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 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) == LABEL_PRESERVE_P (insn)
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 delete_insn (NEXT_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);
1328 /* If the insn referred to a label, and that label was attached to
1329 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1330 pretty much mandatory to delete it, because the ADDR_VEC may be
1331 referencing labels that no longer exist.
1333 INSN may reference a deleted label, particularly when a jump
1334 table has been optimized into a direct jump. There's no
1335 real good way to fix up the reference to the deleted label
1336 when the label is deleted, so we just allow it here.
1338 After dead code elimination is complete, we do search for
1339 any REG_LABEL notes which reference deleted labels as a
1342 if (inote && GET_CODE (inote) == CODE_LABEL)
1344 rtx label = XEXP (inote, 0);
1347 /* The label may be forced if it has been put in the constant
1348 pool. If that is the only use we must discard the table
1349 jump following it, but not the label itself. */
1350 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1351 && (next = next_nonnote_insn (label)) != NULL
1352 && GET_CODE (next) == JUMP_INSN
1353 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1354 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1356 rtx pat = PATTERN (next);
1357 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1358 int len = XVECLEN (pat, diff_vec_p);
1361 for (i = 0; i < len; i++)
1362 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1368 if (bb->end == insn)
1372 purge_dead_edges (bb);
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 delete_insn_chain (first, insn);
1390 /* Update the life-status of regs for one insn. Return the previous insn. */
1393 propagate_one_insn (pbi, insn)
1394 struct propagate_block_info *pbi;
1397 rtx prev = PREV_INSN (insn);
1398 int flags = pbi->flags;
1399 int insn_is_dead = 0;
1400 int libcall_is_dead = 0;
1404 if (! INSN_P (insn))
1407 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1408 if (flags & PROP_SCAN_DEAD_CODE)
1410 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1411 libcall_is_dead = (insn_is_dead && note != 0
1412 && libcall_dead_p (pbi, note, insn));
1415 /* If an instruction consists of just dead store(s) on final pass,
1417 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1419 /* If we're trying to delete a prologue or epilogue instruction
1420 that isn't flagged as possibly being dead, something is wrong.
1421 But if we are keeping the stack pointer depressed, we might well
1422 be deleting insns that are used to compute the amount to update
1423 it by, so they are fine. */
1424 if (reload_completed
1425 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1426 && (TYPE_RETURNS_STACK_DEPRESSED
1427 (TREE_TYPE (current_function_decl))))
1428 && (((HAVE_epilogue || HAVE_prologue)
1429 && prologue_epilogue_contains (insn))
1430 || (HAVE_sibcall_epilogue
1431 && sibcall_epilogue_contains (insn)))
1432 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1435 /* Record sets. Do this even for dead instructions, since they
1436 would have killed the values if they hadn't been deleted. */
1437 mark_set_regs (pbi, PATTERN (insn), insn);
1439 /* CC0 is now known to be dead. Either this insn used it,
1440 in which case it doesn't anymore, or clobbered it,
1441 so the next insn can't use it. */
1444 if (libcall_is_dead)
1445 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
1447 propagate_block_delete_insn (pbi->bb, insn);
1452 /* See if this is an increment or decrement that can be merged into
1453 a following memory address. */
1456 register rtx x = single_set (insn);
1458 /* Does this instruction increment or decrement a register? */
1459 if ((flags & PROP_AUTOINC)
1461 && GET_CODE (SET_DEST (x)) == REG
1462 && (GET_CODE (SET_SRC (x)) == PLUS
1463 || GET_CODE (SET_SRC (x)) == MINUS)
1464 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1465 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1466 /* Ok, look for a following memory ref we can combine with.
1467 If one is found, change the memory ref to a PRE_INC
1468 or PRE_DEC, cancel this insn, and return 1.
1469 Return 0 if nothing has been done. */
1470 && try_pre_increment_1 (pbi, insn))
1473 #endif /* AUTO_INC_DEC */
1475 CLEAR_REG_SET (pbi->new_set);
1477 /* If this is not the final pass, and this insn is copying the value of
1478 a library call and it's dead, don't scan the insns that perform the
1479 library call, so that the call's arguments are not marked live. */
1480 if (libcall_is_dead)
1482 /* Record the death of the dest reg. */
1483 mark_set_regs (pbi, PATTERN (insn), insn);
1485 insn = XEXP (note, 0);
1486 return PREV_INSN (insn);
1488 else if (GET_CODE (PATTERN (insn)) == SET
1489 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1490 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1491 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1492 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1493 /* We have an insn to pop a constant amount off the stack.
1494 (Such insns use PLUS regardless of the direction of the stack,
1495 and any insn to adjust the stack by a constant is always a pop.)
1496 These insns, if not dead stores, have no effect on life. */
1500 /* Any regs live at the time of a call instruction must not go
1501 in a register clobbered by calls. Find all regs now live and
1502 record this for them. */
1504 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1505 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1506 { REG_N_CALLS_CROSSED (i)++; });
1508 /* Record sets. Do this even for dead instructions, since they
1509 would have killed the values if they hadn't been deleted. */
1510 mark_set_regs (pbi, PATTERN (insn), insn);
1512 if (GET_CODE (insn) == CALL_INSN)
1518 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1519 cond = COND_EXEC_TEST (PATTERN (insn));
1521 /* Non-constant calls clobber memory. */
1522 if (! CONST_OR_PURE_CALL_P (insn))
1524 free_EXPR_LIST_list (&pbi->mem_set_list);
1525 pbi->mem_set_list_len = 0;
1528 /* There may be extra registers to be clobbered. */
1529 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1531 note = XEXP (note, 1))
1532 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1533 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1534 cond, insn, pbi->flags);
1536 /* Calls change all call-used and global registers. */
1537 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1538 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1540 /* We do not want REG_UNUSED notes for these registers. */
1541 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1543 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1547 /* If an insn doesn't use CC0, it becomes dead since we assume
1548 that every insn clobbers it. So show it dead here;
1549 mark_used_regs will set it live if it is referenced. */
1554 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1556 /* Sometimes we may have inserted something before INSN (such as a move)
1557 when we make an auto-inc. So ensure we will scan those insns. */
1559 prev = PREV_INSN (insn);
1562 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1568 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1569 cond = COND_EXEC_TEST (PATTERN (insn));
1571 /* Calls use their arguments. */
1572 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1574 note = XEXP (note, 1))
1575 if (GET_CODE (XEXP (note, 0)) == USE)
1576 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1579 /* The stack ptr is used (honorarily) by a CALL insn. */
1580 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1582 /* Calls may also reference any of the global registers,
1583 so they are made live. */
1584 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1586 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1591 /* On final pass, update counts of how many insns in which each reg
1593 if (flags & PROP_REG_INFO)
1594 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1595 { REG_LIVE_LENGTH (i)++; });
1600 /* Initialize a propagate_block_info struct for public consumption.
1601 Note that the structure itself is opaque to this file, but that
1602 the user can use the regsets provided here. */
1604 struct propagate_block_info *
1605 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1607 regset live, local_set, cond_local_set;
1610 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1613 pbi->reg_live = live;
1614 pbi->mem_set_list = NULL_RTX;
1615 pbi->mem_set_list_len = 0;
1616 pbi->local_set = local_set;
1617 pbi->cond_local_set = cond_local_set;
1621 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1622 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1624 pbi->reg_next_use = NULL;
1626 pbi->new_set = BITMAP_XMALLOC ();
1628 #ifdef HAVE_conditional_execution
1629 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1630 free_reg_cond_life_info);
1631 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1633 /* If this block ends in a conditional branch, for each register live
1634 from one side of the branch and not the other, record the register
1635 as conditionally dead. */
1636 if (GET_CODE (bb->end) == JUMP_INSN
1637 && any_condjump_p (bb->end))
1639 regset_head diff_head;
1640 regset diff = INITIALIZE_REG_SET (diff_head);
1641 basic_block bb_true, bb_false;
1642 rtx cond_true, cond_false, set_src;
1645 /* Identify the successor blocks. */
1646 bb_true = bb->succ->dest;
1647 if (bb->succ->succ_next != NULL)
1649 bb_false = bb->succ->succ_next->dest;
1651 if (bb->succ->flags & EDGE_FALLTHRU)
1653 basic_block t = bb_false;
1657 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1662 /* This can happen with a conditional jump to the next insn. */
1663 if (JUMP_LABEL (bb->end) != bb_true->head)
1666 /* Simplest way to do nothing. */
1670 /* Extract the condition from the branch. */
1671 set_src = SET_SRC (pc_set (bb->end));
1672 cond_true = XEXP (set_src, 0);
1673 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1674 GET_MODE (cond_true), XEXP (cond_true, 0),
1675 XEXP (cond_true, 1));
1676 if (GET_CODE (XEXP (set_src, 1)) == PC)
1679 cond_false = cond_true;
1683 /* Compute which register lead different lives in the successors. */
1684 if (bitmap_operation (diff, bb_true->global_live_at_start,
1685 bb_false->global_live_at_start, BITMAP_XOR))
1687 rtx reg = XEXP (cond_true, 0);
1689 if (GET_CODE (reg) == SUBREG)
1690 reg = SUBREG_REG (reg);
1692 if (GET_CODE (reg) != REG)
1695 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1697 /* For each such register, mark it conditionally dead. */
1698 EXECUTE_IF_SET_IN_REG_SET
1701 struct reg_cond_life_info *rcli;
1704 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1706 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1710 rcli->condition = cond;
1711 rcli->stores = const0_rtx;
1712 rcli->orig_condition = cond;
1714 splay_tree_insert (pbi->reg_cond_dead, i,
1715 (splay_tree_value) rcli);
1719 FREE_REG_SET (diff);
1723 /* If this block has no successors, any stores to the frame that aren't
1724 used later in the block are dead. So make a pass over the block
1725 recording any such that are made and show them dead at the end. We do
1726 a very conservative and simple job here. */
1728 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1729 && (TYPE_RETURNS_STACK_DEPRESSED
1730 (TREE_TYPE (current_function_decl))))
1731 && (flags & PROP_SCAN_DEAD_CODE)
1732 && (bb->succ == NULL
1733 || (bb->succ->succ_next == NULL
1734 && bb->succ->dest == EXIT_BLOCK_PTR
1735 && ! current_function_calls_eh_return)))
1738 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1739 if (GET_CODE (insn) == INSN
1740 && (set = single_set (insn))
1741 && GET_CODE (SET_DEST (set)) == MEM)
1743 rtx mem = SET_DEST (set);
1744 rtx canon_mem = canon_rtx (mem);
1746 /* This optimization is performed by faking a store to the
1747 memory at the end of the block. This doesn't work for
1748 unchanging memories because multiple stores to unchanging
1749 memory is illegal and alias analysis doesn't consider it. */
1750 if (RTX_UNCHANGING_P (canon_mem))
1753 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1754 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1755 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1756 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1757 add_to_mem_set_list (pbi, canon_mem);
1764 /* Release a propagate_block_info struct. */
1767 free_propagate_block_info (pbi)
1768 struct propagate_block_info *pbi;
1770 free_EXPR_LIST_list (&pbi->mem_set_list);
1772 BITMAP_XFREE (pbi->new_set);
1774 #ifdef HAVE_conditional_execution
1775 splay_tree_delete (pbi->reg_cond_dead);
1776 BITMAP_XFREE (pbi->reg_cond_reg);
1779 if (pbi->reg_next_use)
1780 free (pbi->reg_next_use);
1785 /* Compute the registers live at the beginning of a basic block BB from
1786 those live at the end.
1788 When called, REG_LIVE contains those live at the end. On return, it
1789 contains those live at the beginning.
1791 LOCAL_SET, if non-null, will be set with all registers killed
1792 unconditionally by this basic block.
1793 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1794 killed conditionally by this basic block. If there is any unconditional
1795 set of a register, then the corresponding bit will be set in LOCAL_SET
1796 and cleared in COND_LOCAL_SET.
1797 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1798 case, the resulting set will be equal to the union of the two sets that
1799 would otherwise be computed.
1801 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1804 propagate_block (bb, live, local_set, cond_local_set, flags)
1808 regset cond_local_set;
1811 struct propagate_block_info *pbi;
1815 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
1817 if (flags & PROP_REG_INFO)
1821 /* Process the regs live at the end of the block.
1822 Mark them as not local to any one basic block. */
1823 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
1824 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
1827 /* Scan the block an insn at a time from end to beginning. */
1830 for (insn = bb->end;; insn = prev)
1832 /* If this is a call to `setjmp' et al, warn if any
1833 non-volatile datum is live. */
1834 if ((flags & PROP_REG_INFO)
1835 && GET_CODE (insn) == CALL_INSN
1836 && find_reg_note (insn, REG_SETJMP, NULL))
1837 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
1839 prev = propagate_one_insn (pbi, insn);
1840 changed |= NEXT_INSN (prev) != insn;
1842 if (insn == bb->head)
1846 free_propagate_block_info (pbi);
1851 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1852 (SET expressions whose destinations are registers dead after the insn).
1853 NEEDED is the regset that says which regs are alive after the insn.
1855 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1857 If X is the entire body of an insn, NOTES contains the reg notes
1858 pertaining to the insn. */
1861 insn_dead_p (pbi, x, call_ok, notes)
1862 struct propagate_block_info *pbi;
1865 rtx notes ATTRIBUTE_UNUSED;
1867 enum rtx_code code = GET_CODE (x);
1870 /* If flow is invoked after reload, we must take existing AUTO_INC
1871 expresions into account. */
1872 if (reload_completed)
1874 for (; notes; notes = XEXP (notes, 1))
1876 if (REG_NOTE_KIND (notes) == REG_INC)
1878 int regno = REGNO (XEXP (notes, 0));
1880 /* Don't delete insns to set global regs. */
1881 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1882 || REGNO_REG_SET_P (pbi->reg_live, regno))
1889 /* If setting something that's a reg or part of one,
1890 see if that register's altered value will be live. */
1894 rtx r = SET_DEST (x);
1897 if (GET_CODE (r) == CC0)
1898 return ! pbi->cc0_live;
1901 /* A SET that is a subroutine call cannot be dead. */
1902 if (GET_CODE (SET_SRC (x)) == CALL)
1908 /* Don't eliminate loads from volatile memory or volatile asms. */
1909 else if (volatile_refs_p (SET_SRC (x)))
1912 if (GET_CODE (r) == MEM)
1916 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
1919 canon_r = canon_rtx (r);
1921 /* Walk the set of memory locations we are currently tracking
1922 and see if one is an identical match to this memory location.
1923 If so, this memory write is dead (remember, we're walking
1924 backwards from the end of the block to the start). Since
1925 rtx_equal_p does not check the alias set or flags, we also
1926 must have the potential for them to conflict (anti_dependence). */
1927 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
1928 if (anti_dependence (r, XEXP (temp, 0)))
1930 rtx mem = XEXP (temp, 0);
1932 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
1933 && (GET_MODE_SIZE (GET_MODE (canon_r))
1934 <= GET_MODE_SIZE (GET_MODE (mem))))
1938 /* Check if memory reference matches an auto increment. Only
1939 post increment/decrement or modify are valid. */
1940 if (GET_MODE (mem) == GET_MODE (r)
1941 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
1942 || GET_CODE (XEXP (mem, 0)) == POST_INC
1943 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
1944 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
1945 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
1952 while (GET_CODE (r) == SUBREG
1953 || GET_CODE (r) == STRICT_LOW_PART
1954 || GET_CODE (r) == ZERO_EXTRACT)
1957 if (GET_CODE (r) == REG)
1959 int regno = REGNO (r);
1962 if (REGNO_REG_SET_P (pbi->reg_live, regno))
1965 /* If this is a hard register, verify that subsequent
1966 words are not needed. */
1967 if (regno < FIRST_PSEUDO_REGISTER)
1969 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
1972 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
1976 /* Don't delete insns to set global regs. */
1977 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1980 /* Make sure insns to set the stack pointer aren't deleted. */
1981 if (regno == STACK_POINTER_REGNUM)
1984 /* ??? These bits might be redundant with the force live bits
1985 in calculate_global_regs_live. We would delete from
1986 sequential sets; whether this actually affects real code
1987 for anything but the stack pointer I don't know. */
1988 /* Make sure insns to set the frame pointer aren't deleted. */
1989 if (regno == FRAME_POINTER_REGNUM
1990 && (! reload_completed || frame_pointer_needed))
1992 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
1993 if (regno == HARD_FRAME_POINTER_REGNUM
1994 && (! reload_completed || frame_pointer_needed))
1998 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1999 /* Make sure insns to set arg pointer are never deleted
2000 (if the arg pointer isn't fixed, there will be a USE
2001 for it, so we can treat it normally). */
2002 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2006 /* Otherwise, the set is dead. */
2012 /* If performing several activities, insn is dead if each activity
2013 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2014 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2016 else if (code == PARALLEL)
2018 int i = XVECLEN (x, 0);
2020 for (i--; i >= 0; i--)
2021 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2022 && GET_CODE (XVECEXP (x, 0, i)) != USE
2023 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2029 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2030 is not necessarily true for hard registers. */
2031 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2032 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2033 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2036 /* We do not check other CLOBBER or USE here. An insn consisting of just
2037 a CLOBBER or just a USE should not be deleted. */
2041 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2042 return 1 if the entire library call is dead.
2043 This is true if INSN copies a register (hard or pseudo)
2044 and if the hard return reg of the call insn is dead.
2045 (The caller should have tested the destination of the SET inside
2046 INSN already for death.)
2048 If this insn doesn't just copy a register, then we don't
2049 have an ordinary libcall. In that case, cse could not have
2050 managed to substitute the source for the dest later on,
2051 so we can assume the libcall is dead.
2053 PBI is the block info giving pseudoregs live before this insn.
2054 NOTE is the REG_RETVAL note of the insn. */
2057 libcall_dead_p (pbi, note, insn)
2058 struct propagate_block_info *pbi;
2062 rtx x = single_set (insn);
2066 register rtx r = SET_SRC (x);
2068 if (GET_CODE (r) == REG)
2070 rtx call = XEXP (note, 0);
2074 /* Find the call insn. */
2075 while (call != insn && GET_CODE (call) != CALL_INSN)
2076 call = NEXT_INSN (call);
2078 /* If there is none, do nothing special,
2079 since ordinary death handling can understand these insns. */
2083 /* See if the hard reg holding the value is dead.
2084 If this is a PARALLEL, find the call within it. */
2085 call_pat = PATTERN (call);
2086 if (GET_CODE (call_pat) == PARALLEL)
2088 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2089 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2090 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2093 /* This may be a library call that is returning a value
2094 via invisible pointer. Do nothing special, since
2095 ordinary death handling can understand these insns. */
2099 call_pat = XVECEXP (call_pat, 0, i);
2102 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2108 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2109 live at function entry. Don't count global register variables, variables
2110 in registers that can be used for function arg passing, or variables in
2111 fixed hard registers. */
2114 regno_uninitialized (regno)
2117 if (n_basic_blocks == 0
2118 || (regno < FIRST_PSEUDO_REGISTER
2119 && (global_regs[regno]
2120 || fixed_regs[regno]
2121 || FUNCTION_ARG_REGNO_P (regno))))
2124 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
2127 /* 1 if register REGNO was alive at a place where `setjmp' was called
2128 and was set more than once or is an argument.
2129 Such regs may be clobbered by `longjmp'. */
2132 regno_clobbered_at_setjmp (regno)
2135 if (n_basic_blocks == 0)
2138 return ((REG_N_SETS (regno) > 1
2139 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
2140 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2143 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2144 maximal list size; look for overlaps in mode and select the largest. */
2146 add_to_mem_set_list (pbi, mem)
2147 struct propagate_block_info *pbi;
2152 /* We don't know how large a BLKmode store is, so we must not
2153 take them into consideration. */
2154 if (GET_MODE (mem) == BLKmode)
2157 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2159 rtx e = XEXP (i, 0);
2160 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2162 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2165 /* If we must store a copy of the mem, we can just modify
2166 the mode of the stored copy. */
2167 if (pbi->flags & PROP_AUTOINC)
2168 PUT_MODE (e, GET_MODE (mem));
2177 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2180 /* Store a copy of mem, otherwise the address may be
2181 scrogged by find_auto_inc. */
2182 if (pbi->flags & PROP_AUTOINC)
2183 mem = shallow_copy_rtx (mem);
2185 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2186 pbi->mem_set_list_len++;
2190 /* INSN references memory, possibly using autoincrement addressing modes.
2191 Find any entries on the mem_set_list that need to be invalidated due
2192 to an address change. */
2195 invalidate_mems_from_autoinc (pbi, insn)
2196 struct propagate_block_info *pbi;
2199 rtx note = REG_NOTES (insn);
2200 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2201 if (REG_NOTE_KIND (note) == REG_INC)
2202 invalidate_mems_from_set (pbi, XEXP (note, 0));
2205 /* EXP is a REG. Remove any dependant entries from pbi->mem_set_list. */
2208 invalidate_mems_from_set (pbi, exp)
2209 struct propagate_block_info *pbi;
2212 rtx temp = pbi->mem_set_list;
2213 rtx prev = NULL_RTX;
2218 next = XEXP (temp, 1);
2219 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2221 /* Splice this entry out of the list. */
2223 XEXP (prev, 1) = next;
2225 pbi->mem_set_list = next;
2226 free_EXPR_LIST_node (temp);
2227 pbi->mem_set_list_len--;
2235 /* Process the registers that are set within X. Their bits are set to
2236 1 in the regset DEAD, because they are dead prior to this insn.
2238 If INSN is nonzero, it is the insn being processed.
2240 FLAGS is the set of operations to perform. */
2243 mark_set_regs (pbi, x, insn)
2244 struct propagate_block_info *pbi;
2247 rtx cond = NULL_RTX;
2252 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2254 if (REG_NOTE_KIND (link) == REG_INC)
2255 mark_set_1 (pbi, SET, XEXP (link, 0),
2256 (GET_CODE (x) == COND_EXEC
2257 ? COND_EXEC_TEST (x) : NULL_RTX),
2261 switch (code = GET_CODE (x))
2265 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2269 cond = COND_EXEC_TEST (x);
2270 x = COND_EXEC_CODE (x);
2276 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2278 rtx sub = XVECEXP (x, 0, i);
2279 switch (code = GET_CODE (sub))
2282 if (cond != NULL_RTX)
2285 cond = COND_EXEC_TEST (sub);
2286 sub = COND_EXEC_CODE (sub);
2287 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2293 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2308 /* Process a single set, which appears in INSN. REG (which may not
2309 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2310 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2311 If the set is conditional (because it appear in a COND_EXEC), COND
2312 will be the condition. */
2315 mark_set_1 (pbi, code, reg, cond, insn, flags)
2316 struct propagate_block_info *pbi;
2318 rtx reg, cond, insn;
2321 int regno_first = -1, regno_last = -1;
2322 unsigned long not_dead = 0;
2325 /* Modifying just one hardware register of a multi-reg value or just a
2326 byte field of a register does not mean the value from before this insn
2327 is now dead. Of course, if it was dead after it's unused now. */
2329 switch (GET_CODE (reg))
2332 /* Some targets place small structures in registers for return values of
2333 functions. We have to detect this case specially here to get correct
2334 flow information. */
2335 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2336 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2337 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2343 case STRICT_LOW_PART:
2344 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2346 reg = XEXP (reg, 0);
2347 while (GET_CODE (reg) == SUBREG
2348 || GET_CODE (reg) == ZERO_EXTRACT
2349 || GET_CODE (reg) == SIGN_EXTRACT
2350 || GET_CODE (reg) == STRICT_LOW_PART);
2351 if (GET_CODE (reg) == MEM)
2353 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2357 regno_last = regno_first = REGNO (reg);
2358 if (regno_first < FIRST_PSEUDO_REGISTER)
2359 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2363 if (GET_CODE (SUBREG_REG (reg)) == REG)
2365 enum machine_mode outer_mode = GET_MODE (reg);
2366 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2368 /* Identify the range of registers affected. This is moderately
2369 tricky for hard registers. See alter_subreg. */
2371 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2372 if (regno_first < FIRST_PSEUDO_REGISTER)
2374 regno_first += subreg_regno_offset (regno_first, inner_mode,
2377 regno_last = (regno_first
2378 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2380 /* Since we've just adjusted the register number ranges, make
2381 sure REG matches. Otherwise some_was_live will be clear
2382 when it shouldn't have been, and we'll create incorrect
2383 REG_UNUSED notes. */
2384 reg = gen_rtx_REG (outer_mode, regno_first);
2388 /* If the number of words in the subreg is less than the number
2389 of words in the full register, we have a well-defined partial
2390 set. Otherwise the high bits are undefined.
2392 This is only really applicable to pseudos, since we just took
2393 care of multi-word hard registers. */
2394 if (((GET_MODE_SIZE (outer_mode)
2395 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2396 < ((GET_MODE_SIZE (inner_mode)
2397 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2398 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2401 reg = SUBREG_REG (reg);
2405 reg = SUBREG_REG (reg);
2412 /* If this set is a MEM, then it kills any aliased writes.
2413 If this set is a REG, then it kills any MEMs which use the reg. */
2414 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2416 if (GET_CODE (reg) == REG)
2417 invalidate_mems_from_set (pbi, reg);
2419 /* If the memory reference had embedded side effects (autoincrement
2420 address modes. Then we may need to kill some entries on the
2422 if (insn && GET_CODE (reg) == MEM)
2423 invalidate_mems_from_autoinc (pbi, insn);
2425 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2426 /* ??? With more effort we could track conditional memory life. */
2428 /* There are no REG_INC notes for SP, so we can't assume we'll see
2429 everything that invalidates it. To be safe, don't eliminate any
2430 stores though SP; none of them should be redundant anyway. */
2431 && ! reg_mentioned_p (stack_pointer_rtx, reg))
2432 add_to_mem_set_list (pbi, canon_rtx (reg));
2435 if (GET_CODE (reg) == REG
2436 && ! (regno_first == FRAME_POINTER_REGNUM
2437 && (! reload_completed || frame_pointer_needed))
2438 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2439 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2440 && (! reload_completed || frame_pointer_needed))
2442 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2443 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2447 int some_was_live = 0, some_was_dead = 0;
2449 for (i = regno_first; i <= regno_last; ++i)
2451 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2454 /* Order of the set operation matters here since both
2455 sets may be the same. */
2456 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2457 if (cond != NULL_RTX
2458 && ! REGNO_REG_SET_P (pbi->local_set, i))
2459 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2461 SET_REGNO_REG_SET (pbi->local_set, i);
2463 if (code != CLOBBER)
2464 SET_REGNO_REG_SET (pbi->new_set, i);
2466 some_was_live |= needed_regno;
2467 some_was_dead |= ! needed_regno;
2470 #ifdef HAVE_conditional_execution
2471 /* Consider conditional death in deciding that the register needs
2473 if (some_was_live && ! not_dead
2474 /* The stack pointer is never dead. Well, not strictly true,
2475 but it's very difficult to tell from here. Hopefully
2476 combine_stack_adjustments will fix up the most egregious
2478 && regno_first != STACK_POINTER_REGNUM)
2480 for (i = regno_first; i <= regno_last; ++i)
2481 if (! mark_regno_cond_dead (pbi, i, cond))
2482 not_dead |= ((unsigned long) 1) << (i - regno_first);
2486 /* Additional data to record if this is the final pass. */
2487 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2488 | PROP_DEATH_NOTES | PROP_AUTOINC))
2491 register int blocknum = pbi->bb->index;
2494 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2496 y = pbi->reg_next_use[regno_first];
2498 /* The next use is no longer next, since a store intervenes. */
2499 for (i = regno_first; i <= regno_last; ++i)
2500 pbi->reg_next_use[i] = 0;
2503 if (flags & PROP_REG_INFO)
2505 for (i = regno_first; i <= regno_last; ++i)
2507 /* Count (weighted) references, stores, etc. This counts a
2508 register twice if it is modified, but that is correct. */
2509 REG_N_SETS (i) += 1;
2510 REG_N_REFS (i) += 1;
2511 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2513 /* The insns where a reg is live are normally counted
2514 elsewhere, but we want the count to include the insn
2515 where the reg is set, and the normal counting mechanism
2516 would not count it. */
2517 REG_LIVE_LENGTH (i) += 1;
2520 /* If this is a hard reg, record this function uses the reg. */
2521 if (regno_first < FIRST_PSEUDO_REGISTER)
2523 for (i = regno_first; i <= regno_last; i++)
2524 regs_ever_live[i] = 1;
2528 /* Keep track of which basic blocks each reg appears in. */
2529 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2530 REG_BASIC_BLOCK (regno_first) = blocknum;
2531 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2532 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2536 if (! some_was_dead)
2538 if (flags & PROP_LOG_LINKS)
2540 /* Make a logical link from the next following insn
2541 that uses this register, back to this insn.
2542 The following insns have already been processed.
2544 We don't build a LOG_LINK for hard registers containing
2545 in ASM_OPERANDs. If these registers get replaced,
2546 we might wind up changing the semantics of the insn,
2547 even if reload can make what appear to be valid
2548 assignments later. */
2549 if (y && (BLOCK_NUM (y) == blocknum)
2550 && (regno_first >= FIRST_PSEUDO_REGISTER
2551 || asm_noperands (PATTERN (y)) < 0))
2552 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2557 else if (! some_was_live)
2559 if (flags & PROP_REG_INFO)
2560 REG_N_DEATHS (regno_first) += 1;
2562 if (flags & PROP_DEATH_NOTES)
2564 /* Note that dead stores have already been deleted
2565 when possible. If we get here, we have found a
2566 dead store that cannot be eliminated (because the
2567 same insn does something useful). Indicate this
2568 by marking the reg being set as dying here. */
2570 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2575 if (flags & PROP_DEATH_NOTES)
2577 /* This is a case where we have a multi-word hard register
2578 and some, but not all, of the words of the register are
2579 needed in subsequent insns. Write REG_UNUSED notes
2580 for those parts that were not needed. This case should
2583 for (i = regno_first; i <= regno_last; ++i)
2584 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2586 = alloc_EXPR_LIST (REG_UNUSED,
2587 gen_rtx_REG (reg_raw_mode[i], i),
2593 /* Mark the register as being dead. */
2595 /* The stack pointer is never dead. Well, not strictly true,
2596 but it's very difficult to tell from here. Hopefully
2597 combine_stack_adjustments will fix up the most egregious
2599 && regno_first != STACK_POINTER_REGNUM)
2601 for (i = regno_first; i <= regno_last; ++i)
2602 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2603 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2606 else if (GET_CODE (reg) == REG)
2608 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2609 pbi->reg_next_use[regno_first] = 0;
2612 /* If this is the last pass and this is a SCRATCH, show it will be dying
2613 here and count it. */
2614 else if (GET_CODE (reg) == SCRATCH)
2616 if (flags & PROP_DEATH_NOTES)
2618 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2622 #ifdef HAVE_conditional_execution
2623 /* Mark REGNO conditionally dead.
2624 Return true if the register is now unconditionally dead. */
2627 mark_regno_cond_dead (pbi, regno, cond)
2628 struct propagate_block_info *pbi;
2632 /* If this is a store to a predicate register, the value of the
2633 predicate is changing, we don't know that the predicate as seen
2634 before is the same as that seen after. Flush all dependent
2635 conditions from reg_cond_dead. This will make all such
2636 conditionally live registers unconditionally live. */
2637 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2638 flush_reg_cond_reg (pbi, regno);
2640 /* If this is an unconditional store, remove any conditional
2641 life that may have existed. */
2642 if (cond == NULL_RTX)
2643 splay_tree_remove (pbi->reg_cond_dead, regno);
2646 splay_tree_node node;
2647 struct reg_cond_life_info *rcli;
2650 /* Otherwise this is a conditional set. Record that fact.
2651 It may have been conditionally used, or there may be a
2652 subsequent set with a complimentary condition. */
2654 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2657 /* The register was unconditionally live previously.
2658 Record the current condition as the condition under
2659 which it is dead. */
2660 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2661 rcli->condition = cond;
2662 rcli->stores = cond;
2663 rcli->orig_condition = const0_rtx;
2664 splay_tree_insert (pbi->reg_cond_dead, regno,
2665 (splay_tree_value) rcli);
2667 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2669 /* Not unconditionaly dead. */
2674 /* The register was conditionally live previously.
2675 Add the new condition to the old. */
2676 rcli = (struct reg_cond_life_info *) node->value;
2677 ncond = rcli->condition;
2678 ncond = ior_reg_cond (ncond, cond, 1);
2679 if (rcli->stores == const0_rtx)
2680 rcli->stores = cond;
2681 else if (rcli->stores != const1_rtx)
2682 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2684 /* If the register is now unconditionally dead, remove the entry
2685 in the splay_tree. A register is unconditionally dead if the
2686 dead condition ncond is true. A register is also unconditionally
2687 dead if the sum of all conditional stores is an unconditional
2688 store (stores is true), and the dead condition is identically the
2689 same as the original dead condition initialized at the end of
2690 the block. This is a pointer compare, not an rtx_equal_p
2692 if (ncond == const1_rtx
2693 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2694 splay_tree_remove (pbi->reg_cond_dead, regno);
2697 rcli->condition = ncond;
2699 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2701 /* Not unconditionaly dead. */
2710 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2713 free_reg_cond_life_info (value)
2714 splay_tree_value value;
2716 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2720 /* Helper function for flush_reg_cond_reg. */
2723 flush_reg_cond_reg_1 (node, data)
2724 splay_tree_node node;
2727 struct reg_cond_life_info *rcli;
2728 int *xdata = (int *) data;
2729 unsigned int regno = xdata[0];
2731 /* Don't need to search if last flushed value was farther on in
2732 the in-order traversal. */
2733 if (xdata[1] >= (int) node->key)
2736 /* Splice out portions of the expression that refer to regno. */
2737 rcli = (struct reg_cond_life_info *) node->value;
2738 rcli->condition = elim_reg_cond (rcli->condition, regno);
2739 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2740 rcli->stores = elim_reg_cond (rcli->stores, regno);
2742 /* If the entire condition is now false, signal the node to be removed. */
2743 if (rcli->condition == const0_rtx)
2745 xdata[1] = node->key;
2748 else if (rcli->condition == const1_rtx)
2754 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2757 flush_reg_cond_reg (pbi, regno)
2758 struct propagate_block_info *pbi;
2765 while (splay_tree_foreach (pbi->reg_cond_dead,
2766 flush_reg_cond_reg_1, pair) == -1)
2767 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2769 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2772 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2773 For ior/and, the ADD flag determines whether we want to add the new
2774 condition X to the old one unconditionally. If it is zero, we will
2775 only return a new expression if X allows us to simplify part of
2776 OLD, otherwise we return OLD unchanged to the caller.
2777 If ADD is nonzero, we will return a new condition in all cases. The
2778 toplevel caller of one of these functions should always pass 1 for
2782 ior_reg_cond (old, x, add)
2788 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2790 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2791 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2792 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2794 if (GET_CODE (x) == GET_CODE (old)
2795 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2799 return gen_rtx_IOR (0, old, x);
2802 switch (GET_CODE (old))
2805 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2806 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2807 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2809 if (op0 == const0_rtx)
2811 if (op1 == const0_rtx)
2813 if (op0 == const1_rtx || op1 == const1_rtx)
2815 if (op0 == XEXP (old, 0))
2816 op0 = gen_rtx_IOR (0, op0, x);
2818 op1 = gen_rtx_IOR (0, op1, x);
2819 return gen_rtx_IOR (0, op0, op1);
2823 return gen_rtx_IOR (0, old, x);
2826 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2827 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2828 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2830 if (op0 == const1_rtx)
2832 if (op1 == const1_rtx)
2834 if (op0 == const0_rtx || op1 == const0_rtx)
2836 if (op0 == XEXP (old, 0))
2837 op0 = gen_rtx_IOR (0, op0, x);
2839 op1 = gen_rtx_IOR (0, op1, x);
2840 return gen_rtx_AND (0, op0, op1);
2844 return gen_rtx_IOR (0, old, x);
2847 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2848 if (op0 != XEXP (old, 0))
2849 return not_reg_cond (op0);
2852 return gen_rtx_IOR (0, old, x);
2863 enum rtx_code x_code;
2865 if (x == const0_rtx)
2867 else if (x == const1_rtx)
2869 x_code = GET_CODE (x);
2872 if (GET_RTX_CLASS (x_code) == '<'
2873 && GET_CODE (XEXP (x, 0)) == REG)
2875 if (XEXP (x, 1) != const0_rtx)
2878 return gen_rtx_fmt_ee (reverse_condition (x_code),
2879 VOIDmode, XEXP (x, 0), const0_rtx);
2881 return gen_rtx_NOT (0, x);
2885 and_reg_cond (old, x, add)
2891 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2893 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2894 && GET_CODE (x) == reverse_condition (GET_CODE (old))
2895 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2897 if (GET_CODE (x) == GET_CODE (old)
2898 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2902 return gen_rtx_AND (0, old, x);
2905 switch (GET_CODE (old))
2908 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2909 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2910 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2912 if (op0 == const0_rtx)
2914 if (op1 == const0_rtx)
2916 if (op0 == const1_rtx || op1 == const1_rtx)
2918 if (op0 == XEXP (old, 0))
2919 op0 = gen_rtx_AND (0, op0, x);
2921 op1 = gen_rtx_AND (0, op1, x);
2922 return gen_rtx_IOR (0, op0, op1);
2926 return gen_rtx_AND (0, old, x);
2929 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2930 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2931 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2933 if (op0 == const1_rtx)
2935 if (op1 == const1_rtx)
2937 if (op0 == const0_rtx || op1 == const0_rtx)
2939 if (op0 == XEXP (old, 0))
2940 op0 = gen_rtx_AND (0, op0, x);
2942 op1 = gen_rtx_AND (0, op1, x);
2943 return gen_rtx_AND (0, op0, op1);
2948 /* If X is identical to one of the existing terms of the AND,
2949 then just return what we already have. */
2950 /* ??? There really should be some sort of recursive check here in
2951 case there are nested ANDs. */
2952 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
2953 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
2954 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
2955 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
2958 return gen_rtx_AND (0, old, x);
2961 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2962 if (op0 != XEXP (old, 0))
2963 return not_reg_cond (op0);
2966 return gen_rtx_AND (0, old, x);
2973 /* Given a condition X, remove references to reg REGNO and return the
2974 new condition. The removal will be done so that all conditions
2975 involving REGNO are considered to evaluate to false. This function
2976 is used when the value of REGNO changes. */
2979 elim_reg_cond (x, regno)
2985 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
2987 if (REGNO (XEXP (x, 0)) == regno)
2992 switch (GET_CODE (x))
2995 op0 = elim_reg_cond (XEXP (x, 0), regno);
2996 op1 = elim_reg_cond (XEXP (x, 1), regno);
2997 if (op0 == const0_rtx || op1 == const0_rtx)
2999 if (op0 == const1_rtx)
3001 if (op1 == const1_rtx)
3003 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3005 return gen_rtx_AND (0, op0, op1);
3008 op0 = elim_reg_cond (XEXP (x, 0), regno);
3009 op1 = elim_reg_cond (XEXP (x, 1), regno);
3010 if (op0 == const1_rtx || op1 == const1_rtx)
3012 if (op0 == const0_rtx)
3014 if (op1 == const0_rtx)
3016 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3018 return gen_rtx_IOR (0, op0, op1);
3021 op0 = elim_reg_cond (XEXP (x, 0), regno);
3022 if (op0 == const0_rtx)
3024 if (op0 == const1_rtx)
3026 if (op0 != XEXP (x, 0))
3027 return not_reg_cond (op0);
3034 #endif /* HAVE_conditional_execution */
3038 /* Try to substitute the auto-inc expression INC as the address inside
3039 MEM which occurs in INSN. Currently, the address of MEM is an expression
3040 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3041 that has a single set whose source is a PLUS of INCR_REG and something
3045 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3046 struct propagate_block_info *pbi;
3047 rtx inc, insn, mem, incr, incr_reg;
3049 int regno = REGNO (incr_reg);
3050 rtx set = single_set (incr);
3051 rtx q = SET_DEST (set);
3052 rtx y = SET_SRC (set);
3053 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3055 /* Make sure this reg appears only once in this insn. */
3056 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3059 if (dead_or_set_p (incr, incr_reg)
3060 /* Mustn't autoinc an eliminable register. */
3061 && (regno >= FIRST_PSEUDO_REGISTER
3062 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3064 /* This is the simple case. Try to make the auto-inc. If
3065 we can't, we are done. Otherwise, we will do any
3066 needed updates below. */
3067 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3070 else if (GET_CODE (q) == REG
3071 /* PREV_INSN used here to check the semi-open interval
3073 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3074 /* We must also check for sets of q as q may be
3075 a call clobbered hard register and there may
3076 be a call between PREV_INSN (insn) and incr. */
3077 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3079 /* We have *p followed sometime later by q = p+size.
3080 Both p and q must be live afterward,
3081 and q is not used between INSN and its assignment.
3082 Change it to q = p, ...*q..., q = q+size.
3083 Then fall into the usual case. */
3087 emit_move_insn (q, incr_reg);
3088 insns = get_insns ();
3091 /* If we can't make the auto-inc, or can't make the
3092 replacement into Y, exit. There's no point in making
3093 the change below if we can't do the auto-inc and doing
3094 so is not correct in the pre-inc case. */
3097 validate_change (insn, &XEXP (mem, 0), inc, 1);
3098 validate_change (incr, &XEXP (y, opnum), q, 1);
3099 if (! apply_change_group ())
3102 /* We now know we'll be doing this change, so emit the
3103 new insn(s) and do the updates. */
3104 emit_insns_before (insns, insn);
3106 if (pbi->bb->head == insn)
3107 pbi->bb->head = insns;
3109 /* INCR will become a NOTE and INSN won't contain a
3110 use of INCR_REG. If a use of INCR_REG was just placed in
3111 the insn before INSN, make that the next use.
3112 Otherwise, invalidate it. */
3113 if (GET_CODE (PREV_INSN (insn)) == INSN
3114 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3115 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3116 pbi->reg_next_use[regno] = PREV_INSN (insn);
3118 pbi->reg_next_use[regno] = 0;
3123 /* REGNO is now used in INCR which is below INSN, but
3124 it previously wasn't live here. If we don't mark
3125 it as live, we'll put a REG_DEAD note for it
3126 on this insn, which is incorrect. */
3127 SET_REGNO_REG_SET (pbi->reg_live, regno);
3129 /* If there are any calls between INSN and INCR, show
3130 that REGNO now crosses them. */
3131 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3132 if (GET_CODE (temp) == CALL_INSN)
3133 REG_N_CALLS_CROSSED (regno)++;
3135 /* Invalidate alias info for Q since we just changed its value. */
3136 clear_reg_alias_info (q);
3141 /* If we haven't returned, it means we were able to make the
3142 auto-inc, so update the status. First, record that this insn
3143 has an implicit side effect. */
3145 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3147 /* Modify the old increment-insn to simply copy
3148 the already-incremented value of our register. */
3149 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3152 /* If that makes it a no-op (copying the register into itself) delete
3153 it so it won't appear to be a "use" and a "set" of this
3155 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3157 /* If the original source was dead, it's dead now. */
3160 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3162 remove_note (incr, note);
3163 if (XEXP (note, 0) != incr_reg)
3164 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3167 PUT_CODE (incr, NOTE);
3168 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3169 NOTE_SOURCE_FILE (incr) = 0;
3172 if (regno >= FIRST_PSEUDO_REGISTER)
3174 /* Count an extra reference to the reg. When a reg is
3175 incremented, spilling it is worse, so we want to make
3176 that less likely. */
3177 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3179 /* Count the increment as a setting of the register,
3180 even though it isn't a SET in rtl. */
3181 REG_N_SETS (regno)++;
3185 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3189 find_auto_inc (pbi, x, insn)
3190 struct propagate_block_info *pbi;
3194 rtx addr = XEXP (x, 0);
3195 HOST_WIDE_INT offset = 0;
3196 rtx set, y, incr, inc_val;
3198 int size = GET_MODE_SIZE (GET_MODE (x));
3200 if (GET_CODE (insn) == JUMP_INSN)
3203 /* Here we detect use of an index register which might be good for
3204 postincrement, postdecrement, preincrement, or predecrement. */
3206 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3207 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3209 if (GET_CODE (addr) != REG)
3212 regno = REGNO (addr);
3214 /* Is the next use an increment that might make auto-increment? */
3215 incr = pbi->reg_next_use[regno];
3216 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3218 set = single_set (incr);
3219 if (set == 0 || GET_CODE (set) != SET)
3223 if (GET_CODE (y) != PLUS)
3226 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3227 inc_val = XEXP (y, 1);
3228 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3229 inc_val = XEXP (y, 0);
3233 if (GET_CODE (inc_val) == CONST_INT)
3235 if (HAVE_POST_INCREMENT
3236 && (INTVAL (inc_val) == size && offset == 0))
3237 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3239 else if (HAVE_POST_DECREMENT
3240 && (INTVAL (inc_val) == -size && offset == 0))
3241 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3243 else if (HAVE_PRE_INCREMENT
3244 && (INTVAL (inc_val) == size && offset == size))
3245 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3247 else if (HAVE_PRE_DECREMENT
3248 && (INTVAL (inc_val) == -size && offset == -size))
3249 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3251 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3252 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3253 gen_rtx_PLUS (Pmode,
3256 insn, x, incr, addr);
3258 else if (GET_CODE (inc_val) == REG
3259 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3263 if (HAVE_POST_MODIFY_REG && offset == 0)
3264 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3265 gen_rtx_PLUS (Pmode,
3268 insn, x, incr, addr);
3272 #endif /* AUTO_INC_DEC */
3275 mark_used_reg (pbi, reg, cond, insn)
3276 struct propagate_block_info *pbi;
3278 rtx cond ATTRIBUTE_UNUSED;
3281 unsigned int regno_first, regno_last, i;
3282 int some_was_live, some_was_dead, some_not_set;
3284 regno_last = regno_first = REGNO (reg);
3285 if (regno_first < FIRST_PSEUDO_REGISTER)
3286 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3288 /* Find out if any of this register is live after this instruction. */
3289 some_was_live = some_was_dead = 0;
3290 for (i = regno_first; i <= regno_last; ++i)
3292 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3293 some_was_live |= needed_regno;
3294 some_was_dead |= ! needed_regno;
3297 /* Find out if any of the register was set this insn. */
3299 for (i = regno_first; i <= regno_last; ++i)
3300 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3302 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3304 /* Record where each reg is used, so when the reg is set we know
3305 the next insn that uses it. */
3306 pbi->reg_next_use[regno_first] = insn;
3309 if (pbi->flags & PROP_REG_INFO)
3311 if (regno_first < FIRST_PSEUDO_REGISTER)
3313 /* If this is a register we are going to try to eliminate,
3314 don't mark it live here. If we are successful in
3315 eliminating it, it need not be live unless it is used for
3316 pseudos, in which case it will have been set live when it
3317 was allocated to the pseudos. If the register will not
3318 be eliminated, reload will set it live at that point.
3320 Otherwise, record that this function uses this register. */
3321 /* ??? The PPC backend tries to "eliminate" on the pic
3322 register to itself. This should be fixed. In the mean
3323 time, hack around it. */
3325 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3326 && (regno_first == FRAME_POINTER_REGNUM
3327 || regno_first == ARG_POINTER_REGNUM)))
3328 for (i = regno_first; i <= regno_last; ++i)
3329 regs_ever_live[i] = 1;
3333 /* Keep track of which basic block each reg appears in. */
3335 register int blocknum = pbi->bb->index;
3336 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3337 REG_BASIC_BLOCK (regno_first) = blocknum;
3338 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3339 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3341 /* Count (weighted) number of uses of each reg. */
3342 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3343 REG_N_REFS (regno_first)++;
3347 /* Record and count the insns in which a reg dies. If it is used in
3348 this insn and was dead below the insn then it dies in this insn.
3349 If it was set in this insn, we do not make a REG_DEAD note;
3350 likewise if we already made such a note. */
3351 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3355 /* Check for the case where the register dying partially
3356 overlaps the register set by this insn. */
3357 if (regno_first != regno_last)
3358 for (i = regno_first; i <= regno_last; ++i)
3359 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3361 /* If none of the words in X is needed, make a REG_DEAD note.
3362 Otherwise, we must make partial REG_DEAD notes. */
3363 if (! some_was_live)
3365 if ((pbi->flags & PROP_DEATH_NOTES)
3366 && ! find_regno_note (insn, REG_DEAD, regno_first))
3368 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3370 if (pbi->flags & PROP_REG_INFO)
3371 REG_N_DEATHS (regno_first)++;
3375 /* Don't make a REG_DEAD note for a part of a register
3376 that is set in the insn. */
3377 for (i = regno_first; i <= regno_last; ++i)
3378 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3379 && ! dead_or_set_regno_p (insn, i))
3381 = alloc_EXPR_LIST (REG_DEAD,
3382 gen_rtx_REG (reg_raw_mode[i], i),
3387 /* Mark the register as being live. */
3388 for (i = regno_first; i <= regno_last; ++i)
3390 SET_REGNO_REG_SET (pbi->reg_live, i);
3392 #ifdef HAVE_conditional_execution
3393 /* If this is a conditional use, record that fact. If it is later
3394 conditionally set, we'll know to kill the register. */
3395 if (cond != NULL_RTX)
3397 splay_tree_node node;
3398 struct reg_cond_life_info *rcli;
3403 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3406 /* The register was unconditionally live previously.
3407 No need to do anything. */
3411 /* The register was conditionally live previously.
3412 Subtract the new life cond from the old death cond. */
3413 rcli = (struct reg_cond_life_info *) node->value;
3414 ncond = rcli->condition;
3415 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3417 /* If the register is now unconditionally live,
3418 remove the entry in the splay_tree. */
3419 if (ncond == const0_rtx)
3420 splay_tree_remove (pbi->reg_cond_dead, i);
3423 rcli->condition = ncond;
3424 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3425 REGNO (XEXP (cond, 0)));
3431 /* The register was not previously live at all. Record
3432 the condition under which it is still dead. */
3433 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3434 rcli->condition = not_reg_cond (cond);
3435 rcli->stores = const0_rtx;
3436 rcli->orig_condition = const0_rtx;
3437 splay_tree_insert (pbi->reg_cond_dead, i,
3438 (splay_tree_value) rcli);
3440 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3443 else if (some_was_live)
3445 /* The register may have been conditionally live previously, but
3446 is now unconditionally live. Remove it from the conditionally
3447 dead list, so that a conditional set won't cause us to think
3449 splay_tree_remove (pbi->reg_cond_dead, i);
3455 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3456 This is done assuming the registers needed from X are those that
3457 have 1-bits in PBI->REG_LIVE.
3459 INSN is the containing instruction. If INSN is dead, this function
3463 mark_used_regs (pbi, x, cond, insn)
3464 struct propagate_block_info *pbi;
3467 register RTX_CODE code;
3469 int flags = pbi->flags;
3472 code = GET_CODE (x);
3492 /* If we are clobbering a MEM, mark any registers inside the address
3494 if (GET_CODE (XEXP (x, 0)) == MEM)
3495 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3499 /* Don't bother watching stores to mems if this is not the
3500 final pass. We'll not be deleting dead stores this round. */
3501 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3503 /* Invalidate the data for the last MEM stored, but only if MEM is
3504 something that can be stored into. */
3505 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3506 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3507 /* Needn't clear the memory set list. */
3511 rtx temp = pbi->mem_set_list;
3512 rtx prev = NULL_RTX;
3517 next = XEXP (temp, 1);
3518 if (anti_dependence (XEXP (temp, 0), x))
3520 /* Splice temp out of the list. */
3522 XEXP (prev, 1) = next;
3524 pbi->mem_set_list = next;
3525 free_EXPR_LIST_node (temp);
3526 pbi->mem_set_list_len--;
3534 /* If the memory reference had embedded side effects (autoincrement
3535 address modes. Then we may need to kill some entries on the
3538 invalidate_mems_from_autoinc (pbi, insn);
3542 if (flags & PROP_AUTOINC)
3543 find_auto_inc (pbi, x, insn);
3548 #ifdef CLASS_CANNOT_CHANGE_MODE
3549 if (GET_CODE (SUBREG_REG (x)) == REG
3550 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3551 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3552 GET_MODE (SUBREG_REG (x))))
3553 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3556 /* While we're here, optimize this case. */
3558 if (GET_CODE (x) != REG)
3563 /* See a register other than being set => mark it as needed. */
3564 mark_used_reg (pbi, x, cond, insn);
3569 register rtx testreg = SET_DEST (x);
3572 /* If storing into MEM, don't show it as being used. But do
3573 show the address as being used. */
3574 if (GET_CODE (testreg) == MEM)
3577 if (flags & PROP_AUTOINC)
3578 find_auto_inc (pbi, testreg, insn);
3580 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3581 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3585 /* Storing in STRICT_LOW_PART is like storing in a reg
3586 in that this SET might be dead, so ignore it in TESTREG.
3587 but in some other ways it is like using the reg.
3589 Storing in a SUBREG or a bit field is like storing the entire
3590 register in that if the register's value is not used
3591 then this SET is not needed. */
3592 while (GET_CODE (testreg) == STRICT_LOW_PART
3593 || GET_CODE (testreg) == ZERO_EXTRACT
3594 || GET_CODE (testreg) == SIGN_EXTRACT
3595 || GET_CODE (testreg) == SUBREG)
3597 #ifdef CLASS_CANNOT_CHANGE_MODE
3598 if (GET_CODE (testreg) == SUBREG
3599 && GET_CODE (SUBREG_REG (testreg)) == REG
3600 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3601 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3602 GET_MODE (testreg)))
3603 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3606 /* Modifying a single register in an alternate mode
3607 does not use any of the old value. But these other
3608 ways of storing in a register do use the old value. */
3609 if (GET_CODE (testreg) == SUBREG
3610 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
3615 testreg = XEXP (testreg, 0);
3618 /* If this is a store into a register or group of registers,
3619 recursively scan the value being stored. */
3621 if ((GET_CODE (testreg) == PARALLEL
3622 && GET_MODE (testreg) == BLKmode)
3623 || (GET_CODE (testreg) == REG
3624 && (regno = REGNO (testreg),
3625 ! (regno == FRAME_POINTER_REGNUM
3626 && (! reload_completed || frame_pointer_needed)))
3627 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3628 && ! (regno == HARD_FRAME_POINTER_REGNUM
3629 && (! reload_completed || frame_pointer_needed))
3631 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3632 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3637 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3638 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3645 case UNSPEC_VOLATILE:
3649 /* Traditional and volatile asm instructions must be considered to use
3650 and clobber all hard registers, all pseudo-registers and all of
3651 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3653 Consider for instance a volatile asm that changes the fpu rounding
3654 mode. An insn should not be moved across this even if it only uses
3655 pseudo-regs because it might give an incorrectly rounded result.
3657 ?!? Unfortunately, marking all hard registers as live causes massive
3658 problems for the register allocator and marking all pseudos as live
3659 creates mountains of uninitialized variable warnings.
3661 So for now, just clear the memory set list and mark any regs
3662 we can find in ASM_OPERANDS as used. */
3663 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3665 free_EXPR_LIST_list (&pbi->mem_set_list);
3666 pbi->mem_set_list_len = 0;
3669 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3670 We can not just fall through here since then we would be confused
3671 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3672 traditional asms unlike their normal usage. */
3673 if (code == ASM_OPERANDS)
3677 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3678 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3684 if (cond != NULL_RTX)
3687 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3689 cond = COND_EXEC_TEST (x);
3690 x = COND_EXEC_CODE (x);
3694 /* We _do_not_ want to scan operands of phi nodes. Operands of
3695 a phi function are evaluated only when control reaches this
3696 block along a particular edge. Therefore, regs that appear
3697 as arguments to phi should not be added to the global live at
3705 /* Recursively scan the operands of this expression. */
3708 register const char * const fmt = GET_RTX_FORMAT (code);
3711 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3715 /* Tail recursive case: save a function call level. */
3721 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3723 else if (fmt[i] == 'E')
3726 for (j = 0; j < XVECLEN (x, i); j++)
3727 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3736 try_pre_increment_1 (pbi, insn)
3737 struct propagate_block_info *pbi;
3740 /* Find the next use of this reg. If in same basic block,
3741 make it do pre-increment or pre-decrement if appropriate. */
3742 rtx x = single_set (insn);
3743 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3744 * INTVAL (XEXP (SET_SRC (x), 1)));
3745 int regno = REGNO (SET_DEST (x));
3746 rtx y = pbi->reg_next_use[regno];
3748 && SET_DEST (x) != stack_pointer_rtx
3749 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3750 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3751 mode would be better. */
3752 && ! dead_or_set_p (y, SET_DEST (x))
3753 && try_pre_increment (y, SET_DEST (x), amount))
3755 /* We have found a suitable auto-increment and already changed
3756 insn Y to do it. So flush this increment instruction. */
3757 propagate_block_delete_insn (pbi->bb, insn);
3759 /* Count a reference to this reg for the increment insn we are
3760 deleting. When a reg is incremented, spilling it is worse,
3761 so we want to make that less likely. */
3762 if (regno >= FIRST_PSEUDO_REGISTER)
3764 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3765 REG_N_SETS (regno)++;
3768 /* Flush any remembered memories depending on the value of
3769 the incremented register. */
3770 invalidate_mems_from_set (pbi, SET_DEST (x));
3777 /* Try to change INSN so that it does pre-increment or pre-decrement
3778 addressing on register REG in order to add AMOUNT to REG.
3779 AMOUNT is negative for pre-decrement.
3780 Returns 1 if the change could be made.
3781 This checks all about the validity of the result of modifying INSN. */
3784 try_pre_increment (insn, reg, amount)
3786 HOST_WIDE_INT amount;
3790 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3791 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3793 /* Nonzero if we can try to make a post-increment or post-decrement.
3794 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3795 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3796 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3799 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3802 /* From the sign of increment, see which possibilities are conceivable
3803 on this target machine. */
3804 if (HAVE_PRE_INCREMENT && amount > 0)
3806 if (HAVE_POST_INCREMENT && amount > 0)
3809 if (HAVE_PRE_DECREMENT && amount < 0)
3811 if (HAVE_POST_DECREMENT && amount < 0)
3814 if (! (pre_ok || post_ok))
3817 /* It is not safe to add a side effect to a jump insn
3818 because if the incremented register is spilled and must be reloaded
3819 there would be no way to store the incremented value back in memory. */
3821 if (GET_CODE (insn) == JUMP_INSN)
3826 use = find_use_as_address (PATTERN (insn), reg, 0);
3827 if (post_ok && (use == 0 || use == (rtx) 1))
3829 use = find_use_as_address (PATTERN (insn), reg, -amount);
3833 if (use == 0 || use == (rtx) 1)
3836 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
3839 /* See if this combination of instruction and addressing mode exists. */
3840 if (! validate_change (insn, &XEXP (use, 0),
3841 gen_rtx_fmt_e (amount > 0
3842 ? (do_post ? POST_INC : PRE_INC)
3843 : (do_post ? POST_DEC : PRE_DEC),
3847 /* Record that this insn now has an implicit side effect on X. */
3848 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
3852 #endif /* AUTO_INC_DEC */
3854 /* Find the place in the rtx X where REG is used as a memory address.
3855 Return the MEM rtx that so uses it.
3856 If PLUSCONST is nonzero, search instead for a memory address equivalent to
3857 (plus REG (const_int PLUSCONST)).
3859 If such an address does not appear, return 0.
3860 If REG appears more than once, or is used other than in such an address,
3864 find_use_as_address (x, reg, plusconst)
3867 HOST_WIDE_INT plusconst;
3869 enum rtx_code code = GET_CODE (x);
3870 const char * const fmt = GET_RTX_FORMAT (code);
3872 register rtx value = 0;
3875 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
3878 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
3879 && XEXP (XEXP (x, 0), 0) == reg
3880 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
3881 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
3884 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
3886 /* If REG occurs inside a MEM used in a bit-field reference,
3887 that is unacceptable. */
3888 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
3889 return (rtx) (HOST_WIDE_INT) 1;
3893 return (rtx) (HOST_WIDE_INT) 1;
3895 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3899 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
3903 return (rtx) (HOST_WIDE_INT) 1;
3905 else if (fmt[i] == 'E')
3908 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3910 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
3914 return (rtx) (HOST_WIDE_INT) 1;
3922 /* Write information about registers and basic blocks into FILE.
3923 This is part of making a debugging dump. */
3926 dump_regset (r, outf)
3933 fputs (" (nil)", outf);
3937 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
3939 fprintf (outf, " %d", i);
3940 if (i < FIRST_PSEUDO_REGISTER)
3941 fprintf (outf, " [%s]",
3946 /* Print a human-reaable representation of R on the standard error
3947 stream. This function is designed to be used from within the
3954 dump_regset (r, stderr);
3955 putc ('\n', stderr);
3958 /* Dump the rtl into the current debugging dump file, then abort. */
3961 print_rtl_and_abort_fcn (file, line, function)
3964 const char *function;
3968 print_rtl_with_bb (rtl_dump_file, get_insns ());
3969 fclose (rtl_dump_file);
3972 fancy_abort (file, line, function);
3975 /* Recompute register set/reference counts immediately prior to register
3978 This avoids problems with set/reference counts changing to/from values
3979 which have special meanings to the register allocators.
3981 Additionally, the reference counts are the primary component used by the
3982 register allocators to prioritize pseudos for allocation to hard regs.
3983 More accurate reference counts generally lead to better register allocation.
3985 F is the first insn to be scanned.
3987 LOOP_STEP denotes how much loop_depth should be incremented per
3988 loop nesting level in order to increase the ref count more for
3989 references in a loop.
3991 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
3992 possibly other information which is used by the register allocators. */
3995 recompute_reg_usage (f, loop_step)
3996 rtx f ATTRIBUTE_UNUSED;
3997 int loop_step ATTRIBUTE_UNUSED;
3999 allocate_reg_life_data ();
4000 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4003 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4004 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4005 of the number of registers that died. */
4008 count_or_remove_death_notes (blocks, kill)
4014 for (i = n_basic_blocks - 1; i >= 0; --i)
4019 if (blocks && ! TEST_BIT (blocks, i))
4022 bb = BASIC_BLOCK (i);
4024 for (insn = bb->head;; insn = NEXT_INSN (insn))
4028 rtx *pprev = ®_NOTES (insn);
4033 switch (REG_NOTE_KIND (link))
4036 if (GET_CODE (XEXP (link, 0)) == REG)
4038 rtx reg = XEXP (link, 0);
4041 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4044 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4052 rtx next = XEXP (link, 1);
4053 free_EXPR_LIST_node (link);
4054 *pprev = link = next;
4060 pprev = &XEXP (link, 1);
4067 if (insn == bb->end)
4074 /* Clear LOG_LINKS fields of insns in a chain.
4075 Also clear the global_live_at_{start,end} fields of the basic block
4079 clear_log_links (insns)
4085 for (i = insns; i; i = NEXT_INSN (i))
4089 for (b = 0; b < n_basic_blocks; b++)
4091 basic_block bb = BASIC_BLOCK (b);
4093 bb->global_live_at_start = NULL;
4094 bb->global_live_at_end = NULL;
4097 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
4098 EXIT_BLOCK_PTR->global_live_at_start = NULL;
4101 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4102 correspond to the hard registers, if any, set in that map. This
4103 could be done far more efficiently by having all sorts of special-cases
4104 with moving single words, but probably isn't worth the trouble. */
4107 reg_set_to_hard_reg_set (to, from)
4113 EXECUTE_IF_SET_IN_BITMAP
4116 if (i >= FIRST_PSEUDO_REGISTER)
4118 SET_HARD_REG_BIT (*to, i);