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"
53 #include "rtl-error.h"
56 #include "insn-attr.h"
57 #include "insn-config.h"
60 #include "common/common-target.h"
63 #include "tree-pass.h"
66 /* Holds the interesting leading and trailing notes for the function.
67 Only applicable if the CFG is in cfglayout mode. */
68 static GTY(()) rtx cfg_layout_function_footer;
69 static GTY(()) rtx cfg_layout_function_header;
71 static rtx skip_insns_after_block (basic_block);
72 static void record_effective_endpoints (void);
73 static rtx label_for_bb (basic_block);
74 static void fixup_reorder_chain (void);
76 void verify_insn_chain (void);
77 static void fixup_fallthru_exit_predecessor (void);
78 static int can_delete_note_p (const_rtx);
79 static int can_delete_label_p (const_rtx);
80 static basic_block rtl_split_edge (edge);
81 static bool rtl_move_block_after (basic_block, basic_block);
82 static int rtl_verify_flow_info (void);
83 static basic_block cfg_layout_split_block (basic_block, void *);
84 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
85 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
86 static void cfg_layout_delete_block (basic_block);
87 static void rtl_delete_block (basic_block);
88 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
89 static edge rtl_redirect_edge_and_branch (edge, basic_block);
90 static basic_block rtl_split_block (basic_block, void *);
91 static void rtl_dump_bb (FILE *, basic_block, int, int);
92 static int rtl_verify_flow_info_1 (void);
93 static void rtl_make_forwarder_block (edge);
95 /* Return true if NOTE is not one of the ones that must be kept paired,
96 so that we may simply delete it. */
99 can_delete_note_p (const_rtx note)
101 switch (NOTE_KIND (note))
103 case NOTE_INSN_DELETED:
104 case NOTE_INSN_BASIC_BLOCK:
105 case NOTE_INSN_EPILOGUE_BEG:
113 /* True if a given label can be deleted. */
116 can_delete_label_p (const_rtx label)
118 return (!LABEL_PRESERVE_P (label)
119 /* User declared labels must be preserved. */
120 && LABEL_NAME (label) == 0
121 && !in_expr_list_p (forced_labels, label));
124 /* Delete INSN by patching it out. */
127 delete_insn (rtx insn)
130 bool really_delete = true;
134 /* Some labels can't be directly removed from the INSN chain, as they
135 might be references via variables, constant pool etc.
136 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
137 if (! can_delete_label_p (insn))
139 const char *name = LABEL_NAME (insn);
140 basic_block bb = BLOCK_FOR_INSN (insn);
141 rtx bb_note = NEXT_INSN (insn);
143 really_delete = false;
144 PUT_CODE (insn, NOTE);
145 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
146 NOTE_DELETED_LABEL_NAME (insn) = name;
148 if (bb_note != NULL_RTX && NOTE_INSN_BASIC_BLOCK_P (bb_note)
149 && BLOCK_FOR_INSN (bb_note) == bb)
151 reorder_insns_nobb (insn, insn, bb_note);
152 BB_HEAD (bb) = bb_note;
153 if (BB_END (bb) == bb_note)
158 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
163 /* If this insn has already been deleted, something is very wrong. */
164 gcc_assert (!INSN_DELETED_P (insn));
166 INSN_DELETED_P (insn) = 1;
169 /* If deleting a jump, decrement the use count of the label. Deleting
170 the label itself should happen in the normal course of block merging. */
173 if (JUMP_LABEL (insn)
174 && LABEL_P (JUMP_LABEL (insn)))
175 LABEL_NUSES (JUMP_LABEL (insn))--;
177 /* If there are more targets, remove them too. */
179 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
180 && LABEL_P (XEXP (note, 0)))
182 LABEL_NUSES (XEXP (note, 0))--;
183 remove_note (insn, note);
187 /* Also if deleting any insn that references a label as an operand. */
188 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
189 && LABEL_P (XEXP (note, 0)))
191 LABEL_NUSES (XEXP (note, 0))--;
192 remove_note (insn, note);
195 if (JUMP_TABLE_DATA_P (insn))
197 rtx pat = PATTERN (insn);
198 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
199 int len = XVECLEN (pat, diff_vec_p);
202 for (i = 0; i < len; i++)
204 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
206 /* When deleting code in bulk (e.g. removing many unreachable
207 blocks) we can delete a label that's a target of the vector
208 before deleting the vector itself. */
210 LABEL_NUSES (label)--;
215 /* Like delete_insn but also purge dead edges from BB. */
218 delete_insn_and_edges (rtx insn)
223 && BLOCK_FOR_INSN (insn)
224 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
228 purge_dead_edges (BLOCK_FOR_INSN (insn));
231 /* Unlink a chain of insns between START and FINISH, leaving notes
232 that must be paired. If CLEAR_BB is true, we set bb field for
233 insns that cannot be removed to NULL. */
236 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
240 /* Unchain the insns one by one. It would be quicker to delete all of these
241 with a single unchaining, rather than one at a time, but we need to keep
246 prev = PREV_INSN (current);
247 if (NOTE_P (current) && !can_delete_note_p (current))
250 delete_insn (current);
252 if (clear_bb && !INSN_DELETED_P (current))
253 set_block_for_insn (current, NULL);
255 if (current == start)
261 /* Create a new basic block consisting of the instructions between HEAD and END
262 inclusive. This function is designed to allow fast BB construction - reuses
263 the note and basic block struct in BB_NOTE, if any and do not grow
264 BASIC_BLOCK chain and should be used directly only by CFG construction code.
265 END can be NULL in to create new empty basic block before HEAD. Both END
266 and HEAD can be NULL to create basic block at the end of INSN chain.
267 AFTER is the basic block we should be put after. */
270 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
275 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
278 /* If we found an existing note, thread it back onto the chain. */
286 after = PREV_INSN (head);
290 if (after != bb_note && NEXT_INSN (after) != bb_note)
291 reorder_insns_nobb (bb_note, bb_note, after);
295 /* Otherwise we must create a note and a basic block structure. */
299 init_rtl_bb_info (bb);
302 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
303 else if (LABEL_P (head) && end)
305 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
311 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
317 NOTE_BASIC_BLOCK (bb_note) = bb;
320 /* Always include the bb note in the block. */
321 if (NEXT_INSN (end) == bb_note)
326 bb->index = last_basic_block++;
327 bb->flags = BB_NEW | BB_RTL;
328 link_block (bb, after);
329 SET_BASIC_BLOCK (bb->index, bb);
330 df_bb_refs_record (bb->index, false);
331 update_bb_for_insn (bb);
332 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
334 /* Tag the block so that we know it has been used when considering
335 other basic block notes. */
341 /* Create new basic block consisting of instructions in between HEAD and END
342 and place it to the BB chain after block AFTER. END can be NULL to
343 create a new empty basic block before HEAD. Both END and HEAD can be
344 NULL to create basic block at the end of INSN chain. */
347 rtl_create_basic_block (void *headp, void *endp, basic_block after)
349 rtx head = (rtx) headp, end = (rtx) endp;
352 /* Grow the basic block array if needed. */
353 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
355 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
356 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
361 bb = create_basic_block_structure (head, end, NULL, after);
367 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
369 basic_block newbb = rtl_create_basic_block (head, end, after);
374 /* Delete the insns in a (non-live) block. We physically delete every
375 non-deleted-note insn, and update the flow graph appropriately.
377 Return nonzero if we deleted an exception handler. */
379 /* ??? Preserving all such notes strikes me as wrong. It would be nice
380 to post-process the stream to remove empty blocks, loops, ranges, etc. */
383 rtl_delete_block (basic_block b)
387 /* If the head of this block is a CODE_LABEL, then it might be the
388 label for an exception handler which can't be reached. We need
389 to remove the label from the exception_handler_label list. */
392 end = get_last_bb_insn (b);
394 /* Selectively delete the entire chain. */
396 delete_insn_chain (insn, end, true);
400 fprintf (dump_file, "deleting block %d\n", b->index);
401 df_bb_delete (b->index);
404 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
407 compute_bb_for_insn (void)
413 rtx end = BB_END (bb);
416 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
418 BLOCK_FOR_INSN (insn) = bb;
425 /* Release the basic_block_for_insn array. */
428 free_bb_for_insn (void)
431 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
432 if (!BARRIER_P (insn))
433 BLOCK_FOR_INSN (insn) = NULL;
438 rest_of_pass_free_cfg (void)
441 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
442 valid at that point so it would be too late to call df_analyze. */
443 if (optimize > 0 && flag_delayed_branch)
445 df_note_add_problem ();
454 struct rtl_opt_pass pass_free_cfg =
458 "*free_cfg", /* name */
460 rest_of_pass_free_cfg, /* execute */
463 0, /* static_pass_number */
465 0, /* properties_required */
466 0, /* properties_provided */
467 PROP_cfg, /* properties_destroyed */
468 0, /* todo_flags_start */
469 0, /* todo_flags_finish */
473 /* Return RTX to emit after when we want to emit code on the entry of function. */
475 entry_of_function (void)
477 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
478 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
481 /* Emit INSN at the entry point of the function, ensuring that it is only
482 executed once per function. */
484 emit_insn_at_entry (rtx insn)
486 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
487 edge e = ei_safe_edge (ei);
488 gcc_assert (e->flags & EDGE_FALLTHRU);
490 insert_insn_on_edge (insn, e);
491 commit_edge_insertions ();
494 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
495 (or BARRIER if found) and notify df of the bb change.
496 The insn chain range is inclusive
497 (i.e. both BEGIN and END will be updated. */
500 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
504 end = NEXT_INSN (end);
505 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
506 if (!BARRIER_P (insn))
507 df_insn_change_bb (insn, bb);
510 /* Update BLOCK_FOR_INSN of insns in BB to BB,
511 and notify df of the change. */
514 update_bb_for_insn (basic_block bb)
516 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
520 /* Like active_insn_p, except keep the return value clobber around
521 even after reload. */
524 flow_active_insn_p (const_rtx insn)
526 if (active_insn_p (insn))
529 /* A clobber of the function return value exists for buggy
530 programs that fail to return a value. Its effect is to
531 keep the return value from being live across the entire
532 function. If we allow it to be skipped, we introduce the
533 possibility for register lifetime confusion. */
534 if (GET_CODE (PATTERN (insn)) == CLOBBER
535 && REG_P (XEXP (PATTERN (insn), 0))
536 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))
542 /* Return true if the block has no effect and only forwards control flow to
543 its single destination. */
544 /* FIXME: Make this a cfg hook. */
547 forwarder_block_p (const_basic_block bb)
551 if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
552 || !single_succ_p (bb))
555 /* Protect loop latches, headers and preheaders. */
559 if (bb->loop_father->header == bb)
561 dest = EDGE_SUCC (bb, 0)->dest;
562 if (dest->loop_father->header == dest)
566 for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
567 if (INSN_P (insn) && flow_active_insn_p (insn))
570 return (!INSN_P (insn)
571 || (JUMP_P (insn) && simplejump_p (insn))
572 || !flow_active_insn_p (insn));
575 /* Return nonzero if we can reach target from src by falling through. */
576 /* FIXME: Make this a cfg hook. */
579 can_fallthru (basic_block src, basic_block target)
581 rtx insn = BB_END (src);
586 if (target == EXIT_BLOCK_PTR)
588 if (src->next_bb != target)
590 FOR_EACH_EDGE (e, ei, src->succs)
591 if (e->dest == EXIT_BLOCK_PTR
592 && e->flags & EDGE_FALLTHRU)
595 insn2 = BB_HEAD (target);
596 if (insn2 && !active_insn_p (insn2))
597 insn2 = next_active_insn (insn2);
599 /* ??? Later we may add code to move jump tables offline. */
600 return next_active_insn (insn) == insn2;
603 /* Return nonzero if we could reach target from src by falling through,
604 if the target was made adjacent. If we already have a fall-through
605 edge to the exit block, we can't do that. */
607 could_fall_through (basic_block src, basic_block target)
612 if (target == EXIT_BLOCK_PTR)
614 FOR_EACH_EDGE (e, ei, src->succs)
615 if (e->dest == EXIT_BLOCK_PTR
616 && e->flags & EDGE_FALLTHRU)
621 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
623 bb_note (basic_block bb)
629 note = NEXT_INSN (note);
631 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note));
635 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
636 note associated with the BLOCK. */
639 first_insn_after_basic_block_note (basic_block block)
643 /* Get the first instruction in the block. */
644 insn = BB_HEAD (block);
646 if (insn == NULL_RTX)
649 insn = NEXT_INSN (insn);
650 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
652 return NEXT_INSN (insn);
655 /* Creates a new basic block just after basic block B by splitting
656 everything after specified instruction I. */
659 rtl_split_block (basic_block bb, void *insnp)
662 rtx insn = (rtx) insnp;
668 insn = first_insn_after_basic_block_note (bb);
674 insn = PREV_INSN (insn);
676 /* If the block contains only debug insns, insn would have
677 been NULL in a non-debug compilation, and then we'd end
678 up emitting a DELETED note. For -fcompare-debug
679 stability, emit the note too. */
680 if (insn != BB_END (bb)
681 && DEBUG_INSN_P (next)
682 && DEBUG_INSN_P (BB_END (bb)))
684 while (next != BB_END (bb) && DEBUG_INSN_P (next))
685 next = NEXT_INSN (next);
687 if (next == BB_END (bb))
688 emit_note_after (NOTE_INSN_DELETED, next);
692 insn = get_last_insn ();
695 /* We probably should check type of the insn so that we do not create
696 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
698 if (insn == BB_END (bb))
699 emit_note_after (NOTE_INSN_DELETED, insn);
701 /* Create the new basic block. */
702 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
703 BB_COPY_PARTITION (new_bb, bb);
706 /* Redirect the outgoing edges. */
707 new_bb->succs = bb->succs;
709 FOR_EACH_EDGE (e, ei, new_bb->succs)
712 /* The new block starts off being dirty. */
713 df_set_bb_dirty (bb);
717 /* Return true if the single edge between blocks A and B is the only place
718 in RTL which holds some unique locus. */
721 unique_locus_on_edge_between_p (basic_block a, basic_block b)
723 const location_t goto_locus = EDGE_SUCC (a, 0)->goto_locus;
726 if (LOCATION_LOCUS (goto_locus) == UNKNOWN_LOCATION)
729 /* First scan block A backward. */
731 end = PREV_INSN (BB_HEAD (a));
732 while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn)))
733 insn = PREV_INSN (insn);
735 if (insn != end && INSN_LOCATION (insn) == goto_locus)
738 /* Then scan block B forward. */
742 end = NEXT_INSN (BB_END (b));
743 while (insn != end && !NONDEBUG_INSN_P (insn))
744 insn = NEXT_INSN (insn);
746 if (insn != end && INSN_HAS_LOCATION (insn)
747 && INSN_LOCATION (insn) == goto_locus)
754 /* If the single edge between blocks A and B is the only place in RTL which
755 holds some unique locus, emit a nop with that locus between the blocks. */
758 emit_nop_for_unique_locus_between (basic_block a, basic_block b)
760 if (!unique_locus_on_edge_between_p (a, b))
763 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
764 INSN_LOCATION (BB_END (a)) = EDGE_SUCC (a, 0)->goto_locus;
767 /* Blocks A and B are to be merged into a single block A. The insns
768 are already contiguous. */
771 rtl_merge_blocks (basic_block a, basic_block b)
773 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
774 rtx del_first = NULL_RTX, del_last = NULL_RTX;
775 rtx b_debug_start = b_end, b_debug_end = b_end;
776 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
780 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
783 while (DEBUG_INSN_P (b_end))
784 b_end = PREV_INSN (b_debug_start = b_end);
786 /* If there was a CODE_LABEL beginning B, delete it. */
787 if (LABEL_P (b_head))
789 /* Detect basic blocks with nothing but a label. This can happen
790 in particular at the end of a function. */
794 del_first = del_last = b_head;
795 b_head = NEXT_INSN (b_head);
798 /* Delete the basic block note and handle blocks containing just that
800 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
808 b_head = NEXT_INSN (b_head);
811 /* If there was a jump out of A, delete it. */
816 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
818 || NOTE_INSN_BASIC_BLOCK_P (prev)
819 || prev == BB_HEAD (a))
825 /* If this was a conditional jump, we need to also delete
826 the insn that set cc0. */
827 if (only_sets_cc0_p (prev))
831 prev = prev_nonnote_insn (prev);
838 a_end = PREV_INSN (del_first);
840 else if (BARRIER_P (NEXT_INSN (a_end)))
841 del_first = NEXT_INSN (a_end);
843 /* Delete everything marked above as well as crap that might be
844 hanging out between the two blocks. */
846 BB_HEAD (b) = b_empty ? NULL_RTX : b_head;
847 delete_insn_chain (del_first, del_last, true);
849 /* When not optimizing CFG and the edge is the only place in RTL which holds
850 some unique locus, emit a nop with that locus in between. */
853 emit_nop_for_unique_locus_between (a, b);
857 /* Reassociate the insns of B with A. */
860 update_bb_for_insn_chain (a_end, b_debug_end, a);
862 BB_END (a) = b_debug_end;
863 BB_HEAD (b) = NULL_RTX;
865 else if (b_end != b_debug_end)
867 /* Move any deleted labels and other notes between the end of A
868 and the debug insns that make up B after the debug insns,
869 bringing the debug insns into A while keeping the notes after
871 if (NEXT_INSN (a_end) != b_debug_start)
872 reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
874 update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
875 BB_END (a) = b_debug_end;
878 df_bb_delete (b->index);
880 /* If B was a forwarder block, propagate the locus on the edge. */
881 if (forwarder_p && !EDGE_SUCC (b, 0)->goto_locus)
882 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
885 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
889 /* Return true when block A and B can be merged. */
892 rtl_can_merge_blocks (basic_block a, basic_block b)
894 /* If we are partitioning hot/cold basic blocks, we don't want to
895 mess up unconditional or indirect jumps that cross between hot
898 Basic block partitioning may result in some jumps that appear to
899 be optimizable (or blocks that appear to be mergeable), but which really
900 must be left untouched (they are required to make it safely across
901 partition boundaries). See the comments at the top of
902 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
904 if (BB_PARTITION (a) != BB_PARTITION (b))
907 /* Protect the loop latches. */
908 if (current_loops && b->loop_father->latch == b)
911 /* There must be exactly one edge in between the blocks. */
912 return (single_succ_p (a)
913 && single_succ (a) == b
916 /* Must be simple edge. */
917 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
919 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
920 /* If the jump insn has side effects,
921 we can't kill the edge. */
922 && (!JUMP_P (BB_END (a))
924 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
927 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
931 block_label (basic_block block)
933 if (block == EXIT_BLOCK_PTR)
936 if (!LABEL_P (BB_HEAD (block)))
938 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
941 return BB_HEAD (block);
944 /* Attempt to perform edge redirection by replacing possibly complex jump
945 instruction by unconditional jump or removing jump completely. This can
946 apply only if all edges now point to the same block. The parameters and
947 return values are equivalent to redirect_edge_and_branch. */
950 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
952 basic_block src = e->src;
953 rtx insn = BB_END (src), kill_from;
957 /* If we are partitioning hot/cold basic blocks, we don't want to
958 mess up unconditional or indirect jumps that cross between hot
961 Basic block partitioning may result in some jumps that appear to
962 be optimizable (or blocks that appear to be mergeable), but which really
963 must be left untouched (they are required to make it safely across
964 partition boundaries). See the comments at the top of
965 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
967 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
968 || BB_PARTITION (src) != BB_PARTITION (target))
971 /* We can replace or remove a complex jump only when we have exactly
972 two edges. Also, if we have exactly one outgoing edge, we can
974 if (EDGE_COUNT (src->succs) >= 3
975 /* Verify that all targets will be TARGET. Specifically, the
976 edge that is not E must also go to TARGET. */
977 || (EDGE_COUNT (src->succs) == 2
978 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
981 if (!onlyjump_p (insn))
983 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
986 /* Avoid removing branch with side effects. */
987 set = single_set (insn);
988 if (!set || side_effects_p (set))
991 /* In case we zap a conditional jump, we'll need to kill
992 the cc0 setter too. */
995 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
996 && only_sets_cc0_p (PREV_INSN (insn)))
997 kill_from = PREV_INSN (insn);
1000 /* See if we can create the fallthru edge. */
1001 if (in_cfglayout || can_fallthru (src, target))
1004 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
1007 /* Selectively unlink whole insn chain. */
1010 rtx insn = BB_FOOTER (src);
1012 delete_insn_chain (kill_from, BB_END (src), false);
1014 /* Remove barriers but keep jumptables. */
1017 if (BARRIER_P (insn))
1019 if (PREV_INSN (insn))
1020 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
1022 BB_FOOTER (src) = NEXT_INSN (insn);
1023 if (NEXT_INSN (insn))
1024 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
1028 insn = NEXT_INSN (insn);
1032 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
1036 /* If this already is simplejump, redirect it. */
1037 else if (simplejump_p (insn))
1039 if (e->dest == target)
1042 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
1043 INSN_UID (insn), e->dest->index, target->index);
1044 if (!redirect_jump (insn, block_label (target), 0))
1046 gcc_assert (target == EXIT_BLOCK_PTR);
1051 /* Cannot do anything for target exit block. */
1052 else if (target == EXIT_BLOCK_PTR)
1055 /* Or replace possibly complicated jump insn by simple jump insn. */
1058 rtx target_label = block_label (target);
1059 rtx barrier, label, table;
1061 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
1062 JUMP_LABEL (BB_END (src)) = target_label;
1063 LABEL_NUSES (target_label)++;
1065 fprintf (dump_file, "Replacing insn %i by jump %i\n",
1066 INSN_UID (insn), INSN_UID (BB_END (src)));
1069 delete_insn_chain (kill_from, insn, false);
1071 /* Recognize a tablejump that we are converting to a
1072 simple jump and remove its associated CODE_LABEL
1073 and ADDR_VEC or ADDR_DIFF_VEC. */
1074 if (tablejump_p (insn, &label, &table))
1075 delete_insn_chain (label, table, false);
1077 barrier = next_nonnote_insn (BB_END (src));
1078 if (!barrier || !BARRIER_P (barrier))
1079 emit_barrier_after (BB_END (src));
1082 if (barrier != NEXT_INSN (BB_END (src)))
1084 /* Move the jump before barrier so that the notes
1085 which originally were or were created before jump table are
1086 inside the basic block. */
1087 rtx new_insn = BB_END (src);
1089 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
1090 PREV_INSN (barrier), src);
1092 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
1093 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
1095 NEXT_INSN (new_insn) = barrier;
1096 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
1098 PREV_INSN (new_insn) = PREV_INSN (barrier);
1099 PREV_INSN (barrier) = new_insn;
1104 /* Keep only one edge out and set proper flags. */
1105 if (!single_succ_p (src))
1107 gcc_assert (single_succ_p (src));
1109 e = single_succ_edge (src);
1111 e->flags = EDGE_FALLTHRU;
1115 e->probability = REG_BR_PROB_BASE;
1116 e->count = src->count;
1118 if (e->dest != target)
1119 redirect_edge_succ (e, target);
1123 /* Subroutine of redirect_branch_edge that tries to patch the jump
1124 instruction INSN so that it reaches block NEW. Do this
1125 only when it originally reached block OLD. Return true if this
1126 worked or the original target wasn't OLD, return false if redirection
1130 patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
1133 /* Recognize a tablejump and adjust all matching cases. */
1134 if (tablejump_p (insn, NULL, &tmp))
1138 rtx new_label = block_label (new_bb);
1140 if (new_bb == EXIT_BLOCK_PTR)
1142 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1143 vec = XVEC (PATTERN (tmp), 0);
1145 vec = XVEC (PATTERN (tmp), 1);
1147 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1148 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1150 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
1151 --LABEL_NUSES (old_label);
1152 ++LABEL_NUSES (new_label);
1155 /* Handle casesi dispatch insns. */
1156 if ((tmp = single_set (insn)) != NULL
1157 && SET_DEST (tmp) == pc_rtx
1158 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1159 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1160 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1162 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
1164 --LABEL_NUSES (old_label);
1165 ++LABEL_NUSES (new_label);
1168 else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
1170 int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
1171 rtx new_label, note;
1173 if (new_bb == EXIT_BLOCK_PTR)
1175 new_label = block_label (new_bb);
1177 for (i = 0; i < n; ++i)
1179 rtx old_ref = ASM_OPERANDS_LABEL (tmp, i);
1180 gcc_assert (GET_CODE (old_ref) == LABEL_REF);
1181 if (XEXP (old_ref, 0) == old_label)
1183 ASM_OPERANDS_LABEL (tmp, i)
1184 = gen_rtx_LABEL_REF (Pmode, new_label);
1185 --LABEL_NUSES (old_label);
1186 ++LABEL_NUSES (new_label);
1190 if (JUMP_LABEL (insn) == old_label)
1192 JUMP_LABEL (insn) = new_label;
1193 note = find_reg_note (insn, REG_LABEL_TARGET, new_label);
1195 remove_note (insn, note);
1199 note = find_reg_note (insn, REG_LABEL_TARGET, old_label);
1201 remove_note (insn, note);
1202 if (JUMP_LABEL (insn) != new_label
1203 && !find_reg_note (insn, REG_LABEL_TARGET, new_label))
1204 add_reg_note (insn, REG_LABEL_TARGET, new_label);
1206 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
1208 XEXP (note, 0) = new_label;
1212 /* ?? We may play the games with moving the named labels from
1213 one basic block to the other in case only one computed_jump is
1215 if (computed_jump_p (insn)
1216 /* A return instruction can't be redirected. */
1217 || returnjump_p (insn))
1220 if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
1222 /* If the insn doesn't go where we think, we're confused. */
1223 gcc_assert (JUMP_LABEL (insn) == old_label);
1225 /* If the substitution doesn't succeed, die. This can happen
1226 if the back end emitted unrecognizable instructions or if
1227 target is exit block on some arches. */
1228 if (!redirect_jump (insn, block_label (new_bb), 0))
1230 gcc_assert (new_bb == EXIT_BLOCK_PTR);
1239 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1242 redirect_branch_edge (edge e, basic_block target)
1244 rtx old_label = BB_HEAD (e->dest);
1245 basic_block src = e->src;
1246 rtx insn = BB_END (src);
1248 /* We can only redirect non-fallthru edges of jump insn. */
1249 if (e->flags & EDGE_FALLTHRU)
1251 else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
1254 if (!currently_expanding_to_rtl)
1256 if (!patch_jump_insn (insn, old_label, target))
1260 /* When expanding this BB might actually contain multiple
1261 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1262 Redirect all of those that match our label. */
1263 FOR_BB_INSNS (src, insn)
1264 if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target))
1268 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
1269 e->src->index, e->dest->index, target->index);
1271 if (e->dest != target)
1272 e = redirect_edge_succ_nodup (e, target);
1277 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1278 expense of adding new instructions or reordering basic blocks.
1280 Function can be also called with edge destination equivalent to the TARGET.
1281 Then it should try the simplifications and do nothing if none is possible.
1283 Return edge representing the branch if transformation succeeded. Return NULL
1285 We still return NULL in case E already destinated TARGET and we didn't
1286 managed to simplify instruction stream. */
1289 rtl_redirect_edge_and_branch (edge e, basic_block target)
1292 basic_block src = e->src;
1294 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1297 if (e->dest == target)
1300 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
1302 df_set_bb_dirty (src);
1306 ret = redirect_branch_edge (e, target);
1310 df_set_bb_dirty (src);
1314 /* Like force_nonfallthru below, but additionally performs redirection
1315 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1316 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1317 simple_return_rtx, indicating which kind of returnjump to create.
1318 It should be NULL otherwise. */
1321 force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label)
1323 basic_block jump_block, new_bb = NULL, src = e->src;
1326 int abnormal_edge_flags = 0;
1327 bool asm_goto_edge = false;
1330 /* In the case the last instruction is conditional jump to the next
1331 instruction, first redirect the jump itself and then continue
1332 by creating a basic block afterwards to redirect fallthru edge. */
1333 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1334 && any_condjump_p (BB_END (e->src))
1335 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1338 edge b = unchecked_make_edge (e->src, target, 0);
1341 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1342 gcc_assert (redirected);
1344 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1347 int prob = INTVAL (XEXP (note, 0));
1349 b->probability = prob;
1350 b->count = e->count * prob / REG_BR_PROB_BASE;
1351 e->probability -= e->probability;
1352 e->count -= b->count;
1353 if (e->probability < 0)
1360 if (e->flags & EDGE_ABNORMAL)
1362 /* Irritating special case - fallthru edge to the same block as abnormal
1364 We can't redirect abnormal edge, but we still can split the fallthru
1365 one and create separate abnormal edge to original destination.
1366 This allows bb-reorder to make such edge non-fallthru. */
1367 gcc_assert (e->dest == target);
1368 abnormal_edge_flags = e->flags & ~EDGE_FALLTHRU;
1369 e->flags &= EDGE_FALLTHRU;
1373 gcc_assert (e->flags & EDGE_FALLTHRU);
1374 if (e->src == ENTRY_BLOCK_PTR)
1376 /* We can't redirect the entry block. Create an empty block
1377 at the start of the function which we use to add the new
1383 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1385 /* Change the existing edge's source to be the new block, and add
1386 a new edge from the entry block to the new block. */
1388 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1392 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1402 VEC_safe_push (edge, gc, bb->succs, e);
1403 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1407 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1408 don't point to the target or fallthru label. */
1409 if (JUMP_P (BB_END (e->src))
1410 && target != EXIT_BLOCK_PTR
1411 && (e->flags & EDGE_FALLTHRU)
1412 && (note = extract_asm_operands (PATTERN (BB_END (e->src)))))
1414 int i, n = ASM_OPERANDS_LABEL_LENGTH (note);
1416 for (i = 0; i < n; ++i)
1418 if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (e->dest))
1419 XEXP (ASM_OPERANDS_LABEL (note, i), 0) = block_label (target);
1420 if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target))
1421 asm_goto_edge = true;
1425 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge)
1427 gcov_type count = e->count;
1428 int probability = e->probability;
1429 /* Create the new structures. */
1431 /* If the old block ended with a tablejump, skip its table
1432 by searching forward from there. Otherwise start searching
1433 forward from the last instruction of the old block. */
1434 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1435 note = BB_END (e->src);
1436 note = NEXT_INSN (note);
1438 jump_block = create_basic_block (note, NULL, e->src);
1439 jump_block->count = count;
1440 jump_block->frequency = EDGE_FREQUENCY (e);
1442 /* Make sure new block ends up in correct hot/cold section. */
1444 BB_COPY_PARTITION (jump_block, e->src);
1445 if (flag_reorder_blocks_and_partition
1446 && targetm_common.have_named_sections
1447 && JUMP_P (BB_END (jump_block))
1448 && !any_condjump_p (BB_END (jump_block))
1449 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1450 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1453 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1454 new_edge->probability = probability;
1455 new_edge->count = count;
1457 /* Redirect old edge. */
1458 redirect_edge_pred (e, jump_block);
1459 e->probability = REG_BR_PROB_BASE;
1461 /* If asm goto has any label refs to target's label,
1462 add also edge from asm goto bb to target. */
1465 new_edge->probability /= 2;
1466 new_edge->count /= 2;
1467 jump_block->count /= 2;
1468 jump_block->frequency /= 2;
1469 new_edge = make_edge (new_edge->src, target,
1470 e->flags & ~EDGE_FALLTHRU);
1471 new_edge->probability = probability - probability / 2;
1472 new_edge->count = count - count / 2;
1475 new_bb = jump_block;
1478 jump_block = e->src;
1480 loc = e->goto_locus;
1481 e->flags &= ~EDGE_FALLTHRU;
1482 if (target == EXIT_BLOCK_PTR)
1484 if (jump_label == ret_rtx)
1487 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1494 gcc_assert (jump_label == simple_return_rtx);
1495 #ifdef HAVE_simple_return
1496 emit_jump_insn_after_setloc (gen_simple_return (),
1497 BB_END (jump_block), loc);
1502 set_return_jump_label (BB_END (jump_block));
1506 rtx label = block_label (target);
1507 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1508 JUMP_LABEL (BB_END (jump_block)) = label;
1509 LABEL_NUSES (label)++;
1512 emit_barrier_after (BB_END (jump_block));
1513 redirect_edge_succ_nodup (e, target);
1515 if (abnormal_edge_flags)
1516 make_edge (src, target, abnormal_edge_flags);
1518 df_mark_solutions_dirty ();
1522 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1523 (and possibly create new basic block) to make edge non-fallthru.
1524 Return newly created BB or NULL if none. */
1527 rtl_force_nonfallthru (edge e)
1529 return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX);
1532 /* Redirect edge even at the expense of creating new jump insn or
1533 basic block. Return new basic block if created, NULL otherwise.
1534 Conversion must be possible. */
1537 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1539 if (redirect_edge_and_branch (e, target)
1540 || e->dest == target)
1543 /* In case the edge redirection failed, try to force it to be non-fallthru
1544 and redirect newly created simplejump. */
1545 df_set_bb_dirty (e->src);
1546 return force_nonfallthru_and_redirect (e, target, NULL_RTX);
1549 /* The given edge should potentially be a fallthru edge. If that is in
1550 fact true, delete the jump and barriers that are in the way. */
1553 rtl_tidy_fallthru_edge (edge e)
1556 basic_block b = e->src, c = b->next_bb;
1558 /* ??? In a late-running flow pass, other folks may have deleted basic
1559 blocks by nopping out blocks, leaving multiple BARRIERs between here
1560 and the target label. They ought to be chastised and fixed.
1562 We can also wind up with a sequence of undeletable labels between
1563 one block and the next.
1565 So search through a sequence of barriers, labels, and notes for
1566 the head of block C and assert that we really do fall through. */
1568 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1572 /* Remove what will soon cease being the jump insn from the source block.
1573 If block B consisted only of this single jump, turn it into a deleted
1578 && (any_uncondjump_p (q)
1579 || single_succ_p (b)))
1582 /* If this was a conditional jump, we need to also delete
1583 the insn that set cc0. */
1584 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1591 /* Selectively unlink the sequence. */
1592 if (q != PREV_INSN (BB_HEAD (c)))
1593 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1595 e->flags |= EDGE_FALLTHRU;
1598 /* Should move basic block BB after basic block AFTER. NIY. */
1601 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1602 basic_block after ATTRIBUTE_UNUSED)
1607 /* Split a (typically critical) edge. Return the new block.
1608 The edge must not be abnormal.
1610 ??? The code generally expects to be called on critical edges.
1611 The case of a block ending in an unconditional jump to a
1612 block with multiple predecessors is not handled optimally. */
1615 rtl_split_edge (edge edge_in)
1620 /* Abnormal edges cannot be split. */
1621 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1623 /* We are going to place the new block in front of edge destination.
1624 Avoid existence of fallthru predecessors. */
1625 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1627 edge e = find_fallthru_edge (edge_in->dest->preds);
1630 force_nonfallthru (e);
1633 /* Create the basic block note. */
1634 if (edge_in->dest != EXIT_BLOCK_PTR)
1635 before = BB_HEAD (edge_in->dest);
1639 /* If this is a fall through edge to the exit block, the blocks might be
1640 not adjacent, and the right place is after the source. */
1641 if ((edge_in->flags & EDGE_FALLTHRU) && edge_in->dest == EXIT_BLOCK_PTR)
1643 before = NEXT_INSN (BB_END (edge_in->src));
1644 bb = create_basic_block (before, NULL, edge_in->src);
1645 BB_COPY_PARTITION (bb, edge_in->src);
1649 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1650 /* ??? Why not edge_in->dest->prev_bb here? */
1651 BB_COPY_PARTITION (bb, edge_in->dest);
1654 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1656 /* For non-fallthru edges, we must adjust the predecessor's
1657 jump instruction to target our new block. */
1658 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1660 edge redirected = redirect_edge_and_branch (edge_in, bb);
1661 gcc_assert (redirected);
1665 if (edge_in->src != ENTRY_BLOCK_PTR)
1667 /* For asm goto even splitting of fallthru edge might
1668 need insn patching, as other labels might point to the
1670 rtx last = BB_END (edge_in->src);
1673 && edge_in->dest != EXIT_BLOCK_PTR
1674 && extract_asm_operands (PATTERN (last)) != NULL_RTX
1675 && patch_jump_insn (last, before, bb))
1676 df_set_bb_dirty (edge_in->src);
1678 redirect_edge_succ (edge_in, bb);
1684 /* Queue instructions for insertion on an edge between two basic blocks.
1685 The new instructions and basic blocks (if any) will not appear in the
1686 CFG until commit_edge_insertions is called. */
1689 insert_insn_on_edge (rtx pattern, edge e)
1691 /* We cannot insert instructions on an abnormal critical edge.
1692 It will be easier to find the culprit if we die now. */
1693 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1695 if (e->insns.r == NULL_RTX)
1698 push_to_sequence (e->insns.r);
1700 emit_insn (pattern);
1702 e->insns.r = get_insns ();
1706 /* Update the CFG for the instructions queued on edge E. */
1709 commit_one_edge_insertion (edge e)
1711 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1714 /* Pull the insns off the edge now since the edge might go away. */
1716 e->insns.r = NULL_RTX;
1718 /* Figure out where to put these insns. If the destination has
1719 one predecessor, insert there. Except for the exit block. */
1720 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1724 /* Get the location correct wrt a code label, and "nice" wrt
1725 a basic block note, and before everything else. */
1728 tmp = NEXT_INSN (tmp);
1729 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1730 tmp = NEXT_INSN (tmp);
1731 if (tmp == BB_HEAD (bb))
1734 after = PREV_INSN (tmp);
1736 after = get_last_insn ();
1739 /* If the source has one successor and the edge is not abnormal,
1740 insert there. Except for the entry block. */
1741 else if ((e->flags & EDGE_ABNORMAL) == 0
1742 && single_succ_p (e->src)
1743 && e->src != ENTRY_BLOCK_PTR)
1747 /* It is possible to have a non-simple jump here. Consider a target
1748 where some forms of unconditional jumps clobber a register. This
1749 happens on the fr30 for example.
1751 We know this block has a single successor, so we can just emit
1752 the queued insns before the jump. */
1753 if (JUMP_P (BB_END (bb)))
1754 before = BB_END (bb);
1757 /* We'd better be fallthru, or we've lost track of what's what. */
1758 gcc_assert (e->flags & EDGE_FALLTHRU);
1760 after = BB_END (bb);
1764 /* Otherwise we must split the edge. */
1767 bb = split_edge (e);
1768 after = BB_END (bb);
1770 if (flag_reorder_blocks_and_partition
1771 && targetm_common.have_named_sections
1772 && e->src != ENTRY_BLOCK_PTR
1773 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1774 && !(e->flags & EDGE_CROSSING)
1776 && !any_condjump_p (after)
1777 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1778 add_reg_note (after, REG_CROSSING_JUMP, NULL_RTX);
1781 /* Now that we've found the spot, do the insertion. */
1784 emit_insn_before_noloc (insns, before, bb);
1785 last = prev_nonnote_insn (before);
1788 last = emit_insn_after_noloc (insns, after, bb);
1790 if (returnjump_p (last))
1792 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1793 This is not currently a problem because this only happens
1794 for the (single) epilogue, which already has a fallthru edge
1797 e = single_succ_edge (bb);
1798 gcc_assert (e->dest == EXIT_BLOCK_PTR
1799 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1801 e->flags &= ~EDGE_FALLTHRU;
1802 emit_barrier_after (last);
1805 delete_insn (before);
1808 gcc_assert (!JUMP_P (last));
1811 /* Update the CFG for all queued instructions. */
1814 commit_edge_insertions (void)
1818 #ifdef ENABLE_CHECKING
1819 verify_flow_info ();
1822 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1827 FOR_EACH_EDGE (e, ei, bb->succs)
1829 commit_one_edge_insertion (e);
1834 /* Print out RTL-specific basic block information (live information
1835 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
1836 documented in dumpfile.h. */
1839 rtl_dump_bb (FILE *outf, basic_block bb, int indent, int flags)
1845 s_indent = (char *) alloca ((size_t) indent + 1);
1846 memset (s_indent, ' ', (size_t) indent);
1847 s_indent[indent] = '\0';
1849 if (df && (flags & TDF_DETAILS))
1851 df_dump_top (bb, outf);
1855 if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK)
1856 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1857 insn = NEXT_INSN (insn))
1859 if (flags & TDF_DETAILS)
1860 df_dump_insn_top (insn, outf);
1861 if (! (flags & TDF_SLIM))
1862 print_rtl_single (outf, insn);
1864 dump_insn_slim (outf, insn);
1865 if (flags & TDF_DETAILS)
1866 df_dump_insn_bottom (insn, outf);
1869 if (df && (flags & TDF_DETAILS))
1871 df_dump_bottom (bb, outf);
1877 /* Like dump_function_to_file, but for RTL. Print out dataflow information
1878 for the start of each basic block. FLAGS are the TDF_* masks documented
1882 print_rtl_with_bb (FILE *outf, const_rtx rtx_first, int flags)
1886 fprintf (outf, "(nil)\n");
1889 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1890 int max_uid = get_max_uid ();
1891 basic_block *start = XCNEWVEC (basic_block, max_uid);
1892 basic_block *end = XCNEWVEC (basic_block, max_uid);
1893 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1896 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
1897 insns, but the CFG is not maintained so the basic block info
1898 is not reliable. Therefore it's omitted from the dumps. */
1899 if (! (cfun->curr_properties & PROP_cfg))
1900 flags &= ~TDF_BLOCKS;
1903 df_dump_start (outf);
1905 if (flags & TDF_BLOCKS)
1907 FOR_EACH_BB_REVERSE (bb)
1911 start[INSN_UID (BB_HEAD (bb))] = bb;
1912 end[INSN_UID (BB_END (bb))] = bb;
1913 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1915 enum bb_state state = IN_MULTIPLE_BB;
1917 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1919 in_bb_p[INSN_UID (x)] = state;
1921 if (x == BB_END (bb))
1927 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1929 if (flags & TDF_BLOCKS)
1931 bb = start[INSN_UID (tmp_rtx)];
1934 dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, true, false);
1935 if (df && (flags & TDF_DETAILS))
1936 df_dump_top (bb, outf);
1939 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1940 && !NOTE_P (tmp_rtx)
1941 && !BARRIER_P (tmp_rtx))
1942 fprintf (outf, ";; Insn is not within a basic block\n");
1943 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1944 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1947 if (flags & TDF_DETAILS)
1948 df_dump_insn_top (tmp_rtx, outf);
1949 if (! (flags & TDF_SLIM))
1950 print_rtl_single (outf, tmp_rtx);
1952 dump_insn_slim (outf, tmp_rtx);
1953 if (flags & TDF_DETAILS)
1954 df_dump_insn_bottom (tmp_rtx, outf);
1956 if (flags & TDF_BLOCKS)
1958 bb = end[INSN_UID (tmp_rtx)];
1961 dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, false, true);
1962 if (df && (flags & TDF_DETAILS))
1963 df_dump_bottom (bb, outf);
1974 if (crtl->epilogue_delay_list != 0)
1976 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1977 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1978 tmp_rtx = XEXP (tmp_rtx, 1))
1979 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1983 /* Update the branch probability of BB if a REG_BR_PROB is present. */
1986 update_br_prob_note (basic_block bb)
1989 if (!JUMP_P (BB_END (bb)))
1991 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1992 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1994 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1997 /* Get the last insn associated with block BB (that includes barriers and
1998 tablejumps after BB). */
2000 get_last_bb_insn (basic_block bb)
2003 rtx end = BB_END (bb);
2005 /* Include any jump table following the basic block. */
2006 if (tablejump_p (end, NULL, &tmp))
2009 /* Include any barriers that may follow the basic block. */
2010 tmp = next_nonnote_insn_bb (end);
2011 while (tmp && BARRIER_P (tmp))
2014 tmp = next_nonnote_insn_bb (end);
2020 /* Verify the CFG and RTL consistency common for both underlying RTL and
2023 Currently it does following checks:
2025 - overlapping of basic blocks
2026 - insns with wrong BLOCK_FOR_INSN pointers
2027 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2028 - tails of basic blocks (ensure that boundary is necessary)
2029 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2030 and NOTE_INSN_BASIC_BLOCK
2031 - verify that no fall_thru edge crosses hot/cold partition boundaries
2032 - verify that there are no pending RTL branch predictions
2034 In future it can be extended check a lot of other stuff as well
2035 (reachability of basic blocks, life information, etc. etc.). */
2038 rtl_verify_flow_info_1 (void)
2044 /* Check the general integrity of the basic blocks. */
2045 FOR_EACH_BB_REVERSE (bb)
2049 if (!(bb->flags & BB_RTL))
2051 error ("BB_RTL flag not set for block %d", bb->index);
2055 FOR_BB_INSNS (bb, insn)
2056 if (BLOCK_FOR_INSN (insn) != bb)
2058 error ("insn %d basic block pointer is %d, should be %d",
2060 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
2065 for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn))
2066 if (!BARRIER_P (insn)
2067 && BLOCK_FOR_INSN (insn) != NULL)
2069 error ("insn %d in header of bb %d has non-NULL basic block",
2070 INSN_UID (insn), bb->index);
2073 for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn))
2074 if (!BARRIER_P (insn)
2075 && BLOCK_FOR_INSN (insn) != NULL)
2077 error ("insn %d in footer of bb %d has non-NULL basic block",
2078 INSN_UID (insn), bb->index);
2083 /* Now check the basic blocks (boundaries etc.) */
2084 FOR_EACH_BB_REVERSE (bb)
2086 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
2087 edge e, fallthru = NULL;
2091 if (JUMP_P (BB_END (bb))
2092 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
2093 && EDGE_COUNT (bb->succs) >= 2
2094 && any_condjump_p (BB_END (bb)))
2096 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
2097 && profile_status != PROFILE_ABSENT)
2099 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
2100 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
2104 FOR_EACH_EDGE (e, ei, bb->succs)
2108 if (e->flags & EDGE_FALLTHRU)
2109 n_fallthru++, fallthru = e;
2111 is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
2112 && e->src != ENTRY_BLOCK_PTR
2113 && e->dest != EXIT_BLOCK_PTR);
2114 if (e->flags & EDGE_CROSSING)
2118 error ("EDGE_CROSSING incorrectly set across same section");
2121 if (e->flags & EDGE_FALLTHRU)
2123 error ("fallthru edge crosses section boundary (bb %i)",
2127 if (e->flags & EDGE_EH)
2129 error ("EH edge crosses section boundary (bb %i)",
2134 else if (is_crossing)
2136 error ("EDGE_CROSSING missing across section boundary");
2140 if ((e->flags & ~(EDGE_DFS_BACK
2142 | EDGE_IRREDUCIBLE_LOOP
2145 | EDGE_PRESERVE)) == 0)
2148 if (e->flags & EDGE_ABNORMAL_CALL)
2151 if (e->flags & EDGE_EH)
2153 else if (e->flags & EDGE_ABNORMAL)
2157 if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
2159 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
2164 error ("too many eh edges %i", bb->index);
2168 && (!JUMP_P (BB_END (bb))
2169 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
2170 || any_condjump_p (BB_END (bb))))))
2172 error ("too many outgoing branch edges from bb %i", bb->index);
2175 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
2177 error ("fallthru edge after unconditional jump %i", bb->index);
2180 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
2182 error ("wrong number of branch edges after unconditional jump %i",
2186 if (n_branch != 1 && any_condjump_p (BB_END (bb))
2187 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
2189 error ("wrong amount of branch edges after conditional jump %i",
2193 if (n_call && !CALL_P (BB_END (bb)))
2195 error ("call edges for non-call insn in bb %i", bb->index);
2199 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
2200 && (!JUMP_P (BB_END (bb))
2201 || any_condjump_p (BB_END (bb))
2202 || any_uncondjump_p (BB_END (bb))))
2204 error ("abnormal edges for no purpose in bb %i", bb->index);
2208 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
2209 /* We may have a barrier inside a basic block before dead code
2210 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2211 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
2214 if (! BLOCK_FOR_INSN (x))
2216 ("insn %d inside basic block %d but block_for_insn is NULL",
2217 INSN_UID (x), bb->index);
2220 ("insn %d inside basic block %d but block_for_insn is %i",
2221 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
2226 /* OK pointers are correct. Now check the header of basic
2227 block. It ought to contain optional CODE_LABEL followed
2228 by NOTE_BASIC_BLOCK. */
2232 if (BB_END (bb) == x)
2234 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2242 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
2244 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2249 if (BB_END (bb) == x)
2250 /* Do checks for empty blocks here. */
2253 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
2255 if (NOTE_INSN_BASIC_BLOCK_P (x))
2257 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2258 INSN_UID (x), bb->index);
2262 if (x == BB_END (bb))
2265 if (control_flow_insn_p (x))
2267 error ("in basic block %d:", bb->index);
2268 fatal_insn ("flow control insn inside a basic block", x);
2277 /* Verify the CFG and RTL consistency common for both underlying RTL and
2280 Currently it does following checks:
2281 - all checks of rtl_verify_flow_info_1
2282 - test head/end pointers
2283 - check that all insns are in the basic blocks
2284 (except the switch handling code, barriers and notes)
2285 - check that all returns are followed by barriers
2286 - check that all fallthru edge points to the adjacent blocks. */
2289 rtl_verify_flow_info (void)
2292 int err = rtl_verify_flow_info_1 ();
2294 rtx last_head = get_last_insn ();
2295 basic_block *bb_info;
2297 const rtx rtx_first = get_insns ();
2298 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2299 const int max_uid = get_max_uid ();
2301 bb_info = XCNEWVEC (basic_block, max_uid);
2303 FOR_EACH_BB_REVERSE (bb)
2306 rtx head = BB_HEAD (bb);
2307 rtx end = BB_END (bb);
2309 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2311 /* Verify the end of the basic block is in the INSN chain. */
2315 /* And that the code outside of basic blocks has NULL bb field. */
2317 && BLOCK_FOR_INSN (x) != NULL)
2319 error ("insn %d outside of basic blocks has non-NULL bb field",
2327 error ("end insn %d for block %d not found in the insn stream",
2328 INSN_UID (end), bb->index);
2332 /* Work backwards from the end to the head of the basic block
2333 to verify the head is in the RTL chain. */
2334 for (; x != NULL_RTX; x = PREV_INSN (x))
2336 /* While walking over the insn chain, verify insns appear
2337 in only one basic block. */
2338 if (bb_info[INSN_UID (x)] != NULL)
2340 error ("insn %d is in multiple basic blocks (%d and %d)",
2341 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2345 bb_info[INSN_UID (x)] = bb;
2352 error ("head insn %d for block %d not found in the insn stream",
2353 INSN_UID (head), bb->index);
2357 last_head = PREV_INSN (x);
2359 e = find_fallthru_edge (bb->succs);
2364 /* Ensure existence of barrier in BB with no fallthru edges. */
2365 for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn))
2367 if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn))
2369 error ("missing barrier after block %i", bb->index);
2373 if (BARRIER_P (insn))
2377 else if (e->src != ENTRY_BLOCK_PTR
2378 && e->dest != EXIT_BLOCK_PTR)
2382 if (e->src->next_bb != e->dest)
2385 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2386 e->src->index, e->dest->index);
2390 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2391 insn = NEXT_INSN (insn))
2392 if (BARRIER_P (insn) || INSN_P (insn))
2394 error ("verify_flow_info: Incorrect fallthru %i->%i",
2395 e->src->index, e->dest->index);
2396 fatal_insn ("wrong insn in the fallthru edge", insn);
2402 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2404 /* Check that the code before the first basic block has NULL
2407 && BLOCK_FOR_INSN (x) != NULL)
2409 error ("insn %d outside of basic blocks has non-NULL bb field",
2417 last_bb_seen = ENTRY_BLOCK_PTR;
2419 for (x = rtx_first; x; x = NEXT_INSN (x))
2421 if (NOTE_INSN_BASIC_BLOCK_P (x))
2423 bb = NOTE_BASIC_BLOCK (x);
2426 if (bb != last_bb_seen->next_bb)
2427 internal_error ("basic blocks not laid down consecutively");
2429 curr_bb = last_bb_seen = bb;
2434 switch (GET_CODE (x))
2441 /* An addr_vec is placed outside any basic block. */
2443 && JUMP_TABLE_DATA_P (NEXT_INSN (x)))
2446 /* But in any case, non-deletable labels can appear anywhere. */
2450 fatal_insn ("insn outside basic block", x);
2455 && returnjump_p (x) && ! condjump_p (x)
2456 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2457 fatal_insn ("return not followed by barrier", x);
2458 if (curr_bb && x == BB_END (curr_bb))
2462 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2464 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2465 num_bb_notes, n_basic_blocks);
2470 /* Assume that the preceding pass has possibly eliminated jump instructions
2471 or converted the unconditional jumps. Eliminate the edges from CFG.
2472 Return true if any edges are eliminated. */
2475 purge_dead_edges (basic_block bb)
2478 rtx insn = BB_END (bb), note;
2479 bool purged = false;
2483 if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb))
2485 insn = PREV_INSN (insn);
2486 while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
2488 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2489 if (NONJUMP_INSN_P (insn)
2490 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2494 if (! may_trap_p (PATTERN (insn))
2495 || ((eqnote = find_reg_equal_equiv_note (insn))
2496 && ! may_trap_p (XEXP (eqnote, 0))))
2497 remove_note (insn, note);
2500 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2501 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2503 bool remove = false;
2505 /* There are three types of edges we need to handle correctly here: EH
2506 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2507 latter can appear when nonlocal gotos are used. */
2508 if (e->flags & EDGE_ABNORMAL_CALL)
2512 else if (can_nonlocal_goto (insn))
2514 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2516 else if (flag_tm && find_reg_note (insn, REG_TM, NULL))
2521 else if (e->flags & EDGE_EH)
2522 remove = !can_throw_internal (insn);
2527 df_set_bb_dirty (bb);
2540 /* We do care only about conditional jumps and simplejumps. */
2541 if (!any_condjump_p (insn)
2542 && !returnjump_p (insn)
2543 && !simplejump_p (insn))
2546 /* Branch probability/prediction notes are defined only for
2547 condjumps. We've possibly turned condjump into simplejump. */
2548 if (simplejump_p (insn))
2550 note = find_reg_note (insn, REG_BR_PROB, NULL);
2552 remove_note (insn, note);
2553 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2554 remove_note (insn, note);
2557 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2559 /* Avoid abnormal flags to leak from computed jumps turned
2560 into simplejumps. */
2562 e->flags &= ~EDGE_ABNORMAL;
2564 /* See if this edge is one we should keep. */
2565 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2566 /* A conditional jump can fall through into the next
2567 block, so we should keep the edge. */
2572 else if (e->dest != EXIT_BLOCK_PTR
2573 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2574 /* If the destination block is the target of the jump,
2580 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2581 /* If the destination block is the exit block, and this
2582 instruction is a return, then keep the edge. */
2587 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2588 /* Keep the edges that correspond to exceptions thrown by
2589 this instruction and rematerialize the EDGE_ABNORMAL
2590 flag we just cleared above. */
2592 e->flags |= EDGE_ABNORMAL;
2597 /* We do not need this edge. */
2598 df_set_bb_dirty (bb);
2603 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2607 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2612 /* Redistribute probabilities. */
2613 if (single_succ_p (bb))
2615 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2616 single_succ_edge (bb)->count = bb->count;
2620 note = find_reg_note (insn, REG_BR_PROB, NULL);
2624 b = BRANCH_EDGE (bb);
2625 f = FALLTHRU_EDGE (bb);
2626 b->probability = INTVAL (XEXP (note, 0));
2627 f->probability = REG_BR_PROB_BASE - b->probability;
2628 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2629 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2634 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2636 /* First, there should not be any EH or ABCALL edges resulting
2637 from non-local gotos and the like. If there were, we shouldn't
2638 have created the sibcall in the first place. Second, there
2639 should of course never have been a fallthru edge. */
2640 gcc_assert (single_succ_p (bb));
2641 gcc_assert (single_succ_edge (bb)->flags
2642 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2647 /* If we don't see a jump insn, we don't know exactly why the block would
2648 have been broken at this point. Look for a simple, non-fallthru edge,
2649 as these are only created by conditional branches. If we find such an
2650 edge we know that there used to be a jump here and can then safely
2651 remove all non-fallthru edges. */
2653 FOR_EACH_EDGE (e, ei, bb->succs)
2654 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2663 /* Remove all but the fake and fallthru edges. The fake edge may be
2664 the only successor for this block in the case of noreturn
2666 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2668 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2670 df_set_bb_dirty (bb);
2678 gcc_assert (single_succ_p (bb));
2680 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2681 single_succ_edge (bb)->count = bb->count;
2684 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2689 /* Search all basic blocks for potentially dead edges and purge them. Return
2690 true if some edge has been eliminated. */
2693 purge_all_dead_edges (void)
2700 bool purged_here = purge_dead_edges (bb);
2702 purged |= purged_here;
2708 /* This is used by a few passes that emit some instructions after abnormal
2709 calls, moving the basic block's end, while they in fact do want to emit
2710 them on the fallthru edge. Look for abnormal call edges, find backward
2711 the call in the block and insert the instructions on the edge instead.
2713 Similarly, handle instructions throwing exceptions internally.
2715 Return true when instructions have been found and inserted on edges. */
2718 fixup_abnormal_edges (void)
2720 bool inserted = false;
2728 /* Look for cases we are interested in - calls or instructions causing
2730 FOR_EACH_EDGE (e, ei, bb->succs)
2731 if ((e->flags & EDGE_ABNORMAL_CALL)
2732 || ((e->flags & (EDGE_ABNORMAL | EDGE_EH))
2733 == (EDGE_ABNORMAL | EDGE_EH)))
2736 if (e && !CALL_P (BB_END (bb)) && !can_throw_internal (BB_END (bb)))
2740 /* Get past the new insns generated. Allow notes, as the insns
2741 may be already deleted. */
2743 while ((NONJUMP_INSN_P (insn) || NOTE_P (insn))
2744 && !can_throw_internal (insn)
2745 && insn != BB_HEAD (bb))
2746 insn = PREV_INSN (insn);
2748 if (CALL_P (insn) || can_throw_internal (insn))
2752 e = find_fallthru_edge (bb->succs);
2754 stop = NEXT_INSN (BB_END (bb));
2757 for (insn = NEXT_INSN (insn); insn != stop; insn = next)
2759 next = NEXT_INSN (insn);
2764 /* Sometimes there's still the return value USE.
2765 If it's placed after a trapping call (i.e. that
2766 call is the last insn anyway), we have no fallthru
2767 edge. Simply delete this use and don't try to insert
2768 on the non-existent edge. */
2769 if (GET_CODE (PATTERN (insn)) != USE)
2771 /* We're not deleting it, we're moving it. */
2772 INSN_DELETED_P (insn) = 0;
2773 PREV_INSN (insn) = NULL_RTX;
2774 NEXT_INSN (insn) = NULL_RTX;
2776 insert_insn_on_edge (insn, e);
2780 else if (!BARRIER_P (insn))
2781 set_block_for_insn (insn, NULL);
2785 /* It may be that we don't find any trapping insn. In this
2786 case we discovered quite late that the insn that had been
2787 marked as can_throw_internal in fact couldn't trap at all.
2788 So we should in fact delete the EH edges out of the block. */
2790 purge_dead_edges (bb);
2797 /* Cut the insns from FIRST to LAST out of the insns stream. */
2800 unlink_insn_chain (rtx first, rtx last)
2802 rtx prevfirst = PREV_INSN (first);
2803 rtx nextlast = NEXT_INSN (last);
2805 PREV_INSN (first) = NULL;
2806 NEXT_INSN (last) = NULL;
2808 NEXT_INSN (prevfirst) = nextlast;
2810 PREV_INSN (nextlast) = prevfirst;
2812 set_last_insn (prevfirst);
2814 set_first_insn (nextlast);
2818 /* Skip over inter-block insns occurring after BB which are typically
2819 associated with BB (e.g., barriers). If there are any such insns,
2820 we return the last one. Otherwise, we return the end of BB. */
2823 skip_insns_after_block (basic_block bb)
2825 rtx insn, last_insn, next_head, prev;
2827 next_head = NULL_RTX;
2828 if (bb->next_bb != EXIT_BLOCK_PTR)
2829 next_head = BB_HEAD (bb->next_bb);
2831 for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; )
2833 if (insn == next_head)
2836 switch (GET_CODE (insn))
2843 switch (NOTE_KIND (insn))
2845 case NOTE_INSN_BLOCK_END:
2855 if (NEXT_INSN (insn)
2856 && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
2858 insn = NEXT_INSN (insn);
2871 /* It is possible to hit contradictory sequence. For instance:
2877 Where barrier belongs to jump_insn, but the note does not. This can be
2878 created by removing the basic block originally following
2879 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
2881 for (insn = last_insn; insn != BB_END (bb); insn = prev)
2883 prev = PREV_INSN (insn);
2885 switch (NOTE_KIND (insn))
2887 case NOTE_INSN_BLOCK_END:
2890 case NOTE_INSN_DELETED:
2891 case NOTE_INSN_DELETED_LABEL:
2892 case NOTE_INSN_DELETED_DEBUG_LABEL:
2895 reorder_insns (insn, insn, last_insn);
2902 /* Locate or create a label for a given basic block. */
2905 label_for_bb (basic_block bb)
2907 rtx label = BB_HEAD (bb);
2909 if (!LABEL_P (label))
2912 fprintf (dump_file, "Emitting label for block %d\n", bb->index);
2914 label = block_label (bb);
2920 /* Locate the effective beginning and end of the insn chain for each
2921 block, as defined by skip_insns_after_block above. */
2924 record_effective_endpoints (void)
2930 for (insn = get_insns ();
2933 && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK;
2934 insn = NEXT_INSN (insn))
2936 /* No basic blocks at all? */
2939 if (PREV_INSN (insn))
2940 cfg_layout_function_header =
2941 unlink_insn_chain (get_insns (), PREV_INSN (insn));
2943 cfg_layout_function_header = NULL_RTX;
2945 next_insn = get_insns ();
2950 if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb))
2951 BB_HEADER (bb) = unlink_insn_chain (next_insn,
2952 PREV_INSN (BB_HEAD (bb)));
2953 end = skip_insns_after_block (bb);
2954 if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end)
2955 BB_FOOTER (bb) = unlink_insn_chain (NEXT_INSN (BB_END (bb)), end);
2956 next_insn = NEXT_INSN (BB_END (bb));
2959 cfg_layout_function_footer = next_insn;
2960 if (cfg_layout_function_footer)
2961 cfg_layout_function_footer = unlink_insn_chain (cfg_layout_function_footer, get_last_insn ());
2965 into_cfg_layout_mode (void)
2967 cfg_layout_initialize (0);
2972 outof_cfg_layout_mode (void)
2977 if (bb->next_bb != EXIT_BLOCK_PTR)
2978 bb->aux = bb->next_bb;
2980 cfg_layout_finalize ();
2985 struct rtl_opt_pass pass_into_cfg_layout_mode =
2989 "into_cfglayout", /* name */
2991 into_cfg_layout_mode, /* execute */
2994 0, /* static_pass_number */
2996 0, /* properties_required */
2997 PROP_cfglayout, /* properties_provided */
2998 0, /* properties_destroyed */
2999 0, /* todo_flags_start */
3000 0 /* todo_flags_finish */
3004 struct rtl_opt_pass pass_outof_cfg_layout_mode =
3008 "outof_cfglayout", /* name */
3010 outof_cfg_layout_mode, /* execute */
3013 0, /* static_pass_number */
3015 0, /* properties_required */
3016 0, /* properties_provided */
3017 PROP_cfglayout, /* properties_destroyed */
3018 0, /* todo_flags_start */
3019 0 /* todo_flags_finish */
3024 /* Link the basic blocks in the correct order, compacting the basic
3025 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3026 function also clears the basic block header and footer fields.
3028 This function is usually called after a pass (e.g. tracer) finishes
3029 some transformations while in cfglayout mode. The required sequence
3030 of the basic blocks is in a linked list along the bb->aux field.
3031 This functions re-links the basic block prev_bb and next_bb pointers
3032 accordingly, and it compacts and renumbers the blocks.
3034 FIXME: This currently works only for RTL, but the only RTL-specific
3035 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3036 to GIMPLE a long time ago, but it doesn't relink the basic block
3037 chain. It could do that (to give better initial RTL) if this function
3038 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3041 relink_block_chain (bool stay_in_cfglayout_mode)
3043 basic_block bb, prev_bb;
3046 /* Maybe dump the re-ordered sequence. */
3049 fprintf (dump_file, "Reordered sequence:\n");
3050 for (bb = ENTRY_BLOCK_PTR->next_bb, index = NUM_FIXED_BLOCKS;
3052 bb = (basic_block) bb->aux, index++)
3054 fprintf (dump_file, " %i ", index);
3055 if (get_bb_original (bb))
3056 fprintf (dump_file, "duplicate of %i ",
3057 get_bb_original (bb)->index);
3058 else if (forwarder_block_p (bb)
3059 && !LABEL_P (BB_HEAD (bb)))
3060 fprintf (dump_file, "compensation ");
3062 fprintf (dump_file, "bb %i ", bb->index);
3063 fprintf (dump_file, " [%i]\n", bb->frequency);
3067 /* Now reorder the blocks. */
3068 prev_bb = ENTRY_BLOCK_PTR;
3069 bb = ENTRY_BLOCK_PTR->next_bb;
3070 for (; bb; prev_bb = bb, bb = (basic_block) bb->aux)
3072 bb->prev_bb = prev_bb;
3073 prev_bb->next_bb = bb;
3075 prev_bb->next_bb = EXIT_BLOCK_PTR;
3076 EXIT_BLOCK_PTR->prev_bb = prev_bb;
3078 /* Then, clean up the aux fields. */
3082 if (!stay_in_cfglayout_mode)
3083 BB_HEADER (bb) = BB_FOOTER (bb) = NULL;
3086 /* Maybe reset the original copy tables, they are not valid anymore
3087 when we renumber the basic blocks in compact_blocks. If we are
3088 are going out of cfglayout mode, don't re-allocate the tables. */
3089 free_original_copy_tables ();
3090 if (stay_in_cfglayout_mode)
3091 initialize_original_copy_tables ();
3093 /* Finally, put basic_block_info in the new order. */
3098 /* Given a reorder chain, rearrange the code to match. */
3101 fixup_reorder_chain (void)
3106 if (cfg_layout_function_header)
3108 set_first_insn (cfg_layout_function_header);
3109 insn = cfg_layout_function_header;
3110 while (NEXT_INSN (insn))
3111 insn = NEXT_INSN (insn);
3114 /* First do the bulk reordering -- rechain the blocks without regard to
3115 the needed changes to jumps and labels. */
3117 for (bb = ENTRY_BLOCK_PTR->next_bb; bb; bb = (basic_block) bb->aux)
3122 NEXT_INSN (insn) = BB_HEADER (bb);
3124 set_first_insn (BB_HEADER (bb));
3125 PREV_INSN (BB_HEADER (bb)) = insn;
3126 insn = BB_HEADER (bb);
3127 while (NEXT_INSN (insn))
3128 insn = NEXT_INSN (insn);
3131 NEXT_INSN (insn) = BB_HEAD (bb);
3133 set_first_insn (BB_HEAD (bb));
3134 PREV_INSN (BB_HEAD (bb)) = insn;
3138 NEXT_INSN (insn) = BB_FOOTER (bb);
3139 PREV_INSN (BB_FOOTER (bb)) = insn;
3140 while (NEXT_INSN (insn))
3141 insn = NEXT_INSN (insn);
3145 NEXT_INSN (insn) = cfg_layout_function_footer;
3146 if (cfg_layout_function_footer)
3147 PREV_INSN (cfg_layout_function_footer) = insn;
3149 while (NEXT_INSN (insn))
3150 insn = NEXT_INSN (insn);
3152 set_last_insn (insn);
3153 #ifdef ENABLE_CHECKING
3154 verify_insn_chain ();
3157 /* Now add jumps and labels as needed to match the blocks new
3160 for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = (basic_block) bb->aux)
3162 edge e_fall, e_taken, e;
3164 rtx ret_label = NULL_RTX;
3165 basic_block nb, src_bb;
3168 if (EDGE_COUNT (bb->succs) == 0)
3171 /* Find the old fallthru edge, and another non-EH edge for
3173 e_taken = e_fall = NULL;
3175 FOR_EACH_EDGE (e, ei, bb->succs)
3176 if (e->flags & EDGE_FALLTHRU)
3178 else if (! (e->flags & EDGE_EH))
3181 bb_end_insn = BB_END (bb);
3182 if (JUMP_P (bb_end_insn))
3184 ret_label = JUMP_LABEL (bb_end_insn);
3185 if (any_condjump_p (bb_end_insn))
3187 /* This might happen if the conditional jump has side
3188 effects and could therefore not be optimized away.
3189 Make the basic block to end with a barrier in order
3190 to prevent rtl_verify_flow_info from complaining. */
3193 gcc_assert (!onlyjump_p (bb_end_insn)
3194 || returnjump_p (bb_end_insn));
3195 BB_FOOTER (bb) = emit_barrier_after (bb_end_insn);
3199 /* If the old fallthru is still next, nothing to do. */
3200 if (bb->aux == e_fall->dest
3201 || e_fall->dest == EXIT_BLOCK_PTR)
3204 /* The degenerated case of conditional jump jumping to the next
3205 instruction can happen for jumps with side effects. We need
3206 to construct a forwarder block and this will be done just
3207 fine by force_nonfallthru below. */
3211 /* There is another special case: if *neither* block is next,
3212 such as happens at the very end of a function, then we'll
3213 need to add a new unconditional jump. Choose the taken
3214 edge based on known or assumed probability. */
3215 else if (bb->aux != e_taken->dest)
3217 rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0);
3220 && INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2
3221 && invert_jump (bb_end_insn,
3222 (e_fall->dest == EXIT_BLOCK_PTR
3224 : label_for_bb (e_fall->dest)), 0))
3226 e_fall->flags &= ~EDGE_FALLTHRU;
3227 gcc_checking_assert (could_fall_through
3228 (e_taken->src, e_taken->dest));
3229 e_taken->flags |= EDGE_FALLTHRU;
3230 update_br_prob_note (bb);
3231 e = e_fall, e_fall = e_taken, e_taken = e;
3235 /* If the "jumping" edge is a crossing edge, and the fall
3236 through edge is non-crossing, leave things as they are. */
3237 else if ((e_taken->flags & EDGE_CROSSING)
3238 && !(e_fall->flags & EDGE_CROSSING))
3241 /* Otherwise we can try to invert the jump. This will
3242 basically never fail, however, keep up the pretense. */
3243 else if (invert_jump (bb_end_insn,
3244 (e_fall->dest == EXIT_BLOCK_PTR
3246 : label_for_bb (e_fall->dest)), 0))
3248 e_fall->flags &= ~EDGE_FALLTHRU;
3249 gcc_checking_assert (could_fall_through
3250 (e_taken->src, e_taken->dest));
3251 e_taken->flags |= EDGE_FALLTHRU;
3252 update_br_prob_note (bb);
3253 if (LABEL_NUSES (ret_label) == 0
3254 && single_pred_p (e_taken->dest))
3255 delete_insn (ret_label);
3259 else if (extract_asm_operands (PATTERN (bb_end_insn)) != NULL)
3261 /* If the old fallthru is still next or if
3262 asm goto doesn't have a fallthru (e.g. when followed by
3263 __builtin_unreachable ()), nothing to do. */
3265 || bb->aux == e_fall->dest
3266 || e_fall->dest == EXIT_BLOCK_PTR)
3269 /* Otherwise we'll have to use the fallthru fixup below. */
3273 /* Otherwise we have some return, switch or computed
3274 jump. In the 99% case, there should not have been a
3276 gcc_assert (returnjump_p (bb_end_insn) || !e_fall);
3282 /* No fallthru implies a noreturn function with EH edges, or
3283 something similarly bizarre. In any case, we don't need to
3288 /* If the fallthru block is still next, nothing to do. */
3289 if (bb->aux == e_fall->dest)
3292 /* A fallthru to exit block. */
3293 if (e_fall->dest == EXIT_BLOCK_PTR)
3297 /* We got here if we need to add a new jump insn.
3298 Note force_nonfallthru can delete E_FALL and thus we have to
3299 save E_FALL->src prior to the call to force_nonfallthru. */
3300 src_bb = e_fall->src;
3301 nb = force_nonfallthru_and_redirect (e_fall, e_fall->dest, ret_label);
3306 /* Don't process this new block. */
3309 /* Make sure new bb is tagged for correct section (same as
3310 fall-thru source, since you cannot fall-thru across
3311 section boundaries). */
3312 BB_COPY_PARTITION (src_bb, single_pred (bb));
3313 if (flag_reorder_blocks_and_partition
3314 && targetm_common.have_named_sections
3315 && JUMP_P (BB_END (bb))
3316 && !any_condjump_p (BB_END (bb))
3317 && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING))
3318 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
3322 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3324 /* Annoying special case - jump around dead jumptables left in the code. */
3327 edge e = find_fallthru_edge (bb->succs);
3329 if (e && !can_fallthru (e->src, e->dest))
3330 force_nonfallthru (e);
3333 /* Ensure goto_locus from edges has some instructions with that locus
3341 FOR_EACH_EDGE (e, ei, bb->succs)
3342 if (LOCATION_LOCUS (e->goto_locus) != UNKNOWN_LOCATION
3343 && !(e->flags & EDGE_ABNORMAL))
3347 basic_block dest, nb;
3350 insn = BB_END (e->src);
3351 end = PREV_INSN (BB_HEAD (e->src));
3353 && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn)))
3354 insn = PREV_INSN (insn);
3356 && INSN_LOCATION (insn) == e->goto_locus)
3358 if (simplejump_p (BB_END (e->src))
3359 && !INSN_HAS_LOCATION (BB_END (e->src)))
3361 INSN_LOCATION (BB_END (e->src)) = e->goto_locus;
3365 if (dest == EXIT_BLOCK_PTR)
3367 /* Non-fallthru edges to the exit block cannot be split. */
3368 if (!(e->flags & EDGE_FALLTHRU))
3373 insn = BB_HEAD (dest);
3374 end = NEXT_INSN (BB_END (dest));
3375 while (insn != end && !NONDEBUG_INSN_P (insn))
3376 insn = NEXT_INSN (insn);
3377 if (insn != end && INSN_HAS_LOCATION (insn)
3378 && INSN_LOCATION (insn) == e->goto_locus)
3381 nb = split_edge (e);
3382 if (!INSN_P (BB_END (nb)))
3383 BB_END (nb) = emit_insn_after_noloc (gen_nop (), BB_END (nb),
3385 INSN_LOCATION (BB_END (nb)) = e->goto_locus;
3387 /* If there are other incoming edges to the destination block
3388 with the same goto locus, redirect them to the new block as
3389 well, this can prevent other such blocks from being created
3390 in subsequent iterations of the loop. */
3391 for (ei2 = ei_start (dest->preds); (e2 = ei_safe_edge (ei2)); )
3392 if (LOCATION_LOCUS (e2->goto_locus) != UNKNOWN_LOCATION
3393 && !(e2->flags & (EDGE_ABNORMAL | EDGE_FALLTHRU))
3394 && e->goto_locus == e2->goto_locus)
3395 redirect_edge_and_branch (e2, nb);
3402 /* Perform sanity checks on the insn chain.
3403 1. Check that next/prev pointers are consistent in both the forward and
3405 2. Count insns in chain, going both directions, and check if equal.
3406 3. Check that get_last_insn () returns the actual end of chain. */
3409 verify_insn_chain (void)
3411 rtx x, prevx, nextx;
3412 int insn_cnt1, insn_cnt2;
3414 for (prevx = NULL, insn_cnt1 = 1, x = get_insns ();
3416 prevx = x, insn_cnt1++, x = NEXT_INSN (x))
3417 gcc_assert (PREV_INSN (x) == prevx);
3419 gcc_assert (prevx == get_last_insn ());
3421 for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn ();
3423 nextx = x, insn_cnt2++, x = PREV_INSN (x))
3424 gcc_assert (NEXT_INSN (x) == nextx);
3426 gcc_assert (insn_cnt1 == insn_cnt2);
3429 /* If we have assembler epilogues, the block falling through to exit must
3430 be the last one in the reordered chain when we reach final. Ensure
3431 that this condition is met. */
3433 fixup_fallthru_exit_predecessor (void)
3436 basic_block bb = NULL;
3438 /* This transformation is not valid before reload, because we might
3439 separate a call from the instruction that copies the return
3441 gcc_assert (reload_completed);
3443 e = find_fallthru_edge (EXIT_BLOCK_PTR->preds);
3449 basic_block c = ENTRY_BLOCK_PTR->next_bb;
3451 /* If the very first block is the one with the fall-through exit
3452 edge, we have to split that block. */
3455 bb = split_block (bb, NULL)->dest;
3458 BB_FOOTER (bb) = BB_FOOTER (c);
3459 BB_FOOTER (c) = NULL;
3462 while (c->aux != bb)
3463 c = (basic_block) c->aux;
3467 c = (basic_block) c->aux;
3474 /* In case there are more than one fallthru predecessors of exit, force that
3475 there is only one. */
3478 force_one_exit_fallthru (void)
3480 edge e, predecessor = NULL;
3483 basic_block forwarder, bb;
3485 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3486 if (e->flags & EDGE_FALLTHRU)
3488 if (predecessor == NULL)
3500 /* Exit has several fallthru predecessors. Create a forwarder block for
3502 forwarder = split_edge (predecessor);
3503 for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
3505 if (e->src == forwarder
3506 || !(e->flags & EDGE_FALLTHRU))
3509 redirect_edge_and_branch_force (e, forwarder);
3512 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
3516 if (bb->aux == NULL && bb != forwarder)
3518 bb->aux = forwarder;
3524 /* Return true in case it is possible to duplicate the basic block BB. */
3527 cfg_layout_can_duplicate_bb_p (const_basic_block bb)
3529 /* Do not attempt to duplicate tablejumps, as we need to unshare
3530 the dispatch table. This is difficult to do, as the instructions
3531 computing jump destination may be hoisted outside the basic block. */
3532 if (tablejump_p (BB_END (bb), NULL, NULL))
3535 /* Do not duplicate blocks containing insns that can't be copied. */
3536 if (targetm.cannot_copy_insn_p)
3538 rtx insn = BB_HEAD (bb);
3541 if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn))
3543 if (insn == BB_END (bb))
3545 insn = NEXT_INSN (insn);
3553 duplicate_insn_chain (rtx from, rtx to)
3555 rtx insn, last, copy;
3557 /* Avoid updating of boundaries of previous basic block. The
3558 note will get removed from insn stream in fixup. */
3559 last = emit_note (NOTE_INSN_DELETED);
3561 /* Create copy at the end of INSN chain. The chain will
3562 be reordered later. */
3563 for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn))
3565 switch (GET_CODE (insn))
3568 /* Don't duplicate label debug insns. */
3569 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn)) == LABEL_DECL)
3575 /* Avoid copying of dispatch tables. We never duplicate
3576 tablejumps, so this can hit only in case the table got
3577 moved far from original jump. */
3578 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
3579 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
3581 /* Avoid copying following barrier as well if any
3582 (and debug insns in between). */
3585 for (next = NEXT_INSN (insn);
3586 next != NEXT_INSN (to);
3587 next = NEXT_INSN (next))
3588 if (!DEBUG_INSN_P (next))
3590 if (next != NEXT_INSN (to) && BARRIER_P (next))
3594 copy = emit_copy_of_insn_after (insn, get_last_insn ());
3595 if (JUMP_P (insn) && JUMP_LABEL (insn) != NULL_RTX
3596 && ANY_RETURN_P (JUMP_LABEL (insn)))
3597 JUMP_LABEL (copy) = JUMP_LABEL (insn);
3598 maybe_copy_prologue_epilogue_insn (insn, copy);
3609 switch (NOTE_KIND (insn))
3611 /* In case prologue is empty and function contain label
3612 in first BB, we may want to copy the block. */
3613 case NOTE_INSN_PROLOGUE_END:
3615 case NOTE_INSN_DELETED:
3616 case NOTE_INSN_DELETED_LABEL:
3617 case NOTE_INSN_DELETED_DEBUG_LABEL:
3618 /* No problem to strip these. */
3619 case NOTE_INSN_FUNCTION_BEG:
3620 /* There is always just single entry to function. */
3621 case NOTE_INSN_BASIC_BLOCK:
3624 case NOTE_INSN_EPILOGUE_BEG:
3625 case NOTE_INSN_SWITCH_TEXT_SECTIONS:
3626 emit_note_copy (insn);
3630 /* All other notes should have already been eliminated. */
3638 insn = NEXT_INSN (last);
3643 /* Create a duplicate of the basic block BB. */
3646 cfg_layout_duplicate_bb (basic_block bb)
3651 insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb));
3652 new_bb = create_basic_block (insn,
3653 insn ? get_last_insn () : NULL,
3654 EXIT_BLOCK_PTR->prev_bb);
3656 BB_COPY_PARTITION (new_bb, bb);
3659 insn = BB_HEADER (bb);
3660 while (NEXT_INSN (insn))
3661 insn = NEXT_INSN (insn);
3662 insn = duplicate_insn_chain (BB_HEADER (bb), insn);
3664 BB_HEADER (new_bb) = unlink_insn_chain (insn, get_last_insn ());
3669 insn = BB_FOOTER (bb);
3670 while (NEXT_INSN (insn))
3671 insn = NEXT_INSN (insn);
3672 insn = duplicate_insn_chain (BB_FOOTER (bb), insn);
3674 BB_FOOTER (new_bb) = unlink_insn_chain (insn, get_last_insn ());
3681 /* Main entry point to this module - initialize the datastructures for
3682 CFG layout changes. It keeps LOOPS up-to-date if not null.
3684 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
3687 cfg_layout_initialize (unsigned int flags)
3692 initialize_original_copy_tables ();
3694 cfg_layout_rtl_register_cfg_hooks ();
3696 record_effective_endpoints ();
3698 /* Make sure that the targets of non local gotos are marked. */
3699 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
3701 bb = BLOCK_FOR_INSN (XEXP (x, 0));
3702 bb->flags |= BB_NON_LOCAL_GOTO_TARGET;
3705 cleanup_cfg (CLEANUP_CFGLAYOUT | flags);
3708 /* Splits superblocks. */
3710 break_superblocks (void)
3712 sbitmap superblocks;
3716 superblocks = sbitmap_alloc (last_basic_block);
3717 sbitmap_zero (superblocks);
3720 if (bb->flags & BB_SUPERBLOCK)
3722 bb->flags &= ~BB_SUPERBLOCK;
3723 SET_BIT (superblocks, bb->index);
3729 rebuild_jump_labels (get_insns ());
3730 find_many_sub_basic_blocks (superblocks);
3736 /* Finalize the changes: reorder insn list according to the sequence specified
3737 by aux pointers, enter compensation code, rebuild scope forest. */
3740 cfg_layout_finalize (void)
3742 #ifdef ENABLE_CHECKING
3743 verify_flow_info ();
3745 force_one_exit_fallthru ();
3746 rtl_register_cfg_hooks ();
3747 if (reload_completed
3748 #ifdef HAVE_epilogue
3752 fixup_fallthru_exit_predecessor ();
3753 fixup_reorder_chain ();
3755 rebuild_jump_labels (get_insns ());
3756 delete_dead_jumptables ();
3758 #ifdef ENABLE_CHECKING
3759 verify_insn_chain ();
3760 verify_flow_info ();
3765 /* Same as split_block but update cfg_layout structures. */
3768 cfg_layout_split_block (basic_block bb, void *insnp)
3770 rtx insn = (rtx) insnp;
3771 basic_block new_bb = rtl_split_block (bb, insn);
3773 BB_FOOTER (new_bb) = BB_FOOTER (bb);
3774 BB_FOOTER (bb) = NULL;
3779 /* Redirect Edge to DEST. */
3781 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
3783 basic_block src = e->src;
3786 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3789 if (e->dest == dest)
3792 if (e->src != ENTRY_BLOCK_PTR
3793 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
3795 df_set_bb_dirty (src);
3799 if (e->src == ENTRY_BLOCK_PTR
3800 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
3803 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
3804 e->src->index, dest->index);
3806 df_set_bb_dirty (e->src);
3807 redirect_edge_succ (e, dest);
3811 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
3812 in the case the basic block appears to be in sequence. Avoid this
3815 if (e->flags & EDGE_FALLTHRU)
3817 /* Redirect any branch edges unified with the fallthru one. */
3818 if (JUMP_P (BB_END (src))
3819 && label_is_jump_target_p (BB_HEAD (e->dest),
3825 fprintf (dump_file, "Fallthru edge unified with branch "
3826 "%i->%i redirected to %i\n",
3827 e->src->index, e->dest->index, dest->index);
3828 e->flags &= ~EDGE_FALLTHRU;
3829 redirected = redirect_branch_edge (e, dest);
3830 gcc_assert (redirected);
3831 redirected->flags |= EDGE_FALLTHRU;
3832 df_set_bb_dirty (redirected->src);
3835 /* In case we are redirecting fallthru edge to the branch edge
3836 of conditional jump, remove it. */
3837 if (EDGE_COUNT (src->succs) == 2)
3839 /* Find the edge that is different from E. */
3840 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
3843 && any_condjump_p (BB_END (src))
3844 && onlyjump_p (BB_END (src)))
3845 delete_insn (BB_END (src));
3848 fprintf (dump_file, "Redirecting fallthru edge %i->%i to %i\n",
3849 e->src->index, e->dest->index, dest->index);
3850 ret = redirect_edge_succ_nodup (e, dest);
3853 ret = redirect_branch_edge (e, dest);
3855 /* We don't want simplejumps in the insn stream during cfglayout. */
3856 gcc_assert (!simplejump_p (BB_END (src)));
3858 df_set_bb_dirty (src);
3862 /* Simple wrapper as we always can redirect fallthru edges. */
3864 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
3866 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
3868 gcc_assert (redirected);
3872 /* Same as delete_basic_block but update cfg_layout structures. */
3875 cfg_layout_delete_block (basic_block bb)
3877 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
3881 next = BB_HEAD (bb);
3883 NEXT_INSN (prev) = BB_HEADER (bb);
3885 set_first_insn (BB_HEADER (bb));
3886 PREV_INSN (BB_HEADER (bb)) = prev;
3887 insn = BB_HEADER (bb);
3888 while (NEXT_INSN (insn))
3889 insn = NEXT_INSN (insn);
3890 NEXT_INSN (insn) = next;
3891 PREV_INSN (next) = insn;
3893 next = NEXT_INSN (BB_END (bb));
3896 insn = BB_FOOTER (bb);
3899 if (BARRIER_P (insn))
3901 if (PREV_INSN (insn))
3902 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
3904 BB_FOOTER (bb) = NEXT_INSN (insn);
3905 if (NEXT_INSN (insn))
3906 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
3910 insn = NEXT_INSN (insn);
3915 NEXT_INSN (insn) = BB_FOOTER (bb);
3916 PREV_INSN (BB_FOOTER (bb)) = insn;
3917 while (NEXT_INSN (insn))
3918 insn = NEXT_INSN (insn);
3919 NEXT_INSN (insn) = next;
3921 PREV_INSN (next) = insn;
3923 set_last_insn (insn);
3926 if (bb->next_bb != EXIT_BLOCK_PTR)
3927 to = &BB_HEADER (bb->next_bb);
3929 to = &cfg_layout_function_footer;
3931 rtl_delete_block (bb);
3934 prev = NEXT_INSN (prev);
3936 prev = get_insns ();
3938 next = PREV_INSN (next);
3940 next = get_last_insn ();
3942 if (next && NEXT_INSN (next) != prev)
3944 remaints = unlink_insn_chain (prev, next);
3946 while (NEXT_INSN (insn))
3947 insn = NEXT_INSN (insn);
3948 NEXT_INSN (insn) = *to;
3950 PREV_INSN (*to) = insn;
3955 /* Return true when blocks A and B can be safely merged. */
3958 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
3960 /* If we are partitioning hot/cold basic blocks, we don't want to
3961 mess up unconditional or indirect jumps that cross between hot
3964 Basic block partitioning may result in some jumps that appear to
3965 be optimizable (or blocks that appear to be mergeable), but which really
3966 must be left untouched (they are required to make it safely across
3967 partition boundaries). See the comments at the top of
3968 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3970 if (BB_PARTITION (a) != BB_PARTITION (b))
3973 /* Protect the loop latches. */
3974 if (current_loops && b->loop_father->latch == b)
3977 /* If we would end up moving B's instructions, make sure it doesn't fall
3978 through into the exit block, since we cannot recover from a fallthrough
3979 edge into the exit block occurring in the middle of a function. */
3980 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
3982 edge e = find_fallthru_edge (b->succs);
3983 if (e && e->dest == EXIT_BLOCK_PTR)
3987 /* There must be exactly one edge in between the blocks. */
3988 return (single_succ_p (a)
3989 && single_succ (a) == b
3990 && single_pred_p (b) == 1
3992 /* Must be simple edge. */
3993 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
3994 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
3995 /* If the jump insn has side effects, we can't kill the edge.
3996 When not optimizing, try_redirect_by_replacing_jump will
3997 not allow us to redirect an edge by replacing a table jump. */
3998 && (!JUMP_P (BB_END (a))
3999 || ((!optimize || reload_completed)
4000 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
4003 /* Merge block A and B. The blocks must be mergeable. */
4006 cfg_layout_merge_blocks (basic_block a, basic_block b)
4008 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
4011 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b));
4014 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
4017 /* If there was a CODE_LABEL beginning B, delete it. */
4018 if (LABEL_P (BB_HEAD (b)))
4020 delete_insn (BB_HEAD (b));
4023 /* We should have fallthru edge in a, or we can do dummy redirection to get
4025 if (JUMP_P (BB_END (a)))
4026 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
4027 gcc_assert (!JUMP_P (BB_END (a)));
4029 /* When not optimizing CFG and the edge is the only place in RTL which holds
4030 some unique locus, emit a nop with that locus in between. */
4032 emit_nop_for_unique_locus_between (a, b);
4034 /* Possible line number notes should appear in between. */
4037 rtx first = BB_END (a), last;
4039 last = emit_insn_after_noloc (BB_HEADER (b), BB_END (a), a);
4040 /* The above might add a BARRIER as BB_END, but as barriers
4041 aren't valid parts of a bb, remove_insn doesn't update
4042 BB_END if it is a barrier. So adjust BB_END here. */
4043 while (BB_END (a) != first && BARRIER_P (BB_END (a)))
4044 BB_END (a) = PREV_INSN (BB_END (a));
4045 delete_insn_chain (NEXT_INSN (first), last, false);
4046 BB_HEADER (b) = NULL;
4049 /* In the case basic blocks are not adjacent, move them around. */
4050 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
4052 insn = unlink_insn_chain (BB_HEAD (b), BB_END (b));
4054 emit_insn_after_noloc (insn, BB_END (a), a);
4056 /* Otherwise just re-associate the instructions. */
4060 BB_END (a) = BB_END (b);
4063 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4064 We need to explicitly call. */
4065 update_bb_for_insn_chain (insn, BB_END (b), a);
4067 /* Skip possible DELETED_LABEL insn. */
4068 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
4069 insn = NEXT_INSN (insn);
4070 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
4074 df_bb_delete (b->index);
4076 /* Possible tablejumps and barriers should appear after the block. */
4080 BB_FOOTER (a) = BB_FOOTER (b);
4083 rtx last = BB_FOOTER (a);
4085 while (NEXT_INSN (last))
4086 last = NEXT_INSN (last);
4087 NEXT_INSN (last) = BB_FOOTER (b);
4088 PREV_INSN (BB_FOOTER (b)) = last;
4090 BB_FOOTER (b) = NULL;
4093 /* If B was a forwarder block, propagate the locus on the edge. */
4095 && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) != UNKNOWN_LOCATION)
4096 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
4099 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
4105 cfg_layout_split_edge (edge e)
4107 basic_block new_bb =
4108 create_basic_block (e->src != ENTRY_BLOCK_PTR
4109 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
4112 if (e->dest == EXIT_BLOCK_PTR)
4113 BB_COPY_PARTITION (new_bb, e->src);
4115 BB_COPY_PARTITION (new_bb, e->dest);
4116 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
4117 redirect_edge_and_branch_force (e, new_bb);
4122 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4125 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
4129 /* Return true if BB contains only labels or non-executable
4133 rtl_block_empty_p (basic_block bb)
4137 if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR)
4140 FOR_BB_INSNS (bb, insn)
4141 if (NONDEBUG_INSN_P (insn) && !any_uncondjump_p (insn))
4147 /* Split a basic block if it ends with a conditional branch and if
4148 the other part of the block is not empty. */
4151 rtl_split_block_before_cond_jump (basic_block bb)
4154 rtx split_point = NULL;
4156 bool found_code = false;
4158 FOR_BB_INSNS (bb, insn)
4160 if (any_condjump_p (insn))
4162 else if (NONDEBUG_INSN_P (insn))
4167 /* Did not find everything. */
4168 if (found_code && split_point)
4169 return split_block (bb, split_point)->dest;
4174 /* Return 1 if BB ends with a call, possibly followed by some
4175 instructions that must stay with the call, 0 otherwise. */
4178 rtl_block_ends_with_call_p (basic_block bb)
4180 rtx insn = BB_END (bb);
4182 while (!CALL_P (insn)
4183 && insn != BB_HEAD (bb)
4184 && (keep_with_call_p (insn)
4186 || DEBUG_INSN_P (insn)))
4187 insn = PREV_INSN (insn);
4188 return (CALL_P (insn));
4191 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4194 rtl_block_ends_with_condjump_p (const_basic_block bb)
4196 return any_condjump_p (BB_END (bb));
4199 /* Return true if we need to add fake edge to exit.
4200 Helper function for rtl_flow_call_edges_add. */
4203 need_fake_edge_p (const_rtx insn)
4209 && !SIBLING_CALL_P (insn)
4210 && !find_reg_note (insn, REG_NORETURN, NULL)
4211 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
4214 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
4215 && MEM_VOLATILE_P (PATTERN (insn)))
4216 || (GET_CODE (PATTERN (insn)) == PARALLEL
4217 && asm_noperands (insn) != -1
4218 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
4219 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
4222 /* Add fake edges to the function exit for any non constant and non noreturn
4223 calls, volatile inline assembly in the bitmap of blocks specified by
4224 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4227 The goal is to expose cases in which entering a basic block does not imply
4228 that all subsequent instructions must be executed. */
4231 rtl_flow_call_edges_add (sbitmap blocks)
4234 int blocks_split = 0;
4235 int last_bb = last_basic_block;
4236 bool check_last_block = false;
4238 if (n_basic_blocks == NUM_FIXED_BLOCKS)
4242 check_last_block = true;
4244 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
4246 /* In the last basic block, before epilogue generation, there will be
4247 a fallthru edge to EXIT. Special care is required if the last insn
4248 of the last basic block is a call because make_edge folds duplicate
4249 edges, which would result in the fallthru edge also being marked
4250 fake, which would result in the fallthru edge being removed by
4251 remove_fake_edges, which would result in an invalid CFG.
4253 Moreover, we can't elide the outgoing fake edge, since the block
4254 profiler needs to take this into account in order to solve the minimal
4255 spanning tree in the case that the call doesn't return.
4257 Handle this by adding a dummy instruction in a new last basic block. */
4258 if (check_last_block)
4260 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
4261 rtx insn = BB_END (bb);
4263 /* Back up past insns that must be kept in the same block as a call. */
4264 while (insn != BB_HEAD (bb)
4265 && keep_with_call_p (insn))
4266 insn = PREV_INSN (insn);
4268 if (need_fake_edge_p (insn))
4272 e = find_edge (bb, EXIT_BLOCK_PTR);
4275 insert_insn_on_edge (gen_use (const0_rtx), e);
4276 commit_edge_insertions ();
4281 /* Now add fake edges to the function exit for any non constant
4282 calls since there is no way that we can determine if they will
4285 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
4287 basic_block bb = BASIC_BLOCK (i);
4294 if (blocks && !TEST_BIT (blocks, i))
4297 for (insn = BB_END (bb); ; insn = prev_insn)
4299 prev_insn = PREV_INSN (insn);
4300 if (need_fake_edge_p (insn))
4303 rtx split_at_insn = insn;
4305 /* Don't split the block between a call and an insn that should
4306 remain in the same block as the call. */
4308 while (split_at_insn != BB_END (bb)
4309 && keep_with_call_p (NEXT_INSN (split_at_insn)))
4310 split_at_insn = NEXT_INSN (split_at_insn);
4312 /* The handling above of the final block before the epilogue
4313 should be enough to verify that there is no edge to the exit
4314 block in CFG already. Calling make_edge in such case would
4315 cause us to mark that edge as fake and remove it later. */
4317 #ifdef ENABLE_CHECKING
4318 if (split_at_insn == BB_END (bb))
4320 e = find_edge (bb, EXIT_BLOCK_PTR);
4321 gcc_assert (e == NULL);
4325 /* Note that the following may create a new basic block
4326 and renumber the existing basic blocks. */
4327 if (split_at_insn != BB_END (bb))
4329 e = split_block (bb, split_at_insn);
4334 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
4337 if (insn == BB_HEAD (bb))
4343 verify_flow_info ();
4345 return blocks_split;
4348 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4349 the conditional branch target, SECOND_HEAD should be the fall-thru
4350 there is no need to handle this here the loop versioning code handles
4351 this. the reason for SECON_HEAD is that it is needed for condition
4352 in trees, and this should be of the same type since it is a hook. */
4354 rtl_lv_add_condition_to_bb (basic_block first_head ,
4355 basic_block second_head ATTRIBUTE_UNUSED,
4356 basic_block cond_bb, void *comp_rtx)
4358 rtx label, seq, jump;
4359 rtx op0 = XEXP ((rtx)comp_rtx, 0);
4360 rtx op1 = XEXP ((rtx)comp_rtx, 1);
4361 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
4362 enum machine_mode mode;
4365 label = block_label (first_head);
4366 mode = GET_MODE (op0);
4367 if (mode == VOIDmode)
4368 mode = GET_MODE (op1);
4371 op0 = force_operand (op0, NULL_RTX);
4372 op1 = force_operand (op1, NULL_RTX);
4373 do_compare_rtx_and_jump (op0, op1, comp, 0,
4374 mode, NULL_RTX, NULL_RTX, label, -1);
4375 jump = get_last_insn ();
4376 JUMP_LABEL (jump) = label;
4377 LABEL_NUSES (label)++;
4381 /* Add the new cond , in the new head. */
4382 emit_insn_after(seq, BB_END(cond_bb));
4386 /* Given a block B with unconditional branch at its end, get the
4387 store the return the branch edge and the fall-thru edge in
4388 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4390 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
4391 edge *fallthru_edge)
4393 edge e = EDGE_SUCC (b, 0);
4395 if (e->flags & EDGE_FALLTHRU)
4398 *branch_edge = EDGE_SUCC (b, 1);
4403 *fallthru_edge = EDGE_SUCC (b, 1);
4408 init_rtl_bb_info (basic_block bb)
4410 gcc_assert (!bb->il.x.rtl);
4411 bb->il.x.head_ = NULL;
4412 bb->il.x.rtl = ggc_alloc_cleared_rtl_bb_info ();
4415 /* Returns true if it is possible to remove edge E by redirecting
4416 it to the destination of the other edge from E->src. */
4419 rtl_can_remove_branch_p (const_edge e)
4421 const_basic_block src = e->src;
4422 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
4423 const_rtx insn = BB_END (src), set;
4425 /* The conditions are taken from try_redirect_by_replacing_jump. */
4426 if (target == EXIT_BLOCK_PTR)
4429 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
4432 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
4433 || BB_PARTITION (src) != BB_PARTITION (target))
4436 if (!onlyjump_p (insn)
4437 || tablejump_p (insn, NULL, NULL))
4440 set = single_set (insn);
4441 if (!set || side_effects_p (set))
4448 rtl_duplicate_bb (basic_block bb)
4450 bb = cfg_layout_duplicate_bb (bb);
4455 /* Implementation of CFG manipulation for linearized RTL. */
4456 struct cfg_hooks rtl_cfg_hooks = {
4458 rtl_verify_flow_info,
4460 rtl_create_basic_block,
4461 rtl_redirect_edge_and_branch,
4462 rtl_redirect_edge_and_branch_force,
4463 rtl_can_remove_branch_p,
4466 rtl_move_block_after,
4467 rtl_can_merge_blocks, /* can_merge_blocks_p */
4471 cfg_layout_can_duplicate_bb_p,
4474 rtl_make_forwarder_block,
4475 rtl_tidy_fallthru_edge,
4476 rtl_force_nonfallthru,
4477 rtl_block_ends_with_call_p,
4478 rtl_block_ends_with_condjump_p,
4479 rtl_flow_call_edges_add,
4480 NULL, /* execute_on_growing_pred */
4481 NULL, /* execute_on_shrinking_pred */
4482 NULL, /* duplicate loop for trees */
4483 NULL, /* lv_add_condition_to_bb */
4484 NULL, /* lv_adjust_loop_header_phi*/
4485 NULL, /* extract_cond_bb_edges */
4486 NULL, /* flush_pending_stmts */
4487 rtl_block_empty_p, /* block_empty_p */
4488 rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */
4491 /* Implementation of CFG manipulation for cfg layout RTL, where
4492 basic block connected via fallthru edges does not have to be adjacent.
4493 This representation will hopefully become the default one in future
4494 version of the compiler. */
4496 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
4498 rtl_verify_flow_info_1,
4500 cfg_layout_create_basic_block,
4501 cfg_layout_redirect_edge_and_branch,
4502 cfg_layout_redirect_edge_and_branch_force,
4503 rtl_can_remove_branch_p,
4504 cfg_layout_delete_block,
4505 cfg_layout_split_block,
4506 rtl_move_block_after,
4507 cfg_layout_can_merge_blocks_p,
4508 cfg_layout_merge_blocks,
4511 cfg_layout_can_duplicate_bb_p,
4512 cfg_layout_duplicate_bb,
4513 cfg_layout_split_edge,
4514 rtl_make_forwarder_block,
4515 NULL, /* tidy_fallthru_edge */
4516 rtl_force_nonfallthru,
4517 rtl_block_ends_with_call_p,
4518 rtl_block_ends_with_condjump_p,
4519 rtl_flow_call_edges_add,
4520 NULL, /* execute_on_growing_pred */
4521 NULL, /* execute_on_shrinking_pred */
4522 duplicate_loop_to_header_edge, /* duplicate loop for trees */
4523 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
4524 NULL, /* lv_adjust_loop_header_phi*/
4525 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
4526 NULL, /* flush_pending_stmts */
4527 rtl_block_empty_p, /* block_empty_p */
4528 rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */
4531 #include "gt-cfgrtl.h"