1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987-2019 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 /* Disable warnings about missing quoting in GCC diagnostics. */
67 # pragma GCC diagnostic push
68 # pragma GCC diagnostic ignored "-Wformat-diag"
71 /* Holds the interesting leading and trailing notes for the function.
72 Only applicable if the CFG is in cfglayout mode. */
73 static GTY(()) rtx_insn
*cfg_layout_function_footer
;
74 static GTY(()) rtx_insn
*cfg_layout_function_header
;
76 static rtx_insn
*skip_insns_after_block (basic_block
);
77 static void record_effective_endpoints (void);
78 static void fixup_reorder_chain (void);
80 void verify_insn_chain (void);
81 static void fixup_fallthru_exit_predecessor (void);
82 static int can_delete_note_p (const rtx_note
*);
83 static int can_delete_label_p (const rtx_code_label
*);
84 static basic_block
rtl_split_edge (edge
);
85 static bool rtl_move_block_after (basic_block
, basic_block
);
86 static int rtl_verify_flow_info (void);
87 static basic_block
cfg_layout_split_block (basic_block
, void *);
88 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
89 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
90 static void cfg_layout_delete_block (basic_block
);
91 static void rtl_delete_block (basic_block
);
92 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
93 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
94 static basic_block
rtl_split_block (basic_block
, void *);
95 static void rtl_dump_bb (FILE *, basic_block
, int, dump_flags_t
);
96 static int rtl_verify_flow_info_1 (void);
97 static void rtl_make_forwarder_block (edge
);
99 /* Return true if NOTE is not one of the ones that must be kept paired,
100 so that we may simply delete it. */
103 can_delete_note_p (const rtx_note
*note
)
105 switch (NOTE_KIND (note
))
107 case NOTE_INSN_DELETED
:
108 case NOTE_INSN_BASIC_BLOCK
:
109 case NOTE_INSN_EPILOGUE_BEG
:
117 /* True if a given label can be deleted. */
120 can_delete_label_p (const rtx_code_label
*label
)
122 return (!LABEL_PRESERVE_P (label
)
123 /* User declared labels must be preserved. */
124 && LABEL_NAME (label
) == 0
125 && !vec_safe_contains
<rtx_insn
*> (forced_labels
,
126 const_cast<rtx_code_label
*> (label
)));
129 /* Delete INSN by patching it out. */
132 delete_insn (rtx_insn
*insn
)
135 bool really_delete
= true;
139 /* Some labels can't be directly removed from the INSN chain, as they
140 might be references via variables, constant pool etc.
141 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
142 if (! can_delete_label_p (as_a
<rtx_code_label
*> (insn
)))
144 const char *name
= LABEL_NAME (insn
);
145 basic_block bb
= BLOCK_FOR_INSN (insn
);
146 rtx_insn
*bb_note
= NEXT_INSN (insn
);
148 really_delete
= false;
149 PUT_CODE (insn
, NOTE
);
150 NOTE_KIND (insn
) = NOTE_INSN_DELETED_LABEL
;
151 NOTE_DELETED_LABEL_NAME (insn
) = name
;
153 /* If the note following the label starts a basic block, and the
154 label is a member of the same basic block, interchange the two. */
155 if (bb_note
!= NULL_RTX
156 && NOTE_INSN_BASIC_BLOCK_P (bb_note
)
158 && bb
== BLOCK_FOR_INSN (bb_note
))
160 reorder_insns_nobb (insn
, insn
, bb_note
);
161 BB_HEAD (bb
) = bb_note
;
162 if (BB_END (bb
) == bb_note
)
167 remove_node_from_insn_list (insn
, &nonlocal_goto_handler_labels
);
172 /* If this insn has already been deleted, something is very wrong. */
173 gcc_assert (!insn
->deleted ());
175 df_insn_delete (insn
);
177 insn
->set_deleted ();
180 /* If deleting a jump, decrement the use count of the label. Deleting
181 the label itself should happen in the normal course of block merging. */
184 if (JUMP_LABEL (insn
)
185 && LABEL_P (JUMP_LABEL (insn
)))
186 LABEL_NUSES (JUMP_LABEL (insn
))--;
188 /* If there are more targets, remove them too. */
190 = find_reg_note (insn
, REG_LABEL_TARGET
, NULL_RTX
)) != NULL_RTX
191 && LABEL_P (XEXP (note
, 0)))
193 LABEL_NUSES (XEXP (note
, 0))--;
194 remove_note (insn
, note
);
198 /* Also if deleting any insn that references a label as an operand. */
199 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, NULL_RTX
)) != NULL_RTX
200 && LABEL_P (XEXP (note
, 0)))
202 LABEL_NUSES (XEXP (note
, 0))--;
203 remove_note (insn
, note
);
206 if (rtx_jump_table_data
*table
= dyn_cast
<rtx_jump_table_data
*> (insn
))
208 rtvec vec
= table
->get_labels ();
209 int len
= GET_NUM_ELEM (vec
);
212 for (i
= 0; i
< len
; i
++)
214 rtx label
= XEXP (RTVEC_ELT (vec
, i
), 0);
216 /* When deleting code in bulk (e.g. removing many unreachable
217 blocks) we can delete a label that's a target of the vector
218 before deleting the vector itself. */
220 LABEL_NUSES (label
)--;
225 /* Like delete_insn but also purge dead edges from BB.
226 Return true if any edges are eliminated. */
229 delete_insn_and_edges (rtx_insn
*insn
)
234 && BLOCK_FOR_INSN (insn
)
235 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
239 return purge_dead_edges (BLOCK_FOR_INSN (insn
));
243 /* Unlink a chain of insns between START and FINISH, leaving notes
244 that must be paired. If CLEAR_BB is true, we set bb field for
245 insns that cannot be removed to NULL. */
248 delete_insn_chain (rtx start
, rtx_insn
*finish
, bool clear_bb
)
250 /* Unchain the insns one by one. It would be quicker to delete all of these
251 with a single unchaining, rather than one at a time, but we need to keep
253 rtx_insn
*current
= finish
;
256 rtx_insn
*prev
= PREV_INSN (current
);
257 if (NOTE_P (current
) && !can_delete_note_p (as_a
<rtx_note
*> (current
)))
260 delete_insn (current
);
262 if (clear_bb
&& !current
->deleted ())
263 set_block_for_insn (current
, NULL
);
265 if (current
== start
)
271 /* Create a new basic block consisting of the instructions between HEAD and END
272 inclusive. This function is designed to allow fast BB construction - reuses
273 the note and basic block struct in BB_NOTE, if any and do not grow
274 BASIC_BLOCK chain and should be used directly only by CFG construction code.
275 END can be NULL in to create new empty basic block before HEAD. Both END
276 and HEAD can be NULL to create basic block at the end of INSN chain.
277 AFTER is the basic block we should be put after. */
280 create_basic_block_structure (rtx_insn
*head
, rtx_insn
*end
, rtx_note
*bb_note
,
286 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
289 /* If we found an existing note, thread it back onto the chain. */
297 after
= PREV_INSN (head
);
301 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
302 reorder_insns_nobb (bb_note
, bb_note
, after
);
306 /* Otherwise we must create a note and a basic block structure. */
310 init_rtl_bb_info (bb
);
313 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
314 else if (LABEL_P (head
) && end
)
316 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
322 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
328 NOTE_BASIC_BLOCK (bb_note
) = bb
;
331 /* Always include the bb note in the block. */
332 if (NEXT_INSN (end
) == bb_note
)
337 bb
->index
= last_basic_block_for_fn (cfun
)++;
338 bb
->flags
= BB_NEW
| BB_RTL
;
339 link_block (bb
, after
);
340 SET_BASIC_BLOCK_FOR_FN (cfun
, bb
->index
, bb
);
341 df_bb_refs_record (bb
->index
, false);
342 update_bb_for_insn (bb
);
343 BB_SET_PARTITION (bb
, BB_UNPARTITIONED
);
345 /* Tag the block so that we know it has been used when considering
346 other basic block notes. */
352 /* Create new basic block consisting of instructions in between HEAD and END
353 and place it to the BB chain after block AFTER. END can be NULL to
354 create a new empty basic block before HEAD. Both END and HEAD can be
355 NULL to create basic block at the end of INSN chain. */
358 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
360 rtx_insn
*head
= (rtx_insn
*) headp
;
361 rtx_insn
*end
= (rtx_insn
*) endp
;
364 /* Grow the basic block array if needed. */
365 if ((size_t) last_basic_block_for_fn (cfun
)
366 >= basic_block_info_for_fn (cfun
)->length ())
369 (last_basic_block_for_fn (cfun
)
370 + (last_basic_block_for_fn (cfun
) + 3) / 4);
371 vec_safe_grow_cleared (basic_block_info_for_fn (cfun
), new_size
);
374 n_basic_blocks_for_fn (cfun
)++;
376 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
382 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
384 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
389 /* Delete the insns in a (non-live) block. We physically delete every
390 non-deleted-note insn, and update the flow graph appropriately.
392 Return nonzero if we deleted an exception handler. */
394 /* ??? Preserving all such notes strikes me as wrong. It would be nice
395 to post-process the stream to remove empty blocks, loops, ranges, etc. */
398 rtl_delete_block (basic_block b
)
400 rtx_insn
*insn
, *end
;
402 /* If the head of this block is a CODE_LABEL, then it might be the
403 label for an exception handler which can't be reached. We need
404 to remove the label from the exception_handler_label list. */
407 end
= get_last_bb_insn (b
);
409 /* Selectively delete the entire chain. */
411 delete_insn_chain (insn
, end
, true);
415 fprintf (dump_file
, "deleting block %d\n", b
->index
);
416 df_bb_delete (b
->index
);
419 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
422 compute_bb_for_insn (void)
426 FOR_EACH_BB_FN (bb
, cfun
)
428 rtx_insn
*end
= BB_END (bb
);
431 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
433 BLOCK_FOR_INSN (insn
) = bb
;
440 /* Release the basic_block_for_insn array. */
443 free_bb_for_insn (void)
446 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
447 if (!BARRIER_P (insn
))
448 BLOCK_FOR_INSN (insn
) = NULL
;
454 const pass_data pass_data_free_cfg
=
457 "*free_cfg", /* name */
458 OPTGROUP_NONE
, /* optinfo_flags */
460 0, /* properties_required */
461 0, /* properties_provided */
462 PROP_cfg
, /* properties_destroyed */
463 0, /* todo_flags_start */
464 0, /* todo_flags_finish */
467 class pass_free_cfg
: public rtl_opt_pass
470 pass_free_cfg (gcc::context
*ctxt
)
471 : rtl_opt_pass (pass_data_free_cfg
, ctxt
)
474 /* opt_pass methods: */
475 virtual unsigned int execute (function
*);
477 }; // class pass_free_cfg
480 pass_free_cfg::execute (function
*)
482 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
483 valid at that point so it would be too late to call df_analyze. */
484 if (DELAY_SLOTS
&& optimize
> 0 && flag_delayed_branch
)
486 df_note_add_problem ();
490 if (crtl
->has_bb_partition
)
491 insert_section_boundary_note ();
500 make_pass_free_cfg (gcc::context
*ctxt
)
502 return new pass_free_cfg (ctxt
);
505 /* Return RTX to emit after when we want to emit code on the entry of function. */
507 entry_of_function (void)
509 return (n_basic_blocks_for_fn (cfun
) > NUM_FIXED_BLOCKS
?
510 BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
) : get_insns ());
513 /* Emit INSN at the entry point of the function, ensuring that it is only
514 executed once per function. */
516 emit_insn_at_entry (rtx insn
)
518 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
519 edge e
= ei_safe_edge (ei
);
520 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
522 insert_insn_on_edge (insn
, e
);
523 commit_edge_insertions ();
526 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
527 (or BARRIER if found) and notify df of the bb change.
528 The insn chain range is inclusive
529 (i.e. both BEGIN and END will be updated. */
532 update_bb_for_insn_chain (rtx_insn
*begin
, rtx_insn
*end
, basic_block bb
)
536 end
= NEXT_INSN (end
);
537 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
538 if (!BARRIER_P (insn
))
539 df_insn_change_bb (insn
, bb
);
542 /* Update BLOCK_FOR_INSN of insns in BB to BB,
543 and notify df of the change. */
546 update_bb_for_insn (basic_block bb
)
548 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
552 /* Like active_insn_p, except keep the return value use or clobber around
553 even after reload. */
556 flow_active_insn_p (const rtx_insn
*insn
)
558 if (active_insn_p (insn
))
561 /* A clobber of the function return value exists for buggy
562 programs that fail to return a value. Its effect is to
563 keep the return value from being live across the entire
564 function. If we allow it to be skipped, we introduce the
565 possibility for register lifetime confusion.
566 Similarly, keep a USE of the function return value, otherwise
567 the USE is dropped and we could fail to thread jump if USE
568 appears on some paths and not on others, see PR90257. */
569 if ((GET_CODE (PATTERN (insn
)) == CLOBBER
570 || GET_CODE (PATTERN (insn
)) == USE
)
571 && REG_P (XEXP (PATTERN (insn
), 0))
572 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn
), 0)))
578 /* Return true if the block has no effect and only forwards control flow to
579 its single destination. */
582 contains_no_active_insn_p (const_basic_block bb
)
586 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
587 || bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
588 || !single_succ_p (bb
)
589 || (single_succ_edge (bb
)->flags
& EDGE_FAKE
) != 0)
592 for (insn
= BB_HEAD (bb
); insn
!= BB_END (bb
); insn
= NEXT_INSN (insn
))
593 if (INSN_P (insn
) && flow_active_insn_p (insn
))
596 return (!INSN_P (insn
)
597 || (JUMP_P (insn
) && simplejump_p (insn
))
598 || !flow_active_insn_p (insn
));
601 /* Likewise, but protect loop latches, headers and preheaders. */
602 /* FIXME: Make this a cfg hook. */
605 forwarder_block_p (const_basic_block bb
)
607 if (!contains_no_active_insn_p (bb
))
610 /* Protect loop latches, headers and preheaders. */
614 if (bb
->loop_father
->header
== bb
)
616 dest
= EDGE_SUCC (bb
, 0)->dest
;
617 if (dest
->loop_father
->header
== dest
)
624 /* Return nonzero if we can reach target from src by falling through. */
625 /* FIXME: Make this a cfg hook, the result is only valid in cfgrtl mode. */
628 can_fallthru (basic_block src
, basic_block target
)
630 rtx_insn
*insn
= BB_END (src
);
635 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
637 if (src
->next_bb
!= target
)
640 /* ??? Later we may add code to move jump tables offline. */
641 if (tablejump_p (insn
, NULL
, NULL
))
644 FOR_EACH_EDGE (e
, ei
, src
->succs
)
645 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
646 && e
->flags
& EDGE_FALLTHRU
)
649 insn2
= BB_HEAD (target
);
650 if (!active_insn_p (insn2
))
651 insn2
= next_active_insn (insn2
);
653 return next_active_insn (insn
) == insn2
;
656 /* Return nonzero if we could reach target from src by falling through,
657 if the target was made adjacent. If we already have a fall-through
658 edge to the exit block, we can't do that. */
660 could_fall_through (basic_block src
, basic_block target
)
665 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
667 FOR_EACH_EDGE (e
, ei
, src
->succs
)
668 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
669 && e
->flags
& EDGE_FALLTHRU
)
674 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
676 bb_note (basic_block bb
)
682 note
= NEXT_INSN (note
);
684 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note
));
685 return as_a
<rtx_note
*> (note
);
688 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
689 note associated with the BLOCK. */
692 first_insn_after_basic_block_note (basic_block block
)
696 /* Get the first instruction in the block. */
697 insn
= BB_HEAD (block
);
699 if (insn
== NULL_RTX
)
702 insn
= NEXT_INSN (insn
);
703 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
705 return NEXT_INSN (insn
);
708 /* Creates a new basic block just after basic block BB by splitting
709 everything after specified instruction INSNP. */
712 rtl_split_block (basic_block bb
, void *insnp
)
715 rtx_insn
*insn
= (rtx_insn
*) insnp
;
721 insn
= first_insn_after_basic_block_note (bb
);
725 rtx_insn
*next
= insn
;
727 insn
= PREV_INSN (insn
);
729 /* If the block contains only debug insns, insn would have
730 been NULL in a non-debug compilation, and then we'd end
731 up emitting a DELETED note. For -fcompare-debug
732 stability, emit the note too. */
733 if (insn
!= BB_END (bb
)
734 && DEBUG_INSN_P (next
)
735 && DEBUG_INSN_P (BB_END (bb
)))
737 while (next
!= BB_END (bb
) && DEBUG_INSN_P (next
))
738 next
= NEXT_INSN (next
);
740 if (next
== BB_END (bb
))
741 emit_note_after (NOTE_INSN_DELETED
, next
);
745 insn
= get_last_insn ();
748 /* We probably should check type of the insn so that we do not create
749 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
751 if (insn
== BB_END (bb
))
752 emit_note_after (NOTE_INSN_DELETED
, insn
);
754 /* Create the new basic block. */
755 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
756 BB_COPY_PARTITION (new_bb
, bb
);
759 /* Redirect the outgoing edges. */
760 new_bb
->succs
= bb
->succs
;
762 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
765 /* The new block starts off being dirty. */
766 df_set_bb_dirty (bb
);
770 /* Return true if the single edge between blocks A and B is the only place
771 in RTL which holds some unique locus. */
774 unique_locus_on_edge_between_p (basic_block a
, basic_block b
)
776 const location_t goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
777 rtx_insn
*insn
, *end
;
779 if (LOCATION_LOCUS (goto_locus
) == UNKNOWN_LOCATION
)
782 /* First scan block A backward. */
784 end
= PREV_INSN (BB_HEAD (a
));
785 while (insn
!= end
&& (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
786 insn
= PREV_INSN (insn
);
788 if (insn
!= end
&& INSN_LOCATION (insn
) == goto_locus
)
791 /* Then scan block B forward. */
795 end
= NEXT_INSN (BB_END (b
));
796 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
797 insn
= NEXT_INSN (insn
);
799 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
800 && INSN_LOCATION (insn
) == goto_locus
)
807 /* If the single edge between blocks A and B is the only place in RTL which
808 holds some unique locus, emit a nop with that locus between the blocks. */
811 emit_nop_for_unique_locus_between (basic_block a
, basic_block b
)
813 if (!unique_locus_on_edge_between_p (a
, b
))
816 BB_END (a
) = emit_insn_after_noloc (gen_nop (), BB_END (a
), a
);
817 INSN_LOCATION (BB_END (a
)) = EDGE_SUCC (a
, 0)->goto_locus
;
820 /* Blocks A and B are to be merged into a single block A. The insns
821 are already contiguous. */
824 rtl_merge_blocks (basic_block a
, basic_block b
)
826 /* If B is a forwarder block whose outgoing edge has no location, we'll
827 propagate the locus of the edge between A and B onto it. */
828 const bool forward_edge_locus
829 = (b
->flags
& BB_FORWARDER_BLOCK
) != 0
830 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
;
831 rtx_insn
*b_head
= BB_HEAD (b
), *b_end
= BB_END (b
), *a_end
= BB_END (a
);
832 rtx_insn
*del_first
= NULL
, *del_last
= NULL
;
833 rtx_insn
*b_debug_start
= b_end
, *b_debug_end
= b_end
;
837 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
840 while (DEBUG_INSN_P (b_end
))
841 b_end
= PREV_INSN (b_debug_start
= b_end
);
843 /* If there was a CODE_LABEL beginning B, delete it. */
844 if (LABEL_P (b_head
))
846 /* Detect basic blocks with nothing but a label. This can happen
847 in particular at the end of a function. */
851 del_first
= del_last
= b_head
;
852 b_head
= NEXT_INSN (b_head
);
855 /* Delete the basic block note and handle blocks containing just that
857 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
865 b_head
= NEXT_INSN (b_head
);
868 /* If there was a jump out of A, delete it. */
873 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
875 || NOTE_INSN_BASIC_BLOCK_P (prev
)
876 || prev
== BB_HEAD (a
))
881 /* If this was a conditional jump, we need to also delete
882 the insn that set cc0. */
883 if (HAVE_cc0
&& only_sets_cc0_p (prev
))
885 rtx_insn
*tmp
= prev
;
887 prev
= prev_nonnote_insn (prev
);
893 a_end
= PREV_INSN (del_first
);
895 else if (BARRIER_P (NEXT_INSN (a_end
)))
896 del_first
= NEXT_INSN (a_end
);
898 /* Delete everything marked above as well as crap that might be
899 hanging out between the two blocks. */
901 BB_HEAD (b
) = b_empty
? NULL
: b_head
;
902 delete_insn_chain (del_first
, del_last
, true);
904 /* If not optimizing, preserve the locus of the single edge between
905 blocks A and B if necessary by emitting a nop. */
907 && !forward_edge_locus
908 && !DECL_IGNORED_P (current_function_decl
))
910 emit_nop_for_unique_locus_between (a
, b
);
914 /* Reassociate the insns of B with A. */
917 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
919 BB_END (a
) = b_debug_end
;
922 else if (b_end
!= b_debug_end
)
924 /* Move any deleted labels and other notes between the end of A
925 and the debug insns that make up B after the debug insns,
926 bringing the debug insns into A while keeping the notes after
928 if (NEXT_INSN (a_end
) != b_debug_start
)
929 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
931 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
932 BB_END (a
) = b_debug_end
;
935 df_bb_delete (b
->index
);
937 if (forward_edge_locus
)
938 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
941 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
945 /* Return true when block A and B can be merged. */
948 rtl_can_merge_blocks (basic_block a
, basic_block b
)
950 /* If we are partitioning hot/cold basic blocks, we don't want to
951 mess up unconditional or indirect jumps that cross between hot
954 Basic block partitioning may result in some jumps that appear to
955 be optimizable (or blocks that appear to be mergeable), but which really
956 must be left untouched (they are required to make it safely across
957 partition boundaries). See the comments at the top of
958 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
960 if (BB_PARTITION (a
) != BB_PARTITION (b
))
963 /* Protect the loop latches. */
964 if (current_loops
&& b
->loop_father
->latch
== b
)
967 /* There must be exactly one edge in between the blocks. */
968 return (single_succ_p (a
)
969 && single_succ (a
) == b
972 /* Must be simple edge. */
973 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
975 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
976 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
977 /* If the jump insn has side effects,
978 we can't kill the edge. */
979 && (!JUMP_P (BB_END (a
))
981 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
984 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
988 block_label (basic_block block
)
990 if (block
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
993 if (!LABEL_P (BB_HEAD (block
)))
995 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
998 return as_a
<rtx_code_label
*> (BB_HEAD (block
));
1001 /* Remove all barriers from BB_FOOTER of a BB. */
1004 remove_barriers_from_footer (basic_block bb
)
1006 rtx_insn
*insn
= BB_FOOTER (bb
);
1008 /* Remove barriers but keep jumptables. */
1011 if (BARRIER_P (insn
))
1013 if (PREV_INSN (insn
))
1014 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
1016 BB_FOOTER (bb
) = NEXT_INSN (insn
);
1017 if (NEXT_INSN (insn
))
1018 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
1022 insn
= NEXT_INSN (insn
);
1026 /* Attempt to perform edge redirection by replacing possibly complex jump
1027 instruction by unconditional jump or removing jump completely. This can
1028 apply only if all edges now point to the same block. The parameters and
1029 return values are equivalent to redirect_edge_and_branch. */
1032 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
1034 basic_block src
= e
->src
;
1035 rtx_insn
*insn
= BB_END (src
), *kill_from
;
1039 /* If we are partitioning hot/cold basic blocks, we don't want to
1040 mess up unconditional or indirect jumps that cross between hot
1043 Basic block partitioning may result in some jumps that appear to
1044 be optimizable (or blocks that appear to be mergeable), but which really
1045 must be left untouched (they are required to make it safely across
1046 partition boundaries). See the comments at the top of
1047 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
1049 if (BB_PARTITION (src
) != BB_PARTITION (target
))
1052 /* We can replace or remove a complex jump only when we have exactly
1053 two edges. Also, if we have exactly one outgoing edge, we can
1055 if (EDGE_COUNT (src
->succs
) >= 3
1056 /* Verify that all targets will be TARGET. Specifically, the
1057 edge that is not E must also go to TARGET. */
1058 || (EDGE_COUNT (src
->succs
) == 2
1059 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
1062 if (!onlyjump_p (insn
))
1064 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
1067 /* Avoid removing branch with side effects. */
1068 set
= single_set (insn
);
1069 if (!set
|| side_effects_p (set
))
1072 /* In case we zap a conditional jump, we'll need to kill
1073 the cc0 setter too. */
1075 if (HAVE_cc0
&& reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
1076 && only_sets_cc0_p (PREV_INSN (insn
)))
1077 kill_from
= PREV_INSN (insn
);
1079 /* See if we can create the fallthru edge. */
1080 if (in_cfglayout
|| can_fallthru (src
, target
))
1083 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
1086 /* Selectively unlink whole insn chain. */
1089 delete_insn_chain (kill_from
, BB_END (src
), false);
1090 remove_barriers_from_footer (src
);
1093 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
1097 /* If this already is simplejump, redirect it. */
1098 else if (simplejump_p (insn
))
1100 if (e
->dest
== target
)
1103 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
1104 INSN_UID (insn
), e
->dest
->index
, target
->index
);
1105 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1106 block_label (target
), 0))
1108 gcc_assert (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1113 /* Cannot do anything for target exit block. */
1114 else if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1117 /* Or replace possibly complicated jump insn by simple jump insn. */
1120 rtx_code_label
*target_label
= block_label (target
);
1123 rtx_jump_table_data
*table
;
1125 emit_jump_insn_after_noloc (targetm
.gen_jump (target_label
), insn
);
1126 JUMP_LABEL (BB_END (src
)) = target_label
;
1127 LABEL_NUSES (target_label
)++;
1129 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
1130 INSN_UID (insn
), INSN_UID (BB_END (src
)));
1133 delete_insn_chain (kill_from
, insn
, false);
1135 /* Recognize a tablejump that we are converting to a
1136 simple jump and remove its associated CODE_LABEL
1137 and ADDR_VEC or ADDR_DIFF_VEC. */
1138 if (tablejump_p (insn
, &label
, &table
))
1139 delete_insn_chain (label
, table
, false);
1141 barrier
= next_nonnote_nondebug_insn (BB_END (src
));
1142 if (!barrier
|| !BARRIER_P (barrier
))
1143 emit_barrier_after (BB_END (src
));
1146 if (barrier
!= NEXT_INSN (BB_END (src
)))
1148 /* Move the jump before barrier so that the notes
1149 which originally were or were created before jump table are
1150 inside the basic block. */
1151 rtx_insn
*new_insn
= BB_END (src
);
1153 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
1154 PREV_INSN (barrier
), src
);
1156 SET_NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
1157 SET_PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
1159 SET_NEXT_INSN (new_insn
) = barrier
;
1160 SET_NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
1162 SET_PREV_INSN (new_insn
) = PREV_INSN (barrier
);
1163 SET_PREV_INSN (barrier
) = new_insn
;
1168 /* Keep only one edge out and set proper flags. */
1169 if (!single_succ_p (src
))
1171 gcc_assert (single_succ_p (src
));
1173 e
= single_succ_edge (src
);
1175 e
->flags
= EDGE_FALLTHRU
;
1179 e
->probability
= profile_probability::always ();
1181 if (e
->dest
!= target
)
1182 redirect_edge_succ (e
, target
);
1186 /* Subroutine of redirect_branch_edge that tries to patch the jump
1187 instruction INSN so that it reaches block NEW. Do this
1188 only when it originally reached block OLD. Return true if this
1189 worked or the original target wasn't OLD, return false if redirection
1193 patch_jump_insn (rtx_insn
*insn
, rtx_insn
*old_label
, basic_block new_bb
)
1195 rtx_jump_table_data
*table
;
1197 /* Recognize a tablejump and adjust all matching cases. */
1198 if (tablejump_p (insn
, NULL
, &table
))
1202 rtx_code_label
*new_label
= block_label (new_bb
);
1204 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1206 vec
= table
->get_labels ();
1208 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
1209 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
1211 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
1212 --LABEL_NUSES (old_label
);
1213 ++LABEL_NUSES (new_label
);
1216 /* Handle casesi dispatch insns. */
1217 if ((tmp
= single_set (insn
)) != NULL
1218 && SET_DEST (tmp
) == pc_rtx
1219 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
1220 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
1221 && label_ref_label (XEXP (SET_SRC (tmp
), 2)) == old_label
)
1223 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
1225 --LABEL_NUSES (old_label
);
1226 ++LABEL_NUSES (new_label
);
1229 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
1231 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
1234 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1236 rtx_code_label
*new_label
= block_label (new_bb
);
1238 for (i
= 0; i
< n
; ++i
)
1240 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
1241 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
1242 if (XEXP (old_ref
, 0) == old_label
)
1244 ASM_OPERANDS_LABEL (tmp
, i
)
1245 = gen_rtx_LABEL_REF (Pmode
, new_label
);
1246 --LABEL_NUSES (old_label
);
1247 ++LABEL_NUSES (new_label
);
1251 if (JUMP_LABEL (insn
) == old_label
)
1253 JUMP_LABEL (insn
) = new_label
;
1254 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1256 remove_note (insn
, note
);
1260 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1262 remove_note (insn
, note
);
1263 if (JUMP_LABEL (insn
) != new_label
1264 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1265 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1267 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1269 XEXP (note
, 0) = new_label
;
1273 /* ?? We may play the games with moving the named labels from
1274 one basic block to the other in case only one computed_jump is
1276 if (computed_jump_p (insn
)
1277 /* A return instruction can't be redirected. */
1278 || returnjump_p (insn
))
1281 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1283 /* If the insn doesn't go where we think, we're confused. */
1284 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1286 /* If the substitution doesn't succeed, die. This can happen
1287 if the back end emitted unrecognizable instructions or if
1288 target is exit block on some arches. Or for crossing
1290 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1291 block_label (new_bb
), 0))
1293 gcc_assert (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
1294 || CROSSING_JUMP_P (insn
));
1303 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1306 redirect_branch_edge (edge e
, basic_block target
)
1308 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1309 basic_block src
= e
->src
;
1310 rtx_insn
*insn
= BB_END (src
);
1312 /* We can only redirect non-fallthru edges of jump insn. */
1313 if (e
->flags
& EDGE_FALLTHRU
)
1315 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1318 if (!currently_expanding_to_rtl
)
1320 if (!patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
), old_label
, target
))
1324 /* When expanding this BB might actually contain multiple
1325 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1326 Redirect all of those that match our label. */
1327 FOR_BB_INSNS (src
, insn
)
1328 if (JUMP_P (insn
) && !patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
),
1333 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1334 e
->src
->index
, e
->dest
->index
, target
->index
);
1336 if (e
->dest
!= target
)
1337 e
= redirect_edge_succ_nodup (e
, target
);
1342 /* Called when edge E has been redirected to a new destination,
1343 in order to update the region crossing flag on the edge and
1347 fixup_partition_crossing (edge e
)
1349 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
) || e
->dest
1350 == EXIT_BLOCK_PTR_FOR_FN (cfun
))
1352 /* If we redirected an existing edge, it may already be marked
1353 crossing, even though the new src is missing a reg crossing note.
1354 But make sure reg crossing note doesn't already exist before
1356 if (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
))
1358 e
->flags
|= EDGE_CROSSING
;
1359 if (JUMP_P (BB_END (e
->src
)))
1360 CROSSING_JUMP_P (BB_END (e
->src
)) = 1;
1362 else if (BB_PARTITION (e
->src
) == BB_PARTITION (e
->dest
))
1364 e
->flags
&= ~EDGE_CROSSING
;
1365 /* Remove the section crossing note from jump at end of
1366 src if it exists, and if no other successors are
1368 if (JUMP_P (BB_END (e
->src
)) && CROSSING_JUMP_P (BB_END (e
->src
)))
1370 bool has_crossing_succ
= false;
1373 FOR_EACH_EDGE (e2
, ei
, e
->src
->succs
)
1375 has_crossing_succ
|= (e2
->flags
& EDGE_CROSSING
);
1376 if (has_crossing_succ
)
1379 if (!has_crossing_succ
)
1380 CROSSING_JUMP_P (BB_END (e
->src
)) = 0;
1385 /* Called when block BB has been reassigned to the cold partition,
1386 because it is now dominated by another cold block,
1387 to ensure that the region crossing attributes are updated. */
1390 fixup_new_cold_bb (basic_block bb
)
1395 /* This is called when a hot bb is found to now be dominated
1396 by a cold bb and therefore needs to become cold. Therefore,
1397 its preds will no longer be region crossing. Any non-dominating
1398 preds that were previously hot would also have become cold
1399 in the caller for the same region. Any preds that were previously
1400 region-crossing will be adjusted in fixup_partition_crossing. */
1401 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1403 fixup_partition_crossing (e
);
1406 /* Possibly need to make bb's successor edges region crossing,
1407 or remove stale region crossing. */
1408 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1410 /* We can't have fall-through edges across partition boundaries.
1411 Note that force_nonfallthru will do any necessary partition
1412 boundary fixup by calling fixup_partition_crossing itself. */
1413 if ((e
->flags
& EDGE_FALLTHRU
)
1414 && BB_PARTITION (bb
) != BB_PARTITION (e
->dest
)
1415 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1416 force_nonfallthru (e
);
1418 fixup_partition_crossing (e
);
1422 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1423 expense of adding new instructions or reordering basic blocks.
1425 Function can be also called with edge destination equivalent to the TARGET.
1426 Then it should try the simplifications and do nothing if none is possible.
1428 Return edge representing the branch if transformation succeeded. Return NULL
1430 We still return NULL in case E already destinated TARGET and we didn't
1431 managed to simplify instruction stream. */
1434 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1437 basic_block src
= e
->src
;
1438 basic_block dest
= e
->dest
;
1440 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1446 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1448 df_set_bb_dirty (src
);
1449 fixup_partition_crossing (ret
);
1453 ret
= redirect_branch_edge (e
, target
);
1457 df_set_bb_dirty (src
);
1458 fixup_partition_crossing (ret
);
1462 /* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */
1465 emit_barrier_after_bb (basic_block bb
)
1467 rtx_barrier
*barrier
= emit_barrier_after (BB_END (bb
));
1468 gcc_assert (current_ir_type () == IR_RTL_CFGRTL
1469 || current_ir_type () == IR_RTL_CFGLAYOUT
);
1470 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
1472 rtx_insn
*insn
= unlink_insn_chain (barrier
, barrier
);
1476 rtx_insn
*footer_tail
= BB_FOOTER (bb
);
1478 while (NEXT_INSN (footer_tail
))
1479 footer_tail
= NEXT_INSN (footer_tail
);
1480 if (!BARRIER_P (footer_tail
))
1482 SET_NEXT_INSN (footer_tail
) = insn
;
1483 SET_PREV_INSN (insn
) = footer_tail
;
1487 BB_FOOTER (bb
) = insn
;
1491 /* Like force_nonfallthru below, but additionally performs redirection
1492 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1493 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1494 simple_return_rtx, indicating which kind of returnjump to create.
1495 It should be NULL otherwise. */
1498 force_nonfallthru_and_redirect (edge e
, basic_block target
, rtx jump_label
)
1500 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1503 int abnormal_edge_flags
= 0;
1504 bool asm_goto_edge
= false;
1507 /* In the case the last instruction is conditional jump to the next
1508 instruction, first redirect the jump itself and then continue
1509 by creating a basic block afterwards to redirect fallthru edge. */
1510 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
1511 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1512 && any_condjump_p (BB_END (e
->src
))
1513 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1516 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1519 redirected
= redirect_jump (as_a
<rtx_jump_insn
*> (BB_END (e
->src
)),
1520 block_label (target
), 0);
1521 gcc_assert (redirected
);
1523 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1526 int prob
= XINT (note
, 0);
1528 b
->probability
= profile_probability::from_reg_br_prob_note (prob
);
1529 e
->probability
-= e
->probability
;
1533 if (e
->flags
& EDGE_ABNORMAL
)
1535 /* Irritating special case - fallthru edge to the same block as abnormal
1537 We can't redirect abnormal edge, but we still can split the fallthru
1538 one and create separate abnormal edge to original destination.
1539 This allows bb-reorder to make such edge non-fallthru. */
1540 gcc_assert (e
->dest
== target
);
1541 abnormal_edge_flags
= e
->flags
& ~EDGE_FALLTHRU
;
1542 e
->flags
&= EDGE_FALLTHRU
;
1546 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1547 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1549 /* We can't redirect the entry block. Create an empty block
1550 at the start of the function which we use to add the new
1556 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
,
1557 ENTRY_BLOCK_PTR_FOR_FN (cfun
));
1558 bb
->count
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->count
;
1560 /* Make sure new block ends up in correct hot/cold section. */
1561 BB_COPY_PARTITION (bb
, e
->dest
);
1563 /* Change the existing edge's source to be the new block, and add
1564 a new edge from the entry block to the new block. */
1566 for (ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
1567 (tmp
= ei_safe_edge (ei
)); )
1571 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
->unordered_remove (ei
.index
);
1581 vec_safe_push (bb
->succs
, e
);
1582 make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun
), bb
,
1587 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1588 don't point to the target or fallthru label. */
1589 if (JUMP_P (BB_END (e
->src
))
1590 && target
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1591 && (e
->flags
& EDGE_FALLTHRU
)
1592 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1594 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1595 bool adjust_jump_target
= false;
1597 for (i
= 0; i
< n
; ++i
)
1599 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1601 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1602 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1603 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1604 adjust_jump_target
= true;
1606 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1607 asm_goto_edge
= true;
1609 if (adjust_jump_target
)
1611 rtx_insn
*insn
= BB_END (e
->src
);
1613 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1614 rtx_insn
*new_label
= BB_HEAD (target
);
1616 if (JUMP_LABEL (insn
) == old_label
)
1618 JUMP_LABEL (insn
) = new_label
;
1619 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1621 remove_note (insn
, note
);
1625 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1627 remove_note (insn
, note
);
1628 if (JUMP_LABEL (insn
) != new_label
1629 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1630 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1632 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1634 XEXP (note
, 0) = new_label
;
1638 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1641 profile_count count
= e
->count ();
1642 profile_probability probability
= e
->probability
;
1643 /* Create the new structures. */
1645 /* If the old block ended with a tablejump, skip its table
1646 by searching forward from there. Otherwise start searching
1647 forward from the last instruction of the old block. */
1648 rtx_jump_table_data
*table
;
1649 if (tablejump_p (BB_END (e
->src
), NULL
, &table
))
1652 new_head
= BB_END (e
->src
);
1653 new_head
= NEXT_INSN (new_head
);
1655 jump_block
= create_basic_block (new_head
, NULL
, e
->src
);
1656 jump_block
->count
= count
;
1658 /* Make sure new block ends up in correct hot/cold section. */
1660 BB_COPY_PARTITION (jump_block
, e
->src
);
1663 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1664 new_edge
->probability
= probability
;
1666 /* Redirect old edge. */
1667 redirect_edge_pred (e
, jump_block
);
1668 e
->probability
= profile_probability::always ();
1670 /* If e->src was previously region crossing, it no longer is
1671 and the reg crossing note should be removed. */
1672 fixup_partition_crossing (new_edge
);
1674 /* If asm goto has any label refs to target's label,
1675 add also edge from asm goto bb to target. */
1678 new_edge
->probability
= new_edge
->probability
.apply_scale (1, 2);
1679 jump_block
->count
= jump_block
->count
.apply_scale (1, 2);
1680 edge new_edge2
= make_edge (new_edge
->src
, target
,
1681 e
->flags
& ~EDGE_FALLTHRU
);
1682 new_edge2
->probability
= probability
- new_edge
->probability
;
1685 new_bb
= jump_block
;
1688 jump_block
= e
->src
;
1690 loc
= e
->goto_locus
;
1691 e
->flags
&= ~EDGE_FALLTHRU
;
1692 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1694 if (jump_label
== ret_rtx
)
1695 emit_jump_insn_after_setloc (targetm
.gen_return (),
1696 BB_END (jump_block
), loc
);
1699 gcc_assert (jump_label
== simple_return_rtx
);
1700 emit_jump_insn_after_setloc (targetm
.gen_simple_return (),
1701 BB_END (jump_block
), loc
);
1703 set_return_jump_label (BB_END (jump_block
));
1707 rtx_code_label
*label
= block_label (target
);
1708 emit_jump_insn_after_setloc (targetm
.gen_jump (label
),
1709 BB_END (jump_block
), loc
);
1710 JUMP_LABEL (BB_END (jump_block
)) = label
;
1711 LABEL_NUSES (label
)++;
1714 /* We might be in cfg layout mode, and if so, the following routine will
1715 insert the barrier correctly. */
1716 emit_barrier_after_bb (jump_block
);
1717 redirect_edge_succ_nodup (e
, target
);
1719 if (abnormal_edge_flags
)
1720 make_edge (src
, target
, abnormal_edge_flags
);
1722 df_mark_solutions_dirty ();
1723 fixup_partition_crossing (e
);
1727 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1728 (and possibly create new basic block) to make edge non-fallthru.
1729 Return newly created BB or NULL if none. */
1732 rtl_force_nonfallthru (edge e
)
1734 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1737 /* Redirect edge even at the expense of creating new jump insn or
1738 basic block. Return new basic block if created, NULL otherwise.
1739 Conversion must be possible. */
1742 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1744 if (redirect_edge_and_branch (e
, target
)
1745 || e
->dest
== target
)
1748 /* In case the edge redirection failed, try to force it to be non-fallthru
1749 and redirect newly created simplejump. */
1750 df_set_bb_dirty (e
->src
);
1751 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1754 /* The given edge should potentially be a fallthru edge. If that is in
1755 fact true, delete the jump and barriers that are in the way. */
1758 rtl_tidy_fallthru_edge (edge e
)
1761 basic_block b
= e
->src
, c
= b
->next_bb
;
1763 /* ??? In a late-running flow pass, other folks may have deleted basic
1764 blocks by nopping out blocks, leaving multiple BARRIERs between here
1765 and the target label. They ought to be chastised and fixed.
1767 We can also wind up with a sequence of undeletable labels between
1768 one block and the next.
1770 So search through a sequence of barriers, labels, and notes for
1771 the head of block C and assert that we really do fall through. */
1773 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1774 if (NONDEBUG_INSN_P (q
))
1777 /* Remove what will soon cease being the jump insn from the source block.
1778 If block B consisted only of this single jump, turn it into a deleted
1783 && (any_uncondjump_p (q
)
1784 || single_succ_p (b
)))
1787 rtx_jump_table_data
*table
;
1789 if (tablejump_p (q
, &label
, &table
))
1791 /* The label is likely mentioned in some instruction before
1792 the tablejump and might not be DCEd, so turn it into
1793 a note instead and move before the tablejump that is going to
1795 const char *name
= LABEL_NAME (label
);
1796 PUT_CODE (label
, NOTE
);
1797 NOTE_KIND (label
) = NOTE_INSN_DELETED_LABEL
;
1798 NOTE_DELETED_LABEL_NAME (label
) = name
;
1799 reorder_insns (label
, label
, PREV_INSN (q
));
1800 delete_insn (table
);
1803 /* If this was a conditional jump, we need to also delete
1804 the insn that set cc0. */
1805 if (HAVE_cc0
&& any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1810 /* Unconditional jumps with side-effects (i.e. which we can't just delete
1811 together with the barrier) should never have a fallthru edge. */
1812 else if (JUMP_P (q
) && any_uncondjump_p (q
))
1815 /* Selectively unlink the sequence. */
1816 if (q
!= PREV_INSN (BB_HEAD (c
)))
1817 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1819 e
->flags
|= EDGE_FALLTHRU
;
1822 /* Should move basic block BB after basic block AFTER. NIY. */
1825 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1826 basic_block after ATTRIBUTE_UNUSED
)
1831 /* Locate the last bb in the same partition as START_BB. */
1834 last_bb_in_partition (basic_block start_bb
)
1837 FOR_BB_BETWEEN (bb
, start_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
1839 if (BB_PARTITION (start_bb
) != BB_PARTITION (bb
->next_bb
))
1842 /* Return bb before the exit block. */
1846 /* Split a (typically critical) edge. Return the new block.
1847 The edge must not be abnormal.
1849 ??? The code generally expects to be called on critical edges.
1850 The case of a block ending in an unconditional jump to a
1851 block with multiple predecessors is not handled optimally. */
1854 rtl_split_edge (edge edge_in
)
1856 basic_block bb
, new_bb
;
1859 /* Abnormal edges cannot be split. */
1860 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1862 /* We are going to place the new block in front of edge destination.
1863 Avoid existence of fallthru predecessors. */
1864 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1866 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1869 force_nonfallthru (e
);
1872 /* Create the basic block note. */
1873 if (edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1874 before
= BB_HEAD (edge_in
->dest
);
1878 /* If this is a fall through edge to the exit block, the blocks might be
1879 not adjacent, and the right place is after the source. */
1880 if ((edge_in
->flags
& EDGE_FALLTHRU
)
1881 && edge_in
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1883 before
= NEXT_INSN (BB_END (edge_in
->src
));
1884 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1885 BB_COPY_PARTITION (bb
, edge_in
->src
);
1889 if (edge_in
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1891 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1892 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1896 basic_block after
= edge_in
->dest
->prev_bb
;
1897 /* If this is post-bb reordering, and the edge crosses a partition
1898 boundary, the new block needs to be inserted in the bb chain
1899 at the end of the src partition (since we put the new bb into
1900 that partition, see below). Otherwise we may end up creating
1901 an extra partition crossing in the chain, which is illegal.
1902 It can't go after the src, because src may have a fall-through
1903 to a different block. */
1904 if (crtl
->bb_reorder_complete
1905 && (edge_in
->flags
& EDGE_CROSSING
))
1907 after
= last_bb_in_partition (edge_in
->src
);
1908 before
= get_last_bb_insn (after
);
1909 /* The instruction following the last bb in partition should
1910 be a barrier, since it cannot end in a fall-through. */
1911 gcc_checking_assert (BARRIER_P (before
));
1912 before
= NEXT_INSN (before
);
1914 bb
= create_basic_block (before
, NULL
, after
);
1915 /* Put the split bb into the src partition, to avoid creating
1916 a situation where a cold bb dominates a hot bb, in the case
1917 where src is cold and dest is hot. The src will dominate
1918 the new bb (whereas it might not have dominated dest). */
1919 BB_COPY_PARTITION (bb
, edge_in
->src
);
1923 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1925 /* Can't allow a region crossing edge to be fallthrough. */
1926 if (BB_PARTITION (bb
) != BB_PARTITION (edge_in
->dest
)
1927 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1929 new_bb
= force_nonfallthru (single_succ_edge (bb
));
1930 gcc_assert (!new_bb
);
1933 /* For non-fallthru edges, we must adjust the predecessor's
1934 jump instruction to target our new block. */
1935 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1937 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1938 gcc_assert (redirected
);
1942 if (edge_in
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1944 /* For asm goto even splitting of fallthru edge might
1945 need insn patching, as other labels might point to the
1947 rtx_insn
*last
= BB_END (edge_in
->src
);
1950 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1951 && (extract_asm_operands (PATTERN (last
))
1952 || JUMP_LABEL (last
) == before
)
1953 && patch_jump_insn (last
, before
, bb
))
1954 df_set_bb_dirty (edge_in
->src
);
1956 redirect_edge_succ (edge_in
, bb
);
1962 /* Queue instructions for insertion on an edge between two basic blocks.
1963 The new instructions and basic blocks (if any) will not appear in the
1964 CFG until commit_edge_insertions is called. */
1967 insert_insn_on_edge (rtx pattern
, edge e
)
1969 /* We cannot insert instructions on an abnormal critical edge.
1970 It will be easier to find the culprit if we die now. */
1971 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1973 if (e
->insns
.r
== NULL_RTX
)
1976 push_to_sequence (e
->insns
.r
);
1978 emit_insn (pattern
);
1980 e
->insns
.r
= get_insns ();
1984 /* Update the CFG for the instructions queued on edge E. */
1987 commit_one_edge_insertion (edge e
)
1989 rtx_insn
*before
= NULL
, *after
= NULL
, *insns
, *tmp
, *last
;
1992 /* Pull the insns off the edge now since the edge might go away. */
1996 /* Figure out where to put these insns. If the destination has
1997 one predecessor, insert there. Except for the exit block. */
1998 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2002 /* Get the location correct wrt a code label, and "nice" wrt
2003 a basic block note, and before everything else. */
2006 tmp
= NEXT_INSN (tmp
);
2007 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
2008 tmp
= NEXT_INSN (tmp
);
2009 if (tmp
== BB_HEAD (bb
))
2012 after
= PREV_INSN (tmp
);
2014 after
= get_last_insn ();
2017 /* If the source has one successor and the edge is not abnormal,
2018 insert there. Except for the entry block.
2019 Don't do this if the predecessor ends in a jump other than
2020 unconditional simple jump. E.g. for asm goto that points all
2021 its labels at the fallthru basic block, we can't insert instructions
2022 before the asm goto, as the asm goto can have various of side effects,
2023 and can't emit instructions after the asm goto, as it must end
2025 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
2026 && single_succ_p (e
->src
)
2027 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2028 && (!JUMP_P (BB_END (e
->src
))
2029 || simplejump_p (BB_END (e
->src
))))
2033 /* It is possible to have a non-simple jump here. Consider a target
2034 where some forms of unconditional jumps clobber a register. This
2035 happens on the fr30 for example.
2037 We know this block has a single successor, so we can just emit
2038 the queued insns before the jump. */
2039 if (JUMP_P (BB_END (bb
)))
2040 before
= BB_END (bb
);
2043 /* We'd better be fallthru, or we've lost track of what's what. */
2044 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
2046 after
= BB_END (bb
);
2050 /* Otherwise we must split the edge. */
2053 bb
= split_edge (e
);
2055 /* If E crossed a partition boundary, we needed to make bb end in
2056 a region-crossing jump, even though it was originally fallthru. */
2057 if (JUMP_P (BB_END (bb
)))
2058 before
= BB_END (bb
);
2060 after
= BB_END (bb
);
2063 /* Now that we've found the spot, do the insertion. */
2066 emit_insn_before_noloc (insns
, before
, bb
);
2067 last
= prev_nonnote_insn (before
);
2070 last
= emit_insn_after_noloc (insns
, after
, bb
);
2072 if (returnjump_p (last
))
2074 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2075 This is not currently a problem because this only happens
2076 for the (single) epilogue, which already has a fallthru edge
2079 e
= single_succ_edge (bb
);
2080 gcc_assert (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
2081 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
2083 e
->flags
&= ~EDGE_FALLTHRU
;
2084 emit_barrier_after (last
);
2087 delete_insn (before
);
2090 gcc_assert (!JUMP_P (last
));
2093 /* Update the CFG for all queued instructions. */
2096 commit_edge_insertions (void)
2100 /* Optimization passes that invoke this routine can cause hot blocks
2101 previously reached by both hot and cold blocks to become dominated only
2102 by cold blocks. This will cause the verification below to fail,
2103 and lead to now cold code in the hot section. In some cases this
2104 may only be visible after newly unreachable blocks are deleted,
2105 which will be done by fixup_partitions. */
2106 fixup_partitions ();
2108 checking_verify_flow_info ();
2110 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR_FOR_FN (cfun
),
2111 EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
2116 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2118 commit_one_edge_insertion (e
);
2123 /* Print out RTL-specific basic block information (live information
2124 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
2125 documented in dumpfile.h. */
2128 rtl_dump_bb (FILE *outf
, basic_block bb
, int indent
, dump_flags_t flags
)
2132 s_indent
= (char *) alloca ((size_t) indent
+ 1);
2133 memset (s_indent
, ' ', (size_t) indent
);
2134 s_indent
[indent
] = '\0';
2136 if (df
&& (flags
& TDF_DETAILS
))
2138 df_dump_top (bb
, outf
);
2142 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
2144 rtx_insn
*last
= BB_END (bb
);
2146 last
= NEXT_INSN (last
);
2147 for (rtx_insn
*insn
= BB_HEAD (bb
); insn
!= last
; insn
= NEXT_INSN (insn
))
2149 if (flags
& TDF_DETAILS
)
2150 df_dump_insn_top (insn
, outf
);
2151 if (! (flags
& TDF_SLIM
))
2152 print_rtl_single (outf
, insn
);
2154 dump_insn_slim (outf
, insn
);
2155 if (flags
& TDF_DETAILS
)
2156 df_dump_insn_bottom (insn
, outf
);
2160 if (df
&& (flags
& TDF_DETAILS
))
2162 df_dump_bottom (bb
, outf
);
2168 /* Like dump_function_to_file, but for RTL. Print out dataflow information
2169 for the start of each basic block. FLAGS are the TDF_* masks documented
2173 print_rtl_with_bb (FILE *outf
, const rtx_insn
*rtx_first
, dump_flags_t flags
)
2175 const rtx_insn
*tmp_rtx
;
2177 fprintf (outf
, "(nil)\n");
2180 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
2181 int max_uid
= get_max_uid ();
2182 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
2183 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
2184 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
2187 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
2188 insns, but the CFG is not maintained so the basic block info
2189 is not reliable. Therefore it's omitted from the dumps. */
2190 if (! (cfun
->curr_properties
& PROP_cfg
))
2191 flags
&= ~TDF_BLOCKS
;
2194 df_dump_start (outf
);
2196 if (flags
& TDF_BLOCKS
)
2198 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2202 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
2203 end
[INSN_UID (BB_END (bb
))] = bb
;
2204 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
2206 enum bb_state state
= IN_MULTIPLE_BB
;
2208 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
2210 in_bb_p
[INSN_UID (x
)] = state
;
2212 if (x
== BB_END (bb
))
2218 for (tmp_rtx
= rtx_first
; tmp_rtx
!= NULL
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
2220 if (flags
& TDF_BLOCKS
)
2222 bb
= start
[INSN_UID (tmp_rtx
)];
2225 dump_bb_info (outf
, bb
, 0, dump_flags
, true, false);
2226 if (df
&& (flags
& TDF_DETAILS
))
2227 df_dump_top (bb
, outf
);
2230 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
2231 && !NOTE_P (tmp_rtx
)
2232 && !BARRIER_P (tmp_rtx
))
2233 fprintf (outf
, ";; Insn is not within a basic block\n");
2234 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
2235 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
2238 if (flags
& TDF_DETAILS
)
2239 df_dump_insn_top (tmp_rtx
, outf
);
2240 if (! (flags
& TDF_SLIM
))
2241 print_rtl_single (outf
, tmp_rtx
);
2243 dump_insn_slim (outf
, tmp_rtx
);
2244 if (flags
& TDF_DETAILS
)
2245 df_dump_insn_bottom (tmp_rtx
, outf
);
2247 if (flags
& TDF_BLOCKS
)
2249 bb
= end
[INSN_UID (tmp_rtx
)];
2252 dump_bb_info (outf
, bb
, 0, dump_flags
, false, true);
2253 if (df
&& (flags
& TDF_DETAILS
))
2254 df_dump_bottom (bb
, outf
);
2266 /* Update the branch probability of BB if a REG_BR_PROB is present. */
2269 update_br_prob_note (basic_block bb
)
2272 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
2273 if (!JUMP_P (BB_END (bb
)) || !BRANCH_EDGE (bb
)->probability
.initialized_p ())
2277 rtx
*note_link
, this_rtx
;
2279 note_link
= ®_NOTES (BB_END (bb
));
2280 for (this_rtx
= *note_link
; this_rtx
; this_rtx
= XEXP (this_rtx
, 1))
2281 if (this_rtx
== note
)
2283 *note_link
= XEXP (this_rtx
, 1);
2290 || XINT (note
, 0) == BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ())
2292 XINT (note
, 0) = BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ();
2295 /* Get the last insn associated with block BB (that includes barriers and
2296 tablejumps after BB). */
2298 get_last_bb_insn (basic_block bb
)
2300 rtx_jump_table_data
*table
;
2302 rtx_insn
*end
= BB_END (bb
);
2304 /* Include any jump table following the basic block. */
2305 if (tablejump_p (end
, NULL
, &table
))
2308 /* Include any barriers that may follow the basic block. */
2309 tmp
= next_nonnote_nondebug_insn_bb (end
);
2310 while (tmp
&& BARRIER_P (tmp
))
2313 tmp
= next_nonnote_nondebug_insn_bb (end
);
2319 /* Add all BBs reachable from entry via hot paths into the SET. */
2322 find_bbs_reachable_by_hot_paths (hash_set
<basic_block
> *set
)
2324 auto_vec
<basic_block
, 64> worklist
;
2326 set
->add (ENTRY_BLOCK_PTR_FOR_FN (cfun
));
2327 worklist
.safe_push (ENTRY_BLOCK_PTR_FOR_FN (cfun
));
2329 while (worklist
.length () > 0)
2331 basic_block bb
= worklist
.pop ();
2335 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2336 if (BB_PARTITION (e
->dest
) != BB_COLD_PARTITION
2337 && !set
->add (e
->dest
))
2338 worklist
.safe_push (e
->dest
);
2342 /* Sanity check partition hotness to ensure that basic blocks in
2343 Â the cold partition don't dominate basic blocks in the hot partition.
2344 If FLAG_ONLY is true, report violations as errors. Otherwise
2345 re-mark the dominated blocks as cold, since this is run after
2346 cfg optimizations that may make hot blocks previously reached
2347 by both hot and cold blocks now only reachable along cold paths. */
2349 static vec
<basic_block
>
2350 find_partition_fixes (bool flag_only
)
2353 vec
<basic_block
> bbs_in_cold_partition
= vNULL
;
2354 vec
<basic_block
> bbs_to_fix
= vNULL
;
2355 hash_set
<basic_block
> set
;
2357 /* Callers check this. */
2358 gcc_checking_assert (crtl
->has_bb_partition
);
2360 find_bbs_reachable_by_hot_paths (&set
);
2362 FOR_EACH_BB_FN (bb
, cfun
)
2363 if (!set
.contains (bb
)
2364 && BB_PARTITION (bb
) != BB_COLD_PARTITION
)
2367 error ("non-cold basic block %d reachable only "
2368 "by paths crossing the cold partition", bb
->index
);
2370 BB_SET_PARTITION (bb
, BB_COLD_PARTITION
);
2371 bbs_to_fix
.safe_push (bb
);
2372 bbs_in_cold_partition
.safe_push (bb
);
2378 /* Perform cleanup on the hot/cold bb partitioning after optimization
2379 passes that modify the cfg. */
2382 fixup_partitions (void)
2386 if (!crtl
->has_bb_partition
)
2389 /* Delete any blocks that became unreachable and weren't
2390 already cleaned up, for example during edge forwarding
2391 and convert_jumps_to_returns. This will expose more
2392 opportunities for fixing the partition boundaries here.
2393 Also, the calculation of the dominance graph during verification
2394 will assert if there are unreachable nodes. */
2395 delete_unreachable_blocks ();
2397 /* If there are partitions, do a sanity check on them: A basic block in
2398 Â a cold partition cannot dominate a basic block in a hot partition.
2399 Fixup any that now violate this requirement, as a result of edge
2400 forwarding and unreachable block deletion. Â */
2401 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (false);
2403 /* Do the partition fixup after all necessary blocks have been converted to
2404 cold, so that we only update the region crossings the minimum number of
2405 places, which can require forcing edges to be non fallthru. */
2406 while (! bbs_to_fix
.is_empty ())
2408 bb
= bbs_to_fix
.pop ();
2409 fixup_new_cold_bb (bb
);
2413 /* Verify, in the basic block chain, that there is at most one switch
2414 between hot/cold partitions. This condition will not be true until
2415 after reorder_basic_blocks is called. */
2418 verify_hot_cold_block_grouping (void)
2422 bool switched_sections
= false;
2423 int current_partition
= BB_UNPARTITIONED
;
2425 /* Even after bb reordering is complete, we go into cfglayout mode
2426 again (in compgoto). Ensure we don't call this before going back
2427 into linearized RTL when any layout fixes would have been committed. */
2428 if (!crtl
->bb_reorder_complete
2429 || current_ir_type () != IR_RTL_CFGRTL
)
2432 FOR_EACH_BB_FN (bb
, cfun
)
2434 if (current_partition
!= BB_UNPARTITIONED
2435 && BB_PARTITION (bb
) != current_partition
)
2437 if (switched_sections
)
2439 error ("multiple hot/cold transitions found (bb %i)",
2444 switched_sections
= true;
2446 if (!crtl
->has_bb_partition
)
2447 error ("partition found but function partition flag not set");
2449 current_partition
= BB_PARTITION (bb
);
2456 /* Perform several checks on the edges out of each block, such as
2457 the consistency of the branch probabilities, the correctness
2458 of hot/cold partition crossing edges, and the number of expected
2459 successor edges. Also verify that the dominance relationship
2460 between hot/cold blocks is sane. */
2463 rtl_verify_edges (void)
2468 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2470 int n_fallthru
= 0, n_branch
= 0, n_abnormal_call
= 0, n_sibcall
= 0;
2471 int n_eh
= 0, n_abnormal
= 0;
2472 edge e
, fallthru
= NULL
;
2475 bool has_crossing_edge
= false;
2477 if (JUMP_P (BB_END (bb
))
2478 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
2479 && EDGE_COUNT (bb
->succs
) >= 2
2480 && any_condjump_p (BB_END (bb
)))
2482 if (!BRANCH_EDGE (bb
)->probability
.initialized_p ())
2484 if (profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2486 error ("verify_flow_info: "
2487 "REG_BR_PROB is set but cfg probability is not");
2491 else if (XINT (note
, 0)
2492 != BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ()
2493 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2495 error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
2497 BRANCH_EDGE (bb
)->probability
.to_reg_br_prob_note ());
2502 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2506 if (e
->flags
& EDGE_FALLTHRU
)
2507 n_fallthru
++, fallthru
= e
;
2509 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
2510 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2511 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
));
2512 has_crossing_edge
|= is_crossing
;
2513 if (e
->flags
& EDGE_CROSSING
)
2517 error ("EDGE_CROSSING incorrectly set across same section");
2520 if (e
->flags
& EDGE_FALLTHRU
)
2522 error ("fallthru edge crosses section boundary in bb %i",
2526 if (e
->flags
& EDGE_EH
)
2528 error ("EH edge crosses section boundary in bb %i",
2532 if (JUMP_P (BB_END (bb
)) && !CROSSING_JUMP_P (BB_END (bb
)))
2534 error ("No region crossing jump at section boundary in bb %i",
2539 else if (is_crossing
)
2541 error ("EDGE_CROSSING missing across section boundary");
2545 if ((e
->flags
& ~(EDGE_DFS_BACK
2547 | EDGE_IRREDUCIBLE_LOOP
2550 | EDGE_PRESERVE
)) == 0)
2553 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2556 if (e
->flags
& EDGE_SIBCALL
)
2559 if (e
->flags
& EDGE_EH
)
2562 if (e
->flags
& EDGE_ABNORMAL
)
2566 if (!has_crossing_edge
2567 && JUMP_P (BB_END (bb
))
2568 && CROSSING_JUMP_P (BB_END (bb
)))
2570 print_rtl_with_bb (stderr
, get_insns (), TDF_BLOCKS
| TDF_DETAILS
);
2571 error ("Region crossing jump across same section in bb %i",
2576 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2578 error ("missing REG_EH_REGION note at the end of bb %i", bb
->index
);
2583 error ("too many exception handling edges in bb %i", bb
->index
);
2587 && (!JUMP_P (BB_END (bb
))
2588 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2589 || any_condjump_p (BB_END (bb
))))))
2591 error ("too many outgoing branch edges from bb %i", bb
->index
);
2594 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2596 error ("fallthru edge after unconditional jump in bb %i", bb
->index
);
2599 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2601 error ("wrong number of branch edges after unconditional jump"
2602 " in bb %i", bb
->index
);
2605 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2606 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2608 error ("wrong amount of branch edges after conditional jump"
2609 " in bb %i", bb
->index
);
2612 if (n_abnormal_call
&& !CALL_P (BB_END (bb
)))
2614 error ("abnormal call edges for non-call insn in bb %i", bb
->index
);
2617 if (n_sibcall
&& !CALL_P (BB_END (bb
)))
2619 error ("sibcall edges for non-call insn in bb %i", bb
->index
);
2622 if (n_abnormal
> n_eh
2623 && !(CALL_P (BB_END (bb
))
2624 && n_abnormal
== n_abnormal_call
+ n_sibcall
)
2625 && (!JUMP_P (BB_END (bb
))
2626 || any_condjump_p (BB_END (bb
))
2627 || any_uncondjump_p (BB_END (bb
))))
2629 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2634 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
2637 has_eh
= (e
->flags
& EDGE_EH
);
2638 if ((e
->flags
& EDGE_EH
) == has_eh
)
2640 error ("EH incoming edge mixed with non-EH incoming edges "
2641 "in bb %i", bb
->index
);
2647 /* If there are partitions, do a sanity check on them: A basic block in
2648 Â a cold partition cannot dominate a basic block in a hot partition. Â */
2649 if (crtl
->has_bb_partition
&& !err
2650 && current_ir_type () == IR_RTL_CFGLAYOUT
)
2652 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (true);
2653 err
= !bbs_to_fix
.is_empty ();
2660 /* Checks on the instructions within blocks. Currently checks that each
2661 block starts with a basic block note, and that basic block notes and
2662 control flow jumps are not found in the middle of the block. */
2665 rtl_verify_bb_insns (void)
2671 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2673 /* Now check the header of basic
2674 block. It ought to contain optional CODE_LABEL followed
2675 by NOTE_BASIC_BLOCK. */
2679 if (BB_END (bb
) == x
)
2681 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2689 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2691 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2696 if (BB_END (bb
) == x
)
2697 /* Do checks for empty blocks here. */
2700 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2702 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2704 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2705 INSN_UID (x
), bb
->index
);
2709 if (x
== BB_END (bb
))
2712 if (control_flow_insn_p (x
))
2714 error ("in basic block %d:", bb
->index
);
2715 fatal_insn ("flow control insn inside a basic block", x
);
2724 /* Verify that block pointers for instructions in basic blocks, headers and
2725 footers are set appropriately. */
2728 rtl_verify_bb_pointers (void)
2733 /* Check the general integrity of the basic blocks. */
2734 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2738 if (!(bb
->flags
& BB_RTL
))
2740 error ("BB_RTL flag not set for block %d", bb
->index
);
2744 FOR_BB_INSNS (bb
, insn
)
2745 if (BLOCK_FOR_INSN (insn
) != bb
)
2747 error ("insn %d basic block pointer is %d, should be %d",
2749 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
2754 for (insn
= BB_HEADER (bb
); insn
; insn
= NEXT_INSN (insn
))
2755 if (!BARRIER_P (insn
)
2756 && BLOCK_FOR_INSN (insn
) != NULL
)
2758 error ("insn %d in header of bb %d has non-NULL basic block",
2759 INSN_UID (insn
), bb
->index
);
2762 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2763 if (!BARRIER_P (insn
)
2764 && BLOCK_FOR_INSN (insn
) != NULL
)
2766 error ("insn %d in footer of bb %d has non-NULL basic block",
2767 INSN_UID (insn
), bb
->index
);
2776 /* Verify the CFG and RTL consistency common for both underlying RTL and
2779 Currently it does following checks:
2781 - overlapping of basic blocks
2782 - insns with wrong BLOCK_FOR_INSN pointers
2783 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2784 - tails of basic blocks (ensure that boundary is necessary)
2785 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2786 and NOTE_INSN_BASIC_BLOCK
2787 - verify that no fall_thru edge crosses hot/cold partition boundaries
2788 - verify that there are no pending RTL branch predictions
2789 - verify that hot blocks are not dominated by cold blocks
2791 In future it can be extended check a lot of other stuff as well
2792 (reachability of basic blocks, life information, etc. etc.). */
2795 rtl_verify_flow_info_1 (void)
2799 err
|= rtl_verify_bb_pointers ();
2801 err
|= rtl_verify_bb_insns ();
2803 err
|= rtl_verify_edges ();
2808 /* Walk the instruction chain and verify that bb head/end pointers
2809 are correct, and that instructions are in exactly one bb and have
2810 correct block pointers. */
2813 rtl_verify_bb_insn_chain (void)
2818 rtx_insn
*last_head
= get_last_insn ();
2819 basic_block
*bb_info
;
2820 const int max_uid
= get_max_uid ();
2822 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2824 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2826 rtx_insn
*head
= BB_HEAD (bb
);
2827 rtx_insn
*end
= BB_END (bb
);
2829 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2831 /* Verify the end of the basic block is in the INSN chain. */
2835 /* And that the code outside of basic blocks has NULL bb field. */
2837 && BLOCK_FOR_INSN (x
) != NULL
)
2839 error ("insn %d outside of basic blocks has non-NULL bb field",
2847 error ("end insn %d for block %d not found in the insn stream",
2848 INSN_UID (end
), bb
->index
);
2852 /* Work backwards from the end to the head of the basic block
2853 to verify the head is in the RTL chain. */
2854 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2856 /* While walking over the insn chain, verify insns appear
2857 in only one basic block. */
2858 if (bb_info
[INSN_UID (x
)] != NULL
)
2860 error ("insn %d is in multiple basic blocks (%d and %d)",
2861 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2865 bb_info
[INSN_UID (x
)] = bb
;
2872 error ("head insn %d for block %d not found in the insn stream",
2873 INSN_UID (head
), bb
->index
);
2877 last_head
= PREV_INSN (x
);
2880 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2882 /* Check that the code before the first basic block has NULL
2885 && BLOCK_FOR_INSN (x
) != NULL
)
2887 error ("insn %d outside of basic blocks has non-NULL bb field",
2897 /* Verify that fallthru edges point to adjacent blocks in layout order and
2898 that barriers exist after non-fallthru blocks. */
2901 rtl_verify_fallthru (void)
2906 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2910 e
= find_fallthru_edge (bb
->succs
);
2915 /* Ensure existence of barrier in BB with no fallthru edges. */
2916 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2918 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2920 error ("missing barrier after block %i", bb
->index
);
2924 if (BARRIER_P (insn
))
2928 else if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2929 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2933 if (e
->src
->next_bb
!= e
->dest
)
2936 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2937 e
->src
->index
, e
->dest
->index
);
2941 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2942 insn
= NEXT_INSN (insn
))
2943 if (BARRIER_P (insn
) || NONDEBUG_INSN_P (insn
))
2945 error ("verify_flow_info: Incorrect fallthru %i->%i",
2946 e
->src
->index
, e
->dest
->index
);
2947 fatal_insn ("wrong insn in the fallthru edge", insn
);
2956 /* Verify that blocks are laid out in consecutive order. While walking the
2957 instructions, verify that all expected instructions are inside the basic
2958 blocks, and that all returns are followed by barriers. */
2961 rtl_verify_bb_layout (void)
2967 rtx_insn
* const rtx_first
= get_insns ();
2968 basic_block last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
), curr_bb
= NULL
;
2972 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2974 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2976 bb
= NOTE_BASIC_BLOCK (x
);
2979 if (bb
!= last_bb_seen
->next_bb
)
2980 internal_error ("basic blocks not laid down consecutively");
2982 curr_bb
= last_bb_seen
= bb
;
2987 switch (GET_CODE (x
))
2994 /* An ADDR_VEC is placed outside any basic block. */
2996 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2999 /* But in any case, non-deletable labels can appear anywhere. */
3003 fatal_insn ("insn outside basic block", x
);
3008 && returnjump_p (x
) && ! condjump_p (x
)
3009 && ! ((y
= next_nonnote_nondebug_insn (x
))
3011 fatal_insn ("return not followed by barrier", x
);
3013 if (curr_bb
&& x
== BB_END (curr_bb
))
3017 if (num_bb_notes
!= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
)
3019 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
3020 num_bb_notes
, n_basic_blocks_for_fn (cfun
));
3025 /* Verify the CFG and RTL consistency common for both underlying RTL and
3026 cfglayout RTL, plus consistency checks specific to linearized RTL mode.
3028 Currently it does following checks:
3029 - all checks of rtl_verify_flow_info_1
3030 - test head/end pointers
3031 - check that blocks are laid out in consecutive order
3032 - check that all insns are in the basic blocks
3033 (except the switch handling code, barriers and notes)
3034 - check that all returns are followed by barriers
3035 - check that all fallthru edge points to the adjacent blocks
3036 - verify that there is a single hot/cold partition boundary after bbro */
3039 rtl_verify_flow_info (void)
3043 err
|= rtl_verify_flow_info_1 ();
3045 err
|= rtl_verify_bb_insn_chain ();
3047 err
|= rtl_verify_fallthru ();
3049 err
|= rtl_verify_bb_layout ();
3051 err
|= verify_hot_cold_block_grouping ();
3056 /* Assume that the preceding pass has possibly eliminated jump instructions
3057 or converted the unconditional jumps. Eliminate the edges from CFG.
3058 Return true if any edges are eliminated. */
3061 purge_dead_edges (basic_block bb
)
3064 rtx_insn
*insn
= BB_END (bb
);
3066 bool purged
= false;
3070 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
3072 insn
= PREV_INSN (insn
);
3073 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
3075 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
3076 if (NONJUMP_INSN_P (insn
)
3077 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
3081 if (! may_trap_p (PATTERN (insn
))
3082 || ((eqnote
= find_reg_equal_equiv_note (insn
))
3083 && ! may_trap_p (XEXP (eqnote
, 0))))
3084 remove_note (insn
, note
);
3087 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
3088 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3090 bool remove
= false;
3092 /* There are three types of edges we need to handle correctly here: EH
3093 edges, abnormal call EH edges, and abnormal call non-EH edges. The
3094 latter can appear when nonlocal gotos are used. */
3095 if (e
->flags
& EDGE_ABNORMAL_CALL
)
3099 else if (can_nonlocal_goto (insn
))
3101 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3103 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
3108 else if (e
->flags
& EDGE_EH
)
3109 remove
= !can_throw_internal (insn
);
3114 df_set_bb_dirty (bb
);
3127 /* We do care only about conditional jumps and simplejumps. */
3128 if (!any_condjump_p (insn
)
3129 && !returnjump_p (insn
)
3130 && !simplejump_p (insn
))
3133 /* Branch probability/prediction notes are defined only for
3134 condjumps. We've possibly turned condjump into simplejump. */
3135 if (simplejump_p (insn
))
3137 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3139 remove_note (insn
, note
);
3140 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
3141 remove_note (insn
, note
);
3144 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3146 /* Avoid abnormal flags to leak from computed jumps turned
3147 into simplejumps. */
3149 e
->flags
&= ~EDGE_ABNORMAL
;
3151 /* See if this edge is one we should keep. */
3152 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
3153 /* A conditional jump can fall through into the next
3154 block, so we should keep the edge. */
3159 else if (e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
3160 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
3161 /* If the destination block is the target of the jump,
3167 else if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
3168 && returnjump_p (insn
))
3169 /* If the destination block is the exit block, and this
3170 instruction is a return, then keep the edge. */
3175 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3176 /* Keep the edges that correspond to exceptions thrown by
3177 this instruction and rematerialize the EDGE_ABNORMAL
3178 flag we just cleared above. */
3180 e
->flags
|= EDGE_ABNORMAL
;
3185 /* We do not need this edge. */
3186 df_set_bb_dirty (bb
);
3191 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
3195 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
3200 /* Redistribute probabilities. */
3201 if (single_succ_p (bb
))
3203 single_succ_edge (bb
)->probability
= profile_probability::always ();
3207 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3211 b
= BRANCH_EDGE (bb
);
3212 f
= FALLTHRU_EDGE (bb
);
3213 b
->probability
= profile_probability::from_reg_br_prob_note
3215 f
->probability
= b
->probability
.invert ();
3220 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
3222 /* First, there should not be any EH or ABCALL edges resulting
3223 from non-local gotos and the like. If there were, we shouldn't
3224 have created the sibcall in the first place. Second, there
3225 should of course never have been a fallthru edge. */
3226 gcc_assert (single_succ_p (bb
));
3227 gcc_assert (single_succ_edge (bb
)->flags
3228 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
3233 /* If we don't see a jump insn, we don't know exactly why the block would
3234 have been broken at this point. Look for a simple, non-fallthru edge,
3235 as these are only created by conditional branches. If we find such an
3236 edge we know that there used to be a jump here and can then safely
3237 remove all non-fallthru edges. */
3239 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3240 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
3249 /* Remove all but the fake and fallthru edges. The fake edge may be
3250 the only successor for this block in the case of noreturn
3252 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3254 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
3256 df_set_bb_dirty (bb
);
3264 gcc_assert (single_succ_p (bb
));
3266 single_succ_edge (bb
)->probability
= profile_probability::always ();
3269 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
3274 /* Search all basic blocks for potentially dead edges and purge them. Return
3275 true if some edge has been eliminated. */
3278 purge_all_dead_edges (void)
3283 FOR_EACH_BB_FN (bb
, cfun
)
3285 bool purged_here
= purge_dead_edges (bb
);
3287 purged
|= purged_here
;
3293 /* This is used by a few passes that emit some instructions after abnormal
3294 calls, moving the basic block's end, while they in fact do want to emit
3295 them on the fallthru edge. Look for abnormal call edges, find backward
3296 the call in the block and insert the instructions on the edge instead.
3298 Similarly, handle instructions throwing exceptions internally.
3300 Return true when instructions have been found and inserted on edges. */
3303 fixup_abnormal_edges (void)
3305 bool inserted
= false;
3308 FOR_EACH_BB_FN (bb
, cfun
)
3313 /* Look for cases we are interested in - calls or instructions causing
3315 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3316 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
3317 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
3318 == (EDGE_ABNORMAL
| EDGE_EH
)))
3321 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
3325 /* Get past the new insns generated. Allow notes, as the insns
3326 may be already deleted. */
3328 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
3329 && !can_throw_internal (insn
)
3330 && insn
!= BB_HEAD (bb
))
3331 insn
= PREV_INSN (insn
);
3333 if (CALL_P (insn
) || can_throw_internal (insn
))
3335 rtx_insn
*stop
, *next
;
3337 e
= find_fallthru_edge (bb
->succs
);
3339 stop
= NEXT_INSN (BB_END (bb
));
3342 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
3344 next
= NEXT_INSN (insn
);
3349 /* Sometimes there's still the return value USE.
3350 If it's placed after a trapping call (i.e. that
3351 call is the last insn anyway), we have no fallthru
3352 edge. Simply delete this use and don't try to insert
3353 on the non-existent edge.
3354 Similarly, sometimes a call that can throw is
3355 followed in the source with __builtin_unreachable (),
3356 meaning that there is UB if the call returns rather
3357 than throws. If there weren't any instructions
3358 following such calls before, supposedly even the ones
3359 we've deleted aren't significant and can be
3363 /* We're not deleting it, we're moving it. */
3364 insn
->set_undeleted ();
3365 SET_PREV_INSN (insn
) = NULL_RTX
;
3366 SET_NEXT_INSN (insn
) = NULL_RTX
;
3368 insert_insn_on_edge (insn
, e
);
3372 else if (!BARRIER_P (insn
))
3373 set_block_for_insn (insn
, NULL
);
3377 /* It may be that we don't find any trapping insn. In this
3378 case we discovered quite late that the insn that had been
3379 marked as can_throw_internal in fact couldn't trap at all.
3380 So we should in fact delete the EH edges out of the block. */
3382 purge_dead_edges (bb
);
3389 /* Cut the insns from FIRST to LAST out of the insns stream. */
3392 unlink_insn_chain (rtx_insn
*first
, rtx_insn
*last
)
3394 rtx_insn
*prevfirst
= PREV_INSN (first
);
3395 rtx_insn
*nextlast
= NEXT_INSN (last
);
3397 SET_PREV_INSN (first
) = NULL
;
3398 SET_NEXT_INSN (last
) = NULL
;
3400 SET_NEXT_INSN (prevfirst
) = nextlast
;
3402 SET_PREV_INSN (nextlast
) = prevfirst
;
3404 set_last_insn (prevfirst
);
3406 set_first_insn (nextlast
);
3410 /* Skip over inter-block insns occurring after BB which are typically
3411 associated with BB (e.g., barriers). If there are any such insns,
3412 we return the last one. Otherwise, we return the end of BB. */
3415 skip_insns_after_block (basic_block bb
)
3417 rtx_insn
*insn
, *last_insn
, *next_head
, *prev
;
3420 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3421 next_head
= BB_HEAD (bb
->next_bb
);
3423 for (last_insn
= insn
= BB_END (bb
); (insn
= NEXT_INSN (insn
)) != 0; )
3425 if (insn
== next_head
)
3428 switch (GET_CODE (insn
))
3435 switch (NOTE_KIND (insn
))
3437 case NOTE_INSN_BLOCK_END
:
3447 if (NEXT_INSN (insn
)
3448 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
3450 insn
= NEXT_INSN (insn
);
3463 /* It is possible to hit contradictory sequence. For instance:
3469 Where barrier belongs to jump_insn, but the note does not. This can be
3470 created by removing the basic block originally following
3471 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
3473 for (insn
= last_insn
; insn
!= BB_END (bb
); insn
= prev
)
3475 prev
= PREV_INSN (insn
);
3477 switch (NOTE_KIND (insn
))
3479 case NOTE_INSN_BLOCK_END
:
3482 case NOTE_INSN_DELETED
:
3483 case NOTE_INSN_DELETED_LABEL
:
3484 case NOTE_INSN_DELETED_DEBUG_LABEL
:
3487 reorder_insns (insn
, insn
, last_insn
);
3494 /* Locate or create a label for a given basic block. */
3497 label_for_bb (basic_block bb
)
3499 rtx_insn
*label
= BB_HEAD (bb
);
3501 if (!LABEL_P (label
))
3504 fprintf (dump_file
, "Emitting label for block %d\n", bb
->index
);
3506 label
= block_label (bb
);
3512 /* Locate the effective beginning and end of the insn chain for each
3513 block, as defined by skip_insns_after_block above. */
3516 record_effective_endpoints (void)
3518 rtx_insn
*next_insn
;
3522 for (insn
= get_insns ();
3525 && NOTE_KIND (insn
) != NOTE_INSN_BASIC_BLOCK
;
3526 insn
= NEXT_INSN (insn
))
3528 /* No basic blocks at all? */
3531 if (PREV_INSN (insn
))
3532 cfg_layout_function_header
=
3533 unlink_insn_chain (get_insns (), PREV_INSN (insn
));
3535 cfg_layout_function_header
= NULL
;
3537 next_insn
= get_insns ();
3538 FOR_EACH_BB_FN (bb
, cfun
)
3542 if (PREV_INSN (BB_HEAD (bb
)) && next_insn
!= BB_HEAD (bb
))
3543 BB_HEADER (bb
) = unlink_insn_chain (next_insn
,
3544 PREV_INSN (BB_HEAD (bb
)));
3545 end
= skip_insns_after_block (bb
);
3546 if (NEXT_INSN (BB_END (bb
)) && BB_END (bb
) != end
)
3547 BB_FOOTER (bb
) = unlink_insn_chain (NEXT_INSN (BB_END (bb
)), end
);
3548 next_insn
= NEXT_INSN (BB_END (bb
));
3551 cfg_layout_function_footer
= next_insn
;
3552 if (cfg_layout_function_footer
)
3553 cfg_layout_function_footer
= unlink_insn_chain (cfg_layout_function_footer
, get_last_insn ());
3558 const pass_data pass_data_into_cfg_layout_mode
=
3560 RTL_PASS
, /* type */
3561 "into_cfglayout", /* name */
3562 OPTGROUP_NONE
, /* optinfo_flags */
3564 0, /* properties_required */
3565 PROP_cfglayout
, /* properties_provided */
3566 0, /* properties_destroyed */
3567 0, /* todo_flags_start */
3568 0, /* todo_flags_finish */
3571 class pass_into_cfg_layout_mode
: public rtl_opt_pass
3574 pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3575 : rtl_opt_pass (pass_data_into_cfg_layout_mode
, ctxt
)
3578 /* opt_pass methods: */
3579 virtual unsigned int execute (function
*)
3581 cfg_layout_initialize (0);
3585 }; // class pass_into_cfg_layout_mode
3590 make_pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3592 return new pass_into_cfg_layout_mode (ctxt
);
3597 const pass_data pass_data_outof_cfg_layout_mode
=
3599 RTL_PASS
, /* type */
3600 "outof_cfglayout", /* name */
3601 OPTGROUP_NONE
, /* optinfo_flags */
3603 0, /* properties_required */
3604 0, /* properties_provided */
3605 PROP_cfglayout
, /* properties_destroyed */
3606 0, /* todo_flags_start */
3607 0, /* todo_flags_finish */
3610 class pass_outof_cfg_layout_mode
: public rtl_opt_pass
3613 pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3614 : rtl_opt_pass (pass_data_outof_cfg_layout_mode
, ctxt
)
3617 /* opt_pass methods: */
3618 virtual unsigned int execute (function
*);
3620 }; // class pass_outof_cfg_layout_mode
3623 pass_outof_cfg_layout_mode::execute (function
*fun
)
3627 FOR_EACH_BB_FN (bb
, fun
)
3628 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (fun
))
3629 bb
->aux
= bb
->next_bb
;
3631 cfg_layout_finalize ();
3639 make_pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3641 return new pass_outof_cfg_layout_mode (ctxt
);
3645 /* Link the basic blocks in the correct order, compacting the basic
3646 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3647 function also clears the basic block header and footer fields.
3649 This function is usually called after a pass (e.g. tracer) finishes
3650 some transformations while in cfglayout mode. The required sequence
3651 of the basic blocks is in a linked list along the bb->aux field.
3652 This functions re-links the basic block prev_bb and next_bb pointers
3653 accordingly, and it compacts and renumbers the blocks.
3655 FIXME: This currently works only for RTL, but the only RTL-specific
3656 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3657 to GIMPLE a long time ago, but it doesn't relink the basic block
3658 chain. It could do that (to give better initial RTL) if this function
3659 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3662 relink_block_chain (bool stay_in_cfglayout_mode
)
3664 basic_block bb
, prev_bb
;
3667 /* Maybe dump the re-ordered sequence. */
3670 fprintf (dump_file
, "Reordered sequence:\n");
3671 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
, index
=
3674 bb
= (basic_block
) bb
->aux
, index
++)
3676 fprintf (dump_file
, " %i ", index
);
3677 if (get_bb_original (bb
))
3678 fprintf (dump_file
, "duplicate of %i ",
3679 get_bb_original (bb
)->index
);
3680 else if (forwarder_block_p (bb
)
3681 && !LABEL_P (BB_HEAD (bb
)))
3682 fprintf (dump_file
, "compensation ");
3684 fprintf (dump_file
, "bb %i ", bb
->index
);
3688 /* Now reorder the blocks. */
3689 prev_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
3690 bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3691 for (; bb
; prev_bb
= bb
, bb
= (basic_block
) bb
->aux
)
3693 bb
->prev_bb
= prev_bb
;
3694 prev_bb
->next_bb
= bb
;
3696 prev_bb
->next_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
3697 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
= prev_bb
;
3699 /* Then, clean up the aux fields. */
3700 FOR_ALL_BB_FN (bb
, cfun
)
3703 if (!stay_in_cfglayout_mode
)
3704 BB_HEADER (bb
) = BB_FOOTER (bb
) = NULL
;
3707 /* Maybe reset the original copy tables, they are not valid anymore
3708 when we renumber the basic blocks in compact_blocks. If we are
3709 are going out of cfglayout mode, don't re-allocate the tables. */
3710 if (original_copy_tables_initialized_p ())
3711 free_original_copy_tables ();
3712 if (stay_in_cfglayout_mode
)
3713 initialize_original_copy_tables ();
3715 /* Finally, put basic_block_info in the new order. */
3720 /* Given a reorder chain, rearrange the code to match. */
3723 fixup_reorder_chain (void)
3726 rtx_insn
*insn
= NULL
;
3728 if (cfg_layout_function_header
)
3730 set_first_insn (cfg_layout_function_header
);
3731 insn
= cfg_layout_function_header
;
3732 while (NEXT_INSN (insn
))
3733 insn
= NEXT_INSN (insn
);
3736 /* First do the bulk reordering -- rechain the blocks without regard to
3737 the needed changes to jumps and labels. */
3739 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3745 SET_NEXT_INSN (insn
) = BB_HEADER (bb
);
3747 set_first_insn (BB_HEADER (bb
));
3748 SET_PREV_INSN (BB_HEADER (bb
)) = insn
;
3749 insn
= BB_HEADER (bb
);
3750 while (NEXT_INSN (insn
))
3751 insn
= NEXT_INSN (insn
);
3754 SET_NEXT_INSN (insn
) = BB_HEAD (bb
);
3756 set_first_insn (BB_HEAD (bb
));
3757 SET_PREV_INSN (BB_HEAD (bb
)) = insn
;
3761 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
3762 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
3763 while (NEXT_INSN (insn
))
3764 insn
= NEXT_INSN (insn
);
3768 SET_NEXT_INSN (insn
) = cfg_layout_function_footer
;
3769 if (cfg_layout_function_footer
)
3770 SET_PREV_INSN (cfg_layout_function_footer
) = insn
;
3772 while (NEXT_INSN (insn
))
3773 insn
= NEXT_INSN (insn
);
3775 set_last_insn (insn
);
3777 verify_insn_chain ();
3779 /* Now add jumps and labels as needed to match the blocks new
3782 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3785 edge e_fall
, e_taken
, e
;
3786 rtx_insn
*bb_end_insn
;
3787 rtx ret_label
= NULL_RTX
;
3791 if (EDGE_COUNT (bb
->succs
) == 0)
3794 /* Find the old fallthru edge, and another non-EH edge for
3796 e_taken
= e_fall
= NULL
;
3798 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3799 if (e
->flags
& EDGE_FALLTHRU
)
3801 else if (! (e
->flags
& EDGE_EH
))
3804 bb_end_insn
= BB_END (bb
);
3805 if (rtx_jump_insn
*bb_end_jump
= dyn_cast
<rtx_jump_insn
*> (bb_end_insn
))
3807 ret_label
= JUMP_LABEL (bb_end_jump
);
3808 if (any_condjump_p (bb_end_jump
))
3810 /* This might happen if the conditional jump has side
3811 effects and could therefore not be optimized away.
3812 Make the basic block to end with a barrier in order
3813 to prevent rtl_verify_flow_info from complaining. */
3816 gcc_assert (!onlyjump_p (bb_end_jump
)
3817 || returnjump_p (bb_end_jump
)
3818 || (e_taken
->flags
& EDGE_CROSSING
));
3819 emit_barrier_after (bb_end_jump
);
3823 /* If the old fallthru is still next, nothing to do. */
3824 if (bb
->aux
== e_fall
->dest
3825 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3828 /* The degenerated case of conditional jump jumping to the next
3829 instruction can happen for jumps with side effects. We need
3830 to construct a forwarder block and this will be done just
3831 fine by force_nonfallthru below. */
3835 /* There is another special case: if *neither* block is next,
3836 such as happens at the very end of a function, then we'll
3837 need to add a new unconditional jump. Choose the taken
3838 edge based on known or assumed probability. */
3839 else if (bb
->aux
!= e_taken
->dest
)
3841 rtx note
= find_reg_note (bb_end_jump
, REG_BR_PROB
, 0);
3844 && profile_probability::from_reg_br_prob_note
3845 (XINT (note
, 0)) < profile_probability::even ()
3846 && invert_jump (bb_end_jump
,
3848 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3850 : label_for_bb (e_fall
->dest
)), 0))
3852 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3853 gcc_checking_assert (could_fall_through
3854 (e_taken
->src
, e_taken
->dest
));
3855 e_taken
->flags
|= EDGE_FALLTHRU
;
3856 update_br_prob_note (bb
);
3857 e
= e_fall
, e_fall
= e_taken
, e_taken
= e
;
3861 /* If the "jumping" edge is a crossing edge, and the fall
3862 through edge is non-crossing, leave things as they are. */
3863 else if ((e_taken
->flags
& EDGE_CROSSING
)
3864 && !(e_fall
->flags
& EDGE_CROSSING
))
3867 /* Otherwise we can try to invert the jump. This will
3868 basically never fail, however, keep up the pretense. */
3869 else if (invert_jump (bb_end_jump
,
3871 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3873 : label_for_bb (e_fall
->dest
)), 0))
3875 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3876 gcc_checking_assert (could_fall_through
3877 (e_taken
->src
, e_taken
->dest
));
3878 e_taken
->flags
|= EDGE_FALLTHRU
;
3879 update_br_prob_note (bb
);
3880 if (LABEL_NUSES (ret_label
) == 0
3881 && single_pred_p (e_taken
->dest
))
3882 delete_insn (as_a
<rtx_insn
*> (ret_label
));
3886 else if (extract_asm_operands (PATTERN (bb_end_insn
)) != NULL
)
3888 /* If the old fallthru is still next or if
3889 asm goto doesn't have a fallthru (e.g. when followed by
3890 __builtin_unreachable ()), nothing to do. */
3892 || bb
->aux
== e_fall
->dest
3893 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3896 /* Otherwise we'll have to use the fallthru fixup below. */
3900 /* Otherwise we have some return, switch or computed
3901 jump. In the 99% case, there should not have been a
3903 gcc_assert (returnjump_p (bb_end_insn
) || !e_fall
);
3909 /* No fallthru implies a noreturn function with EH edges, or
3910 something similarly bizarre. In any case, we don't need to
3915 /* If the fallthru block is still next, nothing to do. */
3916 if (bb
->aux
== e_fall
->dest
)
3919 /* A fallthru to exit block. */
3920 if (e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3924 /* We got here if we need to add a new jump insn.
3925 Note force_nonfallthru can delete E_FALL and thus we have to
3926 save E_FALL->src prior to the call to force_nonfallthru. */
3927 nb
= force_nonfallthru_and_redirect (e_fall
, e_fall
->dest
, ret_label
);
3932 /* Don't process this new block. */
3937 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3939 /* Annoying special case - jump around dead jumptables left in the code. */
3940 FOR_EACH_BB_FN (bb
, cfun
)
3942 edge e
= find_fallthru_edge (bb
->succs
);
3944 if (e
&& !can_fallthru (e
->src
, e
->dest
))
3945 force_nonfallthru (e
);
3948 /* Ensure goto_locus from edges has some instructions with that locus in RTL
3949 when not optimizing. */
3950 if (!optimize
&& !DECL_IGNORED_P (current_function_decl
))
3951 FOR_EACH_BB_FN (bb
, cfun
)
3956 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3957 if (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
3958 && !(e
->flags
& EDGE_ABNORMAL
))
3962 basic_block dest
, nb
;
3965 insn
= BB_END (e
->src
);
3966 end
= PREV_INSN (BB_HEAD (e
->src
));
3968 && (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
3969 insn
= PREV_INSN (insn
);
3971 && INSN_LOCATION (insn
) == e
->goto_locus
)
3973 if (simplejump_p (BB_END (e
->src
))
3974 && !INSN_HAS_LOCATION (BB_END (e
->src
)))
3976 INSN_LOCATION (BB_END (e
->src
)) = e
->goto_locus
;
3980 if (dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3982 /* Non-fallthru edges to the exit block cannot be split. */
3983 if (!(e
->flags
& EDGE_FALLTHRU
))
3988 insn
= BB_HEAD (dest
);
3989 end
= NEXT_INSN (BB_END (dest
));
3990 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
3991 insn
= NEXT_INSN (insn
);
3992 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
3993 && INSN_LOCATION (insn
) == e
->goto_locus
)
3996 nb
= split_edge (e
);
3997 if (!INSN_P (BB_END (nb
)))
3998 BB_END (nb
) = emit_insn_after_noloc (gen_nop (), BB_END (nb
),
4000 INSN_LOCATION (BB_END (nb
)) = e
->goto_locus
;
4002 /* If there are other incoming edges to the destination block
4003 with the same goto locus, redirect them to the new block as
4004 well, this can prevent other such blocks from being created
4005 in subsequent iterations of the loop. */
4006 for (ei2
= ei_start (dest
->preds
); (e2
= ei_safe_edge (ei2
)); )
4007 if (LOCATION_LOCUS (e2
->goto_locus
) != UNKNOWN_LOCATION
4008 && !(e2
->flags
& (EDGE_ABNORMAL
| EDGE_FALLTHRU
))
4009 && e
->goto_locus
== e2
->goto_locus
)
4010 redirect_edge_and_branch (e2
, nb
);
4017 /* Perform sanity checks on the insn chain.
4018 1. Check that next/prev pointers are consistent in both the forward and
4020 2. Count insns in chain, going both directions, and check if equal.
4021 3. Check that get_last_insn () returns the actual end of chain. */
4024 verify_insn_chain (void)
4026 rtx_insn
*x
, *prevx
, *nextx
;
4027 int insn_cnt1
, insn_cnt2
;
4029 for (prevx
= NULL
, insn_cnt1
= 1, x
= get_insns ();
4031 prevx
= x
, insn_cnt1
++, x
= NEXT_INSN (x
))
4032 gcc_assert (PREV_INSN (x
) == prevx
);
4034 gcc_assert (prevx
== get_last_insn ());
4036 for (nextx
= NULL
, insn_cnt2
= 1, x
= get_last_insn ();
4038 nextx
= x
, insn_cnt2
++, x
= PREV_INSN (x
))
4039 gcc_assert (NEXT_INSN (x
) == nextx
);
4041 gcc_assert (insn_cnt1
== insn_cnt2
);
4044 /* If we have assembler epilogues, the block falling through to exit must
4045 be the last one in the reordered chain when we reach final. Ensure
4046 that this condition is met. */
4048 fixup_fallthru_exit_predecessor (void)
4051 basic_block bb
= NULL
;
4053 /* This transformation is not valid before reload, because we might
4054 separate a call from the instruction that copies the return
4056 gcc_assert (reload_completed
);
4058 e
= find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4064 basic_block c
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
4066 /* If the very first block is the one with the fall-through exit
4067 edge, we have to split that block. */
4070 bb
= split_block_after_labels (bb
)->dest
;
4073 BB_FOOTER (bb
) = BB_FOOTER (c
);
4074 BB_FOOTER (c
) = NULL
;
4077 while (c
->aux
!= bb
)
4078 c
= (basic_block
) c
->aux
;
4082 c
= (basic_block
) c
->aux
;
4089 /* In case there are more than one fallthru predecessors of exit, force that
4090 there is only one. */
4093 force_one_exit_fallthru (void)
4095 edge e
, predecessor
= NULL
;
4098 basic_block forwarder
, bb
;
4100 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
4101 if (e
->flags
& EDGE_FALLTHRU
)
4103 if (predecessor
== NULL
)
4115 /* Exit has several fallthru predecessors. Create a forwarder block for
4117 forwarder
= split_edge (predecessor
);
4118 for (ei
= ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4119 (e
= ei_safe_edge (ei
)); )
4121 if (e
->src
== forwarder
4122 || !(e
->flags
& EDGE_FALLTHRU
))
4125 redirect_edge_and_branch_force (e
, forwarder
);
4128 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
4130 FOR_EACH_BB_FN (bb
, cfun
)
4132 if (bb
->aux
== NULL
&& bb
!= forwarder
)
4134 bb
->aux
= forwarder
;
4140 /* Return true in case it is possible to duplicate the basic block BB. */
4143 cfg_layout_can_duplicate_bb_p (const_basic_block bb
)
4145 /* Do not attempt to duplicate tablejumps, as we need to unshare
4146 the dispatch table. This is difficult to do, as the instructions
4147 computing jump destination may be hoisted outside the basic block. */
4148 if (tablejump_p (BB_END (bb
), NULL
, NULL
))
4151 /* Do not duplicate blocks containing insns that can't be copied. */
4152 if (targetm
.cannot_copy_insn_p
)
4154 rtx_insn
*insn
= BB_HEAD (bb
);
4157 if (INSN_P (insn
) && targetm
.cannot_copy_insn_p (insn
))
4159 if (insn
== BB_END (bb
))
4161 insn
= NEXT_INSN (insn
);
4169 duplicate_insn_chain (rtx_insn
*from
, rtx_insn
*to
)
4171 rtx_insn
*insn
, *next
, *copy
;
4174 /* Avoid updating of boundaries of previous basic block. The
4175 note will get removed from insn stream in fixup. */
4176 last
= emit_note (NOTE_INSN_DELETED
);
4178 /* Create copy at the end of INSN chain. The chain will
4179 be reordered later. */
4180 for (insn
= from
; insn
!= NEXT_INSN (to
); insn
= NEXT_INSN (insn
))
4182 switch (GET_CODE (insn
))
4185 /* Don't duplicate label debug insns. */
4186 if (DEBUG_BIND_INSN_P (insn
)
4187 && TREE_CODE (INSN_VAR_LOCATION_DECL (insn
)) == LABEL_DECL
)
4193 copy
= emit_copy_of_insn_after (insn
, get_last_insn ());
4194 if (JUMP_P (insn
) && JUMP_LABEL (insn
) != NULL_RTX
4195 && ANY_RETURN_P (JUMP_LABEL (insn
)))
4196 JUMP_LABEL (copy
) = JUMP_LABEL (insn
);
4197 maybe_copy_prologue_epilogue_insn (insn
, copy
);
4200 case JUMP_TABLE_DATA
:
4201 /* Avoid copying of dispatch tables. We never duplicate
4202 tablejumps, so this can hit only in case the table got
4203 moved far from original jump.
4204 Avoid copying following barrier as well if any
4205 (and debug insns in between). */
4206 for (next
= NEXT_INSN (insn
);
4207 next
!= NEXT_INSN (to
);
4208 next
= NEXT_INSN (next
))
4209 if (!DEBUG_INSN_P (next
))
4211 if (next
!= NEXT_INSN (to
) && BARRIER_P (next
))
4223 switch (NOTE_KIND (insn
))
4225 /* In case prologue is empty and function contain label
4226 in first BB, we may want to copy the block. */
4227 case NOTE_INSN_PROLOGUE_END
:
4229 case NOTE_INSN_DELETED
:
4230 case NOTE_INSN_DELETED_LABEL
:
4231 case NOTE_INSN_DELETED_DEBUG_LABEL
:
4232 /* No problem to strip these. */
4233 case NOTE_INSN_FUNCTION_BEG
:
4234 /* There is always just single entry to function. */
4235 case NOTE_INSN_BASIC_BLOCK
:
4236 /* We should only switch text sections once. */
4237 case NOTE_INSN_SWITCH_TEXT_SECTIONS
:
4240 case NOTE_INSN_EPILOGUE_BEG
:
4241 case NOTE_INSN_UPDATE_SJLJ_CONTEXT
:
4242 emit_note_copy (as_a
<rtx_note
*> (insn
));
4246 /* All other notes should have already been eliminated. */
4254 insn
= NEXT_INSN (last
);
4259 /* Create a duplicate of the basic block BB. */
4262 cfg_layout_duplicate_bb (basic_block bb
, copy_bb_data
*)
4267 insn
= duplicate_insn_chain (BB_HEAD (bb
), BB_END (bb
));
4268 new_bb
= create_basic_block (insn
,
4269 insn
? get_last_insn () : NULL
,
4270 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
);
4272 BB_COPY_PARTITION (new_bb
, bb
);
4275 insn
= BB_HEADER (bb
);
4276 while (NEXT_INSN (insn
))
4277 insn
= NEXT_INSN (insn
);
4278 insn
= duplicate_insn_chain (BB_HEADER (bb
), insn
);
4280 BB_HEADER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4285 insn
= BB_FOOTER (bb
);
4286 while (NEXT_INSN (insn
))
4287 insn
= NEXT_INSN (insn
);
4288 insn
= duplicate_insn_chain (BB_FOOTER (bb
), insn
);
4290 BB_FOOTER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4297 /* Main entry point to this module - initialize the datastructures for
4298 CFG layout changes. It keeps LOOPS up-to-date if not null.
4300 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
4303 cfg_layout_initialize (int flags
)
4308 /* Once bb partitioning is complete, cfg layout mode should not be
4309 re-entered. Entering cfg layout mode may require fixups. As an
4310 example, if edge forwarding performed when optimizing the cfg
4311 layout required moving a block from the hot to the cold
4312 section. This would create an illegal partitioning unless some
4313 manual fixup was performed. */
4314 gcc_assert (!crtl
->bb_reorder_complete
|| !crtl
->has_bb_partition
);
4316 initialize_original_copy_tables ();
4318 cfg_layout_rtl_register_cfg_hooks ();
4320 record_effective_endpoints ();
4322 /* Make sure that the targets of non local gotos are marked. */
4323 for (x
= nonlocal_goto_handler_labels
; x
; x
= x
->next ())
4325 bb
= BLOCK_FOR_INSN (x
->insn ());
4326 bb
->flags
|= BB_NON_LOCAL_GOTO_TARGET
;
4329 cleanup_cfg (CLEANUP_CFGLAYOUT
| flags
);
4332 /* Splits superblocks. */
4334 break_superblocks (void)
4339 auto_sbitmap
superblocks (last_basic_block_for_fn (cfun
));
4340 bitmap_clear (superblocks
);
4342 FOR_EACH_BB_FN (bb
, cfun
)
4343 if (bb
->flags
& BB_SUPERBLOCK
)
4345 bb
->flags
&= ~BB_SUPERBLOCK
;
4346 bitmap_set_bit (superblocks
, bb
->index
);
4352 rebuild_jump_labels (get_insns ());
4353 find_many_sub_basic_blocks (superblocks
);
4357 /* Finalize the changes: reorder insn list according to the sequence specified
4358 by aux pointers, enter compensation code, rebuild scope forest. */
4361 cfg_layout_finalize (void)
4363 free_dominance_info (CDI_DOMINATORS
);
4364 force_one_exit_fallthru ();
4365 rtl_register_cfg_hooks ();
4366 if (reload_completed
&& !targetm
.have_epilogue ())
4367 fixup_fallthru_exit_predecessor ();
4368 fixup_reorder_chain ();
4370 rebuild_jump_labels (get_insns ());
4371 delete_dead_jumptables ();
4374 verify_insn_chain ();
4375 checking_verify_flow_info ();
4379 /* Same as split_block but update cfg_layout structures. */
4382 cfg_layout_split_block (basic_block bb
, void *insnp
)
4384 rtx insn
= (rtx
) insnp
;
4385 basic_block new_bb
= rtl_split_block (bb
, insn
);
4387 BB_FOOTER (new_bb
) = BB_FOOTER (bb
);
4388 BB_FOOTER (bb
) = NULL
;
4393 /* Redirect Edge to DEST. */
4395 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
4397 basic_block src
= e
->src
;
4400 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4403 if (e
->dest
== dest
)
4406 if (e
->flags
& EDGE_CROSSING
4407 && BB_PARTITION (e
->src
) == BB_PARTITION (dest
)
4408 && simplejump_p (BB_END (src
)))
4412 "Removing crossing jump while redirecting edge form %i to %i\n",
4413 e
->src
->index
, dest
->index
);
4414 delete_insn (BB_END (src
));
4415 remove_barriers_from_footer (src
);
4416 e
->flags
|= EDGE_FALLTHRU
;
4419 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4420 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
4422 df_set_bb_dirty (src
);
4426 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4427 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
4430 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
4431 e
->src
->index
, dest
->index
);
4433 df_set_bb_dirty (e
->src
);
4434 redirect_edge_succ (e
, dest
);
4438 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
4439 in the case the basic block appears to be in sequence. Avoid this
4442 if (e
->flags
& EDGE_FALLTHRU
)
4444 /* Redirect any branch edges unified with the fallthru one. */
4445 if (JUMP_P (BB_END (src
))
4446 && label_is_jump_target_p (BB_HEAD (e
->dest
),
4452 fprintf (dump_file
, "Fallthru edge unified with branch "
4453 "%i->%i redirected to %i\n",
4454 e
->src
->index
, e
->dest
->index
, dest
->index
);
4455 e
->flags
&= ~EDGE_FALLTHRU
;
4456 redirected
= redirect_branch_edge (e
, dest
);
4457 gcc_assert (redirected
);
4458 redirected
->flags
|= EDGE_FALLTHRU
;
4459 df_set_bb_dirty (redirected
->src
);
4462 /* In case we are redirecting fallthru edge to the branch edge
4463 of conditional jump, remove it. */
4464 if (EDGE_COUNT (src
->succs
) == 2)
4466 /* Find the edge that is different from E. */
4467 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
4470 && any_condjump_p (BB_END (src
))
4471 && onlyjump_p (BB_END (src
)))
4472 delete_insn (BB_END (src
));
4475 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
4476 e
->src
->index
, e
->dest
->index
, dest
->index
);
4477 ret
= redirect_edge_succ_nodup (e
, dest
);
4480 ret
= redirect_branch_edge (e
, dest
);
4485 fixup_partition_crossing (ret
);
4486 /* We don't want simplejumps in the insn stream during cfglayout. */
4487 gcc_assert (!simplejump_p (BB_END (src
)) || CROSSING_JUMP_P (BB_END (src
)));
4489 df_set_bb_dirty (src
);
4493 /* Simple wrapper as we always can redirect fallthru edges. */
4495 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4497 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
4499 gcc_assert (redirected
);
4503 /* Same as delete_basic_block but update cfg_layout structures. */
4506 cfg_layout_delete_block (basic_block bb
)
4508 rtx_insn
*insn
, *next
, *prev
= PREV_INSN (BB_HEAD (bb
)), *remaints
;
4513 next
= BB_HEAD (bb
);
4515 SET_NEXT_INSN (prev
) = BB_HEADER (bb
);
4517 set_first_insn (BB_HEADER (bb
));
4518 SET_PREV_INSN (BB_HEADER (bb
)) = prev
;
4519 insn
= BB_HEADER (bb
);
4520 while (NEXT_INSN (insn
))
4521 insn
= NEXT_INSN (insn
);
4522 SET_NEXT_INSN (insn
) = next
;
4523 SET_PREV_INSN (next
) = insn
;
4525 next
= NEXT_INSN (BB_END (bb
));
4528 insn
= BB_FOOTER (bb
);
4531 if (BARRIER_P (insn
))
4533 if (PREV_INSN (insn
))
4534 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
4536 BB_FOOTER (bb
) = NEXT_INSN (insn
);
4537 if (NEXT_INSN (insn
))
4538 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
4542 insn
= NEXT_INSN (insn
);
4547 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
4548 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
4549 while (NEXT_INSN (insn
))
4550 insn
= NEXT_INSN (insn
);
4551 SET_NEXT_INSN (insn
) = next
;
4553 SET_PREV_INSN (next
) = insn
;
4555 set_last_insn (insn
);
4558 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4559 to
= &BB_HEADER (bb
->next_bb
);
4561 to
= &cfg_layout_function_footer
;
4563 rtl_delete_block (bb
);
4566 prev
= NEXT_INSN (prev
);
4568 prev
= get_insns ();
4570 next
= PREV_INSN (next
);
4572 next
= get_last_insn ();
4574 if (next
&& NEXT_INSN (next
) != prev
)
4576 remaints
= unlink_insn_chain (prev
, next
);
4578 while (NEXT_INSN (insn
))
4579 insn
= NEXT_INSN (insn
);
4580 SET_NEXT_INSN (insn
) = *to
;
4582 SET_PREV_INSN (*to
) = insn
;
4587 /* Return true when blocks A and B can be safely merged. */
4590 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
4592 /* If we are partitioning hot/cold basic blocks, we don't want to
4593 mess up unconditional or indirect jumps that cross between hot
4596 Basic block partitioning may result in some jumps that appear to
4597 be optimizable (or blocks that appear to be mergeable), but which really
4598 must be left untouched (they are required to make it safely across
4599 partition boundaries). See the comments at the top of
4600 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4602 if (BB_PARTITION (a
) != BB_PARTITION (b
))
4605 /* Protect the loop latches. */
4606 if (current_loops
&& b
->loop_father
->latch
== b
)
4609 /* If we would end up moving B's instructions, make sure it doesn't fall
4610 through into the exit block, since we cannot recover from a fallthrough
4611 edge into the exit block occurring in the middle of a function. */
4612 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4614 edge e
= find_fallthru_edge (b
->succs
);
4615 if (e
&& e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4619 /* There must be exactly one edge in between the blocks. */
4620 return (single_succ_p (a
)
4621 && single_succ (a
) == b
4622 && single_pred_p (b
) == 1
4624 /* Must be simple edge. */
4625 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
4626 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4627 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
4628 /* If the jump insn has side effects, we can't kill the edge.
4629 When not optimizing, try_redirect_by_replacing_jump will
4630 not allow us to redirect an edge by replacing a table jump. */
4631 && (!JUMP_P (BB_END (a
))
4632 || ((!optimize
|| reload_completed
)
4633 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
4636 /* Merge block A and B. The blocks must be mergeable. */
4639 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
4641 /* If B is a forwarder block whose outgoing edge has no location, we'll
4642 propagate the locus of the edge between A and B onto it. */
4643 const bool forward_edge_locus
4644 = (b
->flags
& BB_FORWARDER_BLOCK
) != 0
4645 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
;
4648 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
4651 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
4654 /* If there was a CODE_LABEL beginning B, delete it. */
4655 if (LABEL_P (BB_HEAD (b
)))
4657 delete_insn (BB_HEAD (b
));
4660 /* We should have fallthru edge in a, or we can do dummy redirection to get
4662 if (JUMP_P (BB_END (a
)))
4663 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
4664 gcc_assert (!JUMP_P (BB_END (a
)));
4666 /* If not optimizing, preserve the locus of the single edge between
4667 blocks A and B if necessary by emitting a nop. */
4669 && !forward_edge_locus
4670 && !DECL_IGNORED_P (current_function_decl
))
4671 emit_nop_for_unique_locus_between (a
, b
);
4673 /* Move things from b->footer after a->footer. */
4677 BB_FOOTER (a
) = BB_FOOTER (b
);
4680 rtx_insn
*last
= BB_FOOTER (a
);
4682 while (NEXT_INSN (last
))
4683 last
= NEXT_INSN (last
);
4684 SET_NEXT_INSN (last
) = BB_FOOTER (b
);
4685 SET_PREV_INSN (BB_FOOTER (b
)) = last
;
4687 BB_FOOTER (b
) = NULL
;
4690 /* Move things from b->header before a->footer.
4691 Note that this may include dead tablejump data, but we don't clean
4692 those up until we go out of cfglayout mode. */
4695 if (! BB_FOOTER (a
))
4696 BB_FOOTER (a
) = BB_HEADER (b
);
4699 rtx_insn
*last
= BB_HEADER (b
);
4701 while (NEXT_INSN (last
))
4702 last
= NEXT_INSN (last
);
4703 SET_NEXT_INSN (last
) = BB_FOOTER (a
);
4704 SET_PREV_INSN (BB_FOOTER (a
)) = last
;
4705 BB_FOOTER (a
) = BB_HEADER (b
);
4707 BB_HEADER (b
) = NULL
;
4710 /* In the case basic blocks are not adjacent, move them around. */
4711 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4713 insn
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
4715 emit_insn_after_noloc (insn
, BB_END (a
), a
);
4717 /* Otherwise just re-associate the instructions. */
4721 BB_END (a
) = BB_END (b
);
4724 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4725 We need to explicitly call. */
4726 update_bb_for_insn_chain (insn
, BB_END (b
), a
);
4728 /* Skip possible DELETED_LABEL insn. */
4729 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
4730 insn
= NEXT_INSN (insn
);
4731 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
4732 BB_HEAD (b
) = BB_END (b
) = NULL
;
4735 df_bb_delete (b
->index
);
4737 if (forward_edge_locus
)
4738 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
4741 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
4747 cfg_layout_split_edge (edge e
)
4749 basic_block new_bb
=
4750 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4751 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
4754 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4755 BB_COPY_PARTITION (new_bb
, e
->src
);
4757 BB_COPY_PARTITION (new_bb
, e
->dest
);
4758 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
4759 redirect_edge_and_branch_force (e
, new_bb
);
4764 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4767 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
4771 /* Return true if BB contains only labels or non-executable
4775 rtl_block_empty_p (basic_block bb
)
4779 if (bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4780 || bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4783 FOR_BB_INSNS (bb
, insn
)
4784 if (NONDEBUG_INSN_P (insn
) && !any_uncondjump_p (insn
))
4790 /* Split a basic block if it ends with a conditional branch and if
4791 the other part of the block is not empty. */
4794 rtl_split_block_before_cond_jump (basic_block bb
)
4797 rtx_insn
*split_point
= NULL
;
4798 rtx_insn
*last
= NULL
;
4799 bool found_code
= false;
4801 FOR_BB_INSNS (bb
, insn
)
4803 if (any_condjump_p (insn
))
4805 else if (NONDEBUG_INSN_P (insn
))
4810 /* Did not find everything. */
4811 if (found_code
&& split_point
)
4812 return split_block (bb
, split_point
)->dest
;
4817 /* Return 1 if BB ends with a call, possibly followed by some
4818 instructions that must stay with the call, 0 otherwise. */
4821 rtl_block_ends_with_call_p (basic_block bb
)
4823 rtx_insn
*insn
= BB_END (bb
);
4825 while (!CALL_P (insn
)
4826 && insn
!= BB_HEAD (bb
)
4827 && (keep_with_call_p (insn
)
4829 || DEBUG_INSN_P (insn
)))
4830 insn
= PREV_INSN (insn
);
4831 return (CALL_P (insn
));
4834 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4837 rtl_block_ends_with_condjump_p (const_basic_block bb
)
4839 return any_condjump_p (BB_END (bb
));
4842 /* Return true if we need to add fake edge to exit.
4843 Helper function for rtl_flow_call_edges_add. */
4846 need_fake_edge_p (const rtx_insn
*insn
)
4852 && !SIBLING_CALL_P (insn
)
4853 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
4854 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
4857 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
4858 && MEM_VOLATILE_P (PATTERN (insn
)))
4859 || (GET_CODE (PATTERN (insn
)) == PARALLEL
4860 && asm_noperands (insn
) != -1
4861 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
4862 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
4865 /* Add fake edges to the function exit for any non constant and non noreturn
4866 calls, volatile inline assembly in the bitmap of blocks specified by
4867 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4870 The goal is to expose cases in which entering a basic block does not imply
4871 that all subsequent instructions must be executed. */
4874 rtl_flow_call_edges_add (sbitmap blocks
)
4877 int blocks_split
= 0;
4878 int last_bb
= last_basic_block_for_fn (cfun
);
4879 bool check_last_block
= false;
4881 if (n_basic_blocks_for_fn (cfun
) == NUM_FIXED_BLOCKS
)
4885 check_last_block
= true;
4887 check_last_block
= bitmap_bit_p (blocks
,
4888 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
->index
);
4890 /* In the last basic block, before epilogue generation, there will be
4891 a fallthru edge to EXIT. Special care is required if the last insn
4892 of the last basic block is a call because make_edge folds duplicate
4893 edges, which would result in the fallthru edge also being marked
4894 fake, which would result in the fallthru edge being removed by
4895 remove_fake_edges, which would result in an invalid CFG.
4897 Moreover, we can't elide the outgoing fake edge, since the block
4898 profiler needs to take this into account in order to solve the minimal
4899 spanning tree in the case that the call doesn't return.
4901 Handle this by adding a dummy instruction in a new last basic block. */
4902 if (check_last_block
)
4904 basic_block bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
;
4905 rtx_insn
*insn
= BB_END (bb
);
4907 /* Back up past insns that must be kept in the same block as a call. */
4908 while (insn
!= BB_HEAD (bb
)
4909 && keep_with_call_p (insn
))
4910 insn
= PREV_INSN (insn
);
4912 if (need_fake_edge_p (insn
))
4916 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4919 insert_insn_on_edge (gen_use (const0_rtx
), e
);
4920 commit_edge_insertions ();
4925 /* Now add fake edges to the function exit for any non constant
4926 calls since there is no way that we can determine if they will
4929 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
4931 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
4933 rtx_insn
*prev_insn
;
4938 if (blocks
&& !bitmap_bit_p (blocks
, i
))
4941 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
4943 prev_insn
= PREV_INSN (insn
);
4944 if (need_fake_edge_p (insn
))
4947 rtx_insn
*split_at_insn
= insn
;
4949 /* Don't split the block between a call and an insn that should
4950 remain in the same block as the call. */
4952 while (split_at_insn
!= BB_END (bb
)
4953 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
4954 split_at_insn
= NEXT_INSN (split_at_insn
);
4956 /* The handling above of the final block before the epilogue
4957 should be enough to verify that there is no edge to the exit
4958 block in CFG already. Calling make_edge in such case would
4959 cause us to mark that edge as fake and remove it later. */
4961 if (flag_checking
&& split_at_insn
== BB_END (bb
))
4963 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4964 gcc_assert (e
== NULL
);
4967 /* Note that the following may create a new basic block
4968 and renumber the existing basic blocks. */
4969 if (split_at_insn
!= BB_END (bb
))
4971 e
= split_block (bb
, split_at_insn
);
4976 edge ne
= make_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), EDGE_FAKE
);
4977 ne
->probability
= profile_probability::guessed_never ();
4980 if (insn
== BB_HEAD (bb
))
4986 verify_flow_info ();
4988 return blocks_split
;
4991 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4992 the conditional branch target, SECOND_HEAD should be the fall-thru
4993 there is no need to handle this here the loop versioning code handles
4994 this. the reason for SECON_HEAD is that it is needed for condition
4995 in trees, and this should be of the same type since it is a hook. */
4997 rtl_lv_add_condition_to_bb (basic_block first_head
,
4998 basic_block second_head ATTRIBUTE_UNUSED
,
4999 basic_block cond_bb
, void *comp_rtx
)
5001 rtx_code_label
*label
;
5002 rtx_insn
*seq
, *jump
;
5003 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
5004 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
5005 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
5009 label
= block_label (first_head
);
5010 mode
= GET_MODE (op0
);
5011 if (mode
== VOIDmode
)
5012 mode
= GET_MODE (op1
);
5015 op0
= force_operand (op0
, NULL_RTX
);
5016 op1
= force_operand (op1
, NULL_RTX
);
5017 do_compare_rtx_and_jump (op0
, op1
, comp
, 0, mode
, NULL_RTX
, NULL
, label
,
5018 profile_probability::uninitialized ());
5019 jump
= get_last_insn ();
5020 JUMP_LABEL (jump
) = label
;
5021 LABEL_NUSES (label
)++;
5025 /* Add the new cond, in the new head. */
5026 emit_insn_after (seq
, BB_END (cond_bb
));
5030 /* Given a block B with unconditional branch at its end, get the
5031 store the return the branch edge and the fall-thru edge in
5032 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
5034 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
5035 edge
*fallthru_edge
)
5037 edge e
= EDGE_SUCC (b
, 0);
5039 if (e
->flags
& EDGE_FALLTHRU
)
5042 *branch_edge
= EDGE_SUCC (b
, 1);
5047 *fallthru_edge
= EDGE_SUCC (b
, 1);
5052 init_rtl_bb_info (basic_block bb
)
5054 gcc_assert (!bb
->il
.x
.rtl
);
5055 bb
->il
.x
.head_
= NULL
;
5056 bb
->il
.x
.rtl
= ggc_cleared_alloc
<rtl_bb_info
> ();
5059 /* Returns true if it is possible to remove edge E by redirecting
5060 it to the destination of the other edge from E->src. */
5063 rtl_can_remove_branch_p (const_edge e
)
5065 const_basic_block src
= e
->src
;
5066 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
5067 const rtx_insn
*insn
= BB_END (src
);
5070 /* The conditions are taken from try_redirect_by_replacing_jump. */
5071 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
5074 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
5077 if (BB_PARTITION (src
) != BB_PARTITION (target
))
5080 if (!onlyjump_p (insn
)
5081 || tablejump_p (insn
, NULL
, NULL
))
5084 set
= single_set (insn
);
5085 if (!set
|| side_effects_p (set
))
5092 rtl_duplicate_bb (basic_block bb
, copy_bb_data
*id
)
5094 bb
= cfg_layout_duplicate_bb (bb
, id
);
5099 /* Do book-keeping of basic block BB for the profile consistency checker.
5100 Store the counting in RECORD. */
5102 rtl_account_profile_record (basic_block bb
, struct profile_record
*record
)
5105 FOR_BB_INSNS (bb
, insn
)
5108 record
->size
+= insn_cost (insn
, false);
5109 if (bb
->count
.initialized_p ())
5111 += insn_cost (insn
, true) * bb
->count
.to_gcov_type ();
5112 else if (profile_status_for_fn (cfun
) == PROFILE_GUESSED
)
5114 += insn_cost (insn
, true) * bb
->count
.to_frequency (cfun
);
5118 /* Implementation of CFG manipulation for linearized RTL. */
5119 struct cfg_hooks rtl_cfg_hooks
= {
5121 rtl_verify_flow_info
,
5123 rtl_dump_bb_for_graph
,
5124 rtl_create_basic_block
,
5125 rtl_redirect_edge_and_branch
,
5126 rtl_redirect_edge_and_branch_force
,
5127 rtl_can_remove_branch_p
,
5130 rtl_move_block_after
,
5131 rtl_can_merge_blocks
, /* can_merge_blocks_p */
5135 cfg_layout_can_duplicate_bb_p
,
5138 rtl_make_forwarder_block
,
5139 rtl_tidy_fallthru_edge
,
5140 rtl_force_nonfallthru
,
5141 rtl_block_ends_with_call_p
,
5142 rtl_block_ends_with_condjump_p
,
5143 rtl_flow_call_edges_add
,
5144 NULL
, /* execute_on_growing_pred */
5145 NULL
, /* execute_on_shrinking_pred */
5146 NULL
, /* duplicate loop for trees */
5147 NULL
, /* lv_add_condition_to_bb */
5148 NULL
, /* lv_adjust_loop_header_phi*/
5149 NULL
, /* extract_cond_bb_edges */
5150 NULL
, /* flush_pending_stmts */
5151 rtl_block_empty_p
, /* block_empty_p */
5152 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5153 rtl_account_profile_record
,
5156 /* Implementation of CFG manipulation for cfg layout RTL, where
5157 basic block connected via fallthru edges does not have to be adjacent.
5158 This representation will hopefully become the default one in future
5159 version of the compiler. */
5161 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
5163 rtl_verify_flow_info_1
,
5165 rtl_dump_bb_for_graph
,
5166 cfg_layout_create_basic_block
,
5167 cfg_layout_redirect_edge_and_branch
,
5168 cfg_layout_redirect_edge_and_branch_force
,
5169 rtl_can_remove_branch_p
,
5170 cfg_layout_delete_block
,
5171 cfg_layout_split_block
,
5172 rtl_move_block_after
,
5173 cfg_layout_can_merge_blocks_p
,
5174 cfg_layout_merge_blocks
,
5177 cfg_layout_can_duplicate_bb_p
,
5178 cfg_layout_duplicate_bb
,
5179 cfg_layout_split_edge
,
5180 rtl_make_forwarder_block
,
5181 NULL
, /* tidy_fallthru_edge */
5182 rtl_force_nonfallthru
,
5183 rtl_block_ends_with_call_p
,
5184 rtl_block_ends_with_condjump_p
,
5185 rtl_flow_call_edges_add
,
5186 NULL
, /* execute_on_growing_pred */
5187 NULL
, /* execute_on_shrinking_pred */
5188 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5189 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5190 NULL
, /* lv_adjust_loop_header_phi*/
5191 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
5192 NULL
, /* flush_pending_stmts */
5193 rtl_block_empty_p
, /* block_empty_p */
5194 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5195 rtl_account_profile_record
,
5198 #include "gt-cfgrtl.h"
5201 # pragma GCC diagnostic pop