* config/alpha/x-vms (USE_COLLECT2): Set to empty.
[official-gcc.git] / gcc / regrename.c
blob09856f828d5ec7ac65a1bddcb0ef575811d7e161
1 /* Register renaming for the GNU compiler.
2 Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
21 #define REG_OK_STRICT
23 #include "config.h"
24 #include "system.h"
25 #include "rtl.h"
26 #include "tm_p.h"
27 #include "insn-config.h"
28 #include "regs.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
31 #include "reload.h"
32 #include "output.h"
33 #include "function.h"
34 #include "recog.h"
35 #include "flags.h"
36 #include "toplev.h"
37 #include "obstack.h"
39 #define obstack_chunk_alloc xmalloc
40 #define obstack_chunk_free free
42 #ifndef REGNO_MODE_OK_FOR_BASE_P
43 #define REGNO_MODE_OK_FOR_BASE_P(REGNO, MODE) REGNO_OK_FOR_BASE_P (REGNO)
44 #endif
46 #ifndef REG_MODE_OK_FOR_BASE_P
47 #define REG_MODE_OK_FOR_BASE_P(REGNO, MODE) REG_OK_FOR_BASE_P (REGNO)
48 #endif
50 static const char *const reg_class_names[] = REG_CLASS_NAMES;
52 struct du_chain
54 struct du_chain *next_chain;
55 struct du_chain *next_use;
57 rtx insn;
58 rtx *loc;
59 enum reg_class class;
60 unsigned int need_caller_save_reg:1;
61 unsigned int earlyclobber:1;
64 enum scan_actions
66 terminate_all_read,
67 terminate_overlapping_read,
68 terminate_write,
69 terminate_dead,
70 mark_read,
71 mark_write
74 static const char * const scan_actions_name[] =
76 "terminate_all_read",
77 "terminate_overlapping_read",
78 "terminate_write",
79 "terminate_dead",
80 "mark_read",
81 "mark_write"
84 static struct obstack rename_obstack;
86 static void do_replace PARAMS ((struct du_chain *, int));
87 static void scan_rtx_reg PARAMS ((rtx, rtx *, enum reg_class,
88 enum scan_actions, enum op_type, int));
89 static void scan_rtx_address PARAMS ((rtx, rtx *, enum reg_class,
90 enum scan_actions, enum machine_mode));
91 static void scan_rtx PARAMS ((rtx, rtx *, enum reg_class,
92 enum scan_actions, enum op_type, int));
93 static struct du_chain *build_def_use PARAMS ((basic_block));
94 static void dump_def_use_chain PARAMS ((struct du_chain *));
95 static void note_sets PARAMS ((rtx, rtx, void *));
96 static void clear_dead_regs PARAMS ((HARD_REG_SET *, enum machine_mode, rtx));
97 static void merge_overlapping_regs PARAMS ((basic_block, HARD_REG_SET *,
98 struct du_chain *));
100 /* Called through note_stores from update_life. Find sets of registers, and
101 record them in *DATA (which is actually a HARD_REG_SET *). */
103 static void
104 note_sets (x, set, data)
105 rtx x;
106 rtx set ATTRIBUTE_UNUSED;
107 void *data;
109 HARD_REG_SET *pset = (HARD_REG_SET *) data;
110 unsigned int regno;
111 int nregs;
112 if (GET_CODE (x) != REG)
113 return;
114 regno = REGNO (x);
115 nregs = HARD_REGNO_NREGS (regno, GET_MODE (x));
117 /* There must not be pseudos at this point. */
118 if (regno + nregs > FIRST_PSEUDO_REGISTER)
119 abort ();
121 while (nregs-- > 0)
122 SET_HARD_REG_BIT (*pset, regno + nregs);
125 /* Clear all registers from *PSET for which a note of kind KIND can be found
126 in the list NOTES. */
128 static void
129 clear_dead_regs (pset, kind, notes)
130 HARD_REG_SET *pset;
131 enum machine_mode kind;
132 rtx notes;
134 rtx note;
135 for (note = notes; note; note = XEXP (note, 1))
136 if (REG_NOTE_KIND (note) == kind && REG_P (XEXP (note, 0)))
138 rtx reg = XEXP (note, 0);
139 unsigned int regno = REGNO (reg);
140 int nregs = HARD_REGNO_NREGS (regno, GET_MODE (reg));
142 /* There must not be pseudos at this point. */
143 if (regno + nregs > FIRST_PSEUDO_REGISTER)
144 abort ();
146 while (nregs-- > 0)
147 CLEAR_HARD_REG_BIT (*pset, regno + nregs);
151 /* For a def-use chain CHAIN in basic block B, find which registers overlap
152 its lifetime and set the corresponding bits in *PSET. */
154 static void
155 merge_overlapping_regs (b, pset, chain)
156 basic_block b;
157 HARD_REG_SET *pset;
158 struct du_chain *chain;
160 struct du_chain *t = chain;
161 rtx insn;
162 HARD_REG_SET live;
164 REG_SET_TO_HARD_REG_SET (live, b->global_live_at_start);
165 insn = b->head;
166 while (t)
168 /* Search forward until the next reference to the register to be
169 renamed. */
170 while (insn != t->insn)
172 if (INSN_P (insn))
174 clear_dead_regs (&live, REG_DEAD, REG_NOTES (insn));
175 note_stores (PATTERN (insn), note_sets, (void *) &live);
176 /* Only record currently live regs if we are inside the
177 reg's live range. */
178 if (t != chain)
179 IOR_HARD_REG_SET (*pset, live);
180 clear_dead_regs (&live, REG_UNUSED, REG_NOTES (insn));
182 insn = NEXT_INSN (insn);
185 IOR_HARD_REG_SET (*pset, live);
187 /* For the last reference, also merge in all registers set in the
188 same insn.
189 @@@ We only have take earlyclobbered sets into account. */
190 if (! t->next_use)
191 note_stores (PATTERN (insn), note_sets, (void *) pset);
193 t = t->next_use;
197 /* Perform register renaming on the current function. */
199 void
200 regrename_optimize ()
202 int tick[FIRST_PSEUDO_REGISTER];
203 int this_tick = 0;
204 int b;
205 char *first_obj;
207 memset (tick, 0, sizeof tick);
209 gcc_obstack_init (&rename_obstack);
210 first_obj = (char *) obstack_alloc (&rename_obstack, 0);
212 for (b = 0; b < n_basic_blocks; b++)
214 basic_block bb = BASIC_BLOCK (b);
215 struct du_chain *all_chains = 0;
216 HARD_REG_SET unavailable;
217 HARD_REG_SET regs_seen;
219 CLEAR_HARD_REG_SET (unavailable);
221 if (rtl_dump_file)
222 fprintf (rtl_dump_file, "\nBasic block %d:\n", b);
224 all_chains = build_def_use (bb);
226 if (rtl_dump_file)
227 dump_def_use_chain (all_chains);
229 CLEAR_HARD_REG_SET (unavailable);
230 /* Don't clobber traceback for noreturn functions. */
231 if (frame_pointer_needed)
233 int i;
235 for (i = HARD_REGNO_NREGS (FRAME_POINTER_REGNUM, Pmode); i--;)
236 SET_HARD_REG_BIT (unavailable, FRAME_POINTER_REGNUM + i);
238 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
239 for (i = HARD_REGNO_NREGS (HARD_FRAME_POINTER_REGNUM, Pmode); i--;)
240 SET_HARD_REG_BIT (unavailable, HARD_FRAME_POINTER_REGNUM + i);
241 #endif
244 CLEAR_HARD_REG_SET (regs_seen);
245 while (all_chains)
247 int new_reg, best_new_reg = -1;
248 int n_uses;
249 struct du_chain *this = all_chains;
250 struct du_chain *tmp, *last;
251 HARD_REG_SET this_unavailable;
252 int reg = REGNO (*this->loc);
253 int i;
255 all_chains = this->next_chain;
257 #if 0 /* This just disables optimization opportunities. */
258 /* Only rename once we've seen the reg more than once. */
259 if (! TEST_HARD_REG_BIT (regs_seen, reg))
261 SET_HARD_REG_BIT (regs_seen, reg);
262 continue;
264 #endif
266 if (fixed_regs[reg] || global_regs[reg]
267 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
268 || (frame_pointer_needed && reg == HARD_FRAME_POINTER_REGNUM)
269 #else
270 || (frame_pointer_needed && reg == FRAME_POINTER_REGNUM)
271 #endif
273 continue;
275 COPY_HARD_REG_SET (this_unavailable, unavailable);
277 /* Find last entry on chain (which has the need_caller_save bit),
278 count number of uses, and narrow the set of registers we can
279 use for renaming. */
280 n_uses = 0;
281 for (last = this; last->next_use; last = last->next_use)
283 n_uses++;
284 IOR_COMPL_HARD_REG_SET (this_unavailable,
285 reg_class_contents[last->class]);
287 if (n_uses < 1)
288 continue;
290 IOR_COMPL_HARD_REG_SET (this_unavailable,
291 reg_class_contents[last->class]);
293 if (this->need_caller_save_reg)
294 IOR_HARD_REG_SET (this_unavailable, call_used_reg_set);
296 merge_overlapping_regs (bb, &this_unavailable, this);
298 /* Now potential_regs is a reasonable approximation, let's
299 have a closer look at each register still in there. */
300 for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++)
302 int nregs = HARD_REGNO_NREGS (new_reg, GET_MODE (*this->loc));
304 for (i = nregs - 1; i >= 0; --i)
305 if (TEST_HARD_REG_BIT (this_unavailable, new_reg + i)
306 || fixed_regs[new_reg + i]
307 || global_regs[new_reg + i]
308 /* Can't use regs which aren't saved by the prologue. */
309 || (! regs_ever_live[new_reg + i]
310 && ! call_used_regs[new_reg + i])
311 #ifdef LEAF_REGISTERS
312 /* We can't use a non-leaf register if we're in a
313 leaf function. */
314 || (current_function_is_leaf
315 && !LEAF_REGISTERS[new_reg + i])
316 #endif
317 #ifdef HARD_REGNO_RENAME_OK
318 || ! HARD_REGNO_RENAME_OK (reg + i, new_reg + i)
319 #endif
321 break;
322 if (i >= 0)
323 continue;
325 /* See whether it accepts all modes that occur in
326 definition and uses. */
327 for (tmp = this; tmp; tmp = tmp->next_use)
328 if (! HARD_REGNO_MODE_OK (new_reg, GET_MODE (*tmp->loc)))
329 break;
330 if (! tmp)
332 if (best_new_reg == -1
333 || tick[best_new_reg] > tick[new_reg])
334 best_new_reg = new_reg;
338 if (rtl_dump_file)
340 fprintf (rtl_dump_file, "Register %s in insn %d",
341 reg_names[reg], INSN_UID (last->insn));
342 if (last->need_caller_save_reg)
343 fprintf (rtl_dump_file, " crosses a call");
346 if (best_new_reg == -1)
348 if (rtl_dump_file)
349 fprintf (rtl_dump_file, "; no available registers\n");
350 continue;
353 do_replace (this, best_new_reg);
354 tick[best_new_reg] = this_tick++;
356 if (rtl_dump_file)
357 fprintf (rtl_dump_file, ", renamed as %s\n", reg_names[best_new_reg]);
360 obstack_free (&rename_obstack, first_obj);
363 obstack_free (&rename_obstack, NULL);
365 if (rtl_dump_file)
366 fputc ('\n', rtl_dump_file);
368 count_or_remove_death_notes (NULL, 1);
369 update_life_info (NULL, UPDATE_LIFE_LOCAL,
370 PROP_REG_INFO | PROP_DEATH_NOTES);
373 static void
374 do_replace (chain, reg)
375 struct du_chain *chain;
376 int reg;
378 while (chain)
380 unsigned int regno = ORIGINAL_REGNO (*chain->loc);
381 *chain->loc = gen_raw_REG (GET_MODE (*chain->loc), reg);
382 if (regno >= FIRST_PSEUDO_REGISTER)
383 ORIGINAL_REGNO (*chain->loc) = regno;
384 chain = chain->next_use;
389 static struct du_chain *open_chains;
390 static struct du_chain *closed_chains;
392 static void
393 scan_rtx_reg (insn, loc, class, action, type, earlyclobber)
394 rtx insn;
395 rtx *loc;
396 enum reg_class class;
397 enum scan_actions action;
398 enum op_type type;
399 int earlyclobber;
401 struct du_chain **p;
402 rtx x = *loc;
403 enum machine_mode mode = GET_MODE (x);
404 int this_regno = REGNO (x);
405 int this_nregs = HARD_REGNO_NREGS (this_regno, mode);
407 if (action == mark_write)
409 if (type == OP_OUT)
411 struct du_chain *this = (struct du_chain *)
412 obstack_alloc (&rename_obstack, sizeof (struct du_chain));
413 this->next_use = 0;
414 this->next_chain = open_chains;
415 this->loc = loc;
416 this->insn = insn;
417 this->class = class;
418 this->need_caller_save_reg = 0;
419 this->earlyclobber = earlyclobber;
420 open_chains = this;
422 return;
425 if ((type == OP_OUT && action != terminate_write)
426 || (type != OP_OUT && action == terminate_write))
427 return;
429 for (p = &open_chains; *p;)
431 struct du_chain *this = *p;
433 /* Check if the chain has been terminated if it has then skip to
434 the next chain.
436 This can happen when we've already appended the location to
437 the chain in Step 3, but are trying to hide in-out operands
438 from terminate_write in Step 5. */
440 if (*this->loc == cc0_rtx)
441 p = &this->next_chain;
442 else
444 int regno = REGNO (*this->loc);
445 int nregs = HARD_REGNO_NREGS (regno, GET_MODE (*this->loc));
446 int exact_match = (regno == this_regno && nregs == this_nregs);
448 if (regno + nregs <= this_regno
449 || this_regno + this_nregs <= regno)
451 p = &this->next_chain;
452 continue;
455 if (action == mark_read)
457 if (! exact_match)
458 abort ();
460 /* ??? Class NO_REGS can happen if the md file makes use of
461 EXTRA_CONSTRAINTS to match registers. Which is arguably
462 wrong, but there we are. Since we know not what this may
463 be replaced with, terminate the chain. */
464 if (class != NO_REGS)
466 this = (struct du_chain *)
467 obstack_alloc (&rename_obstack, sizeof (struct du_chain));
468 this->next_use = 0;
469 this->next_chain = (*p)->next_chain;
470 this->loc = loc;
471 this->insn = insn;
472 this->class = class;
473 this->need_caller_save_reg = 0;
474 while (*p)
475 p = &(*p)->next_use;
476 *p = this;
477 return;
481 if (action != terminate_overlapping_read || ! exact_match)
483 struct du_chain *next = this->next_chain;
485 /* Whether the terminated chain can be used for renaming
486 depends on the action and this being an exact match.
487 In either case, we remove this element from open_chains. */
489 if ((action == terminate_dead || action == terminate_write)
490 && exact_match)
492 this->next_chain = closed_chains;
493 closed_chains = this;
494 if (rtl_dump_file)
495 fprintf (rtl_dump_file,
496 "Closing chain %s at insn %d (%s)\n",
497 reg_names[REGNO (*this->loc)], INSN_UID (insn),
498 scan_actions_name[(int) action]);
500 else
502 if (rtl_dump_file)
503 fprintf (rtl_dump_file,
504 "Discarding chain %s at insn %d (%s)\n",
505 reg_names[REGNO (*this->loc)], INSN_UID (insn),
506 scan_actions_name[(int) action]);
508 *p = next;
510 else
511 p = &this->next_chain;
516 /* Adapted from find_reloads_address_1. CLASS is INDEX_REG_CLASS or
517 BASE_REG_CLASS depending on how the register is being considered. */
519 static void
520 scan_rtx_address (insn, loc, class, action, mode)
521 rtx insn;
522 rtx *loc;
523 enum reg_class class;
524 enum scan_actions action;
525 enum machine_mode mode;
527 rtx x = *loc;
528 RTX_CODE code = GET_CODE (x);
529 const char *fmt;
530 int i, j;
532 if (action == mark_write)
533 return;
535 switch (code)
537 case PLUS:
539 rtx orig_op0 = XEXP (x, 0);
540 rtx orig_op1 = XEXP (x, 1);
541 RTX_CODE code0 = GET_CODE (orig_op0);
542 RTX_CODE code1 = GET_CODE (orig_op1);
543 rtx op0 = orig_op0;
544 rtx op1 = orig_op1;
545 rtx *locI = NULL;
546 rtx *locB = NULL;
548 if (GET_CODE (op0) == SUBREG)
550 op0 = SUBREG_REG (op0);
551 code0 = GET_CODE (op0);
554 if (GET_CODE (op1) == SUBREG)
556 op1 = SUBREG_REG (op1);
557 code1 = GET_CODE (op1);
560 if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE
561 || code0 == ZERO_EXTEND || code1 == MEM)
563 locI = &XEXP (x, 0);
564 locB = &XEXP (x, 1);
566 else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE
567 || code1 == ZERO_EXTEND || code0 == MEM)
569 locI = &XEXP (x, 1);
570 locB = &XEXP (x, 0);
572 else if (code0 == CONST_INT || code0 == CONST
573 || code0 == SYMBOL_REF || code0 == LABEL_REF)
574 locB = &XEXP (x, 1);
575 else if (code1 == CONST_INT || code1 == CONST
576 || code1 == SYMBOL_REF || code1 == LABEL_REF)
577 locB = &XEXP (x, 0);
578 else if (code0 == REG && code1 == REG)
580 int index_op;
582 if (REG_OK_FOR_INDEX_P (op0)
583 && REG_MODE_OK_FOR_BASE_P (op1, mode))
584 index_op = 0;
585 else if (REG_OK_FOR_INDEX_P (op1)
586 && REG_MODE_OK_FOR_BASE_P (op0, mode))
587 index_op = 1;
588 else if (REG_MODE_OK_FOR_BASE_P (op1, mode))
589 index_op = 0;
590 else if (REG_MODE_OK_FOR_BASE_P (op0, mode))
591 index_op = 1;
592 else if (REG_OK_FOR_INDEX_P (op1))
593 index_op = 1;
594 else
595 index_op = 0;
597 locI = &XEXP (x, index_op);
598 locB = &XEXP (x, !index_op);
600 else if (code0 == REG)
602 locI = &XEXP (x, 0);
603 locB = &XEXP (x, 1);
605 else if (code1 == REG)
607 locI = &XEXP (x, 1);
608 locB = &XEXP (x, 0);
611 if (locI)
612 scan_rtx_address (insn, locI, INDEX_REG_CLASS, action, mode);
613 if (locB)
614 scan_rtx_address (insn, locB, MODE_BASE_REG_CLASS (mode), action, mode);
615 return;
618 case POST_INC:
619 case POST_DEC:
620 case POST_MODIFY:
621 case PRE_INC:
622 case PRE_DEC:
623 case PRE_MODIFY:
624 #ifndef AUTO_INC_DEC
625 /* If the target doesn't claim to handle autoinc, this must be
626 something special, like a stack push. Kill this chain. */
627 action = terminate_all_read;
628 #endif
629 break;
631 case MEM:
632 scan_rtx_address (insn, &XEXP (x, 0),
633 MODE_BASE_REG_CLASS (GET_MODE (x)), action,
634 GET_MODE (x));
635 return;
637 case REG:
638 scan_rtx_reg (insn, loc, class, action, OP_IN, 0);
639 return;
641 default:
642 break;
645 fmt = GET_RTX_FORMAT (code);
646 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
648 if (fmt[i] == 'e')
649 scan_rtx_address (insn, &XEXP (x, i), class, action, mode);
650 else if (fmt[i] == 'E')
651 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
652 scan_rtx_address (insn, &XVECEXP (x, i, j), class, action, mode);
656 static void
657 scan_rtx (insn, loc, class, action, type, earlyclobber)
658 rtx insn;
659 rtx *loc;
660 enum reg_class class;
661 enum scan_actions action;
662 enum op_type type;
663 int earlyclobber;
665 const char *fmt;
666 rtx x = *loc;
667 enum rtx_code code = GET_CODE (x);
668 int i, j;
670 code = GET_CODE (x);
671 switch (code)
673 case CONST:
674 case CONST_INT:
675 case CONST_DOUBLE:
676 case SYMBOL_REF:
677 case LABEL_REF:
678 case CC0:
679 case PC:
680 return;
682 case REG:
683 scan_rtx_reg (insn, loc, class, action, type, earlyclobber);
684 return;
686 case MEM:
687 scan_rtx_address (insn, &XEXP (x, 0),
688 MODE_BASE_REG_CLASS (GET_MODE (x)), action,
689 GET_MODE (x));
690 return;
692 case SET:
693 scan_rtx (insn, &SET_SRC (x), class, action, OP_IN, 0);
694 scan_rtx (insn, &SET_DEST (x), class, action, OP_OUT, 0);
695 return;
697 case STRICT_LOW_PART:
698 scan_rtx (insn, &XEXP (x, 0), class, action, OP_INOUT, earlyclobber);
699 return;
701 case ZERO_EXTRACT:
702 case SIGN_EXTRACT:
703 scan_rtx (insn, &XEXP (x, 0), class, action,
704 type == OP_IN ? OP_IN : OP_INOUT, earlyclobber);
705 scan_rtx (insn, &XEXP (x, 1), class, action, OP_IN, 0);
706 scan_rtx (insn, &XEXP (x, 2), class, action, OP_IN, 0);
707 return;
709 case POST_INC:
710 case PRE_INC:
711 case POST_DEC:
712 case PRE_DEC:
713 case POST_MODIFY:
714 case PRE_MODIFY:
715 /* Should only happen inside MEM. */
716 abort ();
718 case CLOBBER:
719 scan_rtx (insn, &SET_DEST (x), class, action, OP_OUT, 1);
720 return;
722 case EXPR_LIST:
723 scan_rtx (insn, &XEXP (x, 0), class, action, type, 0);
724 if (XEXP (x, 1))
725 scan_rtx (insn, &XEXP (x, 1), class, action, type, 0);
726 return;
728 default:
729 break;
732 fmt = GET_RTX_FORMAT (code);
733 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
735 if (fmt[i] == 'e')
736 scan_rtx (insn, &XEXP (x, i), class, action, type, 0);
737 else if (fmt[i] == 'E')
738 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
739 scan_rtx (insn, &XVECEXP (x, i, j), class, action, type, 0);
743 /* Build def/use chain */
745 static struct du_chain *
746 build_def_use (bb)
747 basic_block bb;
749 rtx insn;
751 open_chains = closed_chains = NULL;
753 for (insn = bb->head; ; insn = NEXT_INSN (insn))
755 if (INSN_P (insn))
757 int n_ops;
758 rtx note;
759 rtx old_operands[MAX_RECOG_OPERANDS];
760 rtx old_dups[MAX_DUP_OPERANDS];
761 int i;
762 int alt;
763 int predicated;
765 /* Process the insn, determining its effect on the def-use
766 chains. We perform the following steps with the register
767 references in the insn:
768 (1) Any read that overlaps an open chain, but doesn't exactly
769 match, causes that chain to be closed. We can't deal
770 with overlaps yet.
771 (2) Any read outside an operand causes any chain it overlaps
772 with to be closed, since we can't replace it.
773 (3) Any read inside an operand is added if there's already
774 an open chain for it.
775 (4) For any REG_DEAD note we find, close open chains that
776 overlap it.
777 (5) For any write we find, close open chains that overlap it.
778 (6) For any write we find in an operand, make a new chain.
779 (7) For any REG_UNUSED, close any chains we just opened. */
781 extract_insn (insn);
782 constrain_operands (1);
783 preprocess_constraints ();
784 alt = which_alternative;
785 n_ops = recog_data.n_operands;
787 /* Simplify the code below by rewriting things to reflect
788 matching constraints. Also promote OP_OUT to OP_INOUT
789 in predicated instructions. */
791 predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
792 for (i = 0; i < n_ops; ++i)
794 int matches = recog_op_alt[i][alt].matches;
795 if (matches >= 0)
796 recog_op_alt[i][alt].class = recog_op_alt[matches][alt].class;
797 if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
798 || (predicated && recog_data.operand_type[i] == OP_OUT))
799 recog_data.operand_type[i] = OP_INOUT;
802 /* Step 1: Close chains for which we have overlapping reads. */
803 for (i = 0; i < n_ops; i++)
804 scan_rtx (insn, recog_data.operand_loc[i],
805 NO_REGS, terminate_overlapping_read,
806 recog_data.operand_type[i], 0);
808 /* Step 2: Close chains for which we have reads outside operands.
809 We do this by munging all operands into CC0, and closing
810 everything remaining. */
812 for (i = 0; i < n_ops; i++)
814 old_operands[i] = recog_data.operand[i];
815 /* Don't squash match_operator or match_parallel here, since
816 we don't know that all of the contained registers are
817 reachable by proper operands. */
818 if (recog_data.constraints[i][0] == '\0')
819 continue;
820 *recog_data.operand_loc[i] = cc0_rtx;
822 for (i = 0; i < recog_data.n_dups; i++)
824 old_dups[i] = *recog_data.dup_loc[i];
825 *recog_data.dup_loc[i] = cc0_rtx;
828 scan_rtx (insn, &PATTERN (insn), NO_REGS, terminate_all_read,
829 OP_IN, 0);
831 for (i = 0; i < recog_data.n_dups; i++)
832 *recog_data.dup_loc[i] = old_dups[i];
833 for (i = 0; i < n_ops; i++)
834 *recog_data.operand_loc[i] = old_operands[i];
836 /* Step 2B: Can't rename function call argument registers. */
837 if (GET_CODE (insn) == CALL_INSN && CALL_INSN_FUNCTION_USAGE (insn))
838 scan_rtx (insn, &CALL_INSN_FUNCTION_USAGE (insn),
839 NO_REGS, terminate_all_read, OP_IN, 0);
841 /* Step 2C: Can't rename asm operands that were originally
842 hard registers. */
843 if (asm_noperands (PATTERN (insn)) > 0)
844 for (i = 0; i < n_ops; i++)
846 rtx *loc = recog_data.operand_loc[i];
847 rtx op = *loc;
849 if (GET_CODE (op) == REG
850 && REGNO (op) == ORIGINAL_REGNO (op)
851 && (recog_data.operand_type[i] == OP_IN
852 || recog_data.operand_type[i] == OP_INOUT))
853 scan_rtx (insn, loc, NO_REGS, terminate_all_read, OP_IN, 0);
856 /* Step 3: Append to chains for reads inside operands. */
857 for (i = 0; i < n_ops + recog_data.n_dups; i++)
859 int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops];
860 rtx *loc = (i < n_ops
861 ? recog_data.operand_loc[opn]
862 : recog_data.dup_loc[i - n_ops]);
863 enum reg_class class = recog_op_alt[opn][alt].class;
864 enum op_type type = recog_data.operand_type[opn];
866 /* Don't scan match_operand here, since we've no reg class
867 information to pass down. Any operands that we could
868 substitute in will be represented elsewhere. */
869 if (recog_data.constraints[opn][0] == '\0')
870 continue;
872 if (recog_op_alt[opn][alt].is_address)
873 scan_rtx_address (insn, loc, class, mark_read, VOIDmode);
874 else
875 scan_rtx (insn, loc, class, mark_read, type, 0);
878 /* Step 4: Close chains for registers that die here.
879 Also record updates for REG_INC notes. */
880 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
882 if (REG_NOTE_KIND (note) == REG_DEAD)
883 scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead,
884 OP_IN, 0);
885 else if (REG_NOTE_KIND (note) == REG_INC)
886 scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_read,
887 OP_INOUT, 0);
890 /* Step 4B: If this is a call, any chain live at this point
891 requires a caller-saved reg. */
892 if (GET_CODE (insn) == CALL_INSN)
894 struct du_chain *p;
895 for (p = open_chains; p; p = p->next_chain)
896 p->need_caller_save_reg = 1;
899 /* Step 5: Close open chains that overlap writes. Similar to
900 step 2, we hide in-out operands, since we do not want to
901 close these chains. */
903 for (i = 0; i < n_ops; i++)
905 old_operands[i] = recog_data.operand[i];
906 if (recog_data.operand_type[i] == OP_INOUT)
907 *recog_data.operand_loc[i] = cc0_rtx;
909 for (i = 0; i < recog_data.n_dups; i++)
911 int opn = recog_data.dup_num[i];
912 old_dups[i] = *recog_data.dup_loc[i];
913 if (recog_data.operand_type[opn] == OP_INOUT)
914 *recog_data.dup_loc[i] = cc0_rtx;
917 scan_rtx (insn, &PATTERN (insn), NO_REGS, terminate_write, OP_IN, 0);
919 for (i = 0; i < recog_data.n_dups; i++)
920 *recog_data.dup_loc[i] = old_dups[i];
921 for (i = 0; i < n_ops; i++)
922 *recog_data.operand_loc[i] = old_operands[i];
924 /* Step 6: Begin new chains for writes inside operands. */
925 /* ??? Many targets have output constraints on the SET_DEST
926 of a call insn, which is stupid, since these are certainly
927 ABI defined hard registers. Don't change calls at all.
928 Similarly take special care for asm statement that originally
929 referenced hard registers. */
930 if (asm_noperands (PATTERN (insn)) > 0)
932 for (i = 0; i < n_ops; i++)
933 if (recog_data.operand_type[i] == OP_OUT)
935 rtx *loc = recog_data.operand_loc[i];
936 rtx op = *loc;
937 enum reg_class class = recog_op_alt[i][alt].class;
939 if (GET_CODE (op) == REG
940 && REGNO (op) == ORIGINAL_REGNO (op))
941 continue;
943 scan_rtx (insn, loc, class, mark_write, OP_OUT,
944 recog_op_alt[i][alt].earlyclobber);
947 else if (GET_CODE (insn) != CALL_INSN)
948 for (i = 0; i < n_ops + recog_data.n_dups; i++)
950 int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops];
951 rtx *loc = (i < n_ops
952 ? recog_data.operand_loc[opn]
953 : recog_data.dup_loc[i - n_ops]);
954 enum reg_class class = recog_op_alt[opn][alt].class;
956 if (recog_data.operand_type[opn] == OP_OUT)
957 scan_rtx (insn, loc, class, mark_write, OP_OUT,
958 recog_op_alt[opn][alt].earlyclobber);
961 /* Step 7: Close chains for registers that were never
962 really used here. */
963 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
964 if (REG_NOTE_KIND (note) == REG_UNUSED)
965 scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead,
966 OP_IN, 0);
968 if (insn == bb->end)
969 break;
972 /* Since we close every chain when we find a REG_DEAD note, anything that
973 is still open lives past the basic block, so it can't be renamed. */
974 return closed_chains;
977 /* Dump all def/use chains in CHAINS to RTL_DUMP_FILE. They are
978 printed in reverse order as that's how we build them. */
980 static void
981 dump_def_use_chain (chains)
982 struct du_chain *chains;
984 while (chains)
986 struct du_chain *this = chains;
987 int r = REGNO (*this->loc);
988 int nregs = HARD_REGNO_NREGS (r, GET_MODE (*this->loc));
989 fprintf (rtl_dump_file, "Register %s (%d):", reg_names[r], nregs);
990 while (this)
992 fprintf (rtl_dump_file, " %d [%s]", INSN_UID (this->insn),
993 reg_class_names[this->class]);
994 this = this->next_use;
996 fprintf (rtl_dump_file, "\n");
997 chains = chains->next_chain;
1001 /* The following code does forward propagation of hard register copies.
1002 The object is to eliminate as many dependencies as possible, so that
1003 we have the most scheduling freedom. As a side effect, we also clean
1004 up some silly register allocation decisions made by reload. This
1005 code may be obsoleted by a new register allocator. */
1007 /* For each register, we have a list of registers that contain the same
1008 value. The OLDEST_REGNO field points to the head of the list, and
1009 the NEXT_REGNO field runs through the list. The MODE field indicates
1010 what mode the data is known to be in; this field is VOIDmode when the
1011 register is not known to contain valid data. */
1013 struct value_data_entry
1015 enum machine_mode mode;
1016 unsigned int oldest_regno;
1017 unsigned int next_regno;
1020 struct value_data
1022 struct value_data_entry e[FIRST_PSEUDO_REGISTER];
1023 unsigned int max_value_regs;
1026 static void kill_value_regno PARAMS ((unsigned, struct value_data *));
1027 static void kill_value PARAMS ((rtx, struct value_data *));
1028 static void set_value_regno PARAMS ((unsigned, enum machine_mode,
1029 struct value_data *));
1030 static void init_value_data PARAMS ((struct value_data *));
1031 static void kill_clobbered_value PARAMS ((rtx, rtx, void *));
1032 static void kill_set_value PARAMS ((rtx, rtx, void *));
1033 static int kill_autoinc_value PARAMS ((rtx *, void *));
1034 static void copy_value PARAMS ((rtx, rtx, struct value_data *));
1035 static bool mode_change_ok PARAMS ((enum machine_mode, enum machine_mode,
1036 unsigned int));
1037 static rtx find_oldest_value_reg PARAMS ((enum reg_class, rtx,
1038 struct value_data *));
1039 static bool replace_oldest_value_reg PARAMS ((rtx *, enum reg_class, rtx,
1040 struct value_data *));
1041 static bool replace_oldest_value_addr PARAMS ((rtx *, enum reg_class,
1042 enum machine_mode, rtx,
1043 struct value_data *));
1044 static bool replace_oldest_value_mem PARAMS ((rtx, rtx, struct value_data *));
1045 static bool copyprop_hardreg_forward_1 PARAMS ((basic_block,
1046 struct value_data *));
1047 extern void debug_value_data PARAMS ((struct value_data *));
1048 #ifdef ENABLE_CHECKING
1049 static void validate_value_data PARAMS ((struct value_data *));
1050 #endif
1052 /* Kill register REGNO. This involves removing it from any value lists,
1053 and resetting the value mode to VOIDmode. */
1055 static void
1056 kill_value_regno (regno, vd)
1057 unsigned int regno;
1058 struct value_data *vd;
1060 unsigned int i, next;
1062 if (vd->e[regno].oldest_regno != regno)
1064 for (i = vd->e[regno].oldest_regno;
1065 vd->e[i].next_regno != regno;
1066 i = vd->e[i].next_regno)
1067 continue;
1068 vd->e[i].next_regno = vd->e[regno].next_regno;
1070 else if ((next = vd->e[regno].next_regno) != INVALID_REGNUM)
1072 for (i = next; i != INVALID_REGNUM; i = vd->e[i].next_regno)
1073 vd->e[i].oldest_regno = next;
1076 vd->e[regno].mode = VOIDmode;
1077 vd->e[regno].oldest_regno = regno;
1078 vd->e[regno].next_regno = INVALID_REGNUM;
1080 #ifdef ENABLE_CHECKING
1081 validate_value_data (vd);
1082 #endif
1085 /* Kill X. This is a convenience function for kill_value_regno
1086 so that we mind the mode the register is in. */
1088 static void
1089 kill_value (x, vd)
1090 rtx x;
1091 struct value_data *vd;
1093 if (REG_P (x))
1095 unsigned int regno = REGNO (x);
1096 unsigned int n = HARD_REGNO_NREGS (regno, GET_MODE (x));
1097 unsigned int i, j;
1099 /* Kill the value we're told to kill. */
1100 for (i = 0; i < n; ++i)
1101 kill_value_regno (regno + i, vd);
1103 /* Kill everything that overlapped what we're told to kill. */
1104 if (regno < vd->max_value_regs)
1105 j = 0;
1106 else
1107 j = regno - vd->max_value_regs;
1108 for (; j < regno; ++j)
1110 if (vd->e[j].mode == VOIDmode)
1111 continue;
1112 n = HARD_REGNO_NREGS (regno, vd->e[j].mode);
1113 if (j + n > regno)
1114 for (i = 0; i < n; ++i)
1115 kill_value_regno (j + i, vd);
1120 /* Remember that REGNO is valid in MODE. */
1122 static void
1123 set_value_regno (regno, mode, vd)
1124 unsigned int regno;
1125 enum machine_mode mode;
1126 struct value_data *vd;
1128 unsigned int nregs;
1130 vd->e[regno].mode = mode;
1132 nregs = HARD_REGNO_NREGS (regno, mode);
1133 if (nregs > vd->max_value_regs)
1134 vd->max_value_regs = nregs;
1137 /* Initialize VD such that there are no known relationships between regs. */
1139 static void
1140 init_value_data (vd)
1141 struct value_data *vd;
1143 int i;
1144 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1146 vd->e[i].mode = VOIDmode;
1147 vd->e[i].oldest_regno = i;
1148 vd->e[i].next_regno = INVALID_REGNUM;
1150 vd->max_value_regs = 0;
1153 /* Called through note_stores. If X is clobbered, kill its value. */
1155 static void
1156 kill_clobbered_value (x, set, data)
1157 rtx x;
1158 rtx set;
1159 void *data;
1161 struct value_data *vd = data;
1162 if (GET_CODE (set) == CLOBBER)
1163 kill_value (x, vd);
1166 /* Called through note_stores. If X is set, not clobbered, kill its
1167 current value and install it as the root of its own value list. */
1169 static void
1170 kill_set_value (x, set, data)
1171 rtx x;
1172 rtx set;
1173 void *data;
1175 struct value_data *vd = data;
1176 if (GET_CODE (set) != CLOBBER && REG_P (x))
1178 kill_value (x, vd);
1179 set_value_regno (REGNO (x), GET_MODE (x), vd);
1183 /* Called through for_each_rtx. Kill any register used as the base of an
1184 auto-increment expression, and install that register as the root of its
1185 own value list. */
1187 static int
1188 kill_autoinc_value (px, data)
1189 rtx *px;
1190 void *data;
1192 rtx x = *px;
1193 struct value_data *vd = data;
1195 if (GET_RTX_CLASS (GET_CODE (x)) == 'a')
1197 x = XEXP (x, 0);
1198 kill_value (x, vd);
1199 set_value_regno (REGNO (x), Pmode, vd);
1200 return -1;
1203 return 0;
1206 /* Assert that SRC has been copied to DEST. Adjust the data structures
1207 to reflect that SRC contains an older copy of the shared value. */
1209 static void
1210 copy_value (dest, src, vd)
1211 rtx dest;
1212 rtx src;
1213 struct value_data *vd;
1215 unsigned int dr = REGNO (dest);
1216 unsigned int sr = REGNO (src);
1217 unsigned int dn, sn;
1218 unsigned int i;
1220 /* ??? At present, it's possible to see noop sets. It'd be nice if
1221 this were cleaned up beforehand... */
1222 if (sr == dr)
1223 return;
1225 /* Do not propagate copies to the stack pointer, as that can leave
1226 memory accesses with no scheduling dependancy on the stack update. */
1227 if (dr == STACK_POINTER_REGNUM)
1228 return;
1230 /* Likewise with the frame pointer, if we're using one. */
1231 if (frame_pointer_needed && dr == HARD_FRAME_POINTER_REGNUM)
1232 return;
1234 /* If SRC and DEST overlap, don't record anything. */
1235 dn = HARD_REGNO_NREGS (dr, GET_MODE (dest));
1236 sn = HARD_REGNO_NREGS (sr, GET_MODE (dest));
1237 if ((dr > sr && dr < sr + sn)
1238 || (sr > dr && sr < dr + dn))
1239 return;
1241 /* If SRC had no assigned mode (i.e. we didn't know it was live)
1242 assign it now and assume the value came from an input argument
1243 or somesuch. */
1244 if (vd->e[sr].mode == VOIDmode)
1245 set_value_regno (sr, vd->e[dr].mode, vd);
1247 /* If SRC had been assigned a mode narrower than the copy, we can't
1248 link DEST into the chain, because not all of the pieces of the
1249 copy came from oldest_regno. */
1250 else if (sn > (unsigned int) HARD_REGNO_NREGS (sr, vd->e[sr].mode))
1251 return;
1253 /* Link DR at the end of the value chain used by SR. */
1255 vd->e[dr].oldest_regno = vd->e[sr].oldest_regno;
1257 for (i = sr; vd->e[i].next_regno != INVALID_REGNUM; i = vd->e[i].next_regno)
1258 continue;
1259 vd->e[i].next_regno = dr;
1261 #ifdef ENABLE_CHECKING
1262 validate_value_data (vd);
1263 #endif
1266 /* Return true if a mode change from ORIG to NEW is allowed for REGNO. */
1268 static bool
1269 mode_change_ok (orig_mode, new_mode, regno)
1270 enum machine_mode orig_mode, new_mode;
1271 unsigned int regno ATTRIBUTE_UNUSED;
1273 if (GET_MODE_SIZE (orig_mode) < GET_MODE_SIZE (new_mode))
1274 return false;
1276 #ifdef CLASS_CANNOT_CHANGE_MODE
1277 if (TEST_HARD_REG_BIT (reg_class_contents[CLASS_CANNOT_CHANGE_MODE], regno)
1278 && CLASS_CANNOT_CHANGE_MODE_P (orig_mode, new_mode))
1279 return false;
1280 #endif
1282 return true;
1285 /* Find the oldest copy of the value contained in REGNO that is in
1286 register class CLASS and has mode MODE. If found, return an rtx
1287 of that oldest register, otherwise return NULL. */
1289 static rtx
1290 find_oldest_value_reg (class, reg, vd)
1291 enum reg_class class;
1292 rtx reg;
1293 struct value_data *vd;
1295 unsigned int regno = REGNO (reg);
1296 enum machine_mode mode = GET_MODE (reg);
1297 unsigned int i;
1299 /* If we are accessing REG in some mode other that what we set it in,
1300 make sure that the replacement is valid. In particular, consider
1301 (set (reg:DI r11) (...))
1302 (set (reg:SI r9) (reg:SI r11))
1303 (set (reg:SI r10) (...))
1304 (set (...) (reg:DI r9))
1305 Replacing r9 with r11 is invalid. */
1306 if (mode != vd->e[regno].mode)
1308 if (HARD_REGNO_NREGS (regno, mode)
1309 > HARD_REGNO_NREGS (regno, vd->e[regno].mode))
1310 return NULL_RTX;
1313 for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno)
1314 if (TEST_HARD_REG_BIT (reg_class_contents[class], i)
1315 && (vd->e[i].mode == mode
1316 || mode_change_ok (vd->e[i].mode, mode, i)))
1318 rtx new = gen_rtx_raw_REG (mode, i);
1319 ORIGINAL_REGNO (new) = ORIGINAL_REGNO (reg);
1320 return new;
1323 return NULL_RTX;
1326 /* If possible, replace the register at *LOC with the oldest register
1327 in register class CLASS. Return true if successfully replaced. */
1329 static bool
1330 replace_oldest_value_reg (loc, class, insn, vd)
1331 rtx *loc;
1332 enum reg_class class;
1333 rtx insn;
1334 struct value_data *vd;
1336 rtx new = find_oldest_value_reg (class, *loc, vd);
1337 if (new)
1339 if (rtl_dump_file)
1340 fprintf (rtl_dump_file, "insn %u: replaced reg %u with %u\n",
1341 INSN_UID (insn), REGNO (*loc), REGNO (new));
1343 *loc = new;
1344 return true;
1346 return false;
1349 /* Similar to replace_oldest_value_reg, but *LOC contains an address.
1350 Adapted from find_reloads_address_1. CLASS is INDEX_REG_CLASS or
1351 BASE_REG_CLASS depending on how the register is being considered. */
1353 static bool
1354 replace_oldest_value_addr (loc, class, mode, insn, vd)
1355 rtx *loc;
1356 enum reg_class class;
1357 enum machine_mode mode;
1358 rtx insn;
1359 struct value_data *vd;
1361 rtx x = *loc;
1362 RTX_CODE code = GET_CODE (x);
1363 const char *fmt;
1364 int i, j;
1365 bool changed = false;
1367 switch (code)
1369 case PLUS:
1371 rtx orig_op0 = XEXP (x, 0);
1372 rtx orig_op1 = XEXP (x, 1);
1373 RTX_CODE code0 = GET_CODE (orig_op0);
1374 RTX_CODE code1 = GET_CODE (orig_op1);
1375 rtx op0 = orig_op0;
1376 rtx op1 = orig_op1;
1377 rtx *locI = NULL;
1378 rtx *locB = NULL;
1380 if (GET_CODE (op0) == SUBREG)
1382 op0 = SUBREG_REG (op0);
1383 code0 = GET_CODE (op0);
1386 if (GET_CODE (op1) == SUBREG)
1388 op1 = SUBREG_REG (op1);
1389 code1 = GET_CODE (op1);
1392 if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE
1393 || code0 == ZERO_EXTEND || code1 == MEM)
1395 locI = &XEXP (x, 0);
1396 locB = &XEXP (x, 1);
1398 else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE
1399 || code1 == ZERO_EXTEND || code0 == MEM)
1401 locI = &XEXP (x, 1);
1402 locB = &XEXP (x, 0);
1404 else if (code0 == CONST_INT || code0 == CONST
1405 || code0 == SYMBOL_REF || code0 == LABEL_REF)
1406 locB = &XEXP (x, 1);
1407 else if (code1 == CONST_INT || code1 == CONST
1408 || code1 == SYMBOL_REF || code1 == LABEL_REF)
1409 locB = &XEXP (x, 0);
1410 else if (code0 == REG && code1 == REG)
1412 int index_op;
1414 if (REG_OK_FOR_INDEX_P (op0)
1415 && REG_MODE_OK_FOR_BASE_P (op1, mode))
1416 index_op = 0;
1417 else if (REG_OK_FOR_INDEX_P (op1)
1418 && REG_MODE_OK_FOR_BASE_P (op0, mode))
1419 index_op = 1;
1420 else if (REG_MODE_OK_FOR_BASE_P (op1, mode))
1421 index_op = 0;
1422 else if (REG_MODE_OK_FOR_BASE_P (op0, mode))
1423 index_op = 1;
1424 else if (REG_OK_FOR_INDEX_P (op1))
1425 index_op = 1;
1426 else
1427 index_op = 0;
1429 locI = &XEXP (x, index_op);
1430 locB = &XEXP (x, !index_op);
1432 else if (code0 == REG)
1434 locI = &XEXP (x, 0);
1435 locB = &XEXP (x, 1);
1437 else if (code1 == REG)
1439 locI = &XEXP (x, 1);
1440 locB = &XEXP (x, 0);
1443 if (locI)
1444 changed |= replace_oldest_value_addr (locI, INDEX_REG_CLASS, mode,
1445 insn, vd);
1446 if (locB)
1447 changed |= replace_oldest_value_addr (locB,
1448 MODE_BASE_REG_CLASS (mode),
1449 mode, insn, vd);
1450 return changed;
1453 case POST_INC:
1454 case POST_DEC:
1455 case POST_MODIFY:
1456 case PRE_INC:
1457 case PRE_DEC:
1458 case PRE_MODIFY:
1459 return false;
1461 case MEM:
1462 return replace_oldest_value_mem (x, insn, vd);
1464 case REG:
1465 return replace_oldest_value_reg (loc, class, insn, vd);
1467 default:
1468 break;
1471 fmt = GET_RTX_FORMAT (code);
1472 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1474 if (fmt[i] == 'e')
1475 changed |= replace_oldest_value_addr (&XEXP (x, i), class, mode,
1476 insn, vd);
1477 else if (fmt[i] == 'E')
1478 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1479 changed |= replace_oldest_value_addr (&XVECEXP (x, i, j), class,
1480 mode, insn, vd);
1483 return changed;
1486 /* Similar to replace_oldest_value_reg, but X contains a memory. */
1488 static bool
1489 replace_oldest_value_mem (x, insn, vd)
1490 rtx x;
1491 rtx insn;
1492 struct value_data *vd;
1494 return replace_oldest_value_addr (&XEXP (x, 0),
1495 MODE_BASE_REG_CLASS (GET_MODE (x)),
1496 GET_MODE (x), insn, vd);
1499 /* Perform the forward copy propagation on basic block BB. */
1501 static bool
1502 copyprop_hardreg_forward_1 (bb, vd)
1503 basic_block bb;
1504 struct value_data *vd;
1506 bool changed = false;
1507 rtx insn;
1509 for (insn = bb->head; ; insn = NEXT_INSN (insn))
1511 int n_ops, i, alt, predicated;
1512 bool is_asm;
1513 rtx set;
1515 if (! INSN_P (insn))
1517 if (insn == bb->end)
1518 break;
1519 else
1520 continue;
1523 set = single_set (insn);
1524 extract_insn (insn);
1525 constrain_operands (1);
1526 preprocess_constraints ();
1527 alt = which_alternative;
1528 n_ops = recog_data.n_operands;
1529 is_asm = asm_noperands (PATTERN (insn)) >= 0;
1531 /* Simplify the code below by rewriting things to reflect
1532 matching constraints. Also promote OP_OUT to OP_INOUT
1533 in predicated instructions. */
1535 predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
1536 for (i = 0; i < n_ops; ++i)
1538 int matches = recog_op_alt[i][alt].matches;
1539 if (matches >= 0)
1540 recog_op_alt[i][alt].class = recog_op_alt[matches][alt].class;
1541 if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
1542 || (predicated && recog_data.operand_type[i] == OP_OUT))
1543 recog_data.operand_type[i] = OP_INOUT;
1546 /* For each earlyclobber operand, zap the value data. */
1547 for (i = 0; i < n_ops; i++)
1548 if (recog_op_alt[i][alt].earlyclobber)
1549 kill_value (recog_data.operand[i], vd);
1551 /* Within asms, a clobber cannot overlap inputs or outputs.
1552 I wouldn't think this were true for regular insns, but
1553 scan_rtx treats them like that... */
1554 note_stores (PATTERN (insn), kill_clobbered_value, vd);
1556 /* Kill all auto-incremented values. */
1557 /* ??? REG_INC is useless, since stack pushes aren't done that way. */
1558 for_each_rtx (&PATTERN (insn), kill_autoinc_value, vd);
1560 /* Kill all early-clobbered operands. */
1561 for (i = 0; i < n_ops; i++)
1562 if (recog_op_alt[i][alt].earlyclobber)
1563 kill_value (recog_data.operand[i], vd);
1565 /* Special-case plain move instructions, since we may well
1566 be able to do the move from a different register class. */
1567 if (set && REG_P (SET_SRC (set)))
1569 rtx src = SET_SRC (set);
1570 unsigned int regno = REGNO (src);
1571 enum machine_mode mode = GET_MODE (src);
1572 unsigned int i;
1573 rtx new;
1575 /* If we are accessing SRC in some mode other that what we
1576 set it in, make sure that the replacement is valid. */
1577 if (mode != vd->e[regno].mode)
1579 if (HARD_REGNO_NREGS (regno, mode)
1580 > HARD_REGNO_NREGS (regno, vd->e[regno].mode))
1581 goto no_move_special_case;
1584 /* If the destination is also a register, try to find a source
1585 register in the same class. */
1586 if (REG_P (SET_DEST (set)))
1588 new = find_oldest_value_reg (REGNO_REG_CLASS (regno), src, vd);
1589 if (new && validate_change (insn, &SET_SRC (set), new, 0))
1591 if (rtl_dump_file)
1592 fprintf (rtl_dump_file,
1593 "insn %u: replaced reg %u with %u\n",
1594 INSN_UID (insn), regno, REGNO (new));
1595 changed = true;
1596 goto did_replacement;
1600 /* Otherwise, try all valid registers and see if its valid. */
1601 for (i = vd->e[regno].oldest_regno; i != regno;
1602 i = vd->e[i].next_regno)
1603 if (vd->e[i].mode == mode
1604 || mode_change_ok (vd->e[i].mode, mode, i))
1606 new = gen_rtx_raw_REG (mode, i);
1607 if (validate_change (insn, &SET_SRC (set), new, 0))
1609 ORIGINAL_REGNO (new) = ORIGINAL_REGNO (src);
1610 if (rtl_dump_file)
1611 fprintf (rtl_dump_file,
1612 "insn %u: replaced reg %u with %u\n",
1613 INSN_UID (insn), regno, REGNO (new));
1614 changed = true;
1615 goto did_replacement;
1619 no_move_special_case:
1621 /* For each input operand, replace a hard register with the
1622 eldest live copy that's in an appropriate register class. */
1623 for (i = 0; i < n_ops; i++)
1625 bool replaced = false;
1627 /* Don't scan match_operand here, since we've no reg class
1628 information to pass down. Any operands that we could
1629 substitute in will be represented elsewhere. */
1630 if (recog_data.constraints[i][0] == '\0')
1631 continue;
1633 /* Don't replace in asms intentionally referencing hard regs. */
1634 if (is_asm && GET_CODE (recog_data.operand[i]) == REG
1635 && (REGNO (recog_data.operand[i])
1636 == ORIGINAL_REGNO (recog_data.operand[i])))
1637 continue;
1639 if (recog_data.operand_type[i] == OP_IN)
1641 if (recog_op_alt[i][alt].is_address)
1642 replaced
1643 = replace_oldest_value_addr (recog_data.operand_loc[i],
1644 recog_op_alt[i][alt].class,
1645 VOIDmode, insn, vd);
1646 else if (REG_P (recog_data.operand[i]))
1647 replaced
1648 = replace_oldest_value_reg (recog_data.operand_loc[i],
1649 recog_op_alt[i][alt].class,
1650 insn, vd);
1651 else if (GET_CODE (recog_data.operand[i]) == MEM)
1652 replaced = replace_oldest_value_mem (recog_data.operand[i],
1653 insn, vd);
1655 else if (GET_CODE (recog_data.operand[i]) == MEM)
1656 replaced = replace_oldest_value_mem (recog_data.operand[i],
1657 insn, vd);
1659 /* If we performed any replacement, update match_dups. */
1660 if (replaced)
1662 int j;
1663 rtx new;
1665 changed = true;
1667 new = *recog_data.operand_loc[i];
1668 recog_data.operand[i] = new;
1669 for (j = 0; j < recog_data.n_dups; j++)
1670 if (recog_data.dup_num[j] == i)
1671 *recog_data.dup_loc[j] = new;
1675 did_replacement:
1676 /* Clobber call-clobbered registers. */
1677 if (GET_CODE (insn) == CALL_INSN)
1678 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1679 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1680 kill_value_regno (i, vd);
1682 /* Notice stores. */
1683 note_stores (PATTERN (insn), kill_set_value, vd);
1685 /* Notice copies. */
1686 if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
1687 copy_value (SET_DEST (set), SET_SRC (set), vd);
1689 if (insn == bb->end)
1690 break;
1693 return changed;
1696 /* Main entry point for the forward copy propagation optimization. */
1698 void
1699 copyprop_hardreg_forward ()
1701 struct value_data *all_vd;
1702 bool need_refresh;
1703 int b;
1705 need_refresh = false;
1707 all_vd = xmalloc (sizeof (struct value_data) * n_basic_blocks);
1709 for (b = 0; b < n_basic_blocks; b++)
1711 basic_block bb = BASIC_BLOCK (b);
1713 /* If a block has a single predecessor, that we've already
1714 processed, begin with the value data that was live at
1715 the end of the predecessor block. */
1716 /* ??? Ought to use more intelligent queueing of blocks. */
1717 if (bb->pred
1718 && ! bb->pred->pred_next
1719 && ! (bb->pred->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1720 && bb->pred->src->index != ENTRY_BLOCK
1721 && bb->pred->src->index < b)
1722 all_vd[b] = all_vd[bb->pred->src->index];
1723 else
1724 init_value_data (all_vd + b);
1726 if (copyprop_hardreg_forward_1 (bb, all_vd + b))
1727 need_refresh = true;
1730 if (need_refresh)
1732 if (rtl_dump_file)
1733 fputs ("\n\n", rtl_dump_file);
1735 /* ??? Irritatingly, delete_noop_moves does not take a set of blocks
1736 to scan, so we have to do a life update with no initial set of
1737 blocks Just In Case. */
1738 delete_noop_moves (get_insns ());
1739 update_life_info (NULL, UPDATE_LIFE_GLOBAL_RM_NOTES,
1740 PROP_DEATH_NOTES
1741 | PROP_SCAN_DEAD_CODE
1742 | PROP_KILL_DEAD_CODE);
1745 free (all_vd);
1748 /* Dump the value chain data to stderr. */
1750 void
1751 debug_value_data (vd)
1752 struct value_data *vd;
1754 HARD_REG_SET set;
1755 unsigned int i, j;
1757 CLEAR_HARD_REG_SET (set);
1759 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1760 if (vd->e[i].oldest_regno == i)
1762 if (vd->e[i].mode == VOIDmode)
1764 if (vd->e[i].next_regno != INVALID_REGNUM)
1765 fprintf (stderr, "[%u] Bad next_regno for empty chain (%u)\n",
1766 i, vd->e[i].next_regno);
1767 continue;
1770 SET_HARD_REG_BIT (set, i);
1771 fprintf (stderr, "[%u %s] ", i, GET_MODE_NAME (vd->e[i].mode));
1773 for (j = vd->e[i].next_regno;
1774 j != INVALID_REGNUM;
1775 j = vd->e[j].next_regno)
1777 if (TEST_HARD_REG_BIT (set, j))
1779 fprintf (stderr, "[%u] Loop in regno chain\n", j);
1780 return;
1783 if (vd->e[j].oldest_regno != i)
1785 fprintf (stderr, "[%u] Bad oldest_regno (%u)\n",
1786 j, vd->e[j].oldest_regno);
1787 return;
1789 SET_HARD_REG_BIT (set, j);
1790 fprintf (stderr, "[%u %s] ", j, GET_MODE_NAME (vd->e[j].mode));
1792 fputc ('\n', stderr);
1795 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1796 if (! TEST_HARD_REG_BIT (set, i)
1797 && (vd->e[i].mode != VOIDmode
1798 || vd->e[i].oldest_regno != i
1799 || vd->e[i].next_regno != INVALID_REGNUM))
1800 fprintf (stderr, "[%u] Non-empty reg in chain (%s %u %i)\n",
1801 i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1802 vd->e[i].next_regno);
1805 #ifdef ENABLE_CHECKING
1806 static void
1807 validate_value_data (vd)
1808 struct value_data *vd;
1810 HARD_REG_SET set;
1811 unsigned int i, j;
1813 CLEAR_HARD_REG_SET (set);
1815 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1816 if (vd->e[i].oldest_regno == i)
1818 if (vd->e[i].mode == VOIDmode)
1820 if (vd->e[i].next_regno != INVALID_REGNUM)
1821 internal_error ("validate_value_data: [%u] Bad next_regno for empty chain (%u)",
1822 i, vd->e[i].next_regno);
1823 continue;
1826 SET_HARD_REG_BIT (set, i);
1828 for (j = vd->e[i].next_regno;
1829 j != INVALID_REGNUM;
1830 j = vd->e[j].next_regno)
1832 if (TEST_HARD_REG_BIT (set, j))
1833 internal_error ("validate_value_data: Loop in regno chain (%u)",
1835 if (vd->e[j].oldest_regno != i)
1836 internal_error ("validate_value_data: [%u] Bad oldest_regno (%u)",
1837 j, vd->e[j].oldest_regno);
1839 SET_HARD_REG_BIT (set, j);
1843 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1844 if (! TEST_HARD_REG_BIT (set, i)
1845 && (vd->e[i].mode != VOIDmode
1846 || vd->e[i].oldest_regno != i
1847 || vd->e[i].next_regno != INVALID_REGNUM))
1848 internal_error ("validate_value_data: [%u] Non-empty reg in chain (%s %u %i)",
1849 i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno,
1850 vd->e[i].next_regno);
1852 #endif