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, 2004 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 bool rtl_move_block_after (basic_block, basic_block);
80 static int rtl_verify_flow_info (void);
81 static basic_block cfg_layout_split_block (basic_block, void *);
82 static bool cfg_layout_redirect_edge_and_branch (edge, basic_block);
83 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
84 static void cfg_layout_delete_block (basic_block);
85 static void rtl_delete_block (basic_block);
86 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
87 static bool rtl_redirect_edge_and_branch (edge, basic_block);
88 static basic_block rtl_split_block (basic_block, void *);
89 static void rtl_dump_bb (basic_block, FILE *, int);
90 static int rtl_verify_flow_info_1 (void);
91 static void mark_killed_regs (rtx, rtx, void *);
92 static void rtl_make_forwarder_block (edge);
94 /* Return true if NOTE is not one of the ones that must be kept paired,
95 so that we may simply delete it. */
98 can_delete_note_p (rtx note)
100 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
101 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK
102 || NOTE_LINE_NUMBER (note) == NOTE_INSN_PREDICTION);
105 /* True if a given label can be deleted. */
108 can_delete_label_p (rtx label)
110 return (!LABEL_PRESERVE_P (label)
111 /* User declared labels must be preserved. */
112 && LABEL_NAME (label) == 0
113 && !in_expr_list_p (forced_labels, label)
114 && !in_expr_list_p (label_value_list, label));
117 /* Delete INSN by patching it out. Return the next insn. */
120 delete_insn (rtx insn)
122 rtx next = NEXT_INSN (insn);
124 bool really_delete = true;
126 if (GET_CODE (insn) == CODE_LABEL)
128 /* Some labels can't be directly removed from the INSN chain, as they
129 might be references via variables, constant pool etc.
130 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
131 if (! can_delete_label_p (insn))
133 const char *name = LABEL_NAME (insn);
135 really_delete = false;
136 PUT_CODE (insn, NOTE);
137 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
138 NOTE_SOURCE_FILE (insn) = name;
141 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
146 /* If this insn has already been deleted, something is very wrong. */
147 if (INSN_DELETED_P (insn))
150 INSN_DELETED_P (insn) = 1;
153 /* If deleting a jump, decrement the use count of the label. Deleting
154 the label itself should happen in the normal course of block merging. */
155 if (GET_CODE (insn) == JUMP_INSN
157 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
158 LABEL_NUSES (JUMP_LABEL (insn))--;
160 /* Also if deleting an insn that references a label. */
163 while ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
164 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
166 LABEL_NUSES (XEXP (note, 0))--;
167 remove_note (insn, note);
171 if (GET_CODE (insn) == JUMP_INSN
172 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
173 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
175 rtx pat = PATTERN (insn);
176 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
177 int len = XVECLEN (pat, diff_vec_p);
180 for (i = 0; i < len; i++)
182 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
184 /* When deleting code in bulk (e.g. removing many unreachable
185 blocks) we can delete a label that's a target of the vector
186 before deleting the vector itself. */
187 if (GET_CODE (label) != NOTE)
188 LABEL_NUSES (label)--;
195 /* Like delete_insn but also purge dead edges from BB. */
197 delete_insn_and_edges (rtx insn)
203 && BLOCK_FOR_INSN (insn)
204 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
206 x = delete_insn (insn);
208 purge_dead_edges (BLOCK_FOR_INSN (insn));
212 /* Unlink a chain of insns between START and FINISH, leaving notes
213 that must be paired. */
216 delete_insn_chain (rtx start, rtx finish)
220 /* Unchain the insns one by one. It would be quicker to delete all of these
221 with a single unchaining, rather than one at a time, but we need to keep
225 next = NEXT_INSN (start);
226 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
229 next = delete_insn (start);
237 /* Like delete_insn but also purge dead edges from BB. */
239 delete_insn_chain_and_edges (rtx first, rtx last)
244 && BLOCK_FOR_INSN (last)
245 && BB_END (BLOCK_FOR_INSN (last)) == last)
247 delete_insn_chain (first, last);
249 purge_dead_edges (BLOCK_FOR_INSN (last));
252 /* Create a new basic block consisting of the instructions between HEAD and END
253 inclusive. This function is designed to allow fast BB construction - reuses
254 the note and basic block struct in BB_NOTE, if any and do not grow
255 BASIC_BLOCK chain and should be used directly only by CFG construction code.
256 END can be NULL in to create new empty basic block before HEAD. Both END
257 and HEAD can be NULL to create basic block at the end of INSN chain.
258 AFTER is the basic block we should be put after. */
261 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
266 && ! RTX_INTEGRATED_P (bb_note)
267 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
270 /* If we found an existing note, thread it back onto the chain. */
274 if (GET_CODE (head) == CODE_LABEL)
278 after = PREV_INSN (head);
282 if (after != bb_note && NEXT_INSN (after) != bb_note)
283 reorder_insns_nobb (bb_note, bb_note, after);
287 /* Otherwise we must create a note and a basic block structure. */
293 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
294 else if (GET_CODE (head) == CODE_LABEL && end)
296 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
302 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
308 NOTE_BASIC_BLOCK (bb_note) = bb;
311 /* Always include the bb note in the block. */
312 if (NEXT_INSN (end) == bb_note)
317 bb->index = last_basic_block++;
319 link_block (bb, after);
320 BASIC_BLOCK (bb->index) = bb;
321 update_bb_for_insn (bb);
323 /* Tag the block so that we know it has been used when considering
324 other basic block notes. */
330 /* Create new basic block consisting of instructions in between HEAD and END
331 and place it to the BB chain after block AFTER. END can be NULL in to
332 create new empty basic block before HEAD. Both END and HEAD can be NULL to
333 create basic block at the end of INSN chain. */
336 rtl_create_basic_block (void *headp, void *endp, basic_block after)
338 rtx head = headp, end = endp;
341 /* Place the new block just after the end. */
342 VARRAY_GROW (basic_block_info, last_basic_block + 1);
346 bb = create_basic_block_structure (head, end, NULL, after);
352 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
354 basic_block newbb = rtl_create_basic_block (head, end, after);
356 cfg_layout_initialize_rbi (newbb);
360 /* Delete the insns in a (non-live) block. We physically delete every
361 non-deleted-note insn, and update the flow graph appropriately.
363 Return nonzero if we deleted an exception handler. */
365 /* ??? Preserving all such notes strikes me as wrong. It would be nice
366 to post-process the stream to remove empty blocks, loops, ranges, etc. */
369 rtl_delete_block (basic_block b)
373 /* If the head of this block is a CODE_LABEL, then it might be the
374 label for an exception handler which can't be reached.
376 We need to remove the label from the exception_handler_label list
377 and remove the associated NOTE_INSN_EH_REGION_BEG and
378 NOTE_INSN_EH_REGION_END notes. */
380 /* Get rid of all NOTE_INSN_PREDICTIONs and NOTE_INSN_LOOP_CONTs
381 hanging before the block. */
383 for (insn = PREV_INSN (BB_HEAD (b)); insn; insn = PREV_INSN (insn))
385 if (GET_CODE (insn) != NOTE)
387 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_PREDICTION
388 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
389 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
394 never_reached_warning (insn, BB_END (b));
396 if (GET_CODE (insn) == CODE_LABEL)
397 maybe_remove_eh_handler (insn);
399 /* Include any jump table following the basic block. */
401 if (tablejump_p (end, NULL, &tmp))
404 /* Include any barrier that may follow the basic block. */
405 tmp = next_nonnote_insn (end);
406 if (tmp && GET_CODE (tmp) == BARRIER)
409 /* Selectively delete the entire chain. */
411 delete_insn_chain (insn, end);
414 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
417 compute_bb_for_insn (void)
423 rtx end = BB_END (bb);
426 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
428 BLOCK_FOR_INSN (insn) = bb;
435 /* Release the basic_block_for_insn array. */
438 free_bb_for_insn (void)
441 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
442 if (GET_CODE (insn) != BARRIER)
443 BLOCK_FOR_INSN (insn) = NULL;
446 /* Update insns block within BB. */
449 update_bb_for_insn (basic_block bb)
453 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
455 if (GET_CODE (insn) != BARRIER)
456 set_block_for_insn (insn, bb);
457 if (insn == BB_END (bb))
462 /* Creates a new basic block just after basic block B by splitting
463 everything after specified instruction I. */
466 rtl_split_block (basic_block bb, void *insnp)
474 insn = first_insn_after_basic_block_note (bb);
477 insn = PREV_INSN (insn);
479 insn = get_last_insn ();
482 /* We probably should check type of the insn so that we do not create
483 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
485 if (insn == BB_END (bb))
486 emit_note_after (NOTE_INSN_DELETED, insn);
488 /* Create the new basic block. */
489 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
492 /* Redirect the outgoing edges. */
493 new_bb->succ = bb->succ;
495 for (e = new_bb->succ; e; e = e->succ_next)
498 if (bb->global_live_at_start)
500 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
501 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
502 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
504 /* We now have to calculate which registers are live at the end
505 of the split basic block and at the start of the new basic
506 block. Start with those registers that are known to be live
507 at the end of the original basic block and get
508 propagate_block to determine which registers are live. */
509 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
510 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
511 COPY_REG_SET (bb->global_live_at_end,
512 new_bb->global_live_at_start);
513 #ifdef HAVE_conditional_execution
514 /* In the presence of conditional execution we are not able to update
515 liveness precisely. */
516 if (reload_completed)
518 bb->flags |= BB_DIRTY;
519 new_bb->flags |= BB_DIRTY;
527 /* Blocks A and B are to be merged into a single block A. The insns
528 are already contiguous. */
531 rtl_merge_blocks (basic_block a, basic_block b)
533 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
534 rtx del_first = NULL_RTX, del_last = NULL_RTX;
537 /* If there was a CODE_LABEL beginning B, delete it. */
538 if (GET_CODE (b_head) == CODE_LABEL)
540 /* Detect basic blocks with nothing but a label. This can happen
541 in particular at the end of a function. */
545 del_first = del_last = b_head;
546 b_head = NEXT_INSN (b_head);
549 /* Delete the basic block note and handle blocks containing just that
551 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
559 b_head = NEXT_INSN (b_head);
562 /* If there was a jump out of A, delete it. */
563 if (GET_CODE (a_end) == JUMP_INSN)
567 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
568 if (GET_CODE (prev) != NOTE
569 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
570 || prev == BB_HEAD (a))
576 /* If this was a conditional jump, we need to also delete
577 the insn that set cc0. */
578 if (only_sets_cc0_p (prev))
582 prev = prev_nonnote_insn (prev);
589 a_end = PREV_INSN (del_first);
591 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
592 del_first = NEXT_INSN (a_end);
594 /* Delete everything marked above as well as crap that might be
595 hanging out between the two blocks. */
597 delete_insn_chain (del_first, del_last);
599 /* Reassociate the insns of B with A. */
604 for (x = a_end; x != b_end; x = NEXT_INSN (x))
605 set_block_for_insn (x, a);
607 set_block_for_insn (b_end, a);
615 /* Return true when block A and B can be merged. */
617 rtl_can_merge_blocks (basic_block a,basic_block b)
619 /* There must be exactly one edge in between the blocks. */
620 return (a->succ && !a->succ->succ_next && a->succ->dest == b
621 && !b->pred->pred_next && a != b
622 /* Must be simple edge. */
623 && !(a->succ->flags & EDGE_COMPLEX)
625 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
626 /* If the jump insn has side effects,
627 we can't kill the edge. */
628 && (GET_CODE (BB_END (a)) != JUMP_INSN
630 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
633 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
637 block_label (basic_block block)
639 if (block == EXIT_BLOCK_PTR)
642 if (GET_CODE (BB_HEAD (block)) != CODE_LABEL)
644 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
647 return BB_HEAD (block);
650 /* Attempt to perform edge redirection by replacing possibly complex jump
651 instruction by unconditional jump or removing jump completely. This can
652 apply only if all edges now point to the same block. The parameters and
653 return values are equivalent to redirect_edge_and_branch. */
656 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
658 basic_block src = e->src;
659 rtx insn = BB_END (src), kill_from;
664 /* Verify that all targets will be TARGET. */
665 for (tmp = src->succ; tmp; tmp = tmp->succ_next)
666 if (tmp->dest != target && tmp != e)
669 if (tmp || !onlyjump_p (insn))
671 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
674 /* Avoid removing branch with side effects. */
675 set = single_set (insn);
676 if (!set || side_effects_p (set))
679 /* In case we zap a conditional jump, we'll need to kill
680 the cc0 setter too. */
683 if (reg_mentioned_p (cc0_rtx, PATTERN (insn)))
684 kill_from = PREV_INSN (insn);
687 /* See if we can create the fallthru edge. */
688 if (in_cfglayout || can_fallthru (src, target))
691 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
694 /* Selectively unlink whole insn chain. */
697 rtx insn = src->rbi->footer;
699 delete_insn_chain (kill_from, BB_END (src));
701 /* Remove barriers but keep jumptables. */
704 if (GET_CODE (insn) == BARRIER)
706 if (PREV_INSN (insn))
707 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
709 src->rbi->footer = NEXT_INSN (insn);
710 if (NEXT_INSN (insn))
711 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
713 if (GET_CODE (insn) == CODE_LABEL)
715 insn = NEXT_INSN (insn);
719 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)));
722 /* If this already is simplejump, redirect it. */
723 else if (simplejump_p (insn))
725 if (e->dest == target)
728 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
729 INSN_UID (insn), e->dest->index, target->index);
730 if (!redirect_jump (insn, block_label (target), 0))
732 if (target == EXIT_BLOCK_PTR)
738 /* Cannot do anything for target exit block. */
739 else if (target == EXIT_BLOCK_PTR)
742 /* Or replace possibly complicated jump insn by simple jump insn. */
745 rtx target_label = block_label (target);
746 rtx barrier, label, table;
748 emit_jump_insn_after (gen_jump (target_label), insn);
749 JUMP_LABEL (BB_END (src)) = target_label;
750 LABEL_NUSES (target_label)++;
752 fprintf (dump_file, "Replacing insn %i by jump %i\n",
753 INSN_UID (insn), INSN_UID (BB_END (src)));
756 delete_insn_chain (kill_from, insn);
758 /* Recognize a tablejump that we are converting to a
759 simple jump and remove its associated CODE_LABEL
760 and ADDR_VEC or ADDR_DIFF_VEC. */
761 if (tablejump_p (insn, &label, &table))
762 delete_insn_chain (label, table);
764 barrier = next_nonnote_insn (BB_END (src));
765 if (!barrier || GET_CODE (barrier) != BARRIER)
766 emit_barrier_after (BB_END (src));
769 if (barrier != NEXT_INSN (BB_END (src)))
771 /* Move the jump before barrier so that the notes
772 which originally were or were created before jump table are
773 inside the basic block. */
774 rtx new_insn = BB_END (src);
777 for (tmp = NEXT_INSN (BB_END (src)); tmp != barrier;
778 tmp = NEXT_INSN (tmp))
779 set_block_for_insn (tmp, src);
781 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
782 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
784 NEXT_INSN (new_insn) = barrier;
785 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
787 PREV_INSN (new_insn) = PREV_INSN (barrier);
788 PREV_INSN (barrier) = new_insn;
793 /* Keep only one edge out and set proper flags. */
794 while (src->succ->succ_next)
795 remove_edge (src->succ);
798 e->flags = EDGE_FALLTHRU;
802 e->probability = REG_BR_PROB_BASE;
803 e->count = src->count;
805 /* We don't want a block to end on a line-number note since that has
806 the potential of changing the code between -g and not -g. */
807 while (GET_CODE (BB_END (e->src)) == NOTE
808 && NOTE_LINE_NUMBER (BB_END (e->src)) >= 0)
809 delete_insn (BB_END (e->src));
811 if (e->dest != target)
812 redirect_edge_succ (e, target);
817 /* Return last loop_beg note appearing after INSN, before start of next
818 basic block. Return INSN if there are no such notes.
820 When emitting jump to redirect a fallthru edge, it should always appear
821 after the LOOP_BEG notes, as loop optimizer expect loop to either start by
822 fallthru edge or jump following the LOOP_BEG note jumping to the loop exit
826 last_loop_beg_note (rtx insn)
830 for (insn = NEXT_INSN (insn); insn && GET_CODE (insn) == NOTE
831 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK;
832 insn = NEXT_INSN (insn))
833 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
839 /* Redirect edge representing branch of (un)conditional jump or tablejump. */
841 redirect_branch_edge (edge e, basic_block target)
844 rtx old_label = BB_HEAD (e->dest);
845 basic_block src = e->src;
846 rtx insn = BB_END (src);
848 /* We can only redirect non-fallthru edges of jump insn. */
849 if (e->flags & EDGE_FALLTHRU)
851 else if (GET_CODE (insn) != JUMP_INSN)
854 /* Recognize a tablejump and adjust all matching cases. */
855 if (tablejump_p (insn, NULL, &tmp))
859 rtx new_label = block_label (target);
861 if (target == EXIT_BLOCK_PTR)
863 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
864 vec = XVEC (PATTERN (tmp), 0);
866 vec = XVEC (PATTERN (tmp), 1);
868 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
869 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
871 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
872 --LABEL_NUSES (old_label);
873 ++LABEL_NUSES (new_label);
876 /* Handle casesi dispatch insns. */
877 if ((tmp = single_set (insn)) != NULL
878 && SET_DEST (tmp) == pc_rtx
879 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
880 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
881 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
883 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
885 --LABEL_NUSES (old_label);
886 ++LABEL_NUSES (new_label);
891 /* ?? We may play the games with moving the named labels from
892 one basic block to the other in case only one computed_jump is
894 if (computed_jump_p (insn)
895 /* A return instruction can't be redirected. */
896 || returnjump_p (insn))
899 /* If the insn doesn't go where we think, we're confused. */
900 if (JUMP_LABEL (insn) != old_label)
903 /* If the substitution doesn't succeed, die. This can happen
904 if the back end emitted unrecognizable instructions or if
905 target is exit block on some arches. */
906 if (!redirect_jump (insn, block_label (target), 0))
908 if (target == EXIT_BLOCK_PTR)
915 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
916 e->src->index, e->dest->index, target->index);
918 if (e->dest != target)
919 redirect_edge_succ_nodup (e, target);
923 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
924 expense of adding new instructions or reordering basic blocks.
926 Function can be also called with edge destination equivalent to the TARGET.
927 Then it should try the simplifications and do nothing if none is possible.
929 Return true if transformation succeeded. We still return false in case E
930 already destinated TARGET and we didn't managed to simplify instruction
934 rtl_redirect_edge_and_branch (edge e, basic_block target)
936 basic_block src = e->src;
938 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
941 if (e->dest == target)
944 if (try_redirect_by_replacing_jump (e, target, false))
946 src->flags |= BB_DIRTY;
950 if (!redirect_branch_edge (e, target))
953 src->flags |= BB_DIRTY;
957 /* Like force_nonfallthru below, but additionally performs redirection
958 Used by redirect_edge_and_branch_force. */
961 force_nonfallthru_and_redirect (edge e, basic_block target)
963 basic_block jump_block, new_bb = NULL, src = e->src;
966 int abnormal_edge_flags = 0;
968 /* In the case the last instruction is conditional jump to the next
969 instruction, first redirect the jump itself and then continue
970 by creating a basic block afterwards to redirect fallthru edge. */
971 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
972 && any_condjump_p (BB_END (e->src))
973 /* When called from cfglayout, fallthru edges do not
974 necessarily go to the next block. */
975 && e->src->next_bb == e->dest
976 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
979 edge b = unchecked_make_edge (e->src, target, 0);
981 if (!redirect_jump (BB_END (e->src), block_label (target), 0))
983 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
986 int prob = INTVAL (XEXP (note, 0));
988 b->probability = prob;
989 b->count = e->count * prob / REG_BR_PROB_BASE;
990 e->probability -= e->probability;
991 e->count -= b->count;
992 if (e->probability < 0)
999 if (e->flags & EDGE_ABNORMAL)
1001 /* Irritating special case - fallthru edge to the same block as abnormal
1003 We can't redirect abnormal edge, but we still can split the fallthru
1004 one and create separate abnormal edge to original destination.
1005 This allows bb-reorder to make such edge non-fallthru. */
1006 if (e->dest != target)
1008 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1009 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1011 else if (!(e->flags & EDGE_FALLTHRU))
1013 else if (e->src == ENTRY_BLOCK_PTR)
1015 /* We can't redirect the entry block. Create an empty block at the
1016 start of the function which we use to add the new jump. */
1018 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1020 /* Change the existing edge's source to be the new block, and add
1021 a new edge from the entry block to the new block. */
1023 for (pe1 = &ENTRY_BLOCK_PTR->succ; *pe1; pe1 = &(*pe1)->succ_next)
1026 *pe1 = e->succ_next;
1031 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1034 if (e->src->succ->succ_next || abnormal_edge_flags)
1036 /* Create the new structures. */
1038 /* If the old block ended with a tablejump, skip its table
1039 by searching forward from there. Otherwise start searching
1040 forward from the last instruction of the old block. */
1041 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1042 note = BB_END (e->src);
1044 /* Position the new block correctly relative to loop notes. */
1045 note = last_loop_beg_note (note);
1046 note = NEXT_INSN (note);
1048 jump_block = create_basic_block (note, NULL, e->src);
1049 jump_block->count = e->count;
1050 jump_block->frequency = EDGE_FREQUENCY (e);
1051 jump_block->loop_depth = target->loop_depth;
1053 if (target->global_live_at_start)
1055 jump_block->global_live_at_start
1056 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1057 jump_block->global_live_at_end
1058 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1059 COPY_REG_SET (jump_block->global_live_at_start,
1060 target->global_live_at_start);
1061 COPY_REG_SET (jump_block->global_live_at_end,
1062 target->global_live_at_start);
1066 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1067 new_edge->probability = e->probability;
1068 new_edge->count = e->count;
1070 /* Redirect old edge. */
1071 redirect_edge_pred (e, jump_block);
1072 e->probability = REG_BR_PROB_BASE;
1074 new_bb = jump_block;
1077 jump_block = e->src;
1079 e->flags &= ~EDGE_FALLTHRU;
1080 if (target == EXIT_BLOCK_PTR)
1083 emit_jump_insn_after (gen_return (), BB_END (jump_block));
1089 rtx label = block_label (target);
1090 emit_jump_insn_after (gen_jump (label), BB_END (jump_block));
1091 JUMP_LABEL (BB_END (jump_block)) = label;
1092 LABEL_NUSES (label)++;
1095 emit_barrier_after (BB_END (jump_block));
1096 redirect_edge_succ_nodup (e, target);
1098 if (abnormal_edge_flags)
1099 make_edge (src, target, abnormal_edge_flags);
1104 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1105 (and possibly create new basic block) to make edge non-fallthru.
1106 Return newly created BB or NULL if none. */
1109 force_nonfallthru (edge e)
1111 return force_nonfallthru_and_redirect (e, e->dest);
1114 /* Redirect edge even at the expense of creating new jump insn or
1115 basic block. Return new basic block if created, NULL otherwise.
1116 Abort if conversion is impossible. */
1119 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1121 if (redirect_edge_and_branch (e, target)
1122 || e->dest == target)
1125 /* In case the edge redirection failed, try to force it to be non-fallthru
1126 and redirect newly created simplejump. */
1127 return force_nonfallthru_and_redirect (e, target);
1130 /* The given edge should potentially be a fallthru edge. If that is in
1131 fact true, delete the jump and barriers that are in the way. */
1134 rtl_tidy_fallthru_edge (edge e)
1137 basic_block b = e->src, c = b->next_bb;
1139 /* ??? In a late-running flow pass, other folks may have deleted basic
1140 blocks by nopping out blocks, leaving multiple BARRIERs between here
1141 and the target label. They ought to be chastized and fixed.
1143 We can also wind up with a sequence of undeletable labels between
1144 one block and the next.
1146 So search through a sequence of barriers, labels, and notes for
1147 the head of block C and assert that we really do fall through. */
1149 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1153 /* Remove what will soon cease being the jump insn from the source block.
1154 If block B consisted only of this single jump, turn it into a deleted
1157 if (GET_CODE (q) == JUMP_INSN
1159 && (any_uncondjump_p (q)
1160 || (b->succ == e && e->succ_next == NULL)))
1163 /* If this was a conditional jump, we need to also delete
1164 the insn that set cc0. */
1165 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1171 /* We don't want a block to end on a line-number note since that has
1172 the potential of changing the code between -g and not -g. */
1173 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
1177 /* Selectively unlink the sequence. */
1178 if (q != PREV_INSN (BB_HEAD (c)))
1179 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)));
1181 e->flags |= EDGE_FALLTHRU;
1184 /* Helper function for split_edge. Return true in case edge BB2 to BB1
1185 is back edge of syntactic loop. */
1188 back_edge_of_syntactic_loop_p (basic_block bb1, basic_block bb2)
1197 /* ??? Could we guarantee that bb indices are monotone, so that we could
1198 just compare them? */
1199 for (bb = bb1; bb && bb != bb2; bb = bb->next_bb)
1205 for (insn = BB_END (bb1); insn != BB_HEAD (bb2) && count >= 0;
1206 insn = NEXT_INSN (insn))
1207 if (GET_CODE (insn) == NOTE)
1209 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1211 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1218 /* Should move basic block BB after basic block AFTER. NIY. */
1221 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1222 basic_block after ATTRIBUTE_UNUSED)
1227 /* Split a (typically critical) edge. Return the new block.
1228 Abort on abnormal edges.
1230 ??? The code generally expects to be called on critical edges.
1231 The case of a block ending in an unconditional jump to a
1232 block with multiple predecessors is not handled optimally. */
1235 rtl_split_edge (edge edge_in)
1240 /* Abnormal edges cannot be split. */
1241 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
1244 /* We are going to place the new block in front of edge destination.
1245 Avoid existence of fallthru predecessors. */
1246 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1250 for (e = edge_in->dest->pred; e; e = e->pred_next)
1251 if (e->flags & EDGE_FALLTHRU)
1255 force_nonfallthru (e);
1258 /* Create the basic block note.
1260 Where we place the note can have a noticeable impact on the generated
1261 code. Consider this cfg:
1271 If we need to insert an insn on the edge from block 0 to block 1,
1272 we want to ensure the instructions we insert are outside of any
1273 loop notes that physically sit between block 0 and block 1. Otherwise
1274 we confuse the loop optimizer into thinking the loop is a phony. */
1276 if (edge_in->dest != EXIT_BLOCK_PTR
1277 && PREV_INSN (BB_HEAD (edge_in->dest))
1278 && GET_CODE (PREV_INSN (BB_HEAD (edge_in->dest))) == NOTE
1279 && (NOTE_LINE_NUMBER (PREV_INSN (BB_HEAD (edge_in->dest)))
1280 == NOTE_INSN_LOOP_BEG)
1281 && !back_edge_of_syntactic_loop_p (edge_in->dest, edge_in->src))
1282 before = PREV_INSN (BB_HEAD (edge_in->dest));
1283 else if (edge_in->dest != EXIT_BLOCK_PTR)
1284 before = BB_HEAD (edge_in->dest);
1288 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1290 /* ??? This info is likely going to be out of date very soon. */
1291 if (edge_in->dest->global_live_at_start)
1293 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1294 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1295 COPY_REG_SET (bb->global_live_at_start,
1296 edge_in->dest->global_live_at_start);
1297 COPY_REG_SET (bb->global_live_at_end,
1298 edge_in->dest->global_live_at_start);
1301 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1303 /* For non-fallthru edges, we must adjust the predecessor's
1304 jump instruction to target our new block. */
1305 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1307 if (!redirect_edge_and_branch (edge_in, bb))
1311 redirect_edge_succ (edge_in, bb);
1316 /* Queue instructions for insertion on an edge between two basic blocks.
1317 The new instructions and basic blocks (if any) will not appear in the
1318 CFG until commit_edge_insertions is called. */
1321 insert_insn_on_edge (rtx pattern, edge e)
1323 /* We cannot insert instructions on an abnormal critical edge.
1324 It will be easier to find the culprit if we die now. */
1325 if ((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e))
1328 if (e->insns == NULL_RTX)
1331 push_to_sequence (e->insns);
1333 emit_insn (pattern);
1335 e->insns = get_insns ();
1339 /* Called from safe_insert_insn_on_edge through note_stores, marks live
1340 registers that are killed by the store. */
1342 mark_killed_regs (rtx reg, rtx set ATTRIBUTE_UNUSED, void *data)
1344 regset killed = data;
1347 if (GET_CODE (reg) == SUBREG)
1348 reg = SUBREG_REG (reg);
1351 regno = REGNO (reg);
1352 if (regno >= FIRST_PSEUDO_REGISTER)
1353 SET_REGNO_REG_SET (killed, regno);
1356 for (i = 0; i < (int) hard_regno_nregs[regno][GET_MODE (reg)]; i++)
1357 SET_REGNO_REG_SET (killed, regno + i);
1361 /* Similar to insert_insn_on_edge, tries to put INSN to edge E. Additionally
1362 it checks whether this will not clobber the registers that are live on the
1363 edge (i.e. it requires liveness information to be up-to-date) and if there
1364 are some, then it tries to save and restore them. Returns true if
1367 safe_insert_insn_on_edge (rtx insn, edge e)
1370 regset_head killed_head;
1371 regset killed = INITIALIZE_REG_SET (killed_head);
1372 rtx save_regs = NULL_RTX;
1373 int regno, noccmode;
1374 enum machine_mode mode;
1376 #ifdef AVOID_CCMODE_COPIES
1382 for (x = insn; x; x = NEXT_INSN (x))
1384 note_stores (PATTERN (x), mark_killed_regs, killed);
1385 bitmap_operation (killed, killed, e->dest->global_live_at_start,
1388 EXECUTE_IF_SET_IN_REG_SET (killed, 0, regno,
1390 mode = regno < FIRST_PSEUDO_REGISTER
1391 ? reg_raw_mode[regno]
1392 : GET_MODE (regno_reg_rtx[regno]);
1393 if (mode == VOIDmode)
1396 if (noccmode && mode == CCmode)
1399 save_regs = alloc_EXPR_LIST (0,
1402 gen_raw_REG (mode, regno)),
1411 for (x = save_regs; x; x = XEXP (x, 1))
1413 from = XEXP (XEXP (x, 0), 1);
1414 to = XEXP (XEXP (x, 0), 0);
1415 emit_move_insn (to, from);
1418 for (x = save_regs; x; x = XEXP (x, 1))
1420 from = XEXP (XEXP (x, 0), 0);
1421 to = XEXP (XEXP (x, 0), 1);
1422 emit_move_insn (to, from);
1424 insn = get_insns ();
1426 free_EXPR_LIST_list (&save_regs);
1428 insert_insn_on_edge (insn, e);
1430 FREE_REG_SET (killed);
1434 /* Update the CFG for the instructions queued on edge E. */
1437 commit_one_edge_insertion (edge e, int watch_calls)
1439 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1440 basic_block bb = NULL;
1442 /* Pull the insns off the edge now since the edge might go away. */
1444 e->insns = NULL_RTX;
1446 /* Special case -- avoid inserting code between call and storing
1447 its return value. */
1448 if (watch_calls && (e->flags & EDGE_FALLTHRU) && !e->dest->pred->pred_next
1449 && e->src != ENTRY_BLOCK_PTR
1450 && GET_CODE (BB_END (e->src)) == CALL_INSN)
1452 rtx next = next_nonnote_insn (BB_END (e->src));
1454 after = BB_HEAD (e->dest);
1455 /* The first insn after the call may be a stack pop, skip it. */
1457 && keep_with_call_p (next))
1460 next = next_nonnote_insn (next);
1464 if (!before && !after)
1466 /* Figure out where to put these things. If the destination has
1467 one predecessor, insert there. Except for the exit block. */
1468 if (e->dest->pred->pred_next == NULL && e->dest != EXIT_BLOCK_PTR)
1472 /* Get the location correct wrt a code label, and "nice" wrt
1473 a basic block note, and before everything else. */
1475 if (GET_CODE (tmp) == CODE_LABEL)
1476 tmp = NEXT_INSN (tmp);
1477 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1478 tmp = NEXT_INSN (tmp);
1479 if (tmp == BB_HEAD (bb))
1482 after = PREV_INSN (tmp);
1484 after = get_last_insn ();
1487 /* If the source has one successor and the edge is not abnormal,
1488 insert there. Except for the entry block. */
1489 else if ((e->flags & EDGE_ABNORMAL) == 0
1490 && e->src->succ->succ_next == NULL
1491 && e->src != ENTRY_BLOCK_PTR)
1495 /* It is possible to have a non-simple jump here. Consider a target
1496 where some forms of unconditional jumps clobber a register. This
1497 happens on the fr30 for example.
1499 We know this block has a single successor, so we can just emit
1500 the queued insns before the jump. */
1501 if (GET_CODE (BB_END (bb)) == JUMP_INSN)
1502 for (before = BB_END (bb);
1503 GET_CODE (PREV_INSN (before)) == NOTE
1504 && NOTE_LINE_NUMBER (PREV_INSN (before)) ==
1505 NOTE_INSN_LOOP_BEG; before = PREV_INSN (before))
1509 /* We'd better be fallthru, or we've lost track of what's what. */
1510 if ((e->flags & EDGE_FALLTHRU) == 0)
1513 after = BB_END (bb);
1516 /* Otherwise we must split the edge. */
1519 bb = split_edge (e);
1520 after = BB_END (bb);
1524 /* Now that we've found the spot, do the insertion. */
1528 emit_insn_before (insns, before);
1529 last = prev_nonnote_insn (before);
1532 last = emit_insn_after (insns, after);
1534 if (returnjump_p (last))
1536 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1537 This is not currently a problem because this only happens
1538 for the (single) epilogue, which already has a fallthru edge
1542 if (e->dest != EXIT_BLOCK_PTR
1543 || e->succ_next != NULL || (e->flags & EDGE_FALLTHRU) == 0)
1546 e->flags &= ~EDGE_FALLTHRU;
1547 emit_barrier_after (last);
1550 delete_insn (before);
1552 else if (GET_CODE (last) == JUMP_INSN)
1555 /* Mark the basic block for find_sub_basic_blocks. */
1559 /* Update the CFG for all queued instructions. */
1562 commit_edge_insertions (void)
1566 bool changed = false;
1568 #ifdef ENABLE_CHECKING
1569 verify_flow_info ();
1572 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1576 for (e = bb->succ; e; e = next)
1578 next = e->succ_next;
1582 commit_one_edge_insertion (e, false);
1590 blocks = sbitmap_alloc (last_basic_block);
1591 sbitmap_zero (blocks);
1595 SET_BIT (blocks, bb->index);
1596 /* Check for forgotten bb->aux values before commit_edge_insertions
1598 if (bb->aux != &bb->aux)
1602 find_many_sub_basic_blocks (blocks);
1603 sbitmap_free (blocks);
1606 /* Update the CFG for all queued instructions, taking special care of inserting
1607 code on edges between call and storing its return value. */
1610 commit_edge_insertions_watch_calls (void)
1614 bool changed = false;
1616 #ifdef ENABLE_CHECKING
1617 verify_flow_info ();
1620 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1624 for (e = bb->succ; e; e = next)
1626 next = e->succ_next;
1630 commit_one_edge_insertion (e, true);
1638 blocks = sbitmap_alloc (last_basic_block);
1639 sbitmap_zero (blocks);
1643 SET_BIT (blocks, bb->index);
1644 /* Check for forgotten bb->aux values before commit_edge_insertions
1646 if (bb->aux != &bb->aux)
1650 find_many_sub_basic_blocks (blocks);
1651 sbitmap_free (blocks);
1654 /* Print out RTL-specific basic block information (live information
1655 at start and end). */
1658 rtl_dump_bb (basic_block bb, FILE *outf, int indent)
1664 s_indent = (char *) alloca ((size_t) indent + 1);
1665 memset ((void *) s_indent, ' ', (size_t) indent);
1666 s_indent[indent] = '\0';
1668 fprintf (outf, ";;%s Registers live at start: ", s_indent);
1669 dump_regset (bb->global_live_at_start, outf);
1672 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1673 insn = NEXT_INSN (insn))
1674 print_rtl_single (outf, insn);
1676 fprintf (outf, ";;%s Registers live at end: ", s_indent);
1677 dump_regset (bb->global_live_at_end, outf);
1681 /* Like print_rtl, but also print out live information for the start of each
1685 print_rtl_with_bb (FILE *outf, rtx rtx_first)
1690 fprintf (outf, "(nil)\n");
1693 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1694 int max_uid = get_max_uid ();
1695 basic_block *start = xcalloc (max_uid, sizeof (basic_block));
1696 basic_block *end = xcalloc (max_uid, sizeof (basic_block));
1697 enum bb_state *in_bb_p = xcalloc (max_uid, sizeof (enum bb_state));
1701 FOR_EACH_BB_REVERSE (bb)
1705 start[INSN_UID (BB_HEAD (bb))] = bb;
1706 end[INSN_UID (BB_END (bb))] = bb;
1707 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1709 enum bb_state state = IN_MULTIPLE_BB;
1711 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1713 in_bb_p[INSN_UID (x)] = state;
1715 if (x == BB_END (bb))
1720 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1724 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1726 fprintf (outf, ";; Start of basic block %d, registers live:",
1728 dump_regset (bb->global_live_at_start, outf);
1732 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1733 && GET_CODE (tmp_rtx) != NOTE
1734 && GET_CODE (tmp_rtx) != BARRIER)
1735 fprintf (outf, ";; Insn is not within a basic block\n");
1736 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1737 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1739 did_output = print_rtl_single (outf, tmp_rtx);
1741 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1743 fprintf (outf, ";; End of basic block %d, registers live:\n",
1745 dump_regset (bb->global_live_at_end, outf);
1758 if (current_function_epilogue_delay_list != 0)
1760 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1761 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
1762 tmp_rtx = XEXP (tmp_rtx, 1))
1763 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1768 update_br_prob_note (basic_block bb)
1771 if (GET_CODE (BB_END (bb)) != JUMP_INSN)
1773 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1774 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1776 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1779 /* Verify the CFG and RTL consistency common for both underlying RTL and
1782 Currently it does following checks:
1784 - test head/end pointers
1785 - overlapping of basic blocks
1786 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1787 - tails of basic blocks (ensure that boundary is necessary)
1788 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1789 and NOTE_INSN_BASIC_BLOCK
1791 In future it can be extended check a lot of other stuff as well
1792 (reachability of basic blocks, life information, etc. etc.). */
1795 rtl_verify_flow_info_1 (void)
1797 const int max_uid = get_max_uid ();
1798 rtx last_head = get_last_insn ();
1799 basic_block *bb_info;
1802 basic_block bb, last_bb_seen;
1804 bb_info = xcalloc (max_uid, sizeof (basic_block));
1806 /* Check bb chain & numbers. */
1807 last_bb_seen = ENTRY_BLOCK_PTR;
1809 FOR_EACH_BB_REVERSE (bb)
1811 rtx head = BB_HEAD (bb);
1812 rtx end = BB_END (bb);
1814 /* Verify the end of the basic block is in the INSN chain. */
1815 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1821 error ("end insn %d for block %d not found in the insn stream",
1822 INSN_UID (end), bb->index);
1826 /* Work backwards from the end to the head of the basic block
1827 to verify the head is in the RTL chain. */
1828 for (; x != NULL_RTX; x = PREV_INSN (x))
1830 /* While walking over the insn chain, verify insns appear
1831 in only one basic block and initialize the BB_INFO array
1832 used by other passes. */
1833 if (bb_info[INSN_UID (x)] != NULL)
1835 error ("insn %d is in multiple basic blocks (%d and %d)",
1836 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
1840 bb_info[INSN_UID (x)] = bb;
1847 error ("head insn %d for block %d not found in the insn stream",
1848 INSN_UID (head), bb->index);
1855 /* Now check the basic blocks (boundaries etc.) */
1856 FOR_EACH_BB_REVERSE (bb)
1858 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1859 edge e, fallthru = NULL;
1862 if (INSN_P (BB_END (bb))
1863 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1864 && bb->succ && bb->succ->succ_next
1865 && any_condjump_p (BB_END (bb)))
1867 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability)
1869 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1870 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1874 for (e = bb->succ; e; e = e->succ_next)
1876 if (e->flags & EDGE_FALLTHRU)
1877 n_fallthru++, fallthru = e;
1879 if ((e->flags & ~(EDGE_DFS_BACK
1881 | EDGE_IRREDUCIBLE_LOOP
1882 | EDGE_LOOP_EXIT)) == 0)
1885 if (e->flags & EDGE_ABNORMAL_CALL)
1888 if (e->flags & EDGE_EH)
1890 else if (e->flags & EDGE_ABNORMAL)
1894 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
1895 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1897 error ("Missing REG_EH_REGION note in the end of bb %i", bb->index);
1901 && (GET_CODE (BB_END (bb)) != JUMP_INSN
1902 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1903 || any_condjump_p (BB_END (bb))))))
1905 error ("Too many outgoing branch edges from bb %i", bb->index);
1908 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1910 error ("Fallthru edge after unconditional jump %i", bb->index);
1913 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1915 error ("Wrong amount of branch edges after unconditional jump %i", bb->index);
1918 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1919 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1921 error ("Wrong amount of branch edges after conditional jump %i", bb->index);
1924 if (n_call && GET_CODE (BB_END (bb)) != CALL_INSN)
1926 error ("Call edges for non-call insn in bb %i", bb->index);
1930 && (GET_CODE (BB_END (bb)) != CALL_INSN && n_call != n_abnormal)
1931 && (GET_CODE (BB_END (bb)) != JUMP_INSN
1932 || any_condjump_p (BB_END (bb))
1933 || any_uncondjump_p (BB_END (bb))))
1935 error ("Abnormal edges for no purpose in bb %i", bb->index);
1939 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
1940 if (BLOCK_FOR_INSN (x) != bb)
1943 if (! BLOCK_FOR_INSN (x))
1945 ("insn %d inside basic block %d but block_for_insn is NULL",
1946 INSN_UID (x), bb->index);
1949 ("insn %d inside basic block %d but block_for_insn is %i",
1950 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
1955 /* OK pointers are correct. Now check the header of basic
1956 block. It ought to contain optional CODE_LABEL followed
1957 by NOTE_BASIC_BLOCK. */
1959 if (GET_CODE (x) == CODE_LABEL)
1961 if (BB_END (bb) == x)
1963 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1971 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
1973 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1978 if (BB_END (bb) == x)
1979 /* Do checks for empty blocks her. e */
1982 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
1984 if (NOTE_INSN_BASIC_BLOCK_P (x))
1986 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
1987 INSN_UID (x), bb->index);
1991 if (x == BB_END (bb))
1994 if (control_flow_insn_p (x))
1996 error ("in basic block %d:", bb->index);
1997 fatal_insn ("flow control insn inside a basic block", x);
2007 /* Verify the CFG and RTL consistency common for both underlying RTL and
2010 Currently it does following checks:
2011 - all checks of rtl_verify_flow_info_1
2012 - check that all insns are in the basic blocks
2013 (except the switch handling code, barriers and notes)
2014 - check that all returns are followed by barriers
2015 - check that all fallthru edge points to the adjacent blocks. */
2017 rtl_verify_flow_info (void)
2020 int err = rtl_verify_flow_info_1 ();
2023 const rtx rtx_first = get_insns ();
2024 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2026 FOR_EACH_BB_REVERSE (bb)
2029 for (e = bb->succ; e; e = e->succ_next)
2030 if (e->flags & EDGE_FALLTHRU)
2036 /* Ensure existence of barrier in BB with no fallthru edges. */
2037 for (insn = BB_END (bb); !insn || GET_CODE (insn) != BARRIER;
2038 insn = NEXT_INSN (insn))
2040 || (GET_CODE (insn) == NOTE
2041 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK))
2043 error ("missing barrier after block %i", bb->index);
2048 else if (e->src != ENTRY_BLOCK_PTR
2049 && e->dest != EXIT_BLOCK_PTR)
2053 if (e->src->next_bb != e->dest)
2056 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2057 e->src->index, e->dest->index);
2061 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2062 insn = NEXT_INSN (insn))
2063 if (GET_CODE (insn) == BARRIER
2064 #ifndef CASE_DROPS_THROUGH
2067 || (INSN_P (insn) && ! JUMP_TABLE_DATA_P (insn))
2071 error ("verify_flow_info: Incorrect fallthru %i->%i",
2072 e->src->index, e->dest->index);
2073 fatal_insn ("wrong insn in the fallthru edge", insn);
2080 last_bb_seen = ENTRY_BLOCK_PTR;
2082 for (x = rtx_first; x; x = NEXT_INSN (x))
2084 if (NOTE_INSN_BASIC_BLOCK_P (x))
2086 bb = NOTE_BASIC_BLOCK (x);
2089 if (bb != last_bb_seen->next_bb)
2090 internal_error ("basic blocks not laid down consecutively");
2092 curr_bb = last_bb_seen = bb;
2097 switch (GET_CODE (x))
2104 /* An addr_vec is placed outside any block block. */
2106 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
2107 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2108 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2111 /* But in any case, non-deletable labels can appear anywhere. */
2115 fatal_insn ("insn outside basic block", x);
2120 && GET_CODE (x) == JUMP_INSN
2121 && returnjump_p (x) && ! condjump_p (x)
2122 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
2123 fatal_insn ("return not followed by barrier", x);
2124 if (curr_bb && x == BB_END (curr_bb))
2128 if (num_bb_notes != n_basic_blocks)
2130 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2131 num_bb_notes, n_basic_blocks);
2136 /* Assume that the preceding pass has possibly eliminated jump instructions
2137 or converted the unconditional jumps. Eliminate the edges from CFG.
2138 Return true if any edges are eliminated. */
2141 purge_dead_edges (basic_block bb)
2144 rtx insn = BB_END (bb), note;
2145 bool purged = false;
2147 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2148 if (GET_CODE (insn) == INSN
2149 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2153 if (! may_trap_p (PATTERN (insn))
2154 || ((eqnote = find_reg_equal_equiv_note (insn))
2155 && ! may_trap_p (XEXP (eqnote, 0))))
2156 remove_note (insn, note);
2159 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2160 for (e = bb->succ; e; e = next)
2162 next = e->succ_next;
2163 if (e->flags & EDGE_EH)
2165 if (can_throw_internal (BB_END (bb)))
2168 else if (e->flags & EDGE_ABNORMAL_CALL)
2170 if (GET_CODE (BB_END (bb)) == CALL_INSN
2171 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2172 || INTVAL (XEXP (note, 0)) >= 0))
2179 bb->flags |= BB_DIRTY;
2183 if (GET_CODE (insn) == JUMP_INSN)
2188 /* We do care only about conditional jumps and simplejumps. */
2189 if (!any_condjump_p (insn)
2190 && !returnjump_p (insn)
2191 && !simplejump_p (insn))
2194 /* Branch probability/prediction notes are defined only for
2195 condjumps. We've possibly turned condjump into simplejump. */
2196 if (simplejump_p (insn))
2198 note = find_reg_note (insn, REG_BR_PROB, NULL);
2200 remove_note (insn, note);
2201 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2202 remove_note (insn, note);
2205 for (e = bb->succ; e; e = next)
2207 next = e->succ_next;
2209 /* Avoid abnormal flags to leak from computed jumps turned
2210 into simplejumps. */
2212 e->flags &= ~EDGE_ABNORMAL;
2214 /* See if this edge is one we should keep. */
2215 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2216 /* A conditional jump can fall through into the next
2217 block, so we should keep the edge. */
2219 else if (e->dest != EXIT_BLOCK_PTR
2220 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2221 /* If the destination block is the target of the jump,
2224 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2225 /* If the destination block is the exit block, and this
2226 instruction is a return, then keep the edge. */
2228 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2229 /* Keep the edges that correspond to exceptions thrown by
2230 this instruction and rematerialize the EDGE_ABNORMAL
2231 flag we just cleared above. */
2233 e->flags |= EDGE_ABNORMAL;
2237 /* We do not need this edge. */
2238 bb->flags |= BB_DIRTY;
2243 if (!bb->succ || !purged)
2247 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2252 /* Redistribute probabilities. */
2253 if (!bb->succ->succ_next)
2255 bb->succ->probability = REG_BR_PROB_BASE;
2256 bb->succ->count = bb->count;
2260 note = find_reg_note (insn, REG_BR_PROB, NULL);
2264 b = BRANCH_EDGE (bb);
2265 f = FALLTHRU_EDGE (bb);
2266 b->probability = INTVAL (XEXP (note, 0));
2267 f->probability = REG_BR_PROB_BASE - b->probability;
2268 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2269 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2274 else if (GET_CODE (insn) == CALL_INSN && SIBLING_CALL_P (insn))
2276 /* First, there should not be any EH or ABCALL edges resulting
2277 from non-local gotos and the like. If there were, we shouldn't
2278 have created the sibcall in the first place. Second, there
2279 should of course never have been a fallthru edge. */
2280 if (!bb->succ || bb->succ->succ_next)
2282 if (bb->succ->flags != (EDGE_SIBCALL | EDGE_ABNORMAL))
2288 /* If we don't see a jump insn, we don't know exactly why the block would
2289 have been broken at this point. Look for a simple, non-fallthru edge,
2290 as these are only created by conditional branches. If we find such an
2291 edge we know that there used to be a jump here and can then safely
2292 remove all non-fallthru edges. */
2293 for (e = bb->succ; e && (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU));
2300 for (e = bb->succ; e; e = next)
2302 next = e->succ_next;
2303 if (!(e->flags & EDGE_FALLTHRU))
2305 bb->flags |= BB_DIRTY;
2311 if (!bb->succ || bb->succ->succ_next)
2314 bb->succ->probability = REG_BR_PROB_BASE;
2315 bb->succ->count = bb->count;
2318 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2323 /* Search all basic blocks for potentially dead edges and purge them. Return
2324 true if some edge has been eliminated. */
2327 purge_all_dead_edges (int update_life_p)
2335 blocks = sbitmap_alloc (last_basic_block);
2336 sbitmap_zero (blocks);
2341 bool purged_here = purge_dead_edges (bb);
2343 purged |= purged_here;
2344 if (purged_here && update_life_p)
2345 SET_BIT (blocks, bb->index);
2348 if (update_life_p && purged)
2349 update_life_info (blocks, UPDATE_LIFE_GLOBAL,
2350 PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE
2351 | PROP_KILL_DEAD_CODE);
2354 sbitmap_free (blocks);
2358 /* Same as split_block but update cfg_layout structures. */
2361 cfg_layout_split_block (basic_block bb, void *insnp)
2364 basic_block new_bb = rtl_split_block (bb, insn);
2366 new_bb->rbi->footer = bb->rbi->footer;
2367 bb->rbi->footer = NULL;
2373 /* Redirect Edge to DEST. */
2375 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2377 basic_block src = e->src;
2380 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2383 if (e->dest == dest)
2386 if (e->src != ENTRY_BLOCK_PTR
2387 && try_redirect_by_replacing_jump (e, dest, true))
2389 src->flags |= BB_DIRTY;
2393 if (e->src == ENTRY_BLOCK_PTR
2394 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2397 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2398 e->src->index, dest->index);
2400 e->src->flags |= BB_DIRTY;
2401 redirect_edge_succ (e, dest);
2405 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2406 in the case the basic block appears to be in sequence. Avoid this
2409 if (e->flags & EDGE_FALLTHRU)
2411 /* Redirect any branch edges unified with the fallthru one. */
2412 if (GET_CODE (BB_END (src)) == JUMP_INSN
2413 && label_is_jump_target_p (BB_HEAD (e->dest),
2417 fprintf (dump_file, "Fallthru edge unified with branch "
2418 "%i->%i redirected to %i\n",
2419 e->src->index, e->dest->index, dest->index);
2420 e->flags &= ~EDGE_FALLTHRU;
2421 if (!redirect_branch_edge (e, dest))
2423 e->flags |= EDGE_FALLTHRU;
2424 e->src->flags |= BB_DIRTY;
2427 /* In case we are redirecting fallthru edge to the branch edge
2428 of conditional jump, remove it. */
2429 if (src->succ->succ_next
2430 && !src->succ->succ_next->succ_next)
2432 edge s = e->succ_next ? e->succ_next : src->succ;
2434 && any_condjump_p (BB_END (src))
2435 && onlyjump_p (BB_END (src)))
2436 delete_insn (BB_END (src));
2438 redirect_edge_succ_nodup (e, dest);
2440 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2441 e->src->index, e->dest->index, dest->index);
2446 ret = redirect_branch_edge (e, dest);
2448 /* We don't want simplejumps in the insn stream during cfglayout. */
2449 if (simplejump_p (BB_END (src)))
2452 src->flags |= BB_DIRTY;
2456 /* Simple wrapper as we always can redirect fallthru edges. */
2458 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2460 if (!cfg_layout_redirect_edge_and_branch (e, dest))
2465 /* Same as delete_basic_block but update cfg_layout structures. */
2468 cfg_layout_delete_block (basic_block bb)
2470 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2472 if (bb->rbi->header)
2474 next = BB_HEAD (bb);
2476 NEXT_INSN (prev) = bb->rbi->header;
2478 set_first_insn (bb->rbi->header);
2479 PREV_INSN (bb->rbi->header) = prev;
2480 insn = bb->rbi->header;
2481 while (NEXT_INSN (insn))
2482 insn = NEXT_INSN (insn);
2483 NEXT_INSN (insn) = next;
2484 PREV_INSN (next) = insn;
2486 next = NEXT_INSN (BB_END (bb));
2487 if (bb->rbi->footer)
2489 insn = bb->rbi->footer;
2492 if (GET_CODE (insn) == BARRIER)
2494 if (PREV_INSN (insn))
2495 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2497 bb->rbi->footer = NEXT_INSN (insn);
2498 if (NEXT_INSN (insn))
2499 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2501 if (GET_CODE (insn) == CODE_LABEL)
2503 insn = NEXT_INSN (insn);
2505 if (bb->rbi->footer)
2508 NEXT_INSN (insn) = bb->rbi->footer;
2509 PREV_INSN (bb->rbi->footer) = insn;
2510 while (NEXT_INSN (insn))
2511 insn = NEXT_INSN (insn);
2512 NEXT_INSN (insn) = next;
2514 PREV_INSN (next) = insn;
2516 set_last_insn (insn);
2519 if (bb->next_bb != EXIT_BLOCK_PTR)
2520 to = &bb->next_bb->rbi->header;
2522 to = &cfg_layout_function_footer;
2523 rtl_delete_block (bb);
2526 prev = NEXT_INSN (prev);
2528 prev = get_insns ();
2530 next = PREV_INSN (next);
2532 next = get_last_insn ();
2534 if (next && NEXT_INSN (next) != prev)
2536 remaints = unlink_insn_chain (prev, next);
2538 while (NEXT_INSN (insn))
2539 insn = NEXT_INSN (insn);
2540 NEXT_INSN (insn) = *to;
2542 PREV_INSN (*to) = insn;
2547 /* Return true when blocks A and B can be safely merged. */
2549 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2551 /* There must be exactly one edge in between the blocks. */
2552 return (a->succ && !a->succ->succ_next && a->succ->dest == b
2553 && !b->pred->pred_next && a != b
2554 /* Must be simple edge. */
2555 && !(a->succ->flags & EDGE_COMPLEX)
2556 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2557 /* If the jump insn has side effects,
2558 we can't kill the edge. */
2559 && (GET_CODE (BB_END (a)) != JUMP_INSN
2560 || (reload_completed
2561 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2564 /* Merge block A and B, abort when it is not possible. */
2566 cfg_layout_merge_blocks (basic_block a, basic_block b)
2568 #ifdef ENABLE_CHECKING
2569 if (!cfg_layout_can_merge_blocks_p (a, b))
2573 /* If there was a CODE_LABEL beginning B, delete it. */
2574 if (GET_CODE (BB_HEAD (b)) == CODE_LABEL)
2575 delete_insn (BB_HEAD (b));
2577 /* We should have fallthru edge in a, or we can do dummy redirection to get
2579 if (GET_CODE (BB_END (a)) == JUMP_INSN)
2580 try_redirect_by_replacing_jump (a->succ, b, true);
2581 if (GET_CODE (BB_END (a)) == JUMP_INSN)
2584 /* Possible line number notes should appear in between. */
2587 rtx first = BB_END (a), last;
2589 last = emit_insn_after (b->rbi->header, BB_END (a));
2590 delete_insn_chain (NEXT_INSN (first), last);
2591 b->rbi->header = NULL;
2594 /* In the case basic blocks are not adjacent, move them around. */
2595 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2597 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2599 emit_insn_after (first, BB_END (a));
2600 /* Skip possible DELETED_LABEL insn. */
2601 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2602 first = NEXT_INSN (first);
2603 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2606 delete_insn (first);
2608 /* Otherwise just re-associate the instructions. */
2613 for (insn = BB_HEAD (b);
2614 insn != NEXT_INSN (BB_END (b));
2615 insn = NEXT_INSN (insn))
2616 set_block_for_insn (insn, a);
2618 /* Skip possible DELETED_LABEL insn. */
2619 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2620 insn = NEXT_INSN (insn);
2621 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2624 BB_END (a) = BB_END (b);
2628 /* Possible tablejumps and barriers should appear after the block. */
2631 if (!a->rbi->footer)
2632 a->rbi->footer = b->rbi->footer;
2635 rtx last = a->rbi->footer;
2637 while (NEXT_INSN (last))
2638 last = NEXT_INSN (last);
2639 NEXT_INSN (last) = b->rbi->footer;
2640 PREV_INSN (b->rbi->footer) = last;
2642 b->rbi->footer = NULL;
2646 fprintf (dump_file, "Merged blocks %d and %d.\n",
2647 a->index, b->index);
2653 cfg_layout_split_edge (edge e)
2656 basic_block new_bb =
2657 create_basic_block (e->src != ENTRY_BLOCK_PTR
2658 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2661 new_e = make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2662 redirect_edge_and_branch_force (e, new_bb);
2667 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2670 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2674 /* Implementation of CFG manipulation for linearized RTL. */
2675 struct cfg_hooks rtl_cfg_hooks = {
2677 rtl_verify_flow_info,
2679 rtl_create_basic_block,
2680 rtl_redirect_edge_and_branch,
2681 rtl_redirect_edge_and_branch_force,
2684 rtl_move_block_after,
2685 rtl_can_merge_blocks, /* can_merge_blocks_p */
2688 rtl_make_forwarder_block,
2689 rtl_tidy_fallthru_edge
2692 /* Implementation of CFG manipulation for cfg layout RTL, where
2693 basic block connected via fallthru edges does not have to be adjacent.
2694 This representation will hopefully become the default one in future
2695 version of the compiler. */
2696 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
2698 rtl_verify_flow_info_1,
2700 cfg_layout_create_basic_block,
2701 cfg_layout_redirect_edge_and_branch,
2702 cfg_layout_redirect_edge_and_branch_force,
2703 cfg_layout_delete_block,
2704 cfg_layout_split_block,
2705 rtl_move_block_after,
2706 cfg_layout_can_merge_blocks_p,
2707 cfg_layout_merge_blocks,
2708 cfg_layout_split_edge,
2709 rtl_make_forwarder_block,