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, 2006, 2007, 2008, 2009, 2010,
4 2011, 2012 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
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
33 - CFG fixing after coarse manipulation
36 Functions not supposed for generic use:
37 - Infrastructure to determine quickly basic block for insn
38 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
39 - Edge redirection with updating and optimizing of insn chain
40 block_label, tidy_fallthru_edge, force_nonfallthru */
44 #include "coretypes.h"
47 #include "hard-reg-set.h"
48 #include "basic-block.h"
54 #include "rtl-error.h"
57 #include "insn-attr.h"
58 #include "insn-config.h"
59 #include "cfglayout.h"
62 #include "common/common-target.h"
65 #include "tree-pass.h"
68 static int can_delete_note_p (const_rtx);
69 static int can_delete_label_p (const_rtx);
70 static basic_block rtl_split_edge (edge);
71 static bool rtl_move_block_after (basic_block, basic_block);
72 static int rtl_verify_flow_info (void);
73 static basic_block cfg_layout_split_block (basic_block, void *);
74 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
75 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
76 static void cfg_layout_delete_block (basic_block);
77 static void rtl_delete_block (basic_block);
78 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
79 static edge rtl_redirect_edge_and_branch (edge, basic_block);
80 static basic_block rtl_split_block (basic_block, void *);
81 static void rtl_dump_bb (basic_block, FILE *, int, int);
82 static int rtl_verify_flow_info_1 (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 (const_rtx note)
91 switch (NOTE_KIND (note))
93 case NOTE_INSN_DELETED:
94 case NOTE_INSN_BASIC_BLOCK:
95 case NOTE_INSN_EPILOGUE_BEG:
103 /* True if a given label can be deleted. */
106 can_delete_label_p (const_rtx label)
108 return (!LABEL_PRESERVE_P (label)
109 /* User declared labels must be preserved. */
110 && LABEL_NAME (label) == 0
111 && !in_expr_list_p (forced_labels, label));
114 /* Delete INSN by patching it out. */
117 delete_insn (rtx insn)
120 bool really_delete = true;
124 /* Some labels can't be directly removed from the INSN chain, as they
125 might be references via variables, constant pool etc.
126 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
127 if (! can_delete_label_p (insn))
129 const char *name = LABEL_NAME (insn);
130 basic_block bb = BLOCK_FOR_INSN (insn);
131 rtx bb_note = NEXT_INSN (insn);
133 really_delete = false;
134 PUT_CODE (insn, NOTE);
135 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
136 NOTE_DELETED_LABEL_NAME (insn) = name;
138 if (bb_note != NULL_RTX && NOTE_INSN_BASIC_BLOCK_P (bb_note)
139 && BLOCK_FOR_INSN (bb_note) == bb)
141 reorder_insns_nobb (insn, insn, bb_note);
142 BB_HEAD (bb) = bb_note;
143 if (BB_END (bb) == bb_note)
148 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
153 /* If this insn has already been deleted, something is very wrong. */
154 gcc_assert (!INSN_DELETED_P (insn));
156 INSN_DELETED_P (insn) = 1;
159 /* If deleting a jump, decrement the use count of the label. Deleting
160 the label itself should happen in the normal course of block merging. */
163 if (JUMP_LABEL (insn)
164 && LABEL_P (JUMP_LABEL (insn)))
165 LABEL_NUSES (JUMP_LABEL (insn))--;
167 /* If there are more targets, remove them too. */
169 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
170 && LABEL_P (XEXP (note, 0)))
172 LABEL_NUSES (XEXP (note, 0))--;
173 remove_note (insn, note);
177 /* Also if deleting any insn that references a label as an operand. */
178 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
179 && LABEL_P (XEXP (note, 0)))
181 LABEL_NUSES (XEXP (note, 0))--;
182 remove_note (insn, note);
185 if (JUMP_TABLE_DATA_P (insn))
187 rtx pat = PATTERN (insn);
188 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
189 int len = XVECLEN (pat, diff_vec_p);
192 for (i = 0; i < len; i++)
194 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
196 /* When deleting code in bulk (e.g. removing many unreachable
197 blocks) we can delete a label that's a target of the vector
198 before deleting the vector itself. */
200 LABEL_NUSES (label)--;
205 /* Like delete_insn but also purge dead edges from BB. */
208 delete_insn_and_edges (rtx insn)
213 && BLOCK_FOR_INSN (insn)
214 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
218 purge_dead_edges (BLOCK_FOR_INSN (insn));
221 /* Unlink a chain of insns between START and FINISH, leaving notes
222 that must be paired. If CLEAR_BB is true, we set bb field for
223 insns that cannot be removed to NULL. */
226 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
230 /* Unchain the insns one by one. It would be quicker to delete all of these
231 with a single unchaining, rather than one at a time, but we need to keep
236 prev = PREV_INSN (current);
237 if (NOTE_P (current) && !can_delete_note_p (current))
240 delete_insn (current);
242 if (clear_bb && !INSN_DELETED_P (current))
243 set_block_for_insn (current, NULL);
245 if (current == start)
251 /* Create a new basic block consisting of the instructions between HEAD and END
252 inclusive. This function is designed to allow fast BB construction - reuses
253 the note and basic block struct in BB_NOTE, if any and do not grow
254 BASIC_BLOCK chain and should be used directly only by CFG construction code.
255 END can be NULL in to create new empty basic block before HEAD. Both END
256 and HEAD can be NULL to create basic block at the end of INSN chain.
257 AFTER is the basic block we should be put after. */
260 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
265 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
268 /* If we found an existing note, thread it back onto the chain. */
276 after = PREV_INSN (head);
280 if (after != bb_note && NEXT_INSN (after) != bb_note)
281 reorder_insns_nobb (bb_note, bb_note, after);
285 /* Otherwise we must create a note and a basic block structure. */
289 init_rtl_bb_info (bb);
292 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
293 else if (LABEL_P (head) && end)
295 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
301 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
307 NOTE_BASIC_BLOCK (bb_note) = bb;
310 /* Always include the bb note in the block. */
311 if (NEXT_INSN (end) == bb_note)
316 bb->index = last_basic_block++;
317 bb->flags = BB_NEW | BB_RTL;
318 link_block (bb, after);
319 SET_BASIC_BLOCK (bb->index, bb);
320 df_bb_refs_record (bb->index, false);
321 update_bb_for_insn (bb);
322 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
324 /* Tag the block so that we know it has been used when considering
325 other basic block notes. */
331 /* Create new basic block consisting of instructions in between HEAD and END
332 and place it to the BB chain after block AFTER. END can be NULL to
333 create a new empty basic block before HEAD. Both END and HEAD can be
334 NULL to create basic block at the end of INSN chain. */
337 rtl_create_basic_block (void *headp, void *endp, basic_block after)
339 rtx head = (rtx) headp, end = (rtx) endp;
342 /* Grow the basic block array if needed. */
343 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
345 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
346 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
351 bb = create_basic_block_structure (head, end, NULL, after);
357 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
359 basic_block newbb = rtl_create_basic_block (head, end, after);
364 /* Delete the insns in a (non-live) block. We physically delete every
365 non-deleted-note insn, and update the flow graph appropriately.
367 Return nonzero if we deleted an exception handler. */
369 /* ??? Preserving all such notes strikes me as wrong. It would be nice
370 to post-process the stream to remove empty blocks, loops, ranges, etc. */
373 rtl_delete_block (basic_block b)
377 /* If the head of this block is a CODE_LABEL, then it might be the
378 label for an exception handler which can't be reached. We need
379 to remove the label from the exception_handler_label list. */
382 end = get_last_bb_insn (b);
384 /* Selectively delete the entire chain. */
386 delete_insn_chain (insn, end, true);
390 fprintf (dump_file, "deleting block %d\n", b->index);
391 df_bb_delete (b->index);
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;
428 rest_of_pass_free_cfg (void)
431 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
432 valid at that point so it would be too late to call df_analyze. */
433 if (optimize > 0 && flag_delayed_branch)
435 df_note_add_problem ();
444 struct rtl_opt_pass pass_free_cfg =
448 "*free_cfg", /* name */
450 rest_of_pass_free_cfg, /* execute */
453 0, /* static_pass_number */
455 0, /* properties_required */
456 0, /* properties_provided */
457 PROP_cfg, /* properties_destroyed */
458 0, /* todo_flags_start */
459 0, /* todo_flags_finish */
463 /* Return RTX to emit after when we want to emit code on the entry of function. */
465 entry_of_function (void)
467 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
468 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
471 /* Emit INSN at the entry point of the function, ensuring that it is only
472 executed once per function. */
474 emit_insn_at_entry (rtx insn)
476 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
477 edge e = ei_safe_edge (ei);
478 gcc_assert (e->flags & EDGE_FALLTHRU);
480 insert_insn_on_edge (insn, e);
481 commit_edge_insertions ();
484 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
485 (or BARRIER if found) and notify df of the bb change.
486 The insn chain range is inclusive
487 (i.e. both BEGIN and END will be updated. */
490 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
494 end = NEXT_INSN (end);
495 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
496 if (!BARRIER_P (insn))
497 df_insn_change_bb (insn, bb);
500 /* Update BLOCK_FOR_INSN of insns in BB to BB,
501 and notify df of the change. */
504 update_bb_for_insn (basic_block bb)
506 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
510 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
512 bb_note (basic_block bb)
518 note = NEXT_INSN (note);
520 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note));
524 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
525 note associated with the BLOCK. */
528 first_insn_after_basic_block_note (basic_block block)
532 /* Get the first instruction in the block. */
533 insn = BB_HEAD (block);
535 if (insn == NULL_RTX)
538 insn = NEXT_INSN (insn);
539 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
541 return NEXT_INSN (insn);
544 /* Creates a new basic block just after basic block B by splitting
545 everything after specified instruction I. */
548 rtl_split_block (basic_block bb, void *insnp)
551 rtx insn = (rtx) insnp;
557 insn = first_insn_after_basic_block_note (bb);
563 insn = PREV_INSN (insn);
565 /* If the block contains only debug insns, insn would have
566 been NULL in a non-debug compilation, and then we'd end
567 up emitting a DELETED note. For -fcompare-debug
568 stability, emit the note too. */
569 if (insn != BB_END (bb)
570 && DEBUG_INSN_P (next)
571 && DEBUG_INSN_P (BB_END (bb)))
573 while (next != BB_END (bb) && DEBUG_INSN_P (next))
574 next = NEXT_INSN (next);
576 if (next == BB_END (bb))
577 emit_note_after (NOTE_INSN_DELETED, next);
581 insn = get_last_insn ();
584 /* We probably should check type of the insn so that we do not create
585 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
587 if (insn == BB_END (bb))
588 emit_note_after (NOTE_INSN_DELETED, insn);
590 /* Create the new basic block. */
591 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
592 BB_COPY_PARTITION (new_bb, bb);
595 /* Redirect the outgoing edges. */
596 new_bb->succs = bb->succs;
598 FOR_EACH_EDGE (e, ei, new_bb->succs)
601 /* The new block starts off being dirty. */
602 df_set_bb_dirty (bb);
606 /* Blocks A and B are to be merged into a single block A. The insns
607 are already contiguous. */
610 rtl_merge_blocks (basic_block a, basic_block b)
612 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
613 rtx del_first = NULL_RTX, del_last = NULL_RTX;
614 rtx b_debug_start = b_end, b_debug_end = b_end;
615 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
619 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
622 while (DEBUG_INSN_P (b_end))
623 b_end = PREV_INSN (b_debug_start = b_end);
625 /* If there was a CODE_LABEL beginning B, delete it. */
626 if (LABEL_P (b_head))
628 /* Detect basic blocks with nothing but a label. This can happen
629 in particular at the end of a function. */
633 del_first = del_last = b_head;
634 b_head = NEXT_INSN (b_head);
637 /* Delete the basic block note and handle blocks containing just that
639 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
647 b_head = NEXT_INSN (b_head);
650 /* If there was a jump out of A, delete it. */
655 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
657 || NOTE_INSN_BASIC_BLOCK_P (prev)
658 || prev == BB_HEAD (a))
664 /* If this was a conditional jump, we need to also delete
665 the insn that set cc0. */
666 if (only_sets_cc0_p (prev))
670 prev = prev_nonnote_insn (prev);
677 a_end = PREV_INSN (del_first);
679 else if (BARRIER_P (NEXT_INSN (a_end)))
680 del_first = NEXT_INSN (a_end);
682 /* Delete everything marked above as well as crap that might be
683 hanging out between the two blocks. */
685 delete_insn_chain (del_first, del_last, true);
687 /* Reassociate the insns of B with A. */
690 update_bb_for_insn_chain (a_end, b_debug_end, a);
694 else if (b_end != b_debug_end)
696 /* Move any deleted labels and other notes between the end of A
697 and the debug insns that make up B after the debug insns,
698 bringing the debug insns into A while keeping the notes after
700 if (NEXT_INSN (a_end) != b_debug_start)
701 reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
703 update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
707 df_bb_delete (b->index);
710 /* If B was a forwarder block, propagate the locus on the edge. */
711 if (forwarder_p && !EDGE_SUCC (b, 0)->goto_locus)
712 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
715 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
719 /* Return true when block A and B can be merged. */
722 rtl_can_merge_blocks (basic_block a, basic_block b)
724 /* If we are partitioning hot/cold basic blocks, we don't want to
725 mess up unconditional or indirect jumps that cross between hot
728 Basic block partitioning may result in some jumps that appear to
729 be optimizable (or blocks that appear to be mergeable), but which really
730 must be left untouched (they are required to make it safely across
731 partition boundaries). See the comments at the top of
732 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
734 if (BB_PARTITION (a) != BB_PARTITION (b))
737 /* Protect the loop latches. */
738 if (current_loops && b->loop_father->latch == b)
741 /* There must be exactly one edge in between the blocks. */
742 return (single_succ_p (a)
743 && single_succ (a) == b
746 /* Must be simple edge. */
747 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
749 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
750 /* If the jump insn has side effects,
751 we can't kill the edge. */
752 && (!JUMP_P (BB_END (a))
754 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
757 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
761 block_label (basic_block block)
763 if (block == EXIT_BLOCK_PTR)
766 if (!LABEL_P (BB_HEAD (block)))
768 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
771 return BB_HEAD (block);
774 /* Attempt to perform edge redirection by replacing possibly complex jump
775 instruction by unconditional jump or removing jump completely. This can
776 apply only if all edges now point to the same block. The parameters and
777 return values are equivalent to redirect_edge_and_branch. */
780 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
782 basic_block src = e->src;
783 rtx insn = BB_END (src), kill_from;
787 /* If we are partitioning hot/cold basic blocks, we don't want to
788 mess up unconditional or indirect jumps that cross between hot
791 Basic block partitioning may result in some jumps that appear to
792 be optimizable (or blocks that appear to be mergeable), but which really
793 must be left untouched (they are required to make it safely across
794 partition boundaries). See the comments at the top of
795 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
797 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
798 || BB_PARTITION (src) != BB_PARTITION (target))
801 /* We can replace or remove a complex jump only when we have exactly
802 two edges. Also, if we have exactly one outgoing edge, we can
804 if (EDGE_COUNT (src->succs) >= 3
805 /* Verify that all targets will be TARGET. Specifically, the
806 edge that is not E must also go to TARGET. */
807 || (EDGE_COUNT (src->succs) == 2
808 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
811 if (!onlyjump_p (insn))
813 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
816 /* Avoid removing branch with side effects. */
817 set = single_set (insn);
818 if (!set || side_effects_p (set))
821 /* In case we zap a conditional jump, we'll need to kill
822 the cc0 setter too. */
825 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
826 && only_sets_cc0_p (PREV_INSN (insn)))
827 kill_from = PREV_INSN (insn);
830 /* See if we can create the fallthru edge. */
831 if (in_cfglayout || can_fallthru (src, target))
834 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
837 /* Selectively unlink whole insn chain. */
840 rtx insn = src->il.rtl->footer;
842 delete_insn_chain (kill_from, BB_END (src), false);
844 /* Remove barriers but keep jumptables. */
847 if (BARRIER_P (insn))
849 if (PREV_INSN (insn))
850 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
852 src->il.rtl->footer = NEXT_INSN (insn);
853 if (NEXT_INSN (insn))
854 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
858 insn = NEXT_INSN (insn);
862 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
866 /* If this already is simplejump, redirect it. */
867 else if (simplejump_p (insn))
869 if (e->dest == target)
872 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
873 INSN_UID (insn), e->dest->index, target->index);
874 if (!redirect_jump (insn, block_label (target), 0))
876 gcc_assert (target == EXIT_BLOCK_PTR);
881 /* Cannot do anything for target exit block. */
882 else if (target == EXIT_BLOCK_PTR)
885 /* Or replace possibly complicated jump insn by simple jump insn. */
888 rtx target_label = block_label (target);
889 rtx barrier, label, table;
891 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
892 JUMP_LABEL (BB_END (src)) = target_label;
893 LABEL_NUSES (target_label)++;
895 fprintf (dump_file, "Replacing insn %i by jump %i\n",
896 INSN_UID (insn), INSN_UID (BB_END (src)));
899 delete_insn_chain (kill_from, insn, false);
901 /* Recognize a tablejump that we are converting to a
902 simple jump and remove its associated CODE_LABEL
903 and ADDR_VEC or ADDR_DIFF_VEC. */
904 if (tablejump_p (insn, &label, &table))
905 delete_insn_chain (label, table, false);
907 barrier = next_nonnote_insn (BB_END (src));
908 if (!barrier || !BARRIER_P (barrier))
909 emit_barrier_after (BB_END (src));
912 if (barrier != NEXT_INSN (BB_END (src)))
914 /* Move the jump before barrier so that the notes
915 which originally were or were created before jump table are
916 inside the basic block. */
917 rtx new_insn = BB_END (src);
919 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
920 PREV_INSN (barrier), src);
922 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
923 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
925 NEXT_INSN (new_insn) = barrier;
926 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
928 PREV_INSN (new_insn) = PREV_INSN (barrier);
929 PREV_INSN (barrier) = new_insn;
934 /* Keep only one edge out and set proper flags. */
935 if (!single_succ_p (src))
937 gcc_assert (single_succ_p (src));
939 e = single_succ_edge (src);
941 e->flags = EDGE_FALLTHRU;
945 e->probability = REG_BR_PROB_BASE;
946 e->count = src->count;
948 if (e->dest != target)
949 redirect_edge_succ (e, target);
953 /* Subroutine of redirect_branch_edge that tries to patch the jump
954 instruction INSN so that it reaches block NEW. Do this
955 only when it originally reached block OLD. Return true if this
956 worked or the original target wasn't OLD, return false if redirection
960 patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
963 /* Recognize a tablejump and adjust all matching cases. */
964 if (tablejump_p (insn, NULL, &tmp))
968 rtx new_label = block_label (new_bb);
970 if (new_bb == EXIT_BLOCK_PTR)
972 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
973 vec = XVEC (PATTERN (tmp), 0);
975 vec = XVEC (PATTERN (tmp), 1);
977 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
978 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
980 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
981 --LABEL_NUSES (old_label);
982 ++LABEL_NUSES (new_label);
985 /* Handle casesi dispatch insns. */
986 if ((tmp = single_set (insn)) != NULL
987 && SET_DEST (tmp) == pc_rtx
988 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
989 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
990 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
992 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
994 --LABEL_NUSES (old_label);
995 ++LABEL_NUSES (new_label);
998 else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
1000 int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
1001 rtx new_label, note;
1003 if (new_bb == EXIT_BLOCK_PTR)
1005 new_label = block_label (new_bb);
1007 for (i = 0; i < n; ++i)
1009 rtx old_ref = ASM_OPERANDS_LABEL (tmp, i);
1010 gcc_assert (GET_CODE (old_ref) == LABEL_REF);
1011 if (XEXP (old_ref, 0) == old_label)
1013 ASM_OPERANDS_LABEL (tmp, i)
1014 = gen_rtx_LABEL_REF (Pmode, new_label);
1015 --LABEL_NUSES (old_label);
1016 ++LABEL_NUSES (new_label);
1020 if (JUMP_LABEL (insn) == old_label)
1022 JUMP_LABEL (insn) = new_label;
1023 note = find_reg_note (insn, REG_LABEL_TARGET, new_label);
1025 remove_note (insn, note);
1029 note = find_reg_note (insn, REG_LABEL_TARGET, old_label);
1031 remove_note (insn, note);
1032 if (JUMP_LABEL (insn) != new_label
1033 && !find_reg_note (insn, REG_LABEL_TARGET, new_label))
1034 add_reg_note (insn, REG_LABEL_TARGET, new_label);
1036 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
1038 XEXP (note, 0) = new_label;
1042 /* ?? We may play the games with moving the named labels from
1043 one basic block to the other in case only one computed_jump is
1045 if (computed_jump_p (insn)
1046 /* A return instruction can't be redirected. */
1047 || returnjump_p (insn))
1050 if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
1052 /* If the insn doesn't go where we think, we're confused. */
1053 gcc_assert (JUMP_LABEL (insn) == old_label);
1055 /* If the substitution doesn't succeed, die. This can happen
1056 if the back end emitted unrecognizable instructions or if
1057 target is exit block on some arches. */
1058 if (!redirect_jump (insn, block_label (new_bb), 0))
1060 gcc_assert (new_bb == EXIT_BLOCK_PTR);
1069 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1072 redirect_branch_edge (edge e, basic_block target)
1074 rtx old_label = BB_HEAD (e->dest);
1075 basic_block src = e->src;
1076 rtx insn = BB_END (src);
1078 /* We can only redirect non-fallthru edges of jump insn. */
1079 if (e->flags & EDGE_FALLTHRU)
1081 else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
1084 if (!currently_expanding_to_rtl)
1086 if (!patch_jump_insn (insn, old_label, target))
1090 /* When expanding this BB might actually contain multiple
1091 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1092 Redirect all of those that match our label. */
1093 FOR_BB_INSNS (src, insn)
1094 if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target))
1098 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
1099 e->src->index, e->dest->index, target->index);
1101 if (e->dest != target)
1102 e = redirect_edge_succ_nodup (e, target);
1107 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1108 expense of adding new instructions or reordering basic blocks.
1110 Function can be also called with edge destination equivalent to the TARGET.
1111 Then it should try the simplifications and do nothing if none is possible.
1113 Return edge representing the branch if transformation succeeded. Return NULL
1115 We still return NULL in case E already destinated TARGET and we didn't
1116 managed to simplify instruction stream. */
1119 rtl_redirect_edge_and_branch (edge e, basic_block target)
1122 basic_block src = e->src;
1124 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1127 if (e->dest == target)
1130 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
1132 df_set_bb_dirty (src);
1136 ret = redirect_branch_edge (e, target);
1140 df_set_bb_dirty (src);
1144 /* Like force_nonfallthru below, but additionally performs redirection
1145 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1146 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1147 simple_return_rtx, indicating which kind of returnjump to create.
1148 It should be NULL otherwise. */
1151 force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label)
1153 basic_block jump_block, new_bb = NULL, src = e->src;
1156 int abnormal_edge_flags = 0;
1157 bool asm_goto_edge = false;
1160 /* In the case the last instruction is conditional jump to the next
1161 instruction, first redirect the jump itself and then continue
1162 by creating a basic block afterwards to redirect fallthru edge. */
1163 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1164 && any_condjump_p (BB_END (e->src))
1165 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1168 edge b = unchecked_make_edge (e->src, target, 0);
1171 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1172 gcc_assert (redirected);
1174 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1177 int prob = INTVAL (XEXP (note, 0));
1179 b->probability = prob;
1180 b->count = e->count * prob / REG_BR_PROB_BASE;
1181 e->probability -= e->probability;
1182 e->count -= b->count;
1183 if (e->probability < 0)
1190 if (e->flags & EDGE_ABNORMAL)
1192 /* Irritating special case - fallthru edge to the same block as abnormal
1194 We can't redirect abnormal edge, but we still can split the fallthru
1195 one and create separate abnormal edge to original destination.
1196 This allows bb-reorder to make such edge non-fallthru. */
1197 gcc_assert (e->dest == target);
1198 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1199 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1203 gcc_assert (e->flags & EDGE_FALLTHRU);
1204 if (e->src == ENTRY_BLOCK_PTR)
1206 /* We can't redirect the entry block. Create an empty block
1207 at the start of the function which we use to add the new
1213 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1215 /* Change the existing edge's source to be the new block, and add
1216 a new edge from the entry block to the new block. */
1218 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1222 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1232 VEC_safe_push (edge, gc, bb->succs, e);
1233 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1237 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1238 don't point to target label. */
1239 if (JUMP_P (BB_END (e->src))
1240 && target != EXIT_BLOCK_PTR
1241 && e->dest == target
1242 && (e->flags & EDGE_FALLTHRU)
1243 && (note = extract_asm_operands (PATTERN (BB_END (e->src)))))
1245 int i, n = ASM_OPERANDS_LABEL_LENGTH (note);
1247 for (i = 0; i < n; ++i)
1248 if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target))
1250 asm_goto_edge = true;
1255 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge)
1257 gcov_type count = e->count;
1258 int probability = e->probability;
1259 /* Create the new structures. */
1261 /* If the old block ended with a tablejump, skip its table
1262 by searching forward from there. Otherwise start searching
1263 forward from the last instruction of the old block. */
1264 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1265 note = BB_END (e->src);
1266 note = NEXT_INSN (note);
1268 jump_block = create_basic_block (note, NULL, e->src);
1269 jump_block->count = count;
1270 jump_block->frequency = EDGE_FREQUENCY (e);
1271 jump_block->loop_depth = target->loop_depth;
1273 /* Make sure new block ends up in correct hot/cold section. */
1275 BB_COPY_PARTITION (jump_block, e->src);
1276 if (flag_reorder_blocks_and_partition
1277 && targetm_common.have_named_sections
1278 && JUMP_P (BB_END (jump_block))
1279 && !any_condjump_p (BB_END (jump_block))
1280 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1281 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1284 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1285 new_edge->probability = probability;
1286 new_edge->count = count;
1288 /* Redirect old edge. */
1289 redirect_edge_pred (e, jump_block);
1290 e->probability = REG_BR_PROB_BASE;
1292 /* If asm goto has any label refs to target's label,
1293 add also edge from asm goto bb to target. */
1296 new_edge->probability /= 2;
1297 new_edge->count /= 2;
1298 jump_block->count /= 2;
1299 jump_block->frequency /= 2;
1300 new_edge = make_edge (new_edge->src, target,
1301 e->flags & ~EDGE_FALLTHRU);
1302 new_edge->probability = probability - probability / 2;
1303 new_edge->count = count - count / 2;
1306 new_bb = jump_block;
1309 jump_block = e->src;
1311 if (e->goto_locus && e->goto_block == NULL)
1312 loc = e->goto_locus;
1315 e->flags &= ~EDGE_FALLTHRU;
1316 if (target == EXIT_BLOCK_PTR)
1318 if (jump_label == ret_rtx)
1321 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1328 gcc_assert (jump_label == simple_return_rtx);
1329 #ifdef HAVE_simple_return
1330 emit_jump_insn_after_setloc (gen_simple_return (),
1331 BB_END (jump_block), loc);
1336 set_return_jump_label (BB_END (jump_block));
1340 rtx label = block_label (target);
1341 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1342 JUMP_LABEL (BB_END (jump_block)) = label;
1343 LABEL_NUSES (label)++;
1346 emit_barrier_after (BB_END (jump_block));
1347 redirect_edge_succ_nodup (e, target);
1349 if (abnormal_edge_flags)
1350 make_edge (src, target, abnormal_edge_flags);
1352 df_mark_solutions_dirty ();
1356 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1357 (and possibly create new basic block) to make edge non-fallthru.
1358 Return newly created BB or NULL if none. */
1361 rtl_force_nonfallthru (edge e)
1363 return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX);
1366 /* Redirect edge even at the expense of creating new jump insn or
1367 basic block. Return new basic block if created, NULL otherwise.
1368 Conversion must be possible. */
1371 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1373 if (redirect_edge_and_branch (e, target)
1374 || e->dest == target)
1377 /* In case the edge redirection failed, try to force it to be non-fallthru
1378 and redirect newly created simplejump. */
1379 df_set_bb_dirty (e->src);
1380 return force_nonfallthru_and_redirect (e, target, NULL_RTX);
1383 /* The given edge should potentially be a fallthru edge. If that is in
1384 fact true, delete the jump and barriers that are in the way. */
1387 rtl_tidy_fallthru_edge (edge e)
1390 basic_block b = e->src, c = b->next_bb;
1392 /* ??? In a late-running flow pass, other folks may have deleted basic
1393 blocks by nopping out blocks, leaving multiple BARRIERs between here
1394 and the target label. They ought to be chastised and fixed.
1396 We can also wind up with a sequence of undeletable labels between
1397 one block and the next.
1399 So search through a sequence of barriers, labels, and notes for
1400 the head of block C and assert that we really do fall through. */
1402 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1406 /* Remove what will soon cease being the jump insn from the source block.
1407 If block B consisted only of this single jump, turn it into a deleted
1412 && (any_uncondjump_p (q)
1413 || single_succ_p (b)))
1416 /* If this was a conditional jump, we need to also delete
1417 the insn that set cc0. */
1418 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1425 /* Selectively unlink the sequence. */
1426 if (q != PREV_INSN (BB_HEAD (c)))
1427 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1429 e->flags |= EDGE_FALLTHRU;
1432 /* Should move basic block BB after basic block AFTER. NIY. */
1435 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1436 basic_block after ATTRIBUTE_UNUSED)
1441 /* Split a (typically critical) edge. Return the new block.
1442 The edge must not be abnormal.
1444 ??? The code generally expects to be called on critical edges.
1445 The case of a block ending in an unconditional jump to a
1446 block with multiple predecessors is not handled optimally. */
1449 rtl_split_edge (edge edge_in)
1454 /* Abnormal edges cannot be split. */
1455 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1457 /* We are going to place the new block in front of edge destination.
1458 Avoid existence of fallthru predecessors. */
1459 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1461 edge e = find_fallthru_edge (edge_in->dest->preds);
1464 force_nonfallthru (e);
1467 /* Create the basic block note. */
1468 if (edge_in->dest != EXIT_BLOCK_PTR)
1469 before = BB_HEAD (edge_in->dest);
1473 /* If this is a fall through edge to the exit block, the blocks might be
1474 not adjacent, and the right place is after the source. */
1475 if ((edge_in->flags & EDGE_FALLTHRU) && edge_in->dest == EXIT_BLOCK_PTR)
1477 before = NEXT_INSN (BB_END (edge_in->src));
1478 bb = create_basic_block (before, NULL, edge_in->src);
1479 BB_COPY_PARTITION (bb, edge_in->src);
1483 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1484 /* ??? Why not edge_in->dest->prev_bb here? */
1485 BB_COPY_PARTITION (bb, edge_in->dest);
1488 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1490 /* For non-fallthru edges, we must adjust the predecessor's
1491 jump instruction to target our new block. */
1492 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1494 edge redirected = redirect_edge_and_branch (edge_in, bb);
1495 gcc_assert (redirected);
1499 if (edge_in->src != ENTRY_BLOCK_PTR)
1501 /* For asm goto even splitting of fallthru edge might
1502 need insn patching, as other labels might point to the
1504 rtx last = BB_END (edge_in->src);
1507 && edge_in->dest != EXIT_BLOCK_PTR
1508 && extract_asm_operands (PATTERN (last)) != NULL_RTX
1509 && patch_jump_insn (last, before, bb))
1510 df_set_bb_dirty (edge_in->src);
1512 redirect_edge_succ (edge_in, bb);
1518 /* Queue instructions for insertion on an edge between two basic blocks.
1519 The new instructions and basic blocks (if any) will not appear in the
1520 CFG until commit_edge_insertions is called. */
1523 insert_insn_on_edge (rtx pattern, edge e)
1525 /* We cannot insert instructions on an abnormal critical edge.
1526 It will be easier to find the culprit if we die now. */
1527 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1529 if (e->insns.r == NULL_RTX)
1532 push_to_sequence (e->insns.r);
1534 emit_insn (pattern);
1536 e->insns.r = get_insns ();
1540 /* Update the CFG for the instructions queued on edge E. */
1543 commit_one_edge_insertion (edge e)
1545 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1548 /* Pull the insns off the edge now since the edge might go away. */
1550 e->insns.r = NULL_RTX;
1552 /* Figure out where to put these insns. If the destination has
1553 one predecessor, insert there. Except for the exit block. */
1554 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1558 /* Get the location correct wrt a code label, and "nice" wrt
1559 a basic block note, and before everything else. */
1562 tmp = NEXT_INSN (tmp);
1563 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1564 tmp = NEXT_INSN (tmp);
1565 if (tmp == BB_HEAD (bb))
1568 after = PREV_INSN (tmp);
1570 after = get_last_insn ();
1573 /* If the source has one successor and the edge is not abnormal,
1574 insert there. Except for the entry block. */
1575 else if ((e->flags & EDGE_ABNORMAL) == 0
1576 && single_succ_p (e->src)
1577 && e->src != ENTRY_BLOCK_PTR)
1581 /* It is possible to have a non-simple jump here. Consider a target
1582 where some forms of unconditional jumps clobber a register. This
1583 happens on the fr30 for example.
1585 We know this block has a single successor, so we can just emit
1586 the queued insns before the jump. */
1587 if (JUMP_P (BB_END (bb)))
1588 before = BB_END (bb);
1591 /* We'd better be fallthru, or we've lost track of what's what. */
1592 gcc_assert (e->flags & EDGE_FALLTHRU);
1594 after = BB_END (bb);
1598 /* Otherwise we must split the edge. */
1601 bb = split_edge (e);
1602 after = BB_END (bb);
1604 if (flag_reorder_blocks_and_partition
1605 && targetm_common.have_named_sections
1606 && e->src != ENTRY_BLOCK_PTR
1607 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1608 && !(e->flags & EDGE_CROSSING)
1610 && !any_condjump_p (after)
1611 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1612 add_reg_note (after, REG_CROSSING_JUMP, NULL_RTX);
1615 /* Now that we've found the spot, do the insertion. */
1618 emit_insn_before_noloc (insns, before, bb);
1619 last = prev_nonnote_insn (before);
1622 last = emit_insn_after_noloc (insns, after, bb);
1624 if (returnjump_p (last))
1626 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1627 This is not currently a problem because this only happens
1628 for the (single) epilogue, which already has a fallthru edge
1631 e = single_succ_edge (bb);
1632 gcc_assert (e->dest == EXIT_BLOCK_PTR
1633 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1635 e->flags &= ~EDGE_FALLTHRU;
1636 emit_barrier_after (last);
1639 delete_insn (before);
1642 gcc_assert (!JUMP_P (last));
1645 /* Update the CFG for all queued instructions. */
1648 commit_edge_insertions (void)
1652 #ifdef ENABLE_CHECKING
1653 verify_flow_info ();
1656 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1661 FOR_EACH_EDGE (e, ei, bb->succs)
1663 commit_one_edge_insertion (e);
1668 /* Print out RTL-specific basic block information (live information
1669 at start and end). */
1672 rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED)
1678 s_indent = (char *) alloca ((size_t) indent + 1);
1679 memset (s_indent, ' ', (size_t) indent);
1680 s_indent[indent] = '\0';
1684 df_dump_top (bb, outf);
1688 if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK)
1689 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1690 insn = NEXT_INSN (insn))
1691 print_rtl_single (outf, insn);
1695 df_dump_bottom (bb, outf);
1701 /* Like print_rtl, but also print out live information for the start of each
1705 print_rtl_with_bb (FILE *outf, const_rtx rtx_first)
1709 fprintf (outf, "(nil)\n");
1712 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1713 int max_uid = get_max_uid ();
1714 basic_block *start = XCNEWVEC (basic_block, max_uid);
1715 basic_block *end = XCNEWVEC (basic_block, max_uid);
1716 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1721 df_dump_start (outf);
1723 FOR_EACH_BB_REVERSE (bb)
1727 start[INSN_UID (BB_HEAD (bb))] = bb;
1728 end[INSN_UID (BB_END (bb))] = bb;
1729 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1731 enum bb_state state = IN_MULTIPLE_BB;
1733 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1735 in_bb_p[INSN_UID (x)] = state;
1737 if (x == BB_END (bb))
1742 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1746 bb = start[INSN_UID (tmp_rtx)];
1748 dump_bb_info (bb, true, false, dump_flags, ";; ", outf);
1750 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1751 && !NOTE_P (tmp_rtx)
1752 && !BARRIER_P (tmp_rtx))
1753 fprintf (outf, ";; Insn is not within a basic block\n");
1754 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1755 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1757 did_output = print_rtl_single (outf, tmp_rtx);
1759 bb = end[INSN_UID (tmp_rtx)];
1761 dump_bb_info (bb, false, true, dump_flags, ";; ", outf);
1771 if (crtl->epilogue_delay_list != 0)
1773 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1774 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1775 tmp_rtx = XEXP (tmp_rtx, 1))
1776 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1781 update_br_prob_note (basic_block bb)
1784 if (!JUMP_P (BB_END (bb)))
1786 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1787 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1789 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1792 /* Get the last insn associated with block BB (that includes barriers and
1793 tablejumps after BB). */
1795 get_last_bb_insn (basic_block bb)
1798 rtx end = BB_END (bb);
1800 /* Include any jump table following the basic block. */
1801 if (tablejump_p (end, NULL, &tmp))
1804 /* Include any barriers that may follow the basic block. */
1805 tmp = next_nonnote_insn_bb (end);
1806 while (tmp && BARRIER_P (tmp))
1809 tmp = next_nonnote_insn_bb (end);
1815 /* Verify the CFG and RTL consistency common for both underlying RTL and
1818 Currently it does following checks:
1820 - overlapping of basic blocks
1821 - insns with wrong BLOCK_FOR_INSN pointers
1822 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1823 - tails of basic blocks (ensure that boundary is necessary)
1824 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1825 and NOTE_INSN_BASIC_BLOCK
1826 - verify that no fall_thru edge crosses hot/cold partition boundaries
1827 - verify that there are no pending RTL branch predictions
1829 In future it can be extended check a lot of other stuff as well
1830 (reachability of basic blocks, life information, etc. etc.). */
1833 rtl_verify_flow_info_1 (void)
1839 /* Check the general integrity of the basic blocks. */
1840 FOR_EACH_BB_REVERSE (bb)
1844 if (!(bb->flags & BB_RTL))
1846 error ("BB_RTL flag not set for block %d", bb->index);
1850 FOR_BB_INSNS (bb, insn)
1851 if (BLOCK_FOR_INSN (insn) != bb)
1853 error ("insn %d basic block pointer is %d, should be %d",
1855 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
1860 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
1861 if (!BARRIER_P (insn)
1862 && BLOCK_FOR_INSN (insn) != NULL)
1864 error ("insn %d in header of bb %d has non-NULL basic block",
1865 INSN_UID (insn), bb->index);
1868 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
1869 if (!BARRIER_P (insn)
1870 && BLOCK_FOR_INSN (insn) != NULL)
1872 error ("insn %d in footer of bb %d has non-NULL basic block",
1873 INSN_UID (insn), bb->index);
1878 /* Now check the basic blocks (boundaries etc.) */
1879 FOR_EACH_BB_REVERSE (bb)
1881 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1882 edge e, fallthru = NULL;
1886 if (JUMP_P (BB_END (bb))
1887 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1888 && EDGE_COUNT (bb->succs) >= 2
1889 && any_condjump_p (BB_END (bb)))
1891 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1892 && profile_status != PROFILE_ABSENT)
1894 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1895 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1899 FOR_EACH_EDGE (e, ei, bb->succs)
1903 if (e->flags & EDGE_FALLTHRU)
1904 n_fallthru++, fallthru = e;
1906 is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1907 && e->src != ENTRY_BLOCK_PTR
1908 && e->dest != EXIT_BLOCK_PTR);
1909 if (e->flags & EDGE_CROSSING)
1913 error ("EDGE_CROSSING incorrectly set across same section");
1916 if (e->flags & EDGE_FALLTHRU)
1918 error ("fallthru edge crosses section boundary (bb %i)",
1922 if (e->flags & EDGE_EH)
1924 error ("EH edge crosses section boundary (bb %i)",
1929 else if (is_crossing)
1931 error ("EDGE_CROSSING missing across section boundary");
1935 if ((e->flags & ~(EDGE_DFS_BACK
1937 | EDGE_IRREDUCIBLE_LOOP
1940 | EDGE_PRESERVE)) == 0)
1943 if (e->flags & EDGE_ABNORMAL_CALL)
1946 if (e->flags & EDGE_EH)
1948 else if (e->flags & EDGE_ABNORMAL)
1952 if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1954 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
1959 error ("too many eh edges %i", bb->index);
1963 && (!JUMP_P (BB_END (bb))
1964 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1965 || any_condjump_p (BB_END (bb))))))
1967 error ("too many outgoing branch edges from bb %i", bb->index);
1970 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1972 error ("fallthru edge after unconditional jump %i", bb->index);
1975 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1977 error ("wrong number of branch edges after unconditional jump %i",
1981 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1982 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1984 error ("wrong amount of branch edges after conditional jump %i",
1988 if (n_call && !CALL_P (BB_END (bb)))
1990 error ("call edges for non-call insn in bb %i", bb->index);
1994 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
1995 && (!JUMP_P (BB_END (bb))
1996 || any_condjump_p (BB_END (bb))
1997 || any_uncondjump_p (BB_END (bb))))
1999 error ("abnormal edges for no purpose in bb %i", bb->index);
2003 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
2004 /* We may have a barrier inside a basic block before dead code
2005 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2006 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
2009 if (! BLOCK_FOR_INSN (x))
2011 ("insn %d inside basic block %d but block_for_insn is NULL",
2012 INSN_UID (x), bb->index);
2015 ("insn %d inside basic block %d but block_for_insn is %i",
2016 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
2021 /* OK pointers are correct. Now check the header of basic
2022 block. It ought to contain optional CODE_LABEL followed
2023 by NOTE_BASIC_BLOCK. */
2027 if (BB_END (bb) == x)
2029 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2037 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
2039 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2044 if (BB_END (bb) == x)
2045 /* Do checks for empty blocks here. */
2048 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
2050 if (NOTE_INSN_BASIC_BLOCK_P (x))
2052 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2053 INSN_UID (x), bb->index);
2057 if (x == BB_END (bb))
2060 if (control_flow_insn_p (x))
2062 error ("in basic block %d:", bb->index);
2063 fatal_insn ("flow control insn inside a basic block", x);
2072 /* Verify the CFG and RTL consistency common for both underlying RTL and
2075 Currently it does following checks:
2076 - all checks of rtl_verify_flow_info_1
2077 - test head/end pointers
2078 - check that all insns are in the basic blocks
2079 (except the switch handling code, barriers and notes)
2080 - check that all returns are followed by barriers
2081 - check that all fallthru edge points to the adjacent blocks. */
2084 rtl_verify_flow_info (void)
2087 int err = rtl_verify_flow_info_1 ();
2089 rtx last_head = get_last_insn ();
2090 basic_block *bb_info;
2092 const rtx rtx_first = get_insns ();
2093 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2094 const int max_uid = get_max_uid ();
2096 bb_info = XCNEWVEC (basic_block, max_uid);
2098 FOR_EACH_BB_REVERSE (bb)
2101 rtx head = BB_HEAD (bb);
2102 rtx end = BB_END (bb);
2104 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2106 /* Verify the end of the basic block is in the INSN chain. */
2110 /* And that the code outside of basic blocks has NULL bb field. */
2112 && BLOCK_FOR_INSN (x) != NULL)
2114 error ("insn %d outside of basic blocks has non-NULL bb field",
2122 error ("end insn %d for block %d not found in the insn stream",
2123 INSN_UID (end), bb->index);
2127 /* Work backwards from the end to the head of the basic block
2128 to verify the head is in the RTL chain. */
2129 for (; x != NULL_RTX; x = PREV_INSN (x))
2131 /* While walking over the insn chain, verify insns appear
2132 in only one basic block. */
2133 if (bb_info[INSN_UID (x)] != NULL)
2135 error ("insn %d is in multiple basic blocks (%d and %d)",
2136 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2140 bb_info[INSN_UID (x)] = bb;
2147 error ("head insn %d for block %d not found in the insn stream",
2148 INSN_UID (head), bb->index);
2152 last_head = PREV_INSN (x);
2154 e = find_fallthru_edge (bb->succs);
2159 /* Ensure existence of barrier in BB with no fallthru edges. */
2160 for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn))
2162 if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn))
2164 error ("missing barrier after block %i", bb->index);
2168 if (BARRIER_P (insn))
2172 else if (e->src != ENTRY_BLOCK_PTR
2173 && e->dest != EXIT_BLOCK_PTR)
2177 if (e->src->next_bb != e->dest)
2180 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2181 e->src->index, e->dest->index);
2185 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2186 insn = NEXT_INSN (insn))
2187 if (BARRIER_P (insn) || INSN_P (insn))
2189 error ("verify_flow_info: Incorrect fallthru %i->%i",
2190 e->src->index, e->dest->index);
2191 fatal_insn ("wrong insn in the fallthru edge", insn);
2197 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2199 /* Check that the code before the first basic block has NULL
2202 && BLOCK_FOR_INSN (x) != NULL)
2204 error ("insn %d outside of basic blocks has non-NULL bb field",
2212 last_bb_seen = ENTRY_BLOCK_PTR;
2214 for (x = rtx_first; x; x = NEXT_INSN (x))
2216 if (NOTE_INSN_BASIC_BLOCK_P (x))
2218 bb = NOTE_BASIC_BLOCK (x);
2221 if (bb != last_bb_seen->next_bb)
2222 internal_error ("basic blocks not laid down consecutively");
2224 curr_bb = last_bb_seen = bb;
2229 switch (GET_CODE (x))
2236 /* An addr_vec is placed outside any basic block. */
2238 && JUMP_TABLE_DATA_P (NEXT_INSN (x)))
2241 /* But in any case, non-deletable labels can appear anywhere. */
2245 fatal_insn ("insn outside basic block", x);
2250 && returnjump_p (x) && ! condjump_p (x)
2251 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2252 fatal_insn ("return not followed by barrier", x);
2253 if (curr_bb && x == BB_END (curr_bb))
2257 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2259 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2260 num_bb_notes, n_basic_blocks);
2265 /* Assume that the preceding pass has possibly eliminated jump instructions
2266 or converted the unconditional jumps. Eliminate the edges from CFG.
2267 Return true if any edges are eliminated. */
2270 purge_dead_edges (basic_block bb)
2273 rtx insn = BB_END (bb), note;
2274 bool purged = false;
2278 if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb))
2280 insn = PREV_INSN (insn);
2281 while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
2283 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2284 if (NONJUMP_INSN_P (insn)
2285 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2289 if (! may_trap_p (PATTERN (insn))
2290 || ((eqnote = find_reg_equal_equiv_note (insn))
2291 && ! may_trap_p (XEXP (eqnote, 0))))
2292 remove_note (insn, note);
2295 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2296 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2298 bool remove = false;
2300 /* There are three types of edges we need to handle correctly here: EH
2301 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2302 latter can appear when nonlocal gotos are used. */
2303 if (e->flags & EDGE_ABNORMAL_CALL)
2307 else if (can_nonlocal_goto (insn))
2309 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2311 else if (flag_tm && find_reg_note (insn, REG_TM, NULL))
2316 else if (e->flags & EDGE_EH)
2317 remove = !can_throw_internal (insn);
2322 df_set_bb_dirty (bb);
2335 /* We do care only about conditional jumps and simplejumps. */
2336 if (!any_condjump_p (insn)
2337 && !returnjump_p (insn)
2338 && !simplejump_p (insn))
2341 /* Branch probability/prediction notes are defined only for
2342 condjumps. We've possibly turned condjump into simplejump. */
2343 if (simplejump_p (insn))
2345 note = find_reg_note (insn, REG_BR_PROB, NULL);
2347 remove_note (insn, note);
2348 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2349 remove_note (insn, note);
2352 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2354 /* Avoid abnormal flags to leak from computed jumps turned
2355 into simplejumps. */
2357 e->flags &= ~EDGE_ABNORMAL;
2359 /* See if this edge is one we should keep. */
2360 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2361 /* A conditional jump can fall through into the next
2362 block, so we should keep the edge. */
2367 else if (e->dest != EXIT_BLOCK_PTR
2368 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2369 /* If the destination block is the target of the jump,
2375 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2376 /* If the destination block is the exit block, and this
2377 instruction is a return, then keep the edge. */
2382 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2383 /* Keep the edges that correspond to exceptions thrown by
2384 this instruction and rematerialize the EDGE_ABNORMAL
2385 flag we just cleared above. */
2387 e->flags |= EDGE_ABNORMAL;
2392 /* We do not need this edge. */
2393 df_set_bb_dirty (bb);
2398 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2402 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2407 /* Redistribute probabilities. */
2408 if (single_succ_p (bb))
2410 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2411 single_succ_edge (bb)->count = bb->count;
2415 note = find_reg_note (insn, REG_BR_PROB, NULL);
2419 b = BRANCH_EDGE (bb);
2420 f = FALLTHRU_EDGE (bb);
2421 b->probability = INTVAL (XEXP (note, 0));
2422 f->probability = REG_BR_PROB_BASE - b->probability;
2423 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2424 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2429 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2431 /* First, there should not be any EH or ABCALL edges resulting
2432 from non-local gotos and the like. If there were, we shouldn't
2433 have created the sibcall in the first place. Second, there
2434 should of course never have been a fallthru edge. */
2435 gcc_assert (single_succ_p (bb));
2436 gcc_assert (single_succ_edge (bb)->flags
2437 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2442 /* If we don't see a jump insn, we don't know exactly why the block would
2443 have been broken at this point. Look for a simple, non-fallthru edge,
2444 as these are only created by conditional branches. If we find such an
2445 edge we know that there used to be a jump here and can then safely
2446 remove all non-fallthru edges. */
2448 FOR_EACH_EDGE (e, ei, bb->succs)
2449 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2458 /* Remove all but the fake and fallthru edges. The fake edge may be
2459 the only successor for this block in the case of noreturn
2461 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2463 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2465 df_set_bb_dirty (bb);
2473 gcc_assert (single_succ_p (bb));
2475 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2476 single_succ_edge (bb)->count = bb->count;
2479 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2484 /* Search all basic blocks for potentially dead edges and purge them. Return
2485 true if some edge has been eliminated. */
2488 purge_all_dead_edges (void)
2495 bool purged_here = purge_dead_edges (bb);
2497 purged |= purged_here;
2503 /* This is used by a few passes that emit some instructions after abnormal
2504 calls, moving the basic block's end, while they in fact do want to emit
2505 them on the fallthru edge. Look for abnormal call edges, find backward
2506 the call in the block and insert the instructions on the edge instead.
2508 Similarly, handle instructions throwing exceptions internally.
2510 Return true when instructions have been found and inserted on edges. */
2513 fixup_abnormal_edges (void)
2515 bool inserted = false;
2523 /* Look for cases we are interested in - calls or instructions causing
2525 FOR_EACH_EDGE (e, ei, bb->succs)
2526 if ((e->flags & EDGE_ABNORMAL_CALL)
2527 || ((e->flags & (EDGE_ABNORMAL | EDGE_EH))
2528 == (EDGE_ABNORMAL | EDGE_EH)))
2531 if (e && !CALL_P (BB_END (bb)) && !can_throw_internal (BB_END (bb)))
2535 /* Get past the new insns generated. Allow notes, as the insns
2536 may be already deleted. */
2538 while ((NONJUMP_INSN_P (insn) || NOTE_P (insn))
2539 && !can_throw_internal (insn)
2540 && insn != BB_HEAD (bb))
2541 insn = PREV_INSN (insn);
2543 if (CALL_P (insn) || can_throw_internal (insn))
2547 e = find_fallthru_edge (bb->succs);
2549 stop = NEXT_INSN (BB_END (bb));
2552 for (insn = NEXT_INSN (insn); insn != stop; insn = next)
2554 next = NEXT_INSN (insn);
2559 /* Sometimes there's still the return value USE.
2560 If it's placed after a trapping call (i.e. that
2561 call is the last insn anyway), we have no fallthru
2562 edge. Simply delete this use and don't try to insert
2563 on the non-existent edge. */
2564 if (GET_CODE (PATTERN (insn)) != USE)
2566 /* We're not deleting it, we're moving it. */
2567 INSN_DELETED_P (insn) = 0;
2568 PREV_INSN (insn) = NULL_RTX;
2569 NEXT_INSN (insn) = NULL_RTX;
2571 insert_insn_on_edge (insn, e);
2575 else if (!BARRIER_P (insn))
2576 set_block_for_insn (insn, NULL);
2580 /* It may be that we don't find any trapping insn. In this
2581 case we discovered quite late that the insn that had been
2582 marked as can_throw_internal in fact couldn't trap at all.
2583 So we should in fact delete the EH edges out of the block. */
2585 purge_dead_edges (bb);
2592 /* Same as split_block but update cfg_layout structures. */
2595 cfg_layout_split_block (basic_block bb, void *insnp)
2597 rtx insn = (rtx) insnp;
2598 basic_block new_bb = rtl_split_block (bb, insn);
2600 new_bb->il.rtl->footer = bb->il.rtl->footer;
2601 bb->il.rtl->footer = NULL;
2606 /* Redirect Edge to DEST. */
2608 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2610 basic_block src = e->src;
2613 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2616 if (e->dest == dest)
2619 if (e->src != ENTRY_BLOCK_PTR
2620 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2622 df_set_bb_dirty (src);
2626 if (e->src == ENTRY_BLOCK_PTR
2627 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2630 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2631 e->src->index, dest->index);
2633 df_set_bb_dirty (e->src);
2634 redirect_edge_succ (e, dest);
2638 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2639 in the case the basic block appears to be in sequence. Avoid this
2642 if (e->flags & EDGE_FALLTHRU)
2644 /* Redirect any branch edges unified with the fallthru one. */
2645 if (JUMP_P (BB_END (src))
2646 && label_is_jump_target_p (BB_HEAD (e->dest),
2652 fprintf (dump_file, "Fallthru edge unified with branch "
2653 "%i->%i redirected to %i\n",
2654 e->src->index, e->dest->index, dest->index);
2655 e->flags &= ~EDGE_FALLTHRU;
2656 redirected = redirect_branch_edge (e, dest);
2657 gcc_assert (redirected);
2658 redirected->flags |= EDGE_FALLTHRU;
2659 df_set_bb_dirty (redirected->src);
2662 /* In case we are redirecting fallthru edge to the branch edge
2663 of conditional jump, remove it. */
2664 if (EDGE_COUNT (src->succs) == 2)
2666 /* Find the edge that is different from E. */
2667 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2670 && any_condjump_p (BB_END (src))
2671 && onlyjump_p (BB_END (src)))
2672 delete_insn (BB_END (src));
2675 fprintf (dump_file, "Redirecting fallthru edge %i->%i to %i\n",
2676 e->src->index, e->dest->index, dest->index);
2677 ret = redirect_edge_succ_nodup (e, dest);
2680 ret = redirect_branch_edge (e, dest);
2682 /* We don't want simplejumps in the insn stream during cfglayout. */
2683 gcc_assert (!simplejump_p (BB_END (src)));
2685 df_set_bb_dirty (src);
2689 /* Simple wrapper as we always can redirect fallthru edges. */
2691 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2693 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2695 gcc_assert (redirected);
2699 /* Same as delete_basic_block but update cfg_layout structures. */
2702 cfg_layout_delete_block (basic_block bb)
2704 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2706 if (bb->il.rtl->header)
2708 next = BB_HEAD (bb);
2710 NEXT_INSN (prev) = bb->il.rtl->header;
2712 set_first_insn (bb->il.rtl->header);
2713 PREV_INSN (bb->il.rtl->header) = prev;
2714 insn = bb->il.rtl->header;
2715 while (NEXT_INSN (insn))
2716 insn = NEXT_INSN (insn);
2717 NEXT_INSN (insn) = next;
2718 PREV_INSN (next) = insn;
2720 next = NEXT_INSN (BB_END (bb));
2721 if (bb->il.rtl->footer)
2723 insn = bb->il.rtl->footer;
2726 if (BARRIER_P (insn))
2728 if (PREV_INSN (insn))
2729 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2731 bb->il.rtl->footer = NEXT_INSN (insn);
2732 if (NEXT_INSN (insn))
2733 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2737 insn = NEXT_INSN (insn);
2739 if (bb->il.rtl->footer)
2742 NEXT_INSN (insn) = bb->il.rtl->footer;
2743 PREV_INSN (bb->il.rtl->footer) = insn;
2744 while (NEXT_INSN (insn))
2745 insn = NEXT_INSN (insn);
2746 NEXT_INSN (insn) = next;
2748 PREV_INSN (next) = insn;
2750 set_last_insn (insn);
2753 if (bb->next_bb != EXIT_BLOCK_PTR)
2754 to = &bb->next_bb->il.rtl->header;
2756 to = &cfg_layout_function_footer;
2758 rtl_delete_block (bb);
2761 prev = NEXT_INSN (prev);
2763 prev = get_insns ();
2765 next = PREV_INSN (next);
2767 next = get_last_insn ();
2769 if (next && NEXT_INSN (next) != prev)
2771 remaints = unlink_insn_chain (prev, next);
2773 while (NEXT_INSN (insn))
2774 insn = NEXT_INSN (insn);
2775 NEXT_INSN (insn) = *to;
2777 PREV_INSN (*to) = insn;
2782 /* Return true when blocks A and B can be safely merged. */
2785 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2787 /* If we are partitioning hot/cold basic blocks, we don't want to
2788 mess up unconditional or indirect jumps that cross between hot
2791 Basic block partitioning may result in some jumps that appear to
2792 be optimizable (or blocks that appear to be mergeable), but which really
2793 must be left untouched (they are required to make it safely across
2794 partition boundaries). See the comments at the top of
2795 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2797 if (BB_PARTITION (a) != BB_PARTITION (b))
2800 /* Protect the loop latches. */
2801 if (current_loops && b->loop_father->latch == b)
2804 /* If we would end up moving B's instructions, make sure it doesn't fall
2805 through into the exit block, since we cannot recover from a fallthrough
2806 edge into the exit block occurring in the middle of a function. */
2807 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2809 edge e = find_fallthru_edge (b->succs);
2810 if (e && e->dest == EXIT_BLOCK_PTR)
2814 /* There must be exactly one edge in between the blocks. */
2815 return (single_succ_p (a)
2816 && single_succ (a) == b
2817 && single_pred_p (b) == 1
2819 /* Must be simple edge. */
2820 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2821 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2822 /* If the jump insn has side effects, we can't kill the edge.
2823 When not optimizing, try_redirect_by_replacing_jump will
2824 not allow us to redirect an edge by replacing a table jump. */
2825 && (!JUMP_P (BB_END (a))
2826 || ((!optimize || reload_completed)
2827 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2830 /* Merge block A and B. The blocks must be mergeable. */
2833 cfg_layout_merge_blocks (basic_block a, basic_block b)
2835 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
2838 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b));
2841 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
2844 /* If there was a CODE_LABEL beginning B, delete it. */
2845 if (LABEL_P (BB_HEAD (b)))
2847 delete_insn (BB_HEAD (b));
2850 /* We should have fallthru edge in a, or we can do dummy redirection to get
2852 if (JUMP_P (BB_END (a)))
2853 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2854 gcc_assert (!JUMP_P (BB_END (a)));
2856 /* When not optimizing and the edge is the only place in RTL which holds
2857 some unique locus, emit a nop with that locus in between. */
2858 if (!optimize && EDGE_SUCC (a, 0)->goto_locus)
2860 rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a));
2861 int goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2863 while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0))
2864 insn = PREV_INSN (insn);
2865 if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus))
2870 end = NEXT_INSN (BB_END (b));
2871 while (insn != end && !INSN_P (insn))
2872 insn = NEXT_INSN (insn);
2873 if (insn != end && INSN_LOCATOR (insn) != 0
2874 && locator_eq (INSN_LOCATOR (insn), goto_locus))
2879 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
2880 INSN_LOCATOR (BB_END (a)) = goto_locus;
2884 /* Possible line number notes should appear in between. */
2885 if (b->il.rtl->header)
2887 rtx first = BB_END (a), last;
2889 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a);
2890 /* The above might add a BARRIER as BB_END, but as barriers
2891 aren't valid parts of a bb, remove_insn doesn't update
2892 BB_END if it is a barrier. So adjust BB_END here. */
2893 while (BB_END (a) != first && BARRIER_P (BB_END (a)))
2894 BB_END (a) = PREV_INSN (BB_END (a));
2895 delete_insn_chain (NEXT_INSN (first), last, false);
2896 b->il.rtl->header = NULL;
2899 /* In the case basic blocks are not adjacent, move them around. */
2900 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2902 insn = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2904 emit_insn_after_noloc (insn, BB_END (a), a);
2906 /* Otherwise just re-associate the instructions. */
2910 BB_END (a) = BB_END (b);
2913 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2914 We need to explicitly call. */
2915 update_bb_for_insn_chain (insn, BB_END (b), a);
2917 /* Skip possible DELETED_LABEL insn. */
2918 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2919 insn = NEXT_INSN (insn);
2920 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2924 df_bb_delete (b->index);
2926 /* Possible tablejumps and barriers should appear after the block. */
2927 if (b->il.rtl->footer)
2929 if (!a->il.rtl->footer)
2930 a->il.rtl->footer = b->il.rtl->footer;
2933 rtx last = a->il.rtl->footer;
2935 while (NEXT_INSN (last))
2936 last = NEXT_INSN (last);
2937 NEXT_INSN (last) = b->il.rtl->footer;
2938 PREV_INSN (b->il.rtl->footer) = last;
2940 b->il.rtl->footer = NULL;
2943 /* If B was a forwarder block, propagate the locus on the edge. */
2944 if (forwarder_p && !EDGE_SUCC (b, 0)->goto_locus)
2945 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2948 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
2954 cfg_layout_split_edge (edge e)
2956 basic_block new_bb =
2957 create_basic_block (e->src != ENTRY_BLOCK_PTR
2958 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2961 if (e->dest == EXIT_BLOCK_PTR)
2962 BB_COPY_PARTITION (new_bb, e->src);
2964 BB_COPY_PARTITION (new_bb, e->dest);
2965 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2966 redirect_edge_and_branch_force (e, new_bb);
2971 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2974 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2978 /* Return 1 if BB ends with a call, possibly followed by some
2979 instructions that must stay with the call, 0 otherwise. */
2982 rtl_block_ends_with_call_p (basic_block bb)
2984 rtx insn = BB_END (bb);
2986 while (!CALL_P (insn)
2987 && insn != BB_HEAD (bb)
2988 && (keep_with_call_p (insn)
2990 || DEBUG_INSN_P (insn)))
2991 insn = PREV_INSN (insn);
2992 return (CALL_P (insn));
2995 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2998 rtl_block_ends_with_condjump_p (const_basic_block bb)
3000 return any_condjump_p (BB_END (bb));
3003 /* Return true if we need to add fake edge to exit.
3004 Helper function for rtl_flow_call_edges_add. */
3007 need_fake_edge_p (const_rtx insn)
3013 && !SIBLING_CALL_P (insn)
3014 && !find_reg_note (insn, REG_NORETURN, NULL)
3015 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
3018 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
3019 && MEM_VOLATILE_P (PATTERN (insn)))
3020 || (GET_CODE (PATTERN (insn)) == PARALLEL
3021 && asm_noperands (insn) != -1
3022 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
3023 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
3026 /* Add fake edges to the function exit for any non constant and non noreturn
3027 calls, volatile inline assembly in the bitmap of blocks specified by
3028 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
3031 The goal is to expose cases in which entering a basic block does not imply
3032 that all subsequent instructions must be executed. */
3035 rtl_flow_call_edges_add (sbitmap blocks)
3038 int blocks_split = 0;
3039 int last_bb = last_basic_block;
3040 bool check_last_block = false;
3042 if (n_basic_blocks == NUM_FIXED_BLOCKS)
3046 check_last_block = true;
3048 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
3050 /* In the last basic block, before epilogue generation, there will be
3051 a fallthru edge to EXIT. Special care is required if the last insn
3052 of the last basic block is a call because make_edge folds duplicate
3053 edges, which would result in the fallthru edge also being marked
3054 fake, which would result in the fallthru edge being removed by
3055 remove_fake_edges, which would result in an invalid CFG.
3057 Moreover, we can't elide the outgoing fake edge, since the block
3058 profiler needs to take this into account in order to solve the minimal
3059 spanning tree in the case that the call doesn't return.
3061 Handle this by adding a dummy instruction in a new last basic block. */
3062 if (check_last_block)
3064 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
3065 rtx insn = BB_END (bb);
3067 /* Back up past insns that must be kept in the same block as a call. */
3068 while (insn != BB_HEAD (bb)
3069 && keep_with_call_p (insn))
3070 insn = PREV_INSN (insn);
3072 if (need_fake_edge_p (insn))
3076 e = find_edge (bb, EXIT_BLOCK_PTR);
3079 insert_insn_on_edge (gen_use (const0_rtx), e);
3080 commit_edge_insertions ();
3085 /* Now add fake edges to the function exit for any non constant
3086 calls since there is no way that we can determine if they will
3089 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
3091 basic_block bb = BASIC_BLOCK (i);
3098 if (blocks && !TEST_BIT (blocks, i))
3101 for (insn = BB_END (bb); ; insn = prev_insn)
3103 prev_insn = PREV_INSN (insn);
3104 if (need_fake_edge_p (insn))
3107 rtx split_at_insn = insn;
3109 /* Don't split the block between a call and an insn that should
3110 remain in the same block as the call. */
3112 while (split_at_insn != BB_END (bb)
3113 && keep_with_call_p (NEXT_INSN (split_at_insn)))
3114 split_at_insn = NEXT_INSN (split_at_insn);
3116 /* The handling above of the final block before the epilogue
3117 should be enough to verify that there is no edge to the exit
3118 block in CFG already. Calling make_edge in such case would
3119 cause us to mark that edge as fake and remove it later. */
3121 #ifdef ENABLE_CHECKING
3122 if (split_at_insn == BB_END (bb))
3124 e = find_edge (bb, EXIT_BLOCK_PTR);
3125 gcc_assert (e == NULL);
3129 /* Note that the following may create a new basic block
3130 and renumber the existing basic blocks. */
3131 if (split_at_insn != BB_END (bb))
3133 e = split_block (bb, split_at_insn);
3138 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
3141 if (insn == BB_HEAD (bb))
3147 verify_flow_info ();
3149 return blocks_split;
3152 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
3153 the conditional branch target, SECOND_HEAD should be the fall-thru
3154 there is no need to handle this here the loop versioning code handles
3155 this. the reason for SECON_HEAD is that it is needed for condition
3156 in trees, and this should be of the same type since it is a hook. */
3158 rtl_lv_add_condition_to_bb (basic_block first_head ,
3159 basic_block second_head ATTRIBUTE_UNUSED,
3160 basic_block cond_bb, void *comp_rtx)
3162 rtx label, seq, jump;
3163 rtx op0 = XEXP ((rtx)comp_rtx, 0);
3164 rtx op1 = XEXP ((rtx)comp_rtx, 1);
3165 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
3166 enum machine_mode mode;
3169 label = block_label (first_head);
3170 mode = GET_MODE (op0);
3171 if (mode == VOIDmode)
3172 mode = GET_MODE (op1);
3175 op0 = force_operand (op0, NULL_RTX);
3176 op1 = force_operand (op1, NULL_RTX);
3177 do_compare_rtx_and_jump (op0, op1, comp, 0,
3178 mode, NULL_RTX, NULL_RTX, label, -1);
3179 jump = get_last_insn ();
3180 JUMP_LABEL (jump) = label;
3181 LABEL_NUSES (label)++;
3185 /* Add the new cond , in the new head. */
3186 emit_insn_after(seq, BB_END(cond_bb));
3190 /* Given a block B with unconditional branch at its end, get the
3191 store the return the branch edge and the fall-thru edge in
3192 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3194 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
3195 edge *fallthru_edge)
3197 edge e = EDGE_SUCC (b, 0);
3199 if (e->flags & EDGE_FALLTHRU)
3202 *branch_edge = EDGE_SUCC (b, 1);
3207 *fallthru_edge = EDGE_SUCC (b, 1);
3212 init_rtl_bb_info (basic_block bb)
3214 gcc_assert (!bb->il.rtl);
3215 bb->il.rtl = ggc_alloc_cleared_rtl_bb_info ();
3218 /* Returns true if it is possible to remove edge E by redirecting
3219 it to the destination of the other edge from E->src. */
3222 rtl_can_remove_branch_p (const_edge e)
3224 const_basic_block src = e->src;
3225 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
3226 const_rtx insn = BB_END (src), set;
3228 /* The conditions are taken from try_redirect_by_replacing_jump. */
3229 if (target == EXIT_BLOCK_PTR)
3232 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3235 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
3236 || BB_PARTITION (src) != BB_PARTITION (target))
3239 if (!onlyjump_p (insn)
3240 || tablejump_p (insn, NULL, NULL))
3243 set = single_set (insn);
3244 if (!set || side_effects_p (set))
3250 /* We do not want to declare these functions in a header file, since they
3251 should only be used through the cfghooks interface, and we do not want to
3252 move them here since it would require also moving quite a lot of related
3253 code. They are in cfglayout.c. */
3254 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
3255 extern basic_block cfg_layout_duplicate_bb (basic_block);
3258 rtl_duplicate_bb (basic_block bb)
3260 bb = cfg_layout_duplicate_bb (bb);
3265 /* Implementation of CFG manipulation for linearized RTL. */
3266 struct cfg_hooks rtl_cfg_hooks = {
3268 rtl_verify_flow_info,
3270 rtl_create_basic_block,
3271 rtl_redirect_edge_and_branch,
3272 rtl_redirect_edge_and_branch_force,
3273 rtl_can_remove_branch_p,
3276 rtl_move_block_after,
3277 rtl_can_merge_blocks, /* can_merge_blocks_p */
3281 cfg_layout_can_duplicate_bb_p,
3284 rtl_make_forwarder_block,
3285 rtl_tidy_fallthru_edge,
3286 rtl_force_nonfallthru,
3287 rtl_block_ends_with_call_p,
3288 rtl_block_ends_with_condjump_p,
3289 rtl_flow_call_edges_add,
3290 NULL, /* execute_on_growing_pred */
3291 NULL, /* execute_on_shrinking_pred */
3292 NULL, /* duplicate loop for trees */
3293 NULL, /* lv_add_condition_to_bb */
3294 NULL, /* lv_adjust_loop_header_phi*/
3295 NULL, /* extract_cond_bb_edges */
3296 NULL /* flush_pending_stmts */
3299 /* Implementation of CFG manipulation for cfg layout RTL, where
3300 basic block connected via fallthru edges does not have to be adjacent.
3301 This representation will hopefully become the default one in future
3302 version of the compiler. */
3304 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3306 rtl_verify_flow_info_1,
3308 cfg_layout_create_basic_block,
3309 cfg_layout_redirect_edge_and_branch,
3310 cfg_layout_redirect_edge_and_branch_force,
3311 rtl_can_remove_branch_p,
3312 cfg_layout_delete_block,
3313 cfg_layout_split_block,
3314 rtl_move_block_after,
3315 cfg_layout_can_merge_blocks_p,
3316 cfg_layout_merge_blocks,
3319 cfg_layout_can_duplicate_bb_p,
3320 cfg_layout_duplicate_bb,
3321 cfg_layout_split_edge,
3322 rtl_make_forwarder_block,
3323 NULL, /* tidy_fallthru_edge */
3324 rtl_force_nonfallthru,
3325 rtl_block_ends_with_call_p,
3326 rtl_block_ends_with_condjump_p,
3327 rtl_flow_call_edges_add,
3328 NULL, /* execute_on_growing_pred */
3329 NULL, /* execute_on_shrinking_pred */
3330 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3331 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3332 NULL, /* lv_adjust_loop_header_phi*/
3333 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3334 NULL /* flush_pending_stmts */