1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* Nonzero if the second flow pass has completed. */
180 /* Maximum register number used in this function, plus one. */
184 /* Indexed by n, giving various register information */
186 varray_type reg_n_info;
188 /* Size of a regset for the current function,
189 in (1) bytes and (2) elements. */
194 /* Regset of regs live when calls to `setjmp'-like functions happen. */
195 /* ??? Does this exist only for the setjmp-clobbered warning message? */
197 regset regs_live_at_setjmp;
199 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
200 that have to go in the same hard reg.
201 The first two regs in the list are a pair, and the next two
202 are another pair, etc. */
205 /* Callback that determines if it's ok for a function to have no
206 noreturn attribute. */
207 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
209 /* Set of registers that may be eliminable. These are handled specially
210 in updating regs_ever_live. */
212 static HARD_REG_SET elim_reg_set;
214 /* Holds information for tracking conditional register life information. */
215 struct reg_cond_life_info
217 /* A boolean expression of conditions under which a register is dead. */
219 /* Conditions under which a register is dead at the basic block end. */
222 /* A boolean expression of conditions under which a register has been
226 /* ??? Could store mask of bytes that are dead, so that we could finally
227 track lifetimes of multi-word registers accessed via subregs. */
230 /* For use in communicating between propagate_block and its subroutines.
231 Holds all information needed to compute life and def-use information. */
233 struct propagate_block_info
235 /* The basic block we're considering. */
238 /* Bit N is set if register N is conditionally or unconditionally live. */
241 /* Bit N is set if register N is set this insn. */
244 /* Element N is the next insn that uses (hard or pseudo) register N
245 within the current basic block; or zero, if there is no such insn. */
248 /* Contains a list of all the MEMs we are tracking for dead store
252 /* If non-null, record the set of registers set unconditionally in the
256 /* If non-null, record the set of registers set conditionally in the
258 regset cond_local_set;
260 #ifdef HAVE_conditional_execution
261 /* Indexed by register number, holds a reg_cond_life_info for each
262 register that is not unconditionally live or dead. */
263 splay_tree reg_cond_dead;
265 /* Bit N is set if register N is in an expression in reg_cond_dead. */
269 /* The length of mem_set_list. */
270 int mem_set_list_len;
272 /* Non-zero if the value of CC0 is live. */
275 /* Flags controling the set of information propagate_block collects. */
279 /* Maximum length of pbi->mem_set_list before we start dropping
280 new elements on the floor. */
281 #define MAX_MEM_SET_LIST_LEN 100
283 /* Have print_rtl_and_abort give the same information that fancy_abort
285 #define print_rtl_and_abort() \
286 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
288 /* Forward declarations */
289 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
290 static void verify_wide_reg PARAMS ((int, rtx, rtx));
291 static void verify_local_live_at_start PARAMS ((regset, basic_block));
292 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
293 static void notice_stack_pointer_modification PARAMS ((rtx));
294 static void mark_reg PARAMS ((rtx, void *));
295 static void mark_regs_live_at_end PARAMS ((regset));
296 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
297 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
298 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
299 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
300 static int insn_dead_p PARAMS ((struct propagate_block_info *,
302 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
304 static void mark_set_regs PARAMS ((struct propagate_block_info *,
306 static void mark_set_1 PARAMS ((struct propagate_block_info *,
307 enum rtx_code, rtx, rtx,
309 #ifdef HAVE_conditional_execution
310 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
312 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
313 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
314 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
316 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
317 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
318 static rtx not_reg_cond PARAMS ((rtx));
319 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
322 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
323 rtx, rtx, rtx, rtx, rtx));
324 static void find_auto_inc PARAMS ((struct propagate_block_info *,
326 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
328 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
330 static void mark_used_reg PARAMS ((struct propagate_block_info *,
332 static void mark_used_regs PARAMS ((struct propagate_block_info *,
334 void dump_flow_info PARAMS ((FILE *));
335 void debug_flow_info PARAMS ((void));
336 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
340 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
342 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
344 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
346 static void delete_dead_jumptables PARAMS ((void));
350 check_function_return_warnings ()
352 if (warn_missing_noreturn
353 && !TREE_THIS_VOLATILE (cfun->decl)
354 && EXIT_BLOCK_PTR->pred == NULL
355 && (lang_missing_noreturn_ok_p
356 && !lang_missing_noreturn_ok_p (cfun->decl)))
357 warning ("function might be possible candidate for attribute `noreturn'");
359 /* If we have a path to EXIT, then we do return. */
360 if (TREE_THIS_VOLATILE (cfun->decl)
361 && EXIT_BLOCK_PTR->pred != NULL)
362 warning ("`noreturn' function does return");
364 /* If the clobber_return_insn appears in some basic block, then we
365 do reach the end without returning a value. */
366 else if (warn_return_type
367 && cfun->x_clobber_return_insn != NULL
368 && EXIT_BLOCK_PTR->pred != NULL)
370 int max_uid = get_max_uid ();
372 /* If clobber_return_insn was excised by jump1, then renumber_insns
373 can make max_uid smaller than the number still recorded in our rtx.
374 That's fine, since this is a quick way of verifying that the insn
375 is no longer in the chain. */
376 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
378 /* Recompute insn->block mapping, since the initial mapping is
379 set before we delete unreachable blocks. */
380 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
381 warning ("control reaches end of non-void function");
386 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
387 note associated with the BLOCK. */
390 first_insn_after_basic_block_note (block)
395 /* Get the first instruction in the block. */
398 if (insn == NULL_RTX)
400 if (GET_CODE (insn) == CODE_LABEL)
401 insn = NEXT_INSN (insn);
402 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
405 return NEXT_INSN (insn);
408 /* Perform data flow analysis.
409 F is the first insn of the function; FLAGS is a set of PROP_* flags
410 to be used in accumulating flow info. */
413 life_analysis (f, file, flags)
418 #ifdef ELIMINABLE_REGS
420 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
423 /* Record which registers will be eliminated. We use this in
426 CLEAR_HARD_REG_SET (elim_reg_set);
428 #ifdef ELIMINABLE_REGS
429 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
430 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
432 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
436 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
438 /* The post-reload life analysis have (on a global basis) the same
439 registers live as was computed by reload itself. elimination
440 Otherwise offsets and such may be incorrect.
442 Reload will make some registers as live even though they do not
445 We don't want to create new auto-incs after reload, since they
446 are unlikely to be useful and can cause problems with shared
448 if (reload_completed)
449 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
451 /* We want alias analysis information for local dead store elimination. */
452 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
453 init_alias_analysis ();
455 /* Always remove no-op moves. Do this before other processing so
456 that we don't have to keep re-scanning them. */
457 delete_noop_moves (f);
459 /* Some targets can emit simpler epilogues if they know that sp was
460 not ever modified during the function. After reload, of course,
461 we've already emitted the epilogue so there's no sense searching. */
462 if (! reload_completed)
463 notice_stack_pointer_modification (f);
465 /* Allocate and zero out data structures that will record the
466 data from lifetime analysis. */
467 allocate_reg_life_data ();
468 allocate_bb_life_data ();
470 /* Find the set of registers live on function exit. */
471 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
473 /* "Update" life info from zero. It'd be nice to begin the
474 relaxation with just the exit and noreturn blocks, but that set
475 is not immediately handy. */
477 if (flags & PROP_REG_INFO)
478 memset (regs_ever_live, 0, sizeof (regs_ever_live));
479 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
482 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
483 end_alias_analysis ();
486 dump_flow_info (file);
488 free_basic_block_vars (1);
490 #ifdef ENABLE_CHECKING
494 /* Search for any REG_LABEL notes which reference deleted labels. */
495 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
497 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
499 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
504 /* Removing dead insns should've made jumptables really dead. */
505 delete_dead_jumptables ();
508 /* A subroutine of verify_wide_reg, called through for_each_rtx.
509 Search for REGNO. If found, abort if it is not wider than word_mode. */
512 verify_wide_reg_1 (px, pregno)
517 unsigned int regno = *(int *) pregno;
519 if (GET_CODE (x) == REG && REGNO (x) == regno)
521 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
528 /* A subroutine of verify_local_live_at_start. Search through insns
529 between HEAD and END looking for register REGNO. */
532 verify_wide_reg (regno, head, end)
539 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
543 head = NEXT_INSN (head);
546 /* We didn't find the register at all. Something's way screwy. */
548 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
549 print_rtl_and_abort ();
552 /* A subroutine of update_life_info. Verify that there are no untoward
553 changes in live_at_start during a local update. */
556 verify_local_live_at_start (new_live_at_start, bb)
557 regset new_live_at_start;
560 if (reload_completed)
562 /* After reload, there are no pseudos, nor subregs of multi-word
563 registers. The regsets should exactly match. */
564 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
568 fprintf (rtl_dump_file,
569 "live_at_start mismatch in bb %d, aborting\n",
571 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
572 debug_bitmap_file (rtl_dump_file, new_live_at_start);
574 print_rtl_and_abort ();
581 /* Find the set of changed registers. */
582 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
584 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
586 /* No registers should die. */
587 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
590 fprintf (rtl_dump_file,
591 "Register %d died unexpectedly in block %d\n", i,
593 print_rtl_and_abort ();
596 /* Verify that the now-live register is wider than word_mode. */
597 verify_wide_reg (i, bb->head, bb->end);
602 /* Updates life information starting with the basic blocks set in BLOCKS.
603 If BLOCKS is null, consider it to be the universal set.
605 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
606 we are only expecting local modifications to basic blocks. If we find
607 extra registers live at the beginning of a block, then we either killed
608 useful data, or we have a broken split that wants data not provided.
609 If we find registers removed from live_at_start, that means we have
610 a broken peephole that is killing a register it shouldn't.
612 ??? This is not true in one situation -- when a pre-reload splitter
613 generates subregs of a multi-word pseudo, current life analysis will
614 lose the kill. So we _can_ have a pseudo go live. How irritating.
616 Including PROP_REG_INFO does not properly refresh regs_ever_live
617 unless the caller resets it to zero. */
620 update_life_info (blocks, extent, prop_flags)
622 enum update_life_extent extent;
626 regset_head tmp_head;
629 tmp = INITIALIZE_REG_SET (tmp_head);
631 /* Changes to the CFG are only allowed when
632 doing a global update for the entire CFG. */
633 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
634 && (extent == UPDATE_LIFE_LOCAL || blocks))
637 /* For a global update, we go through the relaxation process again. */
638 if (extent != UPDATE_LIFE_LOCAL)
644 calculate_global_regs_live (blocks, blocks,
645 prop_flags & (PROP_SCAN_DEAD_CODE
646 | PROP_ALLOW_CFG_CHANGES));
648 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
649 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
652 /* Removing dead code may allow the CFG to be simplified which
653 in turn may allow for further dead code detection / removal. */
654 for (i = n_basic_blocks - 1; i >= 0; --i)
656 basic_block bb = BASIC_BLOCK (i);
658 COPY_REG_SET (tmp, bb->global_live_at_end);
659 changed |= propagate_block (bb, tmp, NULL, NULL,
660 prop_flags & (PROP_SCAN_DEAD_CODE
661 | PROP_KILL_DEAD_CODE));
664 if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE))
668 /* If asked, remove notes from the blocks we'll update. */
669 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
670 count_or_remove_death_notes (blocks, 1);
675 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
677 basic_block bb = BASIC_BLOCK (i);
679 COPY_REG_SET (tmp, bb->global_live_at_end);
680 propagate_block (bb, tmp, NULL, NULL, prop_flags);
682 if (extent == UPDATE_LIFE_LOCAL)
683 verify_local_live_at_start (tmp, bb);
688 for (i = n_basic_blocks - 1; i >= 0; --i)
690 basic_block bb = BASIC_BLOCK (i);
692 COPY_REG_SET (tmp, bb->global_live_at_end);
693 propagate_block (bb, tmp, NULL, NULL, prop_flags);
695 if (extent == UPDATE_LIFE_LOCAL)
696 verify_local_live_at_start (tmp, bb);
702 if (prop_flags & PROP_REG_INFO)
704 /* The only pseudos that are live at the beginning of the function
705 are those that were not set anywhere in the function. local-alloc
706 doesn't know how to handle these correctly, so mark them as not
707 local to any one basic block. */
708 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
709 FIRST_PSEUDO_REGISTER, i,
710 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
712 /* We have a problem with any pseudoreg that lives across the setjmp.
713 ANSI says that if a user variable does not change in value between
714 the setjmp and the longjmp, then the longjmp preserves it. This
715 includes longjmp from a place where the pseudo appears dead.
716 (In principle, the value still exists if it is in scope.)
717 If the pseudo goes in a hard reg, some other value may occupy
718 that hard reg where this pseudo is dead, thus clobbering the pseudo.
719 Conclusion: such a pseudo must not go in a hard reg. */
720 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
721 FIRST_PSEUDO_REGISTER, i,
723 if (regno_reg_rtx[i] != 0)
725 REG_LIVE_LENGTH (i) = -1;
726 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
732 /* Free the variables allocated by find_basic_blocks.
734 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
737 free_basic_block_vars (keep_head_end_p)
740 if (! keep_head_end_p)
742 if (basic_block_info)
745 VARRAY_FREE (basic_block_info);
749 ENTRY_BLOCK_PTR->aux = NULL;
750 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
751 EXIT_BLOCK_PTR->aux = NULL;
752 EXIT_BLOCK_PTR->global_live_at_start = NULL;
756 /* Delete any insns that copy a register to itself. */
759 delete_noop_moves (f)
760 rtx f ATTRIBUTE_UNUSED;
766 for (i = 0; i < n_basic_blocks; i++)
768 bb = BASIC_BLOCK (i);
769 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
771 next = NEXT_INSN (insn);
772 if (INSN_P (insn) && noop_move_p (insn))
774 /* Do not call flow_delete_insn here to not confuse backward
775 pointers of LIBCALL block. */
776 PUT_CODE (insn, NOTE);
777 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
778 NOTE_SOURCE_FILE (insn) = 0;
780 purge_dead_edges (bb);
786 /* Delete any jump tables never referenced. We can't delete them at the
787 time of removing tablejump insn as they are referenced by the preceeding
788 insns computing the destination, so we delay deleting and garbagecollect
789 them once life information is computed. */
791 delete_dead_jumptables ()
794 for (insn = get_insns (); insn; insn = next)
796 next = NEXT_INSN (insn);
797 if (GET_CODE (insn) == CODE_LABEL
798 && LABEL_NUSES (insn) == 0
799 && GET_CODE (next) == JUMP_INSN
800 && (GET_CODE (PATTERN (next)) == ADDR_VEC
801 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
804 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
805 flow_delete_insn (NEXT_INSN (insn));
806 flow_delete_insn (insn);
807 next = NEXT_INSN (next);
812 /* Determine if the stack pointer is constant over the life of the function.
813 Only useful before prologues have been emitted. */
816 notice_stack_pointer_modification_1 (x, pat, data)
818 rtx pat ATTRIBUTE_UNUSED;
819 void *data ATTRIBUTE_UNUSED;
821 if (x == stack_pointer_rtx
822 /* The stack pointer is only modified indirectly as the result
823 of a push until later in flow. See the comments in rtl.texi
824 regarding Embedded Side-Effects on Addresses. */
825 || (GET_CODE (x) == MEM
826 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
827 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
828 current_function_sp_is_unchanging = 0;
832 notice_stack_pointer_modification (f)
837 /* Assume that the stack pointer is unchanging if alloca hasn't
839 current_function_sp_is_unchanging = !current_function_calls_alloca;
840 if (! current_function_sp_is_unchanging)
843 for (insn = f; insn; insn = NEXT_INSN (insn))
847 /* Check if insn modifies the stack pointer. */
848 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
850 if (! current_function_sp_is_unchanging)
856 /* Mark a register in SET. Hard registers in large modes get all
857 of their component registers set as well. */
864 regset set = (regset) xset;
865 int regno = REGNO (reg);
867 if (GET_MODE (reg) == BLKmode)
870 SET_REGNO_REG_SET (set, regno);
871 if (regno < FIRST_PSEUDO_REGISTER)
873 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
875 SET_REGNO_REG_SET (set, regno + n);
879 /* Mark those regs which are needed at the end of the function as live
880 at the end of the last basic block. */
883 mark_regs_live_at_end (set)
888 /* If exiting needs the right stack value, consider the stack pointer
889 live at the end of the function. */
890 if ((HAVE_epilogue && reload_completed)
891 || ! EXIT_IGNORE_STACK
892 || (! FRAME_POINTER_REQUIRED
893 && ! current_function_calls_alloca
894 && flag_omit_frame_pointer)
895 || current_function_sp_is_unchanging)
897 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
900 /* Mark the frame pointer if needed at the end of the function. If
901 we end up eliminating it, it will be removed from the live list
902 of each basic block by reload. */
904 if (! reload_completed || frame_pointer_needed)
906 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
907 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
908 /* If they are different, also mark the hard frame pointer as live. */
909 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
910 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
914 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
915 /* Many architectures have a GP register even without flag_pic.
916 Assume the pic register is not in use, or will be handled by
917 other means, if it is not fixed. */
918 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
919 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
920 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
923 /* Mark all global registers, and all registers used by the epilogue
924 as being live at the end of the function since they may be
925 referenced by our caller. */
926 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
927 if (global_regs[i] || EPILOGUE_USES (i))
928 SET_REGNO_REG_SET (set, i);
930 if (HAVE_epilogue && reload_completed)
932 /* Mark all call-saved registers that we actually used. */
933 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
934 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
935 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
936 SET_REGNO_REG_SET (set, i);
939 #ifdef EH_RETURN_DATA_REGNO
940 /* Mark the registers that will contain data for the handler. */
941 if (reload_completed && current_function_calls_eh_return)
944 unsigned regno = EH_RETURN_DATA_REGNO(i);
945 if (regno == INVALID_REGNUM)
947 SET_REGNO_REG_SET (set, regno);
950 #ifdef EH_RETURN_STACKADJ_RTX
951 if ((! HAVE_epilogue || ! reload_completed)
952 && current_function_calls_eh_return)
954 rtx tmp = EH_RETURN_STACKADJ_RTX;
955 if (tmp && REG_P (tmp))
959 #ifdef EH_RETURN_HANDLER_RTX
960 if ((! HAVE_epilogue || ! reload_completed)
961 && current_function_calls_eh_return)
963 rtx tmp = EH_RETURN_HANDLER_RTX;
964 if (tmp && REG_P (tmp))
969 /* Mark function return value. */
970 diddle_return_value (mark_reg, set);
973 /* Callback function for for_each_successor_phi. DATA is a regset.
974 Sets the SRC_REGNO, the regno of the phi alternative for phi node
975 INSN, in the regset. */
978 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
979 rtx insn ATTRIBUTE_UNUSED;
980 int dest_regno ATTRIBUTE_UNUSED;
984 regset live = (regset) data;
985 SET_REGNO_REG_SET (live, src_regno);
989 /* Propagate global life info around the graph of basic blocks. Begin
990 considering blocks with their corresponding bit set in BLOCKS_IN.
991 If BLOCKS_IN is null, consider it the universal set.
993 BLOCKS_OUT is set for every block that was changed. */
996 calculate_global_regs_live (blocks_in, blocks_out, flags)
997 sbitmap blocks_in, blocks_out;
1000 basic_block *queue, *qhead, *qtail, *qend;
1001 regset tmp, new_live_at_end, call_used;
1002 regset_head tmp_head, call_used_head;
1003 regset_head new_live_at_end_head;
1006 tmp = INITIALIZE_REG_SET (tmp_head);
1007 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1008 call_used = INITIALIZE_REG_SET (call_used_head);
1010 /* Inconveniently, this is only redily available in hard reg set form. */
1011 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1012 if (call_used_regs[i])
1013 SET_REGNO_REG_SET (call_used, i);
1015 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1016 because the `head == tail' style test for an empty queue doesn't
1017 work with a full queue. */
1018 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1020 qhead = qend = queue + n_basic_blocks + 2;
1022 /* Queue the blocks set in the initial mask. Do this in reverse block
1023 number order so that we are more likely for the first round to do
1024 useful work. We use AUX non-null to flag that the block is queued. */
1027 /* Clear out the garbage that might be hanging out in bb->aux. */
1028 for (i = n_basic_blocks - 1; i >= 0; --i)
1029 BASIC_BLOCK (i)->aux = NULL;
1031 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
1033 basic_block bb = BASIC_BLOCK (i);
1040 for (i = 0; i < n_basic_blocks; ++i)
1042 basic_block bb = BASIC_BLOCK (i);
1049 sbitmap_zero (blocks_out);
1051 /* We work through the queue until there are no more blocks. What
1052 is live at the end of this block is precisely the union of what
1053 is live at the beginning of all its successors. So, we set its
1054 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1055 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1056 this block by walking through the instructions in this block in
1057 reverse order and updating as we go. If that changed
1058 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1059 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1061 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1062 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1063 must either be live at the end of the block, or used within the
1064 block. In the latter case, it will certainly never disappear
1065 from GLOBAL_LIVE_AT_START. In the former case, the register
1066 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1067 for one of the successor blocks. By induction, that cannot
1069 while (qhead != qtail)
1071 int rescan, changed;
1080 /* Begin by propagating live_at_start from the successor blocks. */
1081 CLEAR_REG_SET (new_live_at_end);
1082 for (e = bb->succ; e; e = e->succ_next)
1084 basic_block sb = e->dest;
1086 /* Call-clobbered registers die across exception and call edges. */
1087 /* ??? Abnormal call edges ignored for the moment, as this gets
1088 confused by sibling call edges, which crashes reg-stack. */
1089 if (e->flags & EDGE_EH)
1091 bitmap_operation (tmp, sb->global_live_at_start,
1092 call_used, BITMAP_AND_COMPL);
1093 IOR_REG_SET (new_live_at_end, tmp);
1096 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1099 /* The all-important stack pointer must always be live. */
1100 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1102 /* Before reload, there are a few registers that must be forced
1103 live everywhere -- which might not already be the case for
1104 blocks within infinite loops. */
1105 if (! reload_completed)
1107 /* Any reference to any pseudo before reload is a potential
1108 reference of the frame pointer. */
1109 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1111 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1112 /* Pseudos with argument area equivalences may require
1113 reloading via the argument pointer. */
1114 if (fixed_regs[ARG_POINTER_REGNUM])
1115 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1118 /* Any constant, or pseudo with constant equivalences, may
1119 require reloading from memory using the pic register. */
1120 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1121 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1122 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1125 /* Regs used in phi nodes are not included in
1126 global_live_at_start, since they are live only along a
1127 particular edge. Set those regs that are live because of a
1128 phi node alternative corresponding to this particular block. */
1130 for_each_successor_phi (bb, &set_phi_alternative_reg,
1133 if (bb == ENTRY_BLOCK_PTR)
1135 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1139 /* On our first pass through this block, we'll go ahead and continue.
1140 Recognize first pass by local_set NULL. On subsequent passes, we
1141 get to skip out early if live_at_end wouldn't have changed. */
1143 if (bb->local_set == NULL)
1145 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1146 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1151 /* If any bits were removed from live_at_end, we'll have to
1152 rescan the block. This wouldn't be necessary if we had
1153 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1154 local_live is really dependent on live_at_end. */
1155 CLEAR_REG_SET (tmp);
1156 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1157 new_live_at_end, BITMAP_AND_COMPL);
1161 /* If any of the registers in the new live_at_end set are
1162 conditionally set in this basic block, we must rescan.
1163 This is because conditional lifetimes at the end of the
1164 block do not just take the live_at_end set into account,
1165 but also the liveness at the start of each successor
1166 block. We can miss changes in those sets if we only
1167 compare the new live_at_end against the previous one. */
1168 CLEAR_REG_SET (tmp);
1169 rescan = bitmap_operation (tmp, new_live_at_end,
1170 bb->cond_local_set, BITMAP_AND);
1175 /* Find the set of changed bits. Take this opportunity
1176 to notice that this set is empty and early out. */
1177 CLEAR_REG_SET (tmp);
1178 changed = bitmap_operation (tmp, bb->global_live_at_end,
1179 new_live_at_end, BITMAP_XOR);
1183 /* If any of the changed bits overlap with local_set,
1184 we'll have to rescan the block. Detect overlap by
1185 the AND with ~local_set turning off bits. */
1186 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1191 /* Let our caller know that BB changed enough to require its
1192 death notes updated. */
1194 SET_BIT (blocks_out, bb->index);
1198 /* Add to live_at_start the set of all registers in
1199 new_live_at_end that aren't in the old live_at_end. */
1201 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1203 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1205 changed = bitmap_operation (bb->global_live_at_start,
1206 bb->global_live_at_start,
1213 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1215 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1216 into live_at_start. */
1217 propagate_block (bb, new_live_at_end, bb->local_set,
1218 bb->cond_local_set, flags);
1220 /* If live_at start didn't change, no need to go farther. */
1221 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1224 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1227 /* Queue all predecessors of BB so that we may re-examine
1228 their live_at_end. */
1229 for (e = bb->pred; e; e = e->pred_next)
1231 basic_block pb = e->src;
1232 if (pb->aux == NULL)
1243 FREE_REG_SET (new_live_at_end);
1244 FREE_REG_SET (call_used);
1248 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1250 basic_block bb = BASIC_BLOCK (i);
1251 FREE_REG_SET (bb->local_set);
1252 FREE_REG_SET (bb->cond_local_set);
1257 for (i = n_basic_blocks - 1; i >= 0; --i)
1259 basic_block bb = BASIC_BLOCK (i);
1260 FREE_REG_SET (bb->local_set);
1261 FREE_REG_SET (bb->cond_local_set);
1268 /* Subroutines of life analysis. */
1270 /* Allocate the permanent data structures that represent the results
1271 of life analysis. Not static since used also for stupid life analysis. */
1274 allocate_bb_life_data ()
1278 for (i = 0; i < n_basic_blocks; i++)
1280 basic_block bb = BASIC_BLOCK (i);
1282 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1283 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1286 ENTRY_BLOCK_PTR->global_live_at_end
1287 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1288 EXIT_BLOCK_PTR->global_live_at_start
1289 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1291 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1295 allocate_reg_life_data ()
1299 max_regno = max_reg_num ();
1301 /* Recalculate the register space, in case it has grown. Old style
1302 vector oriented regsets would set regset_{size,bytes} here also. */
1303 allocate_reg_info (max_regno, FALSE, FALSE);
1305 /* Reset all the data we'll collect in propagate_block and its
1307 for (i = 0; i < max_regno; i++)
1311 REG_N_DEATHS (i) = 0;
1312 REG_N_CALLS_CROSSED (i) = 0;
1313 REG_LIVE_LENGTH (i) = 0;
1314 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1318 /* Delete dead instructions for propagate_block. */
1321 propagate_block_delete_insn (bb, insn)
1325 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1327 /* If the insn referred to a label, and that label was attached to
1328 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1329 pretty much mandatory to delete it, because the ADDR_VEC may be
1330 referencing labels that no longer exist.
1332 INSN may reference a deleted label, particularly when a jump
1333 table has been optimized into a direct jump. There's no
1334 real good way to fix up the reference to the deleted label
1335 when the label is deleted, so we just allow it here.
1337 After dead code elimination is complete, we do search for
1338 any REG_LABEL notes which reference deleted labels as a
1341 if (inote && GET_CODE (inote) == CODE_LABEL)
1343 rtx label = XEXP (inote, 0);
1346 /* The label may be forced if it has been put in the constant
1347 pool. If that is the only use we must discard the table
1348 jump following it, but not the label itself. */
1349 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1350 && (next = next_nonnote_insn (label)) != NULL
1351 && GET_CODE (next) == JUMP_INSN
1352 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1353 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1355 rtx pat = PATTERN (next);
1356 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1357 int len = XVECLEN (pat, diff_vec_p);
1360 for (i = 0; i < len; i++)
1361 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1363 flow_delete_insn (next);
1367 if (bb->end == insn)
1369 bb->end = PREV_INSN (insn);
1370 purge_dead_edges (bb);
1372 flow_delete_insn (insn);
1375 /* Delete dead libcalls for propagate_block. Return the insn
1376 before the libcall. */
1379 propagate_block_delete_libcall (bb, insn, note)
1383 rtx first = XEXP (note, 0);
1384 rtx before = PREV_INSN (first);
1386 if (insn == bb->end)
1389 flow_delete_insn_chain (first, insn);
1393 /* Update the life-status of regs for one insn. Return the previous insn. */
1396 propagate_one_insn (pbi, insn)
1397 struct propagate_block_info *pbi;
1400 rtx prev = PREV_INSN (insn);
1401 int flags = pbi->flags;
1402 int insn_is_dead = 0;
1403 int libcall_is_dead = 0;
1407 if (! INSN_P (insn))
1410 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1411 if (flags & PROP_SCAN_DEAD_CODE)
1413 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1414 libcall_is_dead = (insn_is_dead && note != 0
1415 && libcall_dead_p (pbi, note, insn));
1418 /* If an instruction consists of just dead store(s) on final pass,
1420 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1422 /* If we're trying to delete a prologue or epilogue instruction
1423 that isn't flagged as possibly being dead, something is wrong.
1424 But if we are keeping the stack pointer depressed, we might well
1425 be deleting insns that are used to compute the amount to update
1426 it by, so they are fine. */
1427 if (reload_completed
1428 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1429 && (TYPE_RETURNS_STACK_DEPRESSED
1430 (TREE_TYPE (current_function_decl))))
1431 && (((HAVE_epilogue || HAVE_prologue)
1432 && prologue_epilogue_contains (insn))
1433 || (HAVE_sibcall_epilogue
1434 && sibcall_epilogue_contains (insn)))
1435 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1438 /* Record sets. Do this even for dead instructions, since they
1439 would have killed the values if they hadn't been deleted. */
1440 mark_set_regs (pbi, PATTERN (insn), insn);
1442 /* CC0 is now known to be dead. Either this insn used it,
1443 in which case it doesn't anymore, or clobbered it,
1444 so the next insn can't use it. */
1447 if (libcall_is_dead)
1448 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
1450 propagate_block_delete_insn (pbi->bb, insn);
1455 /* See if this is an increment or decrement that can be merged into
1456 a following memory address. */
1459 register rtx x = single_set (insn);
1461 /* Does this instruction increment or decrement a register? */
1462 if ((flags & PROP_AUTOINC)
1464 && GET_CODE (SET_DEST (x)) == REG
1465 && (GET_CODE (SET_SRC (x)) == PLUS
1466 || GET_CODE (SET_SRC (x)) == MINUS)
1467 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1468 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1469 /* Ok, look for a following memory ref we can combine with.
1470 If one is found, change the memory ref to a PRE_INC
1471 or PRE_DEC, cancel this insn, and return 1.
1472 Return 0 if nothing has been done. */
1473 && try_pre_increment_1 (pbi, insn))
1476 #endif /* AUTO_INC_DEC */
1478 CLEAR_REG_SET (pbi->new_set);
1480 /* If this is not the final pass, and this insn is copying the value of
1481 a library call and it's dead, don't scan the insns that perform the
1482 library call, so that the call's arguments are not marked live. */
1483 if (libcall_is_dead)
1485 /* Record the death of the dest reg. */
1486 mark_set_regs (pbi, PATTERN (insn), insn);
1488 insn = XEXP (note, 0);
1489 return PREV_INSN (insn);
1491 else if (GET_CODE (PATTERN (insn)) == SET
1492 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1493 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1494 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1495 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1496 /* We have an insn to pop a constant amount off the stack.
1497 (Such insns use PLUS regardless of the direction of the stack,
1498 and any insn to adjust the stack by a constant is always a pop.)
1499 These insns, if not dead stores, have no effect on life. */
1503 /* Any regs live at the time of a call instruction must not go
1504 in a register clobbered by calls. Find all regs now live and
1505 record this for them. */
1507 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1508 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1509 { REG_N_CALLS_CROSSED (i)++; });
1511 /* Record sets. Do this even for dead instructions, since they
1512 would have killed the values if they hadn't been deleted. */
1513 mark_set_regs (pbi, PATTERN (insn), insn);
1515 if (GET_CODE (insn) == CALL_INSN)
1521 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1522 cond = COND_EXEC_TEST (PATTERN (insn));
1524 /* Non-constant calls clobber memory. */
1525 if (! CONST_OR_PURE_CALL_P (insn))
1527 free_EXPR_LIST_list (&pbi->mem_set_list);
1528 pbi->mem_set_list_len = 0;
1531 /* There may be extra registers to be clobbered. */
1532 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1534 note = XEXP (note, 1))
1535 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1536 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1537 cond, insn, pbi->flags);
1539 /* Calls change all call-used and global registers. */
1540 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1541 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1543 /* We do not want REG_UNUSED notes for these registers. */
1544 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1546 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1550 /* If an insn doesn't use CC0, it becomes dead since we assume
1551 that every insn clobbers it. So show it dead here;
1552 mark_used_regs will set it live if it is referenced. */
1557 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1559 /* Sometimes we may have inserted something before INSN (such as a move)
1560 when we make an auto-inc. So ensure we will scan those insns. */
1562 prev = PREV_INSN (insn);
1565 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1571 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1572 cond = COND_EXEC_TEST (PATTERN (insn));
1574 /* Calls use their arguments. */
1575 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1577 note = XEXP (note, 1))
1578 if (GET_CODE (XEXP (note, 0)) == USE)
1579 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1582 /* The stack ptr is used (honorarily) by a CALL insn. */
1583 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1585 /* Calls may also reference any of the global registers,
1586 so they are made live. */
1587 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1589 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1594 /* On final pass, update counts of how many insns in which each reg
1596 if (flags & PROP_REG_INFO)
1597 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1598 { REG_LIVE_LENGTH (i)++; });
1603 /* Initialize a propagate_block_info struct for public consumption.
1604 Note that the structure itself is opaque to this file, but that
1605 the user can use the regsets provided here. */
1607 struct propagate_block_info *
1608 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1610 regset live, local_set, cond_local_set;
1613 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1616 pbi->reg_live = live;
1617 pbi->mem_set_list = NULL_RTX;
1618 pbi->mem_set_list_len = 0;
1619 pbi->local_set = local_set;
1620 pbi->cond_local_set = cond_local_set;
1624 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1625 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1627 pbi->reg_next_use = NULL;
1629 pbi->new_set = BITMAP_XMALLOC ();
1631 #ifdef HAVE_conditional_execution
1632 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1633 free_reg_cond_life_info);
1634 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1636 /* If this block ends in a conditional branch, for each register live
1637 from one side of the branch and not the other, record the register
1638 as conditionally dead. */
1639 if (GET_CODE (bb->end) == JUMP_INSN
1640 && any_condjump_p (bb->end))
1642 regset_head diff_head;
1643 regset diff = INITIALIZE_REG_SET (diff_head);
1644 basic_block bb_true, bb_false;
1645 rtx cond_true, cond_false, set_src;
1648 /* Identify the successor blocks. */
1649 bb_true = bb->succ->dest;
1650 if (bb->succ->succ_next != NULL)
1652 bb_false = bb->succ->succ_next->dest;
1654 if (bb->succ->flags & EDGE_FALLTHRU)
1656 basic_block t = bb_false;
1660 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1665 /* This can happen with a conditional jump to the next insn. */
1666 if (JUMP_LABEL (bb->end) != bb_true->head)
1669 /* Simplest way to do nothing. */
1673 /* Extract the condition from the branch. */
1674 set_src = SET_SRC (pc_set (bb->end));
1675 cond_true = XEXP (set_src, 0);
1676 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1677 GET_MODE (cond_true), XEXP (cond_true, 0),
1678 XEXP (cond_true, 1));
1679 if (GET_CODE (XEXP (set_src, 1)) == PC)
1682 cond_false = cond_true;
1686 /* Compute which register lead different lives in the successors. */
1687 if (bitmap_operation (diff, bb_true->global_live_at_start,
1688 bb_false->global_live_at_start, BITMAP_XOR))
1690 rtx reg = XEXP (cond_true, 0);
1692 if (GET_CODE (reg) == SUBREG)
1693 reg = SUBREG_REG (reg);
1695 if (GET_CODE (reg) != REG)
1698 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1700 /* For each such register, mark it conditionally dead. */
1701 EXECUTE_IF_SET_IN_REG_SET
1704 struct reg_cond_life_info *rcli;
1707 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1709 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1713 rcli->condition = cond;
1714 rcli->stores = const0_rtx;
1715 rcli->orig_condition = cond;
1717 splay_tree_insert (pbi->reg_cond_dead, i,
1718 (splay_tree_value) rcli);
1722 FREE_REG_SET (diff);
1726 /* If this block has no successors, any stores to the frame that aren't
1727 used later in the block are dead. So make a pass over the block
1728 recording any such that are made and show them dead at the end. We do
1729 a very conservative and simple job here. */
1731 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1732 && (TYPE_RETURNS_STACK_DEPRESSED
1733 (TREE_TYPE (current_function_decl))))
1734 && (flags & PROP_SCAN_DEAD_CODE)
1735 && (bb->succ == NULL
1736 || (bb->succ->succ_next == NULL
1737 && bb->succ->dest == EXIT_BLOCK_PTR
1738 && ! current_function_calls_eh_return)))
1741 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1742 if (GET_CODE (insn) == INSN
1743 && (set = single_set (insn))
1744 && GET_CODE (SET_DEST (set)) == MEM)
1746 rtx mem = SET_DEST (set);
1747 rtx canon_mem = canon_rtx (mem);
1749 /* This optimization is performed by faking a store to the
1750 memory at the end of the block. This doesn't work for
1751 unchanging memories because multiple stores to unchanging
1752 memory is illegal and alias analysis doesn't consider it. */
1753 if (RTX_UNCHANGING_P (canon_mem))
1756 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1757 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1758 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1759 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1760 add_to_mem_set_list (pbi, canon_mem);
1767 /* Release a propagate_block_info struct. */
1770 free_propagate_block_info (pbi)
1771 struct propagate_block_info *pbi;
1773 free_EXPR_LIST_list (&pbi->mem_set_list);
1775 BITMAP_XFREE (pbi->new_set);
1777 #ifdef HAVE_conditional_execution
1778 splay_tree_delete (pbi->reg_cond_dead);
1779 BITMAP_XFREE (pbi->reg_cond_reg);
1782 if (pbi->reg_next_use)
1783 free (pbi->reg_next_use);
1788 /* Compute the registers live at the beginning of a basic block BB from
1789 those live at the end.
1791 When called, REG_LIVE contains those live at the end. On return, it
1792 contains those live at the beginning.
1794 LOCAL_SET, if non-null, will be set with all registers killed
1795 unconditionally by this basic block.
1796 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1797 killed conditionally by this basic block. If there is any unconditional
1798 set of a register, then the corresponding bit will be set in LOCAL_SET
1799 and cleared in COND_LOCAL_SET.
1800 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1801 case, the resulting set will be equal to the union of the two sets that
1802 would otherwise be computed.
1804 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1807 propagate_block (bb, live, local_set, cond_local_set, flags)
1811 regset cond_local_set;
1814 struct propagate_block_info *pbi;
1818 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
1820 if (flags & PROP_REG_INFO)
1824 /* Process the regs live at the end of the block.
1825 Mark them as not local to any one basic block. */
1826 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
1827 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
1830 /* Scan the block an insn at a time from end to beginning. */
1833 for (insn = bb->end;; insn = prev)
1835 /* If this is a call to `setjmp' et al, warn if any
1836 non-volatile datum is live. */
1837 if ((flags & PROP_REG_INFO)
1838 && GET_CODE (insn) == CALL_INSN
1839 && find_reg_note (insn, REG_SETJMP, NULL))
1840 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
1842 prev = propagate_one_insn (pbi, insn);
1843 changed |= NEXT_INSN (prev) != insn;
1845 if (insn == bb->head)
1849 free_propagate_block_info (pbi);
1854 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1855 (SET expressions whose destinations are registers dead after the insn).
1856 NEEDED is the regset that says which regs are alive after the insn.
1858 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1860 If X is the entire body of an insn, NOTES contains the reg notes
1861 pertaining to the insn. */
1864 insn_dead_p (pbi, x, call_ok, notes)
1865 struct propagate_block_info *pbi;
1868 rtx notes ATTRIBUTE_UNUSED;
1870 enum rtx_code code = GET_CODE (x);
1873 /* If flow is invoked after reload, we must take existing AUTO_INC
1874 expresions into account. */
1875 if (reload_completed)
1877 for (; notes; notes = XEXP (notes, 1))
1879 if (REG_NOTE_KIND (notes) == REG_INC)
1881 int regno = REGNO (XEXP (notes, 0));
1883 /* Don't delete insns to set global regs. */
1884 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1885 || REGNO_REG_SET_P (pbi->reg_live, regno))
1892 /* If setting something that's a reg or part of one,
1893 see if that register's altered value will be live. */
1897 rtx r = SET_DEST (x);
1900 if (GET_CODE (r) == CC0)
1901 return ! pbi->cc0_live;
1904 /* A SET that is a subroutine call cannot be dead. */
1905 if (GET_CODE (SET_SRC (x)) == CALL)
1911 /* Don't eliminate loads from volatile memory or volatile asms. */
1912 else if (volatile_refs_p (SET_SRC (x)))
1915 if (GET_CODE (r) == MEM)
1919 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
1922 canon_r = canon_rtx (r);
1924 /* Walk the set of memory locations we are currently tracking
1925 and see if one is an identical match to this memory location.
1926 If so, this memory write is dead (remember, we're walking
1927 backwards from the end of the block to the start). Since
1928 rtx_equal_p does not check the alias set or flags, we also
1929 must have the potential for them to conflict (anti_dependence). */
1930 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
1931 if (anti_dependence (r, XEXP (temp, 0)))
1933 rtx mem = XEXP (temp, 0);
1935 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
1936 && (GET_MODE_SIZE (GET_MODE (canon_r))
1937 <= GET_MODE_SIZE (GET_MODE (mem))))
1941 /* Check if memory reference matches an auto increment. Only
1942 post increment/decrement or modify are valid. */
1943 if (GET_MODE (mem) == GET_MODE (r)
1944 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
1945 || GET_CODE (XEXP (mem, 0)) == POST_INC
1946 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
1947 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
1948 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
1955 while (GET_CODE (r) == SUBREG
1956 || GET_CODE (r) == STRICT_LOW_PART
1957 || GET_CODE (r) == ZERO_EXTRACT)
1960 if (GET_CODE (r) == REG)
1962 int regno = REGNO (r);
1965 if (REGNO_REG_SET_P (pbi->reg_live, regno))
1968 /* If this is a hard register, verify that subsequent
1969 words are not needed. */
1970 if (regno < FIRST_PSEUDO_REGISTER)
1972 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
1975 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
1979 /* Don't delete insns to set global regs. */
1980 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1983 /* Make sure insns to set the stack pointer aren't deleted. */
1984 if (regno == STACK_POINTER_REGNUM)
1987 /* ??? These bits might be redundant with the force live bits
1988 in calculate_global_regs_live. We would delete from
1989 sequential sets; whether this actually affects real code
1990 for anything but the stack pointer I don't know. */
1991 /* Make sure insns to set the frame pointer aren't deleted. */
1992 if (regno == FRAME_POINTER_REGNUM
1993 && (! reload_completed || frame_pointer_needed))
1995 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1996 if (regno == HARD_FRAME_POINTER_REGNUM
1997 && (! reload_completed || frame_pointer_needed))
2001 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2002 /* Make sure insns to set arg pointer are never deleted
2003 (if the arg pointer isn't fixed, there will be a USE
2004 for it, so we can treat it normally). */
2005 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2009 /* Otherwise, the set is dead. */
2015 /* If performing several activities, insn is dead if each activity
2016 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2017 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2019 else if (code == PARALLEL)
2021 int i = XVECLEN (x, 0);
2023 for (i--; i >= 0; i--)
2024 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2025 && GET_CODE (XVECEXP (x, 0, i)) != USE
2026 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2032 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2033 is not necessarily true for hard registers. */
2034 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2035 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2036 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2039 /* We do not check other CLOBBER or USE here. An insn consisting of just
2040 a CLOBBER or just a USE should not be deleted. */
2044 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2045 return 1 if the entire library call is dead.
2046 This is true if INSN copies a register (hard or pseudo)
2047 and if the hard return reg of the call insn is dead.
2048 (The caller should have tested the destination of the SET inside
2049 INSN already for death.)
2051 If this insn doesn't just copy a register, then we don't
2052 have an ordinary libcall. In that case, cse could not have
2053 managed to substitute the source for the dest later on,
2054 so we can assume the libcall is dead.
2056 PBI is the block info giving pseudoregs live before this insn.
2057 NOTE is the REG_RETVAL note of the insn. */
2060 libcall_dead_p (pbi, note, insn)
2061 struct propagate_block_info *pbi;
2065 rtx x = single_set (insn);
2069 register rtx r = SET_SRC (x);
2071 if (GET_CODE (r) == REG)
2073 rtx call = XEXP (note, 0);
2077 /* Find the call insn. */
2078 while (call != insn && GET_CODE (call) != CALL_INSN)
2079 call = NEXT_INSN (call);
2081 /* If there is none, do nothing special,
2082 since ordinary death handling can understand these insns. */
2086 /* See if the hard reg holding the value is dead.
2087 If this is a PARALLEL, find the call within it. */
2088 call_pat = PATTERN (call);
2089 if (GET_CODE (call_pat) == PARALLEL)
2091 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2092 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2093 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2096 /* This may be a library call that is returning a value
2097 via invisible pointer. Do nothing special, since
2098 ordinary death handling can understand these insns. */
2102 call_pat = XVECEXP (call_pat, 0, i);
2105 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2111 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2112 live at function entry. Don't count global register variables, variables
2113 in registers that can be used for function arg passing, or variables in
2114 fixed hard registers. */
2117 regno_uninitialized (regno)
2120 if (n_basic_blocks == 0
2121 || (regno < FIRST_PSEUDO_REGISTER
2122 && (global_regs[regno]
2123 || fixed_regs[regno]
2124 || FUNCTION_ARG_REGNO_P (regno))))
2127 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
2130 /* 1 if register REGNO was alive at a place where `setjmp' was called
2131 and was set more than once or is an argument.
2132 Such regs may be clobbered by `longjmp'. */
2135 regno_clobbered_at_setjmp (regno)
2138 if (n_basic_blocks == 0)
2141 return ((REG_N_SETS (regno) > 1
2142 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
2143 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2146 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2147 maximal list size; look for overlaps in mode and select the largest. */
2149 add_to_mem_set_list (pbi, mem)
2150 struct propagate_block_info *pbi;
2155 /* We don't know how large a BLKmode store is, so we must not
2156 take them into consideration. */
2157 if (GET_MODE (mem) == BLKmode)
2160 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2162 rtx e = XEXP (i, 0);
2163 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2165 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2168 /* If we must store a copy of the mem, we can just modify
2169 the mode of the stored copy. */
2170 if (pbi->flags & PROP_AUTOINC)
2171 PUT_MODE (e, GET_MODE (mem));
2180 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2183 /* Store a copy of mem, otherwise the address may be
2184 scrogged by find_auto_inc. */
2185 if (pbi->flags & PROP_AUTOINC)
2186 mem = shallow_copy_rtx (mem);
2188 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2189 pbi->mem_set_list_len++;
2193 /* INSN references memory, possibly using autoincrement addressing modes.
2194 Find any entries on the mem_set_list that need to be invalidated due
2195 to an address change. */
2198 invalidate_mems_from_autoinc (pbi, insn)
2199 struct propagate_block_info *pbi;
2202 rtx note = REG_NOTES (insn);
2203 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2204 if (REG_NOTE_KIND (note) == REG_INC)
2205 invalidate_mems_from_set (pbi, XEXP (note, 0));
2208 /* EXP is a REG. Remove any dependant entries from pbi->mem_set_list. */
2211 invalidate_mems_from_set (pbi, exp)
2212 struct propagate_block_info *pbi;
2215 rtx temp = pbi->mem_set_list;
2216 rtx prev = NULL_RTX;
2221 next = XEXP (temp, 1);
2222 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2224 /* Splice this entry out of the list. */
2226 XEXP (prev, 1) = next;
2228 pbi->mem_set_list = next;
2229 free_EXPR_LIST_node (temp);
2230 pbi->mem_set_list_len--;
2238 /* Process the registers that are set within X. Their bits are set to
2239 1 in the regset DEAD, because they are dead prior to this insn.
2241 If INSN is nonzero, it is the insn being processed.
2243 FLAGS is the set of operations to perform. */
2246 mark_set_regs (pbi, x, insn)
2247 struct propagate_block_info *pbi;
2250 rtx cond = NULL_RTX;
2255 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2257 if (REG_NOTE_KIND (link) == REG_INC)
2258 mark_set_1 (pbi, SET, XEXP (link, 0),
2259 (GET_CODE (x) == COND_EXEC
2260 ? COND_EXEC_TEST (x) : NULL_RTX),
2264 switch (code = GET_CODE (x))
2268 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2272 cond = COND_EXEC_TEST (x);
2273 x = COND_EXEC_CODE (x);
2279 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2281 rtx sub = XVECEXP (x, 0, i);
2282 switch (code = GET_CODE (sub))
2285 if (cond != NULL_RTX)
2288 cond = COND_EXEC_TEST (sub);
2289 sub = COND_EXEC_CODE (sub);
2290 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2296 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2311 /* Process a single set, which appears in INSN. REG (which may not
2312 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2313 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2314 If the set is conditional (because it appear in a COND_EXEC), COND
2315 will be the condition. */
2318 mark_set_1 (pbi, code, reg, cond, insn, flags)
2319 struct propagate_block_info *pbi;
2321 rtx reg, cond, insn;
2324 int regno_first = -1, regno_last = -1;
2325 unsigned long not_dead = 0;
2328 /* Modifying just one hardware register of a multi-reg value or just a
2329 byte field of a register does not mean the value from before this insn
2330 is now dead. Of course, if it was dead after it's unused now. */
2332 switch (GET_CODE (reg))
2335 /* Some targets place small structures in registers for return values of
2336 functions. We have to detect this case specially here to get correct
2337 flow information. */
2338 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2339 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2340 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2346 case STRICT_LOW_PART:
2347 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2349 reg = XEXP (reg, 0);
2350 while (GET_CODE (reg) == SUBREG
2351 || GET_CODE (reg) == ZERO_EXTRACT
2352 || GET_CODE (reg) == SIGN_EXTRACT
2353 || GET_CODE (reg) == STRICT_LOW_PART);
2354 if (GET_CODE (reg) == MEM)
2356 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2360 regno_last = regno_first = REGNO (reg);
2361 if (regno_first < FIRST_PSEUDO_REGISTER)
2362 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2366 if (GET_CODE (SUBREG_REG (reg)) == REG)
2368 enum machine_mode outer_mode = GET_MODE (reg);
2369 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2371 /* Identify the range of registers affected. This is moderately
2372 tricky for hard registers. See alter_subreg. */
2374 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2375 if (regno_first < FIRST_PSEUDO_REGISTER)
2377 regno_first += subreg_regno_offset (regno_first, inner_mode,
2380 regno_last = (regno_first
2381 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2383 /* Since we've just adjusted the register number ranges, make
2384 sure REG matches. Otherwise some_was_live will be clear
2385 when it shouldn't have been, and we'll create incorrect
2386 REG_UNUSED notes. */
2387 reg = gen_rtx_REG (outer_mode, regno_first);
2391 /* If the number of words in the subreg is less than the number
2392 of words in the full register, we have a well-defined partial
2393 set. Otherwise the high bits are undefined.
2395 This is only really applicable to pseudos, since we just took
2396 care of multi-word hard registers. */
2397 if (((GET_MODE_SIZE (outer_mode)
2398 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2399 < ((GET_MODE_SIZE (inner_mode)
2400 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2401 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2404 reg = SUBREG_REG (reg);
2408 reg = SUBREG_REG (reg);
2415 /* If this set is a MEM, then it kills any aliased writes.
2416 If this set is a REG, then it kills any MEMs which use the reg. */
2417 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2419 if (GET_CODE (reg) == REG)
2420 invalidate_mems_from_set (pbi, reg);
2422 /* If the memory reference had embedded side effects (autoincrement
2423 address modes. Then we may need to kill some entries on the
2425 if (insn && GET_CODE (reg) == MEM)
2426 invalidate_mems_from_autoinc (pbi, insn);
2428 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2429 /* ??? With more effort we could track conditional memory life. */
2431 /* There are no REG_INC notes for SP, so we can't assume we'll see
2432 everything that invalidates it. To be safe, don't eliminate any
2433 stores though SP; none of them should be redundant anyway. */
2434 && ! reg_mentioned_p (stack_pointer_rtx, reg))
2435 add_to_mem_set_list (pbi, canon_rtx (reg));
2438 if (GET_CODE (reg) == REG
2439 && ! (regno_first == FRAME_POINTER_REGNUM
2440 && (! reload_completed || frame_pointer_needed))
2441 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2442 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2443 && (! reload_completed || frame_pointer_needed))
2445 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2446 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2450 int some_was_live = 0, some_was_dead = 0;
2452 for (i = regno_first; i <= regno_last; ++i)
2454 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2457 /* Order of the set operation matters here since both
2458 sets may be the same. */
2459 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2460 if (cond != NULL_RTX
2461 && ! REGNO_REG_SET_P (pbi->local_set, i))
2462 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2464 SET_REGNO_REG_SET (pbi->local_set, i);
2466 if (code != CLOBBER)
2467 SET_REGNO_REG_SET (pbi->new_set, i);
2469 some_was_live |= needed_regno;
2470 some_was_dead |= ! needed_regno;
2473 #ifdef HAVE_conditional_execution
2474 /* Consider conditional death in deciding that the register needs
2476 if (some_was_live && ! not_dead
2477 /* The stack pointer is never dead. Well, not strictly true,
2478 but it's very difficult to tell from here. Hopefully
2479 combine_stack_adjustments will fix up the most egregious
2481 && regno_first != STACK_POINTER_REGNUM)
2483 for (i = regno_first; i <= regno_last; ++i)
2484 if (! mark_regno_cond_dead (pbi, i, cond))
2485 not_dead |= ((unsigned long) 1) << (i - regno_first);
2489 /* Additional data to record if this is the final pass. */
2490 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2491 | PROP_DEATH_NOTES | PROP_AUTOINC))
2494 register int blocknum = pbi->bb->index;
2497 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2499 y = pbi->reg_next_use[regno_first];
2501 /* The next use is no longer next, since a store intervenes. */
2502 for (i = regno_first; i <= regno_last; ++i)
2503 pbi->reg_next_use[i] = 0;
2506 if (flags & PROP_REG_INFO)
2508 for (i = regno_first; i <= regno_last; ++i)
2510 /* Count (weighted) references, stores, etc. This counts a
2511 register twice if it is modified, but that is correct. */
2512 REG_N_SETS (i) += 1;
2513 REG_N_REFS (i) += 1;
2514 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2516 /* The insns where a reg is live are normally counted
2517 elsewhere, but we want the count to include the insn
2518 where the reg is set, and the normal counting mechanism
2519 would not count it. */
2520 REG_LIVE_LENGTH (i) += 1;
2523 /* If this is a hard reg, record this function uses the reg. */
2524 if (regno_first < FIRST_PSEUDO_REGISTER)
2526 for (i = regno_first; i <= regno_last; i++)
2527 regs_ever_live[i] = 1;
2531 /* Keep track of which basic blocks each reg appears in. */
2532 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2533 REG_BASIC_BLOCK (regno_first) = blocknum;
2534 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2535 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2539 if (! some_was_dead)
2541 if (flags & PROP_LOG_LINKS)
2543 /* Make a logical link from the next following insn
2544 that uses this register, back to this insn.
2545 The following insns have already been processed.
2547 We don't build a LOG_LINK for hard registers containing
2548 in ASM_OPERANDs. If these registers get replaced,
2549 we might wind up changing the semantics of the insn,
2550 even if reload can make what appear to be valid
2551 assignments later. */
2552 if (y && (BLOCK_NUM (y) == blocknum)
2553 && (regno_first >= FIRST_PSEUDO_REGISTER
2554 || asm_noperands (PATTERN (y)) < 0))
2555 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2560 else if (! some_was_live)
2562 if (flags & PROP_REG_INFO)
2563 REG_N_DEATHS (regno_first) += 1;
2565 if (flags & PROP_DEATH_NOTES)
2567 /* Note that dead stores have already been deleted
2568 when possible. If we get here, we have found a
2569 dead store that cannot be eliminated (because the
2570 same insn does something useful). Indicate this
2571 by marking the reg being set as dying here. */
2573 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2578 if (flags & PROP_DEATH_NOTES)
2580 /* This is a case where we have a multi-word hard register
2581 and some, but not all, of the words of the register are
2582 needed in subsequent insns. Write REG_UNUSED notes
2583 for those parts that were not needed. This case should
2586 for (i = regno_first; i <= regno_last; ++i)
2587 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2589 = alloc_EXPR_LIST (REG_UNUSED,
2590 gen_rtx_REG (reg_raw_mode[i], i),
2596 /* Mark the register as being dead. */
2598 /* The stack pointer is never dead. Well, not strictly true,
2599 but it's very difficult to tell from here. Hopefully
2600 combine_stack_adjustments will fix up the most egregious
2602 && regno_first != STACK_POINTER_REGNUM)
2604 for (i = regno_first; i <= regno_last; ++i)
2605 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2606 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2609 else if (GET_CODE (reg) == REG)
2611 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2612 pbi->reg_next_use[regno_first] = 0;
2615 /* If this is the last pass and this is a SCRATCH, show it will be dying
2616 here and count it. */
2617 else if (GET_CODE (reg) == SCRATCH)
2619 if (flags & PROP_DEATH_NOTES)
2621 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2625 #ifdef HAVE_conditional_execution
2626 /* Mark REGNO conditionally dead.
2627 Return true if the register is now unconditionally dead. */
2630 mark_regno_cond_dead (pbi, regno, cond)
2631 struct propagate_block_info *pbi;
2635 /* If this is a store to a predicate register, the value of the
2636 predicate is changing, we don't know that the predicate as seen
2637 before is the same as that seen after. Flush all dependent
2638 conditions from reg_cond_dead. This will make all such
2639 conditionally live registers unconditionally live. */
2640 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2641 flush_reg_cond_reg (pbi, regno);
2643 /* If this is an unconditional store, remove any conditional
2644 life that may have existed. */
2645 if (cond == NULL_RTX)
2646 splay_tree_remove (pbi->reg_cond_dead, regno);
2649 splay_tree_node node;
2650 struct reg_cond_life_info *rcli;
2653 /* Otherwise this is a conditional set. Record that fact.
2654 It may have been conditionally used, or there may be a
2655 subsequent set with a complimentary condition. */
2657 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2660 /* The register was unconditionally live previously.
2661 Record the current condition as the condition under
2662 which it is dead. */
2663 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2664 rcli->condition = cond;
2665 rcli->stores = cond;
2666 rcli->orig_condition = const0_rtx;
2667 splay_tree_insert (pbi->reg_cond_dead, regno,
2668 (splay_tree_value) rcli);
2670 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2672 /* Not unconditionaly dead. */
2677 /* The register was conditionally live previously.
2678 Add the new condition to the old. */
2679 rcli = (struct reg_cond_life_info *) node->value;
2680 ncond = rcli->condition;
2681 ncond = ior_reg_cond (ncond, cond, 1);
2682 if (rcli->stores == const0_rtx)
2683 rcli->stores = cond;
2684 else if (rcli->stores != const1_rtx)
2685 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2687 /* If the register is now unconditionally dead, remove the entry
2688 in the splay_tree. A register is unconditionally dead if the
2689 dead condition ncond is true. A register is also unconditionally
2690 dead if the sum of all conditional stores is an unconditional
2691 store (stores is true), and the dead condition is identically the
2692 same as the original dead condition initialized at the end of
2693 the block. This is a pointer compare, not an rtx_equal_p
2695 if (ncond == const1_rtx
2696 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2697 splay_tree_remove (pbi->reg_cond_dead, regno);
2700 rcli->condition = ncond;
2702 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2704 /* Not unconditionaly dead. */
2713 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2716 free_reg_cond_life_info (value)
2717 splay_tree_value value;
2719 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2723 /* Helper function for flush_reg_cond_reg. */
2726 flush_reg_cond_reg_1 (node, data)
2727 splay_tree_node node;
2730 struct reg_cond_life_info *rcli;
2731 int *xdata = (int *) data;
2732 unsigned int regno = xdata[0];
2734 /* Don't need to search if last flushed value was farther on in
2735 the in-order traversal. */
2736 if (xdata[1] >= (int) node->key)
2739 /* Splice out portions of the expression that refer to regno. */
2740 rcli = (struct reg_cond_life_info *) node->value;
2741 rcli->condition = elim_reg_cond (rcli->condition, regno);
2742 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2743 rcli->stores = elim_reg_cond (rcli->stores, regno);
2745 /* If the entire condition is now false, signal the node to be removed. */
2746 if (rcli->condition == const0_rtx)
2748 xdata[1] = node->key;
2751 else if (rcli->condition == const1_rtx)
2757 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2760 flush_reg_cond_reg (pbi, regno)
2761 struct propagate_block_info *pbi;
2768 while (splay_tree_foreach (pbi->reg_cond_dead,
2769 flush_reg_cond_reg_1, pair) == -1)
2770 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2772 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2775 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2776 For ior/and, the ADD flag determines whether we want to add the new
2777 condition X to the old one unconditionally. If it is zero, we will
2778 only return a new expression if X allows us to simplify part of
2779 OLD, otherwise we return OLD unchanged to the caller.
2780 If ADD is nonzero, we will return a new condition in all cases. The
2781 toplevel caller of one of these functions should always pass 1 for
2785 ior_reg_cond (old, x, add)
2791 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2793 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2794 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2795 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2797 if (GET_CODE (x) == GET_CODE (old)
2798 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2802 return gen_rtx_IOR (0, old, x);
2805 switch (GET_CODE (old))
2808 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2809 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2810 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2812 if (op0 == const0_rtx)
2814 if (op1 == const0_rtx)
2816 if (op0 == const1_rtx || op1 == const1_rtx)
2818 if (op0 == XEXP (old, 0))
2819 op0 = gen_rtx_IOR (0, op0, x);
2821 op1 = gen_rtx_IOR (0, op1, x);
2822 return gen_rtx_IOR (0, op0, op1);
2826 return gen_rtx_IOR (0, old, x);
2829 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2830 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2831 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2833 if (op0 == const1_rtx)
2835 if (op1 == const1_rtx)
2837 if (op0 == const0_rtx || op1 == const0_rtx)
2839 if (op0 == XEXP (old, 0))
2840 op0 = gen_rtx_IOR (0, op0, x);
2842 op1 = gen_rtx_IOR (0, op1, x);
2843 return gen_rtx_AND (0, op0, op1);
2847 return gen_rtx_IOR (0, old, x);
2850 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2851 if (op0 != XEXP (old, 0))
2852 return not_reg_cond (op0);
2855 return gen_rtx_IOR (0, old, x);
2866 enum rtx_code x_code;
2868 if (x == const0_rtx)
2870 else if (x == const1_rtx)
2872 x_code = GET_CODE (x);
2875 if (GET_RTX_CLASS (x_code) == '<'
2876 && GET_CODE (XEXP (x, 0)) == REG)
2878 if (XEXP (x, 1) != const0_rtx)
2881 return gen_rtx_fmt_ee (reverse_condition (x_code),
2882 VOIDmode, XEXP (x, 0), const0_rtx);
2884 return gen_rtx_NOT (0, x);
2888 and_reg_cond (old, x, add)
2894 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2896 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2897 && GET_CODE (x) == reverse_condition (GET_CODE (old))
2898 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2900 if (GET_CODE (x) == GET_CODE (old)
2901 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2905 return gen_rtx_AND (0, old, x);
2908 switch (GET_CODE (old))
2911 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2912 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2913 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2915 if (op0 == const0_rtx)
2917 if (op1 == const0_rtx)
2919 if (op0 == const1_rtx || op1 == const1_rtx)
2921 if (op0 == XEXP (old, 0))
2922 op0 = gen_rtx_AND (0, op0, x);
2924 op1 = gen_rtx_AND (0, op1, x);
2925 return gen_rtx_IOR (0, op0, op1);
2929 return gen_rtx_AND (0, old, x);
2932 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2933 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2934 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2936 if (op0 == const1_rtx)
2938 if (op1 == const1_rtx)
2940 if (op0 == const0_rtx || op1 == const0_rtx)
2942 if (op0 == XEXP (old, 0))
2943 op0 = gen_rtx_AND (0, op0, x);
2945 op1 = gen_rtx_AND (0, op1, x);
2946 return gen_rtx_AND (0, op0, op1);
2951 /* If X is identical to one of the existing terms of the AND,
2952 then just return what we already have. */
2953 /* ??? There really should be some sort of recursive check here in
2954 case there are nested ANDs. */
2955 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
2956 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
2957 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
2958 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
2961 return gen_rtx_AND (0, old, x);
2964 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2965 if (op0 != XEXP (old, 0))
2966 return not_reg_cond (op0);
2969 return gen_rtx_AND (0, old, x);
2976 /* Given a condition X, remove references to reg REGNO and return the
2977 new condition. The removal will be done so that all conditions
2978 involving REGNO are considered to evaluate to false. This function
2979 is used when the value of REGNO changes. */
2982 elim_reg_cond (x, regno)
2988 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
2990 if (REGNO (XEXP (x, 0)) == regno)
2995 switch (GET_CODE (x))
2998 op0 = elim_reg_cond (XEXP (x, 0), regno);
2999 op1 = elim_reg_cond (XEXP (x, 1), regno);
3000 if (op0 == const0_rtx || op1 == const0_rtx)
3002 if (op0 == const1_rtx)
3004 if (op1 == const1_rtx)
3006 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3008 return gen_rtx_AND (0, op0, op1);
3011 op0 = elim_reg_cond (XEXP (x, 0), regno);
3012 op1 = elim_reg_cond (XEXP (x, 1), regno);
3013 if (op0 == const1_rtx || op1 == const1_rtx)
3015 if (op0 == const0_rtx)
3017 if (op1 == const0_rtx)
3019 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3021 return gen_rtx_IOR (0, op0, op1);
3024 op0 = elim_reg_cond (XEXP (x, 0), regno);
3025 if (op0 == const0_rtx)
3027 if (op0 == const1_rtx)
3029 if (op0 != XEXP (x, 0))
3030 return not_reg_cond (op0);
3037 #endif /* HAVE_conditional_execution */
3041 /* Try to substitute the auto-inc expression INC as the address inside
3042 MEM which occurs in INSN. Currently, the address of MEM is an expression
3043 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3044 that has a single set whose source is a PLUS of INCR_REG and something
3048 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3049 struct propagate_block_info *pbi;
3050 rtx inc, insn, mem, incr, incr_reg;
3052 int regno = REGNO (incr_reg);
3053 rtx set = single_set (incr);
3054 rtx q = SET_DEST (set);
3055 rtx y = SET_SRC (set);
3056 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3058 /* Make sure this reg appears only once in this insn. */
3059 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3062 if (dead_or_set_p (incr, incr_reg)
3063 /* Mustn't autoinc an eliminable register. */
3064 && (regno >= FIRST_PSEUDO_REGISTER
3065 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3067 /* This is the simple case. Try to make the auto-inc. If
3068 we can't, we are done. Otherwise, we will do any
3069 needed updates below. */
3070 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3073 else if (GET_CODE (q) == REG
3074 /* PREV_INSN used here to check the semi-open interval
3076 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3077 /* We must also check for sets of q as q may be
3078 a call clobbered hard register and there may
3079 be a call between PREV_INSN (insn) and incr. */
3080 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3082 /* We have *p followed sometime later by q = p+size.
3083 Both p and q must be live afterward,
3084 and q is not used between INSN and its assignment.
3085 Change it to q = p, ...*q..., q = q+size.
3086 Then fall into the usual case. */
3090 emit_move_insn (q, incr_reg);
3091 insns = get_insns ();
3094 /* If we can't make the auto-inc, or can't make the
3095 replacement into Y, exit. There's no point in making
3096 the change below if we can't do the auto-inc and doing
3097 so is not correct in the pre-inc case. */
3100 validate_change (insn, &XEXP (mem, 0), inc, 1);
3101 validate_change (incr, &XEXP (y, opnum), q, 1);
3102 if (! apply_change_group ())
3105 /* We now know we'll be doing this change, so emit the
3106 new insn(s) and do the updates. */
3107 emit_insns_before (insns, insn);
3109 if (pbi->bb->head == insn)
3110 pbi->bb->head = insns;
3112 /* INCR will become a NOTE and INSN won't contain a
3113 use of INCR_REG. If a use of INCR_REG was just placed in
3114 the insn before INSN, make that the next use.
3115 Otherwise, invalidate it. */
3116 if (GET_CODE (PREV_INSN (insn)) == INSN
3117 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3118 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3119 pbi->reg_next_use[regno] = PREV_INSN (insn);
3121 pbi->reg_next_use[regno] = 0;
3126 /* REGNO is now used in INCR which is below INSN, but
3127 it previously wasn't live here. If we don't mark
3128 it as live, we'll put a REG_DEAD note for it
3129 on this insn, which is incorrect. */
3130 SET_REGNO_REG_SET (pbi->reg_live, regno);
3132 /* If there are any calls between INSN and INCR, show
3133 that REGNO now crosses them. */
3134 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3135 if (GET_CODE (temp) == CALL_INSN)
3136 REG_N_CALLS_CROSSED (regno)++;
3138 /* Invalidate alias info for Q since we just changed its value. */
3139 clear_reg_alias_info (q);
3144 /* If we haven't returned, it means we were able to make the
3145 auto-inc, so update the status. First, record that this insn
3146 has an implicit side effect. */
3148 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3150 /* Modify the old increment-insn to simply copy
3151 the already-incremented value of our register. */
3152 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3155 /* If that makes it a no-op (copying the register into itself) delete
3156 it so it won't appear to be a "use" and a "set" of this
3158 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3160 /* If the original source was dead, it's dead now. */
3163 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3165 remove_note (incr, note);
3166 if (XEXP (note, 0) != incr_reg)
3167 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3170 PUT_CODE (incr, NOTE);
3171 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3172 NOTE_SOURCE_FILE (incr) = 0;
3175 if (regno >= FIRST_PSEUDO_REGISTER)
3177 /* Count an extra reference to the reg. When a reg is
3178 incremented, spilling it is worse, so we want to make
3179 that less likely. */
3180 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3182 /* Count the increment as a setting of the register,
3183 even though it isn't a SET in rtl. */
3184 REG_N_SETS (regno)++;
3188 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3192 find_auto_inc (pbi, x, insn)
3193 struct propagate_block_info *pbi;
3197 rtx addr = XEXP (x, 0);
3198 HOST_WIDE_INT offset = 0;
3199 rtx set, y, incr, inc_val;
3201 int size = GET_MODE_SIZE (GET_MODE (x));
3203 if (GET_CODE (insn) == JUMP_INSN)
3206 /* Here we detect use of an index register which might be good for
3207 postincrement, postdecrement, preincrement, or predecrement. */
3209 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3210 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3212 if (GET_CODE (addr) != REG)
3215 regno = REGNO (addr);
3217 /* Is the next use an increment that might make auto-increment? */
3218 incr = pbi->reg_next_use[regno];
3219 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3221 set = single_set (incr);
3222 if (set == 0 || GET_CODE (set) != SET)
3226 if (GET_CODE (y) != PLUS)
3229 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3230 inc_val = XEXP (y, 1);
3231 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3232 inc_val = XEXP (y, 0);
3236 if (GET_CODE (inc_val) == CONST_INT)
3238 if (HAVE_POST_INCREMENT
3239 && (INTVAL (inc_val) == size && offset == 0))
3240 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3242 else if (HAVE_POST_DECREMENT
3243 && (INTVAL (inc_val) == -size && offset == 0))
3244 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3246 else if (HAVE_PRE_INCREMENT
3247 && (INTVAL (inc_val) == size && offset == size))
3248 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3250 else if (HAVE_PRE_DECREMENT
3251 && (INTVAL (inc_val) == -size && offset == -size))
3252 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3254 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3255 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3256 gen_rtx_PLUS (Pmode,
3259 insn, x, incr, addr);
3261 else if (GET_CODE (inc_val) == REG
3262 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3266 if (HAVE_POST_MODIFY_REG && offset == 0)
3267 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3268 gen_rtx_PLUS (Pmode,
3271 insn, x, incr, addr);
3275 #endif /* AUTO_INC_DEC */
3278 mark_used_reg (pbi, reg, cond, insn)
3279 struct propagate_block_info *pbi;
3281 rtx cond ATTRIBUTE_UNUSED;
3284 unsigned int regno_first, regno_last, i;
3285 int some_was_live, some_was_dead, some_not_set;
3287 regno_last = regno_first = REGNO (reg);
3288 if (regno_first < FIRST_PSEUDO_REGISTER)
3289 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3291 /* Find out if any of this register is live after this instruction. */
3292 some_was_live = some_was_dead = 0;
3293 for (i = regno_first; i <= regno_last; ++i)
3295 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3296 some_was_live |= needed_regno;
3297 some_was_dead |= ! needed_regno;
3300 /* Find out if any of the register was set this insn. */
3302 for (i = regno_first; i <= regno_last; ++i)
3303 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3305 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3307 /* Record where each reg is used, so when the reg is set we know
3308 the next insn that uses it. */
3309 pbi->reg_next_use[regno_first] = insn;
3312 if (pbi->flags & PROP_REG_INFO)
3314 if (regno_first < FIRST_PSEUDO_REGISTER)
3316 /* If this is a register we are going to try to eliminate,
3317 don't mark it live here. If we are successful in
3318 eliminating it, it need not be live unless it is used for
3319 pseudos, in which case it will have been set live when it
3320 was allocated to the pseudos. If the register will not
3321 be eliminated, reload will set it live at that point.
3323 Otherwise, record that this function uses this register. */
3324 /* ??? The PPC backend tries to "eliminate" on the pic
3325 register to itself. This should be fixed. In the mean
3326 time, hack around it. */
3328 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3329 && (regno_first == FRAME_POINTER_REGNUM
3330 || regno_first == ARG_POINTER_REGNUM)))
3331 for (i = regno_first; i <= regno_last; ++i)
3332 regs_ever_live[i] = 1;
3336 /* Keep track of which basic block each reg appears in. */
3338 register int blocknum = pbi->bb->index;
3339 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3340 REG_BASIC_BLOCK (regno_first) = blocknum;
3341 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3342 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3344 /* Count (weighted) number of uses of each reg. */
3345 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3346 REG_N_REFS (regno_first)++;
3350 /* Record and count the insns in which a reg dies. If it is used in
3351 this insn and was dead below the insn then it dies in this insn.
3352 If it was set in this insn, we do not make a REG_DEAD note;
3353 likewise if we already made such a note. */
3354 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3358 /* Check for the case where the register dying partially
3359 overlaps the register set by this insn. */
3360 if (regno_first != regno_last)
3361 for (i = regno_first; i <= regno_last; ++i)
3362 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3364 /* If none of the words in X is needed, make a REG_DEAD note.
3365 Otherwise, we must make partial REG_DEAD notes. */
3366 if (! some_was_live)
3368 if ((pbi->flags & PROP_DEATH_NOTES)
3369 && ! find_regno_note (insn, REG_DEAD, regno_first))
3371 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3373 if (pbi->flags & PROP_REG_INFO)
3374 REG_N_DEATHS (regno_first)++;
3378 /* Don't make a REG_DEAD note for a part of a register
3379 that is set in the insn. */
3380 for (i = regno_first; i <= regno_last; ++i)
3381 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3382 && ! dead_or_set_regno_p (insn, i))
3384 = alloc_EXPR_LIST (REG_DEAD,
3385 gen_rtx_REG (reg_raw_mode[i], i),
3390 /* Mark the register as being live. */
3391 for (i = regno_first; i <= regno_last; ++i)
3393 SET_REGNO_REG_SET (pbi->reg_live, i);
3395 #ifdef HAVE_conditional_execution
3396 /* If this is a conditional use, record that fact. If it is later
3397 conditionally set, we'll know to kill the register. */
3398 if (cond != NULL_RTX)
3400 splay_tree_node node;
3401 struct reg_cond_life_info *rcli;
3406 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3409 /* The register was unconditionally live previously.
3410 No need to do anything. */
3414 /* The register was conditionally live previously.
3415 Subtract the new life cond from the old death cond. */
3416 rcli = (struct reg_cond_life_info *) node->value;
3417 ncond = rcli->condition;
3418 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3420 /* If the register is now unconditionally live,
3421 remove the entry in the splay_tree. */
3422 if (ncond == const0_rtx)
3423 splay_tree_remove (pbi->reg_cond_dead, i);
3426 rcli->condition = ncond;
3427 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3428 REGNO (XEXP (cond, 0)));
3434 /* The register was not previously live at all. Record
3435 the condition under which it is still dead. */
3436 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3437 rcli->condition = not_reg_cond (cond);
3438 rcli->stores = const0_rtx;
3439 rcli->orig_condition = const0_rtx;
3440 splay_tree_insert (pbi->reg_cond_dead, i,
3441 (splay_tree_value) rcli);
3443 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3446 else if (some_was_live)
3448 /* The register may have been conditionally live previously, but
3449 is now unconditionally live. Remove it from the conditionally
3450 dead list, so that a conditional set won't cause us to think
3452 splay_tree_remove (pbi->reg_cond_dead, i);
3458 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3459 This is done assuming the registers needed from X are those that
3460 have 1-bits in PBI->REG_LIVE.
3462 INSN is the containing instruction. If INSN is dead, this function
3466 mark_used_regs (pbi, x, cond, insn)
3467 struct propagate_block_info *pbi;
3470 register RTX_CODE code;
3472 int flags = pbi->flags;
3475 code = GET_CODE (x);
3495 /* If we are clobbering a MEM, mark any registers inside the address
3497 if (GET_CODE (XEXP (x, 0)) == MEM)
3498 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3502 /* Don't bother watching stores to mems if this is not the
3503 final pass. We'll not be deleting dead stores this round. */
3504 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3506 /* Invalidate the data for the last MEM stored, but only if MEM is
3507 something that can be stored into. */
3508 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3509 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3510 /* Needn't clear the memory set list. */
3514 rtx temp = pbi->mem_set_list;
3515 rtx prev = NULL_RTX;
3520 next = XEXP (temp, 1);
3521 if (anti_dependence (XEXP (temp, 0), x))
3523 /* Splice temp out of the list. */
3525 XEXP (prev, 1) = next;
3527 pbi->mem_set_list = next;
3528 free_EXPR_LIST_node (temp);
3529 pbi->mem_set_list_len--;
3537 /* If the memory reference had embedded side effects (autoincrement
3538 address modes. Then we may need to kill some entries on the
3541 invalidate_mems_from_autoinc (pbi, insn);
3545 if (flags & PROP_AUTOINC)
3546 find_auto_inc (pbi, x, insn);
3551 #ifdef CLASS_CANNOT_CHANGE_MODE
3552 if (GET_CODE (SUBREG_REG (x)) == REG
3553 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3554 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3555 GET_MODE (SUBREG_REG (x))))
3556 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3559 /* While we're here, optimize this case. */
3561 if (GET_CODE (x) != REG)
3566 /* See a register other than being set => mark it as needed. */
3567 mark_used_reg (pbi, x, cond, insn);
3572 register rtx testreg = SET_DEST (x);
3575 /* If storing into MEM, don't show it as being used. But do
3576 show the address as being used. */
3577 if (GET_CODE (testreg) == MEM)
3580 if (flags & PROP_AUTOINC)
3581 find_auto_inc (pbi, testreg, insn);
3583 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3584 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3588 /* Storing in STRICT_LOW_PART is like storing in a reg
3589 in that this SET might be dead, so ignore it in TESTREG.
3590 but in some other ways it is like using the reg.
3592 Storing in a SUBREG or a bit field is like storing the entire
3593 register in that if the register's value is not used
3594 then this SET is not needed. */
3595 while (GET_CODE (testreg) == STRICT_LOW_PART
3596 || GET_CODE (testreg) == ZERO_EXTRACT
3597 || GET_CODE (testreg) == SIGN_EXTRACT
3598 || GET_CODE (testreg) == SUBREG)
3600 #ifdef CLASS_CANNOT_CHANGE_MODE
3601 if (GET_CODE (testreg) == SUBREG
3602 && GET_CODE (SUBREG_REG (testreg)) == REG
3603 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3604 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3605 GET_MODE (testreg)))
3606 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3609 /* Modifying a single register in an alternate mode
3610 does not use any of the old value. But these other
3611 ways of storing in a register do use the old value. */
3612 if (GET_CODE (testreg) == SUBREG
3613 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
3618 testreg = XEXP (testreg, 0);
3621 /* If this is a store into a register or group of registers,
3622 recursively scan the value being stored. */
3624 if ((GET_CODE (testreg) == PARALLEL
3625 && GET_MODE (testreg) == BLKmode)
3626 || (GET_CODE (testreg) == REG
3627 && (regno = REGNO (testreg),
3628 ! (regno == FRAME_POINTER_REGNUM
3629 && (! reload_completed || frame_pointer_needed)))
3630 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3631 && ! (regno == HARD_FRAME_POINTER_REGNUM
3632 && (! reload_completed || frame_pointer_needed))
3634 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3635 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3640 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3641 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3648 case UNSPEC_VOLATILE:
3652 /* Traditional and volatile asm instructions must be considered to use
3653 and clobber all hard registers, all pseudo-registers and all of
3654 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3656 Consider for instance a volatile asm that changes the fpu rounding
3657 mode. An insn should not be moved across this even if it only uses
3658 pseudo-regs because it might give an incorrectly rounded result.
3660 ?!? Unfortunately, marking all hard registers as live causes massive
3661 problems for the register allocator and marking all pseudos as live
3662 creates mountains of uninitialized variable warnings.
3664 So for now, just clear the memory set list and mark any regs
3665 we can find in ASM_OPERANDS as used. */
3666 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3668 free_EXPR_LIST_list (&pbi->mem_set_list);
3669 pbi->mem_set_list_len = 0;
3672 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3673 We can not just fall through here since then we would be confused
3674 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3675 traditional asms unlike their normal usage. */
3676 if (code == ASM_OPERANDS)
3680 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3681 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3687 if (cond != NULL_RTX)
3690 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3692 cond = COND_EXEC_TEST (x);
3693 x = COND_EXEC_CODE (x);
3697 /* We _do_not_ want to scan operands of phi nodes. Operands of
3698 a phi function are evaluated only when control reaches this
3699 block along a particular edge. Therefore, regs that appear
3700 as arguments to phi should not be added to the global live at
3708 /* Recursively scan the operands of this expression. */
3711 register const char * const fmt = GET_RTX_FORMAT (code);
3714 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3718 /* Tail recursive case: save a function call level. */
3724 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3726 else if (fmt[i] == 'E')
3729 for (j = 0; j < XVECLEN (x, i); j++)
3730 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3739 try_pre_increment_1 (pbi, insn)
3740 struct propagate_block_info *pbi;
3743 /* Find the next use of this reg. If in same basic block,
3744 make it do pre-increment or pre-decrement if appropriate. */
3745 rtx x = single_set (insn);
3746 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3747 * INTVAL (XEXP (SET_SRC (x), 1)));
3748 int regno = REGNO (SET_DEST (x));
3749 rtx y = pbi->reg_next_use[regno];
3751 && SET_DEST (x) != stack_pointer_rtx
3752 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3753 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3754 mode would be better. */
3755 && ! dead_or_set_p (y, SET_DEST (x))
3756 && try_pre_increment (y, SET_DEST (x), amount))
3758 /* We have found a suitable auto-increment and already changed
3759 insn Y to do it. So flush this increment instruction. */
3760 propagate_block_delete_insn (pbi->bb, insn);
3762 /* Count a reference to this reg for the increment insn we are
3763 deleting. When a reg is incremented, spilling it is worse,
3764 so we want to make that less likely. */
3765 if (regno >= FIRST_PSEUDO_REGISTER)
3767 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3768 REG_N_SETS (regno)++;
3771 /* Flush any remembered memories depending on the value of
3772 the incremented register. */
3773 invalidate_mems_from_set (pbi, SET_DEST (x));
3780 /* Try to change INSN so that it does pre-increment or pre-decrement
3781 addressing on register REG in order to add AMOUNT to REG.
3782 AMOUNT is negative for pre-decrement.
3783 Returns 1 if the change could be made.
3784 This checks all about the validity of the result of modifying INSN. */
3787 try_pre_increment (insn, reg, amount)
3789 HOST_WIDE_INT amount;
3793 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3794 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3796 /* Nonzero if we can try to make a post-increment or post-decrement.
3797 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3798 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3799 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3802 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3805 /* From the sign of increment, see which possibilities are conceivable
3806 on this target machine. */
3807 if (HAVE_PRE_INCREMENT && amount > 0)
3809 if (HAVE_POST_INCREMENT && amount > 0)
3812 if (HAVE_PRE_DECREMENT && amount < 0)
3814 if (HAVE_POST_DECREMENT && amount < 0)
3817 if (! (pre_ok || post_ok))
3820 /* It is not safe to add a side effect to a jump insn
3821 because if the incremented register is spilled and must be reloaded
3822 there would be no way to store the incremented value back in memory. */
3824 if (GET_CODE (insn) == JUMP_INSN)
3829 use = find_use_as_address (PATTERN (insn), reg, 0);
3830 if (post_ok && (use == 0 || use == (rtx) 1))
3832 use = find_use_as_address (PATTERN (insn), reg, -amount);
3836 if (use == 0 || use == (rtx) 1)
3839 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
3842 /* See if this combination of instruction and addressing mode exists. */
3843 if (! validate_change (insn, &XEXP (use, 0),
3844 gen_rtx_fmt_e (amount > 0
3845 ? (do_post ? POST_INC : PRE_INC)
3846 : (do_post ? POST_DEC : PRE_DEC),
3850 /* Record that this insn now has an implicit side effect on X. */
3851 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
3855 #endif /* AUTO_INC_DEC */
3857 /* Find the place in the rtx X where REG is used as a memory address.
3858 Return the MEM rtx that so uses it.
3859 If PLUSCONST is nonzero, search instead for a memory address equivalent to
3860 (plus REG (const_int PLUSCONST)).
3862 If such an address does not appear, return 0.
3863 If REG appears more than once, or is used other than in such an address,
3867 find_use_as_address (x, reg, plusconst)
3870 HOST_WIDE_INT plusconst;
3872 enum rtx_code code = GET_CODE (x);
3873 const char * const fmt = GET_RTX_FORMAT (code);
3875 register rtx value = 0;
3878 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
3881 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
3882 && XEXP (XEXP (x, 0), 0) == reg
3883 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
3884 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
3887 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
3889 /* If REG occurs inside a MEM used in a bit-field reference,
3890 that is unacceptable. */
3891 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
3892 return (rtx) (HOST_WIDE_INT) 1;
3896 return (rtx) (HOST_WIDE_INT) 1;
3898 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3902 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
3906 return (rtx) (HOST_WIDE_INT) 1;
3908 else if (fmt[i] == 'E')
3911 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3913 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
3917 return (rtx) (HOST_WIDE_INT) 1;
3925 /* Write information about registers and basic blocks into FILE.
3926 This is part of making a debugging dump. */
3929 dump_regset (r, outf)
3936 fputs (" (nil)", outf);
3940 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
3942 fprintf (outf, " %d", i);
3943 if (i < FIRST_PSEUDO_REGISTER)
3944 fprintf (outf, " [%s]",
3949 /* Print a human-reaable representation of R on the standard error
3950 stream. This function is designed to be used from within the
3957 dump_regset (r, stderr);
3958 putc ('\n', stderr);
3961 /* Dump the rtl into the current debugging dump file, then abort. */
3964 print_rtl_and_abort_fcn (file, line, function)
3967 const char *function;
3971 print_rtl_with_bb (rtl_dump_file, get_insns ());
3972 fclose (rtl_dump_file);
3975 fancy_abort (file, line, function);
3978 /* Recompute register set/reference counts immediately prior to register
3981 This avoids problems with set/reference counts changing to/from values
3982 which have special meanings to the register allocators.
3984 Additionally, the reference counts are the primary component used by the
3985 register allocators to prioritize pseudos for allocation to hard regs.
3986 More accurate reference counts generally lead to better register allocation.
3988 F is the first insn to be scanned.
3990 LOOP_STEP denotes how much loop_depth should be incremented per
3991 loop nesting level in order to increase the ref count more for
3992 references in a loop.
3994 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
3995 possibly other information which is used by the register allocators. */
3998 recompute_reg_usage (f, loop_step)
3999 rtx f ATTRIBUTE_UNUSED;
4000 int loop_step ATTRIBUTE_UNUSED;
4002 allocate_reg_life_data ();
4003 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4006 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4007 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4008 of the number of registers that died. */
4011 count_or_remove_death_notes (blocks, kill)
4017 for (i = n_basic_blocks - 1; i >= 0; --i)
4022 if (blocks && ! TEST_BIT (blocks, i))
4025 bb = BASIC_BLOCK (i);
4027 for (insn = bb->head;; insn = NEXT_INSN (insn))
4031 rtx *pprev = ®_NOTES (insn);
4036 switch (REG_NOTE_KIND (link))
4039 if (GET_CODE (XEXP (link, 0)) == REG)
4041 rtx reg = XEXP (link, 0);
4044 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4047 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4055 rtx next = XEXP (link, 1);
4056 free_EXPR_LIST_node (link);
4057 *pprev = link = next;
4063 pprev = &XEXP (link, 1);
4070 if (insn == bb->end)
4077 /* Clear LOG_LINKS fields of insns in a chain.
4078 Also clear the global_live_at_{start,end} fields of the basic block
4082 clear_log_links (insns)
4088 for (i = insns; i; i = NEXT_INSN (i))
4092 for (b = 0; b < n_basic_blocks; b++)
4094 basic_block bb = BASIC_BLOCK (b);
4096 bb->global_live_at_start = NULL;
4097 bb->global_live_at_end = NULL;
4100 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
4101 EXIT_BLOCK_PTR->global_live_at_start = NULL;
4104 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4105 correspond to the hard registers, if any, set in that map. This
4106 could be done far more efficiently by having all sorts of special-cases
4107 with moving single words, but probably isn't worth the trouble. */
4110 reg_set_to_hard_reg_set (to, from)
4116 EXECUTE_IF_SET_IN_BITMAP
4119 if (i >= FIRST_PSEUDO_REGISTER)
4121 SET_HARD_REG_BIT (*to, i);