1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 2011, 2012 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
33 - CFG fixing after coarse manipulation
36 Functions not supposed for generic use:
37 - Infrastructure to determine quickly basic block for insn
38 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
39 - Edge redirection with updating and optimizing of insn chain
40 block_label, tidy_fallthru_edge, force_nonfallthru */
44 #include "coretypes.h"
47 #include "hard-reg-set.h"
48 #include "basic-block.h"
54 #include "rtl-error.h"
57 #include "insn-attr.h"
58 #include "insn-config.h"
59 #include "cfglayout.h"
62 #include "common/common-target.h"
65 #include "tree-pass.h"
68 static int can_delete_note_p (const_rtx
);
69 static int can_delete_label_p (const_rtx
);
70 static basic_block
rtl_split_edge (edge
);
71 static bool rtl_move_block_after (basic_block
, basic_block
);
72 static int rtl_verify_flow_info (void);
73 static basic_block
cfg_layout_split_block (basic_block
, void *);
74 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
75 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
76 static void cfg_layout_delete_block (basic_block
);
77 static void rtl_delete_block (basic_block
);
78 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
79 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
80 static basic_block
rtl_split_block (basic_block
, void *);
81 static void rtl_dump_bb (basic_block
, FILE *, int, int);
82 static int rtl_verify_flow_info_1 (void);
83 static void rtl_make_forwarder_block (edge
);
85 /* Return true if NOTE is not one of the ones that must be kept paired,
86 so that we may simply delete it. */
89 can_delete_note_p (const_rtx note
)
91 switch (NOTE_KIND (note
))
93 case NOTE_INSN_DELETED
:
94 case NOTE_INSN_BASIC_BLOCK
:
95 case NOTE_INSN_EPILOGUE_BEG
:
103 /* True if a given label can be deleted. */
106 can_delete_label_p (const_rtx label
)
108 return (!LABEL_PRESERVE_P (label
)
109 /* User declared labels must be preserved. */
110 && LABEL_NAME (label
) == 0
111 && !in_expr_list_p (forced_labels
, label
));
114 /* Delete INSN by patching it out. Return the next insn. */
117 delete_insn (rtx insn
)
119 rtx next
= NEXT_INSN (insn
);
121 bool really_delete
= true;
125 /* Some labels can't be directly removed from the INSN chain, as they
126 might be references via variables, constant pool etc.
127 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
128 if (! can_delete_label_p (insn
))
130 const char *name
= LABEL_NAME (insn
);
132 really_delete
= false;
133 PUT_CODE (insn
, NOTE
);
134 NOTE_KIND (insn
) = NOTE_INSN_DELETED_LABEL
;
135 NOTE_DELETED_LABEL_NAME (insn
) = name
;
138 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
143 /* If this insn has already been deleted, something is very wrong. */
144 gcc_assert (!INSN_DELETED_P (insn
));
146 INSN_DELETED_P (insn
) = 1;
149 /* If deleting a jump, decrement the use count of the label. Deleting
150 the label itself should happen in the normal course of block merging. */
153 if (JUMP_LABEL (insn
)
154 && LABEL_P (JUMP_LABEL (insn
)))
155 LABEL_NUSES (JUMP_LABEL (insn
))--;
157 /* If there are more targets, remove them too. */
159 = find_reg_note (insn
, REG_LABEL_TARGET
, NULL_RTX
)) != NULL_RTX
160 && LABEL_P (XEXP (note
, 0)))
162 LABEL_NUSES (XEXP (note
, 0))--;
163 remove_note (insn
, note
);
167 /* Also if deleting any insn that references a label as an operand. */
168 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, NULL_RTX
)) != NULL_RTX
169 && LABEL_P (XEXP (note
, 0)))
171 LABEL_NUSES (XEXP (note
, 0))--;
172 remove_note (insn
, note
);
175 if (JUMP_TABLE_DATA_P (insn
))
177 rtx pat
= PATTERN (insn
);
178 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
179 int len
= XVECLEN (pat
, diff_vec_p
);
182 for (i
= 0; i
< len
; i
++)
184 rtx label
= XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0);
186 /* When deleting code in bulk (e.g. removing many unreachable
187 blocks) we can delete a label that's a target of the vector
188 before deleting the vector itself. */
190 LABEL_NUSES (label
)--;
197 /* Like delete_insn but also purge dead edges from BB. */
200 delete_insn_and_edges (rtx insn
)
206 && BLOCK_FOR_INSN (insn
)
207 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
209 x
= delete_insn (insn
);
211 purge_dead_edges (BLOCK_FOR_INSN (insn
));
215 /* Unlink a chain of insns between START and FINISH, leaving notes
216 that must be paired. If CLEAR_BB is true, we set bb field for
217 insns that cannot be removed to NULL. */
220 delete_insn_chain (rtx start
, rtx finish
, bool clear_bb
)
224 /* Unchain the insns one by one. It would be quicker to delete all of these
225 with a single unchaining, rather than one at a time, but we need to keep
229 next
= NEXT_INSN (start
);
230 if (NOTE_P (start
) && !can_delete_note_p (start
))
233 next
= delete_insn (start
);
235 if (clear_bb
&& !INSN_DELETED_P (start
))
236 set_block_for_insn (start
, NULL
);
244 /* Create a new basic block consisting of the instructions between HEAD and END
245 inclusive. This function is designed to allow fast BB construction - reuses
246 the note and basic block struct in BB_NOTE, if any and do not grow
247 BASIC_BLOCK chain and should be used directly only by CFG construction code.
248 END can be NULL in to create new empty basic block before HEAD. Both END
249 and HEAD can be NULL to create basic block at the end of INSN chain.
250 AFTER is the basic block we should be put after. */
253 create_basic_block_structure (rtx head
, rtx end
, rtx bb_note
, basic_block after
)
258 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
261 /* If we found an existing note, thread it back onto the chain. */
269 after
= PREV_INSN (head
);
273 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
274 reorder_insns_nobb (bb_note
, bb_note
, after
);
278 /* Otherwise we must create a note and a basic block structure. */
282 init_rtl_bb_info (bb
);
285 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
286 else if (LABEL_P (head
) && end
)
288 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
294 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
300 NOTE_BASIC_BLOCK (bb_note
) = bb
;
303 /* Always include the bb note in the block. */
304 if (NEXT_INSN (end
) == bb_note
)
309 bb
->index
= last_basic_block
++;
310 bb
->flags
= BB_NEW
| BB_RTL
;
311 link_block (bb
, after
);
312 SET_BASIC_BLOCK (bb
->index
, bb
);
313 df_bb_refs_record (bb
->index
, false);
314 update_bb_for_insn (bb
);
315 BB_SET_PARTITION (bb
, BB_UNPARTITIONED
);
317 /* Tag the block so that we know it has been used when considering
318 other basic block notes. */
324 /* Create new basic block consisting of instructions in between HEAD and END
325 and place it to the BB chain after block AFTER. END can be NULL to
326 create a new empty basic block before HEAD. Both END and HEAD can be
327 NULL to create basic block at the end of INSN chain. */
330 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
332 rtx head
= (rtx
) headp
, end
= (rtx
) endp
;
335 /* Grow the basic block array if needed. */
336 if ((size_t) last_basic_block
>= VEC_length (basic_block
, basic_block_info
))
338 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
339 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, new_size
);
344 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
350 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
352 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
357 /* Delete the insns in a (non-live) block. We physically delete every
358 non-deleted-note insn, and update the flow graph appropriately.
360 Return nonzero if we deleted an exception handler. */
362 /* ??? Preserving all such notes strikes me as wrong. It would be nice
363 to post-process the stream to remove empty blocks, loops, ranges, etc. */
366 rtl_delete_block (basic_block b
)
370 /* If the head of this block is a CODE_LABEL, then it might be the
371 label for an exception handler which can't be reached. We need
372 to remove the label from the exception_handler_label list. */
375 end
= get_last_bb_insn (b
);
377 /* Selectively delete the entire chain. */
379 delete_insn_chain (insn
, end
, true);
383 fprintf (dump_file
, "deleting block %d\n", b
->index
);
384 df_bb_delete (b
->index
);
387 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
390 compute_bb_for_insn (void)
396 rtx end
= BB_END (bb
);
399 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
401 BLOCK_FOR_INSN (insn
) = bb
;
408 /* Release the basic_block_for_insn array. */
411 free_bb_for_insn (void)
414 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
415 if (!BARRIER_P (insn
))
416 BLOCK_FOR_INSN (insn
) = NULL
;
421 rest_of_pass_free_cfg (void)
424 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
425 valid at that point so it would be too late to call df_analyze. */
426 if (optimize
> 0 && flag_delayed_branch
)
428 df_note_add_problem ();
437 struct rtl_opt_pass pass_free_cfg
=
441 "*free_cfg", /* name */
443 rest_of_pass_free_cfg
, /* execute */
446 0, /* static_pass_number */
448 0, /* properties_required */
449 0, /* properties_provided */
450 PROP_cfg
, /* properties_destroyed */
451 0, /* todo_flags_start */
452 0, /* todo_flags_finish */
456 /* Return RTX to emit after when we want to emit code on the entry of function. */
458 entry_of_function (void)
460 return (n_basic_blocks
> NUM_FIXED_BLOCKS
?
461 BB_HEAD (ENTRY_BLOCK_PTR
->next_bb
) : get_insns ());
464 /* Emit INSN at the entry point of the function, ensuring that it is only
465 executed once per function. */
467 emit_insn_at_entry (rtx insn
)
469 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR
->succs
);
470 edge e
= ei_safe_edge (ei
);
471 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
473 insert_insn_on_edge (insn
, e
);
474 commit_edge_insertions ();
477 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
478 (or BARRIER if found) and notify df of the bb change.
479 The insn chain range is inclusive
480 (i.e. both BEGIN and END will be updated. */
483 update_bb_for_insn_chain (rtx begin
, rtx end
, basic_block bb
)
487 end
= NEXT_INSN (end
);
488 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
489 if (!BARRIER_P (insn
))
490 df_insn_change_bb (insn
, bb
);
493 /* Update BLOCK_FOR_INSN of insns in BB to BB,
494 and notify df of the change. */
497 update_bb_for_insn (basic_block bb
)
499 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
503 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
505 bb_note (basic_block bb
)
511 note
= NEXT_INSN (note
);
513 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note
));
517 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
518 note associated with the BLOCK. */
521 first_insn_after_basic_block_note (basic_block block
)
525 /* Get the first instruction in the block. */
526 insn
= BB_HEAD (block
);
528 if (insn
== NULL_RTX
)
531 insn
= NEXT_INSN (insn
);
532 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
534 return NEXT_INSN (insn
);
537 /* Creates a new basic block just after basic block B by splitting
538 everything after specified instruction I. */
541 rtl_split_block (basic_block bb
, void *insnp
)
544 rtx insn
= (rtx
) insnp
;
550 insn
= first_insn_after_basic_block_note (bb
);
556 insn
= PREV_INSN (insn
);
558 /* If the block contains only debug insns, insn would have
559 been NULL in a non-debug compilation, and then we'd end
560 up emitting a DELETED note. For -fcompare-debug
561 stability, emit the note too. */
562 if (insn
!= BB_END (bb
)
563 && DEBUG_INSN_P (next
)
564 && DEBUG_INSN_P (BB_END (bb
)))
566 while (next
!= BB_END (bb
) && DEBUG_INSN_P (next
))
567 next
= NEXT_INSN (next
);
569 if (next
== BB_END (bb
))
570 emit_note_after (NOTE_INSN_DELETED
, next
);
574 insn
= get_last_insn ();
577 /* We probably should check type of the insn so that we do not create
578 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
580 if (insn
== BB_END (bb
))
581 emit_note_after (NOTE_INSN_DELETED
, insn
);
583 /* Create the new basic block. */
584 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
585 BB_COPY_PARTITION (new_bb
, bb
);
588 /* Redirect the outgoing edges. */
589 new_bb
->succs
= bb
->succs
;
591 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
594 /* The new block starts off being dirty. */
595 df_set_bb_dirty (bb
);
599 /* Blocks A and B are to be merged into a single block A. The insns
600 are already contiguous. */
603 rtl_merge_blocks (basic_block a
, basic_block b
)
605 rtx b_head
= BB_HEAD (b
), b_end
= BB_END (b
), a_end
= BB_END (a
);
606 rtx del_first
= NULL_RTX
, del_last
= NULL_RTX
;
607 rtx b_debug_start
= b_end
, b_debug_end
= b_end
;
608 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
612 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
615 while (DEBUG_INSN_P (b_end
))
616 b_end
= PREV_INSN (b_debug_start
= b_end
);
618 /* If there was a CODE_LABEL beginning B, delete it. */
619 if (LABEL_P (b_head
))
621 /* Detect basic blocks with nothing but a label. This can happen
622 in particular at the end of a function. */
626 del_first
= del_last
= b_head
;
627 b_head
= NEXT_INSN (b_head
);
630 /* Delete the basic block note and handle blocks containing just that
632 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
640 b_head
= NEXT_INSN (b_head
);
643 /* If there was a jump out of A, delete it. */
648 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
650 || NOTE_INSN_BASIC_BLOCK_P (prev
)
651 || prev
== BB_HEAD (a
))
657 /* If this was a conditional jump, we need to also delete
658 the insn that set cc0. */
659 if (only_sets_cc0_p (prev
))
663 prev
= prev_nonnote_insn (prev
);
670 a_end
= PREV_INSN (del_first
);
672 else if (BARRIER_P (NEXT_INSN (a_end
)))
673 del_first
= NEXT_INSN (a_end
);
675 /* Delete everything marked above as well as crap that might be
676 hanging out between the two blocks. */
678 delete_insn_chain (del_first
, del_last
, true);
680 /* Reassociate the insns of B with A. */
683 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
687 else if (b_end
!= b_debug_end
)
689 /* Move any deleted labels and other notes between the end of A
690 and the debug insns that make up B after the debug insns,
691 bringing the debug insns into A while keeping the notes after
693 if (NEXT_INSN (a_end
) != b_debug_start
)
694 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
696 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
700 df_bb_delete (b
->index
);
703 /* If B was a forwarder block, propagate the locus on the edge. */
704 if (forwarder_p
&& !EDGE_SUCC (b
, 0)->goto_locus
)
705 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
708 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
712 /* Return true when block A and B can be merged. */
715 rtl_can_merge_blocks (basic_block a
, basic_block b
)
717 /* If we are partitioning hot/cold basic blocks, we don't want to
718 mess up unconditional or indirect jumps that cross between hot
721 Basic block partitioning may result in some jumps that appear to
722 be optimizable (or blocks that appear to be mergeable), but which really
723 must be left untouched (they are required to make it safely across
724 partition boundaries). See the comments at the top of
725 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
727 if (BB_PARTITION (a
) != BB_PARTITION (b
))
730 /* There must be exactly one edge in between the blocks. */
731 return (single_succ_p (a
)
732 && single_succ (a
) == b
735 /* Must be simple edge. */
736 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
738 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
739 /* If the jump insn has side effects,
740 we can't kill the edge. */
741 && (!JUMP_P (BB_END (a
))
743 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
746 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
750 block_label (basic_block block
)
752 if (block
== EXIT_BLOCK_PTR
)
755 if (!LABEL_P (BB_HEAD (block
)))
757 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
760 return BB_HEAD (block
);
763 /* Attempt to perform edge redirection by replacing possibly complex jump
764 instruction by unconditional jump or removing jump completely. This can
765 apply only if all edges now point to the same block. The parameters and
766 return values are equivalent to redirect_edge_and_branch. */
769 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
771 basic_block src
= e
->src
;
772 rtx insn
= BB_END (src
), kill_from
;
776 /* If we are partitioning hot/cold basic blocks, we don't want to
777 mess up unconditional or indirect jumps that cross between hot
780 Basic block partitioning may result in some jumps that appear to
781 be optimizable (or blocks that appear to be mergeable), but which really
782 must be left untouched (they are required to make it safely across
783 partition boundaries). See the comments at the top of
784 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
786 if (find_reg_note (insn
, REG_CROSSING_JUMP
, NULL_RTX
)
787 || BB_PARTITION (src
) != BB_PARTITION (target
))
790 /* We can replace or remove a complex jump only when we have exactly
791 two edges. Also, if we have exactly one outgoing edge, we can
793 if (EDGE_COUNT (src
->succs
) >= 3
794 /* Verify that all targets will be TARGET. Specifically, the
795 edge that is not E must also go to TARGET. */
796 || (EDGE_COUNT (src
->succs
) == 2
797 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
800 if (!onlyjump_p (insn
))
802 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
805 /* Avoid removing branch with side effects. */
806 set
= single_set (insn
);
807 if (!set
|| side_effects_p (set
))
810 /* In case we zap a conditional jump, we'll need to kill
811 the cc0 setter too. */
814 if (reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
815 && only_sets_cc0_p (PREV_INSN (insn
)))
816 kill_from
= PREV_INSN (insn
);
819 /* See if we can create the fallthru edge. */
820 if (in_cfglayout
|| can_fallthru (src
, target
))
823 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
826 /* Selectively unlink whole insn chain. */
829 rtx insn
= src
->il
.rtl
->footer
;
831 delete_insn_chain (kill_from
, BB_END (src
), false);
833 /* Remove barriers but keep jumptables. */
836 if (BARRIER_P (insn
))
838 if (PREV_INSN (insn
))
839 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
841 src
->il
.rtl
->footer
= NEXT_INSN (insn
);
842 if (NEXT_INSN (insn
))
843 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
847 insn
= NEXT_INSN (insn
);
851 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
855 /* If this already is simplejump, redirect it. */
856 else if (simplejump_p (insn
))
858 if (e
->dest
== target
)
861 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
862 INSN_UID (insn
), e
->dest
->index
, target
->index
);
863 if (!redirect_jump (insn
, block_label (target
), 0))
865 gcc_assert (target
== EXIT_BLOCK_PTR
);
870 /* Cannot do anything for target exit block. */
871 else if (target
== EXIT_BLOCK_PTR
)
874 /* Or replace possibly complicated jump insn by simple jump insn. */
877 rtx target_label
= block_label (target
);
878 rtx barrier
, label
, table
;
880 emit_jump_insn_after_noloc (gen_jump (target_label
), insn
);
881 JUMP_LABEL (BB_END (src
)) = target_label
;
882 LABEL_NUSES (target_label
)++;
884 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
885 INSN_UID (insn
), INSN_UID (BB_END (src
)));
888 delete_insn_chain (kill_from
, insn
, false);
890 /* Recognize a tablejump that we are converting to a
891 simple jump and remove its associated CODE_LABEL
892 and ADDR_VEC or ADDR_DIFF_VEC. */
893 if (tablejump_p (insn
, &label
, &table
))
894 delete_insn_chain (label
, table
, false);
896 barrier
= next_nonnote_insn (BB_END (src
));
897 if (!barrier
|| !BARRIER_P (barrier
))
898 emit_barrier_after (BB_END (src
));
901 if (barrier
!= NEXT_INSN (BB_END (src
)))
903 /* Move the jump before barrier so that the notes
904 which originally were or were created before jump table are
905 inside the basic block. */
906 rtx new_insn
= BB_END (src
);
908 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
909 PREV_INSN (barrier
), src
);
911 NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
912 PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
914 NEXT_INSN (new_insn
) = barrier
;
915 NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
917 PREV_INSN (new_insn
) = PREV_INSN (barrier
);
918 PREV_INSN (barrier
) = new_insn
;
923 /* Keep only one edge out and set proper flags. */
924 if (!single_succ_p (src
))
926 gcc_assert (single_succ_p (src
));
928 e
= single_succ_edge (src
);
930 e
->flags
= EDGE_FALLTHRU
;
934 e
->probability
= REG_BR_PROB_BASE
;
935 e
->count
= src
->count
;
937 if (e
->dest
!= target
)
938 redirect_edge_succ (e
, target
);
942 /* Subroutine of redirect_branch_edge that tries to patch the jump
943 instruction INSN so that it reaches block NEW. Do this
944 only when it originally reached block OLD. Return true if this
945 worked or the original target wasn't OLD, return false if redirection
949 patch_jump_insn (rtx insn
, rtx old_label
, basic_block new_bb
)
952 /* Recognize a tablejump and adjust all matching cases. */
953 if (tablejump_p (insn
, NULL
, &tmp
))
957 rtx new_label
= block_label (new_bb
);
959 if (new_bb
== EXIT_BLOCK_PTR
)
961 if (GET_CODE (PATTERN (tmp
)) == ADDR_VEC
)
962 vec
= XVEC (PATTERN (tmp
), 0);
964 vec
= XVEC (PATTERN (tmp
), 1);
966 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
967 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
969 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
970 --LABEL_NUSES (old_label
);
971 ++LABEL_NUSES (new_label
);
974 /* Handle casesi dispatch insns. */
975 if ((tmp
= single_set (insn
)) != NULL
976 && SET_DEST (tmp
) == pc_rtx
977 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
978 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
979 && XEXP (XEXP (SET_SRC (tmp
), 2), 0) == old_label
)
981 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
983 --LABEL_NUSES (old_label
);
984 ++LABEL_NUSES (new_label
);
987 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
989 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
992 if (new_bb
== EXIT_BLOCK_PTR
)
994 new_label
= block_label (new_bb
);
996 for (i
= 0; i
< n
; ++i
)
998 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
999 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
1000 if (XEXP (old_ref
, 0) == old_label
)
1002 ASM_OPERANDS_LABEL (tmp
, i
)
1003 = gen_rtx_LABEL_REF (Pmode
, new_label
);
1004 --LABEL_NUSES (old_label
);
1005 ++LABEL_NUSES (new_label
);
1009 if (JUMP_LABEL (insn
) == old_label
)
1011 JUMP_LABEL (insn
) = new_label
;
1012 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1014 remove_note (insn
, note
);
1018 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1020 remove_note (insn
, note
);
1021 if (JUMP_LABEL (insn
) != new_label
1022 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1023 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1025 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1027 XEXP (note
, 0) = new_label
;
1031 /* ?? We may play the games with moving the named labels from
1032 one basic block to the other in case only one computed_jump is
1034 if (computed_jump_p (insn
)
1035 /* A return instruction can't be redirected. */
1036 || returnjump_p (insn
))
1039 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1041 /* If the insn doesn't go where we think, we're confused. */
1042 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1044 /* If the substitution doesn't succeed, die. This can happen
1045 if the back end emitted unrecognizable instructions or if
1046 target is exit block on some arches. */
1047 if (!redirect_jump (insn
, block_label (new_bb
), 0))
1049 gcc_assert (new_bb
== EXIT_BLOCK_PTR
);
1058 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1061 redirect_branch_edge (edge e
, basic_block target
)
1063 rtx old_label
= BB_HEAD (e
->dest
);
1064 basic_block src
= e
->src
;
1065 rtx insn
= BB_END (src
);
1067 /* We can only redirect non-fallthru edges of jump insn. */
1068 if (e
->flags
& EDGE_FALLTHRU
)
1070 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1073 if (!currently_expanding_to_rtl
)
1075 if (!patch_jump_insn (insn
, old_label
, target
))
1079 /* When expanding this BB might actually contain multiple
1080 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1081 Redirect all of those that match our label. */
1082 FOR_BB_INSNS (src
, insn
)
1083 if (JUMP_P (insn
) && !patch_jump_insn (insn
, old_label
, target
))
1087 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1088 e
->src
->index
, e
->dest
->index
, target
->index
);
1090 if (e
->dest
!= target
)
1091 e
= redirect_edge_succ_nodup (e
, target
);
1096 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1097 expense of adding new instructions or reordering basic blocks.
1099 Function can be also called with edge destination equivalent to the TARGET.
1100 Then it should try the simplifications and do nothing if none is possible.
1102 Return edge representing the branch if transformation succeeded. Return NULL
1104 We still return NULL in case E already destinated TARGET and we didn't
1105 managed to simplify instruction stream. */
1108 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1111 basic_block src
= e
->src
;
1113 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1116 if (e
->dest
== target
)
1119 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1121 df_set_bb_dirty (src
);
1125 ret
= redirect_branch_edge (e
, target
);
1129 df_set_bb_dirty (src
);
1133 /* Like force_nonfallthru below, but additionally performs redirection
1134 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1135 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1136 simple_return_rtx, indicating which kind of returnjump to create.
1137 It should be NULL otherwise. */
1140 force_nonfallthru_and_redirect (edge e
, basic_block target
, rtx jump_label
)
1142 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1145 int abnormal_edge_flags
= 0;
1146 bool asm_goto_edge
= false;
1149 /* In the case the last instruction is conditional jump to the next
1150 instruction, first redirect the jump itself and then continue
1151 by creating a basic block afterwards to redirect fallthru edge. */
1152 if (e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
1153 && any_condjump_p (BB_END (e
->src
))
1154 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1157 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1160 redirected
= redirect_jump (BB_END (e
->src
), block_label (target
), 0);
1161 gcc_assert (redirected
);
1163 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1166 int prob
= INTVAL (XEXP (note
, 0));
1168 b
->probability
= prob
;
1169 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
1170 e
->probability
-= e
->probability
;
1171 e
->count
-= b
->count
;
1172 if (e
->probability
< 0)
1179 if (e
->flags
& EDGE_ABNORMAL
)
1181 /* Irritating special case - fallthru edge to the same block as abnormal
1183 We can't redirect abnormal edge, but we still can split the fallthru
1184 one and create separate abnormal edge to original destination.
1185 This allows bb-reorder to make such edge non-fallthru. */
1186 gcc_assert (e
->dest
== target
);
1187 abnormal_edge_flags
= e
->flags
& ~(EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
);
1188 e
->flags
&= EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
;
1192 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1193 if (e
->src
== ENTRY_BLOCK_PTR
)
1195 /* We can't redirect the entry block. Create an empty block
1196 at the start of the function which we use to add the new
1202 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
, ENTRY_BLOCK_PTR
);
1204 /* Change the existing edge's source to be the new block, and add
1205 a new edge from the entry block to the new block. */
1207 for (ei
= ei_start (ENTRY_BLOCK_PTR
->succs
); (tmp
= ei_safe_edge (ei
)); )
1211 VEC_unordered_remove (edge
, ENTRY_BLOCK_PTR
->succs
, ei
.index
);
1221 VEC_safe_push (edge
, gc
, bb
->succs
, e
);
1222 make_single_succ_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FALLTHRU
);
1226 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1227 don't point to the target or fallthru label. */
1228 if (JUMP_P (BB_END (e
->src
))
1229 && target
!= EXIT_BLOCK_PTR
1230 && (e
->flags
& EDGE_FALLTHRU
)
1231 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1233 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1234 bool adjust_jump_target
= false;
1236 for (i
= 0; i
< n
; ++i
)
1238 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1240 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1241 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1242 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1243 adjust_jump_target
= true;
1245 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1246 asm_goto_edge
= true;
1248 if (adjust_jump_target
)
1250 rtx insn
= BB_END (e
->src
), note
;
1251 rtx old_label
= BB_HEAD (e
->dest
);
1252 rtx new_label
= BB_HEAD (target
);
1254 if (JUMP_LABEL (insn
) == old_label
)
1256 JUMP_LABEL (insn
) = new_label
;
1257 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1259 remove_note (insn
, note
);
1263 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1265 remove_note (insn
, note
);
1266 if (JUMP_LABEL (insn
) != new_label
1267 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1268 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1270 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1272 XEXP (note
, 0) = new_label
;
1276 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1278 gcov_type count
= e
->count
;
1279 int probability
= e
->probability
;
1280 /* Create the new structures. */
1282 /* If the old block ended with a tablejump, skip its table
1283 by searching forward from there. Otherwise start searching
1284 forward from the last instruction of the old block. */
1285 if (!tablejump_p (BB_END (e
->src
), NULL
, ¬e
))
1286 note
= BB_END (e
->src
);
1287 note
= NEXT_INSN (note
);
1289 jump_block
= create_basic_block (note
, NULL
, e
->src
);
1290 jump_block
->count
= count
;
1291 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1292 jump_block
->loop_depth
= target
->loop_depth
;
1294 /* Make sure new block ends up in correct hot/cold section. */
1296 BB_COPY_PARTITION (jump_block
, e
->src
);
1297 if (flag_reorder_blocks_and_partition
1298 && targetm_common
.have_named_sections
1299 && JUMP_P (BB_END (jump_block
))
1300 && !any_condjump_p (BB_END (jump_block
))
1301 && (EDGE_SUCC (jump_block
, 0)->flags
& EDGE_CROSSING
))
1302 add_reg_note (BB_END (jump_block
), REG_CROSSING_JUMP
, NULL_RTX
);
1305 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1306 new_edge
->probability
= probability
;
1307 new_edge
->count
= count
;
1309 /* Redirect old edge. */
1310 redirect_edge_pred (e
, jump_block
);
1311 e
->probability
= REG_BR_PROB_BASE
;
1313 /* If asm goto has any label refs to target's label,
1314 add also edge from asm goto bb to target. */
1317 new_edge
->probability
/= 2;
1318 new_edge
->count
/= 2;
1319 jump_block
->count
/= 2;
1320 jump_block
->frequency
/= 2;
1321 new_edge
= make_edge (new_edge
->src
, target
,
1322 e
->flags
& ~EDGE_FALLTHRU
);
1323 new_edge
->probability
= probability
- probability
/ 2;
1324 new_edge
->count
= count
- count
/ 2;
1327 new_bb
= jump_block
;
1330 jump_block
= e
->src
;
1332 if (e
->goto_locus
&& e
->goto_block
== NULL
)
1333 loc
= e
->goto_locus
;
1336 e
->flags
&= ~EDGE_FALLTHRU
;
1337 if (target
== EXIT_BLOCK_PTR
)
1339 if (jump_label
== ret_rtx
)
1342 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block
), loc
);
1349 gcc_assert (jump_label
== simple_return_rtx
);
1350 #ifdef HAVE_simple_return
1351 emit_jump_insn_after_setloc (gen_simple_return (),
1352 BB_END (jump_block
), loc
);
1357 set_return_jump_label (BB_END (jump_block
));
1361 rtx label
= block_label (target
);
1362 emit_jump_insn_after_setloc (gen_jump (label
), BB_END (jump_block
), loc
);
1363 JUMP_LABEL (BB_END (jump_block
)) = label
;
1364 LABEL_NUSES (label
)++;
1367 emit_barrier_after (BB_END (jump_block
));
1368 redirect_edge_succ_nodup (e
, target
);
1370 if (abnormal_edge_flags
)
1371 make_edge (src
, target
, abnormal_edge_flags
);
1373 df_mark_solutions_dirty ();
1377 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1378 (and possibly create new basic block) to make edge non-fallthru.
1379 Return newly created BB or NULL if none. */
1382 rtl_force_nonfallthru (edge e
)
1384 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1387 /* Redirect edge even at the expense of creating new jump insn or
1388 basic block. Return new basic block if created, NULL otherwise.
1389 Conversion must be possible. */
1392 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1394 if (redirect_edge_and_branch (e
, target
)
1395 || e
->dest
== target
)
1398 /* In case the edge redirection failed, try to force it to be non-fallthru
1399 and redirect newly created simplejump. */
1400 df_set_bb_dirty (e
->src
);
1401 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1404 /* The given edge should potentially be a fallthru edge. If that is in
1405 fact true, delete the jump and barriers that are in the way. */
1408 rtl_tidy_fallthru_edge (edge e
)
1411 basic_block b
= e
->src
, c
= b
->next_bb
;
1413 /* ??? In a late-running flow pass, other folks may have deleted basic
1414 blocks by nopping out blocks, leaving multiple BARRIERs between here
1415 and the target label. They ought to be chastised and fixed.
1417 We can also wind up with a sequence of undeletable labels between
1418 one block and the next.
1420 So search through a sequence of barriers, labels, and notes for
1421 the head of block C and assert that we really do fall through. */
1423 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1427 /* Remove what will soon cease being the jump insn from the source block.
1428 If block B consisted only of this single jump, turn it into a deleted
1433 && (any_uncondjump_p (q
)
1434 || single_succ_p (b
)))
1437 /* If this was a conditional jump, we need to also delete
1438 the insn that set cc0. */
1439 if (any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1446 /* Selectively unlink the sequence. */
1447 if (q
!= PREV_INSN (BB_HEAD (c
)))
1448 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1450 e
->flags
|= EDGE_FALLTHRU
;
1453 /* Should move basic block BB after basic block AFTER. NIY. */
1456 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1457 basic_block after ATTRIBUTE_UNUSED
)
1462 /* Split a (typically critical) edge. Return the new block.
1463 The edge must not be abnormal.
1465 ??? The code generally expects to be called on critical edges.
1466 The case of a block ending in an unconditional jump to a
1467 block with multiple predecessors is not handled optimally. */
1470 rtl_split_edge (edge edge_in
)
1475 /* Abnormal edges cannot be split. */
1476 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1478 /* We are going to place the new block in front of edge destination.
1479 Avoid existence of fallthru predecessors. */
1480 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1482 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1485 force_nonfallthru (e
);
1488 /* Create the basic block note. */
1489 if (edge_in
->dest
!= EXIT_BLOCK_PTR
)
1490 before
= BB_HEAD (edge_in
->dest
);
1494 /* If this is a fall through edge to the exit block, the blocks might be
1495 not adjacent, and the right place is after the source. */
1496 if ((edge_in
->flags
& EDGE_FALLTHRU
) && edge_in
->dest
== EXIT_BLOCK_PTR
)
1498 before
= NEXT_INSN (BB_END (edge_in
->src
));
1499 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1500 BB_COPY_PARTITION (bb
, edge_in
->src
);
1504 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1505 /* ??? Why not edge_in->dest->prev_bb here? */
1506 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1509 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1511 /* For non-fallthru edges, we must adjust the predecessor's
1512 jump instruction to target our new block. */
1513 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1515 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1516 gcc_assert (redirected
);
1520 if (edge_in
->src
!= ENTRY_BLOCK_PTR
)
1522 /* For asm goto even splitting of fallthru edge might
1523 need insn patching, as other labels might point to the
1525 rtx last
= BB_END (edge_in
->src
);
1528 && edge_in
->dest
!= EXIT_BLOCK_PTR
1529 && extract_asm_operands (PATTERN (last
)) != NULL_RTX
1530 && patch_jump_insn (last
, before
, bb
))
1531 df_set_bb_dirty (edge_in
->src
);
1533 redirect_edge_succ (edge_in
, bb
);
1539 /* Queue instructions for insertion on an edge between two basic blocks.
1540 The new instructions and basic blocks (if any) will not appear in the
1541 CFG until commit_edge_insertions is called. */
1544 insert_insn_on_edge (rtx pattern
, edge e
)
1546 /* We cannot insert instructions on an abnormal critical edge.
1547 It will be easier to find the culprit if we die now. */
1548 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1550 if (e
->insns
.r
== NULL_RTX
)
1553 push_to_sequence (e
->insns
.r
);
1555 emit_insn (pattern
);
1557 e
->insns
.r
= get_insns ();
1561 /* Update the CFG for the instructions queued on edge E. */
1564 commit_one_edge_insertion (edge e
)
1566 rtx before
= NULL_RTX
, after
= NULL_RTX
, insns
, tmp
, last
;
1569 /* Pull the insns off the edge now since the edge might go away. */
1571 e
->insns
.r
= NULL_RTX
;
1573 /* Figure out where to put these insns. If the destination has
1574 one predecessor, insert there. Except for the exit block. */
1575 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR
)
1579 /* Get the location correct wrt a code label, and "nice" wrt
1580 a basic block note, and before everything else. */
1583 tmp
= NEXT_INSN (tmp
);
1584 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1585 tmp
= NEXT_INSN (tmp
);
1586 if (tmp
== BB_HEAD (bb
))
1589 after
= PREV_INSN (tmp
);
1591 after
= get_last_insn ();
1594 /* If the source has one successor and the edge is not abnormal,
1595 insert there. Except for the entry block. */
1596 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
1597 && single_succ_p (e
->src
)
1598 && e
->src
!= ENTRY_BLOCK_PTR
)
1602 /* It is possible to have a non-simple jump here. Consider a target
1603 where some forms of unconditional jumps clobber a register. This
1604 happens on the fr30 for example.
1606 We know this block has a single successor, so we can just emit
1607 the queued insns before the jump. */
1608 if (JUMP_P (BB_END (bb
)))
1609 before
= BB_END (bb
);
1612 /* We'd better be fallthru, or we've lost track of what's what. */
1613 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1615 after
= BB_END (bb
);
1619 /* Otherwise we must split the edge. */
1622 bb
= split_edge (e
);
1623 after
= BB_END (bb
);
1625 if (flag_reorder_blocks_and_partition
1626 && targetm_common
.have_named_sections
1627 && e
->src
!= ENTRY_BLOCK_PTR
1628 && BB_PARTITION (e
->src
) == BB_COLD_PARTITION
1629 && !(e
->flags
& EDGE_CROSSING
)
1631 && !any_condjump_p (after
)
1632 && (single_succ_edge (bb
)->flags
& EDGE_CROSSING
))
1633 add_reg_note (after
, REG_CROSSING_JUMP
, NULL_RTX
);
1636 /* Now that we've found the spot, do the insertion. */
1639 emit_insn_before_noloc (insns
, before
, bb
);
1640 last
= prev_nonnote_insn (before
);
1643 last
= emit_insn_after_noloc (insns
, after
, bb
);
1645 if (returnjump_p (last
))
1647 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1648 This is not currently a problem because this only happens
1649 for the (single) epilogue, which already has a fallthru edge
1652 e
= single_succ_edge (bb
);
1653 gcc_assert (e
->dest
== EXIT_BLOCK_PTR
1654 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
1656 e
->flags
&= ~EDGE_FALLTHRU
;
1657 emit_barrier_after (last
);
1660 delete_insn (before
);
1663 gcc_assert (!JUMP_P (last
));
1666 /* Update the CFG for all queued instructions. */
1669 commit_edge_insertions (void)
1673 #ifdef ENABLE_CHECKING
1674 verify_flow_info ();
1677 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1682 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1684 commit_one_edge_insertion (e
);
1689 /* Print out RTL-specific basic block information (live information
1690 at start and end). */
1693 rtl_dump_bb (basic_block bb
, FILE *outf
, int indent
, int flags ATTRIBUTE_UNUSED
)
1699 s_indent
= (char *) alloca ((size_t) indent
+ 1);
1700 memset (s_indent
, ' ', (size_t) indent
);
1701 s_indent
[indent
] = '\0';
1705 df_dump_top (bb
, outf
);
1709 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
1710 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
1711 insn
= NEXT_INSN (insn
))
1712 print_rtl_single (outf
, insn
);
1716 df_dump_bottom (bb
, outf
);
1722 /* Like print_rtl, but also print out live information for the start of each
1726 print_rtl_with_bb (FILE *outf
, const_rtx rtx_first
)
1730 fprintf (outf
, "(nil)\n");
1733 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
1734 int max_uid
= get_max_uid ();
1735 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
1736 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
1737 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
1742 df_dump_start (outf
);
1744 FOR_EACH_BB_REVERSE (bb
)
1748 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
1749 end
[INSN_UID (BB_END (bb
))] = bb
;
1750 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
1752 enum bb_state state
= IN_MULTIPLE_BB
;
1754 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
1756 in_bb_p
[INSN_UID (x
)] = state
;
1758 if (x
== BB_END (bb
))
1763 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
1767 bb
= start
[INSN_UID (tmp_rtx
)];
1769 dump_bb_info (bb
, true, false, dump_flags
, ";; ", outf
);
1771 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
1772 && !NOTE_P (tmp_rtx
)
1773 && !BARRIER_P (tmp_rtx
))
1774 fprintf (outf
, ";; Insn is not within a basic block\n");
1775 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
1776 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
1778 did_output
= print_rtl_single (outf
, tmp_rtx
);
1780 bb
= end
[INSN_UID (tmp_rtx
)];
1782 dump_bb_info (bb
, false, true, dump_flags
, ";; ", outf
);
1792 if (crtl
->epilogue_delay_list
!= 0)
1794 fprintf (outf
, "\n;; Insns in epilogue delay list:\n\n");
1795 for (tmp_rtx
= crtl
->epilogue_delay_list
; tmp_rtx
!= 0;
1796 tmp_rtx
= XEXP (tmp_rtx
, 1))
1797 print_rtl_single (outf
, XEXP (tmp_rtx
, 0));
1802 update_br_prob_note (basic_block bb
)
1805 if (!JUMP_P (BB_END (bb
)))
1807 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
1808 if (!note
|| INTVAL (XEXP (note
, 0)) == BRANCH_EDGE (bb
)->probability
)
1810 XEXP (note
, 0) = GEN_INT (BRANCH_EDGE (bb
)->probability
);
1813 /* Get the last insn associated with block BB (that includes barriers and
1814 tablejumps after BB). */
1816 get_last_bb_insn (basic_block bb
)
1819 rtx end
= BB_END (bb
);
1821 /* Include any jump table following the basic block. */
1822 if (tablejump_p (end
, NULL
, &tmp
))
1825 /* Include any barriers that may follow the basic block. */
1826 tmp
= next_nonnote_insn_bb (end
);
1827 while (tmp
&& BARRIER_P (tmp
))
1830 tmp
= next_nonnote_insn_bb (end
);
1836 /* Verify the CFG and RTL consistency common for both underlying RTL and
1839 Currently it does following checks:
1841 - overlapping of basic blocks
1842 - insns with wrong BLOCK_FOR_INSN pointers
1843 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1844 - tails of basic blocks (ensure that boundary is necessary)
1845 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1846 and NOTE_INSN_BASIC_BLOCK
1847 - verify that no fall_thru edge crosses hot/cold partition boundaries
1848 - verify that there are no pending RTL branch predictions
1850 In future it can be extended check a lot of other stuff as well
1851 (reachability of basic blocks, life information, etc. etc.). */
1854 rtl_verify_flow_info_1 (void)
1860 /* Check the general integrity of the basic blocks. */
1861 FOR_EACH_BB_REVERSE (bb
)
1865 if (!(bb
->flags
& BB_RTL
))
1867 error ("BB_RTL flag not set for block %d", bb
->index
);
1871 FOR_BB_INSNS (bb
, insn
)
1872 if (BLOCK_FOR_INSN (insn
) != bb
)
1874 error ("insn %d basic block pointer is %d, should be %d",
1876 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
1881 for (insn
= bb
->il
.rtl
->header
; insn
; insn
= NEXT_INSN (insn
))
1882 if (!BARRIER_P (insn
)
1883 && BLOCK_FOR_INSN (insn
) != NULL
)
1885 error ("insn %d in header of bb %d has non-NULL basic block",
1886 INSN_UID (insn
), bb
->index
);
1889 for (insn
= bb
->il
.rtl
->footer
; insn
; insn
= NEXT_INSN (insn
))
1890 if (!BARRIER_P (insn
)
1891 && BLOCK_FOR_INSN (insn
) != NULL
)
1893 error ("insn %d in footer of bb %d has non-NULL basic block",
1894 INSN_UID (insn
), bb
->index
);
1899 /* Now check the basic blocks (boundaries etc.) */
1900 FOR_EACH_BB_REVERSE (bb
)
1902 int n_fallthru
= 0, n_eh
= 0, n_call
= 0, n_abnormal
= 0, n_branch
= 0;
1903 edge e
, fallthru
= NULL
;
1907 if (JUMP_P (BB_END (bb
))
1908 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
1909 && EDGE_COUNT (bb
->succs
) >= 2
1910 && any_condjump_p (BB_END (bb
)))
1912 if (INTVAL (XEXP (note
, 0)) != BRANCH_EDGE (bb
)->probability
1913 && profile_status
!= PROFILE_ABSENT
)
1915 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1916 INTVAL (XEXP (note
, 0)), BRANCH_EDGE (bb
)->probability
);
1920 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1924 if (e
->flags
& EDGE_FALLTHRU
)
1925 n_fallthru
++, fallthru
= e
;
1927 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
1928 && e
->src
!= ENTRY_BLOCK_PTR
1929 && e
->dest
!= EXIT_BLOCK_PTR
);
1930 if (e
->flags
& EDGE_CROSSING
)
1934 error ("EDGE_CROSSING incorrectly set across same section");
1937 if (e
->flags
& EDGE_FALLTHRU
)
1939 error ("fallthru edge crosses section boundary (bb %i)",
1943 if (e
->flags
& EDGE_EH
)
1945 error ("EH edge crosses section boundary (bb %i)",
1950 else if (is_crossing
)
1952 error ("EDGE_CROSSING missing across section boundary");
1956 if ((e
->flags
& ~(EDGE_DFS_BACK
1958 | EDGE_IRREDUCIBLE_LOOP
1961 | EDGE_PRESERVE
)) == 0)
1964 if (e
->flags
& EDGE_ABNORMAL_CALL
)
1967 if (e
->flags
& EDGE_EH
)
1969 else if (e
->flags
& EDGE_ABNORMAL
)
1973 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
1975 error ("missing REG_EH_REGION note in the end of bb %i", bb
->index
);
1980 error ("too many eh edges %i", bb
->index
);
1984 && (!JUMP_P (BB_END (bb
))
1985 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
1986 || any_condjump_p (BB_END (bb
))))))
1988 error ("too many outgoing branch edges from bb %i", bb
->index
);
1991 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
1993 error ("fallthru edge after unconditional jump %i", bb
->index
);
1996 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
1998 error ("wrong number of branch edges after unconditional jump %i",
2002 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2003 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2005 error ("wrong amount of branch edges after conditional jump %i",
2009 if (n_call
&& !CALL_P (BB_END (bb
)))
2011 error ("call edges for non-call insn in bb %i", bb
->index
);
2015 && (!CALL_P (BB_END (bb
)) && n_call
!= n_abnormal
)
2016 && (!JUMP_P (BB_END (bb
))
2017 || any_condjump_p (BB_END (bb
))
2018 || any_uncondjump_p (BB_END (bb
))))
2020 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2024 for (x
= BB_HEAD (bb
); x
!= NEXT_INSN (BB_END (bb
)); x
= NEXT_INSN (x
))
2025 /* We may have a barrier inside a basic block before dead code
2026 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2027 if (!BARRIER_P (x
) && BLOCK_FOR_INSN (x
) != bb
)
2030 if (! BLOCK_FOR_INSN (x
))
2032 ("insn %d inside basic block %d but block_for_insn is NULL",
2033 INSN_UID (x
), bb
->index
);
2036 ("insn %d inside basic block %d but block_for_insn is %i",
2037 INSN_UID (x
), bb
->index
, BLOCK_FOR_INSN (x
)->index
);
2042 /* OK pointers are correct. Now check the header of basic
2043 block. It ought to contain optional CODE_LABEL followed
2044 by NOTE_BASIC_BLOCK. */
2048 if (BB_END (bb
) == x
)
2050 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2058 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2060 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2065 if (BB_END (bb
) == x
)
2066 /* Do checks for empty blocks here. */
2069 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2071 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2073 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2074 INSN_UID (x
), bb
->index
);
2078 if (x
== BB_END (bb
))
2081 if (control_flow_insn_p (x
))
2083 error ("in basic block %d:", bb
->index
);
2084 fatal_insn ("flow control insn inside a basic block", x
);
2093 /* Verify the CFG and RTL consistency common for both underlying RTL and
2096 Currently it does following checks:
2097 - all checks of rtl_verify_flow_info_1
2098 - test head/end pointers
2099 - check that all insns are in the basic blocks
2100 (except the switch handling code, barriers and notes)
2101 - check that all returns are followed by barriers
2102 - check that all fallthru edge points to the adjacent blocks. */
2105 rtl_verify_flow_info (void)
2108 int err
= rtl_verify_flow_info_1 ();
2110 rtx last_head
= get_last_insn ();
2111 basic_block
*bb_info
;
2113 const rtx rtx_first
= get_insns ();
2114 basic_block last_bb_seen
= ENTRY_BLOCK_PTR
, curr_bb
= NULL
;
2115 const int max_uid
= get_max_uid ();
2117 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2119 FOR_EACH_BB_REVERSE (bb
)
2122 rtx head
= BB_HEAD (bb
);
2123 rtx end
= BB_END (bb
);
2125 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2127 /* Verify the end of the basic block is in the INSN chain. */
2131 /* And that the code outside of basic blocks has NULL bb field. */
2133 && BLOCK_FOR_INSN (x
) != NULL
)
2135 error ("insn %d outside of basic blocks has non-NULL bb field",
2143 error ("end insn %d for block %d not found in the insn stream",
2144 INSN_UID (end
), bb
->index
);
2148 /* Work backwards from the end to the head of the basic block
2149 to verify the head is in the RTL chain. */
2150 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2152 /* While walking over the insn chain, verify insns appear
2153 in only one basic block. */
2154 if (bb_info
[INSN_UID (x
)] != NULL
)
2156 error ("insn %d is in multiple basic blocks (%d and %d)",
2157 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2161 bb_info
[INSN_UID (x
)] = bb
;
2168 error ("head insn %d for block %d not found in the insn stream",
2169 INSN_UID (head
), bb
->index
);
2173 last_head
= PREV_INSN (x
);
2175 e
= find_fallthru_edge (bb
->succs
);
2180 /* Ensure existence of barrier in BB with no fallthru edges. */
2181 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2183 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2185 error ("missing barrier after block %i", bb
->index
);
2189 if (BARRIER_P (insn
))
2193 else if (e
->src
!= ENTRY_BLOCK_PTR
2194 && e
->dest
!= EXIT_BLOCK_PTR
)
2198 if (e
->src
->next_bb
!= e
->dest
)
2201 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2202 e
->src
->index
, e
->dest
->index
);
2206 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2207 insn
= NEXT_INSN (insn
))
2208 if (BARRIER_P (insn
) || INSN_P (insn
))
2210 error ("verify_flow_info: Incorrect fallthru %i->%i",
2211 e
->src
->index
, e
->dest
->index
);
2212 fatal_insn ("wrong insn in the fallthru edge", insn
);
2218 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2220 /* Check that the code before the first basic block has NULL
2223 && BLOCK_FOR_INSN (x
) != NULL
)
2225 error ("insn %d outside of basic blocks has non-NULL bb field",
2233 last_bb_seen
= ENTRY_BLOCK_PTR
;
2235 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2237 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2239 bb
= NOTE_BASIC_BLOCK (x
);
2242 if (bb
!= last_bb_seen
->next_bb
)
2243 internal_error ("basic blocks not laid down consecutively");
2245 curr_bb
= last_bb_seen
= bb
;
2250 switch (GET_CODE (x
))
2257 /* An addr_vec is placed outside any basic block. */
2259 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2262 /* But in any case, non-deletable labels can appear anywhere. */
2266 fatal_insn ("insn outside basic block", x
);
2271 && returnjump_p (x
) && ! condjump_p (x
)
2272 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2273 fatal_insn ("return not followed by barrier", x
);
2274 if (curr_bb
&& x
== BB_END (curr_bb
))
2278 if (num_bb_notes
!= n_basic_blocks
- NUM_FIXED_BLOCKS
)
2280 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2281 num_bb_notes
, n_basic_blocks
);
2286 /* Assume that the preceding pass has possibly eliminated jump instructions
2287 or converted the unconditional jumps. Eliminate the edges from CFG.
2288 Return true if any edges are eliminated. */
2291 purge_dead_edges (basic_block bb
)
2294 rtx insn
= BB_END (bb
), note
;
2295 bool purged
= false;
2299 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
2301 insn
= PREV_INSN (insn
);
2302 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
2304 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2305 if (NONJUMP_INSN_P (insn
)
2306 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
2310 if (! may_trap_p (PATTERN (insn
))
2311 || ((eqnote
= find_reg_equal_equiv_note (insn
))
2312 && ! may_trap_p (XEXP (eqnote
, 0))))
2313 remove_note (insn
, note
);
2316 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2317 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2319 bool remove
= false;
2321 /* There are three types of edges we need to handle correctly here: EH
2322 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2323 latter can appear when nonlocal gotos are used. */
2324 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2328 else if (can_nonlocal_goto (insn
))
2330 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2332 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
2337 else if (e
->flags
& EDGE_EH
)
2338 remove
= !can_throw_internal (insn
);
2343 df_set_bb_dirty (bb
);
2356 /* We do care only about conditional jumps and simplejumps. */
2357 if (!any_condjump_p (insn
)
2358 && !returnjump_p (insn
)
2359 && !simplejump_p (insn
))
2362 /* Branch probability/prediction notes are defined only for
2363 condjumps. We've possibly turned condjump into simplejump. */
2364 if (simplejump_p (insn
))
2366 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2368 remove_note (insn
, note
);
2369 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
2370 remove_note (insn
, note
);
2373 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2375 /* Avoid abnormal flags to leak from computed jumps turned
2376 into simplejumps. */
2378 e
->flags
&= ~EDGE_ABNORMAL
;
2380 /* See if this edge is one we should keep. */
2381 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
2382 /* A conditional jump can fall through into the next
2383 block, so we should keep the edge. */
2388 else if (e
->dest
!= EXIT_BLOCK_PTR
2389 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
2390 /* If the destination block is the target of the jump,
2396 else if (e
->dest
== EXIT_BLOCK_PTR
&& returnjump_p (insn
))
2397 /* If the destination block is the exit block, and this
2398 instruction is a return, then keep the edge. */
2403 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2404 /* Keep the edges that correspond to exceptions thrown by
2405 this instruction and rematerialize the EDGE_ABNORMAL
2406 flag we just cleared above. */
2408 e
->flags
|= EDGE_ABNORMAL
;
2413 /* We do not need this edge. */
2414 df_set_bb_dirty (bb
);
2419 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
2423 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
2428 /* Redistribute probabilities. */
2429 if (single_succ_p (bb
))
2431 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
2432 single_succ_edge (bb
)->count
= bb
->count
;
2436 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2440 b
= BRANCH_EDGE (bb
);
2441 f
= FALLTHRU_EDGE (bb
);
2442 b
->probability
= INTVAL (XEXP (note
, 0));
2443 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
2444 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
2445 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
2450 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
2452 /* First, there should not be any EH or ABCALL edges resulting
2453 from non-local gotos and the like. If there were, we shouldn't
2454 have created the sibcall in the first place. Second, there
2455 should of course never have been a fallthru edge. */
2456 gcc_assert (single_succ_p (bb
));
2457 gcc_assert (single_succ_edge (bb
)->flags
2458 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
2463 /* If we don't see a jump insn, we don't know exactly why the block would
2464 have been broken at this point. Look for a simple, non-fallthru edge,
2465 as these are only created by conditional branches. If we find such an
2466 edge we know that there used to be a jump here and can then safely
2467 remove all non-fallthru edges. */
2469 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2470 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
2479 /* Remove all but the fake and fallthru edges. The fake edge may be
2480 the only successor for this block in the case of noreturn
2482 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2484 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
2486 df_set_bb_dirty (bb
);
2494 gcc_assert (single_succ_p (bb
));
2496 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
2497 single_succ_edge (bb
)->count
= bb
->count
;
2500 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
2505 /* Search all basic blocks for potentially dead edges and purge them. Return
2506 true if some edge has been eliminated. */
2509 purge_all_dead_edges (void)
2516 bool purged_here
= purge_dead_edges (bb
);
2518 purged
|= purged_here
;
2524 /* This is used by a few passes that emit some instructions after abnormal
2525 calls, moving the basic block's end, while they in fact do want to emit
2526 them on the fallthru edge. Look for abnormal call edges, find backward
2527 the call in the block and insert the instructions on the edge instead.
2529 Similarly, handle instructions throwing exceptions internally.
2531 Return true when instructions have been found and inserted on edges. */
2534 fixup_abnormal_edges (void)
2536 bool inserted
= false;
2544 /* Look for cases we are interested in - calls or instructions causing
2546 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2547 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
2548 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
2549 == (EDGE_ABNORMAL
| EDGE_EH
)))
2552 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
2556 /* Get past the new insns generated. Allow notes, as the insns
2557 may be already deleted. */
2559 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
2560 && !can_throw_internal (insn
)
2561 && insn
!= BB_HEAD (bb
))
2562 insn
= PREV_INSN (insn
);
2564 if (CALL_P (insn
) || can_throw_internal (insn
))
2568 e
= find_fallthru_edge (bb
->succs
);
2570 stop
= NEXT_INSN (BB_END (bb
));
2573 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
2575 next
= NEXT_INSN (insn
);
2580 /* Sometimes there's still the return value USE.
2581 If it's placed after a trapping call (i.e. that
2582 call is the last insn anyway), we have no fallthru
2583 edge. Simply delete this use and don't try to insert
2584 on the non-existent edge. */
2585 if (GET_CODE (PATTERN (insn
)) != USE
)
2587 /* We're not deleting it, we're moving it. */
2588 INSN_DELETED_P (insn
) = 0;
2589 PREV_INSN (insn
) = NULL_RTX
;
2590 NEXT_INSN (insn
) = NULL_RTX
;
2592 insert_insn_on_edge (insn
, e
);
2596 else if (!BARRIER_P (insn
))
2597 set_block_for_insn (insn
, NULL
);
2601 /* It may be that we don't find any trapping insn. In this
2602 case we discovered quite late that the insn that had been
2603 marked as can_throw_internal in fact couldn't trap at all.
2604 So we should in fact delete the EH edges out of the block. */
2606 purge_dead_edges (bb
);
2613 /* Same as split_block but update cfg_layout structures. */
2616 cfg_layout_split_block (basic_block bb
, void *insnp
)
2618 rtx insn
= (rtx
) insnp
;
2619 basic_block new_bb
= rtl_split_block (bb
, insn
);
2621 new_bb
->il
.rtl
->footer
= bb
->il
.rtl
->footer
;
2622 bb
->il
.rtl
->footer
= NULL
;
2627 /* Redirect Edge to DEST. */
2629 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
2631 basic_block src
= e
->src
;
2634 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
2637 if (e
->dest
== dest
)
2640 if (e
->src
!= ENTRY_BLOCK_PTR
2641 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
2643 df_set_bb_dirty (src
);
2647 if (e
->src
== ENTRY_BLOCK_PTR
2648 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
2651 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
2652 e
->src
->index
, dest
->index
);
2654 df_set_bb_dirty (e
->src
);
2655 redirect_edge_succ (e
, dest
);
2659 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2660 in the case the basic block appears to be in sequence. Avoid this
2663 if (e
->flags
& EDGE_FALLTHRU
)
2665 /* Redirect any branch edges unified with the fallthru one. */
2666 if (JUMP_P (BB_END (src
))
2667 && label_is_jump_target_p (BB_HEAD (e
->dest
),
2673 fprintf (dump_file
, "Fallthru edge unified with branch "
2674 "%i->%i redirected to %i\n",
2675 e
->src
->index
, e
->dest
->index
, dest
->index
);
2676 e
->flags
&= ~EDGE_FALLTHRU
;
2677 redirected
= redirect_branch_edge (e
, dest
);
2678 gcc_assert (redirected
);
2679 redirected
->flags
|= EDGE_FALLTHRU
;
2680 df_set_bb_dirty (redirected
->src
);
2683 /* In case we are redirecting fallthru edge to the branch edge
2684 of conditional jump, remove it. */
2685 if (EDGE_COUNT (src
->succs
) == 2)
2687 /* Find the edge that is different from E. */
2688 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
2691 && any_condjump_p (BB_END (src
))
2692 && onlyjump_p (BB_END (src
)))
2693 delete_insn (BB_END (src
));
2696 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
2697 e
->src
->index
, e
->dest
->index
, dest
->index
);
2698 ret
= redirect_edge_succ_nodup (e
, dest
);
2701 ret
= redirect_branch_edge (e
, dest
);
2703 /* We don't want simplejumps in the insn stream during cfglayout. */
2704 gcc_assert (!simplejump_p (BB_END (src
)));
2706 df_set_bb_dirty (src
);
2710 /* Simple wrapper as we always can redirect fallthru edges. */
2712 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
2714 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
2716 gcc_assert (redirected
);
2720 /* Same as delete_basic_block but update cfg_layout structures. */
2723 cfg_layout_delete_block (basic_block bb
)
2725 rtx insn
, next
, prev
= PREV_INSN (BB_HEAD (bb
)), *to
, remaints
;
2727 if (bb
->il
.rtl
->header
)
2729 next
= BB_HEAD (bb
);
2731 NEXT_INSN (prev
) = bb
->il
.rtl
->header
;
2733 set_first_insn (bb
->il
.rtl
->header
);
2734 PREV_INSN (bb
->il
.rtl
->header
) = prev
;
2735 insn
= bb
->il
.rtl
->header
;
2736 while (NEXT_INSN (insn
))
2737 insn
= NEXT_INSN (insn
);
2738 NEXT_INSN (insn
) = next
;
2739 PREV_INSN (next
) = insn
;
2741 next
= NEXT_INSN (BB_END (bb
));
2742 if (bb
->il
.rtl
->footer
)
2744 insn
= bb
->il
.rtl
->footer
;
2747 if (BARRIER_P (insn
))
2749 if (PREV_INSN (insn
))
2750 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2752 bb
->il
.rtl
->footer
= NEXT_INSN (insn
);
2753 if (NEXT_INSN (insn
))
2754 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2758 insn
= NEXT_INSN (insn
);
2760 if (bb
->il
.rtl
->footer
)
2763 NEXT_INSN (insn
) = bb
->il
.rtl
->footer
;
2764 PREV_INSN (bb
->il
.rtl
->footer
) = insn
;
2765 while (NEXT_INSN (insn
))
2766 insn
= NEXT_INSN (insn
);
2767 NEXT_INSN (insn
) = next
;
2769 PREV_INSN (next
) = insn
;
2771 set_last_insn (insn
);
2774 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2775 to
= &bb
->next_bb
->il
.rtl
->header
;
2777 to
= &cfg_layout_function_footer
;
2779 rtl_delete_block (bb
);
2782 prev
= NEXT_INSN (prev
);
2784 prev
= get_insns ();
2786 next
= PREV_INSN (next
);
2788 next
= get_last_insn ();
2790 if (next
&& NEXT_INSN (next
) != prev
)
2792 remaints
= unlink_insn_chain (prev
, next
);
2794 while (NEXT_INSN (insn
))
2795 insn
= NEXT_INSN (insn
);
2796 NEXT_INSN (insn
) = *to
;
2798 PREV_INSN (*to
) = insn
;
2803 /* Return true when blocks A and B can be safely merged. */
2806 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
2808 /* If we are partitioning hot/cold basic blocks, we don't want to
2809 mess up unconditional or indirect jumps that cross between hot
2812 Basic block partitioning may result in some jumps that appear to
2813 be optimizable (or blocks that appear to be mergeable), but which really
2814 must be left untouched (they are required to make it safely across
2815 partition boundaries). See the comments at the top of
2816 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2818 if (BB_PARTITION (a
) != BB_PARTITION (b
))
2821 /* If we would end up moving B's instructions, make sure it doesn't fall
2822 through into the exit block, since we cannot recover from a fallthrough
2823 edge into the exit block occurring in the middle of a function. */
2824 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
2826 edge e
= find_fallthru_edge (b
->succs
);
2827 if (e
&& e
->dest
== EXIT_BLOCK_PTR
)
2831 /* There must be exactly one edge in between the blocks. */
2832 return (single_succ_p (a
)
2833 && single_succ (a
) == b
2834 && single_pred_p (b
) == 1
2836 /* Must be simple edge. */
2837 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
2838 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
2839 /* If the jump insn has side effects, we can't kill the edge.
2840 When not optimizing, try_redirect_by_replacing_jump will
2841 not allow us to redirect an edge by replacing a table jump. */
2842 && (!JUMP_P (BB_END (a
))
2843 || ((!optimize
|| reload_completed
)
2844 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
2847 /* Merge block A and B. The blocks must be mergeable. */
2850 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
2852 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
2854 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
2857 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
2860 /* If there was a CODE_LABEL beginning B, delete it. */
2861 if (LABEL_P (BB_HEAD (b
)))
2863 delete_insn (BB_HEAD (b
));
2866 /* We should have fallthru edge in a, or we can do dummy redirection to get
2868 if (JUMP_P (BB_END (a
)))
2869 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
2870 gcc_assert (!JUMP_P (BB_END (a
)));
2872 /* When not optimizing and the edge is the only place in RTL which holds
2873 some unique locus, emit a nop with that locus in between. */
2874 if (!optimize
&& EDGE_SUCC (a
, 0)->goto_locus
)
2876 rtx insn
= BB_END (a
), end
= PREV_INSN (BB_HEAD (a
));
2877 int goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
2879 while (insn
!= end
&& (!INSN_P (insn
) || INSN_LOCATOR (insn
) == 0))
2880 insn
= PREV_INSN (insn
);
2881 if (insn
!= end
&& locator_eq (INSN_LOCATOR (insn
), goto_locus
))
2886 end
= NEXT_INSN (BB_END (b
));
2887 while (insn
!= end
&& !INSN_P (insn
))
2888 insn
= NEXT_INSN (insn
);
2889 if (insn
!= end
&& INSN_LOCATOR (insn
) != 0
2890 && locator_eq (INSN_LOCATOR (insn
), goto_locus
))
2895 BB_END (a
) = emit_insn_after_noloc (gen_nop (), BB_END (a
), a
);
2896 INSN_LOCATOR (BB_END (a
)) = goto_locus
;
2900 /* Possible line number notes should appear in between. */
2901 if (b
->il
.rtl
->header
)
2903 rtx first
= BB_END (a
), last
;
2905 last
= emit_insn_after_noloc (b
->il
.rtl
->header
, BB_END (a
), a
);
2906 /* The above might add a BARRIER as BB_END, but as barriers
2907 aren't valid parts of a bb, remove_insn doesn't update
2908 BB_END if it is a barrier. So adjust BB_END here. */
2909 while (BB_END (a
) != first
&& BARRIER_P (BB_END (a
)))
2910 BB_END (a
) = PREV_INSN (BB_END (a
));
2911 delete_insn_chain (NEXT_INSN (first
), last
, false);
2912 b
->il
.rtl
->header
= NULL
;
2915 /* In the case basic blocks are not adjacent, move them around. */
2916 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
2918 rtx first
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
2920 emit_insn_after_noloc (first
, BB_END (a
), a
);
2921 /* Skip possible DELETED_LABEL insn. */
2922 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2923 first
= NEXT_INSN (first
);
2924 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first
));
2927 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2928 We need to explicitly call. */
2929 update_bb_for_insn_chain (NEXT_INSN (first
),
2933 delete_insn (first
);
2935 /* Otherwise just re-associate the instructions. */
2940 update_bb_for_insn_chain (BB_HEAD (b
), BB_END (b
), a
);
2943 /* Skip possible DELETED_LABEL insn. */
2944 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2945 insn
= NEXT_INSN (insn
);
2946 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
2948 BB_END (a
) = BB_END (b
);
2952 df_bb_delete (b
->index
);
2954 /* Possible tablejumps and barriers should appear after the block. */
2955 if (b
->il
.rtl
->footer
)
2957 if (!a
->il
.rtl
->footer
)
2958 a
->il
.rtl
->footer
= b
->il
.rtl
->footer
;
2961 rtx last
= a
->il
.rtl
->footer
;
2963 while (NEXT_INSN (last
))
2964 last
= NEXT_INSN (last
);
2965 NEXT_INSN (last
) = b
->il
.rtl
->footer
;
2966 PREV_INSN (b
->il
.rtl
->footer
) = last
;
2968 b
->il
.rtl
->footer
= NULL
;
2971 /* If B was a forwarder block, propagate the locus on the edge. */
2972 if (forwarder_p
&& !EDGE_SUCC (b
, 0)->goto_locus
)
2973 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
2976 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
2982 cfg_layout_split_edge (edge e
)
2984 basic_block new_bb
=
2985 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR
2986 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
2989 if (e
->dest
== EXIT_BLOCK_PTR
)
2990 BB_COPY_PARTITION (new_bb
, e
->src
);
2992 BB_COPY_PARTITION (new_bb
, e
->dest
);
2993 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
2994 redirect_edge_and_branch_force (e
, new_bb
);
2999 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
3002 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
3006 /* Return 1 if BB ends with a call, possibly followed by some
3007 instructions that must stay with the call, 0 otherwise. */
3010 rtl_block_ends_with_call_p (basic_block bb
)
3012 rtx insn
= BB_END (bb
);
3014 while (!CALL_P (insn
)
3015 && insn
!= BB_HEAD (bb
)
3016 && (keep_with_call_p (insn
)
3018 || DEBUG_INSN_P (insn
)))
3019 insn
= PREV_INSN (insn
);
3020 return (CALL_P (insn
));
3023 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
3026 rtl_block_ends_with_condjump_p (const_basic_block bb
)
3028 return any_condjump_p (BB_END (bb
));
3031 /* Return true if we need to add fake edge to exit.
3032 Helper function for rtl_flow_call_edges_add. */
3035 need_fake_edge_p (const_rtx insn
)
3041 && !SIBLING_CALL_P (insn
)
3042 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
3043 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
3046 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
3047 && MEM_VOLATILE_P (PATTERN (insn
)))
3048 || (GET_CODE (PATTERN (insn
)) == PARALLEL
3049 && asm_noperands (insn
) != -1
3050 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
3051 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
3054 /* Add fake edges to the function exit for any non constant and non noreturn
3055 calls, volatile inline assembly in the bitmap of blocks specified by
3056 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
3059 The goal is to expose cases in which entering a basic block does not imply
3060 that all subsequent instructions must be executed. */
3063 rtl_flow_call_edges_add (sbitmap blocks
)
3066 int blocks_split
= 0;
3067 int last_bb
= last_basic_block
;
3068 bool check_last_block
= false;
3070 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
3074 check_last_block
= true;
3076 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
3078 /* In the last basic block, before epilogue generation, there will be
3079 a fallthru edge to EXIT. Special care is required if the last insn
3080 of the last basic block is a call because make_edge folds duplicate
3081 edges, which would result in the fallthru edge also being marked
3082 fake, which would result in the fallthru edge being removed by
3083 remove_fake_edges, which would result in an invalid CFG.
3085 Moreover, we can't elide the outgoing fake edge, since the block
3086 profiler needs to take this into account in order to solve the minimal
3087 spanning tree in the case that the call doesn't return.
3089 Handle this by adding a dummy instruction in a new last basic block. */
3090 if (check_last_block
)
3092 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
3093 rtx insn
= BB_END (bb
);
3095 /* Back up past insns that must be kept in the same block as a call. */
3096 while (insn
!= BB_HEAD (bb
)
3097 && keep_with_call_p (insn
))
3098 insn
= PREV_INSN (insn
);
3100 if (need_fake_edge_p (insn
))
3104 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
3107 insert_insn_on_edge (gen_use (const0_rtx
), e
);
3108 commit_edge_insertions ();
3113 /* Now add fake edges to the function exit for any non constant
3114 calls since there is no way that we can determine if they will
3117 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
3119 basic_block bb
= BASIC_BLOCK (i
);
3126 if (blocks
&& !TEST_BIT (blocks
, i
))
3129 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
3131 prev_insn
= PREV_INSN (insn
);
3132 if (need_fake_edge_p (insn
))
3135 rtx split_at_insn
= insn
;
3137 /* Don't split the block between a call and an insn that should
3138 remain in the same block as the call. */
3140 while (split_at_insn
!= BB_END (bb
)
3141 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
3142 split_at_insn
= NEXT_INSN (split_at_insn
);
3144 /* The handling above of the final block before the epilogue
3145 should be enough to verify that there is no edge to the exit
3146 block in CFG already. Calling make_edge in such case would
3147 cause us to mark that edge as fake and remove it later. */
3149 #ifdef ENABLE_CHECKING
3150 if (split_at_insn
== BB_END (bb
))
3152 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
3153 gcc_assert (e
== NULL
);
3157 /* Note that the following may create a new basic block
3158 and renumber the existing basic blocks. */
3159 if (split_at_insn
!= BB_END (bb
))
3161 e
= split_block (bb
, split_at_insn
);
3166 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
3169 if (insn
== BB_HEAD (bb
))
3175 verify_flow_info ();
3177 return blocks_split
;
3180 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
3181 the conditional branch target, SECOND_HEAD should be the fall-thru
3182 there is no need to handle this here the loop versioning code handles
3183 this. the reason for SECON_HEAD is that it is needed for condition
3184 in trees, and this should be of the same type since it is a hook. */
3186 rtl_lv_add_condition_to_bb (basic_block first_head
,
3187 basic_block second_head ATTRIBUTE_UNUSED
,
3188 basic_block cond_bb
, void *comp_rtx
)
3190 rtx label
, seq
, jump
;
3191 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
3192 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
3193 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
3194 enum machine_mode mode
;
3197 label
= block_label (first_head
);
3198 mode
= GET_MODE (op0
);
3199 if (mode
== VOIDmode
)
3200 mode
= GET_MODE (op1
);
3203 op0
= force_operand (op0
, NULL_RTX
);
3204 op1
= force_operand (op1
, NULL_RTX
);
3205 do_compare_rtx_and_jump (op0
, op1
, comp
, 0,
3206 mode
, NULL_RTX
, NULL_RTX
, label
, -1);
3207 jump
= get_last_insn ();
3208 JUMP_LABEL (jump
) = label
;
3209 LABEL_NUSES (label
)++;
3213 /* Add the new cond , in the new head. */
3214 emit_insn_after(seq
, BB_END(cond_bb
));
3218 /* Given a block B with unconditional branch at its end, get the
3219 store the return the branch edge and the fall-thru edge in
3220 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3222 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
3223 edge
*fallthru_edge
)
3225 edge e
= EDGE_SUCC (b
, 0);
3227 if (e
->flags
& EDGE_FALLTHRU
)
3230 *branch_edge
= EDGE_SUCC (b
, 1);
3235 *fallthru_edge
= EDGE_SUCC (b
, 1);
3240 init_rtl_bb_info (basic_block bb
)
3242 gcc_assert (!bb
->il
.rtl
);
3243 bb
->il
.rtl
= ggc_alloc_cleared_rtl_bb_info ();
3246 /* Returns true if it is possible to remove edge E by redirecting
3247 it to the destination of the other edge from E->src. */
3250 rtl_can_remove_branch_p (const_edge e
)
3252 const_basic_block src
= e
->src
;
3253 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
3254 const_rtx insn
= BB_END (src
), set
;
3256 /* The conditions are taken from try_redirect_by_replacing_jump. */
3257 if (target
== EXIT_BLOCK_PTR
)
3260 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3263 if (find_reg_note (insn
, REG_CROSSING_JUMP
, NULL_RTX
)
3264 || BB_PARTITION (src
) != BB_PARTITION (target
))
3267 if (!onlyjump_p (insn
)
3268 || tablejump_p (insn
, NULL
, NULL
))
3271 set
= single_set (insn
);
3272 if (!set
|| side_effects_p (set
))
3278 /* We do not want to declare these functions in a header file, since they
3279 should only be used through the cfghooks interface, and we do not want to
3280 move them here since it would require also moving quite a lot of related
3281 code. They are in cfglayout.c. */
3282 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block
);
3283 extern basic_block
cfg_layout_duplicate_bb (basic_block
);
3286 rtl_duplicate_bb (basic_block bb
)
3288 bb
= cfg_layout_duplicate_bb (bb
);
3293 /* Implementation of CFG manipulation for linearized RTL. */
3294 struct cfg_hooks rtl_cfg_hooks
= {
3296 rtl_verify_flow_info
,
3298 rtl_create_basic_block
,
3299 rtl_redirect_edge_and_branch
,
3300 rtl_redirect_edge_and_branch_force
,
3301 rtl_can_remove_branch_p
,
3304 rtl_move_block_after
,
3305 rtl_can_merge_blocks
, /* can_merge_blocks_p */
3309 cfg_layout_can_duplicate_bb_p
,
3312 rtl_make_forwarder_block
,
3313 rtl_tidy_fallthru_edge
,
3314 rtl_force_nonfallthru
,
3315 rtl_block_ends_with_call_p
,
3316 rtl_block_ends_with_condjump_p
,
3317 rtl_flow_call_edges_add
,
3318 NULL
, /* execute_on_growing_pred */
3319 NULL
, /* execute_on_shrinking_pred */
3320 NULL
, /* duplicate loop for trees */
3321 NULL
, /* lv_add_condition_to_bb */
3322 NULL
, /* lv_adjust_loop_header_phi*/
3323 NULL
, /* extract_cond_bb_edges */
3324 NULL
/* flush_pending_stmts */
3327 /* Implementation of CFG manipulation for cfg layout RTL, where
3328 basic block connected via fallthru edges does not have to be adjacent.
3329 This representation will hopefully become the default one in future
3330 version of the compiler. */
3332 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
3334 rtl_verify_flow_info_1
,
3336 cfg_layout_create_basic_block
,
3337 cfg_layout_redirect_edge_and_branch
,
3338 cfg_layout_redirect_edge_and_branch_force
,
3339 rtl_can_remove_branch_p
,
3340 cfg_layout_delete_block
,
3341 cfg_layout_split_block
,
3342 rtl_move_block_after
,
3343 cfg_layout_can_merge_blocks_p
,
3344 cfg_layout_merge_blocks
,
3347 cfg_layout_can_duplicate_bb_p
,
3348 cfg_layout_duplicate_bb
,
3349 cfg_layout_split_edge
,
3350 rtl_make_forwarder_block
,
3351 NULL
, /* tidy_fallthru_edge */
3352 rtl_force_nonfallthru
,
3353 rtl_block_ends_with_call_p
,
3354 rtl_block_ends_with_condjump_p
,
3355 rtl_flow_call_edges_add
,
3356 NULL
, /* execute_on_growing_pred */
3357 NULL
, /* execute_on_shrinking_pred */
3358 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
3359 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
3360 NULL
, /* lv_adjust_loop_header_phi*/
3361 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
3362 NULL
/* flush_pending_stmts */