1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
34 Functions not supposed for generic use:
35 - Infrastructure to determine quickly basic block for insn
36 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
37 - Edge redirection with updating and optimizing of insn chain
38 block_label, tidy_fallthru_edge, force_nonfallthru */
42 #include "coretypes.h"
46 #include "hard-reg-set.h"
47 #include "basic-block.h"
56 #include "insn-config.h"
57 #include "cfglayout.h"
60 /* Stubs in case we don't have a return insn. */
63 #define gen_return() NULL_RTX
66 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
67 /* ??? Should probably be using LABEL_NUSES instead. It would take a
68 bit of surgery to be able to use or co-opt the routines in jump. */
70 rtx tail_recursion_label_list
;
72 static int can_delete_note_p (rtx
);
73 static int can_delete_label_p (rtx
);
74 static void commit_one_edge_insertion (edge
, int);
75 static rtx
last_loop_beg_note (rtx
);
76 static bool back_edge_of_syntactic_loop_p (basic_block
, basic_block
);
77 basic_block
force_nonfallthru_and_redirect (edge
, basic_block
);
78 static basic_block
rtl_split_edge (edge
);
79 static int rtl_verify_flow_info (void);
80 static edge
cfg_layout_split_block (basic_block
, void *);
81 static bool cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
82 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
83 static void cfg_layout_delete_block (basic_block
);
84 static void rtl_delete_block (basic_block
);
85 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
86 static bool rtl_redirect_edge_and_branch (edge
, basic_block
);
87 static edge
rtl_split_block (basic_block
, void *);
88 static void rtl_dump_bb (basic_block
, FILE *);
89 static int rtl_verify_flow_info_1 (void);
90 static void mark_killed_regs (rtx
, rtx
, void *);
92 /* Return true if NOTE is not one of the ones that must be kept paired,
93 so that we may simply delete it. */
96 can_delete_note_p (rtx note
)
98 return (NOTE_LINE_NUMBER (note
) == NOTE_INSN_DELETED
99 || NOTE_LINE_NUMBER (note
) == NOTE_INSN_BASIC_BLOCK
100 || NOTE_LINE_NUMBER (note
) == NOTE_INSN_PREDICTION
);
103 /* True if a given label can be deleted. */
106 can_delete_label_p (rtx label
)
108 return (!LABEL_PRESERVE_P (label
)
109 /* User declared labels must be preserved. */
110 && LABEL_NAME (label
) == 0
111 && !in_expr_list_p (forced_labels
, label
)
112 && !in_expr_list_p (label_value_list
, label
));
115 /* Delete INSN by patching it out. Return the next insn. */
118 delete_insn (rtx insn
)
120 rtx next
= NEXT_INSN (insn
);
122 bool really_delete
= true;
124 if (GET_CODE (insn
) == CODE_LABEL
)
126 /* Some labels can't be directly removed from the INSN chain, as they
127 might be references via variables, constant pool etc.
128 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
129 if (! can_delete_label_p (insn
))
131 const char *name
= LABEL_NAME (insn
);
133 really_delete
= false;
134 PUT_CODE (insn
, NOTE
);
135 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
136 NOTE_SOURCE_FILE (insn
) = name
;
139 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
144 /* If this insn has already been deleted, something is very wrong. */
145 if (INSN_DELETED_P (insn
))
148 INSN_DELETED_P (insn
) = 1;
151 /* If deleting a jump, decrement the use count of the label. Deleting
152 the label itself should happen in the normal course of block merging. */
153 if (GET_CODE (insn
) == JUMP_INSN
155 && GET_CODE (JUMP_LABEL (insn
)) == CODE_LABEL
)
156 LABEL_NUSES (JUMP_LABEL (insn
))--;
158 /* Also if deleting an insn that references a label. */
159 else if ((note
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
)) != NULL_RTX
160 && GET_CODE (XEXP (note
, 0)) == CODE_LABEL
)
161 LABEL_NUSES (XEXP (note
, 0))--;
163 if (GET_CODE (insn
) == JUMP_INSN
164 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
165 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
167 rtx pat
= PATTERN (insn
);
168 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
169 int len
= XVECLEN (pat
, diff_vec_p
);
172 for (i
= 0; i
< len
; i
++)
174 rtx label
= XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0);
176 /* When deleting code in bulk (e.g. removing many unreachable
177 blocks) we can delete a label that's a target of the vector
178 before deleting the vector itself. */
179 if (GET_CODE (label
) != NOTE
)
180 LABEL_NUSES (label
)--;
187 /* Like delete_insn but also purge dead edges from BB. */
189 delete_insn_and_edges (rtx insn
)
195 && BLOCK_FOR_INSN (insn
)
196 && BLOCK_FOR_INSN (insn
)->end
== insn
)
198 x
= delete_insn (insn
);
200 purge_dead_edges (BLOCK_FOR_INSN (insn
));
204 /* Unlink a chain of insns between START and FINISH, leaving notes
205 that must be paired. */
208 delete_insn_chain (rtx start
, rtx finish
)
212 /* Unchain the insns one by one. It would be quicker to delete all of these
213 with a single unchaining, rather than one at a time, but we need to keep
217 next
= NEXT_INSN (start
);
218 if (GET_CODE (start
) == NOTE
&& !can_delete_note_p (start
))
221 next
= delete_insn (start
);
229 /* Like delete_insn but also purge dead edges from BB. */
231 delete_insn_chain_and_edges (rtx first
, rtx last
)
236 && BLOCK_FOR_INSN (last
)
237 && BLOCK_FOR_INSN (last
)->end
== last
)
239 delete_insn_chain (first
, last
);
241 purge_dead_edges (BLOCK_FOR_INSN (last
));
244 /* Create a new basic block consisting of the instructions between HEAD and END
245 inclusive. This function is designed to allow fast BB construction - reuses
246 the note and basic block struct in BB_NOTE, if any and do not grow
247 BASIC_BLOCK chain and should be used directly only by CFG construction code.
248 END can be NULL in to create new empty basic block before HEAD. Both END
249 and HEAD can be NULL to create basic block at the end of INSN chain.
250 AFTER is the basic block we should be put after. */
253 create_basic_block_structure (rtx head
, rtx end
, rtx bb_note
, basic_block after
)
258 && ! RTX_INTEGRATED_P (bb_note
)
259 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
262 /* If we found an existing note, thread it back onto the chain. */
266 if (GET_CODE (head
) == CODE_LABEL
)
270 after
= PREV_INSN (head
);
274 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
275 reorder_insns_nobb (bb_note
, bb_note
, after
);
279 /* Otherwise we must create a note and a basic block structure. */
285 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
286 else if (GET_CODE (head
) == CODE_LABEL
&& end
)
288 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
294 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
300 NOTE_BASIC_BLOCK (bb_note
) = bb
;
303 /* Always include the bb note in the block. */
304 if (NEXT_INSN (end
) == bb_note
)
309 bb
->index
= last_basic_block
++;
311 link_block (bb
, after
);
312 BASIC_BLOCK (bb
->index
) = bb
;
313 update_bb_for_insn (bb
);
315 /* Tag the block so that we know it has been used when considering
316 other basic block notes. */
322 /* Create new basic block consisting of instructions in between HEAD and END
323 and place it to the BB chain after block AFTER. END can be NULL in to
324 create new empty basic block before HEAD. Both END and HEAD can be NULL to
325 create basic block at the end of INSN chain. */
328 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
330 rtx head
= headp
, end
= endp
;
333 /* Place the new block just after the end. */
334 VARRAY_GROW (basic_block_info
, last_basic_block
+1);
338 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
344 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
346 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
348 cfg_layout_initialize_rbi (newbb
);
352 /* Delete the insns in a (non-live) block. We physically delete every
353 non-deleted-note insn, and update the flow graph appropriately.
355 Return nonzero if we deleted an exception handler. */
357 /* ??? Preserving all such notes strikes me as wrong. It would be nice
358 to post-process the stream to remove empty blocks, loops, ranges, etc. */
361 rtl_delete_block (basic_block b
)
365 /* If the head of this block is a CODE_LABEL, then it might be the
366 label for an exception handler which can't be reached.
368 We need to remove the label from the exception_handler_label list
369 and remove the associated NOTE_INSN_EH_REGION_BEG and
370 NOTE_INSN_EH_REGION_END notes. */
372 /* Get rid of all NOTE_INSN_PREDICTIONs and NOTE_INSN_LOOP_CONTs
373 hanging before the block. */
375 for (insn
= PREV_INSN (b
->head
); insn
; insn
= PREV_INSN (insn
))
377 if (GET_CODE (insn
) != NOTE
)
379 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_PREDICTION
380 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
381 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
386 never_reached_warning (insn
, b
->end
);
388 if (GET_CODE (insn
) == CODE_LABEL
)
389 maybe_remove_eh_handler (insn
);
391 /* Include any jump table following the basic block. */
393 if (tablejump_p (end
, NULL
, &tmp
))
396 /* Include any barrier that may follow the basic block. */
397 tmp
= next_nonnote_insn (end
);
398 if (tmp
&& GET_CODE (tmp
) == BARRIER
)
401 /* Selectively delete the entire chain. */
403 delete_insn_chain (insn
, end
);
405 /* Remove the edges into and out of this block. Note that there may
406 indeed be edges in, if we are removing an unreachable loop. */
407 while (b
->pred
!= NULL
)
408 remove_edge (b
->pred
);
409 while (b
->succ
!= NULL
)
410 remove_edge (b
->succ
);
415 /* Remove the basic block from the array. */
419 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
422 compute_bb_for_insn (void)
431 for (insn
= bb
->head
; ; insn
= NEXT_INSN (insn
))
433 BLOCK_FOR_INSN (insn
) = bb
;
440 /* Release the basic_block_for_insn array. */
443 free_bb_for_insn (void)
446 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
447 if (GET_CODE (insn
) != BARRIER
)
448 BLOCK_FOR_INSN (insn
) = NULL
;
451 /* Update insns block within BB. */
454 update_bb_for_insn (basic_block bb
)
458 for (insn
= bb
->head
; ; insn
= NEXT_INSN (insn
))
460 if (GET_CODE (insn
) != BARRIER
)
461 set_block_for_insn (insn
, bb
);
467 /* Split a block BB after insn INSN creating a new fallthru edge.
468 Return the new edge. Note that to keep other parts of the compiler happy,
469 this function renumbers all the basic blocks so that the new
470 one has a number one greater than the block split. */
473 rtl_split_block (basic_block bb
, void *insnp
)
480 /* There is no point splitting the block after its end. */
484 /* Create the new basic block. */
485 new_bb
= create_basic_block (NEXT_INSN (insn
), bb
->end
, bb
);
486 new_bb
->count
= bb
->count
;
487 new_bb
->frequency
= bb
->frequency
;
488 new_bb
->loop_depth
= bb
->loop_depth
;
491 /* Redirect the outgoing edges. */
492 new_bb
->succ
= bb
->succ
;
494 for (e
= new_bb
->succ
; e
; e
= e
->succ_next
)
497 new_edge
= make_single_succ_edge (bb
, new_bb
, EDGE_FALLTHRU
);
499 if (bb
->global_live_at_start
)
501 new_bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
502 new_bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
503 COPY_REG_SET (new_bb
->global_live_at_end
, bb
->global_live_at_end
);
505 /* We now have to calculate which registers are live at the end
506 of the split basic block and at the start of the new basic
507 block. Start with those registers that are known to be live
508 at the end of the original basic block and get
509 propagate_block to determine which registers are live. */
510 COPY_REG_SET (new_bb
->global_live_at_start
, bb
->global_live_at_end
);
511 propagate_block (new_bb
, new_bb
->global_live_at_start
, NULL
, NULL
, 0);
512 COPY_REG_SET (bb
->global_live_at_end
,
513 new_bb
->global_live_at_start
);
514 #ifdef HAVE_conditional_execution
515 /* In the presence of conditional execution we are not able to update
516 liveness precisely. */
517 if (reload_completed
)
519 bb
->flags
|= BB_DIRTY
;
520 new_bb
->flags
|= BB_DIRTY
;
528 /* Assume that the code of basic block B has been merged into A.
529 Do corresponding CFG updates: redirect edges accordingly etc. */
531 update_cfg_after_block_merging (basic_block a
, basic_block b
)
535 /* Normally there should only be one successor of A and that is B, but
536 partway though the merge of blocks for conditional_execution we'll
537 be merging a TEST block with THEN and ELSE successors. Free the
538 whole lot of them and hope the caller knows what they're doing. */
540 remove_edge (a
->succ
);
542 /* Adjust the edges out of B for the new owner. */
543 for (e
= b
->succ
; e
; e
= e
->succ_next
)
546 a
->flags
|= b
->flags
;
548 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
549 b
->pred
= b
->succ
= NULL
;
550 a
->global_live_at_end
= b
->global_live_at_end
;
555 /* Blocks A and B are to be merged into a single block A. The insns
556 are already contiguous. */
559 rtl_merge_blocks (basic_block a
, basic_block b
)
561 rtx b_head
= b
->head
, b_end
= b
->end
, a_end
= a
->end
;
562 rtx del_first
= NULL_RTX
, del_last
= NULL_RTX
;
565 /* If there was a CODE_LABEL beginning B, delete it. */
566 if (GET_CODE (b_head
) == CODE_LABEL
)
568 /* Detect basic blocks with nothing but a label. This can happen
569 in particular at the end of a function. */
573 del_first
= del_last
= b_head
;
574 b_head
= NEXT_INSN (b_head
);
577 /* Delete the basic block note and handle blocks containing just that
579 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
587 b_head
= NEXT_INSN (b_head
);
590 /* If there was a jump out of A, delete it. */
591 if (GET_CODE (a_end
) == JUMP_INSN
)
595 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
596 if (GET_CODE (prev
) != NOTE
597 || NOTE_LINE_NUMBER (prev
) == NOTE_INSN_BASIC_BLOCK
604 /* If this was a conditional jump, we need to also delete
605 the insn that set cc0. */
606 if (only_sets_cc0_p (prev
))
610 prev
= prev_nonnote_insn (prev
);
617 a_end
= PREV_INSN (del_first
);
619 else if (GET_CODE (NEXT_INSN (a_end
)) == BARRIER
)
620 del_first
= NEXT_INSN (a_end
);
622 update_cfg_after_block_merging (a
, b
);
624 /* Delete everything marked above as well as crap that might be
625 hanging out between the two blocks. */
626 delete_insn_chain (del_first
, del_last
);
628 /* Reassociate the insns of B with A. */
633 for (x
= a_end
; x
!= b_end
; x
= NEXT_INSN (x
))
634 set_block_for_insn (x
, a
);
636 set_block_for_insn (b_end
, a
);
644 /* Return true when block A and B can be merged. */
646 rtl_can_merge_blocks (basic_block a
,basic_block b
)
648 /* There must be exactly one edge in between the blocks. */
649 return (a
->succ
&& !a
->succ
->succ_next
&& a
->succ
->dest
== b
650 && !b
->pred
->pred_next
&& a
!= b
651 /* Must be simple edge. */
652 && !(a
->succ
->flags
& EDGE_COMPLEX
)
654 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
655 /* If the jump insn has side effects,
656 we can't kill the edge. */
657 && (GET_CODE (a
->end
) != JUMP_INSN
659 ? simplejump_p (a
->end
) : onlyjump_p (a
->end
))));
662 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
666 block_label (basic_block block
)
668 if (block
== EXIT_BLOCK_PTR
)
671 if (GET_CODE (block
->head
) != CODE_LABEL
)
673 block
->head
= emit_label_before (gen_label_rtx (), block
->head
);
679 /* Attempt to perform edge redirection by replacing possibly complex jump
680 instruction by unconditional jump or removing jump completely. This can
681 apply only if all edges now point to the same block. The parameters and
682 return values are equivalent to redirect_edge_and_branch. */
685 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
687 basic_block src
= e
->src
;
688 rtx insn
= src
->end
, kill_from
;
693 /* Verify that all targets will be TARGET. */
694 for (tmp
= src
->succ
; tmp
; tmp
= tmp
->succ_next
)
695 if (tmp
->dest
!= target
&& tmp
!= e
)
698 if (tmp
|| !onlyjump_p (insn
))
700 if ((!optimize
|| flow2_completed
) && tablejump_p (insn
, NULL
, NULL
))
703 /* Avoid removing branch with side effects. */
704 set
= single_set (insn
);
705 if (!set
|| side_effects_p (set
))
708 /* In case we zap a conditional jump, we'll need to kill
709 the cc0 setter too. */
712 if (reg_mentioned_p (cc0_rtx
, PATTERN (insn
)))
713 kill_from
= PREV_INSN (insn
);
716 /* See if we can create the fallthru edge. */
717 if (in_cfglayout
|| can_fallthru (src
, target
))
720 fprintf (rtl_dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
723 /* Selectively unlink whole insn chain. */
726 rtx insn
= src
->rbi
->footer
;
728 delete_insn_chain (kill_from
, src
->end
);
730 /* Remove barriers but keep jumptables. */
733 if (GET_CODE (insn
) == BARRIER
)
735 if (PREV_INSN (insn
))
736 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
738 src
->rbi
->footer
= NEXT_INSN (insn
);
739 if (NEXT_INSN (insn
))
740 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
742 if (GET_CODE (insn
) == CODE_LABEL
)
744 insn
= NEXT_INSN (insn
);
748 delete_insn_chain (kill_from
, PREV_INSN (target
->head
));
751 /* If this already is simplejump, redirect it. */
752 else if (simplejump_p (insn
))
754 if (e
->dest
== target
)
757 fprintf (rtl_dump_file
, "Redirecting jump %i from %i to %i.\n",
758 INSN_UID (insn
), e
->dest
->index
, target
->index
);
759 if (!redirect_jump (insn
, block_label (target
), 0))
761 if (target
== EXIT_BLOCK_PTR
)
767 /* Cannot do anything for target exit block. */
768 else if (target
== EXIT_BLOCK_PTR
)
771 /* Or replace possibly complicated jump insn by simple jump insn. */
774 rtx target_label
= block_label (target
);
775 rtx barrier
, label
, table
;
777 emit_jump_insn_after (gen_jump (target_label
), insn
);
778 JUMP_LABEL (src
->end
) = target_label
;
779 LABEL_NUSES (target_label
)++;
781 fprintf (rtl_dump_file
, "Replacing insn %i by jump %i\n",
782 INSN_UID (insn
), INSN_UID (src
->end
));
785 delete_insn_chain (kill_from
, insn
);
787 /* Recognize a tablejump that we are converting to a
788 simple jump and remove its associated CODE_LABEL
789 and ADDR_VEC or ADDR_DIFF_VEC. */
790 if (tablejump_p (insn
, &label
, &table
))
791 delete_insn_chain (label
, table
);
793 barrier
= next_nonnote_insn (src
->end
);
794 if (!barrier
|| GET_CODE (barrier
) != BARRIER
)
795 emit_barrier_after (src
->end
);
798 /* Keep only one edge out and set proper flags. */
799 while (src
->succ
->succ_next
)
800 remove_edge (src
->succ
);
803 e
->flags
= EDGE_FALLTHRU
;
807 e
->probability
= REG_BR_PROB_BASE
;
808 e
->count
= src
->count
;
810 /* We don't want a block to end on a line-number note since that has
811 the potential of changing the code between -g and not -g. */
812 while (GET_CODE (e
->src
->end
) == NOTE
813 && NOTE_LINE_NUMBER (e
->src
->end
) >= 0)
814 delete_insn (e
->src
->end
);
816 if (e
->dest
!= target
)
817 redirect_edge_succ (e
, target
);
822 /* Return last loop_beg note appearing after INSN, before start of next
823 basic block. Return INSN if there are no such notes.
825 When emitting jump to redirect a fallthru edge, it should always appear
826 after the LOOP_BEG notes, as loop optimizer expect loop to either start by
827 fallthru edge or jump following the LOOP_BEG note jumping to the loop exit
831 last_loop_beg_note (rtx insn
)
835 for (insn
= NEXT_INSN (insn
); insn
&& GET_CODE (insn
) == NOTE
836 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_BASIC_BLOCK
;
837 insn
= NEXT_INSN (insn
))
838 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
844 /* Redirect edge representing branch of (un)conditional jump or tablejump. */
846 redirect_branch_edge (edge e
, basic_block target
)
849 rtx old_label
= e
->dest
->head
;
850 basic_block src
= e
->src
;
853 /* We can only redirect non-fallthru edges of jump insn. */
854 if (e
->flags
& EDGE_FALLTHRU
)
856 else if (GET_CODE (insn
) != JUMP_INSN
)
859 /* Recognize a tablejump and adjust all matching cases. */
860 if (tablejump_p (insn
, NULL
, &tmp
))
864 rtx new_label
= block_label (target
);
866 if (target
== EXIT_BLOCK_PTR
)
868 if (GET_CODE (PATTERN (tmp
)) == ADDR_VEC
)
869 vec
= XVEC (PATTERN (tmp
), 0);
871 vec
= XVEC (PATTERN (tmp
), 1);
873 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
874 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
876 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
877 --LABEL_NUSES (old_label
);
878 ++LABEL_NUSES (new_label
);
881 /* Handle casesi dispatch insns. */
882 if ((tmp
= single_set (insn
)) != NULL
883 && SET_DEST (tmp
) == pc_rtx
884 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
885 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
886 && XEXP (XEXP (SET_SRC (tmp
), 2), 0) == old_label
)
888 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (VOIDmode
,
890 --LABEL_NUSES (old_label
);
891 ++LABEL_NUSES (new_label
);
896 /* ?? We may play the games with moving the named labels from
897 one basic block to the other in case only one computed_jump is
899 if (computed_jump_p (insn
)
900 /* A return instruction can't be redirected. */
901 || returnjump_p (insn
))
904 /* If the insn doesn't go where we think, we're confused. */
905 if (JUMP_LABEL (insn
) != old_label
)
908 /* If the substitution doesn't succeed, die. This can happen
909 if the back end emitted unrecognizable instructions or if
910 target is exit block on some arches. */
911 if (!redirect_jump (insn
, block_label (target
), 0))
913 if (target
== EXIT_BLOCK_PTR
)
920 fprintf (rtl_dump_file
, "Edge %i->%i redirected to %i\n",
921 e
->src
->index
, e
->dest
->index
, target
->index
);
923 if (e
->dest
!= target
)
924 redirect_edge_succ_nodup (e
, target
);
928 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
929 expense of adding new instructions or reordering basic blocks.
931 Function can be also called with edge destination equivalent to the TARGET.
932 Then it should try the simplifications and do nothing if none is possible.
934 Return true if transformation succeeded. We still return false in case E
935 already destinated TARGET and we didn't managed to simplify instruction
939 rtl_redirect_edge_and_branch (e
, target
)
943 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
946 if (try_redirect_by_replacing_jump (e
, target
, false))
949 /* Do this fast path late, as we want above code to simplify for cases
950 where called on single edge leaving basic block containing nontrivial
952 else if (e
->dest
== target
)
954 else if (!redirect_branch_edge (e
, target
))
960 /* Like force_nonfallthru below, but additionally performs redirection
961 Used by redirect_edge_and_branch_force. */
964 force_nonfallthru_and_redirect (edge e
, basic_block target
)
966 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
969 int abnormal_edge_flags
= 0;
971 /* In the case the last instruction is conditional jump to the next
972 instruction, first redirect the jump itself and then continue
973 by creating a basic block afterwards to redirect fallthru edge. */
974 if (e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
975 && any_condjump_p (e
->src
->end
)
976 /* When called from cfglayout, fallthru edges do not
977 necessarily go to the next block. */
978 && e
->src
->next_bb
== e
->dest
979 && JUMP_LABEL (e
->src
->end
) == e
->dest
->head
)
982 edge b
= unchecked_make_edge (e
->src
, target
, 0);
984 if (!redirect_jump (e
->src
->end
, block_label (target
), 0))
986 note
= find_reg_note (e
->src
->end
, REG_BR_PROB
, NULL_RTX
);
989 int prob
= INTVAL (XEXP (note
, 0));
991 b
->probability
= prob
;
992 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
993 e
->probability
-= e
->probability
;
994 e
->count
-= b
->count
;
995 if (e
->probability
< 0)
1002 if (e
->flags
& EDGE_ABNORMAL
)
1004 /* Irritating special case - fallthru edge to the same block as abnormal
1006 We can't redirect abnormal edge, but we still can split the fallthru
1007 one and create separate abnormal edge to original destination.
1008 This allows bb-reorder to make such edge non-fallthru. */
1009 if (e
->dest
!= target
)
1011 abnormal_edge_flags
= e
->flags
& ~(EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
);
1012 e
->flags
&= EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
;
1014 else if (!(e
->flags
& EDGE_FALLTHRU
))
1016 else if (e
->src
== ENTRY_BLOCK_PTR
)
1018 /* We can't redirect the entry block. Create an empty block at the
1019 start of the function which we use to add the new jump. */
1021 basic_block bb
= create_basic_block (e
->dest
->head
, NULL
, ENTRY_BLOCK_PTR
);
1023 /* Change the existing edge's source to be the new block, and add
1024 a new edge from the entry block to the new block. */
1026 for (pe1
= &ENTRY_BLOCK_PTR
->succ
; *pe1
; pe1
= &(*pe1
)->succ_next
)
1029 *pe1
= e
->succ_next
;
1034 make_single_succ_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FALLTHRU
);
1037 if (e
->src
->succ
->succ_next
|| abnormal_edge_flags
)
1039 /* Create the new structures. */
1041 /* Position the new block correctly relative to loop notes. */
1042 note
= last_loop_beg_note (e
->src
->end
);
1043 note
= NEXT_INSN (note
);
1045 /* ... and ADDR_VECs. */
1047 && GET_CODE (note
) == CODE_LABEL
1049 && GET_CODE (NEXT_INSN (note
)) == JUMP_INSN
1050 && (GET_CODE (PATTERN (NEXT_INSN (note
))) == ADDR_DIFF_VEC
1051 || GET_CODE (PATTERN (NEXT_INSN (note
))) == ADDR_VEC
))
1052 note
= NEXT_INSN (NEXT_INSN (note
));
1054 jump_block
= create_basic_block (note
, NULL
, e
->src
);
1055 jump_block
->count
= e
->count
;
1056 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1057 jump_block
->loop_depth
= target
->loop_depth
;
1059 if (target
->global_live_at_start
)
1061 jump_block
->global_live_at_start
1062 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1063 jump_block
->global_live_at_end
1064 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1065 COPY_REG_SET (jump_block
->global_live_at_start
,
1066 target
->global_live_at_start
);
1067 COPY_REG_SET (jump_block
->global_live_at_end
,
1068 target
->global_live_at_start
);
1072 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1073 new_edge
->probability
= e
->probability
;
1074 new_edge
->count
= e
->count
;
1076 /* Redirect old edge. */
1077 redirect_edge_pred (e
, jump_block
);
1078 e
->probability
= REG_BR_PROB_BASE
;
1080 new_bb
= jump_block
;
1083 jump_block
= e
->src
;
1085 e
->flags
&= ~EDGE_FALLTHRU
;
1086 if (target
== EXIT_BLOCK_PTR
)
1089 emit_jump_insn_after (gen_return (), jump_block
->end
);
1095 rtx label
= block_label (target
);
1096 emit_jump_insn_after (gen_jump (label
), jump_block
->end
);
1097 JUMP_LABEL (jump_block
->end
) = label
;
1098 LABEL_NUSES (label
)++;
1101 emit_barrier_after (jump_block
->end
);
1102 redirect_edge_succ_nodup (e
, target
);
1104 if (abnormal_edge_flags
)
1105 make_edge (src
, target
, abnormal_edge_flags
);
1110 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1111 (and possibly create new basic block) to make edge non-fallthru.
1112 Return newly created BB or NULL if none. */
1115 force_nonfallthru (edge e
)
1117 return force_nonfallthru_and_redirect (e
, e
->dest
);
1120 /* Redirect edge even at the expense of creating new jump insn or
1121 basic block. Return new basic block if created, NULL otherwise.
1122 Abort if conversion is impossible. */
1125 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1127 if (redirect_edge_and_branch (e
, target
)
1128 || e
->dest
== target
)
1131 /* In case the edge redirection failed, try to force it to be non-fallthru
1132 and redirect newly created simplejump. */
1133 return force_nonfallthru_and_redirect (e
, target
);
1136 /* The given edge should potentially be a fallthru edge. If that is in
1137 fact true, delete the jump and barriers that are in the way. */
1140 tidy_fallthru_edge (edge e
, basic_block b
, basic_block c
)
1144 /* ??? In a late-running flow pass, other folks may have deleted basic
1145 blocks by nopping out blocks, leaving multiple BARRIERs between here
1146 and the target label. They ought to be chastized and fixed.
1148 We can also wind up with a sequence of undeletable labels between
1149 one block and the next.
1151 So search through a sequence of barriers, labels, and notes for
1152 the head of block C and assert that we really do fall through. */
1154 for (q
= NEXT_INSN (b
->end
); q
!= c
->head
; q
= NEXT_INSN (q
))
1158 /* Remove what will soon cease being the jump insn from the source block.
1159 If block B consisted only of this single jump, turn it into a deleted
1162 if (GET_CODE (q
) == JUMP_INSN
1164 && (any_uncondjump_p (q
)
1165 || (b
->succ
== e
&& e
->succ_next
== NULL
)))
1168 /* If this was a conditional jump, we need to also delete
1169 the insn that set cc0. */
1170 if (any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1176 /* We don't want a block to end on a line-number note since that has
1177 the potential of changing the code between -g and not -g. */
1178 while (GET_CODE (q
) == NOTE
&& NOTE_LINE_NUMBER (q
) >= 0)
1182 /* Selectively unlink the sequence. */
1183 if (q
!= PREV_INSN (c
->head
))
1184 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (c
->head
));
1186 e
->flags
|= EDGE_FALLTHRU
;
1189 /* Fix up edges that now fall through, or rather should now fall through
1190 but previously required a jump around now deleted blocks. Simplify
1191 the search by only examining blocks numerically adjacent, since this
1192 is how find_basic_blocks created them. */
1195 tidy_fallthru_edges (void)
1199 if (ENTRY_BLOCK_PTR
->next_bb
== EXIT_BLOCK_PTR
)
1202 FOR_BB_BETWEEN (b
, ENTRY_BLOCK_PTR
->next_bb
, EXIT_BLOCK_PTR
->prev_bb
, next_bb
)
1208 /* We care about simple conditional or unconditional jumps with
1211 If we had a conditional branch to the next instruction when
1212 find_basic_blocks was called, then there will only be one
1213 out edge for the block which ended with the conditional
1214 branch (since we do not create duplicate edges).
1216 Furthermore, the edge will be marked as a fallthru because we
1217 merge the flags for the duplicate edges. So we do not want to
1218 check that the edge is not a FALLTHRU edge. */
1220 if ((s
= b
->succ
) != NULL
1221 && ! (s
->flags
& EDGE_COMPLEX
)
1222 && s
->succ_next
== NULL
1224 /* If the jump insn has side effects, we can't tidy the edge. */
1225 && (GET_CODE (b
->end
) != JUMP_INSN
1226 || onlyjump_p (b
->end
)))
1227 tidy_fallthru_edge (s
, b
, c
);
1231 /* Helper function for split_edge. Return true in case edge BB2 to BB1
1232 is back edge of syntactic loop. */
1235 back_edge_of_syntactic_loop_p (basic_block bb1
, basic_block bb2
)
1244 /* ??? Could we guarantee that bb indices are monotone, so that we could
1245 just compare them? */
1246 for (bb
= bb1
; bb
&& bb
!= bb2
; bb
= bb
->next_bb
)
1252 for (insn
= bb1
->end
; insn
!= bb2
->head
&& count
>= 0;
1253 insn
= NEXT_INSN (insn
))
1254 if (GET_CODE (insn
) == NOTE
)
1256 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
1258 else if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
)
1265 /* Split a (typically critical) edge. Return the new block.
1266 Abort on abnormal edges.
1268 ??? The code generally expects to be called on critical edges.
1269 The case of a block ending in an unconditional jump to a
1270 block with multiple predecessors is not handled optimally. */
1273 rtl_split_edge (edge edge_in
)
1278 /* Abnormal edges cannot be split. */
1279 if ((edge_in
->flags
& EDGE_ABNORMAL
) != 0)
1282 /* We are going to place the new block in front of edge destination.
1283 Avoid existence of fallthru predecessors. */
1284 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1288 for (e
= edge_in
->dest
->pred
; e
; e
= e
->pred_next
)
1289 if (e
->flags
& EDGE_FALLTHRU
)
1293 force_nonfallthru (e
);
1296 /* Create the basic block note.
1298 Where we place the note can have a noticeable impact on the generated
1299 code. Consider this cfg:
1309 If we need to insert an insn on the edge from block 0 to block 1,
1310 we want to ensure the instructions we insert are outside of any
1311 loop notes that physically sit between block 0 and block 1. Otherwise
1312 we confuse the loop optimizer into thinking the loop is a phony. */
1314 if (edge_in
->dest
!= EXIT_BLOCK_PTR
1315 && PREV_INSN (edge_in
->dest
->head
)
1316 && GET_CODE (PREV_INSN (edge_in
->dest
->head
)) == NOTE
1317 && (NOTE_LINE_NUMBER (PREV_INSN (edge_in
->dest
->head
))
1318 == NOTE_INSN_LOOP_BEG
)
1319 && !back_edge_of_syntactic_loop_p (edge_in
->dest
, edge_in
->src
))
1320 before
= PREV_INSN (edge_in
->dest
->head
);
1321 else if (edge_in
->dest
!= EXIT_BLOCK_PTR
)
1322 before
= edge_in
->dest
->head
;
1326 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1327 bb
->count
= edge_in
->count
;
1328 bb
->frequency
= EDGE_FREQUENCY (edge_in
);
1330 /* ??? This info is likely going to be out of date very soon. */
1331 if (edge_in
->dest
->global_live_at_start
)
1333 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1334 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1335 COPY_REG_SET (bb
->global_live_at_start
,
1336 edge_in
->dest
->global_live_at_start
);
1337 COPY_REG_SET (bb
->global_live_at_end
,
1338 edge_in
->dest
->global_live_at_start
);
1341 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1343 /* For non-fallthry edges, we must adjust the predecessor's
1344 jump instruction to target our new block. */
1345 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1347 if (!redirect_edge_and_branch (edge_in
, bb
))
1351 redirect_edge_succ (edge_in
, bb
);
1356 /* Queue instructions for insertion on an edge between two basic blocks.
1357 The new instructions and basic blocks (if any) will not appear in the
1358 CFG until commit_edge_insertions is called. */
1361 insert_insn_on_edge (rtx pattern
, edge e
)
1363 /* We cannot insert instructions on an abnormal critical edge.
1364 It will be easier to find the culprit if we die now. */
1365 if ((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
))
1368 if (e
->insns
== NULL_RTX
)
1371 push_to_sequence (e
->insns
);
1373 emit_insn (pattern
);
1375 e
->insns
= get_insns ();
1379 /* Called from safe_insert_insn_on_edge through note_stores, marks live
1380 registers that are killed by the store. */
1382 mark_killed_regs (rtx reg
, rtx set ATTRIBUTE_UNUSED
, void *data
)
1384 regset killed
= data
;
1387 if (GET_CODE (reg
) == SUBREG
)
1388 reg
= SUBREG_REG (reg
);
1391 regno
= REGNO (reg
);
1392 if (regno
>= FIRST_PSEUDO_REGISTER
)
1393 SET_REGNO_REG_SET (killed
, regno
);
1396 for (i
= 0; i
< (int) HARD_REGNO_NREGS (regno
, GET_MODE (reg
)); i
++)
1397 SET_REGNO_REG_SET (killed
, regno
+ i
);
1401 /* Similar to insert_insn_on_edge, tries to put INSN to edge E. Additionally
1402 it checks whether this will not clobber the registers that are live on the
1403 edge (i.e. it requires liveness information to be up-to-date) and if there
1404 are some, then it tries to save and restore them. Returns true if
1407 safe_insert_insn_on_edge (rtx insn
, edge e
)
1410 regset_head killed_head
;
1411 regset killed
= INITIALIZE_REG_SET (killed_head
);
1412 rtx save_regs
= NULL_RTX
;
1413 int regno
, noccmode
;
1414 enum machine_mode mode
;
1416 #ifdef AVOID_CCMODE_COPIES
1422 for (x
= insn
; x
; x
= NEXT_INSN (x
))
1424 note_stores (PATTERN (x
), mark_killed_regs
, killed
);
1425 bitmap_operation (killed
, killed
, e
->dest
->global_live_at_start
,
1428 EXECUTE_IF_SET_IN_REG_SET (killed
, 0, regno
,
1430 mode
= regno
< FIRST_PSEUDO_REGISTER
1431 ? reg_raw_mode
[regno
]
1432 : GET_MODE (regno_reg_rtx
[regno
]);
1433 if (mode
== VOIDmode
)
1436 if (noccmode
&& mode
== CCmode
)
1439 save_regs
= alloc_EXPR_LIST (0,
1442 gen_raw_REG (mode
, regno
)),
1451 for (x
= save_regs
; x
; x
= XEXP (x
, 1))
1453 from
= XEXP (XEXP (x
, 0), 1);
1454 to
= XEXP (XEXP (x
, 0), 0);
1455 emit_move_insn (to
, from
);
1458 for (x
= save_regs
; x
; x
= XEXP (x
, 1))
1460 from
= XEXP (XEXP (x
, 0), 0);
1461 to
= XEXP (XEXP (x
, 0), 1);
1462 emit_move_insn (to
, from
);
1464 insn
= get_insns ();
1466 free_EXPR_LIST_list (&save_regs
);
1468 insert_insn_on_edge (insn
, e
);
1470 FREE_REG_SET (killed
);
1474 /* Update the CFG for the instructions queued on edge E. */
1477 commit_one_edge_insertion (edge e
, int watch_calls
)
1479 rtx before
= NULL_RTX
, after
= NULL_RTX
, insns
, tmp
, last
;
1480 basic_block bb
= NULL
;
1482 /* Pull the insns off the edge now since the edge might go away. */
1484 e
->insns
= NULL_RTX
;
1486 /* Special case -- avoid inserting code between call and storing
1487 its return value. */
1488 if (watch_calls
&& (e
->flags
& EDGE_FALLTHRU
) && !e
->dest
->pred
->pred_next
1489 && e
->src
!= ENTRY_BLOCK_PTR
1490 && GET_CODE (e
->src
->end
) == CALL_INSN
)
1492 rtx next
= next_nonnote_insn (e
->src
->end
);
1494 after
= e
->dest
->head
;
1495 /* The first insn after the call may be a stack pop, skip it. */
1497 && keep_with_call_p (next
))
1500 next
= next_nonnote_insn (next
);
1504 if (!before
&& !after
)
1506 /* Figure out where to put these things. If the destination has
1507 one predecessor, insert there. Except for the exit block. */
1508 if (e
->dest
->pred
->pred_next
== NULL
&& e
->dest
!= EXIT_BLOCK_PTR
)
1512 /* Get the location correct wrt a code label, and "nice" wrt
1513 a basic block note, and before everything else. */
1515 if (GET_CODE (tmp
) == CODE_LABEL
)
1516 tmp
= NEXT_INSN (tmp
);
1517 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1518 tmp
= NEXT_INSN (tmp
);
1519 if (tmp
== bb
->head
)
1522 after
= PREV_INSN (tmp
);
1524 after
= get_last_insn ();
1527 /* If the source has one successor and the edge is not abnormal,
1528 insert there. Except for the entry block. */
1529 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
1530 && e
->src
->succ
->succ_next
== NULL
1531 && e
->src
!= ENTRY_BLOCK_PTR
)
1535 /* It is possible to have a non-simple jump here. Consider a target
1536 where some forms of unconditional jumps clobber a register. This
1537 happens on the fr30 for example.
1539 We know this block has a single successor, so we can just emit
1540 the queued insns before the jump. */
1541 if (GET_CODE (bb
->end
) == JUMP_INSN
)
1542 for (before
= bb
->end
;
1543 GET_CODE (PREV_INSN (before
)) == NOTE
1544 && NOTE_LINE_NUMBER (PREV_INSN (before
)) ==
1545 NOTE_INSN_LOOP_BEG
; before
= PREV_INSN (before
))
1549 /* We'd better be fallthru, or we've lost track of what's what. */
1550 if ((e
->flags
& EDGE_FALLTHRU
) == 0)
1556 /* Otherwise we must split the edge. */
1559 bb
= split_edge (e
);
1564 /* Now that we've found the spot, do the insertion. */
1568 emit_insn_before (insns
, before
);
1569 last
= prev_nonnote_insn (before
);
1572 last
= emit_insn_after (insns
, after
);
1574 if (returnjump_p (last
))
1576 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1577 This is not currently a problem because this only happens
1578 for the (single) epilogue, which already has a fallthru edge
1582 if (e
->dest
!= EXIT_BLOCK_PTR
1583 || e
->succ_next
!= NULL
|| (e
->flags
& EDGE_FALLTHRU
) == 0)
1586 e
->flags
&= ~EDGE_FALLTHRU
;
1587 emit_barrier_after (last
);
1590 delete_insn (before
);
1592 else if (GET_CODE (last
) == JUMP_INSN
)
1595 /* Mark the basic block for find_sub_basic_blocks. */
1599 /* Update the CFG for all queued instructions. */
1602 commit_edge_insertions (void)
1606 bool changed
= false;
1608 #ifdef ENABLE_CHECKING
1609 verify_flow_info ();
1612 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1616 for (e
= bb
->succ
; e
; e
= next
)
1618 next
= e
->succ_next
;
1622 commit_one_edge_insertion (e
, false);
1630 blocks
= sbitmap_alloc (last_basic_block
);
1631 sbitmap_zero (blocks
);
1635 SET_BIT (blocks
, bb
->index
);
1636 /* Check for forgotten bb->aux values before commit_edge_insertions
1638 if (bb
->aux
!= &bb
->aux
)
1642 find_many_sub_basic_blocks (blocks
);
1643 sbitmap_free (blocks
);
1646 /* Update the CFG for all queued instructions, taking special care of inserting
1647 code on edges between call and storing its return value. */
1650 commit_edge_insertions_watch_calls (void)
1654 bool changed
= false;
1656 #ifdef ENABLE_CHECKING
1657 verify_flow_info ();
1660 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1664 for (e
= bb
->succ
; e
; e
= next
)
1666 next
= e
->succ_next
;
1670 commit_one_edge_insertion (e
, true);
1678 blocks
= sbitmap_alloc (last_basic_block
);
1679 sbitmap_zero (blocks
);
1683 SET_BIT (blocks
, bb
->index
);
1684 /* Check for forgotten bb->aux values before commit_edge_insertions
1686 if (bb
->aux
!= &bb
->aux
)
1690 find_many_sub_basic_blocks (blocks
);
1691 sbitmap_free (blocks
);
1694 /* Print out one basic block with live information at start and end. */
1697 rtl_dump_bb (basic_block bb
, FILE *outf
)
1702 fputs (";; Registers live at start:", outf
);
1703 dump_regset (bb
->global_live_at_start
, outf
);
1706 for (insn
= bb
->head
, last
= NEXT_INSN (bb
->end
); insn
!= last
;
1707 insn
= NEXT_INSN (insn
))
1708 print_rtl_single (outf
, insn
);
1710 fputs (";; Registers live at end:", outf
);
1711 dump_regset (bb
->global_live_at_end
, outf
);
1715 /* Like print_rtl, but also print out live information for the start of each
1719 print_rtl_with_bb (FILE *outf
, rtx rtx_first
)
1724 fprintf (outf
, "(nil)\n");
1727 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
1728 int max_uid
= get_max_uid ();
1730 = (basic_block
*) xcalloc (max_uid
, sizeof (basic_block
));
1732 = (basic_block
*) xcalloc (max_uid
, sizeof (basic_block
));
1733 enum bb_state
*in_bb_p
1734 = (enum bb_state
*) xcalloc (max_uid
, sizeof (enum bb_state
));
1738 FOR_EACH_BB_REVERSE (bb
)
1742 start
[INSN_UID (bb
->head
)] = bb
;
1743 end
[INSN_UID (bb
->end
)] = bb
;
1744 for (x
= bb
->head
; x
!= NULL_RTX
; x
= NEXT_INSN (x
))
1746 enum bb_state state
= IN_MULTIPLE_BB
;
1748 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
1750 in_bb_p
[INSN_UID (x
)] = state
;
1757 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
1761 if ((bb
= start
[INSN_UID (tmp_rtx
)]) != NULL
)
1763 fprintf (outf
, ";; Start of basic block %d, registers live:",
1765 dump_regset (bb
->global_live_at_start
, outf
);
1769 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
1770 && GET_CODE (tmp_rtx
) != NOTE
1771 && GET_CODE (tmp_rtx
) != BARRIER
)
1772 fprintf (outf
, ";; Insn is not within a basic block\n");
1773 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
1774 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
1776 did_output
= print_rtl_single (outf
, tmp_rtx
);
1778 if ((bb
= end
[INSN_UID (tmp_rtx
)]) != NULL
)
1780 fprintf (outf
, ";; End of basic block %d, registers live:\n",
1782 dump_regset (bb
->global_live_at_end
, outf
);
1795 if (current_function_epilogue_delay_list
!= 0)
1797 fprintf (outf
, "\n;; Insns in epilogue delay list:\n\n");
1798 for (tmp_rtx
= current_function_epilogue_delay_list
; tmp_rtx
!= 0;
1799 tmp_rtx
= XEXP (tmp_rtx
, 1))
1800 print_rtl_single (outf
, XEXP (tmp_rtx
, 0));
1805 update_br_prob_note (basic_block bb
)
1808 if (GET_CODE (bb
->end
) != JUMP_INSN
)
1810 note
= find_reg_note (bb
->end
, REG_BR_PROB
, NULL_RTX
);
1811 if (!note
|| INTVAL (XEXP (note
, 0)) == BRANCH_EDGE (bb
)->probability
)
1813 XEXP (note
, 0) = GEN_INT (BRANCH_EDGE (bb
)->probability
);
1816 /* Verify the CFG and RTL consistency common for both underlying RTL and
1819 Currently it does following checks:
1821 - test head/end pointers
1822 - overlapping of basic blocks
1823 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1824 - tails of basic blocks (ensure that boundary is necessary)
1825 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1826 and NOTE_INSN_BASIC_BLOCK
1828 In future it can be extended check a lot of other stuff as well
1829 (reachability of basic blocks, life information, etc. etc.). */
1831 rtl_verify_flow_info_1 (void)
1833 const int max_uid
= get_max_uid ();
1834 rtx last_head
= get_last_insn ();
1835 basic_block
*bb_info
;
1838 basic_block bb
, last_bb_seen
;
1840 bb_info
= (basic_block
*) xcalloc (max_uid
, sizeof (basic_block
));
1842 /* Check bb chain & numbers. */
1843 last_bb_seen
= ENTRY_BLOCK_PTR
;
1845 FOR_EACH_BB_REVERSE (bb
)
1847 rtx head
= bb
->head
;
1850 /* Verify the end of the basic block is in the INSN chain. */
1851 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
1857 error ("end insn %d for block %d not found in the insn stream",
1858 INSN_UID (end
), bb
->index
);
1862 /* Work backwards from the end to the head of the basic block
1863 to verify the head is in the RTL chain. */
1864 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
1866 /* While walking over the insn chain, verify insns appear
1867 in only one basic block and initialize the BB_INFO array
1868 used by other passes. */
1869 if (bb_info
[INSN_UID (x
)] != NULL
)
1871 error ("insn %d is in multiple basic blocks (%d and %d)",
1872 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
1876 bb_info
[INSN_UID (x
)] = bb
;
1883 error ("head insn %d for block %d not found in the insn stream",
1884 INSN_UID (head
), bb
->index
);
1891 /* Now check the basic blocks (boundaries etc.) */
1892 FOR_EACH_BB_REVERSE (bb
)
1894 int n_fallthru
= 0, n_eh
= 0, n_call
= 0, n_abnormal
= 0, n_branch
= 0;
1895 edge e
, fallthru
= NULL
;
1898 if (INSN_P (bb
->end
)
1899 && (note
= find_reg_note (bb
->end
, REG_BR_PROB
, NULL_RTX
))
1900 && bb
->succ
&& bb
->succ
->succ_next
1901 && any_condjump_p (bb
->end
))
1903 if (INTVAL (XEXP (note
, 0)) != BRANCH_EDGE (bb
)->probability
)
1905 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1906 INTVAL (XEXP (note
, 0)), BRANCH_EDGE (bb
)->probability
);
1910 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
1912 if (e
->flags
& EDGE_FALLTHRU
)
1913 n_fallthru
++, fallthru
= e
;
1915 if ((e
->flags
& ~(EDGE_DFS_BACK
| EDGE_CAN_FALLTHRU
| EDGE_IRREDUCIBLE_LOOP
)) == 0)
1918 if (e
->flags
& EDGE_ABNORMAL_CALL
)
1921 if (e
->flags
& EDGE_EH
)
1923 else if (e
->flags
& EDGE_ABNORMAL
)
1927 if (n_eh
&& GET_CODE (PATTERN (bb
->end
)) != RESX
1928 && !find_reg_note (bb
->end
, REG_EH_REGION
, NULL_RTX
))
1930 error ("Missing REG_EH_REGION note in the end of bb %i", bb
->index
);
1934 && (GET_CODE (bb
->end
) != JUMP_INSN
1935 || (n_branch
> 1 && (any_uncondjump_p (bb
->end
)
1936 || any_condjump_p (bb
->end
)))))
1938 error ("Too many outgoing branch edges from bb %i", bb
->index
);
1941 if (n_fallthru
&& any_uncondjump_p (bb
->end
))
1943 error ("Fallthru edge after unconditional jump %i", bb
->index
);
1946 if (n_branch
!= 1 && any_uncondjump_p (bb
->end
))
1948 error ("Wrong amount of branch edges after unconditional jump %i", bb
->index
);
1951 if (n_branch
!= 1 && any_condjump_p (bb
->end
)
1952 && JUMP_LABEL (bb
->end
) != fallthru
->dest
->head
)
1954 error ("Wrong amount of branch edges after conditional jump %i", bb
->index
);
1957 if (n_call
&& GET_CODE (bb
->end
) != CALL_INSN
)
1959 error ("Call edges for non-call insn in bb %i", bb
->index
);
1963 && (GET_CODE (bb
->end
) != CALL_INSN
&& n_call
!= n_abnormal
)
1964 && (GET_CODE (bb
->end
) != JUMP_INSN
1965 || any_condjump_p (bb
->end
)
1966 || any_uncondjump_p (bb
->end
)))
1968 error ("Abnormal edges for no purpose in bb %i", bb
->index
);
1972 for (x
= bb
->head
; x
!= NEXT_INSN (bb
->end
); x
= NEXT_INSN (x
))
1973 if (BLOCK_FOR_INSN (x
) != bb
)
1976 if (! BLOCK_FOR_INSN (x
))
1978 ("insn %d inside basic block %d but block_for_insn is NULL",
1979 INSN_UID (x
), bb
->index
);
1982 ("insn %d inside basic block %d but block_for_insn is %i",
1983 INSN_UID (x
), bb
->index
, BLOCK_FOR_INSN (x
)->index
);
1988 /* OK pointers are correct. Now check the header of basic
1989 block. It ought to contain optional CODE_LABEL followed
1990 by NOTE_BASIC_BLOCK. */
1992 if (GET_CODE (x
) == CODE_LABEL
)
1996 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2004 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2006 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2012 /* Do checks for empty blocks her. e */
2015 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2017 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2019 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2020 INSN_UID (x
), bb
->index
);
2027 if (control_flow_insn_p (x
))
2029 error ("in basic block %d:", bb
->index
);
2030 fatal_insn ("flow control insn inside a basic block", x
);
2040 /* Verify the CFG and RTL consistency common for both underlying RTL and
2043 Currently it does following checks:
2044 - all checks of rtl_verify_flow_info_1
2045 - check that all insns are in the basic blocks
2046 (except the switch handling code, barriers and notes)
2047 - check that all returns are followed by barriers
2048 - check that all fallthru edge points to the adjacent blocks. */
2050 rtl_verify_flow_info (void)
2053 int err
= rtl_verify_flow_info_1 ();
2056 const rtx rtx_first
= get_insns ();
2057 basic_block last_bb_seen
= ENTRY_BLOCK_PTR
, curr_bb
= NULL
;
2059 FOR_EACH_BB_REVERSE (bb
)
2062 for (e
= bb
->succ
; e
; e
= e
->succ_next
)
2063 if (e
->flags
& EDGE_FALLTHRU
)
2069 /* Ensure existence of barrier in BB with no fallthru edges. */
2070 for (insn
= bb
->end
; !insn
|| GET_CODE (insn
) != BARRIER
;
2071 insn
= NEXT_INSN (insn
))
2073 || (GET_CODE (insn
) == NOTE
2074 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BASIC_BLOCK
))
2076 error ("missing barrier after block %i", bb
->index
);
2081 else if (e
->src
!= ENTRY_BLOCK_PTR
2082 && e
->dest
!= EXIT_BLOCK_PTR
)
2086 if (e
->src
->next_bb
!= e
->dest
)
2089 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2090 e
->src
->index
, e
->dest
->index
);
2094 for (insn
= NEXT_INSN (e
->src
->end
); insn
!= e
->dest
->head
;
2095 insn
= NEXT_INSN (insn
))
2096 if (GET_CODE (insn
) == BARRIER
2097 #ifndef CASE_DROPS_THROUGH
2100 || (INSN_P (insn
) && ! JUMP_TABLE_DATA_P (insn
))
2104 error ("verify_flow_info: Incorrect fallthru %i->%i",
2105 e
->src
->index
, e
->dest
->index
);
2106 fatal_insn ("wrong insn in the fallthru edge", insn
);
2113 last_bb_seen
= ENTRY_BLOCK_PTR
;
2115 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2117 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2119 bb
= NOTE_BASIC_BLOCK (x
);
2122 if (bb
!= last_bb_seen
->next_bb
)
2123 internal_error ("basic blocks not laid down consecutively");
2125 curr_bb
= last_bb_seen
= bb
;
2130 switch (GET_CODE (x
))
2137 /* An addr_vec is placed outside any block block. */
2139 && GET_CODE (NEXT_INSN (x
)) == JUMP_INSN
2140 && (GET_CODE (PATTERN (NEXT_INSN (x
))) == ADDR_DIFF_VEC
2141 || GET_CODE (PATTERN (NEXT_INSN (x
))) == ADDR_VEC
))
2144 /* But in any case, non-deletable labels can appear anywhere. */
2148 fatal_insn ("insn outside basic block", x
);
2153 && GET_CODE (x
) == JUMP_INSN
2154 && returnjump_p (x
) && ! condjump_p (x
)
2155 && ! (NEXT_INSN (x
) && GET_CODE (NEXT_INSN (x
)) == BARRIER
))
2156 fatal_insn ("return not followed by barrier", x
);
2157 if (curr_bb
&& x
== curr_bb
->end
)
2161 if (num_bb_notes
!= n_basic_blocks
)
2163 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2164 num_bb_notes
, n_basic_blocks
);
2169 /* Assume that the preceding pass has possibly eliminated jump instructions
2170 or converted the unconditional jumps. Eliminate the edges from CFG.
2171 Return true if any edges are eliminated. */
2174 purge_dead_edges (basic_block bb
)
2177 rtx insn
= bb
->end
, note
;
2178 bool purged
= false;
2180 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2181 if (GET_CODE (insn
) == INSN
2182 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
2186 if (! may_trap_p (PATTERN (insn
))
2187 || ((eqnote
= find_reg_equal_equiv_note (insn
))
2188 && ! may_trap_p (XEXP (eqnote
, 0))))
2189 remove_note (insn
, note
);
2192 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2193 for (e
= bb
->succ
; e
; e
= next
)
2195 next
= e
->succ_next
;
2196 if (e
->flags
& EDGE_EH
)
2198 if (can_throw_internal (bb
->end
))
2201 else if (e
->flags
& EDGE_ABNORMAL_CALL
)
2203 if (GET_CODE (bb
->end
) == CALL_INSN
2204 && (! (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
))
2205 || INTVAL (XEXP (note
, 0)) >= 0))
2212 bb
->flags
|= BB_DIRTY
;
2216 if (GET_CODE (insn
) == JUMP_INSN
)
2221 /* We do care only about conditional jumps and simplejumps. */
2222 if (!any_condjump_p (insn
)
2223 && !returnjump_p (insn
)
2224 && !simplejump_p (insn
))
2227 /* Branch probability/prediction notes are defined only for
2228 condjumps. We've possibly turned condjump into simplejump. */
2229 if (simplejump_p (insn
))
2231 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2233 remove_note (insn
, note
);
2234 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
2235 remove_note (insn
, note
);
2238 for (e
= bb
->succ
; e
; e
= next
)
2240 next
= e
->succ_next
;
2242 /* Avoid abnormal flags to leak from computed jumps turned
2243 into simplejumps. */
2245 e
->flags
&= ~EDGE_ABNORMAL
;
2247 /* See if this edge is one we should keep. */
2248 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
2249 /* A conditional jump can fall through into the next
2250 block, so we should keep the edge. */
2252 else if (e
->dest
!= EXIT_BLOCK_PTR
2253 && e
->dest
->head
== JUMP_LABEL (insn
))
2254 /* If the destination block is the target of the jump,
2257 else if (e
->dest
== EXIT_BLOCK_PTR
&& returnjump_p (insn
))
2258 /* If the destination block is the exit block, and this
2259 instruction is a return, then keep the edge. */
2261 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2262 /* Keep the edges that correspond to exceptions thrown by
2263 this instruction. */
2266 /* We do not need this edge. */
2267 bb
->flags
|= BB_DIRTY
;
2272 if (!bb
->succ
|| !purged
)
2276 fprintf (rtl_dump_file
, "Purged edges from bb %i\n", bb
->index
);
2281 /* Redistribute probabilities. */
2282 if (!bb
->succ
->succ_next
)
2284 bb
->succ
->probability
= REG_BR_PROB_BASE
;
2285 bb
->succ
->count
= bb
->count
;
2289 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2293 b
= BRANCH_EDGE (bb
);
2294 f
= FALLTHRU_EDGE (bb
);
2295 b
->probability
= INTVAL (XEXP (note
, 0));
2296 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
2297 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
2298 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
2303 else if (GET_CODE (insn
) == CALL_INSN
&& SIBLING_CALL_P (insn
))
2305 /* First, there should not be any EH or ABCALL edges resulting
2306 from non-local gotos and the like. If there were, we shouldn't
2307 have created the sibcall in the first place. Second, there
2308 should of course never have been a fallthru edge. */
2309 if (!bb
->succ
|| bb
->succ
->succ_next
)
2311 if (bb
->succ
->flags
!= (EDGE_SIBCALL
| EDGE_ABNORMAL
))
2317 /* If we don't see a jump insn, we don't know exactly why the block would
2318 have been broken at this point. Look for a simple, non-fallthru edge,
2319 as these are only created by conditional branches. If we find such an
2320 edge we know that there used to be a jump here and can then safely
2321 remove all non-fallthru edges. */
2322 for (e
= bb
->succ
; e
&& (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
));
2329 for (e
= bb
->succ
; e
; e
= next
)
2331 next
= e
->succ_next
;
2332 if (!(e
->flags
& EDGE_FALLTHRU
))
2334 bb
->flags
|= BB_DIRTY
;
2340 if (!bb
->succ
|| bb
->succ
->succ_next
)
2343 bb
->succ
->probability
= REG_BR_PROB_BASE
;
2344 bb
->succ
->count
= bb
->count
;
2347 fprintf (rtl_dump_file
, "Purged non-fallthru edges from bb %i\n",
2352 /* Search all basic blocks for potentially dead edges and purge them. Return
2353 true if some edge has been eliminated. */
2356 purge_all_dead_edges (int update_life_p
)
2364 blocks
= sbitmap_alloc (last_basic_block
);
2365 sbitmap_zero (blocks
);
2370 bool purged_here
= purge_dead_edges (bb
);
2372 purged
|= purged_here
;
2373 if (purged_here
&& update_life_p
)
2374 SET_BIT (blocks
, bb
->index
);
2377 if (update_life_p
&& purged
)
2378 update_life_info (blocks
, UPDATE_LIFE_GLOBAL
,
2379 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2380 | PROP_KILL_DEAD_CODE
);
2383 sbitmap_free (blocks
);
2387 /* Same as split_block but update cfg_layout structures. */
2389 cfg_layout_split_block (basic_block bb
, void *insnp
)
2393 edge fallthru
= rtl_split_block (bb
, insn
);
2395 fallthru
->dest
->rbi
->footer
= fallthru
->src
->rbi
->footer
;
2396 fallthru
->src
->rbi
->footer
= NULL
;
2401 /* Redirect Edge to DEST. */
2403 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
2405 basic_block src
= e
->src
;
2408 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
2411 if (e
->src
!= ENTRY_BLOCK_PTR
2412 && try_redirect_by_replacing_jump (e
, dest
, true))
2415 if (e
->dest
== dest
)
2418 if (e
->src
== ENTRY_BLOCK_PTR
2419 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
2422 fprintf (rtl_dump_file
, "Redirecting entry edge from bb %i to %i\n",
2423 e
->src
->index
, dest
->index
);
2425 redirect_edge_succ (e
, dest
);
2429 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2430 in the case the basic block appears to be in sequence. Avoid this
2433 if (e
->flags
& EDGE_FALLTHRU
)
2435 /* Redirect any branch edges unified with the fallthru one. */
2436 if (GET_CODE (src
->end
) == JUMP_INSN
2437 && JUMP_LABEL (src
->end
) == e
->dest
->head
)
2439 if (!redirect_jump (src
->end
, block_label (dest
), 0))
2442 /* In case we are redirecting fallthru edge to the branch edge
2443 of conditional jump, remove it. */
2444 if (src
->succ
->succ_next
2445 && !src
->succ
->succ_next
->succ_next
)
2447 edge s
= e
->succ_next
? e
->succ_next
: src
->succ
;
2449 && any_condjump_p (src
->end
)
2450 && onlyjump_p (src
->end
))
2451 delete_insn (src
->end
);
2453 redirect_edge_succ_nodup (e
, dest
);
2455 fprintf (rtl_dump_file
, "Fallthru edge %i->%i redirected to %i\n",
2456 e
->src
->index
, e
->dest
->index
, dest
->index
);
2461 ret
= redirect_branch_edge (e
, dest
);
2463 /* We don't want simplejumps in the insn stream during cfglayout. */
2464 if (simplejump_p (src
->end
))
2470 /* Simple wrapper as we always can redirect fallthru edges. */
2472 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
2474 if (!cfg_layout_redirect_edge_and_branch (e
, dest
))
2479 /* Same as flow_delete_block but update cfg_layout structures. */
2481 cfg_layout_delete_block (basic_block bb
)
2483 rtx insn
, next
, prev
= PREV_INSN (bb
->head
), *to
, remaints
;
2485 if (bb
->rbi
->header
)
2489 NEXT_INSN (prev
) = bb
->rbi
->header
;
2491 set_first_insn (bb
->rbi
->header
);
2492 PREV_INSN (bb
->rbi
->header
) = prev
;
2493 insn
= bb
->rbi
->header
;
2494 while (NEXT_INSN (insn
))
2495 insn
= NEXT_INSN (insn
);
2496 NEXT_INSN (insn
) = next
;
2497 PREV_INSN (next
) = insn
;
2499 next
= NEXT_INSN (bb
->end
);
2500 if (bb
->rbi
->footer
)
2502 insn
= bb
->rbi
->footer
;
2505 if (GET_CODE (insn
) == BARRIER
)
2507 if (PREV_INSN (insn
))
2508 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2510 bb
->rbi
->footer
= NEXT_INSN (insn
);
2511 if (NEXT_INSN (insn
))
2512 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2514 if (GET_CODE (insn
) == CODE_LABEL
)
2516 insn
= NEXT_INSN (insn
);
2518 if (bb
->rbi
->footer
)
2521 NEXT_INSN (insn
) = bb
->rbi
->footer
;
2522 PREV_INSN (bb
->rbi
->footer
) = insn
;
2523 while (NEXT_INSN (insn
))
2524 insn
= NEXT_INSN (insn
);
2525 NEXT_INSN (insn
) = next
;
2527 PREV_INSN (next
) = insn
;
2529 set_last_insn (insn
);
2532 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2533 to
= &bb
->next_bb
->rbi
->header
;
2535 to
= &cfg_layout_function_footer
;
2536 rtl_delete_block (bb
);
2539 prev
= NEXT_INSN (prev
);
2541 prev
= get_insns ();
2543 next
= PREV_INSN (next
);
2545 next
= get_last_insn ();
2547 if (next
&& NEXT_INSN (next
) != prev
)
2549 remaints
= unlink_insn_chain (prev
, next
);
2551 while (NEXT_INSN (insn
))
2552 insn
= NEXT_INSN (insn
);
2553 NEXT_INSN (insn
) = *to
;
2555 PREV_INSN (*to
) = insn
;
2560 /* return true when blocks A and B can be safely merged. */
2562 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
2564 /* There must be exactly one edge in between the blocks. */
2565 return (a
->succ
&& !a
->succ
->succ_next
&& a
->succ
->dest
== b
2566 && !b
->pred
->pred_next
&& a
!= b
2567 /* Must be simple edge. */
2568 && !(a
->succ
->flags
& EDGE_COMPLEX
)
2569 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
2570 /* If the jump insn has side effects,
2571 we can't kill the edge. */
2572 && (GET_CODE (a
->end
) != JUMP_INSN
2574 ? simplejump_p (a
->end
) : onlyjump_p (a
->end
))));
2577 /* Merge block A and B, abort when it is not possible. */
2579 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
2581 #ifdef ENABLE_CHECKING
2582 if (!cfg_layout_can_merge_blocks_p (a
, b
))
2586 /* If there was a CODE_LABEL beginning B, delete it. */
2587 if (GET_CODE (b
->head
) == CODE_LABEL
)
2588 delete_insn (b
->head
);
2590 /* We should have fallthru edge in a, or we can do dummy redirection to get
2592 if (GET_CODE (a
->end
) == JUMP_INSN
)
2593 redirect_edge_and_branch (a
->succ
, b
);
2594 if (GET_CODE (a
->end
) == JUMP_INSN
)
2597 /* Possible line number notes should appear in between. */
2600 rtx first
= a
->end
, last
;
2602 last
= emit_insn_after (b
->rbi
->header
, a
->end
);
2603 delete_insn_chain (NEXT_INSN (first
), last
);
2604 b
->rbi
->header
= NULL
;
2607 /* In the case basic blocks are not adjacent, move them around. */
2608 if (NEXT_INSN (a
->end
) != b
->head
)
2610 rtx first
= unlink_insn_chain (b
->head
, b
->end
);
2612 emit_insn_after (first
, a
->end
);
2613 /* Skip possible DELETED_LABEL insn. */
2614 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2615 first
= NEXT_INSN (first
);
2616 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2619 delete_insn (first
);
2621 /* Otherwise just re-associate the instructions. */
2626 for (insn
= b
->head
; insn
!= NEXT_INSN (b
->end
); insn
= NEXT_INSN (insn
))
2627 set_block_for_insn (insn
, a
);
2629 /* Skip possible DELETED_LABEL insn. */
2630 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2631 insn
= NEXT_INSN (insn
);
2632 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2639 /* Possible tablejumps and barriers should appear after the block. */
2642 if (!a
->rbi
->footer
)
2643 a
->rbi
->footer
= b
->rbi
->footer
;
2646 rtx last
= a
->rbi
->footer
;
2648 while (NEXT_INSN (last
))
2649 last
= NEXT_INSN (last
);
2650 NEXT_INSN (last
) = b
->rbi
->footer
;
2651 PREV_INSN (b
->rbi
->footer
) = last
;
2653 b
->rbi
->footer
= NULL
;
2657 fprintf (rtl_dump_file
, "Merged blocks %d and %d.\n",
2658 a
->index
, b
->index
);
2660 update_cfg_after_block_merging (a
, b
);
2665 cfg_layout_split_edge (edge e
)
2668 basic_block new_bb
=
2669 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR
2670 ? NEXT_INSN (e
->src
-> end
) : get_insns (),
2673 new_bb
->count
= e
->count
;
2674 new_bb
->frequency
= EDGE_FREQUENCY (e
);
2676 new_e
= make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
2677 new_e
->probability
= REG_BR_PROB_BASE
;
2678 new_e
->count
= e
->count
;
2679 redirect_edge_and_branch_force (e
, new_bb
);
2684 /* Implementation of CFG manipulation for linearized RTL. */
2685 struct cfg_hooks rtl_cfg_hooks
= {
2686 rtl_verify_flow_info
,
2688 rtl_create_basic_block
,
2689 rtl_redirect_edge_and_branch
,
2690 rtl_redirect_edge_and_branch_force
,
2693 rtl_can_merge_blocks
, /* can_merge_blocks_p */
2698 /* Implementation of CFG manipulation for cfg layout RTL, where
2699 basic block connected via fallthru edges does not have to be adjacent.
2700 This representation will hopefully become the default one in future
2701 version of the compiler. */
2702 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
2703 rtl_verify_flow_info_1
,
2705 cfg_layout_create_basic_block
,
2706 cfg_layout_redirect_edge_and_branch
,
2707 cfg_layout_redirect_edge_and_branch_force
,
2708 cfg_layout_delete_block
,
2709 cfg_layout_split_block
,
2710 cfg_layout_can_merge_blocks_p
,
2711 cfg_layout_merge_blocks
,
2712 cfg_layout_split_edge