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, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
36 #include "langhooks.h"
37 #include "diagnostic.h"
38 #include "tree-flow.h"
40 #include "tree-dump.h"
41 #include "tree-pass.h"
45 #include "cfglayout.h"
47 #include "tree-ssa-propagate.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 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
58 which use a particular edge. The CASE_LABEL_EXPRs are chained together
59 via their TREE_CHAIN field, which we clear after we're done with the
60 hash table to prevent problems with duplication of SWITCH_EXPRs.
62 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
63 update the case vector in response to edge redirections.
65 Right now this table is set up and torn down at key points in the
66 compilation process. It would be nice if we could make the table
67 more persistent. The key is getting notification of changes to
68 the CFG (particularly edge removal, creation and redirection). */
70 struct edge_to_cases_elt
72 /* The edge itself. Necessary for hashing and equality tests. */
75 /* The case labels associated with this edge. We link these up via
76 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
77 when we destroy the hash table. This prevents problems when copying
82 static htab_t edge_to_cases
;
87 long num_merged_labels
;
90 static struct cfg_stats_d cfg_stats
;
92 /* Nonzero if we found a computed goto while building basic blocks. */
93 static bool found_computed_goto
;
95 /* Basic blocks and flowgraphs. */
96 static basic_block
create_bb (void *, void *, basic_block
);
97 static void make_blocks (tree
);
98 static void factor_computed_gotos (void);
101 static void make_edges (void);
102 static void make_ctrl_stmt_edges (basic_block
);
103 static void make_exit_edges (basic_block
);
104 static void make_cond_expr_edges (basic_block
);
105 static void make_switch_expr_edges (basic_block
);
106 static void make_goto_expr_edges (basic_block
);
107 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
108 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
109 static void split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree
, tree
);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge
);
115 static void tree_cfg2vcg (FILE *);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block
, basic_block
);
119 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
120 static void remove_bb (basic_block
);
121 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
122 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
123 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
124 static tree
find_case_label_for_value (tree
, tree
);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status
= PROFILE_ABSENT
;
133 last_basic_block
= 0;
134 VARRAY_BB_INIT (basic_block_info
, initial_cfg_capacity
, "basic_block_info");
136 /* Build a mapping of labels to their associated blocks. */
137 VARRAY_BB_INIT (label_to_block_map
, initial_cfg_capacity
,
138 "label to block map");
140 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
141 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
144 /*---------------------------------------------------------------------------
146 ---------------------------------------------------------------------------*/
148 /* Entry point to the CFG builder for trees. TP points to the list of
149 statements to be added to the flowgraph. */
152 build_tree_cfg (tree
*tp
)
154 /* Register specific tree functions. */
155 tree_register_cfg_hooks ();
157 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
159 init_empty_tree_cfg ();
161 found_computed_goto
= 0;
164 /* Computed gotos are hell to deal with, especially if there are
165 lots of them with a large number of destinations. So we factor
166 them to a common computed goto location before we build the
167 edge list. After we convert back to normal form, we will un-factor
168 the computed gotos since factoring introduces an unwanted jump. */
169 if (found_computed_goto
)
170 factor_computed_gotos ();
172 /* Make sure there is always at least one block, even if it's empty. */
173 if (n_basic_blocks
== 0)
174 create_empty_bb (ENTRY_BLOCK_PTR
);
176 /* Adjust the size of the array. */
177 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
179 /* To speed up statement iterator walks, we first purge dead labels. */
180 cleanup_dead_labels ();
182 /* Group case nodes to reduce the number of edges.
183 We do this after cleaning up dead labels because otherwise we miss
184 a lot of obvious case merging opportunities. */
185 group_case_labels ();
187 /* Create the edges of the flowgraph. */
190 /* Debugging dumps. */
192 /* Write the flowgraph to a VCG file. */
194 int local_dump_flags
;
195 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
198 tree_cfg2vcg (dump_file
);
199 dump_end (TDI_vcg
, dump_file
);
203 #ifdef ENABLE_CHECKING
207 /* Dump a textual representation of the flowgraph. */
209 dump_tree_cfg (dump_file
, dump_flags
);
213 execute_build_cfg (void)
215 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
218 struct tree_opt_pass pass_build_cfg
=
222 execute_build_cfg
, /* execute */
225 0, /* static_pass_number */
226 TV_TREE_CFG
, /* tv_id */
227 PROP_gimple_leh
, /* properties_required */
228 PROP_cfg
, /* properties_provided */
229 0, /* properties_destroyed */
230 0, /* todo_flags_start */
231 TODO_verify_stmts
, /* todo_flags_finish */
235 /* Search the CFG for any computed gotos. If found, factor them to a
236 common computed goto site. Also record the location of that site so
237 that we can un-factor the gotos after we have converted back to
241 factor_computed_gotos (void)
244 tree factored_label_decl
= NULL
;
246 tree factored_computed_goto_label
= NULL
;
247 tree factored_computed_goto
= NULL
;
249 /* We know there are one or more computed gotos in this function.
250 Examine the last statement in each basic block to see if the block
251 ends with a computed goto. */
255 block_stmt_iterator bsi
= bsi_last (bb
);
260 last
= bsi_stmt (bsi
);
262 /* Ignore the computed goto we create when we factor the original
264 if (last
== factored_computed_goto
)
267 /* If the last statement is a computed goto, factor it. */
268 if (computed_goto_p (last
))
272 /* The first time we find a computed goto we need to create
273 the factored goto block and the variable each original
274 computed goto will use for their goto destination. */
275 if (! factored_computed_goto
)
277 basic_block new_bb
= create_empty_bb (bb
);
278 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
280 /* Create the destination of the factored goto. Each original
281 computed goto will put its desired destination into this
282 variable and jump to the label we create immediately
284 var
= create_tmp_var (ptr_type_node
, "gotovar");
286 /* Build a label for the new block which will contain the
287 factored computed goto. */
288 factored_label_decl
= create_artificial_label ();
289 factored_computed_goto_label
290 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
291 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
294 /* Build our new computed goto. */
295 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
296 bsi_insert_after (&new_bsi
, factored_computed_goto
,
300 /* Copy the original computed goto's destination into VAR. */
301 assignment
= build (MODIFY_EXPR
, ptr_type_node
,
302 var
, GOTO_DESTINATION (last
));
303 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
305 /* And re-vector the computed goto to the new destination. */
306 GOTO_DESTINATION (last
) = factored_label_decl
;
312 /* Build a flowgraph for the statement_list STMT_LIST. */
315 make_blocks (tree stmt_list
)
317 tree_stmt_iterator i
= tsi_start (stmt_list
);
319 bool start_new_block
= true;
320 bool first_stmt_of_list
= true;
321 basic_block bb
= ENTRY_BLOCK_PTR
;
323 while (!tsi_end_p (i
))
330 /* If the statement starts a new basic block or if we have determined
331 in a previous pass that we need to create a new block for STMT, do
333 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
335 if (!first_stmt_of_list
)
336 stmt_list
= tsi_split_statement_list_before (&i
);
337 bb
= create_basic_block (stmt_list
, NULL
, bb
);
338 start_new_block
= false;
341 /* Now add STMT to BB and create the subgraphs for special statement
343 set_bb_for_stmt (stmt
, bb
);
345 if (computed_goto_p (stmt
))
346 found_computed_goto
= true;
348 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
350 if (stmt_ends_bb_p (stmt
))
351 start_new_block
= true;
354 first_stmt_of_list
= false;
359 /* Create and return a new empty basic block after bb AFTER. */
362 create_bb (void *h
, void *e
, basic_block after
)
368 /* Create and initialize a new basic block. Since alloc_block uses
369 ggc_alloc_cleared to allocate a basic block, we do not have to
370 clear the newly allocated basic block here. */
373 bb
->index
= last_basic_block
;
375 bb
->stmt_list
= h
? h
: alloc_stmt_list ();
377 /* Add the new block to the linked list of blocks. */
378 link_block (bb
, after
);
380 /* Grow the basic block array if needed. */
381 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
383 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
384 VARRAY_GROW (basic_block_info
, new_size
);
387 /* Add the newly created block to the array. */
388 BASIC_BLOCK (last_basic_block
) = bb
;
397 /*---------------------------------------------------------------------------
399 ---------------------------------------------------------------------------*/
401 /* Fold COND_EXPR_COND of each COND_EXPR. */
404 fold_cond_expr_cond (void)
410 tree stmt
= last_stmt (bb
);
413 && TREE_CODE (stmt
) == COND_EXPR
)
415 tree cond
= fold (COND_EXPR_COND (stmt
));
416 if (integer_zerop (cond
))
417 COND_EXPR_COND (stmt
) = boolean_false_node
;
418 else if (integer_onep (cond
))
419 COND_EXPR_COND (stmt
) = boolean_true_node
;
424 /* Join all the blocks in the flowgraph. */
431 /* Create an edge from entry to the first block with executable
433 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (0), EDGE_FALLTHRU
);
435 /* Traverse the basic block array placing edges. */
438 tree first
= first_stmt (bb
);
439 tree last
= last_stmt (bb
);
443 /* Edges for statements that always alter flow control. */
444 if (is_ctrl_stmt (last
))
445 make_ctrl_stmt_edges (bb
);
447 /* Edges for statements that sometimes alter flow control. */
448 if (is_ctrl_altering_stmt (last
))
449 make_exit_edges (bb
);
452 /* Finally, if no edges were created above, this is a regular
453 basic block that only needs a fallthru edge. */
454 if (EDGE_COUNT (bb
->succs
) == 0)
455 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
458 /* We do not care about fake edges, so remove any that the CFG
459 builder inserted for completeness. */
460 remove_fake_exit_edges ();
462 /* Fold COND_EXPR_COND of each COND_EXPR. */
463 fold_cond_expr_cond ();
465 /* Clean up the graph and warn for unreachable code. */
470 /* Create edges for control statement at basic block BB. */
473 make_ctrl_stmt_edges (basic_block bb
)
475 tree last
= last_stmt (bb
);
478 switch (TREE_CODE (last
))
481 make_goto_expr_edges (bb
);
485 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
489 make_cond_expr_edges (bb
);
493 make_switch_expr_edges (bb
);
497 make_eh_edges (last
);
498 /* Yet another NORETURN hack. */
499 if (EDGE_COUNT (bb
->succs
) == 0)
500 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
509 /* Create exit edges for statements in block BB that alter the flow of
510 control. Statements that alter the control flow are 'goto', 'return'
511 and calls to non-returning functions. */
514 make_exit_edges (basic_block bb
)
516 tree last
= last_stmt (bb
), op
;
519 switch (TREE_CODE (last
))
524 /* If this function receives a nonlocal goto, then we need to
525 make edges from this call site to all the nonlocal goto
527 if (TREE_SIDE_EFFECTS (last
)
528 && current_function_has_nonlocal_label
)
529 make_goto_expr_edges (bb
);
531 /* If this statement has reachable exception handlers, then
532 create abnormal edges to them. */
533 make_eh_edges (last
);
535 /* Some calls are known not to return. For such calls we create
538 We really need to revamp how we build edges so that it's not
539 such a bloody pain to avoid creating edges for this case since
540 all we do is remove these edges when we're done building the
542 if (call_expr_flags (last
) & ECF_NORETURN
)
544 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
548 /* Don't forget the fall-thru edge. */
549 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
553 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
554 may have an abnormal edge. Search the RHS for this case and
555 create any required edges. */
556 op
= get_call_expr_in (last
);
557 if (op
&& TREE_SIDE_EFFECTS (op
)
558 && current_function_has_nonlocal_label
)
559 make_goto_expr_edges (bb
);
561 make_eh_edges (last
);
562 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
571 /* Create the edges for a COND_EXPR starting at block BB.
572 At this point, both clauses must contain only simple gotos. */
575 make_cond_expr_edges (basic_block bb
)
577 tree entry
= last_stmt (bb
);
578 basic_block then_bb
, else_bb
;
579 tree then_label
, else_label
;
582 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
584 /* Entry basic blocks for each component. */
585 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
586 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
587 then_bb
= label_to_block (then_label
);
588 else_bb
= label_to_block (else_label
);
590 make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
591 make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
594 /* Hashing routine for EDGE_TO_CASES. */
597 edge_to_cases_hash (const void *p
)
599 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
601 /* Hash on the edge itself (which is a pointer). */
602 return htab_hash_pointer (e
);
605 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
606 for equality is just a pointer comparison. */
609 edge_to_cases_eq (const void *p1
, const void *p2
)
611 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
612 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
617 /* Called for each element in the hash table (P) as we delete the
618 edge to cases hash table.
620 Clear all the TREE_CHAINs to prevent problems with copying of
621 SWITCH_EXPRs and structure sharing rules, then free the hash table
625 edge_to_cases_cleanup (void *p
)
627 struct edge_to_cases_elt
*elt
= p
;
630 for (t
= elt
->case_labels
; t
; t
= next
)
632 next
= TREE_CHAIN (t
);
633 TREE_CHAIN (t
) = NULL
;
638 /* Start recording information mapping edges to case labels. */
641 start_recording_case_labels (void)
643 gcc_assert (edge_to_cases
== NULL
);
645 edge_to_cases
= htab_create (37,
648 edge_to_cases_cleanup
);
651 /* Return nonzero if we are recording information for case labels. */
654 recording_case_labels_p (void)
656 return (edge_to_cases
!= NULL
);
659 /* Stop recording information mapping edges to case labels and
660 remove any information we have recorded. */
662 end_recording_case_labels (void)
664 htab_delete (edge_to_cases
);
665 edge_to_cases
= NULL
;
668 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
671 record_switch_edge (edge e
, tree case_label
)
673 struct edge_to_cases_elt
*elt
;
676 /* Build a hash table element so we can see if E is already
678 elt
= xmalloc (sizeof (struct edge_to_cases_elt
));
680 elt
->case_labels
= case_label
;
682 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
686 /* E was not in the hash table. Install E into the hash table. */
691 /* E was already in the hash table. Free ELT as we do not need it
695 /* Get the entry stored in the hash table. */
696 elt
= (struct edge_to_cases_elt
*) *slot
;
698 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
699 TREE_CHAIN (case_label
) = elt
->case_labels
;
700 elt
->case_labels
= case_label
;
704 /* If we are inside a {start,end}_recording_cases block, then return
705 a chain of CASE_LABEL_EXPRs from T which reference E.
707 Otherwise return NULL. */
710 get_cases_for_edge (edge e
, tree t
)
712 struct edge_to_cases_elt elt
, *elt_p
;
717 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
718 chains available. Return NULL so the caller can detect this case. */
719 if (!recording_case_labels_p ())
724 elt
.case_labels
= NULL
;
725 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
729 elt_p
= (struct edge_to_cases_elt
*)*slot
;
730 return elt_p
->case_labels
;
733 /* If we did not find E in the hash table, then this must be the first
734 time we have been queried for information about E & T. Add all the
735 elements from T to the hash table then perform the query again. */
737 vec
= SWITCH_LABELS (t
);
738 n
= TREE_VEC_LENGTH (vec
);
739 for (i
= 0; i
< n
; i
++)
741 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
742 basic_block label_bb
= label_to_block (lab
);
743 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
748 /* Create the edges for a SWITCH_EXPR starting at block BB.
749 At this point, the switch body has been lowered and the
750 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
753 make_switch_expr_edges (basic_block bb
)
755 tree entry
= last_stmt (bb
);
759 vec
= SWITCH_LABELS (entry
);
760 n
= TREE_VEC_LENGTH (vec
);
762 for (i
= 0; i
< n
; ++i
)
764 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
765 basic_block label_bb
= label_to_block (lab
);
766 make_edge (bb
, label_bb
, 0);
771 /* Return the basic block holding label DEST. */
774 label_to_block_fn (struct function
*ifun
, tree dest
)
776 int uid
= LABEL_DECL_UID (dest
);
778 /* We would die hard when faced by an undefined label. Emit a label to
779 the very first basic block. This will hopefully make even the dataflow
780 and undefined variable warnings quite right. */
781 if ((errorcount
|| sorrycount
) && uid
< 0)
783 block_stmt_iterator bsi
= bsi_start (BASIC_BLOCK (0));
786 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
787 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
788 uid
= LABEL_DECL_UID (dest
);
790 if (VARRAY_SIZE (ifun
->cfg
->x_label_to_block_map
) <= (unsigned int)uid
)
792 return VARRAY_BB (ifun
->cfg
->x_label_to_block_map
, uid
);
795 /* Create edges for a goto statement at block BB. */
798 make_goto_expr_edges (basic_block bb
)
801 basic_block target_bb
;
803 block_stmt_iterator last
= bsi_last (bb
);
805 goto_t
= bsi_stmt (last
);
807 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
808 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
809 from a nonlocal goto. */
810 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
814 tree dest
= GOTO_DESTINATION (goto_t
);
817 /* A GOTO to a local label creates normal edges. */
818 if (simple_goto_p (goto_t
))
820 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
821 #ifdef USE_MAPPED_LOCATION
822 e
->goto_locus
= EXPR_LOCATION (goto_t
);
824 e
->goto_locus
= EXPR_LOCUS (goto_t
);
830 /* Nothing more to do for nonlocal gotos. */
831 if (TREE_CODE (dest
) == LABEL_DECL
)
834 /* Computed gotos remain. */
837 /* Look for the block starting with the destination label. In the
838 case of a computed goto, make an edge to any label block we find
840 FOR_EACH_BB (target_bb
)
842 block_stmt_iterator bsi
;
844 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
846 tree target
= bsi_stmt (bsi
);
848 if (TREE_CODE (target
) != LABEL_EXPR
)
852 /* Computed GOTOs. Make an edge to every label block that has
853 been marked as a potential target for a computed goto. */
854 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
855 /* Nonlocal GOTO target. Make an edge to every label block
856 that has been marked as a potential target for a nonlocal
858 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
860 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
866 /* Degenerate case of computed goto with no labels. */
867 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
868 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
872 /*---------------------------------------------------------------------------
874 ---------------------------------------------------------------------------*/
876 /* Cleanup useless labels in basic blocks. This is something we wish
877 to do early because it allows us to group case labels before creating
878 the edges for the CFG, and it speeds up block statement iterators in
880 We only run this pass once, running it more than once is probably not
883 /* A map from basic block index to the leading label of that block. */
884 static tree
*label_for_bb
;
886 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
888 update_eh_label (struct eh_region
*region
)
890 tree old_label
= get_eh_region_tree_label (region
);
894 basic_block bb
= label_to_block (old_label
);
896 /* ??? After optimizing, there may be EH regions with labels
897 that have already been removed from the function body, so
898 there is no basic block for them. */
902 new_label
= label_for_bb
[bb
->index
];
903 set_eh_region_tree_label (region
, new_label
);
907 /* Given LABEL return the first label in the same basic block. */
909 main_block_label (tree label
)
911 basic_block bb
= label_to_block (label
);
913 /* label_to_block possibly inserted undefined label into the chain. */
914 if (!label_for_bb
[bb
->index
])
915 label_for_bb
[bb
->index
] = label
;
916 return label_for_bb
[bb
->index
];
919 /* Cleanup redundant labels. This is a three-step process:
920 1) Find the leading label for each block.
921 2) Redirect all references to labels to the leading labels.
922 3) Cleanup all useless labels. */
925 cleanup_dead_labels (void)
928 label_for_bb
= xcalloc (last_basic_block
, sizeof (tree
));
930 /* Find a suitable label for each block. We use the first user-defined
931 label if there is one, or otherwise just the first label we see. */
934 block_stmt_iterator i
;
936 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
938 tree label
, stmt
= bsi_stmt (i
);
940 if (TREE_CODE (stmt
) != LABEL_EXPR
)
943 label
= LABEL_EXPR_LABEL (stmt
);
945 /* If we have not yet seen a label for the current block,
946 remember this one and see if there are more labels. */
947 if (! label_for_bb
[bb
->index
])
949 label_for_bb
[bb
->index
] = label
;
953 /* If we did see a label for the current block already, but it
954 is an artificially created label, replace it if the current
955 label is a user defined label. */
956 if (! DECL_ARTIFICIAL (label
)
957 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
959 label_for_bb
[bb
->index
] = label
;
965 /* Now redirect all jumps/branches to the selected label.
966 First do so for each block ending in a control statement. */
969 tree stmt
= last_stmt (bb
);
973 switch (TREE_CODE (stmt
))
977 tree true_branch
, false_branch
;
979 true_branch
= COND_EXPR_THEN (stmt
);
980 false_branch
= COND_EXPR_ELSE (stmt
);
982 GOTO_DESTINATION (true_branch
)
983 = main_block_label (GOTO_DESTINATION (true_branch
));
984 GOTO_DESTINATION (false_branch
)
985 = main_block_label (GOTO_DESTINATION (false_branch
));
993 tree vec
= SWITCH_LABELS (stmt
);
994 size_t n
= TREE_VEC_LENGTH (vec
);
996 /* Replace all destination labels. */
997 for (i
= 0; i
< n
; ++i
)
999 tree elt
= TREE_VEC_ELT (vec
, i
);
1000 tree label
= main_block_label (CASE_LABEL (elt
));
1001 CASE_LABEL (elt
) = label
;
1006 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1007 remove them until after we've created the CFG edges. */
1009 if (! computed_goto_p (stmt
))
1011 GOTO_DESTINATION (stmt
)
1012 = main_block_label (GOTO_DESTINATION (stmt
));
1021 for_each_eh_region (update_eh_label
);
1023 /* Finally, purge dead labels. All user-defined labels and labels that
1024 can be the target of non-local gotos are preserved. */
1027 block_stmt_iterator i
;
1028 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1030 if (! label_for_this_bb
)
1033 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1035 tree label
, stmt
= bsi_stmt (i
);
1037 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1040 label
= LABEL_EXPR_LABEL (stmt
);
1042 if (label
== label_for_this_bb
1043 || ! DECL_ARTIFICIAL (label
)
1044 || DECL_NONLOCAL (label
))
1051 free (label_for_bb
);
1054 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1055 and scan the sorted vector of cases. Combine the ones jumping to the
1057 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1060 group_case_labels (void)
1066 tree stmt
= last_stmt (bb
);
1067 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1069 tree labels
= SWITCH_LABELS (stmt
);
1070 int old_size
= TREE_VEC_LENGTH (labels
);
1071 int i
, j
, new_size
= old_size
;
1072 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1075 /* The default label is always the last case in a switch
1076 statement after gimplification. */
1077 default_label
= CASE_LABEL (default_case
);
1079 /* Look for possible opportunities to merge cases.
1080 Ignore the last element of the label vector because it
1081 must be the default case. */
1083 while (i
< old_size
- 1)
1085 tree base_case
, base_label
, base_high
;
1086 base_case
= TREE_VEC_ELT (labels
, i
);
1088 gcc_assert (base_case
);
1089 base_label
= CASE_LABEL (base_case
);
1091 /* Discard cases that have the same destination as the
1093 if (base_label
== default_label
)
1095 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1101 base_high
= CASE_HIGH (base_case
) ?
1102 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1104 /* Try to merge case labels. Break out when we reach the end
1105 of the label vector or when we cannot merge the next case
1106 label with the current one. */
1107 while (i
< old_size
- 1)
1109 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1110 tree merge_label
= CASE_LABEL (merge_case
);
1111 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1112 integer_one_node
, 1);
1114 /* Merge the cases if they jump to the same place,
1115 and their ranges are consecutive. */
1116 if (merge_label
== base_label
1117 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1119 base_high
= CASE_HIGH (merge_case
) ?
1120 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1121 CASE_HIGH (base_case
) = base_high
;
1122 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1131 /* Compress the case labels in the label vector, and adjust the
1132 length of the vector. */
1133 for (i
= 0, j
= 0; i
< new_size
; i
++)
1135 while (! TREE_VEC_ELT (labels
, j
))
1137 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1139 TREE_VEC_LENGTH (labels
) = new_size
;
1144 /* Checks whether we can merge block B into block A. */
1147 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1150 block_stmt_iterator bsi
;
1153 if (!single_succ_p (a
))
1156 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1159 if (single_succ (a
) != b
)
1162 if (!single_pred_p (b
))
1165 if (b
== EXIT_BLOCK_PTR
)
1168 /* If A ends by a statement causing exceptions or something similar, we
1169 cannot merge the blocks. */
1170 stmt
= last_stmt (a
);
1171 if (stmt
&& stmt_ends_bb_p (stmt
))
1174 /* Do not allow a block with only a non-local label to be merged. */
1175 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1176 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1179 /* It must be possible to eliminate all phi nodes in B. If ssa form
1180 is not up-to-date, we cannot eliminate any phis. */
1181 phi
= phi_nodes (b
);
1184 if (need_ssa_update_p ())
1187 for (; phi
; phi
= PHI_CHAIN (phi
))
1188 if (!is_gimple_reg (PHI_RESULT (phi
))
1189 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1193 /* Do not remove user labels. */
1194 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1196 stmt
= bsi_stmt (bsi
);
1197 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1199 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1203 /* Protect the loop latches. */
1205 && b
->loop_father
->latch
== b
)
1211 /* Replaces all uses of NAME by VAL. */
1214 replace_uses_by (tree name
, tree val
)
1216 imm_use_iterator imm_iter
;
1221 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1223 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1225 stmt
= USE_STMT (use
);
1229 if (TREE_CODE (stmt
) == PHI_NODE
)
1231 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1232 if (e
->flags
& EDGE_ABNORMAL
)
1234 /* This can only occur for virtual operands, since
1235 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1236 would prevent replacement. */
1237 gcc_assert (!is_gimple_reg (name
));
1238 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1242 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1245 /* We do not update the statements in the loop above. Consider
1248 If we performed the update in the first loop, the statement
1249 would be rescanned after first occurrence of w is replaced,
1250 the new uses would be placed to the beginning of the list,
1251 and we would never process them. */
1252 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1256 fold_stmt_inplace (stmt
);
1258 rhs
= get_rhs (stmt
);
1259 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1260 recompute_tree_invarant_for_addr_expr (rhs
);
1265 VEC_free (tree
, heap
, stmts
);
1267 /* Also update the trees stored in loop structures. */
1272 for (i
= 0; i
< current_loops
->num
; i
++)
1274 loop
= current_loops
->parray
[i
];
1276 substitute_in_loop_info (loop
, name
, val
);
1281 /* Merge block B into block A. */
1284 tree_merge_blocks (basic_block a
, basic_block b
)
1286 block_stmt_iterator bsi
;
1287 tree_stmt_iterator last
;
1291 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1293 /* Remove the phi nodes. */
1295 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1297 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1300 if (!may_propagate_copy (def
, use
)
1301 /* Propagating pointers might cause the set of vops for statements
1302 to be changed, and thus require ssa form update. */
1303 || (is_gimple_reg (def
)
1304 && POINTER_TYPE_P (TREE_TYPE (def
))))
1306 gcc_assert (is_gimple_reg (def
));
1308 /* Note that just emitting the copies is fine -- there is no problem
1309 with ordering of phi nodes. This is because A is the single
1310 predecessor of B, therefore results of the phi nodes cannot
1311 appear as arguments of the phi nodes. */
1312 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1313 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1314 SET_PHI_RESULT (phi
, NULL_TREE
);
1315 SSA_NAME_DEF_STMT (def
) = copy
;
1318 replace_uses_by (def
, use
);
1319 remove_phi_node (phi
, NULL
);
1322 /* Ensure that B follows A. */
1323 move_block_after (b
, a
);
1325 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1326 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1328 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1329 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1331 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1333 tree label
= bsi_stmt (bsi
);
1336 /* Now that we can thread computed gotos, we might have
1337 a situation where we have a forced label in block B
1338 However, the label at the start of block B might still be
1339 used in other ways (think about the runtime checking for
1340 Fortran assigned gotos). So we can not just delete the
1341 label. Instead we move the label to the start of block A. */
1342 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1344 block_stmt_iterator dest_bsi
= bsi_start (a
);
1345 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1350 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1355 /* Merge the chains. */
1356 last
= tsi_last (a
->stmt_list
);
1357 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1358 b
->stmt_list
= NULL
;
1362 /* Walk the function tree removing unnecessary statements.
1364 * Empty statement nodes are removed
1366 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1368 * Unnecessary COND_EXPRs are removed
1370 * Some unnecessary BIND_EXPRs are removed
1372 Clearly more work could be done. The trick is doing the analysis
1373 and removal fast enough to be a net improvement in compile times.
1375 Note that when we remove a control structure such as a COND_EXPR
1376 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1377 to ensure we eliminate all the useless code. */
1388 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1391 remove_useless_stmts_warn_notreached (tree stmt
)
1393 if (EXPR_HAS_LOCATION (stmt
))
1395 location_t loc
= EXPR_LOCATION (stmt
);
1396 if (LOCATION_LINE (loc
) > 0)
1398 warning (0, "%Hwill never be executed", &loc
);
1403 switch (TREE_CODE (stmt
))
1405 case STATEMENT_LIST
:
1407 tree_stmt_iterator i
;
1408 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1409 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1415 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1417 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1419 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1423 case TRY_FINALLY_EXPR
:
1424 case TRY_CATCH_EXPR
:
1425 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1427 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1432 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1433 case EH_FILTER_EXPR
:
1434 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1436 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1439 /* Not a live container. */
1447 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1449 tree then_clause
, else_clause
, cond
;
1450 bool save_has_label
, then_has_label
, else_has_label
;
1452 save_has_label
= data
->has_label
;
1453 data
->has_label
= false;
1454 data
->last_goto
= NULL
;
1456 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1458 then_has_label
= data
->has_label
;
1459 data
->has_label
= false;
1460 data
->last_goto
= NULL
;
1462 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1464 else_has_label
= data
->has_label
;
1465 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1467 then_clause
= COND_EXPR_THEN (*stmt_p
);
1468 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1469 cond
= fold (COND_EXPR_COND (*stmt_p
));
1471 /* If neither arm does anything at all, we can remove the whole IF. */
1472 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1474 *stmt_p
= build_empty_stmt ();
1475 data
->repeat
= true;
1478 /* If there are no reachable statements in an arm, then we can
1479 zap the entire conditional. */
1480 else if (integer_nonzerop (cond
) && !else_has_label
)
1482 if (warn_notreached
)
1483 remove_useless_stmts_warn_notreached (else_clause
);
1484 *stmt_p
= then_clause
;
1485 data
->repeat
= true;
1487 else if (integer_zerop (cond
) && !then_has_label
)
1489 if (warn_notreached
)
1490 remove_useless_stmts_warn_notreached (then_clause
);
1491 *stmt_p
= else_clause
;
1492 data
->repeat
= true;
1495 /* Check a couple of simple things on then/else with single stmts. */
1498 tree then_stmt
= expr_only (then_clause
);
1499 tree else_stmt
= expr_only (else_clause
);
1501 /* Notice branches to a common destination. */
1502 if (then_stmt
&& else_stmt
1503 && TREE_CODE (then_stmt
) == GOTO_EXPR
1504 && TREE_CODE (else_stmt
) == GOTO_EXPR
1505 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1507 *stmt_p
= then_stmt
;
1508 data
->repeat
= true;
1511 /* If the THEN/ELSE clause merely assigns a value to a variable or
1512 parameter which is already known to contain that value, then
1513 remove the useless THEN/ELSE clause. */
1514 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1517 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1518 && TREE_OPERAND (else_stmt
, 0) == cond
1519 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1520 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1522 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1523 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1524 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1525 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1527 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1528 ? then_stmt
: else_stmt
);
1529 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1530 ? &COND_EXPR_THEN (*stmt_p
)
1531 : &COND_EXPR_ELSE (*stmt_p
));
1534 && TREE_CODE (stmt
) == MODIFY_EXPR
1535 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1536 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1537 *location
= alloc_stmt_list ();
1541 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1542 would be re-introduced during lowering. */
1543 data
->last_goto
= NULL
;
1548 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1550 bool save_may_branch
, save_may_throw
;
1551 bool this_may_branch
, this_may_throw
;
1553 /* Collect may_branch and may_throw information for the body only. */
1554 save_may_branch
= data
->may_branch
;
1555 save_may_throw
= data
->may_throw
;
1556 data
->may_branch
= false;
1557 data
->may_throw
= false;
1558 data
->last_goto
= NULL
;
1560 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1562 this_may_branch
= data
->may_branch
;
1563 this_may_throw
= data
->may_throw
;
1564 data
->may_branch
|= save_may_branch
;
1565 data
->may_throw
|= save_may_throw
;
1566 data
->last_goto
= NULL
;
1568 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1570 /* If the body is empty, then we can emit the FINALLY block without
1571 the enclosing TRY_FINALLY_EXPR. */
1572 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1574 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1575 data
->repeat
= true;
1578 /* If the handler is empty, then we can emit the TRY block without
1579 the enclosing TRY_FINALLY_EXPR. */
1580 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1582 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1583 data
->repeat
= true;
1586 /* If the body neither throws, nor branches, then we can safely
1587 string the TRY and FINALLY blocks together. */
1588 else if (!this_may_branch
&& !this_may_throw
)
1590 tree stmt
= *stmt_p
;
1591 *stmt_p
= TREE_OPERAND (stmt
, 0);
1592 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1593 data
->repeat
= true;
1599 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1601 bool save_may_throw
, this_may_throw
;
1602 tree_stmt_iterator i
;
1605 /* Collect may_throw information for the body only. */
1606 save_may_throw
= data
->may_throw
;
1607 data
->may_throw
= false;
1608 data
->last_goto
= NULL
;
1610 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1612 this_may_throw
= data
->may_throw
;
1613 data
->may_throw
= save_may_throw
;
1615 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1616 if (!this_may_throw
)
1618 if (warn_notreached
)
1619 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1620 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1621 data
->repeat
= true;
1625 /* Process the catch clause specially. We may be able to tell that
1626 no exceptions propagate past this point. */
1628 this_may_throw
= true;
1629 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1630 stmt
= tsi_stmt (i
);
1631 data
->last_goto
= NULL
;
1633 switch (TREE_CODE (stmt
))
1636 for (; !tsi_end_p (i
); tsi_next (&i
))
1638 stmt
= tsi_stmt (i
);
1639 /* If we catch all exceptions, then the body does not
1640 propagate exceptions past this point. */
1641 if (CATCH_TYPES (stmt
) == NULL
)
1642 this_may_throw
= false;
1643 data
->last_goto
= NULL
;
1644 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1648 case EH_FILTER_EXPR
:
1649 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1650 this_may_throw
= false;
1651 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1652 this_may_throw
= false;
1653 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1657 /* Otherwise this is a cleanup. */
1658 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1660 /* If the cleanup is empty, then we can emit the TRY block without
1661 the enclosing TRY_CATCH_EXPR. */
1662 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1664 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1665 data
->repeat
= true;
1669 data
->may_throw
|= this_may_throw
;
1674 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1678 /* First remove anything underneath the BIND_EXPR. */
1679 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1681 /* If the BIND_EXPR has no variables, then we can pull everything
1682 up one level and remove the BIND_EXPR, unless this is the toplevel
1683 BIND_EXPR for the current function or an inlined function.
1685 When this situation occurs we will want to apply this
1686 optimization again. */
1687 block
= BIND_EXPR_BLOCK (*stmt_p
);
1688 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1689 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1691 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1692 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1695 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1696 data
->repeat
= true;
1702 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1704 tree dest
= GOTO_DESTINATION (*stmt_p
);
1706 data
->may_branch
= true;
1707 data
->last_goto
= NULL
;
1709 /* Record the last goto expr, so that we can delete it if unnecessary. */
1710 if (TREE_CODE (dest
) == LABEL_DECL
)
1711 data
->last_goto
= stmt_p
;
1716 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1718 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1720 data
->has_label
= true;
1722 /* We do want to jump across non-local label receiver code. */
1723 if (DECL_NONLOCAL (label
))
1724 data
->last_goto
= NULL
;
1726 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1728 *data
->last_goto
= build_empty_stmt ();
1729 data
->repeat
= true;
1732 /* ??? Add something here to delete unused labels. */
1736 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1737 decl. This allows us to eliminate redundant or useless
1738 calls to "const" functions.
1740 Gimplifier already does the same operation, but we may notice functions
1741 being const and pure once their calls has been gimplified, so we need
1742 to update the flag. */
1745 update_call_expr_flags (tree call
)
1747 tree decl
= get_callee_fndecl (call
);
1750 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1751 TREE_SIDE_EFFECTS (call
) = 0;
1752 if (TREE_NOTHROW (decl
))
1753 TREE_NOTHROW (call
) = 1;
1757 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1760 notice_special_calls (tree t
)
1762 int flags
= call_expr_flags (t
);
1764 if (flags
& ECF_MAY_BE_ALLOCA
)
1765 current_function_calls_alloca
= true;
1766 if (flags
& ECF_RETURNS_TWICE
)
1767 current_function_calls_setjmp
= true;
1771 /* Clear flags set by notice_special_calls. Used by dead code removal
1772 to update the flags. */
1775 clear_special_calls (void)
1777 current_function_calls_alloca
= false;
1778 current_function_calls_setjmp
= false;
1783 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1787 switch (TREE_CODE (t
))
1790 remove_useless_stmts_cond (tp
, data
);
1793 case TRY_FINALLY_EXPR
:
1794 remove_useless_stmts_tf (tp
, data
);
1797 case TRY_CATCH_EXPR
:
1798 remove_useless_stmts_tc (tp
, data
);
1802 remove_useless_stmts_bind (tp
, data
);
1806 remove_useless_stmts_goto (tp
, data
);
1810 remove_useless_stmts_label (tp
, data
);
1815 data
->last_goto
= NULL
;
1816 data
->may_branch
= true;
1821 data
->last_goto
= NULL
;
1822 notice_special_calls (t
);
1823 update_call_expr_flags (t
);
1824 if (tree_could_throw_p (t
))
1825 data
->may_throw
= true;
1829 data
->last_goto
= NULL
;
1831 op
= get_call_expr_in (t
);
1834 update_call_expr_flags (op
);
1835 notice_special_calls (op
);
1837 if (tree_could_throw_p (t
))
1838 data
->may_throw
= true;
1841 case STATEMENT_LIST
:
1843 tree_stmt_iterator i
= tsi_start (t
);
1844 while (!tsi_end_p (i
))
1847 if (IS_EMPTY_STMT (t
))
1853 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1856 if (TREE_CODE (t
) == STATEMENT_LIST
)
1858 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1868 data
->last_goto
= NULL
;
1872 data
->last_goto
= NULL
;
1878 remove_useless_stmts (void)
1880 struct rus_data data
;
1882 clear_special_calls ();
1886 memset (&data
, 0, sizeof (data
));
1887 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1889 while (data
.repeat
);
1893 struct tree_opt_pass pass_remove_useless_stmts
=
1895 "useless", /* name */
1897 remove_useless_stmts
, /* execute */
1900 0, /* static_pass_number */
1902 PROP_gimple_any
, /* properties_required */
1903 0, /* properties_provided */
1904 0, /* properties_destroyed */
1905 0, /* todo_flags_start */
1906 TODO_dump_func
, /* todo_flags_finish */
1910 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1913 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1917 /* Since this block is no longer reachable, we can just delete all
1918 of its PHI nodes. */
1919 phi
= phi_nodes (bb
);
1922 tree next
= PHI_CHAIN (phi
);
1923 remove_phi_node (phi
, NULL_TREE
);
1927 /* Remove edges to BB's successors. */
1928 while (EDGE_COUNT (bb
->succs
) > 0)
1929 remove_edge (EDGE_SUCC (bb
, 0));
1933 /* Remove statements of basic block BB. */
1936 remove_bb (basic_block bb
)
1938 block_stmt_iterator i
;
1939 #ifdef USE_MAPPED_LOCATION
1940 source_location loc
= UNKNOWN_LOCATION
;
1942 source_locus loc
= 0;
1947 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1948 if (dump_flags
& TDF_DETAILS
)
1950 dump_bb (bb
, dump_file
, 0);
1951 fprintf (dump_file
, "\n");
1955 /* If we remove the header or the latch of a loop, mark the loop for
1956 removal by setting its header and latch to NULL. */
1959 struct loop
*loop
= bb
->loop_father
;
1961 if (loop
->latch
== bb
1962 || loop
->header
== bb
)
1965 loop
->header
= NULL
;
1969 /* Remove all the instructions in the block. */
1970 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
1972 tree stmt
= bsi_stmt (i
);
1973 if (TREE_CODE (stmt
) == LABEL_EXPR
1974 && FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)))
1976 basic_block new_bb
= bb
->prev_bb
;
1977 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
1980 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
1984 /* Release SSA definitions if we are in SSA. Note that we
1985 may be called when not in SSA. For example,
1986 final_cleanup calls this function via
1987 cleanup_tree_cfg. */
1989 release_defs (stmt
);
1994 /* Don't warn for removed gotos. Gotos are often removed due to
1995 jump threading, thus resulting in bogus warnings. Not great,
1996 since this way we lose warnings for gotos in the original
1997 program that are indeed unreachable. */
1998 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2000 #ifdef USE_MAPPED_LOCATION
2001 if (EXPR_HAS_LOCATION (stmt
))
2002 loc
= EXPR_LOCATION (stmt
);
2005 t
= EXPR_LOCUS (stmt
);
2006 if (t
&& LOCATION_LINE (*t
) > 0)
2012 /* If requested, give a warning that the first statement in the
2013 block is unreachable. We walk statements backwards in the
2014 loop above, so the last statement we process is the first statement
2016 #ifdef USE_MAPPED_LOCATION
2017 if (loc
> BUILTINS_LOCATION
)
2018 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2021 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2024 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2028 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2029 predicate VAL, return the edge that will be taken out of the block.
2030 If VAL does not match a unique edge, NULL is returned. */
2033 find_taken_edge (basic_block bb
, tree val
)
2037 stmt
= last_stmt (bb
);
2040 gcc_assert (is_ctrl_stmt (stmt
));
2043 if (! is_gimple_min_invariant (val
))
2046 if (TREE_CODE (stmt
) == COND_EXPR
)
2047 return find_taken_edge_cond_expr (bb
, val
);
2049 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2050 return find_taken_edge_switch_expr (bb
, val
);
2052 if (computed_goto_p (stmt
))
2053 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2058 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2059 statement, determine which of the outgoing edges will be taken out of the
2060 block. Return NULL if either edge may be taken. */
2063 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2068 dest
= label_to_block (val
);
2071 e
= find_edge (bb
, dest
);
2072 gcc_assert (e
!= NULL
);
2078 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2079 statement, determine which of the two edges will be taken out of the
2080 block. Return NULL if either edge may be taken. */
2083 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2085 edge true_edge
, false_edge
;
2087 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2089 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2090 return (zero_p (val
) ? false_edge
: true_edge
);
2093 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2094 statement, determine which edge will be taken out of the block. Return
2095 NULL if any edge may be taken. */
2098 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2100 tree switch_expr
, taken_case
;
2101 basic_block dest_bb
;
2104 switch_expr
= last_stmt (bb
);
2105 taken_case
= find_case_label_for_value (switch_expr
, val
);
2106 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2108 e
= find_edge (bb
, dest_bb
);
2114 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2115 We can make optimal use here of the fact that the case labels are
2116 sorted: We can do a binary search for a case matching VAL. */
2119 find_case_label_for_value (tree switch_expr
, tree val
)
2121 tree vec
= SWITCH_LABELS (switch_expr
);
2122 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2123 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2125 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2127 size_t i
= (high
+ low
) / 2;
2128 tree t
= TREE_VEC_ELT (vec
, i
);
2131 /* Cache the result of comparing CASE_LOW and val. */
2132 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2139 if (CASE_HIGH (t
) == NULL
)
2141 /* A singe-valued case label. */
2147 /* A case range. We can only handle integer ranges. */
2148 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2153 return default_case
;
2159 /*---------------------------------------------------------------------------
2161 ---------------------------------------------------------------------------*/
2163 /* Dump tree-specific information of block BB to file OUTF. */
2166 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2168 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2172 /* Dump a basic block on stderr. */
2175 debug_tree_bb (basic_block bb
)
2177 dump_bb (bb
, stderr
, 0);
2181 /* Dump basic block with index N on stderr. */
2184 debug_tree_bb_n (int n
)
2186 debug_tree_bb (BASIC_BLOCK (n
));
2187 return BASIC_BLOCK (n
);
2191 /* Dump the CFG on stderr.
2193 FLAGS are the same used by the tree dumping functions
2194 (see TDF_* in tree.h). */
2197 debug_tree_cfg (int flags
)
2199 dump_tree_cfg (stderr
, flags
);
2203 /* Dump the program showing basic block boundaries on the given FILE.
2205 FLAGS are the same used by the tree dumping functions (see TDF_* in
2209 dump_tree_cfg (FILE *file
, int flags
)
2211 if (flags
& TDF_DETAILS
)
2213 const char *funcname
2214 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2217 fprintf (file
, ";; Function %s\n\n", funcname
);
2218 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2219 n_basic_blocks
, n_edges
, last_basic_block
);
2221 brief_dump_cfg (file
);
2222 fprintf (file
, "\n");
2225 if (flags
& TDF_STATS
)
2226 dump_cfg_stats (file
);
2228 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2232 /* Dump CFG statistics on FILE. */
2235 dump_cfg_stats (FILE *file
)
2237 static long max_num_merged_labels
= 0;
2238 unsigned long size
, total
= 0;
2241 const char * const fmt_str
= "%-30s%-13s%12s\n";
2242 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2243 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2244 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2245 const char *funcname
2246 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2249 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2251 fprintf (file
, "---------------------------------------------------------\n");
2252 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2253 fprintf (file
, fmt_str
, "", " instances ", "used ");
2254 fprintf (file
, "---------------------------------------------------------\n");
2256 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2258 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2259 SCALE (size
), LABEL (size
));
2263 num_edges
+= EDGE_COUNT (bb
->succs
);
2264 size
= num_edges
* sizeof (struct edge_def
);
2266 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2268 fprintf (file
, "---------------------------------------------------------\n");
2269 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2271 fprintf (file
, "---------------------------------------------------------\n");
2272 fprintf (file
, "\n");
2274 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2275 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2277 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2278 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2280 fprintf (file
, "\n");
2284 /* Dump CFG statistics on stderr. Keep extern so that it's always
2285 linked in the final executable. */
2288 debug_cfg_stats (void)
2290 dump_cfg_stats (stderr
);
2294 /* Dump the flowgraph to a .vcg FILE. */
2297 tree_cfg2vcg (FILE *file
)
2302 const char *funcname
2303 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2305 /* Write the file header. */
2306 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2307 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2308 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2310 /* Write blocks and edges. */
2311 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2313 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2316 if (e
->flags
& EDGE_FAKE
)
2317 fprintf (file
, " linestyle: dotted priority: 10");
2319 fprintf (file
, " linestyle: solid priority: 100");
2321 fprintf (file
, " }\n");
2327 enum tree_code head_code
, end_code
;
2328 const char *head_name
, *end_name
;
2331 tree first
= first_stmt (bb
);
2332 tree last
= last_stmt (bb
);
2336 head_code
= TREE_CODE (first
);
2337 head_name
= tree_code_name
[head_code
];
2338 head_line
= get_lineno (first
);
2341 head_name
= "no-statement";
2345 end_code
= TREE_CODE (last
);
2346 end_name
= tree_code_name
[end_code
];
2347 end_line
= get_lineno (last
);
2350 end_name
= "no-statement";
2352 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2353 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2356 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2358 if (e
->dest
== EXIT_BLOCK_PTR
)
2359 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2361 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2363 if (e
->flags
& EDGE_FAKE
)
2364 fprintf (file
, " priority: 10 linestyle: dotted");
2366 fprintf (file
, " priority: 100 linestyle: solid");
2368 fprintf (file
, " }\n");
2371 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2375 fputs ("}\n\n", file
);
2380 /*---------------------------------------------------------------------------
2381 Miscellaneous helpers
2382 ---------------------------------------------------------------------------*/
2384 /* Return true if T represents a stmt that always transfers control. */
2387 is_ctrl_stmt (tree t
)
2389 return (TREE_CODE (t
) == COND_EXPR
2390 || TREE_CODE (t
) == SWITCH_EXPR
2391 || TREE_CODE (t
) == GOTO_EXPR
2392 || TREE_CODE (t
) == RETURN_EXPR
2393 || TREE_CODE (t
) == RESX_EXPR
);
2397 /* Return true if T is a statement that may alter the flow of control
2398 (e.g., a call to a non-returning function). */
2401 is_ctrl_altering_stmt (tree t
)
2406 call
= get_call_expr_in (t
);
2409 /* A non-pure/const CALL_EXPR alters flow control if the current
2410 function has nonlocal labels. */
2411 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2414 /* A CALL_EXPR also alters control flow if it does not return. */
2415 if (call_expr_flags (call
) & ECF_NORETURN
)
2419 /* If a statement can throw, it alters control flow. */
2420 return tree_can_throw_internal (t
);
2424 /* Return true if T is a computed goto. */
2427 computed_goto_p (tree t
)
2429 return (TREE_CODE (t
) == GOTO_EXPR
2430 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2434 /* Checks whether EXPR is a simple local goto. */
2437 simple_goto_p (tree expr
)
2439 return (TREE_CODE (expr
) == GOTO_EXPR
2440 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2444 /* Return true if T should start a new basic block. PREV_T is the
2445 statement preceding T. It is used when T is a label or a case label.
2446 Labels should only start a new basic block if their previous statement
2447 wasn't a label. Otherwise, sequence of labels would generate
2448 unnecessary basic blocks that only contain a single label. */
2451 stmt_starts_bb_p (tree t
, tree prev_t
)
2456 /* LABEL_EXPRs start a new basic block only if the preceding
2457 statement wasn't a label of the same type. This prevents the
2458 creation of consecutive blocks that have nothing but a single
2460 if (TREE_CODE (t
) == LABEL_EXPR
)
2462 /* Nonlocal and computed GOTO targets always start a new block. */
2463 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2464 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2467 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2469 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2472 cfg_stats
.num_merged_labels
++;
2483 /* Return true if T should end a basic block. */
2486 stmt_ends_bb_p (tree t
)
2488 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2492 /* Add gotos that used to be represented implicitly in the CFG. */
2495 disband_implicit_edges (void)
2498 block_stmt_iterator last
;
2505 last
= bsi_last (bb
);
2506 stmt
= last_stmt (bb
);
2508 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2510 /* Remove superfluous gotos from COND_EXPR branches. Moved
2511 from cfg_remove_useless_stmts here since it violates the
2512 invariants for tree--cfg correspondence and thus fits better
2513 here where we do it anyway. */
2514 e
= find_edge (bb
, bb
->next_bb
);
2517 if (e
->flags
& EDGE_TRUE_VALUE
)
2518 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2519 else if (e
->flags
& EDGE_FALSE_VALUE
)
2520 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2523 e
->flags
|= EDGE_FALLTHRU
;
2529 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2531 /* Remove the RETURN_EXPR if we may fall though to the exit
2533 gcc_assert (single_succ_p (bb
));
2534 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2536 if (bb
->next_bb
== EXIT_BLOCK_PTR
2537 && !TREE_OPERAND (stmt
, 0))
2540 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2545 /* There can be no fallthru edge if the last statement is a control
2547 if (stmt
&& is_ctrl_stmt (stmt
))
2550 /* Find a fallthru edge and emit the goto if necessary. */
2551 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2552 if (e
->flags
& EDGE_FALLTHRU
)
2555 if (!e
|| e
->dest
== bb
->next_bb
)
2558 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2559 label
= tree_block_label (e
->dest
);
2561 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2562 #ifdef USE_MAPPED_LOCATION
2563 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2565 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2567 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2568 e
->flags
&= ~EDGE_FALLTHRU
;
2572 /* Remove block annotations and other datastructures. */
2575 delete_tree_cfg_annotations (void)
2577 label_to_block_map
= NULL
;
2581 /* Return the first statement in basic block BB. */
2584 first_stmt (basic_block bb
)
2586 block_stmt_iterator i
= bsi_start (bb
);
2587 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2591 /* Return the last statement in basic block BB. */
2594 last_stmt (basic_block bb
)
2596 block_stmt_iterator b
= bsi_last (bb
);
2597 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2601 /* Return a pointer to the last statement in block BB. */
2604 last_stmt_ptr (basic_block bb
)
2606 block_stmt_iterator last
= bsi_last (bb
);
2607 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2611 /* Return the last statement of an otherwise empty block. Return NULL
2612 if the block is totally empty, or if it contains more than one
2616 last_and_only_stmt (basic_block bb
)
2618 block_stmt_iterator i
= bsi_last (bb
);
2624 last
= bsi_stmt (i
);
2629 /* Empty statements should no longer appear in the instruction stream.
2630 Everything that might have appeared before should be deleted by
2631 remove_useless_stmts, and the optimizers should just bsi_remove
2632 instead of smashing with build_empty_stmt.
2634 Thus the only thing that should appear here in a block containing
2635 one executable statement is a label. */
2636 prev
= bsi_stmt (i
);
2637 if (TREE_CODE (prev
) == LABEL_EXPR
)
2644 /* Mark BB as the basic block holding statement T. */
2647 set_bb_for_stmt (tree t
, basic_block bb
)
2649 if (TREE_CODE (t
) == PHI_NODE
)
2651 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2653 tree_stmt_iterator i
;
2654 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2655 set_bb_for_stmt (tsi_stmt (i
), bb
);
2659 stmt_ann_t ann
= get_stmt_ann (t
);
2662 /* If the statement is a label, add the label to block-to-labels map
2663 so that we can speed up edge creation for GOTO_EXPRs. */
2664 if (TREE_CODE (t
) == LABEL_EXPR
)
2668 t
= LABEL_EXPR_LABEL (t
);
2669 uid
= LABEL_DECL_UID (t
);
2672 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2673 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2674 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2677 /* We're moving an existing label. Make sure that we've
2678 removed it from the old block. */
2679 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2680 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2685 /* Finds iterator for STMT. */
2687 extern block_stmt_iterator
2688 bsi_for_stmt (tree stmt
)
2690 block_stmt_iterator bsi
;
2692 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2693 if (bsi_stmt (bsi
) == stmt
)
2699 /* Mark statement T as modified, and update it. */
2701 update_modified_stmts (tree t
)
2703 if (TREE_CODE (t
) == STATEMENT_LIST
)
2705 tree_stmt_iterator i
;
2707 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2709 stmt
= tsi_stmt (i
);
2710 update_stmt_if_modified (stmt
);
2714 update_stmt_if_modified (t
);
2717 /* Insert statement (or statement list) T before the statement
2718 pointed-to by iterator I. M specifies how to update iterator I
2719 after insertion (see enum bsi_iterator_update). */
2722 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2724 set_bb_for_stmt (t
, i
->bb
);
2725 update_modified_stmts (t
);
2726 tsi_link_before (&i
->tsi
, t
, m
);
2730 /* Insert statement (or statement list) T after the statement
2731 pointed-to by iterator I. M specifies how to update iterator I
2732 after insertion (see enum bsi_iterator_update). */
2735 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2737 set_bb_for_stmt (t
, i
->bb
);
2738 update_modified_stmts (t
);
2739 tsi_link_after (&i
->tsi
, t
, m
);
2743 /* Remove the statement pointed to by iterator I. The iterator is updated
2744 to the next statement. */
2747 bsi_remove (block_stmt_iterator
*i
)
2749 tree t
= bsi_stmt (*i
);
2750 set_bb_for_stmt (t
, NULL
);
2751 delink_stmt_imm_use (t
);
2752 tsi_delink (&i
->tsi
);
2753 mark_stmt_modified (t
);
2757 /* Move the statement at FROM so it comes right after the statement at TO. */
2760 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2762 tree stmt
= bsi_stmt (*from
);
2764 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2768 /* Move the statement at FROM so it comes right before the statement at TO. */
2771 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2773 tree stmt
= bsi_stmt (*from
);
2775 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2779 /* Move the statement at FROM to the end of basic block BB. */
2782 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2784 block_stmt_iterator last
= bsi_last (bb
);
2786 /* Have to check bsi_end_p because it could be an empty block. */
2787 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2788 bsi_move_before (from
, &last
);
2790 bsi_move_after (from
, &last
);
2794 /* Replace the contents of the statement pointed to by iterator BSI
2795 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2796 information of the original statement is preserved. */
2799 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2802 tree orig_stmt
= bsi_stmt (*bsi
);
2804 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2805 set_bb_for_stmt (stmt
, bsi
->bb
);
2807 /* Preserve EH region information from the original statement, if
2808 requested by the caller. */
2809 if (preserve_eh_info
)
2811 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2813 add_stmt_to_eh_region (stmt
, eh_region
);
2816 delink_stmt_imm_use (orig_stmt
);
2817 *bsi_stmt_ptr (*bsi
) = stmt
;
2818 mark_stmt_modified (stmt
);
2819 update_modified_stmts (stmt
);
2823 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2824 is made to place the statement in an existing basic block, but
2825 sometimes that isn't possible. When it isn't possible, the edge is
2826 split and the statement is added to the new block.
2828 In all cases, the returned *BSI points to the correct location. The
2829 return value is true if insertion should be done after the location,
2830 or false if it should be done before the location. If new basic block
2831 has to be created, it is stored in *NEW_BB. */
2834 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2835 basic_block
*new_bb
)
2837 basic_block dest
, src
;
2843 /* If the destination has one predecessor which has no PHI nodes,
2844 insert there. Except for the exit block.
2846 The requirement for no PHI nodes could be relaxed. Basically we
2847 would have to examine the PHIs to prove that none of them used
2848 the value set by the statement we want to insert on E. That
2849 hardly seems worth the effort. */
2850 if (single_pred_p (dest
)
2851 && ! phi_nodes (dest
)
2852 && dest
!= EXIT_BLOCK_PTR
)
2854 *bsi
= bsi_start (dest
);
2855 if (bsi_end_p (*bsi
))
2858 /* Make sure we insert after any leading labels. */
2859 tmp
= bsi_stmt (*bsi
);
2860 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2863 if (bsi_end_p (*bsi
))
2865 tmp
= bsi_stmt (*bsi
);
2868 if (bsi_end_p (*bsi
))
2870 *bsi
= bsi_last (dest
);
2877 /* If the source has one successor, the edge is not abnormal and
2878 the last statement does not end a basic block, insert there.
2879 Except for the entry block. */
2881 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2882 && single_succ_p (src
)
2883 && src
!= ENTRY_BLOCK_PTR
)
2885 *bsi
= bsi_last (src
);
2886 if (bsi_end_p (*bsi
))
2889 tmp
= bsi_stmt (*bsi
);
2890 if (!stmt_ends_bb_p (tmp
))
2893 /* Insert code just before returning the value. We may need to decompose
2894 the return in the case it contains non-trivial operand. */
2895 if (TREE_CODE (tmp
) == RETURN_EXPR
)
2897 tree op
= TREE_OPERAND (tmp
, 0);
2898 if (!is_gimple_val (op
))
2900 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
2901 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
2902 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
2909 /* Otherwise, create a new basic block, and split this edge. */
2910 dest
= split_edge (e
);
2913 e
= single_pred_edge (dest
);
2918 /* This routine will commit all pending edge insertions, creating any new
2919 basic blocks which are necessary. */
2922 bsi_commit_edge_inserts (void)
2928 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
2931 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2932 bsi_commit_one_edge_insert (e
, NULL
);
2936 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2937 to this block, otherwise set it to NULL. */
2940 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
2944 if (PENDING_STMT (e
))
2946 block_stmt_iterator bsi
;
2947 tree stmt
= PENDING_STMT (e
);
2949 PENDING_STMT (e
) = NULL_TREE
;
2951 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
2952 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
2954 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
2959 /* Add STMT to the pending list of edge E. No actual insertion is
2960 made until a call to bsi_commit_edge_inserts () is made. */
2963 bsi_insert_on_edge (edge e
, tree stmt
)
2965 append_to_statement_list (stmt
, &PENDING_STMT (e
));
2968 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
2969 block has to be created, it is returned. */
2972 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
2974 block_stmt_iterator bsi
;
2975 basic_block new_bb
= NULL
;
2977 gcc_assert (!PENDING_STMT (e
));
2979 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
2980 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
2982 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
2987 /*---------------------------------------------------------------------------
2988 Tree specific functions for CFG manipulation
2989 ---------------------------------------------------------------------------*/
2991 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
2994 reinstall_phi_args (edge new_edge
, edge old_edge
)
2998 if (!PENDING_STMT (old_edge
))
3001 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3003 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3005 tree result
= TREE_PURPOSE (var
);
3006 tree arg
= TREE_VALUE (var
);
3008 gcc_assert (result
== PHI_RESULT (phi
));
3010 add_phi_arg (phi
, arg
, new_edge
);
3013 PENDING_STMT (old_edge
) = NULL
;
3016 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3017 Abort on abnormal edges. */
3020 tree_split_edge (edge edge_in
)
3022 basic_block new_bb
, after_bb
, dest
, src
;
3025 /* Abnormal edges cannot be split. */
3026 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3029 dest
= edge_in
->dest
;
3031 /* Place the new block in the block list. Try to keep the new block
3032 near its "logical" location. This is of most help to humans looking
3033 at debugging dumps. */
3034 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3035 after_bb
= edge_in
->src
;
3037 after_bb
= dest
->prev_bb
;
3039 new_bb
= create_empty_bb (after_bb
);
3040 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3041 new_bb
->count
= edge_in
->count
;
3042 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3043 new_edge
->probability
= REG_BR_PROB_BASE
;
3044 new_edge
->count
= edge_in
->count
;
3046 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3048 reinstall_phi_args (new_edge
, e
);
3054 /* Return true when BB has label LABEL in it. */
3057 has_label_p (basic_block bb
, tree label
)
3059 block_stmt_iterator bsi
;
3061 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3063 tree stmt
= bsi_stmt (bsi
);
3065 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3067 if (LABEL_EXPR_LABEL (stmt
) == label
)
3074 /* Callback for walk_tree, check that all elements with address taken are
3075 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3076 inside a PHI node. */
3079 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3082 bool in_phi
= (data
!= NULL
);
3087 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3088 #define CHECK_OP(N, MSG) \
3089 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3090 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3092 switch (TREE_CODE (t
))
3095 if (SSA_NAME_IN_FREE_LIST (t
))
3097 error ("SSA name in freelist but still referenced");
3103 x
= fold (ASSERT_EXPR_COND (t
));
3104 if (x
== boolean_false_node
)
3106 error ("ASSERT_EXPR with an always-false condition");
3112 x
= TREE_OPERAND (t
, 0);
3113 if (TREE_CODE (x
) == BIT_FIELD_REF
3114 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3116 error ("GIMPLE register modified with BIT_FIELD_REF");
3125 bool old_side_effects
;
3128 bool new_side_effects
;
3130 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3131 dead PHIs that take the address of something. But if the PHI
3132 result is dead, the fact that it takes the address of anything
3133 is irrelevant. Because we can not tell from here if a PHI result
3134 is dead, we just skip this check for PHIs altogether. This means
3135 we may be missing "valid" checks, but what can you do?
3136 This was PR19217. */
3140 old_invariant
= TREE_INVARIANT (t
);
3141 old_constant
= TREE_CONSTANT (t
);
3142 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3144 recompute_tree_invarant_for_addr_expr (t
);
3145 new_invariant
= TREE_INVARIANT (t
);
3146 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3147 new_constant
= TREE_CONSTANT (t
);
3149 if (old_invariant
!= new_invariant
)
3151 error ("invariant not recomputed when ADDR_EXPR changed");
3155 if (old_constant
!= new_constant
)
3157 error ("constant not recomputed when ADDR_EXPR changed");
3160 if (old_side_effects
!= new_side_effects
)
3162 error ("side effects not recomputed when ADDR_EXPR changed");
3166 /* Skip any references (they will be checked when we recurse down the
3167 tree) and ensure that any variable used as a prefix is marked
3169 for (x
= TREE_OPERAND (t
, 0);
3170 handled_component_p (x
);
3171 x
= TREE_OPERAND (x
, 0))
3174 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3176 if (!TREE_ADDRESSABLE (x
))
3178 error ("address taken, but ADDRESSABLE bit not set");
3185 x
= COND_EXPR_COND (t
);
3186 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3188 error ("non-boolean used in condition");
3191 if (!is_gimple_condexpr (x
))
3193 error ("invalid conditional operand");
3200 case FIX_TRUNC_EXPR
:
3202 case FIX_FLOOR_EXPR
:
3203 case FIX_ROUND_EXPR
:
3208 case NON_LVALUE_EXPR
:
3209 case TRUTH_NOT_EXPR
:
3210 CHECK_OP (0, "invalid operand to unary operator");
3217 case ARRAY_RANGE_REF
:
3219 case VIEW_CONVERT_EXPR
:
3220 /* We have a nest of references. Verify that each of the operands
3221 that determine where to reference is either a constant or a variable,
3222 verify that the base is valid, and then show we've already checked
3224 while (handled_component_p (t
))
3226 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3227 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3228 else if (TREE_CODE (t
) == ARRAY_REF
3229 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3231 CHECK_OP (1, "invalid array index");
3232 if (TREE_OPERAND (t
, 2))
3233 CHECK_OP (2, "invalid array lower bound");
3234 if (TREE_OPERAND (t
, 3))
3235 CHECK_OP (3, "invalid array stride");
3237 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3239 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3240 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3243 t
= TREE_OPERAND (t
, 0);
3246 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3248 error ("invalid reference prefix");
3260 case UNORDERED_EXPR
:
3271 case TRUNC_DIV_EXPR
:
3273 case FLOOR_DIV_EXPR
:
3274 case ROUND_DIV_EXPR
:
3275 case TRUNC_MOD_EXPR
:
3277 case FLOOR_MOD_EXPR
:
3278 case ROUND_MOD_EXPR
:
3280 case EXACT_DIV_EXPR
:
3290 CHECK_OP (0, "invalid operand to binary operator");
3291 CHECK_OP (1, "invalid operand to binary operator");
3303 /* Verify STMT, return true if STMT is not in GIMPLE form.
3304 TODO: Implement type checking. */
3307 verify_stmt (tree stmt
, bool last_in_block
)
3311 if (!is_gimple_stmt (stmt
))
3313 error ("is not a valid GIMPLE statement");
3317 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3320 debug_generic_stmt (addr
);
3324 /* If the statement is marked as part of an EH region, then it is
3325 expected that the statement could throw. Verify that when we
3326 have optimizations that simplify statements such that we prove
3327 that they cannot throw, that we update other data structures
3329 if (lookup_stmt_eh_region (stmt
) >= 0)
3331 if (!tree_could_throw_p (stmt
))
3333 error ("statement marked for throw, but doesn%'t");
3336 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3338 error ("statement marked for throw in middle of block");
3346 debug_generic_stmt (stmt
);
3351 /* Return true when the T can be shared. */
3354 tree_node_can_be_shared (tree t
)
3356 if (IS_TYPE_OR_DECL_P (t
)
3357 /* We check for constants explicitly since they are not considered
3358 gimple invariants if they overflowed. */
3359 || CONSTANT_CLASS_P (t
)
3360 || is_gimple_min_invariant (t
)
3361 || TREE_CODE (t
) == SSA_NAME
3362 || t
== error_mark_node
)
3365 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3368 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3369 /* We check for constants explicitly since they are not considered
3370 gimple invariants if they overflowed. */
3371 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3372 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3373 || (TREE_CODE (t
) == COMPONENT_REF
3374 || TREE_CODE (t
) == REALPART_EXPR
3375 || TREE_CODE (t
) == IMAGPART_EXPR
))
3376 t
= TREE_OPERAND (t
, 0);
3385 /* Called via walk_trees. Verify tree sharing. */
3388 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3390 htab_t htab
= (htab_t
) data
;
3393 if (tree_node_can_be_shared (*tp
))
3395 *walk_subtrees
= false;
3399 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3408 /* Verify the GIMPLE statement chain. */
3414 block_stmt_iterator bsi
;
3419 timevar_push (TV_TREE_STMT_VERIFY
);
3420 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3427 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3429 int phi_num_args
= PHI_NUM_ARGS (phi
);
3431 if (bb_for_stmt (phi
) != bb
)
3433 error ("bb_for_stmt (phi) is set to a wrong basic block");
3437 for (i
= 0; i
< phi_num_args
; i
++)
3439 tree t
= PHI_ARG_DEF (phi
, i
);
3442 /* Addressable variables do have SSA_NAMEs but they
3443 are not considered gimple values. */
3444 if (TREE_CODE (t
) != SSA_NAME
3445 && TREE_CODE (t
) != FUNCTION_DECL
3446 && !is_gimple_val (t
))
3448 error ("PHI def is not a GIMPLE value");
3449 debug_generic_stmt (phi
);
3450 debug_generic_stmt (t
);
3454 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3457 debug_generic_stmt (addr
);
3461 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3464 error ("incorrect sharing of tree nodes");
3465 debug_generic_stmt (phi
);
3466 debug_generic_stmt (addr
);
3472 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3474 tree stmt
= bsi_stmt (bsi
);
3476 if (bb_for_stmt (stmt
) != bb
)
3478 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3483 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3484 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3487 error ("incorrect sharing of tree nodes");
3488 debug_generic_stmt (stmt
);
3489 debug_generic_stmt (addr
);
3496 internal_error ("verify_stmts failed");
3499 timevar_pop (TV_TREE_STMT_VERIFY
);
3503 /* Verifies that the flow information is OK. */
3506 tree_verify_flow_info (void)
3510 block_stmt_iterator bsi
;
3515 if (ENTRY_BLOCK_PTR
->stmt_list
)
3517 error ("ENTRY_BLOCK has a statement list associated with it");
3521 if (EXIT_BLOCK_PTR
->stmt_list
)
3523 error ("EXIT_BLOCK has a statement list associated with it");
3527 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3528 if (e
->flags
& EDGE_FALLTHRU
)
3530 error ("fallthru to exit from bb %d", e
->src
->index
);
3536 bool found_ctrl_stmt
= false;
3540 /* Skip labels on the start of basic block. */
3541 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3543 tree prev_stmt
= stmt
;
3545 stmt
= bsi_stmt (bsi
);
3547 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3550 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3552 error ("nonlocal label %s is not first "
3553 "in a sequence of labels in bb %d",
3554 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3559 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3561 error ("label %s to block does not match in bb %d",
3562 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3567 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3568 != current_function_decl
)
3570 error ("label %s has incorrect context in bb %d",
3571 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3577 /* Verify that body of basic block BB is free of control flow. */
3578 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3580 tree stmt
= bsi_stmt (bsi
);
3582 if (found_ctrl_stmt
)
3584 error ("control flow in the middle of basic block %d",
3589 if (stmt_ends_bb_p (stmt
))
3590 found_ctrl_stmt
= true;
3592 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3594 error ("label %s in the middle of basic block %d",
3595 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3600 bsi
= bsi_last (bb
);
3601 if (bsi_end_p (bsi
))
3604 stmt
= bsi_stmt (bsi
);
3606 err
|= verify_eh_edges (stmt
);
3608 if (is_ctrl_stmt (stmt
))
3610 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3611 if (e
->flags
& EDGE_FALLTHRU
)
3613 error ("fallthru edge after a control statement in bb %d",
3619 switch (TREE_CODE (stmt
))
3625 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3626 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3628 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3632 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3634 if (!true_edge
|| !false_edge
3635 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3636 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3637 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3638 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3639 || EDGE_COUNT (bb
->succs
) >= 3)
3641 error ("wrong outgoing edge flags at end of bb %d",
3646 if (!has_label_p (true_edge
->dest
,
3647 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3649 error ("%<then%> label does not match edge at end of bb %d",
3654 if (!has_label_p (false_edge
->dest
,
3655 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3657 error ("%<else%> label does not match edge at end of bb %d",
3665 if (simple_goto_p (stmt
))
3667 error ("explicit goto at end of bb %d", bb
->index
);
3672 /* FIXME. We should double check that the labels in the
3673 destination blocks have their address taken. */
3674 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3675 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3676 | EDGE_FALSE_VALUE
))
3677 || !(e
->flags
& EDGE_ABNORMAL
))
3679 error ("wrong outgoing edge flags at end of bb %d",
3687 if (!single_succ_p (bb
)
3688 || (single_succ_edge (bb
)->flags
3689 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3690 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3692 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3695 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3697 error ("return edge does not point to exit in bb %d",
3710 vec
= SWITCH_LABELS (stmt
);
3711 n
= TREE_VEC_LENGTH (vec
);
3713 /* Mark all the destination basic blocks. */
3714 for (i
= 0; i
< n
; ++i
)
3716 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3717 basic_block label_bb
= label_to_block (lab
);
3719 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3720 label_bb
->aux
= (void *)1;
3723 /* Verify that the case labels are sorted. */
3724 prev
= TREE_VEC_ELT (vec
, 0);
3725 for (i
= 1; i
< n
- 1; ++i
)
3727 tree c
= TREE_VEC_ELT (vec
, i
);
3730 error ("found default case not at end of case vector");
3734 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3736 error ("case labels not sorted:");
3737 print_generic_expr (stderr
, prev
, 0);
3738 fprintf (stderr
," is greater than ");
3739 print_generic_expr (stderr
, c
, 0);
3740 fprintf (stderr
," but comes before it.\n");
3745 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3747 error ("no default case found at end of case vector");
3751 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3755 error ("extra outgoing edge %d->%d",
3756 bb
->index
, e
->dest
->index
);
3759 e
->dest
->aux
= (void *)2;
3760 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3761 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3763 error ("wrong outgoing edge flags at end of bb %d",
3769 /* Check that we have all of them. */
3770 for (i
= 0; i
< n
; ++i
)
3772 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3773 basic_block label_bb
= label_to_block (lab
);
3775 if (label_bb
->aux
!= (void *)2)
3777 error ("missing edge %i->%i",
3778 bb
->index
, label_bb
->index
);
3783 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3784 e
->dest
->aux
= (void *)0;
3791 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3792 verify_dominators (CDI_DOMINATORS
);
3798 /* Updates phi nodes after creating a forwarder block joined
3799 by edge FALLTHRU. */
3802 tree_make_forwarder_block (edge fallthru
)
3806 basic_block dummy
, bb
;
3807 tree phi
, new_phi
, var
;
3809 dummy
= fallthru
->src
;
3810 bb
= fallthru
->dest
;
3812 if (single_pred_p (bb
))
3815 /* If we redirected a branch we must create new phi nodes at the
3817 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3819 var
= PHI_RESULT (phi
);
3820 new_phi
= create_phi_node (var
, bb
);
3821 SSA_NAME_DEF_STMT (var
) = new_phi
;
3822 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3823 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3826 /* Ensure that the PHI node chain is in the same order. */
3827 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3829 /* Add the arguments we have stored on edges. */
3830 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3835 flush_pending_stmts (e
);
3840 /* Return a non-special label in the head of basic block BLOCK.
3841 Create one if it doesn't exist. */
3844 tree_block_label (basic_block bb
)
3846 block_stmt_iterator i
, s
= bsi_start (bb
);
3850 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3852 stmt
= bsi_stmt (i
);
3853 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3855 label
= LABEL_EXPR_LABEL (stmt
);
3856 if (!DECL_NONLOCAL (label
))
3859 bsi_move_before (&i
, &s
);
3864 label
= create_artificial_label ();
3865 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3866 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3871 /* Attempt to perform edge redirection by replacing a possibly complex
3872 jump instruction by a goto or by removing the jump completely.
3873 This can apply only if all edges now point to the same block. The
3874 parameters and return values are equivalent to
3875 redirect_edge_and_branch. */
3878 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
3880 basic_block src
= e
->src
;
3881 block_stmt_iterator b
;
3884 /* We can replace or remove a complex jump only when we have exactly
3886 if (EDGE_COUNT (src
->succs
) != 2
3887 /* Verify that all targets will be TARGET. Specifically, the
3888 edge that is not E must also go to TARGET. */
3889 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
3895 stmt
= bsi_stmt (b
);
3897 if (TREE_CODE (stmt
) == COND_EXPR
3898 || TREE_CODE (stmt
) == SWITCH_EXPR
)
3901 e
= ssa_redirect_edge (e
, target
);
3902 e
->flags
= EDGE_FALLTHRU
;
3910 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3911 edge representing the redirected branch. */
3914 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
3916 basic_block bb
= e
->src
;
3917 block_stmt_iterator bsi
;
3921 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3924 if (e
->src
!= ENTRY_BLOCK_PTR
3925 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
3928 if (e
->dest
== dest
)
3931 label
= tree_block_label (dest
);
3933 bsi
= bsi_last (bb
);
3934 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
3936 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
3939 stmt
= (e
->flags
& EDGE_TRUE_VALUE
3940 ? COND_EXPR_THEN (stmt
)
3941 : COND_EXPR_ELSE (stmt
));
3942 GOTO_DESTINATION (stmt
) = label
;
3946 /* No non-abnormal edges should lead from a non-simple goto, and
3947 simple ones should be represented implicitly. */
3952 tree cases
= get_cases_for_edge (e
, stmt
);
3954 /* If we have a list of cases associated with E, then use it
3955 as it's a lot faster than walking the entire case vector. */
3958 edge e2
= find_edge (e
->src
, dest
);
3965 CASE_LABEL (cases
) = label
;
3966 cases
= TREE_CHAIN (cases
);
3969 /* If there was already an edge in the CFG, then we need
3970 to move all the cases associated with E to E2. */
3973 tree cases2
= get_cases_for_edge (e2
, stmt
);
3975 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
3976 TREE_CHAIN (cases2
) = first
;
3981 tree vec
= SWITCH_LABELS (stmt
);
3982 size_t i
, n
= TREE_VEC_LENGTH (vec
);
3984 for (i
= 0; i
< n
; i
++)
3986 tree elt
= TREE_VEC_ELT (vec
, i
);
3988 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
3989 CASE_LABEL (elt
) = label
;
3998 e
->flags
|= EDGE_FALLTHRU
;
4002 /* Otherwise it must be a fallthru edge, and we don't need to
4003 do anything besides redirecting it. */
4004 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4008 /* Update/insert PHI nodes as necessary. */
4010 /* Now update the edges in the CFG. */
4011 e
= ssa_redirect_edge (e
, dest
);
4017 /* Simple wrapper, as we can always redirect fallthru edges. */
4020 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4022 e
= tree_redirect_edge_and_branch (e
, dest
);
4029 /* Splits basic block BB after statement STMT (but at least after the
4030 labels). If STMT is NULL, BB is split just after the labels. */
4033 tree_split_block (basic_block bb
, void *stmt
)
4035 block_stmt_iterator bsi
, bsi_tgt
;
4041 new_bb
= create_empty_bb (bb
);
4043 /* Redirect the outgoing edges. */
4044 new_bb
->succs
= bb
->succs
;
4046 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4049 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4052 /* Move everything from BSI to the new basic block. */
4053 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4055 act
= bsi_stmt (bsi
);
4056 if (TREE_CODE (act
) == LABEL_EXPR
)
4069 bsi_tgt
= bsi_start (new_bb
);
4070 while (!bsi_end_p (bsi
))
4072 act
= bsi_stmt (bsi
);
4074 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4081 /* Moves basic block BB after block AFTER. */
4084 tree_move_block_after (basic_block bb
, basic_block after
)
4086 if (bb
->prev_bb
== after
)
4090 link_block (bb
, after
);
4096 /* Return true if basic_block can be duplicated. */
4099 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4105 /* Create a duplicate of the basic block BB. NOTE: This does not
4106 preserve SSA form. */
4109 tree_duplicate_bb (basic_block bb
)
4112 block_stmt_iterator bsi
, bsi_tgt
;
4115 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4117 /* Copy the PHI nodes. We ignore PHI node arguments here because
4118 the incoming edges have not been setup yet. */
4119 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4121 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4122 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4125 /* Keep the chain of PHI nodes in the same order so that they can be
4126 updated by ssa_redirect_edge. */
4127 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4129 bsi_tgt
= bsi_start (new_bb
);
4130 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4132 def_operand_p def_p
;
4133 ssa_op_iter op_iter
;
4137 stmt
= bsi_stmt (bsi
);
4138 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4141 /* Create a new copy of STMT and duplicate STMT's virtual
4143 copy
= unshare_expr (stmt
);
4144 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4145 copy_virtual_operands (copy
, stmt
);
4146 region
= lookup_stmt_eh_region (stmt
);
4148 add_stmt_to_eh_region (copy
, region
);
4150 /* Create new names for all the definitions created by COPY and
4151 add replacement mappings for each new name. */
4152 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4153 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4160 /* Basic block BB_COPY was created by code duplication. Add phi node
4161 arguments for edges going out of BB_COPY. The blocks that were
4162 duplicated have BB_DUPLICATED set. */
4165 add_phi_args_after_copy_bb (basic_block bb_copy
)
4167 basic_block bb
, dest
;
4170 tree phi
, phi_copy
, phi_next
, def
;
4172 bb
= get_bb_original (bb_copy
);
4174 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4176 if (!phi_nodes (e_copy
->dest
))
4179 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4180 dest
= get_bb_original (e_copy
->dest
);
4182 dest
= e_copy
->dest
;
4184 e
= find_edge (bb
, dest
);
4187 /* During loop unrolling the target of the latch edge is copied.
4188 In this case we are not looking for edge to dest, but to
4189 duplicated block whose original was dest. */
4190 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4191 if ((e
->dest
->flags
& BB_DUPLICATED
)
4192 && get_bb_original (e
->dest
) == dest
)
4195 gcc_assert (e
!= NULL
);
4198 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4200 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4202 phi_next
= PHI_CHAIN (phi
);
4203 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4204 add_phi_arg (phi_copy
, def
, e_copy
);
4209 /* Blocks in REGION_COPY array of length N_REGION were created by
4210 duplication of basic blocks. Add phi node arguments for edges
4211 going from these blocks. */
4214 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4218 for (i
= 0; i
< n_region
; i
++)
4219 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4221 for (i
= 0; i
< n_region
; i
++)
4222 add_phi_args_after_copy_bb (region_copy
[i
]);
4224 for (i
= 0; i
< n_region
; i
++)
4225 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4228 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4229 important exit edge EXIT. By important we mean that no SSA name defined
4230 inside region is live over the other exit edges of the region. All entry
4231 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4232 to the duplicate of the region. SSA form, dominance and loop information
4233 is updated. The new basic blocks are stored to REGION_COPY in the same
4234 order as they had in REGION, provided that REGION_COPY is not NULL.
4235 The function returns false if it is unable to copy the region,
4239 tree_duplicate_sese_region (edge entry
, edge exit
,
4240 basic_block
*region
, unsigned n_region
,
4241 basic_block
*region_copy
)
4244 bool free_region_copy
= false, copying_header
= false;
4245 struct loop
*loop
= entry
->dest
->loop_father
;
4249 int total_freq
= 0, entry_freq
= 0;
4250 gcov_type total_count
= 0, entry_count
= 0;
4252 if (!can_copy_bbs_p (region
, n_region
))
4255 /* Some sanity checking. Note that we do not check for all possible
4256 missuses of the functions. I.e. if you ask to copy something weird,
4257 it will work, but the state of structures probably will not be
4259 for (i
= 0; i
< n_region
; i
++)
4261 /* We do not handle subloops, i.e. all the blocks must belong to the
4263 if (region
[i
]->loop_father
!= loop
)
4266 if (region
[i
] != entry
->dest
4267 && region
[i
] == loop
->header
)
4273 /* In case the function is used for loop header copying (which is the primary
4274 use), ensure that EXIT and its copy will be new latch and entry edges. */
4275 if (loop
->header
== entry
->dest
)
4277 copying_header
= true;
4278 loop
->copy
= loop
->outer
;
4280 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4283 for (i
= 0; i
< n_region
; i
++)
4284 if (region
[i
] != exit
->src
4285 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4291 region_copy
= xmalloc (sizeof (basic_block
) * n_region
);
4292 free_region_copy
= true;
4295 gcc_assert (!need_ssa_update_p ());
4297 /* Record blocks outside the region that are dominated by something
4299 doms
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4300 initialize_original_copy_tables ();
4302 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4304 if (entry
->dest
->count
)
4306 total_count
= entry
->dest
->count
;
4307 entry_count
= entry
->count
;
4308 /* Fix up corner cases, to avoid division by zero or creation of negative
4310 if (entry_count
> total_count
)
4311 entry_count
= total_count
;
4315 total_freq
= entry
->dest
->frequency
;
4316 entry_freq
= EDGE_FREQUENCY (entry
);
4317 /* Fix up corner cases, to avoid division by zero or creation of negative
4319 if (total_freq
== 0)
4321 else if (entry_freq
> total_freq
)
4322 entry_freq
= total_freq
;
4325 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
);
4328 scale_bbs_frequencies_gcov_type (region
, n_region
,
4329 total_count
- entry_count
,
4331 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4336 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4338 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4343 loop
->header
= exit
->dest
;
4344 loop
->latch
= exit
->src
;
4347 /* Redirect the entry and add the phi node arguments. */
4348 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4349 gcc_assert (redirected
!= NULL
);
4350 flush_pending_stmts (entry
);
4352 /* Concerning updating of dominators: We must recount dominators
4353 for entry block and its copy. Anything that is outside of the
4354 region, but was dominated by something inside needs recounting as
4356 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4357 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4358 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4361 /* Add the other PHI node arguments. */
4362 add_phi_args_after_copy (region_copy
, n_region
);
4364 /* Update the SSA web. */
4365 update_ssa (TODO_update_ssa
);
4367 if (free_region_copy
)
4370 free_original_copy_tables ();
4375 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4378 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4380 tree arg
, vars
, var
;
4381 bool ignore_topmost_bind
= false, any_var
= false;
4385 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4387 arg
= DECL_ARGUMENTS (fn
);
4390 print_generic_expr (file
, arg
, dump_flags
);
4391 if (TREE_CHAIN (arg
))
4392 fprintf (file
, ", ");
4393 arg
= TREE_CHAIN (arg
);
4395 fprintf (file
, ")\n");
4397 if (flags
& TDF_DETAILS
)
4398 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4399 if (flags
& TDF_RAW
)
4401 dump_node (fn
, TDF_SLIM
| flags
, file
);
4405 /* When GIMPLE is lowered, the variables are no longer available in
4406 BIND_EXPRs, so display them separately. */
4407 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4409 ignore_topmost_bind
= true;
4411 fprintf (file
, "{\n");
4412 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4414 var
= TREE_VALUE (vars
);
4416 print_generic_decl (file
, var
, flags
);
4417 fprintf (file
, "\n");
4423 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4425 /* Make a CFG based dump. */
4426 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4427 if (!ignore_topmost_bind
)
4428 fprintf (file
, "{\n");
4430 if (any_var
&& n_basic_blocks
)
4431 fprintf (file
, "\n");
4434 dump_generic_bb (file
, bb
, 2, flags
);
4436 fprintf (file
, "}\n");
4437 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4443 /* Make a tree based dump. */
4444 chain
= DECL_SAVED_TREE (fn
);
4446 if (TREE_CODE (chain
) == BIND_EXPR
)
4448 if (ignore_topmost_bind
)
4450 chain
= BIND_EXPR_BODY (chain
);
4458 if (!ignore_topmost_bind
)
4459 fprintf (file
, "{\n");
4464 fprintf (file
, "\n");
4466 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4467 if (ignore_topmost_bind
)
4468 fprintf (file
, "}\n");
4471 fprintf (file
, "\n\n");
4475 /* Pretty print of the loops intermediate representation. */
4476 static void print_loop (FILE *, struct loop
*, int);
4477 static void print_pred_bbs (FILE *, basic_block bb
);
4478 static void print_succ_bbs (FILE *, basic_block bb
);
4481 /* Print the predecessors indexes of edge E on FILE. */
4484 print_pred_bbs (FILE *file
, basic_block bb
)
4489 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4490 fprintf (file
, "bb_%d", e
->src
->index
);
4494 /* Print the successors indexes of edge E on FILE. */
4497 print_succ_bbs (FILE *file
, basic_block bb
)
4502 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4503 fprintf (file
, "bb_%d", e
->src
->index
);
4507 /* Pretty print LOOP on FILE, indented INDENT spaces. */
4510 print_loop (FILE *file
, struct loop
*loop
, int indent
)
4518 s_indent
= (char *) alloca ((size_t) indent
+ 1);
4519 memset ((void *) s_indent
, ' ', (size_t) indent
);
4520 s_indent
[indent
] = '\0';
4522 /* Print the loop's header. */
4523 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
4525 /* Print the loop's body. */
4526 fprintf (file
, "%s{\n", s_indent
);
4528 if (bb
->loop_father
== loop
)
4530 /* Print the basic_block's header. */
4531 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
4532 print_pred_bbs (file
, bb
);
4533 fprintf (file
, "}, succs = {");
4534 print_succ_bbs (file
, bb
);
4535 fprintf (file
, "})\n");
4537 /* Print the basic_block's body. */
4538 fprintf (file
, "%s {\n", s_indent
);
4539 tree_dump_bb (bb
, file
, indent
+ 4);
4540 fprintf (file
, "%s }\n", s_indent
);
4543 print_loop (file
, loop
->inner
, indent
+ 2);
4544 fprintf (file
, "%s}\n", s_indent
);
4545 print_loop (file
, loop
->next
, indent
);
4549 /* Follow a CFG edge from the entry point of the program, and on entry
4550 of a loop, pretty print the loop structure on FILE. */
4553 print_loop_ir (FILE *file
)
4557 bb
= BASIC_BLOCK (0);
4558 if (bb
&& bb
->loop_father
)
4559 print_loop (file
, bb
->loop_father
, 0);
4563 /* Debugging loops structure at tree level. */
4566 debug_loop_ir (void)
4568 print_loop_ir (stderr
);
4572 /* Return true if BB ends with a call, possibly followed by some
4573 instructions that must stay with the call. Return false,
4577 tree_block_ends_with_call_p (basic_block bb
)
4579 block_stmt_iterator bsi
= bsi_last (bb
);
4580 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
4584 /* Return true if BB ends with a conditional branch. Return false,
4588 tree_block_ends_with_condjump_p (basic_block bb
)
4590 tree stmt
= last_stmt (bb
);
4591 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
4595 /* Return true if we need to add fake edge to exit at statement T.
4596 Helper function for tree_flow_call_edges_add. */
4599 need_fake_edge_p (tree t
)
4603 /* NORETURN and LONGJMP calls already have an edge to exit.
4604 CONST and PURE calls do not need one.
4605 We don't currently check for CONST and PURE here, although
4606 it would be a good idea, because those attributes are
4607 figured out from the RTL in mark_constant_function, and
4608 the counter incrementation code from -fprofile-arcs
4609 leads to different results from -fbranch-probabilities. */
4610 call
= get_call_expr_in (t
);
4612 && !(call_expr_flags (call
) & ECF_NORETURN
))
4615 if (TREE_CODE (t
) == ASM_EXPR
4616 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
4623 /* Add fake edges to the function exit for any non constant and non
4624 noreturn calls, volatile inline assembly in the bitmap of blocks
4625 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
4626 the number of blocks that were split.
4628 The goal is to expose cases in which entering a basic block does
4629 not imply that all subsequent instructions must be executed. */
4632 tree_flow_call_edges_add (sbitmap blocks
)
4635 int blocks_split
= 0;
4636 int last_bb
= last_basic_block
;
4637 bool check_last_block
= false;
4639 if (n_basic_blocks
== 0)
4643 check_last_block
= true;
4645 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
4647 /* In the last basic block, before epilogue generation, there will be
4648 a fallthru edge to EXIT. Special care is required if the last insn
4649 of the last basic block is a call because make_edge folds duplicate
4650 edges, which would result in the fallthru edge also being marked
4651 fake, which would result in the fallthru edge being removed by
4652 remove_fake_edges, which would result in an invalid CFG.
4654 Moreover, we can't elide the outgoing fake edge, since the block
4655 profiler needs to take this into account in order to solve the minimal
4656 spanning tree in the case that the call doesn't return.
4658 Handle this by adding a dummy instruction in a new last basic block. */
4659 if (check_last_block
)
4661 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
4662 block_stmt_iterator bsi
= bsi_last (bb
);
4664 if (!bsi_end_p (bsi
))
4667 if (need_fake_edge_p (t
))
4671 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4674 bsi_insert_on_edge (e
, build_empty_stmt ());
4675 bsi_commit_edge_inserts ();
4680 /* Now add fake edges to the function exit for any non constant
4681 calls since there is no way that we can determine if they will
4683 for (i
= 0; i
< last_bb
; i
++)
4685 basic_block bb
= BASIC_BLOCK (i
);
4686 block_stmt_iterator bsi
;
4687 tree stmt
, last_stmt
;
4692 if (blocks
&& !TEST_BIT (blocks
, i
))
4695 bsi
= bsi_last (bb
);
4696 if (!bsi_end_p (bsi
))
4698 last_stmt
= bsi_stmt (bsi
);
4701 stmt
= bsi_stmt (bsi
);
4702 if (need_fake_edge_p (stmt
))
4705 /* The handling above of the final block before the
4706 epilogue should be enough to verify that there is
4707 no edge to the exit block in CFG already.
4708 Calling make_edge in such case would cause us to
4709 mark that edge as fake and remove it later. */
4710 #ifdef ENABLE_CHECKING
4711 if (stmt
== last_stmt
)
4713 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4714 gcc_assert (e
== NULL
);
4718 /* Note that the following may create a new basic block
4719 and renumber the existing basic blocks. */
4720 if (stmt
!= last_stmt
)
4722 e
= split_block (bb
, stmt
);
4726 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
4730 while (!bsi_end_p (bsi
));
4735 verify_flow_info ();
4737 return blocks_split
;
4741 tree_purge_dead_eh_edges (basic_block bb
)
4743 bool changed
= false;
4746 tree stmt
= last_stmt (bb
);
4748 if (stmt
&& tree_can_throw_internal (stmt
))
4751 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
4753 if (e
->flags
& EDGE_EH
)
4762 /* Removal of dead EH edges might change dominators of not
4763 just immediate successors. E.g. when bb1 is changed so that
4764 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
4765 eh edges purged by this function in:
4777 idom(bb5) must be recomputed. For now just free the dominance
4780 free_dominance_info (CDI_DOMINATORS
);
4786 tree_purge_all_dead_eh_edges (bitmap blocks
)
4788 bool changed
= false;
4792 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
4794 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
4800 /* This function is called whenever a new edge is created or
4804 tree_execute_on_growing_pred (edge e
)
4806 basic_block bb
= e
->dest
;
4809 reserve_phi_args_for_new_edge (bb
);
4812 /* This function is called immediately before edge E is removed from
4813 the edge vector E->dest->preds. */
4816 tree_execute_on_shrinking_pred (edge e
)
4818 if (phi_nodes (e
->dest
))
4819 remove_phi_args (e
);
4822 /*---------------------------------------------------------------------------
4823 Helper functions for Loop versioning
4824 ---------------------------------------------------------------------------*/
4826 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
4827 of 'first'. Both of them are dominated by 'new_head' basic block. When
4828 'new_head' was created by 'second's incoming edge it received phi arguments
4829 on the edge by split_edge(). Later, additional edge 'e' was created to
4830 connect 'new_head' and 'first'. Now this routine adds phi args on this
4831 additional edge 'e' that new_head to second edge received as part of edge
4836 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
4837 basic_block new_head
, edge e
)
4840 edge e2
= find_edge (new_head
, second
);
4842 /* Because NEW_HEAD has been created by splitting SECOND's incoming
4843 edge, we should always have an edge from NEW_HEAD to SECOND. */
4844 gcc_assert (e2
!= NULL
);
4846 /* Browse all 'second' basic block phi nodes and add phi args to
4847 edge 'e' for 'first' head. PHI args are always in correct order. */
4849 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
4851 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
4853 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
4854 add_phi_arg (phi1
, def
, e
);
4858 /* Adds a if else statement to COND_BB with condition COND_EXPR.
4859 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
4860 the destination of the ELSE part. */
4862 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
4863 basic_block cond_bb
, void *cond_e
)
4865 block_stmt_iterator bsi
;
4866 tree goto1
= NULL_TREE
;
4867 tree goto2
= NULL_TREE
;
4868 tree new_cond_expr
= NULL_TREE
;
4869 tree cond_expr
= (tree
) cond_e
;
4872 /* Build new conditional expr */
4873 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
4874 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
4875 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
4877 /* Add new cond in cond_bb. */
4878 bsi
= bsi_start (cond_bb
);
4879 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
4880 /* Adjust edges appropriately to connect new head with first head
4881 as well as second head. */
4882 e0
= single_succ_edge (cond_bb
);
4883 e0
->flags
&= ~EDGE_FALLTHRU
;
4884 e0
->flags
|= EDGE_FALSE_VALUE
;
4887 struct cfg_hooks tree_cfg_hooks
= {
4889 tree_verify_flow_info
,
4890 tree_dump_bb
, /* dump_bb */
4891 create_bb
, /* create_basic_block */
4892 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
4893 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
4894 remove_bb
, /* delete_basic_block */
4895 tree_split_block
, /* split_block */
4896 tree_move_block_after
, /* move_block_after */
4897 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
4898 tree_merge_blocks
, /* merge_blocks */
4899 tree_predict_edge
, /* predict_edge */
4900 tree_predicted_by_p
, /* predicted_by_p */
4901 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
4902 tree_duplicate_bb
, /* duplicate_block */
4903 tree_split_edge
, /* split_edge */
4904 tree_make_forwarder_block
, /* make_forward_block */
4905 NULL
, /* tidy_fallthru_edge */
4906 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
4907 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
4908 tree_flow_call_edges_add
, /* flow_call_edges_add */
4909 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
4910 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
4911 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
4912 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
4913 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
4914 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
4915 flush_pending_stmts
/* flush_pending_stmts */
4919 /* Split all critical edges. */
4922 split_critical_edges (void)
4928 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
4929 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
4930 mappings around the calls to split_edge. */
4931 start_recording_case_labels ();
4934 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4935 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
4940 end_recording_case_labels ();
4943 struct tree_opt_pass pass_split_crit_edges
=
4945 "crited", /* name */
4947 split_critical_edges
, /* execute */
4950 0, /* static_pass_number */
4951 TV_TREE_SPLIT_EDGES
, /* tv_id */
4952 PROP_cfg
, /* properties required */
4953 PROP_no_crit_edges
, /* properties_provided */
4954 0, /* properties_destroyed */
4955 0, /* todo_flags_start */
4956 TODO_dump_func
, /* todo_flags_finish */
4961 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
4962 a temporary, make sure and register it to be renamed if necessary,
4963 and finally return the temporary. Put the statements to compute
4964 EXP before the current statement in BSI. */
4967 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
4969 tree t
, new_stmt
, orig_stmt
;
4971 if (is_gimple_val (exp
))
4974 t
= make_rename_temp (type
, NULL
);
4975 new_stmt
= build (MODIFY_EXPR
, type
, t
, exp
);
4977 orig_stmt
= bsi_stmt (*bsi
);
4978 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
4979 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
4981 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
4986 /* Build a ternary operation and gimplify it. Emit code before BSI.
4987 Return the gimple_val holding the result. */
4990 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
4991 tree type
, tree a
, tree b
, tree c
)
4995 ret
= fold_build3 (code
, type
, a
, b
, c
);
4998 return gimplify_val (bsi
, type
, ret
);
5001 /* Build a binary operation and gimplify it. Emit code before BSI.
5002 Return the gimple_val holding the result. */
5005 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5006 tree type
, tree a
, tree b
)
5010 ret
= fold_build2 (code
, type
, a
, b
);
5013 return gimplify_val (bsi
, type
, ret
);
5016 /* Build a unary operation and gimplify it. Emit code before BSI.
5017 Return the gimple_val holding the result. */
5020 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5025 ret
= fold_build1 (code
, type
, a
);
5028 return gimplify_val (bsi
, type
, ret
);
5033 /* Emit return warnings. */
5036 execute_warn_function_return (void)
5038 #ifdef USE_MAPPED_LOCATION
5039 source_location location
;
5047 /* If we have a path to EXIT, then we do return. */
5048 if (TREE_THIS_VOLATILE (cfun
->decl
)
5049 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5051 #ifdef USE_MAPPED_LOCATION
5052 location
= UNKNOWN_LOCATION
;
5056 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5058 last
= last_stmt (e
->src
);
5059 if (TREE_CODE (last
) == RETURN_EXPR
5060 #ifdef USE_MAPPED_LOCATION
5061 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5063 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5067 #ifdef USE_MAPPED_LOCATION
5068 if (location
== UNKNOWN_LOCATION
)
5069 location
= cfun
->function_end_locus
;
5070 warning (0, "%H%<noreturn%> function does return", &location
);
5073 locus
= &cfun
->function_end_locus
;
5074 warning (0, "%H%<noreturn%> function does return", locus
);
5078 /* If we see "return;" in some basic block, then we do reach the end
5079 without returning a value. */
5080 else if (warn_return_type
5081 && !TREE_NO_WARNING (cfun
->decl
)
5082 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5083 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5085 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5087 tree last
= last_stmt (e
->src
);
5088 if (TREE_CODE (last
) == RETURN_EXPR
5089 && TREE_OPERAND (last
, 0) == NULL
)
5091 #ifdef USE_MAPPED_LOCATION
5092 location
= EXPR_LOCATION (last
);
5093 if (location
== UNKNOWN_LOCATION
)
5094 location
= cfun
->function_end_locus
;
5095 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5097 locus
= EXPR_LOCUS (last
);
5099 locus
= &cfun
->function_end_locus
;
5100 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5102 TREE_NO_WARNING (cfun
->decl
) = 1;
5110 /* Given a basic block B which ends with a conditional and has
5111 precisely two successors, determine which of the edges is taken if
5112 the conditional is true and which is taken if the conditional is
5113 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5116 extract_true_false_edges_from_block (basic_block b
,
5120 edge e
= EDGE_SUCC (b
, 0);
5122 if (e
->flags
& EDGE_TRUE_VALUE
)
5125 *false_edge
= EDGE_SUCC (b
, 1);
5130 *true_edge
= EDGE_SUCC (b
, 1);
5134 struct tree_opt_pass pass_warn_function_return
=
5138 execute_warn_function_return
, /* execute */
5141 0, /* static_pass_number */
5143 PROP_cfg
, /* properties_required */
5144 0, /* properties_provided */
5145 0, /* properties_destroyed */
5146 0, /* todo_flags_start */
5147 0, /* todo_flags_finish */
5151 /* Emit noreturn warnings. */
5154 execute_warn_function_noreturn (void)
5156 if (warn_missing_noreturn
5157 && !TREE_THIS_VOLATILE (cfun
->decl
)
5158 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5159 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5160 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5161 "for attribute %<noreturn%>",
5165 struct tree_opt_pass pass_warn_function_noreturn
=
5169 execute_warn_function_noreturn
, /* execute */
5172 0, /* static_pass_number */
5174 PROP_cfg
, /* properties_required */
5175 0, /* properties_provided */
5176 0, /* properties_destroyed */
5177 0, /* todo_flags_start */
5178 0, /* todo_flags_finish */