1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This is the jump-optimization pass of the compiler.
23 It is run two or three times: once before cse, sometimes once after cse,
24 and once after reload (before final).
26 jump_optimize deletes unreachable code and labels that are not used.
27 It also deletes jumps that jump to the following insn,
28 and simplifies jumps around unconditional jumps and jumps
29 to unconditional jumps.
31 Each CODE_LABEL has a count of the times it is used
32 stored in the LABEL_NUSES internal field, and each JUMP_INSN
33 has one label that it refers to stored in the
34 JUMP_LABEL internal field. With this we can detect labels that
35 become unused because of the deletion of all the jumps that
36 formerly used them. The JUMP_LABEL info is sometimes looked
39 Optionally, cross-jumping can be done. Currently it is done
40 only the last time (when after reload and before final).
41 In fact, the code for cross-jumping now assumes that register
42 allocation has been done, since it uses `rtx_renumbered_equal_p'.
44 Jump optimization is done after cse when cse's constant-propagation
45 causes jumps to become unconditional or to be deleted.
47 Unreachable loops are not detected here, because the labels
48 have references and the insns appear reachable from the labels.
49 find_basic_blocks in flow.c finds and deletes such loops.
51 The subroutines delete_insn, redirect_jump, and invert_jump are used
52 from other passes as well. */
59 #include "hard-reg-set.h"
61 #include "insn-config.h"
62 #include "insn-flags.h"
63 #include "insn-attr.h"
71 /* ??? Eventually must record somehow the labels used by jumps
72 from nested functions. */
73 /* Pre-record the next or previous real insn for each label?
74 No, this pass is very fast anyway. */
75 /* Condense consecutive labels?
76 This would make life analysis faster, maybe. */
77 /* Optimize jump y; x: ... y: jumpif... x?
78 Don't know if it is worth bothering with. */
79 /* Optimize two cases of conditional jump to conditional jump?
80 This can never delete any instruction or make anything dead,
81 or even change what is live at any point.
82 So perhaps let combiner do it. */
84 /* Vector indexed by uid.
85 For each CODE_LABEL, index by its uid to get first unconditional jump
86 that jumps to the label.
87 For each JUMP_INSN, index by its uid to get the next unconditional jump
88 that jumps to the same label.
89 Element 0 is the start of a chain of all return insns.
90 (It is safe to use element 0 because insn uid 0 is not used. */
92 static rtx *jump_chain;
94 /* Maximum index in jump_chain. */
96 static int max_jump_chain;
98 /* Set nonzero by jump_optimize if control can fall through
99 to the end of the function. */
102 /* Indicates whether death notes are significant in cross jump analysis.
103 Normally they are not significant, because of A and B jump to C,
104 and R dies in A, it must die in B. But this might not be true after
105 stack register conversion, and we must compare death notes in that
108 static int cross_jump_death_matters = 0;
110 static int init_label_info PROTO((rtx));
111 static void delete_barrier_successors PROTO((rtx));
112 static void mark_all_labels PROTO((rtx, int));
113 static rtx delete_unreferenced_labels PROTO((rtx));
114 static void delete_noop_moves PROTO((rtx));
115 static int calculate_can_reach_end PROTO((rtx, int, int));
116 static int duplicate_loop_exit_test PROTO((rtx));
117 static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *));
118 static void do_cross_jump PROTO((rtx, rtx, rtx));
119 static int jump_back_p PROTO((rtx, rtx));
120 static int tension_vector_labels PROTO((rtx, int));
121 static void mark_jump_label PROTO((rtx, rtx, int));
122 static void delete_computation PROTO((rtx));
123 static void delete_from_jump_chain PROTO((rtx));
124 static int delete_labelref_insn PROTO((rtx, rtx, int));
125 static void mark_modified_reg PROTO((rtx, rtx, void *));
126 static void redirect_tablejump PROTO((rtx, rtx));
127 static void jump_optimize_1 PROTO ((rtx, int, int, int, int));
128 #if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
129 static rtx find_insert_position PROTO((rtx, rtx));
131 static int returnjump_p_1 PROTO((rtx *, void *));
132 static void delete_prior_computation PROTO((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);
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);
157 /* Delete no-op jumps and optimize jumps to jumps
158 and jumps around jumps.
159 Delete unused labels and unreachable code.
161 If CROSS_JUMP is 1, detect matching code
162 before a jump and its destination and unify them.
163 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
165 If NOOP_MOVES is nonzero, delete no-op move insns.
167 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
168 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
170 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
171 and JUMP_LABEL field for jumping insns.
173 If `optimize' is zero, don't change any code,
174 just determine whether control drops off the end of the function.
175 This case occurs when we have -W and not -O.
176 It works because `delete_insn' checks the value of `optimize'
177 and refrains from actually deleting when that is 0. */
180 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
185 int mark_labels_only;
187 register rtx insn, next;
194 cross_jump_death_matters = (cross_jump == 2);
195 max_uid = init_label_info (f) + 1;
197 /* If we are performing cross jump optimizations, then initialize
198 tables mapping UIDs to EH regions to avoid incorrect movement
199 of insns from one EH region to another. */
200 if (flag_exceptions && cross_jump)
201 init_insn_eh_region (f, max_uid);
203 delete_barrier_successors (f);
205 /* Leave some extra room for labels and duplicate exit test insns
207 max_jump_chain = max_uid * 14 / 10;
208 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
210 mark_all_labels (f, cross_jump);
212 /* Keep track of labels used from static data;
213 they cannot ever be deleted. */
215 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
216 LABEL_NUSES (XEXP (insn, 0))++;
218 check_exception_handler_labels ();
220 /* Keep track of labels used for marking handlers for exception
221 regions; they cannot usually be deleted. */
223 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
224 LABEL_NUSES (XEXP (insn, 0))++;
226 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
227 notes and recompute LABEL_NUSES. */
228 if (mark_labels_only)
231 exception_optimize ();
233 last_insn = delete_unreferenced_labels (f);
237 /* CAN_REACH_END is persistent for each function. Once set it should
238 not be cleared. This is especially true for the case where we
239 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
240 the front-end before compiling each function. */
241 if (calculate_can_reach_end (last_insn, 1, 0))
244 /* Zero the "deleted" flag of all the "deleted" insns. */
245 for (insn = f; insn; insn = NEXT_INSN (insn))
246 INSN_DELETED_P (insn) = 0;
254 /* If we fall through to the epilogue, see if we can insert a RETURN insn
255 in front of it. If the machine allows it at this point (we might be
256 after reload for a leaf routine), it will improve optimization for it
258 insn = get_last_insn ();
259 while (insn && GET_CODE (insn) == NOTE)
260 insn = PREV_INSN (insn);
262 if (insn && GET_CODE (insn) != BARRIER)
264 emit_jump_insn (gen_return ());
271 delete_noop_moves (f);
273 /* If we haven't yet gotten to reload and we have just run regscan,
274 delete any insn that sets a register that isn't used elsewhere.
275 This helps some of the optimizations below by having less insns
276 being jumped around. */
278 if (! reload_completed && after_regscan)
279 for (insn = f; insn; insn = next)
281 rtx set = single_set (insn);
283 next = NEXT_INSN (insn);
285 if (set && GET_CODE (SET_DEST (set)) == REG
286 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
287 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
288 /* We use regno_last_note_uid so as not to delete the setting
289 of a reg that's used in notes. A subsequent optimization
290 might arrange to use that reg for real. */
291 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
292 && ! side_effects_p (SET_SRC (set))
293 && ! find_reg_note (insn, REG_RETVAL, 0)
294 /* An ADDRESSOF expression can turn into a use of the internal arg
295 pointer, so do not delete the initialization of the internal
296 arg pointer yet. If it is truly dead, flow will delete the
297 initializing insn. */
298 && SET_DEST (set) != current_function_internal_arg_pointer)
302 /* Now iterate optimizing jumps until nothing changes over one pass. */
304 old_max_reg = max_reg_num ();
309 for (insn = f; insn; insn = next)
312 rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
314 int this_is_simplejump, this_is_condjump, reversep = 0;
315 int this_is_condjump_in_parallel;
317 next = NEXT_INSN (insn);
319 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
320 jump. Try to optimize by duplicating the loop exit test if so.
321 This is only safe immediately after regscan, because it uses
322 the values of regno_first_uid and regno_last_uid. Don't do this
323 if optimizing for size. */
327 && GET_CODE (insn) == NOTE
328 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
329 && (temp1 = next_nonnote_insn (insn)) != 0
330 && simplejump_p (temp1))
332 temp = PREV_INSN (insn);
333 if (duplicate_loop_exit_test (insn))
336 next = NEXT_INSN (temp);
341 if (GET_CODE (insn) != JUMP_INSN)
344 this_is_simplejump = simplejump_p (insn);
345 this_is_condjump = condjump_p (insn);
346 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
348 /* Tension the labels in dispatch tables. */
350 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
351 changed |= tension_vector_labels (PATTERN (insn), 0);
352 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
353 changed |= tension_vector_labels (PATTERN (insn), 1);
355 /* See if this jump goes to another jump and redirect if so. */
356 nlabel = follow_jumps (JUMP_LABEL (insn));
357 if (nlabel != JUMP_LABEL (insn))
358 changed |= redirect_jump (insn, nlabel);
360 /* If a dispatch table always goes to the same place,
361 get rid of it and replace the insn that uses it. */
363 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
364 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
367 rtx pat = PATTERN (insn);
368 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
369 int len = XVECLEN (pat, diff_vec_p);
370 rtx dispatch = prev_real_insn (insn);
373 for (i = 0; i < len; i++)
374 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
375 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
380 && GET_CODE (dispatch) == JUMP_INSN
381 && JUMP_LABEL (dispatch) != 0
382 /* Don't mess with a casesi insn.
383 XXX according to the comment before computed_jump_p(),
384 all casesi insns should be a parallel of the jump
385 and a USE of a LABEL_REF. */
386 && ! ((set = single_set (dispatch)) != NULL
387 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
388 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
390 redirect_tablejump (dispatch,
391 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
396 /* If a jump references the end of the function, try to turn
397 it into a RETURN insn, possibly a conditional one. */
398 if (JUMP_LABEL (insn) != 0
399 && (next_active_insn (JUMP_LABEL (insn)) == 0
400 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
402 changed |= redirect_jump (insn, NULL_RTX);
404 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
406 /* Detect jump to following insn. */
407 if (reallabelprev == insn && this_is_condjump)
409 next = next_real_insn (JUMP_LABEL (insn));
415 /* Detect a conditional jump going to the same place
416 as an immediately following unconditional jump. */
417 else if (this_is_condjump
418 && (temp = next_active_insn (insn)) != 0
419 && simplejump_p (temp)
420 && (next_active_insn (JUMP_LABEL (insn))
421 == next_active_insn (JUMP_LABEL (temp))))
423 /* Don't mess up test coverage analysis. */
425 if (flag_test_coverage && !reload_completed)
426 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
427 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
438 /* Detect a conditional jump jumping over an unconditional jump. */
440 else if ((this_is_condjump || this_is_condjump_in_parallel)
441 && ! this_is_simplejump
442 && reallabelprev != 0
443 && GET_CODE (reallabelprev) == JUMP_INSN
444 && prev_active_insn (reallabelprev) == insn
445 && no_labels_between_p (insn, reallabelprev)
446 && simplejump_p (reallabelprev))
448 /* When we invert the unconditional jump, we will be
449 decrementing the usage count of its old label.
450 Make sure that we don't delete it now because that
451 might cause the following code to be deleted. */
452 rtx prev_uses = prev_nonnote_insn (reallabelprev);
453 rtx prev_label = JUMP_LABEL (insn);
456 ++LABEL_NUSES (prev_label);
458 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
460 /* It is very likely that if there are USE insns before
461 this jump, they hold REG_DEAD notes. These REG_DEAD
462 notes are no longer valid due to this optimization,
463 and will cause the life-analysis that following passes
464 (notably delayed-branch scheduling) to think that
465 these registers are dead when they are not.
467 To prevent this trouble, we just remove the USE insns
468 from the insn chain. */
470 while (prev_uses && GET_CODE (prev_uses) == INSN
471 && GET_CODE (PATTERN (prev_uses)) == USE)
473 rtx useless = prev_uses;
474 prev_uses = prev_nonnote_insn (prev_uses);
475 delete_insn (useless);
478 delete_insn (reallabelprev);
482 /* We can now safely delete the label if it is unreferenced
483 since the delete_insn above has deleted the BARRIER. */
484 if (prev_label && --LABEL_NUSES (prev_label) == 0)
485 delete_insn (prev_label);
487 next = NEXT_INSN (insn);
490 /* If we have an unconditional jump preceded by a USE, try to put
491 the USE before the target and jump there. This simplifies many
492 of the optimizations below since we don't have to worry about
493 dealing with these USE insns. We only do this if the label
494 being branch to already has the identical USE or if code
495 never falls through to that label. */
497 else if (this_is_simplejump
498 && (temp = prev_nonnote_insn (insn)) != 0
499 && GET_CODE (temp) == INSN
500 && GET_CODE (PATTERN (temp)) == USE
501 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
502 && (GET_CODE (temp1) == BARRIER
503 || (GET_CODE (temp1) == INSN
504 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
505 /* Don't do this optimization if we have a loop containing
506 only the USE instruction, and the loop start label has
507 a usage count of 1. This is because we will redo this
508 optimization everytime through the outer loop, and jump
509 opt will never exit. */
510 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
511 && temp2 == JUMP_LABEL (insn)
512 && LABEL_NUSES (temp2) == 1))
514 if (GET_CODE (temp1) == BARRIER)
516 emit_insn_after (PATTERN (temp), temp1);
517 temp1 = NEXT_INSN (temp1);
521 redirect_jump (insn, get_label_before (temp1));
522 reallabelprev = prev_real_insn (temp1);
524 next = NEXT_INSN (insn);
527 /* Simplify if (...) x = a; else x = b; by converting it
528 to x = b; if (...) x = a;
529 if B is sufficiently simple, the test doesn't involve X,
530 and nothing in the test modifies B or X.
532 If we have small register classes, we also can't do this if X
535 If the "x = b;" insn has any REG_NOTES, we don't do this because
536 of the possibility that we are running after CSE and there is a
537 REG_EQUAL note that is only valid if the branch has already been
538 taken. If we move the insn with the REG_EQUAL note, we may
539 fold the comparison to always be false in a later CSE pass.
540 (We could also delete the REG_NOTES when moving the insn, but it
541 seems simpler to not move it.) An exception is that we can move
542 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
543 value is the same as "b".
545 INSN is the branch over the `else' part.
549 TEMP to the jump insn preceding "x = a;"
551 TEMP2 to the insn that sets "x = b;"
552 TEMP3 to the insn that sets "x = a;"
553 TEMP4 to the set of "x = b"; */
555 if (this_is_simplejump
556 && (temp3 = prev_active_insn (insn)) != 0
557 && GET_CODE (temp3) == INSN
558 && (temp4 = single_set (temp3)) != 0
559 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
560 && (! SMALL_REGISTER_CLASSES
561 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
562 && (temp2 = next_active_insn (insn)) != 0
563 && GET_CODE (temp2) == INSN
564 && (temp4 = single_set (temp2)) != 0
565 && rtx_equal_p (SET_DEST (temp4), temp1)
566 && ! side_effects_p (SET_SRC (temp4))
567 && ! may_trap_p (SET_SRC (temp4))
568 && (REG_NOTES (temp2) == 0
569 || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
570 || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
571 && XEXP (REG_NOTES (temp2), 1) == 0
572 && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
574 && (temp = prev_active_insn (temp3)) != 0
575 && condjump_p (temp) && ! simplejump_p (temp)
576 /* TEMP must skip over the "x = a;" insn */
577 && prev_real_insn (JUMP_LABEL (temp)) == insn
578 && no_labels_between_p (insn, JUMP_LABEL (temp))
579 /* There must be no other entries to the "x = b;" insn. */
580 && no_labels_between_p (JUMP_LABEL (temp), temp2)
581 /* INSN must either branch to the insn after TEMP2 or the insn
582 after TEMP2 must branch to the same place as INSN. */
583 && (reallabelprev == temp2
584 || ((temp5 = next_active_insn (temp2)) != 0
585 && simplejump_p (temp5)
586 && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
588 /* The test expression, X, may be a complicated test with
589 multiple branches. See if we can find all the uses of
590 the label that TEMP branches to without hitting a CALL_INSN
591 or a jump to somewhere else. */
592 rtx target = JUMP_LABEL (temp);
593 int nuses = LABEL_NUSES (target);
599 /* Set P to the first jump insn that goes around "x = a;". */
600 for (p = temp; nuses && p; p = prev_nonnote_insn (p))
602 if (GET_CODE (p) == JUMP_INSN)
604 if (condjump_p (p) && ! simplejump_p (p)
605 && JUMP_LABEL (p) == target)
614 else if (GET_CODE (p) == CALL_INSN)
619 /* We cannot insert anything between a set of cc and its use
620 so if P uses cc0, we must back up to the previous insn. */
621 q = prev_nonnote_insn (p);
622 if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
623 && sets_cc0_p (PATTERN (q)))
630 /* If we found all the uses and there was no data conflict, we
631 can move the assignment unless we can branch into the middle
634 && no_labels_between_p (p, insn)
635 && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
636 && ! reg_set_between_p (temp1, p, temp3)
637 && (GET_CODE (SET_SRC (temp4)) == CONST_INT
638 || ! modified_between_p (SET_SRC (temp4), p, temp2))
639 /* Verify that registers used by the jump are not clobbered
640 by the instruction being moved. */
641 && ! regs_set_between_p (PATTERN (temp),
645 emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
648 /* Set NEXT to an insn that we know won't go away. */
649 next = next_active_insn (insn);
651 /* Delete the jump around the set. Note that we must do
652 this before we redirect the test jumps so that it won't
653 delete the code immediately following the assignment
654 we moved (which might be a jump). */
658 /* We either have two consecutive labels or a jump to
659 a jump, so adjust all the JUMP_INSNs to branch to where
661 for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
662 if (GET_CODE (p) == JUMP_INSN)
663 redirect_jump (p, target);
666 next = NEXT_INSN (insn);
671 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
672 to x = a; if (...) goto l; x = b;
673 if A is sufficiently simple, the test doesn't involve X,
674 and nothing in the test modifies A or X.
676 If we have small register classes, we also can't do this if X
679 If the "x = a;" insn has any REG_NOTES, we don't do this because
680 of the possibility that we are running after CSE and there is a
681 REG_EQUAL note that is only valid if the branch has already been
682 taken. If we move the insn with the REG_EQUAL note, we may
683 fold the comparison to always be false in a later CSE pass.
684 (We could also delete the REG_NOTES when moving the insn, but it
685 seems simpler to not move it.) An exception is that we can move
686 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
687 value is the same as "a".
693 TEMP to the jump insn preceding "x = a;"
695 TEMP2 to the insn that sets "x = b;"
696 TEMP3 to the insn that sets "x = a;"
697 TEMP4 to the set of "x = a"; */
699 if (this_is_simplejump
700 && (temp2 = next_active_insn (insn)) != 0
701 && GET_CODE (temp2) == INSN
702 && (temp4 = single_set (temp2)) != 0
703 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
704 && (! SMALL_REGISTER_CLASSES
705 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
706 && (temp3 = prev_active_insn (insn)) != 0
707 && GET_CODE (temp3) == INSN
708 && (temp4 = single_set (temp3)) != 0
709 && rtx_equal_p (SET_DEST (temp4), temp1)
710 && ! side_effects_p (SET_SRC (temp4))
711 && ! may_trap_p (SET_SRC (temp4))
712 && (REG_NOTES (temp3) == 0
713 || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
714 || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
715 && XEXP (REG_NOTES (temp3), 1) == 0
716 && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
718 && (temp = prev_active_insn (temp3)) != 0
719 && condjump_p (temp) && ! simplejump_p (temp)
720 /* TEMP must skip over the "x = a;" insn */
721 && prev_real_insn (JUMP_LABEL (temp)) == insn
722 && no_labels_between_p (temp, insn))
724 rtx prev_label = JUMP_LABEL (temp);
725 rtx insert_after = prev_nonnote_insn (temp);
728 /* We cannot insert anything between a set of cc and its use. */
729 if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
730 && sets_cc0_p (PATTERN (insert_after)))
731 insert_after = prev_nonnote_insn (insert_after);
733 ++LABEL_NUSES (prev_label);
736 && no_labels_between_p (insert_after, temp)
737 && ! reg_referenced_between_p (temp1, insert_after, temp3)
738 && ! reg_referenced_between_p (temp1, temp3,
740 && ! reg_set_between_p (temp1, insert_after, temp)
741 && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
742 /* Verify that registers used by the jump are not clobbered
743 by the instruction being moved. */
744 && ! regs_set_between_p (PATTERN (temp),
747 && invert_jump (temp, JUMP_LABEL (insn)))
749 emit_insn_after_with_line_notes (PATTERN (temp3),
750 insert_after, temp3);
753 /* Set NEXT to an insn that we know won't go away. */
757 if (prev_label && --LABEL_NUSES (prev_label) == 0)
758 delete_insn (prev_label);
763 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
765 /* If we have if (...) x = exp; and branches are expensive,
766 EXP is a single insn, does not have any side effects, cannot
767 trap, and is not too costly, convert this to
768 t = exp; if (...) x = t;
770 Don't do this when we have CC0 because it is unlikely to help
771 and we'd need to worry about where to place the new insn and
772 the potential for conflicts. We also can't do this when we have
773 notes on the insn for the same reason as above.
775 If we have conditional arithmetic, this will make this
776 harder to optimize later and isn't needed, so don't do it
781 TEMP to the "x = exp;" insn.
782 TEMP1 to the single set in the "x = exp;" insn.
785 if (! reload_completed
786 && this_is_condjump && ! this_is_simplejump
788 && (temp = next_nonnote_insn (insn)) != 0
789 && GET_CODE (temp) == INSN
790 && REG_NOTES (temp) == 0
791 && (reallabelprev == temp
792 || ((temp2 = next_active_insn (temp)) != 0
793 && simplejump_p (temp2)
794 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
795 && (temp1 = single_set (temp)) != 0
796 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
797 && (! SMALL_REGISTER_CLASSES
798 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
799 && GET_CODE (SET_SRC (temp1)) != REG
800 && GET_CODE (SET_SRC (temp1)) != SUBREG
801 && GET_CODE (SET_SRC (temp1)) != CONST_INT
802 && ! side_effects_p (SET_SRC (temp1))
803 && ! may_trap_p (SET_SRC (temp1))
804 && rtx_cost (SET_SRC (temp1), SET) < 10)
806 rtx new = gen_reg_rtx (GET_MODE (temp2));
808 if ((temp3 = find_insert_position (insn, temp))
809 && validate_change (temp, &SET_DEST (temp1), new, 0))
811 next = emit_insn_after (gen_move_insn (temp2, new), insn);
812 emit_insn_after_with_line_notes (PATTERN (temp),
813 PREV_INSN (temp3), temp);
815 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
819 reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
820 old_max_reg = max_reg_num ();
825 /* Similarly, if it takes two insns to compute EXP but they
826 have the same destination. Here TEMP3 will be the second
827 insn and TEMP4 the SET from that insn. */
829 if (! reload_completed
830 && this_is_condjump && ! this_is_simplejump
832 && (temp = next_nonnote_insn (insn)) != 0
833 && GET_CODE (temp) == INSN
834 && REG_NOTES (temp) == 0
835 && (temp3 = next_nonnote_insn (temp)) != 0
836 && GET_CODE (temp3) == INSN
837 && REG_NOTES (temp3) == 0
838 && (reallabelprev == temp3
839 || ((temp2 = next_active_insn (temp3)) != 0
840 && simplejump_p (temp2)
841 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
842 && (temp1 = single_set (temp)) != 0
843 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
844 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
845 && (! SMALL_REGISTER_CLASSES
846 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
847 && ! side_effects_p (SET_SRC (temp1))
848 && ! may_trap_p (SET_SRC (temp1))
849 && rtx_cost (SET_SRC (temp1), SET) < 10
850 && (temp4 = single_set (temp3)) != 0
851 && rtx_equal_p (SET_DEST (temp4), temp2)
852 && ! side_effects_p (SET_SRC (temp4))
853 && ! may_trap_p (SET_SRC (temp4))
854 && rtx_cost (SET_SRC (temp4), SET) < 10)
856 rtx new = gen_reg_rtx (GET_MODE (temp2));
858 if ((temp5 = find_insert_position (insn, temp))
859 && (temp6 = find_insert_position (insn, temp3))
860 && validate_change (temp, &SET_DEST (temp1), new, 0))
862 /* Use the earliest of temp5 and temp6. */
865 next = emit_insn_after (gen_move_insn (temp2, new), insn);
866 emit_insn_after_with_line_notes (PATTERN (temp),
867 PREV_INSN (temp6), temp);
868 emit_insn_after_with_line_notes
869 (replace_rtx (PATTERN (temp3), temp2, new),
870 PREV_INSN (temp6), temp3);
873 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
877 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
878 old_max_reg = max_reg_num ();
883 /* Finally, handle the case where two insns are used to
884 compute EXP but a temporary register is used. Here we must
885 ensure that the temporary register is not used anywhere else. */
887 if (! reload_completed
889 && this_is_condjump && ! this_is_simplejump
891 && (temp = next_nonnote_insn (insn)) != 0
892 && GET_CODE (temp) == INSN
893 && REG_NOTES (temp) == 0
894 && (temp3 = next_nonnote_insn (temp)) != 0
895 && GET_CODE (temp3) == INSN
896 && REG_NOTES (temp3) == 0
897 && (reallabelprev == temp3
898 || ((temp2 = next_active_insn (temp3)) != 0
899 && simplejump_p (temp2)
900 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
901 && (temp1 = single_set (temp)) != 0
902 && (temp5 = SET_DEST (temp1),
903 (GET_CODE (temp5) == REG
904 || (GET_CODE (temp5) == SUBREG
905 && (temp5 = SUBREG_REG (temp5),
906 GET_CODE (temp5) == REG))))
907 && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
908 && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
909 && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
910 && ! side_effects_p (SET_SRC (temp1))
911 && ! may_trap_p (SET_SRC (temp1))
912 && rtx_cost (SET_SRC (temp1), SET) < 10
913 && (temp4 = single_set (temp3)) != 0
914 && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
915 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
916 && (! SMALL_REGISTER_CLASSES
917 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
918 && rtx_equal_p (SET_DEST (temp4), temp2)
919 && ! side_effects_p (SET_SRC (temp4))
920 && ! may_trap_p (SET_SRC (temp4))
921 && rtx_cost (SET_SRC (temp4), SET) < 10)
923 rtx new = gen_reg_rtx (GET_MODE (temp2));
925 if ((temp5 = find_insert_position (insn, temp))
926 && (temp6 = find_insert_position (insn, temp3))
927 && validate_change (temp3, &SET_DEST (temp4), new, 0))
929 /* Use the earliest of temp5 and temp6. */
932 next = emit_insn_after (gen_move_insn (temp2, new), insn);
933 emit_insn_after_with_line_notes (PATTERN (temp),
934 PREV_INSN (temp6), temp);
935 emit_insn_after_with_line_notes (PATTERN (temp3),
936 PREV_INSN (temp6), temp3);
939 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
943 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
944 old_max_reg = max_reg_num ();
948 #endif /* HAVE_cc0 */
950 #ifdef HAVE_conditional_arithmetic
951 /* ??? This is disabled in genconfig, as this simple-minded
952 transformation can incredibly lengthen register lifetimes.
954 Consider this example from cexp.c's yyparse:
957 (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
958 (label_ref 248) (pc)))
959 237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
960 239 (set (pc) (label_ref 2382))
961 248 (code_label ("yybackup"))
963 This will be transformed to:
965 237 (set (reg/i:DI 0 $0)
966 (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
967 (const_int 1 [0x1]) (reg/i:DI 0 $0)))
969 (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
970 (label_ref 2382) (pc)))
972 which, from this narrow viewpoint looks fine. Except that
973 between this and 3 other ocurrences of the same pattern, $0
974 is now live for basically the entire function, and we'll
975 get an abort in caller_save.
977 Any replacement for this code should recall that a set of
978 a register that is not live need not, and indeed should not,
979 be conditionalized. Either that, or delay the transformation
980 until after register allocation. */
982 /* See if this is a conditional jump around a small number of
983 instructions that we can conditionalize. Don't do this before
984 the initial CSE pass or after reload.
986 We reject any insns that have side effects or may trap.
987 Strictly speaking, this is not needed since the machine may
988 support conditionalizing these too, but we won't deal with that
989 now. Specifically, this means that we can't conditionalize a
990 CALL_INSN, which some machines, such as the ARC, can do, but
991 this is a very minor optimization. */
992 if (this_is_condjump && ! this_is_simplejump
993 && cse_not_expected && optimize > 0 && ! reload_completed
995 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn)), 0),
998 rtx ourcond = XEXP (SET_SRC (PATTERN (insn)), 0);
1000 char *storage = (char *) oballoc (0);
1001 int last_insn = 0, failed = 0;
1002 rtx changed_jump = 0;
1004 ourcond = gen_rtx (reverse_condition (GET_CODE (ourcond)),
1005 VOIDmode, XEXP (ourcond, 0),
1008 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
1009 of this insn. We see if we think we can conditionalize the
1010 insns we pass. For now, we only deal with insns that have
1011 one SET. We stop after an insn that modifies anything in
1012 OURCOND, if we have too many insns, or if we have an insn
1013 with a side effect or that may trip. Note that we will
1014 be modifying any unconditional jumps we encounter to be
1015 conditional; this will have the effect of also doing this
1016 optimization on the "else" the next time around. */
1017 for (temp1 = NEXT_INSN (insn);
1018 num_insns <= BRANCH_COST && ! failed && temp1 != 0
1019 && GET_CODE (temp1) != CODE_LABEL;
1020 temp1 = NEXT_INSN (temp1))
1022 /* Ignore everything but an active insn. */
1023 if (GET_RTX_CLASS (GET_CODE (temp1)) != 'i'
1024 || GET_CODE (PATTERN (temp1)) == USE
1025 || GET_CODE (PATTERN (temp1)) == CLOBBER)
1028 /* If this was an unconditional jump, record it since we'll
1029 need to remove the BARRIER if we succeed. We can only
1030 have one such jump since there must be a label after
1031 the BARRIER and it's either ours, in which case it's the
1032 only one or some other, in which case we'd fail.
1033 Likewise if it's a CALL_INSN followed by a BARRIER. */
1035 if (simplejump_p (temp1)
1036 || (GET_CODE (temp1) == CALL_INSN
1037 && NEXT_INSN (temp1) != 0
1038 && GET_CODE (NEXT_INSN (temp1)) == BARRIER))
1040 if (changed_jump == 0)
1041 changed_jump = temp1;
1044 = gen_rtx_INSN_LIST (VOIDmode, temp1, changed_jump);
1047 /* See if we are allowed another insn and if this insn
1048 if one we think we may be able to handle. */
1049 if (++num_insns > BRANCH_COST
1051 || (((temp2 = single_set (temp1)) == 0
1052 || side_effects_p (SET_SRC (temp2))
1053 || may_trap_p (SET_SRC (temp2)))
1054 && GET_CODE (temp1) != CALL_INSN))
1056 else if (temp2 != 0)
1057 validate_change (temp1, &SET_SRC (temp2),
1058 gen_rtx_IF_THEN_ELSE
1059 (GET_MODE (SET_DEST (temp2)),
1061 SET_SRC (temp2), SET_DEST (temp2)),
1065 /* This is a CALL_INSN that doesn't have a SET. */
1066 rtx *call_loc = &PATTERN (temp1);
1068 if (GET_CODE (*call_loc) == PARALLEL)
1069 call_loc = &XVECEXP (*call_loc, 0, 0);
1071 validate_change (temp1, call_loc,
1072 gen_rtx_IF_THEN_ELSE
1073 (VOIDmode, copy_rtx (ourcond),
1074 *call_loc, const0_rtx),
1079 if (modified_in_p (ourcond, temp1))
1083 /* If we've reached our jump label, haven't failed, and all
1084 the changes above are valid, we can delete this jump
1085 insn. Also remove a BARRIER after any jump that used
1086 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1087 that might have previously been present on insns we
1088 made conditional. */
1089 if (temp1 == JUMP_LABEL (insn) && ! failed
1090 && apply_change_group ())
1092 for (temp1 = NEXT_INSN (insn); temp1 != JUMP_LABEL (insn);
1093 temp1 = NEXT_INSN (temp1))
1094 if (GET_RTX_CLASS (GET_CODE (temp1)) == 'i')
1095 for (temp2 = REG_NOTES (temp1); temp2 != 0;
1096 temp2 = XEXP (temp2, 1))
1097 if (REG_NOTE_KIND (temp2) == REG_EQUAL
1098 || REG_NOTE_KIND (temp2) == REG_EQUIV)
1099 remove_note (temp1, temp2);
1101 if (changed_jump != 0)
1103 while (GET_CODE (changed_jump) == INSN_LIST)
1105 delete_barrier (NEXT_INSN (XEXP (changed_jump, 0)));
1106 changed_jump = XEXP (changed_jump, 1);
1109 delete_barrier (NEXT_INSN (changed_jump));
1123 /* If branches are expensive, convert
1124 if (foo) bar++; to bar += (foo != 0);
1125 and similarly for "bar--;"
1127 INSN is the conditional branch around the arithmetic. We set:
1129 TEMP is the arithmetic insn.
1130 TEMP1 is the SET doing the arithmetic.
1131 TEMP2 is the operand being incremented or decremented.
1132 TEMP3 to the condition being tested.
1133 TEMP4 to the earliest insn used to find the condition. */
1135 if ((BRANCH_COST >= 2
1143 && ! reload_completed
1144 && this_is_condjump && ! this_is_simplejump
1145 && (temp = next_nonnote_insn (insn)) != 0
1146 && (temp1 = single_set (temp)) != 0
1147 && (temp2 = SET_DEST (temp1),
1148 GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
1149 && GET_CODE (SET_SRC (temp1)) == PLUS
1150 && (XEXP (SET_SRC (temp1), 1) == const1_rtx
1151 || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
1152 && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
1153 && ! side_effects_p (temp2)
1154 && ! may_trap_p (temp2)
1155 /* INSN must either branch to the insn after TEMP or the insn
1156 after TEMP must branch to the same place as INSN. */
1157 && (reallabelprev == temp
1158 || ((temp3 = next_active_insn (temp)) != 0
1159 && simplejump_p (temp3)
1160 && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
1161 && (temp3 = get_condition (insn, &temp4)) != 0
1162 /* We must be comparing objects whose modes imply the size.
1163 We could handle BLKmode if (1) emit_store_flag could
1164 and (2) we could find the size reliably. */
1165 && GET_MODE (XEXP (temp3, 0)) != BLKmode
1166 && can_reverse_comparison_p (temp3, insn))
1168 rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
1169 enum rtx_code code = reverse_condition (GET_CODE (temp3));
1173 /* It must be the case that TEMP2 is not modified in the range
1174 [TEMP4, INSN). The one exception we make is if the insn
1175 before INSN sets TEMP2 to something which is also unchanged
1176 in that range. In that case, we can move the initialization
1177 into our sequence. */
1179 if ((temp5 = prev_active_insn (insn)) != 0
1180 && no_labels_between_p (temp5, insn)
1181 && GET_CODE (temp5) == INSN
1182 && (temp6 = single_set (temp5)) != 0
1183 && rtx_equal_p (temp2, SET_DEST (temp6))
1184 && (CONSTANT_P (SET_SRC (temp6))
1185 || GET_CODE (SET_SRC (temp6)) == REG
1186 || GET_CODE (SET_SRC (temp6)) == SUBREG))
1188 emit_insn (PATTERN (temp5));
1190 init = SET_SRC (temp6);
1193 if (CONSTANT_P (init)
1194 || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
1195 target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
1196 XEXP (temp3, 0), XEXP (temp3, 1),
1198 (code == LTU || code == LEU
1199 || code == GTU || code == GEU), 1);
1201 /* If we can do the store-flag, do the addition or
1205 target = expand_binop (GET_MODE (temp2),
1206 (XEXP (SET_SRC (temp1), 1) == const1_rtx
1207 ? add_optab : sub_optab),
1208 temp2, target, temp2, 0, OPTAB_WIDEN);
1212 /* Put the result back in temp2 in case it isn't already.
1213 Then replace the jump, possible a CC0-setting insn in
1214 front of the jump, and TEMP, with the sequence we have
1217 if (target != temp2)
1218 emit_move_insn (temp2, target);
1223 emit_insns_before (seq, temp4);
1227 delete_insn (init_insn);
1229 next = NEXT_INSN (insn);
1231 delete_insn (prev_nonnote_insn (insn));
1237 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1238 old_max_reg = max_reg_num ();
1248 /* Try to use a conditional move (if the target has them), or a
1249 store-flag insn. If the target has conditional arithmetic as
1250 well as conditional move, the above code will have done something.
1251 Note that we prefer the above code since it is more general: the
1252 code below can make changes that require work to undo.
1254 The general case here is:
1256 1) x = a; if (...) x = b; and
1259 If the jump would be faster, the machine should not have defined
1260 the movcc or scc insns!. These cases are often made by the
1261 previous optimization.
1263 The second case is treated as x = x; if (...) x = b;.
1265 INSN here is the jump around the store. We set:
1267 TEMP to the "x op= b;" insn.
1270 TEMP3 to A (X in the second case).
1271 TEMP4 to the condition being tested.
1272 TEMP5 to the earliest insn used to find the condition.
1273 TEMP6 to the SET of TEMP. */
1275 if (/* We can't do this after reload has completed. */
1277 #ifdef HAVE_conditional_arithmetic
1278 /* Defer this until after CSE so the above code gets the
1279 first crack at it. */
1282 && this_is_condjump && ! this_is_simplejump
1283 /* Set TEMP to the "x = b;" insn. */
1284 && (temp = next_nonnote_insn (insn)) != 0
1285 && GET_CODE (temp) == INSN
1286 && (temp6 = single_set (temp)) != NULL_RTX
1287 && GET_CODE (temp1 = SET_DEST (temp6)) == REG
1288 && (! SMALL_REGISTER_CLASSES
1289 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
1290 && ! side_effects_p (temp2 = SET_SRC (temp6))
1291 && ! may_trap_p (temp2)
1292 /* Allow either form, but prefer the former if both apply.
1293 There is no point in using the old value of TEMP1 if
1294 it is a register, since cse will alias them. It can
1295 lose if the old value were a hard register since CSE
1296 won't replace hard registers. Avoid using TEMP3 if
1297 small register classes and it is a hard register. */
1298 && (((temp3 = reg_set_last (temp1, insn)) != 0
1299 && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
1300 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
1301 /* Make the latter case look like x = x; if (...) x = b; */
1302 || (temp3 = temp1, 1))
1303 /* INSN must either branch to the insn after TEMP or the insn
1304 after TEMP must branch to the same place as INSN. */
1305 && (reallabelprev == temp
1306 || ((temp4 = next_active_insn (temp)) != 0
1307 && simplejump_p (temp4)
1308 && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
1309 && (temp4 = get_condition (insn, &temp5)) != 0
1310 /* We must be comparing objects whose modes imply the size.
1311 We could handle BLKmode if (1) emit_store_flag could
1312 and (2) we could find the size reliably. */
1313 && GET_MODE (XEXP (temp4, 0)) != BLKmode
1314 /* Even if branches are cheap, the store_flag optimization
1315 can win when the operation to be performed can be
1316 expressed directly. */
1318 /* If the previous insn sets CC0 and something else, we can't
1319 do this since we are going to delete that insn. */
1321 && ! ((temp6 = prev_nonnote_insn (insn)) != 0
1322 && GET_CODE (temp6) == INSN
1323 && (sets_cc0_p (PATTERN (temp6)) == -1
1324 || (sets_cc0_p (PATTERN (temp6)) == 1
1325 && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
1329 #ifdef HAVE_conditional_move
1330 /* First try a conditional move. */
1332 enum rtx_code code = GET_CODE (temp4);
1334 rtx cond0, cond1, aval, bval;
1335 rtx target, new_insn;
1337 /* Copy the compared variables into cond0 and cond1, so that
1338 any side effects performed in or after the old comparison,
1339 will not affect our compare which will come later. */
1340 /* ??? Is it possible to just use the comparison in the jump
1341 insn? After all, we're going to delete it. We'd have
1342 to modify emit_conditional_move to take a comparison rtx
1343 instead or write a new function. */
1344 cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
1345 /* We want the target to be able to simplify comparisons with
1346 zero (and maybe other constants as well), so don't create
1347 pseudos for them. There's no need to either. */
1348 if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
1349 || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
1350 cond1 = XEXP (temp4, 1);
1352 cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
1354 /* Careful about copying these values -- an IOR or what may
1355 need to do other things, like clobber flags. */
1356 /* ??? Assume for the moment that AVAL is ok. */
1361 /* We're dealing with a single_set insn with no side effects
1362 on SET_SRC. We do need to be reasonably certain that if
1363 we need to force BVAL into a register that we won't
1364 clobber the flags -- general_operand should suffice. */
1365 if (general_operand (temp2, GET_MODE (var)))
1369 bval = gen_reg_rtx (GET_MODE (var));
1370 new_insn = copy_rtx (temp);
1371 temp6 = single_set (new_insn);
1372 SET_DEST (temp6) = bval;
1373 emit_insn (PATTERN (new_insn));
1376 target = emit_conditional_move (var, code,
1377 cond0, cond1, VOIDmode,
1378 aval, bval, GET_MODE (var),
1379 (code == LTU || code == GEU
1380 || code == LEU || code == GTU));
1384 rtx seq1, seq2, last;
1387 /* Save the conditional move sequence but don't emit it
1388 yet. On some machines, like the alpha, it is possible
1389 that temp5 == insn, so next generate the sequence that
1390 saves the compared values and then emit both
1391 sequences ensuring seq1 occurs before seq2. */
1392 seq2 = get_insns ();
1395 /* "Now that we can't fail..." Famous last words.
1396 Generate the copy insns that preserve the compared
1399 emit_move_insn (cond0, XEXP (temp4, 0));
1400 if (cond1 != XEXP (temp4, 1))
1401 emit_move_insn (cond1, XEXP (temp4, 1));
1402 seq1 = get_insns ();
1405 /* Validate the sequence -- this may be some weird
1406 bit-extract-and-test instruction for which there
1407 exists no complimentary bit-extract insn. */
1409 for (last = seq1; last ; last = NEXT_INSN (last))
1410 if (recog_memoized (last) < 0)
1418 emit_insns_before (seq1, temp5);
1420 /* Insert conditional move after insn, to be sure
1421 that the jump and a possible compare won't be
1423 last = emit_insns_after (seq2, insn);
1425 /* ??? We can also delete the insn that sets X to A.
1426 Flow will do it too though. */
1428 next = NEXT_INSN (insn);
1433 reg_scan_update (seq1, NEXT_INSN (last),
1435 old_max_reg = max_reg_num ();
1447 /* That didn't work, try a store-flag insn.
1449 We further divide the cases into:
1451 1) x = a; if (...) x = b; and either A or B is zero,
1452 2) if (...) x = 0; and jumps are expensive,
1453 3) x = a; if (...) x = b; and A and B are constants where all
1454 the set bits in A are also set in B and jumps are expensive,
1455 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1457 5) if (...) x = b; if jumps are even more expensive. */
1459 if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
1460 /* We will be passing this as operand into expand_and. No
1461 good if it's not valid as an operand. */
1462 && general_operand (temp2, GET_MODE (temp2))
1463 && ((GET_CODE (temp3) == CONST_INT)
1464 /* Make the latter case look like
1465 x = x; if (...) x = 0; */
1468 && temp2 == const0_rtx)
1469 || BRANCH_COST >= 3)))
1470 /* If B is zero, OK; if A is zero, can only do (1) if we
1471 can reverse the condition. See if (3) applies possibly
1472 by reversing the condition. Prefer reversing to (4) when
1473 branches are very expensive. */
1474 && (((BRANCH_COST >= 2
1475 || STORE_FLAG_VALUE == -1
1476 || (STORE_FLAG_VALUE == 1
1477 /* Check that the mask is a power of two,
1478 so that it can probably be generated
1480 && GET_CODE (temp3) == CONST_INT
1481 && exact_log2 (INTVAL (temp3)) >= 0))
1482 && (reversep = 0, temp2 == const0_rtx))
1483 || ((BRANCH_COST >= 2
1484 || STORE_FLAG_VALUE == -1
1485 || (STORE_FLAG_VALUE == 1
1486 && GET_CODE (temp2) == CONST_INT
1487 && exact_log2 (INTVAL (temp2)) >= 0))
1488 && temp3 == const0_rtx
1489 && (reversep = can_reverse_comparison_p (temp4, insn)))
1490 || (BRANCH_COST >= 2
1491 && GET_CODE (temp2) == CONST_INT
1492 && GET_CODE (temp3) == CONST_INT
1493 && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
1494 || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
1495 && (reversep = can_reverse_comparison_p (temp4,
1497 || BRANCH_COST >= 3)
1500 enum rtx_code code = GET_CODE (temp4);
1501 rtx uval, cval, var = temp1;
1505 /* If necessary, reverse the condition. */
1507 code = reverse_condition (code), uval = temp2, cval = temp3;
1509 uval = temp3, cval = temp2;
1511 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1512 is the constant 1, it is best to just compute the result
1513 directly. If UVAL is constant and STORE_FLAG_VALUE
1514 includes all of its bits, it is best to compute the flag
1515 value unnormalized and `and' it with UVAL. Otherwise,
1516 normalize to -1 and `and' with UVAL. */
1517 normalizep = (cval != const0_rtx ? -1
1518 : (uval == const1_rtx ? 1
1519 : (GET_CODE (uval) == CONST_INT
1520 && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
1523 /* We will be putting the store-flag insn immediately in
1524 front of the comparison that was originally being done,
1525 so we know all the variables in TEMP4 will be valid.
1526 However, this might be in front of the assignment of
1527 A to VAR. If it is, it would clobber the store-flag
1528 we will be emitting.
1530 Therefore, emit into a temporary which will be copied to
1531 VAR immediately after TEMP. */
1534 target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
1535 XEXP (temp4, 0), XEXP (temp4, 1),
1537 (code == LTU || code == LEU
1538 || code == GEU || code == GTU),
1548 /* Put the store-flag insns in front of the first insn
1549 used to compute the condition to ensure that we
1550 use the same values of them as the current
1551 comparison. However, the remainder of the insns we
1552 generate will be placed directly in front of the
1553 jump insn, in case any of the pseudos we use
1554 are modified earlier. */
1556 emit_insns_before (seq, temp5);
1560 /* Both CVAL and UVAL are non-zero. */
1561 if (cval != const0_rtx && uval != const0_rtx)
1565 tem1 = expand_and (uval, target, NULL_RTX);
1566 if (GET_CODE (cval) == CONST_INT
1567 && GET_CODE (uval) == CONST_INT
1568 && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
1572 tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
1573 target, NULL_RTX, 0);
1574 tem2 = expand_and (cval, tem2,
1575 (GET_CODE (tem2) == REG
1579 /* If we usually make new pseudos, do so here. This
1580 turns out to help machines that have conditional
1582 /* ??? Conditional moves have already been handled.
1583 This may be obsolete. */
1585 if (flag_expensive_optimizations)
1588 target = expand_binop (GET_MODE (var), ior_optab,
1592 else if (normalizep != 1)
1594 /* We know that either CVAL or UVAL is zero. If
1595 UVAL is zero, negate TARGET and `and' with CVAL.
1596 Otherwise, `and' with UVAL. */
1597 if (uval == const0_rtx)
1599 target = expand_unop (GET_MODE (var), one_cmpl_optab,
1600 target, NULL_RTX, 0);
1604 target = expand_and (uval, target,
1605 (GET_CODE (target) == REG
1606 && ! preserve_subexpressions_p ()
1607 ? target : NULL_RTX));
1610 emit_move_insn (var, target);
1614 /* If INSN uses CC0, we must not separate it from the
1615 insn that sets cc0. */
1616 if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
1617 before = prev_nonnote_insn (before);
1619 emit_insns_before (seq, before);
1622 next = NEXT_INSN (insn);
1627 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1628 old_max_reg = max_reg_num ();
1640 /* Simplify if (...) x = 1; else {...} if (x) ...
1641 We recognize this case scanning backwards as well.
1643 TEMP is the assignment to x;
1644 TEMP1 is the label at the head of the second if. */
1645 /* ?? This should call get_condition to find the values being
1646 compared, instead of looking for a COMPARE insn when HAVE_cc0
1647 is not defined. This would allow it to work on the m88k. */
1648 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1649 is not defined and the condition is tested by a separate compare
1650 insn. This is because the code below assumes that the result
1651 of the compare dies in the following branch.
1653 Not only that, but there might be other insns between the
1654 compare and branch whose results are live. Those insns need
1657 A way to fix this is to move the insns at JUMP_LABEL (insn)
1658 to before INSN. If we are running before flow, they will
1659 be deleted if they aren't needed. But this doesn't work
1662 This is really a special-case of jump threading, anyway. The
1663 right thing to do is to replace this and jump threading with
1664 much simpler code in cse.
1666 This code has been turned off in the non-cc0 case in the
1670 else if (this_is_simplejump
1671 /* Safe to skip USE and CLOBBER insns here
1672 since they will not be deleted. */
1673 && (temp = prev_active_insn (insn))
1674 && no_labels_between_p (temp, insn)
1675 && GET_CODE (temp) == INSN
1676 && GET_CODE (PATTERN (temp)) == SET
1677 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1678 && CONSTANT_P (SET_SRC (PATTERN (temp)))
1679 && (temp1 = next_active_insn (JUMP_LABEL (insn)))
1680 /* If we find that the next value tested is `x'
1681 (TEMP1 is the insn where this happens), win. */
1682 && GET_CODE (temp1) == INSN
1683 && GET_CODE (PATTERN (temp1)) == SET
1685 /* Does temp1 `tst' the value of x? */
1686 && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
1687 && SET_DEST (PATTERN (temp1)) == cc0_rtx
1688 && (temp1 = next_nonnote_insn (temp1))
1690 /* Does temp1 compare the value of x against zero? */
1691 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1692 && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
1693 && (XEXP (SET_SRC (PATTERN (temp1)), 0)
1694 == SET_DEST (PATTERN (temp)))
1695 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1696 && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1698 && condjump_p (temp1))
1700 /* Get the if_then_else from the condjump. */
1701 rtx choice = SET_SRC (PATTERN (temp1));
1702 if (GET_CODE (choice) == IF_THEN_ELSE)
1704 enum rtx_code code = GET_CODE (XEXP (choice, 0));
1705 rtx val = SET_SRC (PATTERN (temp));
1707 = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
1711 if (cond == const_true_rtx)
1712 ultimate = XEXP (choice, 1);
1713 else if (cond == const0_rtx)
1714 ultimate = XEXP (choice, 2);
1718 if (ultimate == pc_rtx)
1719 ultimate = get_label_after (temp1);
1720 else if (ultimate && GET_CODE (ultimate) != RETURN)
1721 ultimate = XEXP (ultimate, 0);
1723 if (ultimate && JUMP_LABEL(insn) != ultimate)
1724 changed |= redirect_jump (insn, ultimate);
1730 /* @@ This needs a bit of work before it will be right.
1732 Any type of comparison can be accepted for the first and
1733 second compare. When rewriting the first jump, we must
1734 compute the what conditions can reach label3, and use the
1735 appropriate code. We can not simply reverse/swap the code
1736 of the first jump. In some cases, the second jump must be
1740 < == converts to > ==
1741 < != converts to == >
1744 If the code is written to only accept an '==' test for the second
1745 compare, then all that needs to be done is to swap the condition
1746 of the first branch.
1748 It is questionable whether we want this optimization anyways,
1749 since if the user wrote code like this because he/she knew that
1750 the jump to label1 is taken most of the time, then rewriting
1751 this gives slower code. */
1752 /* @@ This should call get_condition to find the values being
1753 compared, instead of looking for a COMPARE insn when HAVE_cc0
1754 is not defined. This would allow it to work on the m88k. */
1755 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1756 is not defined and the condition is tested by a separate compare
1757 insn. This is because the code below assumes that the result
1758 of the compare dies in the following branch. */
1760 /* Simplify test a ~= b
1774 where ~= is an inequality, e.g. >, and ~~= is the swapped
1777 We recognize this case scanning backwards.
1779 TEMP is the conditional jump to `label2';
1780 TEMP1 is the test for `a == b';
1781 TEMP2 is the conditional jump to `label1';
1782 TEMP3 is the test for `a ~= b'. */
1783 else if (this_is_simplejump
1784 && (temp = prev_active_insn (insn))
1785 && no_labels_between_p (temp, insn)
1786 && condjump_p (temp)
1787 && (temp1 = prev_active_insn (temp))
1788 && no_labels_between_p (temp1, temp)
1789 && GET_CODE (temp1) == INSN
1790 && GET_CODE (PATTERN (temp1)) == SET
1792 && sets_cc0_p (PATTERN (temp1)) == 1
1794 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1795 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1796 && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1798 && (temp2 = prev_active_insn (temp1))
1799 && no_labels_between_p (temp2, temp1)
1800 && condjump_p (temp2)
1801 && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
1802 && (temp3 = prev_active_insn (temp2))
1803 && no_labels_between_p (temp3, temp2)
1804 && GET_CODE (PATTERN (temp3)) == SET
1805 && rtx_equal_p (SET_DEST (PATTERN (temp3)),
1806 SET_DEST (PATTERN (temp1)))
1807 && rtx_equal_p (SET_SRC (PATTERN (temp1)),
1808 SET_SRC (PATTERN (temp3)))
1809 && ! inequality_comparisons_p (PATTERN (temp))
1810 && inequality_comparisons_p (PATTERN (temp2)))
1812 rtx fallthrough_label = JUMP_LABEL (temp2);
1814 ++LABEL_NUSES (fallthrough_label);
1815 if (swap_jump (temp2, JUMP_LABEL (insn)))
1821 if (--LABEL_NUSES (fallthrough_label) == 0)
1822 delete_insn (fallthrough_label);
1825 /* Simplify if (...) {... x = 1;} if (x) ...
1827 We recognize this case backwards.
1829 TEMP is the test of `x';
1830 TEMP1 is the assignment to `x' at the end of the
1831 previous statement. */
1832 /* @@ This should call get_condition to find the values being
1833 compared, instead of looking for a COMPARE insn when HAVE_cc0
1834 is not defined. This would allow it to work on the m88k. */
1835 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1836 is not defined and the condition is tested by a separate compare
1837 insn. This is because the code below assumes that the result
1838 of the compare dies in the following branch. */
1840 /* ??? This has to be turned off. The problem is that the
1841 unconditional jump might indirectly end up branching to the
1842 label between TEMP1 and TEMP. We can't detect this, in general,
1843 since it may become a jump to there after further optimizations.
1844 If that jump is done, it will be deleted, so we will retry
1845 this optimization in the next pass, thus an infinite loop.
1847 The present code prevents this by putting the jump after the
1848 label, but this is not logically correct. */
1850 else if (this_is_condjump
1851 /* Safe to skip USE and CLOBBER insns here
1852 since they will not be deleted. */
1853 && (temp = prev_active_insn (insn))
1854 && no_labels_between_p (temp, insn)
1855 && GET_CODE (temp) == INSN
1856 && GET_CODE (PATTERN (temp)) == SET
1858 && sets_cc0_p (PATTERN (temp)) == 1
1859 && GET_CODE (SET_SRC (PATTERN (temp))) == REG
1861 /* Temp must be a compare insn, we can not accept a register
1862 to register move here, since it may not be simply a
1864 && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
1865 && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
1866 && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
1867 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1868 && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
1870 /* May skip USE or CLOBBER insns here
1871 for checking for opportunity, since we
1872 take care of them later. */
1873 && (temp1 = prev_active_insn (temp))
1874 && GET_CODE (temp1) == INSN
1875 && GET_CODE (PATTERN (temp1)) == SET
1877 && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
1879 && (XEXP (SET_SRC (PATTERN (temp)), 0)
1880 == SET_DEST (PATTERN (temp1)))
1882 && CONSTANT_P (SET_SRC (PATTERN (temp1)))
1883 /* If this isn't true, cse will do the job. */
1884 && ! no_labels_between_p (temp1, temp))
1886 /* Get the if_then_else from the condjump. */
1887 rtx choice = SET_SRC (PATTERN (insn));
1888 if (GET_CODE (choice) == IF_THEN_ELSE
1889 && (GET_CODE (XEXP (choice, 0)) == EQ
1890 || GET_CODE (XEXP (choice, 0)) == NE))
1892 int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
1897 /* Get the place that condjump will jump to
1898 if it is reached from here. */
1899 if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
1901 ultimate = XEXP (choice, 1);
1903 ultimate = XEXP (choice, 2);
1904 /* Get it as a CODE_LABEL. */
1905 if (ultimate == pc_rtx)
1906 ultimate = get_label_after (insn);
1908 /* Get the label out of the LABEL_REF. */
1909 ultimate = XEXP (ultimate, 0);
1911 /* Insert the jump immediately before TEMP, specifically
1912 after the label that is between TEMP1 and TEMP. */
1913 last_insn = PREV_INSN (temp);
1915 /* If we would be branching to the next insn, the jump
1916 would immediately be deleted and the re-inserted in
1917 a subsequent pass over the code. So don't do anything
1919 if (next_active_insn (last_insn)
1920 != next_active_insn (ultimate))
1922 emit_barrier_after (last_insn);
1923 p = emit_jump_insn_after (gen_jump (ultimate),
1925 JUMP_LABEL (p) = ultimate;
1926 ++LABEL_NUSES (ultimate);
1927 if (INSN_UID (ultimate) < max_jump_chain
1928 && INSN_CODE (p) < max_jump_chain)
1930 jump_chain[INSN_UID (p)]
1931 = jump_chain[INSN_UID (ultimate)];
1932 jump_chain[INSN_UID (ultimate)] = p;
1941 /* Detect a conditional jump jumping over an unconditional trap. */
1943 && this_is_condjump && ! this_is_simplejump
1944 && reallabelprev != 0
1945 && GET_CODE (reallabelprev) == INSN
1946 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
1947 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
1948 && prev_active_insn (reallabelprev) == insn
1949 && no_labels_between_p (insn, reallabelprev)
1950 && (temp2 = get_condition (insn, &temp4))
1951 && can_reverse_comparison_p (temp2, insn))
1953 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
1954 XEXP (temp2, 0), XEXP (temp2, 1),
1955 TRAP_CODE (PATTERN (reallabelprev)));
1959 emit_insn_before (new, temp4);
1960 delete_insn (reallabelprev);
1966 /* Detect a jump jumping to an unconditional trap. */
1967 else if (HAVE_trap && this_is_condjump
1968 && (temp = next_active_insn (JUMP_LABEL (insn)))
1969 && GET_CODE (temp) == INSN
1970 && GET_CODE (PATTERN (temp)) == TRAP_IF
1971 && (this_is_simplejump
1972 || (temp2 = get_condition (insn, &temp4))))
1974 rtx tc = TRAP_CONDITION (PATTERN (temp));
1976 if (tc == const_true_rtx
1977 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
1980 /* Replace an unconditional jump to a trap with a trap. */
1981 if (this_is_simplejump)
1983 emit_barrier_after (emit_insn_before (gen_trap (), insn));
1988 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
1990 TRAP_CODE (PATTERN (temp)));
1993 emit_insn_before (new, temp4);
1999 /* If the trap condition and jump condition are mutually
2000 exclusive, redirect the jump to the following insn. */
2001 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
2002 && ! this_is_simplejump
2003 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
2004 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
2005 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
2006 && redirect_jump (insn, get_label_after (temp)))
2015 /* Detect a jump to a jump. */
2017 /* Look for if (foo) bar; else break; */
2018 /* The insns look like this:
2019 insn = condjump label1;
2020 ...range1 (some insns)...
2023 ...range2 (some insns)...
2024 jump somewhere unconditionally
2027 rtx label1 = next_label (insn);
2028 rtx range1end = label1 ? prev_active_insn (label1) : 0;
2029 /* Don't do this optimization on the first round, so that
2030 jump-around-a-jump gets simplified before we ask here
2031 whether a jump is unconditional.
2033 Also don't do it when we are called after reload since
2034 it will confuse reorg. */
2036 && (reload_completed ? ! flag_delayed_branch : 1)
2037 /* Make sure INSN is something we can invert. */
2038 && condjump_p (insn)
2040 && JUMP_LABEL (insn) == label1
2041 && LABEL_NUSES (label1) == 1
2042 && GET_CODE (range1end) == JUMP_INSN
2043 && simplejump_p (range1end))
2045 rtx label2 = next_label (label1);
2046 rtx range2end = label2 ? prev_active_insn (label2) : 0;
2047 if (range1end != range2end
2048 && JUMP_LABEL (range1end) == label2
2049 && GET_CODE (range2end) == JUMP_INSN
2050 && GET_CODE (NEXT_INSN (range2end)) == BARRIER
2051 /* Invert the jump condition, so we
2052 still execute the same insns in each case. */
2053 && invert_jump (insn, label1))
2055 rtx range1beg = next_active_insn (insn);
2056 rtx range2beg = next_active_insn (label1);
2057 rtx range1after, range2after;
2058 rtx range1before, range2before;
2061 /* Include in each range any notes before it, to be
2062 sure that we get the line number note if any, even
2063 if there are other notes here. */
2064 while (PREV_INSN (range1beg)
2065 && GET_CODE (PREV_INSN (range1beg)) == NOTE)
2066 range1beg = PREV_INSN (range1beg);
2068 while (PREV_INSN (range2beg)
2069 && GET_CODE (PREV_INSN (range2beg)) == NOTE)
2070 range2beg = PREV_INSN (range2beg);
2072 /* Don't move NOTEs for blocks or loops; shift them
2073 outside the ranges, where they'll stay put. */
2074 range1beg = squeeze_notes (range1beg, range1end);
2075 range2beg = squeeze_notes (range2beg, range2end);
2077 /* Get current surrounds of the 2 ranges. */
2078 range1before = PREV_INSN (range1beg);
2079 range2before = PREV_INSN (range2beg);
2080 range1after = NEXT_INSN (range1end);
2081 range2after = NEXT_INSN (range2end);
2083 /* Splice range2 where range1 was. */
2084 NEXT_INSN (range1before) = range2beg;
2085 PREV_INSN (range2beg) = range1before;
2086 NEXT_INSN (range2end) = range1after;
2087 PREV_INSN (range1after) = range2end;
2088 /* Splice range1 where range2 was. */
2089 NEXT_INSN (range2before) = range1beg;
2090 PREV_INSN (range1beg) = range2before;
2091 NEXT_INSN (range1end) = range2after;
2092 PREV_INSN (range2after) = range1end;
2094 /* Check for loop notes between the end of
2095 range2, and the next code label. If there is one,
2096 then what we have really seen is
2097 if (foo) break; end_of_loop;
2098 and moved the break sequence outside the loop.
2099 We must move LOOP_END, LOOP_VTOP and LOOP_CONT
2100 notes (in order) to where the loop really ends now,
2101 or we will confuse loop optimization. Stop if we
2102 find a LOOP_BEG note first, since we don't want to
2103 move the notes in that case. */
2104 for (;range2after != label2; range2after = rangenext)
2106 rangenext = NEXT_INSN (range2after);
2107 if (GET_CODE (range2after) == NOTE)
2109 int kind = NOTE_LINE_NUMBER (range2after);
2110 if (kind == NOTE_INSN_LOOP_END
2111 || kind == NOTE_INSN_LOOP_VTOP
2112 || kind == NOTE_INSN_LOOP_CONT)
2114 NEXT_INSN (PREV_INSN (range2after))
2116 PREV_INSN (rangenext)
2117 = PREV_INSN (range2after);
2118 PREV_INSN (range2after)
2119 = PREV_INSN (range1beg);
2120 NEXT_INSN (range2after) = range1beg;
2121 NEXT_INSN (PREV_INSN (range1beg))
2123 PREV_INSN (range1beg) = range2after;
2125 else if (NOTE_LINE_NUMBER (range2after)
2126 == NOTE_INSN_LOOP_BEG)
2136 /* Now that the jump has been tensioned,
2137 try cross jumping: check for identical code
2138 before the jump and before its target label. */
2140 /* First, cross jumping of conditional jumps: */
2142 if (cross_jump && condjump_p (insn))
2144 rtx newjpos, newlpos;
2145 rtx x = prev_real_insn (JUMP_LABEL (insn));
2147 /* A conditional jump may be crossjumped
2148 only if the place it jumps to follows
2149 an opposing jump that comes back here. */
2151 if (x != 0 && ! jump_back_p (x, insn))
2152 /* We have no opposing jump;
2153 cannot cross jump this insn. */
2157 /* TARGET is nonzero if it is ok to cross jump
2158 to code before TARGET. If so, see if matches. */
2160 find_cross_jump (insn, x, 2,
2161 &newjpos, &newlpos);
2165 do_cross_jump (insn, newjpos, newlpos);
2166 /* Make the old conditional jump
2167 into an unconditional one. */
2168 SET_SRC (PATTERN (insn))
2169 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2170 INSN_CODE (insn) = -1;
2171 emit_barrier_after (insn);
2172 /* Add to jump_chain unless this is a new label
2173 whose UID is too large. */
2174 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2176 jump_chain[INSN_UID (insn)]
2177 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2178 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2185 /* Cross jumping of unconditional jumps:
2186 a few differences. */
2188 if (cross_jump && simplejump_p (insn))
2190 rtx newjpos, newlpos;
2195 /* TARGET is nonzero if it is ok to cross jump
2196 to code before TARGET. If so, see if matches. */
2197 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2198 &newjpos, &newlpos);
2200 /* If cannot cross jump to code before the label,
2201 see if we can cross jump to another jump to
2203 /* Try each other jump to this label. */
2204 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2205 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2206 target != 0 && newjpos == 0;
2207 target = jump_chain[INSN_UID (target)])
2209 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2210 /* Ignore TARGET if it's deleted. */
2211 && ! INSN_DELETED_P (target))
2212 find_cross_jump (insn, target, 2,
2213 &newjpos, &newlpos);
2217 do_cross_jump (insn, newjpos, newlpos);
2223 /* This code was dead in the previous jump.c! */
2224 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2226 /* Return insns all "jump to the same place"
2227 so we can cross-jump between any two of them. */
2229 rtx newjpos, newlpos, target;
2233 /* If cannot cross jump to code before the label,
2234 see if we can cross jump to another jump to
2236 /* Try each other jump to this label. */
2237 for (target = jump_chain[0];
2238 target != 0 && newjpos == 0;
2239 target = jump_chain[INSN_UID (target)])
2241 && ! INSN_DELETED_P (target)
2242 && GET_CODE (PATTERN (target)) == RETURN)
2243 find_cross_jump (insn, target, 2,
2244 &newjpos, &newlpos);
2248 do_cross_jump (insn, newjpos, newlpos);
2259 /* Delete extraneous line number notes.
2260 Note that two consecutive notes for different lines are not really
2261 extraneous. There should be some indication where that line belonged,
2262 even if it became empty. */
2267 for (insn = f; insn; insn = NEXT_INSN (insn))
2268 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2270 /* Delete this note if it is identical to previous note. */
2272 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2273 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2286 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2287 in front of it. If the machine allows it at this point (we might be
2288 after reload for a leaf routine), it will improve optimization for it
2289 to be there. We do this both here and at the start of this pass since
2290 the RETURN might have been deleted by some of our optimizations. */
2291 insn = get_last_insn ();
2292 while (insn && GET_CODE (insn) == NOTE)
2293 insn = PREV_INSN (insn);
2295 if (insn && GET_CODE (insn) != BARRIER)
2297 emit_jump_insn (gen_return ());
2303 /* CAN_REACH_END is persistent for each function. Once set it should
2304 not be cleared. This is especially true for the case where we
2305 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2306 the front-end before compiling each function. */
2307 if (calculate_can_reach_end (last_insn, 0, 1))
2316 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2317 notes whose labels don't occur in the insn any more. Returns the
2318 largest INSN_UID found. */
2323 int largest_uid = 0;
2326 for (insn = f; insn; insn = NEXT_INSN (insn))
2328 if (GET_CODE (insn) == CODE_LABEL)
2329 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
2330 else if (GET_CODE (insn) == JUMP_INSN)
2331 JUMP_LABEL (insn) = 0;
2332 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2336 for (note = REG_NOTES (insn); note; note = next)
2338 next = XEXP (note, 1);
2339 if (REG_NOTE_KIND (note) == REG_LABEL
2340 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
2341 remove_note (insn, note);
2344 if (INSN_UID (insn) > largest_uid)
2345 largest_uid = INSN_UID (insn);
2351 /* Delete insns following barriers, up to next label.
2353 Also delete no-op jumps created by gcse. */
2355 delete_barrier_successors (f)
2360 for (insn = f; insn;)
2362 if (GET_CODE (insn) == BARRIER)
2364 insn = NEXT_INSN (insn);
2366 never_reached_warning (insn);
2368 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
2370 if (GET_CODE (insn) == NOTE
2371 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2372 insn = NEXT_INSN (insn);
2374 insn = delete_insn (insn);
2376 /* INSN is now the code_label. */
2378 /* Also remove (set (pc) (pc)) insns which can be created by
2379 gcse. We eliminate such insns now to avoid having them
2380 cause problems later. */
2381 else if (GET_CODE (insn) == JUMP_INSN
2382 && GET_CODE (PATTERN (insn)) == SET
2383 && SET_SRC (PATTERN (insn)) == pc_rtx
2384 && SET_DEST (PATTERN (insn)) == pc_rtx)
2385 insn = delete_insn (insn);
2388 insn = NEXT_INSN (insn);
2392 /* Mark the label each jump jumps to.
2393 Combine consecutive labels, and count uses of labels.
2395 For each label, make a chain (using `jump_chain')
2396 of all the *unconditional* jumps that jump to it;
2397 also make a chain of all returns.
2399 CROSS_JUMP indicates whether we are doing cross jumping
2400 and if we are whether we will be paying attention to
2401 death notes or not. */
2404 mark_all_labels (f, cross_jump)
2410 for (insn = f; insn; insn = NEXT_INSN (insn))
2411 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2413 mark_jump_label (PATTERN (insn), insn, cross_jump);
2414 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
2416 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2418 jump_chain[INSN_UID (insn)]
2419 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2420 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2422 if (GET_CODE (PATTERN (insn)) == RETURN)
2424 jump_chain[INSN_UID (insn)] = jump_chain[0];
2425 jump_chain[0] = insn;
2431 /* Delete all labels already not referenced.
2432 Also find and return the last insn. */
2435 delete_unreferenced_labels (f)
2438 rtx final = NULL_RTX;
2441 for (insn = f; insn; )
2443 if (GET_CODE (insn) == CODE_LABEL
2444 && LABEL_NUSES (insn) == 0
2445 && LABEL_ALTERNATE_NAME (insn) == NULL)
2446 insn = delete_insn (insn);
2450 insn = NEXT_INSN (insn);
2457 /* Delete various simple forms of moves which have no necessary
2461 delete_noop_moves (f)
2466 for (insn = f; insn; )
2468 next = NEXT_INSN (insn);
2470 if (GET_CODE (insn) == INSN)
2472 register rtx body = PATTERN (insn);
2474 /* Combine stack_adjusts with following push_insns. */
2475 #ifdef PUSH_ROUNDING
2476 if (GET_CODE (body) == SET
2477 && SET_DEST (body) == stack_pointer_rtx
2478 && GET_CODE (SET_SRC (body)) == PLUS
2479 && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
2480 && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
2481 && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
2484 rtx stack_adjust_insn = insn;
2485 int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
2486 int total_pushed = 0;
2489 /* Find all successive push insns. */
2491 /* Don't convert more than three pushes;
2492 that starts adding too many displaced addresses
2493 and the whole thing starts becoming a losing
2498 p = next_nonnote_insn (p);
2499 if (p == 0 || GET_CODE (p) != INSN)
2501 pbody = PATTERN (p);
2502 if (GET_CODE (pbody) != SET)
2504 dest = SET_DEST (pbody);
2505 /* Allow a no-op move between the adjust and the push. */
2506 if (GET_CODE (dest) == REG
2507 && GET_CODE (SET_SRC (pbody)) == REG
2508 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2510 if (! (GET_CODE (dest) == MEM
2511 && GET_CODE (XEXP (dest, 0)) == POST_INC
2512 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2515 if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
2516 > stack_adjust_amount)
2518 total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2521 /* Discard the amount pushed from the stack adjust;
2522 maybe eliminate it entirely. */
2523 if (total_pushed >= stack_adjust_amount)
2525 delete_computation (stack_adjust_insn);
2526 total_pushed = stack_adjust_amount;
2529 XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
2530 = GEN_INT (stack_adjust_amount - total_pushed);
2532 /* Change the appropriate push insns to ordinary stores. */
2534 while (total_pushed > 0)
2537 p = next_nonnote_insn (p);
2538 if (GET_CODE (p) != INSN)
2540 pbody = PATTERN (p);
2541 if (GET_CODE (pbody) != SET)
2543 dest = SET_DEST (pbody);
2544 /* Allow a no-op move between the adjust and the push. */
2545 if (GET_CODE (dest) == REG
2546 && GET_CODE (SET_SRC (pbody)) == REG
2547 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2549 if (! (GET_CODE (dest) == MEM
2550 && GET_CODE (XEXP (dest, 0)) == POST_INC
2551 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2553 total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2554 /* If this push doesn't fully fit in the space
2555 of the stack adjust that we deleted,
2556 make another stack adjust here for what we
2557 didn't use up. There should be peepholes
2558 to recognize the resulting sequence of insns. */
2559 if (total_pushed < 0)
2561 emit_insn_before (gen_add2_insn (stack_pointer_rtx,
2562 GEN_INT (- total_pushed)),
2567 = plus_constant (stack_pointer_rtx, total_pushed);
2572 /* Detect and delete no-op move instructions
2573 resulting from not allocating a parameter in a register. */
2575 if (GET_CODE (body) == SET
2576 && (SET_DEST (body) == SET_SRC (body)
2577 || (GET_CODE (SET_DEST (body)) == MEM
2578 && GET_CODE (SET_SRC (body)) == MEM
2579 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
2580 && ! (GET_CODE (SET_DEST (body)) == MEM
2581 && MEM_VOLATILE_P (SET_DEST (body)))
2582 && ! (GET_CODE (SET_SRC (body)) == MEM
2583 && MEM_VOLATILE_P (SET_SRC (body))))
2584 delete_computation (insn);
2586 /* Detect and ignore no-op move instructions
2587 resulting from smart or fortuitous register allocation. */
2589 else if (GET_CODE (body) == SET)
2591 int sreg = true_regnum (SET_SRC (body));
2592 int dreg = true_regnum (SET_DEST (body));
2594 if (sreg == dreg && sreg >= 0)
2596 else if (sreg >= 0 && dreg >= 0)
2599 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
2600 sreg, NULL_PTR, dreg,
2601 GET_MODE (SET_SRC (body)));
2604 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
2606 /* DREG may have been the target of a REG_DEAD note in
2607 the insn which makes INSN redundant. If so, reorg
2608 would still think it is dead. So search for such a
2609 note and delete it if we find it. */
2610 if (! find_regno_note (insn, REG_UNUSED, dreg))
2611 for (trial = prev_nonnote_insn (insn);
2612 trial && GET_CODE (trial) != CODE_LABEL;
2613 trial = prev_nonnote_insn (trial))
2614 if (find_regno_note (trial, REG_DEAD, dreg))
2616 remove_death (dreg, trial);
2620 /* Deleting insn could lose a death-note for SREG. */
2621 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
2623 /* Change this into a USE so that we won't emit
2624 code for it, but still can keep the note. */
2626 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
2627 INSN_CODE (insn) = -1;
2628 /* Remove all reg notes but the REG_DEAD one. */
2629 REG_NOTES (insn) = trial;
2630 XEXP (trial, 1) = NULL_RTX;
2636 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
2637 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
2639 GET_MODE (SET_DEST (body))))
2641 /* This handles the case where we have two consecutive
2642 assignments of the same constant to pseudos that didn't
2643 get a hard reg. Each SET from the constant will be
2644 converted into a SET of the spill register and an
2645 output reload will be made following it. This produces
2646 two loads of the same constant into the same spill
2651 /* Look back for a death note for the first reg.
2652 If there is one, it is no longer accurate. */
2653 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
2655 if ((GET_CODE (in_insn) == INSN
2656 || GET_CODE (in_insn) == JUMP_INSN)
2657 && find_regno_note (in_insn, REG_DEAD, dreg))
2659 remove_death (dreg, in_insn);
2662 in_insn = PREV_INSN (in_insn);
2665 /* Delete the second load of the value. */
2669 else if (GET_CODE (body) == PARALLEL)
2671 /* If each part is a set between two identical registers or
2672 a USE or CLOBBER, delete the insn. */
2676 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
2678 tem = XVECEXP (body, 0, i);
2679 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
2682 if (GET_CODE (tem) != SET
2683 || (sreg = true_regnum (SET_SRC (tem))) < 0
2684 || (dreg = true_regnum (SET_DEST (tem))) < 0
2692 /* Also delete insns to store bit fields if they are no-ops. */
2693 /* Not worth the hair to detect this in the big-endian case. */
2694 else if (! BYTES_BIG_ENDIAN
2695 && GET_CODE (body) == SET
2696 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
2697 && XEXP (SET_DEST (body), 2) == const0_rtx
2698 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
2699 && ! (GET_CODE (SET_SRC (body)) == MEM
2700 && MEM_VOLATILE_P (SET_SRC (body))))
2707 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2708 If so indicate that this function can drop off the end by returning
2711 CHECK_DELETED indicates whether we must check if the note being
2712 searched for has the deleted flag set.
2714 DELETE_FINAL_NOTE indicates whether we should delete the note
2718 calculate_can_reach_end (last, check_deleted, delete_final_note)
2721 int delete_final_note;
2726 while (insn != NULL_RTX)
2730 /* One label can follow the end-note: the return label. */
2731 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2733 /* Ordinary insns can follow it if returning a structure. */
2734 else if (GET_CODE (insn) == INSN)
2736 /* If machine uses explicit RETURN insns, no epilogue,
2737 then one of them follows the note. */
2738 else if (GET_CODE (insn) == JUMP_INSN
2739 && GET_CODE (PATTERN (insn)) == RETURN)
2741 /* A barrier can follow the return insn. */
2742 else if (GET_CODE (insn) == BARRIER)
2744 /* Other kinds of notes can follow also. */
2745 else if (GET_CODE (insn) == NOTE
2746 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2752 insn = PREV_INSN (insn);
2755 /* See if we backed up to the appropriate type of note. */
2756 if (insn != NULL_RTX
2757 && GET_CODE (insn) == NOTE
2758 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
2759 && (check_deleted == 0
2760 || ! INSN_DELETED_P (insn)))
2762 if (delete_final_note)
2770 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2771 jump. Assume that this unconditional jump is to the exit test code. If
2772 the code is sufficiently simple, make a copy of it before INSN,
2773 followed by a jump to the exit of the loop. Then delete the unconditional
2776 Return 1 if we made the change, else 0.
2778 This is only safe immediately after a regscan pass because it uses the
2779 values of regno_first_uid and regno_last_uid. */
2782 duplicate_loop_exit_test (loop_start)
2785 rtx insn, set, reg, p, link;
2786 rtx copy = 0, first_copy = 0;
2788 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2790 int max_reg = max_reg_num ();
2793 /* Scan the exit code. We do not perform this optimization if any insn:
2797 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2798 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2799 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2802 We also do not do this if we find an insn with ASM_OPERANDS. While
2803 this restriction should not be necessary, copying an insn with
2804 ASM_OPERANDS can confuse asm_noperands in some cases.
2806 Also, don't do this if the exit code is more than 20 insns. */
2808 for (insn = exitcode;
2810 && ! (GET_CODE (insn) == NOTE
2811 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2812 insn = NEXT_INSN (insn))
2814 switch (GET_CODE (insn))
2820 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2821 a jump immediately after the loop start that branches outside
2822 the loop but within an outer loop, near the exit test.
2823 If we copied this exit test and created a phony
2824 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2825 before the exit test look like these could be safely moved
2826 out of the loop even if they actually may be never executed.
2827 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2829 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2830 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2834 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2835 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2836 /* If we were to duplicate this code, we would not move
2837 the BLOCK notes, and so debugging the moved code would
2838 be difficult. Thus, we only move the code with -O2 or
2845 /* The code below would grossly mishandle REG_WAS_0 notes,
2846 so get rid of them here. */
2847 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
2848 remove_note (insn, p);
2849 if (++num_insns > 20
2850 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2851 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
2859 /* Unless INSN is zero, we can do the optimization. */
2865 /* See if any insn sets a register only used in the loop exit code and
2866 not a user variable. If so, replace it with a new register. */
2867 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2868 if (GET_CODE (insn) == INSN
2869 && (set = single_set (insn)) != 0
2870 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2871 || (GET_CODE (reg) == SUBREG
2872 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2873 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2874 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2876 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2877 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2882 /* We can do the replacement. Allocate reg_map if this is the
2883 first replacement we found. */
2885 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
2887 REG_LOOP_TEST_P (reg) = 1;
2889 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2893 /* Now copy each insn. */
2894 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2896 switch (GET_CODE (insn))
2899 copy = emit_barrier_before (loop_start);
2902 /* Only copy line-number notes. */
2903 if (NOTE_LINE_NUMBER (insn) >= 0)
2905 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2906 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2911 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
2913 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2915 mark_jump_label (PATTERN (copy), copy, 0);
2917 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2919 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2920 if (REG_NOTE_KIND (link) != REG_LABEL)
2922 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2925 if (reg_map && REG_NOTES (copy))
2926 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2930 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
2932 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2933 mark_jump_label (PATTERN (copy), copy, 0);
2934 if (REG_NOTES (insn))
2936 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
2938 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2941 /* If this is a simple jump, add it to the jump chain. */
2943 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2944 && simplejump_p (copy))
2946 jump_chain[INSN_UID (copy)]
2947 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2948 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2956 /* Record the first insn we copied. We need it so that we can
2957 scan the copied insns for new pseudo registers. */
2962 /* Now clean up by emitting a jump to the end label and deleting the jump
2963 at the start of the loop. */
2964 if (! copy || GET_CODE (copy) != BARRIER)
2966 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2969 /* Record the first insn we copied. We need it so that we can
2970 scan the copied insns for new pseudo registers. This may not
2971 be strictly necessary since we should have copied at least one
2972 insn above. But I am going to be safe. */
2976 mark_jump_label (PATTERN (copy), copy, 0);
2977 if (INSN_UID (copy) < max_jump_chain
2978 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2980 jump_chain[INSN_UID (copy)]
2981 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2982 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2984 emit_barrier_before (loop_start);
2987 /* Now scan from the first insn we copied to the last insn we copied
2988 (copy) for new pseudo registers. Do this after the code to jump to
2989 the end label since that might create a new pseudo too. */
2990 reg_scan_update (first_copy, copy, max_reg);
2992 /* Mark the exit code as the virtual top of the converted loop. */
2993 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2995 delete_insn (next_nonnote_insn (loop_start));
3004 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
3005 loop-end notes between START and END out before START. Assume that
3006 END is not such a note. START may be such a note. Returns the value
3007 of the new starting insn, which may be different if the original start
3011 squeeze_notes (start, end)
3017 for (insn = start; insn != end; insn = next)
3019 next = NEXT_INSN (insn);
3020 if (GET_CODE (insn) == NOTE
3021 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
3022 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
3023 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
3024 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
3025 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
3026 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
3032 rtx prev = PREV_INSN (insn);
3033 PREV_INSN (insn) = PREV_INSN (start);
3034 NEXT_INSN (insn) = start;
3035 NEXT_INSN (PREV_INSN (insn)) = insn;
3036 PREV_INSN (NEXT_INSN (insn)) = insn;
3037 NEXT_INSN (prev) = next;
3038 PREV_INSN (next) = prev;
3046 /* Compare the instructions before insn E1 with those before E2
3047 to find an opportunity for cross jumping.
3048 (This means detecting identical sequences of insns followed by
3049 jumps to the same place, or followed by a label and a jump
3050 to that label, and replacing one with a jump to the other.)
3052 Assume E1 is a jump that jumps to label E2
3053 (that is not always true but it might as well be).
3054 Find the longest possible equivalent sequences
3055 and store the first insns of those sequences into *F1 and *F2.
3056 Store zero there if no equivalent preceding instructions are found.
3058 We give up if we find a label in stream 1.
3059 Actually we could transfer that label into stream 2. */
3062 find_cross_jump (e1, e2, minimum, f1, f2)
3067 register rtx i1 = e1, i2 = e2;
3068 register rtx p1, p2;
3071 rtx last1 = 0, last2 = 0;
3072 rtx afterlast1 = 0, afterlast2 = 0;
3079 i1 = prev_nonnote_insn (i1);
3081 i2 = PREV_INSN (i2);
3082 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
3083 i2 = PREV_INSN (i2);
3088 /* Don't allow the range of insns preceding E1 or E2
3089 to include the other (E2 or E1). */
3090 if (i2 == e1 || i1 == e2)
3093 /* If we will get to this code by jumping, those jumps will be
3094 tensioned to go directly to the new label (before I2),
3095 so this cross-jumping won't cost extra. So reduce the minimum. */
3096 if (GET_CODE (i1) == CODE_LABEL)
3102 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
3105 /* Avoid moving insns across EH regions if either of the insns
3108 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
3109 && !in_same_eh_region (i1, i2))
3115 /* If this is a CALL_INSN, compare register usage information.
3116 If we don't check this on stack register machines, the two
3117 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3118 numbers of stack registers in the same basic block.
3119 If we don't check this on machines with delay slots, a delay slot may
3120 be filled that clobbers a parameter expected by the subroutine.
3122 ??? We take the simple route for now and assume that if they're
3123 equal, they were constructed identically. */
3125 if (GET_CODE (i1) == CALL_INSN
3126 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3127 CALL_INSN_FUNCTION_USAGE (i2)))
3131 /* If cross_jump_death_matters is not 0, the insn's mode
3132 indicates whether or not the insn contains any stack-like
3135 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
3137 /* If register stack conversion has already been done, then
3138 death notes must also be compared before it is certain that
3139 the two instruction streams match. */
3142 HARD_REG_SET i1_regset, i2_regset;
3144 CLEAR_HARD_REG_SET (i1_regset);
3145 CLEAR_HARD_REG_SET (i2_regset);
3147 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3148 if (REG_NOTE_KIND (note) == REG_DEAD
3149 && STACK_REG_P (XEXP (note, 0)))
3150 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3152 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3153 if (REG_NOTE_KIND (note) == REG_DEAD
3154 && STACK_REG_P (XEXP (note, 0)))
3155 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3157 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3166 /* Don't allow old-style asm or volatile extended asms to be accepted
3167 for cross jumping purposes. It is conceptually correct to allow
3168 them, since cross-jumping preserves the dynamic instruction order
3169 even though it is changing the static instruction order. However,
3170 if an asm is being used to emit an assembler pseudo-op, such as
3171 the MIPS `.set reorder' pseudo-op, then the static instruction order
3172 matters and it must be preserved. */
3173 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
3174 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
3175 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
3178 if (lose || GET_CODE (p1) != GET_CODE (p2)
3179 || ! rtx_renumbered_equal_p (p1, p2))
3181 /* The following code helps take care of G++ cleanups. */
3185 if (!lose && GET_CODE (p1) == GET_CODE (p2)
3186 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
3187 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
3188 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
3189 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
3190 /* If the equivalences are not to a constant, they may
3191 reference pseudos that no longer exist, so we can't
3193 && CONSTANT_P (XEXP (equiv1, 0))
3194 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3196 rtx s1 = single_set (i1);
3197 rtx s2 = single_set (i2);
3198 if (s1 != 0 && s2 != 0
3199 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3201 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3202 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3203 if (! rtx_renumbered_equal_p (p1, p2))
3205 else if (apply_change_group ())
3210 /* Insns fail to match; cross jumping is limited to the following
3214 /* Don't allow the insn after a compare to be shared by
3215 cross-jumping unless the compare is also shared.
3216 Here, if either of these non-matching insns is a compare,
3217 exclude the following insn from possible cross-jumping. */
3218 if (sets_cc0_p (p1) || sets_cc0_p (p2))
3219 last1 = afterlast1, last2 = afterlast2, ++minimum;
3222 /* If cross-jumping here will feed a jump-around-jump
3223 optimization, this jump won't cost extra, so reduce
3225 if (GET_CODE (i1) == JUMP_INSN
3227 && prev_real_insn (JUMP_LABEL (i1)) == e1)
3233 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3235 /* Ok, this insn is potentially includable in a cross-jump here. */
3236 afterlast1 = last1, afterlast2 = last2;
3237 last1 = i1, last2 = i2, --minimum;
3241 if (minimum <= 0 && last1 != 0 && last1 != e1)
3242 *f1 = last1, *f2 = last2;
3246 do_cross_jump (insn, newjpos, newlpos)
3247 rtx insn, newjpos, newlpos;
3249 /* Find an existing label at this point
3250 or make a new one if there is none. */
3251 register rtx label = get_label_before (newlpos);
3253 /* Make the same jump insn jump to the new point. */
3254 if (GET_CODE (PATTERN (insn)) == RETURN)
3256 /* Remove from jump chain of returns. */
3257 delete_from_jump_chain (insn);
3258 /* Change the insn. */
3259 PATTERN (insn) = gen_jump (label);
3260 INSN_CODE (insn) = -1;
3261 JUMP_LABEL (insn) = label;
3262 LABEL_NUSES (label)++;
3263 /* Add to new the jump chain. */
3264 if (INSN_UID (label) < max_jump_chain
3265 && INSN_UID (insn) < max_jump_chain)
3267 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
3268 jump_chain[INSN_UID (label)] = insn;
3272 redirect_jump (insn, label);
3274 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3275 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3276 the NEWJPOS stream. */
3278 while (newjpos != insn)
3282 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
3283 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
3284 || REG_NOTE_KIND (lnote) == REG_EQUIV)
3285 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
3286 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
3287 remove_note (newlpos, lnote);
3289 delete_insn (newjpos);
3290 newjpos = next_real_insn (newjpos);
3291 newlpos = next_real_insn (newlpos);
3295 /* Return the label before INSN, or put a new label there. */
3298 get_label_before (insn)
3303 /* Find an existing label at this point
3304 or make a new one if there is none. */
3305 label = prev_nonnote_insn (insn);
3307 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3309 rtx prev = PREV_INSN (insn);
3311 label = gen_label_rtx ();
3312 emit_label_after (label, prev);
3313 LABEL_NUSES (label) = 0;
3318 /* Return the label after INSN, or put a new label there. */
3321 get_label_after (insn)
3326 /* Find an existing label at this point
3327 or make a new one if there is none. */
3328 label = next_nonnote_insn (insn);
3330 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3332 label = gen_label_rtx ();
3333 emit_label_after (label, insn);
3334 LABEL_NUSES (label) = 0;
3339 /* Return 1 if INSN is a jump that jumps to right after TARGET
3340 only on the condition that TARGET itself would drop through.
3341 Assumes that TARGET is a conditional jump. */
3344 jump_back_p (insn, target)
3348 enum rtx_code codei, codet;
3350 if (simplejump_p (insn) || ! condjump_p (insn)
3351 || simplejump_p (target)
3352 || target != prev_real_insn (JUMP_LABEL (insn)))
3355 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
3356 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
3358 codei = GET_CODE (cinsn);
3359 codet = GET_CODE (ctarget);
3361 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
3363 if (! can_reverse_comparison_p (cinsn, insn))
3365 codei = reverse_condition (codei);
3368 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
3370 if (! can_reverse_comparison_p (ctarget, target))
3372 codet = reverse_condition (codet);
3375 return (codei == codet
3376 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
3377 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
3380 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3381 return non-zero if it is safe to reverse this comparison. It is if our
3382 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3383 this is known to be an integer comparison. */
3386 can_reverse_comparison_p (comparison, insn)
3392 /* If this is not actually a comparison, we can't reverse it. */
3393 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
3396 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3397 /* If this is an NE comparison, it is safe to reverse it to an EQ
3398 comparison and vice versa, even for floating point. If no operands
3399 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3400 always false and NE is always true, so the reversal is also valid. */
3402 || GET_CODE (comparison) == NE
3403 || GET_CODE (comparison) == EQ)
3406 arg0 = XEXP (comparison, 0);
3408 /* Make sure ARG0 is one of the actual objects being compared. If we
3409 can't do this, we can't be sure the comparison can be reversed.
3411 Handle cc0 and a MODE_CC register. */
3412 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3418 rtx prev = prev_nonnote_insn (insn);
3421 /* First see if the condition code mode alone if enough to say we can
3422 reverse the condition. If not, then search backwards for a set of
3423 ARG0. We do not need to check for an insn clobbering it since valid
3424 code will contain set a set with no intervening clobber. But
3425 stop when we reach a label. */
3426 #ifdef REVERSIBLE_CC_MODE
3427 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
3428 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
3432 for (prev = prev_nonnote_insn (insn);
3433 prev != 0 && GET_CODE (prev) != CODE_LABEL;
3434 prev = prev_nonnote_insn (prev))
3435 if ((set = single_set (prev)) != 0
3436 && rtx_equal_p (SET_DEST (set), arg0))
3438 arg0 = SET_SRC (set);
3440 if (GET_CODE (arg0) == COMPARE)
3441 arg0 = XEXP (arg0, 0);
3446 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3447 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3448 return (GET_CODE (arg0) == CONST_INT
3449 || (GET_MODE (arg0) != VOIDmode
3450 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3451 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3454 /* Given an rtx-code for a comparison, return the code
3455 for the negated comparison.
3456 WATCH OUT! reverse_condition is not safe to use on a jump
3457 that might be acting on the results of an IEEE floating point comparison,
3458 because of the special treatment of non-signaling nans in comparisons.
3459 Use can_reverse_comparison_p to be sure. */
3462 reverse_condition (code)
3503 /* Similar, but return the code when two operands of a comparison are swapped.
3504 This IS safe for IEEE floating-point. */
3507 swap_condition (code)
3546 /* Given a comparison CODE, return the corresponding unsigned comparison.
3547 If CODE is an equality comparison or already an unsigned comparison,
3548 CODE is returned. */
3551 unsigned_condition (code)
3581 /* Similarly, return the signed version of a comparison. */
3584 signed_condition (code)
3614 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3615 truth of CODE1 implies the truth of CODE2. */
3618 comparison_dominates_p (code1, code2)
3619 enum rtx_code code1, code2;
3627 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
3632 if (code2 == LE || code2 == NE)
3637 if (code2 == GE || code2 == NE)
3642 if (code2 == LEU || code2 == NE)
3647 if (code2 == GEU || code2 == NE)
3658 /* Return 1 if INSN is an unconditional jump and nothing else. */
3664 return (GET_CODE (insn) == JUMP_INSN
3665 && GET_CODE (PATTERN (insn)) == SET
3666 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3667 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3670 /* Return nonzero if INSN is a (possibly) conditional jump
3671 and nothing more. */
3677 register rtx x = PATTERN (insn);
3679 if (GET_CODE (x) != SET
3680 || GET_CODE (SET_DEST (x)) != PC)
3684 if (GET_CODE (x) == LABEL_REF)
3686 else return (GET_CODE (x) == IF_THEN_ELSE
3687 && ((GET_CODE (XEXP (x, 2)) == PC
3688 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
3689 || GET_CODE (XEXP (x, 1)) == RETURN))
3690 || (GET_CODE (XEXP (x, 1)) == PC
3691 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
3692 || GET_CODE (XEXP (x, 2)) == RETURN))));
3697 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3701 condjump_in_parallel_p (insn)
3704 register rtx x = PATTERN (insn);
3706 if (GET_CODE (x) != PARALLEL)
3709 x = XVECEXP (x, 0, 0);
3711 if (GET_CODE (x) != SET)
3713 if (GET_CODE (SET_DEST (x)) != PC)
3715 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3717 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3719 if (XEXP (SET_SRC (x), 2) == pc_rtx
3720 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3721 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3723 if (XEXP (SET_SRC (x), 1) == pc_rtx
3724 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3725 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3730 /* Return the label of a conditional jump. */
3733 condjump_label (insn)
3736 register rtx x = PATTERN (insn);
3738 if (GET_CODE (x) == PARALLEL)
3739 x = XVECEXP (x, 0, 0);
3740 if (GET_CODE (x) != SET)
3742 if (GET_CODE (SET_DEST (x)) != PC)
3745 if (GET_CODE (x) == LABEL_REF)
3747 if (GET_CODE (x) != IF_THEN_ELSE)
3749 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
3751 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
3756 /* Return true if INSN is a (possibly conditional) return insn. */
3759 returnjump_p_1 (loc, data)
3761 void *data ATTRIBUTE_UNUSED;
3764 return GET_CODE (x) == RETURN;
3771 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
3774 /* Return true if INSN is a jump that only transfers control and
3783 if (GET_CODE (insn) != JUMP_INSN)
3786 set = single_set (insn);
3789 if (GET_CODE (SET_DEST (set)) != PC)
3791 if (side_effects_p (SET_SRC (set)))
3799 /* Return 1 if X is an RTX that does nothing but set the condition codes
3800 and CLOBBER or USE registers.
3801 Return -1 if X does explicitly set the condition codes,
3802 but also does other things. */
3806 rtx x ATTRIBUTE_UNUSED;
3808 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3810 if (GET_CODE (x) == PARALLEL)
3814 int other_things = 0;
3815 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3817 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3818 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3820 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3823 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3829 /* Follow any unconditional jump at LABEL;
3830 return the ultimate label reached by any such chain of jumps.
3831 If LABEL is not followed by a jump, return LABEL.
3832 If the chain loops or we can't find end, return LABEL,
3833 since that tells caller to avoid changing the insn.
3835 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3836 a USE or CLOBBER. */
3839 follow_jumps (label)
3844 register rtx value = label;
3849 && (insn = next_active_insn (value)) != 0
3850 && GET_CODE (insn) == JUMP_INSN
3851 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3852 || GET_CODE (PATTERN (insn)) == RETURN)
3853 && (next = NEXT_INSN (insn))
3854 && GET_CODE (next) == BARRIER);
3857 /* Don't chain through the insn that jumps into a loop
3858 from outside the loop,
3859 since that would create multiple loop entry jumps
3860 and prevent loop optimization. */
3862 if (!reload_completed)
3863 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3864 if (GET_CODE (tem) == NOTE
3865 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3866 /* ??? Optional. Disables some optimizations, but makes
3867 gcov output more accurate with -O. */
3868 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3871 /* If we have found a cycle, make the insn jump to itself. */
3872 if (JUMP_LABEL (insn) == label)
3875 tem = next_active_insn (JUMP_LABEL (insn));
3876 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3877 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3880 value = JUMP_LABEL (insn);
3887 /* Assuming that field IDX of X is a vector of label_refs,
3888 replace each of them by the ultimate label reached by it.
3889 Return nonzero if a change is made.
3890 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3893 tension_vector_labels (x, idx)
3899 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3901 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3902 register rtx nlabel = follow_jumps (olabel);
3903 if (nlabel && nlabel != olabel)
3905 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3906 ++LABEL_NUSES (nlabel);
3907 if (--LABEL_NUSES (olabel) == 0)
3908 delete_insn (olabel);
3915 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3916 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3917 in INSN, then store one of them in JUMP_LABEL (INSN).
3918 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3919 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3920 Also, when there are consecutive labels, canonicalize on the last of them.
3922 Note that two labels separated by a loop-beginning note
3923 must be kept distinct if we have not yet done loop-optimization,
3924 because the gap between them is where loop-optimize
3925 will want to move invariant code to. CROSS_JUMP tells us
3926 that loop-optimization is done with.
3928 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3929 two labels distinct if they are separated by only USE or CLOBBER insns. */
3932 mark_jump_label (x, insn, cross_jump)
3937 register RTX_CODE code = GET_CODE (x);
3939 register const char *fmt;
3955 /* If this is a constant-pool reference, see if it is a label. */
3956 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3957 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3958 mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
3963 rtx label = XEXP (x, 0);
3968 if (GET_CODE (label) != CODE_LABEL)
3971 /* Ignore references to labels of containing functions. */
3972 if (LABEL_REF_NONLOCAL_P (x))
3975 /* If there are other labels following this one,
3976 replace it with the last of the consecutive labels. */
3977 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3979 if (GET_CODE (next) == CODE_LABEL)
3981 else if (cross_jump && GET_CODE (next) == INSN
3982 && (GET_CODE (PATTERN (next)) == USE
3983 || GET_CODE (PATTERN (next)) == CLOBBER))
3985 else if (GET_CODE (next) != NOTE)
3987 else if (! cross_jump
3988 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3989 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3990 /* ??? Optional. Disables some optimizations, but
3991 makes gcov output more accurate with -O. */
3992 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3996 XEXP (x, 0) = label;
3997 if (! insn || ! INSN_DELETED_P (insn))
3998 ++LABEL_NUSES (label);
4002 if (GET_CODE (insn) == JUMP_INSN)
4003 JUMP_LABEL (insn) = label;
4005 /* If we've changed OLABEL and we had a REG_LABEL note
4006 for it, update it as well. */
4007 else if (label != olabel
4008 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
4009 XEXP (note, 0) = label;
4011 /* Otherwise, add a REG_LABEL note for LABEL unless there already
4013 else if (! find_reg_note (insn, REG_LABEL, label))
4015 /* This code used to ignore labels which refered to dispatch
4016 tables to avoid flow.c generating worse code.
4018 However, in the presense of global optimizations like
4019 gcse which call find_basic_blocks without calling
4020 life_analysis, not recording such labels will lead
4021 to compiler aborts because of inconsistencies in the
4022 flow graph. So we go ahead and record the label.
4024 It may also be the case that the optimization argument
4025 is no longer valid because of the more accurate cfg
4026 we build in find_basic_blocks -- it no longer pessimizes
4027 code when it finds a REG_LABEL note. */
4028 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
4035 /* Do walk the labels in a vector, but not the first operand of an
4036 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
4039 if (! INSN_DELETED_P (insn))
4041 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
4043 for (i = 0; i < XVECLEN (x, eltnum); i++)
4044 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
4052 fmt = GET_RTX_FORMAT (code);
4053 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4056 mark_jump_label (XEXP (x, i), insn, cross_jump);
4057 else if (fmt[i] == 'E')
4060 for (j = 0; j < XVECLEN (x, i); j++)
4061 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
4066 /* If all INSN does is set the pc, delete it,
4067 and delete the insn that set the condition codes for it
4068 if that's what the previous thing was. */
4074 register rtx set = single_set (insn);
4076 if (set && GET_CODE (SET_DEST (set)) == PC)
4077 delete_computation (insn);
4080 /* Verify INSN is a BARRIER and delete it. */
4083 delete_barrier (insn)
4086 if (GET_CODE (insn) != BARRIER)
4092 /* Recursively delete prior insns that compute the value (used only by INSN
4093 which the caller is deleting) stored in the register mentioned by NOTE
4094 which is a REG_DEAD note associated with INSN. */
4097 delete_prior_computation (note, insn)
4102 rtx reg = XEXP (note, 0);
4104 for (our_prev = prev_nonnote_insn (insn);
4105 our_prev && (GET_CODE (our_prev) == INSN
4106 || GET_CODE (our_prev) == CALL_INSN);
4107 our_prev = prev_nonnote_insn (our_prev))
4109 rtx pat = PATTERN (our_prev);
4111 /* If we reach a CALL which is not calling a const function
4112 or the callee pops the arguments, then give up. */
4113 if (GET_CODE (our_prev) == CALL_INSN
4114 && (! CONST_CALL_P (our_prev)
4115 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
4118 /* If we reach a SEQUENCE, it is too complex to try to
4119 do anything with it, so give up. */
4120 if (GET_CODE (pat) == SEQUENCE)
4123 if (GET_CODE (pat) == USE
4124 && GET_CODE (XEXP (pat, 0)) == INSN)
4125 /* reorg creates USEs that look like this. We leave them
4126 alone because reorg needs them for its own purposes. */
4129 if (reg_set_p (reg, pat))
4131 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
4134 if (GET_CODE (pat) == PARALLEL)
4136 /* If we find a SET of something else, we can't
4141 for (i = 0; i < XVECLEN (pat, 0); i++)
4143 rtx part = XVECEXP (pat, 0, i);
4145 if (GET_CODE (part) == SET
4146 && SET_DEST (part) != reg)
4150 if (i == XVECLEN (pat, 0))
4151 delete_computation (our_prev);
4153 else if (GET_CODE (pat) == SET
4154 && GET_CODE (SET_DEST (pat)) == REG)
4156 int dest_regno = REGNO (SET_DEST (pat));
4158 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4159 ? HARD_REGNO_NREGS (dest_regno,
4160 GET_MODE (SET_DEST (pat))) : 1);
4161 int regno = REGNO (reg);
4162 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
4163 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
4165 if (dest_regno >= regno
4166 && dest_endregno <= endregno)
4167 delete_computation (our_prev);
4169 /* We may have a multi-word hard register and some, but not
4170 all, of the words of the register are needed in subsequent
4171 insns. Write REG_UNUSED notes for those parts that were not
4173 else if (dest_regno <= regno
4174 && dest_endregno >= endregno)
4178 REG_NOTES (our_prev)
4179 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
4181 for (i = dest_regno; i < dest_endregno; i++)
4182 if (! find_regno_note (our_prev, REG_UNUSED, i))
4185 if (i == dest_endregno)
4186 delete_computation (our_prev);
4193 /* If PAT references the register that dies here, it is an
4194 additional use. Hence any prior SET isn't dead. However, this
4195 insn becomes the new place for the REG_DEAD note. */
4196 if (reg_overlap_mentioned_p (reg, pat))
4198 XEXP (note, 1) = REG_NOTES (our_prev);
4199 REG_NOTES (our_prev) = note;
4205 /* Delete INSN and recursively delete insns that compute values used only
4206 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4207 If we are running before flow.c, we need do nothing since flow.c will
4208 delete dead code. We also can't know if the registers being used are
4209 dead or not at this point.
4211 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4212 nothing other than set a register that dies in this insn, we can delete
4215 On machines with CC0, if CC0 is used in this insn, we may be able to
4216 delete the insn that set it. */
4219 delete_computation (insn)
4226 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
4228 rtx prev = prev_nonnote_insn (insn);
4229 /* We assume that at this stage
4230 CC's are always set explicitly
4231 and always immediately before the jump that
4232 will use them. So if the previous insn
4233 exists to set the CC's, delete it
4234 (unless it performs auto-increments, etc.). */
4235 if (prev && GET_CODE (prev) == INSN
4236 && sets_cc0_p (PATTERN (prev)))
4238 if (sets_cc0_p (PATTERN (prev)) > 0
4239 && ! side_effects_p (PATTERN (prev)))
4240 delete_computation (prev);
4242 /* Otherwise, show that cc0 won't be used. */
4243 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
4244 cc0_rtx, REG_NOTES (prev));
4249 #ifdef INSN_SCHEDULING
4250 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4251 reload has completed. The schedulers need to be fixed. Until
4252 they are, we must not rely on the death notes here. */
4253 if (reload_completed && flag_schedule_insns_after_reload)
4260 /* The REG_DEAD note may have been omitted for a register
4261 which is both set and used by the insn. */
4262 set = single_set (insn);
4263 if (set && GET_CODE (SET_DEST (set)) == REG)
4265 int dest_regno = REGNO (SET_DEST (set));
4267 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4268 ? HARD_REGNO_NREGS (dest_regno,
4269 GET_MODE (SET_DEST (set))) : 1);
4272 for (i = dest_regno; i < dest_endregno; i++)
4274 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
4275 || find_regno_note (insn, REG_DEAD, i))
4278 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
4279 ? gen_rtx_REG (reg_raw_mode[i], i)
4280 : SET_DEST (set)), NULL_RTX);
4281 delete_prior_computation (note, insn);
4285 for (note = REG_NOTES (insn); note; note = next)
4287 next = XEXP (note, 1);
4289 if (REG_NOTE_KIND (note) != REG_DEAD
4290 /* Verify that the REG_NOTE is legitimate. */
4291 || GET_CODE (XEXP (note, 0)) != REG)
4294 delete_prior_computation (note, insn);
4300 /* Delete insn INSN from the chain of insns and update label ref counts.
4301 May delete some following insns as a consequence; may even delete
4302 a label elsewhere and insns that follow it.
4304 Returns the first insn after INSN that was not deleted. */
4310 register rtx next = NEXT_INSN (insn);
4311 register rtx prev = PREV_INSN (insn);
4312 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
4313 register int dont_really_delete = 0;
4315 while (next && INSN_DELETED_P (next))
4316 next = NEXT_INSN (next);
4318 /* This insn is already deleted => return first following nondeleted. */
4319 if (INSN_DELETED_P (insn))
4323 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
4325 /* Don't delete user-declared labels. Convert them to special NOTEs
4327 if (was_code_label && LABEL_NAME (insn) != 0
4328 && optimize && ! dont_really_delete)
4330 PUT_CODE (insn, NOTE);
4331 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
4332 NOTE_SOURCE_FILE (insn) = 0;
4333 dont_really_delete = 1;
4336 /* Mark this insn as deleted. */
4337 INSN_DELETED_P (insn) = 1;
4339 /* If this is an unconditional jump, delete it from the jump chain. */
4340 if (simplejump_p (insn))
4341 delete_from_jump_chain (insn);
4343 /* If instruction is followed by a barrier,
4344 delete the barrier too. */
4346 if (next != 0 && GET_CODE (next) == BARRIER)
4348 INSN_DELETED_P (next) = 1;
4349 next = NEXT_INSN (next);
4352 /* Patch out INSN (and the barrier if any) */
4354 if (optimize && ! dont_really_delete)
4358 NEXT_INSN (prev) = next;
4359 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
4360 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
4361 XVECLEN (PATTERN (prev), 0) - 1)) = next;
4366 PREV_INSN (next) = prev;
4367 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
4368 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
4371 if (prev && NEXT_INSN (prev) == 0)
4372 set_last_insn (prev);
4375 /* If deleting a jump, decrement the count of the label,
4376 and delete the label if it is now unused. */
4378 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
4380 rtx lab = JUMP_LABEL (insn), lab_next;
4382 if (--LABEL_NUSES (lab) == 0)
4384 /* This can delete NEXT or PREV,
4385 either directly if NEXT is JUMP_LABEL (INSN),
4386 or indirectly through more levels of jumps. */
4389 /* I feel a little doubtful about this loop,
4390 but I see no clean and sure alternative way
4391 to find the first insn after INSN that is not now deleted.
4392 I hope this works. */
4393 while (next && INSN_DELETED_P (next))
4394 next = NEXT_INSN (next);
4397 else if ((lab_next = next_nonnote_insn (lab)) != NULL
4398 && GET_CODE (lab_next) == JUMP_INSN
4399 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
4400 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
4402 /* If we're deleting the tablejump, delete the dispatch table.
4403 We may not be able to kill the label immediately preceeding
4404 just yet, as it might be referenced in code leading up to
4406 delete_insn (lab_next);
4410 /* Likewise if we're deleting a dispatch table. */
4412 if (GET_CODE (insn) == JUMP_INSN
4413 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
4414 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
4416 rtx pat = PATTERN (insn);
4417 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4418 int len = XVECLEN (pat, diff_vec_p);
4420 for (i = 0; i < len; i++)
4421 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
4422 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
4423 while (next && INSN_DELETED_P (next))
4424 next = NEXT_INSN (next);
4428 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
4429 prev = PREV_INSN (prev);
4431 /* If INSN was a label and a dispatch table follows it,
4432 delete the dispatch table. The tablejump must have gone already.
4433 It isn't useful to fall through into a table. */
4436 && NEXT_INSN (insn) != 0
4437 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
4438 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
4439 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
4440 next = delete_insn (NEXT_INSN (insn));
4442 /* If INSN was a label, delete insns following it if now unreachable. */
4444 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
4446 register RTX_CODE code;
4448 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
4449 || code == NOTE || code == BARRIER
4450 || (code == CODE_LABEL && INSN_DELETED_P (next))))
4453 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
4454 next = NEXT_INSN (next);
4455 /* Keep going past other deleted labels to delete what follows. */
4456 else if (code == CODE_LABEL && INSN_DELETED_P (next))
4457 next = NEXT_INSN (next);
4459 /* Note: if this deletes a jump, it can cause more
4460 deletion of unreachable code, after a different label.
4461 As long as the value from this recursive call is correct,
4462 this invocation functions correctly. */
4463 next = delete_insn (next);
4470 /* Advance from INSN till reaching something not deleted
4471 then return that. May return INSN itself. */
4474 next_nondeleted_insn (insn)
4477 while (INSN_DELETED_P (insn))
4478 insn = NEXT_INSN (insn);
4482 /* Delete a range of insns from FROM to TO, inclusive.
4483 This is for the sake of peephole optimization, so assume
4484 that whatever these insns do will still be done by a new
4485 peephole insn that will replace them. */
4488 delete_for_peephole (from, to)
4489 register rtx from, to;
4491 register rtx insn = from;
4495 register rtx next = NEXT_INSN (insn);
4496 register rtx prev = PREV_INSN (insn);
4498 if (GET_CODE (insn) != NOTE)
4500 INSN_DELETED_P (insn) = 1;
4502 /* Patch this insn out of the chain. */
4503 /* We don't do this all at once, because we
4504 must preserve all NOTEs. */
4506 NEXT_INSN (prev) = next;
4509 PREV_INSN (next) = prev;
4517 /* Note that if TO is an unconditional jump
4518 we *do not* delete the BARRIER that follows,
4519 since the peephole that replaces this sequence
4520 is also an unconditional jump in that case. */
4523 /* We have determined that INSN is never reached, and are about to
4524 delete it. Print a warning if the user asked for one.
4526 To try to make this warning more useful, this should only be called
4527 once per basic block not reached, and it only warns when the basic
4528 block contains more than one line from the current function, and
4529 contains at least one operation. CSE and inlining can duplicate insns,
4530 so it's possible to get spurious warnings from this. */
4533 never_reached_warning (avoided_insn)
4537 rtx a_line_note = NULL;
4538 int two_avoided_lines = 0;
4539 int contains_insn = 0;
4541 if (! warn_notreached)
4544 /* Scan forwards, looking at LINE_NUMBER notes, until
4545 we hit a LABEL or we run out of insns. */
4547 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
4549 if (GET_CODE (insn) == CODE_LABEL)
4551 else if (GET_CODE (insn) == NOTE /* A line number note? */
4552 && NOTE_LINE_NUMBER (insn) >= 0)
4554 if (a_line_note == NULL)
4557 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
4558 != NOTE_LINE_NUMBER (insn));
4560 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
4563 if (two_avoided_lines && contains_insn)
4564 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
4565 NOTE_LINE_NUMBER (a_line_note),
4566 "will never be executed");
4569 /* Invert the condition of the jump JUMP, and make it jump
4570 to label NLABEL instead of where it jumps now. */
4573 invert_jump (jump, nlabel)
4576 /* We have to either invert the condition and change the label or
4577 do neither. Either operation could fail. We first try to invert
4578 the jump. If that succeeds, we try changing the label. If that fails,
4579 we invert the jump back to what it was. */
4581 if (! invert_exp (PATTERN (jump), jump))
4584 if (redirect_jump (jump, nlabel))
4586 if (flag_branch_probabilities)
4588 rtx note = find_reg_note (jump, REG_BR_PROB, 0);
4590 /* An inverted jump means that a probability taken becomes a
4591 probability not taken. Subtract the branch probability from the
4592 probability base to convert it back to a taken probability.
4593 (We don't flip the probability on a branch that's never taken. */
4594 if (note && XINT (XEXP (note, 0), 0) >= 0)
4595 XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
4601 if (! invert_exp (PATTERN (jump), jump))
4602 /* This should just be putting it back the way it was. */
4608 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4610 Return 1 if we can do so, 0 if we cannot find a way to do so that
4611 matches a pattern. */
4614 invert_exp (x, insn)
4618 register RTX_CODE code;
4620 register const char *fmt;
4622 code = GET_CODE (x);
4624 if (code == IF_THEN_ELSE)
4626 register rtx comp = XEXP (x, 0);
4629 /* We can do this in two ways: The preferable way, which can only
4630 be done if this is not an integer comparison, is to reverse
4631 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4632 of the IF_THEN_ELSE. If we can't do either, fail. */
4634 if (can_reverse_comparison_p (comp, insn)
4635 && validate_change (insn, &XEXP (x, 0),
4636 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
4637 GET_MODE (comp), XEXP (comp, 0),
4638 XEXP (comp, 1)), 0))
4642 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
4643 validate_change (insn, &XEXP (x, 2), tem, 1);
4644 return apply_change_group ();
4647 fmt = GET_RTX_FORMAT (code);
4648 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4651 if (! invert_exp (XEXP (x, i), insn))
4656 for (j = 0; j < XVECLEN (x, i); j++)
4657 if (!invert_exp (XVECEXP (x, i, j), insn))
4665 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4666 If the old jump target label is unused as a result,
4667 it and the code following it may be deleted.
4669 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4672 The return value will be 1 if the change was made, 0 if it wasn't (this
4673 can only occur for NLABEL == 0). */
4676 redirect_jump (jump, nlabel)
4679 register rtx olabel = JUMP_LABEL (jump);
4681 if (nlabel == olabel)
4684 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4687 /* If this is an unconditional branch, delete it from the jump_chain of
4688 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4689 have UID's in range and JUMP_CHAIN is valid). */
4690 if (jump_chain && (simplejump_p (jump)
4691 || GET_CODE (PATTERN (jump)) == RETURN))
4693 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4695 delete_from_jump_chain (jump);
4696 if (label_index < max_jump_chain
4697 && INSN_UID (jump) < max_jump_chain)
4699 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4700 jump_chain[label_index] = jump;
4704 JUMP_LABEL (jump) = nlabel;
4706 ++LABEL_NUSES (nlabel);
4708 if (olabel && --LABEL_NUSES (olabel) == 0)
4709 delete_insn (olabel);
4714 /* Delete the instruction JUMP from any jump chain it might be on. */
4717 delete_from_jump_chain (jump)
4721 rtx olabel = JUMP_LABEL (jump);
4723 /* Handle unconditional jumps. */
4724 if (jump_chain && olabel != 0
4725 && INSN_UID (olabel) < max_jump_chain
4726 && simplejump_p (jump))
4727 index = INSN_UID (olabel);
4728 /* Handle return insns. */
4729 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4733 if (jump_chain[index] == jump)
4734 jump_chain[index] = jump_chain[INSN_UID (jump)];
4739 for (insn = jump_chain[index];
4741 insn = jump_chain[INSN_UID (insn)])
4742 if (jump_chain[INSN_UID (insn)] == jump)
4744 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4750 /* If NLABEL is nonzero, throughout the rtx at LOC,
4751 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4752 zero, alter (RETURN) to (LABEL_REF NLABEL).
4754 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4755 validity with validate_change. Convert (set (pc) (label_ref olabel))
4758 Return 0 if we found a change we would like to make but it is invalid.
4759 Otherwise, return 1. */
4762 redirect_exp (loc, olabel, nlabel, insn)
4767 register rtx x = *loc;
4768 register RTX_CODE code = GET_CODE (x);
4770 register const char *fmt;
4772 if (code == LABEL_REF)
4774 if (XEXP (x, 0) == olabel)
4777 XEXP (x, 0) = nlabel;
4779 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4783 else if (code == RETURN && olabel == 0)
4785 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4786 if (loc == &PATTERN (insn))
4787 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4788 return validate_change (insn, loc, x, 0);
4791 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4792 && GET_CODE (SET_SRC (x)) == LABEL_REF
4793 && XEXP (SET_SRC (x), 0) == olabel)
4794 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4796 fmt = GET_RTX_FORMAT (code);
4797 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4800 if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
4805 for (j = 0; j < XVECLEN (x, i); j++)
4806 if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
4814 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4816 If the old jump target label (before the dispatch table) becomes unused,
4817 it and the dispatch table may be deleted. In that case, find the insn
4818 before the jump references that label and delete it and logical successors
4822 redirect_tablejump (jump, nlabel)
4825 register rtx olabel = JUMP_LABEL (jump);
4827 /* Add this jump to the jump_chain of NLABEL. */
4828 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4829 && INSN_UID (jump) < max_jump_chain)
4831 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4832 jump_chain[INSN_UID (nlabel)] = jump;
4835 PATTERN (jump) = gen_jump (nlabel);
4836 JUMP_LABEL (jump) = nlabel;
4837 ++LABEL_NUSES (nlabel);
4838 INSN_CODE (jump) = -1;
4840 if (--LABEL_NUSES (olabel) == 0)
4842 delete_labelref_insn (jump, olabel, 0);
4843 delete_insn (olabel);
4847 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4848 If we found one, delete it and then delete this insn if DELETE_THIS is
4849 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4852 delete_labelref_insn (insn, label, delete_this)
4859 if (GET_CODE (insn) != NOTE
4860 && reg_mentioned_p (label, PATTERN (insn)))
4871 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4872 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4886 /* Like rtx_equal_p except that it considers two REGs as equal
4887 if they renumber to the same value and considers two commutative
4888 operations to be the same if the order of the operands has been
4891 ??? Addition is not commutative on the PA due to the weird implicit
4892 space register selection rules for memory addresses. Therefore, we
4893 don't consider a + b == b + a.
4895 We could/should make this test a little tighter. Possibly only
4896 disabling it on the PA via some backend macro or only disabling this
4897 case when the PLUS is inside a MEM. */
4900 rtx_renumbered_equal_p (x, y)
4904 register RTX_CODE code = GET_CODE (x);
4905 register const char *fmt;
4910 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4911 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4912 && GET_CODE (SUBREG_REG (y)) == REG)))
4914 int reg_x = -1, reg_y = -1;
4915 int word_x = 0, word_y = 0;
4917 if (GET_MODE (x) != GET_MODE (y))
4920 /* If we haven't done any renumbering, don't
4921 make any assumptions. */
4922 if (reg_renumber == 0)
4923 return rtx_equal_p (x, y);
4927 reg_x = REGNO (SUBREG_REG (x));
4928 word_x = SUBREG_WORD (x);
4930 if (reg_renumber[reg_x] >= 0)
4932 reg_x = reg_renumber[reg_x] + word_x;
4940 if (reg_renumber[reg_x] >= 0)
4941 reg_x = reg_renumber[reg_x];
4944 if (GET_CODE (y) == SUBREG)
4946 reg_y = REGNO (SUBREG_REG (y));
4947 word_y = SUBREG_WORD (y);
4949 if (reg_renumber[reg_y] >= 0)
4951 reg_y = reg_renumber[reg_y];
4959 if (reg_renumber[reg_y] >= 0)
4960 reg_y = reg_renumber[reg_y];
4963 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4966 /* Now we have disposed of all the cases
4967 in which different rtx codes can match. */
4968 if (code != GET_CODE (y))
4980 return INTVAL (x) == INTVAL (y);
4983 /* We can't assume nonlocal labels have their following insns yet. */
4984 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4985 return XEXP (x, 0) == XEXP (y, 0);
4987 /* Two label-refs are equivalent if they point at labels
4988 in the same position in the instruction stream. */
4989 return (next_real_insn (XEXP (x, 0))
4990 == next_real_insn (XEXP (y, 0)));
4993 return XSTR (x, 0) == XSTR (y, 0);
4996 /* If we didn't match EQ equality above, they aren't the same. */
5003 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
5005 if (GET_MODE (x) != GET_MODE (y))
5008 /* For commutative operations, the RTX match if the operand match in any
5009 order. Also handle the simple binary and unary cases without a loop.
5011 ??? Don't consider PLUS a commutative operator; see comments above. */
5012 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5014 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5015 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
5016 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
5017 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
5018 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5019 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5020 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
5021 else if (GET_RTX_CLASS (code) == '1')
5022 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
5024 /* Compare the elements. If any pair of corresponding elements
5025 fail to match, return 0 for the whole things. */
5027 fmt = GET_RTX_FORMAT (code);
5028 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5034 if (XWINT (x, i) != XWINT (y, i))
5039 if (XINT (x, i) != XINT (y, i))
5044 if (strcmp (XSTR (x, i), XSTR (y, i)))
5049 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
5054 if (XEXP (x, i) != XEXP (y, i))
5061 if (XVECLEN (x, i) != XVECLEN (y, i))
5063 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5064 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
5075 /* If X is a hard register or equivalent to one or a subregister of one,
5076 return the hard register number. If X is a pseudo register that was not
5077 assigned a hard register, return the pseudo register number. Otherwise,
5078 return -1. Any rtx is valid for X. */
5084 if (GET_CODE (x) == REG)
5086 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
5087 return reg_renumber[REGNO (x)];
5090 if (GET_CODE (x) == SUBREG)
5092 int base = true_regnum (SUBREG_REG (x));
5093 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
5094 return SUBREG_WORD (x) + base;
5099 /* Optimize code of the form:
5101 for (x = a[i]; x; ...)
5103 for (x = a[i]; x; ...)
5107 Loop optimize will change the above code into
5111 { ...; if (! (x = ...)) break; }
5114 { ...; if (! (x = ...)) break; }
5117 In general, if the first test fails, the program can branch
5118 directly to `foo' and skip the second try which is doomed to fail.
5119 We run this after loop optimization and before flow analysis. */
5121 /* When comparing the insn patterns, we track the fact that different
5122 pseudo-register numbers may have been used in each computation.
5123 The following array stores an equivalence -- same_regs[I] == J means
5124 that pseudo register I was used in the first set of tests in a context
5125 where J was used in the second set. We also count the number of such
5126 pending equivalences. If nonzero, the expressions really aren't the
5129 static int *same_regs;
5131 static int num_same_regs;
5133 /* Track any registers modified between the target of the first jump and
5134 the second jump. They never compare equal. */
5136 static char *modified_regs;
5138 /* Record if memory was modified. */
5140 static int modified_mem;
5142 /* Called via note_stores on each insn between the target of the first
5143 branch and the second branch. It marks any changed registers. */
5146 mark_modified_reg (dest, x, data)
5148 rtx x ATTRIBUTE_UNUSED;
5149 void *data ATTRIBUTE_UNUSED;
5153 if (GET_CODE (dest) == SUBREG)
5154 dest = SUBREG_REG (dest);
5156 if (GET_CODE (dest) == MEM)
5159 if (GET_CODE (dest) != REG)
5162 regno = REGNO (dest);
5163 if (regno >= FIRST_PSEUDO_REGISTER)
5164 modified_regs[regno] = 1;
5166 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
5167 modified_regs[regno + i] = 1;
5170 /* F is the first insn in the chain of insns. */
5173 thread_jumps (f, max_reg, flag_before_loop)
5176 int flag_before_loop;
5178 /* Basic algorithm is to find a conditional branch,
5179 the label it may branch to, and the branch after
5180 that label. If the two branches test the same condition,
5181 walk back from both branch paths until the insn patterns
5182 differ, or code labels are hit. If we make it back to
5183 the target of the first branch, then we know that the first branch
5184 will either always succeed or always fail depending on the relative
5185 senses of the two branches. So adjust the first branch accordingly
5188 rtx label, b1, b2, t1, t2;
5189 enum rtx_code code1, code2;
5190 rtx b1op0, b1op1, b2op0, b2op1;
5195 /* Allocate register tables and quick-reset table. */
5196 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
5197 same_regs = (int *) xmalloc (max_reg * sizeof (int));
5198 all_reset = (int *) xmalloc (max_reg * sizeof (int));
5199 for (i = 0; i < max_reg; i++)
5206 for (b1 = f; b1; b1 = NEXT_INSN (b1))
5208 /* Get to a candidate branch insn. */
5209 if (GET_CODE (b1) != JUMP_INSN
5210 || ! condjump_p (b1) || simplejump_p (b1)
5211 || JUMP_LABEL (b1) == 0)
5214 bzero (modified_regs, max_reg * sizeof (char));
5217 bcopy ((char *) all_reset, (char *) same_regs,
5218 max_reg * sizeof (int));
5221 label = JUMP_LABEL (b1);
5223 /* Look for a branch after the target. Record any registers and
5224 memory modified between the target and the branch. Stop when we
5225 get to a label since we can't know what was changed there. */
5226 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
5228 if (GET_CODE (b2) == CODE_LABEL)
5231 else if (GET_CODE (b2) == JUMP_INSN)
5233 /* If this is an unconditional jump and is the only use of
5234 its target label, we can follow it. */
5235 if (simplejump_p (b2)
5236 && JUMP_LABEL (b2) != 0
5237 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
5239 b2 = JUMP_LABEL (b2);
5246 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
5249 if (GET_CODE (b2) == CALL_INSN)
5252 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5253 if (call_used_regs[i] && ! fixed_regs[i]
5254 && i != STACK_POINTER_REGNUM
5255 && i != FRAME_POINTER_REGNUM
5256 && i != HARD_FRAME_POINTER_REGNUM
5257 && i != ARG_POINTER_REGNUM)
5258 modified_regs[i] = 1;
5261 note_stores (PATTERN (b2), mark_modified_reg, NULL);
5264 /* Check the next candidate branch insn from the label
5267 || GET_CODE (b2) != JUMP_INSN
5269 || ! condjump_p (b2)
5270 || simplejump_p (b2))
5273 /* Get the comparison codes and operands, reversing the
5274 codes if appropriate. If we don't have comparison codes,
5275 we can't do anything. */
5276 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
5277 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
5278 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
5279 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
5280 code1 = reverse_condition (code1);
5282 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
5283 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
5284 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
5285 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
5286 code2 = reverse_condition (code2);
5288 /* If they test the same things and knowing that B1 branches
5289 tells us whether or not B2 branches, check if we
5290 can thread the branch. */
5291 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
5292 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
5293 && (comparison_dominates_p (code1, code2)
5294 || (comparison_dominates_p (code1, reverse_condition (code2))
5295 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
5299 t1 = prev_nonnote_insn (b1);
5300 t2 = prev_nonnote_insn (b2);
5302 while (t1 != 0 && t2 != 0)
5306 /* We have reached the target of the first branch.
5307 If there are no pending register equivalents,
5308 we know that this branch will either always
5309 succeed (if the senses of the two branches are
5310 the same) or always fail (if not). */
5313 if (num_same_regs != 0)
5316 if (comparison_dominates_p (code1, code2))
5317 new_label = JUMP_LABEL (b2);
5319 new_label = get_label_after (b2);
5321 if (JUMP_LABEL (b1) != new_label)
5323 rtx prev = PREV_INSN (new_label);
5325 if (flag_before_loop
5326 && GET_CODE (prev) == NOTE
5327 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
5329 /* Don't thread to the loop label. If a loop
5330 label is reused, loop optimization will
5331 be disabled for that loop. */
5332 new_label = gen_label_rtx ();
5333 emit_label_after (new_label, PREV_INSN (prev));
5335 changed |= redirect_jump (b1, new_label);
5340 /* If either of these is not a normal insn (it might be
5341 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5342 have already been skipped above.) Similarly, fail
5343 if the insns are different. */
5344 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
5345 || recog_memoized (t1) != recog_memoized (t2)
5346 || ! rtx_equal_for_thread_p (PATTERN (t1),
5350 t1 = prev_nonnote_insn (t1);
5351 t2 = prev_nonnote_insn (t2);
5358 free (modified_regs);
5363 /* This is like RTX_EQUAL_P except that it knows about our handling of
5364 possibly equivalent registers and knows to consider volatile and
5365 modified objects as not equal.
5367 YINSN is the insn containing Y. */
5370 rtx_equal_for_thread_p (x, y, yinsn)
5376 register enum rtx_code code;
5377 register const char *fmt;
5379 code = GET_CODE (x);
5380 /* Rtx's of different codes cannot be equal. */
5381 if (code != GET_CODE (y))
5384 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5385 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5387 if (GET_MODE (x) != GET_MODE (y))
5390 /* For floating-point, consider everything unequal. This is a bit
5391 pessimistic, but this pass would only rarely do anything for FP
5393 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
5394 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
5397 /* For commutative operations, the RTX match if the operand match in any
5398 order. Also handle the simple binary and unary cases without a loop. */
5399 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5400 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5401 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
5402 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
5403 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
5404 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5405 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5406 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
5407 else if (GET_RTX_CLASS (code) == '1')
5408 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5410 /* Handle special-cases first. */
5414 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
5417 /* If neither is user variable or hard register, check for possible
5419 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
5420 || REGNO (x) < FIRST_PSEUDO_REGISTER
5421 || REGNO (y) < FIRST_PSEUDO_REGISTER)
5424 if (same_regs[REGNO (x)] == -1)
5426 same_regs[REGNO (x)] = REGNO (y);
5429 /* If this is the first time we are seeing a register on the `Y'
5430 side, see if it is the last use. If not, we can't thread the
5431 jump, so mark it as not equivalent. */
5432 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
5438 return (same_regs[REGNO (x)] == REGNO (y));
5443 /* If memory modified or either volatile, not equivalent.
5444 Else, check address. */
5445 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5448 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5451 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5457 /* Cancel a pending `same_regs' if setting equivalenced registers.
5458 Then process source. */
5459 if (GET_CODE (SET_DEST (x)) == REG
5460 && GET_CODE (SET_DEST (y)) == REG)
5462 if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
5464 same_regs[REGNO (SET_DEST (x))] = -1;
5467 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
5471 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
5474 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
5477 return XEXP (x, 0) == XEXP (y, 0);
5480 return XSTR (x, 0) == XSTR (y, 0);
5489 fmt = GET_RTX_FORMAT (code);
5490 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5495 if (XWINT (x, i) != XWINT (y, i))
5501 if (XINT (x, i) != XINT (y, i))
5507 /* Two vectors must have the same length. */
5508 if (XVECLEN (x, i) != XVECLEN (y, i))
5511 /* And the corresponding elements must match. */
5512 for (j = 0; j < XVECLEN (x, i); j++)
5513 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
5514 XVECEXP (y, i, j), yinsn) == 0)
5519 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
5525 if (strcmp (XSTR (x, i), XSTR (y, i)))
5530 /* These are just backpointers, so they don't matter. */
5537 /* It is believed that rtx's at this level will never
5538 contain anything but integers and other rtx's,
5539 except for within LABEL_REFs and SYMBOL_REFs. */
5548 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5549 /* Return the insn that NEW can be safely inserted in front of starting at
5550 the jump insn INSN. Return 0 if it is not safe to do this jump
5551 optimization. Note that NEW must contain a single set. */
5554 find_insert_position (insn, new)
5561 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5562 if (GET_CODE (PATTERN (new)) != PARALLEL)
5565 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5566 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5567 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5574 /* There is a good chance that the previous insn PREV sets the thing
5575 being clobbered (often the CC in a hard reg). If PREV does not
5576 use what NEW sets, we can insert NEW before PREV. */
5578 prev = prev_active_insn (insn);
5579 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5580 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5581 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5583 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5587 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
5589 #endif /* !HAVE_cc0 */