1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This file contains low level functions to manipulate the CFG and analyze it
21 that are aware of the RTL intermediate language.
23 Available functionality:
24 - Basic CFG/RTL manipulation API documented in cfghooks.h
25 - CFG-aware instruction chain manipulation
26 delete_insn, delete_insn_chain
27 - Edge splitting and committing to edges
28 insert_insn_on_edge, commit_edge_insertions
29 - CFG updating after insn simplification
30 purge_dead_edges, purge_all_dead_edges
31 - CFG fixing after coarse manipulation
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"
49 #include "insn-config.h"
55 #include "cfgcleanup.h"
56 #include "bb-reorder.h"
57 #include "rtl-error.h"
58 #include "insn-attr.h"
62 #include "tree-pass.h"
63 #include "print-rtl.h"
65 /* Holds the interesting leading and trailing notes for the function.
66 Only applicable if the CFG is in cfglayout mode. */
67 static GTY(()) rtx_insn
*cfg_layout_function_footer
;
68 static GTY(()) rtx_insn
*cfg_layout_function_header
;
70 static rtx_insn
*skip_insns_after_block (basic_block
);
71 static void record_effective_endpoints (void);
72 static void fixup_reorder_chain (void);
74 void verify_insn_chain (void);
75 static void fixup_fallthru_exit_predecessor (void);
76 static int can_delete_note_p (const rtx_note
*);
77 static int can_delete_label_p (const rtx_code_label
*);
78 static basic_block
rtl_split_edge (edge
);
79 static bool rtl_move_block_after (basic_block
, basic_block
);
80 static int rtl_verify_flow_info (void);
81 static basic_block
cfg_layout_split_block (basic_block
, void *);
82 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
83 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
84 static void cfg_layout_delete_block (basic_block
);
85 static void rtl_delete_block (basic_block
);
86 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
87 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
88 static basic_block
rtl_split_block (basic_block
, void *);
89 static void rtl_dump_bb (FILE *, basic_block
, int, dump_flags_t
);
90 static int rtl_verify_flow_info_1 (void);
91 static void rtl_make_forwarder_block (edge
);
93 /* Return true if NOTE is not one of the ones that must be kept paired,
94 so that we may simply delete it. */
97 can_delete_note_p (const rtx_note
*note
)
99 switch (NOTE_KIND (note
))
101 case NOTE_INSN_DELETED
:
102 case NOTE_INSN_BASIC_BLOCK
:
103 case NOTE_INSN_EPILOGUE_BEG
:
111 /* True if a given label can be deleted. */
114 can_delete_label_p (const rtx_code_label
*label
)
116 return (!LABEL_PRESERVE_P (label
)
117 /* User declared labels must be preserved. */
118 && LABEL_NAME (label
) == 0
119 && !vec_safe_contains
<rtx_insn
*> (forced_labels
,
120 const_cast<rtx_code_label
*> (label
)));
123 /* Delete INSN by patching it out. */
126 delete_insn (rtx_insn
*insn
)
129 bool really_delete
= true;
133 /* Some labels can't be directly removed from the INSN chain, as they
134 might be references via variables, constant pool etc.
135 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
136 if (! can_delete_label_p (as_a
<rtx_code_label
*> (insn
)))
138 const char *name
= LABEL_NAME (insn
);
139 basic_block bb
= BLOCK_FOR_INSN (insn
);
140 rtx_insn
*bb_note
= NEXT_INSN (insn
);
142 really_delete
= false;
143 PUT_CODE (insn
, NOTE
);
144 NOTE_KIND (insn
) = NOTE_INSN_DELETED_LABEL
;
145 NOTE_DELETED_LABEL_NAME (insn
) = name
;
147 /* If the note following the label starts a basic block, and the
148 label is a member of the same basic block, interchange the two. */
149 if (bb_note
!= NULL_RTX
150 && NOTE_INSN_BASIC_BLOCK_P (bb_note
)
152 && bb
== BLOCK_FOR_INSN (bb_note
))
154 reorder_insns_nobb (insn
, insn
, bb_note
);
155 BB_HEAD (bb
) = bb_note
;
156 if (BB_END (bb
) == bb_note
)
161 remove_node_from_insn_list (insn
, &nonlocal_goto_handler_labels
);
166 /* If this insn has already been deleted, something is very wrong. */
167 gcc_assert (!insn
->deleted ());
169 df_insn_delete (insn
);
171 insn
->set_deleted ();
174 /* If deleting a jump, decrement the use count of the label. Deleting
175 the label itself should happen in the normal course of block merging. */
178 if (JUMP_LABEL (insn
)
179 && LABEL_P (JUMP_LABEL (insn
)))
180 LABEL_NUSES (JUMP_LABEL (insn
))--;
182 /* If there are more targets, remove them too. */
184 = find_reg_note (insn
, REG_LABEL_TARGET
, NULL_RTX
)) != NULL_RTX
185 && LABEL_P (XEXP (note
, 0)))
187 LABEL_NUSES (XEXP (note
, 0))--;
188 remove_note (insn
, note
);
192 /* Also if deleting any insn that references a label as an operand. */
193 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, NULL_RTX
)) != NULL_RTX
194 && LABEL_P (XEXP (note
, 0)))
196 LABEL_NUSES (XEXP (note
, 0))--;
197 remove_note (insn
, note
);
200 if (rtx_jump_table_data
*table
= dyn_cast
<rtx_jump_table_data
*> (insn
))
202 rtvec vec
= table
->get_labels ();
203 int len
= GET_NUM_ELEM (vec
);
206 for (i
= 0; i
< len
; i
++)
208 rtx label
= XEXP (RTVEC_ELT (vec
, i
), 0);
210 /* When deleting code in bulk (e.g. removing many unreachable
211 blocks) we can delete a label that's a target of the vector
212 before deleting the vector itself. */
214 LABEL_NUSES (label
)--;
219 /* Like delete_insn but also purge dead edges from BB.
220 Return true if any edges are eliminated. */
223 delete_insn_and_edges (rtx_insn
*insn
)
228 && BLOCK_FOR_INSN (insn
)
229 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
233 return purge_dead_edges (BLOCK_FOR_INSN (insn
));
237 /* Unlink a chain of insns between START and FINISH, leaving notes
238 that must be paired. If CLEAR_BB is true, we set bb field for
239 insns that cannot be removed to NULL. */
242 delete_insn_chain (rtx start
, rtx_insn
*finish
, bool clear_bb
)
244 /* Unchain the insns one by one. It would be quicker to delete all of these
245 with a single unchaining, rather than one at a time, but we need to keep
247 rtx_insn
*current
= finish
;
250 rtx_insn
*prev
= PREV_INSN (current
);
251 if (NOTE_P (current
) && !can_delete_note_p (as_a
<rtx_note
*> (current
)))
254 delete_insn (current
);
256 if (clear_bb
&& !current
->deleted ())
257 set_block_for_insn (current
, NULL
);
259 if (current
== start
)
265 /* Create a new basic block consisting of the instructions between HEAD and END
266 inclusive. This function is designed to allow fast BB construction - reuses
267 the note and basic block struct in BB_NOTE, if any and do not grow
268 BASIC_BLOCK chain and should be used directly only by CFG construction code.
269 END can be NULL in to create new empty basic block before HEAD. Both END
270 and HEAD can be NULL to create basic block at the end of INSN chain.
271 AFTER is the basic block we should be put after. */
274 create_basic_block_structure (rtx_insn
*head
, rtx_insn
*end
, rtx_note
*bb_note
,
280 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
283 /* If we found an existing note, thread it back onto the chain. */
291 after
= PREV_INSN (head
);
295 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
296 reorder_insns_nobb (bb_note
, bb_note
, after
);
300 /* Otherwise we must create a note and a basic block structure. */
304 init_rtl_bb_info (bb
);
307 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
308 else if (LABEL_P (head
) && end
)
310 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
316 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
322 NOTE_BASIC_BLOCK (bb_note
) = bb
;
325 /* Always include the bb note in the block. */
326 if (NEXT_INSN (end
) == bb_note
)
331 bb
->index
= last_basic_block_for_fn (cfun
)++;
332 bb
->flags
= BB_NEW
| BB_RTL
;
333 link_block (bb
, after
);
334 SET_BASIC_BLOCK_FOR_FN (cfun
, bb
->index
, bb
);
335 df_bb_refs_record (bb
->index
, false);
336 update_bb_for_insn (bb
);
337 BB_SET_PARTITION (bb
, BB_UNPARTITIONED
);
339 /* Tag the block so that we know it has been used when considering
340 other basic block notes. */
346 /* Create new basic block consisting of instructions in between HEAD and END
347 and place it to the BB chain after block AFTER. END can be NULL to
348 create a new empty basic block before HEAD. Both END and HEAD can be
349 NULL to create basic block at the end of INSN chain. */
352 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
354 rtx_insn
*head
= (rtx_insn
*) headp
;
355 rtx_insn
*end
= (rtx_insn
*) endp
;
358 /* Grow the basic block array if needed. */
359 if ((size_t) last_basic_block_for_fn (cfun
)
360 >= basic_block_info_for_fn (cfun
)->length ())
363 (last_basic_block_for_fn (cfun
)
364 + (last_basic_block_for_fn (cfun
) + 3) / 4);
365 vec_safe_grow_cleared (basic_block_info_for_fn (cfun
), new_size
);
368 n_basic_blocks_for_fn (cfun
)++;
370 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
376 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
378 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
383 /* Delete the insns in a (non-live) block. We physically delete every
384 non-deleted-note insn, and update the flow graph appropriately.
386 Return nonzero if we deleted an exception handler. */
388 /* ??? Preserving all such notes strikes me as wrong. It would be nice
389 to post-process the stream to remove empty blocks, loops, ranges, etc. */
392 rtl_delete_block (basic_block b
)
394 rtx_insn
*insn
, *end
;
396 /* If the head of this block is a CODE_LABEL, then it might be the
397 label for an exception handler which can't be reached. We need
398 to remove the label from the exception_handler_label list. */
401 end
= get_last_bb_insn (b
);
403 /* Selectively delete the entire chain. */
405 delete_insn_chain (insn
, end
, true);
409 fprintf (dump_file
, "deleting block %d\n", b
->index
);
410 df_bb_delete (b
->index
);
413 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
416 compute_bb_for_insn (void)
420 FOR_EACH_BB_FN (bb
, cfun
)
422 rtx_insn
*end
= BB_END (bb
);
425 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
427 BLOCK_FOR_INSN (insn
) = bb
;
434 /* Release the basic_block_for_insn array. */
437 free_bb_for_insn (void)
440 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
441 if (!BARRIER_P (insn
))
442 BLOCK_FOR_INSN (insn
) = NULL
;
448 const pass_data pass_data_free_cfg
=
451 "*free_cfg", /* name */
452 OPTGROUP_NONE
, /* optinfo_flags */
454 0, /* properties_required */
455 0, /* properties_provided */
456 PROP_cfg
, /* properties_destroyed */
457 0, /* todo_flags_start */
458 0, /* todo_flags_finish */
461 class pass_free_cfg
: public rtl_opt_pass
464 pass_free_cfg (gcc::context
*ctxt
)
465 : rtl_opt_pass (pass_data_free_cfg
, ctxt
)
468 /* opt_pass methods: */
469 virtual unsigned int execute (function
*);
471 }; // class pass_free_cfg
474 pass_free_cfg::execute (function
*)
476 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
477 valid at that point so it would be too late to call df_analyze. */
478 if (DELAY_SLOTS
&& optimize
> 0 && flag_delayed_branch
)
480 df_note_add_problem ();
484 if (crtl
->has_bb_partition
)
485 insert_section_boundary_note ();
494 make_pass_free_cfg (gcc::context
*ctxt
)
496 return new pass_free_cfg (ctxt
);
499 /* Return RTX to emit after when we want to emit code on the entry of function. */
501 entry_of_function (void)
503 return (n_basic_blocks_for_fn (cfun
) > NUM_FIXED_BLOCKS
?
504 BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
) : get_insns ());
507 /* Emit INSN at the entry point of the function, ensuring that it is only
508 executed once per function. */
510 emit_insn_at_entry (rtx insn
)
512 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
513 edge e
= ei_safe_edge (ei
);
514 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
516 insert_insn_on_edge (insn
, e
);
517 commit_edge_insertions ();
520 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
521 (or BARRIER if found) and notify df of the bb change.
522 The insn chain range is inclusive
523 (i.e. both BEGIN and END will be updated. */
526 update_bb_for_insn_chain (rtx_insn
*begin
, rtx_insn
*end
, basic_block bb
)
530 end
= NEXT_INSN (end
);
531 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
532 if (!BARRIER_P (insn
))
533 df_insn_change_bb (insn
, bb
);
536 /* Update BLOCK_FOR_INSN of insns in BB to BB,
537 and notify df of the change. */
540 update_bb_for_insn (basic_block bb
)
542 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
546 /* Like active_insn_p, except keep the return value clobber around
547 even after reload. */
550 flow_active_insn_p (const rtx_insn
*insn
)
552 if (active_insn_p (insn
))
555 /* A clobber of the function return value exists for buggy
556 programs that fail to return a value. Its effect is to
557 keep the return value from being live across the entire
558 function. If we allow it to be skipped, we introduce the
559 possibility for register lifetime confusion. */
560 if (GET_CODE (PATTERN (insn
)) == CLOBBER
561 && REG_P (XEXP (PATTERN (insn
), 0))
562 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn
), 0)))
568 /* Return true if the block has no effect and only forwards control flow to
569 its single destination. */
572 contains_no_active_insn_p (const_basic_block bb
)
576 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
577 || bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
578 || !single_succ_p (bb
)
579 || (single_succ_edge (bb
)->flags
& EDGE_FAKE
) != 0)
582 for (insn
= BB_HEAD (bb
); insn
!= BB_END (bb
); insn
= NEXT_INSN (insn
))
583 if (INSN_P (insn
) && flow_active_insn_p (insn
))
586 return (!INSN_P (insn
)
587 || (JUMP_P (insn
) && simplejump_p (insn
))
588 || !flow_active_insn_p (insn
));
591 /* Likewise, but protect loop latches, headers and preheaders. */
592 /* FIXME: Make this a cfg hook. */
595 forwarder_block_p (const_basic_block bb
)
597 if (!contains_no_active_insn_p (bb
))
600 /* Protect loop latches, headers and preheaders. */
604 if (bb
->loop_father
->header
== bb
)
606 dest
= EDGE_SUCC (bb
, 0)->dest
;
607 if (dest
->loop_father
->header
== dest
)
614 /* Return nonzero if we can reach target from src by falling through. */
615 /* FIXME: Make this a cfg hook, the result is only valid in cfgrtl mode. */
618 can_fallthru (basic_block src
, basic_block target
)
620 rtx_insn
*insn
= BB_END (src
);
625 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
627 if (src
->next_bb
!= target
)
630 /* ??? Later we may add code to move jump tables offline. */
631 if (tablejump_p (insn
, NULL
, NULL
))
634 FOR_EACH_EDGE (e
, ei
, src
->succs
)
635 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
636 && e
->flags
& EDGE_FALLTHRU
)
639 insn2
= BB_HEAD (target
);
640 if (!active_insn_p (insn2
))
641 insn2
= next_active_insn (insn2
);
643 return next_active_insn (insn
) == insn2
;
646 /* Return nonzero if we could reach target from src by falling through,
647 if the target was made adjacent. If we already have a fall-through
648 edge to the exit block, we can't do that. */
650 could_fall_through (basic_block src
, basic_block target
)
655 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
657 FOR_EACH_EDGE (e
, ei
, src
->succs
)
658 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
659 && e
->flags
& EDGE_FALLTHRU
)
664 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
666 bb_note (basic_block bb
)
672 note
= NEXT_INSN (note
);
674 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note
));
675 return as_a
<rtx_note
*> (note
);
678 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
679 note associated with the BLOCK. */
682 first_insn_after_basic_block_note (basic_block block
)
686 /* Get the first instruction in the block. */
687 insn
= BB_HEAD (block
);
689 if (insn
== NULL_RTX
)
692 insn
= NEXT_INSN (insn
);
693 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
695 return NEXT_INSN (insn
);
698 /* Creates a new basic block just after basic block BB by splitting
699 everything after specified instruction INSNP. */
702 rtl_split_block (basic_block bb
, void *insnp
)
705 rtx_insn
*insn
= (rtx_insn
*) insnp
;
711 insn
= first_insn_after_basic_block_note (bb
);
715 rtx_insn
*next
= insn
;
717 insn
= PREV_INSN (insn
);
719 /* If the block contains only debug insns, insn would have
720 been NULL in a non-debug compilation, and then we'd end
721 up emitting a DELETED note. For -fcompare-debug
722 stability, emit the note too. */
723 if (insn
!= BB_END (bb
)
724 && DEBUG_INSN_P (next
)
725 && DEBUG_INSN_P (BB_END (bb
)))
727 while (next
!= BB_END (bb
) && DEBUG_INSN_P (next
))
728 next
= NEXT_INSN (next
);
730 if (next
== BB_END (bb
))
731 emit_note_after (NOTE_INSN_DELETED
, next
);
735 insn
= get_last_insn ();
738 /* We probably should check type of the insn so that we do not create
739 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
741 if (insn
== BB_END (bb
))
742 emit_note_after (NOTE_INSN_DELETED
, insn
);
744 /* Create the new basic block. */
745 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
746 BB_COPY_PARTITION (new_bb
, bb
);
749 /* Redirect the outgoing edges. */
750 new_bb
->succs
= bb
->succs
;
752 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
755 /* The new block starts off being dirty. */
756 df_set_bb_dirty (bb
);
760 /* Return true if the single edge between blocks A and B is the only place
761 in RTL which holds some unique locus. */
764 unique_locus_on_edge_between_p (basic_block a
, basic_block b
)
766 const location_t goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
767 rtx_insn
*insn
, *end
;
769 if (LOCATION_LOCUS (goto_locus
) == UNKNOWN_LOCATION
)
772 /* First scan block A backward. */
774 end
= PREV_INSN (BB_HEAD (a
));
775 while (insn
!= end
&& (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
776 insn
= PREV_INSN (insn
);
778 if (insn
!= end
&& INSN_LOCATION (insn
) == goto_locus
)
781 /* Then scan block B forward. */
785 end
= NEXT_INSN (BB_END (b
));
786 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
787 insn
= NEXT_INSN (insn
);
789 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
790 && INSN_LOCATION (insn
) == goto_locus
)
797 /* If the single edge between blocks A and B is the only place in RTL which
798 holds some unique locus, emit a nop with that locus between the blocks. */
801 emit_nop_for_unique_locus_between (basic_block a
, basic_block b
)
803 if (!unique_locus_on_edge_between_p (a
, b
))
806 BB_END (a
) = emit_insn_after_noloc (gen_nop (), BB_END (a
), a
);
807 INSN_LOCATION (BB_END (a
)) = EDGE_SUCC (a
, 0)->goto_locus
;
810 /* Blocks A and B are to be merged into a single block A. The insns
811 are already contiguous. */
814 rtl_merge_blocks (basic_block a
, basic_block b
)
816 rtx_insn
*b_head
= BB_HEAD (b
), *b_end
= BB_END (b
), *a_end
= BB_END (a
);
817 rtx_insn
*del_first
= NULL
, *del_last
= NULL
;
818 rtx_insn
*b_debug_start
= b_end
, *b_debug_end
= b_end
;
819 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
823 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
826 while (DEBUG_INSN_P (b_end
))
827 b_end
= PREV_INSN (b_debug_start
= b_end
);
829 /* If there was a CODE_LABEL beginning B, delete it. */
830 if (LABEL_P (b_head
))
832 /* Detect basic blocks with nothing but a label. This can happen
833 in particular at the end of a function. */
837 del_first
= del_last
= b_head
;
838 b_head
= NEXT_INSN (b_head
);
841 /* Delete the basic block note and handle blocks containing just that
843 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
851 b_head
= NEXT_INSN (b_head
);
854 /* If there was a jump out of A, delete it. */
859 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
861 || NOTE_INSN_BASIC_BLOCK_P (prev
)
862 || prev
== BB_HEAD (a
))
867 /* If this was a conditional jump, we need to also delete
868 the insn that set cc0. */
869 if (HAVE_cc0
&& only_sets_cc0_p (prev
))
871 rtx_insn
*tmp
= prev
;
873 prev
= prev_nonnote_insn (prev
);
879 a_end
= PREV_INSN (del_first
);
881 else if (BARRIER_P (NEXT_INSN (a_end
)))
882 del_first
= NEXT_INSN (a_end
);
884 /* Delete everything marked above as well as crap that might be
885 hanging out between the two blocks. */
887 BB_HEAD (b
) = b_empty
? NULL
: b_head
;
888 delete_insn_chain (del_first
, del_last
, true);
890 /* When not optimizing and the edge is the only place in RTL which holds
891 some unique locus, emit a nop with that locus in between. */
894 emit_nop_for_unique_locus_between (a
, b
);
898 /* Reassociate the insns of B with A. */
901 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
903 BB_END (a
) = b_debug_end
;
906 else if (b_end
!= b_debug_end
)
908 /* Move any deleted labels and other notes between the end of A
909 and the debug insns that make up B after the debug insns,
910 bringing the debug insns into A while keeping the notes after
912 if (NEXT_INSN (a_end
) != b_debug_start
)
913 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
915 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
916 BB_END (a
) = b_debug_end
;
919 df_bb_delete (b
->index
);
921 /* If B was a forwarder block, propagate the locus on the edge. */
923 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
924 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
927 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
931 /* Return true when block A and B can be merged. */
934 rtl_can_merge_blocks (basic_block a
, basic_block b
)
936 /* If we are partitioning hot/cold basic blocks, we don't want to
937 mess up unconditional or indirect jumps that cross between hot
940 Basic block partitioning may result in some jumps that appear to
941 be optimizable (or blocks that appear to be mergeable), but which really
942 must be left untouched (they are required to make it safely across
943 partition boundaries). See the comments at the top of
944 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
946 if (BB_PARTITION (a
) != BB_PARTITION (b
))
949 /* Protect the loop latches. */
950 if (current_loops
&& b
->loop_father
->latch
== b
)
953 /* There must be exactly one edge in between the blocks. */
954 return (single_succ_p (a
)
955 && single_succ (a
) == b
958 /* Must be simple edge. */
959 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
961 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
962 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
963 /* If the jump insn has side effects,
964 we can't kill the edge. */
965 && (!JUMP_P (BB_END (a
))
967 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
970 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
974 block_label (basic_block block
)
976 if (block
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
979 if (!LABEL_P (BB_HEAD (block
)))
981 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
984 return as_a
<rtx_code_label
*> (BB_HEAD (block
));
987 /* Attempt to perform edge redirection by replacing possibly complex jump
988 instruction by unconditional jump or removing jump completely. This can
989 apply only if all edges now point to the same block. The parameters and
990 return values are equivalent to redirect_edge_and_branch. */
993 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
995 basic_block src
= e
->src
;
996 rtx_insn
*insn
= BB_END (src
), *kill_from
;
1000 /* If we are partitioning hot/cold basic blocks, we don't want to
1001 mess up unconditional or indirect jumps that cross between hot
1004 Basic block partitioning may result in some jumps that appear to
1005 be optimizable (or blocks that appear to be mergeable), but which really
1006 must be left untouched (they are required to make it safely across
1007 partition boundaries). See the comments at the top of
1008 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
1010 if (BB_PARTITION (src
) != BB_PARTITION (target
))
1013 /* We can replace or remove a complex jump only when we have exactly
1014 two edges. Also, if we have exactly one outgoing edge, we can
1016 if (EDGE_COUNT (src
->succs
) >= 3
1017 /* Verify that all targets will be TARGET. Specifically, the
1018 edge that is not E must also go to TARGET. */
1019 || (EDGE_COUNT (src
->succs
) == 2
1020 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
1023 if (!onlyjump_p (insn
))
1025 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
1028 /* Avoid removing branch with side effects. */
1029 set
= single_set (insn
);
1030 if (!set
|| side_effects_p (set
))
1033 /* In case we zap a conditional jump, we'll need to kill
1034 the cc0 setter too. */
1036 if (HAVE_cc0
&& reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
1037 && only_sets_cc0_p (PREV_INSN (insn
)))
1038 kill_from
= PREV_INSN (insn
);
1040 /* See if we can create the fallthru edge. */
1041 if (in_cfglayout
|| can_fallthru (src
, target
))
1044 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
1047 /* Selectively unlink whole insn chain. */
1050 rtx_insn
*insn
= BB_FOOTER (src
);
1052 delete_insn_chain (kill_from
, BB_END (src
), false);
1054 /* Remove barriers but keep jumptables. */
1057 if (BARRIER_P (insn
))
1059 if (PREV_INSN (insn
))
1060 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
1062 BB_FOOTER (src
) = NEXT_INSN (insn
);
1063 if (NEXT_INSN (insn
))
1064 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
1068 insn
= NEXT_INSN (insn
);
1072 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
1076 /* If this already is simplejump, redirect it. */
1077 else if (simplejump_p (insn
))
1079 if (e
->dest
== target
)
1082 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
1083 INSN_UID (insn
), e
->dest
->index
, target
->index
);
1084 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1085 block_label (target
), 0))
1087 gcc_assert (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1092 /* Cannot do anything for target exit block. */
1093 else if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1096 /* Or replace possibly complicated jump insn by simple jump insn. */
1099 rtx_code_label
*target_label
= block_label (target
);
1102 rtx_jump_table_data
*table
;
1104 emit_jump_insn_after_noloc (targetm
.gen_jump (target_label
), insn
);
1105 JUMP_LABEL (BB_END (src
)) = target_label
;
1106 LABEL_NUSES (target_label
)++;
1108 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
1109 INSN_UID (insn
), INSN_UID (BB_END (src
)));
1112 delete_insn_chain (kill_from
, insn
, false);
1114 /* Recognize a tablejump that we are converting to a
1115 simple jump and remove its associated CODE_LABEL
1116 and ADDR_VEC or ADDR_DIFF_VEC. */
1117 if (tablejump_p (insn
, &label
, &table
))
1118 delete_insn_chain (label
, table
, false);
1120 barrier
= next_nonnote_insn (BB_END (src
));
1121 if (!barrier
|| !BARRIER_P (barrier
))
1122 emit_barrier_after (BB_END (src
));
1125 if (barrier
!= NEXT_INSN (BB_END (src
)))
1127 /* Move the jump before barrier so that the notes
1128 which originally were or were created before jump table are
1129 inside the basic block. */
1130 rtx_insn
*new_insn
= BB_END (src
);
1132 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
1133 PREV_INSN (barrier
), src
);
1135 SET_NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
1136 SET_PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
1138 SET_NEXT_INSN (new_insn
) = barrier
;
1139 SET_NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
1141 SET_PREV_INSN (new_insn
) = PREV_INSN (barrier
);
1142 SET_PREV_INSN (barrier
) = new_insn
;
1147 /* Keep only one edge out and set proper flags. */
1148 if (!single_succ_p (src
))
1150 gcc_assert (single_succ_p (src
));
1152 e
= single_succ_edge (src
);
1154 e
->flags
= EDGE_FALLTHRU
;
1158 e
->probability
= profile_probability::always ();
1160 if (e
->dest
!= target
)
1161 redirect_edge_succ (e
, target
);
1165 /* Subroutine of redirect_branch_edge that tries to patch the jump
1166 instruction INSN so that it reaches block NEW. Do this
1167 only when it originally reached block OLD. Return true if this
1168 worked or the original target wasn't OLD, return false if redirection
1172 patch_jump_insn (rtx_insn
*insn
, rtx_insn
*old_label
, basic_block new_bb
)
1174 rtx_jump_table_data
*table
;
1176 /* Recognize a tablejump and adjust all matching cases. */
1177 if (tablejump_p (insn
, NULL
, &table
))
1181 rtx_code_label
*new_label
= block_label (new_bb
);
1183 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1185 vec
= table
->get_labels ();
1187 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
1188 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
1190 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
1191 --LABEL_NUSES (old_label
);
1192 ++LABEL_NUSES (new_label
);
1195 /* Handle casesi dispatch insns. */
1196 if ((tmp
= single_set (insn
)) != NULL
1197 && SET_DEST (tmp
) == pc_rtx
1198 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
1199 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
1200 && label_ref_label (XEXP (SET_SRC (tmp
), 2)) == old_label
)
1202 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
1204 --LABEL_NUSES (old_label
);
1205 ++LABEL_NUSES (new_label
);
1208 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
1210 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
1213 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1215 rtx_code_label
*new_label
= block_label (new_bb
);
1217 for (i
= 0; i
< n
; ++i
)
1219 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
1220 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
1221 if (XEXP (old_ref
, 0) == old_label
)
1223 ASM_OPERANDS_LABEL (tmp
, i
)
1224 = gen_rtx_LABEL_REF (Pmode
, new_label
);
1225 --LABEL_NUSES (old_label
);
1226 ++LABEL_NUSES (new_label
);
1230 if (JUMP_LABEL (insn
) == old_label
)
1232 JUMP_LABEL (insn
) = new_label
;
1233 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1235 remove_note (insn
, note
);
1239 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1241 remove_note (insn
, note
);
1242 if (JUMP_LABEL (insn
) != new_label
1243 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1244 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1246 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1248 XEXP (note
, 0) = new_label
;
1252 /* ?? We may play the games with moving the named labels from
1253 one basic block to the other in case only one computed_jump is
1255 if (computed_jump_p (insn
)
1256 /* A return instruction can't be redirected. */
1257 || returnjump_p (insn
))
1260 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1262 /* If the insn doesn't go where we think, we're confused. */
1263 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1265 /* If the substitution doesn't succeed, die. This can happen
1266 if the back end emitted unrecognizable instructions or if
1267 target is exit block on some arches. */
1268 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1269 block_label (new_bb
), 0))
1271 gcc_assert (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1280 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1283 redirect_branch_edge (edge e
, basic_block target
)
1285 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1286 basic_block src
= e
->src
;
1287 rtx_insn
*insn
= BB_END (src
);
1289 /* We can only redirect non-fallthru edges of jump insn. */
1290 if (e
->flags
& EDGE_FALLTHRU
)
1292 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1295 if (!currently_expanding_to_rtl
)
1297 if (!patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
), old_label
, target
))
1301 /* When expanding this BB might actually contain multiple
1302 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1303 Redirect all of those that match our label. */
1304 FOR_BB_INSNS (src
, insn
)
1305 if (JUMP_P (insn
) && !patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
),
1310 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1311 e
->src
->index
, e
->dest
->index
, target
->index
);
1313 if (e
->dest
!= target
)
1314 e
= redirect_edge_succ_nodup (e
, target
);
1319 /* Called when edge E has been redirected to a new destination,
1320 in order to update the region crossing flag on the edge and
1324 fixup_partition_crossing (edge e
)
1326 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
) || e
->dest
1327 == EXIT_BLOCK_PTR_FOR_FN (cfun
))
1329 /* If we redirected an existing edge, it may already be marked
1330 crossing, even though the new src is missing a reg crossing note.
1331 But make sure reg crossing note doesn't already exist before
1333 if (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
))
1335 e
->flags
|= EDGE_CROSSING
;
1336 if (JUMP_P (BB_END (e
->src
))
1337 && !CROSSING_JUMP_P (BB_END (e
->src
)))
1338 CROSSING_JUMP_P (BB_END (e
->src
)) = 1;
1340 else if (BB_PARTITION (e
->src
) == BB_PARTITION (e
->dest
))
1342 e
->flags
&= ~EDGE_CROSSING
;
1343 /* Remove the section crossing note from jump at end of
1344 src if it exists, and if no other successors are
1346 if (JUMP_P (BB_END (e
->src
)) && CROSSING_JUMP_P (BB_END (e
->src
)))
1348 bool has_crossing_succ
= false;
1351 FOR_EACH_EDGE (e2
, ei
, e
->src
->succs
)
1353 has_crossing_succ
|= (e2
->flags
& EDGE_CROSSING
);
1354 if (has_crossing_succ
)
1357 if (!has_crossing_succ
)
1358 CROSSING_JUMP_P (BB_END (e
->src
)) = 0;
1363 /* Called when block BB has been reassigned to the cold partition,
1364 because it is now dominated by another cold block,
1365 to ensure that the region crossing attributes are updated. */
1368 fixup_new_cold_bb (basic_block bb
)
1373 /* This is called when a hot bb is found to now be dominated
1374 by a cold bb and therefore needs to become cold. Therefore,
1375 its preds will no longer be region crossing. Any non-dominating
1376 preds that were previously hot would also have become cold
1377 in the caller for the same region. Any preds that were previously
1378 region-crossing will be adjusted in fixup_partition_crossing. */
1379 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1381 fixup_partition_crossing (e
);
1384 /* Possibly need to make bb's successor edges region crossing,
1385 or remove stale region crossing. */
1386 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1388 /* We can't have fall-through edges across partition boundaries.
1389 Note that force_nonfallthru will do any necessary partition
1390 boundary fixup by calling fixup_partition_crossing itself. */
1391 if ((e
->flags
& EDGE_FALLTHRU
)
1392 && BB_PARTITION (bb
) != BB_PARTITION (e
->dest
)
1393 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1394 force_nonfallthru (e
);
1396 fixup_partition_crossing (e
);
1400 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1401 expense of adding new instructions or reordering basic blocks.
1403 Function can be also called with edge destination equivalent to the TARGET.
1404 Then it should try the simplifications and do nothing if none is possible.
1406 Return edge representing the branch if transformation succeeded. Return NULL
1408 We still return NULL in case E already destinated TARGET and we didn't
1409 managed to simplify instruction stream. */
1412 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1415 basic_block src
= e
->src
;
1416 basic_block dest
= e
->dest
;
1418 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1424 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1426 df_set_bb_dirty (src
);
1427 fixup_partition_crossing (ret
);
1431 ret
= redirect_branch_edge (e
, target
);
1435 df_set_bb_dirty (src
);
1436 fixup_partition_crossing (ret
);
1440 /* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */
1443 emit_barrier_after_bb (basic_block bb
)
1445 rtx_barrier
*barrier
= emit_barrier_after (BB_END (bb
));
1446 gcc_assert (current_ir_type () == IR_RTL_CFGRTL
1447 || current_ir_type () == IR_RTL_CFGLAYOUT
);
1448 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
1450 rtx_insn
*insn
= unlink_insn_chain (barrier
, barrier
);
1454 rtx_insn
*footer_tail
= BB_FOOTER (bb
);
1456 while (NEXT_INSN (footer_tail
))
1457 footer_tail
= NEXT_INSN (footer_tail
);
1458 if (!BARRIER_P (footer_tail
))
1460 SET_NEXT_INSN (footer_tail
) = insn
;
1461 SET_PREV_INSN (insn
) = footer_tail
;
1465 BB_FOOTER (bb
) = insn
;
1469 /* Like force_nonfallthru below, but additionally performs redirection
1470 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1471 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1472 simple_return_rtx, indicating which kind of returnjump to create.
1473 It should be NULL otherwise. */
1476 force_nonfallthru_and_redirect (edge e
, basic_block target
, rtx jump_label
)
1478 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1481 int abnormal_edge_flags
= 0;
1482 bool asm_goto_edge
= false;
1485 /* In the case the last instruction is conditional jump to the next
1486 instruction, first redirect the jump itself and then continue
1487 by creating a basic block afterwards to redirect fallthru edge. */
1488 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
1489 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1490 && any_condjump_p (BB_END (e
->src
))
1491 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1494 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1497 redirected
= redirect_jump (as_a
<rtx_jump_insn
*> (BB_END (e
->src
)),
1498 block_label (target
), 0);
1499 gcc_assert (redirected
);
1501 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1504 int prob
= XINT (note
, 0);
1506 b
->probability
= profile_probability::from_reg_br_prob_note (prob
);
1507 e
->probability
-= e
->probability
;
1511 if (e
->flags
& EDGE_ABNORMAL
)
1513 /* Irritating special case - fallthru edge to the same block as abnormal
1515 We can't redirect abnormal edge, but we still can split the fallthru
1516 one and create separate abnormal edge to original destination.
1517 This allows bb-reorder to make such edge non-fallthru. */
1518 gcc_assert (e
->dest
== target
);
1519 abnormal_edge_flags
= e
->flags
& ~EDGE_FALLTHRU
;
1520 e
->flags
&= EDGE_FALLTHRU
;
1524 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1525 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1527 /* We can't redirect the entry block. Create an empty block
1528 at the start of the function which we use to add the new
1534 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
,
1535 ENTRY_BLOCK_PTR_FOR_FN (cfun
));
1536 bb
->count
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->count
;
1538 /* Change the existing edge's source to be the new block, and add
1539 a new edge from the entry block to the new block. */
1541 for (ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
1542 (tmp
= ei_safe_edge (ei
)); )
1546 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
->unordered_remove (ei
.index
);
1556 vec_safe_push (bb
->succs
, e
);
1557 make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun
), bb
,
1562 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1563 don't point to the target or fallthru label. */
1564 if (JUMP_P (BB_END (e
->src
))
1565 && target
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1566 && (e
->flags
& EDGE_FALLTHRU
)
1567 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1569 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1570 bool adjust_jump_target
= false;
1572 for (i
= 0; i
< n
; ++i
)
1574 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1576 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1577 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1578 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1579 adjust_jump_target
= true;
1581 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1582 asm_goto_edge
= true;
1584 if (adjust_jump_target
)
1586 rtx_insn
*insn
= BB_END (e
->src
);
1588 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1589 rtx_insn
*new_label
= BB_HEAD (target
);
1591 if (JUMP_LABEL (insn
) == old_label
)
1593 JUMP_LABEL (insn
) = new_label
;
1594 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1596 remove_note (insn
, note
);
1600 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1602 remove_note (insn
, note
);
1603 if (JUMP_LABEL (insn
) != new_label
1604 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1605 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1607 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1609 XEXP (note
, 0) = new_label
;
1613 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1616 profile_count count
= e
->count ();
1617 profile_probability probability
= e
->probability
;
1618 /* Create the new structures. */
1620 /* If the old block ended with a tablejump, skip its table
1621 by searching forward from there. Otherwise start searching
1622 forward from the last instruction of the old block. */
1623 rtx_jump_table_data
*table
;
1624 if (tablejump_p (BB_END (e
->src
), NULL
, &table
))
1627 new_head
= BB_END (e
->src
);
1628 new_head
= NEXT_INSN (new_head
);
1630 jump_block
= create_basic_block (new_head
, NULL
, e
->src
);
1631 jump_block
->count
= count
;
1633 /* Make sure new block ends up in correct hot/cold section. */
1635 BB_COPY_PARTITION (jump_block
, e
->src
);
1638 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1639 new_edge
->probability
= probability
;
1641 /* Redirect old edge. */
1642 redirect_edge_pred (e
, jump_block
);
1643 e
->probability
= profile_probability::always ();
1645 /* If e->src was previously region crossing, it no longer is
1646 and the reg crossing note should be removed. */
1647 fixup_partition_crossing (new_edge
);
1649 /* If asm goto has any label refs to target's label,
1650 add also edge from asm goto bb to target. */
1653 new_edge
->probability
= new_edge
->probability
.apply_scale (1, 2);
1654 jump_block
->count
= jump_block
->count
.apply_scale (1, 2);
1655 edge new_edge2
= make_edge (new_edge
->src
, target
,
1656 e
->flags
& ~EDGE_FALLTHRU
);
1657 new_edge2
->probability
= probability
- new_edge
->probability
;
1660 new_bb
= jump_block
;
1663 jump_block
= e
->src
;
1665 loc
= e
->goto_locus
;
1666 e
->flags
&= ~EDGE_FALLTHRU
;
1667 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1669 if (jump_label
== ret_rtx
)
1670 emit_jump_insn_after_setloc (targetm
.gen_return (),
1671 BB_END (jump_block
), loc
);
1674 gcc_assert (jump_label
== simple_return_rtx
);
1675 emit_jump_insn_after_setloc (targetm
.gen_simple_return (),
1676 BB_END (jump_block
), loc
);
1678 set_return_jump_label (BB_END (jump_block
));
1682 rtx_code_label
*label
= block_label (target
);
1683 emit_jump_insn_after_setloc (targetm
.gen_jump (label
),
1684 BB_END (jump_block
), loc
);
1685 JUMP_LABEL (BB_END (jump_block
)) = label
;
1686 LABEL_NUSES (label
)++;
1689 /* We might be in cfg layout mode, and if so, the following routine will
1690 insert the barrier correctly. */
1691 emit_barrier_after_bb (jump_block
);
1692 redirect_edge_succ_nodup (e
, target
);
1694 if (abnormal_edge_flags
)
1695 make_edge (src
, target
, abnormal_edge_flags
);
1697 df_mark_solutions_dirty ();
1698 fixup_partition_crossing (e
);
1702 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1703 (and possibly create new basic block) to make edge non-fallthru.
1704 Return newly created BB or NULL if none. */
1707 rtl_force_nonfallthru (edge e
)
1709 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1712 /* Redirect edge even at the expense of creating new jump insn or
1713 basic block. Return new basic block if created, NULL otherwise.
1714 Conversion must be possible. */
1717 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1719 if (redirect_edge_and_branch (e
, target
)
1720 || e
->dest
== target
)
1723 /* In case the edge redirection failed, try to force it to be non-fallthru
1724 and redirect newly created simplejump. */
1725 df_set_bb_dirty (e
->src
);
1726 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1729 /* The given edge should potentially be a fallthru edge. If that is in
1730 fact true, delete the jump and barriers that are in the way. */
1733 rtl_tidy_fallthru_edge (edge e
)
1736 basic_block b
= e
->src
, c
= b
->next_bb
;
1738 /* ??? In a late-running flow pass, other folks may have deleted basic
1739 blocks by nopping out blocks, leaving multiple BARRIERs between here
1740 and the target label. They ought to be chastised and fixed.
1742 We can also wind up with a sequence of undeletable labels between
1743 one block and the next.
1745 So search through a sequence of barriers, labels, and notes for
1746 the head of block C and assert that we really do fall through. */
1748 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1752 /* Remove what will soon cease being the jump insn from the source block.
1753 If block B consisted only of this single jump, turn it into a deleted
1758 && (any_uncondjump_p (q
)
1759 || single_succ_p (b
)))
1762 rtx_jump_table_data
*table
;
1764 if (tablejump_p (q
, &label
, &table
))
1766 /* The label is likely mentioned in some instruction before
1767 the tablejump and might not be DCEd, so turn it into
1768 a note instead and move before the tablejump that is going to
1770 const char *name
= LABEL_NAME (label
);
1771 PUT_CODE (label
, NOTE
);
1772 NOTE_KIND (label
) = NOTE_INSN_DELETED_LABEL
;
1773 NOTE_DELETED_LABEL_NAME (label
) = name
;
1774 reorder_insns (label
, label
, PREV_INSN (q
));
1775 delete_insn (table
);
1778 /* If this was a conditional jump, we need to also delete
1779 the insn that set cc0. */
1780 if (HAVE_cc0
&& any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1785 /* Unconditional jumps with side-effects (i.e. which we can't just delete
1786 together with the barrier) should never have a fallthru edge. */
1787 else if (JUMP_P (q
) && any_uncondjump_p (q
))
1790 /* Selectively unlink the sequence. */
1791 if (q
!= PREV_INSN (BB_HEAD (c
)))
1792 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1794 e
->flags
|= EDGE_FALLTHRU
;
1797 /* Should move basic block BB after basic block AFTER. NIY. */
1800 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1801 basic_block after ATTRIBUTE_UNUSED
)
1806 /* Locate the last bb in the same partition as START_BB. */
1809 last_bb_in_partition (basic_block start_bb
)
1812 FOR_BB_BETWEEN (bb
, start_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
1814 if (BB_PARTITION (start_bb
) != BB_PARTITION (bb
->next_bb
))
1817 /* Return bb before the exit block. */
1821 /* Split a (typically critical) edge. Return the new block.
1822 The edge must not be abnormal.
1824 ??? The code generally expects to be called on critical edges.
1825 The case of a block ending in an unconditional jump to a
1826 block with multiple predecessors is not handled optimally. */
1829 rtl_split_edge (edge edge_in
)
1831 basic_block bb
, new_bb
;
1834 /* Abnormal edges cannot be split. */
1835 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1837 /* We are going to place the new block in front of edge destination.
1838 Avoid existence of fallthru predecessors. */
1839 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1841 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1844 force_nonfallthru (e
);
1847 /* Create the basic block note. */
1848 if (edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1849 before
= BB_HEAD (edge_in
->dest
);
1853 /* If this is a fall through edge to the exit block, the blocks might be
1854 not adjacent, and the right place is after the source. */
1855 if ((edge_in
->flags
& EDGE_FALLTHRU
)
1856 && edge_in
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1858 before
= NEXT_INSN (BB_END (edge_in
->src
));
1859 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1860 BB_COPY_PARTITION (bb
, edge_in
->src
);
1864 if (edge_in
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1866 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1867 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1871 basic_block after
= edge_in
->dest
->prev_bb
;
1872 /* If this is post-bb reordering, and the edge crosses a partition
1873 boundary, the new block needs to be inserted in the bb chain
1874 at the end of the src partition (since we put the new bb into
1875 that partition, see below). Otherwise we may end up creating
1876 an extra partition crossing in the chain, which is illegal.
1877 It can't go after the src, because src may have a fall-through
1878 to a different block. */
1879 if (crtl
->bb_reorder_complete
1880 && (edge_in
->flags
& EDGE_CROSSING
))
1882 after
= last_bb_in_partition (edge_in
->src
);
1883 before
= get_last_bb_insn (after
);
1884 /* The instruction following the last bb in partition should
1885 be a barrier, since it cannot end in a fall-through. */
1886 gcc_checking_assert (BARRIER_P (before
));
1887 before
= NEXT_INSN (before
);
1889 bb
= create_basic_block (before
, NULL
, after
);
1890 /* Put the split bb into the src partition, to avoid creating
1891 a situation where a cold bb dominates a hot bb, in the case
1892 where src is cold and dest is hot. The src will dominate
1893 the new bb (whereas it might not have dominated dest). */
1894 BB_COPY_PARTITION (bb
, edge_in
->src
);
1898 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1900 /* Can't allow a region crossing edge to be fallthrough. */
1901 if (BB_PARTITION (bb
) != BB_PARTITION (edge_in
->dest
)
1902 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1904 new_bb
= force_nonfallthru (single_succ_edge (bb
));
1905 gcc_assert (!new_bb
);
1908 /* For non-fallthru edges, we must adjust the predecessor's
1909 jump instruction to target our new block. */
1910 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1912 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1913 gcc_assert (redirected
);
1917 if (edge_in
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1919 /* For asm goto even splitting of fallthru edge might
1920 need insn patching, as other labels might point to the
1922 rtx_insn
*last
= BB_END (edge_in
->src
);
1925 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1926 && (extract_asm_operands (PATTERN (last
))
1927 || JUMP_LABEL (last
) == before
)
1928 && patch_jump_insn (last
, before
, bb
))
1929 df_set_bb_dirty (edge_in
->src
);
1931 redirect_edge_succ (edge_in
, bb
);
1937 /* Queue instructions for insertion on an edge between two basic blocks.
1938 The new instructions and basic blocks (if any) will not appear in the
1939 CFG until commit_edge_insertions is called. */
1942 insert_insn_on_edge (rtx pattern
, edge e
)
1944 /* We cannot insert instructions on an abnormal critical edge.
1945 It will be easier to find the culprit if we die now. */
1946 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1948 if (e
->insns
.r
== NULL_RTX
)
1951 push_to_sequence (e
->insns
.r
);
1953 emit_insn (pattern
);
1955 e
->insns
.r
= get_insns ();
1959 /* Update the CFG for the instructions queued on edge E. */
1962 commit_one_edge_insertion (edge e
)
1964 rtx_insn
*before
= NULL
, *after
= NULL
, *insns
, *tmp
, *last
;
1967 /* Pull the insns off the edge now since the edge might go away. */
1971 /* Figure out where to put these insns. If the destination has
1972 one predecessor, insert there. Except for the exit block. */
1973 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1977 /* Get the location correct wrt a code label, and "nice" wrt
1978 a basic block note, and before everything else. */
1981 tmp
= NEXT_INSN (tmp
);
1982 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1983 tmp
= NEXT_INSN (tmp
);
1984 if (tmp
== BB_HEAD (bb
))
1987 after
= PREV_INSN (tmp
);
1989 after
= get_last_insn ();
1992 /* If the source has one successor and the edge is not abnormal,
1993 insert there. Except for the entry block.
1994 Don't do this if the predecessor ends in a jump other than
1995 unconditional simple jump. E.g. for asm goto that points all
1996 its labels at the fallthru basic block, we can't insert instructions
1997 before the asm goto, as the asm goto can have various of side effects,
1998 and can't emit instructions after the asm goto, as it must end
2000 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
2001 && single_succ_p (e
->src
)
2002 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2003 && (!JUMP_P (BB_END (e
->src
))
2004 || simplejump_p (BB_END (e
->src
))))
2008 /* It is possible to have a non-simple jump here. Consider a target
2009 where some forms of unconditional jumps clobber a register. This
2010 happens on the fr30 for example.
2012 We know this block has a single successor, so we can just emit
2013 the queued insns before the jump. */
2014 if (JUMP_P (BB_END (bb
)))
2015 before
= BB_END (bb
);
2018 /* We'd better be fallthru, or we've lost track of what's what. */
2019 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
2021 after
= BB_END (bb
);
2025 /* Otherwise we must split the edge. */
2028 bb
= split_edge (e
);
2030 /* If E crossed a partition boundary, we needed to make bb end in
2031 a region-crossing jump, even though it was originally fallthru. */
2032 if (JUMP_P (BB_END (bb
)))
2033 before
= BB_END (bb
);
2035 after
= BB_END (bb
);
2038 /* Now that we've found the spot, do the insertion. */
2041 emit_insn_before_noloc (insns
, before
, bb
);
2042 last
= prev_nonnote_insn (before
);
2045 last
= emit_insn_after_noloc (insns
, after
, bb
);
2047 if (returnjump_p (last
))
2049 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2050 This is not currently a problem because this only happens
2051 for the (single) epilogue, which already has a fallthru edge
2054 e
= single_succ_edge (bb
);
2055 gcc_assert (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
2056 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
2058 e
->flags
&= ~EDGE_FALLTHRU
;
2059 emit_barrier_after (last
);
2062 delete_insn (before
);
2065 gcc_assert (!JUMP_P (last
));
2068 /* Update the CFG for all queued instructions. */
2071 commit_edge_insertions (void)
2075 /* Optimization passes that invoke this routine can cause hot blocks
2076 previously reached by both hot and cold blocks to become dominated only
2077 by cold blocks. This will cause the verification below to fail,
2078 and lead to now cold code in the hot section. In some cases this
2079 may only be visible after newly unreachable blocks are deleted,
2080 which will be done by fixup_partitions. */
2081 fixup_partitions ();
2083 checking_verify_flow_info ();
2085 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR_FOR_FN (cfun
),
2086 EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
2091 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2093 commit_one_edge_insertion (e
);
2098 /* Print out RTL-specific basic block information (live information
2099 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
2100 documented in dumpfile.h. */
2103 rtl_dump_bb (FILE *outf
, basic_block bb
, int indent
, dump_flags_t flags
)
2107 s_indent
= (char *) alloca ((size_t) indent
+ 1);
2108 memset (s_indent
, ' ', (size_t) indent
);
2109 s_indent
[indent
] = '\0';
2111 if (df
&& (flags
& TDF_DETAILS
))
2113 df_dump_top (bb
, outf
);
2117 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
2119 rtx_insn
*last
= BB_END (bb
);
2121 last
= NEXT_INSN (last
);
2122 for (rtx_insn
*insn
= BB_HEAD (bb
); insn
!= last
; insn
= NEXT_INSN (insn
))
2124 if (flags
& TDF_DETAILS
)
2125 df_dump_insn_top (insn
, outf
);
2126 if (! (flags
& TDF_SLIM
))
2127 print_rtl_single (outf
, insn
);
2129 dump_insn_slim (outf
, insn
);
2130 if (flags
& TDF_DETAILS
)
2131 df_dump_insn_bottom (insn
, outf
);
2135 if (df
&& (flags
& TDF_DETAILS
))
2137 df_dump_bottom (bb
, outf
);
2143 /* Like dump_function_to_file, but for RTL. Print out dataflow information
2144 for the start of each basic block. FLAGS are the TDF_* masks documented
2148 print_rtl_with_bb (FILE *outf
, const rtx_insn
*rtx_first
, dump_flags_t flags
)
2150 const rtx_insn
*tmp_rtx
;
2152 fprintf (outf
, "(nil)\n");
2155 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
2156 int max_uid
= get_max_uid ();
2157 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
2158 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
2159 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
2162 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
2163 insns, but the CFG is not maintained so the basic block info
2164 is not reliable. Therefore it's omitted from the dumps. */
2165 if (! (cfun
->curr_properties
& PROP_cfg
))
2166 flags
&= ~TDF_BLOCKS
;
2169 df_dump_start (outf
);
2171 if (flags
& TDF_BLOCKS
)
2173 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2177 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
2178 end
[INSN_UID (BB_END (bb
))] = bb
;
2179 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
2181 enum bb_state state
= IN_MULTIPLE_BB
;
2183 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
2185 in_bb_p
[INSN_UID (x
)] = state
;
2187 if (x
== BB_END (bb
))
2193 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
2195 if (flags
& TDF_BLOCKS
)
2197 bb
= start
[INSN_UID (tmp_rtx
)];
2200 dump_bb_info (outf
, bb
, 0, dump_flags
, true, false);
2201 if (df
&& (flags
& TDF_DETAILS
))
2202 df_dump_top (bb
, outf
);
2205 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
2206 && !NOTE_P (tmp_rtx
)
2207 && !BARRIER_P (tmp_rtx
))
2208 fprintf (outf
, ";; Insn is not within a basic block\n");
2209 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
2210 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
2213 if (flags
& TDF_DETAILS
)
2214 df_dump_insn_top (tmp_rtx
, outf
);
2215 if (! (flags
& TDF_SLIM
))
2216 print_rtl_single (outf
, tmp_rtx
);
2218 dump_insn_slim (outf
, tmp_rtx
);
2219 if (flags
& TDF_DETAILS
)
2220 df_dump_insn_bottom (tmp_rtx
, outf
);
2222 if (flags
& TDF_BLOCKS
)
2224 bb
= end
[INSN_UID (tmp_rtx
)];
2227 dump_bb_info (outf
, bb
, 0, dump_flags
, false, true);
2228 if (df
&& (flags
& TDF_DETAILS
))
2229 df_dump_bottom (bb
, outf
);
2241 /* Update the branch probability of BB if a REG_BR_PROB is present. */
2244 update_br_prob_note (basic_block bb
)
2247 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
2248 if (!JUMP_P (BB_END (bb
)) || !BRANCH_EDGE (bb
)->probability
.initialized_p ())
2252 rtx
*note_link
, this_rtx
;
2254 note_link
= ®_NOTES (BB_END (bb
));
2255 for (this_rtx
= *note_link
; this_rtx
; this_rtx
= XEXP (this_rtx
, 1))
2256 if (this_rtx
== note
)
2258 *note_link
= XEXP (this_rtx
, 1);
2265 || XINT (note
, 0) == BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ())
2267 XINT (note
, 0) = BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ();
2270 /* Get the last insn associated with block BB (that includes barriers and
2271 tablejumps after BB). */
2273 get_last_bb_insn (basic_block bb
)
2275 rtx_jump_table_data
*table
;
2277 rtx_insn
*end
= BB_END (bb
);
2279 /* Include any jump table following the basic block. */
2280 if (tablejump_p (end
, NULL
, &table
))
2283 /* Include any barriers that may follow the basic block. */
2284 tmp
= next_nonnote_insn_bb (end
);
2285 while (tmp
&& BARRIER_P (tmp
))
2288 tmp
= next_nonnote_insn_bb (end
);
2294 /* Add all BBs reachable from entry via hot paths into the SET. */
2297 find_bbs_reachable_by_hot_paths (hash_set
<basic_block
> *set
)
2299 auto_vec
<basic_block
, 64> worklist
;
2301 set
->add (ENTRY_BLOCK_PTR_FOR_FN (cfun
));
2302 worklist
.safe_push (ENTRY_BLOCK_PTR_FOR_FN (cfun
));
2304 while (worklist
.length () > 0)
2306 basic_block bb
= worklist
.pop ();
2310 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2311 if (BB_PARTITION (e
->dest
) != BB_COLD_PARTITION
2312 && !set
->add (e
->dest
))
2313 worklist
.safe_push (e
->dest
);
2317 /* Sanity check partition hotness to ensure that basic blocks in
2318 Â the cold partition don't dominate basic blocks in the hot partition.
2319 If FLAG_ONLY is true, report violations as errors. Otherwise
2320 re-mark the dominated blocks as cold, since this is run after
2321 cfg optimizations that may make hot blocks previously reached
2322 by both hot and cold blocks now only reachable along cold paths. */
2324 static vec
<basic_block
>
2325 find_partition_fixes (bool flag_only
)
2328 vec
<basic_block
> bbs_in_cold_partition
= vNULL
;
2329 vec
<basic_block
> bbs_to_fix
= vNULL
;
2330 hash_set
<basic_block
> set
;
2332 /* Callers check this. */
2333 gcc_checking_assert (crtl
->has_bb_partition
);
2335 find_bbs_reachable_by_hot_paths (&set
);
2337 FOR_EACH_BB_FN (bb
, cfun
)
2338 if (!set
.contains (bb
)
2339 && BB_PARTITION (bb
) != BB_COLD_PARTITION
)
2342 error ("non-cold basic block %d reachable only "
2343 "by paths crossing the cold partition", bb
->index
);
2345 BB_SET_PARTITION (bb
, BB_COLD_PARTITION
);
2346 bbs_to_fix
.safe_push (bb
);
2347 bbs_in_cold_partition
.safe_push (bb
);
2353 /* Perform cleanup on the hot/cold bb partitioning after optimization
2354 passes that modify the cfg. */
2357 fixup_partitions (void)
2361 if (!crtl
->has_bb_partition
)
2364 /* Delete any blocks that became unreachable and weren't
2365 already cleaned up, for example during edge forwarding
2366 and convert_jumps_to_returns. This will expose more
2367 opportunities for fixing the partition boundaries here.
2368 Also, the calculation of the dominance graph during verification
2369 will assert if there are unreachable nodes. */
2370 delete_unreachable_blocks ();
2372 /* If there are partitions, do a sanity check on them: A basic block in
2373 Â a cold partition cannot dominate a basic block in a hot partition.
2374 Fixup any that now violate this requirement, as a result of edge
2375 forwarding and unreachable block deletion. Â */
2376 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (false);
2378 /* Do the partition fixup after all necessary blocks have been converted to
2379 cold, so that we only update the region crossings the minimum number of
2380 places, which can require forcing edges to be non fallthru. */
2381 while (! bbs_to_fix
.is_empty ())
2383 bb
= bbs_to_fix
.pop ();
2384 fixup_new_cold_bb (bb
);
2388 /* Verify, in the basic block chain, that there is at most one switch
2389 between hot/cold partitions. This condition will not be true until
2390 after reorder_basic_blocks is called. */
2393 verify_hot_cold_block_grouping (void)
2397 bool switched_sections
= false;
2398 int current_partition
= BB_UNPARTITIONED
;
2400 /* Even after bb reordering is complete, we go into cfglayout mode
2401 again (in compgoto). Ensure we don't call this before going back
2402 into linearized RTL when any layout fixes would have been committed. */
2403 if (!crtl
->bb_reorder_complete
2404 || current_ir_type () != IR_RTL_CFGRTL
)
2407 FOR_EACH_BB_FN (bb
, cfun
)
2409 if (current_partition
!= BB_UNPARTITIONED
2410 && BB_PARTITION (bb
) != current_partition
)
2412 if (switched_sections
)
2414 error ("multiple hot/cold transitions found (bb %i)",
2419 switched_sections
= true;
2421 if (!crtl
->has_bb_partition
)
2422 error ("partition found but function partition flag not set");
2424 current_partition
= BB_PARTITION (bb
);
2431 /* Perform several checks on the edges out of each block, such as
2432 the consistency of the branch probabilities, the correctness
2433 of hot/cold partition crossing edges, and the number of expected
2434 successor edges. Also verify that the dominance relationship
2435 between hot/cold blocks is sane. */
2438 rtl_verify_edges (void)
2443 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2445 int n_fallthru
= 0, n_branch
= 0, n_abnormal_call
= 0, n_sibcall
= 0;
2446 int n_eh
= 0, n_abnormal
= 0;
2447 edge e
, fallthru
= NULL
;
2450 bool has_crossing_edge
= false;
2452 if (JUMP_P (BB_END (bb
))
2453 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
2454 && EDGE_COUNT (bb
->succs
) >= 2
2455 && any_condjump_p (BB_END (bb
)))
2457 if (!BRANCH_EDGE (bb
)->probability
.initialized_p ())
2459 if (profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2461 error ("verify_flow_info: "
2462 "REG_BR_PROB is set but cfg probability is not");
2466 else if (XINT (note
, 0)
2467 != BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ()
2468 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2470 error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
2472 BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ());
2477 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2481 if (e
->flags
& EDGE_FALLTHRU
)
2482 n_fallthru
++, fallthru
= e
;
2484 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
2485 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2486 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
));
2487 has_crossing_edge
|= is_crossing
;
2488 if (e
->flags
& EDGE_CROSSING
)
2492 error ("EDGE_CROSSING incorrectly set across same section");
2495 if (e
->flags
& EDGE_FALLTHRU
)
2497 error ("fallthru edge crosses section boundary in bb %i",
2501 if (e
->flags
& EDGE_EH
)
2503 error ("EH edge crosses section boundary in bb %i",
2507 if (JUMP_P (BB_END (bb
)) && !CROSSING_JUMP_P (BB_END (bb
)))
2509 error ("No region crossing jump at section boundary in bb %i",
2514 else if (is_crossing
)
2516 error ("EDGE_CROSSING missing across section boundary");
2520 if ((e
->flags
& ~(EDGE_DFS_BACK
2522 | EDGE_IRREDUCIBLE_LOOP
2525 | EDGE_PRESERVE
)) == 0)
2528 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2531 if (e
->flags
& EDGE_SIBCALL
)
2534 if (e
->flags
& EDGE_EH
)
2537 if (e
->flags
& EDGE_ABNORMAL
)
2541 if (!has_crossing_edge
2542 && JUMP_P (BB_END (bb
))
2543 && CROSSING_JUMP_P (BB_END (bb
)))
2545 print_rtl_with_bb (stderr
, get_insns (), TDF_BLOCKS
| TDF_DETAILS
);
2546 error ("Region crossing jump across same section in bb %i",
2551 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2553 error ("missing REG_EH_REGION note at the end of bb %i", bb
->index
);
2558 error ("too many exception handling edges in bb %i", bb
->index
);
2562 && (!JUMP_P (BB_END (bb
))
2563 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2564 || any_condjump_p (BB_END (bb
))))))
2566 error ("too many outgoing branch edges from bb %i", bb
->index
);
2569 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2571 error ("fallthru edge after unconditional jump in bb %i", bb
->index
);
2574 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2576 error ("wrong number of branch edges after unconditional jump"
2577 " in bb %i", bb
->index
);
2580 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2581 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2583 error ("wrong amount of branch edges after conditional jump"
2584 " in bb %i", bb
->index
);
2587 if (n_abnormal_call
&& !CALL_P (BB_END (bb
)))
2589 error ("abnormal call edges for non-call insn in bb %i", bb
->index
);
2592 if (n_sibcall
&& !CALL_P (BB_END (bb
)))
2594 error ("sibcall edges for non-call insn in bb %i", bb
->index
);
2597 if (n_abnormal
> n_eh
2598 && !(CALL_P (BB_END (bb
))
2599 && n_abnormal
== n_abnormal_call
+ n_sibcall
)
2600 && (!JUMP_P (BB_END (bb
))
2601 || any_condjump_p (BB_END (bb
))
2602 || any_uncondjump_p (BB_END (bb
))))
2604 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2609 /* If there are partitions, do a sanity check on them: A basic block in
2610 Â a cold partition cannot dominate a basic block in a hot partition. Â */
2611 if (crtl
->has_bb_partition
&& !err
)
2613 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (true);
2614 err
= !bbs_to_fix
.is_empty ();
2621 /* Checks on the instructions within blocks. Currently checks that each
2622 block starts with a basic block note, and that basic block notes and
2623 control flow jumps are not found in the middle of the block. */
2626 rtl_verify_bb_insns (void)
2632 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2634 /* Now check the header of basic
2635 block. It ought to contain optional CODE_LABEL followed
2636 by NOTE_BASIC_BLOCK. */
2640 if (BB_END (bb
) == x
)
2642 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2650 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2652 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2657 if (BB_END (bb
) == x
)
2658 /* Do checks for empty blocks here. */
2661 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2663 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2665 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2666 INSN_UID (x
), bb
->index
);
2670 if (x
== BB_END (bb
))
2673 if (control_flow_insn_p (x
))
2675 error ("in basic block %d:", bb
->index
);
2676 fatal_insn ("flow control insn inside a basic block", x
);
2685 /* Verify that block pointers for instructions in basic blocks, headers and
2686 footers are set appropriately. */
2689 rtl_verify_bb_pointers (void)
2694 /* Check the general integrity of the basic blocks. */
2695 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2699 if (!(bb
->flags
& BB_RTL
))
2701 error ("BB_RTL flag not set for block %d", bb
->index
);
2705 FOR_BB_INSNS (bb
, insn
)
2706 if (BLOCK_FOR_INSN (insn
) != bb
)
2708 error ("insn %d basic block pointer is %d, should be %d",
2710 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
2715 for (insn
= BB_HEADER (bb
); insn
; insn
= NEXT_INSN (insn
))
2716 if (!BARRIER_P (insn
)
2717 && BLOCK_FOR_INSN (insn
) != NULL
)
2719 error ("insn %d in header of bb %d has non-NULL basic block",
2720 INSN_UID (insn
), bb
->index
);
2723 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2724 if (!BARRIER_P (insn
)
2725 && BLOCK_FOR_INSN (insn
) != NULL
)
2727 error ("insn %d in footer of bb %d has non-NULL basic block",
2728 INSN_UID (insn
), bb
->index
);
2737 /* Verify the CFG and RTL consistency common for both underlying RTL and
2740 Currently it does following checks:
2742 - overlapping of basic blocks
2743 - insns with wrong BLOCK_FOR_INSN pointers
2744 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2745 - tails of basic blocks (ensure that boundary is necessary)
2746 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2747 and NOTE_INSN_BASIC_BLOCK
2748 - verify that no fall_thru edge crosses hot/cold partition boundaries
2749 - verify that there are no pending RTL branch predictions
2750 - verify that hot blocks are not dominated by cold blocks
2752 In future it can be extended check a lot of other stuff as well
2753 (reachability of basic blocks, life information, etc. etc.). */
2756 rtl_verify_flow_info_1 (void)
2760 err
|= rtl_verify_bb_pointers ();
2762 err
|= rtl_verify_bb_insns ();
2764 err
|= rtl_verify_edges ();
2769 /* Walk the instruction chain and verify that bb head/end pointers
2770 are correct, and that instructions are in exactly one bb and have
2771 correct block pointers. */
2774 rtl_verify_bb_insn_chain (void)
2779 rtx_insn
*last_head
= get_last_insn ();
2780 basic_block
*bb_info
;
2781 const int max_uid
= get_max_uid ();
2783 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2785 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2787 rtx_insn
*head
= BB_HEAD (bb
);
2788 rtx_insn
*end
= BB_END (bb
);
2790 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2792 /* Verify the end of the basic block is in the INSN chain. */
2796 /* And that the code outside of basic blocks has NULL bb field. */
2798 && BLOCK_FOR_INSN (x
) != NULL
)
2800 error ("insn %d outside of basic blocks has non-NULL bb field",
2808 error ("end insn %d for block %d not found in the insn stream",
2809 INSN_UID (end
), bb
->index
);
2813 /* Work backwards from the end to the head of the basic block
2814 to verify the head is in the RTL chain. */
2815 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2817 /* While walking over the insn chain, verify insns appear
2818 in only one basic block. */
2819 if (bb_info
[INSN_UID (x
)] != NULL
)
2821 error ("insn %d is in multiple basic blocks (%d and %d)",
2822 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2826 bb_info
[INSN_UID (x
)] = bb
;
2833 error ("head insn %d for block %d not found in the insn stream",
2834 INSN_UID (head
), bb
->index
);
2838 last_head
= PREV_INSN (x
);
2841 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2843 /* Check that the code before the first basic block has NULL
2846 && BLOCK_FOR_INSN (x
) != NULL
)
2848 error ("insn %d outside of basic blocks has non-NULL bb field",
2858 /* Verify that fallthru edges point to adjacent blocks in layout order and
2859 that barriers exist after non-fallthru blocks. */
2862 rtl_verify_fallthru (void)
2867 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2871 e
= find_fallthru_edge (bb
->succs
);
2876 /* Ensure existence of barrier in BB with no fallthru edges. */
2877 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2879 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2881 error ("missing barrier after block %i", bb
->index
);
2885 if (BARRIER_P (insn
))
2889 else if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2890 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2894 if (e
->src
->next_bb
!= e
->dest
)
2897 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2898 e
->src
->index
, e
->dest
->index
);
2902 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2903 insn
= NEXT_INSN (insn
))
2904 if (BARRIER_P (insn
) || INSN_P (insn
))
2906 error ("verify_flow_info: Incorrect fallthru %i->%i",
2907 e
->src
->index
, e
->dest
->index
);
2908 fatal_insn ("wrong insn in the fallthru edge", insn
);
2917 /* Verify that blocks are laid out in consecutive order. While walking the
2918 instructions, verify that all expected instructions are inside the basic
2919 blocks, and that all returns are followed by barriers. */
2922 rtl_verify_bb_layout (void)
2928 rtx_insn
* const rtx_first
= get_insns ();
2929 basic_block last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
), curr_bb
= NULL
;
2932 last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
2934 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2936 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2938 bb
= NOTE_BASIC_BLOCK (x
);
2941 if (bb
!= last_bb_seen
->next_bb
)
2942 internal_error ("basic blocks not laid down consecutively");
2944 curr_bb
= last_bb_seen
= bb
;
2949 switch (GET_CODE (x
))
2956 /* An ADDR_VEC is placed outside any basic block. */
2958 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2961 /* But in any case, non-deletable labels can appear anywhere. */
2965 fatal_insn ("insn outside basic block", x
);
2970 && returnjump_p (x
) && ! condjump_p (x
)
2971 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2972 fatal_insn ("return not followed by barrier", x
);
2974 if (curr_bb
&& x
== BB_END (curr_bb
))
2978 if (num_bb_notes
!= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
)
2980 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2981 num_bb_notes
, n_basic_blocks_for_fn (cfun
));
2986 /* Verify the CFG and RTL consistency common for both underlying RTL and
2987 cfglayout RTL, plus consistency checks specific to linearized RTL mode.
2989 Currently it does following checks:
2990 - all checks of rtl_verify_flow_info_1
2991 - test head/end pointers
2992 - check that blocks are laid out in consecutive order
2993 - check that all insns are in the basic blocks
2994 (except the switch handling code, barriers and notes)
2995 - check that all returns are followed by barriers
2996 - check that all fallthru edge points to the adjacent blocks
2997 - verify that there is a single hot/cold partition boundary after bbro */
3000 rtl_verify_flow_info (void)
3004 err
|= rtl_verify_flow_info_1 ();
3006 err
|= rtl_verify_bb_insn_chain ();
3008 err
|= rtl_verify_fallthru ();
3010 err
|= rtl_verify_bb_layout ();
3012 err
|= verify_hot_cold_block_grouping ();
3017 /* Assume that the preceding pass has possibly eliminated jump instructions
3018 or converted the unconditional jumps. Eliminate the edges from CFG.
3019 Return true if any edges are eliminated. */
3022 purge_dead_edges (basic_block bb
)
3025 rtx_insn
*insn
= BB_END (bb
);
3027 bool purged
= false;
3031 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
3033 insn
= PREV_INSN (insn
);
3034 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
3036 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
3037 if (NONJUMP_INSN_P (insn
)
3038 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
3042 if (! may_trap_p (PATTERN (insn
))
3043 || ((eqnote
= find_reg_equal_equiv_note (insn
))
3044 && ! may_trap_p (XEXP (eqnote
, 0))))
3045 remove_note (insn
, note
);
3048 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
3049 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3051 bool remove
= false;
3053 /* There are three types of edges we need to handle correctly here: EH
3054 edges, abnormal call EH edges, and abnormal call non-EH edges. The
3055 latter can appear when nonlocal gotos are used. */
3056 if (e
->flags
& EDGE_ABNORMAL_CALL
)
3060 else if (can_nonlocal_goto (insn
))
3062 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3064 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
3069 else if (e
->flags
& EDGE_EH
)
3070 remove
= !can_throw_internal (insn
);
3075 df_set_bb_dirty (bb
);
3088 /* We do care only about conditional jumps and simplejumps. */
3089 if (!any_condjump_p (insn
)
3090 && !returnjump_p (insn
)
3091 && !simplejump_p (insn
))
3094 /* Branch probability/prediction notes are defined only for
3095 condjumps. We've possibly turned condjump into simplejump. */
3096 if (simplejump_p (insn
))
3098 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3100 remove_note (insn
, note
);
3101 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
3102 remove_note (insn
, note
);
3105 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3107 /* Avoid abnormal flags to leak from computed jumps turned
3108 into simplejumps. */
3110 e
->flags
&= ~EDGE_ABNORMAL
;
3112 /* See if this edge is one we should keep. */
3113 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
3114 /* A conditional jump can fall through into the next
3115 block, so we should keep the edge. */
3120 else if (e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
3121 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
3122 /* If the destination block is the target of the jump,
3128 else if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
3129 && returnjump_p (insn
))
3130 /* If the destination block is the exit block, and this
3131 instruction is a return, then keep the edge. */
3136 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3137 /* Keep the edges that correspond to exceptions thrown by
3138 this instruction and rematerialize the EDGE_ABNORMAL
3139 flag we just cleared above. */
3141 e
->flags
|= EDGE_ABNORMAL
;
3146 /* We do not need this edge. */
3147 df_set_bb_dirty (bb
);
3152 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
3156 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
3161 /* Redistribute probabilities. */
3162 if (single_succ_p (bb
))
3164 single_succ_edge (bb
)->probability
= profile_probability::always ();
3168 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3172 b
= BRANCH_EDGE (bb
);
3173 f
= FALLTHRU_EDGE (bb
);
3174 b
->probability
= profile_probability::from_reg_br_prob_note
3176 f
->probability
= b
->probability
.invert ();
3181 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
3183 /* First, there should not be any EH or ABCALL edges resulting
3184 from non-local gotos and the like. If there were, we shouldn't
3185 have created the sibcall in the first place. Second, there
3186 should of course never have been a fallthru edge. */
3187 gcc_assert (single_succ_p (bb
));
3188 gcc_assert (single_succ_edge (bb
)->flags
3189 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
3194 /* If we don't see a jump insn, we don't know exactly why the block would
3195 have been broken at this point. Look for a simple, non-fallthru edge,
3196 as these are only created by conditional branches. If we find such an
3197 edge we know that there used to be a jump here and can then safely
3198 remove all non-fallthru edges. */
3200 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3201 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
3210 /* Remove all but the fake and fallthru edges. The fake edge may be
3211 the only successor for this block in the case of noreturn
3213 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3215 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
3217 df_set_bb_dirty (bb
);
3225 gcc_assert (single_succ_p (bb
));
3227 single_succ_edge (bb
)->probability
= profile_probability::always ();
3230 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
3235 /* Search all basic blocks for potentially dead edges and purge them. Return
3236 true if some edge has been eliminated. */
3239 purge_all_dead_edges (void)
3244 FOR_EACH_BB_FN (bb
, cfun
)
3246 bool purged_here
= purge_dead_edges (bb
);
3248 purged
|= purged_here
;
3254 /* This is used by a few passes that emit some instructions after abnormal
3255 calls, moving the basic block's end, while they in fact do want to emit
3256 them on the fallthru edge. Look for abnormal call edges, find backward
3257 the call in the block and insert the instructions on the edge instead.
3259 Similarly, handle instructions throwing exceptions internally.
3261 Return true when instructions have been found and inserted on edges. */
3264 fixup_abnormal_edges (void)
3266 bool inserted
= false;
3269 FOR_EACH_BB_FN (bb
, cfun
)
3274 /* Look for cases we are interested in - calls or instructions causing
3276 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3277 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
3278 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
3279 == (EDGE_ABNORMAL
| EDGE_EH
)))
3282 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
3286 /* Get past the new insns generated. Allow notes, as the insns
3287 may be already deleted. */
3289 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
3290 && !can_throw_internal (insn
)
3291 && insn
!= BB_HEAD (bb
))
3292 insn
= PREV_INSN (insn
);
3294 if (CALL_P (insn
) || can_throw_internal (insn
))
3296 rtx_insn
*stop
, *next
;
3298 e
= find_fallthru_edge (bb
->succs
);
3300 stop
= NEXT_INSN (BB_END (bb
));
3303 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
3305 next
= NEXT_INSN (insn
);
3310 /* Sometimes there's still the return value USE.
3311 If it's placed after a trapping call (i.e. that
3312 call is the last insn anyway), we have no fallthru
3313 edge. Simply delete this use and don't try to insert
3314 on the non-existent edge. */
3315 if (GET_CODE (PATTERN (insn
)) != USE
)
3317 /* We're not deleting it, we're moving it. */
3318 insn
->set_undeleted ();
3319 SET_PREV_INSN (insn
) = NULL_RTX
;
3320 SET_NEXT_INSN (insn
) = NULL_RTX
;
3322 insert_insn_on_edge (insn
, e
);
3326 else if (!BARRIER_P (insn
))
3327 set_block_for_insn (insn
, NULL
);
3331 /* It may be that we don't find any trapping insn. In this
3332 case we discovered quite late that the insn that had been
3333 marked as can_throw_internal in fact couldn't trap at all.
3334 So we should in fact delete the EH edges out of the block. */
3336 purge_dead_edges (bb
);
3343 /* Cut the insns from FIRST to LAST out of the insns stream. */
3346 unlink_insn_chain (rtx_insn
*first
, rtx_insn
*last
)
3348 rtx_insn
*prevfirst
= PREV_INSN (first
);
3349 rtx_insn
*nextlast
= NEXT_INSN (last
);
3351 SET_PREV_INSN (first
) = NULL
;
3352 SET_NEXT_INSN (last
) = NULL
;
3354 SET_NEXT_INSN (prevfirst
) = nextlast
;
3356 SET_PREV_INSN (nextlast
) = prevfirst
;
3358 set_last_insn (prevfirst
);
3360 set_first_insn (nextlast
);
3364 /* Skip over inter-block insns occurring after BB which are typically
3365 associated with BB (e.g., barriers). If there are any such insns,
3366 we return the last one. Otherwise, we return the end of BB. */
3369 skip_insns_after_block (basic_block bb
)
3371 rtx_insn
*insn
, *last_insn
, *next_head
, *prev
;
3374 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3375 next_head
= BB_HEAD (bb
->next_bb
);
3377 for (last_insn
= insn
= BB_END (bb
); (insn
= NEXT_INSN (insn
)) != 0; )
3379 if (insn
== next_head
)
3382 switch (GET_CODE (insn
))
3389 switch (NOTE_KIND (insn
))
3391 case NOTE_INSN_BLOCK_END
:
3401 if (NEXT_INSN (insn
)
3402 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
3404 insn
= NEXT_INSN (insn
);
3417 /* It is possible to hit contradictory sequence. For instance:
3423 Where barrier belongs to jump_insn, but the note does not. This can be
3424 created by removing the basic block originally following
3425 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
3427 for (insn
= last_insn
; insn
!= BB_END (bb
); insn
= prev
)
3429 prev
= PREV_INSN (insn
);
3431 switch (NOTE_KIND (insn
))
3433 case NOTE_INSN_BLOCK_END
:
3436 case NOTE_INSN_DELETED
:
3437 case NOTE_INSN_DELETED_LABEL
:
3438 case NOTE_INSN_DELETED_DEBUG_LABEL
:
3441 reorder_insns (insn
, insn
, last_insn
);
3448 /* Locate or create a label for a given basic block. */
3451 label_for_bb (basic_block bb
)
3453 rtx_insn
*label
= BB_HEAD (bb
);
3455 if (!LABEL_P (label
))
3458 fprintf (dump_file
, "Emitting label for block %d\n", bb
->index
);
3460 label
= block_label (bb
);
3466 /* Locate the effective beginning and end of the insn chain for each
3467 block, as defined by skip_insns_after_block above. */
3470 record_effective_endpoints (void)
3472 rtx_insn
*next_insn
;
3476 for (insn
= get_insns ();
3479 && NOTE_KIND (insn
) != NOTE_INSN_BASIC_BLOCK
;
3480 insn
= NEXT_INSN (insn
))
3482 /* No basic blocks at all? */
3485 if (PREV_INSN (insn
))
3486 cfg_layout_function_header
=
3487 unlink_insn_chain (get_insns (), PREV_INSN (insn
));
3489 cfg_layout_function_header
= NULL
;
3491 next_insn
= get_insns ();
3492 FOR_EACH_BB_FN (bb
, cfun
)
3496 if (PREV_INSN (BB_HEAD (bb
)) && next_insn
!= BB_HEAD (bb
))
3497 BB_HEADER (bb
) = unlink_insn_chain (next_insn
,
3498 PREV_INSN (BB_HEAD (bb
)));
3499 end
= skip_insns_after_block (bb
);
3500 if (NEXT_INSN (BB_END (bb
)) && BB_END (bb
) != end
)
3501 BB_FOOTER (bb
) = unlink_insn_chain (NEXT_INSN (BB_END (bb
)), end
);
3502 next_insn
= NEXT_INSN (BB_END (bb
));
3505 cfg_layout_function_footer
= next_insn
;
3506 if (cfg_layout_function_footer
)
3507 cfg_layout_function_footer
= unlink_insn_chain (cfg_layout_function_footer
, get_last_insn ());
3512 const pass_data pass_data_into_cfg_layout_mode
=
3514 RTL_PASS
, /* type */
3515 "into_cfglayout", /* name */
3516 OPTGROUP_NONE
, /* optinfo_flags */
3518 0, /* properties_required */
3519 PROP_cfglayout
, /* properties_provided */
3520 0, /* properties_destroyed */
3521 0, /* todo_flags_start */
3522 0, /* todo_flags_finish */
3525 class pass_into_cfg_layout_mode
: public rtl_opt_pass
3528 pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3529 : rtl_opt_pass (pass_data_into_cfg_layout_mode
, ctxt
)
3532 /* opt_pass methods: */
3533 virtual unsigned int execute (function
*)
3535 cfg_layout_initialize (0);
3539 }; // class pass_into_cfg_layout_mode
3544 make_pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3546 return new pass_into_cfg_layout_mode (ctxt
);
3551 const pass_data pass_data_outof_cfg_layout_mode
=
3553 RTL_PASS
, /* type */
3554 "outof_cfglayout", /* name */
3555 OPTGROUP_NONE
, /* optinfo_flags */
3557 0, /* properties_required */
3558 0, /* properties_provided */
3559 PROP_cfglayout
, /* properties_destroyed */
3560 0, /* todo_flags_start */
3561 0, /* todo_flags_finish */
3564 class pass_outof_cfg_layout_mode
: public rtl_opt_pass
3567 pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3568 : rtl_opt_pass (pass_data_outof_cfg_layout_mode
, ctxt
)
3571 /* opt_pass methods: */
3572 virtual unsigned int execute (function
*);
3574 }; // class pass_outof_cfg_layout_mode
3577 pass_outof_cfg_layout_mode::execute (function
*fun
)
3581 FOR_EACH_BB_FN (bb
, fun
)
3582 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (fun
))
3583 bb
->aux
= bb
->next_bb
;
3585 cfg_layout_finalize ();
3593 make_pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3595 return new pass_outof_cfg_layout_mode (ctxt
);
3599 /* Link the basic blocks in the correct order, compacting the basic
3600 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3601 function also clears the basic block header and footer fields.
3603 This function is usually called after a pass (e.g. tracer) finishes
3604 some transformations while in cfglayout mode. The required sequence
3605 of the basic blocks is in a linked list along the bb->aux field.
3606 This functions re-links the basic block prev_bb and next_bb pointers
3607 accordingly, and it compacts and renumbers the blocks.
3609 FIXME: This currently works only for RTL, but the only RTL-specific
3610 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3611 to GIMPLE a long time ago, but it doesn't relink the basic block
3612 chain. It could do that (to give better initial RTL) if this function
3613 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3616 relink_block_chain (bool stay_in_cfglayout_mode
)
3618 basic_block bb
, prev_bb
;
3621 /* Maybe dump the re-ordered sequence. */
3624 fprintf (dump_file
, "Reordered sequence:\n");
3625 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
, index
=
3628 bb
= (basic_block
) bb
->aux
, index
++)
3630 fprintf (dump_file
, " %i ", index
);
3631 if (get_bb_original (bb
))
3632 fprintf (dump_file
, "duplicate of %i ",
3633 get_bb_original (bb
)->index
);
3634 else if (forwarder_block_p (bb
)
3635 && !LABEL_P (BB_HEAD (bb
)))
3636 fprintf (dump_file
, "compensation ");
3638 fprintf (dump_file
, "bb %i ", bb
->index
);
3642 /* Now reorder the blocks. */
3643 prev_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
3644 bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3645 for (; bb
; prev_bb
= bb
, bb
= (basic_block
) bb
->aux
)
3647 bb
->prev_bb
= prev_bb
;
3648 prev_bb
->next_bb
= bb
;
3650 prev_bb
->next_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
3651 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
= prev_bb
;
3653 /* Then, clean up the aux fields. */
3654 FOR_ALL_BB_FN (bb
, cfun
)
3657 if (!stay_in_cfglayout_mode
)
3658 BB_HEADER (bb
) = BB_FOOTER (bb
) = NULL
;
3661 /* Maybe reset the original copy tables, they are not valid anymore
3662 when we renumber the basic blocks in compact_blocks. If we are
3663 are going out of cfglayout mode, don't re-allocate the tables. */
3664 if (original_copy_tables_initialized_p ())
3665 free_original_copy_tables ();
3666 if (stay_in_cfglayout_mode
)
3667 initialize_original_copy_tables ();
3669 /* Finally, put basic_block_info in the new order. */
3674 /* Given a reorder chain, rearrange the code to match. */
3677 fixup_reorder_chain (void)
3680 rtx_insn
*insn
= NULL
;
3682 if (cfg_layout_function_header
)
3684 set_first_insn (cfg_layout_function_header
);
3685 insn
= cfg_layout_function_header
;
3686 while (NEXT_INSN (insn
))
3687 insn
= NEXT_INSN (insn
);
3690 /* First do the bulk reordering -- rechain the blocks without regard to
3691 the needed changes to jumps and labels. */
3693 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3699 SET_NEXT_INSN (insn
) = BB_HEADER (bb
);
3701 set_first_insn (BB_HEADER (bb
));
3702 SET_PREV_INSN (BB_HEADER (bb
)) = insn
;
3703 insn
= BB_HEADER (bb
);
3704 while (NEXT_INSN (insn
))
3705 insn
= NEXT_INSN (insn
);
3708 SET_NEXT_INSN (insn
) = BB_HEAD (bb
);
3710 set_first_insn (BB_HEAD (bb
));
3711 SET_PREV_INSN (BB_HEAD (bb
)) = insn
;
3715 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
3716 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
3717 while (NEXT_INSN (insn
))
3718 insn
= NEXT_INSN (insn
);
3722 SET_NEXT_INSN (insn
) = cfg_layout_function_footer
;
3723 if (cfg_layout_function_footer
)
3724 SET_PREV_INSN (cfg_layout_function_footer
) = insn
;
3726 while (NEXT_INSN (insn
))
3727 insn
= NEXT_INSN (insn
);
3729 set_last_insn (insn
);
3731 verify_insn_chain ();
3733 /* Now add jumps and labels as needed to match the blocks new
3736 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3739 edge e_fall
, e_taken
, e
;
3740 rtx_insn
*bb_end_insn
;
3741 rtx ret_label
= NULL_RTX
;
3745 if (EDGE_COUNT (bb
->succs
) == 0)
3748 /* Find the old fallthru edge, and another non-EH edge for
3750 e_taken
= e_fall
= NULL
;
3752 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3753 if (e
->flags
& EDGE_FALLTHRU
)
3755 else if (! (e
->flags
& EDGE_EH
))
3758 bb_end_insn
= BB_END (bb
);
3759 if (rtx_jump_insn
*bb_end_jump
= dyn_cast
<rtx_jump_insn
*> (bb_end_insn
))
3761 ret_label
= JUMP_LABEL (bb_end_jump
);
3762 if (any_condjump_p (bb_end_jump
))
3764 /* This might happen if the conditional jump has side
3765 effects and could therefore not be optimized away.
3766 Make the basic block to end with a barrier in order
3767 to prevent rtl_verify_flow_info from complaining. */
3770 gcc_assert (!onlyjump_p (bb_end_jump
)
3771 || returnjump_p (bb_end_jump
)
3772 || (e_taken
->flags
& EDGE_CROSSING
));
3773 emit_barrier_after (bb_end_jump
);
3777 /* If the old fallthru is still next, nothing to do. */
3778 if (bb
->aux
== e_fall
->dest
3779 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3782 /* The degenerated case of conditional jump jumping to the next
3783 instruction can happen for jumps with side effects. We need
3784 to construct a forwarder block and this will be done just
3785 fine by force_nonfallthru below. */
3789 /* There is another special case: if *neither* block is next,
3790 such as happens at the very end of a function, then we'll
3791 need to add a new unconditional jump. Choose the taken
3792 edge based on known or assumed probability. */
3793 else if (bb
->aux
!= e_taken
->dest
)
3795 rtx note
= find_reg_note (bb_end_jump
, REG_BR_PROB
, 0);
3798 && profile_probability::from_reg_br_prob_note
3799 (XINT (note
, 0)) < profile_probability::even ()
3800 && invert_jump (bb_end_jump
,
3802 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3804 : label_for_bb (e_fall
->dest
)), 0))
3806 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3807 gcc_checking_assert (could_fall_through
3808 (e_taken
->src
, e_taken
->dest
));
3809 e_taken
->flags
|= EDGE_FALLTHRU
;
3810 update_br_prob_note (bb
);
3811 e
= e_fall
, e_fall
= e_taken
, e_taken
= e
;
3815 /* If the "jumping" edge is a crossing edge, and the fall
3816 through edge is non-crossing, leave things as they are. */
3817 else if ((e_taken
->flags
& EDGE_CROSSING
)
3818 && !(e_fall
->flags
& EDGE_CROSSING
))
3821 /* Otherwise we can try to invert the jump. This will
3822 basically never fail, however, keep up the pretense. */
3823 else if (invert_jump (bb_end_jump
,
3825 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3827 : label_for_bb (e_fall
->dest
)), 0))
3829 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3830 gcc_checking_assert (could_fall_through
3831 (e_taken
->src
, e_taken
->dest
));
3832 e_taken
->flags
|= EDGE_FALLTHRU
;
3833 update_br_prob_note (bb
);
3834 if (LABEL_NUSES (ret_label
) == 0
3835 && single_pred_p (e_taken
->dest
))
3836 delete_insn (as_a
<rtx_insn
*> (ret_label
));
3840 else if (extract_asm_operands (PATTERN (bb_end_insn
)) != NULL
)
3842 /* If the old fallthru is still next or if
3843 asm goto doesn't have a fallthru (e.g. when followed by
3844 __builtin_unreachable ()), nothing to do. */
3846 || bb
->aux
== e_fall
->dest
3847 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3850 /* Otherwise we'll have to use the fallthru fixup below. */
3854 /* Otherwise we have some return, switch or computed
3855 jump. In the 99% case, there should not have been a
3857 gcc_assert (returnjump_p (bb_end_insn
) || !e_fall
);
3863 /* No fallthru implies a noreturn function with EH edges, or
3864 something similarly bizarre. In any case, we don't need to
3869 /* If the fallthru block is still next, nothing to do. */
3870 if (bb
->aux
== e_fall
->dest
)
3873 /* A fallthru to exit block. */
3874 if (e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3878 /* We got here if we need to add a new jump insn.
3879 Note force_nonfallthru can delete E_FALL and thus we have to
3880 save E_FALL->src prior to the call to force_nonfallthru. */
3881 nb
= force_nonfallthru_and_redirect (e_fall
, e_fall
->dest
, ret_label
);
3886 /* Don't process this new block. */
3891 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3893 /* Annoying special case - jump around dead jumptables left in the code. */
3894 FOR_EACH_BB_FN (bb
, cfun
)
3896 edge e
= find_fallthru_edge (bb
->succs
);
3898 if (e
&& !can_fallthru (e
->src
, e
->dest
))
3899 force_nonfallthru (e
);
3902 /* Ensure goto_locus from edges has some instructions with that locus
3905 FOR_EACH_BB_FN (bb
, cfun
)
3910 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3911 if (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
3912 && !(e
->flags
& EDGE_ABNORMAL
))
3916 basic_block dest
, nb
;
3919 insn
= BB_END (e
->src
);
3920 end
= PREV_INSN (BB_HEAD (e
->src
));
3922 && (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
3923 insn
= PREV_INSN (insn
);
3925 && INSN_LOCATION (insn
) == e
->goto_locus
)
3927 if (simplejump_p (BB_END (e
->src
))
3928 && !INSN_HAS_LOCATION (BB_END (e
->src
)))
3930 INSN_LOCATION (BB_END (e
->src
)) = e
->goto_locus
;
3934 if (dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3936 /* Non-fallthru edges to the exit block cannot be split. */
3937 if (!(e
->flags
& EDGE_FALLTHRU
))
3942 insn
= BB_HEAD (dest
);
3943 end
= NEXT_INSN (BB_END (dest
));
3944 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
3945 insn
= NEXT_INSN (insn
);
3946 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
3947 && INSN_LOCATION (insn
) == e
->goto_locus
)
3950 nb
= split_edge (e
);
3951 if (!INSN_P (BB_END (nb
)))
3952 BB_END (nb
) = emit_insn_after_noloc (gen_nop (), BB_END (nb
),
3954 INSN_LOCATION (BB_END (nb
)) = e
->goto_locus
;
3956 /* If there are other incoming edges to the destination block
3957 with the same goto locus, redirect them to the new block as
3958 well, this can prevent other such blocks from being created
3959 in subsequent iterations of the loop. */
3960 for (ei2
= ei_start (dest
->preds
); (e2
= ei_safe_edge (ei2
)); )
3961 if (LOCATION_LOCUS (e2
->goto_locus
) != UNKNOWN_LOCATION
3962 && !(e2
->flags
& (EDGE_ABNORMAL
| EDGE_FALLTHRU
))
3963 && e
->goto_locus
== e2
->goto_locus
)
3964 redirect_edge_and_branch (e2
, nb
);
3971 /* Perform sanity checks on the insn chain.
3972 1. Check that next/prev pointers are consistent in both the forward and
3974 2. Count insns in chain, going both directions, and check if equal.
3975 3. Check that get_last_insn () returns the actual end of chain. */
3978 verify_insn_chain (void)
3980 rtx_insn
*x
, *prevx
, *nextx
;
3981 int insn_cnt1
, insn_cnt2
;
3983 for (prevx
= NULL
, insn_cnt1
= 1, x
= get_insns ();
3985 prevx
= x
, insn_cnt1
++, x
= NEXT_INSN (x
))
3986 gcc_assert (PREV_INSN (x
) == prevx
);
3988 gcc_assert (prevx
== get_last_insn ());
3990 for (nextx
= NULL
, insn_cnt2
= 1, x
= get_last_insn ();
3992 nextx
= x
, insn_cnt2
++, x
= PREV_INSN (x
))
3993 gcc_assert (NEXT_INSN (x
) == nextx
);
3995 gcc_assert (insn_cnt1
== insn_cnt2
);
3998 /* If we have assembler epilogues, the block falling through to exit must
3999 be the last one in the reordered chain when we reach final. Ensure
4000 that this condition is met. */
4002 fixup_fallthru_exit_predecessor (void)
4005 basic_block bb
= NULL
;
4007 /* This transformation is not valid before reload, because we might
4008 separate a call from the instruction that copies the return
4010 gcc_assert (reload_completed
);
4012 e
= find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4018 basic_block c
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
4020 /* If the very first block is the one with the fall-through exit
4021 edge, we have to split that block. */
4024 bb
= split_block_after_labels (bb
)->dest
;
4027 BB_FOOTER (bb
) = BB_FOOTER (c
);
4028 BB_FOOTER (c
) = NULL
;
4031 while (c
->aux
!= bb
)
4032 c
= (basic_block
) c
->aux
;
4036 c
= (basic_block
) c
->aux
;
4043 /* In case there are more than one fallthru predecessors of exit, force that
4044 there is only one. */
4047 force_one_exit_fallthru (void)
4049 edge e
, predecessor
= NULL
;
4052 basic_block forwarder
, bb
;
4054 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
4055 if (e
->flags
& EDGE_FALLTHRU
)
4057 if (predecessor
== NULL
)
4069 /* Exit has several fallthru predecessors. Create a forwarder block for
4071 forwarder
= split_edge (predecessor
);
4072 for (ei
= ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4073 (e
= ei_safe_edge (ei
)); )
4075 if (e
->src
== forwarder
4076 || !(e
->flags
& EDGE_FALLTHRU
))
4079 redirect_edge_and_branch_force (e
, forwarder
);
4082 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
4084 FOR_EACH_BB_FN (bb
, cfun
)
4086 if (bb
->aux
== NULL
&& bb
!= forwarder
)
4088 bb
->aux
= forwarder
;
4094 /* Return true in case it is possible to duplicate the basic block BB. */
4097 cfg_layout_can_duplicate_bb_p (const_basic_block bb
)
4099 /* Do not attempt to duplicate tablejumps, as we need to unshare
4100 the dispatch table. This is difficult to do, as the instructions
4101 computing jump destination may be hoisted outside the basic block. */
4102 if (tablejump_p (BB_END (bb
), NULL
, NULL
))
4105 /* Do not duplicate blocks containing insns that can't be copied. */
4106 if (targetm
.cannot_copy_insn_p
)
4108 rtx_insn
*insn
= BB_HEAD (bb
);
4111 if (INSN_P (insn
) && targetm
.cannot_copy_insn_p (insn
))
4113 if (insn
== BB_END (bb
))
4115 insn
= NEXT_INSN (insn
);
4123 duplicate_insn_chain (rtx_insn
*from
, rtx_insn
*to
)
4125 rtx_insn
*insn
, *next
, *copy
;
4128 /* Avoid updating of boundaries of previous basic block. The
4129 note will get removed from insn stream in fixup. */
4130 last
= emit_note (NOTE_INSN_DELETED
);
4132 /* Create copy at the end of INSN chain. The chain will
4133 be reordered later. */
4134 for (insn
= from
; insn
!= NEXT_INSN (to
); insn
= NEXT_INSN (insn
))
4136 switch (GET_CODE (insn
))
4139 /* Don't duplicate label debug insns. */
4140 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn
)) == LABEL_DECL
)
4146 copy
= emit_copy_of_insn_after (insn
, get_last_insn ());
4147 if (JUMP_P (insn
) && JUMP_LABEL (insn
) != NULL_RTX
4148 && ANY_RETURN_P (JUMP_LABEL (insn
)))
4149 JUMP_LABEL (copy
) = JUMP_LABEL (insn
);
4150 maybe_copy_prologue_epilogue_insn (insn
, copy
);
4153 case JUMP_TABLE_DATA
:
4154 /* Avoid copying of dispatch tables. We never duplicate
4155 tablejumps, so this can hit only in case the table got
4156 moved far from original jump.
4157 Avoid copying following barrier as well if any
4158 (and debug insns in between). */
4159 for (next
= NEXT_INSN (insn
);
4160 next
!= NEXT_INSN (to
);
4161 next
= NEXT_INSN (next
))
4162 if (!DEBUG_INSN_P (next
))
4164 if (next
!= NEXT_INSN (to
) && BARRIER_P (next
))
4176 switch (NOTE_KIND (insn
))
4178 /* In case prologue is empty and function contain label
4179 in first BB, we may want to copy the block. */
4180 case NOTE_INSN_PROLOGUE_END
:
4182 case NOTE_INSN_DELETED
:
4183 case NOTE_INSN_DELETED_LABEL
:
4184 case NOTE_INSN_DELETED_DEBUG_LABEL
:
4185 /* No problem to strip these. */
4186 case NOTE_INSN_FUNCTION_BEG
:
4187 /* There is always just single entry to function. */
4188 case NOTE_INSN_BASIC_BLOCK
:
4189 /* We should only switch text sections once. */
4190 case NOTE_INSN_SWITCH_TEXT_SECTIONS
:
4193 case NOTE_INSN_EPILOGUE_BEG
:
4194 case NOTE_INSN_UPDATE_SJLJ_CONTEXT
:
4195 emit_note_copy (as_a
<rtx_note
*> (insn
));
4199 /* All other notes should have already been eliminated. */
4207 insn
= NEXT_INSN (last
);
4212 /* Create a duplicate of the basic block BB. */
4215 cfg_layout_duplicate_bb (basic_block bb
)
4220 insn
= duplicate_insn_chain (BB_HEAD (bb
), BB_END (bb
));
4221 new_bb
= create_basic_block (insn
,
4222 insn
? get_last_insn () : NULL
,
4223 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
);
4225 BB_COPY_PARTITION (new_bb
, bb
);
4228 insn
= BB_HEADER (bb
);
4229 while (NEXT_INSN (insn
))
4230 insn
= NEXT_INSN (insn
);
4231 insn
= duplicate_insn_chain (BB_HEADER (bb
), insn
);
4233 BB_HEADER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4238 insn
= BB_FOOTER (bb
);
4239 while (NEXT_INSN (insn
))
4240 insn
= NEXT_INSN (insn
);
4241 insn
= duplicate_insn_chain (BB_FOOTER (bb
), insn
);
4243 BB_FOOTER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4250 /* Main entry point to this module - initialize the datastructures for
4251 CFG layout changes. It keeps LOOPS up-to-date if not null.
4253 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
4256 cfg_layout_initialize (int flags
)
4261 /* Once bb partitioning is complete, cfg layout mode should not be
4262 re-entered. Entering cfg layout mode may require fixups. As an
4263 example, if edge forwarding performed when optimizing the cfg
4264 layout required moving a block from the hot to the cold
4265 section. This would create an illegal partitioning unless some
4266 manual fixup was performed. */
4267 gcc_assert (!crtl
->bb_reorder_complete
|| !crtl
->has_bb_partition
);
4269 initialize_original_copy_tables ();
4271 cfg_layout_rtl_register_cfg_hooks ();
4273 record_effective_endpoints ();
4275 /* Make sure that the targets of non local gotos are marked. */
4276 for (x
= nonlocal_goto_handler_labels
; x
; x
= x
->next ())
4278 bb
= BLOCK_FOR_INSN (x
->insn ());
4279 bb
->flags
|= BB_NON_LOCAL_GOTO_TARGET
;
4282 cleanup_cfg (CLEANUP_CFGLAYOUT
| flags
);
4285 /* Splits superblocks. */
4287 break_superblocks (void)
4292 auto_sbitmap
superblocks (last_basic_block_for_fn (cfun
));
4293 bitmap_clear (superblocks
);
4295 FOR_EACH_BB_FN (bb
, cfun
)
4296 if (bb
->flags
& BB_SUPERBLOCK
)
4298 bb
->flags
&= ~BB_SUPERBLOCK
;
4299 bitmap_set_bit (superblocks
, bb
->index
);
4305 rebuild_jump_labels (get_insns ());
4306 find_many_sub_basic_blocks (superblocks
);
4310 /* Finalize the changes: reorder insn list according to the sequence specified
4311 by aux pointers, enter compensation code, rebuild scope forest. */
4314 cfg_layout_finalize (void)
4316 checking_verify_flow_info ();
4317 free_dominance_info (CDI_DOMINATORS
);
4318 force_one_exit_fallthru ();
4319 rtl_register_cfg_hooks ();
4320 if (reload_completed
&& !targetm
.have_epilogue ())
4321 fixup_fallthru_exit_predecessor ();
4322 fixup_reorder_chain ();
4324 rebuild_jump_labels (get_insns ());
4325 delete_dead_jumptables ();
4328 verify_insn_chain ();
4329 checking_verify_flow_info ();
4333 /* Same as split_block but update cfg_layout structures. */
4336 cfg_layout_split_block (basic_block bb
, void *insnp
)
4338 rtx insn
= (rtx
) insnp
;
4339 basic_block new_bb
= rtl_split_block (bb
, insn
);
4341 BB_FOOTER (new_bb
) = BB_FOOTER (bb
);
4342 BB_FOOTER (bb
) = NULL
;
4347 /* Redirect Edge to DEST. */
4349 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
4351 basic_block src
= e
->src
;
4354 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4357 if (e
->dest
== dest
)
4360 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4361 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
4363 df_set_bb_dirty (src
);
4367 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4368 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
4371 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
4372 e
->src
->index
, dest
->index
);
4374 df_set_bb_dirty (e
->src
);
4375 redirect_edge_succ (e
, dest
);
4379 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
4380 in the case the basic block appears to be in sequence. Avoid this
4383 if (e
->flags
& EDGE_FALLTHRU
)
4385 /* Redirect any branch edges unified with the fallthru one. */
4386 if (JUMP_P (BB_END (src
))
4387 && label_is_jump_target_p (BB_HEAD (e
->dest
),
4393 fprintf (dump_file
, "Fallthru edge unified with branch "
4394 "%i->%i redirected to %i\n",
4395 e
->src
->index
, e
->dest
->index
, dest
->index
);
4396 e
->flags
&= ~EDGE_FALLTHRU
;
4397 redirected
= redirect_branch_edge (e
, dest
);
4398 gcc_assert (redirected
);
4399 redirected
->flags
|= EDGE_FALLTHRU
;
4400 df_set_bb_dirty (redirected
->src
);
4403 /* In case we are redirecting fallthru edge to the branch edge
4404 of conditional jump, remove it. */
4405 if (EDGE_COUNT (src
->succs
) == 2)
4407 /* Find the edge that is different from E. */
4408 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
4411 && any_condjump_p (BB_END (src
))
4412 && onlyjump_p (BB_END (src
)))
4413 delete_insn (BB_END (src
));
4416 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
4417 e
->src
->index
, e
->dest
->index
, dest
->index
);
4418 ret
= redirect_edge_succ_nodup (e
, dest
);
4421 ret
= redirect_branch_edge (e
, dest
);
4423 /* We don't want simplejumps in the insn stream during cfglayout. */
4424 gcc_assert (!simplejump_p (BB_END (src
)));
4426 df_set_bb_dirty (src
);
4430 /* Simple wrapper as we always can redirect fallthru edges. */
4432 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4434 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
4436 gcc_assert (redirected
);
4440 /* Same as delete_basic_block but update cfg_layout structures. */
4443 cfg_layout_delete_block (basic_block bb
)
4445 rtx_insn
*insn
, *next
, *prev
= PREV_INSN (BB_HEAD (bb
)), *remaints
;
4450 next
= BB_HEAD (bb
);
4452 SET_NEXT_INSN (prev
) = BB_HEADER (bb
);
4454 set_first_insn (BB_HEADER (bb
));
4455 SET_PREV_INSN (BB_HEADER (bb
)) = prev
;
4456 insn
= BB_HEADER (bb
);
4457 while (NEXT_INSN (insn
))
4458 insn
= NEXT_INSN (insn
);
4459 SET_NEXT_INSN (insn
) = next
;
4460 SET_PREV_INSN (next
) = insn
;
4462 next
= NEXT_INSN (BB_END (bb
));
4465 insn
= BB_FOOTER (bb
);
4468 if (BARRIER_P (insn
))
4470 if (PREV_INSN (insn
))
4471 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
4473 BB_FOOTER (bb
) = NEXT_INSN (insn
);
4474 if (NEXT_INSN (insn
))
4475 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
4479 insn
= NEXT_INSN (insn
);
4484 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
4485 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
4486 while (NEXT_INSN (insn
))
4487 insn
= NEXT_INSN (insn
);
4488 SET_NEXT_INSN (insn
) = next
;
4490 SET_PREV_INSN (next
) = insn
;
4492 set_last_insn (insn
);
4495 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4496 to
= &BB_HEADER (bb
->next_bb
);
4498 to
= &cfg_layout_function_footer
;
4500 rtl_delete_block (bb
);
4503 prev
= NEXT_INSN (prev
);
4505 prev
= get_insns ();
4507 next
= PREV_INSN (next
);
4509 next
= get_last_insn ();
4511 if (next
&& NEXT_INSN (next
) != prev
)
4513 remaints
= unlink_insn_chain (prev
, next
);
4515 while (NEXT_INSN (insn
))
4516 insn
= NEXT_INSN (insn
);
4517 SET_NEXT_INSN (insn
) = *to
;
4519 SET_PREV_INSN (*to
) = insn
;
4524 /* Return true when blocks A and B can be safely merged. */
4527 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
4529 /* If we are partitioning hot/cold basic blocks, we don't want to
4530 mess up unconditional or indirect jumps that cross between hot
4533 Basic block partitioning may result in some jumps that appear to
4534 be optimizable (or blocks that appear to be mergeable), but which really
4535 must be left untouched (they are required to make it safely across
4536 partition boundaries). See the comments at the top of
4537 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4539 if (BB_PARTITION (a
) != BB_PARTITION (b
))
4542 /* Protect the loop latches. */
4543 if (current_loops
&& b
->loop_father
->latch
== b
)
4546 /* If we would end up moving B's instructions, make sure it doesn't fall
4547 through into the exit block, since we cannot recover from a fallthrough
4548 edge into the exit block occurring in the middle of a function. */
4549 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4551 edge e
= find_fallthru_edge (b
->succs
);
4552 if (e
&& e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4556 /* There must be exactly one edge in between the blocks. */
4557 return (single_succ_p (a
)
4558 && single_succ (a
) == b
4559 && single_pred_p (b
) == 1
4561 /* Must be simple edge. */
4562 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
4563 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4564 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
4565 /* If the jump insn has side effects, we can't kill the edge.
4566 When not optimizing, try_redirect_by_replacing_jump will
4567 not allow us to redirect an edge by replacing a table jump. */
4568 && (!JUMP_P (BB_END (a
))
4569 || ((!optimize
|| reload_completed
)
4570 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
4573 /* Merge block A and B. The blocks must be mergeable. */
4576 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
4578 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
4581 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
4584 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
4587 /* If there was a CODE_LABEL beginning B, delete it. */
4588 if (LABEL_P (BB_HEAD (b
)))
4590 delete_insn (BB_HEAD (b
));
4593 /* We should have fallthru edge in a, or we can do dummy redirection to get
4595 if (JUMP_P (BB_END (a
)))
4596 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
4597 gcc_assert (!JUMP_P (BB_END (a
)));
4599 /* When not optimizing and the edge is the only place in RTL which holds
4600 some unique locus, emit a nop with that locus in between. */
4602 emit_nop_for_unique_locus_between (a
, b
);
4604 /* Move things from b->footer after a->footer. */
4608 BB_FOOTER (a
) = BB_FOOTER (b
);
4611 rtx_insn
*last
= BB_FOOTER (a
);
4613 while (NEXT_INSN (last
))
4614 last
= NEXT_INSN (last
);
4615 SET_NEXT_INSN (last
) = BB_FOOTER (b
);
4616 SET_PREV_INSN (BB_FOOTER (b
)) = last
;
4618 BB_FOOTER (b
) = NULL
;
4621 /* Move things from b->header before a->footer.
4622 Note that this may include dead tablejump data, but we don't clean
4623 those up until we go out of cfglayout mode. */
4626 if (! BB_FOOTER (a
))
4627 BB_FOOTER (a
) = BB_HEADER (b
);
4630 rtx_insn
*last
= BB_HEADER (b
);
4632 while (NEXT_INSN (last
))
4633 last
= NEXT_INSN (last
);
4634 SET_NEXT_INSN (last
) = BB_FOOTER (a
);
4635 SET_PREV_INSN (BB_FOOTER (a
)) = last
;
4636 BB_FOOTER (a
) = BB_HEADER (b
);
4638 BB_HEADER (b
) = NULL
;
4641 /* In the case basic blocks are not adjacent, move them around. */
4642 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4644 insn
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
4646 emit_insn_after_noloc (insn
, BB_END (a
), a
);
4648 /* Otherwise just re-associate the instructions. */
4652 BB_END (a
) = BB_END (b
);
4655 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4656 We need to explicitly call. */
4657 update_bb_for_insn_chain (insn
, BB_END (b
), a
);
4659 /* Skip possible DELETED_LABEL insn. */
4660 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
4661 insn
= NEXT_INSN (insn
);
4662 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
4663 BB_HEAD (b
) = BB_END (b
) = NULL
;
4666 df_bb_delete (b
->index
);
4668 /* If B was a forwarder block, propagate the locus on the edge. */
4670 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
4671 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
4674 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
4680 cfg_layout_split_edge (edge e
)
4682 basic_block new_bb
=
4683 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4684 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
4687 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4688 BB_COPY_PARTITION (new_bb
, e
->src
);
4690 BB_COPY_PARTITION (new_bb
, e
->dest
);
4691 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
4692 redirect_edge_and_branch_force (e
, new_bb
);
4697 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4700 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
4704 /* Return true if BB contains only labels or non-executable
4708 rtl_block_empty_p (basic_block bb
)
4712 if (bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4713 || bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4716 FOR_BB_INSNS (bb
, insn
)
4717 if (NONDEBUG_INSN_P (insn
) && !any_uncondjump_p (insn
))
4723 /* Split a basic block if it ends with a conditional branch and if
4724 the other part of the block is not empty. */
4727 rtl_split_block_before_cond_jump (basic_block bb
)
4730 rtx_insn
*split_point
= NULL
;
4731 rtx_insn
*last
= NULL
;
4732 bool found_code
= false;
4734 FOR_BB_INSNS (bb
, insn
)
4736 if (any_condjump_p (insn
))
4738 else if (NONDEBUG_INSN_P (insn
))
4743 /* Did not find everything. */
4744 if (found_code
&& split_point
)
4745 return split_block (bb
, split_point
)->dest
;
4750 /* Return 1 if BB ends with a call, possibly followed by some
4751 instructions that must stay with the call, 0 otherwise. */
4754 rtl_block_ends_with_call_p (basic_block bb
)
4756 rtx_insn
*insn
= BB_END (bb
);
4758 while (!CALL_P (insn
)
4759 && insn
!= BB_HEAD (bb
)
4760 && (keep_with_call_p (insn
)
4762 || DEBUG_INSN_P (insn
)))
4763 insn
= PREV_INSN (insn
);
4764 return (CALL_P (insn
));
4767 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4770 rtl_block_ends_with_condjump_p (const_basic_block bb
)
4772 return any_condjump_p (BB_END (bb
));
4775 /* Return true if we need to add fake edge to exit.
4776 Helper function for rtl_flow_call_edges_add. */
4779 need_fake_edge_p (const rtx_insn
*insn
)
4785 && !SIBLING_CALL_P (insn
)
4786 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
4787 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
4790 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
4791 && MEM_VOLATILE_P (PATTERN (insn
)))
4792 || (GET_CODE (PATTERN (insn
)) == PARALLEL
4793 && asm_noperands (insn
) != -1
4794 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
4795 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
4798 /* Add fake edges to the function exit for any non constant and non noreturn
4799 calls, volatile inline assembly in the bitmap of blocks specified by
4800 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4803 The goal is to expose cases in which entering a basic block does not imply
4804 that all subsequent instructions must be executed. */
4807 rtl_flow_call_edges_add (sbitmap blocks
)
4810 int blocks_split
= 0;
4811 int last_bb
= last_basic_block_for_fn (cfun
);
4812 bool check_last_block
= false;
4814 if (n_basic_blocks_for_fn (cfun
) == NUM_FIXED_BLOCKS
)
4818 check_last_block
= true;
4820 check_last_block
= bitmap_bit_p (blocks
,
4821 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
->index
);
4823 /* In the last basic block, before epilogue generation, there will be
4824 a fallthru edge to EXIT. Special care is required if the last insn
4825 of the last basic block is a call because make_edge folds duplicate
4826 edges, which would result in the fallthru edge also being marked
4827 fake, which would result in the fallthru edge being removed by
4828 remove_fake_edges, which would result in an invalid CFG.
4830 Moreover, we can't elide the outgoing fake edge, since the block
4831 profiler needs to take this into account in order to solve the minimal
4832 spanning tree in the case that the call doesn't return.
4834 Handle this by adding a dummy instruction in a new last basic block. */
4835 if (check_last_block
)
4837 basic_block bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
;
4838 rtx_insn
*insn
= BB_END (bb
);
4840 /* Back up past insns that must be kept in the same block as a call. */
4841 while (insn
!= BB_HEAD (bb
)
4842 && keep_with_call_p (insn
))
4843 insn
= PREV_INSN (insn
);
4845 if (need_fake_edge_p (insn
))
4849 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4852 insert_insn_on_edge (gen_use (const0_rtx
), e
);
4853 commit_edge_insertions ();
4858 /* Now add fake edges to the function exit for any non constant
4859 calls since there is no way that we can determine if they will
4862 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
4864 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
4866 rtx_insn
*prev_insn
;
4871 if (blocks
&& !bitmap_bit_p (blocks
, i
))
4874 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
4876 prev_insn
= PREV_INSN (insn
);
4877 if (need_fake_edge_p (insn
))
4880 rtx_insn
*split_at_insn
= insn
;
4882 /* Don't split the block between a call and an insn that should
4883 remain in the same block as the call. */
4885 while (split_at_insn
!= BB_END (bb
)
4886 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
4887 split_at_insn
= NEXT_INSN (split_at_insn
);
4889 /* The handling above of the final block before the epilogue
4890 should be enough to verify that there is no edge to the exit
4891 block in CFG already. Calling make_edge in such case would
4892 cause us to mark that edge as fake and remove it later. */
4894 if (flag_checking
&& split_at_insn
== BB_END (bb
))
4896 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4897 gcc_assert (e
== NULL
);
4900 /* Note that the following may create a new basic block
4901 and renumber the existing basic blocks. */
4902 if (split_at_insn
!= BB_END (bb
))
4904 e
= split_block (bb
, split_at_insn
);
4909 edge ne
= make_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), EDGE_FAKE
);
4910 ne
->probability
= profile_probability::guessed_never ();
4913 if (insn
== BB_HEAD (bb
))
4919 verify_flow_info ();
4921 return blocks_split
;
4924 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4925 the conditional branch target, SECOND_HEAD should be the fall-thru
4926 there is no need to handle this here the loop versioning code handles
4927 this. the reason for SECON_HEAD is that it is needed for condition
4928 in trees, and this should be of the same type since it is a hook. */
4930 rtl_lv_add_condition_to_bb (basic_block first_head
,
4931 basic_block second_head ATTRIBUTE_UNUSED
,
4932 basic_block cond_bb
, void *comp_rtx
)
4934 rtx_code_label
*label
;
4935 rtx_insn
*seq
, *jump
;
4936 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
4937 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
4938 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
4942 label
= block_label (first_head
);
4943 mode
= GET_MODE (op0
);
4944 if (mode
== VOIDmode
)
4945 mode
= GET_MODE (op1
);
4948 op0
= force_operand (op0
, NULL_RTX
);
4949 op1
= force_operand (op1
, NULL_RTX
);
4950 do_compare_rtx_and_jump (op0
, op1
, comp
, 0, mode
, NULL_RTX
, NULL
, label
,
4951 profile_probability::uninitialized ());
4952 jump
= get_last_insn ();
4953 JUMP_LABEL (jump
) = label
;
4954 LABEL_NUSES (label
)++;
4958 /* Add the new cond, in the new head. */
4959 emit_insn_after (seq
, BB_END (cond_bb
));
4963 /* Given a block B with unconditional branch at its end, get the
4964 store the return the branch edge and the fall-thru edge in
4965 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4967 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
4968 edge
*fallthru_edge
)
4970 edge e
= EDGE_SUCC (b
, 0);
4972 if (e
->flags
& EDGE_FALLTHRU
)
4975 *branch_edge
= EDGE_SUCC (b
, 1);
4980 *fallthru_edge
= EDGE_SUCC (b
, 1);
4985 init_rtl_bb_info (basic_block bb
)
4987 gcc_assert (!bb
->il
.x
.rtl
);
4988 bb
->il
.x
.head_
= NULL
;
4989 bb
->il
.x
.rtl
= ggc_cleared_alloc
<rtl_bb_info
> ();
4992 /* Returns true if it is possible to remove edge E by redirecting
4993 it to the destination of the other edge from E->src. */
4996 rtl_can_remove_branch_p (const_edge e
)
4998 const_basic_block src
= e
->src
;
4999 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
5000 const rtx_insn
*insn
= BB_END (src
);
5003 /* The conditions are taken from try_redirect_by_replacing_jump. */
5004 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
5007 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
5010 if (BB_PARTITION (src
) != BB_PARTITION (target
))
5013 if (!onlyjump_p (insn
)
5014 || tablejump_p (insn
, NULL
, NULL
))
5017 set
= single_set (insn
);
5018 if (!set
|| side_effects_p (set
))
5025 rtl_duplicate_bb (basic_block bb
)
5027 bb
= cfg_layout_duplicate_bb (bb
);
5032 /* Do book-keeping of basic block BB for the profile consistency checker.
5033 If AFTER_PASS is 0, do pre-pass accounting, or if AFTER_PASS is 1
5034 then do post-pass accounting. Store the counting in RECORD. */
5036 rtl_account_profile_record (basic_block bb
, int after_pass
,
5037 struct profile_record
*record
)
5040 FOR_BB_INSNS (bb
, insn
)
5043 record
->size
[after_pass
] += insn_cost (insn
, false);
5044 if (bb
->count
.initialized_p ())
5045 record
->time
[after_pass
]
5046 += insn_cost (insn
, true) * bb
->count
.to_gcov_type ();
5047 else if (profile_status_for_fn (cfun
) == PROFILE_GUESSED
)
5048 record
->time
[after_pass
]
5049 += insn_cost (insn
, true) * bb
->count
.to_frequency (cfun
);
5053 /* Implementation of CFG manipulation for linearized RTL. */
5054 struct cfg_hooks rtl_cfg_hooks
= {
5056 rtl_verify_flow_info
,
5058 rtl_dump_bb_for_graph
,
5059 rtl_create_basic_block
,
5060 rtl_redirect_edge_and_branch
,
5061 rtl_redirect_edge_and_branch_force
,
5062 rtl_can_remove_branch_p
,
5065 rtl_move_block_after
,
5066 rtl_can_merge_blocks
, /* can_merge_blocks_p */
5070 cfg_layout_can_duplicate_bb_p
,
5073 rtl_make_forwarder_block
,
5074 rtl_tidy_fallthru_edge
,
5075 rtl_force_nonfallthru
,
5076 rtl_block_ends_with_call_p
,
5077 rtl_block_ends_with_condjump_p
,
5078 rtl_flow_call_edges_add
,
5079 NULL
, /* execute_on_growing_pred */
5080 NULL
, /* execute_on_shrinking_pred */
5081 NULL
, /* duplicate loop for trees */
5082 NULL
, /* lv_add_condition_to_bb */
5083 NULL
, /* lv_adjust_loop_header_phi*/
5084 NULL
, /* extract_cond_bb_edges */
5085 NULL
, /* flush_pending_stmts */
5086 rtl_block_empty_p
, /* block_empty_p */
5087 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5088 rtl_account_profile_record
,
5091 /* Implementation of CFG manipulation for cfg layout RTL, where
5092 basic block connected via fallthru edges does not have to be adjacent.
5093 This representation will hopefully become the default one in future
5094 version of the compiler. */
5096 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
5098 rtl_verify_flow_info_1
,
5100 rtl_dump_bb_for_graph
,
5101 cfg_layout_create_basic_block
,
5102 cfg_layout_redirect_edge_and_branch
,
5103 cfg_layout_redirect_edge_and_branch_force
,
5104 rtl_can_remove_branch_p
,
5105 cfg_layout_delete_block
,
5106 cfg_layout_split_block
,
5107 rtl_move_block_after
,
5108 cfg_layout_can_merge_blocks_p
,
5109 cfg_layout_merge_blocks
,
5112 cfg_layout_can_duplicate_bb_p
,
5113 cfg_layout_duplicate_bb
,
5114 cfg_layout_split_edge
,
5115 rtl_make_forwarder_block
,
5116 NULL
, /* tidy_fallthru_edge */
5117 rtl_force_nonfallthru
,
5118 rtl_block_ends_with_call_p
,
5119 rtl_block_ends_with_condjump_p
,
5120 rtl_flow_call_edges_add
,
5121 NULL
, /* execute_on_growing_pred */
5122 NULL
, /* execute_on_shrinking_pred */
5123 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5124 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5125 NULL
, /* lv_adjust_loop_header_phi*/
5126 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
5127 NULL
, /* flush_pending_stmts */
5128 rtl_block_empty_p
, /* block_empty_p */
5129 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5130 rtl_account_profile_record
,
5133 #include "gt-cfgrtl.h"