1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
49 /* This file contains functions for building the Control Flow Graph (CFG)
50 for a function tree. */
52 /* Local declarations. */
54 /* Initial capacity for the basic block array. */
55 static const int initial_cfg_capacity
= 20;
57 /* Mapping of labels to their associated blocks. This can greatly speed up
58 building of the CFG in code with lots of gotos. */
59 static GTY(()) varray_type label_to_block_map
;
61 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
62 which use a particular edge. The CASE_LABEL_EXPRs are chained together
63 via their TREE_CHAIN field, which we clear after we're done with the
64 hash table to prevent problems with duplication of SWITCH_EXPRs.
66 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
67 update the case vector in response to edge redirections.
69 Right now this table is set up and torn down at key points in the
70 compilation process. It would be nice if we could make the table
71 more persistent. The key is getting notification of changes to
72 the CFG (particularly edge removal, creation and redirection). */
74 struct edge_to_cases_elt
76 /* The edge itself. Necessary for hashing and equality tests. */
79 /* The case labels associated with this edge. We link these up via
80 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
81 when we destroy the hash table. This prevents problems when copying
86 static htab_t edge_to_cases
;
91 long num_merged_labels
;
94 static struct cfg_stats_d cfg_stats
;
96 /* Nonzero if we found a computed goto while building basic blocks. */
97 static bool found_computed_goto
;
99 /* Basic blocks and flowgraphs. */
100 static basic_block
create_bb (void *, void *, basic_block
);
101 static void create_block_annotation (basic_block
);
102 static void free_blocks_annotations (void);
103 static void clear_blocks_annotations (void);
104 static void make_blocks (tree
);
105 static void factor_computed_gotos (void);
108 static void make_edges (void);
109 static void make_ctrl_stmt_edges (basic_block
);
110 static void make_exit_edges (basic_block
);
111 static void make_cond_expr_edges (basic_block
);
112 static void make_switch_expr_edges (basic_block
);
113 static void make_goto_expr_edges (basic_block
);
114 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
115 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
116 static void split_critical_edges (void);
117 static bool remove_fallthru_edge (VEC(edge
) *);
119 /* Various helpers. */
120 static inline bool stmt_starts_bb_p (tree
, tree
);
121 static int tree_verify_flow_info (void);
122 static void tree_make_forwarder_block (edge
);
123 static bool tree_forwarder_block_p (basic_block
, bool);
124 static void tree_cfg2vcg (FILE *);
126 /* Flowgraph optimization and cleanup. */
127 static void tree_merge_blocks (basic_block
, basic_block
);
128 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
129 static void remove_bb (basic_block
);
130 static bool cleanup_control_flow (void);
131 static bool cleanup_control_expr_graph (basic_block
, block_stmt_iterator
);
132 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
133 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
134 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
135 static tree
find_case_label_for_value (tree
, tree
);
136 static bool phi_alternatives_equal (basic_block
, edge
, edge
);
137 static bool cleanup_forwarder_blocks (void);
140 /*---------------------------------------------------------------------------
142 ---------------------------------------------------------------------------*/
144 /* Entry point to the CFG builder for trees. TP points to the list of
145 statements to be added to the flowgraph. */
148 build_tree_cfg (tree
*tp
)
150 /* Register specific tree functions. */
151 tree_register_cfg_hooks ();
153 /* Initialize rbi_pool. */
156 /* Initialize the basic block array. */
158 profile_status
= PROFILE_ABSENT
;
160 last_basic_block
= 0;
161 VARRAY_BB_INIT (basic_block_info
, initial_cfg_capacity
, "basic_block_info");
162 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
164 /* Build a mapping of labels to their associated blocks. */
165 VARRAY_BB_INIT (label_to_block_map
, initial_cfg_capacity
,
166 "label to block map");
168 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
169 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
171 found_computed_goto
= 0;
174 /* Computed gotos are hell to deal with, especially if there are
175 lots of them with a large number of destinations. So we factor
176 them to a common computed goto location before we build the
177 edge list. After we convert back to normal form, we will un-factor
178 the computed gotos since factoring introduces an unwanted jump. */
179 if (found_computed_goto
)
180 factor_computed_gotos ();
182 /* Make sure there is always at least one block, even if it's empty. */
183 if (n_basic_blocks
== 0)
184 create_empty_bb (ENTRY_BLOCK_PTR
);
186 create_block_annotation (ENTRY_BLOCK_PTR
);
187 create_block_annotation (EXIT_BLOCK_PTR
);
189 /* Adjust the size of the array. */
190 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
192 /* To speed up statement iterator walks, we first purge dead labels. */
193 cleanup_dead_labels ();
195 /* Group case nodes to reduce the number of edges.
196 We do this after cleaning up dead labels because otherwise we miss
197 a lot of obvious case merging opportunities. */
198 group_case_labels ();
200 /* Create the edges of the flowgraph. */
203 /* Debugging dumps. */
205 /* Write the flowgraph to a VCG file. */
207 int local_dump_flags
;
208 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
211 tree_cfg2vcg (dump_file
);
212 dump_end (TDI_vcg
, dump_file
);
216 /* Dump a textual representation of the flowgraph. */
218 dump_tree_cfg (dump_file
, dump_flags
);
222 execute_build_cfg (void)
224 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
227 struct tree_opt_pass pass_build_cfg
=
231 execute_build_cfg
, /* execute */
234 0, /* static_pass_number */
235 TV_TREE_CFG
, /* tv_id */
236 PROP_gimple_leh
, /* properties_required */
237 PROP_cfg
, /* properties_provided */
238 0, /* properties_destroyed */
239 0, /* todo_flags_start */
240 TODO_verify_stmts
, /* todo_flags_finish */
244 /* Search the CFG for any computed gotos. If found, factor them to a
245 common computed goto site. Also record the location of that site so
246 that we can un-factor the gotos after we have converted back to
250 factor_computed_gotos (void)
253 tree factored_label_decl
= NULL
;
255 tree factored_computed_goto_label
= NULL
;
256 tree factored_computed_goto
= NULL
;
258 /* We know there are one or more computed gotos in this function.
259 Examine the last statement in each basic block to see if the block
260 ends with a computed goto. */
264 block_stmt_iterator bsi
= bsi_last (bb
);
269 last
= bsi_stmt (bsi
);
271 /* Ignore the computed goto we create when we factor the original
273 if (last
== factored_computed_goto
)
276 /* If the last statement is a computed goto, factor it. */
277 if (computed_goto_p (last
))
281 /* The first time we find a computed goto we need to create
282 the factored goto block and the variable each original
283 computed goto will use for their goto destination. */
284 if (! factored_computed_goto
)
286 basic_block new_bb
= create_empty_bb (bb
);
287 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
289 /* Create the destination of the factored goto. Each original
290 computed goto will put its desired destination into this
291 variable and jump to the label we create immediately
293 var
= create_tmp_var (ptr_type_node
, "gotovar");
295 /* Build a label for the new block which will contain the
296 factored computed goto. */
297 factored_label_decl
= create_artificial_label ();
298 factored_computed_goto_label
299 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
300 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
303 /* Build our new computed goto. */
304 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
305 bsi_insert_after (&new_bsi
, factored_computed_goto
,
309 /* Copy the original computed goto's destination into VAR. */
310 assignment
= build (MODIFY_EXPR
, ptr_type_node
,
311 var
, GOTO_DESTINATION (last
));
312 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
314 /* And re-vector the computed goto to the new destination. */
315 GOTO_DESTINATION (last
) = factored_label_decl
;
321 /* Create annotations for a single basic block. */
324 create_block_annotation (basic_block bb
)
326 /* Verify that the tree_annotations field is clear. */
327 gcc_assert (!bb
->tree_annotations
);
328 bb
->tree_annotations
= ggc_alloc_cleared (sizeof (struct bb_ann_d
));
332 /* Free the annotations for all the basic blocks. */
334 static void free_blocks_annotations (void)
336 clear_blocks_annotations ();
340 /* Clear the annotations for all the basic blocks. */
343 clear_blocks_annotations (void)
347 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
348 bb
->tree_annotations
= NULL
;
352 /* Build a flowgraph for the statement_list STMT_LIST. */
355 make_blocks (tree stmt_list
)
357 tree_stmt_iterator i
= tsi_start (stmt_list
);
359 bool start_new_block
= true;
360 bool first_stmt_of_list
= true;
361 basic_block bb
= ENTRY_BLOCK_PTR
;
363 while (!tsi_end_p (i
))
370 /* If the statement starts a new basic block or if we have determined
371 in a previous pass that we need to create a new block for STMT, do
373 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
375 if (!first_stmt_of_list
)
376 stmt_list
= tsi_split_statement_list_before (&i
);
377 bb
= create_basic_block (stmt_list
, NULL
, bb
);
378 start_new_block
= false;
381 /* Now add STMT to BB and create the subgraphs for special statement
383 set_bb_for_stmt (stmt
, bb
);
385 if (computed_goto_p (stmt
))
386 found_computed_goto
= true;
388 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
390 if (stmt_ends_bb_p (stmt
))
391 start_new_block
= true;
394 first_stmt_of_list
= false;
399 /* Create and return a new empty basic block after bb AFTER. */
402 create_bb (void *h
, void *e
, basic_block after
)
408 /* Create and initialize a new basic block. Since alloc_block uses
409 ggc_alloc_cleared to allocate a basic block, we do not have to
410 clear the newly allocated basic block here. */
413 bb
->index
= last_basic_block
;
415 bb
->stmt_list
= h
? h
: alloc_stmt_list ();
417 /* Add the new block to the linked list of blocks. */
418 link_block (bb
, after
);
420 /* Grow the basic block array if needed. */
421 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
423 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
424 VARRAY_GROW (basic_block_info
, new_size
);
427 /* Add the newly created block to the array. */
428 BASIC_BLOCK (last_basic_block
) = bb
;
430 create_block_annotation (bb
);
435 initialize_bb_rbi (bb
);
440 /*---------------------------------------------------------------------------
442 ---------------------------------------------------------------------------*/
444 /* Fold COND_EXPR_COND of each COND_EXPR. */
447 fold_cond_expr_cond (void)
453 tree stmt
= last_stmt (bb
);
456 && TREE_CODE (stmt
) == COND_EXPR
)
458 tree cond
= fold (COND_EXPR_COND (stmt
));
459 if (integer_zerop (cond
))
460 COND_EXPR_COND (stmt
) = integer_zero_node
;
461 else if (integer_onep (cond
))
462 COND_EXPR_COND (stmt
) = integer_one_node
;
467 /* Join all the blocks in the flowgraph. */
474 /* Create an edge from entry to the first block with executable
476 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (0), EDGE_FALLTHRU
);
478 /* Traverse the basic block array placing edges. */
481 tree first
= first_stmt (bb
);
482 tree last
= last_stmt (bb
);
486 /* Edges for statements that always alter flow control. */
487 if (is_ctrl_stmt (last
))
488 make_ctrl_stmt_edges (bb
);
490 /* Edges for statements that sometimes alter flow control. */
491 if (is_ctrl_altering_stmt (last
))
492 make_exit_edges (bb
);
495 /* Finally, if no edges were created above, this is a regular
496 basic block that only needs a fallthru edge. */
497 if (EDGE_COUNT (bb
->succs
) == 0)
498 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
501 /* We do not care about fake edges, so remove any that the CFG
502 builder inserted for completeness. */
503 remove_fake_exit_edges ();
505 /* Fold COND_EXPR_COND of each COND_EXPR. */
506 fold_cond_expr_cond ();
508 /* Clean up the graph and warn for unreachable code. */
513 /* Create edges for control statement at basic block BB. */
516 make_ctrl_stmt_edges (basic_block bb
)
518 tree last
= last_stmt (bb
);
521 switch (TREE_CODE (last
))
524 make_goto_expr_edges (bb
);
528 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
532 make_cond_expr_edges (bb
);
536 make_switch_expr_edges (bb
);
540 make_eh_edges (last
);
541 /* Yet another NORETURN hack. */
542 if (EDGE_COUNT (bb
->succs
) == 0)
543 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
552 /* Create exit edges for statements in block BB that alter the flow of
553 control. Statements that alter the control flow are 'goto', 'return'
554 and calls to non-returning functions. */
557 make_exit_edges (basic_block bb
)
559 tree last
= last_stmt (bb
), op
;
562 switch (TREE_CODE (last
))
565 /* If this function receives a nonlocal goto, then we need to
566 make edges from this call site to all the nonlocal goto
568 if (TREE_SIDE_EFFECTS (last
)
569 && current_function_has_nonlocal_label
)
570 make_goto_expr_edges (bb
);
572 /* If this statement has reachable exception handlers, then
573 create abnormal edges to them. */
574 make_eh_edges (last
);
576 /* Some calls are known not to return. For such calls we create
579 We really need to revamp how we build edges so that it's not
580 such a bloody pain to avoid creating edges for this case since
581 all we do is remove these edges when we're done building the
583 if (call_expr_flags (last
) & ECF_NORETURN
)
585 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
589 /* Don't forget the fall-thru edge. */
590 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
594 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
595 may have an abnormal edge. Search the RHS for this case and
596 create any required edges. */
597 op
= get_call_expr_in (last
);
598 if (op
&& TREE_SIDE_EFFECTS (op
)
599 && current_function_has_nonlocal_label
)
600 make_goto_expr_edges (bb
);
602 make_eh_edges (last
);
603 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
612 /* Create the edges for a COND_EXPR starting at block BB.
613 At this point, both clauses must contain only simple gotos. */
616 make_cond_expr_edges (basic_block bb
)
618 tree entry
= last_stmt (bb
);
619 basic_block then_bb
, else_bb
;
620 tree then_label
, else_label
;
623 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
625 /* Entry basic blocks for each component. */
626 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
627 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
628 then_bb
= label_to_block (then_label
);
629 else_bb
= label_to_block (else_label
);
631 make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
632 make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
635 /* Hashing routine for EDGE_TO_CASES. */
638 edge_to_cases_hash (const void *p
)
640 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
642 /* Hash on the edge itself (which is a pointer). */
643 return htab_hash_pointer (e
);
646 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
647 for equality is just a pointer comparison. */
650 edge_to_cases_eq (const void *p1
, const void *p2
)
652 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
653 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
658 /* Called for each element in the hash table (P) as we delete the
659 edge to cases hash table.
661 Clear all the TREE_CHAINs to prevent problems with copying of
662 SWITCH_EXPRs and structure sharing rules, then free the hash table
666 edge_to_cases_cleanup (void *p
)
668 struct edge_to_cases_elt
*elt
= p
;
671 for (t
= elt
->case_labels
; t
; t
= next
)
673 next
= TREE_CHAIN (t
);
674 TREE_CHAIN (t
) = NULL
;
679 /* Start recording information mapping edges to case labels. */
682 start_recording_case_labels (void)
684 gcc_assert (edge_to_cases
== NULL
);
686 edge_to_cases
= htab_create (37,
689 edge_to_cases_cleanup
);
692 /* Return nonzero if we are recording information for case labels. */
695 recording_case_labels_p (void)
697 return (edge_to_cases
!= NULL
);
700 /* Stop recording information mapping edges to case labels and
701 remove any information we have recorded. */
703 end_recording_case_labels (void)
705 htab_delete (edge_to_cases
);
706 edge_to_cases
= NULL
;
709 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
712 record_switch_edge (edge e
, tree case_label
)
714 struct edge_to_cases_elt
*elt
;
717 /* Build a hash table element so we can see if E is already
719 elt
= xmalloc (sizeof (struct edge_to_cases_elt
));
721 elt
->case_labels
= case_label
;
723 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
727 /* E was not in the hash table. Install E into the hash table. */
732 /* E was already in the hash table. Free ELT as we do not need it
736 /* Get the entry stored in the hash table. */
737 elt
= (struct edge_to_cases_elt
*) *slot
;
739 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
740 TREE_CHAIN (case_label
) = elt
->case_labels
;
741 elt
->case_labels
= case_label
;
745 /* If we are inside a {start,end}_recording_cases block, then return
746 a chain of CASE_LABEL_EXPRs from T which reference E.
748 Otherwise return NULL. */
751 get_cases_for_edge (edge e
, tree t
)
753 struct edge_to_cases_elt elt
, *elt_p
;
758 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
759 chains available. Return NULL so the caller can detect this case. */
760 if (!recording_case_labels_p ())
765 elt
.case_labels
= NULL
;
766 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
770 elt_p
= (struct edge_to_cases_elt
*)*slot
;
771 return elt_p
->case_labels
;
774 /* If we did not find E in the hash table, then this must be the first
775 time we have been queried for information about E & T. Add all the
776 elements from T to the hash table then perform the query again. */
778 vec
= SWITCH_LABELS (t
);
779 n
= TREE_VEC_LENGTH (vec
);
780 for (i
= 0; i
< n
; i
++)
782 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
783 basic_block label_bb
= label_to_block (lab
);
784 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
789 /* Create the edges for a SWITCH_EXPR starting at block BB.
790 At this point, the switch body has been lowered and the
791 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
794 make_switch_expr_edges (basic_block bb
)
796 tree entry
= last_stmt (bb
);
800 vec
= SWITCH_LABELS (entry
);
801 n
= TREE_VEC_LENGTH (vec
);
803 for (i
= 0; i
< n
; ++i
)
805 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
806 basic_block label_bb
= label_to_block (lab
);
807 make_edge (bb
, label_bb
, 0);
812 /* Return the basic block holding label DEST. */
815 label_to_block (tree dest
)
817 int uid
= LABEL_DECL_UID (dest
);
819 /* We would die hard when faced by an undefined label. Emit a label to
820 the very first basic block. This will hopefully make even the dataflow
821 and undefined variable warnings quite right. */
822 if ((errorcount
|| sorrycount
) && uid
< 0)
824 block_stmt_iterator bsi
= bsi_start (BASIC_BLOCK (0));
827 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
828 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
829 uid
= LABEL_DECL_UID (dest
);
831 return VARRAY_BB (label_to_block_map
, uid
);
835 /* Create edges for a goto statement at block BB. */
838 make_goto_expr_edges (basic_block bb
)
841 basic_block target_bb
;
843 block_stmt_iterator last
= bsi_last (bb
);
845 goto_t
= bsi_stmt (last
);
847 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
848 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
849 from a nonlocal goto. */
850 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
852 dest
= error_mark_node
;
857 dest
= GOTO_DESTINATION (goto_t
);
860 /* A GOTO to a local label creates normal edges. */
861 if (simple_goto_p (goto_t
))
863 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
864 #ifdef USE_MAPPED_LOCATION
865 e
->goto_locus
= EXPR_LOCATION (goto_t
);
867 e
->goto_locus
= EXPR_LOCUS (goto_t
);
873 /* Nothing more to do for nonlocal gotos. */
874 if (TREE_CODE (dest
) == LABEL_DECL
)
877 /* Computed gotos remain. */
880 /* Look for the block starting with the destination label. In the
881 case of a computed goto, make an edge to any label block we find
883 FOR_EACH_BB (target_bb
)
885 block_stmt_iterator bsi
;
887 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
889 tree target
= bsi_stmt (bsi
);
891 if (TREE_CODE (target
) != LABEL_EXPR
)
895 /* Computed GOTOs. Make an edge to every label block that has
896 been marked as a potential target for a computed goto. */
897 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
898 /* Nonlocal GOTO target. Make an edge to every label block
899 that has been marked as a potential target for a nonlocal
901 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
903 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
909 /* Degenerate case of computed goto with no labels. */
910 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
911 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
915 /*---------------------------------------------------------------------------
917 ---------------------------------------------------------------------------*/
919 /* Remove unreachable blocks and other miscellaneous clean up work. */
922 cleanup_tree_cfg (void)
926 timevar_push (TV_TREE_CLEANUP_CFG
);
928 retval
= cleanup_control_flow ();
929 retval
|= delete_unreachable_blocks ();
931 /* cleanup_forwarder_blocks can redirect edges out of SWITCH_EXPRs,
932 which can get expensive. So we want to enable recording of edge
933 to CASE_LABEL_EXPR mappings around the call to
934 cleanup_forwarder_blocks. */
935 start_recording_case_labels ();
936 retval
|= cleanup_forwarder_blocks ();
937 end_recording_case_labels ();
939 #ifdef ENABLE_CHECKING
942 gcc_assert (!cleanup_control_flow ());
943 gcc_assert (!delete_unreachable_blocks ());
944 gcc_assert (!cleanup_forwarder_blocks ());
948 /* Merging the blocks creates no new opportunities for the other
949 optimizations, so do it here. */
950 retval
|= merge_seq_blocks ();
954 #ifdef ENABLE_CHECKING
957 timevar_pop (TV_TREE_CLEANUP_CFG
);
962 /* Cleanup useless labels in basic blocks. This is something we wish
963 to do early because it allows us to group case labels before creating
964 the edges for the CFG, and it speeds up block statement iterators in
966 We only run this pass once, running it more than once is probably not
969 /* A map from basic block index to the leading label of that block. */
970 static tree
*label_for_bb
;
972 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
974 update_eh_label (struct eh_region
*region
)
976 tree old_label
= get_eh_region_tree_label (region
);
980 basic_block bb
= label_to_block (old_label
);
982 /* ??? After optimizing, there may be EH regions with labels
983 that have already been removed from the function body, so
984 there is no basic block for them. */
988 new_label
= label_for_bb
[bb
->index
];
989 set_eh_region_tree_label (region
, new_label
);
993 /* Given LABEL return the first label in the same basic block. */
995 main_block_label (tree label
)
997 basic_block bb
= label_to_block (label
);
999 /* label_to_block possibly inserted undefined label into the chain. */
1000 if (!label_for_bb
[bb
->index
])
1001 label_for_bb
[bb
->index
] = label
;
1002 return label_for_bb
[bb
->index
];
1005 /* Cleanup redundant labels. This is a three-step process:
1006 1) Find the leading label for each block.
1007 2) Redirect all references to labels to the leading labels.
1008 3) Cleanup all useless labels. */
1011 cleanup_dead_labels (void)
1014 label_for_bb
= xcalloc (last_basic_block
, sizeof (tree
));
1016 /* Find a suitable label for each block. We use the first user-defined
1017 label if there is one, or otherwise just the first label we see. */
1020 block_stmt_iterator i
;
1022 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
1024 tree label
, stmt
= bsi_stmt (i
);
1026 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1029 label
= LABEL_EXPR_LABEL (stmt
);
1031 /* If we have not yet seen a label for the current block,
1032 remember this one and see if there are more labels. */
1033 if (! label_for_bb
[bb
->index
])
1035 label_for_bb
[bb
->index
] = label
;
1039 /* If we did see a label for the current block already, but it
1040 is an artificially created label, replace it if the current
1041 label is a user defined label. */
1042 if (! DECL_ARTIFICIAL (label
)
1043 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
1045 label_for_bb
[bb
->index
] = label
;
1051 /* Now redirect all jumps/branches to the selected label.
1052 First do so for each block ending in a control statement. */
1055 tree stmt
= last_stmt (bb
);
1059 switch (TREE_CODE (stmt
))
1063 tree true_branch
, false_branch
;
1065 true_branch
= COND_EXPR_THEN (stmt
);
1066 false_branch
= COND_EXPR_ELSE (stmt
);
1068 GOTO_DESTINATION (true_branch
)
1069 = main_block_label (GOTO_DESTINATION (true_branch
));
1070 GOTO_DESTINATION (false_branch
)
1071 = main_block_label (GOTO_DESTINATION (false_branch
));
1079 tree vec
= SWITCH_LABELS (stmt
);
1080 size_t n
= TREE_VEC_LENGTH (vec
);
1082 /* Replace all destination labels. */
1083 for (i
= 0; i
< n
; ++i
)
1085 tree elt
= TREE_VEC_ELT (vec
, i
);
1086 tree label
= main_block_label (CASE_LABEL (elt
));
1087 CASE_LABEL (elt
) = label
;
1092 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1093 remove them until after we've created the CFG edges. */
1095 if (! computed_goto_p (stmt
))
1097 GOTO_DESTINATION (stmt
)
1098 = main_block_label (GOTO_DESTINATION (stmt
));
1107 for_each_eh_region (update_eh_label
);
1109 /* Finally, purge dead labels. All user-defined labels and labels that
1110 can be the target of non-local gotos are preserved. */
1113 block_stmt_iterator i
;
1114 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1116 if (! label_for_this_bb
)
1119 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1121 tree label
, stmt
= bsi_stmt (i
);
1123 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1126 label
= LABEL_EXPR_LABEL (stmt
);
1128 if (label
== label_for_this_bb
1129 || ! DECL_ARTIFICIAL (label
)
1130 || DECL_NONLOCAL (label
))
1137 free (label_for_bb
);
1140 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1141 and scan the sorted vector of cases. Combine the ones jumping to the
1143 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1146 group_case_labels (void)
1152 tree stmt
= last_stmt (bb
);
1153 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1155 tree labels
= SWITCH_LABELS (stmt
);
1156 int old_size
= TREE_VEC_LENGTH (labels
);
1157 int i
, j
, new_size
= old_size
;
1158 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1161 /* The default label is always the last case in a switch
1162 statement after gimplification. */
1163 default_label
= CASE_LABEL (default_case
);
1165 /* Look for possible opportunities to merge cases.
1166 Ignore the last element of the label vector because it
1167 must be the default case. */
1169 while (i
< old_size
- 1)
1171 tree base_case
, base_label
, base_high
, type
;
1172 base_case
= TREE_VEC_ELT (labels
, i
);
1174 gcc_assert (base_case
);
1175 base_label
= CASE_LABEL (base_case
);
1177 /* Discard cases that have the same destination as the
1179 if (base_label
== default_label
)
1181 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1187 type
= TREE_TYPE (CASE_LOW (base_case
));
1188 base_high
= CASE_HIGH (base_case
) ?
1189 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1191 /* Try to merge case labels. Break out when we reach the end
1192 of the label vector or when we cannot merge the next case
1193 label with the current one. */
1194 while (i
< old_size
- 1)
1196 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1197 tree merge_label
= CASE_LABEL (merge_case
);
1198 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1199 integer_one_node
, 1);
1201 /* Merge the cases if they jump to the same place,
1202 and their ranges are consecutive. */
1203 if (merge_label
== base_label
1204 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1206 base_high
= CASE_HIGH (merge_case
) ?
1207 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1208 CASE_HIGH (base_case
) = base_high
;
1209 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1218 /* Compress the case labels in the label vector, and adjust the
1219 length of the vector. */
1220 for (i
= 0, j
= 0; i
< new_size
; i
++)
1222 while (! TREE_VEC_ELT (labels
, j
))
1224 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1226 TREE_VEC_LENGTH (labels
) = new_size
;
1231 /* Checks whether we can merge block B into block A. */
1234 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1237 block_stmt_iterator bsi
;
1239 if (EDGE_COUNT (a
->succs
) != 1)
1242 if (EDGE_SUCC (a
, 0)->flags
& EDGE_ABNORMAL
)
1245 if (EDGE_SUCC (a
, 0)->dest
!= b
)
1248 if (EDGE_COUNT (b
->preds
) > 1)
1251 if (b
== EXIT_BLOCK_PTR
)
1254 /* If A ends by a statement causing exceptions or something similar, we
1255 cannot merge the blocks. */
1256 stmt
= last_stmt (a
);
1257 if (stmt
&& stmt_ends_bb_p (stmt
))
1260 /* Do not allow a block with only a non-local label to be merged. */
1261 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1262 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1265 /* There may be no phi nodes at the start of b. Most of these degenerate
1266 phi nodes should be cleaned up by kill_redundant_phi_nodes. */
1270 /* Do not remove user labels. */
1271 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1273 stmt
= bsi_stmt (bsi
);
1274 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1276 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1284 /* Merge block B into block A. */
1287 tree_merge_blocks (basic_block a
, basic_block b
)
1289 block_stmt_iterator bsi
;
1290 tree_stmt_iterator last
;
1293 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1295 /* Ensure that B follows A. */
1296 move_block_after (b
, a
);
1298 gcc_assert (EDGE_SUCC (a
, 0)->flags
& EDGE_FALLTHRU
);
1299 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1301 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1302 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1304 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1306 tree label
= bsi_stmt (bsi
);
1309 /* Now that we can thread computed gotos, we might have
1310 a situation where we have a forced label in block B
1311 However, the label at the start of block B might still be
1312 used in other ways (think about the runtime checking for
1313 Fortran assigned gotos). So we can not just delete the
1314 label. Instead we move the label to the start of block A. */
1315 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1317 block_stmt_iterator dest_bsi
= bsi_start (a
);
1318 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1323 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1328 /* Merge the chains. */
1329 last
= tsi_last (a
->stmt_list
);
1330 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1331 b
->stmt_list
= NULL
;
1335 /* Walk the function tree removing unnecessary statements.
1337 * Empty statement nodes are removed
1339 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1341 * Unnecessary COND_EXPRs are removed
1343 * Some unnecessary BIND_EXPRs are removed
1345 Clearly more work could be done. The trick is doing the analysis
1346 and removal fast enough to be a net improvement in compile times.
1348 Note that when we remove a control structure such as a COND_EXPR
1349 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1350 to ensure we eliminate all the useless code. */
1361 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1364 remove_useless_stmts_warn_notreached (tree stmt
)
1366 if (EXPR_HAS_LOCATION (stmt
))
1368 location_t loc
= EXPR_LOCATION (stmt
);
1369 if (LOCATION_LINE (loc
) > 0)
1371 warning ("%Hwill never be executed", &loc
);
1376 switch (TREE_CODE (stmt
))
1378 case STATEMENT_LIST
:
1380 tree_stmt_iterator i
;
1381 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1382 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1388 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1390 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1392 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1396 case TRY_FINALLY_EXPR
:
1397 case TRY_CATCH_EXPR
:
1398 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1400 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1405 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1406 case EH_FILTER_EXPR
:
1407 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1409 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1412 /* Not a live container. */
1420 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1422 tree then_clause
, else_clause
, cond
;
1423 bool save_has_label
, then_has_label
, else_has_label
;
1425 save_has_label
= data
->has_label
;
1426 data
->has_label
= false;
1427 data
->last_goto
= NULL
;
1429 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1431 then_has_label
= data
->has_label
;
1432 data
->has_label
= false;
1433 data
->last_goto
= NULL
;
1435 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1437 else_has_label
= data
->has_label
;
1438 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1440 then_clause
= COND_EXPR_THEN (*stmt_p
);
1441 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1442 cond
= fold (COND_EXPR_COND (*stmt_p
));
1444 /* If neither arm does anything at all, we can remove the whole IF. */
1445 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1447 *stmt_p
= build_empty_stmt ();
1448 data
->repeat
= true;
1451 /* If there are no reachable statements in an arm, then we can
1452 zap the entire conditional. */
1453 else if (integer_nonzerop (cond
) && !else_has_label
)
1455 if (warn_notreached
)
1456 remove_useless_stmts_warn_notreached (else_clause
);
1457 *stmt_p
= then_clause
;
1458 data
->repeat
= true;
1460 else if (integer_zerop (cond
) && !then_has_label
)
1462 if (warn_notreached
)
1463 remove_useless_stmts_warn_notreached (then_clause
);
1464 *stmt_p
= else_clause
;
1465 data
->repeat
= true;
1468 /* Check a couple of simple things on then/else with single stmts. */
1471 tree then_stmt
= expr_only (then_clause
);
1472 tree else_stmt
= expr_only (else_clause
);
1474 /* Notice branches to a common destination. */
1475 if (then_stmt
&& else_stmt
1476 && TREE_CODE (then_stmt
) == GOTO_EXPR
1477 && TREE_CODE (else_stmt
) == GOTO_EXPR
1478 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1480 *stmt_p
= then_stmt
;
1481 data
->repeat
= true;
1484 /* If the THEN/ELSE clause merely assigns a value to a variable or
1485 parameter which is already known to contain that value, then
1486 remove the useless THEN/ELSE clause. */
1487 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1490 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1491 && TREE_OPERAND (else_stmt
, 0) == cond
1492 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1493 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1495 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1496 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1497 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1498 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1500 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1501 ? then_stmt
: else_stmt
);
1502 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1503 ? &COND_EXPR_THEN (*stmt_p
)
1504 : &COND_EXPR_ELSE (*stmt_p
));
1507 && TREE_CODE (stmt
) == MODIFY_EXPR
1508 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1509 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1510 *location
= alloc_stmt_list ();
1514 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1515 would be re-introduced during lowering. */
1516 data
->last_goto
= NULL
;
1521 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1523 bool save_may_branch
, save_may_throw
;
1524 bool this_may_branch
, this_may_throw
;
1526 /* Collect may_branch and may_throw information for the body only. */
1527 save_may_branch
= data
->may_branch
;
1528 save_may_throw
= data
->may_throw
;
1529 data
->may_branch
= false;
1530 data
->may_throw
= false;
1531 data
->last_goto
= NULL
;
1533 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1535 this_may_branch
= data
->may_branch
;
1536 this_may_throw
= data
->may_throw
;
1537 data
->may_branch
|= save_may_branch
;
1538 data
->may_throw
|= save_may_throw
;
1539 data
->last_goto
= NULL
;
1541 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1543 /* If the body is empty, then we can emit the FINALLY block without
1544 the enclosing TRY_FINALLY_EXPR. */
1545 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1547 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1548 data
->repeat
= true;
1551 /* If the handler is empty, then we can emit the TRY block without
1552 the enclosing TRY_FINALLY_EXPR. */
1553 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1555 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1556 data
->repeat
= true;
1559 /* If the body neither throws, nor branches, then we can safely
1560 string the TRY and FINALLY blocks together. */
1561 else if (!this_may_branch
&& !this_may_throw
)
1563 tree stmt
= *stmt_p
;
1564 *stmt_p
= TREE_OPERAND (stmt
, 0);
1565 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1566 data
->repeat
= true;
1572 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1574 bool save_may_throw
, this_may_throw
;
1575 tree_stmt_iterator i
;
1578 /* Collect may_throw information for the body only. */
1579 save_may_throw
= data
->may_throw
;
1580 data
->may_throw
= false;
1581 data
->last_goto
= NULL
;
1583 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1585 this_may_throw
= data
->may_throw
;
1586 data
->may_throw
= save_may_throw
;
1588 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1589 if (!this_may_throw
)
1591 if (warn_notreached
)
1592 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1593 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1594 data
->repeat
= true;
1598 /* Process the catch clause specially. We may be able to tell that
1599 no exceptions propagate past this point. */
1601 this_may_throw
= true;
1602 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1603 stmt
= tsi_stmt (i
);
1604 data
->last_goto
= NULL
;
1606 switch (TREE_CODE (stmt
))
1609 for (; !tsi_end_p (i
); tsi_next (&i
))
1611 stmt
= tsi_stmt (i
);
1612 /* If we catch all exceptions, then the body does not
1613 propagate exceptions past this point. */
1614 if (CATCH_TYPES (stmt
) == NULL
)
1615 this_may_throw
= false;
1616 data
->last_goto
= NULL
;
1617 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1621 case EH_FILTER_EXPR
:
1622 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1623 this_may_throw
= false;
1624 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1625 this_may_throw
= false;
1626 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1630 /* Otherwise this is a cleanup. */
1631 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1633 /* If the cleanup is empty, then we can emit the TRY block without
1634 the enclosing TRY_CATCH_EXPR. */
1635 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1637 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1638 data
->repeat
= true;
1642 data
->may_throw
|= this_may_throw
;
1647 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1651 /* First remove anything underneath the BIND_EXPR. */
1652 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1654 /* If the BIND_EXPR has no variables, then we can pull everything
1655 up one level and remove the BIND_EXPR, unless this is the toplevel
1656 BIND_EXPR for the current function or an inlined function.
1658 When this situation occurs we will want to apply this
1659 optimization again. */
1660 block
= BIND_EXPR_BLOCK (*stmt_p
);
1661 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1662 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1664 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1665 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1668 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1669 data
->repeat
= true;
1675 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1677 tree dest
= GOTO_DESTINATION (*stmt_p
);
1679 data
->may_branch
= true;
1680 data
->last_goto
= NULL
;
1682 /* Record the last goto expr, so that we can delete it if unnecessary. */
1683 if (TREE_CODE (dest
) == LABEL_DECL
)
1684 data
->last_goto
= stmt_p
;
1689 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1691 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1693 data
->has_label
= true;
1695 /* We do want to jump across non-local label receiver code. */
1696 if (DECL_NONLOCAL (label
))
1697 data
->last_goto
= NULL
;
1699 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1701 *data
->last_goto
= build_empty_stmt ();
1702 data
->repeat
= true;
1705 /* ??? Add something here to delete unused labels. */
1709 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1710 decl. This allows us to eliminate redundant or useless
1711 calls to "const" functions.
1713 Gimplifier already does the same operation, but we may notice functions
1714 being const and pure once their calls has been gimplified, so we need
1715 to update the flag. */
1718 update_call_expr_flags (tree call
)
1720 tree decl
= get_callee_fndecl (call
);
1723 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1724 TREE_SIDE_EFFECTS (call
) = 0;
1725 if (TREE_NOTHROW (decl
))
1726 TREE_NOTHROW (call
) = 1;
1730 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1733 notice_special_calls (tree t
)
1735 int flags
= call_expr_flags (t
);
1737 if (flags
& ECF_MAY_BE_ALLOCA
)
1738 current_function_calls_alloca
= true;
1739 if (flags
& ECF_RETURNS_TWICE
)
1740 current_function_calls_setjmp
= true;
1744 /* Clear flags set by notice_special_calls. Used by dead code removal
1745 to update the flags. */
1748 clear_special_calls (void)
1750 current_function_calls_alloca
= false;
1751 current_function_calls_setjmp
= false;
1756 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1760 switch (TREE_CODE (t
))
1763 remove_useless_stmts_cond (tp
, data
);
1766 case TRY_FINALLY_EXPR
:
1767 remove_useless_stmts_tf (tp
, data
);
1770 case TRY_CATCH_EXPR
:
1771 remove_useless_stmts_tc (tp
, data
);
1775 remove_useless_stmts_bind (tp
, data
);
1779 remove_useless_stmts_goto (tp
, data
);
1783 remove_useless_stmts_label (tp
, data
);
1788 data
->last_goto
= NULL
;
1789 data
->may_branch
= true;
1794 data
->last_goto
= NULL
;
1795 notice_special_calls (t
);
1796 update_call_expr_flags (t
);
1797 if (tree_could_throw_p (t
))
1798 data
->may_throw
= true;
1802 data
->last_goto
= NULL
;
1804 op
= get_call_expr_in (t
);
1807 update_call_expr_flags (op
);
1808 notice_special_calls (op
);
1810 if (tree_could_throw_p (t
))
1811 data
->may_throw
= true;
1814 case STATEMENT_LIST
:
1816 tree_stmt_iterator i
= tsi_start (t
);
1817 while (!tsi_end_p (i
))
1820 if (IS_EMPTY_STMT (t
))
1826 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1829 if (TREE_CODE (t
) == STATEMENT_LIST
)
1831 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1841 data
->last_goto
= NULL
;
1845 data
->last_goto
= NULL
;
1851 remove_useless_stmts (void)
1853 struct rus_data data
;
1855 clear_special_calls ();
1859 memset (&data
, 0, sizeof (data
));
1860 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1862 while (data
.repeat
);
1866 struct tree_opt_pass pass_remove_useless_stmts
=
1868 "useless", /* name */
1870 remove_useless_stmts
, /* execute */
1873 0, /* static_pass_number */
1875 PROP_gimple_any
, /* properties_required */
1876 0, /* properties_provided */
1877 0, /* properties_destroyed */
1878 0, /* todo_flags_start */
1879 TODO_dump_func
, /* todo_flags_finish */
1884 /* Remove obviously useless statements in basic block BB. */
1887 cfg_remove_useless_stmts_bb (basic_block bb
)
1889 block_stmt_iterator bsi
;
1890 tree stmt
= NULL_TREE
;
1891 tree cond
, var
= NULL_TREE
, val
= NULL_TREE
;
1892 struct var_ann_d
*ann
;
1894 /* Check whether we come here from a condition, and if so, get the
1896 if (EDGE_COUNT (bb
->preds
) != 1
1897 || !(EDGE_PRED (bb
, 0)->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
1900 cond
= COND_EXPR_COND (last_stmt (EDGE_PRED (bb
, 0)->src
));
1902 if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1905 val
= (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
1906 ? boolean_false_node
: boolean_true_node
);
1908 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
1909 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1910 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
))
1912 var
= TREE_OPERAND (cond
, 0);
1913 val
= (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
1914 ? boolean_true_node
: boolean_false_node
);
1918 if (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
)
1919 cond
= invert_truthvalue (cond
);
1920 if (TREE_CODE (cond
) == EQ_EXPR
1921 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1922 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1923 && (TREE_CODE (TREE_OPERAND (cond
, 1)) == VAR_DECL
1924 || TREE_CODE (TREE_OPERAND (cond
, 1)) == PARM_DECL
1925 || TREE_CONSTANT (TREE_OPERAND (cond
, 1))))
1927 var
= TREE_OPERAND (cond
, 0);
1928 val
= TREE_OPERAND (cond
, 1);
1934 /* Only work for normal local variables. */
1935 ann
= var_ann (var
);
1938 || TREE_ADDRESSABLE (var
))
1941 if (! TREE_CONSTANT (val
))
1943 ann
= var_ann (val
);
1946 || TREE_ADDRESSABLE (val
))
1950 /* Ignore floating point variables, since comparison behaves weird for
1952 if (FLOAT_TYPE_P (TREE_TYPE (var
)))
1955 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
);)
1957 stmt
= bsi_stmt (bsi
);
1959 /* If the THEN/ELSE clause merely assigns a value to a variable/parameter
1960 which is already known to contain that value, then remove the useless
1961 THEN/ELSE clause. */
1962 if (TREE_CODE (stmt
) == MODIFY_EXPR
1963 && TREE_OPERAND (stmt
, 0) == var
1964 && operand_equal_p (val
, TREE_OPERAND (stmt
, 1), 0))
1970 /* Invalidate the var if we encounter something that could modify it.
1971 Likewise for the value it was previously set to. Note that we only
1972 consider values that are either a VAR_DECL or PARM_DECL so we
1973 can test for conflict very simply. */
1974 if (TREE_CODE (stmt
) == ASM_EXPR
1975 || (TREE_CODE (stmt
) == MODIFY_EXPR
1976 && (TREE_OPERAND (stmt
, 0) == var
1977 || TREE_OPERAND (stmt
, 0) == val
)))
1985 /* A CFG-aware version of remove_useless_stmts. */
1988 cfg_remove_useless_stmts (void)
1992 #ifdef ENABLE_CHECKING
1993 verify_flow_info ();
1998 cfg_remove_useless_stmts_bb (bb
);
2003 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
2006 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
2010 /* Since this block is no longer reachable, we can just delete all
2011 of its PHI nodes. */
2012 phi
= phi_nodes (bb
);
2015 tree next
= PHI_CHAIN (phi
);
2016 remove_phi_node (phi
, NULL_TREE
);
2020 /* Remove edges to BB's successors. */
2021 while (EDGE_COUNT (bb
->succs
) > 0)
2022 remove_edge (EDGE_SUCC (bb
, 0));
2026 /* Remove statements of basic block BB. */
2029 remove_bb (basic_block bb
)
2031 block_stmt_iterator i
;
2032 #ifdef USE_MAPPED_LOCATION
2033 source_location loc
= UNKNOWN_LOCATION
;
2035 source_locus loc
= 0;
2040 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2041 if (dump_flags
& TDF_DETAILS
)
2043 dump_bb (bb
, dump_file
, 0);
2044 fprintf (dump_file
, "\n");
2048 /* Remove all the instructions in the block. */
2049 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2051 tree stmt
= bsi_stmt (i
);
2052 if (TREE_CODE (stmt
) == LABEL_EXPR
2053 && FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)))
2055 basic_block new_bb
= bb
->prev_bb
;
2056 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
2059 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2063 release_defs (stmt
);
2065 set_bb_for_stmt (stmt
, NULL
);
2069 /* Don't warn for removed gotos. Gotos are often removed due to
2070 jump threading, thus resulting in bogus warnings. Not great,
2071 since this way we lose warnings for gotos in the original
2072 program that are indeed unreachable. */
2073 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2075 #ifdef USE_MAPPED_LOCATION
2076 if (EXPR_HAS_LOCATION (stmt
))
2077 loc
= EXPR_LOCATION (stmt
);
2080 t
= EXPR_LOCUS (stmt
);
2081 if (t
&& LOCATION_LINE (*t
) > 0)
2087 /* If requested, give a warning that the first statement in the
2088 block is unreachable. We walk statements backwards in the
2089 loop above, so the last statement we process is the first statement
2091 #ifdef USE_MAPPED_LOCATION
2092 if (warn_notreached
&& loc
!= UNKNOWN_LOCATION
)
2093 warning ("%Hwill never be executed", &loc
);
2095 if (warn_notreached
&& loc
)
2096 warning ("%Hwill never be executed", loc
);
2099 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2102 /* A list of all the noreturn calls passed to modify_stmt.
2103 cleanup_control_flow uses it to detect cases where a mid-block
2104 indirect call has been turned into a noreturn call. When this
2105 happens, all the instructions after the call are no longer
2106 reachable and must be deleted as dead. */
2108 VEC(tree
) *modified_noreturn_calls
;
2110 /* Try to remove superfluous control structures. */
2113 cleanup_control_flow (void)
2116 block_stmt_iterator bsi
;
2117 bool retval
= false;
2120 /* Detect cases where a mid-block call is now known not to return. */
2121 while (VEC_length (tree
, modified_noreturn_calls
))
2123 stmt
= VEC_pop (tree
, modified_noreturn_calls
);
2124 bb
= bb_for_stmt (stmt
);
2125 if (bb
!= NULL
&& last_stmt (bb
) != stmt
&& noreturn_call_p (stmt
))
2126 split_block (bb
, stmt
);
2131 bsi
= bsi_last (bb
);
2133 if (bsi_end_p (bsi
))
2136 stmt
= bsi_stmt (bsi
);
2137 if (TREE_CODE (stmt
) == COND_EXPR
2138 || TREE_CODE (stmt
) == SWITCH_EXPR
)
2139 retval
|= cleanup_control_expr_graph (bb
, bsi
);
2141 /* If we had a computed goto which has a compile-time determinable
2142 destination, then we can eliminate the goto. */
2143 if (TREE_CODE (stmt
) == GOTO_EXPR
2144 && TREE_CODE (GOTO_DESTINATION (stmt
)) == ADDR_EXPR
2145 && TREE_CODE (TREE_OPERAND (GOTO_DESTINATION (stmt
), 0)) == LABEL_DECL
)
2150 basic_block target_block
;
2151 bool removed_edge
= false;
2153 /* First look at all the outgoing edges. Delete any outgoing
2154 edges which do not go to the right block. For the one
2155 edge which goes to the right block, fix up its flags. */
2156 label
= TREE_OPERAND (GOTO_DESTINATION (stmt
), 0);
2157 target_block
= label_to_block (label
);
2158 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2160 if (e
->dest
!= target_block
)
2162 removed_edge
= true;
2167 /* Turn off the EDGE_ABNORMAL flag. */
2168 EDGE_SUCC (bb
, 0)->flags
&= ~EDGE_ABNORMAL
;
2170 /* And set EDGE_FALLTHRU. */
2171 EDGE_SUCC (bb
, 0)->flags
|= EDGE_FALLTHRU
;
2176 /* If we removed one or more edges, then we will need to fix the
2177 dominators. It may be possible to incrementally update them. */
2179 free_dominance_info (CDI_DOMINATORS
);
2181 /* Remove the GOTO_EXPR as it is not needed. The CFG has all the
2182 relevant information we need. */
2187 /* Check for indirect calls that have been turned into
2189 if (noreturn_call_p (stmt
) && remove_fallthru_edge (bb
->succs
))
2191 free_dominance_info (CDI_DOMINATORS
);
2199 /* Disconnect an unreachable block in the control expression starting
2203 cleanup_control_expr_graph (basic_block bb
, block_stmt_iterator bsi
)
2206 bool retval
= false;
2207 tree expr
= bsi_stmt (bsi
), val
;
2209 if (EDGE_COUNT (bb
->succs
) > 1)
2214 switch (TREE_CODE (expr
))
2217 val
= COND_EXPR_COND (expr
);
2221 val
= SWITCH_COND (expr
);
2222 if (TREE_CODE (val
) != INTEGER_CST
)
2230 taken_edge
= find_taken_edge (bb
, val
);
2234 /* Remove all the edges except the one that is always executed. */
2235 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2237 if (e
!= taken_edge
)
2239 taken_edge
->probability
+= e
->probability
;
2240 taken_edge
->count
+= e
->count
;
2247 if (taken_edge
->probability
> REG_BR_PROB_BASE
)
2248 taken_edge
->probability
= REG_BR_PROB_BASE
;
2251 taken_edge
= EDGE_SUCC (bb
, 0);
2254 taken_edge
->flags
= EDGE_FALLTHRU
;
2256 /* We removed some paths from the cfg. */
2257 free_dominance_info (CDI_DOMINATORS
);
2262 /* Remove any fallthru edge from EV. Return true if an edge was removed. */
2265 remove_fallthru_edge (VEC(edge
) *ev
)
2270 FOR_EACH_EDGE (e
, ei
, ev
)
2271 if ((e
->flags
& EDGE_FALLTHRU
) != 0)
2279 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2280 predicate VAL, return the edge that will be taken out of the block.
2281 If VAL does not match a unique edge, NULL is returned. */
2284 find_taken_edge (basic_block bb
, tree val
)
2288 stmt
= last_stmt (bb
);
2291 gcc_assert (is_ctrl_stmt (stmt
));
2294 if (! is_gimple_min_invariant (val
))
2297 if (TREE_CODE (stmt
) == COND_EXPR
)
2298 return find_taken_edge_cond_expr (bb
, val
);
2300 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2301 return find_taken_edge_switch_expr (bb
, val
);
2303 if (computed_goto_p (stmt
))
2304 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2309 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2310 statement, determine which of the outgoing edges will be taken out of the
2311 block. Return NULL if either edge may be taken. */
2314 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2319 dest
= label_to_block (val
);
2322 e
= find_edge (bb
, dest
);
2323 gcc_assert (e
!= NULL
);
2329 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2330 statement, determine which of the two edges will be taken out of the
2331 block. Return NULL if either edge may be taken. */
2334 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2336 edge true_edge
, false_edge
;
2338 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2340 /* Otherwise, try to determine which branch of the if() will be taken.
2341 If VAL is a constant but it can't be reduced to a 0 or a 1, then
2342 we don't really know which edge will be taken at runtime. This
2343 may happen when comparing addresses (e.g., if (&var1 == 4)). */
2344 if (integer_nonzerop (val
))
2346 else if (integer_zerop (val
))
2353 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2354 statement, determine which edge will be taken out of the block. Return
2355 NULL if any edge may be taken. */
2358 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2360 tree switch_expr
, taken_case
;
2361 basic_block dest_bb
;
2364 switch_expr
= last_stmt (bb
);
2365 taken_case
= find_case_label_for_value (switch_expr
, val
);
2366 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2368 e
= find_edge (bb
, dest_bb
);
2374 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2375 We can make optimal use here of the fact that the case labels are
2376 sorted: We can do a binary search for a case matching VAL. */
2379 find_case_label_for_value (tree switch_expr
, tree val
)
2381 tree vec
= SWITCH_LABELS (switch_expr
);
2382 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2383 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2385 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2387 size_t i
= (high
+ low
) / 2;
2388 tree t
= TREE_VEC_ELT (vec
, i
);
2391 /* Cache the result of comparing CASE_LOW and val. */
2392 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2399 if (CASE_HIGH (t
) == NULL
)
2401 /* A singe-valued case label. */
2407 /* A case range. We can only handle integer ranges. */
2408 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2413 return default_case
;
2417 /* If all the PHI nodes in DEST have alternatives for E1 and E2 and
2418 those alternatives are equal in each of the PHI nodes, then return
2419 true, else return false. */
2422 phi_alternatives_equal (basic_block dest
, edge e1
, edge e2
)
2424 int n1
= e1
->dest_idx
;
2425 int n2
= e2
->dest_idx
;
2428 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
2430 tree val1
= PHI_ARG_DEF (phi
, n1
);
2431 tree val2
= PHI_ARG_DEF (phi
, n2
);
2433 gcc_assert (val1
!= NULL_TREE
);
2434 gcc_assert (val2
!= NULL_TREE
);
2436 if (!operand_equal_for_phi_arg_p (val1
, val2
))
2444 /*---------------------------------------------------------------------------
2446 ---------------------------------------------------------------------------*/
2448 /* Dump tree-specific information of block BB to file OUTF. */
2451 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2453 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2457 /* Dump a basic block on stderr. */
2460 debug_tree_bb (basic_block bb
)
2462 dump_bb (bb
, stderr
, 0);
2466 /* Dump basic block with index N on stderr. */
2469 debug_tree_bb_n (int n
)
2471 debug_tree_bb (BASIC_BLOCK (n
));
2472 return BASIC_BLOCK (n
);
2476 /* Dump the CFG on stderr.
2478 FLAGS are the same used by the tree dumping functions
2479 (see TDF_* in tree.h). */
2482 debug_tree_cfg (int flags
)
2484 dump_tree_cfg (stderr
, flags
);
2488 /* Dump the program showing basic block boundaries on the given FILE.
2490 FLAGS are the same used by the tree dumping functions (see TDF_* in
2494 dump_tree_cfg (FILE *file
, int flags
)
2496 if (flags
& TDF_DETAILS
)
2498 const char *funcname
2499 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2502 fprintf (file
, ";; Function %s\n\n", funcname
);
2503 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2504 n_basic_blocks
, n_edges
, last_basic_block
);
2506 brief_dump_cfg (file
);
2507 fprintf (file
, "\n");
2510 if (flags
& TDF_STATS
)
2511 dump_cfg_stats (file
);
2513 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2517 /* Dump CFG statistics on FILE. */
2520 dump_cfg_stats (FILE *file
)
2522 static long max_num_merged_labels
= 0;
2523 unsigned long size
, total
= 0;
2526 const char * const fmt_str
= "%-30s%-13s%12s\n";
2527 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2528 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2529 const char *funcname
2530 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2533 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2535 fprintf (file
, "---------------------------------------------------------\n");
2536 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2537 fprintf (file
, fmt_str
, "", " instances ", "used ");
2538 fprintf (file
, "---------------------------------------------------------\n");
2540 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2542 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2543 SCALE (size
), LABEL (size
));
2547 n_edges
+= EDGE_COUNT (bb
->succs
);
2548 size
= n_edges
* sizeof (struct edge_def
);
2550 fprintf (file
, fmt_str_1
, "Edges", n_edges
, SCALE (size
), LABEL (size
));
2552 size
= n_basic_blocks
* sizeof (struct bb_ann_d
);
2554 fprintf (file
, fmt_str_1
, "Basic block annotations", n_basic_blocks
,
2555 SCALE (size
), LABEL (size
));
2557 fprintf (file
, "---------------------------------------------------------\n");
2558 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2560 fprintf (file
, "---------------------------------------------------------\n");
2561 fprintf (file
, "\n");
2563 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2564 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2566 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2567 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2569 fprintf (file
, "\n");
2573 /* Dump CFG statistics on stderr. Keep extern so that it's always
2574 linked in the final executable. */
2577 debug_cfg_stats (void)
2579 dump_cfg_stats (stderr
);
2583 /* Dump the flowgraph to a .vcg FILE. */
2586 tree_cfg2vcg (FILE *file
)
2591 const char *funcname
2592 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2594 /* Write the file header. */
2595 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2596 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2597 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2599 /* Write blocks and edges. */
2600 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2602 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2605 if (e
->flags
& EDGE_FAKE
)
2606 fprintf (file
, " linestyle: dotted priority: 10");
2608 fprintf (file
, " linestyle: solid priority: 100");
2610 fprintf (file
, " }\n");
2616 enum tree_code head_code
, end_code
;
2617 const char *head_name
, *end_name
;
2620 tree first
= first_stmt (bb
);
2621 tree last
= last_stmt (bb
);
2625 head_code
= TREE_CODE (first
);
2626 head_name
= tree_code_name
[head_code
];
2627 head_line
= get_lineno (first
);
2630 head_name
= "no-statement";
2634 end_code
= TREE_CODE (last
);
2635 end_name
= tree_code_name
[end_code
];
2636 end_line
= get_lineno (last
);
2639 end_name
= "no-statement";
2641 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2642 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2645 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2647 if (e
->dest
== EXIT_BLOCK_PTR
)
2648 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2650 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2652 if (e
->flags
& EDGE_FAKE
)
2653 fprintf (file
, " priority: 10 linestyle: dotted");
2655 fprintf (file
, " priority: 100 linestyle: solid");
2657 fprintf (file
, " }\n");
2660 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2664 fputs ("}\n\n", file
);
2669 /*---------------------------------------------------------------------------
2670 Miscellaneous helpers
2671 ---------------------------------------------------------------------------*/
2673 /* Return true if T represents a stmt that always transfers control. */
2676 is_ctrl_stmt (tree t
)
2678 return (TREE_CODE (t
) == COND_EXPR
2679 || TREE_CODE (t
) == SWITCH_EXPR
2680 || TREE_CODE (t
) == GOTO_EXPR
2681 || TREE_CODE (t
) == RETURN_EXPR
2682 || TREE_CODE (t
) == RESX_EXPR
);
2686 /* Return true if T is a statement that may alter the flow of control
2687 (e.g., a call to a non-returning function). */
2690 is_ctrl_altering_stmt (tree t
)
2695 call
= get_call_expr_in (t
);
2698 /* A non-pure/const CALL_EXPR alters flow control if the current
2699 function has nonlocal labels. */
2700 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2703 /* A CALL_EXPR also alters control flow if it does not return. */
2704 if (call_expr_flags (call
) & ECF_NORETURN
)
2708 /* If a statement can throw, it alters control flow. */
2709 return tree_can_throw_internal (t
);
2713 /* Return true if T is a computed goto. */
2716 computed_goto_p (tree t
)
2718 return (TREE_CODE (t
) == GOTO_EXPR
2719 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2723 /* Checks whether EXPR is a simple local goto. */
2726 simple_goto_p (tree expr
)
2728 return (TREE_CODE (expr
) == GOTO_EXPR
2729 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2733 /* Return true if T should start a new basic block. PREV_T is the
2734 statement preceding T. It is used when T is a label or a case label.
2735 Labels should only start a new basic block if their previous statement
2736 wasn't a label. Otherwise, sequence of labels would generate
2737 unnecessary basic blocks that only contain a single label. */
2740 stmt_starts_bb_p (tree t
, tree prev_t
)
2745 /* LABEL_EXPRs start a new basic block only if the preceding
2746 statement wasn't a label of the same type. This prevents the
2747 creation of consecutive blocks that have nothing but a single
2749 if (TREE_CODE (t
) == LABEL_EXPR
)
2751 /* Nonlocal and computed GOTO targets always start a new block. */
2752 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2753 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2756 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2758 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2761 cfg_stats
.num_merged_labels
++;
2772 /* Return true if T should end a basic block. */
2775 stmt_ends_bb_p (tree t
)
2777 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2781 /* Add gotos that used to be represented implicitly in the CFG. */
2784 disband_implicit_edges (void)
2787 block_stmt_iterator last
;
2794 last
= bsi_last (bb
);
2795 stmt
= last_stmt (bb
);
2797 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2799 /* Remove superfluous gotos from COND_EXPR branches. Moved
2800 from cfg_remove_useless_stmts here since it violates the
2801 invariants for tree--cfg correspondence and thus fits better
2802 here where we do it anyway. */
2803 e
= find_edge (bb
, bb
->next_bb
);
2806 if (e
->flags
& EDGE_TRUE_VALUE
)
2807 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2808 else if (e
->flags
& EDGE_FALSE_VALUE
)
2809 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2812 e
->flags
|= EDGE_FALLTHRU
;
2818 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2820 /* Remove the RETURN_EXPR if we may fall though to the exit
2822 gcc_assert (EDGE_COUNT (bb
->succs
) == 1);
2823 gcc_assert (EDGE_SUCC (bb
, 0)->dest
== EXIT_BLOCK_PTR
);
2825 if (bb
->next_bb
== EXIT_BLOCK_PTR
2826 && !TREE_OPERAND (stmt
, 0))
2829 EDGE_SUCC (bb
, 0)->flags
|= EDGE_FALLTHRU
;
2834 /* There can be no fallthru edge if the last statement is a control
2836 if (stmt
&& is_ctrl_stmt (stmt
))
2839 /* Find a fallthru edge and emit the goto if necessary. */
2840 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2841 if (e
->flags
& EDGE_FALLTHRU
)
2844 if (!e
|| e
->dest
== bb
->next_bb
)
2847 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2848 label
= tree_block_label (e
->dest
);
2850 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2851 #ifdef USE_MAPPED_LOCATION
2852 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2854 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2856 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2857 e
->flags
&= ~EDGE_FALLTHRU
;
2861 /* Remove block annotations and other datastructures. */
2864 delete_tree_cfg_annotations (void)
2867 if (n_basic_blocks
> 0)
2868 free_blocks_annotations ();
2870 label_to_block_map
= NULL
;
2877 /* Return the first statement in basic block BB. */
2880 first_stmt (basic_block bb
)
2882 block_stmt_iterator i
= bsi_start (bb
);
2883 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2887 /* Return the last statement in basic block BB. */
2890 last_stmt (basic_block bb
)
2892 block_stmt_iterator b
= bsi_last (bb
);
2893 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2897 /* Return a pointer to the last statement in block BB. */
2900 last_stmt_ptr (basic_block bb
)
2902 block_stmt_iterator last
= bsi_last (bb
);
2903 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2907 /* Return the last statement of an otherwise empty block. Return NULL
2908 if the block is totally empty, or if it contains more than one
2912 last_and_only_stmt (basic_block bb
)
2914 block_stmt_iterator i
= bsi_last (bb
);
2920 last
= bsi_stmt (i
);
2925 /* Empty statements should no longer appear in the instruction stream.
2926 Everything that might have appeared before should be deleted by
2927 remove_useless_stmts, and the optimizers should just bsi_remove
2928 instead of smashing with build_empty_stmt.
2930 Thus the only thing that should appear here in a block containing
2931 one executable statement is a label. */
2932 prev
= bsi_stmt (i
);
2933 if (TREE_CODE (prev
) == LABEL_EXPR
)
2940 /* Mark BB as the basic block holding statement T. */
2943 set_bb_for_stmt (tree t
, basic_block bb
)
2945 if (TREE_CODE (t
) == PHI_NODE
)
2947 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2949 tree_stmt_iterator i
;
2950 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2951 set_bb_for_stmt (tsi_stmt (i
), bb
);
2955 stmt_ann_t ann
= get_stmt_ann (t
);
2958 /* If the statement is a label, add the label to block-to-labels map
2959 so that we can speed up edge creation for GOTO_EXPRs. */
2960 if (TREE_CODE (t
) == LABEL_EXPR
)
2964 t
= LABEL_EXPR_LABEL (t
);
2965 uid
= LABEL_DECL_UID (t
);
2968 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2969 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2970 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2973 /* We're moving an existing label. Make sure that we've
2974 removed it from the old block. */
2975 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2976 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2981 /* Finds iterator for STMT. */
2983 extern block_stmt_iterator
2984 bsi_for_stmt (tree stmt
)
2986 block_stmt_iterator bsi
;
2988 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2989 if (bsi_stmt (bsi
) == stmt
)
2995 /* Insert statement (or statement list) T before the statement
2996 pointed-to by iterator I. M specifies how to update iterator I
2997 after insertion (see enum bsi_iterator_update). */
3000 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
3002 set_bb_for_stmt (t
, i
->bb
);
3003 tsi_link_before (&i
->tsi
, t
, m
);
3008 /* Insert statement (or statement list) T after the statement
3009 pointed-to by iterator I. M specifies how to update iterator I
3010 after insertion (see enum bsi_iterator_update). */
3013 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
3015 set_bb_for_stmt (t
, i
->bb
);
3016 tsi_link_after (&i
->tsi
, t
, m
);
3021 /* Remove the statement pointed to by iterator I. The iterator is updated
3022 to the next statement. */
3025 bsi_remove (block_stmt_iterator
*i
)
3027 tree t
= bsi_stmt (*i
);
3028 set_bb_for_stmt (t
, NULL
);
3029 tsi_delink (&i
->tsi
);
3033 /* Move the statement at FROM so it comes right after the statement at TO. */
3036 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
3038 tree stmt
= bsi_stmt (*from
);
3040 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
3044 /* Move the statement at FROM so it comes right before the statement at TO. */
3047 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
3049 tree stmt
= bsi_stmt (*from
);
3051 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
3055 /* Move the statement at FROM to the end of basic block BB. */
3058 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
3060 block_stmt_iterator last
= bsi_last (bb
);
3062 /* Have to check bsi_end_p because it could be an empty block. */
3063 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
3064 bsi_move_before (from
, &last
);
3066 bsi_move_after (from
, &last
);
3070 /* Replace the contents of the statement pointed to by iterator BSI
3071 with STMT. If PRESERVE_EH_INFO is true, the exception handling
3072 information of the original statement is preserved. */
3075 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
3078 tree orig_stmt
= bsi_stmt (*bsi
);
3080 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
3081 set_bb_for_stmt (stmt
, bsi
->bb
);
3083 /* Preserve EH region information from the original statement, if
3084 requested by the caller. */
3085 if (preserve_eh_info
)
3087 eh_region
= lookup_stmt_eh_region (orig_stmt
);
3089 add_stmt_to_eh_region (stmt
, eh_region
);
3092 *bsi_stmt_ptr (*bsi
) = stmt
;
3097 /* Insert the statement pointed-to by BSI into edge E. Every attempt
3098 is made to place the statement in an existing basic block, but
3099 sometimes that isn't possible. When it isn't possible, the edge is
3100 split and the statement is added to the new block.
3102 In all cases, the returned *BSI points to the correct location. The
3103 return value is true if insertion should be done after the location,
3104 or false if it should be done before the location. If new basic block
3105 has to be created, it is stored in *NEW_BB. */
3108 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
3109 basic_block
*new_bb
)
3111 basic_block dest
, src
;
3117 /* If the destination has one predecessor which has no PHI nodes,
3118 insert there. Except for the exit block.
3120 The requirement for no PHI nodes could be relaxed. Basically we
3121 would have to examine the PHIs to prove that none of them used
3122 the value set by the statement we want to insert on E. That
3123 hardly seems worth the effort. */
3124 if (EDGE_COUNT (dest
->preds
) == 1
3125 && ! phi_nodes (dest
)
3126 && dest
!= EXIT_BLOCK_PTR
)
3128 *bsi
= bsi_start (dest
);
3129 if (bsi_end_p (*bsi
))
3132 /* Make sure we insert after any leading labels. */
3133 tmp
= bsi_stmt (*bsi
);
3134 while (TREE_CODE (tmp
) == LABEL_EXPR
)
3137 if (bsi_end_p (*bsi
))
3139 tmp
= bsi_stmt (*bsi
);
3142 if (bsi_end_p (*bsi
))
3144 *bsi
= bsi_last (dest
);
3151 /* If the source has one successor, the edge is not abnormal and
3152 the last statement does not end a basic block, insert there.
3153 Except for the entry block. */
3155 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3156 && EDGE_COUNT (src
->succs
) == 1
3157 && src
!= ENTRY_BLOCK_PTR
)
3159 *bsi
= bsi_last (src
);
3160 if (bsi_end_p (*bsi
))
3163 tmp
= bsi_stmt (*bsi
);
3164 if (!stmt_ends_bb_p (tmp
))
3167 /* Insert code just before returning the value. We may need to decompose
3168 the return in the case it contains non-trivial operand. */
3169 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3171 tree op
= TREE_OPERAND (tmp
, 0);
3172 if (!is_gimple_val (op
))
3174 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3175 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3176 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3183 /* Otherwise, create a new basic block, and split this edge. */
3184 dest
= split_edge (e
);
3187 e
= EDGE_PRED (dest
, 0);
3192 /* This routine will commit all pending edge insertions, creating any new
3193 basic blocks which are necessary. */
3196 bsi_commit_edge_inserts (void)
3202 bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR
, 0), NULL
);
3205 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3206 bsi_commit_one_edge_insert (e
, NULL
);
3210 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3211 to this block, otherwise set it to NULL. */
3214 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3218 if (PENDING_STMT (e
))
3220 block_stmt_iterator bsi
;
3221 tree stmt
= PENDING_STMT (e
);
3223 PENDING_STMT (e
) = NULL_TREE
;
3225 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3226 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3228 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3233 /* Add STMT to the pending list of edge E. No actual insertion is
3234 made until a call to bsi_commit_edge_inserts () is made. */
3237 bsi_insert_on_edge (edge e
, tree stmt
)
3239 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3242 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3243 block has to be created, it is returned. */
3246 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3248 block_stmt_iterator bsi
;
3249 basic_block new_bb
= NULL
;
3251 gcc_assert (!PENDING_STMT (e
));
3253 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3254 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3256 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3261 /*---------------------------------------------------------------------------
3262 Tree specific functions for CFG manipulation
3263 ---------------------------------------------------------------------------*/
3265 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3268 reinstall_phi_args (edge new_edge
, edge old_edge
)
3272 if (!PENDING_STMT (old_edge
))
3275 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3277 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3279 tree result
= TREE_PURPOSE (var
);
3280 tree arg
= TREE_VALUE (var
);
3282 gcc_assert (result
== PHI_RESULT (phi
));
3284 add_phi_arg (phi
, arg
, new_edge
);
3287 PENDING_STMT (old_edge
) = NULL
;
3290 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3291 Abort on abnormal edges. */
3294 tree_split_edge (edge edge_in
)
3296 basic_block new_bb
, after_bb
, dest
, src
;
3299 /* Abnormal edges cannot be split. */
3300 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3303 dest
= edge_in
->dest
;
3305 /* Place the new block in the block list. Try to keep the new block
3306 near its "logical" location. This is of most help to humans looking
3307 at debugging dumps. */
3308 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3309 after_bb
= edge_in
->src
;
3311 after_bb
= dest
->prev_bb
;
3313 new_bb
= create_empty_bb (after_bb
);
3314 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3315 new_bb
->count
= edge_in
->count
;
3316 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3317 new_edge
->probability
= REG_BR_PROB_BASE
;
3318 new_edge
->count
= edge_in
->count
;
3320 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3322 reinstall_phi_args (new_edge
, e
);
3328 /* Return true when BB has label LABEL in it. */
3331 has_label_p (basic_block bb
, tree label
)
3333 block_stmt_iterator bsi
;
3335 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3337 tree stmt
= bsi_stmt (bsi
);
3339 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3341 if (LABEL_EXPR_LABEL (stmt
) == label
)
3348 /* Callback for walk_tree, check that all elements with address taken are
3349 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3350 inside a PHI node. */
3353 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3356 bool in_phi
= (data
!= NULL
);
3361 /* Check operand N for being valid GIMPLE and give error MSG if not.
3362 We check for constants explicitly since they are not considered
3363 gimple invariants if they overflowed. */
3364 #define CHECK_OP(N, MSG) \
3365 do { if (!CONSTANT_CLASS_P (TREE_OPERAND (t, N)) \
3366 && !is_gimple_val (TREE_OPERAND (t, N))) \
3367 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3369 switch (TREE_CODE (t
))
3372 if (SSA_NAME_IN_FREE_LIST (t
))
3374 error ("SSA name in freelist but still referenced");
3380 x
= TREE_OPERAND (t
, 0);
3381 if (TREE_CODE (x
) == BIT_FIELD_REF
3382 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3384 error ("GIMPLE register modified with BIT_FIELD_REF");
3390 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3391 dead PHIs that take the address of something. But if the PHI
3392 result is dead, the fact that it takes the address of anything
3393 is irrelevant. Because we can not tell from here if a PHI result
3394 is dead, we just skip this check for PHIs altogether. This means
3395 we may be missing "valid" checks, but what can you do?
3396 This was PR19217. */
3400 /* Skip any references (they will be checked when we recurse down the
3401 tree) and ensure that any variable used as a prefix is marked
3403 for (x
= TREE_OPERAND (t
, 0);
3404 handled_component_p (x
);
3405 x
= TREE_OPERAND (x
, 0))
3408 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3410 if (!TREE_ADDRESSABLE (x
))
3412 error ("address taken, but ADDRESSABLE bit not set");
3418 x
= COND_EXPR_COND (t
);
3419 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3421 error ("non-boolean used in condition");
3428 case FIX_TRUNC_EXPR
:
3430 case FIX_FLOOR_EXPR
:
3431 case FIX_ROUND_EXPR
:
3436 case NON_LVALUE_EXPR
:
3437 case TRUTH_NOT_EXPR
:
3438 CHECK_OP (0, "Invalid operand to unary operator");
3445 case ARRAY_RANGE_REF
:
3447 case VIEW_CONVERT_EXPR
:
3448 /* We have a nest of references. Verify that each of the operands
3449 that determine where to reference is either a constant or a variable,
3450 verify that the base is valid, and then show we've already checked
3452 while (handled_component_p (t
))
3454 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3455 CHECK_OP (2, "Invalid COMPONENT_REF offset operator");
3456 else if (TREE_CODE (t
) == ARRAY_REF
3457 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3459 CHECK_OP (1, "Invalid array index.");
3460 if (TREE_OPERAND (t
, 2))
3461 CHECK_OP (2, "Invalid array lower bound.");
3462 if (TREE_OPERAND (t
, 3))
3463 CHECK_OP (3, "Invalid array stride.");
3465 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3467 CHECK_OP (1, "Invalid operand to BIT_FIELD_REF");
3468 CHECK_OP (2, "Invalid operand to BIT_FIELD_REF");
3471 t
= TREE_OPERAND (t
, 0);
3474 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3476 error ("Invalid reference prefix.");
3488 case UNORDERED_EXPR
:
3499 case TRUNC_DIV_EXPR
:
3501 case FLOOR_DIV_EXPR
:
3502 case ROUND_DIV_EXPR
:
3503 case TRUNC_MOD_EXPR
:
3505 case FLOOR_MOD_EXPR
:
3506 case ROUND_MOD_EXPR
:
3508 case EXACT_DIV_EXPR
:
3518 CHECK_OP (0, "Invalid operand to binary operator");
3519 CHECK_OP (1, "Invalid operand to binary operator");
3531 /* Verify STMT, return true if STMT is not in GIMPLE form.
3532 TODO: Implement type checking. */
3535 verify_stmt (tree stmt
, bool last_in_block
)
3539 if (!is_gimple_stmt (stmt
))
3541 error ("Is not a valid GIMPLE statement.");
3545 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3548 debug_generic_stmt (addr
);
3552 /* If the statement is marked as part of an EH region, then it is
3553 expected that the statement could throw. Verify that when we
3554 have optimizations that simplify statements such that we prove
3555 that they cannot throw, that we update other data structures
3557 if (lookup_stmt_eh_region (stmt
) >= 0)
3559 if (!tree_could_throw_p (stmt
))
3561 error ("Statement marked for throw, but doesn%'t.");
3564 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3566 error ("Statement marked for throw in middle of block.");
3574 debug_generic_stmt (stmt
);
3579 /* Return true when the T can be shared. */
3582 tree_node_can_be_shared (tree t
)
3584 if (IS_TYPE_OR_DECL_P (t
)
3585 /* We check for constants explicitly since they are not considered
3586 gimple invariants if they overflowed. */
3587 || CONSTANT_CLASS_P (t
)
3588 || is_gimple_min_invariant (t
)
3589 || TREE_CODE (t
) == SSA_NAME
3590 || t
== error_mark_node
)
3593 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3596 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3597 /* We check for constants explicitly since they are not considered
3598 gimple invariants if they overflowed. */
3599 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3600 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3601 || (TREE_CODE (t
) == COMPONENT_REF
3602 || TREE_CODE (t
) == REALPART_EXPR
3603 || TREE_CODE (t
) == IMAGPART_EXPR
))
3604 t
= TREE_OPERAND (t
, 0);
3613 /* Called via walk_trees. Verify tree sharing. */
3616 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3618 htab_t htab
= (htab_t
) data
;
3621 if (tree_node_can_be_shared (*tp
))
3623 *walk_subtrees
= false;
3627 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3636 /* Verify the GIMPLE statement chain. */
3642 block_stmt_iterator bsi
;
3647 timevar_push (TV_TREE_STMT_VERIFY
);
3648 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3655 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3657 int phi_num_args
= PHI_NUM_ARGS (phi
);
3659 for (i
= 0; i
< phi_num_args
; i
++)
3661 tree t
= PHI_ARG_DEF (phi
, i
);
3664 /* Addressable variables do have SSA_NAMEs but they
3665 are not considered gimple values. */
3666 if (TREE_CODE (t
) != SSA_NAME
3667 && TREE_CODE (t
) != FUNCTION_DECL
3668 && !is_gimple_val (t
))
3670 error ("PHI def is not a GIMPLE value");
3671 debug_generic_stmt (phi
);
3672 debug_generic_stmt (t
);
3676 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3679 debug_generic_stmt (addr
);
3683 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3686 error ("Incorrect sharing of tree nodes");
3687 debug_generic_stmt (phi
);
3688 debug_generic_stmt (addr
);
3694 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3696 tree stmt
= bsi_stmt (bsi
);
3698 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3699 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3702 error ("Incorrect sharing of tree nodes");
3703 debug_generic_stmt (stmt
);
3704 debug_generic_stmt (addr
);
3711 internal_error ("verify_stmts failed.");
3714 timevar_pop (TV_TREE_STMT_VERIFY
);
3718 /* Verifies that the flow information is OK. */
3721 tree_verify_flow_info (void)
3725 block_stmt_iterator bsi
;
3730 if (ENTRY_BLOCK_PTR
->stmt_list
)
3732 error ("ENTRY_BLOCK has a statement list associated with it\n");
3736 if (EXIT_BLOCK_PTR
->stmt_list
)
3738 error ("EXIT_BLOCK has a statement list associated with it\n");
3742 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3743 if (e
->flags
& EDGE_FALLTHRU
)
3745 error ("Fallthru to exit from bb %d\n", e
->src
->index
);
3751 bool found_ctrl_stmt
= false;
3755 /* Skip labels on the start of basic block. */
3756 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3758 tree prev_stmt
= stmt
;
3760 stmt
= bsi_stmt (bsi
);
3762 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3765 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3767 error ("Nonlocal label %s is not first "
3768 "in a sequence of labels in bb %d",
3769 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3774 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3776 error ("Label %s to block does not match in bb %d\n",
3777 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3782 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3783 != current_function_decl
)
3785 error ("Label %s has incorrect context in bb %d\n",
3786 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3792 /* Verify that body of basic block BB is free of control flow. */
3793 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3795 tree stmt
= bsi_stmt (bsi
);
3797 if (found_ctrl_stmt
)
3799 error ("Control flow in the middle of basic block %d\n",
3804 if (stmt_ends_bb_p (stmt
))
3805 found_ctrl_stmt
= true;
3807 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3809 error ("Label %s in the middle of basic block %d\n",
3810 IDENTIFIER_POINTER (DECL_NAME (stmt
)),
3815 bsi
= bsi_last (bb
);
3816 if (bsi_end_p (bsi
))
3819 stmt
= bsi_stmt (bsi
);
3821 if (is_ctrl_stmt (stmt
))
3823 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3824 if (e
->flags
& EDGE_FALLTHRU
)
3826 error ("Fallthru edge after a control statement in bb %d \n",
3832 switch (TREE_CODE (stmt
))
3838 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3839 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3841 error ("Structured COND_EXPR at the end of bb %d\n", bb
->index
);
3845 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3847 if (!true_edge
|| !false_edge
3848 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3849 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3850 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3851 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3852 || EDGE_COUNT (bb
->succs
) >= 3)
3854 error ("Wrong outgoing edge flags at end of bb %d\n",
3859 if (!has_label_p (true_edge
->dest
,
3860 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3862 error ("%<then%> label does not match edge at end of bb %d\n",
3867 if (!has_label_p (false_edge
->dest
,
3868 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3870 error ("%<else%> label does not match edge at end of bb %d\n",
3878 if (simple_goto_p (stmt
))
3880 error ("Explicit goto at end of bb %d\n", bb
->index
);
3885 /* FIXME. We should double check that the labels in the
3886 destination blocks have their address taken. */
3887 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3888 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3889 | EDGE_FALSE_VALUE
))
3890 || !(e
->flags
& EDGE_ABNORMAL
))
3892 error ("Wrong outgoing edge flags at end of bb %d\n",
3900 if (EDGE_COUNT (bb
->succs
) != 1
3901 || (EDGE_SUCC (bb
, 0)->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3902 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3904 error ("Wrong outgoing edge flags at end of bb %d\n", bb
->index
);
3907 if (EDGE_SUCC (bb
, 0)->dest
!= EXIT_BLOCK_PTR
)
3909 error ("Return edge does not point to exit in bb %d\n",
3922 vec
= SWITCH_LABELS (stmt
);
3923 n
= TREE_VEC_LENGTH (vec
);
3925 /* Mark all the destination basic blocks. */
3926 for (i
= 0; i
< n
; ++i
)
3928 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3929 basic_block label_bb
= label_to_block (lab
);
3931 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3932 label_bb
->aux
= (void *)1;
3935 /* Verify that the case labels are sorted. */
3936 prev
= TREE_VEC_ELT (vec
, 0);
3937 for (i
= 1; i
< n
- 1; ++i
)
3939 tree c
= TREE_VEC_ELT (vec
, i
);
3942 error ("Found default case not at end of case vector");
3946 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3948 error ("Case labels not sorted:\n ");
3949 print_generic_expr (stderr
, prev
, 0);
3950 fprintf (stderr
," is greater than ");
3951 print_generic_expr (stderr
, c
, 0);
3952 fprintf (stderr
," but comes before it.\n");
3957 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3959 error ("No default case found at end of case vector");
3963 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3967 error ("Extra outgoing edge %d->%d\n",
3968 bb
->index
, e
->dest
->index
);
3971 e
->dest
->aux
= (void *)2;
3972 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3973 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3975 error ("Wrong outgoing edge flags at end of bb %d\n",
3981 /* Check that we have all of them. */
3982 for (i
= 0; i
< n
; ++i
)
3984 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3985 basic_block label_bb
= label_to_block (lab
);
3987 if (label_bb
->aux
!= (void *)2)
3989 error ("Missing edge %i->%i",
3990 bb
->index
, label_bb
->index
);
3995 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3996 e
->dest
->aux
= (void *)0;
4003 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
4004 verify_dominators (CDI_DOMINATORS
);
4010 /* Updates phi nodes after creating a forwarder block joined
4011 by edge FALLTHRU. */
4014 tree_make_forwarder_block (edge fallthru
)
4018 basic_block dummy
, bb
;
4019 tree phi
, new_phi
, var
;
4021 dummy
= fallthru
->src
;
4022 bb
= fallthru
->dest
;
4024 if (EDGE_COUNT (bb
->preds
) == 1)
4027 /* If we redirected a branch we must create new phi nodes at the
4029 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
4031 var
= PHI_RESULT (phi
);
4032 new_phi
= create_phi_node (var
, bb
);
4033 SSA_NAME_DEF_STMT (var
) = new_phi
;
4034 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
4035 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
4038 /* Ensure that the PHI node chain is in the same order. */
4039 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
4041 /* Add the arguments we have stored on edges. */
4042 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4047 flush_pending_stmts (e
);
4052 /* Return true if basic block BB does nothing except pass control
4053 flow to another block and that we can safely insert a label at
4054 the start of the successor block.
4056 As a precondition, we require that BB be not equal to
4060 tree_forwarder_block_p (basic_block bb
, bool phi_wanted
)
4062 block_stmt_iterator bsi
;
4064 /* BB must have a single outgoing edge. */
4065 if (EDGE_COUNT (bb
->succs
) != 1
4066 /* If PHI_WANTED is false, BB must not have any PHI nodes.
4067 Otherwise, BB must have PHI nodes. */
4068 || (phi_nodes (bb
) != NULL_TREE
) != phi_wanted
4069 /* BB may not be a predecessor of EXIT_BLOCK_PTR. */
4070 || EDGE_SUCC (bb
, 0)->dest
== EXIT_BLOCK_PTR
4071 /* Nor should this be an infinite loop. */
4072 || EDGE_SUCC (bb
, 0)->dest
== bb
4073 /* BB may not have an abnormal outgoing edge. */
4074 || (EDGE_SUCC (bb
, 0)->flags
& EDGE_ABNORMAL
))
4078 gcc_assert (bb
!= ENTRY_BLOCK_PTR
);
4081 /* Now walk through the statements backward. We can ignore labels,
4082 anything else means this is not a forwarder block. */
4083 for (bsi
= bsi_last (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4085 tree stmt
= bsi_stmt (bsi
);
4087 switch (TREE_CODE (stmt
))
4090 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
4099 if (find_edge (ENTRY_BLOCK_PTR
, bb
))
4105 /* Return true if BB has at least one abnormal incoming edge. */
4108 has_abnormal_incoming_edge_p (basic_block bb
)
4113 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4114 if (e
->flags
& EDGE_ABNORMAL
)
4120 /* Removes forwarder block BB. Returns false if this failed. If a new
4121 forwarder block is created due to redirection of edges, it is
4122 stored to worklist. */
4125 remove_forwarder_block (basic_block bb
, basic_block
**worklist
)
4127 edge succ
= EDGE_SUCC (bb
, 0), e
, s
;
4128 basic_block dest
= succ
->dest
;
4132 block_stmt_iterator bsi
, bsi_to
;
4133 bool seen_abnormal_edge
= false;
4135 /* We check for infinite loops already in tree_forwarder_block_p.
4136 However it may happen that the infinite loop is created
4137 afterwards due to removal of forwarders. */
4141 /* If the destination block consists of a nonlocal label, do not merge
4143 label
= first_stmt (dest
);
4145 && TREE_CODE (label
) == LABEL_EXPR
4146 && DECL_NONLOCAL (LABEL_EXPR_LABEL (label
)))
4149 /* If there is an abnormal edge to basic block BB, but not into
4150 dest, problems might occur during removal of the phi node at out
4151 of ssa due to overlapping live ranges of registers.
4153 If there is an abnormal edge in DEST, the problems would occur
4154 anyway since cleanup_dead_labels would then merge the labels for
4155 two different eh regions, and rest of exception handling code
4158 So if there is an abnormal edge to BB, proceed only if there is
4159 no abnormal edge to DEST and there are no phi nodes in DEST. */
4160 if (has_abnormal_incoming_edge_p (bb
))
4162 seen_abnormal_edge
= true;
4164 if (has_abnormal_incoming_edge_p (dest
)
4165 || phi_nodes (dest
) != NULL_TREE
)
4169 /* If there are phi nodes in DEST, and some of the blocks that are
4170 predecessors of BB are also predecessors of DEST, check that the
4171 phi node arguments match. */
4172 if (phi_nodes (dest
))
4174 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4176 s
= find_edge (e
->src
, dest
);
4180 if (!phi_alternatives_equal (dest
, succ
, s
))
4185 /* Redirect the edges. */
4186 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4188 if (e
->flags
& EDGE_ABNORMAL
)
4190 /* If there is an abnormal edge, redirect it anyway, and
4191 move the labels to the new block to make it legal. */
4192 s
= redirect_edge_succ_nodup (e
, dest
);
4195 s
= redirect_edge_and_branch (e
, dest
);
4199 /* Create arguments for the phi nodes, since the edge was not
4201 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
4202 add_phi_arg (phi
, PHI_ARG_DEF (phi
, succ
->dest_idx
), s
);
4206 /* The source basic block might become a forwarder. We know
4207 that it was not a forwarder before, since it used to have
4208 at least two outgoing edges, so we may just add it to
4210 if (tree_forwarder_block_p (s
->src
, false))
4211 *(*worklist
)++ = s
->src
;
4215 if (seen_abnormal_edge
)
4217 /* Move the labels to the new block, so that the redirection of
4218 the abnormal edges works. */
4220 bsi_to
= bsi_start (dest
);
4221 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
4223 label
= bsi_stmt (bsi
);
4224 gcc_assert (TREE_CODE (label
) == LABEL_EXPR
);
4226 bsi_insert_before (&bsi_to
, label
, BSI_CONTINUE_LINKING
);
4230 /* Update the dominators. */
4231 if (dom_info_available_p (CDI_DOMINATORS
))
4233 basic_block dom
, dombb
, domdest
;
4235 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
4236 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
4239 /* Shortcut to avoid calling (relatively expensive)
4240 nearest_common_dominator unless necessary. */
4244 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
4246 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
4249 /* And kill the forwarder block. */
4250 delete_basic_block (bb
);
4255 /* Removes forwarder blocks. */
4258 cleanup_forwarder_blocks (void)
4261 bool changed
= false;
4262 basic_block
*worklist
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4263 basic_block
*current
= worklist
;
4267 if (tree_forwarder_block_p (bb
, false))
4271 while (current
!= worklist
)
4274 changed
|= remove_forwarder_block (bb
, ¤t
);
4281 /* Merge the PHI nodes at BB into those at BB's sole successor. */
4284 remove_forwarder_block_with_phi (basic_block bb
)
4286 edge succ
= EDGE_SUCC (bb
, 0);
4287 basic_block dest
= succ
->dest
;
4289 basic_block dombb
, domdest
, dom
;
4291 /* We check for infinite loops already in tree_forwarder_block_p.
4292 However it may happen that the infinite loop is created
4293 afterwards due to removal of forwarders. */
4297 /* If the destination block consists of a nonlocal label, do not
4299 label
= first_stmt (dest
);
4301 && TREE_CODE (label
) == LABEL_EXPR
4302 && DECL_NONLOCAL (LABEL_EXPR_LABEL (label
)))
4305 /* Redirect each incoming edge to BB to DEST. */
4306 while (EDGE_COUNT (bb
->preds
) > 0)
4308 edge e
= EDGE_PRED (bb
, 0), s
;
4311 s
= find_edge (e
->src
, dest
);
4314 /* We already have an edge S from E->src to DEST. If S and
4315 E->dest's sole successor edge have the same PHI arguments
4316 at DEST, redirect S to DEST. */
4317 if (phi_alternatives_equal (dest
, s
, succ
))
4319 e
= redirect_edge_and_branch (e
, dest
);
4320 PENDING_STMT (e
) = NULL_TREE
;
4324 /* PHI arguments are different. Create a forwarder block by
4325 splitting E so that we can merge PHI arguments on E to
4327 e
= EDGE_SUCC (split_edge (e
), 0);
4330 s
= redirect_edge_and_branch (e
, dest
);
4332 /* redirect_edge_and_branch must not create a new edge. */
4333 gcc_assert (s
== e
);
4335 /* Add to the PHI nodes at DEST each PHI argument removed at the
4336 destination of E. */
4337 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
4339 tree def
= PHI_ARG_DEF (phi
, succ
->dest_idx
);
4341 if (TREE_CODE (def
) == SSA_NAME
)
4345 /* If DEF is one of the results of PHI nodes removed during
4346 redirection, replace it with the PHI argument that used
4348 for (var
= PENDING_STMT (e
); var
; var
= TREE_CHAIN (var
))
4350 tree old_arg
= TREE_PURPOSE (var
);
4351 tree new_arg
= TREE_VALUE (var
);
4361 add_phi_arg (phi
, def
, s
);
4364 PENDING_STMT (e
) = NULL
;
4367 /* Update the dominators. */
4368 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
4369 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
4372 /* Shortcut to avoid calling (relatively expensive)
4373 nearest_common_dominator unless necessary. */
4377 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
4379 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
4381 /* Remove BB since all of BB's incoming edges have been redirected
4383 delete_basic_block (bb
);
4386 /* This pass merges PHI nodes if one feeds into another. For example,
4387 suppose we have the following:
4394 # tem_6 = PHI <tem_17(8), tem_23(7)>;
4397 # tem_3 = PHI <tem_6(9), tem_2(5)>;
4400 Then we merge the first PHI node into the second one like so:
4402 goto <bb 9> (<L10>);
4407 # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>;
4412 merge_phi_nodes (void)
4414 basic_block
*worklist
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4415 basic_block
*current
= worklist
;
4418 calculate_dominance_info (CDI_DOMINATORS
);
4420 /* Find all PHI nodes that we may be able to merge. */
4425 /* Look for a forwarder block with PHI nodes. */
4426 if (!tree_forwarder_block_p (bb
, true))
4429 dest
= EDGE_SUCC (bb
, 0)->dest
;
4431 /* We have to feed into another basic block with PHI
4433 if (!phi_nodes (dest
)
4434 /* We don't want to deal with a basic block with
4436 || has_abnormal_incoming_edge_p (bb
))
4439 if (!dominated_by_p (CDI_DOMINATORS
, dest
, bb
))
4441 /* If BB does not dominate DEST, then the PHI nodes at
4442 DEST must be the only users of the results of the PHI
4448 /* Now let's drain WORKLIST. */
4449 while (current
!= worklist
)
4452 remove_forwarder_block_with_phi (bb
);
4459 gate_merge_phi (void)
4464 struct tree_opt_pass pass_merge_phi
= {
4465 "mergephi", /* name */
4466 gate_merge_phi
, /* gate */
4467 merge_phi_nodes
, /* execute */
4470 0, /* static_pass_number */
4471 TV_TREE_MERGE_PHI
, /* tv_id */
4472 PROP_cfg
| PROP_ssa
, /* properties_required */
4473 0, /* properties_provided */
4474 0, /* properties_destroyed */
4475 0, /* todo_flags_start */
4476 TODO_dump_func
| TODO_ggc_collect
/* todo_flags_finish */
4481 /* Return a non-special label in the head of basic block BLOCK.
4482 Create one if it doesn't exist. */
4485 tree_block_label (basic_block bb
)
4487 block_stmt_iterator i
, s
= bsi_start (bb
);
4491 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4493 stmt
= bsi_stmt (i
);
4494 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4496 label
= LABEL_EXPR_LABEL (stmt
);
4497 if (!DECL_NONLOCAL (label
))
4500 bsi_move_before (&i
, &s
);
4505 label
= create_artificial_label ();
4506 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4507 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4512 /* Attempt to perform edge redirection by replacing a possibly complex
4513 jump instruction by a goto or by removing the jump completely.
4514 This can apply only if all edges now point to the same block. The
4515 parameters and return values are equivalent to
4516 redirect_edge_and_branch. */
4519 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4521 basic_block src
= e
->src
;
4522 block_stmt_iterator b
;
4525 /* We can replace or remove a complex jump only when we have exactly
4527 if (EDGE_COUNT (src
->succs
) != 2
4528 /* Verify that all targets will be TARGET. Specifically, the
4529 edge that is not E must also go to TARGET. */
4530 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4536 stmt
= bsi_stmt (b
);
4538 if (TREE_CODE (stmt
) == COND_EXPR
4539 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4542 e
= ssa_redirect_edge (e
, target
);
4543 e
->flags
= EDGE_FALLTHRU
;
4551 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4552 edge representing the redirected branch. */
4555 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4557 basic_block bb
= e
->src
;
4558 block_stmt_iterator bsi
;
4562 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4565 if (e
->src
!= ENTRY_BLOCK_PTR
4566 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4569 if (e
->dest
== dest
)
4572 label
= tree_block_label (dest
);
4574 bsi
= bsi_last (bb
);
4575 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4577 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4580 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4581 ? COND_EXPR_THEN (stmt
)
4582 : COND_EXPR_ELSE (stmt
));
4583 GOTO_DESTINATION (stmt
) = label
;
4587 /* No non-abnormal edges should lead from a non-simple goto, and
4588 simple ones should be represented implicitly. */
4593 tree cases
= get_cases_for_edge (e
, stmt
);
4595 /* If we have a list of cases associated with E, then use it
4596 as it's a lot faster than walking the entire case vector. */
4599 edge e2
= find_edge (e
->src
, dest
);
4606 CASE_LABEL (cases
) = label
;
4607 cases
= TREE_CHAIN (cases
);
4610 /* If there was already an edge in the CFG, then we need
4611 to move all the cases associated with E to E2. */
4614 tree cases2
= get_cases_for_edge (e2
, stmt
);
4616 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4617 TREE_CHAIN (cases2
) = first
;
4622 tree vec
= SWITCH_LABELS (stmt
);
4623 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4625 for (i
= 0; i
< n
; i
++)
4627 tree elt
= TREE_VEC_ELT (vec
, i
);
4629 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4630 CASE_LABEL (elt
) = label
;
4639 e
->flags
|= EDGE_FALLTHRU
;
4643 /* Otherwise it must be a fallthru edge, and we don't need to
4644 do anything besides redirecting it. */
4645 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4649 /* Update/insert PHI nodes as necessary. */
4651 /* Now update the edges in the CFG. */
4652 e
= ssa_redirect_edge (e
, dest
);
4658 /* Simple wrapper, as we can always redirect fallthru edges. */
4661 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4663 e
= tree_redirect_edge_and_branch (e
, dest
);
4670 /* Splits basic block BB after statement STMT (but at least after the
4671 labels). If STMT is NULL, BB is split just after the labels. */
4674 tree_split_block (basic_block bb
, void *stmt
)
4676 block_stmt_iterator bsi
, bsi_tgt
;
4682 new_bb
= create_empty_bb (bb
);
4684 /* Redirect the outgoing edges. */
4685 new_bb
->succs
= bb
->succs
;
4687 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4690 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4693 /* Move everything from BSI to the new basic block. */
4694 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4696 act
= bsi_stmt (bsi
);
4697 if (TREE_CODE (act
) == LABEL_EXPR
)
4710 bsi_tgt
= bsi_start (new_bb
);
4711 while (!bsi_end_p (bsi
))
4713 act
= bsi_stmt (bsi
);
4715 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4722 /* Moves basic block BB after block AFTER. */
4725 tree_move_block_after (basic_block bb
, basic_block after
)
4727 if (bb
->prev_bb
== after
)
4731 link_block (bb
, after
);
4737 /* Return true if basic_block can be duplicated. */
4740 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4745 /* Create a duplicate of the basic block BB. NOTE: This does not
4746 preserve SSA form. */
4749 tree_duplicate_bb (basic_block bb
)
4752 block_stmt_iterator bsi
, bsi_tgt
;
4754 ssa_op_iter op_iter
;
4756 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4758 /* First copy the phi nodes. We do not copy phi node arguments here,
4759 since the edges are not ready yet. Keep the chain of phi nodes in
4760 the same order, so that we can add them later. */
4761 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4763 mark_for_rewrite (PHI_RESULT (phi
));
4764 create_phi_node (PHI_RESULT (phi
), new_bb
);
4766 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4768 bsi_tgt
= bsi_start (new_bb
);
4769 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4771 tree stmt
= bsi_stmt (bsi
);
4774 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4777 /* Record the definitions. */
4778 get_stmt_operands (stmt
);
4780 FOR_EACH_SSA_TREE_OPERAND (val
, stmt
, op_iter
, SSA_OP_ALL_DEFS
)
4781 mark_for_rewrite (val
);
4783 copy
= unshare_expr (stmt
);
4785 /* Copy also the virtual operands. */
4786 get_stmt_ann (copy
);
4787 copy_virtual_operands (copy
, stmt
);
4789 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4795 /* Basic block BB_COPY was created by code duplication. Add phi node
4796 arguments for edges going out of BB_COPY. The blocks that were
4797 duplicated have rbi->duplicated set to one. */
4800 add_phi_args_after_copy_bb (basic_block bb_copy
)
4802 basic_block bb
, dest
;
4805 tree phi
, phi_copy
, phi_next
, def
;
4807 bb
= bb_copy
->rbi
->original
;
4809 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4811 if (!phi_nodes (e_copy
->dest
))
4814 if (e_copy
->dest
->rbi
->duplicated
)
4815 dest
= e_copy
->dest
->rbi
->original
;
4817 dest
= e_copy
->dest
;
4819 e
= find_edge (bb
, dest
);
4822 /* During loop unrolling the target of the latch edge is copied.
4823 In this case we are not looking for edge to dest, but to
4824 duplicated block whose original was dest. */
4825 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4826 if (e
->dest
->rbi
->duplicated
4827 && e
->dest
->rbi
->original
== dest
)
4830 gcc_assert (e
!= NULL
);
4833 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4835 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4837 phi_next
= PHI_CHAIN (phi
);
4839 gcc_assert (PHI_RESULT (phi
) == PHI_RESULT (phi_copy
));
4840 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4841 add_phi_arg (phi_copy
, def
, e_copy
);
4846 /* Blocks in REGION_COPY array of length N_REGION were created by
4847 duplication of basic blocks. Add phi node arguments for edges
4848 going from these blocks. */
4851 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4855 for (i
= 0; i
< n_region
; i
++)
4856 region_copy
[i
]->rbi
->duplicated
= 1;
4858 for (i
= 0; i
< n_region
; i
++)
4859 add_phi_args_after_copy_bb (region_copy
[i
]);
4861 for (i
= 0; i
< n_region
; i
++)
4862 region_copy
[i
]->rbi
->duplicated
= 0;
4865 /* Maps the old ssa name FROM_NAME to TO_NAME. */
4867 struct ssa_name_map_entry
4873 /* Hash function for ssa_name_map_entry. */
4876 ssa_name_map_entry_hash (const void *entry
)
4878 const struct ssa_name_map_entry
*en
= entry
;
4879 return SSA_NAME_VERSION (en
->from_name
);
4882 /* Equality function for ssa_name_map_entry. */
4885 ssa_name_map_entry_eq (const void *in_table
, const void *ssa_name
)
4887 const struct ssa_name_map_entry
*en
= in_table
;
4889 return en
->from_name
== ssa_name
;
4892 /* Allocate duplicates of ssa names in list DEFINITIONS and store the mapping
4896 allocate_ssa_names (bitmap definitions
, htab_t
*map
)
4899 struct ssa_name_map_entry
*entry
;
4905 *map
= htab_create (10, ssa_name_map_entry_hash
,
4906 ssa_name_map_entry_eq
, free
);
4907 EXECUTE_IF_SET_IN_BITMAP (definitions
, 0, ver
, bi
)
4909 name
= ssa_name (ver
);
4910 slot
= htab_find_slot_with_hash (*map
, name
, SSA_NAME_VERSION (name
),
4916 entry
= xmalloc (sizeof (struct ssa_name_map_entry
));
4917 entry
->from_name
= name
;
4920 entry
->to_name
= duplicate_ssa_name (name
, SSA_NAME_DEF_STMT (name
));
4924 /* Rewrite the definition DEF in statement STMT to new ssa name as specified
4925 by the mapping MAP. */
4928 rewrite_to_new_ssa_names_def (def_operand_p def
, tree stmt
, htab_t map
)
4930 tree name
= DEF_FROM_PTR (def
);
4931 struct ssa_name_map_entry
*entry
;
4933 gcc_assert (TREE_CODE (name
) == SSA_NAME
);
4935 entry
= htab_find_with_hash (map
, name
, SSA_NAME_VERSION (name
));
4939 SET_DEF (def
, entry
->to_name
);
4940 SSA_NAME_DEF_STMT (entry
->to_name
) = stmt
;
4943 /* Rewrite the USE to new ssa name as specified by the mapping MAP. */
4946 rewrite_to_new_ssa_names_use (use_operand_p use
, htab_t map
)
4948 tree name
= USE_FROM_PTR (use
);
4949 struct ssa_name_map_entry
*entry
;
4951 if (TREE_CODE (name
) != SSA_NAME
)
4954 entry
= htab_find_with_hash (map
, name
, SSA_NAME_VERSION (name
));
4958 SET_USE (use
, entry
->to_name
);
4961 /* Rewrite the ssa names in basic block BB to new ones as specified by the
4965 rewrite_to_new_ssa_names_bb (basic_block bb
, htab_t map
)
4971 block_stmt_iterator bsi
;
4975 v_may_def_optype v_may_defs
;
4976 v_must_def_optype v_must_defs
;
4979 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4980 if (e
->flags
& EDGE_ABNORMAL
)
4983 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4985 rewrite_to_new_ssa_names_def (PHI_RESULT_PTR (phi
), phi
, map
);
4987 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi
)) = 1;
4990 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4992 stmt
= bsi_stmt (bsi
);
4993 get_stmt_operands (stmt
);
4994 ann
= stmt_ann (stmt
);
4996 uses
= USE_OPS (ann
);
4997 for (i
= 0; i
< NUM_USES (uses
); i
++)
4998 rewrite_to_new_ssa_names_use (USE_OP_PTR (uses
, i
), map
);
5000 defs
= DEF_OPS (ann
);
5001 for (i
= 0; i
< NUM_DEFS (defs
); i
++)
5002 rewrite_to_new_ssa_names_def (DEF_OP_PTR (defs
, i
), stmt
, map
);
5004 vuses
= VUSE_OPS (ann
);
5005 for (i
= 0; i
< NUM_VUSES (vuses
); i
++)
5006 rewrite_to_new_ssa_names_use (VUSE_OP_PTR (vuses
, i
), map
);
5008 v_may_defs
= V_MAY_DEF_OPS (ann
);
5009 for (i
= 0; i
< NUM_V_MAY_DEFS (v_may_defs
); i
++)
5011 rewrite_to_new_ssa_names_use
5012 (V_MAY_DEF_OP_PTR (v_may_defs
, i
), map
);
5013 rewrite_to_new_ssa_names_def
5014 (V_MAY_DEF_RESULT_PTR (v_may_defs
, i
), stmt
, map
);
5017 v_must_defs
= V_MUST_DEF_OPS (ann
);
5018 for (i
= 0; i
< NUM_V_MUST_DEFS (v_must_defs
); i
++)
5020 rewrite_to_new_ssa_names_def
5021 (V_MUST_DEF_RESULT_PTR (v_must_defs
, i
), stmt
, map
);
5022 rewrite_to_new_ssa_names_use
5023 (V_MUST_DEF_KILL_PTR (v_must_defs
, i
), map
);
5027 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5028 for (phi
= phi_nodes (e
->dest
); phi
; phi
= PHI_CHAIN (phi
))
5030 rewrite_to_new_ssa_names_use
5031 (PHI_ARG_DEF_PTR_FROM_EDGE (phi
, e
), map
);
5033 if (e
->flags
& EDGE_ABNORMAL
)
5035 tree op
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
5036 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
) = 1;
5041 /* Rewrite the ssa names in N_REGION blocks REGION to the new ones as specified
5042 by the mapping MAP. */
5045 rewrite_to_new_ssa_names (basic_block
*region
, unsigned n_region
, htab_t map
)
5049 for (r
= 0; r
< n_region
; r
++)
5050 rewrite_to_new_ssa_names_bb (region
[r
], map
);
5053 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
5054 important exit edge EXIT. By important we mean that no SSA name defined
5055 inside region is live over the other exit edges of the region. All entry
5056 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
5057 to the duplicate of the region. SSA form, dominance and loop information
5058 is updated. The new basic blocks are stored to REGION_COPY in the same
5059 order as they had in REGION, provided that REGION_COPY is not NULL.
5060 The function returns false if it is unable to copy the region,
5064 tree_duplicate_sese_region (edge entry
, edge exit
,
5065 basic_block
*region
, unsigned n_region
,
5066 basic_block
*region_copy
)
5068 unsigned i
, n_doms
, ver
;
5069 bool free_region_copy
= false, copying_header
= false;
5070 struct loop
*loop
= entry
->dest
->loop_father
;
5075 htab_t ssa_name_map
= NULL
;
5079 if (!can_copy_bbs_p (region
, n_region
))
5082 /* Some sanity checking. Note that we do not check for all possible
5083 missuses of the functions. I.e. if you ask to copy something weird,
5084 it will work, but the state of structures probably will not be
5087 for (i
= 0; i
< n_region
; i
++)
5089 /* We do not handle subloops, i.e. all the blocks must belong to the
5091 if (region
[i
]->loop_father
!= loop
)
5094 if (region
[i
] != entry
->dest
5095 && region
[i
] == loop
->header
)
5101 /* In case the function is used for loop header copying (which is the primary
5102 use), ensure that EXIT and its copy will be new latch and entry edges. */
5103 if (loop
->header
== entry
->dest
)
5105 copying_header
= true;
5106 loop
->copy
= loop
->outer
;
5108 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
5111 for (i
= 0; i
< n_region
; i
++)
5112 if (region
[i
] != exit
->src
5113 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
5119 region_copy
= xmalloc (sizeof (basic_block
) * n_region
);
5120 free_region_copy
= true;
5123 gcc_assert (!any_marked_for_rewrite_p ());
5125 /* Record blocks outside the region that are duplicated by something
5127 doms
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
5128 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
5130 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
);
5131 definitions
= marked_ssa_names ();
5135 loop
->header
= exit
->dest
;
5136 loop
->latch
= exit
->src
;
5139 /* Redirect the entry and add the phi node arguments. */
5140 redirected
= redirect_edge_and_branch (entry
, entry
->dest
->rbi
->copy
);
5141 gcc_assert (redirected
!= NULL
);
5142 flush_pending_stmts (entry
);
5144 /* Concerning updating of dominators: We must recount dominators
5145 for entry block and its copy. Anything that is outside of the region, but
5146 was dominated by something inside needs recounting as well. */
5147 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
5148 doms
[n_doms
++] = entry
->dest
->rbi
->original
;
5149 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
5152 /* Add the other phi node arguments. */
5153 add_phi_args_after_copy (region_copy
, n_region
);
5155 /* Add phi nodes for definitions at exit. TODO -- once we have immediate
5156 uses, it should be possible to emit phi nodes just for definitions that
5157 are used outside region. */
5158 EXECUTE_IF_SET_IN_BITMAP (definitions
, 0, ver
, bi
)
5160 tree name
= ssa_name (ver
);
5162 phi
= create_phi_node (name
, exit
->dest
);
5163 add_phi_arg (phi
, name
, exit
);
5164 add_phi_arg (phi
, name
, exit_copy
);
5166 SSA_NAME_DEF_STMT (name
) = phi
;
5169 /* And create new definitions inside region and its copy. TODO -- once we
5170 have immediate uses, it might be better to leave definitions in region
5171 unchanged, create new ssa names for phi nodes on exit, and rewrite
5172 the uses, to avoid changing the copied region. */
5173 allocate_ssa_names (definitions
, &ssa_name_map
);
5174 rewrite_to_new_ssa_names (region
, n_region
, ssa_name_map
);
5175 allocate_ssa_names (definitions
, &ssa_name_map
);
5176 rewrite_to_new_ssa_names (region_copy
, n_region
, ssa_name_map
);
5177 htab_delete (ssa_name_map
);
5179 if (free_region_copy
)
5182 unmark_all_for_rewrite ();
5183 BITMAP_FREE (definitions
);
5188 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5191 dump_function_to_file (tree fn
, FILE *file
, int flags
)
5193 tree arg
, vars
, var
;
5194 bool ignore_topmost_bind
= false, any_var
= false;
5198 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5200 arg
= DECL_ARGUMENTS (fn
);
5203 print_generic_expr (file
, arg
, dump_flags
);
5204 if (TREE_CHAIN (arg
))
5205 fprintf (file
, ", ");
5206 arg
= TREE_CHAIN (arg
);
5208 fprintf (file
, ")\n");
5210 if (flags
& TDF_RAW
)
5212 dump_node (fn
, TDF_SLIM
| flags
, file
);
5216 /* When GIMPLE is lowered, the variables are no longer available in
5217 BIND_EXPRs, so display them separately. */
5218 if (cfun
&& cfun
->unexpanded_var_list
)
5220 ignore_topmost_bind
= true;
5222 fprintf (file
, "{\n");
5223 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5225 var
= TREE_VALUE (vars
);
5227 print_generic_decl (file
, var
, flags
);
5228 fprintf (file
, "\n");
5234 if (basic_block_info
)
5236 /* Make a CFG based dump. */
5237 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5238 if (!ignore_topmost_bind
)
5239 fprintf (file
, "{\n");
5241 if (any_var
&& n_basic_blocks
)
5242 fprintf (file
, "\n");
5245 dump_generic_bb (file
, bb
, 2, flags
);
5247 fprintf (file
, "}\n");
5248 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5254 /* Make a tree based dump. */
5255 chain
= DECL_SAVED_TREE (fn
);
5257 if (TREE_CODE (chain
) == BIND_EXPR
)
5259 if (ignore_topmost_bind
)
5261 chain
= BIND_EXPR_BODY (chain
);
5269 if (!ignore_topmost_bind
)
5270 fprintf (file
, "{\n");
5275 fprintf (file
, "\n");
5277 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5278 if (ignore_topmost_bind
)
5279 fprintf (file
, "}\n");
5282 fprintf (file
, "\n\n");
5286 /* Pretty print of the loops intermediate representation. */
5287 static void print_loop (FILE *, struct loop
*, int);
5288 static void print_pred_bbs (FILE *, basic_block bb
);
5289 static void print_succ_bbs (FILE *, basic_block bb
);
5292 /* Print the predecessors indexes of edge E on FILE. */
5295 print_pred_bbs (FILE *file
, basic_block bb
)
5300 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5301 fprintf (file
, "bb_%d", e
->src
->index
);
5305 /* Print the successors indexes of edge E on FILE. */
5308 print_succ_bbs (FILE *file
, basic_block bb
)
5313 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5314 fprintf (file
, "bb_%d", e
->src
->index
);
5318 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5321 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5329 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5330 memset ((void *) s_indent
, ' ', (size_t) indent
);
5331 s_indent
[indent
] = '\0';
5333 /* Print the loop's header. */
5334 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5336 /* Print the loop's body. */
5337 fprintf (file
, "%s{\n", s_indent
);
5339 if (bb
->loop_father
== loop
)
5341 /* Print the basic_block's header. */
5342 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5343 print_pred_bbs (file
, bb
);
5344 fprintf (file
, "}, succs = {");
5345 print_succ_bbs (file
, bb
);
5346 fprintf (file
, "})\n");
5348 /* Print the basic_block's body. */
5349 fprintf (file
, "%s {\n", s_indent
);
5350 tree_dump_bb (bb
, file
, indent
+ 4);
5351 fprintf (file
, "%s }\n", s_indent
);
5354 print_loop (file
, loop
->inner
, indent
+ 2);
5355 fprintf (file
, "%s}\n", s_indent
);
5356 print_loop (file
, loop
->next
, indent
);
5360 /* Follow a CFG edge from the entry point of the program, and on entry
5361 of a loop, pretty print the loop structure on FILE. */
5364 print_loop_ir (FILE *file
)
5368 bb
= BASIC_BLOCK (0);
5369 if (bb
&& bb
->loop_father
)
5370 print_loop (file
, bb
->loop_father
, 0);
5374 /* Debugging loops structure at tree level. */
5377 debug_loop_ir (void)
5379 print_loop_ir (stderr
);
5383 /* Return true if BB ends with a call, possibly followed by some
5384 instructions that must stay with the call. Return false,
5388 tree_block_ends_with_call_p (basic_block bb
)
5390 block_stmt_iterator bsi
= bsi_last (bb
);
5391 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5395 /* Return true if BB ends with a conditional branch. Return false,
5399 tree_block_ends_with_condjump_p (basic_block bb
)
5401 tree stmt
= tsi_stmt (bsi_last (bb
).tsi
);
5402 return (TREE_CODE (stmt
) == COND_EXPR
);
5406 /* Return true if we need to add fake edge to exit at statement T.
5407 Helper function for tree_flow_call_edges_add. */
5410 need_fake_edge_p (tree t
)
5414 /* NORETURN and LONGJMP calls already have an edge to exit.
5415 CONST and PURE calls do not need one.
5416 We don't currently check for CONST and PURE here, although
5417 it would be a good idea, because those attributes are
5418 figured out from the RTL in mark_constant_function, and
5419 the counter incrementation code from -fprofile-arcs
5420 leads to different results from -fbranch-probabilities. */
5421 call
= get_call_expr_in (t
);
5423 && !(call_expr_flags (call
) & ECF_NORETURN
))
5426 if (TREE_CODE (t
) == ASM_EXPR
5427 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5434 /* Add fake edges to the function exit for any non constant and non
5435 noreturn calls, volatile inline assembly in the bitmap of blocks
5436 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5437 the number of blocks that were split.
5439 The goal is to expose cases in which entering a basic block does
5440 not imply that all subsequent instructions must be executed. */
5443 tree_flow_call_edges_add (sbitmap blocks
)
5446 int blocks_split
= 0;
5447 int last_bb
= last_basic_block
;
5448 bool check_last_block
= false;
5450 if (n_basic_blocks
== 0)
5454 check_last_block
= true;
5456 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5458 /* In the last basic block, before epilogue generation, there will be
5459 a fallthru edge to EXIT. Special care is required if the last insn
5460 of the last basic block is a call because make_edge folds duplicate
5461 edges, which would result in the fallthru edge also being marked
5462 fake, which would result in the fallthru edge being removed by
5463 remove_fake_edges, which would result in an invalid CFG.
5465 Moreover, we can't elide the outgoing fake edge, since the block
5466 profiler needs to take this into account in order to solve the minimal
5467 spanning tree in the case that the call doesn't return.
5469 Handle this by adding a dummy instruction in a new last basic block. */
5470 if (check_last_block
)
5472 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5473 block_stmt_iterator bsi
= bsi_last (bb
);
5475 if (!bsi_end_p (bsi
))
5478 if (need_fake_edge_p (t
))
5482 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5485 bsi_insert_on_edge (e
, build_empty_stmt ());
5486 bsi_commit_edge_inserts ();
5491 /* Now add fake edges to the function exit for any non constant
5492 calls since there is no way that we can determine if they will
5494 for (i
= 0; i
< last_bb
; i
++)
5496 basic_block bb
= BASIC_BLOCK (i
);
5497 block_stmt_iterator bsi
;
5498 tree stmt
, last_stmt
;
5503 if (blocks
&& !TEST_BIT (blocks
, i
))
5506 bsi
= bsi_last (bb
);
5507 if (!bsi_end_p (bsi
))
5509 last_stmt
= bsi_stmt (bsi
);
5512 stmt
= bsi_stmt (bsi
);
5513 if (need_fake_edge_p (stmt
))
5516 /* The handling above of the final block before the
5517 epilogue should be enough to verify that there is
5518 no edge to the exit block in CFG already.
5519 Calling make_edge in such case would cause us to
5520 mark that edge as fake and remove it later. */
5521 #ifdef ENABLE_CHECKING
5522 if (stmt
== last_stmt
)
5524 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5525 gcc_assert (e
== NULL
);
5529 /* Note that the following may create a new basic block
5530 and renumber the existing basic blocks. */
5531 if (stmt
!= last_stmt
)
5533 e
= split_block (bb
, stmt
);
5537 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5541 while (!bsi_end_p (bsi
));
5546 verify_flow_info ();
5548 return blocks_split
;
5552 tree_purge_dead_eh_edges (basic_block bb
)
5554 bool changed
= false;
5557 tree stmt
= last_stmt (bb
);
5559 if (stmt
&& tree_can_throw_internal (stmt
))
5562 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5564 if (e
->flags
& EDGE_EH
)
5573 /* Removal of dead EH edges might change dominators of not
5574 just immediate successors. E.g. when bb1 is changed so that
5575 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5576 eh edges purged by this function in:
5588 idom(bb5) must be recomputed. For now just free the dominance
5591 free_dominance_info (CDI_DOMINATORS
);
5597 tree_purge_all_dead_eh_edges (bitmap blocks
)
5599 bool changed
= false;
5603 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5605 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5611 /* This function is called whenever a new edge is created or
5615 tree_execute_on_growing_pred (edge e
)
5617 basic_block bb
= e
->dest
;
5620 reserve_phi_args_for_new_edge (bb
);
5623 /* This function is called immediately before edge E is removed from
5624 the edge vector E->dest->preds. */
5627 tree_execute_on_shrinking_pred (edge e
)
5629 if (phi_nodes (e
->dest
))
5630 remove_phi_args (e
);
5633 struct cfg_hooks tree_cfg_hooks
= {
5635 tree_verify_flow_info
,
5636 tree_dump_bb
, /* dump_bb */
5637 create_bb
, /* create_basic_block */
5638 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5639 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5640 remove_bb
, /* delete_basic_block */
5641 tree_split_block
, /* split_block */
5642 tree_move_block_after
, /* move_block_after */
5643 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5644 tree_merge_blocks
, /* merge_blocks */
5645 tree_predict_edge
, /* predict_edge */
5646 tree_predicted_by_p
, /* predicted_by_p */
5647 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5648 tree_duplicate_bb
, /* duplicate_block */
5649 tree_split_edge
, /* split_edge */
5650 tree_make_forwarder_block
, /* make_forward_block */
5651 NULL
, /* tidy_fallthru_edge */
5652 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5653 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5654 tree_flow_call_edges_add
, /* flow_call_edges_add */
5655 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5656 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5660 /* Split all critical edges. */
5663 split_critical_edges (void)
5669 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5670 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5671 mappings around the calls to split_edge. */
5672 start_recording_case_labels ();
5675 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5676 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5681 end_recording_case_labels ();
5684 struct tree_opt_pass pass_split_crit_edges
=
5686 "crited", /* name */
5688 split_critical_edges
, /* execute */
5691 0, /* static_pass_number */
5692 TV_TREE_SPLIT_EDGES
, /* tv_id */
5693 PROP_cfg
, /* properties required */
5694 PROP_no_crit_edges
, /* properties_provided */
5695 0, /* properties_destroyed */
5696 0, /* todo_flags_start */
5697 TODO_dump_func
, /* todo_flags_finish */
5702 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5703 a temporary, make sure and register it to be renamed if necessary,
5704 and finally return the temporary. Put the statements to compute
5705 EXP before the current statement in BSI. */
5708 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5710 tree t
, new_stmt
, orig_stmt
;
5712 if (is_gimple_val (exp
))
5715 t
= make_rename_temp (type
, NULL
);
5716 new_stmt
= build (MODIFY_EXPR
, type
, t
, exp
);
5718 orig_stmt
= bsi_stmt (*bsi
);
5719 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5720 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5722 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5727 /* Build a ternary operation and gimplify it. Emit code before BSI.
5728 Return the gimple_val holding the result. */
5731 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5732 tree type
, tree a
, tree b
, tree c
)
5736 ret
= fold (build3 (code
, type
, a
, b
, c
));
5739 return gimplify_val (bsi
, type
, ret
);
5742 /* Build a binary operation and gimplify it. Emit code before BSI.
5743 Return the gimple_val holding the result. */
5746 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5747 tree type
, tree a
, tree b
)
5751 ret
= fold (build2 (code
, type
, a
, b
));
5754 return gimplify_val (bsi
, type
, ret
);
5757 /* Build a unary operation and gimplify it. Emit code before BSI.
5758 Return the gimple_val holding the result. */
5761 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5766 ret
= fold (build1 (code
, type
, a
));
5769 return gimplify_val (bsi
, type
, ret
);
5774 /* Emit return warnings. */
5777 execute_warn_function_return (void)
5779 #ifdef USE_MAPPED_LOCATION
5780 source_location location
;
5788 if (warn_missing_noreturn
5789 && !TREE_THIS_VOLATILE (cfun
->decl
)
5790 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5791 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5792 warning ("%Jfunction might be possible candidate for "
5793 "attribute %<noreturn%>",
5796 /* If we have a path to EXIT, then we do return. */
5797 if (TREE_THIS_VOLATILE (cfun
->decl
)
5798 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5800 #ifdef USE_MAPPED_LOCATION
5801 location
= UNKNOWN_LOCATION
;
5805 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5807 last
= last_stmt (e
->src
);
5808 if (TREE_CODE (last
) == RETURN_EXPR
5809 #ifdef USE_MAPPED_LOCATION
5810 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5812 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5816 #ifdef USE_MAPPED_LOCATION
5817 if (location
== UNKNOWN_LOCATION
)
5818 location
= cfun
->function_end_locus
;
5819 warning ("%H%<noreturn%> function does return", &location
);
5822 locus
= &cfun
->function_end_locus
;
5823 warning ("%H%<noreturn%> function does return", locus
);
5827 /* If we see "return;" in some basic block, then we do reach the end
5828 without returning a value. */
5829 else if (warn_return_type
5830 && !TREE_NO_WARNING (cfun
->decl
)
5831 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5832 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5834 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5836 tree last
= last_stmt (e
->src
);
5837 if (TREE_CODE (last
) == RETURN_EXPR
5838 && TREE_OPERAND (last
, 0) == NULL
)
5840 #ifdef USE_MAPPED_LOCATION
5841 location
= EXPR_LOCATION (last
);
5842 if (location
== UNKNOWN_LOCATION
)
5843 location
= cfun
->function_end_locus
;
5844 warning ("%Hcontrol reaches end of non-void function", &location
);
5846 locus
= EXPR_LOCUS (last
);
5848 locus
= &cfun
->function_end_locus
;
5849 warning ("%Hcontrol reaches end of non-void function", locus
);
5851 TREE_NO_WARNING (cfun
->decl
) = 1;
5859 /* Given a basic block B which ends with a conditional and has
5860 precisely two successors, determine which of the edges is taken if
5861 the conditional is true and which is taken if the conditional is
5862 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5865 extract_true_false_edges_from_block (basic_block b
,
5869 edge e
= EDGE_SUCC (b
, 0);
5871 if (e
->flags
& EDGE_TRUE_VALUE
)
5874 *false_edge
= EDGE_SUCC (b
, 1);
5879 *true_edge
= EDGE_SUCC (b
, 1);
5883 struct tree_opt_pass pass_warn_function_return
=
5887 execute_warn_function_return
, /* execute */
5890 0, /* static_pass_number */
5892 PROP_cfg
, /* properties_required */
5893 0, /* properties_provided */
5894 0, /* properties_destroyed */
5895 0, /* todo_flags_start */
5896 0, /* todo_flags_finish */
5900 #include "gt-tree-cfg.h"