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, 2005 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, 51 Franklin Street, Fifth Floor, 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"
62 #include "tree-pass.h"
64 static int can_delete_note_p (rtx);
65 static int can_delete_label_p (rtx);
66 static void commit_one_edge_insertion (edge, int);
67 static rtx last_loop_beg_note (rtx);
68 static bool back_edge_of_syntactic_loop_p (basic_block, basic_block);
69 static basic_block rtl_split_edge (edge);
70 static bool rtl_move_block_after (basic_block, basic_block);
71 static int rtl_verify_flow_info (void);
72 static basic_block cfg_layout_split_block (basic_block, void *);
73 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
74 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
75 static void cfg_layout_delete_block (basic_block);
76 static void rtl_delete_block (basic_block);
77 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
78 static edge rtl_redirect_edge_and_branch (edge, basic_block);
79 static basic_block rtl_split_block (basic_block, void *);
80 static void rtl_dump_bb (basic_block, FILE *, int);
81 static int rtl_verify_flow_info_1 (void);
82 static void mark_killed_regs (rtx, rtx, void *);
83 static void rtl_make_forwarder_block (edge);
85 /* Return true if NOTE is not one of the ones that must be kept paired,
86 so that we may simply delete it. */
89 can_delete_note_p (rtx note)
91 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
92 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
95 /* True if a given label can be deleted. */
98 can_delete_label_p (rtx label)
100 return (!LABEL_PRESERVE_P (label)
101 /* User declared labels must be preserved. */
102 && LABEL_NAME (label) == 0
103 && !in_expr_list_p (forced_labels, label));
106 /* Delete INSN by patching it out. Return the next insn. */
109 delete_insn (rtx insn)
111 rtx next = NEXT_INSN (insn);
113 bool really_delete = true;
117 /* Some labels can't be directly removed from the INSN chain, as they
118 might be references via variables, constant pool etc.
119 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
120 if (! can_delete_label_p (insn))
122 const char *name = LABEL_NAME (insn);
124 really_delete = false;
125 PUT_CODE (insn, NOTE);
126 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
127 NOTE_DELETED_LABEL_NAME (insn) = name;
130 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
135 /* If this insn has already been deleted, something is very wrong. */
136 gcc_assert (!INSN_DELETED_P (insn));
138 INSN_DELETED_P (insn) = 1;
141 /* If deleting a jump, decrement the use count of the label. Deleting
142 the label itself should happen in the normal course of block merging. */
145 && LABEL_P (JUMP_LABEL (insn)))
146 LABEL_NUSES (JUMP_LABEL (insn))--;
148 /* Also if deleting an insn that references a label. */
151 while ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
152 && LABEL_P (XEXP (note, 0)))
154 LABEL_NUSES (XEXP (note, 0))--;
155 remove_note (insn, note);
160 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
161 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
163 rtx pat = PATTERN (insn);
164 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
165 int len = XVECLEN (pat, diff_vec_p);
168 for (i = 0; i < len; i++)
170 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
172 /* When deleting code in bulk (e.g. removing many unreachable
173 blocks) we can delete a label that's a target of the vector
174 before deleting the vector itself. */
176 LABEL_NUSES (label)--;
183 /* Like delete_insn but also purge dead edges from BB. */
185 delete_insn_and_edges (rtx insn)
191 && BLOCK_FOR_INSN (insn)
192 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
194 x = delete_insn (insn);
196 purge_dead_edges (BLOCK_FOR_INSN (insn));
200 /* Unlink a chain of insns between START and FINISH, leaving notes
201 that must be paired. */
204 delete_insn_chain (rtx start, rtx finish)
208 /* Unchain the insns one by one. It would be quicker to delete all of these
209 with a single unchaining, rather than one at a time, but we need to keep
213 next = NEXT_INSN (start);
214 if (NOTE_P (start) && !can_delete_note_p (start))
217 next = delete_insn (start);
225 /* Like delete_insn but also purge dead edges from BB. */
227 delete_insn_chain_and_edges (rtx first, rtx last)
232 && BLOCK_FOR_INSN (last)
233 && BB_END (BLOCK_FOR_INSN (last)) == last)
235 delete_insn_chain (first, last);
237 purge_dead_edges (BLOCK_FOR_INSN (last));
240 /* Create a new basic block consisting of the instructions between HEAD and END
241 inclusive. This function is designed to allow fast BB construction - reuses
242 the note and basic block struct in BB_NOTE, if any and do not grow
243 BASIC_BLOCK chain and should be used directly only by CFG construction code.
244 END can be NULL in to create new empty basic block before HEAD. Both END
245 and HEAD can be NULL to create basic block at the end of INSN chain.
246 AFTER is the basic block we should be put after. */
249 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
254 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
257 /* If we found an existing note, thread it back onto the chain. */
265 after = PREV_INSN (head);
269 if (after != bb_note && NEXT_INSN (after) != bb_note)
270 reorder_insns_nobb (bb_note, bb_note, after);
274 /* Otherwise we must create a note and a basic block structure. */
278 init_rtl_bb_info (bb);
281 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
282 else if (LABEL_P (head) && end)
284 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
290 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
296 NOTE_BASIC_BLOCK (bb_note) = bb;
299 /* Always include the bb note in the block. */
300 if (NEXT_INSN (end) == bb_note)
305 bb->index = last_basic_block++;
306 bb->flags = BB_NEW | BB_RTL;
307 link_block (bb, after);
308 SET_BASIC_BLOCK (bb->index, bb);
309 update_bb_for_insn (bb);
310 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
312 /* Tag the block so that we know it has been used when considering
313 other basic block notes. */
319 /* Create new basic block consisting of instructions in between HEAD and END
320 and place it to the BB chain after block AFTER. END can be NULL in to
321 create new empty basic block before HEAD. Both END and HEAD can be NULL to
322 create basic block at the end of INSN chain. */
325 rtl_create_basic_block (void *headp, void *endp, basic_block after)
327 rtx head = headp, end = endp;
330 /* Grow the basic block array if needed. */
331 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
333 size_t old_size = VEC_length (basic_block, basic_block_info);
334 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
336 VEC_safe_grow (basic_block, gc, basic_block_info, new_size);
337 p = VEC_address (basic_block, basic_block_info);
338 memset (&p[old_size], 0, sizeof (basic_block) * (new_size - old_size));
343 bb = create_basic_block_structure (head, end, NULL, after);
349 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
351 basic_block newbb = rtl_create_basic_block (head, end, after);
356 /* Delete the insns in a (non-live) block. We physically delete every
357 non-deleted-note insn, and update the flow graph appropriately.
359 Return nonzero if we deleted an exception handler. */
361 /* ??? Preserving all such notes strikes me as wrong. It would be nice
362 to post-process the stream to remove empty blocks, loops, ranges, etc. */
365 rtl_delete_block (basic_block b)
369 /* If the head of this block is a CODE_LABEL, then it might be the
370 label for an exception handler which can't be reached. We need
371 to remove the label from the exception_handler_label list. */
374 maybe_remove_eh_handler (insn);
376 /* Include any jump table following the basic block. */
378 if (tablejump_p (end, NULL, &tmp))
381 /* Include any barriers that may follow the basic block. */
382 tmp = next_nonnote_insn (end);
383 while (tmp && BARRIER_P (tmp))
386 tmp = next_nonnote_insn (end);
389 /* Selectively delete the entire chain. */
391 delete_insn_chain (insn, end);
394 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
397 compute_bb_for_insn (void)
403 rtx end = BB_END (bb);
406 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
408 BLOCK_FOR_INSN (insn) = bb;
415 /* Release the basic_block_for_insn array. */
418 free_bb_for_insn (void)
421 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
422 if (!BARRIER_P (insn))
423 BLOCK_FOR_INSN (insn) = NULL;
427 struct tree_opt_pass pass_free_cfg =
431 free_bb_for_insn, /* execute */
434 0, /* static_pass_number */
436 0, /* properties_required */
437 0, /* properties_provided */
438 PROP_cfg, /* properties_destroyed */
439 0, /* todo_flags_start */
440 0, /* todo_flags_finish */
444 /* Return RTX to emit after when we want to emit code on the entry of function. */
446 entry_of_function (void)
448 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
449 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
452 /* Update insns block within BB. */
455 update_bb_for_insn (basic_block bb)
459 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
461 if (!BARRIER_P (insn))
462 set_block_for_insn (insn, bb);
463 if (insn == BB_END (bb))
468 /* Creates a new basic block just after basic block B by splitting
469 everything after specified instruction I. */
472 rtl_split_block (basic_block bb, void *insnp)
481 insn = first_insn_after_basic_block_note (bb);
484 insn = PREV_INSN (insn);
486 insn = get_last_insn ();
489 /* We probably should check type of the insn so that we do not create
490 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
492 if (insn == BB_END (bb))
493 emit_note_after (NOTE_INSN_DELETED, insn);
495 /* Create the new basic block. */
496 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
497 BB_COPY_PARTITION (new_bb, bb);
500 /* Redirect the outgoing edges. */
501 new_bb->succs = bb->succs;
503 FOR_EACH_EDGE (e, ei, new_bb->succs)
506 if (bb->il.rtl->global_live_at_start)
508 new_bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
509 new_bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
510 COPY_REG_SET (new_bb->il.rtl->global_live_at_end, bb->il.rtl->global_live_at_end);
512 /* We now have to calculate which registers are live at the end
513 of the split basic block and at the start of the new basic
514 block. Start with those registers that are known to be live
515 at the end of the original basic block and get
516 propagate_block to determine which registers are live. */
517 COPY_REG_SET (new_bb->il.rtl->global_live_at_start, bb->il.rtl->global_live_at_end);
518 propagate_block (new_bb, new_bb->il.rtl->global_live_at_start, NULL, NULL, 0);
519 COPY_REG_SET (bb->il.rtl->global_live_at_end,
520 new_bb->il.rtl->global_live_at_start);
521 #ifdef HAVE_conditional_execution
522 /* In the presence of conditional execution we are not able to update
523 liveness precisely. */
524 if (reload_completed)
526 bb->flags |= BB_DIRTY;
527 new_bb->flags |= BB_DIRTY;
535 /* Blocks A and B are to be merged into a single block A. The insns
536 are already contiguous. */
539 rtl_merge_blocks (basic_block a, basic_block b)
541 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
542 rtx del_first = NULL_RTX, del_last = NULL_RTX;
545 /* If there was a CODE_LABEL beginning B, delete it. */
546 if (LABEL_P (b_head))
548 /* This might have been an EH label that no longer has incoming
549 EH edges. Update data structures to match. */
550 maybe_remove_eh_handler (b_head);
552 /* Detect basic blocks with nothing but a label. This can happen
553 in particular at the end of a function. */
557 del_first = del_last = b_head;
558 b_head = NEXT_INSN (b_head);
561 /* Delete the basic block note and handle blocks containing just that
563 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
571 b_head = NEXT_INSN (b_head);
574 /* If there was a jump out of A, delete it. */
579 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
581 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
582 || prev == BB_HEAD (a))
588 /* If this was a conditional jump, we need to also delete
589 the insn that set cc0. */
590 if (only_sets_cc0_p (prev))
594 prev = prev_nonnote_insn (prev);
601 a_end = PREV_INSN (del_first);
603 else if (BARRIER_P (NEXT_INSN (a_end)))
604 del_first = NEXT_INSN (a_end);
606 /* Delete everything marked above as well as crap that might be
607 hanging out between the two blocks. */
609 delete_insn_chain (del_first, del_last);
611 /* Reassociate the insns of B with A. */
616 for (x = a_end; x != b_end; x = NEXT_INSN (x))
617 set_block_for_insn (x, a);
619 set_block_for_insn (b_end, a);
625 a->il.rtl->global_live_at_end = b->il.rtl->global_live_at_end;
628 /* Return true when block A and B can be merged. */
630 rtl_can_merge_blocks (basic_block a,basic_block b)
632 /* If we are partitioning hot/cold basic blocks, we don't want to
633 mess up unconditional or indirect jumps that cross between hot
636 Basic block partitioning may result in some jumps that appear to
637 be optimizable (or blocks that appear to be mergeable), but which really
638 must be left untouched (they are required to make it safely across
639 partition boundaries). See the comments at the top of
640 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
642 if (BB_PARTITION (a) != BB_PARTITION (b))
645 /* There must be exactly one edge in between the blocks. */
646 return (single_succ_p (a)
647 && single_succ (a) == b
650 /* Must be simple edge. */
651 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
653 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
654 /* If the jump insn has side effects,
655 we can't kill the edge. */
656 && (!JUMP_P (BB_END (a))
658 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
661 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
665 block_label (basic_block block)
667 if (block == EXIT_BLOCK_PTR)
670 if (!LABEL_P (BB_HEAD (block)))
672 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
675 return BB_HEAD (block);
678 /* Attempt to perform edge redirection by replacing possibly complex jump
679 instruction by unconditional jump or removing jump completely. This can
680 apply only if all edges now point to the same block. The parameters and
681 return values are equivalent to redirect_edge_and_branch. */
684 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
686 basic_block src = e->src;
687 rtx insn = BB_END (src), kill_from;
691 /* If we are partitioning hot/cold basic blocks, we don't want to
692 mess up unconditional or indirect jumps that cross between hot
695 Basic block partitioning may result in some jumps that appear to
696 be optimizable (or blocks that appear to be mergeable), but which really
697 must be left untouched (they are required to make it safely across
698 partition boundaries). See the comments at the top of
699 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
701 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
702 || BB_PARTITION (src) != BB_PARTITION (target))
705 /* We can replace or remove a complex jump only when we have exactly
706 two edges. Also, if we have exactly one outgoing edge, we can
708 if (EDGE_COUNT (src->succs) >= 3
709 /* Verify that all targets will be TARGET. Specifically, the
710 edge that is not E must also go to TARGET. */
711 || (EDGE_COUNT (src->succs) == 2
712 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
715 if (!onlyjump_p (insn))
717 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
720 /* Avoid removing branch with side effects. */
721 set = single_set (insn);
722 if (!set || side_effects_p (set))
725 /* In case we zap a conditional jump, we'll need to kill
726 the cc0 setter too. */
729 if (reg_mentioned_p (cc0_rtx, PATTERN (insn)))
730 kill_from = PREV_INSN (insn);
733 /* See if we can create the fallthru edge. */
734 if (in_cfglayout || can_fallthru (src, target))
737 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
740 /* Selectively unlink whole insn chain. */
743 rtx insn = src->il.rtl->footer;
745 delete_insn_chain (kill_from, BB_END (src));
747 /* Remove barriers but keep jumptables. */
750 if (BARRIER_P (insn))
752 if (PREV_INSN (insn))
753 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
755 src->il.rtl->footer = NEXT_INSN (insn);
756 if (NEXT_INSN (insn))
757 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
761 insn = NEXT_INSN (insn);
765 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)));
768 /* If this already is simplejump, redirect it. */
769 else if (simplejump_p (insn))
771 if (e->dest == target)
774 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
775 INSN_UID (insn), e->dest->index, target->index);
776 if (!redirect_jump (insn, block_label (target), 0))
778 gcc_assert (target == EXIT_BLOCK_PTR);
783 /* Cannot do anything for target exit block. */
784 else if (target == EXIT_BLOCK_PTR)
787 /* Or replace possibly complicated jump insn by simple jump insn. */
790 rtx target_label = block_label (target);
791 rtx barrier, label, table;
793 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
794 JUMP_LABEL (BB_END (src)) = target_label;
795 LABEL_NUSES (target_label)++;
797 fprintf (dump_file, "Replacing insn %i by jump %i\n",
798 INSN_UID (insn), INSN_UID (BB_END (src)));
801 delete_insn_chain (kill_from, insn);
803 /* Recognize a tablejump that we are converting to a
804 simple jump and remove its associated CODE_LABEL
805 and ADDR_VEC or ADDR_DIFF_VEC. */
806 if (tablejump_p (insn, &label, &table))
807 delete_insn_chain (label, table);
809 barrier = next_nonnote_insn (BB_END (src));
810 if (!barrier || !BARRIER_P (barrier))
811 emit_barrier_after (BB_END (src));
814 if (barrier != NEXT_INSN (BB_END (src)))
816 /* Move the jump before barrier so that the notes
817 which originally were or were created before jump table are
818 inside the basic block. */
819 rtx new_insn = BB_END (src);
822 for (tmp = NEXT_INSN (BB_END (src)); tmp != barrier;
823 tmp = NEXT_INSN (tmp))
824 set_block_for_insn (tmp, src);
826 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
827 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
829 NEXT_INSN (new_insn) = barrier;
830 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
832 PREV_INSN (new_insn) = PREV_INSN (barrier);
833 PREV_INSN (barrier) = new_insn;
838 /* Keep only one edge out and set proper flags. */
839 if (!single_succ_p (src))
841 gcc_assert (single_succ_p (src));
843 e = single_succ_edge (src);
845 e->flags = EDGE_FALLTHRU;
849 e->probability = REG_BR_PROB_BASE;
850 e->count = src->count;
852 /* We don't want a block to end on a line-number note since that has
853 the potential of changing the code between -g and not -g. */
854 while (NOTE_P (BB_END (e->src))
855 && NOTE_LINE_NUMBER (BB_END (e->src)) >= 0)
856 delete_insn (BB_END (e->src));
858 if (e->dest != target)
859 redirect_edge_succ (e, target);
864 /* Return last loop_beg note appearing after INSN, before start of next
865 basic block. Return INSN if there are no such notes.
867 When emitting jump to redirect a fallthru edge, it should always appear
868 after the LOOP_BEG notes, as loop optimizer expect loop to either start by
869 fallthru edge or jump following the LOOP_BEG note jumping to the loop exit
873 last_loop_beg_note (rtx insn)
877 for (insn = NEXT_INSN (insn); insn && NOTE_P (insn)
878 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK;
879 insn = NEXT_INSN (insn))
880 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
886 /* Redirect edge representing branch of (un)conditional jump or tablejump,
889 redirect_branch_edge (edge e, basic_block target)
892 rtx old_label = BB_HEAD (e->dest);
893 basic_block src = e->src;
894 rtx insn = BB_END (src);
896 /* We can only redirect non-fallthru edges of jump insn. */
897 if (e->flags & EDGE_FALLTHRU)
899 else if (!JUMP_P (insn))
902 /* Recognize a tablejump and adjust all matching cases. */
903 if (tablejump_p (insn, NULL, &tmp))
907 rtx new_label = block_label (target);
909 if (target == EXIT_BLOCK_PTR)
911 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
912 vec = XVEC (PATTERN (tmp), 0);
914 vec = XVEC (PATTERN (tmp), 1);
916 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
917 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
919 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
920 --LABEL_NUSES (old_label);
921 ++LABEL_NUSES (new_label);
924 /* Handle casesi dispatch insns. */
925 if ((tmp = single_set (insn)) != NULL
926 && SET_DEST (tmp) == pc_rtx
927 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
928 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
929 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
931 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
933 --LABEL_NUSES (old_label);
934 ++LABEL_NUSES (new_label);
939 /* ?? We may play the games with moving the named labels from
940 one basic block to the other in case only one computed_jump is
942 if (computed_jump_p (insn)
943 /* A return instruction can't be redirected. */
944 || returnjump_p (insn))
947 /* If the insn doesn't go where we think, we're confused. */
948 gcc_assert (JUMP_LABEL (insn) == old_label);
950 /* If the substitution doesn't succeed, die. This can happen
951 if the back end emitted unrecognizable instructions or if
952 target is exit block on some arches. */
953 if (!redirect_jump (insn, block_label (target), 0))
955 gcc_assert (target == EXIT_BLOCK_PTR);
961 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
962 e->src->index, e->dest->index, target->index);
964 if (e->dest != target)
965 e = redirect_edge_succ_nodup (e, target);
969 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
970 expense of adding new instructions or reordering basic blocks.
972 Function can be also called with edge destination equivalent to the TARGET.
973 Then it should try the simplifications and do nothing if none is possible.
975 Return edge representing the branch if transformation succeeded. Return NULL
977 We still return NULL in case E already destinated TARGET and we didn't
978 managed to simplify instruction stream. */
981 rtl_redirect_edge_and_branch (edge e, basic_block target)
984 basic_block src = e->src;
986 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
989 if (e->dest == target)
992 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
994 src->flags |= BB_DIRTY;
998 ret = redirect_branch_edge (e, target);
1002 src->flags |= BB_DIRTY;
1006 /* Like force_nonfallthru below, but additionally performs redirection
1007 Used by redirect_edge_and_branch_force. */
1010 force_nonfallthru_and_redirect (edge e, basic_block target)
1012 basic_block jump_block, new_bb = NULL, src = e->src;
1015 int abnormal_edge_flags = 0;
1017 /* In the case the last instruction is conditional jump to the next
1018 instruction, first redirect the jump itself and then continue
1019 by creating a basic block afterwards to redirect fallthru edge. */
1020 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1021 && any_condjump_p (BB_END (e->src))
1022 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1025 edge b = unchecked_make_edge (e->src, target, 0);
1028 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1029 gcc_assert (redirected);
1031 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1034 int prob = INTVAL (XEXP (note, 0));
1036 b->probability = prob;
1037 b->count = e->count * prob / REG_BR_PROB_BASE;
1038 e->probability -= e->probability;
1039 e->count -= b->count;
1040 if (e->probability < 0)
1047 if (e->flags & EDGE_ABNORMAL)
1049 /* Irritating special case - fallthru edge to the same block as abnormal
1051 We can't redirect abnormal edge, but we still can split the fallthru
1052 one and create separate abnormal edge to original destination.
1053 This allows bb-reorder to make such edge non-fallthru. */
1054 gcc_assert (e->dest == target);
1055 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1056 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1060 gcc_assert (e->flags & EDGE_FALLTHRU);
1061 if (e->src == ENTRY_BLOCK_PTR)
1063 /* We can't redirect the entry block. Create an empty block
1064 at the start of the function which we use to add the new
1070 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1072 /* Change the existing edge's source to be the new block, and add
1073 a new edge from the entry block to the new block. */
1075 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1079 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1089 VEC_safe_push (edge, gc, bb->succs, e);
1090 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1094 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1096 /* Create the new structures. */
1098 /* If the old block ended with a tablejump, skip its table
1099 by searching forward from there. Otherwise start searching
1100 forward from the last instruction of the old block. */
1101 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1102 note = BB_END (e->src);
1104 /* Position the new block correctly relative to loop notes. */
1105 note = last_loop_beg_note (note);
1106 note = NEXT_INSN (note);
1108 jump_block = create_basic_block (note, NULL, e->src);
1109 jump_block->count = e->count;
1110 jump_block->frequency = EDGE_FREQUENCY (e);
1111 jump_block->loop_depth = target->loop_depth;
1113 if (target->il.rtl->global_live_at_start)
1115 jump_block->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
1116 jump_block->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
1117 COPY_REG_SET (jump_block->il.rtl->global_live_at_start,
1118 target->il.rtl->global_live_at_start);
1119 COPY_REG_SET (jump_block->il.rtl->global_live_at_end,
1120 target->il.rtl->global_live_at_start);
1123 /* Make sure new block ends up in correct hot/cold section. */
1125 BB_COPY_PARTITION (jump_block, e->src);
1126 if (flag_reorder_blocks_and_partition
1127 && targetm.have_named_sections
1128 && JUMP_P (BB_END (jump_block))
1129 && !any_condjump_p (BB_END (jump_block))
1130 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1131 REG_NOTES (BB_END (jump_block)) = gen_rtx_EXPR_LIST (REG_CROSSING_JUMP,
1138 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1139 new_edge->probability = e->probability;
1140 new_edge->count = e->count;
1142 /* Redirect old edge. */
1143 redirect_edge_pred (e, jump_block);
1144 e->probability = REG_BR_PROB_BASE;
1146 new_bb = jump_block;
1149 jump_block = e->src;
1151 e->flags &= ~EDGE_FALLTHRU;
1152 if (target == EXIT_BLOCK_PTR)
1155 emit_jump_insn_after_noloc (gen_return (), BB_END (jump_block));
1162 rtx label = block_label (target);
1163 emit_jump_insn_after_noloc (gen_jump (label), BB_END (jump_block));
1164 JUMP_LABEL (BB_END (jump_block)) = label;
1165 LABEL_NUSES (label)++;
1168 emit_barrier_after (BB_END (jump_block));
1169 redirect_edge_succ_nodup (e, target);
1171 if (abnormal_edge_flags)
1172 make_edge (src, target, abnormal_edge_flags);
1177 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1178 (and possibly create new basic block) to make edge non-fallthru.
1179 Return newly created BB or NULL if none. */
1182 force_nonfallthru (edge e)
1184 return force_nonfallthru_and_redirect (e, e->dest);
1187 /* Redirect edge even at the expense of creating new jump insn or
1188 basic block. Return new basic block if created, NULL otherwise.
1189 Conversion must be possible. */
1192 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1194 if (redirect_edge_and_branch (e, target)
1195 || e->dest == target)
1198 /* In case the edge redirection failed, try to force it to be non-fallthru
1199 and redirect newly created simplejump. */
1200 return force_nonfallthru_and_redirect (e, target);
1203 /* The given edge should potentially be a fallthru edge. If that is in
1204 fact true, delete the jump and barriers that are in the way. */
1207 rtl_tidy_fallthru_edge (edge e)
1210 basic_block b = e->src, c = b->next_bb;
1212 /* ??? In a late-running flow pass, other folks may have deleted basic
1213 blocks by nopping out blocks, leaving multiple BARRIERs between here
1214 and the target label. They ought to be chastised and fixed.
1216 We can also wind up with a sequence of undeletable labels between
1217 one block and the next.
1219 So search through a sequence of barriers, labels, and notes for
1220 the head of block C and assert that we really do fall through. */
1222 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1226 /* Remove what will soon cease being the jump insn from the source block.
1227 If block B consisted only of this single jump, turn it into a deleted
1232 && (any_uncondjump_p (q)
1233 || single_succ_p (b)))
1236 /* If this was a conditional jump, we need to also delete
1237 the insn that set cc0. */
1238 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1244 /* We don't want a block to end on a line-number note since that has
1245 the potential of changing the code between -g and not -g. */
1246 while (NOTE_P (q) && NOTE_LINE_NUMBER (q) >= 0)
1250 /* Selectively unlink the sequence. */
1251 if (q != PREV_INSN (BB_HEAD (c)))
1252 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)));
1254 e->flags |= EDGE_FALLTHRU;
1257 /* Helper function for split_edge. Return true in case edge BB2 to BB1
1258 is back edge of syntactic loop. */
1261 back_edge_of_syntactic_loop_p (basic_block bb1, basic_block bb2)
1270 /* ??? Could we guarantee that bb indices are monotone, so that we could
1271 just compare them? */
1272 for (bb = bb1; bb && bb != bb2; bb = bb->next_bb)
1278 for (insn = BB_END (bb1); insn != BB_HEAD (bb2) && count >= 0;
1279 insn = NEXT_INSN (insn))
1282 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1284 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1291 /* Should move basic block BB after basic block AFTER. NIY. */
1294 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1295 basic_block after ATTRIBUTE_UNUSED)
1300 /* Split a (typically critical) edge. Return the new block.
1301 The edge must not be abnormal.
1303 ??? The code generally expects to be called on critical edges.
1304 The case of a block ending in an unconditional jump to a
1305 block with multiple predecessors is not handled optimally. */
1308 rtl_split_edge (edge edge_in)
1313 /* Abnormal edges cannot be split. */
1314 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1316 /* We are going to place the new block in front of edge destination.
1317 Avoid existence of fallthru predecessors. */
1318 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1323 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1324 if (e->flags & EDGE_FALLTHRU)
1328 force_nonfallthru (e);
1331 /* Create the basic block note.
1333 Where we place the note can have a noticeable impact on the generated
1334 code. Consider this cfg:
1344 If we need to insert an insn on the edge from block 0 to block 1,
1345 we want to ensure the instructions we insert are outside of any
1346 loop notes that physically sit between block 0 and block 1. Otherwise
1347 we confuse the loop optimizer into thinking the loop is a phony. */
1349 if (edge_in->dest != EXIT_BLOCK_PTR
1350 && PREV_INSN (BB_HEAD (edge_in->dest))
1351 && NOTE_P (PREV_INSN (BB_HEAD (edge_in->dest)))
1352 && (NOTE_LINE_NUMBER (PREV_INSN (BB_HEAD (edge_in->dest)))
1353 == NOTE_INSN_LOOP_BEG)
1354 && !back_edge_of_syntactic_loop_p (edge_in->dest, edge_in->src))
1355 before = PREV_INSN (BB_HEAD (edge_in->dest));
1356 else if (edge_in->dest != EXIT_BLOCK_PTR)
1357 before = BB_HEAD (edge_in->dest);
1361 /* If this is a fall through edge to the exit block, the blocks might be
1362 not adjacent, and the right place is the after the source. */
1363 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1365 before = NEXT_INSN (BB_END (edge_in->src));
1368 && NOTE_LINE_NUMBER (before) == NOTE_INSN_LOOP_END)
1369 before = NEXT_INSN (before);
1370 bb = create_basic_block (before, NULL, edge_in->src);
1371 BB_COPY_PARTITION (bb, edge_in->src);
1375 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1376 /* ??? Why not edge_in->dest->prev_bb here? */
1377 BB_COPY_PARTITION (bb, edge_in->dest);
1380 /* ??? This info is likely going to be out of date very soon. */
1381 if (edge_in->dest->il.rtl->global_live_at_start)
1383 bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
1384 bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
1385 COPY_REG_SET (bb->il.rtl->global_live_at_start,
1386 edge_in->dest->il.rtl->global_live_at_start);
1387 COPY_REG_SET (bb->il.rtl->global_live_at_end,
1388 edge_in->dest->il.rtl->global_live_at_start);
1391 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1393 /* For non-fallthru edges, we must adjust the predecessor's
1394 jump instruction to target our new block. */
1395 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1397 edge redirected = redirect_edge_and_branch (edge_in, bb);
1398 gcc_assert (redirected);
1401 redirect_edge_succ (edge_in, bb);
1406 /* Queue instructions for insertion on an edge between two basic blocks.
1407 The new instructions and basic blocks (if any) will not appear in the
1408 CFG until commit_edge_insertions is called. */
1411 insert_insn_on_edge (rtx pattern, edge e)
1413 /* We cannot insert instructions on an abnormal critical edge.
1414 It will be easier to find the culprit if we die now. */
1415 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1417 if (e->insns.r == NULL_RTX)
1420 push_to_sequence (e->insns.r);
1422 emit_insn (pattern);
1424 e->insns.r = get_insns ();
1428 /* Called from safe_insert_insn_on_edge through note_stores, marks live
1429 registers that are killed by the store. */
1431 mark_killed_regs (rtx reg, rtx set ATTRIBUTE_UNUSED, void *data)
1433 regset killed = data;
1436 if (GET_CODE (reg) == SUBREG)
1437 reg = SUBREG_REG (reg);
1440 regno = REGNO (reg);
1441 if (regno >= FIRST_PSEUDO_REGISTER)
1442 SET_REGNO_REG_SET (killed, regno);
1445 for (i = 0; i < (int) hard_regno_nregs[regno][GET_MODE (reg)]; i++)
1446 SET_REGNO_REG_SET (killed, regno + i);
1450 /* Similar to insert_insn_on_edge, tries to put INSN to edge E. Additionally
1451 it checks whether this will not clobber the registers that are live on the
1452 edge (i.e. it requires liveness information to be up-to-date) and if there
1453 are some, then it tries to save and restore them. Returns true if
1456 safe_insert_insn_on_edge (rtx insn, edge e)
1460 rtx save_regs = NULL_RTX;
1462 enum machine_mode mode;
1463 reg_set_iterator rsi;
1465 killed = ALLOC_REG_SET (®_obstack);
1467 for (x = insn; x; x = NEXT_INSN (x))
1469 note_stores (PATTERN (x), mark_killed_regs, killed);
1471 /* Mark all hard registers as killed. Register allocator/reload cannot
1472 cope with the situation when life range of hard register spans operation
1473 for that the appropriate register is needed, i.e. it would be unsafe to
1474 extend the life ranges of hard registers. */
1475 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1476 if (!fixed_regs[regno]
1477 && !REGNO_PTR_FRAME_P (regno))
1478 SET_REGNO_REG_SET (killed, regno);
1480 bitmap_and_into (killed, e->dest->il.rtl->global_live_at_start);
1482 EXECUTE_IF_SET_IN_REG_SET (killed, 0, regno, rsi)
1484 mode = regno < FIRST_PSEUDO_REGISTER
1485 ? reg_raw_mode[regno]
1486 : GET_MODE (regno_reg_rtx[regno]);
1487 if (mode == VOIDmode)
1490 /* Avoid copying in CCmode if we can't. */
1491 if (!can_copy_p (mode))
1494 save_regs = alloc_EXPR_LIST (0,
1497 gen_raw_REG (mode, regno)),
1506 for (x = save_regs; x; x = XEXP (x, 1))
1508 from = XEXP (XEXP (x, 0), 1);
1509 to = XEXP (XEXP (x, 0), 0);
1510 emit_move_insn (to, from);
1513 for (x = save_regs; x; x = XEXP (x, 1))
1515 from = XEXP (XEXP (x, 0), 0);
1516 to = XEXP (XEXP (x, 0), 1);
1517 emit_move_insn (to, from);
1519 insn = get_insns ();
1521 free_EXPR_LIST_list (&save_regs);
1523 insert_insn_on_edge (insn, e);
1525 FREE_REG_SET (killed);
1530 /* Update the CFG for the instructions queued on edge E. */
1533 commit_one_edge_insertion (edge e, int watch_calls)
1535 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1536 basic_block bb = NULL;
1538 /* Pull the insns off the edge now since the edge might go away. */
1540 e->insns.r = NULL_RTX;
1542 /* Special case -- avoid inserting code between call and storing
1543 its return value. */
1544 if (watch_calls && (e->flags & EDGE_FALLTHRU)
1545 && single_pred_p (e->dest)
1546 && e->src != ENTRY_BLOCK_PTR
1547 && CALL_P (BB_END (e->src)))
1549 rtx next = next_nonnote_insn (BB_END (e->src));
1551 after = BB_HEAD (e->dest);
1552 /* The first insn after the call may be a stack pop, skip it. */
1554 && keep_with_call_p (next))
1557 next = next_nonnote_insn (next);
1561 if (!before && !after)
1563 /* Figure out where to put these things. If the destination has
1564 one predecessor, insert there. Except for the exit block. */
1565 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1569 /* Get the location correct wrt a code label, and "nice" wrt
1570 a basic block note, and before everything else. */
1573 tmp = NEXT_INSN (tmp);
1574 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1575 tmp = NEXT_INSN (tmp);
1576 if (tmp == BB_HEAD (bb))
1579 after = PREV_INSN (tmp);
1581 after = get_last_insn ();
1584 /* If the source has one successor and the edge is not abnormal,
1585 insert there. Except for the entry block. */
1586 else if ((e->flags & EDGE_ABNORMAL) == 0
1587 && single_succ_p (e->src)
1588 && e->src != ENTRY_BLOCK_PTR)
1592 /* It is possible to have a non-simple jump here. Consider a target
1593 where some forms of unconditional jumps clobber a register. This
1594 happens on the fr30 for example.
1596 We know this block has a single successor, so we can just emit
1597 the queued insns before the jump. */
1598 if (JUMP_P (BB_END (bb)))
1599 for (before = BB_END (bb);
1600 NOTE_P (PREV_INSN (before))
1601 && NOTE_LINE_NUMBER (PREV_INSN (before)) ==
1602 NOTE_INSN_LOOP_BEG; before = PREV_INSN (before))
1606 /* We'd better be fallthru, or we've lost track of
1608 gcc_assert (e->flags & EDGE_FALLTHRU);
1610 after = BB_END (bb);
1613 /* Otherwise we must split the edge. */
1616 bb = split_edge (e);
1617 after = BB_END (bb);
1619 if (flag_reorder_blocks_and_partition
1620 && targetm.have_named_sections
1621 && e->src != ENTRY_BLOCK_PTR
1622 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1623 && !(e->flags & EDGE_CROSSING))
1625 rtx bb_note, cur_insn;
1628 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1629 cur_insn = NEXT_INSN (cur_insn))
1630 if (NOTE_P (cur_insn)
1631 && NOTE_LINE_NUMBER (cur_insn) == NOTE_INSN_BASIC_BLOCK)
1637 if (JUMP_P (BB_END (bb))
1638 && !any_condjump_p (BB_END (bb))
1639 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1640 REG_NOTES (BB_END (bb)) = gen_rtx_EXPR_LIST
1641 (REG_CROSSING_JUMP, NULL_RTX, REG_NOTES (BB_END (bb)));
1646 /* Now that we've found the spot, do the insertion. */
1650 emit_insn_before_noloc (insns, before);
1651 last = prev_nonnote_insn (before);
1654 last = emit_insn_after_noloc (insns, after);
1656 if (returnjump_p (last))
1658 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1659 This is not currently a problem because this only happens
1660 for the (single) epilogue, which already has a fallthru edge
1663 e = single_succ_edge (bb);
1664 gcc_assert (e->dest == EXIT_BLOCK_PTR
1665 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1667 e->flags &= ~EDGE_FALLTHRU;
1668 emit_barrier_after (last);
1671 delete_insn (before);
1674 gcc_assert (!JUMP_P (last));
1676 /* Mark the basic block for find_many_sub_basic_blocks. */
1680 /* Update the CFG for all queued instructions. */
1683 commit_edge_insertions (void)
1687 bool changed = false;
1689 #ifdef ENABLE_CHECKING
1690 verify_flow_info ();
1693 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1698 FOR_EACH_EDGE (e, ei, bb->succs)
1702 commit_one_edge_insertion (e, false);
1709 blocks = sbitmap_alloc (last_basic_block);
1710 sbitmap_zero (blocks);
1714 SET_BIT (blocks, bb->index);
1715 /* Check for forgotten bb->aux values before commit_edge_insertions
1717 gcc_assert (bb->aux == &bb->aux);
1720 find_many_sub_basic_blocks (blocks);
1721 sbitmap_free (blocks);
1724 /* Update the CFG for all queued instructions, taking special care of inserting
1725 code on edges between call and storing its return value. */
1728 commit_edge_insertions_watch_calls (void)
1732 bool changed = false;
1734 #ifdef ENABLE_CHECKING
1735 verify_flow_info ();
1738 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1743 FOR_EACH_EDGE (e, ei, bb->succs)
1747 commit_one_edge_insertion (e, true);
1754 blocks = sbitmap_alloc (last_basic_block);
1755 sbitmap_zero (blocks);
1759 SET_BIT (blocks, bb->index);
1760 /* Check for forgotten bb->aux values before commit_edge_insertions
1762 gcc_assert (bb->aux == &bb->aux);
1765 find_many_sub_basic_blocks (blocks);
1766 sbitmap_free (blocks);
1769 /* Print out RTL-specific basic block information (live information
1770 at start and end). */
1773 rtl_dump_bb (basic_block bb, FILE *outf, int indent)
1779 s_indent = alloca ((size_t) indent + 1);
1780 memset (s_indent, ' ', (size_t) indent);
1781 s_indent[indent] = '\0';
1783 fprintf (outf, ";;%s Registers live at start: ", s_indent);
1784 dump_regset (bb->il.rtl->global_live_at_start, outf);
1787 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1788 insn = NEXT_INSN (insn))
1789 print_rtl_single (outf, insn);
1791 fprintf (outf, ";;%s Registers live at end: ", s_indent);
1792 dump_regset (bb->il.rtl->global_live_at_end, outf);
1796 /* Like print_rtl, but also print out live information for the start of each
1800 print_rtl_with_bb (FILE *outf, rtx rtx_first)
1805 fprintf (outf, "(nil)\n");
1808 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1809 int max_uid = get_max_uid ();
1810 basic_block *start = XCNEWVEC (basic_block, max_uid);
1811 basic_block *end = XCNEWVEC (basic_block, max_uid);
1812 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1816 FOR_EACH_BB_REVERSE (bb)
1820 start[INSN_UID (BB_HEAD (bb))] = bb;
1821 end[INSN_UID (BB_END (bb))] = bb;
1822 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1824 enum bb_state state = IN_MULTIPLE_BB;
1826 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1828 in_bb_p[INSN_UID (x)] = state;
1830 if (x == BB_END (bb))
1835 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1839 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1841 fprintf (outf, ";; Start of basic block %d, registers live:",
1843 dump_regset (bb->il.rtl->global_live_at_start, outf);
1847 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1848 && !NOTE_P (tmp_rtx)
1849 && !BARRIER_P (tmp_rtx))
1850 fprintf (outf, ";; Insn is not within a basic block\n");
1851 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1852 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1854 did_output = print_rtl_single (outf, tmp_rtx);
1856 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1858 fprintf (outf, ";; End of basic block %d, registers live:\n",
1860 dump_regset (bb->il.rtl->global_live_at_end, outf);
1873 if (current_function_epilogue_delay_list != 0)
1875 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1876 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
1877 tmp_rtx = XEXP (tmp_rtx, 1))
1878 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1883 update_br_prob_note (basic_block bb)
1886 if (!JUMP_P (BB_END (bb)))
1888 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1889 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1891 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1894 /* Verify the CFG and RTL consistency common for both underlying RTL and
1897 Currently it does following checks:
1899 - test head/end pointers
1900 - overlapping of basic blocks
1901 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1902 - tails of basic blocks (ensure that boundary is necessary)
1903 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1904 and NOTE_INSN_BASIC_BLOCK
1905 - verify that no fall_thru edge crosses hot/cold partition boundaries
1907 In future it can be extended check a lot of other stuff as well
1908 (reachability of basic blocks, life information, etc. etc.). */
1911 rtl_verify_flow_info_1 (void)
1913 const int max_uid = get_max_uid ();
1914 rtx last_head = get_last_insn ();
1915 basic_block *bb_info;
1920 bb_info = XCNEWVEC (basic_block, max_uid);
1922 FOR_EACH_BB_REVERSE (bb)
1924 rtx head = BB_HEAD (bb);
1925 rtx end = BB_END (bb);
1927 /* Verify the end of the basic block is in the INSN chain. */
1928 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1932 if (!(bb->flags & BB_RTL))
1934 error ("BB_RTL flag not set for block %d", bb->index);
1940 error ("end insn %d for block %d not found in the insn stream",
1941 INSN_UID (end), bb->index);
1945 /* Work backwards from the end to the head of the basic block
1946 to verify the head is in the RTL chain. */
1947 for (; x != NULL_RTX; x = PREV_INSN (x))
1949 /* While walking over the insn chain, verify insns appear
1950 in only one basic block and initialize the BB_INFO array
1951 used by other passes. */
1952 if (bb_info[INSN_UID (x)] != NULL)
1954 error ("insn %d is in multiple basic blocks (%d and %d)",
1955 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
1959 bb_info[INSN_UID (x)] = bb;
1966 error ("head insn %d for block %d not found in the insn stream",
1967 INSN_UID (head), bb->index);
1974 /* Now check the basic blocks (boundaries etc.) */
1975 FOR_EACH_BB_REVERSE (bb)
1977 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1978 edge e, fallthru = NULL;
1982 if (JUMP_P (BB_END (bb))
1983 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1984 && EDGE_COUNT (bb->succs) >= 2
1985 && any_condjump_p (BB_END (bb)))
1987 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1988 && profile_status != PROFILE_ABSENT)
1990 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1991 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1995 FOR_EACH_EDGE (e, ei, bb->succs)
1997 if (e->flags & EDGE_FALLTHRU)
1999 n_fallthru++, fallthru = e;
2000 if ((e->flags & EDGE_CROSSING)
2001 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
2002 && e->src != ENTRY_BLOCK_PTR
2003 && e->dest != EXIT_BLOCK_PTR))
2005 error ("fallthru edge crosses section boundary (bb %i)",
2011 if ((e->flags & ~(EDGE_DFS_BACK
2013 | EDGE_IRREDUCIBLE_LOOP
2015 | EDGE_CROSSING)) == 0)
2018 if (e->flags & EDGE_ABNORMAL_CALL)
2021 if (e->flags & EDGE_EH)
2023 else if (e->flags & EDGE_ABNORMAL)
2027 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
2028 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
2030 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
2034 && (!JUMP_P (BB_END (bb))
2035 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
2036 || any_condjump_p (BB_END (bb))))))
2038 error ("too many outgoing branch edges from bb %i", bb->index);
2041 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
2043 error ("fallthru edge after unconditional jump %i", bb->index);
2046 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
2048 error ("wrong amount of branch edges after unconditional jump %i", bb->index);
2051 if (n_branch != 1 && any_condjump_p (BB_END (bb))
2052 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
2054 error ("wrong amount of branch edges after conditional jump %i",
2058 if (n_call && !CALL_P (BB_END (bb)))
2060 error ("call edges for non-call insn in bb %i", bb->index);
2064 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
2065 && (!JUMP_P (BB_END (bb))
2066 || any_condjump_p (BB_END (bb))
2067 || any_uncondjump_p (BB_END (bb))))
2069 error ("abnormal edges for no purpose in bb %i", bb->index);
2073 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
2074 /* We may have a barrier inside a basic block before dead code
2075 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2076 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
2079 if (! BLOCK_FOR_INSN (x))
2081 ("insn %d inside basic block %d but block_for_insn is NULL",
2082 INSN_UID (x), bb->index);
2085 ("insn %d inside basic block %d but block_for_insn is %i",
2086 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
2091 /* OK pointers are correct. Now check the header of basic
2092 block. It ought to contain optional CODE_LABEL followed
2093 by NOTE_BASIC_BLOCK. */
2097 if (BB_END (bb) == x)
2099 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2107 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
2109 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2114 if (BB_END (bb) == x)
2115 /* Do checks for empty blocks here. */
2118 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
2120 if (NOTE_INSN_BASIC_BLOCK_P (x))
2122 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2123 INSN_UID (x), bb->index);
2127 if (x == BB_END (bb))
2130 if (control_flow_insn_p (x))
2132 error ("in basic block %d:", bb->index);
2133 fatal_insn ("flow control insn inside a basic block", x);
2143 /* Verify the CFG and RTL consistency common for both underlying RTL and
2146 Currently it does following checks:
2147 - all checks of rtl_verify_flow_info_1
2148 - check that all insns are in the basic blocks
2149 (except the switch handling code, barriers and notes)
2150 - check that all returns are followed by barriers
2151 - check that all fallthru edge points to the adjacent blocks. */
2153 rtl_verify_flow_info (void)
2156 int err = rtl_verify_flow_info_1 ();
2159 const rtx rtx_first = get_insns ();
2160 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2162 FOR_EACH_BB_REVERSE (bb)
2167 if (bb->predictions)
2169 error ("bb prediction set for block %i, but it is not used in RTL land", bb->index);
2173 FOR_EACH_EDGE (e, ei, bb->succs)
2174 if (e->flags & EDGE_FALLTHRU)
2180 /* Ensure existence of barrier in BB with no fallthru edges. */
2181 for (insn = BB_END (bb); !insn || !BARRIER_P (insn);
2182 insn = NEXT_INSN (insn))
2185 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK))
2187 error ("missing barrier after block %i", bb->index);
2192 else if (e->src != ENTRY_BLOCK_PTR
2193 && e->dest != EXIT_BLOCK_PTR)
2197 if (e->src->next_bb != e->dest)
2200 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2201 e->src->index, e->dest->index);
2205 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2206 insn = NEXT_INSN (insn))
2207 if (BARRIER_P (insn) || INSN_P (insn))
2209 error ("verify_flow_info: Incorrect fallthru %i->%i",
2210 e->src->index, e->dest->index);
2211 fatal_insn ("wrong insn in the fallthru edge", insn);
2218 last_bb_seen = ENTRY_BLOCK_PTR;
2220 for (x = rtx_first; x; x = NEXT_INSN (x))
2222 if (NOTE_INSN_BASIC_BLOCK_P (x))
2224 bb = NOTE_BASIC_BLOCK (x);
2227 if (bb != last_bb_seen->next_bb)
2228 internal_error ("basic blocks not laid down consecutively");
2230 curr_bb = last_bb_seen = bb;
2235 switch (GET_CODE (x))
2242 /* An addr_vec is placed outside any basic block. */
2244 && JUMP_P (NEXT_INSN (x))
2245 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2246 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2249 /* But in any case, non-deletable labels can appear anywhere. */
2253 fatal_insn ("insn outside basic block", x);
2258 && returnjump_p (x) && ! condjump_p (x)
2259 && ! (NEXT_INSN (x) && BARRIER_P (NEXT_INSN (x))))
2260 fatal_insn ("return not followed by barrier", x);
2261 if (curr_bb && x == BB_END (curr_bb))
2265 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2267 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2268 num_bb_notes, n_basic_blocks);
2273 /* Assume that the preceding pass has possibly eliminated jump instructions
2274 or converted the unconditional jumps. Eliminate the edges from CFG.
2275 Return true if any edges are eliminated. */
2278 purge_dead_edges (basic_block bb)
2281 rtx insn = BB_END (bb), note;
2282 bool purged = false;
2286 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2287 if (NONJUMP_INSN_P (insn)
2288 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2292 if (! may_trap_p (PATTERN (insn))
2293 || ((eqnote = find_reg_equal_equiv_note (insn))
2294 && ! may_trap_p (XEXP (eqnote, 0))))
2295 remove_note (insn, note);
2298 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2299 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2301 /* There are three types of edges we need to handle correctly here: EH
2302 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2303 latter can appear when nonlocal gotos are used. */
2304 if (e->flags & EDGE_EH)
2306 if (can_throw_internal (BB_END (bb))
2307 /* If this is a call edge, verify that this is a call insn. */
2308 && (! (e->flags & EDGE_ABNORMAL_CALL)
2309 || CALL_P (BB_END (bb))))
2315 else if (e->flags & EDGE_ABNORMAL_CALL)
2317 if (CALL_P (BB_END (bb))
2318 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2319 || INTVAL (XEXP (note, 0)) >= 0))
2332 bb->flags |= BB_DIRTY;
2342 /* We do care only about conditional jumps and simplejumps. */
2343 if (!any_condjump_p (insn)
2344 && !returnjump_p (insn)
2345 && !simplejump_p (insn))
2348 /* Branch probability/prediction notes are defined only for
2349 condjumps. We've possibly turned condjump into simplejump. */
2350 if (simplejump_p (insn))
2352 note = find_reg_note (insn, REG_BR_PROB, NULL);
2354 remove_note (insn, note);
2355 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2356 remove_note (insn, note);
2359 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2361 /* Avoid abnormal flags to leak from computed jumps turned
2362 into simplejumps. */
2364 e->flags &= ~EDGE_ABNORMAL;
2366 /* See if this edge is one we should keep. */
2367 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2368 /* A conditional jump can fall through into the next
2369 block, so we should keep the edge. */
2374 else if (e->dest != EXIT_BLOCK_PTR
2375 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2376 /* If the destination block is the target of the jump,
2382 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2383 /* If the destination block is the exit block, and this
2384 instruction is a return, then keep the edge. */
2389 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2390 /* Keep the edges that correspond to exceptions thrown by
2391 this instruction and rematerialize the EDGE_ABNORMAL
2392 flag we just cleared above. */
2394 e->flags |= EDGE_ABNORMAL;
2399 /* We do not need this edge. */
2400 bb->flags |= BB_DIRTY;
2405 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2409 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2414 /* Redistribute probabilities. */
2415 if (single_succ_p (bb))
2417 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2418 single_succ_edge (bb)->count = bb->count;
2422 note = find_reg_note (insn, REG_BR_PROB, NULL);
2426 b = BRANCH_EDGE (bb);
2427 f = FALLTHRU_EDGE (bb);
2428 b->probability = INTVAL (XEXP (note, 0));
2429 f->probability = REG_BR_PROB_BASE - b->probability;
2430 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2431 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2436 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2438 /* First, there should not be any EH or ABCALL edges resulting
2439 from non-local gotos and the like. If there were, we shouldn't
2440 have created the sibcall in the first place. Second, there
2441 should of course never have been a fallthru edge. */
2442 gcc_assert (single_succ_p (bb));
2443 gcc_assert (single_succ_edge (bb)->flags
2444 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2449 /* If we don't see a jump insn, we don't know exactly why the block would
2450 have been broken at this point. Look for a simple, non-fallthru edge,
2451 as these are only created by conditional branches. If we find such an
2452 edge we know that there used to be a jump here and can then safely
2453 remove all non-fallthru edges. */
2455 FOR_EACH_EDGE (e, ei, bb->succs)
2456 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2465 /* Remove all but the fake and fallthru edges. The fake edge may be
2466 the only successor for this block in the case of noreturn
2468 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2470 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2472 bb->flags |= BB_DIRTY;
2480 gcc_assert (single_succ_p (bb));
2482 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2483 single_succ_edge (bb)->count = bb->count;
2486 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2491 /* Search all basic blocks for potentially dead edges and purge them. Return
2492 true if some edge has been eliminated. */
2495 purge_all_dead_edges (void)
2502 bool purged_here = purge_dead_edges (bb);
2504 purged |= purged_here;
2510 /* Same as split_block but update cfg_layout structures. */
2513 cfg_layout_split_block (basic_block bb, void *insnp)
2516 basic_block new_bb = rtl_split_block (bb, insn);
2518 new_bb->il.rtl->footer = bb->il.rtl->footer;
2519 bb->il.rtl->footer = NULL;
2525 /* Redirect Edge to DEST. */
2527 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2529 basic_block src = e->src;
2532 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2535 if (e->dest == dest)
2538 if (e->src != ENTRY_BLOCK_PTR
2539 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2541 src->flags |= BB_DIRTY;
2545 if (e->src == ENTRY_BLOCK_PTR
2546 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2549 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2550 e->src->index, dest->index);
2552 e->src->flags |= BB_DIRTY;
2553 redirect_edge_succ (e, dest);
2557 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2558 in the case the basic block appears to be in sequence. Avoid this
2561 if (e->flags & EDGE_FALLTHRU)
2563 /* Redirect any branch edges unified with the fallthru one. */
2564 if (JUMP_P (BB_END (src))
2565 && label_is_jump_target_p (BB_HEAD (e->dest),
2571 fprintf (dump_file, "Fallthru edge unified with branch "
2572 "%i->%i redirected to %i\n",
2573 e->src->index, e->dest->index, dest->index);
2574 e->flags &= ~EDGE_FALLTHRU;
2575 redirected = redirect_branch_edge (e, dest);
2576 gcc_assert (redirected);
2577 e->flags |= EDGE_FALLTHRU;
2578 e->src->flags |= BB_DIRTY;
2581 /* In case we are redirecting fallthru edge to the branch edge
2582 of conditional jump, remove it. */
2583 if (EDGE_COUNT (src->succs) == 2)
2585 /* Find the edge that is different from E. */
2586 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2589 && any_condjump_p (BB_END (src))
2590 && onlyjump_p (BB_END (src)))
2591 delete_insn (BB_END (src));
2593 ret = redirect_edge_succ_nodup (e, dest);
2595 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2596 e->src->index, e->dest->index, dest->index);
2599 ret = redirect_branch_edge (e, dest);
2601 /* We don't want simplejumps in the insn stream during cfglayout. */
2602 gcc_assert (!simplejump_p (BB_END (src)));
2604 src->flags |= BB_DIRTY;
2608 /* Simple wrapper as we always can redirect fallthru edges. */
2610 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2612 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2614 gcc_assert (redirected);
2618 /* Same as delete_basic_block but update cfg_layout structures. */
2621 cfg_layout_delete_block (basic_block bb)
2623 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2625 if (bb->il.rtl->header)
2627 next = BB_HEAD (bb);
2629 NEXT_INSN (prev) = bb->il.rtl->header;
2631 set_first_insn (bb->il.rtl->header);
2632 PREV_INSN (bb->il.rtl->header) = prev;
2633 insn = bb->il.rtl->header;
2634 while (NEXT_INSN (insn))
2635 insn = NEXT_INSN (insn);
2636 NEXT_INSN (insn) = next;
2637 PREV_INSN (next) = insn;
2639 next = NEXT_INSN (BB_END (bb));
2640 if (bb->il.rtl->footer)
2642 insn = bb->il.rtl->footer;
2645 if (BARRIER_P (insn))
2647 if (PREV_INSN (insn))
2648 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2650 bb->il.rtl->footer = NEXT_INSN (insn);
2651 if (NEXT_INSN (insn))
2652 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2656 insn = NEXT_INSN (insn);
2658 if (bb->il.rtl->footer)
2661 NEXT_INSN (insn) = bb->il.rtl->footer;
2662 PREV_INSN (bb->il.rtl->footer) = insn;
2663 while (NEXT_INSN (insn))
2664 insn = NEXT_INSN (insn);
2665 NEXT_INSN (insn) = next;
2667 PREV_INSN (next) = insn;
2669 set_last_insn (insn);
2672 if (bb->next_bb != EXIT_BLOCK_PTR)
2673 to = &bb->next_bb->il.rtl->header;
2675 to = &cfg_layout_function_footer;
2677 rtl_delete_block (bb);
2680 prev = NEXT_INSN (prev);
2682 prev = get_insns ();
2684 next = PREV_INSN (next);
2686 next = get_last_insn ();
2688 if (next && NEXT_INSN (next) != prev)
2690 remaints = unlink_insn_chain (prev, next);
2692 while (NEXT_INSN (insn))
2693 insn = NEXT_INSN (insn);
2694 NEXT_INSN (insn) = *to;
2696 PREV_INSN (*to) = insn;
2701 /* Return true when blocks A and B can be safely merged. */
2703 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2705 /* If we are partitioning hot/cold basic blocks, we don't want to
2706 mess up unconditional or indirect jumps that cross between hot
2709 Basic block partitioning may result in some jumps that appear to
2710 be optimizable (or blocks that appear to be mergeable), but which really
2711 must be left untouched (they are required to make it safely across
2712 partition boundaries). See the comments at the top of
2713 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2715 if (BB_PARTITION (a) != BB_PARTITION (b))
2718 /* There must be exactly one edge in between the blocks. */
2719 return (single_succ_p (a)
2720 && single_succ (a) == b
2721 && single_pred_p (b) == 1
2723 /* Must be simple edge. */
2724 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2725 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2726 /* If the jump insn has side effects,
2727 we can't kill the edge. */
2728 && (!JUMP_P (BB_END (a))
2729 || (reload_completed
2730 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2733 /* Merge block A and B. The blocks must be mergeable. */
2736 cfg_layout_merge_blocks (basic_block a, basic_block b)
2738 #ifdef ENABLE_CHECKING
2739 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2742 /* If there was a CODE_LABEL beginning B, delete it. */
2743 if (LABEL_P (BB_HEAD (b)))
2745 /* This might have been an EH label that no longer has incoming
2746 EH edges. Update data structures to match. */
2747 maybe_remove_eh_handler (BB_HEAD (b));
2749 delete_insn (BB_HEAD (b));
2752 /* We should have fallthru edge in a, or we can do dummy redirection to get
2754 if (JUMP_P (BB_END (a)))
2755 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2756 gcc_assert (!JUMP_P (BB_END (a)));
2758 /* Possible line number notes should appear in between. */
2759 if (b->il.rtl->header)
2761 rtx first = BB_END (a), last;
2763 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a));
2764 delete_insn_chain (NEXT_INSN (first), last);
2765 b->il.rtl->header = NULL;
2768 /* In the case basic blocks are not adjacent, move them around. */
2769 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2771 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2773 emit_insn_after_noloc (first, BB_END (a));
2774 /* Skip possible DELETED_LABEL insn. */
2775 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2776 first = NEXT_INSN (first);
2777 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2779 delete_insn (first);
2781 /* Otherwise just re-associate the instructions. */
2786 for (insn = BB_HEAD (b);
2787 insn != NEXT_INSN (BB_END (b));
2788 insn = NEXT_INSN (insn))
2789 set_block_for_insn (insn, a);
2791 /* Skip possible DELETED_LABEL insn. */
2792 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2793 insn = NEXT_INSN (insn);
2794 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2796 BB_END (a) = BB_END (b);
2800 /* Possible tablejumps and barriers should appear after the block. */
2801 if (b->il.rtl->footer)
2803 if (!a->il.rtl->footer)
2804 a->il.rtl->footer = b->il.rtl->footer;
2807 rtx last = a->il.rtl->footer;
2809 while (NEXT_INSN (last))
2810 last = NEXT_INSN (last);
2811 NEXT_INSN (last) = b->il.rtl->footer;
2812 PREV_INSN (b->il.rtl->footer) = last;
2814 b->il.rtl->footer = NULL;
2816 a->il.rtl->global_live_at_end = b->il.rtl->global_live_at_end;
2819 fprintf (dump_file, "Merged blocks %d and %d.\n",
2820 a->index, b->index);
2826 cfg_layout_split_edge (edge e)
2828 basic_block new_bb =
2829 create_basic_block (e->src != ENTRY_BLOCK_PTR
2830 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2833 /* ??? This info is likely going to be out of date very soon, but we must
2834 create it to avoid getting an ICE later. */
2835 if (e->dest->il.rtl->global_live_at_start)
2837 new_bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
2838 new_bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
2839 COPY_REG_SET (new_bb->il.rtl->global_live_at_start,
2840 e->dest->il.rtl->global_live_at_start);
2841 COPY_REG_SET (new_bb->il.rtl->global_live_at_end,
2842 e->dest->il.rtl->global_live_at_start);
2845 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2846 redirect_edge_and_branch_force (e, new_bb);
2851 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2854 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2858 /* Return 1 if BB ends with a call, possibly followed by some
2859 instructions that must stay with the call, 0 otherwise. */
2862 rtl_block_ends_with_call_p (basic_block bb)
2864 rtx insn = BB_END (bb);
2866 while (!CALL_P (insn)
2867 && insn != BB_HEAD (bb)
2868 && keep_with_call_p (insn))
2869 insn = PREV_INSN (insn);
2870 return (CALL_P (insn));
2873 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2876 rtl_block_ends_with_condjump_p (basic_block bb)
2878 return any_condjump_p (BB_END (bb));
2881 /* Return true if we need to add fake edge to exit.
2882 Helper function for rtl_flow_call_edges_add. */
2885 need_fake_edge_p (rtx insn)
2891 && !SIBLING_CALL_P (insn)
2892 && !find_reg_note (insn, REG_NORETURN, NULL)
2893 && !CONST_OR_PURE_CALL_P (insn)))
2896 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2897 && MEM_VOLATILE_P (PATTERN (insn)))
2898 || (GET_CODE (PATTERN (insn)) == PARALLEL
2899 && asm_noperands (insn) != -1
2900 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2901 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2904 /* Add fake edges to the function exit for any non constant and non noreturn
2905 calls, volatile inline assembly in the bitmap of blocks specified by
2906 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2909 The goal is to expose cases in which entering a basic block does not imply
2910 that all subsequent instructions must be executed. */
2913 rtl_flow_call_edges_add (sbitmap blocks)
2916 int blocks_split = 0;
2917 int last_bb = last_basic_block;
2918 bool check_last_block = false;
2920 if (n_basic_blocks == NUM_FIXED_BLOCKS)
2924 check_last_block = true;
2926 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2928 /* In the last basic block, before epilogue generation, there will be
2929 a fallthru edge to EXIT. Special care is required if the last insn
2930 of the last basic block is a call because make_edge folds duplicate
2931 edges, which would result in the fallthru edge also being marked
2932 fake, which would result in the fallthru edge being removed by
2933 remove_fake_edges, which would result in an invalid CFG.
2935 Moreover, we can't elide the outgoing fake edge, since the block
2936 profiler needs to take this into account in order to solve the minimal
2937 spanning tree in the case that the call doesn't return.
2939 Handle this by adding a dummy instruction in a new last basic block. */
2940 if (check_last_block)
2942 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2943 rtx insn = BB_END (bb);
2945 /* Back up past insns that must be kept in the same block as a call. */
2946 while (insn != BB_HEAD (bb)
2947 && keep_with_call_p (insn))
2948 insn = PREV_INSN (insn);
2950 if (need_fake_edge_p (insn))
2954 e = find_edge (bb, EXIT_BLOCK_PTR);
2957 insert_insn_on_edge (gen_rtx_USE (VOIDmode, const0_rtx), e);
2958 commit_edge_insertions ();
2963 /* Now add fake edges to the function exit for any non constant
2964 calls since there is no way that we can determine if they will
2967 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
2969 basic_block bb = BASIC_BLOCK (i);
2976 if (blocks && !TEST_BIT (blocks, i))
2979 for (insn = BB_END (bb); ; insn = prev_insn)
2981 prev_insn = PREV_INSN (insn);
2982 if (need_fake_edge_p (insn))
2985 rtx split_at_insn = insn;
2987 /* Don't split the block between a call and an insn that should
2988 remain in the same block as the call. */
2990 while (split_at_insn != BB_END (bb)
2991 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2992 split_at_insn = NEXT_INSN (split_at_insn);
2994 /* The handling above of the final block before the epilogue
2995 should be enough to verify that there is no edge to the exit
2996 block in CFG already. Calling make_edge in such case would
2997 cause us to mark that edge as fake and remove it later. */
2999 #ifdef ENABLE_CHECKING
3000 if (split_at_insn == BB_END (bb))
3002 e = find_edge (bb, EXIT_BLOCK_PTR);
3003 gcc_assert (e == NULL);
3007 /* Note that the following may create a new basic block
3008 and renumber the existing basic blocks. */
3009 if (split_at_insn != BB_END (bb))
3011 e = split_block (bb, split_at_insn);
3016 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
3019 if (insn == BB_HEAD (bb))
3025 verify_flow_info ();
3027 return blocks_split;
3030 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
3031 the conditional branch target, SECOND_HEAD should be the fall-thru
3032 there is no need to handle this here the loop versioning code handles
3033 this. the reason for SECON_HEAD is that it is needed for condition
3034 in trees, and this should be of the same type since it is a hook. */
3036 rtl_lv_add_condition_to_bb (basic_block first_head ,
3037 basic_block second_head ATTRIBUTE_UNUSED,
3038 basic_block cond_bb, void *comp_rtx)
3040 rtx label, seq, jump;
3041 rtx op0 = XEXP ((rtx)comp_rtx, 0);
3042 rtx op1 = XEXP ((rtx)comp_rtx, 1);
3043 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
3044 enum machine_mode mode;
3047 label = block_label (first_head);
3048 mode = GET_MODE (op0);
3049 if (mode == VOIDmode)
3050 mode = GET_MODE (op1);
3053 op0 = force_operand (op0, NULL_RTX);
3054 op1 = force_operand (op1, NULL_RTX);
3055 do_compare_rtx_and_jump (op0, op1, comp, 0,
3056 mode, NULL_RTX, NULL_RTX, label);
3057 jump = get_last_insn ();
3058 JUMP_LABEL (jump) = label;
3059 LABEL_NUSES (label)++;
3063 /* Add the new cond , in the new head. */
3064 emit_insn_after(seq, BB_END(cond_bb));
3068 /* Given a block B with unconditional branch at its end, get the
3069 store the return the branch edge and the fall-thru edge in
3070 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3072 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
3073 edge *fallthru_edge)
3075 edge e = EDGE_SUCC (b, 0);
3077 if (e->flags & EDGE_FALLTHRU)
3080 *branch_edge = EDGE_SUCC (b, 1);
3085 *fallthru_edge = EDGE_SUCC (b, 1);
3090 init_rtl_bb_info (basic_block bb)
3092 gcc_assert (!bb->il.rtl);
3093 bb->il.rtl = ggc_alloc_cleared (sizeof (struct rtl_bb_info));
3097 /* Implementation of CFG manipulation for linearized RTL. */
3098 struct cfg_hooks rtl_cfg_hooks = {
3100 rtl_verify_flow_info,
3102 rtl_create_basic_block,
3103 rtl_redirect_edge_and_branch,
3104 rtl_redirect_edge_and_branch_force,
3107 rtl_move_block_after,
3108 rtl_can_merge_blocks, /* can_merge_blocks_p */
3112 NULL, /* can_duplicate_block_p */
3113 NULL, /* duplicate_block */
3115 rtl_make_forwarder_block,
3116 rtl_tidy_fallthru_edge,
3117 rtl_block_ends_with_call_p,
3118 rtl_block_ends_with_condjump_p,
3119 rtl_flow_call_edges_add,
3120 NULL, /* execute_on_growing_pred */
3121 NULL, /* execute_on_shrinking_pred */
3122 NULL, /* duplicate loop for trees */
3123 NULL, /* lv_add_condition_to_bb */
3124 NULL, /* lv_adjust_loop_header_phi*/
3125 NULL, /* extract_cond_bb_edges */
3126 NULL /* flush_pending_stmts */
3129 /* Implementation of CFG manipulation for cfg layout RTL, where
3130 basic block connected via fallthru edges does not have to be adjacent.
3131 This representation will hopefully become the default one in future
3132 version of the compiler. */
3134 /* We do not want to declare these functions in a header file, since they
3135 should only be used through the cfghooks interface, and we do not want to
3136 move them here since it would require also moving quite a lot of related
3138 extern bool cfg_layout_can_duplicate_bb_p (basic_block);
3139 extern basic_block cfg_layout_duplicate_bb (basic_block);
3141 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3143 rtl_verify_flow_info_1,
3145 cfg_layout_create_basic_block,
3146 cfg_layout_redirect_edge_and_branch,
3147 cfg_layout_redirect_edge_and_branch_force,
3148 cfg_layout_delete_block,
3149 cfg_layout_split_block,
3150 rtl_move_block_after,
3151 cfg_layout_can_merge_blocks_p,
3152 cfg_layout_merge_blocks,
3155 cfg_layout_can_duplicate_bb_p,
3156 cfg_layout_duplicate_bb,
3157 cfg_layout_split_edge,
3158 rtl_make_forwarder_block,
3160 rtl_block_ends_with_call_p,
3161 rtl_block_ends_with_condjump_p,
3162 rtl_flow_call_edges_add,
3163 NULL, /* execute_on_growing_pred */
3164 NULL, /* execute_on_shrinking_pred */
3165 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3166 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3167 NULL, /* lv_adjust_loop_header_phi*/
3168 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3169 NULL /* flush_pending_stmts */