1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* This is the jump-optimization pass of the compiler.
24 It is run two or three times: once before cse, sometimes once after cse,
25 and once after reload (before final).
27 jump_optimize deletes unreachable code and labels that are not used.
28 It also deletes jumps that jump to the following insn,
29 and simplifies jumps around unconditional jumps and jumps
30 to unconditional jumps.
32 Each CODE_LABEL has a count of the times it is used
33 stored in the LABEL_NUSES internal field, and each JUMP_INSN
34 has one label that it refers to stored in the
35 JUMP_LABEL internal field. With this we can detect labels that
36 become unused because of the deletion of all the jumps that
37 formerly used them. The JUMP_LABEL info is sometimes looked
40 Optionally, cross-jumping can be done. Currently it is done
41 only the last time (when after reload and before final).
42 In fact, the code for cross-jumping now assumes that register
43 allocation has been done, since it uses `rtx_renumbered_equal_p'.
45 Jump optimization is done after cse when cse's constant-propagation
46 causes jumps to become unconditional or to be deleted.
48 Unreachable loops are not detected here, because the labels
49 have references and the insns appear reachable from the labels.
50 find_basic_blocks in flow.c finds and deletes such loops.
52 The subroutines delete_insn, redirect_jump, and invert_jump are used
53 from other passes as well. */
60 #include "hard-reg-set.h"
62 #include "insn-config.h"
63 #include "insn-flags.h"
64 #include "insn-attr.h"
72 /* ??? Eventually must record somehow the labels used by jumps
73 from nested functions. */
74 /* Pre-record the next or previous real insn for each label?
75 No, this pass is very fast anyway. */
76 /* Condense consecutive labels?
77 This would make life analysis faster, maybe. */
78 /* Optimize jump y; x: ... y: jumpif... x?
79 Don't know if it is worth bothering with. */
80 /* Optimize two cases of conditional jump to conditional jump?
81 This can never delete any instruction or make anything dead,
82 or even change what is live at any point.
83 So perhaps let combiner do it. */
85 /* Vector indexed by uid.
86 For each CODE_LABEL, index by its uid to get first unconditional jump
87 that jumps to the label.
88 For each JUMP_INSN, index by its uid to get the next unconditional jump
89 that jumps to the same label.
90 Element 0 is the start of a chain of all return insns.
91 (It is safe to use element 0 because insn uid 0 is not used. */
93 static rtx *jump_chain;
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain;
99 /* Set nonzero by jump_optimize if control can fall through
100 to the end of the function. */
103 /* Indicates whether death notes are significant in cross jump analysis.
104 Normally they are not significant, because of A and B jump to C,
105 and R dies in A, it must die in B. But this might not be true after
106 stack register conversion, and we must compare death notes in that
109 static int cross_jump_death_matters = 0;
111 static int init_label_info PARAMS ((rtx));
112 static void delete_barrier_successors PARAMS ((rtx));
113 static void mark_all_labels PARAMS ((rtx, int));
114 static rtx delete_unreferenced_labels PARAMS ((rtx));
115 static void delete_noop_moves PARAMS ((rtx));
116 static int calculate_can_reach_end PARAMS ((rtx, int));
117 static int duplicate_loop_exit_test PARAMS ((rtx));
118 static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
119 static void do_cross_jump PARAMS ((rtx, rtx, rtx));
120 static int jump_back_p PARAMS ((rtx, rtx));
121 static int tension_vector_labels PARAMS ((rtx, int));
122 static void mark_jump_label PARAMS ((rtx, rtx, int, int));
123 static void delete_computation PARAMS ((rtx));
124 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
125 static void invert_exp_1 PARAMS ((rtx, rtx));
126 static void delete_from_jump_chain PARAMS ((rtx));
127 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
128 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
129 static void redirect_tablejump PARAMS ((rtx, rtx));
130 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
131 static int returnjump_p_1 PARAMS ((rtx *, void *));
132 static void delete_prior_computation PARAMS ((rtx, rtx));
134 /* Main external entry point into the jump optimizer. See comments before
135 jump_optimize_1 for descriptions of the arguments. */
137 jump_optimize (f, cross_jump, noop_moves, after_regscan)
143 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
146 /* Alternate entry into the jump optimizer. This entry point only rebuilds
147 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
150 rebuild_jump_labels (f)
153 jump_optimize_1 (f, 0, 0, 0, 1, 0);
156 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
158 jump_optimize_minimal (f)
161 jump_optimize_1 (f, 0, 0, 0, 0, 1);
164 /* Delete no-op jumps and optimize jumps to jumps
165 and jumps around jumps.
166 Delete unused labels and unreachable code.
168 If CROSS_JUMP is 1, detect matching code
169 before a jump and its destination and unify them.
170 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
172 If NOOP_MOVES is nonzero, delete no-op move insns.
174 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
175 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
177 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
178 and JUMP_LABEL field for jumping insns.
180 If `optimize' is zero, don't change any code,
181 just determine whether control drops off the end of the function.
182 This case occurs when we have -W and not -O.
183 It works because `delete_insn' checks the value of `optimize'
184 and refrains from actually deleting when that is 0.
186 If MINIMAL is nonzero, then we only perform trivial optimizations:
188 * Removal of unreachable code after BARRIERs.
189 * Removal of unreferenced CODE_LABELs.
190 * Removal of a jump to the next instruction.
191 * Removal of a conditional jump followed by an unconditional jump
192 to the same target as the conditional jump.
193 * Simplify a conditional jump around an unconditional jump.
194 * Simplify a jump to a jump.
195 * Delete extraneous line number notes.
199 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
200 mark_labels_only, minimal)
205 int mark_labels_only;
208 register rtx insn, next;
215 cross_jump_death_matters = (cross_jump == 2);
216 max_uid = init_label_info (f) + 1;
218 /* If we are performing cross jump optimizations, then initialize
219 tables mapping UIDs to EH regions to avoid incorrect movement
220 of insns from one EH region to another. */
221 if (flag_exceptions && cross_jump)
222 init_insn_eh_region (f, max_uid);
224 if (! mark_labels_only)
225 delete_barrier_successors (f);
227 /* Leave some extra room for labels and duplicate exit test insns
229 max_jump_chain = max_uid * 14 / 10;
230 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
232 mark_all_labels (f, cross_jump);
234 /* Keep track of labels used from static data; we don't track them
235 closely enough to delete them here, so make sure their reference
236 count doesn't drop to zero. */
238 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
239 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
240 LABEL_NUSES (XEXP (insn, 0))++;
242 check_exception_handler_labels ();
244 /* Keep track of labels used for marking handlers for exception
245 regions; they cannot usually be deleted. */
247 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
248 LABEL_NUSES (XEXP (insn, 0))++;
250 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
251 notes and recompute LABEL_NUSES. */
252 if (mark_labels_only)
256 exception_optimize ();
258 last_insn = delete_unreferenced_labels (f);
261 delete_noop_moves (f);
263 /* If we haven't yet gotten to reload and we have just run regscan,
264 delete any insn that sets a register that isn't used elsewhere.
265 This helps some of the optimizations below by having less insns
266 being jumped around. */
268 if (optimize && ! reload_completed && after_regscan)
269 for (insn = f; insn; insn = next)
271 rtx set = single_set (insn);
273 next = NEXT_INSN (insn);
275 if (set && GET_CODE (SET_DEST (set)) == REG
276 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
277 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
278 /* We use regno_last_note_uid so as not to delete the setting
279 of a reg that's used in notes. A subsequent optimization
280 might arrange to use that reg for real. */
281 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
282 && ! side_effects_p (SET_SRC (set))
283 && ! find_reg_note (insn, REG_RETVAL, 0)
284 /* An ADDRESSOF expression can turn into a use of the internal arg
285 pointer, so do not delete the initialization of the internal
286 arg pointer yet. If it is truly dead, flow will delete the
287 initializing insn. */
288 && SET_DEST (set) != current_function_internal_arg_pointer)
292 /* Now iterate optimizing jumps until nothing changes over one pass. */
294 old_max_reg = max_reg_num ();
299 for (insn = f; insn; insn = next)
302 rtx temp, temp1, temp2 = NULL_RTX;
303 rtx temp4 ATTRIBUTE_UNUSED;
305 int this_is_simplejump, this_is_condjump;
306 int this_is_condjump_in_parallel;
308 next = NEXT_INSN (insn);
310 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
311 jump. Try to optimize by duplicating the loop exit test if so.
312 This is only safe immediately after regscan, because it uses
313 the values of regno_first_uid and regno_last_uid. */
314 if (after_regscan && GET_CODE (insn) == NOTE
315 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
316 && (temp1 = next_nonnote_insn (insn)) != 0
317 && simplejump_p (temp1))
319 temp = PREV_INSN (insn);
320 if (duplicate_loop_exit_test (insn))
323 next = NEXT_INSN (temp);
328 if (GET_CODE (insn) != JUMP_INSN)
331 this_is_simplejump = simplejump_p (insn);
332 this_is_condjump = condjump_p (insn);
333 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
335 /* Tension the labels in dispatch tables. */
337 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
338 changed |= tension_vector_labels (PATTERN (insn), 0);
339 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
340 changed |= tension_vector_labels (PATTERN (insn), 1);
342 /* See if this jump goes to another jump and redirect if so. */
343 nlabel = follow_jumps (JUMP_LABEL (insn));
344 if (nlabel != JUMP_LABEL (insn))
345 changed |= redirect_jump (insn, nlabel);
347 if (! optimize || minimal)
350 /* If a dispatch table always goes to the same place,
351 get rid of it and replace the insn that uses it. */
353 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
354 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
357 rtx pat = PATTERN (insn);
358 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
359 int len = XVECLEN (pat, diff_vec_p);
360 rtx dispatch = prev_real_insn (insn);
363 for (i = 0; i < len; i++)
364 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
365 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
370 && GET_CODE (dispatch) == JUMP_INSN
371 && JUMP_LABEL (dispatch) != 0
372 /* Don't mess with a casesi insn.
373 XXX according to the comment before computed_jump_p(),
374 all casesi insns should be a parallel of the jump
375 and a USE of a LABEL_REF. */
376 && ! ((set = single_set (dispatch)) != NULL
377 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
378 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
380 redirect_tablejump (dispatch,
381 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
386 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
388 /* Detect jump to following insn. */
389 if (reallabelprev == insn && this_is_condjump)
391 next = next_real_insn (JUMP_LABEL (insn));
397 /* Detect a conditional jump going to the same place
398 as an immediately following unconditional jump. */
399 else if (this_is_condjump
400 && (temp = next_active_insn (insn)) != 0
401 && simplejump_p (temp)
402 && (next_active_insn (JUMP_LABEL (insn))
403 == next_active_insn (JUMP_LABEL (temp))))
405 /* Don't mess up test coverage analysis. */
407 if (flag_test_coverage && !reload_completed)
408 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
409 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
420 /* Detect a conditional jump jumping over an unconditional jump. */
422 else if ((this_is_condjump || this_is_condjump_in_parallel)
423 && ! this_is_simplejump
424 && reallabelprev != 0
425 && GET_CODE (reallabelprev) == JUMP_INSN
426 && prev_active_insn (reallabelprev) == insn
427 && no_labels_between_p (insn, reallabelprev)
428 && simplejump_p (reallabelprev))
430 /* When we invert the unconditional jump, we will be
431 decrementing the usage count of its old label.
432 Make sure that we don't delete it now because that
433 might cause the following code to be deleted. */
434 rtx prev_uses = prev_nonnote_insn (reallabelprev);
435 rtx prev_label = JUMP_LABEL (insn);
438 ++LABEL_NUSES (prev_label);
440 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
442 /* It is very likely that if there are USE insns before
443 this jump, they hold REG_DEAD notes. These REG_DEAD
444 notes are no longer valid due to this optimization,
445 and will cause the life-analysis that following passes
446 (notably delayed-branch scheduling) to think that
447 these registers are dead when they are not.
449 To prevent this trouble, we just remove the USE insns
450 from the insn chain. */
452 while (prev_uses && GET_CODE (prev_uses) == INSN
453 && GET_CODE (PATTERN (prev_uses)) == USE)
455 rtx useless = prev_uses;
456 prev_uses = prev_nonnote_insn (prev_uses);
457 delete_insn (useless);
460 delete_insn (reallabelprev);
464 /* We can now safely delete the label if it is unreferenced
465 since the delete_insn above has deleted the BARRIER. */
466 if (prev_label && --LABEL_NUSES (prev_label) == 0)
467 delete_insn (prev_label);
469 next = NEXT_INSN (insn);
472 /* If we have an unconditional jump preceded by a USE, try to put
473 the USE before the target and jump there. This simplifies many
474 of the optimizations below since we don't have to worry about
475 dealing with these USE insns. We only do this if the label
476 being branch to already has the identical USE or if code
477 never falls through to that label. */
479 else if (this_is_simplejump
480 && (temp = prev_nonnote_insn (insn)) != 0
481 && GET_CODE (temp) == INSN
482 && GET_CODE (PATTERN (temp)) == USE
483 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
484 && (GET_CODE (temp1) == BARRIER
485 || (GET_CODE (temp1) == INSN
486 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
487 /* Don't do this optimization if we have a loop containing
488 only the USE instruction, and the loop start label has
489 a usage count of 1. This is because we will redo this
490 optimization everytime through the outer loop, and jump
491 opt will never exit. */
492 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
493 && temp2 == JUMP_LABEL (insn)
494 && LABEL_NUSES (temp2) == 1))
496 if (GET_CODE (temp1) == BARRIER)
498 emit_insn_after (PATTERN (temp), temp1);
499 temp1 = NEXT_INSN (temp1);
503 redirect_jump (insn, get_label_before (temp1));
504 reallabelprev = prev_real_insn (temp1);
506 next = NEXT_INSN (insn);
510 /* Detect a conditional jump jumping over an unconditional trap. */
512 && this_is_condjump && ! this_is_simplejump
513 && reallabelprev != 0
514 && GET_CODE (reallabelprev) == INSN
515 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
516 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
517 && prev_active_insn (reallabelprev) == insn
518 && no_labels_between_p (insn, reallabelprev)
519 && (temp2 = get_condition (insn, &temp4))
520 && can_reverse_comparison_p (temp2, insn))
522 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
523 XEXP (temp2, 0), XEXP (temp2, 1),
524 TRAP_CODE (PATTERN (reallabelprev)));
528 emit_insn_before (new, temp4);
529 delete_insn (reallabelprev);
535 /* Detect a jump jumping to an unconditional trap. */
536 else if (HAVE_trap && this_is_condjump
537 && (temp = next_active_insn (JUMP_LABEL (insn)))
538 && GET_CODE (temp) == INSN
539 && GET_CODE (PATTERN (temp)) == TRAP_IF
540 && (this_is_simplejump
541 || (temp2 = get_condition (insn, &temp4))))
543 rtx tc = TRAP_CONDITION (PATTERN (temp));
545 if (tc == const_true_rtx
546 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
549 /* Replace an unconditional jump to a trap with a trap. */
550 if (this_is_simplejump)
552 emit_barrier_after (emit_insn_before (gen_trap (), insn));
557 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
559 TRAP_CODE (PATTERN (temp)));
562 emit_insn_before (new, temp4);
568 /* If the trap condition and jump condition are mutually
569 exclusive, redirect the jump to the following insn. */
570 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
571 && ! this_is_simplejump
572 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
573 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
574 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
575 && redirect_jump (insn, get_label_after (temp)))
584 /* Now that the jump has been tensioned,
585 try cross jumping: check for identical code
586 before the jump and before its target label. */
588 /* First, cross jumping of conditional jumps: */
590 if (cross_jump && condjump_p (insn))
592 rtx newjpos, newlpos;
593 rtx x = prev_real_insn (JUMP_LABEL (insn));
595 /* A conditional jump may be crossjumped
596 only if the place it jumps to follows
597 an opposing jump that comes back here. */
599 if (x != 0 && ! jump_back_p (x, insn))
600 /* We have no opposing jump;
601 cannot cross jump this insn. */
605 /* TARGET is nonzero if it is ok to cross jump
606 to code before TARGET. If so, see if matches. */
608 find_cross_jump (insn, x, 2,
613 do_cross_jump (insn, newjpos, newlpos);
614 /* Make the old conditional jump
615 into an unconditional one. */
616 SET_SRC (PATTERN (insn))
617 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
618 INSN_CODE (insn) = -1;
619 emit_barrier_after (insn);
620 /* Add to jump_chain unless this is a new label
621 whose UID is too large. */
622 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
624 jump_chain[INSN_UID (insn)]
625 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
626 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
633 /* Cross jumping of unconditional jumps:
634 a few differences. */
636 if (cross_jump && simplejump_p (insn))
638 rtx newjpos, newlpos;
643 /* TARGET is nonzero if it is ok to cross jump
644 to code before TARGET. If so, see if matches. */
645 find_cross_jump (insn, JUMP_LABEL (insn), 1,
648 /* If cannot cross jump to code before the label,
649 see if we can cross jump to another jump to
651 /* Try each other jump to this label. */
652 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
653 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
654 target != 0 && newjpos == 0;
655 target = jump_chain[INSN_UID (target)])
657 && JUMP_LABEL (target) == JUMP_LABEL (insn)
658 /* Ignore TARGET if it's deleted. */
659 && ! INSN_DELETED_P (target))
660 find_cross_jump (insn, target, 2,
665 do_cross_jump (insn, newjpos, newlpos);
671 /* This code was dead in the previous jump.c! */
672 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
674 /* Return insns all "jump to the same place"
675 so we can cross-jump between any two of them. */
677 rtx newjpos, newlpos, target;
681 /* If cannot cross jump to code before the label,
682 see if we can cross jump to another jump to
684 /* Try each other jump to this label. */
685 for (target = jump_chain[0];
686 target != 0 && newjpos == 0;
687 target = jump_chain[INSN_UID (target)])
689 && ! INSN_DELETED_P (target)
690 && GET_CODE (PATTERN (target)) == RETURN)
691 find_cross_jump (insn, target, 2,
696 do_cross_jump (insn, newjpos, newlpos);
707 /* Delete extraneous line number notes.
708 Note that two consecutive notes for different lines are not really
709 extraneous. There should be some indication where that line belonged,
710 even if it became empty. */
715 for (insn = f; insn; insn = NEXT_INSN (insn))
716 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
718 /* Delete this note if it is identical to previous note. */
720 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
721 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
731 /* CAN_REACH_END is persistent for each function. Once set it should
732 not be cleared. This is especially true for the case where we
733 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
734 the front-end before compiling each function. */
735 if (! minimal && calculate_can_reach_end (last_insn, optimize != 0))
744 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
745 notes whose labels don't occur in the insn any more. Returns the
746 largest INSN_UID found. */
754 for (insn = f; insn; insn = NEXT_INSN (insn))
756 if (GET_CODE (insn) == CODE_LABEL)
757 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
758 else if (GET_CODE (insn) == JUMP_INSN)
759 JUMP_LABEL (insn) = 0;
760 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
764 for (note = REG_NOTES (insn); note; note = next)
766 next = XEXP (note, 1);
767 if (REG_NOTE_KIND (note) == REG_LABEL
768 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
769 remove_note (insn, note);
772 if (INSN_UID (insn) > largest_uid)
773 largest_uid = INSN_UID (insn);
779 /* Delete insns following barriers, up to next label.
781 Also delete no-op jumps created by gcse. */
784 delete_barrier_successors (f)
789 for (insn = f; insn;)
791 if (GET_CODE (insn) == BARRIER)
793 insn = NEXT_INSN (insn);
795 never_reached_warning (insn);
797 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
799 if (GET_CODE (insn) == NOTE
800 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
801 insn = NEXT_INSN (insn);
803 insn = delete_insn (insn);
805 /* INSN is now the code_label. */
808 /* Also remove (set (pc) (pc)) insns which can be created by
809 gcse. We eliminate such insns now to avoid having them
810 cause problems later. */
811 else if (GET_CODE (insn) == JUMP_INSN
812 && GET_CODE (PATTERN (insn)) == SET
813 && SET_SRC (PATTERN (insn)) == pc_rtx
814 && SET_DEST (PATTERN (insn)) == pc_rtx)
815 insn = delete_insn (insn);
818 insn = NEXT_INSN (insn);
822 /* Mark the label each jump jumps to.
823 Combine consecutive labels, and count uses of labels.
825 For each label, make a chain (using `jump_chain')
826 of all the *unconditional* jumps that jump to it;
827 also make a chain of all returns.
829 CROSS_JUMP indicates whether we are doing cross jumping
830 and if we are whether we will be paying attention to
831 death notes or not. */
834 mark_all_labels (f, cross_jump)
840 for (insn = f; insn; insn = NEXT_INSN (insn))
841 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
843 if (GET_CODE (insn) == CALL_INSN
844 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
846 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
847 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
848 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
852 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
853 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
855 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
857 jump_chain[INSN_UID (insn)]
858 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
859 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
861 if (GET_CODE (PATTERN (insn)) == RETURN)
863 jump_chain[INSN_UID (insn)] = jump_chain[0];
864 jump_chain[0] = insn;
870 /* Delete all labels already not referenced.
871 Also find and return the last insn. */
874 delete_unreferenced_labels (f)
877 rtx final = NULL_RTX;
880 for (insn = f; insn; )
882 if (GET_CODE (insn) == CODE_LABEL
883 && LABEL_NUSES (insn) == 0
884 && LABEL_ALTERNATE_NAME (insn) == NULL)
885 insn = delete_insn (insn);
889 insn = NEXT_INSN (insn);
896 /* Delete various simple forms of moves which have no necessary
900 delete_noop_moves (f)
905 for (insn = f; insn; )
907 next = NEXT_INSN (insn);
909 if (GET_CODE (insn) == INSN)
911 register rtx body = PATTERN (insn);
913 /* Detect and delete no-op move instructions
914 resulting from not allocating a parameter in a register. */
916 if (GET_CODE (body) == SET
917 && (SET_DEST (body) == SET_SRC (body)
918 || (GET_CODE (SET_DEST (body)) == MEM
919 && GET_CODE (SET_SRC (body)) == MEM
920 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
921 && ! (GET_CODE (SET_DEST (body)) == MEM
922 && MEM_VOLATILE_P (SET_DEST (body)))
923 && ! (GET_CODE (SET_SRC (body)) == MEM
924 && MEM_VOLATILE_P (SET_SRC (body))))
925 delete_computation (insn);
927 /* Detect and ignore no-op move instructions
928 resulting from smart or fortuitous register allocation. */
930 else if (GET_CODE (body) == SET)
932 int sreg = true_regnum (SET_SRC (body));
933 int dreg = true_regnum (SET_DEST (body));
935 if (sreg == dreg && sreg >= 0)
937 else if (sreg >= 0 && dreg >= 0)
940 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
941 sreg, NULL_PTR, dreg,
942 GET_MODE (SET_SRC (body)));
945 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
947 /* DREG may have been the target of a REG_DEAD note in
948 the insn which makes INSN redundant. If so, reorg
949 would still think it is dead. So search for such a
950 note and delete it if we find it. */
951 if (! find_regno_note (insn, REG_UNUSED, dreg))
952 for (trial = prev_nonnote_insn (insn);
953 trial && GET_CODE (trial) != CODE_LABEL;
954 trial = prev_nonnote_insn (trial))
955 if (find_regno_note (trial, REG_DEAD, dreg))
957 remove_death (dreg, trial);
961 /* Deleting insn could lose a death-note for SREG. */
962 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
964 /* Change this into a USE so that we won't emit
965 code for it, but still can keep the note. */
967 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
968 INSN_CODE (insn) = -1;
969 /* Remove all reg notes but the REG_DEAD one. */
970 REG_NOTES (insn) = trial;
971 XEXP (trial, 1) = NULL_RTX;
977 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
978 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
980 GET_MODE (SET_DEST (body))))
982 /* This handles the case where we have two consecutive
983 assignments of the same constant to pseudos that didn't
984 get a hard reg. Each SET from the constant will be
985 converted into a SET of the spill register and an
986 output reload will be made following it. This produces
987 two loads of the same constant into the same spill
992 /* Look back for a death note for the first reg.
993 If there is one, it is no longer accurate. */
994 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
996 if ((GET_CODE (in_insn) == INSN
997 || GET_CODE (in_insn) == JUMP_INSN)
998 && find_regno_note (in_insn, REG_DEAD, dreg))
1000 remove_death (dreg, in_insn);
1003 in_insn = PREV_INSN (in_insn);
1006 /* Delete the second load of the value. */
1010 else if (GET_CODE (body) == PARALLEL)
1012 /* If each part is a set between two identical registers or
1013 a USE or CLOBBER, delete the insn. */
1017 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1019 tem = XVECEXP (body, 0, i);
1020 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1023 if (GET_CODE (tem) != SET
1024 || (sreg = true_regnum (SET_SRC (tem))) < 0
1025 || (dreg = true_regnum (SET_DEST (tem))) < 0
1033 /* Also delete insns to store bit fields if they are no-ops. */
1034 /* Not worth the hair to detect this in the big-endian case. */
1035 else if (! BYTES_BIG_ENDIAN
1036 && GET_CODE (body) == SET
1037 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
1038 && XEXP (SET_DEST (body), 2) == const0_rtx
1039 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
1040 && ! (GET_CODE (SET_SRC (body)) == MEM
1041 && MEM_VOLATILE_P (SET_SRC (body))))
1048 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
1049 If so indicate that this function can drop off the end by returning
1052 CHECK_DELETED indicates whether we must check if the note being
1053 searched for has the deleted flag set.
1055 DELETE_FINAL_NOTE indicates whether we should delete the note
1059 calculate_can_reach_end (last, delete_final_note)
1061 int delete_final_note;
1066 while (insn != NULL_RTX)
1070 /* One label can follow the end-note: the return label. */
1071 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
1073 /* Ordinary insns can follow it if returning a structure. */
1074 else if (GET_CODE (insn) == INSN)
1076 /* If machine uses explicit RETURN insns, no epilogue,
1077 then one of them follows the note. */
1078 else if (GET_CODE (insn) == JUMP_INSN
1079 && GET_CODE (PATTERN (insn)) == RETURN)
1081 /* A barrier can follow the return insn. */
1082 else if (GET_CODE (insn) == BARRIER)
1084 /* Other kinds of notes can follow also. */
1085 else if (GET_CODE (insn) == NOTE
1086 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
1092 insn = PREV_INSN (insn);
1095 /* See if we backed up to the appropriate type of note. */
1096 if (insn != NULL_RTX
1097 && GET_CODE (insn) == NOTE
1098 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
1100 if (delete_final_note)
1108 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1109 jump. Assume that this unconditional jump is to the exit test code. If
1110 the code is sufficiently simple, make a copy of it before INSN,
1111 followed by a jump to the exit of the loop. Then delete the unconditional
1114 Return 1 if we made the change, else 0.
1116 This is only safe immediately after a regscan pass because it uses the
1117 values of regno_first_uid and regno_last_uid. */
1120 duplicate_loop_exit_test (loop_start)
1123 rtx insn, set, reg, p, link;
1124 rtx copy = 0, first_copy = 0;
1126 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1128 int max_reg = max_reg_num ();
1131 /* Scan the exit code. We do not perform this optimization if any insn:
1135 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1136 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1137 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1140 We also do not do this if we find an insn with ASM_OPERANDS. While
1141 this restriction should not be necessary, copying an insn with
1142 ASM_OPERANDS can confuse asm_noperands in some cases.
1144 Also, don't do this if the exit code is more than 20 insns. */
1146 for (insn = exitcode;
1148 && ! (GET_CODE (insn) == NOTE
1149 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1150 insn = NEXT_INSN (insn))
1152 switch (GET_CODE (insn))
1158 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1159 a jump immediately after the loop start that branches outside
1160 the loop but within an outer loop, near the exit test.
1161 If we copied this exit test and created a phony
1162 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1163 before the exit test look like these could be safely moved
1164 out of the loop even if they actually may be never executed.
1165 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1167 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1168 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1172 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1173 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1174 /* If we were to duplicate this code, we would not move
1175 the BLOCK notes, and so debugging the moved code would
1176 be difficult. Thus, we only move the code with -O2 or
1183 /* The code below would grossly mishandle REG_WAS_0 notes,
1184 so get rid of them here. */
1185 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1186 remove_note (insn, p);
1187 if (++num_insns > 20
1188 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1189 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1197 /* Unless INSN is zero, we can do the optimization. */
1203 /* See if any insn sets a register only used in the loop exit code and
1204 not a user variable. If so, replace it with a new register. */
1205 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1206 if (GET_CODE (insn) == INSN
1207 && (set = single_set (insn)) != 0
1208 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1209 || (GET_CODE (reg) == SUBREG
1210 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1211 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1212 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1214 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1215 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1220 /* We can do the replacement. Allocate reg_map if this is the
1221 first replacement we found. */
1223 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1225 REG_LOOP_TEST_P (reg) = 1;
1227 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1231 /* Now copy each insn. */
1232 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1234 switch (GET_CODE (insn))
1237 copy = emit_barrier_before (loop_start);
1240 /* Only copy line-number notes. */
1241 if (NOTE_LINE_NUMBER (insn) >= 0)
1243 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1244 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1249 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1251 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1253 mark_jump_label (PATTERN (copy), copy, 0, 0);
1255 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1257 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1258 if (REG_NOTE_KIND (link) != REG_LABEL)
1260 if (GET_CODE (link) == EXPR_LIST)
1262 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1267 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1272 if (reg_map && REG_NOTES (copy))
1273 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1277 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
1279 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1280 mark_jump_label (PATTERN (copy), copy, 0, 0);
1281 if (REG_NOTES (insn))
1283 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1285 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1288 /* If this is a simple jump, add it to the jump chain. */
1290 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1291 && simplejump_p (copy))
1293 jump_chain[INSN_UID (copy)]
1294 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1295 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1303 /* Record the first insn we copied. We need it so that we can
1304 scan the copied insns for new pseudo registers. */
1309 /* Now clean up by emitting a jump to the end label and deleting the jump
1310 at the start of the loop. */
1311 if (! copy || GET_CODE (copy) != BARRIER)
1313 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1316 /* Record the first insn we copied. We need it so that we can
1317 scan the copied insns for new pseudo registers. This may not
1318 be strictly necessary since we should have copied at least one
1319 insn above. But I am going to be safe. */
1323 mark_jump_label (PATTERN (copy), copy, 0, 0);
1324 if (INSN_UID (copy) < max_jump_chain
1325 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1327 jump_chain[INSN_UID (copy)]
1328 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1329 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1331 emit_barrier_before (loop_start);
1334 /* Now scan from the first insn we copied to the last insn we copied
1335 (copy) for new pseudo registers. Do this after the code to jump to
1336 the end label since that might create a new pseudo too. */
1337 reg_scan_update (first_copy, copy, max_reg);
1339 /* Mark the exit code as the virtual top of the converted loop. */
1340 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1342 delete_insn (next_nonnote_insn (loop_start));
1351 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1352 eh-beg, eh-end notes between START and END out before START. Assume that
1353 END is not such a note. START may be such a note. Returns the value
1354 of the new starting insn, which may be different if the original start
1358 squeeze_notes (start, end)
1364 for (insn = start; insn != end; insn = next)
1366 next = NEXT_INSN (insn);
1367 if (GET_CODE (insn) == NOTE
1368 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1369 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1370 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1371 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1372 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1373 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP
1374 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1375 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1381 rtx prev = PREV_INSN (insn);
1382 PREV_INSN (insn) = PREV_INSN (start);
1383 NEXT_INSN (insn) = start;
1384 NEXT_INSN (PREV_INSN (insn)) = insn;
1385 PREV_INSN (NEXT_INSN (insn)) = insn;
1386 NEXT_INSN (prev) = next;
1387 PREV_INSN (next) = prev;
1395 /* Compare the instructions before insn E1 with those before E2
1396 to find an opportunity for cross jumping.
1397 (This means detecting identical sequences of insns followed by
1398 jumps to the same place, or followed by a label and a jump
1399 to that label, and replacing one with a jump to the other.)
1401 Assume E1 is a jump that jumps to label E2
1402 (that is not always true but it might as well be).
1403 Find the longest possible equivalent sequences
1404 and store the first insns of those sequences into *F1 and *F2.
1405 Store zero there if no equivalent preceding instructions are found.
1407 We give up if we find a label in stream 1.
1408 Actually we could transfer that label into stream 2. */
1411 find_cross_jump (e1, e2, minimum, f1, f2)
1416 register rtx i1 = e1, i2 = e2;
1417 register rtx p1, p2;
1420 rtx last1 = 0, last2 = 0;
1421 rtx afterlast1 = 0, afterlast2 = 0;
1428 i1 = prev_nonnote_insn (i1);
1430 i2 = PREV_INSN (i2);
1431 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1432 i2 = PREV_INSN (i2);
1437 /* Don't allow the range of insns preceding E1 or E2
1438 to include the other (E2 or E1). */
1439 if (i2 == e1 || i1 == e2)
1442 /* If we will get to this code by jumping, those jumps will be
1443 tensioned to go directly to the new label (before I2),
1444 so this cross-jumping won't cost extra. So reduce the minimum. */
1445 if (GET_CODE (i1) == CODE_LABEL)
1451 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1454 /* Avoid moving insns across EH regions if either of the insns
1457 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
1458 && !in_same_eh_region (i1, i2))
1464 /* If this is a CALL_INSN, compare register usage information.
1465 If we don't check this on stack register machines, the two
1466 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1467 numbers of stack registers in the same basic block.
1468 If we don't check this on machines with delay slots, a delay slot may
1469 be filled that clobbers a parameter expected by the subroutine.
1471 ??? We take the simple route for now and assume that if they're
1472 equal, they were constructed identically. */
1474 if (GET_CODE (i1) == CALL_INSN
1475 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1476 CALL_INSN_FUNCTION_USAGE (i2)))
1480 /* If cross_jump_death_matters is not 0, the insn's mode
1481 indicates whether or not the insn contains any stack-like
1484 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1486 /* If register stack conversion has already been done, then
1487 death notes must also be compared before it is certain that
1488 the two instruction streams match. */
1491 HARD_REG_SET i1_regset, i2_regset;
1493 CLEAR_HARD_REG_SET (i1_regset);
1494 CLEAR_HARD_REG_SET (i2_regset);
1496 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1497 if (REG_NOTE_KIND (note) == REG_DEAD
1498 && STACK_REG_P (XEXP (note, 0)))
1499 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1501 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1502 if (REG_NOTE_KIND (note) == REG_DEAD
1503 && STACK_REG_P (XEXP (note, 0)))
1504 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1506 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1515 /* Don't allow old-style asm or volatile extended asms to be accepted
1516 for cross jumping purposes. It is conceptually correct to allow
1517 them, since cross-jumping preserves the dynamic instruction order
1518 even though it is changing the static instruction order. However,
1519 if an asm is being used to emit an assembler pseudo-op, such as
1520 the MIPS `.set reorder' pseudo-op, then the static instruction order
1521 matters and it must be preserved. */
1522 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1523 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1524 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1527 if (lose || GET_CODE (p1) != GET_CODE (p2)
1528 || ! rtx_renumbered_equal_p (p1, p2))
1530 /* The following code helps take care of G++ cleanups. */
1534 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1535 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1536 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1537 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1538 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1539 /* If the equivalences are not to a constant, they may
1540 reference pseudos that no longer exist, so we can't
1542 && CONSTANT_P (XEXP (equiv1, 0))
1543 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1545 rtx s1 = single_set (i1);
1546 rtx s2 = single_set (i2);
1547 if (s1 != 0 && s2 != 0
1548 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1550 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1551 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1552 if (! rtx_renumbered_equal_p (p1, p2))
1554 else if (apply_change_group ())
1559 /* Insns fail to match; cross jumping is limited to the following
1563 /* Don't allow the insn after a compare to be shared by
1564 cross-jumping unless the compare is also shared.
1565 Here, if either of these non-matching insns is a compare,
1566 exclude the following insn from possible cross-jumping. */
1567 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1568 last1 = afterlast1, last2 = afterlast2, ++minimum;
1571 /* If cross-jumping here will feed a jump-around-jump
1572 optimization, this jump won't cost extra, so reduce
1574 if (GET_CODE (i1) == JUMP_INSN
1576 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1582 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1584 /* Ok, this insn is potentially includable in a cross-jump here. */
1585 afterlast1 = last1, afterlast2 = last2;
1586 last1 = i1, last2 = i2, --minimum;
1590 if (minimum <= 0 && last1 != 0 && last1 != e1)
1591 *f1 = last1, *f2 = last2;
1595 do_cross_jump (insn, newjpos, newlpos)
1596 rtx insn, newjpos, newlpos;
1598 /* Find an existing label at this point
1599 or make a new one if there is none. */
1600 register rtx label = get_label_before (newlpos);
1602 /* Make the same jump insn jump to the new point. */
1603 if (GET_CODE (PATTERN (insn)) == RETURN)
1605 /* Remove from jump chain of returns. */
1606 delete_from_jump_chain (insn);
1607 /* Change the insn. */
1608 PATTERN (insn) = gen_jump (label);
1609 INSN_CODE (insn) = -1;
1610 JUMP_LABEL (insn) = label;
1611 LABEL_NUSES (label)++;
1612 /* Add to new the jump chain. */
1613 if (INSN_UID (label) < max_jump_chain
1614 && INSN_UID (insn) < max_jump_chain)
1616 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1617 jump_chain[INSN_UID (label)] = insn;
1621 redirect_jump (insn, label);
1623 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1624 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1625 the NEWJPOS stream. */
1627 while (newjpos != insn)
1631 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1632 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1633 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1634 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1635 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1636 remove_note (newlpos, lnote);
1638 delete_insn (newjpos);
1639 newjpos = next_real_insn (newjpos);
1640 newlpos = next_real_insn (newlpos);
1644 /* Return the label before INSN, or put a new label there. */
1647 get_label_before (insn)
1652 /* Find an existing label at this point
1653 or make a new one if there is none. */
1654 label = prev_nonnote_insn (insn);
1656 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1658 rtx prev = PREV_INSN (insn);
1660 label = gen_label_rtx ();
1661 emit_label_after (label, prev);
1662 LABEL_NUSES (label) = 0;
1667 /* Return the label after INSN, or put a new label there. */
1670 get_label_after (insn)
1675 /* Find an existing label at this point
1676 or make a new one if there is none. */
1677 label = next_nonnote_insn (insn);
1679 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1681 label = gen_label_rtx ();
1682 emit_label_after (label, insn);
1683 LABEL_NUSES (label) = 0;
1688 /* Return 1 if INSN is a jump that jumps to right after TARGET
1689 only on the condition that TARGET itself would drop through.
1690 Assumes that TARGET is a conditional jump. */
1693 jump_back_p (insn, target)
1697 enum rtx_code codei, codet;
1699 if (simplejump_p (insn) || ! condjump_p (insn)
1700 || simplejump_p (target)
1701 || target != prev_real_insn (JUMP_LABEL (insn)))
1704 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
1705 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
1707 codei = GET_CODE (cinsn);
1708 codet = GET_CODE (ctarget);
1710 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
1712 if (! can_reverse_comparison_p (cinsn, insn))
1714 codei = reverse_condition (codei);
1717 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
1719 if (! can_reverse_comparison_p (ctarget, target))
1721 codet = reverse_condition (codet);
1724 return (codei == codet
1725 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1726 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1729 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1730 return non-zero if it is safe to reverse this comparison. It is if our
1731 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1732 this is known to be an integer comparison. */
1735 can_reverse_comparison_p (comparison, insn)
1741 /* If this is not actually a comparison, we can't reverse it. */
1742 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1745 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1746 /* If this is an NE comparison, it is safe to reverse it to an EQ
1747 comparison and vice versa, even for floating point. If no operands
1748 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
1749 always false and NE is always true, so the reversal is also valid. */
1751 || GET_CODE (comparison) == NE
1752 || GET_CODE (comparison) == EQ)
1755 arg0 = XEXP (comparison, 0);
1757 /* Make sure ARG0 is one of the actual objects being compared. If we
1758 can't do this, we can't be sure the comparison can be reversed.
1760 Handle cc0 and a MODE_CC register. */
1761 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
1767 rtx prev = prev_nonnote_insn (insn);
1770 /* First see if the condition code mode alone if enough to say we can
1771 reverse the condition. If not, then search backwards for a set of
1772 ARG0. We do not need to check for an insn clobbering it since valid
1773 code will contain set a set with no intervening clobber. But
1774 stop when we reach a label. */
1775 #ifdef REVERSIBLE_CC_MODE
1776 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
1777 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
1781 for (prev = prev_nonnote_insn (insn);
1782 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1783 prev = prev_nonnote_insn (prev))
1784 if ((set = single_set (prev)) != 0
1785 && rtx_equal_p (SET_DEST (set), arg0))
1787 arg0 = SET_SRC (set);
1789 if (GET_CODE (arg0) == COMPARE)
1790 arg0 = XEXP (arg0, 0);
1795 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
1796 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
1797 return (GET_CODE (arg0) == CONST_INT
1798 || (GET_MODE (arg0) != VOIDmode
1799 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
1800 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
1803 /* Given an rtx-code for a comparison, return the code for the negated
1804 comparison. If no such code exists, return UNKNOWN.
1806 WATCH OUT! reverse_condition is not safe to use on a jump that might
1807 be acting on the results of an IEEE floating point comparison, because
1808 of the special treatment of non-signaling nans in comparisons.
1809 Use can_reverse_comparison_p to be sure. */
1812 reverse_condition (code)
1855 /* Similar, but we're allowed to generate unordered comparisons, which
1856 makes it safe for IEEE floating-point. Of course, we have to recognize
1857 that the target will support them too... */
1860 reverse_condition_maybe_unordered (code)
1863 /* Non-IEEE formats don't have unordered conditions. */
1864 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1865 return reverse_condition (code);
1911 /* Similar, but return the code when two operands of a comparison are swapped.
1912 This IS safe for IEEE floating-point. */
1915 swap_condition (code)
1958 /* Given a comparison CODE, return the corresponding unsigned comparison.
1959 If CODE is an equality comparison or already an unsigned comparison,
1960 CODE is returned. */
1963 unsigned_condition (code)
1990 /* Similarly, return the signed version of a comparison. */
1993 signed_condition (code)
2020 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2021 truth of CODE1 implies the truth of CODE2. */
2024 comparison_dominates_p (code1, code2)
2025 enum rtx_code code1, code2;
2033 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2034 || code2 == ORDERED)
2039 if (code2 == LE || code2 == NE || code2 == ORDERED)
2044 if (code2 == GE || code2 == NE || code2 == ORDERED)
2050 if (code2 == ORDERED)
2055 if (code2 == NE || code2 == ORDERED)
2060 if (code2 == LEU || code2 == NE)
2065 if (code2 == GEU || code2 == NE)
2081 /* Return 1 if INSN is an unconditional jump and nothing else. */
2087 return (GET_CODE (insn) == JUMP_INSN
2088 && GET_CODE (PATTERN (insn)) == SET
2089 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2090 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2093 /* Return nonzero if INSN is a (possibly) conditional jump
2096 Use this function is deprecated, since we need to support combined
2097 branch and compare insns. Use any_condjump_p instead whenever possible. */
2103 register rtx x = PATTERN (insn);
2105 if (GET_CODE (x) != SET
2106 || GET_CODE (SET_DEST (x)) != PC)
2110 if (GET_CODE (x) == LABEL_REF)
2112 else return (GET_CODE (x) == IF_THEN_ELSE
2113 && ((GET_CODE (XEXP (x, 2)) == PC
2114 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2115 || GET_CODE (XEXP (x, 1)) == RETURN))
2116 || (GET_CODE (XEXP (x, 1)) == PC
2117 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2118 || GET_CODE (XEXP (x, 2)) == RETURN))));
2123 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2126 Use this function is deprecated, since we need to support combined
2127 branch and compare insns. Use any_condjump_p instead whenever possible. */
2130 condjump_in_parallel_p (insn)
2133 register rtx x = PATTERN (insn);
2135 if (GET_CODE (x) != PARALLEL)
2138 x = XVECEXP (x, 0, 0);
2140 if (GET_CODE (x) != SET)
2142 if (GET_CODE (SET_DEST (x)) != PC)
2144 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2146 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2148 if (XEXP (SET_SRC (x), 2) == pc_rtx
2149 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2150 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2152 if (XEXP (SET_SRC (x), 1) == pc_rtx
2153 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2154 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2159 /* Return set of PC, otherwise NULL. */
2166 if (GET_CODE (insn) != JUMP_INSN)
2168 pat = PATTERN (insn);
2170 /* The set is allowed to appear either as the insn pattern or
2171 the first set in a PARALLEL. */
2172 if (GET_CODE (pat) == PARALLEL)
2173 pat = XVECEXP (pat, 0, 0);
2174 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2180 /* Return true when insn is an unconditional direct jump,
2181 possibly bundled inside a PARALLEL. */
2184 any_uncondjump_p (insn)
2187 rtx x = pc_set (insn);
2190 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2195 /* Return true when insn is a conditional jump. This function works for
2196 instructions containing PC sets in PARALLELs. The instruction may have
2197 various other effects so before removing the jump you must verify
2198 safe_to_remove_jump_p.
2200 Note that unlike condjump_p it returns false for unconditional jumps. */
2203 any_condjump_p (insn)
2206 rtx x = pc_set (insn);
2211 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2214 a = GET_CODE (XEXP (SET_SRC (x), 1));
2215 b = GET_CODE (XEXP (SET_SRC (x), 2));
2217 return ((b == PC && (a == LABEL_REF || a == RETURN))
2218 || (a == PC && (b == LABEL_REF || b == RETURN)));
2221 /* Return the label of a conditional jump. */
2224 condjump_label (insn)
2227 rtx x = pc_set (insn);
2232 if (GET_CODE (x) == LABEL_REF)
2234 if (GET_CODE (x) != IF_THEN_ELSE)
2236 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2238 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2243 /* Return true if INSN is a (possibly conditional) return insn. */
2246 returnjump_p_1 (loc, data)
2248 void *data ATTRIBUTE_UNUSED;
2251 return x && GET_CODE (x) == RETURN;
2258 if (GET_CODE (insn) != JUMP_INSN)
2260 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2263 /* Return true if INSN is a jump that only transfers control and
2272 if (GET_CODE (insn) != JUMP_INSN)
2275 set = single_set (insn);
2278 if (GET_CODE (SET_DEST (set)) != PC)
2280 if (side_effects_p (SET_SRC (set)))
2288 /* Return 1 if X is an RTX that does nothing but set the condition codes
2289 and CLOBBER or USE registers.
2290 Return -1 if X does explicitly set the condition codes,
2291 but also does other things. */
2295 rtx x ATTRIBUTE_UNUSED;
2297 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2299 if (GET_CODE (x) == PARALLEL)
2303 int other_things = 0;
2304 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2306 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2307 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2309 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2312 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2318 /* Follow any unconditional jump at LABEL;
2319 return the ultimate label reached by any such chain of jumps.
2320 If LABEL is not followed by a jump, return LABEL.
2321 If the chain loops or we can't find end, return LABEL,
2322 since that tells caller to avoid changing the insn.
2324 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2325 a USE or CLOBBER. */
2328 follow_jumps (label)
2333 register rtx value = label;
2338 && (insn = next_active_insn (value)) != 0
2339 && GET_CODE (insn) == JUMP_INSN
2340 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2341 || GET_CODE (PATTERN (insn)) == RETURN)
2342 && (next = NEXT_INSN (insn))
2343 && GET_CODE (next) == BARRIER);
2346 /* Don't chain through the insn that jumps into a loop
2347 from outside the loop,
2348 since that would create multiple loop entry jumps
2349 and prevent loop optimization. */
2351 if (!reload_completed)
2352 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2353 if (GET_CODE (tem) == NOTE
2354 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2355 /* ??? Optional. Disables some optimizations, but makes
2356 gcov output more accurate with -O. */
2357 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2360 /* If we have found a cycle, make the insn jump to itself. */
2361 if (JUMP_LABEL (insn) == label)
2364 tem = next_active_insn (JUMP_LABEL (insn));
2365 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2366 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2369 value = JUMP_LABEL (insn);
2376 /* Assuming that field IDX of X is a vector of label_refs,
2377 replace each of them by the ultimate label reached by it.
2378 Return nonzero if a change is made.
2379 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2382 tension_vector_labels (x, idx)
2388 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2390 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2391 register rtx nlabel = follow_jumps (olabel);
2392 if (nlabel && nlabel != olabel)
2394 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2395 ++LABEL_NUSES (nlabel);
2396 if (--LABEL_NUSES (olabel) == 0)
2397 delete_insn (olabel);
2404 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2405 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2406 in INSN, then store one of them in JUMP_LABEL (INSN).
2407 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2408 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2409 Also, when there are consecutive labels, canonicalize on the last of them.
2411 Note that two labels separated by a loop-beginning note
2412 must be kept distinct if we have not yet done loop-optimization,
2413 because the gap between them is where loop-optimize
2414 will want to move invariant code to. CROSS_JUMP tells us
2415 that loop-optimization is done with.
2417 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2418 two labels distinct if they are separated by only USE or CLOBBER insns. */
2421 mark_jump_label (x, insn, cross_jump, in_mem)
2427 register RTX_CODE code = GET_CODE (x);
2429 register const char *fmt;
2451 /* If this is a constant-pool reference, see if it is a label. */
2452 if (CONSTANT_POOL_ADDRESS_P (x))
2453 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2458 rtx label = XEXP (x, 0);
2463 /* Ignore remaining references to unreachable labels that
2464 have been deleted. */
2465 if (GET_CODE (label) == NOTE
2466 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2469 if (GET_CODE (label) != CODE_LABEL)
2472 /* Ignore references to labels of containing functions. */
2473 if (LABEL_REF_NONLOCAL_P (x))
2476 /* If there are other labels following this one,
2477 replace it with the last of the consecutive labels. */
2478 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2480 if (GET_CODE (next) == CODE_LABEL)
2482 else if (cross_jump && GET_CODE (next) == INSN
2483 && (GET_CODE (PATTERN (next)) == USE
2484 || GET_CODE (PATTERN (next)) == CLOBBER))
2486 else if (GET_CODE (next) != NOTE)
2488 else if (! cross_jump
2489 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2490 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2491 /* ??? Optional. Disables some optimizations, but
2492 makes gcov output more accurate with -O. */
2493 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
2497 XEXP (x, 0) = label;
2498 if (! insn || ! INSN_DELETED_P (insn))
2499 ++LABEL_NUSES (label);
2503 if (GET_CODE (insn) == JUMP_INSN)
2504 JUMP_LABEL (insn) = label;
2506 /* If we've changed OLABEL and we had a REG_LABEL note
2507 for it, update it as well. */
2508 else if (label != olabel
2509 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2510 XEXP (note, 0) = label;
2512 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2514 else if (! find_reg_note (insn, REG_LABEL, label))
2516 /* This code used to ignore labels which refered to dispatch
2517 tables to avoid flow.c generating worse code.
2519 However, in the presense of global optimizations like
2520 gcse which call find_basic_blocks without calling
2521 life_analysis, not recording such labels will lead
2522 to compiler aborts because of inconsistencies in the
2523 flow graph. So we go ahead and record the label.
2525 It may also be the case that the optimization argument
2526 is no longer valid because of the more accurate cfg
2527 we build in find_basic_blocks -- it no longer pessimizes
2528 code when it finds a REG_LABEL note. */
2529 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2536 /* Do walk the labels in a vector, but not the first operand of an
2537 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2540 if (! INSN_DELETED_P (insn))
2542 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2544 for (i = 0; i < XVECLEN (x, eltnum); i++)
2545 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2546 cross_jump, in_mem);
2554 fmt = GET_RTX_FORMAT (code);
2555 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2558 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2559 else if (fmt[i] == 'E')
2562 for (j = 0; j < XVECLEN (x, i); j++)
2563 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2568 /* If all INSN does is set the pc, delete it,
2569 and delete the insn that set the condition codes for it
2570 if that's what the previous thing was. */
2576 register rtx set = single_set (insn);
2578 if (set && GET_CODE (SET_DEST (set)) == PC)
2579 delete_computation (insn);
2582 /* Verify INSN is a BARRIER and delete it. */
2585 delete_barrier (insn)
2588 if (GET_CODE (insn) != BARRIER)
2594 /* Recursively delete prior insns that compute the value (used only by INSN
2595 which the caller is deleting) stored in the register mentioned by NOTE
2596 which is a REG_DEAD note associated with INSN. */
2599 delete_prior_computation (note, insn)
2604 rtx reg = XEXP (note, 0);
2606 for (our_prev = prev_nonnote_insn (insn);
2607 our_prev && (GET_CODE (our_prev) == INSN
2608 || GET_CODE (our_prev) == CALL_INSN);
2609 our_prev = prev_nonnote_insn (our_prev))
2611 rtx pat = PATTERN (our_prev);
2613 /* If we reach a CALL which is not calling a const function
2614 or the callee pops the arguments, then give up. */
2615 if (GET_CODE (our_prev) == CALL_INSN
2616 && (! CONST_CALL_P (our_prev)
2617 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2620 /* If we reach a SEQUENCE, it is too complex to try to
2621 do anything with it, so give up. */
2622 if (GET_CODE (pat) == SEQUENCE)
2625 if (GET_CODE (pat) == USE
2626 && GET_CODE (XEXP (pat, 0)) == INSN)
2627 /* reorg creates USEs that look like this. We leave them
2628 alone because reorg needs them for its own purposes. */
2631 if (reg_set_p (reg, pat))
2633 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2636 if (GET_CODE (pat) == PARALLEL)
2638 /* If we find a SET of something else, we can't
2643 for (i = 0; i < XVECLEN (pat, 0); i++)
2645 rtx part = XVECEXP (pat, 0, i);
2647 if (GET_CODE (part) == SET
2648 && SET_DEST (part) != reg)
2652 if (i == XVECLEN (pat, 0))
2653 delete_computation (our_prev);
2655 else if (GET_CODE (pat) == SET
2656 && GET_CODE (SET_DEST (pat)) == REG)
2658 int dest_regno = REGNO (SET_DEST (pat));
2660 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
2661 ? HARD_REGNO_NREGS (dest_regno,
2662 GET_MODE (SET_DEST (pat))) : 1);
2663 int regno = REGNO (reg);
2664 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
2665 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
2667 if (dest_regno >= regno
2668 && dest_endregno <= endregno)
2669 delete_computation (our_prev);
2671 /* We may have a multi-word hard register and some, but not
2672 all, of the words of the register are needed in subsequent
2673 insns. Write REG_UNUSED notes for those parts that were not
2675 else if (dest_regno <= regno
2676 && dest_endregno >= endregno)
2680 REG_NOTES (our_prev)
2681 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
2683 for (i = dest_regno; i < dest_endregno; i++)
2684 if (! find_regno_note (our_prev, REG_UNUSED, i))
2687 if (i == dest_endregno)
2688 delete_computation (our_prev);
2695 /* If PAT references the register that dies here, it is an
2696 additional use. Hence any prior SET isn't dead. However, this
2697 insn becomes the new place for the REG_DEAD note. */
2698 if (reg_overlap_mentioned_p (reg, pat))
2700 XEXP (note, 1) = REG_NOTES (our_prev);
2701 REG_NOTES (our_prev) = note;
2707 /* Delete INSN and recursively delete insns that compute values used only
2708 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2709 If we are running before flow.c, we need do nothing since flow.c will
2710 delete dead code. We also can't know if the registers being used are
2711 dead or not at this point.
2713 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2714 nothing other than set a register that dies in this insn, we can delete
2717 On machines with CC0, if CC0 is used in this insn, we may be able to
2718 delete the insn that set it. */
2721 delete_computation (insn)
2728 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2730 rtx prev = prev_nonnote_insn (insn);
2731 /* We assume that at this stage
2732 CC's are always set explicitly
2733 and always immediately before the jump that
2734 will use them. So if the previous insn
2735 exists to set the CC's, delete it
2736 (unless it performs auto-increments, etc.). */
2737 if (prev && GET_CODE (prev) == INSN
2738 && sets_cc0_p (PATTERN (prev)))
2740 if (sets_cc0_p (PATTERN (prev)) > 0
2741 && ! side_effects_p (PATTERN (prev)))
2742 delete_computation (prev);
2744 /* Otherwise, show that cc0 won't be used. */
2745 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2746 cc0_rtx, REG_NOTES (prev));
2751 #ifdef INSN_SCHEDULING
2752 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
2753 reload has completed. The schedulers need to be fixed. Until
2754 they are, we must not rely on the death notes here. */
2755 if (reload_completed && flag_schedule_insns_after_reload)
2762 /* The REG_DEAD note may have been omitted for a register
2763 which is both set and used by the insn. */
2764 set = single_set (insn);
2765 if (set && GET_CODE (SET_DEST (set)) == REG)
2767 int dest_regno = REGNO (SET_DEST (set));
2769 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
2770 ? HARD_REGNO_NREGS (dest_regno,
2771 GET_MODE (SET_DEST (set))) : 1);
2774 for (i = dest_regno; i < dest_endregno; i++)
2776 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
2777 || find_regno_note (insn, REG_DEAD, i))
2780 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
2781 ? gen_rtx_REG (reg_raw_mode[i], i)
2782 : SET_DEST (set)), NULL_RTX);
2783 delete_prior_computation (note, insn);
2787 for (note = REG_NOTES (insn); note; note = next)
2789 next = XEXP (note, 1);
2791 if (REG_NOTE_KIND (note) != REG_DEAD
2792 /* Verify that the REG_NOTE is legitimate. */
2793 || GET_CODE (XEXP (note, 0)) != REG)
2796 delete_prior_computation (note, insn);
2802 /* Delete insn INSN from the chain of insns and update label ref counts.
2803 May delete some following insns as a consequence; may even delete
2804 a label elsewhere and insns that follow it.
2806 Returns the first insn after INSN that was not deleted. */
2812 register rtx next = NEXT_INSN (insn);
2813 register rtx prev = PREV_INSN (insn);
2814 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2815 register int dont_really_delete = 0;
2817 while (next && INSN_DELETED_P (next))
2818 next = NEXT_INSN (next);
2820 /* This insn is already deleted => return first following nondeleted. */
2821 if (INSN_DELETED_P (insn))
2825 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2827 /* Don't delete user-declared labels. When optimizing, convert them
2828 to special NOTEs instead. When not optimizing, leave them alone. */
2829 if (was_code_label && LABEL_NAME (insn) != 0)
2832 dont_really_delete = 1;
2833 else if (! dont_really_delete)
2835 const char *name = LABEL_NAME (insn);
2836 PUT_CODE (insn, NOTE);
2837 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2838 NOTE_SOURCE_FILE (insn) = name;
2839 dont_really_delete = 1;
2843 /* Mark this insn as deleted. */
2844 INSN_DELETED_P (insn) = 1;
2846 /* If this is an unconditional jump, delete it from the jump chain. */
2847 if (simplejump_p (insn))
2848 delete_from_jump_chain (insn);
2850 /* If instruction is followed by a barrier,
2851 delete the barrier too. */
2853 if (next != 0 && GET_CODE (next) == BARRIER)
2855 INSN_DELETED_P (next) = 1;
2856 next = NEXT_INSN (next);
2859 /* Patch out INSN (and the barrier if any) */
2861 if (! dont_really_delete)
2865 NEXT_INSN (prev) = next;
2866 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2867 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2868 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2873 PREV_INSN (next) = prev;
2874 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2875 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2878 if (prev && NEXT_INSN (prev) == 0)
2879 set_last_insn (prev);
2882 /* If deleting a jump, decrement the count of the label,
2883 and delete the label if it is now unused. */
2885 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2887 rtx lab = JUMP_LABEL (insn), lab_next;
2889 if (--LABEL_NUSES (lab) == 0)
2891 /* This can delete NEXT or PREV,
2892 either directly if NEXT is JUMP_LABEL (INSN),
2893 or indirectly through more levels of jumps. */
2896 /* I feel a little doubtful about this loop,
2897 but I see no clean and sure alternative way
2898 to find the first insn after INSN that is not now deleted.
2899 I hope this works. */
2900 while (next && INSN_DELETED_P (next))
2901 next = NEXT_INSN (next);
2904 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2905 && GET_CODE (lab_next) == JUMP_INSN
2906 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2907 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2909 /* If we're deleting the tablejump, delete the dispatch table.
2910 We may not be able to kill the label immediately preceeding
2911 just yet, as it might be referenced in code leading up to
2913 delete_insn (lab_next);
2917 /* Likewise if we're deleting a dispatch table. */
2919 if (GET_CODE (insn) == JUMP_INSN
2920 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2921 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2923 rtx pat = PATTERN (insn);
2924 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2925 int len = XVECLEN (pat, diff_vec_p);
2927 for (i = 0; i < len; i++)
2928 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2929 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2930 while (next && INSN_DELETED_P (next))
2931 next = NEXT_INSN (next);
2935 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2936 prev = PREV_INSN (prev);
2938 /* If INSN was a label and a dispatch table follows it,
2939 delete the dispatch table. The tablejump must have gone already.
2940 It isn't useful to fall through into a table. */
2943 && NEXT_INSN (insn) != 0
2944 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2945 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2946 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2947 next = delete_insn (NEXT_INSN (insn));
2949 /* If INSN was a label, delete insns following it if now unreachable. */
2951 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2953 register RTX_CODE code;
2955 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2956 || code == NOTE || code == BARRIER
2957 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2960 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
2961 next = NEXT_INSN (next);
2962 /* Keep going past other deleted labels to delete what follows. */
2963 else if (code == CODE_LABEL && INSN_DELETED_P (next))
2964 next = NEXT_INSN (next);
2966 /* Note: if this deletes a jump, it can cause more
2967 deletion of unreachable code, after a different label.
2968 As long as the value from this recursive call is correct,
2969 this invocation functions correctly. */
2970 next = delete_insn (next);
2977 /* Advance from INSN till reaching something not deleted
2978 then return that. May return INSN itself. */
2981 next_nondeleted_insn (insn)
2984 while (INSN_DELETED_P (insn))
2985 insn = NEXT_INSN (insn);
2989 /* Delete a range of insns from FROM to TO, inclusive.
2990 This is for the sake of peephole optimization, so assume
2991 that whatever these insns do will still be done by a new
2992 peephole insn that will replace them. */
2995 delete_for_peephole (from, to)
2996 register rtx from, to;
2998 register rtx insn = from;
3002 register rtx next = NEXT_INSN (insn);
3003 register rtx prev = PREV_INSN (insn);
3005 if (GET_CODE (insn) != NOTE)
3007 INSN_DELETED_P (insn) = 1;
3009 /* Patch this insn out of the chain. */
3010 /* We don't do this all at once, because we
3011 must preserve all NOTEs. */
3013 NEXT_INSN (prev) = next;
3016 PREV_INSN (next) = prev;
3024 /* Note that if TO is an unconditional jump
3025 we *do not* delete the BARRIER that follows,
3026 since the peephole that replaces this sequence
3027 is also an unconditional jump in that case. */
3030 /* We have determined that INSN is never reached, and are about to
3031 delete it. Print a warning if the user asked for one.
3033 To try to make this warning more useful, this should only be called
3034 once per basic block not reached, and it only warns when the basic
3035 block contains more than one line from the current function, and
3036 contains at least one operation. CSE and inlining can duplicate insns,
3037 so it's possible to get spurious warnings from this. */
3040 never_reached_warning (avoided_insn)
3044 rtx a_line_note = NULL;
3045 int two_avoided_lines = 0;
3046 int contains_insn = 0;
3048 if (! warn_notreached)
3051 /* Scan forwards, looking at LINE_NUMBER notes, until
3052 we hit a LABEL or we run out of insns. */
3054 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3056 if (GET_CODE (insn) == CODE_LABEL)
3058 else if (GET_CODE (insn) == NOTE /* A line number note? */
3059 && NOTE_LINE_NUMBER (insn) >= 0)
3061 if (a_line_note == NULL)
3064 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3065 != NOTE_LINE_NUMBER (insn));
3067 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
3070 if (two_avoided_lines && contains_insn)
3071 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3072 NOTE_LINE_NUMBER (a_line_note),
3073 "will never be executed");
3076 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3077 NLABEL as a return. Accrue modifications into the change group. */
3080 redirect_exp_1 (loc, olabel, nlabel, insn)
3085 register rtx x = *loc;
3086 register RTX_CODE code = GET_CODE (x);
3088 register const char *fmt;
3090 if (code == LABEL_REF)
3092 if (XEXP (x, 0) == olabel)
3096 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3098 n = gen_rtx_RETURN (VOIDmode);
3100 validate_change (insn, loc, n, 1);
3104 else if (code == RETURN && olabel == 0)
3106 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3107 if (loc == &PATTERN (insn))
3108 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3109 validate_change (insn, loc, x, 1);
3113 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3114 && GET_CODE (SET_SRC (x)) == LABEL_REF
3115 && XEXP (SET_SRC (x), 0) == olabel)
3117 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3121 fmt = GET_RTX_FORMAT (code);
3122 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3125 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3126 else if (fmt[i] == 'E')
3129 for (j = 0; j < XVECLEN (x, i); j++)
3130 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3135 /* Similar, but apply the change group and report success or failure. */
3138 redirect_exp (loc, olabel, nlabel, insn)
3143 redirect_exp_1 (loc, olabel, nlabel, insn);
3144 if (num_validated_changes () == 0)
3147 return apply_change_group ();
3150 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3151 the modifications into the change group. Return false if we did
3152 not see how to do that. */
3155 redirect_jump_1 (jump, nlabel)
3158 int ochanges = num_validated_changes ();
3159 redirect_exp_1 (&PATTERN (jump), JUMP_LABEL (jump), nlabel, jump);
3160 return num_validated_changes () > ochanges;
3163 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3164 jump target label is unused as a result, it and the code following
3167 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3170 The return value will be 1 if the change was made, 0 if it wasn't
3171 (this can only occur for NLABEL == 0). */
3174 redirect_jump (jump, nlabel)
3177 register rtx olabel = JUMP_LABEL (jump);
3179 if (nlabel == olabel)
3182 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
3185 /* If this is an unconditional branch, delete it from the jump_chain of
3186 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3187 have UID's in range and JUMP_CHAIN is valid). */
3188 if (jump_chain && (simplejump_p (jump)
3189 || GET_CODE (PATTERN (jump)) == RETURN))
3191 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3193 delete_from_jump_chain (jump);
3194 if (label_index < max_jump_chain
3195 && INSN_UID (jump) < max_jump_chain)
3197 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3198 jump_chain[label_index] = jump;
3202 JUMP_LABEL (jump) = nlabel;
3204 ++LABEL_NUSES (nlabel);
3206 /* If we're eliding the jump over exception cleanups at the end of a
3207 function, move the function end note so that -Wreturn-type works. */
3208 if (olabel && NEXT_INSN (olabel)
3209 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3210 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3211 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3213 if (olabel && --LABEL_NUSES (olabel) == 0)
3214 delete_insn (olabel);
3219 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3220 Accrue the modifications into the change group. */
3223 invert_exp_1 (x, insn)
3227 register RTX_CODE code;
3229 register const char *fmt;
3231 code = GET_CODE (x);
3233 if (code == IF_THEN_ELSE)
3235 register rtx comp = XEXP (x, 0);
3238 /* We can do this in two ways: The preferable way, which can only
3239 be done if this is not an integer comparison, is to reverse
3240 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3241 of the IF_THEN_ELSE. If we can't do either, fail. */
3243 if (can_reverse_comparison_p (comp, insn))
3245 validate_change (insn, &XEXP (x, 0),
3246 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
3247 GET_MODE (comp), XEXP (comp, 0),
3254 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3255 validate_change (insn, &XEXP (x, 2), tem, 1);
3259 fmt = GET_RTX_FORMAT (code);
3260 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3263 invert_exp_1 (XEXP (x, i), insn);
3264 else if (fmt[i] == 'E')
3267 for (j = 0; j < XVECLEN (x, i); j++)
3268 invert_exp_1 (XVECEXP (x, i, j), insn);
3273 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3275 Return 1 if we can do so, 0 if we cannot find a way to do so that
3276 matches a pattern. */
3279 invert_exp (x, insn)
3283 invert_exp_1 (x, insn);
3284 if (num_validated_changes () == 0)
3287 return apply_change_group ();
3290 /* Invert the condition of the jump JUMP, and make it jump to label
3291 NLABEL instead of where it jumps now. Accrue changes into the
3292 change group. Return false if we didn't see how to perform the
3293 inversion and redirection. */
3296 invert_jump_1 (jump, nlabel)
3301 ochanges = num_validated_changes ();
3302 invert_exp_1 (PATTERN (jump), jump);
3303 if (num_validated_changes () == ochanges)
3306 return redirect_jump_1 (jump, nlabel);
3309 /* Invert the condition of the jump JUMP, and make it jump to label
3310 NLABEL instead of where it jumps now. Return true if successful. */
3313 invert_jump (jump, nlabel)
3316 /* We have to either invert the condition and change the label or
3317 do neither. Either operation could fail. We first try to invert
3318 the jump. If that succeeds, we try changing the label. If that fails,
3319 we invert the jump back to what it was. */
3321 if (! invert_exp (PATTERN (jump), jump))
3324 if (redirect_jump (jump, nlabel))
3326 /* An inverted jump means that a probability taken becomes a
3327 probability not taken. Subtract the branch probability from the
3328 probability base to convert it back to a taken probability. */
3330 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3332 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3337 if (! invert_exp (PATTERN (jump), jump))
3338 /* This should just be putting it back the way it was. */
3344 /* Delete the instruction JUMP from any jump chain it might be on. */
3347 delete_from_jump_chain (jump)
3351 rtx olabel = JUMP_LABEL (jump);
3353 /* Handle unconditional jumps. */
3354 if (jump_chain && olabel != 0
3355 && INSN_UID (olabel) < max_jump_chain
3356 && simplejump_p (jump))
3357 index = INSN_UID (olabel);
3358 /* Handle return insns. */
3359 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3363 if (jump_chain[index] == jump)
3364 jump_chain[index] = jump_chain[INSN_UID (jump)];
3369 for (insn = jump_chain[index];
3371 insn = jump_chain[INSN_UID (insn)])
3372 if (jump_chain[INSN_UID (insn)] == jump)
3374 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3380 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3382 If the old jump target label (before the dispatch table) becomes unused,
3383 it and the dispatch table may be deleted. In that case, find the insn
3384 before the jump references that label and delete it and logical successors
3388 redirect_tablejump (jump, nlabel)
3391 register rtx olabel = JUMP_LABEL (jump);
3393 /* Add this jump to the jump_chain of NLABEL. */
3394 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3395 && INSN_UID (jump) < max_jump_chain)
3397 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3398 jump_chain[INSN_UID (nlabel)] = jump;
3401 PATTERN (jump) = gen_jump (nlabel);
3402 JUMP_LABEL (jump) = nlabel;
3403 ++LABEL_NUSES (nlabel);
3404 INSN_CODE (jump) = -1;
3406 if (--LABEL_NUSES (olabel) == 0)
3408 delete_labelref_insn (jump, olabel, 0);
3409 delete_insn (olabel);
3413 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3414 If we found one, delete it and then delete this insn if DELETE_THIS is
3415 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3418 delete_labelref_insn (insn, label, delete_this)
3425 if (GET_CODE (insn) != NOTE
3426 && reg_mentioned_p (label, PATTERN (insn)))
3437 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3438 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3452 /* Like rtx_equal_p except that it considers two REGs as equal
3453 if they renumber to the same value and considers two commutative
3454 operations to be the same if the order of the operands has been
3457 ??? Addition is not commutative on the PA due to the weird implicit
3458 space register selection rules for memory addresses. Therefore, we
3459 don't consider a + b == b + a.
3461 We could/should make this test a little tighter. Possibly only
3462 disabling it on the PA via some backend macro or only disabling this
3463 case when the PLUS is inside a MEM. */
3466 rtx_renumbered_equal_p (x, y)
3470 register RTX_CODE code = GET_CODE (x);
3471 register const char *fmt;
3476 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3477 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3478 && GET_CODE (SUBREG_REG (y)) == REG)))
3480 int reg_x = -1, reg_y = -1;
3481 int word_x = 0, word_y = 0;
3483 if (GET_MODE (x) != GET_MODE (y))
3486 /* If we haven't done any renumbering, don't
3487 make any assumptions. */
3488 if (reg_renumber == 0)
3489 return rtx_equal_p (x, y);
3493 reg_x = REGNO (SUBREG_REG (x));
3494 word_x = SUBREG_WORD (x);
3496 if (reg_renumber[reg_x] >= 0)
3498 reg_x = reg_renumber[reg_x] + word_x;
3506 if (reg_renumber[reg_x] >= 0)
3507 reg_x = reg_renumber[reg_x];
3510 if (GET_CODE (y) == SUBREG)
3512 reg_y = REGNO (SUBREG_REG (y));
3513 word_y = SUBREG_WORD (y);
3515 if (reg_renumber[reg_y] >= 0)
3517 reg_y = reg_renumber[reg_y];
3525 if (reg_renumber[reg_y] >= 0)
3526 reg_y = reg_renumber[reg_y];
3529 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
3532 /* Now we have disposed of all the cases
3533 in which different rtx codes can match. */
3534 if (code != GET_CODE (y))
3546 return INTVAL (x) == INTVAL (y);
3549 /* We can't assume nonlocal labels have their following insns yet. */
3550 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3551 return XEXP (x, 0) == XEXP (y, 0);
3553 /* Two label-refs are equivalent if they point at labels
3554 in the same position in the instruction stream. */
3555 return (next_real_insn (XEXP (x, 0))
3556 == next_real_insn (XEXP (y, 0)));
3559 return XSTR (x, 0) == XSTR (y, 0);
3562 /* If we didn't match EQ equality above, they aren't the same. */
3569 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3571 if (GET_MODE (x) != GET_MODE (y))
3574 /* For commutative operations, the RTX match if the operand match in any
3575 order. Also handle the simple binary and unary cases without a loop.
3577 ??? Don't consider PLUS a commutative operator; see comments above. */
3578 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3580 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3581 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3582 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3583 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3584 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3585 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3586 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3587 else if (GET_RTX_CLASS (code) == '1')
3588 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3590 /* Compare the elements. If any pair of corresponding elements
3591 fail to match, return 0 for the whole things. */
3593 fmt = GET_RTX_FORMAT (code);
3594 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3600 if (XWINT (x, i) != XWINT (y, i))
3605 if (XINT (x, i) != XINT (y, i))
3610 if (strcmp (XSTR (x, i), XSTR (y, i)))
3615 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3620 if (XEXP (x, i) != XEXP (y, i))
3627 if (XVECLEN (x, i) != XVECLEN (y, i))
3629 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3630 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3641 /* If X is a hard register or equivalent to one or a subregister of one,
3642 return the hard register number. If X is a pseudo register that was not
3643 assigned a hard register, return the pseudo register number. Otherwise,
3644 return -1. Any rtx is valid for X. */
3650 if (GET_CODE (x) == REG)
3652 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3653 return reg_renumber[REGNO (x)];
3656 if (GET_CODE (x) == SUBREG)
3658 int base = true_regnum (SUBREG_REG (x));
3659 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3660 return SUBREG_WORD (x) + base;
3665 /* Optimize code of the form:
3667 for (x = a[i]; x; ...)
3669 for (x = a[i]; x; ...)
3673 Loop optimize will change the above code into
3677 { ...; if (! (x = ...)) break; }
3680 { ...; if (! (x = ...)) break; }
3683 In general, if the first test fails, the program can branch
3684 directly to `foo' and skip the second try which is doomed to fail.
3685 We run this after loop optimization and before flow analysis. */
3687 /* When comparing the insn patterns, we track the fact that different
3688 pseudo-register numbers may have been used in each computation.
3689 The following array stores an equivalence -- same_regs[I] == J means
3690 that pseudo register I was used in the first set of tests in a context
3691 where J was used in the second set. We also count the number of such
3692 pending equivalences. If nonzero, the expressions really aren't the
3695 static int *same_regs;
3697 static int num_same_regs;
3699 /* Track any registers modified between the target of the first jump and
3700 the second jump. They never compare equal. */
3702 static char *modified_regs;
3704 /* Record if memory was modified. */
3706 static int modified_mem;
3708 /* Called via note_stores on each insn between the target of the first
3709 branch and the second branch. It marks any changed registers. */
3712 mark_modified_reg (dest, x, data)
3714 rtx x ATTRIBUTE_UNUSED;
3715 void *data ATTRIBUTE_UNUSED;
3720 if (GET_CODE (dest) == SUBREG)
3721 dest = SUBREG_REG (dest);
3723 if (GET_CODE (dest) == MEM)
3726 if (GET_CODE (dest) != REG)
3729 regno = REGNO (dest);
3730 if (regno >= FIRST_PSEUDO_REGISTER)
3731 modified_regs[regno] = 1;
3733 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3734 modified_regs[regno + i] = 1;
3737 /* F is the first insn in the chain of insns. */
3740 thread_jumps (f, max_reg, flag_before_loop)
3743 int flag_before_loop;
3745 /* Basic algorithm is to find a conditional branch,
3746 the label it may branch to, and the branch after
3747 that label. If the two branches test the same condition,
3748 walk back from both branch paths until the insn patterns
3749 differ, or code labels are hit. If we make it back to
3750 the target of the first branch, then we know that the first branch
3751 will either always succeed or always fail depending on the relative
3752 senses of the two branches. So adjust the first branch accordingly
3755 rtx label, b1, b2, t1, t2;
3756 enum rtx_code code1, code2;
3757 rtx b1op0, b1op1, b2op0, b2op1;
3762 /* Allocate register tables and quick-reset table. */
3763 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3764 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3765 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3766 for (i = 0; i < max_reg; i++)
3773 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3775 /* Get to a candidate branch insn. */
3776 if (GET_CODE (b1) != JUMP_INSN
3777 || ! condjump_p (b1) || simplejump_p (b1)
3778 || JUMP_LABEL (b1) == 0)
3781 bzero (modified_regs, max_reg * sizeof (char));
3784 bcopy ((char *) all_reset, (char *) same_regs,
3785 max_reg * sizeof (int));
3788 label = JUMP_LABEL (b1);
3790 /* Look for a branch after the target. Record any registers and
3791 memory modified between the target and the branch. Stop when we
3792 get to a label since we can't know what was changed there. */
3793 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3795 if (GET_CODE (b2) == CODE_LABEL)
3798 else if (GET_CODE (b2) == JUMP_INSN)
3800 /* If this is an unconditional jump and is the only use of
3801 its target label, we can follow it. */
3802 if (simplejump_p (b2)
3803 && JUMP_LABEL (b2) != 0
3804 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3806 b2 = JUMP_LABEL (b2);
3813 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3816 if (GET_CODE (b2) == CALL_INSN)
3819 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3820 if (call_used_regs[i] && ! fixed_regs[i]
3821 && i != STACK_POINTER_REGNUM
3822 && i != FRAME_POINTER_REGNUM
3823 && i != HARD_FRAME_POINTER_REGNUM
3824 && i != ARG_POINTER_REGNUM)
3825 modified_regs[i] = 1;
3828 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3831 /* Check the next candidate branch insn from the label
3834 || GET_CODE (b2) != JUMP_INSN
3836 || ! condjump_p (b2)
3837 || simplejump_p (b2))
3840 /* Get the comparison codes and operands, reversing the
3841 codes if appropriate. If we don't have comparison codes,
3842 we can't do anything. */
3843 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
3844 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
3845 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
3846 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
3847 code1 = reverse_condition (code1);
3849 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
3850 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
3851 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
3852 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
3853 code2 = reverse_condition (code2);
3855 /* If they test the same things and knowing that B1 branches
3856 tells us whether or not B2 branches, check if we
3857 can thread the branch. */
3858 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3859 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3860 && (comparison_dominates_p (code1, code2)
3861 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
3864 && comparison_dominates_p (code1, reverse_condition (code2)))))
3867 t1 = prev_nonnote_insn (b1);
3868 t2 = prev_nonnote_insn (b2);
3870 while (t1 != 0 && t2 != 0)
3874 /* We have reached the target of the first branch.
3875 If there are no pending register equivalents,
3876 we know that this branch will either always
3877 succeed (if the senses of the two branches are
3878 the same) or always fail (if not). */
3881 if (num_same_regs != 0)
3884 if (comparison_dominates_p (code1, code2))
3885 new_label = JUMP_LABEL (b2);
3887 new_label = get_label_after (b2);
3889 if (JUMP_LABEL (b1) != new_label)
3891 rtx prev = PREV_INSN (new_label);
3893 if (flag_before_loop
3894 && GET_CODE (prev) == NOTE
3895 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3897 /* Don't thread to the loop label. If a loop
3898 label is reused, loop optimization will
3899 be disabled for that loop. */
3900 new_label = gen_label_rtx ();
3901 emit_label_after (new_label, PREV_INSN (prev));
3903 changed |= redirect_jump (b1, new_label);
3908 /* If either of these is not a normal insn (it might be
3909 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3910 have already been skipped above.) Similarly, fail
3911 if the insns are different. */
3912 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3913 || recog_memoized (t1) != recog_memoized (t2)
3914 || ! rtx_equal_for_thread_p (PATTERN (t1),
3918 t1 = prev_nonnote_insn (t1);
3919 t2 = prev_nonnote_insn (t2);
3926 free (modified_regs);
3931 /* This is like RTX_EQUAL_P except that it knows about our handling of
3932 possibly equivalent registers and knows to consider volatile and
3933 modified objects as not equal.
3935 YINSN is the insn containing Y. */
3938 rtx_equal_for_thread_p (x, y, yinsn)
3944 register enum rtx_code code;
3945 register const char *fmt;
3947 code = GET_CODE (x);
3948 /* Rtx's of different codes cannot be equal. */
3949 if (code != GET_CODE (y))
3952 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3953 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3955 if (GET_MODE (x) != GET_MODE (y))
3958 /* For floating-point, consider everything unequal. This is a bit
3959 pessimistic, but this pass would only rarely do anything for FP
3961 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3962 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
3965 /* For commutative operations, the RTX match if the operand match in any
3966 order. Also handle the simple binary and unary cases without a loop. */
3967 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3968 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3969 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
3970 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
3971 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
3972 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3973 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3974 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
3975 else if (GET_RTX_CLASS (code) == '1')
3976 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
3978 /* Handle special-cases first. */
3982 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
3985 /* If neither is user variable or hard register, check for possible
3987 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
3988 || REGNO (x) < FIRST_PSEUDO_REGISTER
3989 || REGNO (y) < FIRST_PSEUDO_REGISTER)
3992 if (same_regs[REGNO (x)] == -1)
3994 same_regs[REGNO (x)] = REGNO (y);
3997 /* If this is the first time we are seeing a register on the `Y'
3998 side, see if it is the last use. If not, we can't thread the
3999 jump, so mark it as not equivalent. */
4000 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4006 return (same_regs[REGNO (x)] == (int) REGNO (y));
4011 /* If memory modified or either volatile, not equivalent.
4012 Else, check address. */
4013 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4016 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4019 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4025 /* Cancel a pending `same_regs' if setting equivalenced registers.
4026 Then process source. */
4027 if (GET_CODE (SET_DEST (x)) == REG
4028 && GET_CODE (SET_DEST (y)) == REG)
4030 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4032 same_regs[REGNO (SET_DEST (x))] = -1;
4035 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4039 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4042 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4045 return XEXP (x, 0) == XEXP (y, 0);
4048 return XSTR (x, 0) == XSTR (y, 0);
4057 fmt = GET_RTX_FORMAT (code);
4058 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4063 if (XWINT (x, i) != XWINT (y, i))
4069 if (XINT (x, i) != XINT (y, i))
4075 /* Two vectors must have the same length. */
4076 if (XVECLEN (x, i) != XVECLEN (y, i))
4079 /* And the corresponding elements must match. */
4080 for (j = 0; j < XVECLEN (x, i); j++)
4081 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4082 XVECEXP (y, i, j), yinsn) == 0)
4087 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4093 if (strcmp (XSTR (x, i), XSTR (y, i)))
4098 /* These are just backpointers, so they don't matter. */
4105 /* It is believed that rtx's at this level will never
4106 contain anything but integers and other rtx's,
4107 except for within LABEL_REFs and SYMBOL_REFs. */