1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-97, 1998 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. */
58 #include "hard-reg-set.h"
60 #include "insn-config.h"
61 #include "insn-flags.h"
68 /* ??? Eventually must record somehow the labels used by jumps
69 from nested functions. */
70 /* Pre-record the next or previous real insn for each label?
71 No, this pass is very fast anyway. */
72 /* Condense consecutive labels?
73 This would make life analysis faster, maybe. */
74 /* Optimize jump y; x: ... y: jumpif... x?
75 Don't know if it is worth bothering with. */
76 /* Optimize two cases of conditional jump to conditional jump?
77 This can never delete any instruction or make anything dead,
78 or even change what is live at any point.
79 So perhaps let combiner do it. */
81 /* Vector indexed by uid.
82 For each CODE_LABEL, index by its uid to get first unconditional jump
83 that jumps to the label.
84 For each JUMP_INSN, index by its uid to get the next unconditional jump
85 that jumps to the same label.
86 Element 0 is the start of a chain of all return insns.
87 (It is safe to use element 0 because insn uid 0 is not used. */
89 static rtx *jump_chain;
91 /* List of labels referred to from initializers.
92 These can never be deleted. */
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain;
99 /* Set nonzero by jump_optimize if control can fall through
100 to the end of the function. */
103 /* Indicates whether death notes are significant in cross jump analysis.
104 Normally they are not significant, because of A and B jump to C,
105 and R dies in A, it must die in B. But this might not be true after
106 stack register conversion, and we must compare death notes in that
109 static int cross_jump_death_matters = 0;
111 static int duplicate_loop_exit_test PROTO((rtx));
112 static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *));
113 static void do_cross_jump PROTO((rtx, rtx, rtx));
114 static int jump_back_p PROTO((rtx, rtx));
115 static int tension_vector_labels PROTO((rtx, int));
116 static void mark_jump_label PROTO((rtx, rtx, int));
117 static void delete_computation PROTO((rtx));
118 static void delete_from_jump_chain PROTO((rtx));
119 static int delete_labelref_insn PROTO((rtx, rtx, int));
120 static void mark_modified_reg PROTO((rtx, rtx));
121 static void redirect_tablejump PROTO((rtx, rtx));
123 static rtx find_insert_position PROTO((rtx, rtx));
126 /* Delete no-op jumps and optimize jumps to jumps
127 and jumps around jumps.
128 Delete unused labels and unreachable code.
130 If CROSS_JUMP is 1, detect matching code
131 before a jump and its destination and unify them.
132 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
134 If NOOP_MOVES is nonzero, delete no-op move insns.
136 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
137 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
139 If `optimize' is zero, don't change any code,
140 just determine whether control drops off the end of the function.
141 This case occurs when we have -W and not -O.
142 It works because `delete_insn' checks the value of `optimize'
143 and refrains from actually deleting when that is 0. */
146 jump_optimize (f, cross_jump, noop_moves, after_regscan)
152 register rtx insn, next, note;
159 cross_jump_death_matters = (cross_jump == 2);
161 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
162 notes whose labels don't occur in the insn any more. */
164 for (insn = f; insn; insn = NEXT_INSN (insn))
166 if (GET_CODE (insn) == CODE_LABEL)
167 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
168 else if (GET_CODE (insn) == JUMP_INSN)
169 JUMP_LABEL (insn) = 0;
170 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
171 for (note = REG_NOTES (insn); note; note = next)
173 next = XEXP (note, 1);
174 if (REG_NOTE_KIND (note) == REG_LABEL
175 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
176 remove_note (insn, note);
179 if (INSN_UID (insn) > max_uid)
180 max_uid = INSN_UID (insn);
185 /* Delete insns following barriers, up to next label. */
187 for (insn = f; insn;)
189 if (GET_CODE (insn) == BARRIER)
191 insn = NEXT_INSN (insn);
192 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
194 if (GET_CODE (insn) == NOTE
195 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
196 insn = NEXT_INSN (insn);
198 insn = delete_insn (insn);
200 /* INSN is now the code_label. */
203 insn = NEXT_INSN (insn);
206 /* Leave some extra room for labels and duplicate exit test insns
208 max_jump_chain = max_uid * 14 / 10;
209 jump_chain = (rtx *) alloca (max_jump_chain * sizeof (rtx));
210 bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx));
212 /* Mark the label each jump jumps to.
213 Combine consecutive labels, and count uses of labels.
215 For each label, make a chain (using `jump_chain')
216 of all the *unconditional* jumps that jump to it;
217 also make a chain of all returns. */
219 for (insn = f; insn; insn = NEXT_INSN (insn))
220 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
222 mark_jump_label (PATTERN (insn), insn, cross_jump);
223 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
225 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
227 jump_chain[INSN_UID (insn)]
228 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
229 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
231 if (GET_CODE (PATTERN (insn)) == RETURN)
233 jump_chain[INSN_UID (insn)] = jump_chain[0];
234 jump_chain[0] = insn;
239 /* Keep track of labels used from static data;
240 they cannot ever be deleted. */
242 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
243 LABEL_NUSES (XEXP (insn, 0))++;
245 check_exception_handler_labels ();
247 /* Keep track of labels used for marking handlers for exception
248 regions; they cannot usually be deleted. */
250 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
251 LABEL_NUSES (XEXP (insn, 0))++;
253 exception_optimize ();
255 /* Delete all labels already not referenced.
256 Also find the last insn. */
259 for (insn = f; insn; )
261 if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
262 insn = delete_insn (insn);
266 insn = NEXT_INSN (insn);
272 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
273 If so record that this function can drop off the end. */
279 /* One label can follow the end-note: the return label. */
280 && ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
281 /* Ordinary insns can follow it if returning a structure. */
282 || GET_CODE (insn) == INSN
283 /* If machine uses explicit RETURN insns, no epilogue,
284 then one of them follows the note. */
285 || (GET_CODE (insn) == JUMP_INSN
286 && GET_CODE (PATTERN (insn)) == RETURN)
287 /* A barrier can follow the return insn. */
288 || GET_CODE (insn) == BARRIER
289 /* Other kinds of notes can follow also. */
290 || (GET_CODE (insn) == NOTE
291 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
292 insn = PREV_INSN (insn);
295 /* Report if control can fall through at the end of the function. */
296 if (insn && GET_CODE (insn) == NOTE
297 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
298 && ! INSN_DELETED_P (insn))
301 /* Zero the "deleted" flag of all the "deleted" insns. */
302 for (insn = f; insn; insn = NEXT_INSN (insn))
303 INSN_DELETED_P (insn) = 0;
305 /* Show that the jump chain is not valid. */
313 /* If we fall through to the epilogue, see if we can insert a RETURN insn
314 in front of it. If the machine allows it at this point (we might be
315 after reload for a leaf routine), it will improve optimization for it
317 insn = get_last_insn ();
318 while (insn && GET_CODE (insn) == NOTE)
319 insn = PREV_INSN (insn);
321 if (insn && GET_CODE (insn) != BARRIER)
323 emit_jump_insn (gen_return ());
330 for (insn = f; insn; )
332 next = NEXT_INSN (insn);
334 if (GET_CODE (insn) == INSN)
336 register rtx body = PATTERN (insn);
338 /* Combine stack_adjusts with following push_insns. */
340 if (GET_CODE (body) == SET
341 && SET_DEST (body) == stack_pointer_rtx
342 && GET_CODE (SET_SRC (body)) == PLUS
343 && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
344 && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
345 && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
348 rtx stack_adjust_insn = insn;
349 int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
350 int total_pushed = 0;
353 /* Find all successive push insns. */
355 /* Don't convert more than three pushes;
356 that starts adding too many displaced addresses
357 and the whole thing starts becoming a losing
362 p = next_nonnote_insn (p);
363 if (p == 0 || GET_CODE (p) != INSN)
366 if (GET_CODE (pbody) != SET)
368 dest = SET_DEST (pbody);
369 /* Allow a no-op move between the adjust and the push. */
370 if (GET_CODE (dest) == REG
371 && GET_CODE (SET_SRC (pbody)) == REG
372 && REGNO (dest) == REGNO (SET_SRC (pbody)))
374 if (! (GET_CODE (dest) == MEM
375 && GET_CODE (XEXP (dest, 0)) == POST_INC
376 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
379 if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
380 > stack_adjust_amount)
382 total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
385 /* Discard the amount pushed from the stack adjust;
386 maybe eliminate it entirely. */
387 if (total_pushed >= stack_adjust_amount)
389 delete_computation (stack_adjust_insn);
390 total_pushed = stack_adjust_amount;
393 XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
394 = GEN_INT (stack_adjust_amount - total_pushed);
396 /* Change the appropriate push insns to ordinary stores. */
398 while (total_pushed > 0)
401 p = next_nonnote_insn (p);
402 if (GET_CODE (p) != INSN)
405 if (GET_CODE (pbody) != SET)
407 dest = SET_DEST (pbody);
408 /* Allow a no-op move between the adjust and the push. */
409 if (GET_CODE (dest) == REG
410 && GET_CODE (SET_SRC (pbody)) == REG
411 && REGNO (dest) == REGNO (SET_SRC (pbody)))
413 if (! (GET_CODE (dest) == MEM
414 && GET_CODE (XEXP (dest, 0)) == POST_INC
415 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
417 total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
418 /* If this push doesn't fully fit in the space
419 of the stack adjust that we deleted,
420 make another stack adjust here for what we
421 didn't use up. There should be peepholes
422 to recognize the resulting sequence of insns. */
423 if (total_pushed < 0)
425 emit_insn_before (gen_add2_insn (stack_pointer_rtx,
426 GEN_INT (- total_pushed)),
431 = plus_constant (stack_pointer_rtx, total_pushed);
436 /* Detect and delete no-op move instructions
437 resulting from not allocating a parameter in a register. */
439 if (GET_CODE (body) == SET
440 && (SET_DEST (body) == SET_SRC (body)
441 || (GET_CODE (SET_DEST (body)) == MEM
442 && GET_CODE (SET_SRC (body)) == MEM
443 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
444 && ! (GET_CODE (SET_DEST (body)) == MEM
445 && MEM_VOLATILE_P (SET_DEST (body)))
446 && ! (GET_CODE (SET_SRC (body)) == MEM
447 && MEM_VOLATILE_P (SET_SRC (body))))
448 delete_computation (insn);
450 /* Detect and ignore no-op move instructions
451 resulting from smart or fortuitous register allocation. */
453 else if (GET_CODE (body) == SET)
455 int sreg = true_regnum (SET_SRC (body));
456 int dreg = true_regnum (SET_DEST (body));
458 if (sreg == dreg && sreg >= 0)
460 else if (sreg >= 0 && dreg >= 0)
463 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
464 sreg, NULL_PTR, dreg,
465 GET_MODE (SET_SRC (body)));
468 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
470 /* DREG may have been the target of a REG_DEAD note in
471 the insn which makes INSN redundant. If so, reorg
472 would still think it is dead. So search for such a
473 note and delete it if we find it. */
474 if (! find_regno_note (insn, REG_UNUSED, dreg))
475 for (trial = prev_nonnote_insn (insn);
476 trial && GET_CODE (trial) != CODE_LABEL;
477 trial = prev_nonnote_insn (trial))
478 if (find_regno_note (trial, REG_DEAD, dreg))
480 remove_death (dreg, trial);
483 #ifdef PRESERVE_DEATH_INFO_REGNO_P
484 /* Deleting insn could lose a death-note for SREG
485 so don't do it if final needs accurate
487 if (PRESERVE_DEATH_INFO_REGNO_P (sreg)
488 && (trial = find_regno_note (insn, REG_DEAD, sreg)))
490 /* Change this into a USE so that we won't emit
491 code for it, but still can keep the note. */
493 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
494 INSN_CODE (insn) = -1;
495 /* Remove all reg notes but the REG_DEAD one. */
496 REG_NOTES (insn) = trial;
497 XEXP (trial, 1) = NULL_RTX;
504 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
505 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
507 GET_MODE (SET_DEST (body))))
509 /* This handles the case where we have two consecutive
510 assignments of the same constant to pseudos that didn't
511 get a hard reg. Each SET from the constant will be
512 converted into a SET of the spill register and an
513 output reload will be made following it. This produces
514 two loads of the same constant into the same spill
519 /* Look back for a death note for the first reg.
520 If there is one, it is no longer accurate. */
521 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
523 if ((GET_CODE (in_insn) == INSN
524 || GET_CODE (in_insn) == JUMP_INSN)
525 && find_regno_note (in_insn, REG_DEAD, dreg))
527 remove_death (dreg, in_insn);
530 in_insn = PREV_INSN (in_insn);
533 /* Delete the second load of the value. */
537 else if (GET_CODE (body) == PARALLEL)
539 /* If each part is a set between two identical registers or
540 a USE or CLOBBER, delete the insn. */
544 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
546 tem = XVECEXP (body, 0, i);
547 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
550 if (GET_CODE (tem) != SET
551 || (sreg = true_regnum (SET_SRC (tem))) < 0
552 || (dreg = true_regnum (SET_DEST (tem))) < 0
560 /* Also delete insns to store bit fields if they are no-ops. */
561 /* Not worth the hair to detect this in the big-endian case. */
562 else if (! BYTES_BIG_ENDIAN
563 && GET_CODE (body) == SET
564 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
565 && XEXP (SET_DEST (body), 2) == const0_rtx
566 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
567 && ! (GET_CODE (SET_SRC (body)) == MEM
568 && MEM_VOLATILE_P (SET_SRC (body))))
574 /* If we haven't yet gotten to reload and we have just run regscan,
575 delete any insn that sets a register that isn't used elsewhere.
576 This helps some of the optimizations below by having less insns
577 being jumped around. */
579 if (! reload_completed && after_regscan)
580 for (insn = f; insn; insn = next)
582 rtx set = single_set (insn);
584 next = NEXT_INSN (insn);
586 if (set && GET_CODE (SET_DEST (set)) == REG
587 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
588 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
589 /* We use regno_last_note_uid so as not to delete the setting
590 of a reg that's used in notes. A subsequent optimization
591 might arrange to use that reg for real. */
592 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
593 && ! side_effects_p (SET_SRC (set))
594 && ! find_reg_note (insn, REG_RETVAL, 0))
598 /* Now iterate optimizing jumps until nothing changes over one pass. */
600 old_max_reg = max_reg_num ();
605 for (insn = f; insn; insn = next)
608 rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
610 int this_is_simplejump, this_is_condjump, reversep = 0;
611 int this_is_condjump_in_parallel;
614 /* If NOT the first iteration, if this is the last jump pass
615 (just before final), do the special peephole optimizations.
616 Avoiding the first iteration gives ordinary jump opts
617 a chance to work before peephole opts. */
619 if (reload_completed && !first && !flag_no_peephole)
620 if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
624 /* That could have deleted some insns after INSN, so check now
625 what the following insn is. */
627 next = NEXT_INSN (insn);
629 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
630 jump. Try to optimize by duplicating the loop exit test if so.
631 This is only safe immediately after regscan, because it uses
632 the values of regno_first_uid and regno_last_uid. */
633 if (after_regscan && GET_CODE (insn) == NOTE
634 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
635 && (temp1 = next_nonnote_insn (insn)) != 0
636 && simplejump_p (temp1))
638 temp = PREV_INSN (insn);
639 if (duplicate_loop_exit_test (insn))
642 next = NEXT_INSN (temp);
647 if (GET_CODE (insn) != JUMP_INSN)
650 this_is_simplejump = simplejump_p (insn);
651 this_is_condjump = condjump_p (insn);
652 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
654 /* Tension the labels in dispatch tables. */
656 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
657 changed |= tension_vector_labels (PATTERN (insn), 0);
658 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
659 changed |= tension_vector_labels (PATTERN (insn), 1);
661 /* If a dispatch table always goes to the same place,
662 get rid of it and replace the insn that uses it. */
664 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
665 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
668 rtx pat = PATTERN (insn);
669 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
670 int len = XVECLEN (pat, diff_vec_p);
671 rtx dispatch = prev_real_insn (insn);
673 for (i = 0; i < len; i++)
674 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
675 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
679 && GET_CODE (dispatch) == JUMP_INSN
680 && JUMP_LABEL (dispatch) != 0
681 /* Don't mess with a casesi insn. */
682 && !(GET_CODE (PATTERN (dispatch)) == SET
683 && (GET_CODE (SET_SRC (PATTERN (dispatch)))
685 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
687 redirect_tablejump (dispatch,
688 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
693 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
695 /* If a jump references the end of the function, try to turn
696 it into a RETURN insn, possibly a conditional one. */
697 if (JUMP_LABEL (insn)
698 && (next_active_insn (JUMP_LABEL (insn)) == 0
699 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
701 changed |= redirect_jump (insn, NULL_RTX);
703 /* Detect jump to following insn. */
704 if (reallabelprev == insn && condjump_p (insn))
706 next = next_real_insn (JUMP_LABEL (insn));
712 /* If we have an unconditional jump preceded by a USE, try to put
713 the USE before the target and jump there. This simplifies many
714 of the optimizations below since we don't have to worry about
715 dealing with these USE insns. We only do this if the label
716 being branch to already has the identical USE or if code
717 never falls through to that label. */
719 if (this_is_simplejump
720 && (temp = prev_nonnote_insn (insn)) != 0
721 && GET_CODE (temp) == INSN && GET_CODE (PATTERN (temp)) == USE
722 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
723 && (GET_CODE (temp1) == BARRIER
724 || (GET_CODE (temp1) == INSN
725 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
726 /* Don't do this optimization if we have a loop containing only
727 the USE instruction, and the loop start label has a usage
728 count of 1. This is because we will redo this optimization
729 everytime through the outer loop, and jump opt will never
731 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
732 && temp2 == JUMP_LABEL (insn)
733 && LABEL_NUSES (temp2) == 1))
735 if (GET_CODE (temp1) == BARRIER)
737 emit_insn_after (PATTERN (temp), temp1);
738 temp1 = NEXT_INSN (temp1);
742 redirect_jump (insn, get_label_before (temp1));
743 reallabelprev = prev_real_insn (temp1);
747 /* Simplify if (...) x = a; else x = b; by converting it
748 to x = b; if (...) x = a;
749 if B is sufficiently simple, the test doesn't involve X,
750 and nothing in the test modifies B or X.
752 If we have small register classes, we also can't do this if X
755 If the "x = b;" insn has any REG_NOTES, we don't do this because
756 of the possibility that we are running after CSE and there is a
757 REG_EQUAL note that is only valid if the branch has already been
758 taken. If we move the insn with the REG_EQUAL note, we may
759 fold the comparison to always be false in a later CSE pass.
760 (We could also delete the REG_NOTES when moving the insn, but it
761 seems simpler to not move it.) An exception is that we can move
762 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
763 value is the same as "b".
765 INSN is the branch over the `else' part.
769 TEMP to the jump insn preceding "x = a;"
771 TEMP2 to the insn that sets "x = b;"
772 TEMP3 to the insn that sets "x = a;"
773 TEMP4 to the set of "x = b"; */
775 if (this_is_simplejump
776 && (temp3 = prev_active_insn (insn)) != 0
777 && GET_CODE (temp3) == INSN
778 && (temp4 = single_set (temp3)) != 0
779 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
780 && (! SMALL_REGISTER_CLASSES
781 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
782 && (temp2 = next_active_insn (insn)) != 0
783 && GET_CODE (temp2) == INSN
784 && (temp4 = single_set (temp2)) != 0
785 && rtx_equal_p (SET_DEST (temp4), temp1)
786 && ! side_effects_p (SET_SRC (temp4))
787 && ! may_trap_p (SET_SRC (temp4))
788 && (REG_NOTES (temp2) == 0
789 || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
790 || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
791 && XEXP (REG_NOTES (temp2), 1) == 0
792 && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
794 && (temp = prev_active_insn (temp3)) != 0
795 && condjump_p (temp) && ! simplejump_p (temp)
796 /* TEMP must skip over the "x = a;" insn */
797 && prev_real_insn (JUMP_LABEL (temp)) == insn
798 && no_labels_between_p (insn, JUMP_LABEL (temp))
799 /* There must be no other entries to the "x = b;" insn. */
800 && no_labels_between_p (JUMP_LABEL (temp), temp2)
801 /* INSN must either branch to the insn after TEMP2 or the insn
802 after TEMP2 must branch to the same place as INSN. */
803 && (reallabelprev == temp2
804 || ((temp5 = next_active_insn (temp2)) != 0
805 && simplejump_p (temp5)
806 && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
808 /* The test expression, X, may be a complicated test with
809 multiple branches. See if we can find all the uses of
810 the label that TEMP branches to without hitting a CALL_INSN
811 or a jump to somewhere else. */
812 rtx target = JUMP_LABEL (temp);
813 int nuses = LABEL_NUSES (target);
819 /* Set P to the first jump insn that goes around "x = a;". */
820 for (p = temp; nuses && p; p = prev_nonnote_insn (p))
822 if (GET_CODE (p) == JUMP_INSN)
824 if (condjump_p (p) && ! simplejump_p (p)
825 && JUMP_LABEL (p) == target)
834 else if (GET_CODE (p) == CALL_INSN)
839 /* We cannot insert anything between a set of cc and its use
840 so if P uses cc0, we must back up to the previous insn. */
841 q = prev_nonnote_insn (p);
842 if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
843 && sets_cc0_p (PATTERN (q)))
850 /* If we found all the uses and there was no data conflict, we
851 can move the assignment unless we can branch into the middle
854 && no_labels_between_p (p, insn)
855 && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
856 && ! reg_set_between_p (temp1, p, temp3)
857 && (GET_CODE (SET_SRC (temp4)) == CONST_INT
858 || ! modified_between_p (SET_SRC (temp4), p, temp2)))
860 emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
863 /* Set NEXT to an insn that we know won't go away. */
864 next = next_active_insn (insn);
866 /* Delete the jump around the set. Note that we must do
867 this before we redirect the test jumps so that it won't
868 delete the code immediately following the assignment
869 we moved (which might be a jump). */
873 /* We either have two consecutive labels or a jump to
874 a jump, so adjust all the JUMP_INSNs to branch to where
876 for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
877 if (GET_CODE (p) == JUMP_INSN)
878 redirect_jump (p, target);
885 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
886 to x = a; if (...) goto l; x = b;
887 if A is sufficiently simple, the test doesn't involve X,
888 and nothing in the test modifies A or X.
890 If we have small register classes, we also can't do this if X
893 If the "x = a;" insn has any REG_NOTES, we don't do this because
894 of the possibility that we are running after CSE and there is a
895 REG_EQUAL note that is only valid if the branch has already been
896 taken. If we move the insn with the REG_EQUAL note, we may
897 fold the comparison to always be false in a later CSE pass.
898 (We could also delete the REG_NOTES when moving the insn, but it
899 seems simpler to not move it.) An exception is that we can move
900 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
901 value is the same as "a".
907 TEMP to the jump insn preceding "x = a;"
909 TEMP2 to the insn that sets "x = b;"
910 TEMP3 to the insn that sets "x = a;"
911 TEMP4 to the set of "x = a"; */
913 if (this_is_simplejump
914 && (temp2 = next_active_insn (insn)) != 0
915 && GET_CODE (temp2) == INSN
916 && (temp4 = single_set (temp2)) != 0
917 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
918 && (! SMALL_REGISTER_CLASSES
919 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
920 && (temp3 = prev_active_insn (insn)) != 0
921 && GET_CODE (temp3) == INSN
922 && (temp4 = single_set (temp3)) != 0
923 && rtx_equal_p (SET_DEST (temp4), temp1)
924 && ! side_effects_p (SET_SRC (temp4))
925 && ! may_trap_p (SET_SRC (temp4))
926 && (REG_NOTES (temp3) == 0
927 || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
928 || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
929 && XEXP (REG_NOTES (temp3), 1) == 0
930 && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
932 && (temp = prev_active_insn (temp3)) != 0
933 && condjump_p (temp) && ! simplejump_p (temp)
934 /* TEMP must skip over the "x = a;" insn */
935 && prev_real_insn (JUMP_LABEL (temp)) == insn
936 && no_labels_between_p (temp, insn))
938 rtx prev_label = JUMP_LABEL (temp);
939 rtx insert_after = prev_nonnote_insn (temp);
942 /* We cannot insert anything between a set of cc and its use. */
943 if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
944 && sets_cc0_p (PATTERN (insert_after)))
945 insert_after = prev_nonnote_insn (insert_after);
947 ++LABEL_NUSES (prev_label);
950 && no_labels_between_p (insert_after, temp)
951 && ! reg_referenced_between_p (temp1, insert_after, temp3)
952 && ! reg_referenced_between_p (temp1, temp3,
954 && ! reg_set_between_p (temp1, insert_after, temp)
955 && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
956 && invert_jump (temp, JUMP_LABEL (insn)))
958 emit_insn_after_with_line_notes (PATTERN (temp3),
959 insert_after, temp3);
962 /* Set NEXT to an insn that we know won't go away. */
966 if (prev_label && --LABEL_NUSES (prev_label) == 0)
967 delete_insn (prev_label);
973 /* If we have if (...) x = exp; and branches are expensive,
974 EXP is a single insn, does not have any side effects, cannot
975 trap, and is not too costly, convert this to
976 t = exp; if (...) x = t;
978 Don't do this when we have CC0 because it is unlikely to help
979 and we'd need to worry about where to place the new insn and
980 the potential for conflicts. We also can't do this when we have
981 notes on the insn for the same reason as above.
985 TEMP to the "x = exp;" insn.
986 TEMP1 to the single set in the "x = exp;" insn.
989 if (! reload_completed
990 && this_is_condjump && ! this_is_simplejump
992 && (temp = next_nonnote_insn (insn)) != 0
993 && GET_CODE (temp) == INSN
994 && REG_NOTES (temp) == 0
995 && (reallabelprev == temp
996 || ((temp2 = next_active_insn (temp)) != 0
997 && simplejump_p (temp2)
998 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
999 && (temp1 = single_set (temp)) != 0
1000 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
1001 && (! SMALL_REGISTER_CLASSES
1002 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
1003 && GET_CODE (SET_SRC (temp1)) != REG
1004 && GET_CODE (SET_SRC (temp1)) != SUBREG
1005 && GET_CODE (SET_SRC (temp1)) != CONST_INT
1006 && ! side_effects_p (SET_SRC (temp1))
1007 && ! may_trap_p (SET_SRC (temp1))
1008 && rtx_cost (SET_SRC (temp1), SET) < 10)
1010 rtx new = gen_reg_rtx (GET_MODE (temp2));
1012 if ((temp3 = find_insert_position (insn, temp))
1013 && validate_change (temp, &SET_DEST (temp1), new, 0))
1015 next = emit_insn_after (gen_move_insn (temp2, new), insn);
1016 emit_insn_after_with_line_notes (PATTERN (temp),
1017 PREV_INSN (temp3), temp);
1019 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
1023 reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
1024 old_max_reg = max_reg_num ();
1029 /* Similarly, if it takes two insns to compute EXP but they
1030 have the same destination. Here TEMP3 will be the second
1031 insn and TEMP4 the SET from that insn. */
1033 if (! reload_completed
1034 && this_is_condjump && ! this_is_simplejump
1036 && (temp = next_nonnote_insn (insn)) != 0
1037 && GET_CODE (temp) == INSN
1038 && REG_NOTES (temp) == 0
1039 && (temp3 = next_nonnote_insn (temp)) != 0
1040 && GET_CODE (temp3) == INSN
1041 && REG_NOTES (temp3) == 0
1042 && (reallabelprev == temp3
1043 || ((temp2 = next_active_insn (temp3)) != 0
1044 && simplejump_p (temp2)
1045 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
1046 && (temp1 = single_set (temp)) != 0
1047 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
1048 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
1049 && (! SMALL_REGISTER_CLASSES
1050 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
1051 && ! side_effects_p (SET_SRC (temp1))
1052 && ! may_trap_p (SET_SRC (temp1))
1053 && rtx_cost (SET_SRC (temp1), SET) < 10
1054 && (temp4 = single_set (temp3)) != 0
1055 && rtx_equal_p (SET_DEST (temp4), temp2)
1056 && ! side_effects_p (SET_SRC (temp4))
1057 && ! may_trap_p (SET_SRC (temp4))
1058 && rtx_cost (SET_SRC (temp4), SET) < 10)
1060 rtx new = gen_reg_rtx (GET_MODE (temp2));
1062 if ((temp5 = find_insert_position (insn, temp))
1063 && (temp6 = find_insert_position (insn, temp3))
1064 && validate_change (temp, &SET_DEST (temp1), new, 0))
1066 /* Use the earliest of temp5 and temp6. */
1069 next = emit_insn_after (gen_move_insn (temp2, new), insn);
1070 emit_insn_after_with_line_notes (PATTERN (temp),
1071 PREV_INSN (temp6), temp);
1072 emit_insn_after_with_line_notes
1073 (replace_rtx (PATTERN (temp3), temp2, new),
1074 PREV_INSN (temp6), temp3);
1076 delete_insn (temp3);
1077 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
1081 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
1082 old_max_reg = max_reg_num ();
1087 /* Finally, handle the case where two insns are used to
1088 compute EXP but a temporary register is used. Here we must
1089 ensure that the temporary register is not used anywhere else. */
1091 if (! reload_completed
1093 && this_is_condjump && ! this_is_simplejump
1095 && (temp = next_nonnote_insn (insn)) != 0
1096 && GET_CODE (temp) == INSN
1097 && REG_NOTES (temp) == 0
1098 && (temp3 = next_nonnote_insn (temp)) != 0
1099 && GET_CODE (temp3) == INSN
1100 && REG_NOTES (temp3) == 0
1101 && (reallabelprev == temp3
1102 || ((temp2 = next_active_insn (temp3)) != 0
1103 && simplejump_p (temp2)
1104 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
1105 && (temp1 = single_set (temp)) != 0
1106 && (temp5 = SET_DEST (temp1),
1107 (GET_CODE (temp5) == REG
1108 || (GET_CODE (temp5) == SUBREG
1109 && (temp5 = SUBREG_REG (temp5),
1110 GET_CODE (temp5) == REG))))
1111 && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
1112 && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
1113 && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
1114 && ! side_effects_p (SET_SRC (temp1))
1115 && ! may_trap_p (SET_SRC (temp1))
1116 && rtx_cost (SET_SRC (temp1), SET) < 10
1117 && (temp4 = single_set (temp3)) != 0
1118 && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
1119 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
1120 && (! SMALL_REGISTER_CLASSES
1121 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
1122 && rtx_equal_p (SET_DEST (temp4), temp2)
1123 && ! side_effects_p (SET_SRC (temp4))
1124 && ! may_trap_p (SET_SRC (temp4))
1125 && rtx_cost (SET_SRC (temp4), SET) < 10)
1127 rtx new = gen_reg_rtx (GET_MODE (temp2));
1129 if ((temp5 = find_insert_position (insn, temp))
1130 && (temp6 = find_insert_position (insn, temp3))
1131 && validate_change (temp3, &SET_DEST (temp4), new, 0))
1133 /* Use the earliest of temp5 and temp6. */
1136 next = emit_insn_after (gen_move_insn (temp2, new), insn);
1137 emit_insn_after_with_line_notes (PATTERN (temp),
1138 PREV_INSN (temp6), temp);
1139 emit_insn_after_with_line_notes (PATTERN (temp3),
1140 PREV_INSN (temp6), temp3);
1142 delete_insn (temp3);
1143 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
1147 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
1148 old_max_reg = max_reg_num ();
1152 #endif /* HAVE_cc0 */
1154 /* Try to use a conditional move (if the target has them), or a
1155 store-flag insn. The general case is:
1157 1) x = a; if (...) x = b; and
1160 If the jump would be faster, the machine should not have defined
1161 the movcc or scc insns!. These cases are often made by the
1162 previous optimization.
1164 The second case is treated as x = x; if (...) x = b;.
1166 INSN here is the jump around the store. We set:
1168 TEMP to the "x = b;" insn.
1171 TEMP3 to A (X in the second case).
1172 TEMP4 to the condition being tested.
1173 TEMP5 to the earliest insn used to find the condition. */
1175 if (/* We can't do this after reload has completed. */
1177 && this_is_condjump && ! this_is_simplejump
1178 /* Set TEMP to the "x = b;" insn. */
1179 && (temp = next_nonnote_insn (insn)) != 0
1180 && GET_CODE (temp) == INSN
1181 && GET_CODE (PATTERN (temp)) == SET
1182 && GET_CODE (temp1 = SET_DEST (PATTERN (temp))) == REG
1183 && (! SMALL_REGISTER_CLASSES
1184 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
1185 && ! side_effects_p (temp2 = SET_SRC (PATTERN (temp)))
1186 && ! may_trap_p (temp2)
1187 /* Allow either form, but prefer the former if both apply.
1188 There is no point in using the old value of TEMP1 if
1189 it is a register, since cse will alias them. It can
1190 lose if the old value were a hard register since CSE
1191 won't replace hard registers. Avoid using TEMP3 if
1192 small register classes and it is a hard register. */
1193 && (((temp3 = reg_set_last (temp1, insn)) != 0
1194 && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
1195 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
1196 /* Make the latter case look like x = x; if (...) x = b; */
1197 || (temp3 = temp1, 1))
1198 /* INSN must either branch to the insn after TEMP or the insn
1199 after TEMP must branch to the same place as INSN. */
1200 && (reallabelprev == temp
1201 || ((temp4 = next_active_insn (temp)) != 0
1202 && simplejump_p (temp4)
1203 && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
1204 && (temp4 = get_condition (insn, &temp5)) != 0
1205 /* We must be comparing objects whose modes imply the size.
1206 We could handle BLKmode if (1) emit_store_flag could
1207 and (2) we could find the size reliably. */
1208 && GET_MODE (XEXP (temp4, 0)) != BLKmode
1209 /* Even if branches are cheap, the store_flag optimization
1210 can win when the operation to be performed can be
1211 expressed directly. */
1213 /* If the previous insn sets CC0 and something else, we can't
1214 do this since we are going to delete that insn. */
1216 && ! ((temp6 = prev_nonnote_insn (insn)) != 0
1217 && GET_CODE (temp6) == INSN
1218 && (sets_cc0_p (PATTERN (temp6)) == -1
1219 || (sets_cc0_p (PATTERN (temp6)) == 1
1220 && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
1224 #ifdef HAVE_conditional_move
1225 /* First try a conditional move. */
1227 enum rtx_code code = GET_CODE (temp4);
1229 rtx cond0, cond1, aval, bval;
1232 /* Copy the compared variables into cond0 and cond1, so that
1233 any side effects performed in or after the old comparison,
1234 will not affect our compare which will come later. */
1235 /* ??? Is it possible to just use the comparison in the jump
1236 insn? After all, we're going to delete it. We'd have
1237 to modify emit_conditional_move to take a comparison rtx
1238 instead or write a new function. */
1239 cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
1240 /* We want the target to be able to simplify comparisons with
1241 zero (and maybe other constants as well), so don't create
1242 pseudos for them. There's no need to either. */
1243 if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
1244 || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
1245 cond1 = XEXP (temp4, 1);
1247 cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
1253 target = emit_conditional_move (var, code,
1254 cond0, cond1, VOIDmode,
1255 aval, bval, GET_MODE (var),
1256 (code == LTU || code == GEU
1257 || code == LEU || code == GTU));
1263 /* Save the conditional move sequence but don't emit it
1264 yet. On some machines, like the alpha, it is possible
1265 that temp5 == insn, so next generate the sequence that
1266 saves the compared values and then emit both
1267 sequences ensuring seq1 occurs before seq2. */
1268 seq2 = get_insns ();
1271 /* Now that we can't fail, generate the copy insns that
1272 preserve the compared values. */
1274 emit_move_insn (cond0, XEXP (temp4, 0));
1275 if (cond1 != XEXP (temp4, 1))
1276 emit_move_insn (cond1, XEXP (temp4, 1));
1277 seq1 = get_insns ();
1280 emit_insns_before (seq1, temp5);
1281 /* Insert conditional move after insn, to be sure that
1282 the jump and a possible compare won't be separated */
1283 last = emit_insns_after (seq2, insn);
1285 /* ??? We can also delete the insn that sets X to A.
1286 Flow will do it too though. */
1288 next = NEXT_INSN (insn);
1293 reg_scan_update (seq1, NEXT_INSN (last), old_max_reg);
1294 old_max_reg = max_reg_num ();
1305 /* That didn't work, try a store-flag insn.
1307 We further divide the cases into:
1309 1) x = a; if (...) x = b; and either A or B is zero,
1310 2) if (...) x = 0; and jumps are expensive,
1311 3) x = a; if (...) x = b; and A and B are constants where all
1312 the set bits in A are also set in B and jumps are expensive,
1313 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1315 5) if (...) x = b; if jumps are even more expensive. */
1317 if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
1318 && ((GET_CODE (temp3) == CONST_INT)
1319 /* Make the latter case look like
1320 x = x; if (...) x = 0; */
1323 && temp2 == const0_rtx)
1324 || BRANCH_COST >= 3)))
1325 /* If B is zero, OK; if A is zero, can only do (1) if we
1326 can reverse the condition. See if (3) applies possibly
1327 by reversing the condition. Prefer reversing to (4) when
1328 branches are very expensive. */
1329 && (((BRANCH_COST >= 2
1330 || STORE_FLAG_VALUE == -1
1331 || (STORE_FLAG_VALUE == 1
1332 /* Check that the mask is a power of two,
1333 so that it can probably be generated
1335 && GET_CODE (temp3) == CONST_INT
1336 && exact_log2 (INTVAL (temp3)) >= 0))
1337 && (reversep = 0, temp2 == const0_rtx))
1338 || ((BRANCH_COST >= 2
1339 || STORE_FLAG_VALUE == -1
1340 || (STORE_FLAG_VALUE == 1
1341 && GET_CODE (temp2) == CONST_INT
1342 && exact_log2 (INTVAL (temp2)) >= 0))
1343 && temp3 == const0_rtx
1344 && (reversep = can_reverse_comparison_p (temp4, insn)))
1345 || (BRANCH_COST >= 2
1346 && GET_CODE (temp2) == CONST_INT
1347 && GET_CODE (temp3) == CONST_INT
1348 && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
1349 || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
1350 && (reversep = can_reverse_comparison_p (temp4,
1352 || BRANCH_COST >= 3)
1355 enum rtx_code code = GET_CODE (temp4);
1356 rtx uval, cval, var = temp1;
1360 /* If necessary, reverse the condition. */
1362 code = reverse_condition (code), uval = temp2, cval = temp3;
1364 uval = temp3, cval = temp2;
1366 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1367 is the constant 1, it is best to just compute the result
1368 directly. If UVAL is constant and STORE_FLAG_VALUE
1369 includes all of its bits, it is best to compute the flag
1370 value unnormalized and `and' it with UVAL. Otherwise,
1371 normalize to -1 and `and' with UVAL. */
1372 normalizep = (cval != const0_rtx ? -1
1373 : (uval == const1_rtx ? 1
1374 : (GET_CODE (uval) == CONST_INT
1375 && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
1378 /* We will be putting the store-flag insn immediately in
1379 front of the comparison that was originally being done,
1380 so we know all the variables in TEMP4 will be valid.
1381 However, this might be in front of the assignment of
1382 A to VAR. If it is, it would clobber the store-flag
1383 we will be emitting.
1385 Therefore, emit into a temporary which will be copied to
1386 VAR immediately after TEMP. */
1389 target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
1390 XEXP (temp4, 0), XEXP (temp4, 1),
1392 (code == LTU || code == LEU
1393 || code == GEU || code == GTU),
1403 /* Put the store-flag insns in front of the first insn
1404 used to compute the condition to ensure that we
1405 use the same values of them as the current
1406 comparison. However, the remainder of the insns we
1407 generate will be placed directly in front of the
1408 jump insn, in case any of the pseudos we use
1409 are modified earlier. */
1411 emit_insns_before (seq, temp5);
1415 /* Both CVAL and UVAL are non-zero. */
1416 if (cval != const0_rtx && uval != const0_rtx)
1420 tem1 = expand_and (uval, target, NULL_RTX);
1421 if (GET_CODE (cval) == CONST_INT
1422 && GET_CODE (uval) == CONST_INT
1423 && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
1427 tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
1428 target, NULL_RTX, 0);
1429 tem2 = expand_and (cval, tem2,
1430 (GET_CODE (tem2) == REG
1434 /* If we usually make new pseudos, do so here. This
1435 turns out to help machines that have conditional
1437 /* ??? Conditional moves have already been handled.
1438 This may be obsolete. */
1440 if (flag_expensive_optimizations)
1443 target = expand_binop (GET_MODE (var), ior_optab,
1447 else if (normalizep != 1)
1449 /* We know that either CVAL or UVAL is zero. If
1450 UVAL is zero, negate TARGET and `and' with CVAL.
1451 Otherwise, `and' with UVAL. */
1452 if (uval == const0_rtx)
1454 target = expand_unop (GET_MODE (var), one_cmpl_optab,
1455 target, NULL_RTX, 0);
1459 target = expand_and (uval, target,
1460 (GET_CODE (target) == REG
1461 && ! preserve_subexpressions_p ()
1462 ? target : NULL_RTX));
1465 emit_move_insn (var, target);
1469 /* If INSN uses CC0, we must not separate it from the
1470 insn that sets cc0. */
1471 if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
1472 before = prev_nonnote_insn (before);
1474 emit_insns_before (seq, before);
1477 next = NEXT_INSN (insn);
1482 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1483 old_max_reg = max_reg_num ();
1494 /* If branches are expensive, convert
1495 if (foo) bar++; to bar += (foo != 0);
1496 and similarly for "bar--;"
1498 INSN is the conditional branch around the arithmetic. We set:
1500 TEMP is the arithmetic insn.
1501 TEMP1 is the SET doing the arithmetic.
1502 TEMP2 is the operand being incremented or decremented.
1503 TEMP3 to the condition being tested.
1504 TEMP4 to the earliest insn used to find the condition. */
1506 if ((BRANCH_COST >= 2
1514 && ! reload_completed
1515 && this_is_condjump && ! this_is_simplejump
1516 && (temp = next_nonnote_insn (insn)) != 0
1517 && (temp1 = single_set (temp)) != 0
1518 && (temp2 = SET_DEST (temp1),
1519 GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
1520 && GET_CODE (SET_SRC (temp1)) == PLUS
1521 && (XEXP (SET_SRC (temp1), 1) == const1_rtx
1522 || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
1523 && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
1524 && ! side_effects_p (temp2)
1525 && ! may_trap_p (temp2)
1526 /* INSN must either branch to the insn after TEMP or the insn
1527 after TEMP must branch to the same place as INSN. */
1528 && (reallabelprev == temp
1529 || ((temp3 = next_active_insn (temp)) != 0
1530 && simplejump_p (temp3)
1531 && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
1532 && (temp3 = get_condition (insn, &temp4)) != 0
1533 /* We must be comparing objects whose modes imply the size.
1534 We could handle BLKmode if (1) emit_store_flag could
1535 and (2) we could find the size reliably. */
1536 && GET_MODE (XEXP (temp3, 0)) != BLKmode
1537 && can_reverse_comparison_p (temp3, insn))
1539 rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
1540 enum rtx_code code = reverse_condition (GET_CODE (temp3));
1544 /* It must be the case that TEMP2 is not modified in the range
1545 [TEMP4, INSN). The one exception we make is if the insn
1546 before INSN sets TEMP2 to something which is also unchanged
1547 in that range. In that case, we can move the initialization
1548 into our sequence. */
1550 if ((temp5 = prev_active_insn (insn)) != 0
1551 && no_labels_between_p (temp5, insn)
1552 && GET_CODE (temp5) == INSN
1553 && (temp6 = single_set (temp5)) != 0
1554 && rtx_equal_p (temp2, SET_DEST (temp6))
1555 && (CONSTANT_P (SET_SRC (temp6))
1556 || GET_CODE (SET_SRC (temp6)) == REG
1557 || GET_CODE (SET_SRC (temp6)) == SUBREG))
1559 emit_insn (PATTERN (temp5));
1561 init = SET_SRC (temp6);
1564 if (CONSTANT_P (init)
1565 || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
1566 target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
1567 XEXP (temp3, 0), XEXP (temp3, 1),
1569 (code == LTU || code == LEU
1570 || code == GTU || code == GEU), 1);
1572 /* If we can do the store-flag, do the addition or
1576 target = expand_binop (GET_MODE (temp2),
1577 (XEXP (SET_SRC (temp1), 1) == const1_rtx
1578 ? add_optab : sub_optab),
1579 temp2, target, temp2, 0, OPTAB_WIDEN);
1583 /* Put the result back in temp2 in case it isn't already.
1584 Then replace the jump, possible a CC0-setting insn in
1585 front of the jump, and TEMP, with the sequence we have
1588 if (target != temp2)
1589 emit_move_insn (temp2, target);
1594 emit_insns_before (seq, temp4);
1598 delete_insn (init_insn);
1600 next = NEXT_INSN (insn);
1602 delete_insn (prev_nonnote_insn (insn));
1608 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1609 old_max_reg = max_reg_num ();
1619 /* Simplify if (...) x = 1; else {...} if (x) ...
1620 We recognize this case scanning backwards as well.
1622 TEMP is the assignment to x;
1623 TEMP1 is the label at the head of the second if. */
1624 /* ?? This should call get_condition to find the values being
1625 compared, instead of looking for a COMPARE insn when HAVE_cc0
1626 is not defined. This would allow it to work on the m88k. */
1627 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1628 is not defined and the condition is tested by a separate compare
1629 insn. This is because the code below assumes that the result
1630 of the compare dies in the following branch.
1632 Not only that, but there might be other insns between the
1633 compare and branch whose results are live. Those insns need
1636 A way to fix this is to move the insns at JUMP_LABEL (insn)
1637 to before INSN. If we are running before flow, they will
1638 be deleted if they aren't needed. But this doesn't work
1641 This is really a special-case of jump threading, anyway. The
1642 right thing to do is to replace this and jump threading with
1643 much simpler code in cse.
1645 This code has been turned off in the non-cc0 case in the
1649 else if (this_is_simplejump
1650 /* Safe to skip USE and CLOBBER insns here
1651 since they will not be deleted. */
1652 && (temp = prev_active_insn (insn))
1653 && no_labels_between_p (temp, insn)
1654 && GET_CODE (temp) == INSN
1655 && GET_CODE (PATTERN (temp)) == SET
1656 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1657 && CONSTANT_P (SET_SRC (PATTERN (temp)))
1658 && (temp1 = next_active_insn (JUMP_LABEL (insn)))
1659 /* If we find that the next value tested is `x'
1660 (TEMP1 is the insn where this happens), win. */
1661 && GET_CODE (temp1) == INSN
1662 && GET_CODE (PATTERN (temp1)) == SET
1664 /* Does temp1 `tst' the value of x? */
1665 && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
1666 && SET_DEST (PATTERN (temp1)) == cc0_rtx
1667 && (temp1 = next_nonnote_insn (temp1))
1669 /* Does temp1 compare the value of x against zero? */
1670 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1671 && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
1672 && (XEXP (SET_SRC (PATTERN (temp1)), 0)
1673 == SET_DEST (PATTERN (temp)))
1674 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1675 && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1677 && condjump_p (temp1))
1679 /* Get the if_then_else from the condjump. */
1680 rtx choice = SET_SRC (PATTERN (temp1));
1681 if (GET_CODE (choice) == IF_THEN_ELSE)
1683 enum rtx_code code = GET_CODE (XEXP (choice, 0));
1684 rtx val = SET_SRC (PATTERN (temp));
1686 = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
1690 if (cond == const_true_rtx)
1691 ultimate = XEXP (choice, 1);
1692 else if (cond == const0_rtx)
1693 ultimate = XEXP (choice, 2);
1697 if (ultimate == pc_rtx)
1698 ultimate = get_label_after (temp1);
1699 else if (ultimate && GET_CODE (ultimate) != RETURN)
1700 ultimate = XEXP (ultimate, 0);
1702 if (ultimate && JUMP_LABEL(insn) != ultimate)
1703 changed |= redirect_jump (insn, ultimate);
1709 /* @@ This needs a bit of work before it will be right.
1711 Any type of comparison can be accepted for the first and
1712 second compare. When rewriting the first jump, we must
1713 compute the what conditions can reach label3, and use the
1714 appropriate code. We can not simply reverse/swap the code
1715 of the first jump. In some cases, the second jump must be
1719 < == converts to > ==
1720 < != converts to == >
1723 If the code is written to only accept an '==' test for the second
1724 compare, then all that needs to be done is to swap the condition
1725 of the first branch.
1727 It is questionable whether we want this optimization anyways,
1728 since if the user wrote code like this because he/she knew that
1729 the jump to label1 is taken most of the time, then rewriting
1730 this gives slower code. */
1731 /* @@ This should call get_condition to find the values being
1732 compared, instead of looking for a COMPARE insn when HAVE_cc0
1733 is not defined. This would allow it to work on the m88k. */
1734 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1735 is not defined and the condition is tested by a separate compare
1736 insn. This is because the code below assumes that the result
1737 of the compare dies in the following branch. */
1739 /* Simplify test a ~= b
1753 where ~= is an inequality, e.g. >, and ~~= is the swapped
1756 We recognize this case scanning backwards.
1758 TEMP is the conditional jump to `label2';
1759 TEMP1 is the test for `a == b';
1760 TEMP2 is the conditional jump to `label1';
1761 TEMP3 is the test for `a ~= b'. */
1762 else if (this_is_simplejump
1763 && (temp = prev_active_insn (insn))
1764 && no_labels_between_p (temp, insn)
1765 && condjump_p (temp)
1766 && (temp1 = prev_active_insn (temp))
1767 && no_labels_between_p (temp1, temp)
1768 && GET_CODE (temp1) == INSN
1769 && GET_CODE (PATTERN (temp1)) == SET
1771 && sets_cc0_p (PATTERN (temp1)) == 1
1773 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1774 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1775 && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1777 && (temp2 = prev_active_insn (temp1))
1778 && no_labels_between_p (temp2, temp1)
1779 && condjump_p (temp2)
1780 && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
1781 && (temp3 = prev_active_insn (temp2))
1782 && no_labels_between_p (temp3, temp2)
1783 && GET_CODE (PATTERN (temp3)) == SET
1784 && rtx_equal_p (SET_DEST (PATTERN (temp3)),
1785 SET_DEST (PATTERN (temp1)))
1786 && rtx_equal_p (SET_SRC (PATTERN (temp1)),
1787 SET_SRC (PATTERN (temp3)))
1788 && ! inequality_comparisons_p (PATTERN (temp))
1789 && inequality_comparisons_p (PATTERN (temp2)))
1791 rtx fallthrough_label = JUMP_LABEL (temp2);
1793 ++LABEL_NUSES (fallthrough_label);
1794 if (swap_jump (temp2, JUMP_LABEL (insn)))
1800 if (--LABEL_NUSES (fallthrough_label) == 0)
1801 delete_insn (fallthrough_label);
1804 /* Simplify if (...) {... x = 1;} if (x) ...
1806 We recognize this case backwards.
1808 TEMP is the test of `x';
1809 TEMP1 is the assignment to `x' at the end of the
1810 previous statement. */
1811 /* @@ This should call get_condition to find the values being
1812 compared, instead of looking for a COMPARE insn when HAVE_cc0
1813 is not defined. This would allow it to work on the m88k. */
1814 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1815 is not defined and the condition is tested by a separate compare
1816 insn. This is because the code below assumes that the result
1817 of the compare dies in the following branch. */
1819 /* ??? This has to be turned off. The problem is that the
1820 unconditional jump might indirectly end up branching to the
1821 label between TEMP1 and TEMP. We can't detect this, in general,
1822 since it may become a jump to there after further optimizations.
1823 If that jump is done, it will be deleted, so we will retry
1824 this optimization in the next pass, thus an infinite loop.
1826 The present code prevents this by putting the jump after the
1827 label, but this is not logically correct. */
1829 else if (this_is_condjump
1830 /* Safe to skip USE and CLOBBER insns here
1831 since they will not be deleted. */
1832 && (temp = prev_active_insn (insn))
1833 && no_labels_between_p (temp, insn)
1834 && GET_CODE (temp) == INSN
1835 && GET_CODE (PATTERN (temp)) == SET
1837 && sets_cc0_p (PATTERN (temp)) == 1
1838 && GET_CODE (SET_SRC (PATTERN (temp))) == REG
1840 /* Temp must be a compare insn, we can not accept a register
1841 to register move here, since it may not be simply a
1843 && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
1844 && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
1845 && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
1846 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1847 && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
1849 /* May skip USE or CLOBBER insns here
1850 for checking for opportunity, since we
1851 take care of them later. */
1852 && (temp1 = prev_active_insn (temp))
1853 && GET_CODE (temp1) == INSN
1854 && GET_CODE (PATTERN (temp1)) == SET
1856 && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
1858 && (XEXP (SET_SRC (PATTERN (temp)), 0)
1859 == SET_DEST (PATTERN (temp1)))
1861 && CONSTANT_P (SET_SRC (PATTERN (temp1)))
1862 /* If this isn't true, cse will do the job. */
1863 && ! no_labels_between_p (temp1, temp))
1865 /* Get the if_then_else from the condjump. */
1866 rtx choice = SET_SRC (PATTERN (insn));
1867 if (GET_CODE (choice) == IF_THEN_ELSE
1868 && (GET_CODE (XEXP (choice, 0)) == EQ
1869 || GET_CODE (XEXP (choice, 0)) == NE))
1871 int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
1876 /* Get the place that condjump will jump to
1877 if it is reached from here. */
1878 if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
1880 ultimate = XEXP (choice, 1);
1882 ultimate = XEXP (choice, 2);
1883 /* Get it as a CODE_LABEL. */
1884 if (ultimate == pc_rtx)
1885 ultimate = get_label_after (insn);
1887 /* Get the label out of the LABEL_REF. */
1888 ultimate = XEXP (ultimate, 0);
1890 /* Insert the jump immediately before TEMP, specifically
1891 after the label that is between TEMP1 and TEMP. */
1892 last_insn = PREV_INSN (temp);
1894 /* If we would be branching to the next insn, the jump
1895 would immediately be deleted and the re-inserted in
1896 a subsequent pass over the code. So don't do anything
1898 if (next_active_insn (last_insn)
1899 != next_active_insn (ultimate))
1901 emit_barrier_after (last_insn);
1902 p = emit_jump_insn_after (gen_jump (ultimate),
1904 JUMP_LABEL (p) = ultimate;
1905 ++LABEL_NUSES (ultimate);
1906 if (INSN_UID (ultimate) < max_jump_chain
1907 && INSN_CODE (p) < max_jump_chain)
1909 jump_chain[INSN_UID (p)]
1910 = jump_chain[INSN_UID (ultimate)];
1911 jump_chain[INSN_UID (ultimate)] = p;
1919 /* Detect a conditional jump going to the same place
1920 as an immediately following unconditional jump. */
1921 else if (this_is_condjump
1922 && (temp = next_active_insn (insn)) != 0
1923 && simplejump_p (temp)
1924 && (next_active_insn (JUMP_LABEL (insn))
1925 == next_active_insn (JUMP_LABEL (temp))))
1929 /* ??? Optional. Disables some optimizations, but makes
1930 gcov output more accurate with -O. */
1931 if (flag_test_coverage && !reload_completed)
1932 for (tem = insn; tem != temp; tem = NEXT_INSN (tem))
1933 if (GET_CODE (tem) == NOTE && NOTE_LINE_NUMBER (tem) > 0)
1944 /* Detect a conditional jump jumping over an unconditional trap. */
1946 && this_is_condjump && ! this_is_simplejump
1947 && reallabelprev != 0
1948 && GET_CODE (reallabelprev) == INSN
1949 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
1950 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
1951 && prev_active_insn (reallabelprev) == insn
1952 && no_labels_between_p (insn, reallabelprev)
1953 && (temp2 = get_condition (insn, &temp4))
1954 && can_reverse_comparison_p (temp2, insn))
1956 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
1957 XEXP (temp2, 0), XEXP (temp2, 1),
1958 TRAP_CODE (PATTERN (reallabelprev)));
1962 emit_insn_before (new, temp4);
1963 delete_insn (reallabelprev);
1969 /* Detect a jump jumping to an unconditional trap. */
1970 else if (HAVE_trap && this_is_condjump
1971 && (temp = next_active_insn (JUMP_LABEL (insn)))
1972 && GET_CODE (temp) == INSN
1973 && GET_CODE (PATTERN (temp)) == TRAP_IF
1974 && (this_is_simplejump
1975 || (temp2 = get_condition (insn, &temp4))))
1977 rtx tc = TRAP_CONDITION (PATTERN (temp));
1979 if (tc == const_true_rtx
1980 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
1983 /* Replace an unconditional jump to a trap with a trap. */
1984 if (this_is_simplejump)
1986 emit_barrier_after (emit_insn_before (gen_trap (), insn));
1991 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
1993 TRAP_CODE (PATTERN (temp)));
1996 emit_insn_before (new, temp4);
2002 /* If the trap condition and jump condition are mutually
2003 exclusive, redirect the jump to the following insn. */
2004 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
2005 && ! this_is_simplejump
2006 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
2007 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
2008 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
2009 && redirect_jump (insn, get_label_after (temp)))
2017 /* Detect a conditional jump jumping over an unconditional jump. */
2019 else if ((this_is_condjump || this_is_condjump_in_parallel)
2020 && ! this_is_simplejump
2021 && reallabelprev != 0
2022 && GET_CODE (reallabelprev) == JUMP_INSN
2023 && prev_active_insn (reallabelprev) == insn
2024 && no_labels_between_p (insn, reallabelprev)
2025 && simplejump_p (reallabelprev))
2027 /* When we invert the unconditional jump, we will be
2028 decrementing the usage count of its old label.
2029 Make sure that we don't delete it now because that
2030 might cause the following code to be deleted. */
2031 rtx prev_uses = prev_nonnote_insn (reallabelprev);
2032 rtx prev_label = JUMP_LABEL (insn);
2035 ++LABEL_NUSES (prev_label);
2037 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
2039 /* It is very likely that if there are USE insns before
2040 this jump, they hold REG_DEAD notes. These REG_DEAD
2041 notes are no longer valid due to this optimization,
2042 and will cause the life-analysis that following passes
2043 (notably delayed-branch scheduling) to think that
2044 these registers are dead when they are not.
2046 To prevent this trouble, we just remove the USE insns
2047 from the insn chain. */
2049 while (prev_uses && GET_CODE (prev_uses) == INSN
2050 && GET_CODE (PATTERN (prev_uses)) == USE)
2052 rtx useless = prev_uses;
2053 prev_uses = prev_nonnote_insn (prev_uses);
2054 delete_insn (useless);
2057 delete_insn (reallabelprev);
2062 /* We can now safely delete the label if it is unreferenced
2063 since the delete_insn above has deleted the BARRIER. */
2064 if (prev_label && --LABEL_NUSES (prev_label) == 0)
2065 delete_insn (prev_label);
2070 /* Detect a jump to a jump. */
2072 nlabel = follow_jumps (JUMP_LABEL (insn));
2073 if (nlabel != JUMP_LABEL (insn)
2074 && redirect_jump (insn, nlabel))
2080 /* Look for if (foo) bar; else break; */
2081 /* The insns look like this:
2082 insn = condjump label1;
2083 ...range1 (some insns)...
2086 ...range2 (some insns)...
2087 jump somewhere unconditionally
2090 rtx label1 = next_label (insn);
2091 rtx range1end = label1 ? prev_active_insn (label1) : 0;
2092 /* Don't do this optimization on the first round, so that
2093 jump-around-a-jump gets simplified before we ask here
2094 whether a jump is unconditional.
2096 Also don't do it when we are called after reload since
2097 it will confuse reorg. */
2099 && (reload_completed ? ! flag_delayed_branch : 1)
2100 /* Make sure INSN is something we can invert. */
2101 && condjump_p (insn)
2103 && JUMP_LABEL (insn) == label1
2104 && LABEL_NUSES (label1) == 1
2105 && GET_CODE (range1end) == JUMP_INSN
2106 && simplejump_p (range1end))
2108 rtx label2 = next_label (label1);
2109 rtx range2end = label2 ? prev_active_insn (label2) : 0;
2110 if (range1end != range2end
2111 && JUMP_LABEL (range1end) == label2
2112 && GET_CODE (range2end) == JUMP_INSN
2113 && GET_CODE (NEXT_INSN (range2end)) == BARRIER
2114 /* Invert the jump condition, so we
2115 still execute the same insns in each case. */
2116 && invert_jump (insn, label1))
2118 rtx range1beg = next_active_insn (insn);
2119 rtx range2beg = next_active_insn (label1);
2120 rtx range1after, range2after;
2121 rtx range1before, range2before;
2124 /* Include in each range any notes before it, to be
2125 sure that we get the line number note if any, even
2126 if there are other notes here. */
2127 while (PREV_INSN (range1beg)
2128 && GET_CODE (PREV_INSN (range1beg)) == NOTE)
2129 range1beg = PREV_INSN (range1beg);
2131 while (PREV_INSN (range2beg)
2132 && GET_CODE (PREV_INSN (range2beg)) == NOTE)
2133 range2beg = PREV_INSN (range2beg);
2135 /* Don't move NOTEs for blocks or loops; shift them
2136 outside the ranges, where they'll stay put. */
2137 range1beg = squeeze_notes (range1beg, range1end);
2138 range2beg = squeeze_notes (range2beg, range2end);
2140 /* Get current surrounds of the 2 ranges. */
2141 range1before = PREV_INSN (range1beg);
2142 range2before = PREV_INSN (range2beg);
2143 range1after = NEXT_INSN (range1end);
2144 range2after = NEXT_INSN (range2end);
2146 /* Splice range2 where range1 was. */
2147 NEXT_INSN (range1before) = range2beg;
2148 PREV_INSN (range2beg) = range1before;
2149 NEXT_INSN (range2end) = range1after;
2150 PREV_INSN (range1after) = range2end;
2151 /* Splice range1 where range2 was. */
2152 NEXT_INSN (range2before) = range1beg;
2153 PREV_INSN (range1beg) = range2before;
2154 NEXT_INSN (range1end) = range2after;
2155 PREV_INSN (range2after) = range1end;
2157 /* Check for a loop end note between the end of
2158 range2, and the next code label. If there is one,
2159 then what we have really seen is
2160 if (foo) break; end_of_loop;
2161 and moved the break sequence outside the loop.
2162 We must move the LOOP_END note to where the
2163 loop really ends now, or we will confuse loop
2164 optimization. Stop if we find a LOOP_BEG note
2165 first, since we don't want to move the LOOP_END
2166 note in that case. */
2167 for (;range2after != label2; range2after = rangenext)
2169 rangenext = NEXT_INSN (range2after);
2170 if (GET_CODE (range2after) == NOTE)
2172 if (NOTE_LINE_NUMBER (range2after)
2173 == NOTE_INSN_LOOP_END)
2175 NEXT_INSN (PREV_INSN (range2after))
2177 PREV_INSN (rangenext)
2178 = PREV_INSN (range2after);
2179 PREV_INSN (range2after)
2180 = PREV_INSN (range1beg);
2181 NEXT_INSN (range2after) = range1beg;
2182 NEXT_INSN (PREV_INSN (range1beg))
2184 PREV_INSN (range1beg) = range2after;
2186 else if (NOTE_LINE_NUMBER (range2after)
2187 == NOTE_INSN_LOOP_BEG)
2197 /* Now that the jump has been tensioned,
2198 try cross jumping: check for identical code
2199 before the jump and before its target label. */
2201 /* First, cross jumping of conditional jumps: */
2203 if (cross_jump && condjump_p (insn))
2205 rtx newjpos, newlpos;
2206 rtx x = prev_real_insn (JUMP_LABEL (insn));
2208 /* A conditional jump may be crossjumped
2209 only if the place it jumps to follows
2210 an opposing jump that comes back here. */
2212 if (x != 0 && ! jump_back_p (x, insn))
2213 /* We have no opposing jump;
2214 cannot cross jump this insn. */
2218 /* TARGET is nonzero if it is ok to cross jump
2219 to code before TARGET. If so, see if matches. */
2221 find_cross_jump (insn, x, 2,
2222 &newjpos, &newlpos);
2226 do_cross_jump (insn, newjpos, newlpos);
2227 /* Make the old conditional jump
2228 into an unconditional one. */
2229 SET_SRC (PATTERN (insn))
2230 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2231 INSN_CODE (insn) = -1;
2232 emit_barrier_after (insn);
2233 /* Add to jump_chain unless this is a new label
2234 whose UID is too large. */
2235 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2237 jump_chain[INSN_UID (insn)]
2238 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2239 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2246 /* Cross jumping of unconditional jumps:
2247 a few differences. */
2249 if (cross_jump && simplejump_p (insn))
2251 rtx newjpos, newlpos;
2256 /* TARGET is nonzero if it is ok to cross jump
2257 to code before TARGET. If so, see if matches. */
2258 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2259 &newjpos, &newlpos);
2261 /* If cannot cross jump to code before the label,
2262 see if we can cross jump to another jump to
2264 /* Try each other jump to this label. */
2265 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2266 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2267 target != 0 && newjpos == 0;
2268 target = jump_chain[INSN_UID (target)])
2270 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2271 /* Ignore TARGET if it's deleted. */
2272 && ! INSN_DELETED_P (target))
2273 find_cross_jump (insn, target, 2,
2274 &newjpos, &newlpos);
2278 do_cross_jump (insn, newjpos, newlpos);
2284 /* This code was dead in the previous jump.c! */
2285 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2287 /* Return insns all "jump to the same place"
2288 so we can cross-jump between any two of them. */
2290 rtx newjpos, newlpos, target;
2294 /* If cannot cross jump to code before the label,
2295 see if we can cross jump to another jump to
2297 /* Try each other jump to this label. */
2298 for (target = jump_chain[0];
2299 target != 0 && newjpos == 0;
2300 target = jump_chain[INSN_UID (target)])
2302 && ! INSN_DELETED_P (target)
2303 && GET_CODE (PATTERN (target)) == RETURN)
2304 find_cross_jump (insn, target, 2,
2305 &newjpos, &newlpos);
2309 do_cross_jump (insn, newjpos, newlpos);
2320 /* Delete extraneous line number notes.
2321 Note that two consecutive notes for different lines are not really
2322 extraneous. There should be some indication where that line belonged,
2323 even if it became empty. */
2328 for (insn = f; insn; insn = NEXT_INSN (insn))
2329 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2331 /* Delete this note if it is identical to previous note. */
2333 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2334 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2347 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2348 in front of it. If the machine allows it at this point (we might be
2349 after reload for a leaf routine), it will improve optimization for it
2350 to be there. We do this both here and at the start of this pass since
2351 the RETURN might have been deleted by some of our optimizations. */
2352 insn = get_last_insn ();
2353 while (insn && GET_CODE (insn) == NOTE)
2354 insn = PREV_INSN (insn);
2356 if (insn && GET_CODE (insn) != BARRIER)
2358 emit_jump_insn (gen_return ());
2364 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2365 If so, delete it, and record that this function can drop off the end. */
2371 /* One label can follow the end-note: the return label. */
2372 && ((GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2373 /* Ordinary insns can follow it if returning a structure. */
2374 || GET_CODE (insn) == INSN
2375 /* If machine uses explicit RETURN insns, no epilogue,
2376 then one of them follows the note. */
2377 || (GET_CODE (insn) == JUMP_INSN
2378 && GET_CODE (PATTERN (insn)) == RETURN)
2379 /* A barrier can follow the return insn. */
2380 || GET_CODE (insn) == BARRIER
2381 /* Other kinds of notes can follow also. */
2382 || (GET_CODE (insn) == NOTE
2383 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)))
2384 insn = PREV_INSN (insn);
2387 /* Report if control can fall through at the end of the function. */
2388 if (insn && GET_CODE (insn) == NOTE
2389 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
2395 /* Show JUMP_CHAIN no longer valid. */
2399 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2400 jump. Assume that this unconditional jump is to the exit test code. If
2401 the code is sufficiently simple, make a copy of it before INSN,
2402 followed by a jump to the exit of the loop. Then delete the unconditional
2405 Return 1 if we made the change, else 0.
2407 This is only safe immediately after a regscan pass because it uses the
2408 values of regno_first_uid and regno_last_uid. */
2411 duplicate_loop_exit_test (loop_start)
2414 rtx insn, set, reg, p, link;
2417 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2419 int max_reg = max_reg_num ();
2422 /* Scan the exit code. We do not perform this optimization if any insn:
2426 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2427 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2428 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2432 We also do not do this if we find an insn with ASM_OPERANDS. While
2433 this restriction should not be necessary, copying an insn with
2434 ASM_OPERANDS can confuse asm_noperands in some cases.
2436 Also, don't do this if the exit code is more than 20 insns. */
2438 for (insn = exitcode;
2440 && ! (GET_CODE (insn) == NOTE
2441 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2442 insn = NEXT_INSN (insn))
2444 switch (GET_CODE (insn))
2450 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2451 a jump immediately after the loop start that branches outside
2452 the loop but within an outer loop, near the exit test.
2453 If we copied this exit test and created a phony
2454 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2455 before the exit test look like these could be safely moved
2456 out of the loop even if they actually may be never executed.
2457 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2459 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2460 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2464 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2465 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2466 /* If we were to duplicate this code, we would not move
2467 the BLOCK notes, and so debugging the moved code would
2468 be difficult. Thus, we only move the code with -O2 or
2475 if (++num_insns > 20
2476 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2477 || find_reg_note (insn, REG_LIBCALL, NULL_RTX)
2478 || asm_noperands (PATTERN (insn)) > 0)
2486 /* Unless INSN is zero, we can do the optimization. */
2492 /* See if any insn sets a register only used in the loop exit code and
2493 not a user variable. If so, replace it with a new register. */
2494 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2495 if (GET_CODE (insn) == INSN
2496 && (set = single_set (insn)) != 0
2497 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2498 || (GET_CODE (reg) == SUBREG
2499 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2500 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2501 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2503 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2504 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2509 /* We can do the replacement. Allocate reg_map if this is the
2510 first replacement we found. */
2513 reg_map = (rtx *) alloca (max_reg * sizeof (rtx));
2514 bzero ((char *) reg_map, max_reg * sizeof (rtx));
2517 REG_LOOP_TEST_P (reg) = 1;
2519 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2523 /* Now copy each insn. */
2524 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2525 switch (GET_CODE (insn))
2528 copy = emit_barrier_before (loop_start);
2531 /* Only copy line-number notes. */
2532 if (NOTE_LINE_NUMBER (insn) >= 0)
2534 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2535 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2540 copy = emit_insn_before (copy_rtx (PATTERN (insn)), loop_start);
2542 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2544 mark_jump_label (PATTERN (copy), copy, 0);
2546 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2548 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2549 if (REG_NOTE_KIND (link) != REG_LABEL)
2551 = copy_rtx (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2554 if (reg_map && REG_NOTES (copy))
2555 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2559 copy = emit_jump_insn_before (copy_rtx (PATTERN (insn)), loop_start);
2561 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2562 mark_jump_label (PATTERN (copy), copy, 0);
2563 if (REG_NOTES (insn))
2565 REG_NOTES (copy) = copy_rtx (REG_NOTES (insn));
2567 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2570 /* If this is a simple jump, add it to the jump chain. */
2572 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2573 && simplejump_p (copy))
2575 jump_chain[INSN_UID (copy)]
2576 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2577 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2585 /* Now clean up by emitting a jump to the end label and deleting the jump
2586 at the start of the loop. */
2587 if (! copy || GET_CODE (copy) != BARRIER)
2589 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2591 mark_jump_label (PATTERN (copy), copy, 0);
2592 if (INSN_UID (copy) < max_jump_chain
2593 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2595 jump_chain[INSN_UID (copy)]
2596 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2597 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2599 emit_barrier_before (loop_start);
2602 /* Mark the exit code as the virtual top of the converted loop. */
2603 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2605 delete_insn (next_nonnote_insn (loop_start));
2610 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2611 loop-end notes between START and END out before START. Assume that
2612 END is not such a note. START may be such a note. Returns the value
2613 of the new starting insn, which may be different if the original start
2617 squeeze_notes (start, end)
2623 for (insn = start; insn != end; insn = next)
2625 next = NEXT_INSN (insn);
2626 if (GET_CODE (insn) == NOTE
2627 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
2628 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2629 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2630 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
2631 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
2632 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
2638 rtx prev = PREV_INSN (insn);
2639 PREV_INSN (insn) = PREV_INSN (start);
2640 NEXT_INSN (insn) = start;
2641 NEXT_INSN (PREV_INSN (insn)) = insn;
2642 PREV_INSN (NEXT_INSN (insn)) = insn;
2643 NEXT_INSN (prev) = next;
2644 PREV_INSN (next) = prev;
2652 /* Compare the instructions before insn E1 with those before E2
2653 to find an opportunity for cross jumping.
2654 (This means detecting identical sequences of insns followed by
2655 jumps to the same place, or followed by a label and a jump
2656 to that label, and replacing one with a jump to the other.)
2658 Assume E1 is a jump that jumps to label E2
2659 (that is not always true but it might as well be).
2660 Find the longest possible equivalent sequences
2661 and store the first insns of those sequences into *F1 and *F2.
2662 Store zero there if no equivalent preceding instructions are found.
2664 We give up if we find a label in stream 1.
2665 Actually we could transfer that label into stream 2. */
2668 find_cross_jump (e1, e2, minimum, f1, f2)
2673 register rtx i1 = e1, i2 = e2;
2674 register rtx p1, p2;
2677 rtx last1 = 0, last2 = 0;
2678 rtx afterlast1 = 0, afterlast2 = 0;
2685 i1 = prev_nonnote_insn (i1);
2687 i2 = PREV_INSN (i2);
2688 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
2689 i2 = PREV_INSN (i2);
2694 /* Don't allow the range of insns preceding E1 or E2
2695 to include the other (E2 or E1). */
2696 if (i2 == e1 || i1 == e2)
2699 /* If we will get to this code by jumping, those jumps will be
2700 tensioned to go directly to the new label (before I2),
2701 so this cross-jumping won't cost extra. So reduce the minimum. */
2702 if (GET_CODE (i1) == CODE_LABEL)
2708 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
2714 /* If this is a CALL_INSN, compare register usage information.
2715 If we don't check this on stack register machines, the two
2716 CALL_INSNs might be merged leaving reg-stack.c with mismatching
2717 numbers of stack registers in the same basic block.
2718 If we don't check this on machines with delay slots, a delay slot may
2719 be filled that clobbers a parameter expected by the subroutine.
2721 ??? We take the simple route for now and assume that if they're
2722 equal, they were constructed identically. */
2724 if (GET_CODE (i1) == CALL_INSN
2725 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
2726 CALL_INSN_FUNCTION_USAGE (i2)))
2730 /* If cross_jump_death_matters is not 0, the insn's mode
2731 indicates whether or not the insn contains any stack-like
2734 if (!lose && cross_jump_death_matters && GET_MODE (i1) == QImode)
2736 /* If register stack conversion has already been done, then
2737 death notes must also be compared before it is certain that
2738 the two instruction streams match. */
2741 HARD_REG_SET i1_regset, i2_regset;
2743 CLEAR_HARD_REG_SET (i1_regset);
2744 CLEAR_HARD_REG_SET (i2_regset);
2746 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
2747 if (REG_NOTE_KIND (note) == REG_DEAD
2748 && STACK_REG_P (XEXP (note, 0)))
2749 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
2751 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
2752 if (REG_NOTE_KIND (note) == REG_DEAD
2753 && STACK_REG_P (XEXP (note, 0)))
2754 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
2756 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
2765 /* Don't allow old-style asm or volatile extended asms to be accepted
2766 for cross jumping purposes. It is conceptually correct to allow
2767 them, since cross-jumping preserves the dynamic instruction order
2768 even though it is changing the static instruction order. However,
2769 if an asm is being used to emit an assembler pseudo-op, such as
2770 the MIPS `.set reorder' pseudo-op, then the static instruction order
2771 matters and it must be preserved. */
2772 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
2773 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
2774 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
2777 if (lose || GET_CODE (p1) != GET_CODE (p2)
2778 || ! rtx_renumbered_equal_p (p1, p2))
2780 /* The following code helps take care of G++ cleanups. */
2784 if (!lose && GET_CODE (p1) == GET_CODE (p2)
2785 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
2786 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
2787 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
2788 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
2789 /* If the equivalences are not to a constant, they may
2790 reference pseudos that no longer exist, so we can't
2792 && CONSTANT_P (XEXP (equiv1, 0))
2793 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
2795 rtx s1 = single_set (i1);
2796 rtx s2 = single_set (i2);
2797 if (s1 != 0 && s2 != 0
2798 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
2800 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
2801 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
2802 if (! rtx_renumbered_equal_p (p1, p2))
2804 else if (apply_change_group ())
2809 /* Insns fail to match; cross jumping is limited to the following
2813 /* Don't allow the insn after a compare to be shared by
2814 cross-jumping unless the compare is also shared.
2815 Here, if either of these non-matching insns is a compare,
2816 exclude the following insn from possible cross-jumping. */
2817 if (sets_cc0_p (p1) || sets_cc0_p (p2))
2818 last1 = afterlast1, last2 = afterlast2, ++minimum;
2821 /* If cross-jumping here will feed a jump-around-jump
2822 optimization, this jump won't cost extra, so reduce
2824 if (GET_CODE (i1) == JUMP_INSN
2826 && prev_real_insn (JUMP_LABEL (i1)) == e1)
2832 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
2834 /* Ok, this insn is potentially includable in a cross-jump here. */
2835 afterlast1 = last1, afterlast2 = last2;
2836 last1 = i1, last2 = i2, --minimum;
2840 if (minimum <= 0 && last1 != 0 && last1 != e1)
2841 *f1 = last1, *f2 = last2;
2845 do_cross_jump (insn, newjpos, newlpos)
2846 rtx insn, newjpos, newlpos;
2848 /* Find an existing label at this point
2849 or make a new one if there is none. */
2850 register rtx label = get_label_before (newlpos);
2852 /* Make the same jump insn jump to the new point. */
2853 if (GET_CODE (PATTERN (insn)) == RETURN)
2855 /* Remove from jump chain of returns. */
2856 delete_from_jump_chain (insn);
2857 /* Change the insn. */
2858 PATTERN (insn) = gen_jump (label);
2859 INSN_CODE (insn) = -1;
2860 JUMP_LABEL (insn) = label;
2861 LABEL_NUSES (label)++;
2862 /* Add to new the jump chain. */
2863 if (INSN_UID (label) < max_jump_chain
2864 && INSN_UID (insn) < max_jump_chain)
2866 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
2867 jump_chain[INSN_UID (label)] = insn;
2871 redirect_jump (insn, label);
2873 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
2874 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
2875 the NEWJPOS stream. */
2877 while (newjpos != insn)
2881 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
2882 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
2883 || REG_NOTE_KIND (lnote) == REG_EQUIV)
2884 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
2885 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
2886 remove_note (newlpos, lnote);
2888 delete_insn (newjpos);
2889 newjpos = next_real_insn (newjpos);
2890 newlpos = next_real_insn (newlpos);
2894 /* Return the label before INSN, or put a new label there. */
2897 get_label_before (insn)
2902 /* Find an existing label at this point
2903 or make a new one if there is none. */
2904 label = prev_nonnote_insn (insn);
2906 if (label == 0 || GET_CODE (label) != CODE_LABEL)
2908 rtx prev = PREV_INSN (insn);
2910 label = gen_label_rtx ();
2911 emit_label_after (label, prev);
2912 LABEL_NUSES (label) = 0;
2917 /* Return the label after INSN, or put a new label there. */
2920 get_label_after (insn)
2925 /* Find an existing label at this point
2926 or make a new one if there is none. */
2927 label = next_nonnote_insn (insn);
2929 if (label == 0 || GET_CODE (label) != CODE_LABEL)
2931 label = gen_label_rtx ();
2932 emit_label_after (label, insn);
2933 LABEL_NUSES (label) = 0;
2938 /* Return 1 if INSN is a jump that jumps to right after TARGET
2939 only on the condition that TARGET itself would drop through.
2940 Assumes that TARGET is a conditional jump. */
2943 jump_back_p (insn, target)
2947 enum rtx_code codei, codet;
2949 if (simplejump_p (insn) || ! condjump_p (insn)
2950 || simplejump_p (target)
2951 || target != prev_real_insn (JUMP_LABEL (insn)))
2954 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
2955 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
2957 codei = GET_CODE (cinsn);
2958 codet = GET_CODE (ctarget);
2960 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
2962 if (! can_reverse_comparison_p (cinsn, insn))
2964 codei = reverse_condition (codei);
2967 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
2969 if (! can_reverse_comparison_p (ctarget, target))
2971 codet = reverse_condition (codet);
2974 return (codei == codet
2975 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
2976 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
2979 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
2980 return non-zero if it is safe to reverse this comparison. It is if our
2981 floating-point is not IEEE, if this is an NE or EQ comparison, or if
2982 this is known to be an integer comparison. */
2985 can_reverse_comparison_p (comparison, insn)
2991 /* If this is not actually a comparison, we can't reverse it. */
2992 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
2995 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
2996 /* If this is an NE comparison, it is safe to reverse it to an EQ
2997 comparison and vice versa, even for floating point. If no operands
2998 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
2999 always false and NE is always true, so the reversal is also valid. */
3001 || GET_CODE (comparison) == NE
3002 || GET_CODE (comparison) == EQ)
3005 arg0 = XEXP (comparison, 0);
3007 /* Make sure ARG0 is one of the actual objects being compared. If we
3008 can't do this, we can't be sure the comparison can be reversed.
3010 Handle cc0 and a MODE_CC register. */
3011 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3017 rtx prev = prev_nonnote_insn (insn);
3018 rtx set = single_set (prev);
3020 if (set == 0 || SET_DEST (set) != arg0)
3023 arg0 = SET_SRC (set);
3025 if (GET_CODE (arg0) == COMPARE)
3026 arg0 = XEXP (arg0, 0);
3029 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3030 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3031 return (GET_CODE (arg0) == CONST_INT
3032 || (GET_MODE (arg0) != VOIDmode
3033 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3034 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3037 /* Given an rtx-code for a comparison, return the code
3038 for the negated comparison.
3039 WATCH OUT! reverse_condition is not safe to use on a jump
3040 that might be acting on the results of an IEEE floating point comparison,
3041 because of the special treatment of non-signaling nans in comparisons.
3042 Use can_reverse_comparison_p to be sure. */
3045 reverse_condition (code)
3086 /* Similar, but return the code when two operands of a comparison are swapped.
3087 This IS safe for IEEE floating-point. */
3090 swap_condition (code)
3129 /* Given a comparison CODE, return the corresponding unsigned comparison.
3130 If CODE is an equality comparison or already an unsigned comparison,
3131 CODE is returned. */
3134 unsigned_condition (code)
3164 /* Similarly, return the signed version of a comparison. */
3167 signed_condition (code)
3197 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3198 truth of CODE1 implies the truth of CODE2. */
3201 comparison_dominates_p (code1, code2)
3202 enum rtx_code code1, code2;
3210 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
3215 if (code2 == LE || code2 == NE)
3220 if (code2 == GE || code2 == NE)
3225 if (code2 == LEU || code2 == NE)
3230 if (code2 == GEU || code2 == NE)
3241 /* Return 1 if INSN is an unconditional jump and nothing else. */
3247 return (GET_CODE (insn) == JUMP_INSN
3248 && GET_CODE (PATTERN (insn)) == SET
3249 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3250 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3253 /* Return nonzero if INSN is a (possibly) conditional jump
3254 and nothing more. */
3260 register rtx x = PATTERN (insn);
3261 if (GET_CODE (x) != SET)
3263 if (GET_CODE (SET_DEST (x)) != PC)
3265 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3267 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3269 if (XEXP (SET_SRC (x), 2) == pc_rtx
3270 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3271 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3273 if (XEXP (SET_SRC (x), 1) == pc_rtx
3274 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3275 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3280 /* Return nonzero if INSN is a (possibly) conditional jump
3281 and nothing more. */
3284 condjump_in_parallel_p (insn)
3287 register rtx x = PATTERN (insn);
3289 if (GET_CODE (x) != PARALLEL)
3292 x = XVECEXP (x, 0, 0);
3294 if (GET_CODE (x) != SET)
3296 if (GET_CODE (SET_DEST (x)) != PC)
3298 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3300 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3302 if (XEXP (SET_SRC (x), 2) == pc_rtx
3303 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3304 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3306 if (XEXP (SET_SRC (x), 1) == pc_rtx
3307 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3308 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3313 /* Return 1 if X is an RTX that does nothing but set the condition codes
3314 and CLOBBER or USE registers.
3315 Return -1 if X does explicitly set the condition codes,
3316 but also does other things. */
3323 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3325 if (GET_CODE (x) == PARALLEL)
3329 int other_things = 0;
3330 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3332 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3333 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3335 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3338 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3346 /* Follow any unconditional jump at LABEL;
3347 return the ultimate label reached by any such chain of jumps.
3348 If LABEL is not followed by a jump, return LABEL.
3349 If the chain loops or we can't find end, return LABEL,
3350 since that tells caller to avoid changing the insn.
3352 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3353 a USE or CLOBBER. */
3356 follow_jumps (label)
3361 register rtx value = label;
3366 && (insn = next_active_insn (value)) != 0
3367 && GET_CODE (insn) == JUMP_INSN
3368 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3369 || GET_CODE (PATTERN (insn)) == RETURN)
3370 && (next = NEXT_INSN (insn))
3371 && GET_CODE (next) == BARRIER);
3374 /* Don't chain through the insn that jumps into a loop
3375 from outside the loop,
3376 since that would create multiple loop entry jumps
3377 and prevent loop optimization. */
3379 if (!reload_completed)
3380 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3381 if (GET_CODE (tem) == NOTE
3382 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3383 /* ??? Optional. Disables some optimizations, but makes
3384 gcov output more accurate with -O. */
3385 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3388 /* If we have found a cycle, make the insn jump to itself. */
3389 if (JUMP_LABEL (insn) == label)
3392 tem = next_active_insn (JUMP_LABEL (insn));
3393 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3394 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3397 value = JUMP_LABEL (insn);
3404 /* Assuming that field IDX of X is a vector of label_refs,
3405 replace each of them by the ultimate label reached by it.
3406 Return nonzero if a change is made.
3407 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3410 tension_vector_labels (x, idx)
3416 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3418 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3419 register rtx nlabel = follow_jumps (olabel);
3420 if (nlabel && nlabel != olabel)
3422 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3423 ++LABEL_NUSES (nlabel);
3424 if (--LABEL_NUSES (olabel) == 0)
3425 delete_insn (olabel);
3432 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3433 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3434 in INSN, then store one of them in JUMP_LABEL (INSN).
3435 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3436 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3437 Also, when there are consecutive labels, canonicalize on the last of them.
3439 Note that two labels separated by a loop-beginning note
3440 must be kept distinct if we have not yet done loop-optimization,
3441 because the gap between them is where loop-optimize
3442 will want to move invariant code to. CROSS_JUMP tells us
3443 that loop-optimization is done with.
3445 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3446 two labels distinct if they are separated by only USE or CLOBBER insns. */
3449 mark_jump_label (x, insn, cross_jump)
3454 register RTX_CODE code = GET_CODE (x);
3472 /* If this is a constant-pool reference, see if it is a label. */
3473 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3474 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3475 mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
3480 rtx label = XEXP (x, 0);
3485 if (GET_CODE (label) != CODE_LABEL)
3488 /* Ignore references to labels of containing functions. */
3489 if (LABEL_REF_NONLOCAL_P (x))
3492 /* If there are other labels following this one,
3493 replace it with the last of the consecutive labels. */
3494 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3496 if (GET_CODE (next) == CODE_LABEL)
3498 else if (cross_jump && GET_CODE (next) == INSN
3499 && (GET_CODE (PATTERN (next)) == USE
3500 || GET_CODE (PATTERN (next)) == CLOBBER))
3502 else if (GET_CODE (next) != NOTE)
3504 else if (! cross_jump
3505 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3506 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3507 /* ??? Optional. Disables some optimizations, but
3508 makes gcov output more accurate with -O. */
3509 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3513 XEXP (x, 0) = label;
3514 if (! insn || ! INSN_DELETED_P (insn))
3515 ++LABEL_NUSES (label);
3519 if (GET_CODE (insn) == JUMP_INSN)
3520 JUMP_LABEL (insn) = label;
3522 /* If we've changed OLABEL and we had a REG_LABEL note
3523 for it, update it as well. */
3524 else if (label != olabel
3525 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
3526 XEXP (note, 0) = label;
3528 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3530 else if (! find_reg_note (insn, REG_LABEL, label))
3532 /* This code used to ignore labels which refered to dispatch
3533 tables to avoid flow.c generating worse code.
3535 However, in the presense of global optimizations like
3536 gcse which call find_basic_blocks without calling
3537 life_analysis, not recording such labels will lead
3538 to compiler aborts because of inconsistencies in the
3539 flow graph. So we go ahead and record the label.
3541 It may also be the case that the optimization argument
3542 is no longer valid because of the more accurate cfg
3543 we build in find_basic_blocks -- it no longer pessimizes
3544 code when it finds a REG_LABEL note. */
3545 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
3552 /* Do walk the labels in a vector, but not the first operand of an
3553 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
3556 if (! INSN_DELETED_P (insn))
3558 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
3560 for (i = 0; i < XVECLEN (x, eltnum); i++)
3561 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
3569 fmt = GET_RTX_FORMAT (code);
3570 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3573 mark_jump_label (XEXP (x, i), insn, cross_jump);
3574 else if (fmt[i] == 'E')
3577 for (j = 0; j < XVECLEN (x, i); j++)
3578 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
3583 /* If all INSN does is set the pc, delete it,
3584 and delete the insn that set the condition codes for it
3585 if that's what the previous thing was. */
3591 register rtx set = single_set (insn);
3593 if (set && GET_CODE (SET_DEST (set)) == PC)
3594 delete_computation (insn);
3597 /* Delete INSN and recursively delete insns that compute values used only
3598 by INSN. This uses the REG_DEAD notes computed during flow analysis.
3599 If we are running before flow.c, we need do nothing since flow.c will
3600 delete dead code. We also can't know if the registers being used are
3601 dead or not at this point.
3603 Otherwise, look at all our REG_DEAD notes. If a previous insn does
3604 nothing other than set a register that dies in this insn, we can delete
3607 On machines with CC0, if CC0 is used in this insn, we may be able to
3608 delete the insn that set it. */
3611 delete_computation (insn)
3617 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
3619 rtx prev = prev_nonnote_insn (insn);
3620 /* We assume that at this stage
3621 CC's are always set explicitly
3622 and always immediately before the jump that
3623 will use them. So if the previous insn
3624 exists to set the CC's, delete it
3625 (unless it performs auto-increments, etc.). */
3626 if (prev && GET_CODE (prev) == INSN
3627 && sets_cc0_p (PATTERN (prev)))
3629 if (sets_cc0_p (PATTERN (prev)) > 0
3630 && !FIND_REG_INC_NOTE (prev, NULL_RTX))
3631 delete_computation (prev);
3633 /* Otherwise, show that cc0 won't be used. */
3634 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
3635 cc0_rtx, REG_NOTES (prev));
3640 for (note = REG_NOTES (insn); note; note = next)
3644 next = XEXP (note, 1);
3646 if (REG_NOTE_KIND (note) != REG_DEAD
3647 /* Verify that the REG_NOTE is legitimate. */
3648 || GET_CODE (XEXP (note, 0)) != REG)
3651 for (our_prev = prev_nonnote_insn (insn);
3652 our_prev && GET_CODE (our_prev) == INSN;
3653 our_prev = prev_nonnote_insn (our_prev))
3655 /* If we reach a SEQUENCE, it is too complex to try to
3656 do anything with it, so give up. */
3657 if (GET_CODE (PATTERN (our_prev)) == SEQUENCE)
3660 if (GET_CODE (PATTERN (our_prev)) == USE
3661 && GET_CODE (XEXP (PATTERN (our_prev), 0)) == INSN)
3662 /* reorg creates USEs that look like this. We leave them
3663 alone because reorg needs them for its own purposes. */
3666 if (reg_set_p (XEXP (note, 0), PATTERN (our_prev)))
3668 if (FIND_REG_INC_NOTE (our_prev, NULL_RTX))
3671 if (GET_CODE (PATTERN (our_prev)) == PARALLEL)
3673 /* If we find a SET of something else, we can't
3678 for (i = 0; i < XVECLEN (PATTERN (our_prev), 0); i++)
3680 rtx part = XVECEXP (PATTERN (our_prev), 0, i);
3682 if (GET_CODE (part) == SET
3683 && SET_DEST (part) != XEXP (note, 0))
3687 if (i == XVECLEN (PATTERN (our_prev), 0))
3688 delete_computation (our_prev);
3690 else if (GET_CODE (PATTERN (our_prev)) == SET
3691 && SET_DEST (PATTERN (our_prev)) == XEXP (note, 0))
3692 delete_computation (our_prev);
3697 /* If OUR_PREV references the register that dies here, it is an
3698 additional use. Hence any prior SET isn't dead. However, this
3699 insn becomes the new place for the REG_DEAD note. */
3700 if (reg_overlap_mentioned_p (XEXP (note, 0),
3701 PATTERN (our_prev)))
3703 XEXP (note, 1) = REG_NOTES (our_prev);
3704 REG_NOTES (our_prev) = note;
3713 /* Delete insn INSN from the chain of insns and update label ref counts.
3714 May delete some following insns as a consequence; may even delete
3715 a label elsewhere and insns that follow it.
3717 Returns the first insn after INSN that was not deleted. */
3723 register rtx next = NEXT_INSN (insn);
3724 register rtx prev = PREV_INSN (insn);
3725 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
3726 register int dont_really_delete = 0;
3728 while (next && INSN_DELETED_P (next))
3729 next = NEXT_INSN (next);
3731 /* This insn is already deleted => return first following nondeleted. */
3732 if (INSN_DELETED_P (insn))
3735 /* Don't delete user-declared labels. Convert them to special NOTEs
3737 if (was_code_label && LABEL_NAME (insn) != 0
3738 && optimize && ! dont_really_delete)
3740 PUT_CODE (insn, NOTE);
3741 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
3742 NOTE_SOURCE_FILE (insn) = 0;
3743 dont_really_delete = 1;
3746 /* Mark this insn as deleted. */
3747 INSN_DELETED_P (insn) = 1;
3749 /* If this is an unconditional jump, delete it from the jump chain. */
3750 if (simplejump_p (insn))
3751 delete_from_jump_chain (insn);
3753 /* If instruction is followed by a barrier,
3754 delete the barrier too. */
3756 if (next != 0 && GET_CODE (next) == BARRIER)
3758 INSN_DELETED_P (next) = 1;
3759 next = NEXT_INSN (next);
3762 /* Patch out INSN (and the barrier if any) */
3764 if (optimize && ! dont_really_delete)
3768 NEXT_INSN (prev) = next;
3769 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
3770 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
3771 XVECLEN (PATTERN (prev), 0) - 1)) = next;
3776 PREV_INSN (next) = prev;
3777 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
3778 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
3781 if (prev && NEXT_INSN (prev) == 0)
3782 set_last_insn (prev);
3785 /* If deleting a jump, decrement the count of the label,
3786 and delete the label if it is now unused. */
3788 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
3789 if (--LABEL_NUSES (JUMP_LABEL (insn)) == 0)
3791 /* This can delete NEXT or PREV,
3792 either directly if NEXT is JUMP_LABEL (INSN),
3793 or indirectly through more levels of jumps. */
3794 delete_insn (JUMP_LABEL (insn));
3795 /* I feel a little doubtful about this loop,
3796 but I see no clean and sure alternative way
3797 to find the first insn after INSN that is not now deleted.
3798 I hope this works. */
3799 while (next && INSN_DELETED_P (next))
3800 next = NEXT_INSN (next);
3804 /* Likewise if we're deleting a dispatch table. */
3806 if (GET_CODE (insn) == JUMP_INSN
3807 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
3808 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
3810 rtx pat = PATTERN (insn);
3811 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
3812 int len = XVECLEN (pat, diff_vec_p);
3814 for (i = 0; i < len; i++)
3815 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
3816 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
3817 while (next && INSN_DELETED_P (next))
3818 next = NEXT_INSN (next);
3822 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
3823 prev = PREV_INSN (prev);
3825 /* If INSN was a label and a dispatch table follows it,
3826 delete the dispatch table. The tablejump must have gone already.
3827 It isn't useful to fall through into a table. */
3830 && NEXT_INSN (insn) != 0
3831 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
3832 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
3833 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
3834 next = delete_insn (NEXT_INSN (insn));
3836 /* If INSN was a label, delete insns following it if now unreachable. */
3838 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
3840 register RTX_CODE code;
3842 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
3843 || code == NOTE || code == BARRIER
3844 || (code == CODE_LABEL && INSN_DELETED_P (next))))
3847 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
3848 next = NEXT_INSN (next);
3849 /* Keep going past other deleted labels to delete what follows. */
3850 else if (code == CODE_LABEL && INSN_DELETED_P (next))
3851 next = NEXT_INSN (next);
3853 /* Note: if this deletes a jump, it can cause more
3854 deletion of unreachable code, after a different label.
3855 As long as the value from this recursive call is correct,
3856 this invocation functions correctly. */
3857 next = delete_insn (next);
3864 /* Advance from INSN till reaching something not deleted
3865 then return that. May return INSN itself. */
3868 next_nondeleted_insn (insn)
3871 while (INSN_DELETED_P (insn))
3872 insn = NEXT_INSN (insn);
3876 /* Delete a range of insns from FROM to TO, inclusive.
3877 This is for the sake of peephole optimization, so assume
3878 that whatever these insns do will still be done by a new
3879 peephole insn that will replace them. */
3882 delete_for_peephole (from, to)
3883 register rtx from, to;
3885 register rtx insn = from;
3889 register rtx next = NEXT_INSN (insn);
3890 register rtx prev = PREV_INSN (insn);
3892 if (GET_CODE (insn) != NOTE)
3894 INSN_DELETED_P (insn) = 1;
3896 /* Patch this insn out of the chain. */
3897 /* We don't do this all at once, because we
3898 must preserve all NOTEs. */
3900 NEXT_INSN (prev) = next;
3903 PREV_INSN (next) = prev;
3911 /* Note that if TO is an unconditional jump
3912 we *do not* delete the BARRIER that follows,
3913 since the peephole that replaces this sequence
3914 is also an unconditional jump in that case. */
3917 /* Invert the condition of the jump JUMP, and make it jump
3918 to label NLABEL instead of where it jumps now. */
3921 invert_jump (jump, nlabel)
3924 /* We have to either invert the condition and change the label or
3925 do neither. Either operation could fail. We first try to invert
3926 the jump. If that succeeds, we try changing the label. If that fails,
3927 we invert the jump back to what it was. */
3929 if (! invert_exp (PATTERN (jump), jump))
3932 if (redirect_jump (jump, nlabel))
3934 if (flag_branch_probabilities)
3936 rtx note = find_reg_note (jump, REG_BR_PROB, 0);
3938 /* An inverted jump means that a probability taken becomes a
3939 probability not taken. Subtract the branch probability from the
3940 probability base to convert it back to a taken probability.
3941 (We don't flip the probability on a branch that's never taken. */
3942 if (note && XINT (XEXP (note, 0), 0) >= 0)
3943 XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
3949 if (! invert_exp (PATTERN (jump), jump))
3950 /* This should just be putting it back the way it was. */
3956 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3958 Return 1 if we can do so, 0 if we cannot find a way to do so that
3959 matches a pattern. */
3962 invert_exp (x, insn)
3966 register RTX_CODE code;
3970 code = GET_CODE (x);
3972 if (code == IF_THEN_ELSE)
3974 register rtx comp = XEXP (x, 0);
3977 /* We can do this in two ways: The preferable way, which can only
3978 be done if this is not an integer comparison, is to reverse
3979 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3980 of the IF_THEN_ELSE. If we can't do either, fail. */
3982 if (can_reverse_comparison_p (comp, insn)
3983 && validate_change (insn, &XEXP (x, 0),
3984 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
3985 GET_MODE (comp), XEXP (comp, 0),
3986 XEXP (comp, 1)), 0))
3990 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3991 validate_change (insn, &XEXP (x, 2), tem, 1);
3992 return apply_change_group ();
3995 fmt = GET_RTX_FORMAT (code);
3996 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3999 if (! invert_exp (XEXP (x, i), insn))
4004 for (j = 0; j < XVECLEN (x, i); j++)
4005 if (!invert_exp (XVECEXP (x, i, j), insn))
4013 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4014 If the old jump target label is unused as a result,
4015 it and the code following it may be deleted.
4017 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4020 The return value will be 1 if the change was made, 0 if it wasn't (this
4021 can only occur for NLABEL == 0). */
4024 redirect_jump (jump, nlabel)
4027 register rtx olabel = JUMP_LABEL (jump);
4029 if (nlabel == olabel)
4032 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4035 /* If this is an unconditional branch, delete it from the jump_chain of
4036 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4037 have UID's in range and JUMP_CHAIN is valid). */
4038 if (jump_chain && (simplejump_p (jump)
4039 || GET_CODE (PATTERN (jump)) == RETURN))
4041 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4043 delete_from_jump_chain (jump);
4044 if (label_index < max_jump_chain
4045 && INSN_UID (jump) < max_jump_chain)
4047 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4048 jump_chain[label_index] = jump;
4052 JUMP_LABEL (jump) = nlabel;
4054 ++LABEL_NUSES (nlabel);
4056 if (olabel && --LABEL_NUSES (olabel) == 0)
4057 delete_insn (olabel);
4062 /* Delete the instruction JUMP from any jump chain it might be on. */
4065 delete_from_jump_chain (jump)
4069 rtx olabel = JUMP_LABEL (jump);
4071 /* Handle unconditional jumps. */
4072 if (jump_chain && olabel != 0
4073 && INSN_UID (olabel) < max_jump_chain
4074 && simplejump_p (jump))
4075 index = INSN_UID (olabel);
4076 /* Handle return insns. */
4077 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4081 if (jump_chain[index] == jump)
4082 jump_chain[index] = jump_chain[INSN_UID (jump)];
4087 for (insn = jump_chain[index];
4089 insn = jump_chain[INSN_UID (insn)])
4090 if (jump_chain[INSN_UID (insn)] == jump)
4092 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4098 /* If NLABEL is nonzero, throughout the rtx at LOC,
4099 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4100 zero, alter (RETURN) to (LABEL_REF NLABEL).
4102 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4103 validity with validate_change. Convert (set (pc) (label_ref olabel))
4106 Return 0 if we found a change we would like to make but it is invalid.
4107 Otherwise, return 1. */
4110 redirect_exp (loc, olabel, nlabel, insn)
4115 register rtx x = *loc;
4116 register RTX_CODE code = GET_CODE (x);
4120 if (code == LABEL_REF)
4122 if (XEXP (x, 0) == olabel)
4125 XEXP (x, 0) = nlabel;
4127 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4131 else if (code == RETURN && olabel == 0)
4133 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4134 if (loc == &PATTERN (insn))
4135 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4136 return validate_change (insn, loc, x, 0);
4139 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4140 && GET_CODE (SET_SRC (x)) == LABEL_REF
4141 && XEXP (SET_SRC (x), 0) == olabel)
4142 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4144 fmt = GET_RTX_FORMAT (code);
4145 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4148 if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
4153 for (j = 0; j < XVECLEN (x, i); j++)
4154 if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
4162 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4164 If the old jump target label (before the dispatch table) becomes unused,
4165 it and the dispatch table may be deleted. In that case, find the insn
4166 before the jump references that label and delete it and logical successors
4170 redirect_tablejump (jump, nlabel)
4173 register rtx olabel = JUMP_LABEL (jump);
4175 /* Add this jump to the jump_chain of NLABEL. */
4176 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4177 && INSN_UID (jump) < max_jump_chain)
4179 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4180 jump_chain[INSN_UID (nlabel)] = jump;
4183 PATTERN (jump) = gen_jump (nlabel);
4184 JUMP_LABEL (jump) = nlabel;
4185 ++LABEL_NUSES (nlabel);
4186 INSN_CODE (jump) = -1;
4188 if (--LABEL_NUSES (olabel) == 0)
4190 delete_labelref_insn (jump, olabel, 0);
4191 delete_insn (olabel);
4195 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4196 If we found one, delete it and then delete this insn if DELETE_THIS is
4197 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4200 delete_labelref_insn (insn, label, delete_this)
4207 if (GET_CODE (insn) != NOTE
4208 && reg_mentioned_p (label, PATTERN (insn)))
4219 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4220 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4234 /* Like rtx_equal_p except that it considers two REGs as equal
4235 if they renumber to the same value and considers two commutative
4236 operations to be the same if the order of the operands has been
4240 rtx_renumbered_equal_p (x, y)
4244 register RTX_CODE code = GET_CODE (x);
4250 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4251 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4252 && GET_CODE (SUBREG_REG (y)) == REG)))
4254 int reg_x = -1, reg_y = -1;
4255 int word_x = 0, word_y = 0;
4257 if (GET_MODE (x) != GET_MODE (y))
4260 /* If we haven't done any renumbering, don't
4261 make any assumptions. */
4262 if (reg_renumber == 0)
4263 return rtx_equal_p (x, y);
4267 reg_x = REGNO (SUBREG_REG (x));
4268 word_x = SUBREG_WORD (x);
4270 if (reg_renumber[reg_x] >= 0)
4272 reg_x = reg_renumber[reg_x] + word_x;
4280 if (reg_renumber[reg_x] >= 0)
4281 reg_x = reg_renumber[reg_x];
4284 if (GET_CODE (y) == SUBREG)
4286 reg_y = REGNO (SUBREG_REG (y));
4287 word_y = SUBREG_WORD (y);
4289 if (reg_renumber[reg_y] >= 0)
4291 reg_y = reg_renumber[reg_y];
4299 if (reg_renumber[reg_y] >= 0)
4300 reg_y = reg_renumber[reg_y];
4303 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4306 /* Now we have disposed of all the cases
4307 in which different rtx codes can match. */
4308 if (code != GET_CODE (y))
4320 return INTVAL (x) == INTVAL (y);
4323 /* We can't assume nonlocal labels have their following insns yet. */
4324 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4325 return XEXP (x, 0) == XEXP (y, 0);
4327 /* Two label-refs are equivalent if they point at labels
4328 in the same position in the instruction stream. */
4329 return (next_real_insn (XEXP (x, 0))
4330 == next_real_insn (XEXP (y, 0)));
4333 return XSTR (x, 0) == XSTR (y, 0);
4339 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4341 if (GET_MODE (x) != GET_MODE (y))
4344 /* For commutative operations, the RTX match if the operand match in any
4345 order. Also handle the simple binary and unary cases without a loop. */
4346 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4347 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4348 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
4349 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
4350 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
4351 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4352 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4353 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
4354 else if (GET_RTX_CLASS (code) == '1')
4355 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
4357 /* Compare the elements. If any pair of corresponding elements
4358 fail to match, return 0 for the whole things. */
4360 fmt = GET_RTX_FORMAT (code);
4361 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4367 if (XWINT (x, i) != XWINT (y, i))
4372 if (XINT (x, i) != XINT (y, i))
4377 if (strcmp (XSTR (x, i), XSTR (y, i)))
4382 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
4387 if (XEXP (x, i) != XEXP (y, i))
4394 if (XVECLEN (x, i) != XVECLEN (y, i))
4396 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4397 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
4408 /* If X is a hard register or equivalent to one or a subregister of one,
4409 return the hard register number. If X is a pseudo register that was not
4410 assigned a hard register, return the pseudo register number. Otherwise,
4411 return -1. Any rtx is valid for X. */
4417 if (GET_CODE (x) == REG)
4419 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
4420 return reg_renumber[REGNO (x)];
4423 if (GET_CODE (x) == SUBREG)
4425 int base = true_regnum (SUBREG_REG (x));
4426 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
4427 return SUBREG_WORD (x) + base;
4432 /* Optimize code of the form:
4434 for (x = a[i]; x; ...)
4436 for (x = a[i]; x; ...)
4440 Loop optimize will change the above code into
4444 { ...; if (! (x = ...)) break; }
4447 { ...; if (! (x = ...)) break; }
4450 In general, if the first test fails, the program can branch
4451 directly to `foo' and skip the second try which is doomed to fail.
4452 We run this after loop optimization and before flow analysis. */
4454 /* When comparing the insn patterns, we track the fact that different
4455 pseudo-register numbers may have been used in each computation.
4456 The following array stores an equivalence -- same_regs[I] == J means
4457 that pseudo register I was used in the first set of tests in a context
4458 where J was used in the second set. We also count the number of such
4459 pending equivalences. If nonzero, the expressions really aren't the
4462 static int *same_regs;
4464 static int num_same_regs;
4466 /* Track any registers modified between the target of the first jump and
4467 the second jump. They never compare equal. */
4469 static char *modified_regs;
4471 /* Record if memory was modified. */
4473 static int modified_mem;
4475 /* Called via note_stores on each insn between the target of the first
4476 branch and the second branch. It marks any changed registers. */
4479 mark_modified_reg (dest, x)
4481 rtx x ATTRIBUTE_UNUSED;
4485 if (GET_CODE (dest) == SUBREG)
4486 dest = SUBREG_REG (dest);
4488 if (GET_CODE (dest) == MEM)
4491 if (GET_CODE (dest) != REG)
4494 regno = REGNO (dest);
4495 if (regno >= FIRST_PSEUDO_REGISTER)
4496 modified_regs[regno] = 1;
4498 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
4499 modified_regs[regno + i] = 1;
4502 /* F is the first insn in the chain of insns. */
4505 thread_jumps (f, max_reg, flag_before_loop)
4508 int flag_before_loop;
4510 /* Basic algorithm is to find a conditional branch,
4511 the label it may branch to, and the branch after
4512 that label. If the two branches test the same condition,
4513 walk back from both branch paths until the insn patterns
4514 differ, or code labels are hit. If we make it back to
4515 the target of the first branch, then we know that the first branch
4516 will either always succeed or always fail depending on the relative
4517 senses of the two branches. So adjust the first branch accordingly
4520 rtx label, b1, b2, t1, t2;
4521 enum rtx_code code1, code2;
4522 rtx b1op0, b1op1, b2op0, b2op1;
4527 /* Allocate register tables and quick-reset table. */
4528 modified_regs = (char *) alloca (max_reg * sizeof (char));
4529 same_regs = (int *) alloca (max_reg * sizeof (int));
4530 all_reset = (int *) alloca (max_reg * sizeof (int));
4531 for (i = 0; i < max_reg; i++)
4538 for (b1 = f; b1; b1 = NEXT_INSN (b1))
4540 /* Get to a candidate branch insn. */
4541 if (GET_CODE (b1) != JUMP_INSN
4542 || ! condjump_p (b1) || simplejump_p (b1)
4543 || JUMP_LABEL (b1) == 0)
4546 bzero (modified_regs, max_reg * sizeof (char));
4549 bcopy ((char *) all_reset, (char *) same_regs,
4550 max_reg * sizeof (int));
4553 label = JUMP_LABEL (b1);
4555 /* Look for a branch after the target. Record any registers and
4556 memory modified between the target and the branch. Stop when we
4557 get to a label since we can't know what was changed there. */
4558 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
4560 if (GET_CODE (b2) == CODE_LABEL)
4563 else if (GET_CODE (b2) == JUMP_INSN)
4565 /* If this is an unconditional jump and is the only use of
4566 its target label, we can follow it. */
4567 if (simplejump_p (b2)
4568 && JUMP_LABEL (b2) != 0
4569 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
4571 b2 = JUMP_LABEL (b2);
4578 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
4581 if (GET_CODE (b2) == CALL_INSN)
4584 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4585 if (call_used_regs[i] && ! fixed_regs[i]
4586 && i != STACK_POINTER_REGNUM
4587 && i != FRAME_POINTER_REGNUM
4588 && i != HARD_FRAME_POINTER_REGNUM
4589 && i != ARG_POINTER_REGNUM)
4590 modified_regs[i] = 1;
4593 note_stores (PATTERN (b2), mark_modified_reg);
4596 /* Check the next candidate branch insn from the label
4599 || GET_CODE (b2) != JUMP_INSN
4601 || ! condjump_p (b2)
4602 || simplejump_p (b2))
4605 /* Get the comparison codes and operands, reversing the
4606 codes if appropriate. If we don't have comparison codes,
4607 we can't do anything. */
4608 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
4609 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
4610 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
4611 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
4612 code1 = reverse_condition (code1);
4614 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
4615 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
4616 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
4617 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
4618 code2 = reverse_condition (code2);
4620 /* If they test the same things and knowing that B1 branches
4621 tells us whether or not B2 branches, check if we
4622 can thread the branch. */
4623 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
4624 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
4625 && (comparison_dominates_p (code1, code2)
4626 || (comparison_dominates_p (code1, reverse_condition (code2))
4627 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
4631 t1 = prev_nonnote_insn (b1);
4632 t2 = prev_nonnote_insn (b2);
4634 while (t1 != 0 && t2 != 0)
4638 /* We have reached the target of the first branch.
4639 If there are no pending register equivalents,
4640 we know that this branch will either always
4641 succeed (if the senses of the two branches are
4642 the same) or always fail (if not). */
4645 if (num_same_regs != 0)
4648 if (comparison_dominates_p (code1, code2))
4649 new_label = JUMP_LABEL (b2);
4651 new_label = get_label_after (b2);
4653 if (JUMP_LABEL (b1) != new_label)
4655 rtx prev = PREV_INSN (new_label);
4657 if (flag_before_loop
4658 && GET_CODE (prev) == NOTE
4659 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
4661 /* Don't thread to the loop label. If a loop
4662 label is reused, loop optimization will
4663 be disabled for that loop. */
4664 new_label = gen_label_rtx ();
4665 emit_label_after (new_label, PREV_INSN (prev));
4667 changed |= redirect_jump (b1, new_label);
4672 /* If either of these is not a normal insn (it might be
4673 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
4674 have already been skipped above.) Similarly, fail
4675 if the insns are different. */
4676 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
4677 || recog_memoized (t1) != recog_memoized (t2)
4678 || ! rtx_equal_for_thread_p (PATTERN (t1),
4682 t1 = prev_nonnote_insn (t1);
4683 t2 = prev_nonnote_insn (t2);
4690 /* This is like RTX_EQUAL_P except that it knows about our handling of
4691 possibly equivalent registers and knows to consider volatile and
4692 modified objects as not equal.
4694 YINSN is the insn containing Y. */
4697 rtx_equal_for_thread_p (x, y, yinsn)
4703 register enum rtx_code code;
4706 code = GET_CODE (x);
4707 /* Rtx's of different codes cannot be equal. */
4708 if (code != GET_CODE (y))
4711 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4712 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4714 if (GET_MODE (x) != GET_MODE (y))
4717 /* For floating-point, consider everything unequal. This is a bit
4718 pessimistic, but this pass would only rarely do anything for FP
4720 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
4721 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
4724 /* For commutative operations, the RTX match if the operand match in any
4725 order. Also handle the simple binary and unary cases without a loop. */
4726 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4727 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4728 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
4729 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
4730 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
4731 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4732 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4733 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
4734 else if (GET_RTX_CLASS (code) == '1')
4735 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4737 /* Handle special-cases first. */
4741 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
4744 /* If neither is user variable or hard register, check for possible
4746 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
4747 || REGNO (x) < FIRST_PSEUDO_REGISTER
4748 || REGNO (y) < FIRST_PSEUDO_REGISTER)
4751 if (same_regs[REGNO (x)] == -1)
4753 same_regs[REGNO (x)] = REGNO (y);
4756 /* If this is the first time we are seeing a register on the `Y'
4757 side, see if it is the last use. If not, we can't thread the
4758 jump, so mark it as not equivalent. */
4759 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4765 return (same_regs[REGNO (x)] == REGNO (y));
4770 /* If memory modified or either volatile, not equivalent.
4771 Else, check address. */
4772 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4775 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4778 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4784 /* Cancel a pending `same_regs' if setting equivalenced registers.
4785 Then process source. */
4786 if (GET_CODE (SET_DEST (x)) == REG
4787 && GET_CODE (SET_DEST (y)) == REG)
4789 if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
4791 same_regs[REGNO (SET_DEST (x))] = -1;
4794 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4798 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4801 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4804 return XEXP (x, 0) == XEXP (y, 0);
4807 return XSTR (x, 0) == XSTR (y, 0);
4816 fmt = GET_RTX_FORMAT (code);
4817 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4822 if (XWINT (x, i) != XWINT (y, i))
4828 if (XINT (x, i) != XINT (y, i))
4834 /* Two vectors must have the same length. */
4835 if (XVECLEN (x, i) != XVECLEN (y, i))
4838 /* And the corresponding elements must match. */
4839 for (j = 0; j < XVECLEN (x, i); j++)
4840 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4841 XVECEXP (y, i, j), yinsn) == 0)
4846 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4852 if (strcmp (XSTR (x, i), XSTR (y, i)))
4857 /* These are just backpointers, so they don't matter. */
4863 /* It is believed that rtx's at this level will never
4864 contain anything but integers and other rtx's,
4865 except for within LABEL_REFs and SYMBOL_REFs. */
4875 /* Return the insn that NEW can be safely inserted in front of starting at
4876 the jump insn INSN. Return 0 if it is not safe to do this jump
4877 optimization. Note that NEW must contain a single set. */
4880 find_insert_position (insn, new)
4887 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
4888 if (GET_CODE (PATTERN (new)) != PARALLEL)
4891 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
4892 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
4893 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
4900 /* There is a good chance that the previous insn PREV sets the thing
4901 being clobbered (often the CC in a hard reg). If PREV does not
4902 use what NEW sets, we can insert NEW before PREV. */
4904 prev = prev_active_insn (insn);
4905 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
4906 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
4907 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
4909 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
4913 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
4915 #endif /* !HAVE_cc0 */