1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
34 Functions not supposed for generic use:
35 - Infrastructure to determine quickly basic block for insn
36 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
37 - Edge redirection with updating and optimizing of insn chain
38 block_label, tidy_fallthru_edge, force_nonfallthru */
42 #include "coretypes.h"
46 #include "hard-reg-set.h"
47 #include "basic-block.h"
56 #include "insn-config.h"
57 #include "cfglayout.h"
61 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
62 /* ??? Should probably be using LABEL_NUSES instead. It would take a
63 bit of surgery to be able to use or co-opt the routines in jump. */
66 static int can_delete_note_p (rtx
);
67 static int can_delete_label_p (rtx
);
68 static void commit_one_edge_insertion (edge
, int);
69 static rtx
last_loop_beg_note (rtx
);
70 static bool back_edge_of_syntactic_loop_p (basic_block
, basic_block
);
71 basic_block
force_nonfallthru_and_redirect (edge
, basic_block
);
72 static basic_block
rtl_split_edge (edge
);
73 static bool rtl_move_block_after (basic_block
, basic_block
);
74 static int rtl_verify_flow_info (void);
75 static basic_block
cfg_layout_split_block (basic_block
, void *);
76 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
77 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
78 static void cfg_layout_delete_block (basic_block
);
79 static void rtl_delete_block (basic_block
);
80 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
81 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
82 static basic_block
rtl_split_block (basic_block
, void *);
83 static void rtl_dump_bb (basic_block
, FILE *, int);
84 static int rtl_verify_flow_info_1 (void);
85 static void mark_killed_regs (rtx
, rtx
, void *);
86 static void rtl_make_forwarder_block (edge
);
88 /* Return true if NOTE is not one of the ones that must be kept paired,
89 so that we may simply delete it. */
92 can_delete_note_p (rtx note
)
94 return (NOTE_LINE_NUMBER (note
) == NOTE_INSN_DELETED
95 || NOTE_LINE_NUMBER (note
) == NOTE_INSN_BASIC_BLOCK
96 || NOTE_LINE_NUMBER (note
) == NOTE_INSN_UNLIKELY_EXECUTED_CODE
97 || NOTE_LINE_NUMBER (note
) == NOTE_INSN_PREDICTION
);
100 /* True if a given label can be deleted. */
103 can_delete_label_p (rtx label
)
105 return (!LABEL_PRESERVE_P (label
)
106 /* User declared labels must be preserved. */
107 && LABEL_NAME (label
) == 0
108 && !in_expr_list_p (forced_labels
, label
)
109 && !in_expr_list_p (label_value_list
, label
));
112 /* Delete INSN by patching it out. Return the next insn. */
115 delete_insn (rtx insn
)
117 rtx next
= NEXT_INSN (insn
);
119 bool really_delete
= true;
123 /* Some labels can't be directly removed from the INSN chain, as they
124 might be references via variables, constant pool etc.
125 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
126 if (! can_delete_label_p (insn
))
128 const char *name
= LABEL_NAME (insn
);
130 really_delete
= false;
131 PUT_CODE (insn
, NOTE
);
132 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
133 NOTE_DELETED_LABEL_NAME (insn
) = name
;
136 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
141 /* If this insn has already been deleted, something is very wrong. */
142 if (INSN_DELETED_P (insn
))
145 INSN_DELETED_P (insn
) = 1;
148 /* If deleting a jump, decrement the use count of the label. Deleting
149 the label itself should happen in the normal course of block merging. */
152 && LABEL_P (JUMP_LABEL (insn
)))
153 LABEL_NUSES (JUMP_LABEL (insn
))--;
155 /* Also if deleting an insn that references a label. */
158 while ((note
= find_reg_note (insn
, REG_LABEL
, NULL_RTX
)) != NULL_RTX
159 && LABEL_P (XEXP (note
, 0)))
161 LABEL_NUSES (XEXP (note
, 0))--;
162 remove_note (insn
, note
);
167 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
168 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
170 rtx pat
= PATTERN (insn
);
171 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
172 int len
= XVECLEN (pat
, diff_vec_p
);
175 for (i
= 0; i
< len
; i
++)
177 rtx label
= XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0);
179 /* When deleting code in bulk (e.g. removing many unreachable
180 blocks) we can delete a label that's a target of the vector
181 before deleting the vector itself. */
183 LABEL_NUSES (label
)--;
190 /* Like delete_insn but also purge dead edges from BB. */
192 delete_insn_and_edges (rtx insn
)
198 && BLOCK_FOR_INSN (insn
)
199 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
201 x
= delete_insn (insn
);
203 purge_dead_edges (BLOCK_FOR_INSN (insn
));
207 /* Unlink a chain of insns between START and FINISH, leaving notes
208 that must be paired. */
211 delete_insn_chain (rtx start
, rtx finish
)
215 /* Unchain the insns one by one. It would be quicker to delete all of these
216 with a single unchaining, rather than one at a time, but we need to keep
220 next
= NEXT_INSN (start
);
221 if (NOTE_P (start
) && !can_delete_note_p (start
))
224 next
= delete_insn (start
);
232 /* Like delete_insn but also purge dead edges from BB. */
234 delete_insn_chain_and_edges (rtx first
, rtx last
)
239 && BLOCK_FOR_INSN (last
)
240 && BB_END (BLOCK_FOR_INSN (last
)) == last
)
242 delete_insn_chain (first
, last
);
244 purge_dead_edges (BLOCK_FOR_INSN (last
));
247 /* Create a new basic block consisting of the instructions between HEAD and END
248 inclusive. This function is designed to allow fast BB construction - reuses
249 the note and basic block struct in BB_NOTE, if any and do not grow
250 BASIC_BLOCK chain and should be used directly only by CFG construction code.
251 END can be NULL in to create new empty basic block before HEAD. Both END
252 and HEAD can be NULL to create basic block at the end of INSN chain.
253 AFTER is the basic block we should be put after. */
256 create_basic_block_structure (rtx head
, rtx end
, rtx bb_note
, basic_block after
)
261 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
264 /* If we found an existing note, thread it back onto the chain. */
272 after
= PREV_INSN (head
);
276 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
277 reorder_insns_nobb (bb_note
, bb_note
, after
);
281 /* Otherwise we must create a note and a basic block structure. */
287 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
288 else if (LABEL_P (head
) && end
)
290 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
296 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
302 NOTE_BASIC_BLOCK (bb_note
) = bb
;
305 /* Always include the bb note in the block. */
306 if (NEXT_INSN (end
) == bb_note
)
311 bb
->index
= last_basic_block
++;
313 link_block (bb
, after
);
314 BASIC_BLOCK (bb
->index
) = bb
;
315 update_bb_for_insn (bb
);
316 bb
->partition
= UNPARTITIONED
;
318 /* Tag the block so that we know it has been used when considering
319 other basic block notes. */
325 /* Create new basic block consisting of instructions in between HEAD and END
326 and place it to the BB chain after block AFTER. END can be NULL in to
327 create new empty basic block before HEAD. Both END and HEAD can be NULL to
328 create basic block at the end of INSN chain. */
331 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
333 rtx head
= headp
, end
= endp
;
336 /* Grow the basic block array if needed. */
337 if ((size_t) last_basic_block
>= VARRAY_SIZE (basic_block_info
))
339 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
340 VARRAY_GROW (basic_block_info
, new_size
);
345 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
351 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
353 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
355 initialize_bb_rbi (newbb
);
359 /* Delete the insns in a (non-live) block. We physically delete every
360 non-deleted-note insn, and update the flow graph appropriately.
362 Return nonzero if we deleted an exception handler. */
364 /* ??? Preserving all such notes strikes me as wrong. It would be nice
365 to post-process the stream to remove empty blocks, loops, ranges, etc. */
368 rtl_delete_block (basic_block b
)
372 /* If the head of this block is a CODE_LABEL, then it might be the
373 label for an exception handler which can't be reached.
375 We need to remove the label from the exception_handler_label list
376 and remove the associated NOTE_INSN_EH_REGION_BEG and
377 NOTE_INSN_EH_REGION_END notes. */
379 /* Get rid of all NOTE_INSN_PREDICTIONs and NOTE_INSN_LOOP_CONTs
380 hanging before the block. */
382 for (insn
= PREV_INSN (BB_HEAD (b
)); insn
; insn
= PREV_INSN (insn
))
386 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_PREDICTION
387 || NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_CONT
)
388 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
394 maybe_remove_eh_handler (insn
);
396 /* Include any jump table following the basic block. */
398 if (tablejump_p (end
, NULL
, &tmp
))
401 /* Include any barrier that may follow the basic block. */
402 tmp
= next_nonnote_insn (end
);
403 if (tmp
&& BARRIER_P (tmp
))
406 /* Selectively delete the entire chain. */
408 delete_insn_chain (insn
, end
);
411 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
414 compute_bb_for_insn (void)
420 rtx end
= BB_END (bb
);
423 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
425 BLOCK_FOR_INSN (insn
) = bb
;
432 /* Release the basic_block_for_insn array. */
435 free_bb_for_insn (void)
438 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
439 if (!BARRIER_P (insn
))
440 BLOCK_FOR_INSN (insn
) = NULL
;
443 /* Return RTX to emit after when we want to emit code on the entry of function. */
445 entry_of_function (void)
447 return (n_basic_blocks
? BB_HEAD (ENTRY_BLOCK_PTR
->next_bb
) : get_insns ());
450 /* Update insns block within BB. */
453 update_bb_for_insn (basic_block bb
)
457 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
459 if (!BARRIER_P (insn
))
460 set_block_for_insn (insn
, bb
);
461 if (insn
== BB_END (bb
))
466 /* Creates a new basic block just after basic block B by splitting
467 everything after specified instruction I. */
470 rtl_split_block (basic_block bb
, void *insnp
)
479 insn
= first_insn_after_basic_block_note (bb
);
482 insn
= PREV_INSN (insn
);
484 insn
= get_last_insn ();
487 /* We probably should check type of the insn so that we do not create
488 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
490 if (insn
== BB_END (bb
))
491 emit_note_after (NOTE_INSN_DELETED
, insn
);
493 /* Create the new basic block. */
494 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
497 /* Redirect the outgoing edges. */
498 new_bb
->succ
= bb
->succ
;
500 FOR_EACH_EDGE (e
, new_bb
->succ
, ix
)
503 if (bb
->global_live_at_start
)
505 new_bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
506 new_bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
507 COPY_REG_SET (new_bb
->global_live_at_end
, bb
->global_live_at_end
);
509 /* We now have to calculate which registers are live at the end
510 of the split basic block and at the start of the new basic
511 block. Start with those registers that are known to be live
512 at the end of the original basic block and get
513 propagate_block to determine which registers are live. */
514 COPY_REG_SET (new_bb
->global_live_at_start
, bb
->global_live_at_end
);
515 propagate_block (new_bb
, new_bb
->global_live_at_start
, NULL
, NULL
, 0);
516 COPY_REG_SET (bb
->global_live_at_end
,
517 new_bb
->global_live_at_start
);
518 #ifdef HAVE_conditional_execution
519 /* In the presence of conditional execution we are not able to update
520 liveness precisely. */
521 if (reload_completed
)
523 bb
->flags
|= BB_DIRTY
;
524 new_bb
->flags
|= BB_DIRTY
;
532 /* Blocks A and B are to be merged into a single block A. The insns
533 are already contiguous. */
536 rtl_merge_blocks (basic_block a
, basic_block b
)
538 rtx b_head
= BB_HEAD (b
), b_end
= BB_END (b
), a_end
= BB_END (a
);
539 rtx del_first
= NULL_RTX
, del_last
= NULL_RTX
;
542 /* If there was a CODE_LABEL beginning B, delete it. */
543 if (LABEL_P (b_head
))
545 /* Detect basic blocks with nothing but a label. This can happen
546 in particular at the end of a function. */
550 del_first
= del_last
= b_head
;
551 b_head
= NEXT_INSN (b_head
);
554 /* Delete the basic block note and handle blocks containing just that
556 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
564 b_head
= NEXT_INSN (b_head
);
567 /* If there was a jump out of A, delete it. */
572 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
574 || NOTE_LINE_NUMBER (prev
) == NOTE_INSN_BASIC_BLOCK
575 || prev
== BB_HEAD (a
))
581 /* If this was a conditional jump, we need to also delete
582 the insn that set cc0. */
583 if (only_sets_cc0_p (prev
))
587 prev
= prev_nonnote_insn (prev
);
594 a_end
= PREV_INSN (del_first
);
596 else if (BARRIER_P (NEXT_INSN (a_end
)))
597 del_first
= NEXT_INSN (a_end
);
599 /* Delete everything marked above as well as crap that might be
600 hanging out between the two blocks. */
602 delete_insn_chain (del_first
, del_last
);
604 /* Reassociate the insns of B with A. */
609 for (x
= a_end
; x
!= b_end
; x
= NEXT_INSN (x
))
610 set_block_for_insn (x
, a
);
612 set_block_for_insn (b_end
, a
);
620 /* Return true when block A and B can be merged. */
622 rtl_can_merge_blocks (basic_block a
, basic_block b
)
624 bool partitions_ok
= true;
626 /* If we are partitioning hot/cold basic blocks, we don't want to
627 mess up unconditional or indirect jumps that cross between hot
628 and cold sections. */
630 if (flag_reorder_blocks_and_partition
631 && (find_reg_note (BB_END (a
), REG_CROSSING_JUMP
, NULL_RTX
)
632 || find_reg_note (BB_END (b
), REG_CROSSING_JUMP
, NULL_RTX
)
633 || a
->partition
!= b
->partition
))
634 partitions_ok
= false;
636 /* There must be exactly one edge in between the blocks. */
637 return (EDGE_COUNT (a
->succ
) == 1
638 && EDGE_0 (a
->succ
)->dest
== b
639 && EDGE_COUNT (b
->pred
) == 1
641 /* Must be simple edge. */
642 && !(EDGE_0 (a
->succ
)->flags
& EDGE_COMPLEX
)
645 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
646 /* If the jump insn has side effects,
647 we can't kill the edge. */
648 && (!JUMP_P (BB_END (a
))
650 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
653 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
657 block_label (basic_block block
)
659 if (block
== EXIT_BLOCK_PTR
)
662 if (!LABEL_P (BB_HEAD (block
)))
664 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
667 return BB_HEAD (block
);
670 /* Attempt to perform edge redirection by replacing possibly complex jump
671 instruction by unconditional jump or removing jump completely. This can
672 apply only if all edges now point to the same block. The parameters and
673 return values are equivalent to redirect_edge_and_branch. */
676 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
678 basic_block src
= e
->src
;
679 rtx insn
= BB_END (src
), kill_from
;
685 /* If we are partitioning hot/cold basic blocks, we don't want to
686 mess up unconditional or indirect jumps that cross between hot
687 and cold sections. */
689 if (flag_reorder_blocks_and_partition
690 && find_reg_note (insn
, REG_CROSSING_JUMP
, NULL_RTX
))
693 /* Verify that all targets will be TARGET. */
694 FOR_EACH_EDGE (tmp
, src
->succ
, ix
)
695 if (tmp
->dest
!= target
&& tmp
!= e
)
698 if (tmp
|| !onlyjump_p (insn
))
700 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
703 /* Avoid removing branch with side effects. */
704 set
= single_set (insn
);
705 if (!set
|| side_effects_p (set
))
708 /* In case we zap a conditional jump, we'll need to kill
709 the cc0 setter too. */
712 if (reg_mentioned_p (cc0_rtx
, PATTERN (insn
)))
713 kill_from
= PREV_INSN (insn
);
716 /* See if we can create the fallthru edge. */
717 if (in_cfglayout
|| can_fallthru (src
, target
))
720 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
723 /* Selectively unlink whole insn chain. */
726 rtx insn
= src
->rbi
->footer
;
728 delete_insn_chain (kill_from
, BB_END (src
));
730 /* Remove barriers but keep jumptables. */
733 if (BARRIER_P (insn
))
735 if (PREV_INSN (insn
))
736 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
738 src
->rbi
->footer
= NEXT_INSN (insn
);
739 if (NEXT_INSN (insn
))
740 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
744 insn
= NEXT_INSN (insn
);
748 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)));
751 /* If this already is simplejump, redirect it. */
752 else if (simplejump_p (insn
))
754 if (e
->dest
== target
)
757 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
758 INSN_UID (insn
), e
->dest
->index
, target
->index
);
759 if (!redirect_jump (insn
, block_label (target
), 0))
761 if (target
== EXIT_BLOCK_PTR
)
767 /* Cannot do anything for target exit block. */
768 else if (target
== EXIT_BLOCK_PTR
)
771 /* Or replace possibly complicated jump insn by simple jump insn. */
774 rtx target_label
= block_label (target
);
775 rtx barrier
, label
, table
;
777 emit_jump_insn_after (gen_jump (target_label
), insn
);
778 JUMP_LABEL (BB_END (src
)) = target_label
;
779 LABEL_NUSES (target_label
)++;
781 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
782 INSN_UID (insn
), INSN_UID (BB_END (src
)));
785 delete_insn_chain (kill_from
, insn
);
787 /* Recognize a tablejump that we are converting to a
788 simple jump and remove its associated CODE_LABEL
789 and ADDR_VEC or ADDR_DIFF_VEC. */
790 if (tablejump_p (insn
, &label
, &table
))
791 delete_insn_chain (label
, table
);
793 barrier
= next_nonnote_insn (BB_END (src
));
794 if (!barrier
|| !BARRIER_P (barrier
))
795 emit_barrier_after (BB_END (src
));
798 if (barrier
!= NEXT_INSN (BB_END (src
)))
800 /* Move the jump before barrier so that the notes
801 which originally were or were created before jump table are
802 inside the basic block. */
803 rtx new_insn
= BB_END (src
);
806 for (tmp
= NEXT_INSN (BB_END (src
)); tmp
!= barrier
;
807 tmp
= NEXT_INSN (tmp
))
808 set_block_for_insn (tmp
, src
);
810 NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
811 PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
813 NEXT_INSN (new_insn
) = barrier
;
814 NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
816 PREV_INSN (new_insn
) = PREV_INSN (barrier
);
817 PREV_INSN (barrier
) = new_insn
;
822 /* Keep only one edge out and set proper flags. */
823 while (EDGE_COUNT (src
->succ
) > 1)
826 e
= EDGE_0 (src
->succ
);
828 e
->flags
= EDGE_FALLTHRU
;
832 e
->probability
= REG_BR_PROB_BASE
;
833 e
->count
= src
->count
;
835 /* We don't want a block to end on a line-number note since that has
836 the potential of changing the code between -g and not -g. */
837 while (NOTE_P (BB_END (e
->src
))
838 && NOTE_LINE_NUMBER (BB_END (e
->src
)) >= 0)
839 delete_insn (BB_END (e
->src
));
841 if (e
->dest
!= target
)
842 redirect_edge_succ (e
, target
);
847 /* Return last loop_beg note appearing after INSN, before start of next
848 basic block. Return INSN if there are no such notes.
850 When emitting jump to redirect a fallthru edge, it should always appear
851 after the LOOP_BEG notes, as loop optimizer expect loop to either start by
852 fallthru edge or jump following the LOOP_BEG note jumping to the loop exit
856 last_loop_beg_note (rtx insn
)
860 for (insn
= NEXT_INSN (insn
); insn
&& NOTE_P (insn
)
861 && NOTE_LINE_NUMBER (insn
) != NOTE_INSN_BASIC_BLOCK
;
862 insn
= NEXT_INSN (insn
))
863 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
869 /* Redirect edge representing branch of (un)conditional jump or tablejump,
872 redirect_branch_edge (edge e
, basic_block target
)
875 rtx old_label
= BB_HEAD (e
->dest
);
876 basic_block src
= e
->src
;
877 rtx insn
= BB_END (src
);
879 /* We can only redirect non-fallthru edges of jump insn. */
880 if (e
->flags
& EDGE_FALLTHRU
)
882 else if (!JUMP_P (insn
))
885 /* Recognize a tablejump and adjust all matching cases. */
886 if (tablejump_p (insn
, NULL
, &tmp
))
890 rtx new_label
= block_label (target
);
892 if (target
== EXIT_BLOCK_PTR
)
894 if (GET_CODE (PATTERN (tmp
)) == ADDR_VEC
)
895 vec
= XVEC (PATTERN (tmp
), 0);
897 vec
= XVEC (PATTERN (tmp
), 1);
899 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
900 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
902 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
903 --LABEL_NUSES (old_label
);
904 ++LABEL_NUSES (new_label
);
907 /* Handle casesi dispatch insns. */
908 if ((tmp
= single_set (insn
)) != NULL
909 && SET_DEST (tmp
) == pc_rtx
910 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
911 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
912 && XEXP (XEXP (SET_SRC (tmp
), 2), 0) == old_label
)
914 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (VOIDmode
,
916 --LABEL_NUSES (old_label
);
917 ++LABEL_NUSES (new_label
);
922 /* ?? We may play the games with moving the named labels from
923 one basic block to the other in case only one computed_jump is
925 if (computed_jump_p (insn
)
926 /* A return instruction can't be redirected. */
927 || returnjump_p (insn
))
930 /* If the insn doesn't go where we think, we're confused. */
931 if (JUMP_LABEL (insn
) != old_label
)
934 /* If the substitution doesn't succeed, die. This can happen
935 if the back end emitted unrecognizable instructions or if
936 target is exit block on some arches. */
937 if (!redirect_jump (insn
, block_label (target
), 0))
939 if (target
== EXIT_BLOCK_PTR
)
946 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
947 e
->src
->index
, e
->dest
->index
, target
->index
);
949 if (e
->dest
!= target
)
950 e
= redirect_edge_succ_nodup (e
, target
);
954 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
955 expense of adding new instructions or reordering basic blocks.
957 Function can be also called with edge destination equivalent to the TARGET.
958 Then it should try the simplifications and do nothing if none is possible.
960 Return edge representing the branch if transformation succeeded. Return NULL
962 We still return NULL in case E already destinated TARGET and we didn't
963 managed to simplify instruction stream. */
966 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
969 basic_block src
= e
->src
;
971 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
974 if (e
->dest
== target
)
977 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
979 src
->flags
|= BB_DIRTY
;
983 ret
= redirect_branch_edge (e
, target
);
987 src
->flags
|= BB_DIRTY
;
991 /* Like force_nonfallthru below, but additionally performs redirection
992 Used by redirect_edge_and_branch_force. */
995 force_nonfallthru_and_redirect (edge e
, basic_block target
)
997 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1000 int abnormal_edge_flags
= 0;
1002 /* In the case the last instruction is conditional jump to the next
1003 instruction, first redirect the jump itself and then continue
1004 by creating a basic block afterwards to redirect fallthru edge. */
1005 if (e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
1006 && any_condjump_p (BB_END (e
->src
))
1007 /* When called from cfglayout, fallthru edges do not
1008 necessarily go to the next block. */
1009 && e
->src
->next_bb
== e
->dest
1010 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1013 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1015 if (!redirect_jump (BB_END (e
->src
), block_label (target
), 0))
1017 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1020 int prob
= INTVAL (XEXP (note
, 0));
1022 b
->probability
= prob
;
1023 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
1024 e
->probability
-= e
->probability
;
1025 e
->count
-= b
->count
;
1026 if (e
->probability
< 0)
1033 if (e
->flags
& EDGE_ABNORMAL
)
1035 /* Irritating special case - fallthru edge to the same block as abnormal
1037 We can't redirect abnormal edge, but we still can split the fallthru
1038 one and create separate abnormal edge to original destination.
1039 This allows bb-reorder to make such edge non-fallthru. */
1040 if (e
->dest
!= target
)
1042 abnormal_edge_flags
= e
->flags
& ~(EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
);
1043 e
->flags
&= EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
;
1045 else if (!(e
->flags
& EDGE_FALLTHRU
))
1047 else if (e
->src
== ENTRY_BLOCK_PTR
)
1049 /* We can't redirect the entry block. Create an empty block at the
1050 start of the function which we use to add the new jump. */
1054 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
, ENTRY_BLOCK_PTR
);
1056 /* Change the existing edge's source to be the new block, and add
1057 a new edge from the entry block to the new block. */
1059 for (found
= false, ix
= 0; (tmp
= *(VEC_iterate(edge
, ENTRY_BLOCK_PTR
->succ
, ix
))); ix
++)
1062 VEC_ordered_remove (edge
, ENTRY_BLOCK_PTR
->succ
, ix
);
1070 VEC_safe_insert (edge
, bb
->succ
, 0, &e
);
1071 make_single_succ_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FALLTHRU
);
1074 if (EDGE_COUNT (e
->src
->succ
) >= 2 || abnormal_edge_flags
)
1076 /* Create the new structures. */
1078 /* If the old block ended with a tablejump, skip its table
1079 by searching forward from there. Otherwise start searching
1080 forward from the last instruction of the old block. */
1081 if (!tablejump_p (BB_END (e
->src
), NULL
, ¬e
))
1082 note
= BB_END (e
->src
);
1084 /* Position the new block correctly relative to loop notes. */
1085 note
= last_loop_beg_note (note
);
1086 note
= NEXT_INSN (note
);
1088 jump_block
= create_basic_block (note
, NULL
, e
->src
);
1089 jump_block
->count
= e
->count
;
1090 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1091 jump_block
->loop_depth
= target
->loop_depth
;
1093 if (target
->global_live_at_start
)
1095 jump_block
->global_live_at_start
1096 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1097 jump_block
->global_live_at_end
1098 = OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1099 COPY_REG_SET (jump_block
->global_live_at_start
,
1100 target
->global_live_at_start
);
1101 COPY_REG_SET (jump_block
->global_live_at_end
,
1102 target
->global_live_at_start
);
1105 /* Make sure new block ends up in correct hot/cold section. */
1107 jump_block
->partition
= e
->src
->partition
;
1108 if (flag_reorder_blocks_and_partition
)
1110 if (e
->src
->partition
== COLD_PARTITION
)
1112 rtx bb_note
, new_note
;
1113 for (bb_note
= BB_HEAD (jump_block
);
1114 bb_note
&& bb_note
!= NEXT_INSN (BB_END (jump_block
));
1115 bb_note
= NEXT_INSN (bb_note
))
1116 if (NOTE_P (bb_note
)
1117 && NOTE_LINE_NUMBER (bb_note
) == NOTE_INSN_BASIC_BLOCK
)
1119 new_note
= emit_note_after (NOTE_INSN_UNLIKELY_EXECUTED_CODE
,
1121 NOTE_BASIC_BLOCK (new_note
) = jump_block
;
1122 jump_block
->partition
= COLD_PARTITION
;
1124 if (JUMP_P (BB_END (jump_block
))
1125 && !any_condjump_p (BB_END (jump_block
))
1126 && EDGE_0 (jump_block
->succ
)->crossing_edge
)
1127 REG_NOTES (BB_END (jump_block
)) = gen_rtx_EXPR_LIST
1128 (REG_CROSSING_JUMP
, NULL_RTX
,
1129 REG_NOTES (BB_END (jump_block
)));
1133 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1134 new_edge
->probability
= e
->probability
;
1135 new_edge
->count
= e
->count
;
1137 /* Redirect old edge. */
1138 redirect_edge_pred (e
, jump_block
);
1139 e
->probability
= REG_BR_PROB_BASE
;
1141 new_bb
= jump_block
;
1144 jump_block
= e
->src
;
1146 e
->flags
&= ~EDGE_FALLTHRU
;
1147 if (target
== EXIT_BLOCK_PTR
)
1150 emit_jump_insn_after (gen_return (), BB_END (jump_block
));
1157 rtx label
= block_label (target
);
1158 emit_jump_insn_after (gen_jump (label
), BB_END (jump_block
));
1159 JUMP_LABEL (BB_END (jump_block
)) = label
;
1160 LABEL_NUSES (label
)++;
1163 emit_barrier_after (BB_END (jump_block
));
1164 redirect_edge_succ_nodup (e
, target
);
1166 if (abnormal_edge_flags
)
1167 make_edge (src
, target
, abnormal_edge_flags
);
1172 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1173 (and possibly create new basic block) to make edge non-fallthru.
1174 Return newly created BB or NULL if none. */
1177 force_nonfallthru (edge e
)
1179 return force_nonfallthru_and_redirect (e
, e
->dest
);
1182 /* Redirect edge even at the expense of creating new jump insn or
1183 basic block. Return new basic block if created, NULL otherwise.
1184 Abort if conversion is impossible. */
1187 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1189 if (redirect_edge_and_branch (e
, target
)
1190 || e
->dest
== target
)
1193 /* In case the edge redirection failed, try to force it to be non-fallthru
1194 and redirect newly created simplejump. */
1195 return force_nonfallthru_and_redirect (e
, target
);
1198 /* The given edge should potentially be a fallthru edge. If that is in
1199 fact true, delete the jump and barriers that are in the way. */
1202 rtl_tidy_fallthru_edge (edge e
)
1205 basic_block b
= e
->src
, c
= b
->next_bb
;
1209 FOR_EACH_EDGE (e2
, b
->succ
, ix
)
1213 /* ??? In a late-running flow pass, other folks may have deleted basic
1214 blocks by nopping out blocks, leaving multiple BARRIERs between here
1215 and the target label. They ought to be chastized and fixed.
1217 We can also wind up with a sequence of undeletable labels between
1218 one block and the next.
1220 So search through a sequence of barriers, labels, and notes for
1221 the head of block C and assert that we really do fall through. */
1223 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1227 /* Remove what will soon cease being the jump insn from the source block.
1228 If block B consisted only of this single jump, turn it into a deleted
1233 && (any_uncondjump_p (q
)
1234 /* FIXME: correct? */
1235 || (EDGE_0 (b
->succ
) == e
&& ix
== EDGE_COUNT (b
->succ
) - 1)))
1238 /* If this was a conditional jump, we need to also delete
1239 the insn that set cc0. */
1240 if (any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1246 /* We don't want a block to end on a line-number note since that has
1247 the potential of changing the code between -g and not -g. */
1248 while (NOTE_P (q
) && NOTE_LINE_NUMBER (q
) >= 0)
1252 /* Selectively unlink the sequence. */
1253 if (q
!= PREV_INSN (BB_HEAD (c
)))
1254 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)));
1256 e
->flags
|= EDGE_FALLTHRU
;
1259 /* Helper function for split_edge. Return true in case edge BB2 to BB1
1260 is back edge of syntactic loop. */
1263 back_edge_of_syntactic_loop_p (basic_block bb1
, basic_block bb2
)
1272 /* ??? Could we guarantee that bb indices are monotone, so that we could
1273 just compare them? */
1274 for (bb
= bb1
; bb
&& bb
!= bb2
; bb
= bb
->next_bb
)
1280 for (insn
= BB_END (bb1
); insn
!= BB_HEAD (bb2
) && count
>= 0;
1281 insn
= NEXT_INSN (insn
))
1284 if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_BEG
)
1286 else if (NOTE_LINE_NUMBER (insn
) == NOTE_INSN_LOOP_END
)
1293 /* Should move basic block BB after basic block AFTER. NIY. */
1296 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1297 basic_block after ATTRIBUTE_UNUSED
)
1302 /* Split a (typically critical) edge. Return the new block.
1303 Abort on abnormal edges.
1305 ??? The code generally expects to be called on critical edges.
1306 The case of a block ending in an unconditional jump to a
1307 block with multiple predecessors is not handled optimally. */
1310 rtl_split_edge (edge edge_in
)
1315 /* Abnormal edges cannot be split. */
1316 if ((edge_in
->flags
& EDGE_ABNORMAL
) != 0)
1319 /* We are going to place the new block in front of edge destination.
1320 Avoid existence of fallthru predecessors. */
1321 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1326 FOR_EACH_EDGE (e
, edge_in
->dest
->pred
, ix
)
1327 if (e
->flags
& EDGE_FALLTHRU
)
1331 force_nonfallthru (e
);
1334 /* Create the basic block note.
1336 Where we place the note can have a noticeable impact on the generated
1337 code. Consider this cfg:
1347 If we need to insert an insn on the edge from block 0 to block 1,
1348 we want to ensure the instructions we insert are outside of any
1349 loop notes that physically sit between block 0 and block 1. Otherwise
1350 we confuse the loop optimizer into thinking the loop is a phony. */
1352 if (edge_in
->dest
!= EXIT_BLOCK_PTR
1353 && PREV_INSN (BB_HEAD (edge_in
->dest
))
1354 && NOTE_P (PREV_INSN (BB_HEAD (edge_in
->dest
)))
1355 && (NOTE_LINE_NUMBER (PREV_INSN (BB_HEAD (edge_in
->dest
)))
1356 == NOTE_INSN_LOOP_BEG
)
1357 && !back_edge_of_syntactic_loop_p (edge_in
->dest
, edge_in
->src
))
1358 before
= PREV_INSN (BB_HEAD (edge_in
->dest
));
1359 else if (edge_in
->dest
!= EXIT_BLOCK_PTR
)
1360 before
= BB_HEAD (edge_in
->dest
);
1364 /* If this is a fall through edge to the exit block, the blocks might be
1365 not adjacent, and the right place is the after the source. */
1366 if (edge_in
->flags
& EDGE_FALLTHRU
&& edge_in
->dest
== EXIT_BLOCK_PTR
)
1368 before
= NEXT_INSN (BB_END (edge_in
->src
));
1371 && NOTE_LINE_NUMBER (before
) == NOTE_INSN_LOOP_END
)
1372 before
= NEXT_INSN (before
);
1373 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1376 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1378 /* ??? This info is likely going to be out of date very soon. */
1379 if (edge_in
->dest
->global_live_at_start
)
1381 bb
->global_live_at_start
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1382 bb
->global_live_at_end
= OBSTACK_ALLOC_REG_SET (&flow_obstack
);
1383 COPY_REG_SET (bb
->global_live_at_start
,
1384 edge_in
->dest
->global_live_at_start
);
1385 COPY_REG_SET (bb
->global_live_at_end
,
1386 edge_in
->dest
->global_live_at_start
);
1389 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1391 /* For non-fallthru edges, we must adjust the predecessor's
1392 jump instruction to target our new block. */
1393 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1395 if (!redirect_edge_and_branch (edge_in
, bb
))
1399 redirect_edge_succ (edge_in
, bb
);
1404 /* Queue instructions for insertion on an edge between two basic blocks.
1405 The new instructions and basic blocks (if any) will not appear in the
1406 CFG until commit_edge_insertions is called. */
1409 insert_insn_on_edge (rtx pattern
, edge e
)
1411 /* We cannot insert instructions on an abnormal critical edge.
1412 It will be easier to find the culprit if we die now. */
1413 if ((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
))
1416 if (e
->insns
.r
== NULL_RTX
)
1419 push_to_sequence (e
->insns
.r
);
1421 emit_insn (pattern
);
1423 e
->insns
.r
= get_insns ();
1427 /* Called from safe_insert_insn_on_edge through note_stores, marks live
1428 registers that are killed by the store. */
1430 mark_killed_regs (rtx reg
, rtx set ATTRIBUTE_UNUSED
, void *data
)
1432 regset killed
= data
;
1435 if (GET_CODE (reg
) == SUBREG
)
1436 reg
= SUBREG_REG (reg
);
1439 regno
= REGNO (reg
);
1440 if (regno
>= FIRST_PSEUDO_REGISTER
)
1441 SET_REGNO_REG_SET (killed
, regno
);
1444 for (i
= 0; i
< (int) hard_regno_nregs
[regno
][GET_MODE (reg
)]; i
++)
1445 SET_REGNO_REG_SET (killed
, regno
+ i
);
1449 /* Similar to insert_insn_on_edge, tries to put INSN to edge E. Additionally
1450 it checks whether this will not clobber the registers that are live on the
1451 edge (i.e. it requires liveness information to be up-to-date) and if there
1452 are some, then it tries to save and restore them. Returns true if
1455 safe_insert_insn_on_edge (rtx insn
, edge e
)
1458 regset_head killed_head
;
1459 regset killed
= INITIALIZE_REG_SET (killed_head
);
1460 rtx save_regs
= NULL_RTX
;
1461 int regno
, noccmode
;
1462 enum machine_mode mode
;
1464 #ifdef AVOID_CCMODE_COPIES
1470 for (x
= insn
; x
; x
= NEXT_INSN (x
))
1472 note_stores (PATTERN (x
), mark_killed_regs
, killed
);
1473 bitmap_operation (killed
, killed
, e
->dest
->global_live_at_start
,
1476 EXECUTE_IF_SET_IN_REG_SET (killed
, 0, regno
,
1478 mode
= regno
< FIRST_PSEUDO_REGISTER
1479 ? reg_raw_mode
[regno
]
1480 : GET_MODE (regno_reg_rtx
[regno
]);
1481 if (mode
== VOIDmode
)
1484 if (noccmode
&& mode
== CCmode
)
1487 save_regs
= alloc_EXPR_LIST (0,
1490 gen_raw_REG (mode
, regno
)),
1499 for (x
= save_regs
; x
; x
= XEXP (x
, 1))
1501 from
= XEXP (XEXP (x
, 0), 1);
1502 to
= XEXP (XEXP (x
, 0), 0);
1503 emit_move_insn (to
, from
);
1506 for (x
= save_regs
; x
; x
= XEXP (x
, 1))
1508 from
= XEXP (XEXP (x
, 0), 0);
1509 to
= XEXP (XEXP (x
, 0), 1);
1510 emit_move_insn (to
, from
);
1512 insn
= get_insns ();
1514 free_EXPR_LIST_list (&save_regs
);
1516 insert_insn_on_edge (insn
, e
);
1518 FREE_REG_SET (killed
);
1522 /* Update the CFG for the instructions queued on edge E. */
1525 commit_one_edge_insertion (edge e
, int watch_calls
)
1527 rtx before
= NULL_RTX
, after
= NULL_RTX
, insns
, tmp
, last
;
1528 basic_block bb
= NULL
;
1530 /* Pull the insns off the edge now since the edge might go away. */
1532 e
->insns
.r
= NULL_RTX
;
1534 /* Special case -- avoid inserting code between call and storing
1535 its return value. */
1536 if (watch_calls
&& (e
->flags
& EDGE_FALLTHRU
)
1537 && EDGE_COUNT (e
->dest
->pred
) == 1
1538 && e
->src
!= ENTRY_BLOCK_PTR
1539 && CALL_P (BB_END (e
->src
)))
1541 rtx next
= next_nonnote_insn (BB_END (e
->src
));
1543 after
= BB_HEAD (e
->dest
);
1544 /* The first insn after the call may be a stack pop, skip it. */
1546 && keep_with_call_p (next
))
1549 next
= next_nonnote_insn (next
);
1553 if (!before
&& !after
)
1555 /* Figure out where to put these things. If the destination has
1556 one predecessor, insert there. Except for the exit block. */
1557 if (EDGE_COUNT (e
->dest
->pred
) == 1 && e
->dest
!= EXIT_BLOCK_PTR
)
1561 /* Get the location correct wrt a code label, and "nice" wrt
1562 a basic block note, and before everything else. */
1565 tmp
= NEXT_INSN (tmp
);
1566 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1567 tmp
= NEXT_INSN (tmp
);
1570 && NOTE_LINE_NUMBER (tmp
) == NOTE_INSN_UNLIKELY_EXECUTED_CODE
)
1571 tmp
= NEXT_INSN (tmp
);
1572 if (tmp
== BB_HEAD (bb
))
1575 after
= PREV_INSN (tmp
);
1577 after
= get_last_insn ();
1580 /* If the source has one successor and the edge is not abnormal,
1581 insert there. Except for the entry block. */
1582 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
1583 && EDGE_COUNT (e
->src
->succ
) == 1
1584 && e
->src
!= ENTRY_BLOCK_PTR
)
1588 /* It is possible to have a non-simple jump here. Consider a target
1589 where some forms of unconditional jumps clobber a register. This
1590 happens on the fr30 for example.
1592 We know this block has a single successor, so we can just emit
1593 the queued insns before the jump. */
1594 if (JUMP_P (BB_END (bb
)))
1595 for (before
= BB_END (bb
);
1596 NOTE_P (PREV_INSN (before
))
1597 && NOTE_LINE_NUMBER (PREV_INSN (before
)) ==
1598 NOTE_INSN_LOOP_BEG
; before
= PREV_INSN (before
))
1602 /* We'd better be fallthru, or we've lost track of what's what. */
1603 if ((e
->flags
& EDGE_FALLTHRU
) == 0)
1606 after
= BB_END (bb
);
1609 /* Otherwise we must split the edge. */
1612 bb
= split_edge (e
);
1613 after
= BB_END (bb
);
1615 /* If we are partitioning hot/cold basic blocks, we must make sure
1616 that the new basic block ends up in the correct section. */
1618 bb
->partition
= e
->src
->partition
;
1619 if (flag_reorder_blocks_and_partition
1620 && e
->src
!= ENTRY_BLOCK_PTR
1621 && e
->src
->partition
== COLD_PARTITION
)
1623 rtx bb_note
, new_note
, cur_insn
;
1626 for (cur_insn
= BB_HEAD (bb
); cur_insn
!= NEXT_INSN (BB_END (bb
));
1627 cur_insn
= NEXT_INSN (cur_insn
))
1628 if (NOTE_P (cur_insn
)
1629 && NOTE_LINE_NUMBER (cur_insn
) == NOTE_INSN_BASIC_BLOCK
)
1635 new_note
= emit_note_after (NOTE_INSN_UNLIKELY_EXECUTED_CODE
,
1637 NOTE_BASIC_BLOCK (new_note
) = bb
;
1638 if (JUMP_P (BB_END (bb
))
1639 && !any_condjump_p (BB_END (bb
))
1640 && EDGE_0 (bb
->succ
)->crossing_edge
)
1641 REG_NOTES (BB_END (bb
)) = gen_rtx_EXPR_LIST
1642 (REG_CROSSING_JUMP
, NULL_RTX
, REG_NOTES (BB_END (bb
)));
1643 if (after
== bb_note
)
1649 /* Now that we've found the spot, do the insertion. */
1653 emit_insn_before (insns
, before
);
1654 last
= prev_nonnote_insn (before
);
1657 last
= emit_insn_after (insns
, after
);
1659 if (returnjump_p (last
))
1661 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1662 This is not currently a problem because this only happens
1663 for the (single) epilogue, which already has a fallthru edge
1666 e
= EDGE_0 (bb
->succ
);
1667 if (e
->dest
!= EXIT_BLOCK_PTR
1668 || EDGE_COUNT (bb
->succ
) > 1 || (e
->flags
& EDGE_FALLTHRU
) == 0)
1671 e
->flags
&= ~EDGE_FALLTHRU
;
1672 emit_barrier_after (last
);
1675 delete_insn (before
);
1677 else if (JUMP_P (last
))
1680 /* Mark the basic block for find_sub_basic_blocks. */
1684 /* Update the CFG for all queued instructions. */
1687 commit_edge_insertions (void)
1691 bool changed
= false;
1693 #ifdef ENABLE_CHECKING
1694 verify_flow_info ();
1697 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1702 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
1707 commit_one_edge_insertion (e
, false);
1715 blocks
= sbitmap_alloc (last_basic_block
);
1716 sbitmap_zero (blocks
);
1720 SET_BIT (blocks
, bb
->index
);
1721 /* Check for forgotten bb->aux values before commit_edge_insertions
1723 if (bb
->aux
!= &bb
->aux
)
1727 find_many_sub_basic_blocks (blocks
);
1728 sbitmap_free (blocks
);
1731 /* Update the CFG for all queued instructions, taking special care of inserting
1732 code on edges between call and storing its return value. */
1735 commit_edge_insertions_watch_calls (void)
1739 bool changed
= false;
1741 #ifdef ENABLE_CHECKING
1742 verify_flow_info ();
1745 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1750 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
1755 commit_one_edge_insertion (e
, true);
1763 blocks
= sbitmap_alloc (last_basic_block
);
1764 sbitmap_zero (blocks
);
1768 SET_BIT (blocks
, bb
->index
);
1769 /* Check for forgotten bb->aux values before commit_edge_insertions
1771 if (bb
->aux
!= &bb
->aux
)
1775 find_many_sub_basic_blocks (blocks
);
1776 sbitmap_free (blocks
);
1779 /* Print out RTL-specific basic block information (live information
1780 at start and end). */
1783 rtl_dump_bb (basic_block bb
, FILE *outf
, int indent
)
1789 s_indent
= alloca ((size_t) indent
+ 1);
1790 memset (s_indent
, ' ', (size_t) indent
);
1791 s_indent
[indent
] = '\0';
1793 fprintf (outf
, ";;%s Registers live at start: ", s_indent
);
1794 dump_regset (bb
->global_live_at_start
, outf
);
1797 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
1798 insn
= NEXT_INSN (insn
))
1799 print_rtl_single (outf
, insn
);
1801 fprintf (outf
, ";;%s Registers live at end: ", s_indent
);
1802 dump_regset (bb
->global_live_at_end
, outf
);
1806 /* Like print_rtl, but also print out live information for the start of each
1810 print_rtl_with_bb (FILE *outf
, rtx rtx_first
)
1815 fprintf (outf
, "(nil)\n");
1818 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
1819 int max_uid
= get_max_uid ();
1820 basic_block
*start
= xcalloc (max_uid
, sizeof (basic_block
));
1821 basic_block
*end
= xcalloc (max_uid
, sizeof (basic_block
));
1822 enum bb_state
*in_bb_p
= xcalloc (max_uid
, sizeof (enum bb_state
));
1826 FOR_EACH_BB_REVERSE (bb
)
1830 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
1831 end
[INSN_UID (BB_END (bb
))] = bb
;
1832 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
1834 enum bb_state state
= IN_MULTIPLE_BB
;
1836 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
1838 in_bb_p
[INSN_UID (x
)] = state
;
1840 if (x
== BB_END (bb
))
1845 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
1849 if ((bb
= start
[INSN_UID (tmp_rtx
)]) != NULL
)
1851 fprintf (outf
, ";; Start of basic block %d, registers live:",
1853 dump_regset (bb
->global_live_at_start
, outf
);
1857 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
1858 && !NOTE_P (tmp_rtx
)
1859 && !BARRIER_P (tmp_rtx
))
1860 fprintf (outf
, ";; Insn is not within a basic block\n");
1861 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
1862 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
1864 did_output
= print_rtl_single (outf
, tmp_rtx
);
1866 if ((bb
= end
[INSN_UID (tmp_rtx
)]) != NULL
)
1868 fprintf (outf
, ";; End of basic block %d, registers live:\n",
1870 dump_regset (bb
->global_live_at_end
, outf
);
1883 if (current_function_epilogue_delay_list
!= 0)
1885 fprintf (outf
, "\n;; Insns in epilogue delay list:\n\n");
1886 for (tmp_rtx
= current_function_epilogue_delay_list
; tmp_rtx
!= 0;
1887 tmp_rtx
= XEXP (tmp_rtx
, 1))
1888 print_rtl_single (outf
, XEXP (tmp_rtx
, 0));
1893 update_br_prob_note (basic_block bb
)
1896 if (!JUMP_P (BB_END (bb
)))
1898 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
1899 if (!note
|| INTVAL (XEXP (note
, 0)) == BRANCH_EDGE (bb
)->probability
)
1901 XEXP (note
, 0) = GEN_INT (BRANCH_EDGE (bb
)->probability
);
1904 /* Verify the CFG and RTL consistency common for both underlying RTL and
1907 Currently it does following checks:
1909 - test head/end pointers
1910 - overlapping of basic blocks
1911 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1912 - tails of basic blocks (ensure that boundary is necessary)
1913 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1914 and NOTE_INSN_BASIC_BLOCK
1915 - verify that no fall_thru edge crosses hot/cold partition boundaries
1917 In future it can be extended check a lot of other stuff as well
1918 (reachability of basic blocks, life information, etc. etc.). */
1921 rtl_verify_flow_info_1 (void)
1923 const int max_uid
= get_max_uid ();
1924 rtx last_head
= get_last_insn ();
1925 basic_block
*bb_info
;
1928 basic_block bb
, last_bb_seen
;
1930 bb_info
= xcalloc (max_uid
, sizeof (basic_block
));
1932 /* Check bb chain & numbers. */
1933 last_bb_seen
= ENTRY_BLOCK_PTR
;
1935 FOR_EACH_BB_REVERSE (bb
)
1937 rtx head
= BB_HEAD (bb
);
1938 rtx end
= BB_END (bb
);
1940 /* Verify the end of the basic block is in the INSN chain. */
1941 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
1947 error ("end insn %d for block %d not found in the insn stream",
1948 INSN_UID (end
), bb
->index
);
1952 /* Work backwards from the end to the head of the basic block
1953 to verify the head is in the RTL chain. */
1954 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
1956 /* While walking over the insn chain, verify insns appear
1957 in only one basic block and initialize the BB_INFO array
1958 used by other passes. */
1959 if (bb_info
[INSN_UID (x
)] != NULL
)
1961 error ("insn %d is in multiple basic blocks (%d and %d)",
1962 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
1966 bb_info
[INSN_UID (x
)] = bb
;
1973 error ("head insn %d for block %d not found in the insn stream",
1974 INSN_UID (head
), bb
->index
);
1981 /* Now check the basic blocks (boundaries etc.) */
1982 FOR_EACH_BB_REVERSE (bb
)
1984 int n_fallthru
= 0, n_eh
= 0, n_call
= 0, n_abnormal
= 0, n_branch
= 0;
1985 edge e
, fallthru
= NULL
;
1989 if (INSN_P (BB_END (bb
))
1990 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
1991 && EDGE_COUNT (bb
->succ
) >= 2
1992 && any_condjump_p (BB_END (bb
)))
1994 if (INTVAL (XEXP (note
, 0)) != BRANCH_EDGE (bb
)->probability
)
1996 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1997 INTVAL (XEXP (note
, 0)), BRANCH_EDGE (bb
)->probability
);
2001 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2003 if (e
->flags
& EDGE_FALLTHRU
)
2005 n_fallthru
++, fallthru
= e
;
2006 if (e
->crossing_edge
)
2008 error ("Fallthru edge crosses section boundary (bb %i)",
2014 if ((e
->flags
& ~(EDGE_DFS_BACK
2016 | EDGE_IRREDUCIBLE_LOOP
2017 | EDGE_LOOP_EXIT
)) == 0)
2020 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2023 if (e
->flags
& EDGE_EH
)
2025 else if (e
->flags
& EDGE_ABNORMAL
)
2029 if (n_eh
&& GET_CODE (PATTERN (BB_END (bb
))) != RESX
2030 && !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2032 error ("Missing REG_EH_REGION note in the end of bb %i", bb
->index
);
2036 && (!JUMP_P (BB_END (bb
))
2037 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2038 || any_condjump_p (BB_END (bb
))))))
2040 error ("Too many outgoing branch edges from bb %i", bb
->index
);
2043 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2045 error ("Fallthru edge after unconditional jump %i", bb
->index
);
2048 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2050 error ("Wrong amount of branch edges after unconditional jump %i", bb
->index
);
2053 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2054 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2056 error ("Wrong amount of branch edges after conditional jump %i", bb
->index
);
2059 if (n_call
&& !CALL_P (BB_END (bb
)))
2061 error ("Call edges for non-call insn in bb %i", bb
->index
);
2065 && (!CALL_P (BB_END (bb
)) && n_call
!= n_abnormal
)
2066 && (!JUMP_P (BB_END (bb
))
2067 || any_condjump_p (BB_END (bb
))
2068 || any_uncondjump_p (BB_END (bb
))))
2070 error ("Abnormal edges for no purpose in bb %i", bb
->index
);
2074 for (x
= BB_HEAD (bb
); x
!= NEXT_INSN (BB_END (bb
)); x
= NEXT_INSN (x
))
2075 if (BLOCK_FOR_INSN (x
) != bb
)
2078 if (! BLOCK_FOR_INSN (x
))
2080 ("insn %d inside basic block %d but block_for_insn is NULL",
2081 INSN_UID (x
), bb
->index
);
2084 ("insn %d inside basic block %d but block_for_insn is %i",
2085 INSN_UID (x
), bb
->index
, BLOCK_FOR_INSN (x
)->index
);
2090 /* OK pointers are correct. Now check the header of basic
2091 block. It ought to contain optional CODE_LABEL followed
2092 by NOTE_BASIC_BLOCK. */
2096 if (BB_END (bb
) == x
)
2098 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2106 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2108 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2113 if (BB_END (bb
) == x
)
2114 /* Do checks for empty blocks her. e */
2117 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2119 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2121 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2122 INSN_UID (x
), bb
->index
);
2126 if (x
== BB_END (bb
))
2129 if (control_flow_insn_p (x
))
2131 error ("in basic block %d:", bb
->index
);
2132 fatal_insn ("flow control insn inside a basic block", x
);
2142 /* Verify the CFG and RTL consistency common for both underlying RTL and
2145 Currently it does following checks:
2146 - all checks of rtl_verify_flow_info_1
2147 - check that all insns are in the basic blocks
2148 (except the switch handling code, barriers and notes)
2149 - check that all returns are followed by barriers
2150 - check that all fallthru edge points to the adjacent blocks. */
2152 rtl_verify_flow_info (void)
2155 int err
= rtl_verify_flow_info_1 ();
2158 const rtx rtx_first
= get_insns ();
2159 basic_block last_bb_seen
= ENTRY_BLOCK_PTR
, curr_bb
= NULL
;
2162 FOR_EACH_BB_REVERSE (bb
)
2165 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2166 if (e
->flags
& EDGE_FALLTHRU
)
2172 /* Ensure existence of barrier in BB with no fallthru edges. */
2173 for (insn
= BB_END (bb
); !insn
|| !BARRIER_P (insn
);
2174 insn
= NEXT_INSN (insn
))
2177 && NOTE_LINE_NUMBER (insn
) == NOTE_INSN_BASIC_BLOCK
))
2179 error ("missing barrier after block %i", bb
->index
);
2184 else if (e
->src
!= ENTRY_BLOCK_PTR
2185 && e
->dest
!= EXIT_BLOCK_PTR
)
2189 if (e
->src
->next_bb
!= e
->dest
)
2192 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2193 e
->src
->index
, e
->dest
->index
);
2197 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2198 insn
= NEXT_INSN (insn
))
2199 if (BARRIER_P (insn
)
2200 #ifndef CASE_DROPS_THROUGH
2203 || (INSN_P (insn
) && ! JUMP_TABLE_DATA_P (insn
))
2207 error ("verify_flow_info: Incorrect fallthru %i->%i",
2208 e
->src
->index
, e
->dest
->index
);
2209 fatal_insn ("wrong insn in the fallthru edge", insn
);
2216 last_bb_seen
= ENTRY_BLOCK_PTR
;
2218 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2220 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2222 bb
= NOTE_BASIC_BLOCK (x
);
2225 if (bb
!= last_bb_seen
->next_bb
)
2226 internal_error ("basic blocks not laid down consecutively");
2228 curr_bb
= last_bb_seen
= bb
;
2233 switch (GET_CODE (x
))
2240 /* An addr_vec is placed outside any basic block. */
2242 && JUMP_P (NEXT_INSN (x
))
2243 && (GET_CODE (PATTERN (NEXT_INSN (x
))) == ADDR_DIFF_VEC
2244 || GET_CODE (PATTERN (NEXT_INSN (x
))) == ADDR_VEC
))
2247 /* But in any case, non-deletable labels can appear anywhere. */
2251 fatal_insn ("insn outside basic block", x
);
2257 && returnjump_p (x
) && ! condjump_p (x
)
2258 && ! (NEXT_INSN (x
) && BARRIER_P (NEXT_INSN (x
))))
2259 fatal_insn ("return not followed by barrier", x
);
2260 if (curr_bb
&& x
== BB_END (curr_bb
))
2264 if (num_bb_notes
!= n_basic_blocks
)
2266 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2267 num_bb_notes
, n_basic_blocks
);
2272 /* Assume that the preceding pass has possibly eliminated jump instructions
2273 or converted the unconditional jumps. Eliminate the edges from CFG.
2274 Return true if any edges are eliminated. */
2277 purge_dead_edges (basic_block bb
)
2280 rtx insn
= BB_END (bb
), note
;
2281 bool purged
= false;
2285 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2286 if (NONJUMP_INSN_P (insn
)
2287 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
2291 if (! may_trap_p (PATTERN (insn
))
2292 || ((eqnote
= find_reg_equal_equiv_note (insn
))
2293 && ! may_trap_p (XEXP (eqnote
, 0))))
2294 remove_note (insn
, note
);
2297 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2298 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2300 if (e
->flags
& EDGE_EH
)
2302 if (can_throw_internal (BB_END (bb
)))
2305 else if (e
->flags
& EDGE_ABNORMAL_CALL
)
2307 if (CALL_P (BB_END (bb
))
2308 && (! (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
))
2309 || INTVAL (XEXP (note
, 0)) >= 0))
2316 bb
->flags
|= BB_DIRTY
;
2325 /* We do care only about conditional jumps and simplejumps. */
2326 if (!any_condjump_p (insn
)
2327 && !returnjump_p (insn
)
2328 && !simplejump_p (insn
))
2331 /* Branch probability/prediction notes are defined only for
2332 condjumps. We've possibly turned condjump into simplejump. */
2333 if (simplejump_p (insn
))
2335 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2337 remove_note (insn
, note
);
2338 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
2339 remove_note (insn
, note
);
2342 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2344 /* Avoid abnormal flags to leak from computed jumps turned
2345 into simplejumps. */
2347 e
->flags
&= ~EDGE_ABNORMAL
;
2349 /* See if this edge is one we should keep. */
2350 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
2351 /* A conditional jump can fall through into the next
2352 block, so we should keep the edge. */
2354 else if (e
->dest
!= EXIT_BLOCK_PTR
2355 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
2356 /* If the destination block is the target of the jump,
2359 else if (e
->dest
== EXIT_BLOCK_PTR
&& returnjump_p (insn
))
2360 /* If the destination block is the exit block, and this
2361 instruction is a return, then keep the edge. */
2363 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2364 /* Keep the edges that correspond to exceptions thrown by
2365 this instruction and rematerialize the EDGE_ABNORMAL
2366 flag we just cleared above. */
2368 e
->flags
|= EDGE_ABNORMAL
;
2372 /* We do not need this edge. */
2373 bb
->flags
|= BB_DIRTY
;
2380 if (EDGE_COUNT (bb
->succ
) == 0 || !purged
)
2384 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
2389 /* Redistribute probabilities. */
2390 if (EDGE_COUNT (bb
->succ
) == 1)
2392 EDGE_0 (bb
->succ
)->probability
= REG_BR_PROB_BASE
;
2393 EDGE_0 (bb
->succ
)->count
= bb
->count
;
2397 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2401 b
= BRANCH_EDGE (bb
);
2402 f
= FALLTHRU_EDGE (bb
);
2403 b
->probability
= INTVAL (XEXP (note
, 0));
2404 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
2405 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
2406 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
2411 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
2413 /* First, there should not be any EH or ABCALL edges resulting
2414 from non-local gotos and the like. If there were, we shouldn't
2415 have created the sibcall in the first place. Second, there
2416 should of course never have been a fallthru edge. */
2417 if (EDGE_COUNT (bb
->succ
) != 1)
2419 if (EDGE_0 (bb
->succ
)->flags
!= (EDGE_SIBCALL
| EDGE_ABNORMAL
))
2425 /* If we don't see a jump insn, we don't know exactly why the block would
2426 have been broken at this point. Look for a simple, non-fallthru edge,
2427 as these are only created by conditional branches. If we find such an
2428 edge we know that there used to be a jump here and can then safely
2429 remove all non-fallthru edges. */
2431 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2433 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
2442 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2444 if (!(e
->flags
& EDGE_FALLTHRU
))
2446 bb
->flags
|= BB_DIRTY
;
2453 if (EDGE_COUNT (bb
->succ
) != 1)
2456 EDGE_0 (bb
->succ
)->probability
= REG_BR_PROB_BASE
;
2457 EDGE_0 (bb
->succ
)->count
= bb
->count
;
2460 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
2465 /* Search all basic blocks for potentially dead edges and purge them. Return
2466 true if some edge has been eliminated. */
2469 purge_all_dead_edges (int update_life_p
)
2477 blocks
= sbitmap_alloc (last_basic_block
);
2478 sbitmap_zero (blocks
);
2483 bool purged_here
= purge_dead_edges (bb
);
2485 purged
|= purged_here
;
2486 if (purged_here
&& update_life_p
)
2487 SET_BIT (blocks
, bb
->index
);
2490 if (update_life_p
&& purged
)
2491 update_life_info (blocks
, UPDATE_LIFE_GLOBAL
,
2492 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2493 | PROP_KILL_DEAD_CODE
);
2496 sbitmap_free (blocks
);
2500 /* Same as split_block but update cfg_layout structures. */
2503 cfg_layout_split_block (basic_block bb
, void *insnp
)
2506 basic_block new_bb
= rtl_split_block (bb
, insn
);
2508 new_bb
->rbi
->footer
= bb
->rbi
->footer
;
2509 bb
->rbi
->footer
= NULL
;
2515 /* Redirect Edge to DEST. */
2517 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
2519 basic_block src
= e
->src
;
2522 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
2525 if (e
->dest
== dest
)
2528 if (e
->src
!= ENTRY_BLOCK_PTR
2529 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
2531 src
->flags
|= BB_DIRTY
;
2535 if (e
->src
== ENTRY_BLOCK_PTR
2536 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
2539 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
2540 e
->src
->index
, dest
->index
);
2542 e
->src
->flags
|= BB_DIRTY
;
2543 redirect_edge_succ (e
, dest
);
2547 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2548 in the case the basic block appears to be in sequence. Avoid this
2551 if (e
->flags
& EDGE_FALLTHRU
)
2553 /* Redirect any branch edges unified with the fallthru one. */
2554 if (JUMP_P (BB_END (src
))
2555 && label_is_jump_target_p (BB_HEAD (e
->dest
),
2559 fprintf (dump_file
, "Fallthru edge unified with branch "
2560 "%i->%i redirected to %i\n",
2561 e
->src
->index
, e
->dest
->index
, dest
->index
);
2562 e
->flags
&= ~EDGE_FALLTHRU
;
2563 if (!redirect_branch_edge (e
, dest
))
2565 e
->flags
|= EDGE_FALLTHRU
;
2566 e
->src
->flags
|= BB_DIRTY
;
2569 /* In case we are redirecting fallthru edge to the branch edge
2570 of conditional jump, remove it. */
2571 if (EDGE_COUNT (src
->succ
) == 2)
2577 FOR_EACH_EDGE (tmp
, src
->succ
, ix
)
2586 /* FIXME: Err, isn't this always EDGE_1? */
2587 if (EDGE_COUNT (src
->succ
) > (ix
+ 1))
2588 s
= EDGE_I (src
->succ
, ix
+ 1);
2590 s
= EDGE_0 (src
->succ
);
2593 && any_condjump_p (BB_END (src
))
2594 && onlyjump_p (BB_END (src
)))
2595 delete_insn (BB_END (src
));
2597 ret
= redirect_edge_succ_nodup (e
, dest
);
2599 fprintf (dump_file
, "Fallthru edge %i->%i redirected to %i\n",
2600 e
->src
->index
, e
->dest
->index
, dest
->index
);
2603 ret
= redirect_branch_edge (e
, dest
);
2605 /* We don't want simplejumps in the insn stream during cfglayout. */
2606 if (simplejump_p (BB_END (src
)))
2609 src
->flags
|= BB_DIRTY
;
2613 /* Simple wrapper as we always can redirect fallthru edges. */
2615 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
2617 if (!cfg_layout_redirect_edge_and_branch (e
, dest
))
2622 /* Same as delete_basic_block but update cfg_layout structures. */
2625 cfg_layout_delete_block (basic_block bb
)
2627 rtx insn
, next
, prev
= PREV_INSN (BB_HEAD (bb
)), *to
, remaints
;
2629 if (bb
->rbi
->header
)
2631 next
= BB_HEAD (bb
);
2633 NEXT_INSN (prev
) = bb
->rbi
->header
;
2635 set_first_insn (bb
->rbi
->header
);
2636 PREV_INSN (bb
->rbi
->header
) = prev
;
2637 insn
= bb
->rbi
->header
;
2638 while (NEXT_INSN (insn
))
2639 insn
= NEXT_INSN (insn
);
2640 NEXT_INSN (insn
) = next
;
2641 PREV_INSN (next
) = insn
;
2643 next
= NEXT_INSN (BB_END (bb
));
2644 if (bb
->rbi
->footer
)
2646 insn
= bb
->rbi
->footer
;
2649 if (BARRIER_P (insn
))
2651 if (PREV_INSN (insn
))
2652 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2654 bb
->rbi
->footer
= NEXT_INSN (insn
);
2655 if (NEXT_INSN (insn
))
2656 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2660 insn
= NEXT_INSN (insn
);
2662 if (bb
->rbi
->footer
)
2665 NEXT_INSN (insn
) = bb
->rbi
->footer
;
2666 PREV_INSN (bb
->rbi
->footer
) = insn
;
2667 while (NEXT_INSN (insn
))
2668 insn
= NEXT_INSN (insn
);
2669 NEXT_INSN (insn
) = next
;
2671 PREV_INSN (next
) = insn
;
2673 set_last_insn (insn
);
2676 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2677 to
= &bb
->next_bb
->rbi
->header
;
2679 to
= &cfg_layout_function_footer
;
2680 rtl_delete_block (bb
);
2683 prev
= NEXT_INSN (prev
);
2685 prev
= get_insns ();
2687 next
= PREV_INSN (next
);
2689 next
= get_last_insn ();
2691 if (next
&& NEXT_INSN (next
) != prev
)
2693 remaints
= unlink_insn_chain (prev
, next
);
2695 while (NEXT_INSN (insn
))
2696 insn
= NEXT_INSN (insn
);
2697 NEXT_INSN (insn
) = *to
;
2699 PREV_INSN (*to
) = insn
;
2704 /* Return true when blocks A and B can be safely merged. */
2706 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
2708 bool partitions_ok
= true;
2710 /* If we are partitioning hot/cold basic blocks, we don't want to
2711 mess up unconditional or indirect jumps that cross between hot
2712 and cold sections. */
2714 if (flag_reorder_blocks_and_partition
2715 && (find_reg_note (BB_END (a
), REG_CROSSING_JUMP
, NULL_RTX
)
2716 || find_reg_note (BB_END (b
), REG_CROSSING_JUMP
, NULL_RTX
)
2717 || a
->partition
!= b
->partition
))
2718 partitions_ok
= false;
2720 /* There must be exactly one edge in between the blocks. */
2721 return (EDGE_COUNT (a
->succ
) == 1
2722 && EDGE_0 (a
->succ
)->dest
== b
2723 && EDGE_COUNT (b
->pred
) == 1
2725 /* Must be simple edge. */
2726 && !(EDGE_0 (a
->succ
)->flags
& EDGE_COMPLEX
)
2728 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
2729 /* If the jump insn has side effects,
2730 we can't kill the edge. */
2731 && (!JUMP_P (BB_END (a
))
2732 || (reload_completed
2733 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
2736 /* Merge block A and B, abort when it is not possible. */
2738 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
2740 #ifdef ENABLE_CHECKING
2741 if (!cfg_layout_can_merge_blocks_p (a
, b
))
2745 /* If there was a CODE_LABEL beginning B, delete it. */
2746 if (LABEL_P (BB_HEAD (b
)))
2747 delete_insn (BB_HEAD (b
));
2749 /* We should have fallthru edge in a, or we can do dummy redirection to get
2751 if (JUMP_P (BB_END (a
)))
2752 try_redirect_by_replacing_jump (EDGE_0 (a
->succ
), b
, true);
2753 if (JUMP_P (BB_END (a
)))
2756 /* Possible line number notes should appear in between. */
2759 rtx first
= BB_END (a
), last
;
2761 last
= emit_insn_after (b
->rbi
->header
, BB_END (a
));
2762 delete_insn_chain (NEXT_INSN (first
), last
);
2763 b
->rbi
->header
= NULL
;
2766 /* In the case basic blocks are not adjacent, move them around. */
2767 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
2769 rtx first
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
2771 emit_insn_after (first
, BB_END (a
));
2772 /* Skip possible DELETED_LABEL insn. */
2773 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2774 first
= NEXT_INSN (first
);
2775 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2778 delete_insn (first
);
2780 /* Otherwise just re-associate the instructions. */
2785 for (insn
= BB_HEAD (b
);
2786 insn
!= NEXT_INSN (BB_END (b
));
2787 insn
= NEXT_INSN (insn
))
2788 set_block_for_insn (insn
, a
);
2790 /* Skip possible DELETED_LABEL insn. */
2791 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2792 insn
= NEXT_INSN (insn
);
2793 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2796 BB_END (a
) = BB_END (b
);
2800 /* Possible tablejumps and barriers should appear after the block. */
2803 if (!a
->rbi
->footer
)
2804 a
->rbi
->footer
= b
->rbi
->footer
;
2807 rtx last
= a
->rbi
->footer
;
2809 while (NEXT_INSN (last
))
2810 last
= NEXT_INSN (last
);
2811 NEXT_INSN (last
) = b
->rbi
->footer
;
2812 PREV_INSN (b
->rbi
->footer
) = last
;
2814 b
->rbi
->footer
= NULL
;
2818 fprintf (dump_file
, "Merged blocks %d and %d.\n",
2819 a
->index
, b
->index
);
2825 cfg_layout_split_edge (edge e
)
2828 basic_block new_bb
=
2829 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR
2830 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
2833 new_e
= make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
2834 redirect_edge_and_branch_force (e
, new_bb
);
2839 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2842 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
2846 /* Return 1 if BB ends with a call, possibly followed by some
2847 instructions that must stay with the call, 0 otherwise. */
2850 rtl_block_ends_with_call_p (basic_block bb
)
2852 rtx insn
= BB_END (bb
);
2854 while (!CALL_P (insn
)
2855 && insn
!= BB_HEAD (bb
)
2856 && keep_with_call_p (insn
))
2857 insn
= PREV_INSN (insn
);
2858 return (CALL_P (insn
));
2861 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2864 rtl_block_ends_with_condjump_p (basic_block bb
)
2866 return any_condjump_p (BB_END (bb
));
2869 /* Return true if we need to add fake edge to exit.
2870 Helper function for rtl_flow_call_edges_add. */
2873 need_fake_edge_p (rtx insn
)
2879 && !SIBLING_CALL_P (insn
)
2880 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
2881 && !find_reg_note (insn
, REG_ALWAYS_RETURN
, NULL
)
2882 && !CONST_OR_PURE_CALL_P (insn
)))
2885 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
2886 && MEM_VOLATILE_P (PATTERN (insn
)))
2887 || (GET_CODE (PATTERN (insn
)) == PARALLEL
2888 && asm_noperands (insn
) != -1
2889 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
2890 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
2893 /* Add fake edges to the function exit for any non constant and non noreturn
2894 calls, volatile inline assembly in the bitmap of blocks specified by
2895 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2898 The goal is to expose cases in which entering a basic block does not imply
2899 that all subsequent instructions must be executed. */
2902 rtl_flow_call_edges_add (sbitmap blocks
)
2905 int blocks_split
= 0;
2906 int last_bb
= last_basic_block
;
2907 bool check_last_block
= false;
2909 if (n_basic_blocks
== 0)
2913 check_last_block
= true;
2915 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
2917 /* In the last basic block, before epilogue generation, there will be
2918 a fallthru edge to EXIT. Special care is required if the last insn
2919 of the last basic block is a call because make_edge folds duplicate
2920 edges, which would result in the fallthru edge also being marked
2921 fake, which would result in the fallthru edge being removed by
2922 remove_fake_edges, which would result in an invalid CFG.
2924 Moreover, we can't elide the outgoing fake edge, since the block
2925 profiler needs to take this into account in order to solve the minimal
2926 spanning tree in the case that the call doesn't return.
2928 Handle this by adding a dummy instruction in a new last basic block. */
2929 if (check_last_block
)
2931 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
2932 rtx insn
= BB_END (bb
);
2934 /* Back up past insns that must be kept in the same block as a call. */
2935 while (insn
!= BB_HEAD (bb
)
2936 && keep_with_call_p (insn
))
2937 insn
= PREV_INSN (insn
);
2939 if (need_fake_edge_p (insn
))
2944 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2945 if (e
->dest
== EXIT_BLOCK_PTR
)
2947 insert_insn_on_edge (gen_rtx_USE (VOIDmode
, const0_rtx
), e
);
2948 commit_edge_insertions ();
2954 /* Now add fake edges to the function exit for any non constant
2955 calls since there is no way that we can determine if they will
2958 for (i
= 0; i
< last_bb
; i
++)
2960 basic_block bb
= BASIC_BLOCK (i
);
2967 if (blocks
&& !TEST_BIT (blocks
, i
))
2970 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
2972 prev_insn
= PREV_INSN (insn
);
2973 if (need_fake_edge_p (insn
))
2976 rtx split_at_insn
= insn
;
2979 /* Don't split the block between a call and an insn that should
2980 remain in the same block as the call. */
2982 while (split_at_insn
!= BB_END (bb
)
2983 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
2984 split_at_insn
= NEXT_INSN (split_at_insn
);
2986 /* The handling above of the final block before the epilogue
2987 should be enough to verify that there is no edge to the exit
2988 block in CFG already. Calling make_edge in such case would
2989 cause us to mark that edge as fake and remove it later. */
2991 #ifdef ENABLE_CHECKING
2992 if (split_at_insn
== BB_END (bb
))
2993 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
2994 if (e
->dest
== EXIT_BLOCK_PTR
)
2998 /* Note that the following may create a new basic block
2999 and renumber the existing basic blocks. */
3000 if (split_at_insn
!= BB_END (bb
))
3002 e
= split_block (bb
, split_at_insn
);
3007 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
3010 if (insn
== BB_HEAD (bb
))
3016 verify_flow_info ();
3018 return blocks_split
;
3021 /* Implementation of CFG manipulation for linearized RTL. */
3022 struct cfg_hooks rtl_cfg_hooks
= {
3024 rtl_verify_flow_info
,
3026 rtl_create_basic_block
,
3027 rtl_redirect_edge_and_branch
,
3028 rtl_redirect_edge_and_branch_force
,
3031 rtl_move_block_after
,
3032 rtl_can_merge_blocks
, /* can_merge_blocks_p */
3036 NULL
, /* can_duplicate_block_p */
3037 NULL
, /* duplicate_block */
3039 rtl_make_forwarder_block
,
3040 rtl_tidy_fallthru_edge
,
3041 rtl_block_ends_with_call_p
,
3042 rtl_block_ends_with_condjump_p
,
3043 rtl_flow_call_edges_add
3046 /* Implementation of CFG manipulation for cfg layout RTL, where
3047 basic block connected via fallthru edges does not have to be adjacent.
3048 This representation will hopefully become the default one in future
3049 version of the compiler. */
3051 /* We do not want to declare these functions in a header file, since they
3052 should only be used through the cfghooks interface, and we do not want to
3053 move them here since it would require also moving quite a lot of related
3055 extern bool cfg_layout_can_duplicate_bb_p (basic_block
);
3056 extern basic_block
cfg_layout_duplicate_bb (basic_block
);
3058 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
3060 rtl_verify_flow_info_1
,
3062 cfg_layout_create_basic_block
,
3063 cfg_layout_redirect_edge_and_branch
,
3064 cfg_layout_redirect_edge_and_branch_force
,
3065 cfg_layout_delete_block
,
3066 cfg_layout_split_block
,
3067 rtl_move_block_after
,
3068 cfg_layout_can_merge_blocks_p
,
3069 cfg_layout_merge_blocks
,
3072 cfg_layout_can_duplicate_bb_p
,
3073 cfg_layout_duplicate_bb
,
3074 cfg_layout_split_edge
,
3075 rtl_make_forwarder_block
,
3077 rtl_block_ends_with_call_p
,
3078 rtl_block_ends_with_condjump_p
,
3079 rtl_flow_call_edges_add