
);
982 /* Mark the frame pointer if needed at the end of the function. If
983 we end up eliminating it, it will be removed from the live list
984 of each basic block by reload. */
986 if (! reload_completed
|| frame_pointer_needed
)
988 SET_REGNO_REG_SET (set
, FRAME_POINTER_REGNUM
);
989 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
990 /* If they are different, also mark the hard frame pointer as live. */
991 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM
))
992 SET_REGNO_REG_SET (set
, HARD_FRAME_POINTER_REGNUM
);
996 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
997 /* Many architectures have a GP register even without flag_pic.
998 Assume the pic register is not in use, or will be handled by
999 other means, if it is not fixed. */
1000 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1001 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1002 SET_REGNO_REG_SET (set
, PIC_OFFSET_TABLE_REGNUM
);
1005 /* Mark all global registers, and all registers used by the epilogue
1006 as being live at the end of the function since they may be
1007 referenced by our caller. */
1008 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1009 if (global_regs
[i
] || EPILOGUE_USES (i
))
1010 SET_REGNO_REG_SET (set
, i
);
1012 if (HAVE_epilogue
&& reload_completed
)
1014 /* Mark all call-saved registers that we actually used. */
1015 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1016 if (regs_ever_live
[i
] && ! LOCAL_REGNO (i
)
1017 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1018 SET_REGNO_REG_SET (set
, i
);
1021 #ifdef EH_RETURN_DATA_REGNO
1022 /* Mark the registers that will contain data for the handler. */
1023 if (reload_completed
&& current_function_calls_eh_return
)
1026 unsigned regno
= EH_RETURN_DATA_REGNO(i
);
1027 if (regno
== INVALID_REGNUM
)
1029 SET_REGNO_REG_SET (set
, regno
);
1032 #ifdef EH_RETURN_STACKADJ_RTX
1033 if ((! HAVE_epilogue
|| ! reload_completed
)
1034 && current_function_calls_eh_return
)
1036 rtx tmp
= EH_RETURN_STACKADJ_RTX
;
1037 if (tmp
&& REG_P (tmp
))
1038 mark_reg (tmp
, set
);
1041 #ifdef EH_RETURN_HANDLER_RTX
1042 if ((! HAVE_epilogue
|| ! reload_completed
)
1043 && current_function_calls_eh_return
)
1045 rtx tmp
= EH_RETURN_HANDLER_RTX
;
1046 if (tmp
&& REG_P (tmp
))
1047 mark_reg (tmp
, set
);
1051 /* Mark function return value. */
1052 diddle_return_value (mark_reg
, set
);
1055 /* Callback function for for_each_successor_phi. DATA is a regset.
1056 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1057 INSN, in the regset. */
1060 set_phi_alternative_reg (insn
, dest_regno
, src_regno
, data
)
1061 rtx insn ATTRIBUTE_UNUSED
;
1062 int dest_regno ATTRIBUTE_UNUSED
;
1066 regset live
= (regset
) data
;
1067 SET_REGNO_REG_SET (live
, src_regno
);
1071 /* Propagate global life info around the graph of basic blocks. Begin
1072 considering blocks with their corresponding bit set in BLOCKS_IN.
1073 If BLOCKS_IN is null, consider it the universal set.
1075 BLOCKS_OUT is set for every block that was changed. */
1078 calculate_global_regs_live (blocks_in
, blocks_out
, flags
)
1079 sbitmap blocks_in
, blocks_out
;
1082 basic_block
*queue
, *qhead
, *qtail
, *qend
;
1083 regset tmp
, new_live_at_end
, call_used
;
1084 regset_head tmp_head
, call_used_head
;
1085 regset_head new_live_at_end_head
;
1088 /* Some passes used to forget clear aux field of basic block causing
1089 sick behaviour here. */
1090 #ifdef ENABLE_CHECKING
1091 if (ENTRY_BLOCK_PTR
->aux
|| EXIT_BLOCK_PTR
->aux
)
1093 for (i
= 0; i
< n_basic_blocks
; i
++)
1094 if (BASIC_BLOCK (i
)->aux
)
1098 tmp
= INITIALIZE_REG_SET (tmp_head
);
1099 new_live_at_end
= INITIALIZE_REG_SET (new_live_at_end_head
);
1100 call_used
= INITIALIZE_REG_SET (call_used_head
);
1102 /* Inconveniently, this is only readily available in hard reg set form. */
1103 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; ++i
)
1104 if (call_used_regs
[i
])
1105 SET_REGNO_REG_SET (call_used
, i
);
1107 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1108 because the `head == tail' style test for an empty queue doesn't
1109 work with a full queue. */
1110 queue
= (basic_block
*) xmalloc ((n_basic_blocks
+ 2) * sizeof (*queue
));
1112 qhead
= qend
= queue
+ n_basic_blocks
+ 2;
1114 /* Queue the blocks set in the initial mask. Do this in reverse block
1115 number order so that we are more likely for the first round to do
1116 useful work. We use AUX non-null to flag that the block is queued. */
1119 /* Clear out the garbage that might be hanging out in bb->aux. */
1120 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1121 BASIC_BLOCK (i
)->aux
= NULL
;
1123 EXECUTE_IF_SET_IN_SBITMAP (blocks_in
, 0, i
,
1125 basic_block bb
= BASIC_BLOCK (i
);
1132 for (i
= 0; i
< n_basic_blocks
; ++i
)
1134 basic_block bb
= BASIC_BLOCK (i
);
1140 /* We clean aux when we remove the initially-enqueued bbs, but we
1141 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1143 ENTRY_BLOCK_PTR
->aux
= EXIT_BLOCK_PTR
->aux
= NULL
;
1146 sbitmap_zero (blocks_out
);
1148 /* We work through the queue until there are no more blocks. What
1149 is live at the end of this block is precisely the union of what
1150 is live at the beginning of all its successors. So, we set its
1151 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1152 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1153 this block by walking through the instructions in this block in
1154 reverse order and updating as we go. If that changed
1155 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1156 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1158 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1159 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1160 must either be live at the end of the block, or used within the
1161 block. In the latter case, it will certainly never disappear
1162 from GLOBAL_LIVE_AT_START. In the former case, the register
1163 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1164 for one of the successor blocks. By induction, that cannot
1166 while (qhead
!= qtail
)
1168 int rescan
, changed
;
1177 /* Begin by propagating live_at_start from the successor blocks. */
1178 CLEAR_REG_SET (new_live_at_end
);
1181 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1183 basic_block sb
= e
->dest
;
1185 /* Call-clobbered registers die across exception and
1187 /* ??? Abnormal call edges ignored for the moment, as this gets
1188 confused by sibling call edges, which crashes reg-stack. */
1189 if (e
->flags
& EDGE_EH
)
1191 bitmap_operation (tmp
, sb
->global_live_at_start
,
1192 call_used
, BITMAP_AND_COMPL
);
1193 IOR_REG_SET (new_live_at_end
, tmp
);
1196 IOR_REG_SET (new_live_at_end
, sb
->global_live_at_start
);
1198 /* If a target saves one register in another (instead of on
1199 the stack) the save register will need to be live for EH. */
1200 if (e
->flags
& EDGE_EH
)
1201 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1203 SET_REGNO_REG_SET (new_live_at_end
, i
);
1207 /* This might be a noreturn function that throws. And
1208 even if it isn't, getting the unwind info right helps
1210 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1212 SET_REGNO_REG_SET (new_live_at_end
, i
);
1215 /* The all-important stack pointer must always be live. */
1216 SET_REGNO_REG_SET (new_live_at_end
, STACK_POINTER_REGNUM
);
1218 /* Before reload, there are a few registers that must be forced
1219 live everywhere -- which might not already be the case for
1220 blocks within infinite loops. */
1221 if (! reload_completed
)
1223 /* Any reference to any pseudo before reload is a potential
1224 reference of the frame pointer. */
1225 SET_REGNO_REG_SET (new_live_at_end
, FRAME_POINTER_REGNUM
);
1227 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1228 /* Pseudos with argument area equivalences may require
1229 reloading via the argument pointer. */
1230 if (fixed_regs
[ARG_POINTER_REGNUM
])
1231 SET_REGNO_REG_SET (new_live_at_end
, ARG_POINTER_REGNUM
);
1234 /* Any constant, or pseudo with constant equivalences, may
1235 require reloading from memory using the pic register. */
1236 if (PIC_OFFSET_TABLE_REGNUM
!= INVALID_REGNUM
1237 && fixed_regs
[PIC_OFFSET_TABLE_REGNUM
])
1238 SET_REGNO_REG_SET (new_live_at_end
, PIC_OFFSET_TABLE_REGNUM
);
1241 /* Regs used in phi nodes are not included in
1242 global_live_at_start, since they are live only along a
1243 particular edge. Set those regs that are live because of a
1244 phi node alternative corresponding to this particular block. */
1246 for_each_successor_phi (bb
, &set_phi_alternative_reg
,
1249 if (bb
== ENTRY_BLOCK_PTR
)
1251 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1255 /* On our first pass through this block, we'll go ahead and continue.
1256 Recognize first pass by local_set NULL. On subsequent passes, we
1257 get to skip out early if live_at_end wouldn't have changed. */
1259 if (bb
->local_set
== NULL
)
1261 bb
->local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1262 bb
->cond_local_set
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1267 /* If any bits were removed from live_at_end, we'll have to
1268 rescan the block. This wouldn't be necessary if we had
1269 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1270 local_live is really dependent on live_at_end. */
1271 CLEAR_REG_SET (tmp
);
1272 rescan
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1273 new_live_at_end
, BITMAP_AND_COMPL
);
1277 /* If any of the registers in the new live_at_end set are
1278 conditionally set in this basic block, we must rescan.
1279 This is because conditional lifetimes at the end of the
1280 block do not just take the live_at_end set into account,
1281 but also the liveness at the start of each successor
1282 block. We can miss changes in those sets if we only
1283 compare the new live_at_end against the previous one. */
1284 CLEAR_REG_SET (tmp
);
1285 rescan
= bitmap_operation (tmp
, new_live_at_end
,
1286 bb
->cond_local_set
, BITMAP_AND
);
1291 /* Find the set of changed bits. Take this opportunity
1292 to notice that this set is empty and early out. */
1293 CLEAR_REG_SET (tmp
);
1294 changed
= bitmap_operation (tmp
, bb
->global_live_at_end
,
1295 new_live_at_end
, BITMAP_XOR
);
1299 /* If any of the changed bits overlap with local_set,
1300 we'll have to rescan the block. Detect overlap by
1301 the AND with ~local_set turning off bits. */
1302 rescan
= bitmap_operation (tmp
, tmp
, bb
->local_set
,
1307 /* Let our caller know that BB changed enough to require its
1308 death notes updated. */
1310 SET_BIT (blocks_out
, bb
->index
);
1314 /* Add to live_at_start the set of all registers in
1315 new_live_at_end that aren't in the old live_at_end. */
1317 bitmap_operation (tmp
, new_live_at_end
, bb
->global_live_at_end
,
1319 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1321 changed
= bitmap_operation (bb
->global_live_at_start
,
1322 bb
->global_live_at_start
,
1329 COPY_REG_SET (bb
->global_live_at_end
, new_live_at_end
);
1331 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1332 into live_at_start. */
1333 propagate_block (bb
, new_live_at_end
, bb
->local_set
,
1334 bb
->cond_local_set
, flags
);
1336 /* If live_at start didn't change, no need to go farther. */
1337 if (REG_SET_EQUAL_P (bb
->global_live_at_start
, new_live_at_end
))
1340 COPY_REG_SET (bb
->global_live_at_start
, new_live_at_end
);
1343 /* Queue all predecessors of BB so that we may re-examine
1344 their live_at_end. */
1345 for (e
= bb
->pred
; e
; e
= e
->pred_next
)
1347 basic_block pb
= e
->src
;
1348 if (pb
->aux
== NULL
)
1359 FREE_REG_SET (new_live_at_end
);
1360 FREE_REG_SET (call_used
);
1364 EXECUTE_IF_SET_IN_SBITMAP (blocks_out
, 0, i
,
1366 basic_block bb
= BASIC_BLOCK (i
);
1367 FREE_REG_SET (bb
->local_set
);
1368 FREE_REG_SET (bb
->cond_local_set
);
1373 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
1375 basic_block bb
= BASIC_BLOCK (i
);
1376 FREE_REG_SET (bb
->local_set
);
1377 FREE_REG_SET (bb
->cond_local_set
);
1385 /* This structure is used to pass parameters to an from the
1386 the function find_regno_partial(). It is used to pass in the
1387 register number we are looking, as well as to return any rtx
1391 unsigned regno_to_find
;
1393 } find_regno_partial_param
;
1396 /* Find the rtx for the reg numbers specified in 'data' if it is
1397 part of an expression which only uses part of the register. Return
1398 it in the structure passed in. */
1400 find_regno_partial (ptr
, data
)
1404 find_regno_partial_param
*param
= (find_regno_partial_param
*)data
;
1405 unsigned reg
= param
->regno_to_find
;
1406 param
->retval
= NULL_RTX
;
1408 if (*ptr
== NULL_RTX
)
1411 switch (GET_CODE (*ptr
))
1415 case STRICT_LOW_PART
:
1416 if (GET_CODE (XEXP (*ptr
, 0)) == REG
&& REGNO (XEXP (*ptr
, 0)) == reg
)
1418 param
->retval
= XEXP (*ptr
, 0);
1424 if (GET_CODE (SUBREG_REG (*ptr
)) == REG
1425 && REGNO (SUBREG_REG (*ptr
)) == reg
)
1427 param
->retval
= SUBREG_REG (*ptr
);
1439 /* Process all immediate successors of the entry block looking for pseudo
1440 registers which are live on entry. Find all of those whose first
1441 instance is a partial register reference of some kind, and initialize
1442 them to 0 after the entry block. This will prevent bit sets within
1443 registers whose value is unknown, and may contain some kind of sticky
1444 bits we don't want. */
1447 initialize_uninitialized_subregs ()
1451 int reg
, did_something
= 0;
1452 find_regno_partial_param param
;
1454 for (e
= ENTRY_BLOCK_PTR
->succ
; e
; e
= e
->succ_next
)
1456 basic_block bb
= e
->dest
;
1457 regset map
= bb
->global_live_at_start
;
1458 EXECUTE_IF_SET_IN_REG_SET (map
,
1459 FIRST_PSEUDO_REGISTER
, reg
,
1461 int uid
= REGNO_FIRST_UID (reg
);
1464 /* Find an insn which mentions the register we are looking for.
1465 Its preferable to have an instance of the register's rtl since
1466 there may be various flags set which we need to duplicate.
1467 If we can't find it, its probably an automatic whose initial
1468 value doesn't matter, or hopefully something we don't care about. */
1469 for (i
= get_insns (); i
&& INSN_UID (i
) != uid
; i
= NEXT_INSN (i
))
1473 /* Found the insn, now get the REG rtx, if we can. */
1474 param
.regno_to_find
= reg
;
1475 for_each_rtx (&i
, find_regno_partial
, ¶m
);
1476 if (param
.retval
!= NULL_RTX
)
1478 insn
= gen_move_insn (param
.retval
,
1479 CONST0_RTX (GET_MODE (param
.retval
)));
1480 insert_insn_on_edge (insn
, e
);
1488 commit_edge_insertions ();
1489 return did_something
;
1493 /* Subroutines of life analysis. */
1495 /* Allocate the permanent data structures that represent the results
1496 of life analysis. Not static since used also for stupid life analysis. */
1499 allocate_bb_life_data ()
1503 for (i
= 0; i
< n_basic_blocks
; i
++)
1505 basic_block bb
= BASIC_BLOCK (i
);
1507 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1508 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1511 ENTRY_BLOCK_PTR
->global_live_at_end
1512 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1513 EXIT_BLOCK_PTR
->global_live_at_start
1514 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1516 regs_live_at_setjmp
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1520 allocate_reg_life_data ()
1524 max_regno
= max_reg_num ();
1526 /* Recalculate the register space, in case it has grown. Old style
1527 vector oriented regsets would set regset_{size,bytes} here also. */
1528 allocate_reg_info (max_regno
, FALSE
, FALSE
);
1530 /* Reset all the data we'll collect in propagate_block and its
1532 for (i
= 0; i
< max_regno
; i
++)
1536 REG_N_DEATHS (i
) = 0;
1537 REG_N_CALLS_CROSSED (i
) = 0;
1538 REG_LIVE_LENGTH (i
) = 0;
1539 REG_BASIC_BLOCK (i
) = REG_BLOCK_UNKNOWN
;
1543 /* Delete dead instructions for propagate_block. */
1546 propagate_block_delete_insn (insn
)
1549 rtx inote
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
);
1551 /* If the insn referred to a label, and that label was attached to
1552 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1553 pretty much mandatory to delete it, because the ADDR_VEC may be
1554 referencing labels that no longer exist.
1556 INSN may reference a deleted label, particularly when a jump
1557 table has been optimized into a direct jump. There's no
1558 real good way to fix up the reference to the deleted label
1559 when the label is deleted, so we just allow it here.
1561 After dead code elimination is complete, we do search for
1562 any REG_LABEL notes which reference deleted labels as a
1565 if (inote
&& GET_CODE (inote
) == CODE_LABEL
)
1567 rtx label
= XEXP (inote
, 0);
1570 /* The label may be forced if it has been put in the constant
1571 pool. If that is the only use we must discard the table
1572 jump following it, but not the label itself. */
1573 if (LABEL_NUSES (label
) == 1 + LABEL_PRESERVE_P (label
)
1574 && (next
= next_nonnote_insn (label
)) != NULL
1575 && GET_CODE (next
) == JUMP_INSN
1576 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
1577 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
))
1579 rtx pat
= PATTERN (next
);
1580 int diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1581 int len
= XVECLEN (pat
, diff_vec_p
);
1584 for (i
= 0; i
< len
; i
++)
1585 LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0))--;
1587 delete_insn_and_edges (next
);
1592 delete_insn_and_edges (insn
);
1596 /* Delete dead libcalls for propagate_block. Return the insn
1597 before the libcall. */
1600 propagate_block_delete_libcall ( insn
, note
)
1603 rtx first
= XEXP (note
, 0);
1604 rtx before
= PREV_INSN (first
);
1606 delete_insn_chain_and_edges (first
, insn
);
1611 /* Update the life-status of regs for one insn. Return the previous insn. */
1614 propagate_one_insn (pbi
, insn
)
1615 struct propagate_block_info
*pbi
;
1618 rtx prev
= PREV_INSN (insn
);
1619 int flags
= pbi
->flags
;
1620 int insn_is_dead
= 0;
1621 int libcall_is_dead
= 0;
1625 if (! INSN_P (insn
))
1628 note
= find_reg_note (insn
, REG_RETVAL
, NULL_RTX
);
1629 if (flags
& PROP_SCAN_DEAD_CODE
)
1631 insn_is_dead
= insn_dead_p (pbi
, PATTERN (insn
), 0, REG_NOTES (insn
));
1632 libcall_is_dead
= (insn_is_dead
&& note
!= 0
1633 && libcall_dead_p (pbi
, note
, insn
));
1636 /* If an instruction consists of just dead store(s) on final pass,
1638 if ((flags
& PROP_KILL_DEAD_CODE
) && insn_is_dead
)
1640 /* If we're trying to delete a prologue or epilogue instruction
1641 that isn't flagged as possibly being dead, something is wrong.
1642 But if we are keeping the stack pointer depressed, we might well
1643 be deleting insns that are used to compute the amount to update
1644 it by, so they are fine. */
1645 if (reload_completed
1646 && !(TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1647 && (TYPE_RETURNS_STACK_DEPRESSED
1648 (TREE_TYPE (current_function_decl
))))
1649 && (((HAVE_epilogue
|| HAVE_prologue
)
1650 && prologue_epilogue_contains (insn
))
1651 || (HAVE_sibcall_epilogue
1652 && sibcall_epilogue_contains (insn
)))
1653 && find_reg_note (insn
, REG_MAYBE_DEAD
, NULL_RTX
) == 0)
1654 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn
);
1656 /* Record sets. Do this even for dead instructions, since they
1657 would have killed the values if they hadn't been deleted. */
1658 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1660 /* CC0 is now known to be dead. Either this insn used it,
1661 in which case it doesn't anymore, or clobbered it,
1662 so the next insn can't use it. */
1665 if (libcall_is_dead
)
1666 prev
= propagate_block_delete_libcall ( insn
, note
);
1668 propagate_block_delete_insn (insn
);
1673 /* See if this is an increment or decrement that can be merged into
1674 a following memory address. */
1677 rtx x
= single_set (insn
);
1679 /* Does this instruction increment or decrement a register? */
1680 if ((flags
& PROP_AUTOINC
)
1682 && GET_CODE (SET_DEST (x
)) == REG
1683 && (GET_CODE (SET_SRC (x
)) == PLUS
1684 || GET_CODE (SET_SRC (x
)) == MINUS
)
1685 && XEXP (SET_SRC (x
), 0) == SET_DEST (x
)
1686 && GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
1687 /* Ok, look for a following memory ref we can combine with.
1688 If one is found, change the memory ref to a PRE_INC
1689 or PRE_DEC, cancel this insn, and return 1.
1690 Return 0 if nothing has been done. */
1691 && try_pre_increment_1 (pbi
, insn
))
1694 #endif /* AUTO_INC_DEC */
1696 CLEAR_REG_SET (pbi
->new_set
);
1698 /* If this is not the final pass, and this insn is copying the value of
1699 a library call and it's dead, don't scan the insns that perform the
1700 library call, so that the call's arguments are not marked live. */
1701 if (libcall_is_dead
)
1703 /* Record the death of the dest reg. */
1704 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1706 insn
= XEXP (note
, 0);
1707 return PREV_INSN (insn
);
1709 else if (GET_CODE (PATTERN (insn
)) == SET
1710 && SET_DEST (PATTERN (insn
)) == stack_pointer_rtx
1711 && GET_CODE (SET_SRC (PATTERN (insn
))) == PLUS
1712 && XEXP (SET_SRC (PATTERN (insn
)), 0) == stack_pointer_rtx
1713 && GET_CODE (XEXP (SET_SRC (PATTERN (insn
)), 1)) == CONST_INT
)
1714 /* We have an insn to pop a constant amount off the stack.
1715 (Such insns use PLUS regardless of the direction of the stack,
1716 and any insn to adjust the stack by a constant is always a pop.)
1717 These insns, if not dead stores, have no effect on life, though
1718 they do have an effect on the memory stores we are tracking. */
1719 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1723 /* Any regs live at the time of a call instruction must not go
1724 in a register clobbered by calls. Find all regs now live and
1725 record this for them. */
1727 if (GET_CODE (insn
) == CALL_INSN
&& (flags
& PROP_REG_INFO
))
1728 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1729 { REG_N_CALLS_CROSSED (i
)++; });
1731 /* Record sets. Do this even for dead instructions, since they
1732 would have killed the values if they hadn't been deleted. */
1733 mark_set_regs (pbi
, PATTERN (insn
), insn
);
1735 if (GET_CODE (insn
) == CALL_INSN
)
1741 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1742 cond
= COND_EXEC_TEST (PATTERN (insn
));
1744 /* Non-constant calls clobber memory, constant calls do not
1745 clobber memory, though they may clobber outgoing arguments
1747 if (! CONST_OR_PURE_CALL_P (insn
))
1749 free_EXPR_LIST_list (&pbi
->mem_set_list
);
1750 pbi
->mem_set_list_len
= 0;
1753 invalidate_mems_from_set (pbi
, stack_pointer_rtx
);
1755 /* There may be extra registers to be clobbered. */
1756 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1758 note
= XEXP (note
, 1))
1759 if (GET_CODE (XEXP (note
, 0)) == CLOBBER
)
1760 mark_set_1 (pbi
, CLOBBER
, XEXP (XEXP (note
, 0), 0),
1761 cond
, insn
, pbi
->flags
);
1763 /* Calls change all call-used and global registers. */
1764 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1765 if (TEST_HARD_REG_BIT (regs_invalidated_by_call
, i
))
1767 /* We do not want REG_UNUSED notes for these registers. */
1768 mark_set_1 (pbi
, CLOBBER
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1770 pbi
->flags
& ~(PROP_DEATH_NOTES
| PROP_REG_INFO
));
1774 /* If an insn doesn't use CC0, it becomes dead since we assume
1775 that every insn clobbers it. So show it dead here;
1776 mark_used_regs will set it live if it is referenced. */
1781 mark_used_regs (pbi
, PATTERN (insn
), NULL_RTX
, insn
);
1782 if ((flags
& PROP_EQUAL_NOTES
)
1783 && ((note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
1784 || (note
= find_reg_note (insn
, REG_EQUIV
, NULL_RTX
))))
1785 mark_used_regs (pbi
, XEXP (note
, 0), NULL_RTX
, insn
);
1787 /* Sometimes we may have inserted something before INSN (such as a move)
1788 when we make an auto-inc. So ensure we will scan those insns. */
1790 prev
= PREV_INSN (insn
);
1793 if (! insn_is_dead
&& GET_CODE (insn
) == CALL_INSN
)
1799 if (GET_CODE (PATTERN (insn
)) == COND_EXEC
)
1800 cond
= COND_EXEC_TEST (PATTERN (insn
));
1802 /* Calls use their arguments. */
1803 for (note
= CALL_INSN_FUNCTION_USAGE (insn
);
1805 note
= XEXP (note
, 1))
1806 if (GET_CODE (XEXP (note
, 0)) == USE
)
1807 mark_used_regs (pbi
, XEXP (XEXP (note
, 0), 0),
1810 /* The stack ptr is used (honorarily) by a CALL insn. */
1811 SET_REGNO_REG_SET (pbi
->reg_live
, STACK_POINTER_REGNUM
);
1813 /* Calls may also reference any of the global registers,
1814 so they are made live. */
1815 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
1817 mark_used_reg (pbi
, gen_rtx_REG (reg_raw_mode
[i
], i
),
1822 /* On final pass, update counts of how many insns in which each reg
1824 if (flags
& PROP_REG_INFO
)
1825 EXECUTE_IF_SET_IN_REG_SET (pbi
->reg_live
, 0, i
,
1826 { REG_LIVE_LENGTH (i
)++; });
1831 /* Initialize a propagate_block_info struct for public consumption.
1832 Note that the structure itself is opaque to this file, but that
1833 the user can use the regsets provided here. */
1835 struct propagate_block_info
*
1836 init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
)
1838 regset live
, local_set
, cond_local_set
;
1841 struct propagate_block_info
*pbi
= xmalloc (sizeof (*pbi
));
1844 pbi
->reg_live
= live
;
1845 pbi
->mem_set_list
= NULL_RTX
;
1846 pbi
->mem_set_list_len
= 0;
1847 pbi
->local_set
= local_set
;
1848 pbi
->cond_local_set
= cond_local_set
;
1852 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
1853 pbi
->reg_next_use
= (rtx
*) xcalloc (max_reg_num (), sizeof (rtx
));
1855 pbi
->reg_next_use
= NULL
;
1857 pbi
->new_set
= BITMAP_XMALLOC ();
1859 #ifdef HAVE_conditional_execution
1860 pbi
->reg_cond_dead
= splay_tree_new (splay_tree_compare_ints
, NULL
,
1861 free_reg_cond_life_info
);
1862 pbi
->reg_cond_reg
= BITMAP_XMALLOC ();
1864 /* If this block ends in a conditional branch, for each register live
1865 from one side of the branch and not the other, record the register
1866 as conditionally dead. */
1867 if (GET_CODE (bb
->end
) == JUMP_INSN
1868 && any_condjump_p (bb
->end
))
1870 regset_head diff_head
;
1871 regset diff
= INITIALIZE_REG_SET (diff_head
);
1872 basic_block bb_true
, bb_false
;
1873 rtx cond_true
, cond_false
, set_src
;
1876 /* Identify the successor blocks. */
1877 bb_true
= bb
->succ
->dest
;
1878 if (bb
->succ
->succ_next
!= NULL
)
1880 bb_false
= bb
->succ
->succ_next
->dest
;
1882 if (bb
->succ
->flags
& EDGE_FALLTHRU
)
1884 basic_block t
= bb_false
;
1888 else if (! (bb
->succ
->succ_next
->flags
& EDGE_FALLTHRU
))
1893 /* This can happen with a conditional jump to the next insn. */
1894 if (JUMP_LABEL (bb
->end
) != bb_true
->head
)
1897 /* Simplest way to do nothing. */
1901 /* Extract the condition from the branch. */
1902 set_src
= SET_SRC (pc_set (bb
->end
));
1903 cond_true
= XEXP (set_src
, 0);
1904 cond_false
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true
)),
1905 GET_MODE (cond_true
), XEXP (cond_true
, 0),
1906 XEXP (cond_true
, 1));
1907 if (GET_CODE (XEXP (set_src
, 1)) == PC
)
1910 cond_false
= cond_true
;
1914 /* Compute which register lead different lives in the successors. */
1915 if (bitmap_operation (diff
, bb_true
->global_live_at_start
,
1916 bb_false
->global_live_at_start
, BITMAP_XOR
))
1918 rtx reg
= XEXP (cond_true
, 0);
1920 if (GET_CODE (reg
) == SUBREG
)
1921 reg
= SUBREG_REG (reg
);
1923 if (GET_CODE (reg
) != REG
)
1926 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (reg
));
1928 /* For each such register, mark it conditionally dead. */
1929 EXECUTE_IF_SET_IN_REG_SET
1932 struct reg_cond_life_info
*rcli
;
1935 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
1937 if (REGNO_REG_SET_P (bb_true
->global_live_at_start
, i
))
1941 rcli
->condition
= cond
;
1942 rcli
->stores
= const0_rtx
;
1943 rcli
->orig_condition
= cond
;
1945 splay_tree_insert (pbi
->reg_cond_dead
, i
,
1946 (splay_tree_value
) rcli
);
1950 FREE_REG_SET (diff
);
1954 /* If this block has no successors, any stores to the frame that aren't
1955 used later in the block are dead. So make a pass over the block
1956 recording any such that are made and show them dead at the end. We do
1957 a very conservative and simple job here. */
1959 && ! (TREE_CODE (TREE_TYPE (current_function_decl
)) == FUNCTION_TYPE
1960 && (TYPE_RETURNS_STACK_DEPRESSED
1961 (TREE_TYPE (current_function_decl
))))
1962 && (flags
& PROP_SCAN_DEAD_CODE
)
1963 && (bb
->succ
== NULL
1964 || (bb
->succ
->succ_next
== NULL
1965 && bb
->succ
->dest
== EXIT_BLOCK_PTR
1966 && ! current_function_calls_eh_return
)))
1969 for (insn
= bb
->end
; insn
!= bb
->head
; insn
= PREV_INSN (insn
))
1970 if (GET_CODE (insn
) == INSN
1971 && (set
= single_set (insn
))
1972 && GET_CODE (SET_DEST (set
)) == MEM
)
1974 rtx mem
= SET_DEST (set
);
1975 rtx canon_mem
= canon_rtx (mem
);
1977 /* This optimization is performed by faking a store to the
1978 memory at the end of the block. This doesn't work for
1979 unchanging memories because multiple stores to unchanging
1980 memory is illegal and alias analysis doesn't consider it. */
1981 if (RTX_UNCHANGING_P (canon_mem
))
1984 if (XEXP (canon_mem
, 0) == frame_pointer_rtx
1985 || (GET_CODE (XEXP (canon_mem
, 0)) == PLUS
1986 && XEXP (XEXP (canon_mem
, 0), 0) == frame_pointer_rtx
1987 && GET_CODE (XEXP (XEXP (canon_mem
, 0), 1)) == CONST_INT
))
1988 add_to_mem_set_list (pbi
, canon_mem
);
1995 /* Release a propagate_block_info struct. */
1998 free_propagate_block_info (pbi
)
1999 struct propagate_block_info
*pbi
;
2001 free_EXPR_LIST_list (&pbi
->mem_set_list
);
2003 BITMAP_XFREE (pbi
->new_set
);
2005 #ifdef HAVE_conditional_execution
2006 splay_tree_delete (pbi
->reg_cond_dead
);
2007 BITMAP_XFREE (pbi
->reg_cond_reg
);
2010 if (pbi
->reg_next_use
)
2011 free (pbi
->reg_next_use
);
2016 /* Compute the registers live at the beginning of a basic block BB from
2017 those live at the end.
2019 When called, REG_LIVE contains those live at the end. On return, it
2020 contains those live at the beginning.
2022 LOCAL_SET, if non-null, will be set with all registers killed
2023 unconditionally by this basic block.
2024 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2025 killed conditionally by this basic block. If there is any unconditional
2026 set of a register, then the corresponding bit will be set in LOCAL_SET
2027 and cleared in COND_LOCAL_SET.
2028 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2029 case, the resulting set will be equal to the union of the two sets that
2030 would otherwise be computed.
2032 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2035 propagate_block (bb
, live
, local_set
, cond_local_set
, flags
)
2039 regset cond_local_set
;
2042 struct propagate_block_info
*pbi
;
2046 pbi
= init_propagate_block_info (bb
, live
, local_set
, cond_local_set
, flags
);
2048 if (flags
& PROP_REG_INFO
)
2052 /* Process the regs live at the end of the block.
2053 Mark them as not local to any one basic block. */
2054 EXECUTE_IF_SET_IN_REG_SET (live
, 0, i
,
2055 { REG_BASIC_BLOCK (i
) = REG_BLOCK_GLOBAL
; });
2058 /* Scan the block an insn at a time from end to beginning. */
2061 for (insn
= bb
->end
;; insn
= prev
)
2063 /* If this is a call to `setjmp' et al, warn if any
2064 non-volatile datum is live. */
2065 if ((flags
& PROP_REG_INFO
)
2066 && GET_CODE (insn
) == CALL_INSN
2067 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2068 IOR_REG_SET (regs_live_at_setjmp
, pbi
->reg_live
);
2070 prev
= propagate_one_insn (pbi
, insn
);
2071 changed
|= NEXT_INSN (prev
) != insn
;
2073 if (insn
== bb
->head
)
2077 free_propagate_block_info (pbi
);
2082 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2083 (SET expressions whose destinations are registers dead after the insn).
2084 NEEDED is the regset that says which regs are alive after the insn.
2086 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2088 If X is the entire body of an insn, NOTES contains the reg notes
2089 pertaining to the insn. */
2092 insn_dead_p (pbi
, x
, call_ok
, notes
)
2093 struct propagate_block_info
*pbi
;
2096 rtx notes ATTRIBUTE_UNUSED
;
2098 enum rtx_code code
= GET_CODE (x
);
2101 /* As flow is invoked after combine, we must take existing AUTO_INC
2102 expressions into account. */
2103 for (; notes
; notes
= XEXP (notes
, 1))
2105 if (REG_NOTE_KIND (notes
) == REG_INC
)
2107 int regno
= REGNO (XEXP (notes
, 0));
2109 /* Don't delete insns to set global regs. */
2110 if ((regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2111 || REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2117 /* If setting something that's a reg or part of one,
2118 see if that register's altered value will be live. */
2122 rtx r
= SET_DEST (x
);
2125 if (GET_CODE (r
) == CC0
)
2126 return ! pbi
->cc0_live
;
2129 /* A SET that is a subroutine call cannot be dead. */
2130 if (GET_CODE (SET_SRC (x
)) == CALL
)
2136 /* Don't eliminate loads from volatile memory or volatile asms. */
2137 else if (volatile_refs_p (SET_SRC (x
)))
2140 if (GET_CODE (r
) == MEM
)
2144 if (MEM_VOLATILE_P (r
) || GET_MODE (r
) == BLKmode
)
2147 canon_r
= canon_rtx (r
);
2149 /* Walk the set of memory locations we are currently tracking
2150 and see if one is an identical match to this memory location.
2151 If so, this memory write is dead (remember, we're walking
2152 backwards from the end of the block to the start). Since
2153 rtx_equal_p does not check the alias set or flags, we also
2154 must have the potential for them to conflict (anti_dependence). */
2155 for (temp
= pbi
->mem_set_list
; temp
!= 0; temp
= XEXP (temp
, 1))
2156 if (anti_dependence (r
, XEXP (temp
, 0)))
2158 rtx mem
= XEXP (temp
, 0);
2160 if (rtx_equal_p (XEXP (canon_r
, 0), XEXP (mem
, 0))
2161 && (GET_MODE_SIZE (GET_MODE (canon_r
))
2162 <= GET_MODE_SIZE (GET_MODE (mem
))))
2166 /* Check if memory reference matches an auto increment. Only
2167 post increment/decrement or modify are valid. */
2168 if (GET_MODE (mem
) == GET_MODE (r
)
2169 && (GET_CODE (XEXP (mem
, 0)) == POST_DEC
2170 || GET_CODE (XEXP (mem
, 0)) == POST_INC
2171 || GET_CODE (XEXP (mem
, 0)) == POST_MODIFY
)
2172 && GET_MODE (XEXP (mem
, 0)) == GET_MODE (r
)
2173 && rtx_equal_p (XEXP (XEXP (mem
, 0), 0), XEXP (r
, 0)))
2180 while (GET_CODE (r
) == SUBREG
2181 || GET_CODE (r
) == STRICT_LOW_PART
2182 || GET_CODE (r
) == ZERO_EXTRACT
)
2185 if (GET_CODE (r
) == REG
)
2187 int regno
= REGNO (r
);
2190 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
))
2193 /* If this is a hard register, verify that subsequent
2194 words are not needed. */
2195 if (regno
< FIRST_PSEUDO_REGISTER
)
2197 int n
= HARD_REGNO_NREGS (regno
, GET_MODE (r
));
2200 if (REGNO_REG_SET_P (pbi
->reg_live
, regno
+n
))
2204 /* Don't delete insns to set global regs. */
2205 if (regno
< FIRST_PSEUDO_REGISTER
&& global_regs
[regno
])
2208 /* Make sure insns to set the stack pointer aren't deleted. */
2209 if (regno
== STACK_POINTER_REGNUM
)
2212 /* ??? These bits might be redundant with the force live bits
2213 in calculate_global_regs_live. We would delete from
2214 sequential sets; whether this actually affects real code
2215 for anything but the stack pointer I don't know. */
2216 /* Make sure insns to set the frame pointer aren't deleted. */
2217 if (regno
== FRAME_POINTER_REGNUM
2218 && (! reload_completed
|| frame_pointer_needed
))
2220 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2221 if (regno
== HARD_FRAME_POINTER_REGNUM
2222 && (! reload_completed
|| frame_pointer_needed
))
2226 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2227 /* Make sure insns to set arg pointer are never deleted
2228 (if the arg pointer isn't fixed, there will be a USE
2229 for it, so we can treat it normally). */
2230 if (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
2234 /* Otherwise, the set is dead. */
2240 /* If performing several activities, insn is dead if each activity
2241 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2242 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2244 else if (code
== PARALLEL
)
2246 int i
= XVECLEN (x
, 0);
2248 for (i
--; i
>= 0; i
--)
2249 if (GET_CODE (XVECEXP (x
, 0, i
)) != CLOBBER
2250 && GET_CODE (XVECEXP (x
, 0, i
)) != USE
2251 && ! insn_dead_p (pbi
, XVECEXP (x
, 0, i
), call_ok
, NULL_RTX
))
2257 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2258 is not necessarily true for hard registers. */
2259 else if (code
== CLOBBER
&& GET_CODE (XEXP (x
, 0)) == REG
2260 && REGNO (XEXP (x
, 0)) >= FIRST_PSEUDO_REGISTER
2261 && ! REGNO_REG_SET_P (pbi
->reg_live
, REGNO (XEXP (x
, 0))))
2264 /* We do not check other CLOBBER or USE here. An insn consisting of just
2265 a CLOBBER or just a USE should not be deleted. */
2269 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2270 return 1 if the entire library call is dead.
2271 This is true if INSN copies a register (hard or pseudo)
2272 and if the hard return reg of the call insn is dead.
2273 (The caller should have tested the destination of the SET inside
2274 INSN already for death.)
2276 If this insn doesn't just copy a register, then we don't
2277 have an ordinary libcall. In that case, cse could not have
2278 managed to substitute the source for the dest later on,
2279 so we can assume the libcall is dead.
2281 PBI is the block info giving pseudoregs live before this insn.
2282 NOTE is the REG_RETVAL note of the insn. */
2285 libcall_dead_p (pbi
, note
, insn
)
2286 struct propagate_block_info
*pbi
;
2290 rtx x
= single_set (insn
);
2294 rtx r
= SET_SRC (x
);
2296 if (GET_CODE (r
) == REG
)
2298 rtx call
= XEXP (note
, 0);
2302 /* Find the call insn. */
2303 while (call
!= insn
&& GET_CODE (call
) != CALL_INSN
)
2304 call
= NEXT_INSN (call
);
2306 /* If there is none, do nothing special,
2307 since ordinary death handling can understand these insns. */
2311 /* See if the hard reg holding the value is dead.
2312 If this is a PARALLEL, find the call within it. */
2313 call_pat
= PATTERN (call
);
2314 if (GET_CODE (call_pat
) == PARALLEL
)
2316 for (i
= XVECLEN (call_pat
, 0) - 1; i
>= 0; i
--)
2317 if (GET_CODE (XVECEXP (call_pat
, 0, i
)) == SET
2318 && GET_CODE (SET_SRC (XVECEXP (call_pat
, 0, i
))) == CALL
)
2321 /* This may be a library call that is returning a value
2322 via invisible pointer. Do nothing special, since
2323 ordinary death handling can understand these insns. */
2327 call_pat
= XVECEXP (call_pat
, 0, i
);
2330 return insn_dead_p (pbi
, call_pat
, 1, REG_NOTES (call
));
2336 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2337 live at function entry. Don't count global register variables, variables
2338 in registers that can be used for function arg passing, or variables in
2339 fixed hard registers. */
2342 regno_uninitialized (regno
)
2345 if (n_basic_blocks
== 0
2346 || (regno
< FIRST_PSEUDO_REGISTER
2347 && (global_regs
[regno
]
2348 || fixed_regs
[regno
]
2349 || FUNCTION_ARG_REGNO_P (regno
))))
2352 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
);
2355 /* 1 if register REGNO was alive at a place where `setjmp' was called
2356 and was set more than once or is an argument.
2357 Such regs may be clobbered by `longjmp'. */
2360 regno_clobbered_at_setjmp (regno
)
2363 if (n_basic_blocks
== 0)
2366 return ((REG_N_SETS (regno
) > 1
2367 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR
->next_bb
->global_live_at_start
, regno
))
2368 && REGNO_REG_SET_P (regs_live_at_setjmp
, regno
));
2371 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2372 maximal list size; look for overlaps in mode and select the largest. */
2374 add_to_mem_set_list (pbi
, mem
)
2375 struct propagate_block_info
*pbi
;
2380 /* We don't know how large a BLKmode store is, so we must not
2381 take them into consideration. */
2382 if (GET_MODE (mem
) == BLKmode
)
2385 for (i
= pbi
->mem_set_list
; i
; i
= XEXP (i
, 1))
2387 rtx e
= XEXP (i
, 0);
2388 if (rtx_equal_p (XEXP (mem
, 0), XEXP (e
, 0)))
2390 if (GET_MODE_SIZE (GET_MODE (mem
)) > GET_MODE_SIZE (GET_MODE (e
)))
2393 /* If we must store a copy of the mem, we can just modify
2394 the mode of the stored copy. */
2395 if (pbi
->flags
& PROP_AUTOINC
)
2396 PUT_MODE (e
, GET_MODE (mem
));
2405 if (pbi
->mem_set_list_len
< MAX_MEM_SET_LIST_LEN
)
2408 /* Store a copy of mem, otherwise the address may be
2409 scrogged by find_auto_inc. */
2410 if (pbi
->flags
& PROP_AUTOINC
)
2411 mem
= shallow_copy_rtx (mem
);
2413 pbi
->mem_set_list
= alloc_EXPR_LIST (0, mem
, pbi
->mem_set_list
);
2414 pbi
->mem_set_list_len
++;
2418 /* INSN references memory, possibly using autoincrement addressing modes.
2419 Find any entries on the mem_set_list that need to be invalidated due
2420 to an address change. */
2423 invalidate_mems_from_autoinc (px
, data
)
2428 struct propagate_block_info
*pbi
= data
;
2430 if (GET_RTX_CLASS (GET_CODE (x
)) == 'a')
2432 invalidate_mems_from_set (pbi
, XEXP (x
, 0));
2439 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2442 invalidate_mems_from_set (pbi
, exp
)
2443 struct propagate_block_info
*pbi
;
2446 rtx temp
= pbi
->mem_set_list
;
2447 rtx prev
= NULL_RTX
;
2452 next
= XEXP (temp
, 1);
2453 if (reg_overlap_mentioned_p (exp
, XEXP (temp
, 0)))
2455 /* Splice this entry out of the list. */
2457 XEXP (prev
, 1) = next
;
2459 pbi
->mem_set_list
= next
;
2460 free_EXPR_LIST_node (temp
);
2461 pbi
->mem_set_list_len
--;
2469 /* Process the registers that are set within X. Their bits are set to
2470 1 in the regset DEAD, because they are dead prior to this insn.
2472 If INSN is nonzero, it is the insn being processed.
2474 FLAGS is the set of operations to perform. */
2477 mark_set_regs (pbi
, x
, insn
)
2478 struct propagate_block_info
*pbi
;
2481 rtx cond
= NULL_RTX
;
2486 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2488 if (REG_NOTE_KIND (link
) == REG_INC
)
2489 mark_set_1 (pbi
, SET
, XEXP (link
, 0),
2490 (GET_CODE (x
) == COND_EXEC
2491 ? COND_EXEC_TEST (x
) : NULL_RTX
),
2495 switch (code
= GET_CODE (x
))
2499 mark_set_1 (pbi
, code
, SET_DEST (x
), cond
, insn
, pbi
->flags
);
2503 cond
= COND_EXEC_TEST (x
);
2504 x
= COND_EXEC_CODE (x
);
2511 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2513 rtx sub
= XVECEXP (x
, 0, i
);
2514 switch (code
= GET_CODE (sub
))
2517 if (cond
!= NULL_RTX
)
2520 cond
= COND_EXEC_TEST (sub
);
2521 sub
= COND_EXEC_CODE (sub
);
2522 if (GET_CODE (sub
) != SET
&& GET_CODE (sub
) != CLOBBER
)
2528 mark_set_1 (pbi
, code
, SET_DEST (sub
), cond
, insn
, pbi
->flags
);
2543 /* Process a single set, which appears in INSN. REG (which may not
2544 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2545 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2546 If the set is conditional (because it appear in a COND_EXEC), COND
2547 will be the condition. */
2550 mark_set_1 (pbi
, code
, reg
, cond
, insn
, flags
)
2551 struct propagate_block_info
*pbi
;
2553 rtx reg
, cond
, insn
;
2556 int regno_first
= -1, regno_last
= -1;
2557 unsigned long not_dead
= 0;
2560 /* Modifying just one hardware register of a multi-reg value or just a
2561 byte field of a register does not mean the value from before this insn
2562 is now dead. Of course, if it was dead after it's unused now. */
2564 switch (GET_CODE (reg
))
2567 /* Some targets place small structures in registers for return values of
2568 functions. We have to detect this case specially here to get correct
2569 flow information. */
2570 for (i
= XVECLEN (reg
, 0) - 1; i
>= 0; i
--)
2571 if (XEXP (XVECEXP (reg
, 0, i
), 0) != 0)
2572 mark_set_1 (pbi
, code
, XEXP (XVECEXP (reg
, 0, i
), 0), cond
, insn
,
2578 case STRICT_LOW_PART
:
2579 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2581 reg
= XEXP (reg
, 0);
2582 while (GET_CODE (reg
) == SUBREG
2583 || GET_CODE (reg
) == ZERO_EXTRACT
2584 || GET_CODE (reg
) == SIGN_EXTRACT
2585 || GET_CODE (reg
) == STRICT_LOW_PART
);
2586 if (GET_CODE (reg
) == MEM
)
2588 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
, REGNO (reg
));
2592 regno_last
= regno_first
= REGNO (reg
);
2593 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2594 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
2598 if (GET_CODE (SUBREG_REG (reg
)) == REG
)
2600 enum machine_mode outer_mode
= GET_MODE (reg
);
2601 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (reg
));
2603 /* Identify the range of registers affected. This is moderately
2604 tricky for hard registers. See alter_subreg. */
2606 regno_last
= regno_first
= REGNO (SUBREG_REG (reg
));
2607 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2609 regno_first
+= subreg_regno_offset (regno_first
, inner_mode
,
2612 regno_last
= (regno_first
2613 + HARD_REGNO_NREGS (regno_first
, outer_mode
) - 1);
2615 /* Since we've just adjusted the register number ranges, make
2616 sure REG matches. Otherwise some_was_live will be clear
2617 when it shouldn't have been, and we'll create incorrect
2618 REG_UNUSED notes. */
2619 reg
= gen_rtx_REG (outer_mode
, regno_first
);
2623 /* If the number of words in the subreg is less than the number
2624 of words in the full register, we have a well-defined partial
2625 set. Otherwise the high bits are undefined.
2627 This is only really applicable to pseudos, since we just took
2628 care of multi-word hard registers. */
2629 if (((GET_MODE_SIZE (outer_mode
)
2630 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
2631 < ((GET_MODE_SIZE (inner_mode
)
2632 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
2633 not_dead
= (unsigned long) REGNO_REG_SET_P (pbi
->reg_live
,
2636 reg
= SUBREG_REG (reg
);
2640 reg
= SUBREG_REG (reg
);
2647 /* If this set is a MEM, then it kills any aliased writes.
2648 If this set is a REG, then it kills any MEMs which use the reg. */
2649 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
2651 if (GET_CODE (reg
) == REG
)
2652 invalidate_mems_from_set (pbi
, reg
);
2654 /* If the memory reference had embedded side effects (autoincrement
2655 address modes. Then we may need to kill some entries on the
2657 if (insn
&& GET_CODE (reg
) == MEM
)
2658 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
2660 if (GET_CODE (reg
) == MEM
&& ! side_effects_p (reg
)
2661 /* ??? With more effort we could track conditional memory life. */
2663 add_to_mem_set_list (pbi
, canon_rtx (reg
));
2666 if (GET_CODE (reg
) == REG
2667 && ! (regno_first
== FRAME_POINTER_REGNUM
2668 && (! reload_completed
|| frame_pointer_needed
))
2669 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2670 && ! (regno_first
== HARD_FRAME_POINTER_REGNUM
2671 && (! reload_completed
|| frame_pointer_needed
))
2673 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2674 && ! (regno_first
== ARG_POINTER_REGNUM
&& fixed_regs
[regno_first
])
2678 int some_was_live
= 0, some_was_dead
= 0;
2680 for (i
= regno_first
; i
<= regno_last
; ++i
)
2682 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
2685 /* Order of the set operation matters here since both
2686 sets may be the same. */
2687 CLEAR_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2688 if (cond
!= NULL_RTX
2689 && ! REGNO_REG_SET_P (pbi
->local_set
, i
))
2690 SET_REGNO_REG_SET (pbi
->cond_local_set
, i
);
2692 SET_REGNO_REG_SET (pbi
->local_set
, i
);
2694 if (code
!= CLOBBER
)
2695 SET_REGNO_REG_SET (pbi
->new_set
, i
);
2697 some_was_live
|= needed_regno
;
2698 some_was_dead
|= ! needed_regno
;
2701 #ifdef HAVE_conditional_execution
2702 /* Consider conditional death in deciding that the register needs
2704 if (some_was_live
&& ! not_dead
2705 /* The stack pointer is never dead. Well, not strictly true,
2706 but it's very difficult to tell from here. Hopefully
2707 combine_stack_adjustments will fix up the most egregious
2709 && regno_first
!= STACK_POINTER_REGNUM
)
2711 for (i
= regno_first
; i
<= regno_last
; ++i
)
2712 if (! mark_regno_cond_dead (pbi
, i
, cond
))
2713 not_dead
|= ((unsigned long) 1) << (i
- regno_first
);
2717 /* Additional data to record if this is the final pass. */
2718 if (flags
& (PROP_LOG_LINKS
| PROP_REG_INFO
2719 | PROP_DEATH_NOTES
| PROP_AUTOINC
))
2722 int blocknum
= pbi
->bb
->index
;
2725 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2727 y
= pbi
->reg_next_use
[regno_first
];
2729 /* The next use is no longer next, since a store intervenes. */
2730 for (i
= regno_first
; i
<= regno_last
; ++i
)
2731 pbi
->reg_next_use
[i
] = 0;
2734 if (flags
& PROP_REG_INFO
)
2736 for (i
= regno_first
; i
<= regno_last
; ++i
)
2738 /* Count (weighted) references, stores, etc. This counts a
2739 register twice if it is modified, but that is correct. */
2740 REG_N_SETS (i
) += 1;
2741 REG_N_REFS (i
) += 1;
2742 REG_FREQ (i
) += REG_FREQ_FROM_BB (pbi
->bb
);
2744 /* The insns where a reg is live are normally counted
2745 elsewhere, but we want the count to include the insn
2746 where the reg is set, and the normal counting mechanism
2747 would not count it. */
2748 REG_LIVE_LENGTH (i
) += 1;
2751 /* If this is a hard reg, record this function uses the reg. */
2752 if (regno_first
< FIRST_PSEUDO_REGISTER
)
2754 for (i
= regno_first
; i
<= regno_last
; i
++)
2755 regs_ever_live
[i
] = 1;
2759 /* Keep track of which basic blocks each reg appears in. */
2760 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
2761 REG_BASIC_BLOCK (regno_first
) = blocknum
;
2762 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
2763 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
2767 if (! some_was_dead
)
2769 if (flags
& PROP_LOG_LINKS
)
2771 /* Make a logical link from the next following insn
2772 that uses this register, back to this insn.
2773 The following insns have already been processed.
2775 We don't build a LOG_LINK for hard registers containing
2776 in ASM_OPERANDs. If these registers get replaced,
2777 we might wind up changing the semantics of the insn,
2778 even if reload can make what appear to be valid
2779 assignments later. */
2780 if (y
&& (BLOCK_NUM (y
) == blocknum
)
2781 && (regno_first
>= FIRST_PSEUDO_REGISTER
2782 || asm_noperands (PATTERN (y
)) < 0))
2783 LOG_LINKS (y
) = alloc_INSN_LIST (insn
, LOG_LINKS (y
));
2788 else if (! some_was_live
)
2790 if (flags
& PROP_REG_INFO
)
2791 REG_N_DEATHS (regno_first
) += 1;
2793 if (flags
& PROP_DEATH_NOTES
)
2795 /* Note that dead stores have already been deleted
2796 when possible. If we get here, we have found a
2797 dead store that cannot be eliminated (because the
2798 same insn does something useful). Indicate this
2799 by marking the reg being set as dying here. */
2801 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2806 if (flags
& PROP_DEATH_NOTES
)
2808 /* This is a case where we have a multi-word hard register
2809 and some, but not all, of the words of the register are
2810 needed in subsequent insns. Write REG_UNUSED notes
2811 for those parts that were not needed. This case should
2814 for (i
= regno_first
; i
<= regno_last
; ++i
)
2815 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
))
2817 = alloc_EXPR_LIST (REG_UNUSED
,
2818 gen_rtx_REG (reg_raw_mode
[i
], i
),
2824 /* Mark the register as being dead. */
2826 /* The stack pointer is never dead. Well, not strictly true,
2827 but it's very difficult to tell from here. Hopefully
2828 combine_stack_adjustments will fix up the most egregious
2830 && regno_first
!= STACK_POINTER_REGNUM
)
2832 for (i
= regno_first
; i
<= regno_last
; ++i
)
2833 if (!(not_dead
& (((unsigned long) 1) << (i
- regno_first
))))
2834 CLEAR_REGNO_REG_SET (pbi
->reg_live
, i
);
2837 else if (GET_CODE (reg
) == REG
)
2839 if (flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
2840 pbi
->reg_next_use
[regno_first
] = 0;
2843 /* If this is the last pass and this is a SCRATCH, show it will be dying
2844 here and count it. */
2845 else if (GET_CODE (reg
) == SCRATCH
)
2847 if (flags
& PROP_DEATH_NOTES
)
2849 = alloc_EXPR_LIST (REG_UNUSED
, reg
, REG_NOTES (insn
));
2853 #ifdef HAVE_conditional_execution
2854 /* Mark REGNO conditionally dead.
2855 Return true if the register is now unconditionally dead. */
2858 mark_regno_cond_dead (pbi
, regno
, cond
)
2859 struct propagate_block_info
*pbi
;
2863 /* If this is a store to a predicate register, the value of the
2864 predicate is changing, we don't know that the predicate as seen
2865 before is the same as that seen after. Flush all dependent
2866 conditions from reg_cond_dead. This will make all such
2867 conditionally live registers unconditionally live. */
2868 if (REGNO_REG_SET_P (pbi
->reg_cond_reg
, regno
))
2869 flush_reg_cond_reg (pbi
, regno
);
2871 /* If this is an unconditional store, remove any conditional
2872 life that may have existed. */
2873 if (cond
== NULL_RTX
)
2874 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2877 splay_tree_node node
;
2878 struct reg_cond_life_info
*rcli
;
2881 /* Otherwise this is a conditional set. Record that fact.
2882 It may have been conditionally used, or there may be a
2883 subsequent set with a complimentary condition. */
2885 node
= splay_tree_lookup (pbi
->reg_cond_dead
, regno
);
2888 /* The register was unconditionally live previously.
2889 Record the current condition as the condition under
2890 which it is dead. */
2891 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
2892 rcli
->condition
= cond
;
2893 rcli
->stores
= cond
;
2894 rcli
->orig_condition
= const0_rtx
;
2895 splay_tree_insert (pbi
->reg_cond_dead
, regno
,
2896 (splay_tree_value
) rcli
);
2898 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2900 /* Not unconditionally dead. */
2905 /* The register was conditionally live previously.
2906 Add the new condition to the old. */
2907 rcli
= (struct reg_cond_life_info
*) node
->value
;
2908 ncond
= rcli
->condition
;
2909 ncond
= ior_reg_cond (ncond
, cond
, 1);
2910 if (rcli
->stores
== const0_rtx
)
2911 rcli
->stores
= cond
;
2912 else if (rcli
->stores
!= const1_rtx
)
2913 rcli
->stores
= ior_reg_cond (rcli
->stores
, cond
, 1);
2915 /* If the register is now unconditionally dead, remove the entry
2916 in the splay_tree. A register is unconditionally dead if the
2917 dead condition ncond is true. A register is also unconditionally
2918 dead if the sum of all conditional stores is an unconditional
2919 store (stores is true), and the dead condition is identically the
2920 same as the original dead condition initialized at the end of
2921 the block. This is a pointer compare, not an rtx_equal_p
2923 if (ncond
== const1_rtx
2924 || (ncond
== rcli
->orig_condition
&& rcli
->stores
== const1_rtx
))
2925 splay_tree_remove (pbi
->reg_cond_dead
, regno
);
2928 rcli
->condition
= ncond
;
2930 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
2932 /* Not unconditionally dead. */
2941 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2944 free_reg_cond_life_info (value
)
2945 splay_tree_value value
;
2947 struct reg_cond_life_info
*rcli
= (struct reg_cond_life_info
*) value
;
2951 /* Helper function for flush_reg_cond_reg. */
2954 flush_reg_cond_reg_1 (node
, data
)
2955 splay_tree_node node
;
2958 struct reg_cond_life_info
*rcli
;
2959 int *xdata
= (int *) data
;
2960 unsigned int regno
= xdata
[0];
2962 /* Don't need to search if last flushed value was farther on in
2963 the in-order traversal. */
2964 if (xdata
[1] >= (int) node
->key
)
2967 /* Splice out portions of the expression that refer to regno. */
2968 rcli
= (struct reg_cond_life_info
*) node
->value
;
2969 rcli
->condition
= elim_reg_cond (rcli
->condition
, regno
);
2970 if (rcli
->stores
!= const0_rtx
&& rcli
->stores
!= const1_rtx
)
2971 rcli
->stores
= elim_reg_cond (rcli
->stores
, regno
);
2973 /* If the entire condition is now false, signal the node to be removed. */
2974 if (rcli
->condition
== const0_rtx
)
2976 xdata
[1] = node
->key
;
2979 else if (rcli
->condition
== const1_rtx
)
2985 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2988 flush_reg_cond_reg (pbi
, regno
)
2989 struct propagate_block_info
*pbi
;
2996 while (splay_tree_foreach (pbi
->reg_cond_dead
,
2997 flush_reg_cond_reg_1
, pair
) == -1)
2998 splay_tree_remove (pbi
->reg_cond_dead
, pair
[1]);
3000 CLEAR_REGNO_REG_SET (pbi
->reg_cond_reg
, regno
);
3003 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3004 For ior/and, the ADD flag determines whether we want to add the new
3005 condition X to the old one unconditionally. If it is zero, we will
3006 only return a new expression if X allows us to simplify part of
3007 OLD, otherwise we return NULL to the caller.
3008 If ADD is nonzero, we will return a new condition in all cases. The
3009 toplevel caller of one of these functions should always pass 1 for
3013 ior_reg_cond (old
, x
, add
)
3019 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3021 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3022 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x
), GET_CODE (old
))
3023 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3025 if (GET_CODE (x
) == GET_CODE (old
)
3026 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3030 return gen_rtx_IOR (0, old
, x
);
3033 switch (GET_CODE (old
))
3036 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3037 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3038 if (op0
!= NULL
|| op1
!= NULL
)
3040 if (op0
== const0_rtx
)
3041 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3042 if (op1
== const0_rtx
)
3043 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3044 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3047 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3048 else if (rtx_equal_p (x
, op0
))
3049 /* (x | A) | x ~ (x | A). */
3052 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3053 else if (rtx_equal_p (x
, op1
))
3054 /* (A | x) | x ~ (A | x). */
3056 return gen_rtx_IOR (0, op0
, op1
);
3060 return gen_rtx_IOR (0, old
, x
);
3063 op0
= ior_reg_cond (XEXP (old
, 0), x
, 0);
3064 op1
= ior_reg_cond (XEXP (old
, 1), x
, 0);
3065 if (op0
!= NULL
|| op1
!= NULL
)
3067 if (op0
== const1_rtx
)
3068 return op1
? op1
: gen_rtx_IOR (0, XEXP (old
, 1), x
);
3069 if (op1
== const1_rtx
)
3070 return op0
? op0
: gen_rtx_IOR (0, XEXP (old
, 0), x
);
3071 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3074 op0
= gen_rtx_IOR (0, XEXP (old
, 0), x
);
3075 else if (rtx_equal_p (x
, op0
))
3076 /* (x & A) | x ~ x. */
3079 op1
= gen_rtx_IOR (0, XEXP (old
, 1), x
);
3080 else if (rtx_equal_p (x
, op1
))
3081 /* (A & x) | x ~ x. */
3083 return gen_rtx_AND (0, op0
, op1
);
3087 return gen_rtx_IOR (0, old
, x
);
3090 op0
= and_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3092 return not_reg_cond (op0
);
3095 return gen_rtx_IOR (0, old
, x
);
3106 enum rtx_code x_code
;
3108 if (x
== const0_rtx
)
3110 else if (x
== const1_rtx
)
3112 x_code
= GET_CODE (x
);
3115 if (GET_RTX_CLASS (x_code
) == '<'
3116 && GET_CODE (XEXP (x
, 0)) == REG
)
3118 if (XEXP (x
, 1) != const0_rtx
)
3121 return gen_rtx_fmt_ee (reverse_condition (x_code
),
3122 VOIDmode
, XEXP (x
, 0), const0_rtx
);
3124 return gen_rtx_NOT (0, x
);
3128 and_reg_cond (old
, x
, add
)
3134 if (GET_RTX_CLASS (GET_CODE (old
)) == '<')
3136 if (GET_RTX_CLASS (GET_CODE (x
)) == '<'
3137 && GET_CODE (x
) == reverse_condition (GET_CODE (old
))
3138 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3140 if (GET_CODE (x
) == GET_CODE (old
)
3141 && REGNO (XEXP (x
, 0)) == REGNO (XEXP (old
, 0)))
3145 return gen_rtx_AND (0, old
, x
);
3148 switch (GET_CODE (old
))
3151 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3152 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3153 if (op0
!= NULL
|| op1
!= NULL
)
3155 if (op0
== const0_rtx
)
3156 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3157 if (op1
== const0_rtx
)
3158 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3159 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3162 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3163 else if (rtx_equal_p (x
, op0
))
3164 /* (x | A) & x ~ x. */
3167 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3168 else if (rtx_equal_p (x
, op1
))
3169 /* (A | x) & x ~ x. */
3171 return gen_rtx_IOR (0, op0
, op1
);
3175 return gen_rtx_AND (0, old
, x
);
3178 op0
= and_reg_cond (XEXP (old
, 0), x
, 0);
3179 op1
= and_reg_cond (XEXP (old
, 1), x
, 0);
3180 if (op0
!= NULL
|| op1
!= NULL
)
3182 if (op0
== const1_rtx
)
3183 return op1
? op1
: gen_rtx_AND (0, XEXP (old
, 1), x
);
3184 if (op1
== const1_rtx
)
3185 return op0
? op0
: gen_rtx_AND (0, XEXP (old
, 0), x
);
3186 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3189 op0
= gen_rtx_AND (0, XEXP (old
, 0), x
);
3190 else if (rtx_equal_p (x
, op0
))
3191 /* (x & A) & x ~ (x & A). */
3194 op1
= gen_rtx_AND (0, XEXP (old
, 1), x
);
3195 else if (rtx_equal_p (x
, op1
))
3196 /* (A & x) & x ~ (A & x). */
3198 return gen_rtx_AND (0, op0
, op1
);
3202 return gen_rtx_AND (0, old
, x
);
3205 op0
= ior_reg_cond (XEXP (old
, 0), not_reg_cond (x
), 0);
3207 return not_reg_cond (op0
);
3210 return gen_rtx_AND (0, old
, x
);
3217 /* Given a condition X, remove references to reg REGNO and return the
3218 new condition. The removal will be done so that all conditions
3219 involving REGNO are considered to evaluate to false. This function
3220 is used when the value of REGNO changes. */
3223 elim_reg_cond (x
, regno
)
3229 if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
3231 if (REGNO (XEXP (x
, 0)) == regno
)
3236 switch (GET_CODE (x
))
3239 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3240 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3241 if (op0
== const0_rtx
|| op1
== const0_rtx
)
3243 if (op0
== const1_rtx
)
3245 if (op1
== const1_rtx
)
3247 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3249 return gen_rtx_AND (0, op0
, op1
);
3252 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3253 op1
= elim_reg_cond (XEXP (x
, 1), regno
);
3254 if (op0
== const1_rtx
|| op1
== const1_rtx
)
3256 if (op0
== const0_rtx
)
3258 if (op1
== const0_rtx
)
3260 if (op0
== XEXP (x
, 0) && op1
== XEXP (x
, 1))
3262 return gen_rtx_IOR (0, op0
, op1
);
3265 op0
= elim_reg_cond (XEXP (x
, 0), regno
);
3266 if (op0
== const0_rtx
)
3268 if (op0
== const1_rtx
)
3270 if (op0
!= XEXP (x
, 0))
3271 return not_reg_cond (op0
);
3278 #endif /* HAVE_conditional_execution */
3282 /* Try to substitute the auto-inc expression INC as the address inside
3283 MEM which occurs in INSN. Currently, the address of MEM is an expression
3284 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3285 that has a single set whose source is a PLUS of INCR_REG and something
3289 attempt_auto_inc (pbi
, inc
, insn
, mem
, incr
, incr_reg
)
3290 struct propagate_block_info
*pbi
;
3291 rtx inc
, insn
, mem
, incr
, incr_reg
;
3293 int regno
= REGNO (incr_reg
);
3294 rtx set
= single_set (incr
);
3295 rtx q
= SET_DEST (set
);
3296 rtx y
= SET_SRC (set
);
3297 int opnum
= XEXP (y
, 0) == incr_reg
? 0 : 1;
3299 /* Make sure this reg appears only once in this insn. */
3300 if (count_occurrences (PATTERN (insn
), incr_reg
, 1) != 1)
3303 if (dead_or_set_p (incr
, incr_reg
)
3304 /* Mustn't autoinc an eliminable register. */
3305 && (regno
>= FIRST_PSEUDO_REGISTER
3306 || ! TEST_HARD_REG_BIT (elim_reg_set
, regno
)))
3308 /* This is the simple case. Try to make the auto-inc. If
3309 we can't, we are done. Otherwise, we will do any
3310 needed updates below. */
3311 if (! validate_change (insn
, &XEXP (mem
, 0), inc
, 0))
3314 else if (GET_CODE (q
) == REG
3315 /* PREV_INSN used here to check the semi-open interval
3317 && ! reg_used_between_p (q
, PREV_INSN (insn
), incr
)
3318 /* We must also check for sets of q as q may be
3319 a call clobbered hard register and there may
3320 be a call between PREV_INSN (insn) and incr. */
3321 && ! reg_set_between_p (q
, PREV_INSN (insn
), incr
))
3323 /* We have *p followed sometime later by q = p+size.
3324 Both p and q must be live afterward,
3325 and q is not used between INSN and its assignment.
3326 Change it to q = p, ...*q..., q = q+size.
3327 Then fall into the usual case. */
3331 emit_move_insn (q
, incr_reg
);
3332 insns
= get_insns ();
3335 /* If we can't make the auto-inc, or can't make the
3336 replacement into Y, exit. There's no point in making
3337 the change below if we can't do the auto-inc and doing
3338 so is not correct in the pre-inc case. */
3341 validate_change (insn
, &XEXP (mem
, 0), inc
, 1);
3342 validate_change (incr
, &XEXP (y
, opnum
), q
, 1);
3343 if (! apply_change_group ())
3346 /* We now know we'll be doing this change, so emit the
3347 new insn(s) and do the updates. */
3348 emit_insns_before (insns
, insn
);
3350 if (pbi
->bb
->head
== insn
)
3351 pbi
->bb
->head
= insns
;
3353 /* INCR will become a NOTE and INSN won't contain a
3354 use of INCR_REG. If a use of INCR_REG was just placed in
3355 the insn before INSN, make that the next use.
3356 Otherwise, invalidate it. */
3357 if (GET_CODE (PREV_INSN (insn
)) == INSN
3358 && GET_CODE (PATTERN (PREV_INSN (insn
))) == SET
3359 && SET_SRC (PATTERN (PREV_INSN (insn
))) == incr_reg
)
3360 pbi
->reg_next_use
[regno
] = PREV_INSN (insn
);
3362 pbi
->reg_next_use
[regno
] = 0;
3367 /* REGNO is now used in INCR which is below INSN, but
3368 it previously wasn't live here. If we don't mark
3369 it as live, we'll put a REG_DEAD note for it
3370 on this insn, which is incorrect. */
3371 SET_REGNO_REG_SET (pbi
->reg_live
, regno
);
3373 /* If there are any calls between INSN and INCR, show
3374 that REGNO now crosses them. */
3375 for (temp
= insn
; temp
!= incr
; temp
= NEXT_INSN (temp
))
3376 if (GET_CODE (temp
) == CALL_INSN
)
3377 REG_N_CALLS_CROSSED (regno
)++;
3379 /* Invalidate alias info for Q since we just changed its value. */
3380 clear_reg_alias_info (q
);
3385 /* If we haven't returned, it means we were able to make the
3386 auto-inc, so update the status. First, record that this insn
3387 has an implicit side effect. */
3389 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, incr_reg
, REG_NOTES (insn
));
3391 /* Modify the old increment-insn to simply copy
3392 the already-incremented value of our register. */
3393 if (! validate_change (incr
, &SET_SRC (set
), incr_reg
, 0))
3396 /* If that makes it a no-op (copying the register into itself) delete
3397 it so it won't appear to be a "use" and a "set" of this
3399 if (REGNO (SET_DEST (set
)) == REGNO (incr_reg
))
3401 /* If the original source was dead, it's dead now. */
3404 while ((note
= find_reg_note (incr
, REG_DEAD
, NULL_RTX
)) != NULL_RTX
)
3406 remove_note (incr
, note
);
3407 if (XEXP (note
, 0) != incr_reg
)
3408 CLEAR_REGNO_REG_SET (pbi
->reg_live
, REGNO (XEXP (note
, 0)));
3411 PUT_CODE (incr
, NOTE
);
3412 NOTE_LINE_NUMBER (incr
) = NOTE_INSN_DELETED
;
3413 NOTE_SOURCE_FILE (incr
) = 0;
3416 if (regno
>= FIRST_PSEUDO_REGISTER
)
3418 /* Count an extra reference to the reg. When a reg is
3419 incremented, spilling it is worse, so we want to make
3420 that less likely. */
3421 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
3423 /* Count the increment as a setting of the register,
3424 even though it isn't a SET in rtl. */
3425 REG_N_SETS (regno
)++;
3429 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3433 find_auto_inc (pbi
, x
, insn
)
3434 struct propagate_block_info
*pbi
;
3438 rtx addr
= XEXP (x
, 0);
3439 HOST_WIDE_INT offset
= 0;
3440 rtx set
, y
, incr
, inc_val
;
3442 int size
= GET_MODE_SIZE (GET_MODE (x
));
3444 if (GET_CODE (insn
) == JUMP_INSN
)
3447 /* Here we detect use of an index register which might be good for
3448 postincrement, postdecrement, preincrement, or predecrement. */
3450 if (GET_CODE (addr
) == PLUS
&& GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
3451 offset
= INTVAL (XEXP (addr
, 1)), addr
= XEXP (addr
, 0);
3453 if (GET_CODE (addr
) != REG
)
3456 regno
= REGNO (addr
);
3458 /* Is the next use an increment that might make auto-increment? */
3459 incr
= pbi
->reg_next_use
[regno
];
3460 if (incr
== 0 || BLOCK_NUM (incr
) != BLOCK_NUM (insn
))
3462 set
= single_set (incr
);
3463 if (set
== 0 || GET_CODE (set
) != SET
)
3467 if (GET_CODE (y
) != PLUS
)
3470 if (REG_P (XEXP (y
, 0)) && REGNO (XEXP (y
, 0)) == REGNO (addr
))
3471 inc_val
= XEXP (y
, 1);
3472 else if (REG_P (XEXP (y
, 1)) && REGNO (XEXP (y
, 1)) == REGNO (addr
))
3473 inc_val
= XEXP (y
, 0);
3477 if (GET_CODE (inc_val
) == CONST_INT
)
3479 if (HAVE_POST_INCREMENT
3480 && (INTVAL (inc_val
) == size
&& offset
== 0))
3481 attempt_auto_inc (pbi
, gen_rtx_POST_INC (Pmode
, addr
), insn
, x
,
3483 else if (HAVE_POST_DECREMENT
3484 && (INTVAL (inc_val
) == -size
&& offset
== 0))
3485 attempt_auto_inc (pbi
, gen_rtx_POST_DEC (Pmode
, addr
), insn
, x
,
3487 else if (HAVE_PRE_INCREMENT
3488 && (INTVAL (inc_val
) == size
&& offset
== size
))
3489 attempt_auto_inc (pbi
, gen_rtx_PRE_INC (Pmode
, addr
), insn
, x
,
3491 else if (HAVE_PRE_DECREMENT
3492 && (INTVAL (inc_val
) == -size
&& offset
== -size
))
3493 attempt_auto_inc (pbi
, gen_rtx_PRE_DEC (Pmode
, addr
), insn
, x
,
3495 else if (HAVE_POST_MODIFY_DISP
&& offset
== 0)
3496 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3497 gen_rtx_PLUS (Pmode
,
3500 insn
, x
, incr
, addr
);
3502 else if (GET_CODE (inc_val
) == REG
3503 && ! reg_set_between_p (inc_val
, PREV_INSN (insn
),
3507 if (HAVE_POST_MODIFY_REG
&& offset
== 0)
3508 attempt_auto_inc (pbi
, gen_rtx_POST_MODIFY (Pmode
, addr
,
3509 gen_rtx_PLUS (Pmode
,
3512 insn
, x
, incr
, addr
);
3516 #endif /* AUTO_INC_DEC */
3519 mark_used_reg (pbi
, reg
, cond
, insn
)
3520 struct propagate_block_info
*pbi
;
3522 rtx cond ATTRIBUTE_UNUSED
;
3525 unsigned int regno_first
, regno_last
, i
;
3526 int some_was_live
, some_was_dead
, some_not_set
;
3528 regno_last
= regno_first
= REGNO (reg
);
3529 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3530 regno_last
+= HARD_REGNO_NREGS (regno_first
, GET_MODE (reg
)) - 1;
3532 /* Find out if any of this register is live after this instruction. */
3533 some_was_live
= some_was_dead
= 0;
3534 for (i
= regno_first
; i
<= regno_last
; ++i
)
3536 int needed_regno
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3537 some_was_live
|= needed_regno
;
3538 some_was_dead
|= ! needed_regno
;
3541 /* Find out if any of the register was set this insn. */
3543 for (i
= regno_first
; i
<= regno_last
; ++i
)
3544 some_not_set
|= ! REGNO_REG_SET_P (pbi
->new_set
, i
);
3546 if (pbi
->flags
& (PROP_LOG_LINKS
| PROP_AUTOINC
))
3548 /* Record where each reg is used, so when the reg is set we know
3549 the next insn that uses it. */
3550 pbi
->reg_next_use
[regno_first
] = insn
;
3553 if (pbi
->flags
& PROP_REG_INFO
)
3555 if (regno_first
< FIRST_PSEUDO_REGISTER
)
3557 /* If this is a register we are going to try to eliminate,
3558 don't mark it live here. If we are successful in
3559 eliminating it, it need not be live unless it is used for
3560 pseudos, in which case it will have been set live when it
3561 was allocated to the pseudos. If the register will not
3562 be eliminated, reload will set it live at that point.
3564 Otherwise, record that this function uses this register. */
3565 /* ??? The PPC backend tries to "eliminate" on the pic
3566 register to itself. This should be fixed. In the mean
3567 time, hack around it. */
3569 if (! (TEST_HARD_REG_BIT (elim_reg_set
, regno_first
)
3570 && (regno_first
== FRAME_POINTER_REGNUM
3571 || regno_first
== ARG_POINTER_REGNUM
)))
3572 for (i
= regno_first
; i
<= regno_last
; ++i
)
3573 regs_ever_live
[i
] = 1;
3577 /* Keep track of which basic block each reg appears in. */
3579 int blocknum
= pbi
->bb
->index
;
3580 if (REG_BASIC_BLOCK (regno_first
) == REG_BLOCK_UNKNOWN
)
3581 REG_BASIC_BLOCK (regno_first
) = blocknum
;
3582 else if (REG_BASIC_BLOCK (regno_first
) != blocknum
)
3583 REG_BASIC_BLOCK (regno_first
) = REG_BLOCK_GLOBAL
;
3585 /* Count (weighted) number of uses of each reg. */
3586 REG_FREQ (regno_first
) += REG_FREQ_FROM_BB (pbi
->bb
);
3587 REG_N_REFS (regno_first
)++;
3591 /* Record and count the insns in which a reg dies. If it is used in
3592 this insn and was dead below the insn then it dies in this insn.
3593 If it was set in this insn, we do not make a REG_DEAD note;
3594 likewise if we already made such a note. */
3595 if ((pbi
->flags
& (PROP_DEATH_NOTES
| PROP_REG_INFO
))
3599 /* Check for the case where the register dying partially
3600 overlaps the register set by this insn. */
3601 if (regno_first
!= regno_last
)
3602 for (i
= regno_first
; i
<= regno_last
; ++i
)
3603 some_was_live
|= REGNO_REG_SET_P (pbi
->new_set
, i
);
3605 /* If none of the words in X is needed, make a REG_DEAD note.
3606 Otherwise, we must make partial REG_DEAD notes. */
3607 if (! some_was_live
)
3609 if ((pbi
->flags
& PROP_DEATH_NOTES
)
3610 && ! find_regno_note (insn
, REG_DEAD
, regno_first
))
3612 = alloc_EXPR_LIST (REG_DEAD
, reg
, REG_NOTES (insn
));
3614 if (pbi
->flags
& PROP_REG_INFO
)
3615 REG_N_DEATHS (regno_first
)++;
3619 /* Don't make a REG_DEAD note for a part of a register
3620 that is set in the insn. */
3621 for (i
= regno_first
; i
<= regno_last
; ++i
)
3622 if (! REGNO_REG_SET_P (pbi
->reg_live
, i
)
3623 && ! dead_or_set_regno_p (insn
, i
))
3625 = alloc_EXPR_LIST (REG_DEAD
,
3626 gen_rtx_REG (reg_raw_mode
[i
], i
),
3631 /* Mark the register as being live. */
3632 for (i
= regno_first
; i
<= regno_last
; ++i
)
3634 #ifdef HAVE_conditional_execution
3635 int this_was_live
= REGNO_REG_SET_P (pbi
->reg_live
, i
);
3638 SET_REGNO_REG_SET (pbi
->reg_live
, i
);
3640 #ifdef HAVE_conditional_execution
3641 /* If this is a conditional use, record that fact. If it is later
3642 conditionally set, we'll know to kill the register. */
3643 if (cond
!= NULL_RTX
)
3645 splay_tree_node node
;
3646 struct reg_cond_life_info
*rcli
;
3651 node
= splay_tree_lookup (pbi
->reg_cond_dead
, i
);
3654 /* The register was unconditionally live previously.
3655 No need to do anything. */
3659 /* The register was conditionally live previously.
3660 Subtract the new life cond from the old death cond. */
3661 rcli
= (struct reg_cond_life_info
*) node
->value
;
3662 ncond
= rcli
->condition
;
3663 ncond
= and_reg_cond (ncond
, not_reg_cond (cond
), 1);
3665 /* If the register is now unconditionally live,
3666 remove the entry in the splay_tree. */
3667 if (ncond
== const0_rtx
)
3668 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3671 rcli
->condition
= ncond
;
3672 SET_REGNO_REG_SET (pbi
->reg_cond_reg
,
3673 REGNO (XEXP (cond
, 0)));
3679 /* The register was not previously live at all. Record
3680 the condition under which it is still dead. */
3681 rcli
= (struct reg_cond_life_info
*) xmalloc (sizeof (*rcli
));
3682 rcli
->condition
= not_reg_cond (cond
);
3683 rcli
->stores
= const0_rtx
;
3684 rcli
->orig_condition
= const0_rtx
;
3685 splay_tree_insert (pbi
->reg_cond_dead
, i
,
3686 (splay_tree_value
) rcli
);
3688 SET_REGNO_REG_SET (pbi
->reg_cond_reg
, REGNO (XEXP (cond
, 0)));
3691 else if (this_was_live
)
3693 /* The register may have been conditionally live previously, but
3694 is now unconditionally live. Remove it from the conditionally
3695 dead list, so that a conditional set won't cause us to think
3697 splay_tree_remove (pbi
->reg_cond_dead
, i
);
3703 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3704 This is done assuming the registers needed from X are those that
3705 have 1-bits in PBI->REG_LIVE.
3707 INSN is the containing instruction. If INSN is dead, this function
3711 mark_used_regs (pbi
, x
, cond
, insn
)
3712 struct propagate_block_info
*pbi
;
3717 int flags
= pbi
->flags
;
3722 code
= GET_CODE (x
);
3743 /* If we are clobbering a MEM, mark any registers inside the address
3745 if (GET_CODE (XEXP (x
, 0)) == MEM
)
3746 mark_used_regs (pbi
, XEXP (XEXP (x
, 0), 0), cond
, insn
);
3750 /* Don't bother watching stores to mems if this is not the
3751 final pass. We'll not be deleting dead stores this round. */
3752 if (optimize
&& (flags
& PROP_SCAN_DEAD_CODE
))
3754 /* Invalidate the data for the last MEM stored, but only if MEM is
3755 something that can be stored into. */
3756 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3757 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3758 /* Needn't clear the memory set list. */
3762 rtx temp
= pbi
->mem_set_list
;
3763 rtx prev
= NULL_RTX
;
3768 next
= XEXP (temp
, 1);
3769 if (anti_dependence (XEXP (temp
, 0), x
))
3771 /* Splice temp out of the list. */
3773 XEXP (prev
, 1) = next
;
3775 pbi
->mem_set_list
= next
;
3776 free_EXPR_LIST_node (temp
);
3777 pbi
->mem_set_list_len
--;
3785 /* If the memory reference had embedded side effects (autoincrement
3786 address modes. Then we may need to kill some entries on the
3789 for_each_rtx (&PATTERN (insn
), invalidate_mems_from_autoinc
, pbi
);
3793 if (flags
& PROP_AUTOINC
)
3794 find_auto_inc (pbi
, x
, insn
);
3799 #ifdef CLASS_CANNOT_CHANGE_MODE
3800 if (GET_CODE (SUBREG_REG (x
)) == REG
3801 && REGNO (SUBREG_REG (x
)) >= FIRST_PSEUDO_REGISTER
3802 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x
),
3803 GET_MODE (SUBREG_REG (x
))))
3804 REG_CHANGES_MODE (REGNO (SUBREG_REG (x
))) = 1;
3807 /* While we're here, optimize this case. */
3809 if (GET_CODE (x
) != REG
)
3814 /* See a register other than being set => mark it as needed. */
3815 mark_used_reg (pbi
, x
, cond
, insn
);
3820 rtx testreg
= SET_DEST (x
);
3823 /* If storing into MEM, don't show it as being used. But do
3824 show the address as being used. */
3825 if (GET_CODE (testreg
) == MEM
)
3828 if (flags
& PROP_AUTOINC
)
3829 find_auto_inc (pbi
, testreg
, insn
);
3831 mark_used_regs (pbi
, XEXP (testreg
, 0), cond
, insn
);
3832 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3836 /* Storing in STRICT_LOW_PART is like storing in a reg
3837 in that this SET might be dead, so ignore it in TESTREG.
3838 but in some other ways it is like using the reg.
3840 Storing in a SUBREG or a bit field is like storing the entire
3841 register in that if the register's value is not used
3842 then this SET is not needed. */
3843 while (GET_CODE (testreg
) == STRICT_LOW_PART
3844 || GET_CODE (testreg
) == ZERO_EXTRACT
3845 || GET_CODE (testreg
) == SIGN_EXTRACT
3846 || GET_CODE (testreg
) == SUBREG
)
3848 #ifdef CLASS_CANNOT_CHANGE_MODE
3849 if (GET_CODE (testreg
) == SUBREG
3850 && GET_CODE (SUBREG_REG (testreg
)) == REG
3851 && REGNO (SUBREG_REG (testreg
)) >= FIRST_PSEUDO_REGISTER
3852 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg
)),
3853 GET_MODE (testreg
)))
3854 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg
))) = 1;
3857 /* Modifying a single register in an alternate mode
3858 does not use any of the old value. But these other
3859 ways of storing in a register do use the old value. */
3860 if (GET_CODE (testreg
) == SUBREG
3861 && !((REG_BYTES (SUBREG_REG (testreg
))
3862 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
3863 > (REG_BYTES (testreg
)
3864 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))
3869 testreg
= XEXP (testreg
, 0);
3872 /* If this is a store into a register or group of registers,
3873 recursively scan the value being stored. */
3875 if ((GET_CODE (testreg
) == PARALLEL
3876 && GET_MODE (testreg
) == BLKmode
)
3877 || (GET_CODE (testreg
) == REG
3878 && (regno
= REGNO (testreg
),
3879 ! (regno
== FRAME_POINTER_REGNUM
3880 && (! reload_completed
|| frame_pointer_needed
)))
3881 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3882 && ! (regno
== HARD_FRAME_POINTER_REGNUM
3883 && (! reload_completed
|| frame_pointer_needed
))
3885 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3886 && ! (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
3891 mark_used_regs (pbi
, SET_DEST (x
), cond
, insn
);
3892 mark_used_regs (pbi
, SET_SRC (x
), cond
, insn
);
3899 case UNSPEC_VOLATILE
:
3903 /* Traditional and volatile asm instructions must be considered to use
3904 and clobber all hard registers, all pseudo-registers and all of
3905 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3907 Consider for instance a volatile asm that changes the fpu rounding
3908 mode. An insn should not be moved across this even if it only uses
3909 pseudo-regs because it might give an incorrectly rounded result.
3911 ?!? Unfortunately, marking all hard registers as live causes massive
3912 problems for the register allocator and marking all pseudos as live
3913 creates mountains of uninitialized variable warnings.
3915 So for now, just clear the memory set list and mark any regs
3916 we can find in ASM_OPERANDS as used. */
3917 if (code
!= ASM_OPERANDS
|| MEM_VOLATILE_P (x
))
3919 free_EXPR_LIST_list (&pbi
->mem_set_list
);
3920 pbi
->mem_set_list_len
= 0;
3923 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3924 We can not just fall through here since then we would be confused
3925 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3926 traditional asms unlike their normal usage. */
3927 if (code
== ASM_OPERANDS
)
3931 for (j
= 0; j
< ASM_OPERANDS_INPUT_LENGTH (x
); j
++)
3932 mark_used_regs (pbi
, ASM_OPERANDS_INPUT (x
, j
), cond
, insn
);
3938 if (cond
!= NULL_RTX
)
3941 mark_used_regs (pbi
, COND_EXEC_TEST (x
), NULL_RTX
, insn
);
3943 cond
= COND_EXEC_TEST (x
);
3944 x
= COND_EXEC_CODE (x
);
3948 /* We _do_not_ want to scan operands of phi nodes. Operands of
3949 a phi function are evaluated only when control reaches this
3950 block along a particular edge. Therefore, regs that appear
3951 as arguments to phi should not be added to the global live at
3959 /* Recursively scan the operands of this expression. */
3962 const char * const fmt
= GET_RTX_FORMAT (code
);
3965 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3969 /* Tail recursive case: save a function call level. */
3975 mark_used_regs (pbi
, XEXP (x
, i
), cond
, insn
);
3977 else if (fmt
[i
] == 'E')
3980 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3981 mark_used_regs (pbi
, XVECEXP (x
, i
, j
), cond
, insn
);
3990 try_pre_increment_1 (pbi
, insn
)
3991 struct propagate_block_info
*pbi
;
3994 /* Find the next use of this reg. If in same basic block,
3995 make it do pre-increment or pre-decrement if appropriate. */
3996 rtx x
= single_set (insn
);
3997 HOST_WIDE_INT amount
= ((GET_CODE (SET_SRC (x
)) == PLUS
? 1 : -1)
3998 * INTVAL (XEXP (SET_SRC (x
), 1)));
3999 int regno
= REGNO (SET_DEST (x
));
4000 rtx y
= pbi
->reg_next_use
[regno
];
4002 && SET_DEST (x
) != stack_pointer_rtx
4003 && BLOCK_NUM (y
) == BLOCK_NUM (insn
)
4004 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4005 mode would be better. */
4006 && ! dead_or_set_p (y
, SET_DEST (x
))
4007 && try_pre_increment (y
, SET_DEST (x
), amount
))
4009 /* We have found a suitable auto-increment and already changed
4010 insn Y to do it. So flush this increment instruction. */
4011 propagate_block_delete_insn (insn
);
4013 /* Count a reference to this reg for the increment insn we are
4014 deleting. When a reg is incremented, spilling it is worse,
4015 so we want to make that less likely. */
4016 if (regno
>= FIRST_PSEUDO_REGISTER
)
4018 REG_FREQ (regno
) += REG_FREQ_FROM_BB (pbi
->bb
);
4019 REG_N_SETS (regno
)++;
4022 /* Flush any remembered memories depending on the value of
4023 the incremented register. */
4024 invalidate_mems_from_set (pbi
, SET_DEST (x
));
4031 /* Try to change INSN so that it does pre-increment or pre-decrement
4032 addressing on register REG in order to add AMOUNT to REG.
4033 AMOUNT is negative for pre-decrement.
4034 Returns 1 if the change could be made.
4035 This checks all about the validity of the result of modifying INSN. */
4038 try_pre_increment (insn
, reg
, amount
)
4040 HOST_WIDE_INT amount
;
4044 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4045 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4047 /* Nonzero if we can try to make a post-increment or post-decrement.
4048 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4049 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4050 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4053 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4056 /* From the sign of increment, see which possibilities are conceivable
4057 on this target machine. */
4058 if (HAVE_PRE_INCREMENT
&& amount
> 0)
4060 if (HAVE_POST_INCREMENT
&& amount
> 0)
4063 if (HAVE_PRE_DECREMENT
&& amount
< 0)
4065 if (HAVE_POST_DECREMENT
&& amount
< 0)
4068 if (! (pre_ok
|| post_ok
))
4071 /* It is not safe to add a side effect to a jump insn
4072 because if the incremented register is spilled and must be reloaded
4073 there would be no way to store the incremented value back in memory. */
4075 if (GET_CODE (insn
) == JUMP_INSN
)
4080 use
= find_use_as_address (PATTERN (insn
), reg
, 0);
4081 if (post_ok
&& (use
== 0 || use
== (rtx
) (size_t) 1))
4083 use
= find_use_as_address (PATTERN (insn
), reg
, -amount
);
4087 if (use
== 0 || use
== (rtx
) (size_t) 1)
4090 if (GET_MODE_SIZE (GET_MODE (use
)) != (amount
> 0 ? amount
: - amount
))
4093 /* See if this combination of instruction and addressing mode exists. */
4094 if (! validate_change (insn
, &XEXP (use
, 0),
4095 gen_rtx_fmt_e (amount
> 0
4096 ? (do_post
? POST_INC
: PRE_INC
)
4097 : (do_post
? POST_DEC
: PRE_DEC
),
4101 /* Record that this insn now has an implicit side effect on X. */
4102 REG_NOTES (insn
) = alloc_EXPR_LIST (REG_INC
, reg
, REG_NOTES (insn
));
4106 #endif /* AUTO_INC_DEC */
4108 /* Find the place in the rtx X where REG is used as a memory address.
4109 Return the MEM rtx that so uses it.
4110 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4111 (plus REG (const_int PLUSCONST)).
4113 If such an address does not appear, return 0.
4114 If REG appears more than once, or is used other than in such an address,
4118 find_use_as_address (x
, reg
, plusconst
)
4121 HOST_WIDE_INT plusconst
;
4123 enum rtx_code code
= GET_CODE (x
);
4124 const char * const fmt
= GET_RTX_FORMAT (code
);
4129 if (code
== MEM
&& XEXP (x
, 0) == reg
&& plusconst
== 0)
4132 if (code
== MEM
&& GET_CODE (XEXP (x
, 0)) == PLUS
4133 && XEXP (XEXP (x
, 0), 0) == reg
4134 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
4135 && INTVAL (XEXP (XEXP (x
, 0), 1)) == plusconst
)
4138 if (code
== SIGN_EXTRACT
|| code
== ZERO_EXTRACT
)
4140 /* If REG occurs inside a MEM used in a bit-field reference,
4141 that is unacceptable. */
4142 if (find_use_as_address (XEXP (x
, 0), reg
, 0) != 0)
4143 return (rtx
) (size_t) 1;
4147 return (rtx
) (size_t) 1;
4149 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4153 tem
= find_use_as_address (XEXP (x
, i
), reg
, plusconst
);
4157 return (rtx
) (size_t) 1;
4159 else if (fmt
[i
] == 'E')
4162 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4164 tem
= find_use_as_address (XVECEXP (x
, i
, j
), reg
, plusconst
);
4168 return (rtx
) (size_t) 1;
4176 /* Write information about registers and basic blocks into FILE.
4177 This is part of making a debugging dump. */
4180 dump_regset (r
, outf
)
4187 fputs (" (nil)", outf
);
4191 EXECUTE_IF_SET_IN_REG_SET (r
, 0, i
,
4193 fprintf (outf
, " %d", i
);
4194 if (i
< FIRST_PSEUDO_REGISTER
)
4195 fprintf (outf
, " [%s]",
4200 /* Print a human-reaable representation of R on the standard error
4201 stream. This function is designed to be used from within the
4208 dump_regset (r
, stderr
);
4209 putc ('\n', stderr
);
4212 /* Recompute register set/reference counts immediately prior to register
4215 This avoids problems with set/reference counts changing to/from values
4216 which have special meanings to the register allocators.
4218 Additionally, the reference counts are the primary component used by the
4219 register allocators to prioritize pseudos for allocation to hard regs.
4220 More accurate reference counts generally lead to better register allocation.
4222 F is the first insn to be scanned.
4224 LOOP_STEP denotes how much loop_depth should be incremented per
4225 loop nesting level in order to increase the ref count more for
4226 references in a loop.
4228 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4229 possibly other information which is used by the register allocators. */
4232 recompute_reg_usage (f
, loop_step
)
4233 rtx f ATTRIBUTE_UNUSED
;
4234 int loop_step ATTRIBUTE_UNUSED
;
4236 allocate_reg_life_data ();
4237 update_life_info (NULL
, UPDATE_LIFE_LOCAL
, PROP_REG_INFO
);
4240 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4241 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4242 of the number of registers that died. */
4245 count_or_remove_death_notes (blocks
, kill
)
4251 for (i
= n_basic_blocks
- 1; i
>= 0; --i
)
4256 if (blocks
&& ! TEST_BIT (blocks
, i
))
4259 bb
= BASIC_BLOCK (i
);
4261 for (insn
= bb
->head
;; insn
= NEXT_INSN (insn
))
4265 rtx
*pprev
= ®_NOTES (insn
);
4270 switch (REG_NOTE_KIND (link
))
4273 if (GET_CODE (XEXP (link
, 0)) == REG
)
4275 rtx reg
= XEXP (link
, 0);
4278 if (REGNO (reg
) >= FIRST_PSEUDO_REGISTER
)
4281 n
= HARD_REGNO_NREGS (REGNO (reg
), GET_MODE (reg
));
4289 rtx next
= XEXP (link
, 1);
4290 free_EXPR_LIST_node (link
);
4291 *pprev
= link
= next
;
4297 pprev
= &XEXP (link
, 1);
4304 if (insn
== bb
->end
)
4311 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4312 if blocks is NULL. */
4315 clear_log_links (blocks
)
4323 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
4325 free_INSN_LIST_list (&LOG_LINKS (insn
));
4328 EXECUTE_IF_SET_IN_SBITMAP (blocks
, 0, i
,
4330 basic_block bb
= BASIC_BLOCK (i
);
4332 for (insn
= bb
->head
; insn
!= NEXT_INSN (bb
->end
);
4333 insn
= NEXT_INSN (insn
))
4335 free_INSN_LIST_list (&LOG_LINKS (insn
));
4339 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4340 correspond to the hard registers, if any, set in that map. This
4341 could be done far more efficiently by having all sorts of special-cases
4342 with moving single words, but probably isn't worth the trouble. */
4345 reg_set_to_hard_reg_set (to
, from
)
4351 EXECUTE_IF_SET_IN_BITMAP
4354 if (i
>= FIRST_PSEUDO_REGISTER
)
4356 SET_HARD_REG_BIT (*to
, i
);