1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-96, 1997 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. */
57 #include "hard-reg-set.h"
59 #include "insn-config.h"
60 #include "insn-flags.h"
65 /* ??? Eventually must record somehow the labels used by jumps
66 from nested functions. */
67 /* Pre-record the next or previous real insn for each label?
68 No, this pass is very fast anyway. */
69 /* Condense consecutive labels?
70 This would make life analysis faster, maybe. */
71 /* Optimize jump y; x: ... y: jumpif... x?
72 Don't know if it is worth bothering with. */
73 /* Optimize two cases of conditional jump to conditional jump?
74 This can never delete any instruction or make anything dead,
75 or even change what is live at any point.
76 So perhaps let combiner do it. */
78 /* Vector indexed by uid.
79 For each CODE_LABEL, index by its uid to get first unconditional jump
80 that jumps to the label.
81 For each JUMP_INSN, index by its uid to get the next unconditional jump
82 that jumps to the same label.
83 Element 0 is the start of a chain of all return insns.
84 (It is safe to use element 0 because insn uid 0 is not used. */
86 static rtx
*jump_chain
;
88 /* List of labels referred to from initializers.
89 These can never be deleted. */
92 /* Maximum index in jump_chain. */
94 static int max_jump_chain
;
96 /* Set nonzero by jump_optimize if control can fall through
97 to the end of the function. */
100 /* Indicates whether death notes are significant in cross jump analysis.
101 Normally they are not significant, because of A and B jump to C,
102 and R dies in A, it must die in B. But this might not be true after
103 stack register conversion, and we must compare death notes in that
106 static int cross_jump_death_matters
= 0;
108 static int duplicate_loop_exit_test
PROTO((rtx
));
109 static void find_cross_jump
PROTO((rtx
, rtx
, int, rtx
*, rtx
*));
110 static void do_cross_jump
PROTO((rtx
, rtx
, rtx
));
111 static int jump_back_p
PROTO((rtx
, rtx
));
112 static int tension_vector_labels
PROTO((rtx
, int));
113 static void mark_jump_label
PROTO((rtx
, rtx
, int));
114 static void delete_computation
PROTO((rtx
));
115 static void delete_from_jump_chain
PROTO((rtx
));
116 static int delete_labelref_insn
PROTO((rtx
, rtx
, int));
117 static void redirect_tablejump
PROTO((rtx
, rtx
));
119 /* Delete no-op jumps and optimize jumps to jumps
120 and jumps around jumps.
121 Delete unused labels and unreachable code.
123 If CROSS_JUMP is 1, detect matching code
124 before a jump and its destination and unify them.
125 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
127 If NOOP_MOVES is nonzero, delete no-op move insns.
129 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
130 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
132 If `optimize' is zero, don't change any code,
133 just determine whether control drops off the end of the function.
134 This case occurs when we have -W and not -O.
135 It works because `delete_insn' checks the value of `optimize'
136 and refrains from actually deleting when that is 0. */
139 jump_optimize (f
, cross_jump
, noop_moves
, after_regscan
)
145 register rtx insn
, next
, note
;
151 cross_jump_death_matters
= (cross_jump
== 2);
153 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
154 notes whose labels don't occur in the insn any more. */
156 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
158 if (GET_CODE (insn
) == CODE_LABEL
)
159 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
160 else if (GET_CODE (insn
) == JUMP_INSN
)
161 JUMP_LABEL (insn
) = 0;
162 else if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
163 for (note
= REG_NOTES (insn
); note
; note
= next
)
165 next
= XEXP (note
, 1);
166 if (REG_NOTE_KIND (note
) == REG_LABEL
167 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
168 remove_note (insn
, note
);
171 if (INSN_UID (insn
) > max_uid
)
172 max_uid
= INSN_UID (insn
);
177 /* Delete insns following barriers, up to next label. */
179 for (insn
= f
; insn
;)
181 if (GET_CODE (insn
) == BARRIER
)
183 insn
= NEXT_INSN (insn
);
184 while (insn
!= 0 && GET_CODE (insn
) != CODE_LABEL
)
186 if (GET_CODE (insn
) == NOTE
187 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)
188 insn
= NEXT_INSN (insn
);
190 insn
= delete_insn (insn
);
192 /* INSN is now the code_label. */
195 insn
= NEXT_INSN (insn
);
198 /* Leave some extra room for labels and duplicate exit test insns
200 max_jump_chain
= max_uid
* 14 / 10;
201 jump_chain
= (rtx
*) alloca (max_jump_chain
* sizeof (rtx
));
202 bzero ((char *) jump_chain
, max_jump_chain
* sizeof (rtx
));
204 /* Mark the label each jump jumps to.
205 Combine consecutive labels, and count uses of labels.
207 For each label, make a chain (using `jump_chain')
208 of all the *unconditional* jumps that jump to it;
209 also make a chain of all returns. */
211 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
212 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
213 && ! INSN_DELETED_P (insn
))
215 mark_jump_label (PATTERN (insn
), insn
, cross_jump
);
216 if (GET_CODE (insn
) == JUMP_INSN
)
218 if (JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
220 jump_chain
[INSN_UID (insn
)]
221 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
222 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
224 if (GET_CODE (PATTERN (insn
)) == RETURN
)
226 jump_chain
[INSN_UID (insn
)] = jump_chain
[0];
227 jump_chain
[0] = insn
;
232 /* Keep track of labels used from static data;
233 they cannot ever be deleted. */
235 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
236 LABEL_NUSES (XEXP (insn
, 0))++;
238 check_exception_handler_labels ();
240 /* Keep track of labels used for marking handlers for exception
241 regions; they cannot usually be deleted. */
243 for (insn
= exception_handler_labels
; insn
; insn
= XEXP (insn
, 1))
244 LABEL_NUSES (XEXP (insn
, 0))++;
246 exception_optimize ();
248 /* Delete all labels already not referenced.
249 Also find the last insn. */
252 for (insn
= f
; insn
; )
254 if (GET_CODE (insn
) == CODE_LABEL
&& LABEL_NUSES (insn
) == 0)
255 insn
= delete_insn (insn
);
259 insn
= NEXT_INSN (insn
);
265 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
266 If so record that this function can drop off the end. */
272 /* One label can follow the end-note: the return label. */
273 && ((GET_CODE (insn
) == CODE_LABEL
&& n_labels
-- > 0)
274 /* Ordinary insns can follow it if returning a structure. */
275 || GET_CODE (insn
) == INSN
276 /* If machine uses explicit RETURN insns, no epilogue,
277 then one of them follows the note. */
278 || (GET_CODE (insn
) == JUMP_INSN
279 && GET_CODE (PATTERN (insn
)) == RETURN
)
280 /* A barrier can follow the return insn. */
281 || GET_CODE (insn
) == BARRIER
282 /* Other kinds of notes can follow also. */
283 || (GET_CODE (insn
) == NOTE
284 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)))
285 insn
= PREV_INSN (insn
);
288 /* Report if control can fall through at the end of the function. */
289 if (insn
&& GET_CODE (insn
) == NOTE
290 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_END
291 && ! INSN_DELETED_P (insn
))
294 /* Zero the "deleted" flag of all the "deleted" insns. */
295 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
296 INSN_DELETED_P (insn
) = 0;
303 /* If we fall through to the epilogue, see if we can insert a RETURN insn
304 in front of it. If the machine allows it at this point (we might be
305 after reload for a leaf routine), it will improve optimization for it
307 insn
= get_last_insn ();
308 while (insn
&& GET_CODE (insn
) == NOTE
)
309 insn
= PREV_INSN (insn
);
311 if (insn
&& GET_CODE (insn
) != BARRIER
)
313 emit_jump_insn (gen_return ());
320 for (insn
= f
; insn
; )
322 next
= NEXT_INSN (insn
);
324 if (GET_CODE (insn
) == INSN
)
326 register rtx body
= PATTERN (insn
);
328 /* Combine stack_adjusts with following push_insns. */
330 if (GET_CODE (body
) == SET
331 && SET_DEST (body
) == stack_pointer_rtx
332 && GET_CODE (SET_SRC (body
)) == PLUS
333 && XEXP (SET_SRC (body
), 0) == stack_pointer_rtx
334 && GET_CODE (XEXP (SET_SRC (body
), 1)) == CONST_INT
335 && INTVAL (XEXP (SET_SRC (body
), 1)) > 0)
338 rtx stack_adjust_insn
= insn
;
339 int stack_adjust_amount
= INTVAL (XEXP (SET_SRC (body
), 1));
340 int total_pushed
= 0;
343 /* Find all successive push insns. */
345 /* Don't convert more than three pushes;
346 that starts adding too many displaced addresses
347 and the whole thing starts becoming a losing
352 p
= next_nonnote_insn (p
);
353 if (p
== 0 || GET_CODE (p
) != INSN
)
356 if (GET_CODE (pbody
) != SET
)
358 dest
= SET_DEST (pbody
);
359 /* Allow a no-op move between the adjust and the push. */
360 if (GET_CODE (dest
) == REG
361 && GET_CODE (SET_SRC (pbody
)) == REG
362 && REGNO (dest
) == REGNO (SET_SRC (pbody
)))
364 if (! (GET_CODE (dest
) == MEM
365 && GET_CODE (XEXP (dest
, 0)) == POST_INC
366 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
369 if (total_pushed
+ GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)))
370 > stack_adjust_amount
)
372 total_pushed
+= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
375 /* Discard the amount pushed from the stack adjust;
376 maybe eliminate it entirely. */
377 if (total_pushed
>= stack_adjust_amount
)
379 delete_computation (stack_adjust_insn
);
380 total_pushed
= stack_adjust_amount
;
383 XEXP (SET_SRC (PATTERN (stack_adjust_insn
)), 1)
384 = GEN_INT (stack_adjust_amount
- total_pushed
);
386 /* Change the appropriate push insns to ordinary stores. */
388 while (total_pushed
> 0)
391 p
= next_nonnote_insn (p
);
392 if (GET_CODE (p
) != INSN
)
395 if (GET_CODE (pbody
) == SET
)
397 dest
= SET_DEST (pbody
);
398 if (! (GET_CODE (dest
) == MEM
399 && GET_CODE (XEXP (dest
, 0)) == POST_INC
400 && XEXP (XEXP (dest
, 0), 0) == stack_pointer_rtx
))
402 total_pushed
-= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody
)));
403 /* If this push doesn't fully fit in the space
404 of the stack adjust that we deleted,
405 make another stack adjust here for what we
406 didn't use up. There should be peepholes
407 to recognize the resulting sequence of insns. */
408 if (total_pushed
< 0)
410 emit_insn_before (gen_add2_insn (stack_pointer_rtx
,
411 GEN_INT (- total_pushed
)),
416 = plus_constant (stack_pointer_rtx
, total_pushed
);
421 /* Detect and delete no-op move instructions
422 resulting from not allocating a parameter in a register. */
424 if (GET_CODE (body
) == SET
425 && (SET_DEST (body
) == SET_SRC (body
)
426 || (GET_CODE (SET_DEST (body
)) == MEM
427 && GET_CODE (SET_SRC (body
)) == MEM
428 && rtx_equal_p (SET_SRC (body
), SET_DEST (body
))))
429 && ! (GET_CODE (SET_DEST (body
)) == MEM
430 && MEM_VOLATILE_P (SET_DEST (body
)))
431 && ! (GET_CODE (SET_SRC (body
)) == MEM
432 && MEM_VOLATILE_P (SET_SRC (body
))))
433 delete_computation (insn
);
435 /* Detect and ignore no-op move instructions
436 resulting from smart or fortuitous register allocation. */
438 else if (GET_CODE (body
) == SET
)
440 int sreg
= true_regnum (SET_SRC (body
));
441 int dreg
= true_regnum (SET_DEST (body
));
443 if (sreg
== dreg
&& sreg
>= 0)
445 else if (sreg
>= 0 && dreg
>= 0)
448 rtx tem
= find_equiv_reg (NULL_RTX
, insn
, 0,
449 sreg
, NULL_PTR
, dreg
,
450 GET_MODE (SET_SRC (body
)));
453 && GET_MODE (tem
) == GET_MODE (SET_DEST (body
)))
455 /* DREG may have been the target of a REG_DEAD note in
456 the insn which makes INSN redundant. If so, reorg
457 would still think it is dead. So search for such a
458 note and delete it if we find it. */
459 if (! find_regno_note (insn
, REG_UNUSED
, dreg
))
460 for (trial
= prev_nonnote_insn (insn
);
461 trial
&& GET_CODE (trial
) != CODE_LABEL
;
462 trial
= prev_nonnote_insn (trial
))
463 if (find_regno_note (trial
, REG_DEAD
, dreg
))
465 remove_death (dreg
, trial
);
468 #ifdef PRESERVE_DEATH_INFO_REGNO_P
469 /* Deleting insn could lose a death-note for SREG
470 so don't do it if final needs accurate
472 if (PRESERVE_DEATH_INFO_REGNO_P (sreg
)
473 && (trial
= find_regno_note (insn
, REG_DEAD
, sreg
)))
475 /* Change this into a USE so that we won't emit
476 code for it, but still can keep the note. */
478 = gen_rtx (USE
, VOIDmode
, XEXP (trial
, 0));
479 INSN_CODE (insn
) = -1;
480 /* Remove all reg notes but the REG_DEAD one. */
481 REG_NOTES (insn
) = trial
;
482 XEXP (trial
, 1) = NULL_RTX
;
489 else if (dreg
>= 0 && CONSTANT_P (SET_SRC (body
))
490 && find_equiv_reg (SET_SRC (body
), insn
, 0, dreg
,
492 GET_MODE (SET_DEST (body
))))
494 /* This handles the case where we have two consecutive
495 assignments of the same constant to pseudos that didn't
496 get a hard reg. Each SET from the constant will be
497 converted into a SET of the spill register and an
498 output reload will be made following it. This produces
499 two loads of the same constant into the same spill
504 /* Look back for a death note for the first reg.
505 If there is one, it is no longer accurate. */
506 while (in_insn
&& GET_CODE (in_insn
) != CODE_LABEL
)
508 if ((GET_CODE (in_insn
) == INSN
509 || GET_CODE (in_insn
) == JUMP_INSN
)
510 && find_regno_note (in_insn
, REG_DEAD
, dreg
))
512 remove_death (dreg
, in_insn
);
515 in_insn
= PREV_INSN (in_insn
);
518 /* Delete the second load of the value. */
522 else if (GET_CODE (body
) == PARALLEL
)
524 /* If each part is a set between two identical registers or
525 a USE or CLOBBER, delete the insn. */
529 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
531 tem
= XVECEXP (body
, 0, i
);
532 if (GET_CODE (tem
) == USE
|| GET_CODE (tem
) == CLOBBER
)
535 if (GET_CODE (tem
) != SET
536 || (sreg
= true_regnum (SET_SRC (tem
))) < 0
537 || (dreg
= true_regnum (SET_DEST (tem
))) < 0
545 /* Also delete insns to store bit fields if they are no-ops. */
546 /* Not worth the hair to detect this in the big-endian case. */
547 else if (! BYTES_BIG_ENDIAN
548 && GET_CODE (body
) == SET
549 && GET_CODE (SET_DEST (body
)) == ZERO_EXTRACT
550 && XEXP (SET_DEST (body
), 2) == const0_rtx
551 && XEXP (SET_DEST (body
), 0) == SET_SRC (body
)
552 && ! (GET_CODE (SET_SRC (body
)) == MEM
553 && MEM_VOLATILE_P (SET_SRC (body
))))
559 /* If we haven't yet gotten to reload and we have just run regscan,
560 delete any insn that sets a register that isn't used elsewhere.
561 This helps some of the optimizations below by having less insns
562 being jumped around. */
564 if (! reload_completed
&& after_regscan
)
565 for (insn
= f
; insn
; insn
= next
)
567 rtx set
= single_set (insn
);
569 next
= NEXT_INSN (insn
);
571 if (set
&& GET_CODE (SET_DEST (set
)) == REG
572 && REGNO (SET_DEST (set
)) >= FIRST_PSEUDO_REGISTER
573 && REGNO_FIRST_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
574 /* We use regno_last_note_uid so as not to delete the setting
575 of a reg that's used in notes. A subsequent optimization
576 might arrange to use that reg for real. */
577 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set
))) == INSN_UID (insn
)
578 && ! side_effects_p (SET_SRC (set
))
579 && ! find_reg_note (insn
, REG_RETVAL
, 0))
583 /* Now iterate optimizing jumps until nothing changes over one pass. */
589 for (insn
= f
; insn
; insn
= next
)
592 rtx temp
, temp1
, temp2
, temp3
, temp4
, temp5
, temp6
;
594 int this_is_simplejump
, this_is_condjump
, reversep
;
595 int this_is_condjump_in_parallel
;
597 /* If NOT the first iteration, if this is the last jump pass
598 (just before final), do the special peephole optimizations.
599 Avoiding the first iteration gives ordinary jump opts
600 a chance to work before peephole opts. */
602 if (reload_completed
&& !first
&& !flag_no_peephole
)
603 if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == JUMP_INSN
)
607 /* That could have deleted some insns after INSN, so check now
608 what the following insn is. */
610 next
= NEXT_INSN (insn
);
612 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
613 jump. Try to optimize by duplicating the loop exit test if so.
614 This is only safe immediately after regscan, because it uses
615 the values of regno_first_uid and regno_last_uid. */
616 if (after_regscan
&& GET_CODE (insn
) == NOTE
617 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
618 && (temp1
= next_nonnote_insn (insn
)) != 0
619 && simplejump_p (temp1
))
621 temp
= PREV_INSN (insn
);
622 if (duplicate_loop_exit_test (insn
))
625 next
= NEXT_INSN (temp
);
630 if (GET_CODE (insn
) != JUMP_INSN
)
633 this_is_simplejump
= simplejump_p (insn
);
634 this_is_condjump
= condjump_p (insn
);
635 this_is_condjump_in_parallel
= condjump_in_parallel_p (insn
);
637 /* Tension the labels in dispatch tables. */
639 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
)
640 changed
|= tension_vector_labels (PATTERN (insn
), 0);
641 if (GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
642 changed
|= tension_vector_labels (PATTERN (insn
), 1);
644 /* If a dispatch table always goes to the same place,
645 get rid of it and replace the insn that uses it. */
647 if (GET_CODE (PATTERN (insn
)) == ADDR_VEC
648 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
)
651 rtx pat
= PATTERN (insn
);
652 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
653 int len
= XVECLEN (pat
, diff_vec_p
);
654 rtx dispatch
= prev_real_insn (insn
);
656 for (i
= 0; i
< len
; i
++)
657 if (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)
658 != XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0))
662 && GET_CODE (dispatch
) == JUMP_INSN
663 && JUMP_LABEL (dispatch
) != 0
664 /* Don't mess with a casesi insn. */
665 && !(GET_CODE (PATTERN (dispatch
)) == SET
666 && (GET_CODE (SET_SRC (PATTERN (dispatch
)))
668 && next_real_insn (JUMP_LABEL (dispatch
)) == insn
)
670 redirect_tablejump (dispatch
,
671 XEXP (XVECEXP (pat
, diff_vec_p
, 0), 0));
676 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
678 /* If a jump references the end of the function, try to turn
679 it into a RETURN insn, possibly a conditional one. */
680 if (JUMP_LABEL (insn
)
681 && (next_active_insn (JUMP_LABEL (insn
)) == 0
682 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn
))))
684 changed
|= redirect_jump (insn
, NULL_RTX
);
686 /* Detect jump to following insn. */
687 if (reallabelprev
== insn
&& condjump_p (insn
))
689 next
= next_real_insn (JUMP_LABEL (insn
));
695 /* If we have an unconditional jump preceded by a USE, try to put
696 the USE before the target and jump there. This simplifies many
697 of the optimizations below since we don't have to worry about
698 dealing with these USE insns. We only do this if the label
699 being branch to already has the identical USE or if code
700 never falls through to that label. */
702 if (this_is_simplejump
703 && (temp
= prev_nonnote_insn (insn
)) != 0
704 && GET_CODE (temp
) == INSN
&& GET_CODE (PATTERN (temp
)) == USE
705 && (temp1
= prev_nonnote_insn (JUMP_LABEL (insn
))) != 0
706 && (GET_CODE (temp1
) == BARRIER
707 || (GET_CODE (temp1
) == INSN
708 && rtx_equal_p (PATTERN (temp
), PATTERN (temp1
))))
709 /* Don't do this optimization if we have a loop containing only
710 the USE instruction, and the loop start label has a usage
711 count of 1. This is because we will redo this optimization
712 everytime through the outer loop, and jump opt will never
714 && ! ((temp2
= prev_nonnote_insn (temp
)) != 0
715 && temp2
== JUMP_LABEL (insn
)
716 && LABEL_NUSES (temp2
) == 1))
718 if (GET_CODE (temp1
) == BARRIER
)
720 emit_insn_after (PATTERN (temp
), temp1
);
721 temp1
= NEXT_INSN (temp1
);
725 redirect_jump (insn
, get_label_before (temp1
));
726 reallabelprev
= prev_real_insn (temp1
);
730 /* Simplify if (...) x = a; else x = b; by converting it
731 to x = b; if (...) x = a;
732 if B is sufficiently simple, the test doesn't involve X,
733 and nothing in the test modifies B or X.
735 If we have small register classes, we also can't do this if X
738 If the "x = b;" insn has any REG_NOTES, we don't do this because
739 of the possibility that we are running after CSE and there is a
740 REG_EQUAL note that is only valid if the branch has already been
741 taken. If we move the insn with the REG_EQUAL note, we may
742 fold the comparison to always be false in a later CSE pass.
743 (We could also delete the REG_NOTES when moving the insn, but it
744 seems simpler to not move it.) An exception is that we can move
745 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
746 value is the same as "b".
748 INSN is the branch over the `else' part.
752 TEMP to the jump insn preceding "x = a;"
754 TEMP2 to the insn that sets "x = b;"
755 TEMP3 to the insn that sets "x = a;"
756 TEMP4 to the set of "x = b"; */
758 if (this_is_simplejump
759 && (temp3
= prev_active_insn (insn
)) != 0
760 && GET_CODE (temp3
) == INSN
761 && (temp4
= single_set (temp3
)) != 0
762 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
763 #ifdef SMALL_REGISTER_CLASSES
764 && (! SMALL_REGISTER_CLASSES
765 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
767 && (temp2
= next_active_insn (insn
)) != 0
768 && GET_CODE (temp2
) == INSN
769 && (temp4
= single_set (temp2
)) != 0
770 && rtx_equal_p (SET_DEST (temp4
), temp1
)
771 && (GET_CODE (SET_SRC (temp4
)) == REG
772 || GET_CODE (SET_SRC (temp4
)) == SUBREG
773 || CONSTANT_P (SET_SRC (temp4
)))
774 && (REG_NOTES (temp2
) == 0
775 || ((REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUAL
776 || REG_NOTE_KIND (REG_NOTES (temp2
)) == REG_EQUIV
)
777 && XEXP (REG_NOTES (temp2
), 1) == 0
778 && rtx_equal_p (XEXP (REG_NOTES (temp2
), 0),
780 && (temp
= prev_active_insn (temp3
)) != 0
781 && condjump_p (temp
) && ! simplejump_p (temp
)
782 /* TEMP must skip over the "x = a;" insn */
783 && prev_real_insn (JUMP_LABEL (temp
)) == insn
784 && no_labels_between_p (insn
, JUMP_LABEL (temp
))
785 /* There must be no other entries to the "x = b;" insn. */
786 && no_labels_between_p (JUMP_LABEL (temp
), temp2
)
787 /* INSN must either branch to the insn after TEMP2 or the insn
788 after TEMP2 must branch to the same place as INSN. */
789 && (reallabelprev
== temp2
790 || ((temp5
= next_active_insn (temp2
)) != 0
791 && simplejump_p (temp5
)
792 && JUMP_LABEL (temp5
) == JUMP_LABEL (insn
))))
794 /* The test expression, X, may be a complicated test with
795 multiple branches. See if we can find all the uses of
796 the label that TEMP branches to without hitting a CALL_INSN
797 or a jump to somewhere else. */
798 rtx target
= JUMP_LABEL (temp
);
799 int nuses
= LABEL_NUSES (target
);
802 /* Set P to the first jump insn that goes around "x = a;". */
803 for (p
= temp
; nuses
&& p
; p
= prev_nonnote_insn (p
))
805 if (GET_CODE (p
) == JUMP_INSN
)
807 if (condjump_p (p
) && ! simplejump_p (p
)
808 && JUMP_LABEL (p
) == target
)
817 else if (GET_CODE (p
) == CALL_INSN
)
822 /* We cannot insert anything between a set of cc and its use
823 so if P uses cc0, we must back up to the previous insn. */
824 q
= prev_nonnote_insn (p
);
825 if (q
&& GET_RTX_CLASS (GET_CODE (q
)) == 'i'
826 && sets_cc0_p (PATTERN (q
)))
833 /* If we found all the uses and there was no data conflict, we
834 can move the assignment unless we can branch into the middle
837 && no_labels_between_p (p
, insn
)
838 && ! reg_referenced_between_p (temp1
, p
, NEXT_INSN (temp3
))
839 && ! reg_set_between_p (temp1
, p
, temp3
)
840 && (GET_CODE (SET_SRC (temp4
)) == CONST_INT
841 || ! reg_set_between_p (SET_SRC (temp4
), p
, temp2
)))
843 emit_insn_after_with_line_notes (PATTERN (temp2
), p
, temp2
);
846 /* Set NEXT to an insn that we know won't go away. */
847 next
= next_active_insn (insn
);
849 /* Delete the jump around the set. Note that we must do
850 this before we redirect the test jumps so that it won't
851 delete the code immediately following the assignment
852 we moved (which might be a jump). */
856 /* We either have two consecutive labels or a jump to
857 a jump, so adjust all the JUMP_INSNs to branch to where
859 for (p
= NEXT_INSN (p
); p
!= next
; p
= NEXT_INSN (p
))
860 if (GET_CODE (p
) == JUMP_INSN
)
861 redirect_jump (p
, target
);
868 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
869 to x = a; if (...) goto l; x = b;
870 if A is sufficiently simple, the test doesn't involve X,
871 and nothing in the test modifies A or X.
873 If we have small register classes, we also can't do this if X
876 If the "x = a;" insn has any REG_NOTES, we don't do this because
877 of the possibility that we are running after CSE and there is a
878 REG_EQUAL note that is only valid if the branch has already been
879 taken. If we move the insn with the REG_EQUAL note, we may
880 fold the comparison to always be false in a later CSE pass.
881 (We could also delete the REG_NOTES when moving the insn, but it
882 seems simpler to not move it.) An exception is that we can move
883 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
884 value is the same as "a".
890 TEMP to the jump insn preceding "x = a;"
892 TEMP2 to the insn that sets "x = b;"
893 TEMP3 to the insn that sets "x = a;"
894 TEMP4 to the set of "x = a"; */
896 if (this_is_simplejump
897 && (temp2
= next_active_insn (insn
)) != 0
898 && GET_CODE (temp2
) == INSN
899 && (temp4
= single_set (temp2
)) != 0
900 && GET_CODE (temp1
= SET_DEST (temp4
)) == REG
901 #ifdef SMALL_REGISTER_CLASSES
902 && (! SMALL_REGISTER_CLASSES
903 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
906 && (temp3
= prev_active_insn (insn
)) != 0
907 && GET_CODE (temp3
) == INSN
908 && (temp4
= single_set (temp3
)) != 0
909 && rtx_equal_p (SET_DEST (temp4
), temp1
)
910 && (GET_CODE (SET_SRC (temp4
)) == REG
911 || GET_CODE (SET_SRC (temp4
)) == SUBREG
912 || CONSTANT_P (SET_SRC (temp4
)))
913 && (REG_NOTES (temp3
) == 0
914 || ((REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUAL
915 || REG_NOTE_KIND (REG_NOTES (temp3
)) == REG_EQUIV
)
916 && XEXP (REG_NOTES (temp3
), 1) == 0
917 && rtx_equal_p (XEXP (REG_NOTES (temp3
), 0),
919 && (temp
= prev_active_insn (temp3
)) != 0
920 && condjump_p (temp
) && ! simplejump_p (temp
)
921 /* TEMP must skip over the "x = a;" insn */
922 && prev_real_insn (JUMP_LABEL (temp
)) == insn
923 && no_labels_between_p (temp
, insn
))
925 rtx prev_label
= JUMP_LABEL (temp
);
926 rtx insert_after
= prev_nonnote_insn (temp
);
929 /* We cannot insert anything between a set of cc and its use. */
930 if (insert_after
&& GET_RTX_CLASS (GET_CODE (insert_after
)) == 'i'
931 && sets_cc0_p (PATTERN (insert_after
)))
932 insert_after
= prev_nonnote_insn (insert_after
);
934 ++LABEL_NUSES (prev_label
);
937 && no_labels_between_p (insert_after
, temp
)
938 && ! reg_referenced_between_p (temp1
, insert_after
, temp3
)
939 && ! reg_referenced_between_p (temp1
, temp3
,
941 && ! reg_set_between_p (temp1
, insert_after
, temp
)
942 && (GET_CODE (SET_SRC (temp4
)) == CONST_INT
943 || ! reg_set_between_p (SET_SRC (temp4
),
945 && invert_jump (temp
, JUMP_LABEL (insn
)))
947 emit_insn_after_with_line_notes (PATTERN (temp3
),
948 insert_after
, temp3
);
951 /* Set NEXT to an insn that we know won't go away. */
955 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
956 delete_insn (prev_label
);
962 /* If we have if (...) x = exp; and branches are expensive,
963 EXP is a single insn, does not have any side effects, cannot
964 trap, and is not too costly, convert this to
965 t = exp; if (...) x = t;
967 Don't do this when we have CC0 because it is unlikely to help
968 and we'd need to worry about where to place the new insn and
969 the potential for conflicts. We also can't do this when we have
970 notes on the insn for the same reason as above.
974 TEMP to the "x = exp;" insn.
975 TEMP1 to the single set in the "x = exp; insn.
978 if (! reload_completed
979 && this_is_condjump
&& ! this_is_simplejump
981 && (temp
= next_nonnote_insn (insn
)) != 0
982 && GET_CODE (temp
) == INSN
983 && REG_NOTES (temp
) == 0
984 && (reallabelprev
== temp
985 || ((temp2
= next_active_insn (temp
)) != 0
986 && simplejump_p (temp2
)
987 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
988 && (temp1
= single_set (temp
)) != 0
989 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
990 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
991 #ifdef SMALL_REGISTER_CLASSES
992 && (! SMALL_REGISTER_CLASSES
993 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
995 && GET_CODE (SET_SRC (temp1
)) != REG
996 && GET_CODE (SET_SRC (temp1
)) != SUBREG
997 && GET_CODE (SET_SRC (temp1
)) != CONST_INT
998 && ! side_effects_p (SET_SRC (temp1
))
999 && ! may_trap_p (SET_SRC (temp1
))
1000 && rtx_cost (SET_SRC (temp1
), SET
) < 10)
1002 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
1004 if (validate_change (temp
, &SET_DEST (temp1
), new, 0))
1006 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
1007 emit_insn_after_with_line_notes (PATTERN (temp
),
1008 PREV_INSN (insn
), temp
);
1010 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
1014 /* Similarly, if it takes two insns to compute EXP but they
1015 have the same destination. Here TEMP3 will be the second
1016 insn and TEMP4 the SET from that insn. */
1018 if (! reload_completed
1019 && this_is_condjump
&& ! this_is_simplejump
1021 && (temp
= next_nonnote_insn (insn
)) != 0
1022 && GET_CODE (temp
) == INSN
1023 && REG_NOTES (temp
) == 0
1024 && (temp3
= next_nonnote_insn (temp
)) != 0
1025 && GET_CODE (temp3
) == INSN
1026 && REG_NOTES (temp3
) == 0
1027 && (reallabelprev
== temp3
1028 || ((temp2
= next_active_insn (temp3
)) != 0
1029 && simplejump_p (temp2
)
1030 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
1031 && (temp1
= single_set (temp
)) != 0
1032 && (temp2
= SET_DEST (temp1
), GET_CODE (temp2
) == REG
)
1033 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
1034 #ifdef SMALL_REGISTER_CLASSES
1035 && (! SMALL_REGISTER_CLASSES
1036 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
1038 && ! side_effects_p (SET_SRC (temp1
))
1039 && ! may_trap_p (SET_SRC (temp1
))
1040 && rtx_cost (SET_SRC (temp1
), SET
) < 10
1041 && (temp4
= single_set (temp3
)) != 0
1042 && rtx_equal_p (SET_DEST (temp4
), temp2
)
1043 && ! side_effects_p (SET_SRC (temp4
))
1044 && ! may_trap_p (SET_SRC (temp4
))
1045 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
1047 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
1049 if (validate_change (temp
, &SET_DEST (temp1
), new, 0))
1051 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
1052 emit_insn_after_with_line_notes (PATTERN (temp
),
1053 PREV_INSN (insn
), temp
);
1054 emit_insn_after_with_line_notes
1055 (replace_rtx (PATTERN (temp3
), temp2
, new),
1056 PREV_INSN (insn
), temp3
);
1058 delete_insn (temp3
);
1059 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
1063 /* Finally, handle the case where two insns are used to
1064 compute EXP but a temporary register is used. Here we must
1065 ensure that the temporary register is not used anywhere else. */
1067 if (! reload_completed
1069 && this_is_condjump
&& ! this_is_simplejump
1071 && (temp
= next_nonnote_insn (insn
)) != 0
1072 && GET_CODE (temp
) == INSN
1073 && REG_NOTES (temp
) == 0
1074 && (temp3
= next_nonnote_insn (temp
)) != 0
1075 && GET_CODE (temp3
) == INSN
1076 && REG_NOTES (temp3
) == 0
1077 && (reallabelprev
== temp3
1078 || ((temp2
= next_active_insn (temp3
)) != 0
1079 && simplejump_p (temp2
)
1080 && JUMP_LABEL (temp2
) == JUMP_LABEL (insn
)))
1081 && (temp1
= single_set (temp
)) != 0
1082 && (temp5
= SET_DEST (temp1
),
1083 (GET_CODE (temp5
) == REG
1084 || (GET_CODE (temp5
) == SUBREG
1085 && (temp5
= SUBREG_REG (temp5
),
1086 GET_CODE (temp5
) == REG
))))
1087 && REGNO (temp5
) >= FIRST_PSEUDO_REGISTER
1088 && REGNO_FIRST_UID (REGNO (temp5
)) == INSN_UID (temp
)
1089 && REGNO_LAST_UID (REGNO (temp5
)) == INSN_UID (temp3
)
1090 && ! side_effects_p (SET_SRC (temp1
))
1091 && ! may_trap_p (SET_SRC (temp1
))
1092 && rtx_cost (SET_SRC (temp1
), SET
) < 10
1093 && (temp4
= single_set (temp3
)) != 0
1094 && (temp2
= SET_DEST (temp4
), GET_CODE (temp2
) == REG
)
1095 && GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
1096 #ifdef SMALL_REGISTER_CLASSES
1097 && (! SMALL_REGISTER_CLASSES
1098 || REGNO (temp2
) >= FIRST_PSEUDO_REGISTER
)
1100 && rtx_equal_p (SET_DEST (temp4
), temp2
)
1101 && ! side_effects_p (SET_SRC (temp4
))
1102 && ! may_trap_p (SET_SRC (temp4
))
1103 && rtx_cost (SET_SRC (temp4
), SET
) < 10)
1105 rtx
new = gen_reg_rtx (GET_MODE (temp2
));
1107 if (validate_change (temp3
, &SET_DEST (temp4
), new, 0))
1109 next
= emit_insn_after (gen_move_insn (temp2
, new), insn
);
1110 emit_insn_after_with_line_notes (PATTERN (temp
),
1111 PREV_INSN (insn
), temp
);
1112 emit_insn_after_with_line_notes (PATTERN (temp3
),
1113 PREV_INSN (insn
), temp3
);
1115 delete_insn (temp3
);
1116 reallabelprev
= prev_active_insn (JUMP_LABEL (insn
));
1119 #endif /* HAVE_cc0 */
1121 /* Try to use a conditional move (if the target has them), or a
1122 store-flag insn. The general case is:
1124 1) x = a; if (...) x = b; and
1127 If the jump would be faster, the machine should not have defined
1128 the movcc or scc insns!. These cases are often made by the
1129 previous optimization.
1131 The second case is treated as x = x; if (...) x = b;.
1133 INSN here is the jump around the store. We set:
1135 TEMP to the "x = b;" insn.
1138 TEMP3 to A (X in the second case).
1139 TEMP4 to the condition being tested.
1140 TEMP5 to the earliest insn used to find the condition. */
1142 if (/* We can't do this after reload has completed. */
1144 && this_is_condjump
&& ! this_is_simplejump
1145 /* Set TEMP to the "x = b;" insn. */
1146 && (temp
= next_nonnote_insn (insn
)) != 0
1147 && GET_CODE (temp
) == INSN
1148 && GET_CODE (PATTERN (temp
)) == SET
1149 && GET_CODE (temp1
= SET_DEST (PATTERN (temp
))) == REG
1150 #ifdef SMALL_REGISTER_CLASSES
1151 && (! SMALL_REGISTER_CLASSES
1152 || REGNO (temp1
) >= FIRST_PSEUDO_REGISTER
)
1154 && (GET_CODE (temp2
= SET_SRC (PATTERN (temp
))) == REG
1155 || GET_CODE (temp2
) == SUBREG
1156 /* ??? How about floating point constants? */
1157 || GET_CODE (temp2
) == CONST_INT
)
1158 /* Allow either form, but prefer the former if both apply.
1159 There is no point in using the old value of TEMP1 if
1160 it is a register, since cse will alias them. It can
1161 lose if the old value were a hard register since CSE
1162 won't replace hard registers. */
1163 && (((temp3
= reg_set_last (temp1
, insn
)) != 0)
1164 /* Make the latter case look like x = x; if (...) x = b; */
1165 || (temp3
= temp1
, 1))
1166 /* INSN must either branch to the insn after TEMP or the insn
1167 after TEMP must branch to the same place as INSN. */
1168 && (reallabelprev
== temp
1169 || ((temp4
= next_active_insn (temp
)) != 0
1170 && simplejump_p (temp4
)
1171 && JUMP_LABEL (temp4
) == JUMP_LABEL (insn
)))
1172 && (temp4
= get_condition (insn
, &temp5
)) != 0
1173 /* We must be comparing objects whose modes imply the size.
1174 We could handle BLKmode if (1) emit_store_flag could
1175 and (2) we could find the size reliably. */
1176 && GET_MODE (XEXP (temp4
, 0)) != BLKmode
1177 /* Even if branches are cheap, the store_flag optimization
1178 can win when the operation to be performed can be
1179 expressed directly. */
1181 /* If the previous insn sets CC0 and something else, we can't
1182 do this since we are going to delete that insn. */
1184 && ! ((temp6
= prev_nonnote_insn (insn
)) != 0
1185 && GET_CODE (temp6
) == INSN
1186 && (sets_cc0_p (PATTERN (temp6
)) == -1
1187 || (sets_cc0_p (PATTERN (temp6
)) == 1
1188 && FIND_REG_INC_NOTE (temp6
, NULL_RTX
))))
1192 #ifdef HAVE_conditional_move
1193 /* First try a conditional move. */
1195 enum rtx_code code
= GET_CODE (temp4
);
1197 rtx cond0
, cond1
, aval
, bval
;
1200 /* Copy the compared variables into cond0 and cond1, so that
1201 any side effects performed in or after the old comparison,
1202 will not affect our compare which will come later. */
1203 /* ??? Is it possible to just use the comparison in the jump
1204 insn? After all, we're going to delete it. We'd have
1205 to modify emit_conditional_move to take a comparison rtx
1206 instead or write a new function. */
1207 cond0
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 0)));
1208 /* We want the target to be able to simplify comparisons with
1209 zero (and maybe other constants as well), so don't create
1210 pseudos for them. There's no need to either. */
1211 if (GET_CODE (XEXP (temp4
, 1)) == CONST_INT
1212 || GET_CODE (XEXP (temp4
, 1)) == CONST_DOUBLE
)
1213 cond1
= XEXP (temp4
, 1);
1215 cond1
= gen_reg_rtx (GET_MODE (XEXP (temp4
, 1)));
1221 target
= emit_conditional_move (var
, code
,
1222 cond0
, cond1
, VOIDmode
,
1223 aval
, bval
, GET_MODE (var
),
1224 (code
== LTU
|| code
== GEU
1225 || code
== LEU
|| code
== GTU
));
1231 /* Save the conditional move sequence but don't emit it
1232 yet. On some machines, like the alpha, it is possible
1233 that temp5 == insn, so next generate the sequence that
1234 saves the compared values and then emit both
1235 sequences ensuring seq1 occurs before seq2. */
1236 seq2
= get_insns ();
1239 /* Now that we can't fail, generate the copy insns that
1240 preserve the compared values. */
1242 emit_move_insn (cond0
, XEXP (temp4
, 0));
1243 if (cond1
!= XEXP (temp4
, 1))
1244 emit_move_insn (cond1
, XEXP (temp4
, 1));
1245 seq1
= get_insns ();
1248 emit_insns_before (seq1
, temp5
);
1249 /* Insert conditional move after insn, to be sure that
1250 the jump and a possible compare won't be separated */
1251 emit_insns_after (seq2
, insn
);
1253 /* ??? We can also delete the insn that sets X to A.
1254 Flow will do it too though. */
1256 next
= NEXT_INSN (insn
);
1266 /* That didn't work, try a store-flag insn.
1268 We further divide the cases into:
1270 1) x = a; if (...) x = b; and either A or B is zero,
1271 2) if (...) x = 0; and jumps are expensive,
1272 3) x = a; if (...) x = b; and A and B are constants where all
1273 the set bits in A are also set in B and jumps are expensive,
1274 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1276 5) if (...) x = b; if jumps are even more expensive. */
1278 if (GET_MODE_CLASS (GET_MODE (temp1
)) == MODE_INT
1279 && ((GET_CODE (temp3
) == CONST_INT
)
1280 /* Make the latter case look like
1281 x = x; if (...) x = 0; */
1284 && temp2
== const0_rtx
)
1285 || BRANCH_COST
>= 3)))
1286 /* If B is zero, OK; if A is zero, can only do (1) if we
1287 can reverse the condition. See if (3) applies possibly
1288 by reversing the condition. Prefer reversing to (4) when
1289 branches are very expensive. */
1290 && (((BRANCH_COST
>= 2
1291 || STORE_FLAG_VALUE
== -1
1292 || (STORE_FLAG_VALUE
== 1
1293 /* Check that the mask is a power of two,
1294 so that it can probably be generated
1296 && exact_log2 (INTVAL (temp3
)) >= 0))
1297 && (reversep
= 0, temp2
== const0_rtx
))
1298 || ((BRANCH_COST
>= 2
1299 || STORE_FLAG_VALUE
== -1
1300 || (STORE_FLAG_VALUE
== 1
1301 && exact_log2 (INTVAL (temp2
)) >= 0))
1302 && temp3
== const0_rtx
1303 && (reversep
= can_reverse_comparison_p (temp4
, insn
)))
1304 || (BRANCH_COST
>= 2
1305 && GET_CODE (temp2
) == CONST_INT
1306 && GET_CODE (temp3
) == CONST_INT
1307 && ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp2
)
1308 || ((INTVAL (temp2
) & INTVAL (temp3
)) == INTVAL (temp3
)
1309 && (reversep
= can_reverse_comparison_p (temp4
,
1311 || BRANCH_COST
>= 3)
1314 enum rtx_code code
= GET_CODE (temp4
);
1315 rtx uval
, cval
, var
= temp1
;
1319 /* If necessary, reverse the condition. */
1321 code
= reverse_condition (code
), uval
= temp2
, cval
= temp3
;
1323 uval
= temp3
, cval
= temp2
;
1325 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1326 is the constant 1, it is best to just compute the result
1327 directly. If UVAL is constant and STORE_FLAG_VALUE
1328 includes all of its bits, it is best to compute the flag
1329 value unnormalized and `and' it with UVAL. Otherwise,
1330 normalize to -1 and `and' with UVAL. */
1331 normalizep
= (cval
!= const0_rtx
? -1
1332 : (uval
== const1_rtx
? 1
1333 : (GET_CODE (uval
) == CONST_INT
1334 && (INTVAL (uval
) & ~STORE_FLAG_VALUE
) == 0)
1337 /* We will be putting the store-flag insn immediately in
1338 front of the comparison that was originally being done,
1339 so we know all the variables in TEMP4 will be valid.
1340 However, this might be in front of the assignment of
1341 A to VAR. If it is, it would clobber the store-flag
1342 we will be emitting.
1344 Therefore, emit into a temporary which will be copied to
1345 VAR immediately after TEMP. */
1348 target
= emit_store_flag (gen_reg_rtx (GET_MODE (var
)), code
,
1349 XEXP (temp4
, 0), XEXP (temp4
, 1),
1351 (code
== LTU
|| code
== LEU
1352 || code
== GEU
|| code
== GTU
),
1362 /* Put the store-flag insns in front of the first insn
1363 used to compute the condition to ensure that we
1364 use the same values of them as the current
1365 comparison. However, the remainder of the insns we
1366 generate will be placed directly in front of the
1367 jump insn, in case any of the pseudos we use
1368 are modified earlier. */
1370 emit_insns_before (seq
, temp5
);
1374 /* Both CVAL and UVAL are non-zero. */
1375 if (cval
!= const0_rtx
&& uval
!= const0_rtx
)
1379 tem1
= expand_and (uval
, target
, NULL_RTX
);
1380 if (GET_CODE (cval
) == CONST_INT
1381 && GET_CODE (uval
) == CONST_INT
1382 && (INTVAL (cval
) & INTVAL (uval
)) == INTVAL (cval
))
1386 tem2
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1387 target
, NULL_RTX
, 0);
1388 tem2
= expand_and (cval
, tem2
,
1389 (GET_CODE (tem2
) == REG
1393 /* If we usually make new pseudos, do so here. This
1394 turns out to help machines that have conditional
1396 /* ??? Conditional moves have already been handled.
1397 This may be obsolete. */
1399 if (flag_expensive_optimizations
)
1402 target
= expand_binop (GET_MODE (var
), ior_optab
,
1406 else if (normalizep
!= 1)
1408 /* We know that either CVAL or UVAL is zero. If
1409 UVAL is zero, negate TARGET and `and' with CVAL.
1410 Otherwise, `and' with UVAL. */
1411 if (uval
== const0_rtx
)
1413 target
= expand_unop (GET_MODE (var
), one_cmpl_optab
,
1414 target
, NULL_RTX
, 0);
1418 target
= expand_and (uval
, target
,
1419 (GET_CODE (target
) == REG
1420 && ! preserve_subexpressions_p ()
1421 ? target
: NULL_RTX
));
1424 emit_move_insn (var
, target
);
1428 /* If INSN uses CC0, we must not separate it from the
1429 insn that sets cc0. */
1430 if (reg_mentioned_p (cc0_rtx
, PATTERN (before
)))
1431 before
= prev_nonnote_insn (before
);
1433 emit_insns_before (seq
, before
);
1436 next
= NEXT_INSN (insn
);
1446 /* If branches are expensive, convert
1447 if (foo) bar++; to bar += (foo != 0);
1448 and similarly for "bar--;"
1450 INSN is the conditional branch around the arithmetic. We set:
1452 TEMP is the arithmetic insn.
1453 TEMP1 is the SET doing the arithmetic.
1454 TEMP2 is the operand being incremented or decremented.
1455 TEMP3 to the condition being tested.
1456 TEMP4 to the earliest insn used to find the condition. */
1458 if ((BRANCH_COST
>= 2
1466 && ! reload_completed
1467 && this_is_condjump
&& ! this_is_simplejump
1468 && (temp
= next_nonnote_insn (insn
)) != 0
1469 && (temp1
= single_set (temp
)) != 0
1470 && (temp2
= SET_DEST (temp1
),
1471 GET_MODE_CLASS (GET_MODE (temp2
)) == MODE_INT
)
1472 && GET_CODE (SET_SRC (temp1
)) == PLUS
1473 && (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1474 || XEXP (SET_SRC (temp1
), 1) == constm1_rtx
)
1475 && rtx_equal_p (temp2
, XEXP (SET_SRC (temp1
), 0))
1476 && ! side_effects_p (temp2
)
1477 && ! may_trap_p (temp2
)
1478 /* INSN must either branch to the insn after TEMP or the insn
1479 after TEMP must branch to the same place as INSN. */
1480 && (reallabelprev
== temp
1481 || ((temp3
= next_active_insn (temp
)) != 0
1482 && simplejump_p (temp3
)
1483 && JUMP_LABEL (temp3
) == JUMP_LABEL (insn
)))
1484 && (temp3
= get_condition (insn
, &temp4
)) != 0
1485 /* We must be comparing objects whose modes imply the size.
1486 We could handle BLKmode if (1) emit_store_flag could
1487 and (2) we could find the size reliably. */
1488 && GET_MODE (XEXP (temp3
, 0)) != BLKmode
1489 && can_reverse_comparison_p (temp3
, insn
))
1491 rtx temp6
, target
= 0, seq
, init_insn
= 0, init
= temp2
;
1492 enum rtx_code code
= reverse_condition (GET_CODE (temp3
));
1496 /* It must be the case that TEMP2 is not modified in the range
1497 [TEMP4, INSN). The one exception we make is if the insn
1498 before INSN sets TEMP2 to something which is also unchanged
1499 in that range. In that case, we can move the initialization
1500 into our sequence. */
1502 if ((temp5
= prev_active_insn (insn
)) != 0
1503 && no_labels_between_p (temp5
, insn
)
1504 && GET_CODE (temp5
) == INSN
1505 && (temp6
= single_set (temp5
)) != 0
1506 && rtx_equal_p (temp2
, SET_DEST (temp6
))
1507 && (CONSTANT_P (SET_SRC (temp6
))
1508 || GET_CODE (SET_SRC (temp6
)) == REG
1509 || GET_CODE (SET_SRC (temp6
)) == SUBREG
))
1511 emit_insn (PATTERN (temp5
));
1513 init
= SET_SRC (temp6
);
1516 if (CONSTANT_P (init
)
1517 || ! reg_set_between_p (init
, PREV_INSN (temp4
), insn
))
1518 target
= emit_store_flag (gen_reg_rtx (GET_MODE (temp2
)), code
,
1519 XEXP (temp3
, 0), XEXP (temp3
, 1),
1521 (code
== LTU
|| code
== LEU
1522 || code
== GTU
|| code
== GEU
), 1);
1524 /* If we can do the store-flag, do the addition or
1528 target
= expand_binop (GET_MODE (temp2
),
1529 (XEXP (SET_SRC (temp1
), 1) == const1_rtx
1530 ? add_optab
: sub_optab
),
1531 temp2
, target
, temp2
, 0, OPTAB_WIDEN
);
1535 /* Put the result back in temp2 in case it isn't already.
1536 Then replace the jump, possible a CC0-setting insn in
1537 front of the jump, and TEMP, with the sequence we have
1540 if (target
!= temp2
)
1541 emit_move_insn (temp2
, target
);
1546 emit_insns_before (seq
, temp4
);
1550 delete_insn (init_insn
);
1552 next
= NEXT_INSN (insn
);
1554 delete_insn (prev_nonnote_insn (insn
));
1564 /* Simplify if (...) x = 1; else {...} if (x) ...
1565 We recognize this case scanning backwards as well.
1567 TEMP is the assignment to x;
1568 TEMP1 is the label at the head of the second if. */
1569 /* ?? This should call get_condition to find the values being
1570 compared, instead of looking for a COMPARE insn when HAVE_cc0
1571 is not defined. This would allow it to work on the m88k. */
1572 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1573 is not defined and the condition is tested by a separate compare
1574 insn. This is because the code below assumes that the result
1575 of the compare dies in the following branch.
1577 Not only that, but there might be other insns between the
1578 compare and branch whose results are live. Those insns need
1581 A way to fix this is to move the insns at JUMP_LABEL (insn)
1582 to before INSN. If we are running before flow, they will
1583 be deleted if they aren't needed. But this doesn't work
1586 This is really a special-case of jump threading, anyway. The
1587 right thing to do is to replace this and jump threading with
1588 much simpler code in cse.
1590 This code has been turned off in the non-cc0 case in the
1594 else if (this_is_simplejump
1595 /* Safe to skip USE and CLOBBER insns here
1596 since they will not be deleted. */
1597 && (temp
= prev_active_insn (insn
))
1598 && no_labels_between_p (temp
, insn
)
1599 && GET_CODE (temp
) == INSN
1600 && GET_CODE (PATTERN (temp
)) == SET
1601 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1602 && CONSTANT_P (SET_SRC (PATTERN (temp
)))
1603 && (temp1
= next_active_insn (JUMP_LABEL (insn
)))
1604 /* If we find that the next value tested is `x'
1605 (TEMP1 is the insn where this happens), win. */
1606 && GET_CODE (temp1
) == INSN
1607 && GET_CODE (PATTERN (temp1
)) == SET
1609 /* Does temp1 `tst' the value of x? */
1610 && SET_SRC (PATTERN (temp1
)) == SET_DEST (PATTERN (temp
))
1611 && SET_DEST (PATTERN (temp1
)) == cc0_rtx
1612 && (temp1
= next_nonnote_insn (temp1
))
1614 /* Does temp1 compare the value of x against zero? */
1615 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1616 && XEXP (SET_SRC (PATTERN (temp1
)), 1) == const0_rtx
1617 && (XEXP (SET_SRC (PATTERN (temp1
)), 0)
1618 == SET_DEST (PATTERN (temp
)))
1619 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1620 && (temp1
= find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1622 && condjump_p (temp1
))
1624 /* Get the if_then_else from the condjump. */
1625 rtx choice
= SET_SRC (PATTERN (temp1
));
1626 if (GET_CODE (choice
) == IF_THEN_ELSE
)
1628 enum rtx_code code
= GET_CODE (XEXP (choice
, 0));
1629 rtx val
= SET_SRC (PATTERN (temp
));
1631 = simplify_relational_operation (code
, GET_MODE (SET_DEST (PATTERN (temp
))),
1635 if (cond
== const_true_rtx
)
1636 ultimate
= XEXP (choice
, 1);
1637 else if (cond
== const0_rtx
)
1638 ultimate
= XEXP (choice
, 2);
1642 if (ultimate
== pc_rtx
)
1643 ultimate
= get_label_after (temp1
);
1644 else if (ultimate
&& GET_CODE (ultimate
) != RETURN
)
1645 ultimate
= XEXP (ultimate
, 0);
1647 if (ultimate
&& JUMP_LABEL(insn
) != ultimate
)
1648 changed
|= redirect_jump (insn
, ultimate
);
1654 /* @@ This needs a bit of work before it will be right.
1656 Any type of comparison can be accepted for the first and
1657 second compare. When rewriting the first jump, we must
1658 compute the what conditions can reach label3, and use the
1659 appropriate code. We can not simply reverse/swap the code
1660 of the first jump. In some cases, the second jump must be
1664 < == converts to > ==
1665 < != converts to == >
1668 If the code is written to only accept an '==' test for the second
1669 compare, then all that needs to be done is to swap the condition
1670 of the first branch.
1672 It is questionable whether we want this optimization anyways,
1673 since if the user wrote code like this because he/she knew that
1674 the jump to label1 is taken most of the time, then rewriting
1675 this gives slower code. */
1676 /* @@ This should call get_condition to find the values being
1677 compared, instead of looking for a COMPARE insn when HAVE_cc0
1678 is not defined. This would allow it to work on the m88k. */
1679 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1680 is not defined and the condition is tested by a separate compare
1681 insn. This is because the code below assumes that the result
1682 of the compare dies in the following branch. */
1684 /* Simplify test a ~= b
1698 where ~= is an inequality, e.g. >, and ~~= is the swapped
1701 We recognize this case scanning backwards.
1703 TEMP is the conditional jump to `label2';
1704 TEMP1 is the test for `a == b';
1705 TEMP2 is the conditional jump to `label1';
1706 TEMP3 is the test for `a ~= b'. */
1707 else if (this_is_simplejump
1708 && (temp
= prev_active_insn (insn
))
1709 && no_labels_between_p (temp
, insn
)
1710 && condjump_p (temp
)
1711 && (temp1
= prev_active_insn (temp
))
1712 && no_labels_between_p (temp1
, temp
)
1713 && GET_CODE (temp1
) == INSN
1714 && GET_CODE (PATTERN (temp1
)) == SET
1716 && sets_cc0_p (PATTERN (temp1
)) == 1
1718 && GET_CODE (SET_SRC (PATTERN (temp1
))) == COMPARE
1719 && GET_CODE (SET_DEST (PATTERN (temp1
))) == REG
1720 && (temp
== find_next_ref (SET_DEST (PATTERN (temp1
)), temp1
))
1722 && (temp2
= prev_active_insn (temp1
))
1723 && no_labels_between_p (temp2
, temp1
)
1724 && condjump_p (temp2
)
1725 && JUMP_LABEL (temp2
) == next_nonnote_insn (NEXT_INSN (insn
))
1726 && (temp3
= prev_active_insn (temp2
))
1727 && no_labels_between_p (temp3
, temp2
)
1728 && GET_CODE (PATTERN (temp3
)) == SET
1729 && rtx_equal_p (SET_DEST (PATTERN (temp3
)),
1730 SET_DEST (PATTERN (temp1
)))
1731 && rtx_equal_p (SET_SRC (PATTERN (temp1
)),
1732 SET_SRC (PATTERN (temp3
)))
1733 && ! inequality_comparisons_p (PATTERN (temp
))
1734 && inequality_comparisons_p (PATTERN (temp2
)))
1736 rtx fallthrough_label
= JUMP_LABEL (temp2
);
1738 ++LABEL_NUSES (fallthrough_label
);
1739 if (swap_jump (temp2
, JUMP_LABEL (insn
)))
1745 if (--LABEL_NUSES (fallthrough_label
) == 0)
1746 delete_insn (fallthrough_label
);
1749 /* Simplify if (...) {... x = 1;} if (x) ...
1751 We recognize this case backwards.
1753 TEMP is the test of `x';
1754 TEMP1 is the assignment to `x' at the end of the
1755 previous statement. */
1756 /* @@ This should call get_condition to find the values being
1757 compared, instead of looking for a COMPARE insn when HAVE_cc0
1758 is not defined. This would allow it to work on the m88k. */
1759 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1760 is not defined and the condition is tested by a separate compare
1761 insn. This is because the code below assumes that the result
1762 of the compare dies in the following branch. */
1764 /* ??? This has to be turned off. The problem is that the
1765 unconditional jump might indirectly end up branching to the
1766 label between TEMP1 and TEMP. We can't detect this, in general,
1767 since it may become a jump to there after further optimizations.
1768 If that jump is done, it will be deleted, so we will retry
1769 this optimization in the next pass, thus an infinite loop.
1771 The present code prevents this by putting the jump after the
1772 label, but this is not logically correct. */
1774 else if (this_is_condjump
1775 /* Safe to skip USE and CLOBBER insns here
1776 since they will not be deleted. */
1777 && (temp
= prev_active_insn (insn
))
1778 && no_labels_between_p (temp
, insn
)
1779 && GET_CODE (temp
) == INSN
1780 && GET_CODE (PATTERN (temp
)) == SET
1782 && sets_cc0_p (PATTERN (temp
)) == 1
1783 && GET_CODE (SET_SRC (PATTERN (temp
))) == REG
1785 /* Temp must be a compare insn, we can not accept a register
1786 to register move here, since it may not be simply a
1788 && GET_CODE (SET_SRC (PATTERN (temp
))) == COMPARE
1789 && XEXP (SET_SRC (PATTERN (temp
)), 1) == const0_rtx
1790 && GET_CODE (XEXP (SET_SRC (PATTERN (temp
)), 0)) == REG
1791 && GET_CODE (SET_DEST (PATTERN (temp
))) == REG
1792 && insn
== find_next_ref (SET_DEST (PATTERN (temp
)), temp
)
1794 /* May skip USE or CLOBBER insns here
1795 for checking for opportunity, since we
1796 take care of them later. */
1797 && (temp1
= prev_active_insn (temp
))
1798 && GET_CODE (temp1
) == INSN
1799 && GET_CODE (PATTERN (temp1
)) == SET
1801 && SET_SRC (PATTERN (temp
)) == SET_DEST (PATTERN (temp1
))
1803 && (XEXP (SET_SRC (PATTERN (temp
)), 0)
1804 == SET_DEST (PATTERN (temp1
)))
1806 && CONSTANT_P (SET_SRC (PATTERN (temp1
)))
1807 /* If this isn't true, cse will do the job. */
1808 && ! no_labels_between_p (temp1
, temp
))
1810 /* Get the if_then_else from the condjump. */
1811 rtx choice
= SET_SRC (PATTERN (insn
));
1812 if (GET_CODE (choice
) == IF_THEN_ELSE
1813 && (GET_CODE (XEXP (choice
, 0)) == EQ
1814 || GET_CODE (XEXP (choice
, 0)) == NE
))
1816 int want_nonzero
= (GET_CODE (XEXP (choice
, 0)) == NE
);
1821 /* Get the place that condjump will jump to
1822 if it is reached from here. */
1823 if ((SET_SRC (PATTERN (temp1
)) != const0_rtx
)
1825 ultimate
= XEXP (choice
, 1);
1827 ultimate
= XEXP (choice
, 2);
1828 /* Get it as a CODE_LABEL. */
1829 if (ultimate
== pc_rtx
)
1830 ultimate
= get_label_after (insn
);
1832 /* Get the label out of the LABEL_REF. */
1833 ultimate
= XEXP (ultimate
, 0);
1835 /* Insert the jump immediately before TEMP, specifically
1836 after the label that is between TEMP1 and TEMP. */
1837 last_insn
= PREV_INSN (temp
);
1839 /* If we would be branching to the next insn, the jump
1840 would immediately be deleted and the re-inserted in
1841 a subsequent pass over the code. So don't do anything
1843 if (next_active_insn (last_insn
)
1844 != next_active_insn (ultimate
))
1846 emit_barrier_after (last_insn
);
1847 p
= emit_jump_insn_after (gen_jump (ultimate
),
1849 JUMP_LABEL (p
) = ultimate
;
1850 ++LABEL_NUSES (ultimate
);
1851 if (INSN_UID (ultimate
) < max_jump_chain
1852 && INSN_CODE (p
) < max_jump_chain
)
1854 jump_chain
[INSN_UID (p
)]
1855 = jump_chain
[INSN_UID (ultimate
)];
1856 jump_chain
[INSN_UID (ultimate
)] = p
;
1864 /* Detect a conditional jump going to the same place
1865 as an immediately following unconditional jump. */
1866 else if (this_is_condjump
1867 && (temp
= next_active_insn (insn
)) != 0
1868 && simplejump_p (temp
)
1869 && (next_active_insn (JUMP_LABEL (insn
))
1870 == next_active_insn (JUMP_LABEL (temp
))))
1874 /* ??? Optional. Disables some optimizations, but makes
1875 gcov output more accurate with -O. */
1876 if (flag_test_coverage
&& !reload_completed
)
1877 for (tem
= insn
; tem
!= temp
; tem
= NEXT_INSN (tem
))
1878 if (GET_CODE (tem
) == NOTE
&& NOTE_LINE_NUMBER (tem
) > 0)
1888 /* Detect a conditional jump jumping over an unconditional jump. */
1890 else if ((this_is_condjump
|| this_is_condjump_in_parallel
)
1891 && ! this_is_simplejump
1892 && reallabelprev
!= 0
1893 && GET_CODE (reallabelprev
) == JUMP_INSN
1894 && prev_active_insn (reallabelprev
) == insn
1895 && no_labels_between_p (insn
, reallabelprev
)
1896 && simplejump_p (reallabelprev
))
1898 /* When we invert the unconditional jump, we will be
1899 decrementing the usage count of its old label.
1900 Make sure that we don't delete it now because that
1901 might cause the following code to be deleted. */
1902 rtx prev_uses
= prev_nonnote_insn (reallabelprev
);
1903 rtx prev_label
= JUMP_LABEL (insn
);
1906 ++LABEL_NUSES (prev_label
);
1908 if (invert_jump (insn
, JUMP_LABEL (reallabelprev
)))
1910 /* It is very likely that if there are USE insns before
1911 this jump, they hold REG_DEAD notes. These REG_DEAD
1912 notes are no longer valid due to this optimization,
1913 and will cause the life-analysis that following passes
1914 (notably delayed-branch scheduling) to think that
1915 these registers are dead when they are not.
1917 To prevent this trouble, we just remove the USE insns
1918 from the insn chain. */
1920 while (prev_uses
&& GET_CODE (prev_uses
) == INSN
1921 && GET_CODE (PATTERN (prev_uses
)) == USE
)
1923 rtx useless
= prev_uses
;
1924 prev_uses
= prev_nonnote_insn (prev_uses
);
1925 delete_insn (useless
);
1928 delete_insn (reallabelprev
);
1933 /* We can now safely delete the label if it is unreferenced
1934 since the delete_insn above has deleted the BARRIER. */
1935 if (prev_label
&& --LABEL_NUSES (prev_label
) == 0)
1936 delete_insn (prev_label
);
1941 /* Detect a jump to a jump. */
1943 nlabel
= follow_jumps (JUMP_LABEL (insn
));
1944 if (nlabel
!= JUMP_LABEL (insn
)
1945 && redirect_jump (insn
, nlabel
))
1951 /* Look for if (foo) bar; else break; */
1952 /* The insns look like this:
1953 insn = condjump label1;
1954 ...range1 (some insns)...
1957 ...range2 (some insns)...
1958 jump somewhere unconditionally
1961 rtx label1
= next_label (insn
);
1962 rtx range1end
= label1
? prev_active_insn (label1
) : 0;
1963 /* Don't do this optimization on the first round, so that
1964 jump-around-a-jump gets simplified before we ask here
1965 whether a jump is unconditional.
1967 Also don't do it when we are called after reload since
1968 it will confuse reorg. */
1970 && (reload_completed
? ! flag_delayed_branch
: 1)
1971 /* Make sure INSN is something we can invert. */
1972 && condjump_p (insn
)
1974 && JUMP_LABEL (insn
) == label1
1975 && LABEL_NUSES (label1
) == 1
1976 && GET_CODE (range1end
) == JUMP_INSN
1977 && simplejump_p (range1end
))
1979 rtx label2
= next_label (label1
);
1980 rtx range2end
= label2
? prev_active_insn (label2
) : 0;
1981 if (range1end
!= range2end
1982 && JUMP_LABEL (range1end
) == label2
1983 && GET_CODE (range2end
) == JUMP_INSN
1984 && GET_CODE (NEXT_INSN (range2end
)) == BARRIER
1985 /* Invert the jump condition, so we
1986 still execute the same insns in each case. */
1987 && invert_jump (insn
, label1
))
1989 rtx range1beg
= next_active_insn (insn
);
1990 rtx range2beg
= next_active_insn (label1
);
1991 rtx range1after
, range2after
;
1992 rtx range1before
, range2before
;
1995 /* Include in each range any notes before it, to be
1996 sure that we get the line number note if any, even
1997 if there are other notes here. */
1998 while (PREV_INSN (range1beg
)
1999 && GET_CODE (PREV_INSN (range1beg
)) == NOTE
)
2000 range1beg
= PREV_INSN (range1beg
);
2002 while (PREV_INSN (range2beg
)
2003 && GET_CODE (PREV_INSN (range2beg
)) == NOTE
)
2004 range2beg
= PREV_INSN (range2beg
);
2006 /* Don't move NOTEs for blocks or loops; shift them
2007 outside the ranges, where they'll stay put. */
2008 range1beg
= squeeze_notes (range1beg
, range1end
);
2009 range2beg
= squeeze_notes (range2beg
, range2end
);
2011 /* Get current surrounds of the 2 ranges. */
2012 range1before
= PREV_INSN (range1beg
);
2013 range2before
= PREV_INSN (range2beg
);
2014 range1after
= NEXT_INSN (range1end
);
2015 range2after
= NEXT_INSN (range2end
);
2017 /* Splice range2 where range1 was. */
2018 NEXT_INSN (range1before
) = range2beg
;
2019 PREV_INSN (range2beg
) = range1before
;
2020 NEXT_INSN (range2end
) = range1after
;
2021 PREV_INSN (range1after
) = range2end
;
2022 /* Splice range1 where range2 was. */
2023 NEXT_INSN (range2before
) = range1beg
;
2024 PREV_INSN (range1beg
) = range2before
;
2025 NEXT_INSN (range1end
) = range2after
;
2026 PREV_INSN (range2after
) = range1end
;
2028 /* Check for a loop end note between the end of
2029 range2, and the next code label. If there is one,
2030 then what we have really seen is
2031 if (foo) break; end_of_loop;
2032 and moved the break sequence outside the loop.
2033 We must move the LOOP_END note to where the
2034 loop really ends now, or we will confuse loop
2035 optimization. Stop if we find a LOOP_BEG note
2036 first, since we don't want to move the LOOP_END
2037 note in that case. */
2038 for (;range2after
!= label2
; range2after
= rangenext
)
2040 rangenext
= NEXT_INSN (range2after
);
2041 if (GET_CODE (range2after
) == NOTE
)
2043 if (NOTE_LINE_NUMBER (range2after
)
2044 == NOTE_INSN_LOOP_END
)
2046 NEXT_INSN (PREV_INSN (range2after
))
2048 PREV_INSN (rangenext
)
2049 = PREV_INSN (range2after
);
2050 PREV_INSN (range2after
)
2051 = PREV_INSN (range1beg
);
2052 NEXT_INSN (range2after
) = range1beg
;
2053 NEXT_INSN (PREV_INSN (range1beg
))
2055 PREV_INSN (range1beg
) = range2after
;
2057 else if (NOTE_LINE_NUMBER (range2after
)
2058 == NOTE_INSN_LOOP_BEG
)
2068 /* Now that the jump has been tensioned,
2069 try cross jumping: check for identical code
2070 before the jump and before its target label. */
2072 /* First, cross jumping of conditional jumps: */
2074 if (cross_jump
&& condjump_p (insn
))
2076 rtx newjpos
, newlpos
;
2077 rtx x
= prev_real_insn (JUMP_LABEL (insn
));
2079 /* A conditional jump may be crossjumped
2080 only if the place it jumps to follows
2081 an opposing jump that comes back here. */
2083 if (x
!= 0 && ! jump_back_p (x
, insn
))
2084 /* We have no opposing jump;
2085 cannot cross jump this insn. */
2089 /* TARGET is nonzero if it is ok to cross jump
2090 to code before TARGET. If so, see if matches. */
2092 find_cross_jump (insn
, x
, 2,
2093 &newjpos
, &newlpos
);
2097 do_cross_jump (insn
, newjpos
, newlpos
);
2098 /* Make the old conditional jump
2099 into an unconditional one. */
2100 SET_SRC (PATTERN (insn
))
2101 = gen_rtx (LABEL_REF
, VOIDmode
, JUMP_LABEL (insn
));
2102 INSN_CODE (insn
) = -1;
2103 emit_barrier_after (insn
);
2104 /* Add to jump_chain unless this is a new label
2105 whose UID is too large. */
2106 if (INSN_UID (JUMP_LABEL (insn
)) < max_jump_chain
)
2108 jump_chain
[INSN_UID (insn
)]
2109 = jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2110 jump_chain
[INSN_UID (JUMP_LABEL (insn
))] = insn
;
2117 /* Cross jumping of unconditional jumps:
2118 a few differences. */
2120 if (cross_jump
&& simplejump_p (insn
))
2122 rtx newjpos
, newlpos
;
2127 /* TARGET is nonzero if it is ok to cross jump
2128 to code before TARGET. If so, see if matches. */
2129 find_cross_jump (insn
, JUMP_LABEL (insn
), 1,
2130 &newjpos
, &newlpos
);
2132 /* If cannot cross jump to code before the label,
2133 see if we can cross jump to another jump to
2135 /* Try each other jump to this label. */
2136 if (INSN_UID (JUMP_LABEL (insn
)) < max_uid
)
2137 for (target
= jump_chain
[INSN_UID (JUMP_LABEL (insn
))];
2138 target
!= 0 && newjpos
== 0;
2139 target
= jump_chain
[INSN_UID (target
)])
2141 && JUMP_LABEL (target
) == JUMP_LABEL (insn
)
2142 /* Ignore TARGET if it's deleted. */
2143 && ! INSN_DELETED_P (target
))
2144 find_cross_jump (insn
, target
, 2,
2145 &newjpos
, &newlpos
);
2149 do_cross_jump (insn
, newjpos
, newlpos
);
2155 /* This code was dead in the previous jump.c! */
2156 if (cross_jump
&& GET_CODE (PATTERN (insn
)) == RETURN
)
2158 /* Return insns all "jump to the same place"
2159 so we can cross-jump between any two of them. */
2161 rtx newjpos
, newlpos
, target
;
2165 /* If cannot cross jump to code before the label,
2166 see if we can cross jump to another jump to
2168 /* Try each other jump to this label. */
2169 for (target
= jump_chain
[0];
2170 target
!= 0 && newjpos
== 0;
2171 target
= jump_chain
[INSN_UID (target
)])
2173 && ! INSN_DELETED_P (target
)
2174 && GET_CODE (PATTERN (target
)) == RETURN
)
2175 find_cross_jump (insn
, target
, 2,
2176 &newjpos
, &newlpos
);
2180 do_cross_jump (insn
, newjpos
, newlpos
);
2191 /* Delete extraneous line number notes.
2192 Note that two consecutive notes for different lines are not really
2193 extraneous. There should be some indication where that line belonged,
2194 even if it became empty. */
2199 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
2200 if (GET_CODE (insn
) == NOTE
&& NOTE_LINE_NUMBER (insn
) >= 0)
2202 /* Delete this note if it is identical to previous note. */
2204 && NOTE_SOURCE_FILE (insn
) == NOTE_SOURCE_FILE (last_note
)
2205 && NOTE_LINE_NUMBER (insn
) == NOTE_LINE_NUMBER (last_note
))
2218 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2219 in front of it. If the machine allows it at this point (we might be
2220 after reload for a leaf routine), it will improve optimization for it
2221 to be there. We do this both here and at the start of this pass since
2222 the RETURN might have been deleted by some of our optimizations. */
2223 insn
= get_last_insn ();
2224 while (insn
&& GET_CODE (insn
) == NOTE
)
2225 insn
= PREV_INSN (insn
);
2227 if (insn
&& GET_CODE (insn
) != BARRIER
)
2229 emit_jump_insn (gen_return ());
2235 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2236 If so, delete it, and record that this function can drop off the end. */
2242 /* One label can follow the end-note: the return label. */
2243 && ((GET_CODE (insn
) == CODE_LABEL
&& n_labels
-- > 0)
2244 /* Ordinary insns can follow it if returning a structure. */
2245 || GET_CODE (insn
) == INSN
2246 /* If machine uses explicit RETURN insns, no epilogue,
2247 then one of them follows the note. */
2248 || (GET_CODE (insn
) == JUMP_INSN
2249 && GET_CODE (PATTERN (insn
)) == RETURN
)
2250 /* A barrier can follow the return insn. */
2251 || GET_CODE (insn
) == BARRIER
2252 /* Other kinds of notes can follow also. */
2253 || (GET_CODE (insn
) == NOTE
2254 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_FUNCTION_END
)))
2255 insn
= PREV_INSN (insn
);
2258 /* Report if control can fall through at the end of the function. */
2259 if (insn
&& GET_CODE (insn
) == NOTE
2260 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_FUNCTION_END
)
2266 /* Show JUMP_CHAIN no longer valid. */
2270 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2271 jump. Assume that this unconditional jump is to the exit test code. If
2272 the code is sufficiently simple, make a copy of it before INSN,
2273 followed by a jump to the exit of the loop. Then delete the unconditional
2276 Return 1 if we made the change, else 0.
2278 This is only safe immediately after a regscan pass because it uses the
2279 values of regno_first_uid and regno_last_uid. */
2282 duplicate_loop_exit_test (loop_start
)
2285 rtx insn
, set
, reg
, p
, link
;
2288 rtx exitcode
= NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start
)));
2290 int max_reg
= max_reg_num ();
2293 /* Scan the exit code. We do not perform this optimization if any insn:
2297 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2298 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2299 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2302 Also, don't do this if the exit code is more than 20 insns. */
2304 for (insn
= exitcode
;
2306 && ! (GET_CODE (insn
) == NOTE
2307 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
);
2308 insn
= NEXT_INSN (insn
))
2310 switch (GET_CODE (insn
))
2316 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2317 a jump immediately after the loop start that branches outside
2318 the loop but within an outer loop, near the exit test.
2319 If we copied this exit test and created a phony
2320 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2321 before the exit test look like these could be safely moved
2322 out of the loop even if they actually may be never executed.
2323 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2325 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
2326 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
2327 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
2328 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
2333 if (++num_insns
> 20
2334 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
2335 || find_reg_note (insn
, REG_LIBCALL
, NULL_RTX
))
2341 /* Unless INSN is zero, we can do the optimization. */
2347 /* See if any insn sets a register only used in the loop exit code and
2348 not a user variable. If so, replace it with a new register. */
2349 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2350 if (GET_CODE (insn
) == INSN
2351 && (set
= single_set (insn
)) != 0
2352 && ((reg
= SET_DEST (set
), GET_CODE (reg
) == REG
)
2353 || (GET_CODE (reg
) == SUBREG
2354 && (reg
= SUBREG_REG (reg
), GET_CODE (reg
) == REG
)))
2355 && REGNO (reg
) >= FIRST_PSEUDO_REGISTER
2356 && REGNO_FIRST_UID (REGNO (reg
)) == INSN_UID (insn
))
2358 for (p
= NEXT_INSN (insn
); p
!= lastexit
; p
= NEXT_INSN (p
))
2359 if (REGNO_LAST_UID (REGNO (reg
)) == INSN_UID (p
))
2364 /* We can do the replacement. Allocate reg_map if this is the
2365 first replacement we found. */
2368 reg_map
= (rtx
*) alloca (max_reg
* sizeof (rtx
));
2369 bzero ((char *) reg_map
, max_reg
* sizeof (rtx
));
2372 REG_LOOP_TEST_P (reg
) = 1;
2374 reg_map
[REGNO (reg
)] = gen_reg_rtx (GET_MODE (reg
));
2378 /* Now copy each insn. */
2379 for (insn
= exitcode
; insn
!= lastexit
; insn
= NEXT_INSN (insn
))
2380 switch (GET_CODE (insn
))
2383 copy
= emit_barrier_before (loop_start
);
2386 /* Only copy line-number notes. */
2387 if (NOTE_LINE_NUMBER (insn
) >= 0)
2389 copy
= emit_note_before (NOTE_LINE_NUMBER (insn
), loop_start
);
2390 NOTE_SOURCE_FILE (copy
) = NOTE_SOURCE_FILE (insn
);
2395 copy
= emit_insn_before (copy_rtx (PATTERN (insn
)), loop_start
);
2397 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2399 mark_jump_label (PATTERN (copy
), copy
, 0);
2401 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2403 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
2404 if (REG_NOTE_KIND (link
) != REG_LABEL
)
2406 = copy_rtx (gen_rtx (EXPR_LIST
, REG_NOTE_KIND (link
),
2407 XEXP (link
, 0), REG_NOTES (copy
)));
2408 if (reg_map
&& REG_NOTES (copy
))
2409 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2413 copy
= emit_jump_insn_before (copy_rtx (PATTERN (insn
)), loop_start
);
2415 replace_regs (PATTERN (copy
), reg_map
, max_reg
, 1);
2416 mark_jump_label (PATTERN (copy
), copy
, 0);
2417 if (REG_NOTES (insn
))
2419 REG_NOTES (copy
) = copy_rtx (REG_NOTES (insn
));
2421 replace_regs (REG_NOTES (copy
), reg_map
, max_reg
, 1);
2424 /* If this is a simple jump, add it to the jump chain. */
2426 if (INSN_UID (copy
) < max_jump_chain
&& JUMP_LABEL (copy
)
2427 && simplejump_p (copy
))
2429 jump_chain
[INSN_UID (copy
)]
2430 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2431 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2439 /* Now clean up by emitting a jump to the end label and deleting the jump
2440 at the start of the loop. */
2441 if (! copy
|| GET_CODE (copy
) != BARRIER
)
2443 copy
= emit_jump_insn_before (gen_jump (get_label_after (insn
)),
2445 mark_jump_label (PATTERN (copy
), copy
, 0);
2446 if (INSN_UID (copy
) < max_jump_chain
2447 && INSN_UID (JUMP_LABEL (copy
)) < max_jump_chain
)
2449 jump_chain
[INSN_UID (copy
)]
2450 = jump_chain
[INSN_UID (JUMP_LABEL (copy
))];
2451 jump_chain
[INSN_UID (JUMP_LABEL (copy
))] = copy
;
2453 emit_barrier_before (loop_start
);
2456 /* Mark the exit code as the virtual top of the converted loop. */
2457 emit_note_before (NOTE_INSN_LOOP_VTOP
, exitcode
);
2459 delete_insn (next_nonnote_insn (loop_start
));
2464 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2465 loop-end notes between START and END out before START. Assume that
2466 END is not such a note. START may be such a note. Returns the value
2467 of the new starting insn, which may be different if the original start
2471 squeeze_notes (start
, end
)
2477 for (insn
= start
; insn
!= end
; insn
= next
)
2479 next
= NEXT_INSN (insn
);
2480 if (GET_CODE (insn
) == NOTE
2481 && (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_END
2482 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BLOCK_BEG
2483 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
2484 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
2485 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
2486 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_VTOP
))
2492 rtx prev
= PREV_INSN (insn
);
2493 PREV_INSN (insn
) = PREV_INSN (start
);
2494 NEXT_INSN (insn
) = start
;
2495 NEXT_INSN (PREV_INSN (insn
)) = insn
;
2496 PREV_INSN (NEXT_INSN (insn
)) = insn
;
2497 NEXT_INSN (prev
) = next
;
2498 PREV_INSN (next
) = prev
;
2506 /* Compare the instructions before insn E1 with those before E2
2507 to find an opportunity for cross jumping.
2508 (This means detecting identical sequences of insns followed by
2509 jumps to the same place, or followed by a label and a jump
2510 to that label, and replacing one with a jump to the other.)
2512 Assume E1 is a jump that jumps to label E2
2513 (that is not always true but it might as well be).
2514 Find the longest possible equivalent sequences
2515 and store the first insns of those sequences into *F1 and *F2.
2516 Store zero there if no equivalent preceding instructions are found.
2518 We give up if we find a label in stream 1.
2519 Actually we could transfer that label into stream 2. */
2522 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
2527 register rtx i1
= e1
, i2
= e2
;
2528 register rtx p1
, p2
;
2531 rtx last1
= 0, last2
= 0;
2532 rtx afterlast1
= 0, afterlast2
= 0;
2540 i1
= prev_nonnote_insn (i1
);
2542 i2
= PREV_INSN (i2
);
2543 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
2544 i2
= PREV_INSN (i2
);
2549 /* Don't allow the range of insns preceding E1 or E2
2550 to include the other (E2 or E1). */
2551 if (i2
== e1
|| i1
== e2
)
2554 /* If we will get to this code by jumping, those jumps will be
2555 tensioned to go directly to the new label (before I2),
2556 so this cross-jumping won't cost extra. So reduce the minimum. */
2557 if (GET_CODE (i1
) == CODE_LABEL
)
2563 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
2569 /* If this is a CALL_INSN, compare register usage information.
2570 If we don't check this on stack register machines, the two
2571 CALL_INSNs might be merged leaving reg-stack.c with mismatching
2572 numbers of stack registers in the same basic block.
2573 If we don't check this on machines with delay slots, a delay slot may
2574 be filled that clobbers a parameter expected by the subroutine.
2576 ??? We take the simple route for now and assume that if they're
2577 equal, they were constructed identically. */
2579 if (GET_CODE (i1
) == CALL_INSN
2580 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
2581 CALL_INSN_FUNCTION_USAGE (i2
)))
2585 /* If cross_jump_death_matters is not 0, the insn's mode
2586 indicates whether or not the insn contains any stack-like
2589 if (!lose
&& cross_jump_death_matters
&& GET_MODE (i1
) == QImode
)
2591 /* If register stack conversion has already been done, then
2592 death notes must also be compared before it is certain that
2593 the two instruction streams match. */
2596 HARD_REG_SET i1_regset
, i2_regset
;
2598 CLEAR_HARD_REG_SET (i1_regset
);
2599 CLEAR_HARD_REG_SET (i2_regset
);
2601 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
2602 if (REG_NOTE_KIND (note
) == REG_DEAD
2603 && STACK_REG_P (XEXP (note
, 0)))
2604 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
2606 for (note
= REG_NOTES (i2
); note
; note
= XEXP (note
, 1))
2607 if (REG_NOTE_KIND (note
) == REG_DEAD
2608 && STACK_REG_P (XEXP (note
, 0)))
2609 SET_HARD_REG_BIT (i2_regset
, REGNO (XEXP (note
, 0)));
2611 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
2620 /* Don't allow old-style asm or volatile extended asms to be accepted
2621 for cross jumping purposes. It is conceptually correct to allow
2622 them, since cross-jumping preserves the dynamic instruction order
2623 even though it is changing the static instruction order. However,
2624 if an asm is being used to emit an assembler pseudo-op, such as
2625 the MIPS `.set reorder' pseudo-op, then the static instruction order
2626 matters and it must be preserved. */
2627 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
2628 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
2629 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
2632 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
2633 || ! rtx_renumbered_equal_p (p1
, p2
))
2635 /* The following code helps take care of G++ cleanups. */
2639 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
2640 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
2641 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
2642 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
2643 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
2644 /* If the equivalences are not to a constant, they may
2645 reference pseudos that no longer exist, so we can't
2647 && CONSTANT_P (XEXP (equiv1
, 0))
2648 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
2650 rtx s1
= single_set (i1
);
2651 rtx s2
= single_set (i2
);
2652 if (s1
!= 0 && s2
!= 0
2653 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
2655 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
2656 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
2657 if (! rtx_renumbered_equal_p (p1
, p2
))
2659 else if (apply_change_group ())
2664 /* Insns fail to match; cross jumping is limited to the following
2668 /* Don't allow the insn after a compare to be shared by
2669 cross-jumping unless the compare is also shared.
2670 Here, if either of these non-matching insns is a compare,
2671 exclude the following insn from possible cross-jumping. */
2672 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
2673 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
2676 /* If cross-jumping here will feed a jump-around-jump
2677 optimization, this jump won't cost extra, so reduce
2679 if (GET_CODE (i1
) == JUMP_INSN
2681 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
2687 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
2689 /* Ok, this insn is potentially includable in a cross-jump here. */
2690 afterlast1
= last1
, afterlast2
= last2
;
2691 last1
= i1
, last2
= i2
, --minimum
;
2695 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
2696 *f1
= last1
, *f2
= last2
;
2700 do_cross_jump (insn
, newjpos
, newlpos
)
2701 rtx insn
, newjpos
, newlpos
;
2703 /* Find an existing label at this point
2704 or make a new one if there is none. */
2705 register rtx label
= get_label_before (newlpos
);
2707 /* Make the same jump insn jump to the new point. */
2708 if (GET_CODE (PATTERN (insn
)) == RETURN
)
2710 /* Remove from jump chain of returns. */
2711 delete_from_jump_chain (insn
);
2712 /* Change the insn. */
2713 PATTERN (insn
) = gen_jump (label
);
2714 INSN_CODE (insn
) = -1;
2715 JUMP_LABEL (insn
) = label
;
2716 LABEL_NUSES (label
)++;
2717 /* Add to new the jump chain. */
2718 if (INSN_UID (label
) < max_jump_chain
2719 && INSN_UID (insn
) < max_jump_chain
)
2721 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
2722 jump_chain
[INSN_UID (label
)] = insn
;
2726 redirect_jump (insn
, label
);
2728 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
2729 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
2730 the NEWJPOS stream. */
2732 while (newjpos
!= insn
)
2736 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
2737 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
2738 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
2739 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
2740 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
2741 remove_note (newlpos
, lnote
);
2743 delete_insn (newjpos
);
2744 newjpos
= next_real_insn (newjpos
);
2745 newlpos
= next_real_insn (newlpos
);
2749 /* Return the label before INSN, or put a new label there. */
2752 get_label_before (insn
)
2757 /* Find an existing label at this point
2758 or make a new one if there is none. */
2759 label
= prev_nonnote_insn (insn
);
2761 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
2763 rtx prev
= PREV_INSN (insn
);
2765 label
= gen_label_rtx ();
2766 emit_label_after (label
, prev
);
2767 LABEL_NUSES (label
) = 0;
2772 /* Return the label after INSN, or put a new label there. */
2775 get_label_after (insn
)
2780 /* Find an existing label at this point
2781 or make a new one if there is none. */
2782 label
= next_nonnote_insn (insn
);
2784 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
2786 label
= gen_label_rtx ();
2787 emit_label_after (label
, insn
);
2788 LABEL_NUSES (label
) = 0;
2793 /* Return 1 if INSN is a jump that jumps to right after TARGET
2794 only on the condition that TARGET itself would drop through.
2795 Assumes that TARGET is a conditional jump. */
2798 jump_back_p (insn
, target
)
2802 enum rtx_code codei
, codet
;
2804 if (simplejump_p (insn
) || ! condjump_p (insn
)
2805 || simplejump_p (target
)
2806 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
2809 cinsn
= XEXP (SET_SRC (PATTERN (insn
)), 0);
2810 ctarget
= XEXP (SET_SRC (PATTERN (target
)), 0);
2812 codei
= GET_CODE (cinsn
);
2813 codet
= GET_CODE (ctarget
);
2815 if (XEXP (SET_SRC (PATTERN (insn
)), 1) == pc_rtx
)
2817 if (! can_reverse_comparison_p (cinsn
, insn
))
2819 codei
= reverse_condition (codei
);
2822 if (XEXP (SET_SRC (PATTERN (target
)), 2) == pc_rtx
)
2824 if (! can_reverse_comparison_p (ctarget
, target
))
2826 codet
= reverse_condition (codet
);
2829 return (codei
== codet
2830 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
2831 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
2834 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
2835 return non-zero if it is safe to reverse this comparison. It is if our
2836 floating-point is not IEEE, if this is an NE or EQ comparison, or if
2837 this is known to be an integer comparison. */
2840 can_reverse_comparison_p (comparison
, insn
)
2846 /* If this is not actually a comparison, we can't reverse it. */
2847 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
2850 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
2851 /* If this is an NE comparison, it is safe to reverse it to an EQ
2852 comparison and vice versa, even for floating point. If no operands
2853 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
2854 always false and NE is always true, so the reversal is also valid. */
2856 || GET_CODE (comparison
) == NE
2857 || GET_CODE (comparison
) == EQ
)
2860 arg0
= XEXP (comparison
, 0);
2862 /* Make sure ARG0 is one of the actual objects being compared. If we
2863 can't do this, we can't be sure the comparison can be reversed.
2865 Handle cc0 and a MODE_CC register. */
2866 if ((GET_CODE (arg0
) == REG
&& GET_MODE_CLASS (GET_MODE (arg0
)) == MODE_CC
)
2872 rtx prev
= prev_nonnote_insn (insn
);
2873 rtx set
= single_set (prev
);
2875 if (set
== 0 || SET_DEST (set
) != arg0
)
2878 arg0
= SET_SRC (set
);
2880 if (GET_CODE (arg0
) == COMPARE
)
2881 arg0
= XEXP (arg0
, 0);
2884 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
2885 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
2886 return (GET_CODE (arg0
) == CONST_INT
2887 || (GET_MODE (arg0
) != VOIDmode
2888 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_CC
2889 && GET_MODE_CLASS (GET_MODE (arg0
)) != MODE_FLOAT
));
2892 /* Given an rtx-code for a comparison, return the code
2893 for the negated comparison.
2894 WATCH OUT! reverse_condition is not safe to use on a jump
2895 that might be acting on the results of an IEEE floating point comparison,
2896 because of the special treatment of non-signaling nans in comparisons.
2897 Use can_reverse_comparison_p to be sure. */
2900 reverse_condition (code
)
2941 /* Similar, but return the code when two operands of a comparison are swapped.
2942 This IS safe for IEEE floating-point. */
2945 swap_condition (code
)
2984 /* Given a comparison CODE, return the corresponding unsigned comparison.
2985 If CODE is an equality comparison or already an unsigned comparison,
2986 CODE is returned. */
2989 unsigned_condition (code
)
3019 /* Similarly, return the signed version of a comparison. */
3022 signed_condition (code
)
3052 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3053 truth of CODE1 implies the truth of CODE2. */
3056 comparison_dominates_p (code1
, code2
)
3057 enum rtx_code code1
, code2
;
3065 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
)
3070 if (code2
== LE
|| code2
== NE
)
3075 if (code2
== GE
|| code2
== NE
)
3080 if (code2
== LEU
|| code2
== NE
)
3085 if (code2
== GEU
|| code2
== NE
)
3093 /* Return 1 if INSN is an unconditional jump and nothing else. */
3099 return (GET_CODE (insn
) == JUMP_INSN
3100 && GET_CODE (PATTERN (insn
)) == SET
3101 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
3102 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
3105 /* Return nonzero if INSN is a (possibly) conditional jump
3106 and nothing more. */
3112 register rtx x
= PATTERN (insn
);
3113 if (GET_CODE (x
) != SET
)
3115 if (GET_CODE (SET_DEST (x
)) != PC
)
3117 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
3119 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
3121 if (XEXP (SET_SRC (x
), 2) == pc_rtx
3122 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
3123 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
3125 if (XEXP (SET_SRC (x
), 1) == pc_rtx
3126 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
3127 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
3132 /* Return nonzero if INSN is a (possibly) conditional jump
3133 and nothing more. */
3136 condjump_in_parallel_p (insn
)
3139 register rtx x
= PATTERN (insn
);
3141 if (GET_CODE (x
) != PARALLEL
)
3144 x
= XVECEXP (x
, 0, 0);
3146 if (GET_CODE (x
) != SET
)
3148 if (GET_CODE (SET_DEST (x
)) != PC
)
3150 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
3152 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
3154 if (XEXP (SET_SRC (x
), 2) == pc_rtx
3155 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
3156 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
3158 if (XEXP (SET_SRC (x
), 1) == pc_rtx
3159 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
3160 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
3165 /* Return 1 if X is an RTX that does nothing but set the condition codes
3166 and CLOBBER or USE registers.
3167 Return -1 if X does explicitly set the condition codes,
3168 but also does other things. */
3175 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
3177 if (GET_CODE (x
) == PARALLEL
)
3181 int other_things
= 0;
3182 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
3184 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
3185 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
3187 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
3190 return ! sets_cc0
? 0 : other_things
? -1 : 1;
3198 /* Follow any unconditional jump at LABEL;
3199 return the ultimate label reached by any such chain of jumps.
3200 If LABEL is not followed by a jump, return LABEL.
3201 If the chain loops or we can't find end, return LABEL,
3202 since that tells caller to avoid changing the insn.
3204 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3205 a USE or CLOBBER. */
3208 follow_jumps (label
)
3213 register rtx value
= label
;
3218 && (insn
= next_active_insn (value
)) != 0
3219 && GET_CODE (insn
) == JUMP_INSN
3220 && ((JUMP_LABEL (insn
) != 0 && simplejump_p (insn
))
3221 || GET_CODE (PATTERN (insn
)) == RETURN
)
3222 && (next
= NEXT_INSN (insn
))
3223 && GET_CODE (next
) == BARRIER
);
3226 /* Don't chain through the insn that jumps into a loop
3227 from outside the loop,
3228 since that would create multiple loop entry jumps
3229 and prevent loop optimization. */
3231 if (!reload_completed
)
3232 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
3233 if (GET_CODE (tem
) == NOTE
3234 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
3235 /* ??? Optional. Disables some optimizations, but makes
3236 gcov output more accurate with -O. */
3237 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
3240 /* If we have found a cycle, make the insn jump to itself. */
3241 if (JUMP_LABEL (insn
) == label
)
3244 tem
= next_active_insn (JUMP_LABEL (insn
));
3245 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
3246 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
3249 value
= JUMP_LABEL (insn
);
3256 /* Assuming that field IDX of X is a vector of label_refs,
3257 replace each of them by the ultimate label reached by it.
3258 Return nonzero if a change is made.
3259 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3262 tension_vector_labels (x
, idx
)
3268 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
3270 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
3271 register rtx nlabel
= follow_jumps (olabel
);
3272 if (nlabel
&& nlabel
!= olabel
)
3274 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
3275 ++LABEL_NUSES (nlabel
);
3276 if (--LABEL_NUSES (olabel
) == 0)
3277 delete_insn (olabel
);
3284 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3285 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3286 in INSN, then store one of them in JUMP_LABEL (INSN).
3287 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3288 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3289 Also, when there are consecutive labels, canonicalize on the last of them.
3291 Note that two labels separated by a loop-beginning note
3292 must be kept distinct if we have not yet done loop-optimization,
3293 because the gap between them is where loop-optimize
3294 will want to move invariant code to. CROSS_JUMP tells us
3295 that loop-optimization is done with.
3297 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3298 two labels distinct if they are separated by only USE or CLOBBER insns. */
3301 mark_jump_label (x
, insn
, cross_jump
)
3306 register RTX_CODE code
= GET_CODE (x
);
3324 /* If this is a constant-pool reference, see if it is a label. */
3325 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
3326 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
3327 mark_jump_label (get_pool_constant (XEXP (x
, 0)), insn
, cross_jump
);
3332 rtx label
= XEXP (x
, 0);
3337 if (GET_CODE (label
) != CODE_LABEL
)
3340 /* Ignore references to labels of containing functions. */
3341 if (LABEL_REF_NONLOCAL_P (x
))
3344 /* If there are other labels following this one,
3345 replace it with the last of the consecutive labels. */
3346 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
3348 if (GET_CODE (next
) == CODE_LABEL
)
3350 else if (cross_jump
&& GET_CODE (next
) == INSN
3351 && (GET_CODE (PATTERN (next
)) == USE
3352 || GET_CODE (PATTERN (next
)) == CLOBBER
))
3354 else if (GET_CODE (next
) != NOTE
)
3356 else if (! cross_jump
3357 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
3358 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
3359 /* ??? Optional. Disables some optimizations, but
3360 makes gcov output more accurate with -O. */
3361 || (flag_test_coverage
&& NOTE_LINE_NUMBER (next
) > 0)))
3365 XEXP (x
, 0) = label
;
3366 ++LABEL_NUSES (label
);
3370 if (GET_CODE (insn
) == JUMP_INSN
)
3371 JUMP_LABEL (insn
) = label
;
3373 /* If we've changed OLABEL and we had a REG_LABEL note
3374 for it, update it as well. */
3375 else if (label
!= olabel
3376 && (note
= find_reg_note (insn
, REG_LABEL
, olabel
)) != 0)
3377 XEXP (note
, 0) = label
;
3379 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3381 else if (! find_reg_note (insn
, REG_LABEL
, label
))
3383 rtx next
= next_real_insn (label
);
3384 /* Don't record labels that refer to dispatch tables.
3385 This is not necessary, since the tablejump
3386 references the same label.
3387 And if we did record them, flow.c would make worse code. */
3389 || ! (GET_CODE (next
) == JUMP_INSN
3390 && (GET_CODE (PATTERN (next
)) == ADDR_VEC
3391 || GET_CODE (PATTERN (next
)) == ADDR_DIFF_VEC
)))
3392 REG_NOTES (insn
) = gen_rtx (EXPR_LIST
, REG_LABEL
, label
,
3399 /* Do walk the labels in a vector, but not the first operand of an
3400 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
3404 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
3406 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
3407 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
, cross_jump
);
3412 fmt
= GET_RTX_FORMAT (code
);
3413 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3416 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
);
3417 else if (fmt
[i
] == 'E')
3420 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3421 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
);
3426 /* If all INSN does is set the pc, delete it,
3427 and delete the insn that set the condition codes for it
3428 if that's what the previous thing was. */
3434 register rtx set
= single_set (insn
);
3436 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
3437 delete_computation (insn
);
3440 /* Delete INSN and recursively delete insns that compute values used only
3441 by INSN. This uses the REG_DEAD notes computed during flow analysis.
3442 If we are running before flow.c, we need do nothing since flow.c will
3443 delete dead code. We also can't know if the registers being used are
3444 dead or not at this point.
3446 Otherwise, look at all our REG_DEAD notes. If a previous insn does
3447 nothing other than set a register that dies in this insn, we can delete
3450 On machines with CC0, if CC0 is used in this insn, we may be able to
3451 delete the insn that set it. */
3454 delete_computation (insn
)
3460 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
3462 rtx prev
= prev_nonnote_insn (insn
);
3463 /* We assume that at this stage
3464 CC's are always set explicitly
3465 and always immediately before the jump that
3466 will use them. So if the previous insn
3467 exists to set the CC's, delete it
3468 (unless it performs auto-increments, etc.). */
3469 if (prev
&& GET_CODE (prev
) == INSN
3470 && sets_cc0_p (PATTERN (prev
)))
3472 if (sets_cc0_p (PATTERN (prev
)) > 0
3473 && !FIND_REG_INC_NOTE (prev
, NULL_RTX
))
3474 delete_computation (prev
);
3476 /* Otherwise, show that cc0 won't be used. */
3477 REG_NOTES (prev
) = gen_rtx (EXPR_LIST
, REG_UNUSED
,
3478 cc0_rtx
, REG_NOTES (prev
));
3483 for (note
= REG_NOTES (insn
); note
; note
= next
)
3487 next
= XEXP (note
, 1);
3489 if (REG_NOTE_KIND (note
) != REG_DEAD
3490 /* Verify that the REG_NOTE is legitimate. */
3491 || GET_CODE (XEXP (note
, 0)) != REG
)
3494 for (our_prev
= prev_nonnote_insn (insn
);
3495 our_prev
&& GET_CODE (our_prev
) == INSN
;
3496 our_prev
= prev_nonnote_insn (our_prev
))
3498 /* If we reach a SEQUENCE, it is too complex to try to
3499 do anything with it, so give up. */
3500 if (GET_CODE (PATTERN (our_prev
)) == SEQUENCE
)
3503 if (GET_CODE (PATTERN (our_prev
)) == USE
3504 && GET_CODE (XEXP (PATTERN (our_prev
), 0)) == INSN
)
3505 /* reorg creates USEs that look like this. We leave them
3506 alone because reorg needs them for its own purposes. */
3509 if (reg_set_p (XEXP (note
, 0), PATTERN (our_prev
)))
3511 if (FIND_REG_INC_NOTE (our_prev
, NULL_RTX
))
3514 if (GET_CODE (PATTERN (our_prev
)) == PARALLEL
)
3516 /* If we find a SET of something else, we can't
3521 for (i
= 0; i
< XVECLEN (PATTERN (our_prev
), 0); i
++)
3523 rtx part
= XVECEXP (PATTERN (our_prev
), 0, i
);
3525 if (GET_CODE (part
) == SET
3526 && SET_DEST (part
) != XEXP (note
, 0))
3530 if (i
== XVECLEN (PATTERN (our_prev
), 0))
3531 delete_computation (our_prev
);
3533 else if (GET_CODE (PATTERN (our_prev
)) == SET
3534 && SET_DEST (PATTERN (our_prev
)) == XEXP (note
, 0))
3535 delete_computation (our_prev
);
3540 /* If OUR_PREV references the register that dies here, it is an
3541 additional use. Hence any prior SET isn't dead. However, this
3542 insn becomes the new place for the REG_DEAD note. */
3543 if (reg_overlap_mentioned_p (XEXP (note
, 0),
3544 PATTERN (our_prev
)))
3546 XEXP (note
, 1) = REG_NOTES (our_prev
);
3547 REG_NOTES (our_prev
) = note
;
3556 /* Delete insn INSN from the chain of insns and update label ref counts.
3557 May delete some following insns as a consequence; may even delete
3558 a label elsewhere and insns that follow it.
3560 Returns the first insn after INSN that was not deleted. */
3566 register rtx next
= NEXT_INSN (insn
);
3567 register rtx prev
= PREV_INSN (insn
);
3568 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
3569 register int dont_really_delete
= 0;
3571 while (next
&& INSN_DELETED_P (next
))
3572 next
= NEXT_INSN (next
);
3574 /* This insn is already deleted => return first following nondeleted. */
3575 if (INSN_DELETED_P (insn
))
3578 /* Don't delete user-declared labels. Convert them to special NOTEs
3580 if (was_code_label
&& LABEL_NAME (insn
) != 0
3581 && optimize
&& ! dont_really_delete
)
3583 PUT_CODE (insn
, NOTE
);
3584 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
3585 NOTE_SOURCE_FILE (insn
) = 0;
3586 dont_really_delete
= 1;
3589 /* Mark this insn as deleted. */
3590 INSN_DELETED_P (insn
) = 1;
3592 /* If this is an unconditional jump, delete it from the jump chain. */
3593 if (simplejump_p (insn
))
3594 delete_from_jump_chain (insn
);
3596 /* If instruction is followed by a barrier,
3597 delete the barrier too. */
3599 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
3601 INSN_DELETED_P (next
) = 1;
3602 next
= NEXT_INSN (next
);
3605 /* Patch out INSN (and the barrier if any) */
3607 if (optimize
&& ! dont_really_delete
)
3611 NEXT_INSN (prev
) = next
;
3612 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
3613 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
3614 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
3619 PREV_INSN (next
) = prev
;
3620 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
3621 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
3624 if (prev
&& NEXT_INSN (prev
) == 0)
3625 set_last_insn (prev
);
3628 /* If deleting a jump, decrement the count of the label,
3629 and delete the label if it is now unused. */
3631 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
3632 if (--LABEL_NUSES (JUMP_LABEL (insn
)) == 0)
3634 /* This can delete NEXT or PREV,
3635 either directly if NEXT is JUMP_LABEL (INSN),
3636 or indirectly through more levels of jumps. */
3637 delete_insn (JUMP_LABEL (insn
));
3638 /* I feel a little doubtful about this loop,
3639 but I see no clean and sure alternative way
3640 to find the first insn after INSN that is not now deleted.
3641 I hope this works. */
3642 while (next
&& INSN_DELETED_P (next
))
3643 next
= NEXT_INSN (next
);
3647 /* Likewise if we're deleting a dispatch table. */
3649 if (GET_CODE (insn
) == JUMP_INSN
3650 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
3651 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
3653 rtx pat
= PATTERN (insn
);
3654 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
3655 int len
= XVECLEN (pat
, diff_vec_p
);
3657 for (i
= 0; i
< len
; i
++)
3658 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
3659 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
3660 while (next
&& INSN_DELETED_P (next
))
3661 next
= NEXT_INSN (next
);
3665 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
3666 prev
= PREV_INSN (prev
);
3668 /* If INSN was a label and a dispatch table follows it,
3669 delete the dispatch table. The tablejump must have gone already.
3670 It isn't useful to fall through into a table. */
3673 && NEXT_INSN (insn
) != 0
3674 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
3675 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
3676 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
3677 next
= delete_insn (NEXT_INSN (insn
));
3679 /* If INSN was a label, delete insns following it if now unreachable. */
3681 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
3683 register RTX_CODE code
;
3685 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
3686 || code
== NOTE
|| code
== BARRIER
3687 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
3690 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
3691 next
= NEXT_INSN (next
);
3692 /* Keep going past other deleted labels to delete what follows. */
3693 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
3694 next
= NEXT_INSN (next
);
3696 /* Note: if this deletes a jump, it can cause more
3697 deletion of unreachable code, after a different label.
3698 As long as the value from this recursive call is correct,
3699 this invocation functions correctly. */
3700 next
= delete_insn (next
);
3707 /* Advance from INSN till reaching something not deleted
3708 then return that. May return INSN itself. */
3711 next_nondeleted_insn (insn
)
3714 while (INSN_DELETED_P (insn
))
3715 insn
= NEXT_INSN (insn
);
3719 /* Delete a range of insns from FROM to TO, inclusive.
3720 This is for the sake of peephole optimization, so assume
3721 that whatever these insns do will still be done by a new
3722 peephole insn that will replace them. */
3725 delete_for_peephole (from
, to
)
3726 register rtx from
, to
;
3728 register rtx insn
= from
;
3732 register rtx next
= NEXT_INSN (insn
);
3733 register rtx prev
= PREV_INSN (insn
);
3735 if (GET_CODE (insn
) != NOTE
)
3737 INSN_DELETED_P (insn
) = 1;
3739 /* Patch this insn out of the chain. */
3740 /* We don't do this all at once, because we
3741 must preserve all NOTEs. */
3743 NEXT_INSN (prev
) = next
;
3746 PREV_INSN (next
) = prev
;
3754 /* Note that if TO is an unconditional jump
3755 we *do not* delete the BARRIER that follows,
3756 since the peephole that replaces this sequence
3757 is also an unconditional jump in that case. */
3760 /* Invert the condition of the jump JUMP, and make it jump
3761 to label NLABEL instead of where it jumps now. */
3764 invert_jump (jump
, nlabel
)
3767 /* We have to either invert the condition and change the label or
3768 do neither. Either operation could fail. We first try to invert
3769 the jump. If that succeeds, we try changing the label. If that fails,
3770 we invert the jump back to what it was. */
3772 if (! invert_exp (PATTERN (jump
), jump
))
3775 if (redirect_jump (jump
, nlabel
))
3777 if (flag_branch_probabilities
)
3779 rtx note
= find_reg_note (jump
, REG_BR_PROB
, 0);
3781 /* An inverted jump means that a probability taken becomes a
3782 probability not taken. Subtract the branch probability from the
3783 probability base to convert it back to a taken probability.
3784 (We don't flip the probability on a branch that's never taken. */
3785 if (note
&& XINT (XEXP (note
, 0), 0) >= 0)
3786 XINT (XEXP (note
, 0), 0) = REG_BR_PROB_BASE
- XINT (XEXP (note
, 0), 0);
3792 if (! invert_exp (PATTERN (jump
), jump
))
3793 /* This should just be putting it back the way it was. */
3799 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3801 Return 1 if we can do so, 0 if we cannot find a way to do so that
3802 matches a pattern. */
3805 invert_exp (x
, insn
)
3809 register RTX_CODE code
;
3813 code
= GET_CODE (x
);
3815 if (code
== IF_THEN_ELSE
)
3817 register rtx comp
= XEXP (x
, 0);
3820 /* We can do this in two ways: The preferable way, which can only
3821 be done if this is not an integer comparison, is to reverse
3822 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3823 of the IF_THEN_ELSE. If we can't do either, fail. */
3825 if (can_reverse_comparison_p (comp
, insn
)
3826 && validate_change (insn
, &XEXP (x
, 0),
3827 gen_rtx (reverse_condition (GET_CODE (comp
)),
3828 GET_MODE (comp
), XEXP (comp
, 0),
3829 XEXP (comp
, 1)), 0))
3833 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
3834 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
3835 return apply_change_group ();
3838 fmt
= GET_RTX_FORMAT (code
);
3839 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3842 if (! invert_exp (XEXP (x
, i
), insn
))
3847 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3848 if (!invert_exp (XVECEXP (x
, i
, j
), insn
))
3856 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
3857 If the old jump target label is unused as a result,
3858 it and the code following it may be deleted.
3860 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3863 The return value will be 1 if the change was made, 0 if it wasn't (this
3864 can only occur for NLABEL == 0). */
3867 redirect_jump (jump
, nlabel
)
3870 register rtx olabel
= JUMP_LABEL (jump
);
3872 if (nlabel
== olabel
)
3875 if (! redirect_exp (&PATTERN (jump
), olabel
, nlabel
, jump
))
3878 /* If this is an unconditional branch, delete it from the jump_chain of
3879 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3880 have UID's in range and JUMP_CHAIN is valid). */
3881 if (jump_chain
&& (simplejump_p (jump
)
3882 || GET_CODE (PATTERN (jump
)) == RETURN
))
3884 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
3886 delete_from_jump_chain (jump
);
3887 if (label_index
< max_jump_chain
3888 && INSN_UID (jump
) < max_jump_chain
)
3890 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
3891 jump_chain
[label_index
] = jump
;
3895 JUMP_LABEL (jump
) = nlabel
;
3897 ++LABEL_NUSES (nlabel
);
3899 if (olabel
&& --LABEL_NUSES (olabel
) == 0)
3900 delete_insn (olabel
);
3905 /* Delete the instruction JUMP from any jump chain it might be on. */
3908 delete_from_jump_chain (jump
)
3912 rtx olabel
= JUMP_LABEL (jump
);
3914 /* Handle unconditional jumps. */
3915 if (jump_chain
&& olabel
!= 0
3916 && INSN_UID (olabel
) < max_jump_chain
3917 && simplejump_p (jump
))
3918 index
= INSN_UID (olabel
);
3919 /* Handle return insns. */
3920 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
3924 if (jump_chain
[index
] == jump
)
3925 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
3930 for (insn
= jump_chain
[index
];
3932 insn
= jump_chain
[INSN_UID (insn
)])
3933 if (jump_chain
[INSN_UID (insn
)] == jump
)
3935 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
3941 /* If NLABEL is nonzero, throughout the rtx at LOC,
3942 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
3943 zero, alter (RETURN) to (LABEL_REF NLABEL).
3945 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
3946 validity with validate_change. Convert (set (pc) (label_ref olabel))
3949 Return 0 if we found a change we would like to make but it is invalid.
3950 Otherwise, return 1. */
3953 redirect_exp (loc
, olabel
, nlabel
, insn
)
3958 register rtx x
= *loc
;
3959 register RTX_CODE code
= GET_CODE (x
);
3963 if (code
== LABEL_REF
)
3965 if (XEXP (x
, 0) == olabel
)
3968 XEXP (x
, 0) = nlabel
;
3970 return validate_change (insn
, loc
, gen_rtx (RETURN
, VOIDmode
), 0);
3974 else if (code
== RETURN
&& olabel
== 0)
3976 x
= gen_rtx (LABEL_REF
, VOIDmode
, nlabel
);
3977 if (loc
== &PATTERN (insn
))
3978 x
= gen_rtx (SET
, VOIDmode
, pc_rtx
, x
);
3979 return validate_change (insn
, loc
, x
, 0);
3982 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
3983 && GET_CODE (SET_SRC (x
)) == LABEL_REF
3984 && XEXP (SET_SRC (x
), 0) == olabel
)
3985 return validate_change (insn
, loc
, gen_rtx (RETURN
, VOIDmode
), 0);
3987 fmt
= GET_RTX_FORMAT (code
);
3988 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3991 if (! redirect_exp (&XEXP (x
, i
), olabel
, nlabel
, insn
))
3996 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3997 if (! redirect_exp (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
))
4005 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4007 If the old jump target label (before the dispatch table) becomes unused,
4008 it and the dispatch table may be deleted. In that case, find the insn
4009 before the jump references that label and delete it and logical successors
4013 redirect_tablejump (jump
, nlabel
)
4016 register rtx olabel
= JUMP_LABEL (jump
);
4018 /* Add this jump to the jump_chain of NLABEL. */
4019 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
4020 && INSN_UID (jump
) < max_jump_chain
)
4022 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
4023 jump_chain
[INSN_UID (nlabel
)] = jump
;
4026 PATTERN (jump
) = gen_jump (nlabel
);
4027 JUMP_LABEL (jump
) = nlabel
;
4028 ++LABEL_NUSES (nlabel
);
4029 INSN_CODE (jump
) = -1;
4031 if (--LABEL_NUSES (olabel
) == 0)
4033 delete_labelref_insn (jump
, olabel
, 0);
4034 delete_insn (olabel
);
4038 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4039 If we found one, delete it and then delete this insn if DELETE_THIS is
4040 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4043 delete_labelref_insn (insn
, label
, delete_this
)
4050 if (GET_CODE (insn
) != NOTE
4051 && reg_mentioned_p (label
, PATTERN (insn
)))
4062 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
4063 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
4077 /* Like rtx_equal_p except that it considers two REGs as equal
4078 if they renumber to the same value and considers two commutative
4079 operations to be the same if the order of the operands has been
4083 rtx_renumbered_equal_p (x
, y
)
4087 register RTX_CODE code
= GET_CODE (x
);
4093 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
4094 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
4095 && GET_CODE (SUBREG_REG (y
)) == REG
)))
4097 int reg_x
= -1, reg_y
= -1;
4098 int word_x
= 0, word_y
= 0;
4100 if (GET_MODE (x
) != GET_MODE (y
))
4103 /* If we haven't done any renumbering, don't
4104 make any assumptions. */
4105 if (reg_renumber
== 0)
4106 return rtx_equal_p (x
, y
);
4110 reg_x
= REGNO (SUBREG_REG (x
));
4111 word_x
= SUBREG_WORD (x
);
4113 if (reg_renumber
[reg_x
] >= 0)
4115 reg_x
= reg_renumber
[reg_x
] + word_x
;
4123 if (reg_renumber
[reg_x
] >= 0)
4124 reg_x
= reg_renumber
[reg_x
];
4127 if (GET_CODE (y
) == SUBREG
)
4129 reg_y
= REGNO (SUBREG_REG (y
));
4130 word_y
= SUBREG_WORD (y
);
4132 if (reg_renumber
[reg_y
] >= 0)
4134 reg_y
= reg_renumber
[reg_y
];
4142 if (reg_renumber
[reg_y
] >= 0)
4143 reg_y
= reg_renumber
[reg_y
];
4146 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
4149 /* Now we have disposed of all the cases
4150 in which different rtx codes can match. */
4151 if (code
!= GET_CODE (y
))
4163 return INTVAL (x
) == INTVAL (y
);
4166 /* We can't assume nonlocal labels have their following insns yet. */
4167 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
4168 return XEXP (x
, 0) == XEXP (y
, 0);
4170 /* Two label-refs are equivalent if they point at labels
4171 in the same position in the instruction stream. */
4172 return (next_real_insn (XEXP (x
, 0))
4173 == next_real_insn (XEXP (y
, 0)));
4176 return XSTR (x
, 0) == XSTR (y
, 0);
4179 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4181 if (GET_MODE (x
) != GET_MODE (y
))
4184 /* For commutative operations, the RTX match if the operand match in any
4185 order. Also handle the simple binary and unary cases without a loop. */
4186 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
4187 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
4188 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
4189 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
4190 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
4191 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
4192 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
4193 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
4194 else if (GET_RTX_CLASS (code
) == '1')
4195 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
4197 /* Compare the elements. If any pair of corresponding elements
4198 fail to match, return 0 for the whole things. */
4200 fmt
= GET_RTX_FORMAT (code
);
4201 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4207 if (XWINT (x
, i
) != XWINT (y
, i
))
4212 if (XINT (x
, i
) != XINT (y
, i
))
4217 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4222 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
4227 if (XEXP (x
, i
) != XEXP (y
, i
))
4234 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
4236 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
4237 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
4248 /* If X is a hard register or equivalent to one or a subregister of one,
4249 return the hard register number. If X is a pseudo register that was not
4250 assigned a hard register, return the pseudo register number. Otherwise,
4251 return -1. Any rtx is valid for X. */
4257 if (GET_CODE (x
) == REG
)
4259 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
4260 return reg_renumber
[REGNO (x
)];
4263 if (GET_CODE (x
) == SUBREG
)
4265 int base
= true_regnum (SUBREG_REG (x
));
4266 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
4267 return SUBREG_WORD (x
) + base
;
4272 /* Optimize code of the form:
4274 for (x = a[i]; x; ...)
4276 for (x = a[i]; x; ...)
4280 Loop optimize will change the above code into
4284 { ...; if (! (x = ...)) break; }
4287 { ...; if (! (x = ...)) break; }
4290 In general, if the first test fails, the program can branch
4291 directly to `foo' and skip the second try which is doomed to fail.
4292 We run this after loop optimization and before flow analysis. */
4294 /* When comparing the insn patterns, we track the fact that different
4295 pseudo-register numbers may have been used in each computation.
4296 The following array stores an equivalence -- same_regs[I] == J means
4297 that pseudo register I was used in the first set of tests in a context
4298 where J was used in the second set. We also count the number of such
4299 pending equivalences. If nonzero, the expressions really aren't the
4302 static int *same_regs
;
4304 static int num_same_regs
;
4306 /* Track any registers modified between the target of the first jump and
4307 the second jump. They never compare equal. */
4309 static char *modified_regs
;
4311 /* Record if memory was modified. */
4313 static int modified_mem
;
4315 /* Called via note_stores on each insn between the target of the first
4316 branch and the second branch. It marks any changed registers. */
4319 mark_modified_reg (dest
, x
)
4325 if (GET_CODE (dest
) == SUBREG
)
4326 dest
= SUBREG_REG (dest
);
4328 if (GET_CODE (dest
) == MEM
)
4331 if (GET_CODE (dest
) != REG
)
4334 regno
= REGNO (dest
);
4335 if (regno
>= FIRST_PSEUDO_REGISTER
)
4336 modified_regs
[regno
] = 1;
4338 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
4339 modified_regs
[regno
+ i
] = 1;
4342 /* F is the first insn in the chain of insns. */
4345 thread_jumps (f
, max_reg
, flag_before_loop
)
4348 int flag_before_loop
;
4350 /* Basic algorithm is to find a conditional branch,
4351 the label it may branch to, and the branch after
4352 that label. If the two branches test the same condition,
4353 walk back from both branch paths until the insn patterns
4354 differ, or code labels are hit. If we make it back to
4355 the target of the first branch, then we know that the first branch
4356 will either always succeed or always fail depending on the relative
4357 senses of the two branches. So adjust the first branch accordingly
4360 rtx label
, b1
, b2
, t1
, t2
;
4361 enum rtx_code code1
, code2
;
4362 rtx b1op0
, b1op1
, b2op0
, b2op1
;
4367 /* Allocate register tables and quick-reset table. */
4368 modified_regs
= (char *) alloca (max_reg
* sizeof (char));
4369 same_regs
= (int *) alloca (max_reg
* sizeof (int));
4370 all_reset
= (int *) alloca (max_reg
* sizeof (int));
4371 for (i
= 0; i
< max_reg
; i
++)
4378 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
4380 /* Get to a candidate branch insn. */
4381 if (GET_CODE (b1
) != JUMP_INSN
4382 || ! condjump_p (b1
) || simplejump_p (b1
)
4383 || JUMP_LABEL (b1
) == 0)
4386 bzero (modified_regs
, max_reg
* sizeof (char));
4389 bcopy ((char *) all_reset
, (char *) same_regs
,
4390 max_reg
* sizeof (int));
4393 label
= JUMP_LABEL (b1
);
4395 /* Look for a branch after the target. Record any registers and
4396 memory modified between the target and the branch. Stop when we
4397 get to a label since we can't know what was changed there. */
4398 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
4400 if (GET_CODE (b2
) == CODE_LABEL
)
4403 else if (GET_CODE (b2
) == JUMP_INSN
)
4405 /* If this is an unconditional jump and is the only use of
4406 its target label, we can follow it. */
4407 if (simplejump_p (b2
)
4408 && JUMP_LABEL (b2
) != 0
4409 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
4411 b2
= JUMP_LABEL (b2
);
4418 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
4421 if (GET_CODE (b2
) == CALL_INSN
)
4424 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4425 if (call_used_regs
[i
] && ! fixed_regs
[i
]
4426 && i
!= STACK_POINTER_REGNUM
4427 && i
!= FRAME_POINTER_REGNUM
4428 && i
!= HARD_FRAME_POINTER_REGNUM
4429 && i
!= ARG_POINTER_REGNUM
)
4430 modified_regs
[i
] = 1;
4433 note_stores (PATTERN (b2
), mark_modified_reg
);
4436 /* Check the next candidate branch insn from the label
4439 || GET_CODE (b2
) != JUMP_INSN
4441 || ! condjump_p (b2
)
4442 || simplejump_p (b2
))
4445 /* Get the comparison codes and operands, reversing the
4446 codes if appropriate. If we don't have comparison codes,
4447 we can't do anything. */
4448 b1op0
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 0);
4449 b1op1
= XEXP (XEXP (SET_SRC (PATTERN (b1
)), 0), 1);
4450 code1
= GET_CODE (XEXP (SET_SRC (PATTERN (b1
)), 0));
4451 if (XEXP (SET_SRC (PATTERN (b1
)), 1) == pc_rtx
)
4452 code1
= reverse_condition (code1
);
4454 b2op0
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 0);
4455 b2op1
= XEXP (XEXP (SET_SRC (PATTERN (b2
)), 0), 1);
4456 code2
= GET_CODE (XEXP (SET_SRC (PATTERN (b2
)), 0));
4457 if (XEXP (SET_SRC (PATTERN (b2
)), 1) == pc_rtx
)
4458 code2
= reverse_condition (code2
);
4460 /* If they test the same things and knowing that B1 branches
4461 tells us whether or not B2 branches, check if we
4462 can thread the branch. */
4463 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
4464 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
4465 && (comparison_dominates_p (code1
, code2
)
4466 || comparison_dominates_p (code1
, reverse_condition (code2
))))
4468 t1
= prev_nonnote_insn (b1
);
4469 t2
= prev_nonnote_insn (b2
);
4471 while (t1
!= 0 && t2
!= 0)
4475 /* We have reached the target of the first branch.
4476 If there are no pending register equivalents,
4477 we know that this branch will either always
4478 succeed (if the senses of the two branches are
4479 the same) or always fail (if not). */
4482 if (num_same_regs
!= 0)
4485 if (comparison_dominates_p (code1
, code2
))
4486 new_label
= JUMP_LABEL (b2
);
4488 new_label
= get_label_after (b2
);
4490 if (JUMP_LABEL (b1
) != new_label
)
4492 rtx prev
= PREV_INSN (new_label
);
4494 if (flag_before_loop
4495 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
4497 /* Don't thread to the loop label. If a loop
4498 label is reused, loop optimization will
4499 be disabled for that loop. */
4500 new_label
= gen_label_rtx ();
4501 emit_label_after (new_label
, PREV_INSN (prev
));
4503 changed
|= redirect_jump (b1
, new_label
);
4508 /* If either of these is not a normal insn (it might be
4509 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
4510 have already been skipped above.) Similarly, fail
4511 if the insns are different. */
4512 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
4513 || recog_memoized (t1
) != recog_memoized (t2
)
4514 || ! rtx_equal_for_thread_p (PATTERN (t1
),
4518 t1
= prev_nonnote_insn (t1
);
4519 t2
= prev_nonnote_insn (t2
);
4526 /* This is like RTX_EQUAL_P except that it knows about our handling of
4527 possibly equivalent registers and knows to consider volatile and
4528 modified objects as not equal.
4530 YINSN is the insn containing Y. */
4533 rtx_equal_for_thread_p (x
, y
, yinsn
)
4539 register enum rtx_code code
;
4542 code
= GET_CODE (x
);
4543 /* Rtx's of different codes cannot be equal. */
4544 if (code
!= GET_CODE (y
))
4547 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4548 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4550 if (GET_MODE (x
) != GET_MODE (y
))
4553 /* For floating-point, consider everything unequal. This is a bit
4554 pessimistic, but this pass would only rarely do anything for FP
4556 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
4557 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
4560 /* For commutative operations, the RTX match if the operand match in any
4561 order. Also handle the simple binary and unary cases without a loop. */
4562 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
4563 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4564 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
4565 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
4566 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
4567 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
4568 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4569 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
4570 else if (GET_RTX_CLASS (code
) == '1')
4571 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4573 /* Handle special-cases first. */
4577 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
4580 /* If neither is user variable or hard register, check for possible
4582 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
4583 || REGNO (x
) < FIRST_PSEUDO_REGISTER
4584 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
4587 if (same_regs
[REGNO (x
)] == -1)
4589 same_regs
[REGNO (x
)] = REGNO (y
);
4592 /* If this is the first time we are seeing a register on the `Y'
4593 side, see if it is the last use. If not, we can't thread the
4594 jump, so mark it as not equivalent. */
4595 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
4601 return (same_regs
[REGNO (x
)] == REGNO (y
));
4606 /* If memory modified or either volatile, not equivalent.
4607 Else, check address. */
4608 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4611 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4614 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4620 /* Cancel a pending `same_regs' if setting equivalenced registers.
4621 Then process source. */
4622 if (GET_CODE (SET_DEST (x
)) == REG
4623 && GET_CODE (SET_DEST (y
)) == REG
)
4625 if (same_regs
[REGNO (SET_DEST (x
))] == REGNO (SET_DEST (y
)))
4627 same_regs
[REGNO (SET_DEST (x
))] = -1;
4630 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
4634 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
4637 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
4640 return XEXP (x
, 0) == XEXP (y
, 0);
4643 return XSTR (x
, 0) == XSTR (y
, 0);
4649 fmt
= GET_RTX_FORMAT (code
);
4650 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4655 if (XWINT (x
, i
) != XWINT (y
, i
))
4661 if (XINT (x
, i
) != XINT (y
, i
))
4667 /* Two vectors must have the same length. */
4668 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
4671 /* And the corresponding elements must match. */
4672 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4673 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
4674 XVECEXP (y
, i
, j
), yinsn
) == 0)
4679 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
4685 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4690 /* These are just backpointers, so they don't matter. */
4696 /* It is believed that rtx's at this level will never
4697 contain anything but integers and other rtx's,
4698 except for within LABEL_REFs and SYMBOL_REFs. */