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 compute_bb_for_insn (max_uid);
382 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
383 warning ("control reaches end of non-void function");
388 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
389 note associated with the BLOCK. */
392 first_insn_after_basic_block_note (block)
397 /* Get the first instruction in the block. */
400 if (insn == NULL_RTX)
402 if (GET_CODE (insn) == CODE_LABEL)
403 insn = NEXT_INSN (insn);
404 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
407 return NEXT_INSN (insn);
410 /* Perform data flow analysis.
411 F is the first insn of the function; FLAGS is a set of PROP_* flags
412 to be used in accumulating flow info. */
415 life_analysis (f, file, flags)
420 #ifdef ELIMINABLE_REGS
422 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
425 /* Record which registers will be eliminated. We use this in
428 CLEAR_HARD_REG_SET (elim_reg_set);
430 #ifdef ELIMINABLE_REGS
431 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
432 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
434 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
438 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
440 /* The post-reload life analysis have (on a global basis) the same
441 registers live as was computed by reload itself. elimination
442 Otherwise offsets and such may be incorrect.
444 Reload will make some registers as live even though they do not
447 We don't want to create new auto-incs after reload, since they
448 are unlikely to be useful and can cause problems with shared
450 if (reload_completed)
451 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
453 /* We want alias analysis information for local dead store elimination. */
454 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
455 init_alias_analysis ();
457 /* Always remove no-op moves. Do this before other processing so
458 that we don't have to keep re-scanning them. */
459 delete_noop_moves (f);
461 /* Some targets can emit simpler epilogues if they know that sp was
462 not ever modified during the function. After reload, of course,
463 we've already emitted the epilogue so there's no sense searching. */
464 if (! reload_completed)
465 notice_stack_pointer_modification (f);
467 /* Allocate and zero out data structures that will record the
468 data from lifetime analysis. */
469 allocate_reg_life_data ();
470 allocate_bb_life_data ();
472 /* Find the set of registers live on function exit. */
473 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
475 /* "Update" life info from zero. It'd be nice to begin the
476 relaxation with just the exit and noreturn blocks, but that set
477 is not immediately handy. */
479 if (flags & PROP_REG_INFO)
480 memset (regs_ever_live, 0, sizeof (regs_ever_live));
481 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
484 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
485 end_alias_analysis ();
488 dump_flow_info (file);
490 free_basic_block_vars (1);
492 #ifdef ENABLE_CHECKING
496 /* Search for any REG_LABEL notes which reference deleted labels. */
497 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
499 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
501 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
506 /* Removing dead insns should've made jumptables really dead. */
507 delete_dead_jumptables ();
510 /* A subroutine of verify_wide_reg, called through for_each_rtx.
511 Search for REGNO. If found, abort if it is not wider than word_mode. */
514 verify_wide_reg_1 (px, pregno)
519 unsigned int regno = *(int *) pregno;
521 if (GET_CODE (x) == REG && REGNO (x) == regno)
523 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
530 /* A subroutine of verify_local_live_at_start. Search through insns
531 between HEAD and END looking for register REGNO. */
534 verify_wide_reg (regno, head, end)
541 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
545 head = NEXT_INSN (head);
548 /* We didn't find the register at all. Something's way screwy. */
550 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
551 print_rtl_and_abort ();
554 /* A subroutine of update_life_info. Verify that there are no untoward
555 changes in live_at_start during a local update. */
558 verify_local_live_at_start (new_live_at_start, bb)
559 regset new_live_at_start;
562 if (reload_completed)
564 /* After reload, there are no pseudos, nor subregs of multi-word
565 registers. The regsets should exactly match. */
566 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
570 fprintf (rtl_dump_file,
571 "live_at_start mismatch in bb %d, aborting\n",
573 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
574 debug_bitmap_file (rtl_dump_file, new_live_at_start);
576 print_rtl_and_abort ();
583 /* Find the set of changed registers. */
584 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
586 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
588 /* No registers should die. */
589 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
592 fprintf (rtl_dump_file,
593 "Register %d died unexpectedly in block %d\n", i,
595 print_rtl_and_abort ();
598 /* Verify that the now-live register is wider than word_mode. */
599 verify_wide_reg (i, bb->head, bb->end);
604 /* Updates life information starting with the basic blocks set in BLOCKS.
605 If BLOCKS is null, consider it to be the universal set.
607 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
608 we are only expecting local modifications to basic blocks. If we find
609 extra registers live at the beginning of a block, then we either killed
610 useful data, or we have a broken split that wants data not provided.
611 If we find registers removed from live_at_start, that means we have
612 a broken peephole that is killing a register it shouldn't.
614 ??? This is not true in one situation -- when a pre-reload splitter
615 generates subregs of a multi-word pseudo, current life analysis will
616 lose the kill. So we _can_ have a pseudo go live. How irritating.
618 Including PROP_REG_INFO does not properly refresh regs_ever_live
619 unless the caller resets it to zero. */
622 update_life_info (blocks, extent, prop_flags)
624 enum update_life_extent extent;
628 regset_head tmp_head;
631 tmp = INITIALIZE_REG_SET (tmp_head);
633 /* Changes to the CFG are only allowed when
634 doing a global update for the entire CFG. */
635 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
636 && (extent == UPDATE_LIFE_LOCAL || blocks))
639 /* For a global update, we go through the relaxation process again. */
640 if (extent != UPDATE_LIFE_LOCAL)
646 calculate_global_regs_live (blocks, blocks,
647 prop_flags & (PROP_SCAN_DEAD_CODE
648 | PROP_ALLOW_CFG_CHANGES));
650 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
651 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
654 /* Removing dead code may allow the CFG to be simplified which
655 in turn may allow for further dead code detection / removal. */
656 for (i = n_basic_blocks - 1; i >= 0; --i)
658 basic_block bb = BASIC_BLOCK (i);
660 COPY_REG_SET (tmp, bb->global_live_at_end);
661 changed |= propagate_block (bb, tmp, NULL, NULL,
662 prop_flags & (PROP_SCAN_DEAD_CODE
663 | PROP_KILL_DEAD_CODE));
666 if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE))
670 /* If asked, remove notes from the blocks we'll update. */
671 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
672 count_or_remove_death_notes (blocks, 1);
677 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
679 basic_block bb = BASIC_BLOCK (i);
681 COPY_REG_SET (tmp, bb->global_live_at_end);
682 propagate_block (bb, tmp, NULL, NULL, prop_flags);
684 if (extent == UPDATE_LIFE_LOCAL)
685 verify_local_live_at_start (tmp, bb);
690 for (i = n_basic_blocks - 1; i >= 0; --i)
692 basic_block bb = BASIC_BLOCK (i);
694 COPY_REG_SET (tmp, bb->global_live_at_end);
695 propagate_block (bb, tmp, NULL, NULL, prop_flags);
697 if (extent == UPDATE_LIFE_LOCAL)
698 verify_local_live_at_start (tmp, bb);
704 if (prop_flags & PROP_REG_INFO)
706 /* The only pseudos that are live at the beginning of the function
707 are those that were not set anywhere in the function. local-alloc
708 doesn't know how to handle these correctly, so mark them as not
709 local to any one basic block. */
710 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
711 FIRST_PSEUDO_REGISTER, i,
712 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
714 /* We have a problem with any pseudoreg that lives across the setjmp.
715 ANSI says that if a user variable does not change in value between
716 the setjmp and the longjmp, then the longjmp preserves it. This
717 includes longjmp from a place where the pseudo appears dead.
718 (In principle, the value still exists if it is in scope.)
719 If the pseudo goes in a hard reg, some other value may occupy
720 that hard reg where this pseudo is dead, thus clobbering the pseudo.
721 Conclusion: such a pseudo must not go in a hard reg. */
722 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
723 FIRST_PSEUDO_REGISTER, i,
725 if (regno_reg_rtx[i] != 0)
727 REG_LIVE_LENGTH (i) = -1;
728 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
734 /* Free the variables allocated by find_basic_blocks.
736 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
739 free_basic_block_vars (keep_head_end_p)
742 if (basic_block_for_insn)
744 VARRAY_FREE (basic_block_for_insn);
745 basic_block_for_insn = NULL;
748 if (! keep_head_end_p)
750 if (basic_block_info)
753 VARRAY_FREE (basic_block_info);
757 ENTRY_BLOCK_PTR->aux = NULL;
758 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
759 EXIT_BLOCK_PTR->aux = NULL;
760 EXIT_BLOCK_PTR->global_live_at_start = NULL;
764 /* Delete any insns that copy a register to itself. */
767 delete_noop_moves (f)
768 rtx f ATTRIBUTE_UNUSED;
774 for (i = 0; i < n_basic_blocks; i++)
776 bb = BASIC_BLOCK (i);
777 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
779 next = NEXT_INSN (insn);
780 if (INSN_P (insn) && noop_move_p (insn))
782 /* Do not call flow_delete_insn here to not confuse backward
783 pointers of LIBCALL block. */
784 PUT_CODE (insn, NOTE);
785 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
786 NOTE_SOURCE_FILE (insn) = 0;
788 purge_dead_edges (bb);
794 /* Delete any jump tables never referenced. We can't delete them at the
795 time of removing tablejump insn as they are referenced by the preceeding
796 insns computing the destination, so we delay deleting and garbagecollect
797 them once life information is computed. */
799 delete_dead_jumptables ()
802 for (insn = get_insns (); insn; insn = next)
804 next = NEXT_INSN (insn);
805 if (GET_CODE (insn) == CODE_LABEL
806 && LABEL_NUSES (insn) == 0
807 && GET_CODE (next) == JUMP_INSN
808 && (GET_CODE (PATTERN (next)) == ADDR_VEC
809 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
812 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
813 flow_delete_insn (NEXT_INSN (insn));
814 flow_delete_insn (insn);
815 next = NEXT_INSN (next);
820 /* Determine if the stack pointer is constant over the life of the function.
821 Only useful before prologues have been emitted. */
824 notice_stack_pointer_modification_1 (x, pat, data)
826 rtx pat ATTRIBUTE_UNUSED;
827 void *data ATTRIBUTE_UNUSED;
829 if (x == stack_pointer_rtx
830 /* The stack pointer is only modified indirectly as the result
831 of a push until later in flow. See the comments in rtl.texi
832 regarding Embedded Side-Effects on Addresses. */
833 || (GET_CODE (x) == MEM
834 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
835 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
836 current_function_sp_is_unchanging = 0;
840 notice_stack_pointer_modification (f)
845 /* Assume that the stack pointer is unchanging if alloca hasn't
847 current_function_sp_is_unchanging = !current_function_calls_alloca;
848 if (! current_function_sp_is_unchanging)
851 for (insn = f; insn; insn = NEXT_INSN (insn))
855 /* Check if insn modifies the stack pointer. */
856 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
858 if (! current_function_sp_is_unchanging)
864 /* Mark a register in SET. Hard registers in large modes get all
865 of their component registers set as well. */
872 regset set = (regset) xset;
873 int regno = REGNO (reg);
875 if (GET_MODE (reg) == BLKmode)
878 SET_REGNO_REG_SET (set, regno);
879 if (regno < FIRST_PSEUDO_REGISTER)
881 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
883 SET_REGNO_REG_SET (set, regno + n);
887 /* Mark those regs which are needed at the end of the function as live
888 at the end of the last basic block. */
891 mark_regs_live_at_end (set)
896 /* If exiting needs the right stack value, consider the stack pointer
897 live at the end of the function. */
898 if ((HAVE_epilogue && reload_completed)
899 || ! EXIT_IGNORE_STACK
900 || (! FRAME_POINTER_REQUIRED
901 && ! current_function_calls_alloca
902 && flag_omit_frame_pointer)
903 || current_function_sp_is_unchanging)
905 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
908 /* Mark the frame pointer if needed at the end of the function. If
909 we end up eliminating it, it will be removed from the live list
910 of each basic block by reload. */
912 if (! reload_completed || frame_pointer_needed)
914 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
915 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
916 /* If they are different, also mark the hard frame pointer as live. */
917 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
918 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
922 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
923 /* Many architectures have a GP register even without flag_pic.
924 Assume the pic register is not in use, or will be handled by
925 other means, if it is not fixed. */
926 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
927 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
928 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
931 /* Mark all global registers, and all registers used by the epilogue
932 as being live at the end of the function since they may be
933 referenced by our caller. */
934 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
935 if (global_regs[i] || EPILOGUE_USES (i))
936 SET_REGNO_REG_SET (set, i);
938 if (HAVE_epilogue && reload_completed)
940 /* Mark all call-saved registers that we actually used. */
941 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
942 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
943 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
944 SET_REGNO_REG_SET (set, i);
947 #ifdef EH_RETURN_DATA_REGNO
948 /* Mark the registers that will contain data for the handler. */
949 if (reload_completed && current_function_calls_eh_return)
952 unsigned regno = EH_RETURN_DATA_REGNO(i);
953 if (regno == INVALID_REGNUM)
955 SET_REGNO_REG_SET (set, regno);
958 #ifdef EH_RETURN_STACKADJ_RTX
959 if ((! HAVE_epilogue || ! reload_completed)
960 && current_function_calls_eh_return)
962 rtx tmp = EH_RETURN_STACKADJ_RTX;
963 if (tmp && REG_P (tmp))
967 #ifdef EH_RETURN_HANDLER_RTX
968 if ((! HAVE_epilogue || ! reload_completed)
969 && current_function_calls_eh_return)
971 rtx tmp = EH_RETURN_HANDLER_RTX;
972 if (tmp && REG_P (tmp))
977 /* Mark function return value. */
978 diddle_return_value (mark_reg, set);
981 /* Callback function for for_each_successor_phi. DATA is a regset.
982 Sets the SRC_REGNO, the regno of the phi alternative for phi node
983 INSN, in the regset. */
986 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
987 rtx insn ATTRIBUTE_UNUSED;
988 int dest_regno ATTRIBUTE_UNUSED;
992 regset live = (regset) data;
993 SET_REGNO_REG_SET (live, src_regno);
997 /* Propagate global life info around the graph of basic blocks. Begin
998 considering blocks with their corresponding bit set in BLOCKS_IN.
999 If BLOCKS_IN is null, consider it the universal set.
1001 BLOCKS_OUT is set for every block that was changed. */
1004 calculate_global_regs_live (blocks_in, blocks_out, flags)
1005 sbitmap blocks_in, blocks_out;
1008 basic_block *queue, *qhead, *qtail, *qend;
1009 regset tmp, new_live_at_end, call_used;
1010 regset_head tmp_head, call_used_head;
1011 regset_head new_live_at_end_head;
1014 tmp = INITIALIZE_REG_SET (tmp_head);
1015 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1016 call_used = INITIALIZE_REG_SET (call_used_head);
1018 /* Inconveniently, this is only redily available in hard reg set form. */
1019 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1020 if (call_used_regs[i])
1021 SET_REGNO_REG_SET (call_used, i);
1023 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1024 because the `head == tail' style test for an empty queue doesn't
1025 work with a full queue. */
1026 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1028 qhead = qend = queue + n_basic_blocks + 2;
1030 /* Queue the blocks set in the initial mask. Do this in reverse block
1031 number order so that we are more likely for the first round to do
1032 useful work. We use AUX non-null to flag that the block is queued. */
1035 /* Clear out the garbage that might be hanging out in bb->aux. */
1036 for (i = n_basic_blocks - 1; i >= 0; --i)
1037 BASIC_BLOCK (i)->aux = NULL;
1039 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
1041 basic_block bb = BASIC_BLOCK (i);
1048 for (i = 0; i < n_basic_blocks; ++i)
1050 basic_block bb = BASIC_BLOCK (i);
1057 sbitmap_zero (blocks_out);
1059 /* We work through the queue until there are no more blocks. What
1060 is live at the end of this block is precisely the union of what
1061 is live at the beginning of all its successors. So, we set its
1062 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1063 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1064 this block by walking through the instructions in this block in
1065 reverse order and updating as we go. If that changed
1066 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1067 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1069 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1070 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1071 must either be live at the end of the block, or used within the
1072 block. In the latter case, it will certainly never disappear
1073 from GLOBAL_LIVE_AT_START. In the former case, the register
1074 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1075 for one of the successor blocks. By induction, that cannot
1077 while (qhead != qtail)
1079 int rescan, changed;
1088 /* Begin by propagating live_at_start from the successor blocks. */
1089 CLEAR_REG_SET (new_live_at_end);
1090 for (e = bb->succ; e; e = e->succ_next)
1092 basic_block sb = e->dest;
1094 /* Call-clobbered registers die across exception and call edges. */
1095 /* ??? Abnormal call edges ignored for the moment, as this gets
1096 confused by sibling call edges, which crashes reg-stack. */
1097 if (e->flags & EDGE_EH)
1099 bitmap_operation (tmp, sb->global_live_at_start,
1100 call_used, BITMAP_AND_COMPL);
1101 IOR_REG_SET (new_live_at_end, tmp);
1104 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1107 /* The all-important stack pointer must always be live. */
1108 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1110 /* Before reload, there are a few registers that must be forced
1111 live everywhere -- which might not already be the case for
1112 blocks within infinite loops. */
1113 if (! reload_completed)
1115 /* Any reference to any pseudo before reload is a potential
1116 reference of the frame pointer. */
1117 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1119 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1120 /* Pseudos with argument area equivalences may require
1121 reloading via the argument pointer. */
1122 if (fixed_regs[ARG_POINTER_REGNUM])
1123 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1126 /* Any constant, or pseudo with constant equivalences, may
1127 require reloading from memory using the pic register. */
1128 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1129 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1130 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1133 /* Regs used in phi nodes are not included in
1134 global_live_at_start, since they are live only along a
1135 particular edge. Set those regs that are live because of a
1136 phi node alternative corresponding to this particular block. */
1138 for_each_successor_phi (bb, &set_phi_alternative_reg,
1141 if (bb == ENTRY_BLOCK_PTR)
1143 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1147 /* On our first pass through this block, we'll go ahead and continue.
1148 Recognize first pass by local_set NULL. On subsequent passes, we
1149 get to skip out early if live_at_end wouldn't have changed. */
1151 if (bb->local_set == NULL)
1153 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1154 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1159 /* If any bits were removed from live_at_end, we'll have to
1160 rescan the block. This wouldn't be necessary if we had
1161 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1162 local_live is really dependent on live_at_end. */
1163 CLEAR_REG_SET (tmp);
1164 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1165 new_live_at_end, BITMAP_AND_COMPL);
1169 /* If any of the registers in the new live_at_end set are
1170 conditionally set in this basic block, we must rescan.
1171 This is because conditional lifetimes at the end of the
1172 block do not just take the live_at_end set into account,
1173 but also the liveness at the start of each successor
1174 block. We can miss changes in those sets if we only
1175 compare the new live_at_end against the previous one. */
1176 CLEAR_REG_SET (tmp);
1177 rescan = bitmap_operation (tmp, new_live_at_end,
1178 bb->cond_local_set, BITMAP_AND);
1183 /* Find the set of changed bits. Take this opportunity
1184 to notice that this set is empty and early out. */
1185 CLEAR_REG_SET (tmp);
1186 changed = bitmap_operation (tmp, bb->global_live_at_end,
1187 new_live_at_end, BITMAP_XOR);
1191 /* If any of the changed bits overlap with local_set,
1192 we'll have to rescan the block. Detect overlap by
1193 the AND with ~local_set turning off bits. */
1194 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1199 /* Let our caller know that BB changed enough to require its
1200 death notes updated. */
1202 SET_BIT (blocks_out, bb->index);
1206 /* Add to live_at_start the set of all registers in
1207 new_live_at_end that aren't in the old live_at_end. */
1209 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1211 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1213 changed = bitmap_operation (bb->global_live_at_start,
1214 bb->global_live_at_start,
1221 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1223 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1224 into live_at_start. */
1225 propagate_block (bb, new_live_at_end, bb->local_set,
1226 bb->cond_local_set, flags);
1228 /* If live_at start didn't change, no need to go farther. */
1229 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1232 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1235 /* Queue all predecessors of BB so that we may re-examine
1236 their live_at_end. */
1237 for (e = bb->pred; e; e = e->pred_next)
1239 basic_block pb = e->src;
1240 if (pb->aux == NULL)
1251 FREE_REG_SET (new_live_at_end);
1252 FREE_REG_SET (call_used);
1256 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1258 basic_block bb = BASIC_BLOCK (i);
1259 FREE_REG_SET (bb->local_set);
1260 FREE_REG_SET (bb->cond_local_set);
1265 for (i = n_basic_blocks - 1; i >= 0; --i)
1267 basic_block bb = BASIC_BLOCK (i);
1268 FREE_REG_SET (bb->local_set);
1269 FREE_REG_SET (bb->cond_local_set);
1276 /* Subroutines of life analysis. */
1278 /* Allocate the permanent data structures that represent the results
1279 of life analysis. Not static since used also for stupid life analysis. */
1282 allocate_bb_life_data ()
1286 for (i = 0; i < n_basic_blocks; i++)
1288 basic_block bb = BASIC_BLOCK (i);
1290 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1291 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1294 ENTRY_BLOCK_PTR->global_live_at_end
1295 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1296 EXIT_BLOCK_PTR->global_live_at_start
1297 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1299 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1303 allocate_reg_life_data ()
1307 max_regno = max_reg_num ();
1309 /* Recalculate the register space, in case it has grown. Old style
1310 vector oriented regsets would set regset_{size,bytes} here also. */
1311 allocate_reg_info (max_regno, FALSE, FALSE);
1313 /* Reset all the data we'll collect in propagate_block and its
1315 for (i = 0; i < max_regno; i++)
1319 REG_N_DEATHS (i) = 0;
1320 REG_N_CALLS_CROSSED (i) = 0;
1321 REG_LIVE_LENGTH (i) = 0;
1322 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1326 /* Delete dead instructions for propagate_block. */
1329 propagate_block_delete_insn (bb, insn)
1333 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1335 /* If the insn referred to a label, and that label was attached to
1336 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1337 pretty much mandatory to delete it, because the ADDR_VEC may be
1338 referencing labels that no longer exist.
1340 INSN may reference a deleted label, particularly when a jump
1341 table has been optimized into a direct jump. There's no
1342 real good way to fix up the reference to the deleted label
1343 when the label is deleted, so we just allow it here.
1345 After dead code elimination is complete, we do search for
1346 any REG_LABEL notes which reference deleted labels as a
1349 if (inote && GET_CODE (inote) == CODE_LABEL)
1351 rtx label = XEXP (inote, 0);
1354 /* The label may be forced if it has been put in the constant
1355 pool. If that is the only use we must discard the table
1356 jump following it, but not the label itself. */
1357 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1358 && (next = next_nonnote_insn (label)) != NULL
1359 && GET_CODE (next) == JUMP_INSN
1360 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1361 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1363 rtx pat = PATTERN (next);
1364 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1365 int len = XVECLEN (pat, diff_vec_p);
1368 for (i = 0; i < len; i++)
1369 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1371 flow_delete_insn (next);
1375 if (bb->end == insn)
1377 bb->end = PREV_INSN (insn);
1378 purge_dead_edges (bb);
1380 flow_delete_insn (insn);
1383 /* Delete dead libcalls for propagate_block. Return the insn
1384 before the libcall. */
1387 propagate_block_delete_libcall (bb, insn, note)
1391 rtx first = XEXP (note, 0);
1392 rtx before = PREV_INSN (first);
1394 if (insn == bb->end)
1397 flow_delete_insn_chain (first, insn);
1401 /* Update the life-status of regs for one insn. Return the previous insn. */
1404 propagate_one_insn (pbi, insn)
1405 struct propagate_block_info *pbi;
1408 rtx prev = PREV_INSN (insn);
1409 int flags = pbi->flags;
1410 int insn_is_dead = 0;
1411 int libcall_is_dead = 0;
1415 if (! INSN_P (insn))
1418 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1419 if (flags & PROP_SCAN_DEAD_CODE)
1421 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1422 libcall_is_dead = (insn_is_dead && note != 0
1423 && libcall_dead_p (pbi, note, insn));
1426 /* If an instruction consists of just dead store(s) on final pass,
1428 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1430 /* If we're trying to delete a prologue or epilogue instruction
1431 that isn't flagged as possibly being dead, something is wrong.
1432 But if we are keeping the stack pointer depressed, we might well
1433 be deleting insns that are used to compute the amount to update
1434 it by, so they are fine. */
1435 if (reload_completed
1436 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1437 && (TYPE_RETURNS_STACK_DEPRESSED
1438 (TREE_TYPE (current_function_decl))))
1439 && (((HAVE_epilogue || HAVE_prologue)
1440 && prologue_epilogue_contains (insn))
1441 || (HAVE_sibcall_epilogue
1442 && sibcall_epilogue_contains (insn)))
1443 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1446 /* Record sets. Do this even for dead instructions, since they
1447 would have killed the values if they hadn't been deleted. */
1448 mark_set_regs (pbi, PATTERN (insn), insn);
1450 /* CC0 is now known to be dead. Either this insn used it,
1451 in which case it doesn't anymore, or clobbered it,
1452 so the next insn can't use it. */
1455 if (libcall_is_dead)
1456 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
1458 propagate_block_delete_insn (pbi->bb, insn);
1463 /* See if this is an increment or decrement that can be merged into
1464 a following memory address. */
1467 register rtx x = single_set (insn);
1469 /* Does this instruction increment or decrement a register? */
1470 if ((flags & PROP_AUTOINC)
1472 && GET_CODE (SET_DEST (x)) == REG
1473 && (GET_CODE (SET_SRC (x)) == PLUS
1474 || GET_CODE (SET_SRC (x)) == MINUS)
1475 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1476 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1477 /* Ok, look for a following memory ref we can combine with.
1478 If one is found, change the memory ref to a PRE_INC
1479 or PRE_DEC, cancel this insn, and return 1.
1480 Return 0 if nothing has been done. */
1481 && try_pre_increment_1 (pbi, insn))
1484 #endif /* AUTO_INC_DEC */
1486 CLEAR_REG_SET (pbi->new_set);
1488 /* If this is not the final pass, and this insn is copying the value of
1489 a library call and it's dead, don't scan the insns that perform the
1490 library call, so that the call's arguments are not marked live. */
1491 if (libcall_is_dead)
1493 /* Record the death of the dest reg. */
1494 mark_set_regs (pbi, PATTERN (insn), insn);
1496 insn = XEXP (note, 0);
1497 return PREV_INSN (insn);
1499 else if (GET_CODE (PATTERN (insn)) == SET
1500 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1501 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1502 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1503 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1504 /* We have an insn to pop a constant amount off the stack.
1505 (Such insns use PLUS regardless of the direction of the stack,
1506 and any insn to adjust the stack by a constant is always a pop.)
1507 These insns, if not dead stores, have no effect on life. */
1511 /* Any regs live at the time of a call instruction must not go
1512 in a register clobbered by calls. Find all regs now live and
1513 record this for them. */
1515 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1516 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1517 { REG_N_CALLS_CROSSED (i)++; });
1519 /* Record sets. Do this even for dead instructions, since they
1520 would have killed the values if they hadn't been deleted. */
1521 mark_set_regs (pbi, PATTERN (insn), insn);
1523 if (GET_CODE (insn) == CALL_INSN)
1529 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1530 cond = COND_EXEC_TEST (PATTERN (insn));
1532 /* Non-constant calls clobber memory. */
1533 if (! CONST_OR_PURE_CALL_P (insn))
1535 free_EXPR_LIST_list (&pbi->mem_set_list);
1536 pbi->mem_set_list_len = 0;
1539 /* There may be extra registers to be clobbered. */
1540 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1542 note = XEXP (note, 1))
1543 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1544 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1545 cond, insn, pbi->flags);
1547 /* Calls change all call-used and global registers. */
1548 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1549 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1551 /* We do not want REG_UNUSED notes for these registers. */
1552 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1554 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1558 /* If an insn doesn't use CC0, it becomes dead since we assume
1559 that every insn clobbers it. So show it dead here;
1560 mark_used_regs will set it live if it is referenced. */
1565 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1567 /* Sometimes we may have inserted something before INSN (such as a move)
1568 when we make an auto-inc. So ensure we will scan those insns. */
1570 prev = PREV_INSN (insn);
1573 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1579 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1580 cond = COND_EXEC_TEST (PATTERN (insn));
1582 /* Calls use their arguments. */
1583 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1585 note = XEXP (note, 1))
1586 if (GET_CODE (XEXP (note, 0)) == USE)
1587 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1590 /* The stack ptr is used (honorarily) by a CALL insn. */
1591 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1593 /* Calls may also reference any of the global registers,
1594 so they are made live. */
1595 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1597 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1602 /* On final pass, update counts of how many insns in which each reg
1604 if (flags & PROP_REG_INFO)
1605 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1606 { REG_LIVE_LENGTH (i)++; });
1611 /* Initialize a propagate_block_info struct for public consumption.
1612 Note that the structure itself is opaque to this file, but that
1613 the user can use the regsets provided here. */
1615 struct propagate_block_info *
1616 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1618 regset live, local_set, cond_local_set;
1621 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1624 pbi->reg_live = live;
1625 pbi->mem_set_list = NULL_RTX;
1626 pbi->mem_set_list_len = 0;
1627 pbi->local_set = local_set;
1628 pbi->cond_local_set = cond_local_set;
1632 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1633 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1635 pbi->reg_next_use = NULL;
1637 pbi->new_set = BITMAP_XMALLOC ();
1639 #ifdef HAVE_conditional_execution
1640 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1641 free_reg_cond_life_info);
1642 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1644 /* If this block ends in a conditional branch, for each register live
1645 from one side of the branch and not the other, record the register
1646 as conditionally dead. */
1647 if (GET_CODE (bb->end) == JUMP_INSN
1648 && any_condjump_p (bb->end))
1650 regset_head diff_head;
1651 regset diff = INITIALIZE_REG_SET (diff_head);
1652 basic_block bb_true, bb_false;
1653 rtx cond_true, cond_false, set_src;
1656 /* Identify the successor blocks. */
1657 bb_true = bb->succ->dest;
1658 if (bb->succ->succ_next != NULL)
1660 bb_false = bb->succ->succ_next->dest;
1662 if (bb->succ->flags & EDGE_FALLTHRU)
1664 basic_block t = bb_false;
1668 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1673 /* This can happen with a conditional jump to the next insn. */
1674 if (JUMP_LABEL (bb->end) != bb_true->head)
1677 /* Simplest way to do nothing. */
1681 /* Extract the condition from the branch. */
1682 set_src = SET_SRC (pc_set (bb->end));
1683 cond_true = XEXP (set_src, 0);
1684 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1685 GET_MODE (cond_true), XEXP (cond_true, 0),
1686 XEXP (cond_true, 1));
1687 if (GET_CODE (XEXP (set_src, 1)) == PC)
1690 cond_false = cond_true;
1694 /* Compute which register lead different lives in the successors. */
1695 if (bitmap_operation (diff, bb_true->global_live_at_start,
1696 bb_false->global_live_at_start, BITMAP_XOR))
1698 rtx reg = XEXP (cond_true, 0);
1700 if (GET_CODE (reg) == SUBREG)
1701 reg = SUBREG_REG (reg);
1703 if (GET_CODE (reg) != REG)
1706 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1708 /* For each such register, mark it conditionally dead. */
1709 EXECUTE_IF_SET_IN_REG_SET
1712 struct reg_cond_life_info *rcli;
1715 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1717 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1721 rcli->condition = cond;
1722 rcli->stores = const0_rtx;
1723 rcli->orig_condition = cond;
1725 splay_tree_insert (pbi->reg_cond_dead, i,
1726 (splay_tree_value) rcli);
1730 FREE_REG_SET (diff);
1734 /* If this block has no successors, any stores to the frame that aren't
1735 used later in the block are dead. So make a pass over the block
1736 recording any such that are made and show them dead at the end. We do
1737 a very conservative and simple job here. */
1739 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1740 && (TYPE_RETURNS_STACK_DEPRESSED
1741 (TREE_TYPE (current_function_decl))))
1742 && (flags & PROP_SCAN_DEAD_CODE)
1743 && (bb->succ == NULL
1744 || (bb->succ->succ_next == NULL
1745 && bb->succ->dest == EXIT_BLOCK_PTR
1746 && ! current_function_calls_eh_return)))
1749 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1750 if (GET_CODE (insn) == INSN
1751 && (set = single_set (insn))
1752 && GET_CODE (SET_DEST (set)) == MEM)
1754 rtx mem = SET_DEST (set);
1755 rtx canon_mem = canon_rtx (mem);
1757 /* This optimization is performed by faking a store to the
1758 memory at the end of the block. This doesn't work for
1759 unchanging memories because multiple stores to unchanging
1760 memory is illegal and alias analysis doesn't consider it. */
1761 if (RTX_UNCHANGING_P (canon_mem))
1764 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1765 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1766 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1767 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1768 add_to_mem_set_list (pbi, canon_mem);
1775 /* Release a propagate_block_info struct. */
1778 free_propagate_block_info (pbi)
1779 struct propagate_block_info *pbi;
1781 free_EXPR_LIST_list (&pbi->mem_set_list);
1783 BITMAP_XFREE (pbi->new_set);
1785 #ifdef HAVE_conditional_execution
1786 splay_tree_delete (pbi->reg_cond_dead);
1787 BITMAP_XFREE (pbi->reg_cond_reg);
1790 if (pbi->reg_next_use)
1791 free (pbi->reg_next_use);
1796 /* Compute the registers live at the beginning of a basic block BB from
1797 those live at the end.
1799 When called, REG_LIVE contains those live at the end. On return, it
1800 contains those live at the beginning.
1802 LOCAL_SET, if non-null, will be set with all registers killed
1803 unconditionally by this basic block.
1804 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1805 killed conditionally by this basic block. If there is any unconditional
1806 set of a register, then the corresponding bit will be set in LOCAL_SET
1807 and cleared in COND_LOCAL_SET.
1808 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1809 case, the resulting set will be equal to the union of the two sets that
1810 would otherwise be computed.
1812 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1815 propagate_block (bb, live, local_set, cond_local_set, flags)
1819 regset cond_local_set;
1822 struct propagate_block_info *pbi;
1826 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
1828 if (flags & PROP_REG_INFO)
1832 /* Process the regs live at the end of the block.
1833 Mark them as not local to any one basic block. */
1834 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
1835 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
1838 /* Scan the block an insn at a time from end to beginning. */
1841 for (insn = bb->end;; insn = prev)
1843 /* If this is a call to `setjmp' et al, warn if any
1844 non-volatile datum is live. */
1845 if ((flags & PROP_REG_INFO)
1846 && GET_CODE (insn) == CALL_INSN
1847 && find_reg_note (insn, REG_SETJMP, NULL))
1848 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
1850 prev = propagate_one_insn (pbi, insn);
1851 changed |= NEXT_INSN (prev) != insn;
1853 if (insn == bb->head)
1857 free_propagate_block_info (pbi);
1862 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1863 (SET expressions whose destinations are registers dead after the insn).
1864 NEEDED is the regset that says which regs are alive after the insn.
1866 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1868 If X is the entire body of an insn, NOTES contains the reg notes
1869 pertaining to the insn. */
1872 insn_dead_p (pbi, x, call_ok, notes)
1873 struct propagate_block_info *pbi;
1876 rtx notes ATTRIBUTE_UNUSED;
1878 enum rtx_code code = GET_CODE (x);
1881 /* If flow is invoked after reload, we must take existing AUTO_INC
1882 expresions into account. */
1883 if (reload_completed)
1885 for (; notes; notes = XEXP (notes, 1))
1887 if (REG_NOTE_KIND (notes) == REG_INC)
1889 int regno = REGNO (XEXP (notes, 0));
1891 /* Don't delete insns to set global regs. */
1892 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1893 || REGNO_REG_SET_P (pbi->reg_live, regno))
1900 /* If setting something that's a reg or part of one,
1901 see if that register's altered value will be live. */
1905 rtx r = SET_DEST (x);
1908 if (GET_CODE (r) == CC0)
1909 return ! pbi->cc0_live;
1912 /* A SET that is a subroutine call cannot be dead. */
1913 if (GET_CODE (SET_SRC (x)) == CALL)
1919 /* Don't eliminate loads from volatile memory or volatile asms. */
1920 else if (volatile_refs_p (SET_SRC (x)))
1923 if (GET_CODE (r) == MEM)
1927 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
1930 canon_r = canon_rtx (r);
1932 /* Walk the set of memory locations we are currently tracking
1933 and see if one is an identical match to this memory location.
1934 If so, this memory write is dead (remember, we're walking
1935 backwards from the end of the block to the start). Since
1936 rtx_equal_p does not check the alias set or flags, we also
1937 must have the potential for them to conflict (anti_dependence). */
1938 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
1939 if (anti_dependence (r, XEXP (temp, 0)))
1941 rtx mem = XEXP (temp, 0);
1943 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
1944 && (GET_MODE_SIZE (GET_MODE (canon_r))
1945 <= GET_MODE_SIZE (GET_MODE (mem))))
1949 /* Check if memory reference matches an auto increment. Only
1950 post increment/decrement or modify are valid. */
1951 if (GET_MODE (mem) == GET_MODE (r)
1952 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
1953 || GET_CODE (XEXP (mem, 0)) == POST_INC
1954 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
1955 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
1956 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
1963 while (GET_CODE (r) == SUBREG
1964 || GET_CODE (r) == STRICT_LOW_PART
1965 || GET_CODE (r) == ZERO_EXTRACT)
1968 if (GET_CODE (r) == REG)
1970 int regno = REGNO (r);
1973 if (REGNO_REG_SET_P (pbi->reg_live, regno))
1976 /* If this is a hard register, verify that subsequent
1977 words are not needed. */
1978 if (regno < FIRST_PSEUDO_REGISTER)
1980 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
1983 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
1987 /* Don't delete insns to set global regs. */
1988 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
1991 /* Make sure insns to set the stack pointer aren't deleted. */
1992 if (regno == STACK_POINTER_REGNUM)
1995 /* ??? These bits might be redundant with the force live bits
1996 in calculate_global_regs_live. We would delete from
1997 sequential sets; whether this actually affects real code
1998 for anything but the stack pointer I don't know. */
1999 /* Make sure insns to set the frame pointer aren't deleted. */
2000 if (regno == FRAME_POINTER_REGNUM
2001 && (! reload_completed || frame_pointer_needed))
2003 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2004 if (regno == HARD_FRAME_POINTER_REGNUM
2005 && (! reload_completed || frame_pointer_needed))
2009 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2010 /* Make sure insns to set arg pointer are never deleted
2011 (if the arg pointer isn't fixed, there will be a USE
2012 for it, so we can treat it normally). */
2013 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2017 /* Otherwise, the set is dead. */
2023 /* If performing several activities, insn is dead if each activity
2024 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2025 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2027 else if (code == PARALLEL)
2029 int i = XVECLEN (x, 0);
2031 for (i--; i >= 0; i--)
2032 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2033 && GET_CODE (XVECEXP (x, 0, i)) != USE
2034 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2040 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2041 is not necessarily true for hard registers. */
2042 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2043 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2044 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2047 /* We do not check other CLOBBER or USE here. An insn consisting of just
2048 a CLOBBER or just a USE should not be deleted. */
2052 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2053 return 1 if the entire library call is dead.
2054 This is true if INSN copies a register (hard or pseudo)
2055 and if the hard return reg of the call insn is dead.
2056 (The caller should have tested the destination of the SET inside
2057 INSN already for death.)
2059 If this insn doesn't just copy a register, then we don't
2060 have an ordinary libcall. In that case, cse could not have
2061 managed to substitute the source for the dest later on,
2062 so we can assume the libcall is dead.
2064 PBI is the block info giving pseudoregs live before this insn.
2065 NOTE is the REG_RETVAL note of the insn. */
2068 libcall_dead_p (pbi, note, insn)
2069 struct propagate_block_info *pbi;
2073 rtx x = single_set (insn);
2077 register rtx r = SET_SRC (x);
2079 if (GET_CODE (r) == REG)
2081 rtx call = XEXP (note, 0);
2085 /* Find the call insn. */
2086 while (call != insn && GET_CODE (call) != CALL_INSN)
2087 call = NEXT_INSN (call);
2089 /* If there is none, do nothing special,
2090 since ordinary death handling can understand these insns. */
2094 /* See if the hard reg holding the value is dead.
2095 If this is a PARALLEL, find the call within it. */
2096 call_pat = PATTERN (call);
2097 if (GET_CODE (call_pat) == PARALLEL)
2099 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2100 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2101 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2104 /* This may be a library call that is returning a value
2105 via invisible pointer. Do nothing special, since
2106 ordinary death handling can understand these insns. */
2110 call_pat = XVECEXP (call_pat, 0, i);
2113 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2119 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2120 live at function entry. Don't count global register variables, variables
2121 in registers that can be used for function arg passing, or variables in
2122 fixed hard registers. */
2125 regno_uninitialized (regno)
2128 if (n_basic_blocks == 0
2129 || (regno < FIRST_PSEUDO_REGISTER
2130 && (global_regs[regno]
2131 || fixed_regs[regno]
2132 || FUNCTION_ARG_REGNO_P (regno))))
2135 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
2138 /* 1 if register REGNO was alive at a place where `setjmp' was called
2139 and was set more than once or is an argument.
2140 Such regs may be clobbered by `longjmp'. */
2143 regno_clobbered_at_setjmp (regno)
2146 if (n_basic_blocks == 0)
2149 return ((REG_N_SETS (regno) > 1
2150 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
2151 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2154 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2155 maximal list size; look for overlaps in mode and select the largest. */
2157 add_to_mem_set_list (pbi, mem)
2158 struct propagate_block_info *pbi;
2163 /* We don't know how large a BLKmode store is, so we must not
2164 take them into consideration. */
2165 if (GET_MODE (mem) == BLKmode)
2168 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2170 rtx e = XEXP (i, 0);
2171 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2173 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2176 /* If we must store a copy of the mem, we can just modify
2177 the mode of the stored copy. */
2178 if (pbi->flags & PROP_AUTOINC)
2179 PUT_MODE (e, GET_MODE (mem));
2188 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2191 /* Store a copy of mem, otherwise the address may be
2192 scrogged by find_auto_inc. */
2193 if (pbi->flags & PROP_AUTOINC)
2194 mem = shallow_copy_rtx (mem);
2196 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2197 pbi->mem_set_list_len++;
2201 /* INSN references memory, possibly using autoincrement addressing modes.
2202 Find any entries on the mem_set_list that need to be invalidated due
2203 to an address change. */
2206 invalidate_mems_from_autoinc (pbi, insn)
2207 struct propagate_block_info *pbi;
2210 rtx note = REG_NOTES (insn);
2211 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2212 if (REG_NOTE_KIND (note) == REG_INC)
2213 invalidate_mems_from_set (pbi, XEXP (note, 0));
2216 /* EXP is a REG. Remove any dependant entries from pbi->mem_set_list. */
2219 invalidate_mems_from_set (pbi, exp)
2220 struct propagate_block_info *pbi;
2223 rtx temp = pbi->mem_set_list;
2224 rtx prev = NULL_RTX;
2229 next = XEXP (temp, 1);
2230 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2232 /* Splice this entry out of the list. */
2234 XEXP (prev, 1) = next;
2236 pbi->mem_set_list = next;
2237 free_EXPR_LIST_node (temp);
2238 pbi->mem_set_list_len--;
2246 /* Process the registers that are set within X. Their bits are set to
2247 1 in the regset DEAD, because they are dead prior to this insn.
2249 If INSN is nonzero, it is the insn being processed.
2251 FLAGS is the set of operations to perform. */
2254 mark_set_regs (pbi, x, insn)
2255 struct propagate_block_info *pbi;
2258 rtx cond = NULL_RTX;
2263 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2265 if (REG_NOTE_KIND (link) == REG_INC)
2266 mark_set_1 (pbi, SET, XEXP (link, 0),
2267 (GET_CODE (x) == COND_EXEC
2268 ? COND_EXEC_TEST (x) : NULL_RTX),
2272 switch (code = GET_CODE (x))
2276 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2280 cond = COND_EXEC_TEST (x);
2281 x = COND_EXEC_CODE (x);
2287 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2289 rtx sub = XVECEXP (x, 0, i);
2290 switch (code = GET_CODE (sub))
2293 if (cond != NULL_RTX)
2296 cond = COND_EXEC_TEST (sub);
2297 sub = COND_EXEC_CODE (sub);
2298 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2304 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2319 /* Process a single set, which appears in INSN. REG (which may not
2320 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2321 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2322 If the set is conditional (because it appear in a COND_EXEC), COND
2323 will be the condition. */
2326 mark_set_1 (pbi, code, reg, cond, insn, flags)
2327 struct propagate_block_info *pbi;
2329 rtx reg, cond, insn;
2332 int regno_first = -1, regno_last = -1;
2333 unsigned long not_dead = 0;
2336 /* Modifying just one hardware register of a multi-reg value or just a
2337 byte field of a register does not mean the value from before this insn
2338 is now dead. Of course, if it was dead after it's unused now. */
2340 switch (GET_CODE (reg))
2343 /* Some targets place small structures in registers for return values of
2344 functions. We have to detect this case specially here to get correct
2345 flow information. */
2346 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2347 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2348 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2354 case STRICT_LOW_PART:
2355 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2357 reg = XEXP (reg, 0);
2358 while (GET_CODE (reg) == SUBREG
2359 || GET_CODE (reg) == ZERO_EXTRACT
2360 || GET_CODE (reg) == SIGN_EXTRACT
2361 || GET_CODE (reg) == STRICT_LOW_PART);
2362 if (GET_CODE (reg) == MEM)
2364 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2368 regno_last = regno_first = REGNO (reg);
2369 if (regno_first < FIRST_PSEUDO_REGISTER)
2370 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2374 if (GET_CODE (SUBREG_REG (reg)) == REG)
2376 enum machine_mode outer_mode = GET_MODE (reg);
2377 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2379 /* Identify the range of registers affected. This is moderately
2380 tricky for hard registers. See alter_subreg. */
2382 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2383 if (regno_first < FIRST_PSEUDO_REGISTER)
2385 regno_first += subreg_regno_offset (regno_first, inner_mode,
2388 regno_last = (regno_first
2389 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2391 /* Since we've just adjusted the register number ranges, make
2392 sure REG matches. Otherwise some_was_live will be clear
2393 when it shouldn't have been, and we'll create incorrect
2394 REG_UNUSED notes. */
2395 reg = gen_rtx_REG (outer_mode, regno_first);
2399 /* If the number of words in the subreg is less than the number
2400 of words in the full register, we have a well-defined partial
2401 set. Otherwise the high bits are undefined.
2403 This is only really applicable to pseudos, since we just took
2404 care of multi-word hard registers. */
2405 if (((GET_MODE_SIZE (outer_mode)
2406 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2407 < ((GET_MODE_SIZE (inner_mode)
2408 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2409 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2412 reg = SUBREG_REG (reg);
2416 reg = SUBREG_REG (reg);
2423 /* If this set is a MEM, then it kills any aliased writes.
2424 If this set is a REG, then it kills any MEMs which use the reg. */
2425 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2427 if (GET_CODE (reg) == REG)
2428 invalidate_mems_from_set (pbi, reg);
2430 /* If the memory reference had embedded side effects (autoincrement
2431 address modes. Then we may need to kill some entries on the
2433 if (insn && GET_CODE (reg) == MEM)
2434 invalidate_mems_from_autoinc (pbi, insn);
2436 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2437 /* ??? With more effort we could track conditional memory life. */
2439 /* There are no REG_INC notes for SP, so we can't assume we'll see
2440 everything that invalidates it. To be safe, don't eliminate any
2441 stores though SP; none of them should be redundant anyway. */
2442 && ! reg_mentioned_p (stack_pointer_rtx, reg))
2443 add_to_mem_set_list (pbi, canon_rtx (reg));
2446 if (GET_CODE (reg) == REG
2447 && ! (regno_first == FRAME_POINTER_REGNUM
2448 && (! reload_completed || frame_pointer_needed))
2449 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2450 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2451 && (! reload_completed || frame_pointer_needed))
2453 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2454 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2458 int some_was_live = 0, some_was_dead = 0;
2460 for (i = regno_first; i <= regno_last; ++i)
2462 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2465 /* Order of the set operation matters here since both
2466 sets may be the same. */
2467 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2468 if (cond != NULL_RTX
2469 && ! REGNO_REG_SET_P (pbi->local_set, i))
2470 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2472 SET_REGNO_REG_SET (pbi->local_set, i);
2474 if (code != CLOBBER)
2475 SET_REGNO_REG_SET (pbi->new_set, i);
2477 some_was_live |= needed_regno;
2478 some_was_dead |= ! needed_regno;
2481 #ifdef HAVE_conditional_execution
2482 /* Consider conditional death in deciding that the register needs
2484 if (some_was_live && ! not_dead
2485 /* The stack pointer is never dead. Well, not strictly true,
2486 but it's very difficult to tell from here. Hopefully
2487 combine_stack_adjustments will fix up the most egregious
2489 && regno_first != STACK_POINTER_REGNUM)
2491 for (i = regno_first; i <= regno_last; ++i)
2492 if (! mark_regno_cond_dead (pbi, i, cond))
2493 not_dead |= ((unsigned long) 1) << (i - regno_first);
2497 /* Additional data to record if this is the final pass. */
2498 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2499 | PROP_DEATH_NOTES | PROP_AUTOINC))
2502 register int blocknum = pbi->bb->index;
2505 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2507 y = pbi->reg_next_use[regno_first];
2509 /* The next use is no longer next, since a store intervenes. */
2510 for (i = regno_first; i <= regno_last; ++i)
2511 pbi->reg_next_use[i] = 0;
2514 if (flags & PROP_REG_INFO)
2516 for (i = regno_first; i <= regno_last; ++i)
2518 /* Count (weighted) references, stores, etc. This counts a
2519 register twice if it is modified, but that is correct. */
2520 REG_N_SETS (i) += 1;
2521 REG_N_REFS (i) += 1;
2522 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2524 /* The insns where a reg is live are normally counted
2525 elsewhere, but we want the count to include the insn
2526 where the reg is set, and the normal counting mechanism
2527 would not count it. */
2528 REG_LIVE_LENGTH (i) += 1;
2531 /* If this is a hard reg, record this function uses the reg. */
2532 if (regno_first < FIRST_PSEUDO_REGISTER)
2534 for (i = regno_first; i <= regno_last; i++)
2535 regs_ever_live[i] = 1;
2539 /* Keep track of which basic blocks each reg appears in. */
2540 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2541 REG_BASIC_BLOCK (regno_first) = blocknum;
2542 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2543 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2547 if (! some_was_dead)
2549 if (flags & PROP_LOG_LINKS)
2551 /* Make a logical link from the next following insn
2552 that uses this register, back to this insn.
2553 The following insns have already been processed.
2555 We don't build a LOG_LINK for hard registers containing
2556 in ASM_OPERANDs. If these registers get replaced,
2557 we might wind up changing the semantics of the insn,
2558 even if reload can make what appear to be valid
2559 assignments later. */
2560 if (y && (BLOCK_NUM (y) == blocknum)
2561 && (regno_first >= FIRST_PSEUDO_REGISTER
2562 || asm_noperands (PATTERN (y)) < 0))
2563 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2568 else if (! some_was_live)
2570 if (flags & PROP_REG_INFO)
2571 REG_N_DEATHS (regno_first) += 1;
2573 if (flags & PROP_DEATH_NOTES)
2575 /* Note that dead stores have already been deleted
2576 when possible. If we get here, we have found a
2577 dead store that cannot be eliminated (because the
2578 same insn does something useful). Indicate this
2579 by marking the reg being set as dying here. */
2581 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2586 if (flags & PROP_DEATH_NOTES)
2588 /* This is a case where we have a multi-word hard register
2589 and some, but not all, of the words of the register are
2590 needed in subsequent insns. Write REG_UNUSED notes
2591 for those parts that were not needed. This case should
2594 for (i = regno_first; i <= regno_last; ++i)
2595 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2597 = alloc_EXPR_LIST (REG_UNUSED,
2598 gen_rtx_REG (reg_raw_mode[i], i),
2604 /* Mark the register as being dead. */
2606 /* The stack pointer is never dead. Well, not strictly true,
2607 but it's very difficult to tell from here. Hopefully
2608 combine_stack_adjustments will fix up the most egregious
2610 && regno_first != STACK_POINTER_REGNUM)
2612 for (i = regno_first; i <= regno_last; ++i)
2613 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2614 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2617 else if (GET_CODE (reg) == REG)
2619 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2620 pbi->reg_next_use[regno_first] = 0;
2623 /* If this is the last pass and this is a SCRATCH, show it will be dying
2624 here and count it. */
2625 else if (GET_CODE (reg) == SCRATCH)
2627 if (flags & PROP_DEATH_NOTES)
2629 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2633 #ifdef HAVE_conditional_execution
2634 /* Mark REGNO conditionally dead.
2635 Return true if the register is now unconditionally dead. */
2638 mark_regno_cond_dead (pbi, regno, cond)
2639 struct propagate_block_info *pbi;
2643 /* If this is a store to a predicate register, the value of the
2644 predicate is changing, we don't know that the predicate as seen
2645 before is the same as that seen after. Flush all dependent
2646 conditions from reg_cond_dead. This will make all such
2647 conditionally live registers unconditionally live. */
2648 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2649 flush_reg_cond_reg (pbi, regno);
2651 /* If this is an unconditional store, remove any conditional
2652 life that may have existed. */
2653 if (cond == NULL_RTX)
2654 splay_tree_remove (pbi->reg_cond_dead, regno);
2657 splay_tree_node node;
2658 struct reg_cond_life_info *rcli;
2661 /* Otherwise this is a conditional set. Record that fact.
2662 It may have been conditionally used, or there may be a
2663 subsequent set with a complimentary condition. */
2665 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2668 /* The register was unconditionally live previously.
2669 Record the current condition as the condition under
2670 which it is dead. */
2671 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2672 rcli->condition = cond;
2673 rcli->stores = cond;
2674 rcli->orig_condition = const0_rtx;
2675 splay_tree_insert (pbi->reg_cond_dead, regno,
2676 (splay_tree_value) rcli);
2678 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2680 /* Not unconditionaly dead. */
2685 /* The register was conditionally live previously.
2686 Add the new condition to the old. */
2687 rcli = (struct reg_cond_life_info *) node->value;
2688 ncond = rcli->condition;
2689 ncond = ior_reg_cond (ncond, cond, 1);
2690 if (rcli->stores == const0_rtx)
2691 rcli->stores = cond;
2692 else if (rcli->stores != const1_rtx)
2693 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2695 /* If the register is now unconditionally dead, remove the entry
2696 in the splay_tree. A register is unconditionally dead if the
2697 dead condition ncond is true. A register is also unconditionally
2698 dead if the sum of all conditional stores is an unconditional
2699 store (stores is true), and the dead condition is identically the
2700 same as the original dead condition initialized at the end of
2701 the block. This is a pointer compare, not an rtx_equal_p
2703 if (ncond == const1_rtx
2704 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2705 splay_tree_remove (pbi->reg_cond_dead, regno);
2708 rcli->condition = ncond;
2710 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2712 /* Not unconditionaly dead. */
2721 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2724 free_reg_cond_life_info (value)
2725 splay_tree_value value;
2727 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2731 /* Helper function for flush_reg_cond_reg. */
2734 flush_reg_cond_reg_1 (node, data)
2735 splay_tree_node node;
2738 struct reg_cond_life_info *rcli;
2739 int *xdata = (int *) data;
2740 unsigned int regno = xdata[0];
2742 /* Don't need to search if last flushed value was farther on in
2743 the in-order traversal. */
2744 if (xdata[1] >= (int) node->key)
2747 /* Splice out portions of the expression that refer to regno. */
2748 rcli = (struct reg_cond_life_info *) node->value;
2749 rcli->condition = elim_reg_cond (rcli->condition, regno);
2750 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2751 rcli->stores = elim_reg_cond (rcli->stores, regno);
2753 /* If the entire condition is now false, signal the node to be removed. */
2754 if (rcli->condition == const0_rtx)
2756 xdata[1] = node->key;
2759 else if (rcli->condition == const1_rtx)
2765 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2768 flush_reg_cond_reg (pbi, regno)
2769 struct propagate_block_info *pbi;
2776 while (splay_tree_foreach (pbi->reg_cond_dead,
2777 flush_reg_cond_reg_1, pair) == -1)
2778 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2780 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2783 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2784 For ior/and, the ADD flag determines whether we want to add the new
2785 condition X to the old one unconditionally. If it is zero, we will
2786 only return a new expression if X allows us to simplify part of
2787 OLD, otherwise we return OLD unchanged to the caller.
2788 If ADD is nonzero, we will return a new condition in all cases. The
2789 toplevel caller of one of these functions should always pass 1 for
2793 ior_reg_cond (old, x, add)
2799 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2801 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2802 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2803 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2805 if (GET_CODE (x) == GET_CODE (old)
2806 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2810 return gen_rtx_IOR (0, old, x);
2813 switch (GET_CODE (old))
2816 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2817 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2818 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2820 if (op0 == const0_rtx)
2822 if (op1 == const0_rtx)
2824 if (op0 == const1_rtx || op1 == const1_rtx)
2826 if (op0 == XEXP (old, 0))
2827 op0 = gen_rtx_IOR (0, op0, x);
2829 op1 = gen_rtx_IOR (0, op1, x);
2830 return gen_rtx_IOR (0, op0, op1);
2834 return gen_rtx_IOR (0, old, x);
2837 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2838 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2839 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2841 if (op0 == const1_rtx)
2843 if (op1 == const1_rtx)
2845 if (op0 == const0_rtx || op1 == const0_rtx)
2847 if (op0 == XEXP (old, 0))
2848 op0 = gen_rtx_IOR (0, op0, x);
2850 op1 = gen_rtx_IOR (0, op1, x);
2851 return gen_rtx_AND (0, op0, op1);
2855 return gen_rtx_IOR (0, old, x);
2858 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2859 if (op0 != XEXP (old, 0))
2860 return not_reg_cond (op0);
2863 return gen_rtx_IOR (0, old, x);
2874 enum rtx_code x_code;
2876 if (x == const0_rtx)
2878 else if (x == const1_rtx)
2880 x_code = GET_CODE (x);
2883 if (GET_RTX_CLASS (x_code) == '<'
2884 && GET_CODE (XEXP (x, 0)) == REG)
2886 if (XEXP (x, 1) != const0_rtx)
2889 return gen_rtx_fmt_ee (reverse_condition (x_code),
2890 VOIDmode, XEXP (x, 0), const0_rtx);
2892 return gen_rtx_NOT (0, x);
2896 and_reg_cond (old, x, add)
2902 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2904 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2905 && GET_CODE (x) == reverse_condition (GET_CODE (old))
2906 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2908 if (GET_CODE (x) == GET_CODE (old)
2909 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2913 return gen_rtx_AND (0, old, x);
2916 switch (GET_CODE (old))
2919 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2920 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2921 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2923 if (op0 == const0_rtx)
2925 if (op1 == const0_rtx)
2927 if (op0 == const1_rtx || op1 == const1_rtx)
2929 if (op0 == XEXP (old, 0))
2930 op0 = gen_rtx_AND (0, op0, x);
2932 op1 = gen_rtx_AND (0, op1, x);
2933 return gen_rtx_IOR (0, op0, op1);
2937 return gen_rtx_AND (0, old, x);
2940 op0 = and_reg_cond (XEXP (old, 0), x, 0);
2941 op1 = and_reg_cond (XEXP (old, 1), x, 0);
2942 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
2944 if (op0 == const1_rtx)
2946 if (op1 == const1_rtx)
2948 if (op0 == const0_rtx || op1 == const0_rtx)
2950 if (op0 == XEXP (old, 0))
2951 op0 = gen_rtx_AND (0, op0, x);
2953 op1 = gen_rtx_AND (0, op1, x);
2954 return gen_rtx_AND (0, op0, op1);
2959 /* If X is identical to one of the existing terms of the AND,
2960 then just return what we already have. */
2961 /* ??? There really should be some sort of recursive check here in
2962 case there are nested ANDs. */
2963 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
2964 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
2965 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
2966 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
2969 return gen_rtx_AND (0, old, x);
2972 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2973 if (op0 != XEXP (old, 0))
2974 return not_reg_cond (op0);
2977 return gen_rtx_AND (0, old, x);
2984 /* Given a condition X, remove references to reg REGNO and return the
2985 new condition. The removal will be done so that all conditions
2986 involving REGNO are considered to evaluate to false. This function
2987 is used when the value of REGNO changes. */
2990 elim_reg_cond (x, regno)
2996 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
2998 if (REGNO (XEXP (x, 0)) == regno)
3003 switch (GET_CODE (x))
3006 op0 = elim_reg_cond (XEXP (x, 0), regno);
3007 op1 = elim_reg_cond (XEXP (x, 1), regno);
3008 if (op0 == const0_rtx || op1 == const0_rtx)
3010 if (op0 == const1_rtx)
3012 if (op1 == const1_rtx)
3014 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3016 return gen_rtx_AND (0, op0, op1);
3019 op0 = elim_reg_cond (XEXP (x, 0), regno);
3020 op1 = elim_reg_cond (XEXP (x, 1), regno);
3021 if (op0 == const1_rtx || op1 == const1_rtx)
3023 if (op0 == const0_rtx)
3025 if (op1 == const0_rtx)
3027 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3029 return gen_rtx_IOR (0, op0, op1);
3032 op0 = elim_reg_cond (XEXP (x, 0), regno);
3033 if (op0 == const0_rtx)
3035 if (op0 == const1_rtx)
3037 if (op0 != XEXP (x, 0))
3038 return not_reg_cond (op0);
3045 #endif /* HAVE_conditional_execution */
3049 /* Try to substitute the auto-inc expression INC as the address inside
3050 MEM which occurs in INSN. Currently, the address of MEM is an expression
3051 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3052 that has a single set whose source is a PLUS of INCR_REG and something
3056 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3057 struct propagate_block_info *pbi;
3058 rtx inc, insn, mem, incr, incr_reg;
3060 int regno = REGNO (incr_reg);
3061 rtx set = single_set (incr);
3062 rtx q = SET_DEST (set);
3063 rtx y = SET_SRC (set);
3064 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3066 /* Make sure this reg appears only once in this insn. */
3067 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3070 if (dead_or_set_p (incr, incr_reg)
3071 /* Mustn't autoinc an eliminable register. */
3072 && (regno >= FIRST_PSEUDO_REGISTER
3073 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3075 /* This is the simple case. Try to make the auto-inc. If
3076 we can't, we are done. Otherwise, we will do any
3077 needed updates below. */
3078 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3081 else if (GET_CODE (q) == REG
3082 /* PREV_INSN used here to check the semi-open interval
3084 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3085 /* We must also check for sets of q as q may be
3086 a call clobbered hard register and there may
3087 be a call between PREV_INSN (insn) and incr. */
3088 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3090 /* We have *p followed sometime later by q = p+size.
3091 Both p and q must be live afterward,
3092 and q is not used between INSN and its assignment.
3093 Change it to q = p, ...*q..., q = q+size.
3094 Then fall into the usual case. */
3098 emit_move_insn (q, incr_reg);
3099 insns = get_insns ();
3102 if (basic_block_for_insn)
3103 for (temp = insns; temp; temp = NEXT_INSN (temp))
3104 set_block_for_insn (temp, pbi->bb);
3106 /* If we can't make the auto-inc, or can't make the
3107 replacement into Y, exit. There's no point in making
3108 the change below if we can't do the auto-inc and doing
3109 so is not correct in the pre-inc case. */
3112 validate_change (insn, &XEXP (mem, 0), inc, 1);
3113 validate_change (incr, &XEXP (y, opnum), q, 1);
3114 if (! apply_change_group ())
3117 /* We now know we'll be doing this change, so emit the
3118 new insn(s) and do the updates. */
3119 emit_insns_before (insns, insn);
3121 if (pbi->bb->head == insn)
3122 pbi->bb->head = insns;
3124 /* INCR will become a NOTE and INSN won't contain a
3125 use of INCR_REG. If a use of INCR_REG was just placed in
3126 the insn before INSN, make that the next use.
3127 Otherwise, invalidate it. */
3128 if (GET_CODE (PREV_INSN (insn)) == INSN
3129 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3130 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3131 pbi->reg_next_use[regno] = PREV_INSN (insn);
3133 pbi->reg_next_use[regno] = 0;
3138 /* REGNO is now used in INCR which is below INSN, but
3139 it previously wasn't live here. If we don't mark
3140 it as live, we'll put a REG_DEAD note for it
3141 on this insn, which is incorrect. */
3142 SET_REGNO_REG_SET (pbi->reg_live, regno);
3144 /* If there are any calls between INSN and INCR, show
3145 that REGNO now crosses them. */
3146 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3147 if (GET_CODE (temp) == CALL_INSN)
3148 REG_N_CALLS_CROSSED (regno)++;
3150 /* Invalidate alias info for Q since we just changed its value. */
3151 clear_reg_alias_info (q);
3156 /* If we haven't returned, it means we were able to make the
3157 auto-inc, so update the status. First, record that this insn
3158 has an implicit side effect. */
3160 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3162 /* Modify the old increment-insn to simply copy
3163 the already-incremented value of our register. */
3164 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3167 /* If that makes it a no-op (copying the register into itself) delete
3168 it so it won't appear to be a "use" and a "set" of this
3170 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3172 /* If the original source was dead, it's dead now. */
3175 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3177 remove_note (incr, note);
3178 if (XEXP (note, 0) != incr_reg)
3179 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3182 PUT_CODE (incr, NOTE);
3183 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3184 NOTE_SOURCE_FILE (incr) = 0;
3187 if (regno >= FIRST_PSEUDO_REGISTER)
3189 /* Count an extra reference to the reg. When a reg is
3190 incremented, spilling it is worse, so we want to make
3191 that less likely. */
3192 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3194 /* Count the increment as a setting of the register,
3195 even though it isn't a SET in rtl. */
3196 REG_N_SETS (regno)++;
3200 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3204 find_auto_inc (pbi, x, insn)
3205 struct propagate_block_info *pbi;
3209 rtx addr = XEXP (x, 0);
3210 HOST_WIDE_INT offset = 0;
3211 rtx set, y, incr, inc_val;
3213 int size = GET_MODE_SIZE (GET_MODE (x));
3215 if (GET_CODE (insn) == JUMP_INSN)
3218 /* Here we detect use of an index register which might be good for
3219 postincrement, postdecrement, preincrement, or predecrement. */
3221 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3222 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3224 if (GET_CODE (addr) != REG)
3227 regno = REGNO (addr);
3229 /* Is the next use an increment that might make auto-increment? */
3230 incr = pbi->reg_next_use[regno];
3231 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3233 set = single_set (incr);
3234 if (set == 0 || GET_CODE (set) != SET)
3238 if (GET_CODE (y) != PLUS)
3241 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3242 inc_val = XEXP (y, 1);
3243 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3244 inc_val = XEXP (y, 0);
3248 if (GET_CODE (inc_val) == CONST_INT)
3250 if (HAVE_POST_INCREMENT
3251 && (INTVAL (inc_val) == size && offset == 0))
3252 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3254 else if (HAVE_POST_DECREMENT
3255 && (INTVAL (inc_val) == -size && offset == 0))
3256 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3258 else if (HAVE_PRE_INCREMENT
3259 && (INTVAL (inc_val) == size && offset == size))
3260 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3262 else if (HAVE_PRE_DECREMENT
3263 && (INTVAL (inc_val) == -size && offset == -size))
3264 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3266 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3267 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3268 gen_rtx_PLUS (Pmode,
3271 insn, x, incr, addr);
3273 else if (GET_CODE (inc_val) == REG
3274 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3278 if (HAVE_POST_MODIFY_REG && offset == 0)
3279 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3280 gen_rtx_PLUS (Pmode,
3283 insn, x, incr, addr);
3287 #endif /* AUTO_INC_DEC */
3290 mark_used_reg (pbi, reg, cond, insn)
3291 struct propagate_block_info *pbi;
3293 rtx cond ATTRIBUTE_UNUSED;
3296 unsigned int regno_first, regno_last, i;
3297 int some_was_live, some_was_dead, some_not_set;
3299 regno_last = regno_first = REGNO (reg);
3300 if (regno_first < FIRST_PSEUDO_REGISTER)
3301 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3303 /* Find out if any of this register is live after this instruction. */
3304 some_was_live = some_was_dead = 0;
3305 for (i = regno_first; i <= regno_last; ++i)
3307 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3308 some_was_live |= needed_regno;
3309 some_was_dead |= ! needed_regno;
3312 /* Find out if any of the register was set this insn. */
3314 for (i = regno_first; i <= regno_last; ++i)
3315 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3317 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3319 /* Record where each reg is used, so when the reg is set we know
3320 the next insn that uses it. */
3321 pbi->reg_next_use[regno_first] = insn;
3324 if (pbi->flags & PROP_REG_INFO)
3326 if (regno_first < FIRST_PSEUDO_REGISTER)
3328 /* If this is a register we are going to try to eliminate,
3329 don't mark it live here. If we are successful in
3330 eliminating it, it need not be live unless it is used for
3331 pseudos, in which case it will have been set live when it
3332 was allocated to the pseudos. If the register will not
3333 be eliminated, reload will set it live at that point.
3335 Otherwise, record that this function uses this register. */
3336 /* ??? The PPC backend tries to "eliminate" on the pic
3337 register to itself. This should be fixed. In the mean
3338 time, hack around it. */
3340 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3341 && (regno_first == FRAME_POINTER_REGNUM
3342 || regno_first == ARG_POINTER_REGNUM)))
3343 for (i = regno_first; i <= regno_last; ++i)
3344 regs_ever_live[i] = 1;
3348 /* Keep track of which basic block each reg appears in. */
3350 register int blocknum = pbi->bb->index;
3351 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3352 REG_BASIC_BLOCK (regno_first) = blocknum;
3353 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3354 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3356 /* Count (weighted) number of uses of each reg. */
3357 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3358 REG_N_REFS (regno_first)++;
3362 /* Record and count the insns in which a reg dies. If it is used in
3363 this insn and was dead below the insn then it dies in this insn.
3364 If it was set in this insn, we do not make a REG_DEAD note;
3365 likewise if we already made such a note. */
3366 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3370 /* Check for the case where the register dying partially
3371 overlaps the register set by this insn. */
3372 if (regno_first != regno_last)
3373 for (i = regno_first; i <= regno_last; ++i)
3374 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3376 /* If none of the words in X is needed, make a REG_DEAD note.
3377 Otherwise, we must make partial REG_DEAD notes. */
3378 if (! some_was_live)
3380 if ((pbi->flags & PROP_DEATH_NOTES)
3381 && ! find_regno_note (insn, REG_DEAD, regno_first))
3383 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3385 if (pbi->flags & PROP_REG_INFO)
3386 REG_N_DEATHS (regno_first)++;
3390 /* Don't make a REG_DEAD note for a part of a register
3391 that is set in the insn. */
3392 for (i = regno_first; i <= regno_last; ++i)
3393 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3394 && ! dead_or_set_regno_p (insn, i))
3396 = alloc_EXPR_LIST (REG_DEAD,
3397 gen_rtx_REG (reg_raw_mode[i], i),
3402 /* Mark the register as being live. */
3403 for (i = regno_first; i <= regno_last; ++i)
3405 SET_REGNO_REG_SET (pbi->reg_live, i);
3407 #ifdef HAVE_conditional_execution
3408 /* If this is a conditional use, record that fact. If it is later
3409 conditionally set, we'll know to kill the register. */
3410 if (cond != NULL_RTX)
3412 splay_tree_node node;
3413 struct reg_cond_life_info *rcli;
3418 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3421 /* The register was unconditionally live previously.
3422 No need to do anything. */
3426 /* The register was conditionally live previously.
3427 Subtract the new life cond from the old death cond. */
3428 rcli = (struct reg_cond_life_info *) node->value;
3429 ncond = rcli->condition;
3430 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3432 /* If the register is now unconditionally live,
3433 remove the entry in the splay_tree. */
3434 if (ncond == const0_rtx)
3435 splay_tree_remove (pbi->reg_cond_dead, i);
3438 rcli->condition = ncond;
3439 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3440 REGNO (XEXP (cond, 0)));
3446 /* The register was not previously live at all. Record
3447 the condition under which it is still dead. */
3448 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3449 rcli->condition = not_reg_cond (cond);
3450 rcli->stores = const0_rtx;
3451 rcli->orig_condition = const0_rtx;
3452 splay_tree_insert (pbi->reg_cond_dead, i,
3453 (splay_tree_value) rcli);
3455 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3458 else if (some_was_live)
3460 /* The register may have been conditionally live previously, but
3461 is now unconditionally live. Remove it from the conditionally
3462 dead list, so that a conditional set won't cause us to think
3464 splay_tree_remove (pbi->reg_cond_dead, i);
3470 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3471 This is done assuming the registers needed from X are those that
3472 have 1-bits in PBI->REG_LIVE.
3474 INSN is the containing instruction. If INSN is dead, this function
3478 mark_used_regs (pbi, x, cond, insn)
3479 struct propagate_block_info *pbi;
3482 register RTX_CODE code;
3484 int flags = pbi->flags;
3487 code = GET_CODE (x);
3507 /* If we are clobbering a MEM, mark any registers inside the address
3509 if (GET_CODE (XEXP (x, 0)) == MEM)
3510 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3514 /* Don't bother watching stores to mems if this is not the
3515 final pass. We'll not be deleting dead stores this round. */
3516 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3518 /* Invalidate the data for the last MEM stored, but only if MEM is
3519 something that can be stored into. */
3520 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3521 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3522 /* Needn't clear the memory set list. */
3526 rtx temp = pbi->mem_set_list;
3527 rtx prev = NULL_RTX;
3532 next = XEXP (temp, 1);
3533 if (anti_dependence (XEXP (temp, 0), x))
3535 /* Splice temp out of the list. */
3537 XEXP (prev, 1) = next;
3539 pbi->mem_set_list = next;
3540 free_EXPR_LIST_node (temp);
3541 pbi->mem_set_list_len--;
3549 /* If the memory reference had embedded side effects (autoincrement
3550 address modes. Then we may need to kill some entries on the
3553 invalidate_mems_from_autoinc (pbi, insn);
3557 if (flags & PROP_AUTOINC)
3558 find_auto_inc (pbi, x, insn);
3563 #ifdef CLASS_CANNOT_CHANGE_MODE
3564 if (GET_CODE (SUBREG_REG (x)) == REG
3565 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3566 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3567 GET_MODE (SUBREG_REG (x))))
3568 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3571 /* While we're here, optimize this case. */
3573 if (GET_CODE (x) != REG)
3578 /* See a register other than being set => mark it as needed. */
3579 mark_used_reg (pbi, x, cond, insn);
3584 register rtx testreg = SET_DEST (x);
3587 /* If storing into MEM, don't show it as being used. But do
3588 show the address as being used. */
3589 if (GET_CODE (testreg) == MEM)
3592 if (flags & PROP_AUTOINC)
3593 find_auto_inc (pbi, testreg, insn);
3595 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3596 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3600 /* Storing in STRICT_LOW_PART is like storing in a reg
3601 in that this SET might be dead, so ignore it in TESTREG.
3602 but in some other ways it is like using the reg.
3604 Storing in a SUBREG or a bit field is like storing the entire
3605 register in that if the register's value is not used
3606 then this SET is not needed. */
3607 while (GET_CODE (testreg) == STRICT_LOW_PART
3608 || GET_CODE (testreg) == ZERO_EXTRACT
3609 || GET_CODE (testreg) == SIGN_EXTRACT
3610 || GET_CODE (testreg) == SUBREG)
3612 #ifdef CLASS_CANNOT_CHANGE_MODE
3613 if (GET_CODE (testreg) == SUBREG
3614 && GET_CODE (SUBREG_REG (testreg)) == REG
3615 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3616 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3617 GET_MODE (testreg)))
3618 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3621 /* Modifying a single register in an alternate mode
3622 does not use any of the old value. But these other
3623 ways of storing in a register do use the old value. */
3624 if (GET_CODE (testreg) == SUBREG
3625 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
3630 testreg = XEXP (testreg, 0);
3633 /* If this is a store into a register or group of registers,
3634 recursively scan the value being stored. */
3636 if ((GET_CODE (testreg) == PARALLEL
3637 && GET_MODE (testreg) == BLKmode)
3638 || (GET_CODE (testreg) == REG
3639 && (regno = REGNO (testreg),
3640 ! (regno == FRAME_POINTER_REGNUM
3641 && (! reload_completed || frame_pointer_needed)))
3642 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3643 && ! (regno == HARD_FRAME_POINTER_REGNUM
3644 && (! reload_completed || frame_pointer_needed))
3646 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3647 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3652 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3653 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3660 case UNSPEC_VOLATILE:
3664 /* Traditional and volatile asm instructions must be considered to use
3665 and clobber all hard registers, all pseudo-registers and all of
3666 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3668 Consider for instance a volatile asm that changes the fpu rounding
3669 mode. An insn should not be moved across this even if it only uses
3670 pseudo-regs because it might give an incorrectly rounded result.
3672 ?!? Unfortunately, marking all hard registers as live causes massive
3673 problems for the register allocator and marking all pseudos as live
3674 creates mountains of uninitialized variable warnings.
3676 So for now, just clear the memory set list and mark any regs
3677 we can find in ASM_OPERANDS as used. */
3678 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3680 free_EXPR_LIST_list (&pbi->mem_set_list);
3681 pbi->mem_set_list_len = 0;
3684 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3685 We can not just fall through here since then we would be confused
3686 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3687 traditional asms unlike their normal usage. */
3688 if (code == ASM_OPERANDS)
3692 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3693 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3699 if (cond != NULL_RTX)
3702 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3704 cond = COND_EXEC_TEST (x);
3705 x = COND_EXEC_CODE (x);
3709 /* We _do_not_ want to scan operands of phi nodes. Operands of
3710 a phi function are evaluated only when control reaches this
3711 block along a particular edge. Therefore, regs that appear
3712 as arguments to phi should not be added to the global live at
3720 /* Recursively scan the operands of this expression. */
3723 register const char * const fmt = GET_RTX_FORMAT (code);
3726 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3730 /* Tail recursive case: save a function call level. */
3736 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3738 else if (fmt[i] == 'E')
3741 for (j = 0; j < XVECLEN (x, i); j++)
3742 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3751 try_pre_increment_1 (pbi, insn)
3752 struct propagate_block_info *pbi;
3755 /* Find the next use of this reg. If in same basic block,
3756 make it do pre-increment or pre-decrement if appropriate. */
3757 rtx x = single_set (insn);
3758 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3759 * INTVAL (XEXP (SET_SRC (x), 1)));
3760 int regno = REGNO (SET_DEST (x));
3761 rtx y = pbi->reg_next_use[regno];
3763 && SET_DEST (x) != stack_pointer_rtx
3764 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3765 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3766 mode would be better. */
3767 && ! dead_or_set_p (y, SET_DEST (x))
3768 && try_pre_increment (y, SET_DEST (x), amount))
3770 /* We have found a suitable auto-increment and already changed
3771 insn Y to do it. So flush this increment instruction. */
3772 propagate_block_delete_insn (pbi->bb, insn);
3774 /* Count a reference to this reg for the increment insn we are
3775 deleting. When a reg is incremented, spilling it is worse,
3776 so we want to make that less likely. */
3777 if (regno >= FIRST_PSEUDO_REGISTER)
3779 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3780 REG_N_SETS (regno)++;
3783 /* Flush any remembered memories depending on the value of
3784 the incremented register. */
3785 invalidate_mems_from_set (pbi, SET_DEST (x));
3792 /* Try to change INSN so that it does pre-increment or pre-decrement
3793 addressing on register REG in order to add AMOUNT to REG.
3794 AMOUNT is negative for pre-decrement.
3795 Returns 1 if the change could be made.
3796 This checks all about the validity of the result of modifying INSN. */
3799 try_pre_increment (insn, reg, amount)
3801 HOST_WIDE_INT amount;
3805 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3806 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3808 /* Nonzero if we can try to make a post-increment or post-decrement.
3809 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3810 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3811 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3814 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3817 /* From the sign of increment, see which possibilities are conceivable
3818 on this target machine. */
3819 if (HAVE_PRE_INCREMENT && amount > 0)
3821 if (HAVE_POST_INCREMENT && amount > 0)
3824 if (HAVE_PRE_DECREMENT && amount < 0)
3826 if (HAVE_POST_DECREMENT && amount < 0)
3829 if (! (pre_ok || post_ok))
3832 /* It is not safe to add a side effect to a jump insn
3833 because if the incremented register is spilled and must be reloaded
3834 there would be no way to store the incremented value back in memory. */
3836 if (GET_CODE (insn) == JUMP_INSN)
3841 use = find_use_as_address (PATTERN (insn), reg, 0);
3842 if (post_ok && (use == 0 || use == (rtx) 1))
3844 use = find_use_as_address (PATTERN (insn), reg, -amount);
3848 if (use == 0 || use == (rtx) 1)
3851 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
3854 /* See if this combination of instruction and addressing mode exists. */
3855 if (! validate_change (insn, &XEXP (use, 0),
3856 gen_rtx_fmt_e (amount > 0
3857 ? (do_post ? POST_INC : PRE_INC)
3858 : (do_post ? POST_DEC : PRE_DEC),
3862 /* Record that this insn now has an implicit side effect on X. */
3863 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
3867 #endif /* AUTO_INC_DEC */
3869 /* Find the place in the rtx X where REG is used as a memory address.
3870 Return the MEM rtx that so uses it.
3871 If PLUSCONST is nonzero, search instead for a memory address equivalent to
3872 (plus REG (const_int PLUSCONST)).
3874 If such an address does not appear, return 0.
3875 If REG appears more than once, or is used other than in such an address,
3879 find_use_as_address (x, reg, plusconst)
3882 HOST_WIDE_INT plusconst;
3884 enum rtx_code code = GET_CODE (x);
3885 const char * const fmt = GET_RTX_FORMAT (code);
3887 register rtx value = 0;
3890 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
3893 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
3894 && XEXP (XEXP (x, 0), 0) == reg
3895 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
3896 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
3899 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
3901 /* If REG occurs inside a MEM used in a bit-field reference,
3902 that is unacceptable. */
3903 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
3904 return (rtx) (HOST_WIDE_INT) 1;
3908 return (rtx) (HOST_WIDE_INT) 1;
3910 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3914 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
3918 return (rtx) (HOST_WIDE_INT) 1;
3920 else if (fmt[i] == 'E')
3923 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3925 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
3929 return (rtx) (HOST_WIDE_INT) 1;
3937 /* Write information about registers and basic blocks into FILE.
3938 This is part of making a debugging dump. */
3941 dump_regset (r, outf)
3948 fputs (" (nil)", outf);
3952 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
3954 fprintf (outf, " %d", i);
3955 if (i < FIRST_PSEUDO_REGISTER)
3956 fprintf (outf, " [%s]",
3961 /* Print a human-reaable representation of R on the standard error
3962 stream. This function is designed to be used from within the
3969 dump_regset (r, stderr);
3970 putc ('\n', stderr);
3973 /* Dump the rtl into the current debugging dump file, then abort. */
3976 print_rtl_and_abort_fcn (file, line, function)
3979 const char *function;
3983 print_rtl_with_bb (rtl_dump_file, get_insns ());
3984 fclose (rtl_dump_file);
3987 fancy_abort (file, line, function);
3990 /* Recompute register set/reference counts immediately prior to register
3993 This avoids problems with set/reference counts changing to/from values
3994 which have special meanings to the register allocators.
3996 Additionally, the reference counts are the primary component used by the
3997 register allocators to prioritize pseudos for allocation to hard regs.
3998 More accurate reference counts generally lead to better register allocation.
4000 F is the first insn to be scanned.
4002 LOOP_STEP denotes how much loop_depth should be incremented per
4003 loop nesting level in order to increase the ref count more for
4004 references in a loop.
4006 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4007 possibly other information which is used by the register allocators. */
4010 recompute_reg_usage (f, loop_step)
4011 rtx f ATTRIBUTE_UNUSED;
4012 int loop_step ATTRIBUTE_UNUSED;
4014 allocate_reg_life_data ();
4015 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4018 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4019 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4020 of the number of registers that died. */
4023 count_or_remove_death_notes (blocks, kill)
4029 for (i = n_basic_blocks - 1; i >= 0; --i)
4034 if (blocks && ! TEST_BIT (blocks, i))
4037 bb = BASIC_BLOCK (i);
4039 for (insn = bb->head;; insn = NEXT_INSN (insn))
4043 rtx *pprev = ®_NOTES (insn);
4048 switch (REG_NOTE_KIND (link))
4051 if (GET_CODE (XEXP (link, 0)) == REG)
4053 rtx reg = XEXP (link, 0);
4056 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4059 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4067 rtx next = XEXP (link, 1);
4068 free_EXPR_LIST_node (link);
4069 *pprev = link = next;
4075 pprev = &XEXP (link, 1);
4082 if (insn == bb->end)
4089 /* Clear LOG_LINKS fields of insns in a chain.
4090 Also clear the global_live_at_{start,end} fields of the basic block
4094 clear_log_links (insns)
4100 for (i = insns; i; i = NEXT_INSN (i))
4104 for (b = 0; b < n_basic_blocks; b++)
4106 basic_block bb = BASIC_BLOCK (b);
4108 bb->global_live_at_start = NULL;
4109 bb->global_live_at_end = NULL;
4112 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
4113 EXIT_BLOCK_PTR->global_live_at_start = NULL;
4116 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4117 correspond to the hard registers, if any, set in that map. This
4118 could be done far more efficiently by having all sorts of special-cases
4119 with moving single words, but probably isn't worth the trouble. */
4122 reg_set_to_hard_reg_set (to, from)
4128 EXECUTE_IF_SET_IN_BITMAP
4131 if (i >= FIRST_PSEUDO_REGISTER)
4133 SET_HARD_REG_BIT (*to, i);