2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-inline.h"
32 #include "tree-flow.h"
34 #include "tree-dump.h"
38 #include "tree-iterator.h"
40 #include "alloc-pool.h"
42 #include "tree-pass.h"
45 #include "langhooks.h"
47 #include "tree-ssa-sccvn.h"
48 #include "tree-scalar-evolution.h"
54 1. Avail sets can be shared by making an avail_find_leader that
55 walks up the dominator tree and looks in those avail sets.
56 This might affect code optimality, it's unclear right now.
57 2. Strength reduction can be performed by anticipating expressions
58 we can repair later on.
59 3. We can do back-substitution or smarter value numbering to catch
60 commutative expressions split up over multiple statements.
63 /* For ease of terminology, "expression node" in the below refers to
64 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
65 represent the actual statement containing the expressions we care about,
66 and we cache the value number by putting it in the expression. */
70 First we walk the statements to generate the AVAIL sets, the
71 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
72 generation of values/expressions by a given block. We use them
73 when computing the ANTIC sets. The AVAIL sets consist of
74 SSA_NAME's that represent values, so we know what values are
75 available in what blocks. AVAIL is a forward dataflow problem. In
76 SSA, values are never killed, so we don't need a kill set, or a
77 fixpoint iteration, in order to calculate the AVAIL sets. In
78 traditional parlance, AVAIL sets tell us the downsafety of the
81 Next, we generate the ANTIC sets. These sets represent the
82 anticipatable expressions. ANTIC is a backwards dataflow
83 problem. An expression is anticipatable in a given block if it could
84 be generated in that block. This means that if we had to perform
85 an insertion in that block, of the value of that expression, we
86 could. Calculating the ANTIC sets requires phi translation of
87 expressions, because the flow goes backwards through phis. We must
88 iterate to a fixpoint of the ANTIC sets, because we have a kill
89 set. Even in SSA form, values are not live over the entire
90 function, only from their definition point onwards. So we have to
91 remove values from the ANTIC set once we go past the definition
92 point of the leaders that make them up.
93 compute_antic/compute_antic_aux performs this computation.
95 Third, we perform insertions to make partially redundant
96 expressions fully redundant.
98 An expression is partially redundant (excluding partial
101 1. It is AVAIL in some, but not all, of the predecessors of a
103 2. It is ANTIC in all the predecessors.
105 In order to make it fully redundant, we insert the expression into
106 the predecessors where it is not available, but is ANTIC.
108 For the partial anticipation case, we only perform insertion if it
109 is partially anticipated in some block, and fully available in all
112 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
113 performs these steps.
115 Fourth, we eliminate fully redundant expressions.
116 This is a simple statement walk that replaces redundant
117 calculations with the now available values. */
119 /* Representations of value numbers:
121 Value numbers are represented by a representative SSA_NAME. We
122 will create fake SSA_NAME's in situations where we need a
123 representative but do not have one (because it is a complex
124 expression). In order to facilitate storing the value numbers in
125 bitmaps, and keep the number of wasted SSA_NAME's down, we also
126 associate a value_id with each value number, and create full blown
127 ssa_name's only where we actually need them (IE in operands of
128 existing expressions).
130 Theoretically you could replace all the value_id's with
131 SSA_NAME_VERSION, but this would allocate a large number of
132 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
133 It would also require an additional indirection at each point we
136 /* Representation of expressions on value numbers:
138 Expressions consisting of value numbers are represented the same
139 way as our VN internally represents them, with an additional
140 "pre_expr" wrapping around them in order to facilitate storing all
141 of the expressions in the same sets. */
143 /* Representation of sets:
145 The dataflow sets do not need to be sorted in any particular order
146 for the majority of their lifetime, are simply represented as two
147 bitmaps, one that keeps track of values present in the set, and one
148 that keeps track of expressions present in the set.
150 When we need them in topological order, we produce it on demand by
151 transforming the bitmap into an array and sorting it into topo
154 /* Type of expression, used to know which member of the PRE_EXPR union
165 typedef union pre_expr_union_d
170 vn_reference_t reference
;
173 typedef struct pre_expr_d
175 enum pre_expr_kind kind
;
180 #define PRE_EXPR_NAME(e) (e)->u.name
181 #define PRE_EXPR_NARY(e) (e)->u.nary
182 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
183 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
186 pre_expr_eq (const void *p1
, const void *p2
)
188 const struct pre_expr_d
*e1
= (const struct pre_expr_d
*) p1
;
189 const struct pre_expr_d
*e2
= (const struct pre_expr_d
*) p2
;
191 if (e1
->kind
!= e2
->kind
)
197 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1
),
198 PRE_EXPR_CONSTANT (e2
));
200 return PRE_EXPR_NAME (e1
) == PRE_EXPR_NAME (e2
);
202 return vn_nary_op_eq (PRE_EXPR_NARY (e1
), PRE_EXPR_NARY (e2
));
204 return vn_reference_eq (PRE_EXPR_REFERENCE (e1
),
205 PRE_EXPR_REFERENCE (e2
));
212 pre_expr_hash (const void *p1
)
214 const struct pre_expr_d
*e
= (const struct pre_expr_d
*) p1
;
218 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e
));
220 return iterative_hash_hashval_t (SSA_NAME_VERSION (PRE_EXPR_NAME (e
)), 0);
222 return PRE_EXPR_NARY (e
)->hashcode
;
224 return PRE_EXPR_REFERENCE (e
)->hashcode
;
231 /* Next global expression id number. */
232 static unsigned int next_expression_id
;
234 /* Mapping from expression to id number we can use in bitmap sets. */
235 DEF_VEC_P (pre_expr
);
236 DEF_VEC_ALLOC_P (pre_expr
, heap
);
237 static VEC(pre_expr
, heap
) *expressions
;
238 static htab_t expression_to_id
;
240 /* Allocate an expression id for EXPR. */
242 static inline unsigned int
243 alloc_expression_id (pre_expr expr
)
246 /* Make sure we won't overflow. */
247 gcc_assert (next_expression_id
+ 1 > next_expression_id
);
248 expr
->id
= next_expression_id
++;
249 VEC_safe_push (pre_expr
, heap
, expressions
, expr
);
250 slot
= htab_find_slot (expression_to_id
, expr
, INSERT
);
253 return next_expression_id
- 1;
256 /* Return the expression id for tree EXPR. */
258 static inline unsigned int
259 get_expression_id (const pre_expr expr
)
264 static inline unsigned int
265 lookup_expression_id (const pre_expr expr
)
269 slot
= htab_find_slot (expression_to_id
, expr
, NO_INSERT
);
272 return ((pre_expr
)*slot
)->id
;
275 /* Return the existing expression id for EXPR, or create one if one
276 does not exist yet. */
278 static inline unsigned int
279 get_or_alloc_expression_id (pre_expr expr
)
281 unsigned int id
= lookup_expression_id (expr
);
283 return alloc_expression_id (expr
);
284 return expr
->id
= id
;
287 /* Return the expression that has expression id ID */
289 static inline pre_expr
290 expression_for_id (unsigned int id
)
292 return VEC_index (pre_expr
, expressions
, id
);
295 /* Free the expression id field in all of our expressions,
296 and then destroy the expressions array. */
299 clear_expression_ids (void)
301 VEC_free (pre_expr
, heap
, expressions
);
304 static alloc_pool pre_expr_pool
;
306 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
309 get_or_alloc_expr_for_name (tree name
)
311 pre_expr result
= (pre_expr
) pool_alloc (pre_expr_pool
);
312 unsigned int result_id
;
316 PRE_EXPR_NAME (result
) = name
;
317 result_id
= lookup_expression_id (result
);
320 pool_free (pre_expr_pool
, result
);
321 result
= expression_for_id (result_id
);
324 get_or_alloc_expression_id (result
);
328 static bool in_fre
= false;
330 /* An unordered bitmap set. One bitmap tracks values, the other,
332 typedef struct bitmap_set
338 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
339 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
341 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
342 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
344 /* Mapping from value id to expressions with that value_id. */
345 DEF_VEC_P (bitmap_set_t
);
346 DEF_VEC_ALLOC_P (bitmap_set_t
, heap
);
347 static VEC(bitmap_set_t
, heap
) *value_expressions
;
349 /* Sets that we need to keep track of. */
350 typedef struct bb_bitmap_sets
352 /* The EXP_GEN set, which represents expressions/values generated in
354 bitmap_set_t exp_gen
;
356 /* The PHI_GEN set, which represents PHI results generated in a
358 bitmap_set_t phi_gen
;
360 /* The TMP_GEN set, which represents results/temporaries generated
361 in a basic block. IE the LHS of an expression. */
362 bitmap_set_t tmp_gen
;
364 /* The AVAIL_OUT set, which represents which values are available in
365 a given basic block. */
366 bitmap_set_t avail_out
;
368 /* The ANTIC_IN set, which represents which values are anticipatable
369 in a given basic block. */
370 bitmap_set_t antic_in
;
372 /* The PA_IN set, which represents which values are
373 partially anticipatable in a given basic block. */
376 /* The NEW_SETS set, which is used during insertion to augment the
377 AVAIL_OUT set of blocks with the new insertions performed during
378 the current iteration. */
379 bitmap_set_t new_sets
;
381 /* A cache for value_dies_in_block_x. */
384 /* True if we have visited this block during ANTIC calculation. */
385 unsigned int visited
:1;
387 /* True we have deferred processing this block during ANTIC
388 calculation until its successor is processed. */
389 unsigned int deferred
: 1;
392 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
393 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
394 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
395 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
396 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
397 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
398 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
399 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
400 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
401 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
404 /* Maximal set of values, used to initialize the ANTIC problem, which
405 is an intersection problem. */
406 static bitmap_set_t maximal_set
;
408 /* Basic block list in postorder. */
409 static int *postorder
;
411 /* This structure is used to keep track of statistics on what
412 optimization PRE was able to perform. */
415 /* The number of RHS computations eliminated by PRE. */
418 /* The number of new expressions/temporaries generated by PRE. */
421 /* The number of inserts found due to partial anticipation */
424 /* The number of new PHI nodes added by PRE. */
427 /* The number of values found constant. */
432 static bool do_partial_partial
;
433 static pre_expr
bitmap_find_leader (bitmap_set_t
, unsigned int, gimple
);
434 static void bitmap_value_insert_into_set (bitmap_set_t
, pre_expr
);
435 static void bitmap_value_replace_in_set (bitmap_set_t
, pre_expr
);
436 static void bitmap_set_copy (bitmap_set_t
, bitmap_set_t
);
437 static bool bitmap_set_contains_value (bitmap_set_t
, unsigned int);
438 static void bitmap_insert_into_set (bitmap_set_t
, pre_expr
);
439 static void bitmap_insert_into_set_1 (bitmap_set_t
, pre_expr
, bool);
440 static bitmap_set_t
bitmap_set_new (void);
441 static tree
create_expression_by_pieces (basic_block
, pre_expr
, gimple_seq
*,
443 static tree
find_or_generate_expression (basic_block
, pre_expr
, gimple_seq
*,
445 static unsigned int get_expr_value_id (pre_expr
);
447 /* We can add and remove elements and entries to and from sets
448 and hash tables, so we use alloc pools for them. */
450 static alloc_pool bitmap_set_pool
;
451 static bitmap_obstack grand_bitmap_obstack
;
453 /* To avoid adding 300 temporary variables when we only need one, we
454 only create one temporary variable, on demand, and build ssa names
455 off that. We do have to change the variable if the types don't
456 match the current variable's type. */
458 static tree storetemp
;
459 static tree prephitemp
;
461 /* Set of blocks with statements that have had its EH information
463 static bitmap need_eh_cleanup
;
465 /* Which expressions have been seen during a given phi translation. */
466 static bitmap seen_during_translate
;
468 /* The phi_translate_table caches phi translations for a given
469 expression and predecessor. */
471 static htab_t phi_translate_table
;
473 /* A three tuple {e, pred, v} used to cache phi translations in the
474 phi_translate_table. */
476 typedef struct expr_pred_trans_d
478 /* The expression. */
481 /* The predecessor block along which we translated the expression. */
484 /* The value that resulted from the translation. */
487 /* The hashcode for the expression, pred pair. This is cached for
490 } *expr_pred_trans_t
;
491 typedef const struct expr_pred_trans_d
*const_expr_pred_trans_t
;
493 /* Return the hash value for a phi translation table entry. */
496 expr_pred_trans_hash (const void *p
)
498 const_expr_pred_trans_t
const ve
= (const_expr_pred_trans_t
) p
;
502 /* Return true if two phi translation table entries are the same.
503 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
506 expr_pred_trans_eq (const void *p1
, const void *p2
)
508 const_expr_pred_trans_t
const ve1
= (const_expr_pred_trans_t
) p1
;
509 const_expr_pred_trans_t
const ve2
= (const_expr_pred_trans_t
) p2
;
510 basic_block b1
= ve1
->pred
;
511 basic_block b2
= ve2
->pred
;
513 /* If they are not translations for the same basic block, they can't
517 return pre_expr_eq (ve1
->e
, ve2
->e
);
520 /* Search in the phi translation table for the translation of
521 expression E in basic block PRED.
522 Return the translated value, if found, NULL otherwise. */
524 static inline pre_expr
525 phi_trans_lookup (pre_expr e
, basic_block pred
)
528 struct expr_pred_trans_d ept
;
532 ept
.hashcode
= iterative_hash_hashval_t (pre_expr_hash (e
), pred
->index
);
533 slot
= htab_find_slot_with_hash (phi_translate_table
, &ept
, ept
.hashcode
,
538 return ((expr_pred_trans_t
) *slot
)->v
;
542 /* Add the tuple mapping from {expression E, basic block PRED} to
543 value V, to the phi translation table. */
546 phi_trans_add (pre_expr e
, pre_expr v
, basic_block pred
)
549 expr_pred_trans_t new_pair
= XNEW (struct expr_pred_trans_d
);
551 new_pair
->pred
= pred
;
553 new_pair
->hashcode
= iterative_hash_hashval_t (pre_expr_hash (e
),
556 slot
= htab_find_slot_with_hash (phi_translate_table
, new_pair
,
557 new_pair
->hashcode
, INSERT
);
560 *slot
= (void *) new_pair
;
564 /* Add expression E to the expression set of value id V. */
567 add_to_value (unsigned int v
, pre_expr e
)
571 gcc_assert (get_expr_value_id (e
) == v
);
573 if (v
>= VEC_length (bitmap_set_t
, value_expressions
))
575 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
579 set
= VEC_index (bitmap_set_t
, value_expressions
, v
);
582 set
= bitmap_set_new ();
583 VEC_replace (bitmap_set_t
, value_expressions
, v
, set
);
586 bitmap_insert_into_set_1 (set
, e
, true);
589 /* Create a new bitmap set and return it. */
592 bitmap_set_new (void)
594 bitmap_set_t ret
= (bitmap_set_t
) pool_alloc (bitmap_set_pool
);
595 ret
->expressions
= BITMAP_ALLOC (&grand_bitmap_obstack
);
596 ret
->values
= BITMAP_ALLOC (&grand_bitmap_obstack
);
600 /* Return the value id for a PRE expression EXPR. */
603 get_expr_value_id (pre_expr expr
)
610 id
= get_constant_value_id (PRE_EXPR_CONSTANT (expr
));
613 id
= get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr
));
614 add_to_value (id
, expr
);
619 return VN_INFO (PRE_EXPR_NAME (expr
))->value_id
;
621 return PRE_EXPR_NARY (expr
)->value_id
;
623 return PRE_EXPR_REFERENCE (expr
)->value_id
;
629 /* Remove an expression EXPR from a bitmapped set. */
632 bitmap_remove_from_set (bitmap_set_t set
, pre_expr expr
)
634 unsigned int val
= get_expr_value_id (expr
);
635 if (!value_id_constant_p (val
))
637 bitmap_clear_bit (set
->values
, val
);
638 bitmap_clear_bit (set
->expressions
, get_expression_id (expr
));
643 bitmap_insert_into_set_1 (bitmap_set_t set
, pre_expr expr
,
644 bool allow_constants
)
646 unsigned int val
= get_expr_value_id (expr
);
647 if (allow_constants
|| !value_id_constant_p (val
))
649 /* We specifically expect this and only this function to be able to
650 insert constants into a set. */
651 bitmap_set_bit (set
->values
, val
);
652 bitmap_set_bit (set
->expressions
, get_or_alloc_expression_id (expr
));
656 /* Insert an expression EXPR into a bitmapped set. */
659 bitmap_insert_into_set (bitmap_set_t set
, pre_expr expr
)
661 bitmap_insert_into_set_1 (set
, expr
, false);
664 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
667 bitmap_set_copy (bitmap_set_t dest
, bitmap_set_t orig
)
669 bitmap_copy (dest
->expressions
, orig
->expressions
);
670 bitmap_copy (dest
->values
, orig
->values
);
674 /* Free memory used up by SET. */
676 bitmap_set_free (bitmap_set_t set
)
678 BITMAP_FREE (set
->expressions
);
679 BITMAP_FREE (set
->values
);
683 /* Generate an topological-ordered array of bitmap set SET. */
685 static VEC(pre_expr
, heap
) *
686 sorted_array_from_bitmap_set (bitmap_set_t set
)
689 bitmap_iterator bi
, bj
;
690 VEC(pre_expr
, heap
) *result
= NULL
;
692 FOR_EACH_VALUE_ID_IN_SET (set
, i
, bi
)
694 /* The number of expressions having a given value is usually
695 relatively small. Thus, rather than making a vector of all
696 the expressions and sorting it by value-id, we walk the values
697 and check in the reverse mapping that tells us what expressions
698 have a given value, to filter those in our set. As a result,
699 the expressions are inserted in value-id order, which means
702 If this is somehow a significant lose for some cases, we can
703 choose which set to walk based on the set size. */
704 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, i
);
705 FOR_EACH_EXPR_ID_IN_SET (exprset
, j
, bj
)
707 if (bitmap_bit_p (set
->expressions
, j
))
708 VEC_safe_push (pre_expr
, heap
, result
, expression_for_id (j
));
715 /* Perform bitmapped set operation DEST &= ORIG. */
718 bitmap_set_and (bitmap_set_t dest
, bitmap_set_t orig
)
725 bitmap temp
= BITMAP_ALLOC (&grand_bitmap_obstack
);
727 bitmap_and_into (dest
->values
, orig
->values
);
728 bitmap_copy (temp
, dest
->expressions
);
729 EXECUTE_IF_SET_IN_BITMAP (temp
, 0, i
, bi
)
731 pre_expr expr
= expression_for_id (i
);
732 unsigned int value_id
= get_expr_value_id (expr
);
733 if (!bitmap_bit_p (dest
->values
, value_id
))
734 bitmap_clear_bit (dest
->expressions
, i
);
740 /* Subtract all values and expressions contained in ORIG from DEST. */
743 bitmap_set_subtract (bitmap_set_t dest
, bitmap_set_t orig
)
745 bitmap_set_t result
= bitmap_set_new ();
749 bitmap_and_compl (result
->expressions
, dest
->expressions
,
752 FOR_EACH_EXPR_ID_IN_SET (result
, i
, bi
)
754 pre_expr expr
= expression_for_id (i
);
755 unsigned int value_id
= get_expr_value_id (expr
);
756 bitmap_set_bit (result
->values
, value_id
);
762 /* Subtract all the values in bitmap set B from bitmap set A. */
765 bitmap_set_subtract_values (bitmap_set_t a
, bitmap_set_t b
)
769 bitmap temp
= BITMAP_ALLOC (&grand_bitmap_obstack
);
771 bitmap_copy (temp
, a
->expressions
);
772 EXECUTE_IF_SET_IN_BITMAP (temp
, 0, i
, bi
)
774 pre_expr expr
= expression_for_id (i
);
775 if (bitmap_set_contains_value (b
, get_expr_value_id (expr
)))
776 bitmap_remove_from_set (a
, expr
);
782 /* Return true if bitmapped set SET contains the value VALUE_ID. */
785 bitmap_set_contains_value (bitmap_set_t set
, unsigned int value_id
)
787 if (value_id_constant_p (value_id
))
790 if (!set
|| bitmap_empty_p (set
->expressions
))
793 return bitmap_bit_p (set
->values
, value_id
);
797 bitmap_set_contains_expr (bitmap_set_t set
, const pre_expr expr
)
799 return bitmap_bit_p (set
->expressions
, get_expression_id (expr
));
802 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
805 bitmap_set_replace_value (bitmap_set_t set
, unsigned int lookfor
,
808 bitmap_set_t exprset
;
812 if (value_id_constant_p (lookfor
))
815 if (!bitmap_set_contains_value (set
, lookfor
))
818 /* The number of expressions having a given value is usually
819 significantly less than the total number of expressions in SET.
820 Thus, rather than check, for each expression in SET, whether it
821 has the value LOOKFOR, we walk the reverse mapping that tells us
822 what expressions have a given value, and see if any of those
823 expressions are in our set. For large testcases, this is about
824 5-10x faster than walking the bitmap. If this is somehow a
825 significant lose for some cases, we can choose which set to walk
826 based on the set size. */
827 exprset
= VEC_index (bitmap_set_t
, value_expressions
, lookfor
);
828 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
830 if (bitmap_bit_p (set
->expressions
, i
))
832 bitmap_clear_bit (set
->expressions
, i
);
833 bitmap_set_bit (set
->expressions
, get_expression_id (expr
));
839 /* Return true if two bitmap sets are equal. */
842 bitmap_set_equal (bitmap_set_t a
, bitmap_set_t b
)
844 return bitmap_equal_p (a
->values
, b
->values
);
847 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
848 and add it otherwise. */
851 bitmap_value_replace_in_set (bitmap_set_t set
, pre_expr expr
)
853 unsigned int val
= get_expr_value_id (expr
);
855 if (bitmap_set_contains_value (set
, val
))
856 bitmap_set_replace_value (set
, val
, expr
);
858 bitmap_insert_into_set (set
, expr
);
861 /* Insert EXPR into SET if EXPR's value is not already present in
865 bitmap_value_insert_into_set (bitmap_set_t set
, pre_expr expr
)
867 unsigned int val
= get_expr_value_id (expr
);
869 if (value_id_constant_p (val
))
872 if (!bitmap_set_contains_value (set
, val
))
873 bitmap_insert_into_set (set
, expr
);
876 /* Print out EXPR to outfile. */
879 print_pre_expr (FILE *outfile
, const pre_expr expr
)
884 print_generic_expr (outfile
, PRE_EXPR_CONSTANT (expr
), 0);
887 print_generic_expr (outfile
, PRE_EXPR_NAME (expr
), 0);
892 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
893 fprintf (outfile
, "{%s,", tree_code_name
[nary
->opcode
]);
894 for (i
= 0; i
< nary
->length
; i
++)
896 print_generic_expr (outfile
, nary
->op
[i
], 0);
897 if (i
!= (unsigned) nary
->length
- 1)
898 fprintf (outfile
, ",");
900 fprintf (outfile
, "}");
906 vn_reference_op_t vro
;
908 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
909 fprintf (outfile
, "{");
911 VEC_iterate (vn_reference_op_s
, ref
->operands
, i
, vro
);
914 bool closebrace
= false;
915 if (vro
->opcode
!= SSA_NAME
916 && TREE_CODE_CLASS (vro
->opcode
) != tcc_declaration
)
918 fprintf (outfile
, "%s", tree_code_name
[vro
->opcode
]);
921 fprintf (outfile
, "<");
927 print_generic_expr (outfile
, vro
->op0
, 0);
930 fprintf (outfile
, ",");
931 print_generic_expr (outfile
, vro
->op1
, 0);
935 fprintf (outfile
, ",");
936 print_generic_expr (outfile
, vro
->op2
, 0);
940 fprintf (outfile
, ">");
941 if (i
!= VEC_length (vn_reference_op_s
, ref
->operands
) - 1)
942 fprintf (outfile
, ",");
944 fprintf (outfile
, "}");
947 fprintf (outfile
, "@");
948 print_generic_expr (outfile
, ref
->vuse
, 0);
954 void debug_pre_expr (pre_expr
);
956 /* Like print_pre_expr but always prints to stderr. */
958 debug_pre_expr (pre_expr e
)
960 print_pre_expr (stderr
, e
);
961 fprintf (stderr
, "\n");
964 /* Print out SET to OUTFILE. */
967 print_bitmap_set (FILE *outfile
, bitmap_set_t set
,
968 const char *setname
, int blockindex
)
970 fprintf (outfile
, "%s[%d] := { ", setname
, blockindex
);
977 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
979 const pre_expr expr
= expression_for_id (i
);
982 fprintf (outfile
, ", ");
984 print_pre_expr (outfile
, expr
);
986 fprintf (outfile
, " (%04d)", get_expr_value_id (expr
));
989 fprintf (outfile
, " }\n");
992 void debug_bitmap_set (bitmap_set_t
);
995 debug_bitmap_set (bitmap_set_t set
)
997 print_bitmap_set (stderr
, set
, "debug", 0);
1000 /* Print out the expressions that have VAL to OUTFILE. */
1003 print_value_expressions (FILE *outfile
, unsigned int val
)
1005 bitmap_set_t set
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1009 sprintf (s
, "%04d", val
);
1010 print_bitmap_set (outfile
, set
, s
, 0);
1016 debug_value_expressions (unsigned int val
)
1018 print_value_expressions (stderr
, val
);
1021 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1025 get_or_alloc_expr_for_constant (tree constant
)
1027 unsigned int result_id
;
1028 unsigned int value_id
;
1029 pre_expr newexpr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1030 newexpr
->kind
= CONSTANT
;
1031 PRE_EXPR_CONSTANT (newexpr
) = constant
;
1032 result_id
= lookup_expression_id (newexpr
);
1035 pool_free (pre_expr_pool
, newexpr
);
1036 newexpr
= expression_for_id (result_id
);
1039 value_id
= get_or_alloc_constant_value_id (constant
);
1040 get_or_alloc_expression_id (newexpr
);
1041 add_to_value (value_id
, newexpr
);
1045 /* Given a value id V, find the actual tree representing the constant
1046 value if there is one, and return it. Return NULL if we can't find
1050 get_constant_for_value_id (unsigned int v
)
1052 if (value_id_constant_p (v
))
1056 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, v
);
1058 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
1060 pre_expr expr
= expression_for_id (i
);
1061 if (expr
->kind
== CONSTANT
)
1062 return PRE_EXPR_CONSTANT (expr
);
1068 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1069 Currently only supports constants and SSA_NAMES. */
1071 get_or_alloc_expr_for (tree t
)
1073 if (TREE_CODE (t
) == SSA_NAME
)
1074 return get_or_alloc_expr_for_name (t
);
1075 else if (is_gimple_min_invariant (t
)
1076 || TREE_CODE (t
) == EXC_PTR_EXPR
1077 || TREE_CODE (t
) == FILTER_EXPR
)
1078 return get_or_alloc_expr_for_constant (t
);
1081 /* More complex expressions can result from SCCVN expression
1082 simplification that inserts values for them. As they all
1083 do not have VOPs the get handled by the nary ops struct. */
1084 vn_nary_op_t result
;
1085 unsigned int result_id
;
1086 vn_nary_op_lookup (t
, &result
);
1089 pre_expr e
= (pre_expr
) pool_alloc (pre_expr_pool
);
1091 PRE_EXPR_NARY (e
) = result
;
1092 result_id
= lookup_expression_id (e
);
1095 pool_free (pre_expr_pool
, e
);
1096 e
= expression_for_id (result_id
);
1099 alloc_expression_id (e
);
1106 /* Return the folded version of T if T, when folded, is a gimple
1107 min_invariant. Otherwise, return T. */
1110 fully_constant_expression (pre_expr e
)
1118 vn_nary_op_t nary
= PRE_EXPR_NARY (e
);
1119 switch (TREE_CODE_CLASS (nary
->opcode
))
1121 case tcc_expression
:
1122 if (nary
->opcode
== TRUTH_NOT_EXPR
)
1124 if (nary
->opcode
!= TRUTH_AND_EXPR
1125 && nary
->opcode
!= TRUTH_OR_EXPR
1126 && nary
->opcode
!= TRUTH_XOR_EXPR
)
1130 case tcc_comparison
:
1132 /* We have to go from trees to pre exprs to value ids to
1134 tree naryop0
= nary
->op
[0];
1135 tree naryop1
= nary
->op
[1];
1137 if (!is_gimple_min_invariant (naryop0
))
1139 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1140 unsigned int vrep0
= get_expr_value_id (rep0
);
1141 tree const0
= get_constant_for_value_id (vrep0
);
1143 naryop0
= fold_convert (TREE_TYPE (naryop0
), const0
);
1145 if (!is_gimple_min_invariant (naryop1
))
1147 pre_expr rep1
= get_or_alloc_expr_for (naryop1
);
1148 unsigned int vrep1
= get_expr_value_id (rep1
);
1149 tree const1
= get_constant_for_value_id (vrep1
);
1151 naryop1
= fold_convert (TREE_TYPE (naryop1
), const1
);
1153 result
= fold_binary (nary
->opcode
, nary
->type
,
1155 if (result
&& is_gimple_min_invariant (result
))
1156 return get_or_alloc_expr_for_constant (result
);
1157 /* We might have simplified the expression to a
1158 SSA_NAME for example from x_1 * 1. But we cannot
1159 insert a PHI for x_1 unconditionally as x_1 might
1160 not be available readily. */
1164 if (nary
->opcode
!= REALPART_EXPR
1165 && nary
->opcode
!= IMAGPART_EXPR
1166 && nary
->opcode
!= VIEW_CONVERT_EXPR
)
1172 /* We have to go from trees to pre exprs to value ids to
1174 tree naryop0
= nary
->op
[0];
1175 tree const0
, result
;
1176 if (is_gimple_min_invariant (naryop0
))
1180 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1181 unsigned int vrep0
= get_expr_value_id (rep0
);
1182 const0
= get_constant_for_value_id (vrep0
);
1187 tree type1
= TREE_TYPE (nary
->op
[0]);
1188 const0
= fold_convert (type1
, const0
);
1189 result
= fold_unary (nary
->opcode
, nary
->type
, const0
);
1191 if (result
&& is_gimple_min_invariant (result
))
1192 return get_or_alloc_expr_for_constant (result
);
1201 vn_reference_t ref
= PRE_EXPR_REFERENCE (e
);
1202 VEC (vn_reference_op_s
, heap
) *operands
= ref
->operands
;
1203 vn_reference_op_t op
;
1205 /* Try to simplify the translated expression if it is
1206 a call to a builtin function with at most two arguments. */
1207 op
= VEC_index (vn_reference_op_s
, operands
, 0);
1208 if (op
->opcode
== CALL_EXPR
1209 && TREE_CODE (op
->op0
) == ADDR_EXPR
1210 && TREE_CODE (TREE_OPERAND (op
->op0
, 0)) == FUNCTION_DECL
1211 && DECL_BUILT_IN (TREE_OPERAND (op
->op0
, 0))
1212 && VEC_length (vn_reference_op_s
, operands
) >= 2
1213 && VEC_length (vn_reference_op_s
, operands
) <= 3)
1215 vn_reference_op_t arg0
, arg1
= NULL
;
1216 bool anyconst
= false;
1217 arg0
= VEC_index (vn_reference_op_s
, operands
, 1);
1218 if (VEC_length (vn_reference_op_s
, operands
) > 2)
1219 arg1
= VEC_index (vn_reference_op_s
, operands
, 2);
1220 if (TREE_CODE_CLASS (arg0
->opcode
) == tcc_constant
1221 || (arg0
->opcode
== ADDR_EXPR
1222 && is_gimple_min_invariant (arg0
->op0
)))
1225 && (TREE_CODE_CLASS (arg1
->opcode
) == tcc_constant
1226 || (arg1
->opcode
== ADDR_EXPR
1227 && is_gimple_min_invariant (arg1
->op0
))))
1231 tree folded
= build_call_expr (TREE_OPERAND (op
->op0
, 0),
1234 arg1
? arg1
->op0
: NULL
);
1236 && TREE_CODE (folded
) == NOP_EXPR
)
1237 folded
= TREE_OPERAND (folded
, 0);
1239 && is_gimple_min_invariant (folded
))
1240 return get_or_alloc_expr_for_constant (folded
);
1251 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1252 it has the value it would have in BLOCK. */
1255 translate_vuse_through_block (VEC (vn_reference_op_s
, heap
) *operands
,
1256 alias_set_type set
, tree type
, tree vuse
,
1257 basic_block phiblock
,
1260 gimple phi
= SSA_NAME_DEF_STMT (vuse
);
1263 if (gimple_bb (phi
) != phiblock
)
1266 if (gimple_code (phi
) == GIMPLE_PHI
)
1268 edge e
= find_edge (block
, phiblock
);
1269 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1272 if (!ao_ref_init_from_vn_reference (&ref
, set
, type
, operands
))
1275 /* Use the alias-oracle to find either the PHI node in this block,
1276 the first VUSE used in this block that is equivalent to vuse or
1277 the first VUSE which definition in this block kills the value. */
1278 while (!stmt_may_clobber_ref_p_1 (phi
, &ref
))
1280 vuse
= gimple_vuse (phi
);
1281 phi
= SSA_NAME_DEF_STMT (vuse
);
1282 if (gimple_bb (phi
) != phiblock
)
1284 if (gimple_code (phi
) == GIMPLE_PHI
)
1286 edge e
= find_edge (block
, phiblock
);
1287 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1294 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1295 SET2. This is used to avoid making a set consisting of the union
1296 of PA_IN and ANTIC_IN during insert. */
1298 static inline pre_expr
1299 find_leader_in_sets (unsigned int val
, bitmap_set_t set1
, bitmap_set_t set2
)
1303 result
= bitmap_find_leader (set1
, val
, NULL
);
1304 if (!result
&& set2
)
1305 result
= bitmap_find_leader (set2
, val
, NULL
);
1309 /* Get the tree type for our PRE expression e. */
1312 get_expr_type (const pre_expr e
)
1317 return TREE_TYPE (PRE_EXPR_NAME (e
));
1319 return TREE_TYPE (PRE_EXPR_CONSTANT (e
));
1321 return PRE_EXPR_REFERENCE (e
)->type
;
1323 return PRE_EXPR_NARY (e
)->type
;
1328 /* Get a representative SSA_NAME for a given expression.
1329 Since all of our sub-expressions are treated as values, we require
1330 them to be SSA_NAME's for simplicity.
1331 Prior versions of GVNPRE used to use "value handles" here, so that
1332 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1333 either case, the operands are really values (IE we do not expect
1334 them to be usable without finding leaders). */
1337 get_representative_for (const pre_expr e
)
1341 unsigned int value_id
= get_expr_value_id (e
);
1346 return PRE_EXPR_NAME (e
);
1348 return PRE_EXPR_CONSTANT (e
);
1352 /* Go through all of the expressions representing this value
1353 and pick out an SSA_NAME. */
1356 bitmap_set_t exprs
= VEC_index (bitmap_set_t
, value_expressions
,
1358 FOR_EACH_EXPR_ID_IN_SET (exprs
, i
, bi
)
1360 pre_expr rep
= expression_for_id (i
);
1361 if (rep
->kind
== NAME
)
1362 return PRE_EXPR_NAME (rep
);
1367 /* If we reached here we couldn't find an SSA_NAME. This can
1368 happen when we've discovered a value that has never appeared in
1369 the program as set to an SSA_NAME, most likely as the result of
1374 "Could not find SSA_NAME representative for expression:");
1375 print_pre_expr (dump_file
, e
);
1376 fprintf (dump_file
, "\n");
1379 exprtype
= get_expr_type (e
);
1381 /* Build and insert the assignment of the end result to the temporary
1382 that we will return. */
1383 if (!pretemp
|| exprtype
!= TREE_TYPE (pretemp
))
1385 pretemp
= create_tmp_var (exprtype
, "pretmp");
1386 get_var_ann (pretemp
);
1389 name
= make_ssa_name (pretemp
, gimple_build_nop ());
1390 VN_INFO_GET (name
)->value_id
= value_id
;
1391 if (e
->kind
== CONSTANT
)
1392 VN_INFO (name
)->valnum
= PRE_EXPR_CONSTANT (e
);
1394 VN_INFO (name
)->valnum
= name
;
1396 add_to_value (value_id
, get_or_alloc_expr_for_name (name
));
1399 fprintf (dump_file
, "Created SSA_NAME representative ");
1400 print_generic_expr (dump_file
, name
, 0);
1401 fprintf (dump_file
, " for expression:");
1402 print_pre_expr (dump_file
, e
);
1403 fprintf (dump_file
, "\n");
1412 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1413 the phis in PRED. SEEN is a bitmap saying which expression we have
1414 translated since we started translation of the toplevel expression.
1415 Return NULL if we can't find a leader for each part of the
1416 translated expression. */
1419 phi_translate_1 (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1420 basic_block pred
, basic_block phiblock
, bitmap seen
)
1422 pre_expr oldexpr
= expr
;
1428 if (value_id_constant_p (get_expr_value_id (expr
)))
1431 phitrans
= phi_trans_lookup (expr
, pred
);
1435 /* Prevent cycles when we have recursively dependent leaders. This
1436 can only happen when phi translating the maximal set. */
1439 unsigned int expr_id
= get_expression_id (expr
);
1440 if (bitmap_bit_p (seen
, expr_id
))
1442 bitmap_set_bit (seen
, expr_id
);
1447 /* Constants contain no values that need translation. */
1454 bool changed
= false;
1455 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1456 struct vn_nary_op_s newnary
;
1457 /* The NARY structure is only guaranteed to have been
1458 allocated to the nary->length operands. */
1459 memcpy (&newnary
, nary
, (sizeof (struct vn_nary_op_s
)
1460 - sizeof (tree
) * (4 - nary
->length
)));
1462 for (i
= 0; i
< newnary
.length
; i
++)
1464 if (TREE_CODE (newnary
.op
[i
]) != SSA_NAME
)
1468 unsigned int op_val_id
= VN_INFO (newnary
.op
[i
])->value_id
;
1469 pre_expr leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1470 pre_expr result
= phi_translate_1 (leader
, set1
, set2
,
1471 pred
, phiblock
, seen
);
1472 if (result
&& result
!= leader
)
1474 tree name
= get_representative_for (result
);
1477 newnary
.op
[i
] = name
;
1482 changed
|= newnary
.op
[i
] != nary
->op
[i
];
1489 tree result
= vn_nary_op_lookup_pieces (newnary
.length
,
1497 unsigned int new_val_id
;
1499 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1502 if (result
&& is_gimple_min_invariant (result
))
1503 return get_or_alloc_expr_for_constant (result
);
1508 PRE_EXPR_NARY (expr
) = nary
;
1509 constant
= fully_constant_expression (expr
);
1510 if (constant
!= expr
)
1513 new_val_id
= nary
->value_id
;
1514 get_or_alloc_expression_id (expr
);
1518 new_val_id
= get_next_value_id ();
1519 VEC_safe_grow_cleared (bitmap_set_t
, heap
,
1521 get_max_value_id() + 1);
1522 nary
= vn_nary_op_insert_pieces (newnary
.length
,
1529 result
, new_val_id
);
1530 PRE_EXPR_NARY (expr
) = nary
;
1531 constant
= fully_constant_expression (expr
);
1532 if (constant
!= expr
)
1534 get_or_alloc_expression_id (expr
);
1536 add_to_value (new_val_id
, expr
);
1538 phi_trans_add (oldexpr
, expr
, pred
);
1545 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1546 VEC (vn_reference_op_s
, heap
) *operands
= ref
->operands
;
1547 tree vuse
= ref
->vuse
;
1548 tree newvuse
= vuse
;
1549 VEC (vn_reference_op_s
, heap
) *newoperands
= NULL
;
1550 bool changed
= false;
1552 vn_reference_op_t operand
;
1553 vn_reference_t newref
;
1556 VEC_iterate (vn_reference_op_s
, operands
, i
, operand
); i
++, j
++)
1560 tree oldop0
= operand
->op0
;
1561 tree oldop1
= operand
->op1
;
1562 tree oldop2
= operand
->op2
;
1566 tree type
= operand
->type
;
1567 vn_reference_op_s newop
= *operand
;
1569 if (op0
&& TREE_CODE (op0
) == SSA_NAME
)
1571 unsigned int op_val_id
= VN_INFO (op0
)->value_id
;
1572 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1573 opresult
= phi_translate_1 (leader
, set1
, set2
,
1574 pred
, phiblock
, seen
);
1575 if (opresult
&& opresult
!= leader
)
1577 tree name
= get_representative_for (opresult
);
1585 changed
|= op0
!= oldop0
;
1587 if (op1
&& TREE_CODE (op1
) == SSA_NAME
)
1589 unsigned int op_val_id
= VN_INFO (op1
)->value_id
;
1590 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1591 opresult
= phi_translate_1 (leader
, set1
, set2
,
1592 pred
, phiblock
, seen
);
1593 if (opresult
&& opresult
!= leader
)
1595 tree name
= get_representative_for (opresult
);
1603 /* We can't possibly insert these. */
1604 else if (op1
&& !is_gimple_min_invariant (op1
))
1606 changed
|= op1
!= oldop1
;
1607 if (op2
&& TREE_CODE (op2
) == SSA_NAME
)
1609 unsigned int op_val_id
= VN_INFO (op2
)->value_id
;
1610 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1611 opresult
= phi_translate_1 (leader
, set1
, set2
,
1612 pred
, phiblock
, seen
);
1613 if (opresult
&& opresult
!= leader
)
1615 tree name
= get_representative_for (opresult
);
1623 /* We can't possibly insert these. */
1624 else if (op2
&& !is_gimple_min_invariant (op2
))
1626 changed
|= op2
!= oldop2
;
1629 newoperands
= VEC_copy (vn_reference_op_s
, heap
, operands
);
1630 /* We may have changed from an SSA_NAME to a constant */
1631 if (newop
.opcode
== SSA_NAME
&& TREE_CODE (op0
) != SSA_NAME
)
1632 newop
.opcode
= TREE_CODE (op0
);
1637 VEC_replace (vn_reference_op_s
, newoperands
, j
, &newop
);
1638 /* If it transforms from an SSA_NAME to an address, fold with
1639 a preceding indirect reference. */
1640 if (j
> 0 && op0
&& TREE_CODE (op0
) == ADDR_EXPR
1641 && VEC_index (vn_reference_op_s
,
1642 newoperands
, j
- 1)->opcode
== INDIRECT_REF
)
1643 vn_reference_fold_indirect (&newoperands
, &j
);
1645 if (i
!= VEC_length (vn_reference_op_s
, operands
))
1648 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1654 newvuse
= translate_vuse_through_block (newoperands
,
1655 ref
->set
, ref
->type
,
1656 vuse
, phiblock
, pred
);
1657 if (newvuse
== NULL_TREE
)
1659 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1663 changed
|= newvuse
!= vuse
;
1667 unsigned int new_val_id
;
1670 tree result
= vn_reference_lookup_pieces (newvuse
, ref
->set
,
1675 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1677 if (result
&& is_gimple_min_invariant (result
))
1679 gcc_assert (!newoperands
);
1680 return get_or_alloc_expr_for_constant (result
);
1683 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1684 expr
->kind
= REFERENCE
;
1689 PRE_EXPR_REFERENCE (expr
) = newref
;
1690 constant
= fully_constant_expression (expr
);
1691 if (constant
!= expr
)
1694 new_val_id
= newref
->value_id
;
1695 get_or_alloc_expression_id (expr
);
1699 new_val_id
= get_next_value_id ();
1700 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
1701 get_max_value_id() + 1);
1702 newref
= vn_reference_insert_pieces (newvuse
, ref
->set
,
1705 result
, new_val_id
);
1707 PRE_EXPR_REFERENCE (expr
) = newref
;
1708 constant
= fully_constant_expression (expr
);
1709 if (constant
!= expr
)
1711 get_or_alloc_expression_id (expr
);
1713 add_to_value (new_val_id
, expr
);
1715 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1716 phi_trans_add (oldexpr
, expr
, pred
);
1726 tree name
= PRE_EXPR_NAME (expr
);
1728 def_stmt
= SSA_NAME_DEF_STMT (name
);
1729 if (gimple_code (def_stmt
) == GIMPLE_PHI
1730 && gimple_bb (def_stmt
) == phiblock
)
1735 e
= find_edge (pred
, gimple_bb (phi
));
1738 tree def
= PHI_ARG_DEF (phi
, e
->dest_idx
);
1741 if (TREE_CODE (def
) == SSA_NAME
)
1742 def
= VN_INFO (def
)->valnum
;
1744 /* Handle constant. */
1745 if (is_gimple_min_invariant (def
))
1746 return get_or_alloc_expr_for_constant (def
);
1748 if (TREE_CODE (def
) == SSA_NAME
&& ssa_undefined_value_p (def
))
1751 newexpr
= get_or_alloc_expr_for_name (def
);
1762 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1764 Return NULL if we can't find a leader for each part of the
1765 translated expression. */
1768 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1769 basic_block pred
, basic_block phiblock
)
1771 bitmap_clear (seen_during_translate
);
1772 return phi_translate_1 (expr
, set1
, set2
, pred
, phiblock
,
1773 seen_during_translate
);
1776 /* For each expression in SET, translate the values through phi nodes
1777 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1778 expressions in DEST. */
1781 phi_translate_set (bitmap_set_t dest
, bitmap_set_t set
, basic_block pred
,
1782 basic_block phiblock
)
1784 VEC (pre_expr
, heap
) *exprs
;
1788 if (!phi_nodes (phiblock
))
1790 bitmap_set_copy (dest
, set
);
1794 exprs
= sorted_array_from_bitmap_set (set
);
1795 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
1797 pre_expr translated
;
1798 translated
= phi_translate (expr
, set
, NULL
, pred
, phiblock
);
1800 /* Don't add empty translations to the cache */
1802 phi_trans_add (expr
, translated
, pred
);
1804 if (translated
!= NULL
)
1805 bitmap_value_insert_into_set (dest
, translated
);
1807 VEC_free (pre_expr
, heap
, exprs
);
1810 /* Find the leader for a value (i.e., the name representing that
1811 value) in a given set, and return it. If STMT is non-NULL it
1812 makes sure the defining statement for the leader dominates it.
1813 Return NULL if no leader is found. */
1816 bitmap_find_leader (bitmap_set_t set
, unsigned int val
, gimple stmt
)
1818 if (value_id_constant_p (val
))
1822 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1824 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
1826 pre_expr expr
= expression_for_id (i
);
1827 if (expr
->kind
== CONSTANT
)
1831 if (bitmap_set_contains_value (set
, val
))
1833 /* Rather than walk the entire bitmap of expressions, and see
1834 whether any of them has the value we are looking for, we look
1835 at the reverse mapping, which tells us the set of expressions
1836 that have a given value (IE value->expressions with that
1837 value) and see if any of those expressions are in our set.
1838 The number of expressions per value is usually significantly
1839 less than the number of expressions in the set. In fact, for
1840 large testcases, doing it this way is roughly 5-10x faster
1841 than walking the bitmap.
1842 If this is somehow a significant lose for some cases, we can
1843 choose which set to walk based on which set is smaller. */
1846 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1848 EXECUTE_IF_AND_IN_BITMAP (exprset
->expressions
,
1849 set
->expressions
, 0, i
, bi
)
1851 pre_expr val
= expression_for_id (i
);
1852 /* At the point where stmt is not null, there should always
1853 be an SSA_NAME first in the list of expressions. */
1856 gimple def_stmt
= SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val
));
1857 if (gimple_code (def_stmt
) != GIMPLE_PHI
1858 && gimple_bb (def_stmt
) == gimple_bb (stmt
)
1859 && gimple_uid (def_stmt
) >= gimple_uid (stmt
))
1868 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1869 BLOCK by seeing if it is not killed in the block. Note that we are
1870 only determining whether there is a store that kills it. Because
1871 of the order in which clean iterates over values, we are guaranteed
1872 that altered operands will have caused us to be eliminated from the
1873 ANTIC_IN set already. */
1876 value_dies_in_block_x (pre_expr expr
, basic_block block
)
1878 tree vuse
= PRE_EXPR_REFERENCE (expr
)->vuse
;
1879 vn_reference_t refx
= PRE_EXPR_REFERENCE (expr
);
1881 gimple_stmt_iterator gsi
;
1882 unsigned id
= get_expression_id (expr
);
1889 /* Lookup a previously calculated result. */
1890 if (EXPR_DIES (block
)
1891 && bitmap_bit_p (EXPR_DIES (block
), id
* 2))
1892 return bitmap_bit_p (EXPR_DIES (block
), id
* 2 + 1);
1894 /* A memory expression {e, VUSE} dies in the block if there is a
1895 statement that may clobber e. If, starting statement walk from the
1896 top of the basic block, a statement uses VUSE there can be no kill
1897 inbetween that use and the original statement that loaded {e, VUSE},
1898 so we can stop walking. */
1899 ref
.base
= NULL_TREE
;
1900 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1902 tree def_vuse
, def_vdef
;
1903 def
= gsi_stmt (gsi
);
1904 def_vuse
= gimple_vuse (def
);
1905 def_vdef
= gimple_vdef (def
);
1907 /* Not a memory statement. */
1911 /* Not a may-def. */
1914 /* A load with the same VUSE, we're done. */
1915 if (def_vuse
== vuse
)
1921 /* Init ref only if we really need it. */
1922 if (ref
.base
== NULL_TREE
1923 && !ao_ref_init_from_vn_reference (&ref
, refx
->set
, refx
->type
,
1929 /* If the statement may clobber expr, it dies. */
1930 if (stmt_may_clobber_ref_p_1 (def
, &ref
))
1937 /* Remember the result. */
1938 if (!EXPR_DIES (block
))
1939 EXPR_DIES (block
) = BITMAP_ALLOC (&grand_bitmap_obstack
);
1940 bitmap_set_bit (EXPR_DIES (block
), id
* 2);
1942 bitmap_set_bit (EXPR_DIES (block
), id
* 2 + 1);
1948 #define union_contains_value(SET1, SET2, VAL) \
1949 (bitmap_set_contains_value ((SET1), (VAL)) \
1950 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1952 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
1955 vro_valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
,
1956 vn_reference_op_t vro
)
1958 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
1960 struct pre_expr_d temp
;
1963 PRE_EXPR_NAME (&temp
) = vro
->op0
;
1964 temp
.id
= lookup_expression_id (&temp
);
1967 if (!union_contains_value (set1
, set2
,
1968 get_expr_value_id (&temp
)))
1971 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
1973 struct pre_expr_d temp
;
1976 PRE_EXPR_NAME (&temp
) = vro
->op1
;
1977 temp
.id
= lookup_expression_id (&temp
);
1980 if (!union_contains_value (set1
, set2
,
1981 get_expr_value_id (&temp
)))
1985 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
1987 struct pre_expr_d temp
;
1990 PRE_EXPR_NAME (&temp
) = vro
->op2
;
1991 temp
.id
= lookup_expression_id (&temp
);
1994 if (!union_contains_value (set1
, set2
,
1995 get_expr_value_id (&temp
)))
2002 /* Determine if the expression EXPR is valid in SET1 U SET2.
2003 ONLY SET2 CAN BE NULL.
2004 This means that we have a leader for each part of the expression
2005 (if it consists of values), or the expression is an SSA_NAME.
2006 For loads/calls, we also see if the vuse is killed in this block. */
2009 valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, pre_expr expr
,
2015 return bitmap_set_contains_expr (AVAIL_OUT (block
), expr
);
2019 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2020 for (i
= 0; i
< nary
->length
; i
++)
2022 if (TREE_CODE (nary
->op
[i
]) == SSA_NAME
)
2024 struct pre_expr_d temp
;
2027 PRE_EXPR_NAME (&temp
) = nary
->op
[i
];
2028 temp
.id
= lookup_expression_id (&temp
);
2031 if (!union_contains_value (set1
, set2
,
2032 get_expr_value_id (&temp
)))
2041 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2042 vn_reference_op_t vro
;
2045 for (i
= 0; VEC_iterate (vn_reference_op_s
, ref
->operands
, i
, vro
); i
++)
2047 if (!vro_valid_in_sets (set1
, set2
, vro
))
2052 gimple def_stmt
= SSA_NAME_DEF_STMT (ref
->vuse
);
2053 if (!gimple_nop_p (def_stmt
)
2054 && gimple_bb (def_stmt
) != block
2055 && !dominated_by_p (CDI_DOMINATORS
,
2056 block
, gimple_bb (def_stmt
)))
2059 return !value_dies_in_block_x (expr
, block
);
2066 /* Clean the set of expressions that are no longer valid in SET1 or
2067 SET2. This means expressions that are made up of values we have no
2068 leaders for in SET1 or SET2. This version is used for partial
2069 anticipation, which means it is not valid in either ANTIC_IN or
2073 dependent_clean (bitmap_set_t set1
, bitmap_set_t set2
, basic_block block
)
2075 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (set1
);
2079 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
2081 if (!valid_in_sets (set1
, set2
, expr
, block
))
2082 bitmap_remove_from_set (set1
, expr
);
2084 VEC_free (pre_expr
, heap
, exprs
);
2087 /* Clean the set of expressions that are no longer valid in SET. This
2088 means expressions that are made up of values we have no leaders for
2092 clean (bitmap_set_t set
, basic_block block
)
2094 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (set
);
2098 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
2100 if (!valid_in_sets (set
, NULL
, expr
, block
))
2101 bitmap_remove_from_set (set
, expr
);
2103 VEC_free (pre_expr
, heap
, exprs
);
2106 static sbitmap has_abnormal_preds
;
2108 /* List of blocks that may have changed during ANTIC computation and
2109 thus need to be iterated over. */
2111 static sbitmap changed_blocks
;
2113 /* Decide whether to defer a block for a later iteration, or PHI
2114 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2115 should defer the block, and true if we processed it. */
2118 defer_or_phi_translate_block (bitmap_set_t dest
, bitmap_set_t source
,
2119 basic_block block
, basic_block phiblock
)
2121 if (!BB_VISITED (phiblock
))
2123 SET_BIT (changed_blocks
, block
->index
);
2124 BB_VISITED (block
) = 0;
2125 BB_DEFERRED (block
) = 1;
2129 phi_translate_set (dest
, source
, block
, phiblock
);
2133 /* Compute the ANTIC set for BLOCK.
2135 If succs(BLOCK) > 1 then
2136 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2137 else if succs(BLOCK) == 1 then
2138 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2140 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2144 compute_antic_aux (basic_block block
, bool block_has_abnormal_pred_edge
)
2146 bool changed
= false;
2147 bitmap_set_t S
, old
, ANTIC_OUT
;
2153 old
= ANTIC_OUT
= S
= NULL
;
2154 BB_VISITED (block
) = 1;
2156 /* If any edges from predecessors are abnormal, antic_in is empty,
2158 if (block_has_abnormal_pred_edge
)
2159 goto maybe_dump_sets
;
2161 old
= ANTIC_IN (block
);
2162 ANTIC_OUT
= bitmap_set_new ();
2164 /* If the block has no successors, ANTIC_OUT is empty. */
2165 if (EDGE_COUNT (block
->succs
) == 0)
2167 /* If we have one successor, we could have some phi nodes to
2168 translate through. */
2169 else if (single_succ_p (block
))
2171 basic_block succ_bb
= single_succ (block
);
2173 /* We trade iterations of the dataflow equations for having to
2174 phi translate the maximal set, which is incredibly slow
2175 (since the maximal set often has 300+ members, even when you
2176 have a small number of blocks).
2177 Basically, we defer the computation of ANTIC for this block
2178 until we have processed it's successor, which will inevitably
2179 have a *much* smaller set of values to phi translate once
2180 clean has been run on it.
2181 The cost of doing this is that we technically perform more
2182 iterations, however, they are lower cost iterations.
2184 Timings for PRE on tramp3d-v4:
2185 without maximal set fix: 11 seconds
2186 with maximal set fix/without deferring: 26 seconds
2187 with maximal set fix/with deferring: 11 seconds
2190 if (!defer_or_phi_translate_block (ANTIC_OUT
, ANTIC_IN (succ_bb
),
2194 goto maybe_dump_sets
;
2197 /* If we have multiple successors, we take the intersection of all of
2198 them. Note that in the case of loop exit phi nodes, we may have
2199 phis to translate through. */
2202 VEC(basic_block
, heap
) * worklist
;
2204 basic_block bprime
, first
;
2206 worklist
= VEC_alloc (basic_block
, heap
, EDGE_COUNT (block
->succs
));
2207 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2208 VEC_quick_push (basic_block
, worklist
, e
->dest
);
2209 first
= VEC_index (basic_block
, worklist
, 0);
2211 if (phi_nodes (first
))
2213 bitmap_set_t from
= ANTIC_IN (first
);
2215 if (!BB_VISITED (first
))
2217 phi_translate_set (ANTIC_OUT
, from
, block
, first
);
2221 if (!BB_VISITED (first
))
2222 bitmap_set_copy (ANTIC_OUT
, maximal_set
);
2224 bitmap_set_copy (ANTIC_OUT
, ANTIC_IN (first
));
2227 for (i
= 1; VEC_iterate (basic_block
, worklist
, i
, bprime
); i
++)
2229 if (phi_nodes (bprime
))
2231 bitmap_set_t tmp
= bitmap_set_new ();
2232 bitmap_set_t from
= ANTIC_IN (bprime
);
2234 if (!BB_VISITED (bprime
))
2236 phi_translate_set (tmp
, from
, block
, bprime
);
2237 bitmap_set_and (ANTIC_OUT
, tmp
);
2238 bitmap_set_free (tmp
);
2242 if (!BB_VISITED (bprime
))
2243 bitmap_set_and (ANTIC_OUT
, maximal_set
);
2245 bitmap_set_and (ANTIC_OUT
, ANTIC_IN (bprime
));
2248 VEC_free (basic_block
, heap
, worklist
);
2251 /* Generate ANTIC_OUT - TMP_GEN. */
2252 S
= bitmap_set_subtract (ANTIC_OUT
, TMP_GEN (block
));
2254 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2255 ANTIC_IN (block
) = bitmap_set_subtract (EXP_GEN (block
),
2258 /* Then union in the ANTIC_OUT - TMP_GEN values,
2259 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2260 FOR_EACH_EXPR_ID_IN_SET (S
, bii
, bi
)
2261 bitmap_value_insert_into_set (ANTIC_IN (block
),
2262 expression_for_id (bii
));
2264 clean (ANTIC_IN (block
), block
);
2266 /* !old->expressions can happen when we deferred a block. */
2267 if (!old
->expressions
|| !bitmap_set_equal (old
, ANTIC_IN (block
)))
2270 SET_BIT (changed_blocks
, block
->index
);
2271 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2272 SET_BIT (changed_blocks
, e
->src
->index
);
2275 RESET_BIT (changed_blocks
, block
->index
);
2278 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2280 if (!BB_DEFERRED (block
) || BB_VISITED (block
))
2283 print_bitmap_set (dump_file
, ANTIC_OUT
, "ANTIC_OUT", block
->index
);
2285 print_bitmap_set (dump_file
, ANTIC_IN (block
), "ANTIC_IN",
2289 print_bitmap_set (dump_file
, S
, "S", block
->index
);
2294 "Block %d was deferred for a future iteration.\n",
2299 bitmap_set_free (old
);
2301 bitmap_set_free (S
);
2303 bitmap_set_free (ANTIC_OUT
);
2307 /* Compute PARTIAL_ANTIC for BLOCK.
2309 If succs(BLOCK) > 1 then
2310 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2311 in ANTIC_OUT for all succ(BLOCK)
2312 else if succs(BLOCK) == 1 then
2313 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2315 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2320 compute_partial_antic_aux (basic_block block
,
2321 bool block_has_abnormal_pred_edge
)
2323 bool changed
= false;
2324 bitmap_set_t old_PA_IN
;
2325 bitmap_set_t PA_OUT
;
2328 unsigned long max_pa
= PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH
);
2330 old_PA_IN
= PA_OUT
= NULL
;
2332 /* If any edges from predecessors are abnormal, antic_in is empty,
2334 if (block_has_abnormal_pred_edge
)
2335 goto maybe_dump_sets
;
2337 /* If there are too many partially anticipatable values in the
2338 block, phi_translate_set can take an exponential time: stop
2339 before the translation starts. */
2341 && single_succ_p (block
)
2342 && bitmap_count_bits (PA_IN (single_succ (block
))->values
) > max_pa
)
2343 goto maybe_dump_sets
;
2345 old_PA_IN
= PA_IN (block
);
2346 PA_OUT
= bitmap_set_new ();
2348 /* If the block has no successors, ANTIC_OUT is empty. */
2349 if (EDGE_COUNT (block
->succs
) == 0)
2351 /* If we have one successor, we could have some phi nodes to
2352 translate through. Note that we can't phi translate across DFS
2353 back edges in partial antic, because it uses a union operation on
2354 the successors. For recurrences like IV's, we will end up
2355 generating a new value in the set on each go around (i + 3 (VH.1)
2356 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2357 else if (single_succ_p (block
))
2359 basic_block succ
= single_succ (block
);
2360 if (!(single_succ_edge (block
)->flags
& EDGE_DFS_BACK
))
2361 phi_translate_set (PA_OUT
, PA_IN (succ
), block
, succ
);
2363 /* If we have multiple successors, we take the union of all of
2367 VEC(basic_block
, heap
) * worklist
;
2371 worklist
= VEC_alloc (basic_block
, heap
, EDGE_COUNT (block
->succs
));
2372 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2374 if (e
->flags
& EDGE_DFS_BACK
)
2376 VEC_quick_push (basic_block
, worklist
, e
->dest
);
2378 if (VEC_length (basic_block
, worklist
) > 0)
2380 for (i
= 0; VEC_iterate (basic_block
, worklist
, i
, bprime
); i
++)
2385 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime
), i
, bi
)
2386 bitmap_value_insert_into_set (PA_OUT
,
2387 expression_for_id (i
));
2388 if (phi_nodes (bprime
))
2390 bitmap_set_t pa_in
= bitmap_set_new ();
2391 phi_translate_set (pa_in
, PA_IN (bprime
), block
, bprime
);
2392 FOR_EACH_EXPR_ID_IN_SET (pa_in
, i
, bi
)
2393 bitmap_value_insert_into_set (PA_OUT
,
2394 expression_for_id (i
));
2395 bitmap_set_free (pa_in
);
2398 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime
), i
, bi
)
2399 bitmap_value_insert_into_set (PA_OUT
,
2400 expression_for_id (i
));
2403 VEC_free (basic_block
, heap
, worklist
);
2406 /* PA_IN starts with PA_OUT - TMP_GEN.
2407 Then we subtract things from ANTIC_IN. */
2408 PA_IN (block
) = bitmap_set_subtract (PA_OUT
, TMP_GEN (block
));
2410 /* For partial antic, we want to put back in the phi results, since
2411 we will properly avoid making them partially antic over backedges. */
2412 bitmap_ior_into (PA_IN (block
)->values
, PHI_GEN (block
)->values
);
2413 bitmap_ior_into (PA_IN (block
)->expressions
, PHI_GEN (block
)->expressions
);
2415 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2416 bitmap_set_subtract_values (PA_IN (block
), ANTIC_IN (block
));
2418 dependent_clean (PA_IN (block
), ANTIC_IN (block
), block
);
2420 if (!bitmap_set_equal (old_PA_IN
, PA_IN (block
)))
2423 SET_BIT (changed_blocks
, block
->index
);
2424 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2425 SET_BIT (changed_blocks
, e
->src
->index
);
2428 RESET_BIT (changed_blocks
, block
->index
);
2431 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2434 print_bitmap_set (dump_file
, PA_OUT
, "PA_OUT", block
->index
);
2436 print_bitmap_set (dump_file
, PA_IN (block
), "PA_IN", block
->index
);
2439 bitmap_set_free (old_PA_IN
);
2441 bitmap_set_free (PA_OUT
);
2445 /* Compute ANTIC and partial ANTIC sets. */
2448 compute_antic (void)
2450 bool changed
= true;
2451 int num_iterations
= 0;
2455 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2456 We pre-build the map of blocks with incoming abnormal edges here. */
2457 has_abnormal_preds
= sbitmap_alloc (last_basic_block
);
2458 sbitmap_zero (has_abnormal_preds
);
2465 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2467 e
->flags
&= ~EDGE_DFS_BACK
;
2468 if (e
->flags
& EDGE_ABNORMAL
)
2470 SET_BIT (has_abnormal_preds
, block
->index
);
2475 BB_VISITED (block
) = 0;
2476 BB_DEFERRED (block
) = 0;
2477 /* While we are here, give empty ANTIC_IN sets to each block. */
2478 ANTIC_IN (block
) = bitmap_set_new ();
2479 PA_IN (block
) = bitmap_set_new ();
2482 /* At the exit block we anticipate nothing. */
2483 ANTIC_IN (EXIT_BLOCK_PTR
) = bitmap_set_new ();
2484 BB_VISITED (EXIT_BLOCK_PTR
) = 1;
2485 PA_IN (EXIT_BLOCK_PTR
) = bitmap_set_new ();
2487 changed_blocks
= sbitmap_alloc (last_basic_block
+ 1);
2488 sbitmap_ones (changed_blocks
);
2491 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2492 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2495 for (i
= 0; i
< n_basic_blocks
- NUM_FIXED_BLOCKS
; i
++)
2497 if (TEST_BIT (changed_blocks
, postorder
[i
]))
2499 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2500 changed
|= compute_antic_aux (block
,
2501 TEST_BIT (has_abnormal_preds
,
2505 #ifdef ENABLE_CHECKING
2506 /* Theoretically possible, but *highly* unlikely. */
2507 gcc_assert (num_iterations
< 500);
2511 statistics_histogram_event (cfun
, "compute_antic iterations",
2514 if (do_partial_partial
)
2516 sbitmap_ones (changed_blocks
);
2517 mark_dfs_back_edges ();
2522 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2523 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2526 for (i
= 0; i
< n_basic_blocks
- NUM_FIXED_BLOCKS
; i
++)
2528 if (TEST_BIT (changed_blocks
, postorder
[i
]))
2530 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2532 |= compute_partial_antic_aux (block
,
2533 TEST_BIT (has_abnormal_preds
,
2537 #ifdef ENABLE_CHECKING
2538 /* Theoretically possible, but *highly* unlikely. */
2539 gcc_assert (num_iterations
< 500);
2542 statistics_histogram_event (cfun
, "compute_partial_antic iterations",
2545 sbitmap_free (has_abnormal_preds
);
2546 sbitmap_free (changed_blocks
);
2549 /* Return true if we can value number the call in STMT. This is true
2550 if we have a pure or constant call. */
2553 can_value_number_call (gimple stmt
)
2555 if (gimple_call_flags (stmt
) & (ECF_PURE
| ECF_CONST
))
2560 /* Return true if OP is an exception handler related operation, such as
2561 FILTER_EXPR or EXC_PTR_EXPR. */
2564 is_exception_related (gimple stmt
)
2566 return (is_gimple_assign (stmt
)
2567 && (gimple_assign_rhs_code (stmt
) == FILTER_EXPR
2568 || gimple_assign_rhs_code (stmt
) == EXC_PTR_EXPR
));
2571 /* Return true if OP is a tree which we can perform PRE on.
2572 This may not match the operations we can value number, but in
2573 a perfect world would. */
2576 can_PRE_operation (tree op
)
2578 return UNARY_CLASS_P (op
)
2579 || BINARY_CLASS_P (op
)
2580 || COMPARISON_CLASS_P (op
)
2581 || TREE_CODE (op
) == INDIRECT_REF
2582 || TREE_CODE (op
) == COMPONENT_REF
2583 || TREE_CODE (op
) == VIEW_CONVERT_EXPR
2584 || TREE_CODE (op
) == CALL_EXPR
2585 || TREE_CODE (op
) == ARRAY_REF
;
2589 /* Inserted expressions are placed onto this worklist, which is used
2590 for performing quick dead code elimination of insertions we made
2591 that didn't turn out to be necessary. */
2592 static VEC(gimple
,heap
) *inserted_exprs
;
2593 static bitmap inserted_phi_names
;
2595 /* Pool allocated fake store expressions are placed onto this
2596 worklist, which, after performing dead code elimination, is walked
2597 to see which expressions need to be put into GC'able memory */
2598 static VEC(gimple
, heap
) *need_creation
;
2600 /* The actual worker for create_component_ref_by_pieces. */
2603 create_component_ref_by_pieces_1 (basic_block block
, vn_reference_t ref
,
2604 unsigned int *operand
, gimple_seq
*stmts
,
2607 vn_reference_op_t currop
= VEC_index (vn_reference_op_s
, ref
->operands
,
2611 switch (currop
->opcode
)
2615 tree folded
, sc
= currop
->op1
;
2616 unsigned int nargs
= 0;
2617 tree
*args
= XNEWVEC (tree
, VEC_length (vn_reference_op_s
,
2618 ref
->operands
) - 1);
2619 while (*operand
< VEC_length (vn_reference_op_s
, ref
->operands
))
2621 args
[nargs
] = create_component_ref_by_pieces_1 (block
, ref
,
2626 folded
= build_call_array (currop
->type
,
2627 TREE_CODE (currop
->op0
) == FUNCTION_DECL
2628 ? build_fold_addr_expr (currop
->op0
)
2634 pre_expr scexpr
= get_or_alloc_expr_for (sc
);
2635 sc
= find_or_generate_expression (block
, scexpr
, stmts
, domstmt
);
2638 CALL_EXPR_STATIC_CHAIN (folded
) = sc
;
2643 case TARGET_MEM_REF
:
2645 vn_reference_op_t nextop
= VEC_index (vn_reference_op_s
, ref
->operands
,
2648 tree genop0
= NULL_TREE
;
2649 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2655 op0expr
= get_or_alloc_expr_for (currop
->op0
);
2656 genop0
= find_or_generate_expression (block
, op0expr
,
2661 if (DECL_P (baseop
))
2662 return build6 (TARGET_MEM_REF
, currop
->type
,
2664 genop0
, currop
->op1
, currop
->op2
,
2665 unshare_expr (nextop
->op1
));
2667 return build6 (TARGET_MEM_REF
, currop
->type
,
2669 genop0
, currop
->op1
, currop
->op2
,
2670 unshare_expr (nextop
->op1
));
2676 gcc_assert (is_gimple_min_invariant (currop
->op0
));
2682 case VIEW_CONVERT_EXPR
:
2685 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
,
2690 folded
= fold_build1 (currop
->opcode
, currop
->type
,
2695 case ALIGN_INDIRECT_REF
:
2696 case MISALIGNED_INDIRECT_REF
:
2700 tree genop1
= create_component_ref_by_pieces_1 (block
, ref
,
2705 genop1
= fold_convert (build_pointer_type (currop
->type
),
2708 if (currop
->opcode
== MISALIGNED_INDIRECT_REF
)
2709 folded
= fold_build2 (currop
->opcode
, currop
->type
,
2710 genop1
, currop
->op1
);
2712 folded
= fold_build1 (currop
->opcode
, currop
->type
,
2720 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2722 pre_expr op1expr
= get_or_alloc_expr_for (currop
->op0
);
2723 pre_expr op2expr
= get_or_alloc_expr_for (currop
->op1
);
2729 genop1
= find_or_generate_expression (block
, op1expr
, stmts
, domstmt
);
2732 genop2
= find_or_generate_expression (block
, op2expr
, stmts
, domstmt
);
2735 folded
= fold_build3 (BIT_FIELD_REF
, currop
->type
, genop0
, genop1
,
2740 /* For array ref vn_reference_op's, operand 1 of the array ref
2741 is op0 of the reference op and operand 3 of the array ref is
2743 case ARRAY_RANGE_REF
:
2747 tree genop1
= currop
->op0
;
2749 tree genop2
= currop
->op1
;
2751 tree genop3
= currop
->op2
;
2753 genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2757 op1expr
= get_or_alloc_expr_for (genop1
);
2758 genop1
= find_or_generate_expression (block
, op1expr
, stmts
, domstmt
);
2763 op2expr
= get_or_alloc_expr_for (genop2
);
2764 genop2
= find_or_generate_expression (block
, op2expr
, stmts
,
2771 tree elmt_type
= TREE_TYPE (TREE_TYPE (genop0
));
2772 genop3
= size_binop (EXACT_DIV_EXPR
, genop3
,
2773 size_int (TYPE_ALIGN_UNIT (elmt_type
)));
2774 op3expr
= get_or_alloc_expr_for (genop3
);
2775 genop3
= find_or_generate_expression (block
, op3expr
, stmts
,
2780 return build4 (currop
->opcode
, currop
->type
, genop0
, genop1
,
2787 tree genop2
= currop
->op1
;
2789 op0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2793 /* op1 should be a FIELD_DECL, which are represented by
2798 op2expr
= get_or_alloc_expr_for (genop2
);
2799 genop2
= find_or_generate_expression (block
, op2expr
, stmts
,
2805 return fold_build3 (COMPONENT_REF
, TREE_TYPE (op1
), op0
, op1
,
2811 pre_expr op0expr
= get_or_alloc_expr_for (currop
->op0
);
2812 genop
= find_or_generate_expression (block
, op0expr
, stmts
, domstmt
);
2833 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2834 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2835 trying to rename aggregates into ssa form directly, which is a no no.
2837 Thus, this routine doesn't create temporaries, it just builds a
2838 single access expression for the array, calling
2839 find_or_generate_expression to build the innermost pieces.
2841 This function is a subroutine of create_expression_by_pieces, and
2842 should not be called on it's own unless you really know what you
2846 create_component_ref_by_pieces (basic_block block
, vn_reference_t ref
,
2847 gimple_seq
*stmts
, gimple domstmt
)
2849 unsigned int op
= 0;
2850 return create_component_ref_by_pieces_1 (block
, ref
, &op
, stmts
, domstmt
);
2853 /* Find a leader for an expression, or generate one using
2854 create_expression_by_pieces if it's ANTIC but
2856 BLOCK is the basic_block we are looking for leaders in.
2857 EXPR is the expression to find a leader or generate for.
2858 STMTS is the statement list to put the inserted expressions on.
2859 Returns the SSA_NAME of the LHS of the generated expression or the
2861 DOMSTMT if non-NULL is a statement that should be dominated by
2862 all uses in the generated expression. If DOMSTMT is non-NULL this
2863 routine can fail and return NULL_TREE. Otherwise it will assert
2867 find_or_generate_expression (basic_block block
, pre_expr expr
,
2868 gimple_seq
*stmts
, gimple domstmt
)
2870 pre_expr leader
= bitmap_find_leader (AVAIL_OUT (block
),
2871 get_expr_value_id (expr
), domstmt
);
2875 if (leader
->kind
== NAME
)
2876 genop
= PRE_EXPR_NAME (leader
);
2877 else if (leader
->kind
== CONSTANT
)
2878 genop
= PRE_EXPR_CONSTANT (leader
);
2881 /* If it's still NULL, it must be a complex expression, so generate
2882 it recursively. Not so for FRE though. */
2886 bitmap_set_t exprset
;
2887 unsigned int lookfor
= get_expr_value_id (expr
);
2888 bool handled
= false;
2892 exprset
= VEC_index (bitmap_set_t
, value_expressions
, lookfor
);
2893 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
2895 pre_expr temp
= expression_for_id (i
);
2896 if (temp
->kind
!= NAME
)
2899 genop
= create_expression_by_pieces (block
, temp
, stmts
,
2901 get_expr_type (expr
));
2905 if (!handled
&& domstmt
)
2908 gcc_assert (handled
);
2913 #define NECESSARY GF_PLF_1
2915 /* Create an expression in pieces, so that we can handle very complex
2916 expressions that may be ANTIC, but not necessary GIMPLE.
2917 BLOCK is the basic block the expression will be inserted into,
2918 EXPR is the expression to insert (in value form)
2919 STMTS is a statement list to append the necessary insertions into.
2921 This function will die if we hit some value that shouldn't be
2922 ANTIC but is (IE there is no leader for it, or its components).
2923 This function may also generate expressions that are themselves
2924 partially or fully redundant. Those that are will be either made
2925 fully redundant during the next iteration of insert (for partially
2926 redundant ones), or eliminated by eliminate (for fully redundant
2929 If DOMSTMT is non-NULL then we make sure that all uses in the
2930 expressions dominate that statement. In this case the function
2931 can return NULL_TREE to signal failure. */
2934 create_expression_by_pieces (basic_block block
, pre_expr expr
,
2935 gimple_seq
*stmts
, gimple domstmt
, tree type
)
2939 gimple_seq forced_stmts
= NULL
;
2940 unsigned int value_id
;
2941 gimple_stmt_iterator gsi
;
2942 tree exprtype
= type
? type
: get_expr_type (expr
);
2948 /* We may hit the NAME/CONSTANT case if we have to convert types
2949 that value numbering saw through. */
2951 folded
= PRE_EXPR_NAME (expr
);
2954 folded
= PRE_EXPR_CONSTANT (expr
);
2958 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2959 folded
= create_component_ref_by_pieces (block
, ref
, stmts
, domstmt
);
2964 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2965 switch (nary
->length
)
2969 pre_expr op1
= get_or_alloc_expr_for (nary
->op
[0]);
2970 pre_expr op2
= get_or_alloc_expr_for (nary
->op
[1]);
2971 tree genop1
= find_or_generate_expression (block
, op1
,
2973 tree genop2
= find_or_generate_expression (block
, op2
,
2975 if (!genop1
|| !genop2
)
2977 genop1
= fold_convert (TREE_TYPE (nary
->op
[0]),
2979 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
2980 may be a constant with the wrong type. */
2981 if (nary
->opcode
== POINTER_PLUS_EXPR
)
2982 genop2
= fold_convert (sizetype
, genop2
);
2984 genop2
= fold_convert (TREE_TYPE (nary
->op
[1]), genop2
);
2986 folded
= fold_build2 (nary
->opcode
, nary
->type
,
2992 pre_expr op1
= get_or_alloc_expr_for (nary
->op
[0]);
2993 tree genop1
= find_or_generate_expression (block
, op1
,
2997 genop1
= fold_convert (TREE_TYPE (nary
->op
[0]), genop1
);
2999 folded
= fold_build1 (nary
->opcode
, nary
->type
,
3012 if (!useless_type_conversion_p (exprtype
, TREE_TYPE (folded
)))
3013 folded
= fold_convert (exprtype
, folded
);
3015 /* Force the generated expression to be a sequence of GIMPLE
3017 We have to call unshare_expr because force_gimple_operand may
3018 modify the tree we pass to it. */
3019 folded
= force_gimple_operand (unshare_expr (folded
), &forced_stmts
,
3022 /* If we have any intermediate expressions to the value sets, add them
3023 to the value sets and chain them in the instruction stream. */
3026 gsi
= gsi_start (forced_stmts
);
3027 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3029 gimple stmt
= gsi_stmt (gsi
);
3030 tree forcedname
= gimple_get_lhs (stmt
);
3033 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3034 if (TREE_CODE (forcedname
) == SSA_NAME
)
3036 VN_INFO_GET (forcedname
)->valnum
= forcedname
;
3037 VN_INFO (forcedname
)->value_id
= get_next_value_id ();
3038 nameexpr
= get_or_alloc_expr_for_name (forcedname
);
3039 add_to_value (VN_INFO (forcedname
)->value_id
, nameexpr
);
3041 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3042 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3044 mark_symbols_for_renaming (stmt
);
3046 gimple_seq_add_seq (stmts
, forced_stmts
);
3049 /* Build and insert the assignment of the end result to the temporary
3050 that we will return. */
3051 if (!pretemp
|| exprtype
!= TREE_TYPE (pretemp
))
3053 pretemp
= create_tmp_var (exprtype
, "pretmp");
3054 get_var_ann (pretemp
);
3058 add_referenced_var (temp
);
3060 if (TREE_CODE (exprtype
) == COMPLEX_TYPE
3061 || TREE_CODE (exprtype
) == VECTOR_TYPE
)
3062 DECL_GIMPLE_REG_P (temp
) = 1;
3064 newstmt
= gimple_build_assign (temp
, folded
);
3065 name
= make_ssa_name (temp
, newstmt
);
3066 gimple_assign_set_lhs (newstmt
, name
);
3067 gimple_set_plf (newstmt
, NECESSARY
, false);
3069 gimple_seq_add_stmt (stmts
, newstmt
);
3070 VEC_safe_push (gimple
, heap
, inserted_exprs
, newstmt
);
3072 /* All the symbols in NEWEXPR should be put into SSA form. */
3073 mark_symbols_for_renaming (newstmt
);
3075 /* Add a value number to the temporary.
3076 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3077 we are creating the expression by pieces, and this particular piece of
3078 the expression may have been represented. There is no harm in replacing
3080 VN_INFO_GET (name
)->valnum
= name
;
3081 value_id
= get_expr_value_id (expr
);
3082 VN_INFO (name
)->value_id
= value_id
;
3083 nameexpr
= get_or_alloc_expr_for_name (name
);
3084 add_to_value (value_id
, nameexpr
);
3086 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3087 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3089 pre_stats
.insertions
++;
3090 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3092 fprintf (dump_file
, "Inserted ");
3093 print_gimple_stmt (dump_file
, newstmt
, 0, 0);
3094 fprintf (dump_file
, " in predecessor %d\n", block
->index
);
3101 /* Returns true if we want to inhibit the insertions of PHI nodes
3102 for the given EXPR for basic block BB (a member of a loop).
3103 We want to do this, when we fear that the induction variable we
3104 create might inhibit vectorization. */
3107 inhibit_phi_insertion (basic_block bb
, pre_expr expr
)
3109 vn_reference_t vr
= PRE_EXPR_REFERENCE (expr
);
3110 VEC (vn_reference_op_s
, heap
) *ops
= vr
->operands
;
3111 vn_reference_op_t op
;
3114 /* If we aren't going to vectorize we don't inhibit anything. */
3115 if (!flag_tree_vectorize
)
3118 /* Otherwise we inhibit the insertion when the address of the
3119 memory reference is a simple induction variable. In other
3120 cases the vectorizer won't do anything anyway (either it's
3121 loop invariant or a complicated expression). */
3122 for (i
= 0; VEC_iterate (vn_reference_op_s
, ops
, i
, op
); ++i
)
3127 case ARRAY_RANGE_REF
:
3128 if (TREE_CODE (op
->op0
) != SSA_NAME
)
3133 basic_block defbb
= gimple_bb (SSA_NAME_DEF_STMT (op
->op0
));
3135 /* Default defs are loop invariant. */
3138 /* Defined outside this loop, also loop invariant. */
3139 if (!flow_bb_inside_loop_p (bb
->loop_father
, defbb
))
3141 /* If it's a simple induction variable inhibit insertion,
3142 the vectorizer might be interested in this one. */
3143 if (simple_iv (bb
->loop_father
, bb
->loop_father
,
3144 op
->op0
, &iv
, true))
3146 /* No simple IV, vectorizer can't do anything, hence no
3147 reason to inhibit the transformation for this operand. */
3157 /* Insert the to-be-made-available values of expression EXPRNUM for each
3158 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3159 merge the result with a phi node, given the same value number as
3160 NODE. Return true if we have inserted new stuff. */
3163 insert_into_preds_of_block (basic_block block
, unsigned int exprnum
,
3166 pre_expr expr
= expression_for_id (exprnum
);
3168 unsigned int val
= get_expr_value_id (expr
);
3170 bool insertions
= false;
3175 tree type
= get_expr_type (expr
);
3179 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3181 fprintf (dump_file
, "Found partial redundancy for expression ");
3182 print_pre_expr (dump_file
, expr
);
3183 fprintf (dump_file
, " (%04d)\n", val
);
3186 /* Make sure we aren't creating an induction variable. */
3187 if (block
->loop_depth
> 0 && EDGE_COUNT (block
->preds
) == 2)
3189 bool firstinsideloop
= false;
3190 bool secondinsideloop
= false;
3191 firstinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3192 EDGE_PRED (block
, 0)->src
);
3193 secondinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3194 EDGE_PRED (block
, 1)->src
);
3195 /* Induction variables only have one edge inside the loop. */
3196 if ((firstinsideloop
^ secondinsideloop
)
3197 && (expr
->kind
!= REFERENCE
3198 || inhibit_phi_insertion (block
, expr
)))
3200 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3201 fprintf (dump_file
, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3206 /* Make sure we are not inserting trapping expressions. */
3207 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3210 eprime
= avail
[bprime
->index
];
3211 if (eprime
->kind
== NARY
3212 && vn_nary_may_trap (PRE_EXPR_NARY (eprime
)))
3216 /* Make the necessary insertions. */
3217 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3219 gimple_seq stmts
= NULL
;
3222 eprime
= avail
[bprime
->index
];
3224 if (eprime
->kind
!= NAME
&& eprime
->kind
!= CONSTANT
)
3226 builtexpr
= create_expression_by_pieces (bprime
,
3230 gcc_assert (!(pred
->flags
& EDGE_ABNORMAL
));
3231 gsi_insert_seq_on_edge (pred
, stmts
);
3232 avail
[bprime
->index
] = get_or_alloc_expr_for_name (builtexpr
);
3235 else if (eprime
->kind
== CONSTANT
)
3237 /* Constants may not have the right type, fold_convert
3238 should give us back a constant with the right type.
3240 tree constant
= PRE_EXPR_CONSTANT (eprime
);
3241 if (!useless_type_conversion_p (type
, TREE_TYPE (constant
)))
3243 tree builtexpr
= fold_convert (type
, constant
);
3244 if (!is_gimple_min_invariant (builtexpr
))
3246 tree forcedexpr
= force_gimple_operand (builtexpr
,
3249 if (!is_gimple_min_invariant (forcedexpr
))
3251 if (forcedexpr
!= builtexpr
)
3253 VN_INFO_GET (forcedexpr
)->valnum
= PRE_EXPR_CONSTANT (eprime
);
3254 VN_INFO (forcedexpr
)->value_id
= get_expr_value_id (eprime
);
3258 gimple_stmt_iterator gsi
;
3259 gsi
= gsi_start (stmts
);
3260 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3262 gimple stmt
= gsi_stmt (gsi
);
3263 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3264 gimple_set_plf (stmt
, NECESSARY
, false);
3266 gsi_insert_seq_on_edge (pred
, stmts
);
3268 avail
[bprime
->index
] = get_or_alloc_expr_for_name (forcedexpr
);
3273 else if (eprime
->kind
== NAME
)
3275 /* We may have to do a conversion because our value
3276 numbering can look through types in certain cases, but
3277 our IL requires all operands of a phi node have the same
3279 tree name
= PRE_EXPR_NAME (eprime
);
3280 if (!useless_type_conversion_p (type
, TREE_TYPE (name
)))
3284 builtexpr
= fold_convert (type
, name
);
3285 forcedexpr
= force_gimple_operand (builtexpr
,
3289 if (forcedexpr
!= name
)
3291 VN_INFO_GET (forcedexpr
)->valnum
= VN_INFO (name
)->valnum
;
3292 VN_INFO (forcedexpr
)->value_id
= VN_INFO (name
)->value_id
;
3297 gimple_stmt_iterator gsi
;
3298 gsi
= gsi_start (stmts
);
3299 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3301 gimple stmt
= gsi_stmt (gsi
);
3302 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3303 gimple_set_plf (stmt
, NECESSARY
, false);
3305 gsi_insert_seq_on_edge (pred
, stmts
);
3307 avail
[bprime
->index
] = get_or_alloc_expr_for_name (forcedexpr
);
3311 /* If we didn't want a phi node, and we made insertions, we still have
3312 inserted new stuff, and thus return true. If we didn't want a phi node,
3313 and didn't make insertions, we haven't added anything new, so return
3315 if (nophi
&& insertions
)
3317 else if (nophi
&& !insertions
)
3320 /* Now build a phi for the new variable. */
3321 if (!prephitemp
|| TREE_TYPE (prephitemp
) != type
)
3323 prephitemp
= create_tmp_var (type
, "prephitmp");
3324 get_var_ann (prephitemp
);
3328 add_referenced_var (temp
);
3330 if (TREE_CODE (type
) == COMPLEX_TYPE
3331 || TREE_CODE (type
) == VECTOR_TYPE
)
3332 DECL_GIMPLE_REG_P (temp
) = 1;
3333 phi
= create_phi_node (temp
, block
);
3335 gimple_set_plf (phi
, NECESSARY
, false);
3336 VN_INFO_GET (gimple_phi_result (phi
))->valnum
= gimple_phi_result (phi
);
3337 VN_INFO (gimple_phi_result (phi
))->value_id
= val
;
3338 VEC_safe_push (gimple
, heap
, inserted_exprs
, phi
);
3339 bitmap_set_bit (inserted_phi_names
,
3340 SSA_NAME_VERSION (gimple_phi_result (phi
)));
3341 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3343 pre_expr ae
= avail
[pred
->src
->index
];
3344 gcc_assert (get_expr_type (ae
) == type
3345 || useless_type_conversion_p (type
, get_expr_type (ae
)));
3346 if (ae
->kind
== CONSTANT
)
3347 add_phi_arg (phi
, PRE_EXPR_CONSTANT (ae
), pred
, UNKNOWN_LOCATION
);
3349 add_phi_arg (phi
, PRE_EXPR_NAME (avail
[pred
->src
->index
]), pred
,
3353 newphi
= get_or_alloc_expr_for_name (gimple_phi_result (phi
));
3354 add_to_value (val
, newphi
);
3356 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3357 this insertion, since we test for the existence of this value in PHI_GEN
3358 before proceeding with the partial redundancy checks in insert_aux.
3360 The value may exist in AVAIL_OUT, in particular, it could be represented
3361 by the expression we are trying to eliminate, in which case we want the
3362 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3365 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3366 this block, because if it did, it would have existed in our dominator's
3367 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3370 bitmap_insert_into_set (PHI_GEN (block
), newphi
);
3371 bitmap_value_replace_in_set (AVAIL_OUT (block
),
3373 bitmap_insert_into_set (NEW_SETS (block
),
3376 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3378 fprintf (dump_file
, "Created phi ");
3379 print_gimple_stmt (dump_file
, phi
, 0, 0);
3380 fprintf (dump_file
, " in block %d\n", block
->index
);
3388 /* Perform insertion of partially redundant values.
3389 For BLOCK, do the following:
3390 1. Propagate the NEW_SETS of the dominator into the current block.
3391 If the block has multiple predecessors,
3392 2a. Iterate over the ANTIC expressions for the block to see if
3393 any of them are partially redundant.
3394 2b. If so, insert them into the necessary predecessors to make
3395 the expression fully redundant.
3396 2c. Insert a new PHI merging the values of the predecessors.
3397 2d. Insert the new PHI, and the new expressions, into the
3399 3. Recursively call ourselves on the dominator children of BLOCK.
3401 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3402 do_regular_insertion and do_partial_insertion.
3407 do_regular_insertion (basic_block block
, basic_block dom
)
3409 bool new_stuff
= false;
3410 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (ANTIC_IN (block
));
3414 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
3416 if (expr
->kind
!= NAME
)
3420 bool by_some
= false;
3421 bool cant_insert
= false;
3422 bool all_same
= true;
3423 pre_expr first_s
= NULL
;
3426 pre_expr eprime
= NULL
;
3428 pre_expr edoubleprime
= NULL
;
3430 val
= get_expr_value_id (expr
);
3431 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3433 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3435 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3436 fprintf (dump_file
, "Found fully redundant value\n");
3440 avail
= XCNEWVEC (pre_expr
, last_basic_block
);
3441 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3443 unsigned int vprime
;
3445 /* We should never run insertion for the exit block
3446 and so not come across fake pred edges. */
3447 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3449 eprime
= phi_translate (expr
, ANTIC_IN (block
), NULL
,
3452 /* eprime will generally only be NULL if the
3453 value of the expression, translated
3454 through the PHI for this predecessor, is
3455 undefined. If that is the case, we can't
3456 make the expression fully redundant,
3457 because its value is undefined along a
3458 predecessor path. We can thus break out
3459 early because it doesn't matter what the
3460 rest of the results are. */
3467 eprime
= fully_constant_expression (eprime
);
3468 vprime
= get_expr_value_id (eprime
);
3469 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3471 if (edoubleprime
== NULL
)
3473 avail
[bprime
->index
] = eprime
;
3478 avail
[bprime
->index
] = edoubleprime
;
3480 if (first_s
== NULL
)
3481 first_s
= edoubleprime
;
3482 else if (!pre_expr_eq (first_s
, edoubleprime
))
3486 /* If we can insert it, it's not the same value
3487 already existing along every predecessor, and
3488 it's defined by some predecessor, it is
3489 partially redundant. */
3490 if (!cant_insert
&& !all_same
&& by_some
&& dbg_cnt (treepre_insert
))
3492 if (insert_into_preds_of_block (block
, get_expression_id (expr
),
3496 /* If all edges produce the same value and that value is
3497 an invariant, then the PHI has the same value on all
3498 edges. Note this. */
3499 else if (!cant_insert
&& all_same
&& eprime
3500 && (edoubleprime
->kind
== CONSTANT
3501 || edoubleprime
->kind
== NAME
)
3502 && !value_id_constant_p (val
))
3506 bitmap_set_t exprset
= VEC_index (bitmap_set_t
,
3507 value_expressions
, val
);
3509 unsigned int new_val
= get_expr_value_id (edoubleprime
);
3510 FOR_EACH_EXPR_ID_IN_SET (exprset
, j
, bi
)
3512 pre_expr expr
= expression_for_id (j
);
3514 if (expr
->kind
== NAME
)
3516 vn_ssa_aux_t info
= VN_INFO (PRE_EXPR_NAME (expr
));
3517 /* Just reset the value id and valnum so it is
3518 the same as the constant we have discovered. */
3519 if (edoubleprime
->kind
== CONSTANT
)
3521 info
->valnum
= PRE_EXPR_CONSTANT (edoubleprime
);
3522 pre_stats
.constified
++;
3525 info
->valnum
= VN_INFO (PRE_EXPR_NAME (edoubleprime
))->valnum
;
3526 info
->value_id
= new_val
;
3534 VEC_free (pre_expr
, heap
, exprs
);
3539 /* Perform insertion for partially anticipatable expressions. There
3540 is only one case we will perform insertion for these. This case is
3541 if the expression is partially anticipatable, and fully available.
3542 In this case, we know that putting it earlier will enable us to
3543 remove the later computation. */
3547 do_partial_partial_insertion (basic_block block
, basic_block dom
)
3549 bool new_stuff
= false;
3550 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (PA_IN (block
));
3554 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
3556 if (expr
->kind
!= NAME
)
3561 bool cant_insert
= false;
3564 pre_expr eprime
= NULL
;
3567 val
= get_expr_value_id (expr
);
3568 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3570 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3573 avail
= XCNEWVEC (pre_expr
, last_basic_block
);
3574 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3576 unsigned int vprime
;
3577 pre_expr edoubleprime
;
3579 /* We should never run insertion for the exit block
3580 and so not come across fake pred edges. */
3581 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3583 eprime
= phi_translate (expr
, ANTIC_IN (block
),
3587 /* eprime will generally only be NULL if the
3588 value of the expression, translated
3589 through the PHI for this predecessor, is
3590 undefined. If that is the case, we can't
3591 make the expression fully redundant,
3592 because its value is undefined along a
3593 predecessor path. We can thus break out
3594 early because it doesn't matter what the
3595 rest of the results are. */
3602 eprime
= fully_constant_expression (eprime
);
3603 vprime
= get_expr_value_id (eprime
);
3604 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3606 if (edoubleprime
== NULL
)
3612 avail
[bprime
->index
] = edoubleprime
;
3616 /* If we can insert it, it's not the same value
3617 already existing along every predecessor, and
3618 it's defined by some predecessor, it is
3619 partially redundant. */
3620 if (!cant_insert
&& by_all
&& dbg_cnt (treepre_insert
))
3622 pre_stats
.pa_insert
++;
3623 if (insert_into_preds_of_block (block
, get_expression_id (expr
),
3631 VEC_free (pre_expr
, heap
, exprs
);
3636 insert_aux (basic_block block
)
3639 bool new_stuff
= false;
3644 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3649 bitmap_set_t newset
= NEW_SETS (dom
);
3652 /* Note that we need to value_replace both NEW_SETS, and
3653 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3654 represented by some non-simple expression here that we want
3655 to replace it with. */
3656 FOR_EACH_EXPR_ID_IN_SET (newset
, i
, bi
)
3658 pre_expr expr
= expression_for_id (i
);
3659 bitmap_value_replace_in_set (NEW_SETS (block
), expr
);
3660 bitmap_value_replace_in_set (AVAIL_OUT (block
), expr
);
3663 if (!single_pred_p (block
))
3665 new_stuff
|= do_regular_insertion (block
, dom
);
3666 if (do_partial_partial
)
3667 new_stuff
|= do_partial_partial_insertion (block
, dom
);
3671 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3673 son
= next_dom_son (CDI_DOMINATORS
, son
))
3675 new_stuff
|= insert_aux (son
);
3681 /* Perform insertion of partially redundant values. */
3686 bool new_stuff
= true;
3688 int num_iterations
= 0;
3691 NEW_SETS (bb
) = bitmap_set_new ();
3696 new_stuff
= insert_aux (ENTRY_BLOCK_PTR
);
3698 statistics_histogram_event (cfun
, "insert iterations", num_iterations
);
3702 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3705 add_to_exp_gen (basic_block block
, tree op
)
3710 if (TREE_CODE (op
) == SSA_NAME
&& ssa_undefined_value_p (op
))
3712 result
= get_or_alloc_expr_for_name (op
);
3713 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3714 bitmap_value_insert_into_set (maximal_set
, result
);
3718 /* Create value ids for PHI in BLOCK. */
3721 make_values_for_phi (gimple phi
, basic_block block
)
3723 tree result
= gimple_phi_result (phi
);
3725 /* We have no need for virtual phis, as they don't represent
3726 actual computations. */
3727 if (is_gimple_reg (result
))
3729 pre_expr e
= get_or_alloc_expr_for_name (result
);
3730 add_to_value (get_expr_value_id (e
), e
);
3731 bitmap_insert_into_set (PHI_GEN (block
), e
);
3732 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3736 for (i
= 0; i
< gimple_phi_num_args (phi
); ++i
)
3738 tree arg
= gimple_phi_arg_def (phi
, i
);
3739 if (TREE_CODE (arg
) == SSA_NAME
)
3741 e
= get_or_alloc_expr_for_name (arg
);
3742 add_to_value (get_expr_value_id (e
), e
);
3743 bitmap_value_insert_into_set (maximal_set
, e
);
3750 /* Compute the AVAIL set for all basic blocks.
3752 This function performs value numbering of the statements in each basic
3753 block. The AVAIL sets are built from information we glean while doing
3754 this value numbering, since the AVAIL sets contain only one entry per
3757 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3758 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3761 compute_avail (void)
3764 basic_block block
, son
;
3765 basic_block
*worklist
;
3769 /* We pretend that default definitions are defined in the entry block.
3770 This includes function arguments and the static chain decl. */
3771 for (i
= 1; i
< num_ssa_names
; ++i
)
3773 tree name
= ssa_name (i
);
3776 || !SSA_NAME_IS_DEFAULT_DEF (name
)
3777 || has_zero_uses (name
)
3778 || !is_gimple_reg (name
))
3781 e
= get_or_alloc_expr_for_name (name
);
3782 add_to_value (get_expr_value_id (e
), e
);
3785 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR
), e
);
3786 bitmap_value_insert_into_set (maximal_set
, e
);
3788 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR
), e
);
3791 /* Allocate the worklist. */
3792 worklist
= XNEWVEC (basic_block
, n_basic_blocks
);
3794 /* Seed the algorithm by putting the dominator children of the entry
3795 block on the worklist. */
3796 for (son
= first_dom_son (CDI_DOMINATORS
, ENTRY_BLOCK_PTR
);
3798 son
= next_dom_son (CDI_DOMINATORS
, son
))
3799 worklist
[sp
++] = son
;
3801 /* Loop until the worklist is empty. */
3804 gimple_stmt_iterator gsi
;
3807 unsigned int stmt_uid
= 1;
3809 /* Pick a block from the worklist. */
3810 block
= worklist
[--sp
];
3812 /* Initially, the set of available values in BLOCK is that of
3813 its immediate dominator. */
3814 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3816 bitmap_set_copy (AVAIL_OUT (block
), AVAIL_OUT (dom
));
3818 /* Generate values for PHI nodes. */
3819 for (gsi
= gsi_start_phis (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3820 make_values_for_phi (gsi_stmt (gsi
), block
);
3822 /* Now compute value numbers and populate value sets with all
3823 the expressions computed in BLOCK. */
3824 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3829 stmt
= gsi_stmt (gsi
);
3830 gimple_set_uid (stmt
, stmt_uid
++);
3832 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
3834 pre_expr e
= get_or_alloc_expr_for_name (op
);
3836 add_to_value (get_expr_value_id (e
), e
);
3838 bitmap_insert_into_set (TMP_GEN (block
), e
);
3839 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3842 if (gimple_has_volatile_ops (stmt
)
3843 || stmt_could_throw_p (stmt
))
3846 switch (gimple_code (stmt
))
3849 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3850 add_to_exp_gen (block
, op
);
3857 vn_reference_op_t vro
;
3858 pre_expr result
= NULL
;
3859 VEC(vn_reference_op_s
, heap
) *ops
= NULL
;
3861 if (!can_value_number_call (stmt
))
3864 copy_reference_ops_from_call (stmt
, &ops
);
3865 vn_reference_lookup_pieces (gimple_vuse (stmt
), 0,
3866 gimple_expr_type (stmt
),
3868 VEC_free (vn_reference_op_s
, heap
, ops
);
3872 for (i
= 0; VEC_iterate (vn_reference_op_s
,
3876 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
3877 add_to_exp_gen (block
, vro
->op0
);
3878 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
3879 add_to_exp_gen (block
, vro
->op1
);
3880 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
3881 add_to_exp_gen (block
, vro
->op2
);
3883 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3884 result
->kind
= REFERENCE
;
3886 PRE_EXPR_REFERENCE (result
) = ref
;
3888 get_or_alloc_expression_id (result
);
3889 add_to_value (get_expr_value_id (result
), result
);
3892 bitmap_value_insert_into_set (EXP_GEN (block
),
3894 bitmap_value_insert_into_set (maximal_set
, result
);
3901 pre_expr result
= NULL
;
3902 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)))
3905 if (is_exception_related (stmt
))
3908 case tcc_comparison
:
3913 vn_nary_op_lookup_pieces (gimple_num_ops (stmt
) - 1,
3914 gimple_assign_rhs_code (stmt
),
3915 gimple_expr_type (stmt
),
3916 gimple_assign_rhs1 (stmt
),
3917 gimple_assign_rhs2 (stmt
),
3918 NULL_TREE
, NULL_TREE
, &nary
);
3923 for (i
= 0; i
< nary
->length
; i
++)
3924 if (TREE_CODE (nary
->op
[i
]) == SSA_NAME
)
3925 add_to_exp_gen (block
, nary
->op
[i
]);
3927 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3928 result
->kind
= NARY
;
3930 PRE_EXPR_NARY (result
) = nary
;
3934 case tcc_declaration
:
3939 vn_reference_op_t vro
;
3941 vn_reference_lookup (gimple_assign_rhs1 (stmt
),
3947 for (i
= 0; VEC_iterate (vn_reference_op_s
,
3951 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
3952 add_to_exp_gen (block
, vro
->op0
);
3953 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
3954 add_to_exp_gen (block
, vro
->op1
);
3955 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
3956 add_to_exp_gen (block
, vro
->op2
);
3958 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3959 result
->kind
= REFERENCE
;
3961 PRE_EXPR_REFERENCE (result
) = ref
;
3966 /* For any other statement that we don't
3967 recognize, simply add all referenced
3968 SSA_NAMEs to EXP_GEN. */
3969 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3970 add_to_exp_gen (block
, op
);
3974 get_or_alloc_expression_id (result
);
3975 add_to_value (get_expr_value_id (result
), result
);
3978 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3979 bitmap_value_insert_into_set (maximal_set
, result
);
3989 /* Put the dominator children of BLOCK on the worklist of blocks
3990 to compute available sets for. */
3991 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3993 son
= next_dom_son (CDI_DOMINATORS
, son
))
3994 worklist
[sp
++] = son
;
4000 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
4001 than the available expressions for it. The insertion point is
4002 right before the first use in STMT. Returns the SSA_NAME that should
4003 be used for replacement. */
4006 do_SCCVN_insertion (gimple stmt
, tree ssa_vn
)
4008 basic_block bb
= gimple_bb (stmt
);
4009 gimple_stmt_iterator gsi
;
4010 gimple_seq stmts
= NULL
;
4014 /* First create a value expression from the expression we want
4015 to insert and associate it with the value handle for SSA_VN. */
4016 e
= get_or_alloc_expr_for (vn_get_expr_for (ssa_vn
));
4020 /* Then use create_expression_by_pieces to generate a valid
4021 expression to insert at this point of the IL stream. */
4022 expr
= create_expression_by_pieces (bb
, e
, &stmts
, stmt
, NULL
);
4023 if (expr
== NULL_TREE
)
4025 gsi
= gsi_for_stmt (stmt
);
4026 gsi_insert_seq_before (&gsi
, stmts
, GSI_SAME_STMT
);
4031 /* Eliminate fully redundant computations. */
4036 VEC (gimple
, heap
) *to_remove
= NULL
;
4038 unsigned int todo
= 0;
4039 gimple_stmt_iterator gsi
;
4045 for (gsi
= gsi_start_bb (b
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4047 stmt
= gsi_stmt (gsi
);
4049 /* Lookup the RHS of the expression, see if we have an
4050 available computation for it. If so, replace the RHS with
4051 the available computation. */
4052 if (gimple_has_lhs (stmt
)
4053 && TREE_CODE (gimple_get_lhs (stmt
)) == SSA_NAME
4054 && !gimple_assign_ssa_name_copy_p (stmt
)
4055 && (!gimple_assign_single_p (stmt
)
4056 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
4057 && !gimple_has_volatile_ops (stmt
)
4058 && !has_zero_uses (gimple_get_lhs (stmt
)))
4060 tree lhs
= gimple_get_lhs (stmt
);
4061 tree rhs
= NULL_TREE
;
4063 pre_expr lhsexpr
= get_or_alloc_expr_for_name (lhs
);
4064 pre_expr sprimeexpr
;
4066 if (gimple_assign_single_p (stmt
))
4067 rhs
= gimple_assign_rhs1 (stmt
);
4069 sprimeexpr
= bitmap_find_leader (AVAIL_OUT (b
),
4070 get_expr_value_id (lhsexpr
),
4075 if (sprimeexpr
->kind
== CONSTANT
)
4076 sprime
= PRE_EXPR_CONSTANT (sprimeexpr
);
4077 else if (sprimeexpr
->kind
== NAME
)
4078 sprime
= PRE_EXPR_NAME (sprimeexpr
);
4083 /* If there is no existing leader but SCCVN knows this
4084 value is constant, use that constant. */
4085 if (!sprime
&& is_gimple_min_invariant (VN_INFO (lhs
)->valnum
))
4087 sprime
= VN_INFO (lhs
)->valnum
;
4088 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
4089 TREE_TYPE (sprime
)))
4090 sprime
= fold_convert (TREE_TYPE (lhs
), sprime
);
4092 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4094 fprintf (dump_file
, "Replaced ");
4095 print_gimple_expr (dump_file
, stmt
, 0, 0);
4096 fprintf (dump_file
, " with ");
4097 print_generic_expr (dump_file
, sprime
, 0);
4098 fprintf (dump_file
, " in ");
4099 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4101 pre_stats
.eliminations
++;
4102 propagate_tree_value_into_stmt (&gsi
, sprime
);
4103 stmt
= gsi_stmt (gsi
);
4108 /* If there is no existing usable leader but SCCVN thinks
4109 it has an expression it wants to use as replacement,
4111 if (!sprime
|| sprime
== lhs
)
4113 tree val
= VN_INFO (lhs
)->valnum
;
4115 && TREE_CODE (val
) == SSA_NAME
4116 && VN_INFO (val
)->needs_insertion
4117 && can_PRE_operation (vn_get_expr_for (val
)))
4118 sprime
= do_SCCVN_insertion (stmt
, val
);
4122 && (rhs
== NULL_TREE
4123 || TREE_CODE (rhs
) != SSA_NAME
4124 || may_propagate_copy (rhs
, sprime
)))
4126 gcc_assert (sprime
!= rhs
);
4128 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4130 fprintf (dump_file
, "Replaced ");
4131 print_gimple_expr (dump_file
, stmt
, 0, 0);
4132 fprintf (dump_file
, " with ");
4133 print_generic_expr (dump_file
, sprime
, 0);
4134 fprintf (dump_file
, " in ");
4135 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4138 if (TREE_CODE (sprime
) == SSA_NAME
)
4139 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4141 /* We need to make sure the new and old types actually match,
4142 which may require adding a simple cast, which fold_convert
4144 if ((!rhs
|| TREE_CODE (rhs
) != SSA_NAME
)
4145 && !useless_type_conversion_p (gimple_expr_type (stmt
),
4146 TREE_TYPE (sprime
)))
4147 sprime
= fold_convert (gimple_expr_type (stmt
), sprime
);
4149 pre_stats
.eliminations
++;
4150 propagate_tree_value_into_stmt (&gsi
, sprime
);
4151 stmt
= gsi_stmt (gsi
);
4154 /* If we removed EH side effects from the statement, clean
4155 its EH information. */
4156 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4158 bitmap_set_bit (need_eh_cleanup
,
4159 gimple_bb (stmt
)->index
);
4160 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4161 fprintf (dump_file
, " Removed EH side effects.\n");
4165 /* If the statement is a scalar store, see if the expression
4166 has the same value number as its rhs. If so, the store is
4168 else if (gimple_assign_single_p (stmt
)
4169 && !is_gimple_reg (gimple_assign_lhs (stmt
))
4170 && (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
4171 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt
))))
4173 tree rhs
= gimple_assign_rhs1 (stmt
);
4175 val
= vn_reference_lookup (gimple_assign_lhs (stmt
),
4176 gimple_vuse (stmt
), true, NULL
);
4177 if (TREE_CODE (rhs
) == SSA_NAME
)
4178 rhs
= VN_INFO (rhs
)->valnum
;
4180 && operand_equal_p (val
, rhs
, 0))
4182 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4184 fprintf (dump_file
, "Deleted redundant store ");
4185 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4188 /* Queue stmt for removal. */
4189 VEC_safe_push (gimple
, heap
, to_remove
, stmt
);
4192 /* Visit COND_EXPRs and fold the comparison with the
4193 available value-numbers. */
4194 else if (gimple_code (stmt
) == GIMPLE_COND
)
4196 tree op0
= gimple_cond_lhs (stmt
);
4197 tree op1
= gimple_cond_rhs (stmt
);
4200 if (TREE_CODE (op0
) == SSA_NAME
)
4201 op0
= VN_INFO (op0
)->valnum
;
4202 if (TREE_CODE (op1
) == SSA_NAME
)
4203 op1
= VN_INFO (op1
)->valnum
;
4204 result
= fold_binary (gimple_cond_code (stmt
), boolean_type_node
,
4206 if (result
&& TREE_CODE (result
) == INTEGER_CST
)
4208 if (integer_zerop (result
))
4209 gimple_cond_make_false (stmt
);
4211 gimple_cond_make_true (stmt
);
4213 todo
= TODO_cleanup_cfg
;
4216 /* Visit indirect calls and turn them into direct calls if
4218 if (gimple_code (stmt
) == GIMPLE_CALL
4219 && TREE_CODE (gimple_call_fn (stmt
)) == SSA_NAME
)
4221 tree fn
= VN_INFO (gimple_call_fn (stmt
))->valnum
;
4222 if (TREE_CODE (fn
) == ADDR_EXPR
4223 && TREE_CODE (TREE_OPERAND (fn
, 0)) == FUNCTION_DECL
)
4225 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4227 fprintf (dump_file
, "Replacing call target with ");
4228 print_generic_expr (dump_file
, fn
, 0);
4229 fprintf (dump_file
, " in ");
4230 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4233 gimple_call_set_fn (stmt
, fn
);
4235 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4237 bitmap_set_bit (need_eh_cleanup
,
4238 gimple_bb (stmt
)->index
);
4239 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4240 fprintf (dump_file
, " Removed EH side effects.\n");
4243 /* Changing an indirect call to a direct call may
4244 have exposed different semantics. This may
4245 require an SSA update. */
4246 todo
|= TODO_update_ssa_only_virtuals
;
4251 for (gsi
= gsi_start_phis (b
); !gsi_end_p (gsi
);)
4253 gimple stmt
, phi
= gsi_stmt (gsi
);
4254 tree sprime
= NULL_TREE
, res
= PHI_RESULT (phi
);
4255 pre_expr sprimeexpr
, resexpr
;
4256 gimple_stmt_iterator gsi2
;
4258 /* We want to perform redundant PHI elimination. Do so by
4259 replacing the PHI with a single copy if possible.
4260 Do not touch inserted, single-argument or virtual PHIs. */
4261 if (gimple_phi_num_args (phi
) == 1
4262 || !is_gimple_reg (res
)
4263 || bitmap_bit_p (inserted_phi_names
, SSA_NAME_VERSION (res
)))
4269 resexpr
= get_or_alloc_expr_for_name (res
);
4270 sprimeexpr
= bitmap_find_leader (AVAIL_OUT (b
),
4271 get_expr_value_id (resexpr
), NULL
);
4274 if (sprimeexpr
->kind
== CONSTANT
)
4275 sprime
= PRE_EXPR_CONSTANT (sprimeexpr
);
4276 else if (sprimeexpr
->kind
== NAME
)
4277 sprime
= PRE_EXPR_NAME (sprimeexpr
);
4288 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4290 fprintf (dump_file
, "Replaced redundant PHI node defining ");
4291 print_generic_expr (dump_file
, res
, 0);
4292 fprintf (dump_file
, " with ");
4293 print_generic_expr (dump_file
, sprime
, 0);
4294 fprintf (dump_file
, "\n");
4297 remove_phi_node (&gsi
, false);
4299 if (!useless_type_conversion_p (TREE_TYPE (res
), TREE_TYPE (sprime
)))
4300 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4301 stmt
= gimple_build_assign (res
, sprime
);
4302 SSA_NAME_DEF_STMT (res
) = stmt
;
4303 if (TREE_CODE (sprime
) == SSA_NAME
)
4304 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4306 gsi2
= gsi_after_labels (b
);
4307 gsi_insert_before (&gsi2
, stmt
, GSI_NEW_STMT
);
4308 /* Queue the copy for eventual removal. */
4309 VEC_safe_push (gimple
, heap
, to_remove
, stmt
);
4310 pre_stats
.eliminations
++;
4314 /* We cannot remove stmts during BB walk, especially not release SSA
4315 names there as this confuses the VN machinery. The stmts ending
4316 up in to_remove are either stores or simple copies. */
4317 for (i
= 0; VEC_iterate (gimple
, to_remove
, i
, stmt
); ++i
)
4319 tree lhs
= gimple_assign_lhs (stmt
);
4320 use_operand_p use_p
;
4323 /* If there is a single use only, propagate the equivalency
4324 instead of keeping the copy. */
4325 if (TREE_CODE (lhs
) == SSA_NAME
4326 && single_imm_use (lhs
, &use_p
, &use_stmt
)
4327 && may_propagate_copy (USE_FROM_PTR (use_p
),
4328 gimple_assign_rhs1 (stmt
)))
4330 SET_USE (use_p
, gimple_assign_rhs1 (stmt
));
4331 update_stmt (use_stmt
);
4334 /* If this is a store or a now unused copy, remove it. */
4335 if (TREE_CODE (lhs
) != SSA_NAME
4336 || has_zero_uses (lhs
))
4338 gsi
= gsi_for_stmt (stmt
);
4339 unlink_stmt_vdef (stmt
);
4340 gsi_remove (&gsi
, true);
4341 release_defs (stmt
);
4344 VEC_free (gimple
, heap
, to_remove
);
4349 /* Borrow a bit of tree-ssa-dce.c for the moment.
4350 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4351 this may be a bit faster, and we may want critical edges kept split. */
4353 /* If OP's defining statement has not already been determined to be necessary,
4354 mark that statement necessary. Return the stmt, if it is newly
4357 static inline gimple
4358 mark_operand_necessary (tree op
)
4364 if (TREE_CODE (op
) != SSA_NAME
)
4367 stmt
= SSA_NAME_DEF_STMT (op
);
4370 if (gimple_plf (stmt
, NECESSARY
)
4371 || gimple_nop_p (stmt
))
4374 gimple_set_plf (stmt
, NECESSARY
, true);
4378 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4379 to insert PHI nodes sometimes, and because value numbering of casts isn't
4380 perfect, we sometimes end up inserting dead code. This simple DCE-like
4381 pass removes any insertions we made that weren't actually used. */
4384 remove_dead_inserted_code (void)
4386 VEC(gimple
,heap
) *worklist
= NULL
;
4390 worklist
= VEC_alloc (gimple
, heap
, VEC_length (gimple
, inserted_exprs
));
4391 for (i
= 0; VEC_iterate (gimple
, inserted_exprs
, i
, t
); i
++)
4393 if (gimple_plf (t
, NECESSARY
))
4394 VEC_quick_push (gimple
, worklist
, t
);
4396 while (VEC_length (gimple
, worklist
) > 0)
4398 t
= VEC_pop (gimple
, worklist
);
4400 /* PHI nodes are somewhat special in that each PHI alternative has
4401 data and control dependencies. All the statements feeding the
4402 PHI node's arguments are always necessary. */
4403 if (gimple_code (t
) == GIMPLE_PHI
)
4407 VEC_reserve (gimple
, heap
, worklist
, gimple_phi_num_args (t
));
4408 for (k
= 0; k
< gimple_phi_num_args (t
); k
++)
4410 tree arg
= PHI_ARG_DEF (t
, k
);
4411 if (TREE_CODE (arg
) == SSA_NAME
)
4413 gimple n
= mark_operand_necessary (arg
);
4415 VEC_quick_push (gimple
, worklist
, n
);
4421 /* Propagate through the operands. Examine all the USE, VUSE and
4422 VDEF operands in this statement. Mark all the statements
4423 which feed this statement's uses as necessary. */
4427 /* The operands of VDEF expressions are also needed as they
4428 represent potential definitions that may reach this
4429 statement (VDEF operands allow us to follow def-def
4432 FOR_EACH_SSA_TREE_OPERAND (use
, t
, iter
, SSA_OP_ALL_USES
)
4434 gimple n
= mark_operand_necessary (use
);
4436 VEC_safe_push (gimple
, heap
, worklist
, n
);
4441 for (i
= 0; VEC_iterate (gimple
, inserted_exprs
, i
, t
); i
++)
4443 if (!gimple_plf (t
, NECESSARY
))
4445 gimple_stmt_iterator gsi
;
4447 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4449 fprintf (dump_file
, "Removing unnecessary insertion:");
4450 print_gimple_stmt (dump_file
, t
, 0, 0);
4453 gsi
= gsi_for_stmt (t
);
4454 if (gimple_code (t
) == GIMPLE_PHI
)
4455 remove_phi_node (&gsi
, true);
4457 gsi_remove (&gsi
, true);
4461 VEC_free (gimple
, heap
, worklist
);
4464 /* Initialize data structures used by PRE. */
4467 init_pre (bool do_fre
)
4471 next_expression_id
= 1;
4473 VEC_safe_push (pre_expr
, heap
, expressions
, NULL
);
4474 value_expressions
= VEC_alloc (bitmap_set_t
, heap
, get_max_value_id () + 1);
4475 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
4476 get_max_value_id() + 1);
4480 inserted_exprs
= NULL
;
4481 need_creation
= NULL
;
4482 pretemp
= NULL_TREE
;
4483 storetemp
= NULL_TREE
;
4484 prephitemp
= NULL_TREE
;
4486 connect_infinite_loops_to_exit ();
4487 memset (&pre_stats
, 0, sizeof (pre_stats
));
4490 postorder
= XNEWVEC (int, n_basic_blocks
- NUM_FIXED_BLOCKS
);
4491 post_order_compute (postorder
, false, false);
4494 bb
->aux
= XCNEWVEC (struct bb_bitmap_sets
, 1);
4496 calculate_dominance_info (CDI_POST_DOMINATORS
);
4497 calculate_dominance_info (CDI_DOMINATORS
);
4499 bitmap_obstack_initialize (&grand_bitmap_obstack
);
4500 inserted_phi_names
= BITMAP_ALLOC (&grand_bitmap_obstack
);
4501 phi_translate_table
= htab_create (5110, expr_pred_trans_hash
,
4502 expr_pred_trans_eq
, free
);
4503 expression_to_id
= htab_create (num_ssa_names
* 3,
4506 seen_during_translate
= BITMAP_ALLOC (&grand_bitmap_obstack
);
4507 bitmap_set_pool
= create_alloc_pool ("Bitmap sets",
4508 sizeof (struct bitmap_set
), 30);
4509 pre_expr_pool
= create_alloc_pool ("pre_expr nodes",
4510 sizeof (struct pre_expr_d
), 30);
4513 EXP_GEN (bb
) = bitmap_set_new ();
4514 PHI_GEN (bb
) = bitmap_set_new ();
4515 TMP_GEN (bb
) = bitmap_set_new ();
4516 AVAIL_OUT (bb
) = bitmap_set_new ();
4518 maximal_set
= in_fre
? NULL
: bitmap_set_new ();
4520 need_eh_cleanup
= BITMAP_ALLOC (NULL
);
4524 /* Deallocate data structures used by PRE. */
4527 fini_pre (bool do_fre
)
4532 VEC_free (bitmap_set_t
, heap
, value_expressions
);
4533 VEC_free (gimple
, heap
, inserted_exprs
);
4534 VEC_free (gimple
, heap
, need_creation
);
4535 bitmap_obstack_release (&grand_bitmap_obstack
);
4536 free_alloc_pool (bitmap_set_pool
);
4537 free_alloc_pool (pre_expr_pool
);
4538 htab_delete (phi_translate_table
);
4539 htab_delete (expression_to_id
);
4547 free_dominance_info (CDI_POST_DOMINATORS
);
4549 if (!bitmap_empty_p (need_eh_cleanup
))
4551 gimple_purge_all_dead_eh_edges (need_eh_cleanup
);
4552 cleanup_tree_cfg ();
4555 BITMAP_FREE (need_eh_cleanup
);
4558 loop_optimizer_finalize ();
4561 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4562 only wants to do full redundancy elimination. */
4565 execute_pre (bool do_fre ATTRIBUTE_UNUSED
)
4567 unsigned int todo
= 0;
4569 do_partial_partial
= optimize
> 2;
4571 /* This has to happen before SCCVN runs because
4572 loop_optimizer_init may create new phis, etc. */
4574 loop_optimizer_init (LOOPS_NORMAL
);
4576 if (!run_scc_vn (do_fre
))
4580 remove_dead_inserted_code ();
4581 loop_optimizer_finalize ();
4590 /* Collect and value number expressions computed in each basic block. */
4593 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4599 print_bitmap_set (dump_file
, EXP_GEN (bb
), "exp_gen", bb
->index
);
4600 print_bitmap_set (dump_file
, PHI_GEN (bb
), "phi_gen", bb
->index
);
4601 print_bitmap_set (dump_file
, TMP_GEN (bb
), "tmp_gen", bb
->index
);
4602 print_bitmap_set (dump_file
, AVAIL_OUT (bb
), "avail_out", bb
->index
);
4605 print_bitmap_set (dump_file
, maximal_set
, "maximal", 0);
4608 /* Insert can get quite slow on an incredibly large number of basic
4609 blocks due to some quadratic behavior. Until this behavior is
4610 fixed, don't run it when he have an incredibly large number of
4611 bb's. If we aren't going to run insert, there is no point in
4612 computing ANTIC, either, even though it's plenty fast. */
4613 if (!do_fre
&& n_basic_blocks
< 4000)
4619 /* Remove all the redundant expressions. */
4620 todo
|= eliminate ();
4622 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4623 statistics_counter_event (cfun
, "PA inserted", pre_stats
.pa_insert
);
4624 statistics_counter_event (cfun
, "New PHIs", pre_stats
.phis
);
4625 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4626 statistics_counter_event (cfun
, "Constified", pre_stats
.constified
);
4628 /* Make sure to remove fake edges before committing our inserts.
4629 This makes sure we don't end up with extra critical edges that
4630 we would need to split. */
4631 remove_fake_exit_edges ();
4632 gsi_commit_edge_inserts ();
4634 clear_expression_ids ();
4637 remove_dead_inserted_code ();
4645 /* Gate and execute functions for PRE. */
4650 return execute_pre (false);
4656 /* PRE tends to generate bigger code. */
4657 return flag_tree_pre
!= 0 && optimize_function_for_speed_p (cfun
);
4660 struct gimple_opt_pass pass_pre
=
4665 gate_pre
, /* gate */
4666 do_pre
, /* execute */
4669 0, /* static_pass_number */
4670 TV_TREE_PRE
, /* tv_id */
4671 PROP_no_crit_edges
| PROP_cfg
4672 | PROP_ssa
, /* properties_required */
4673 0, /* properties_provided */
4674 0, /* properties_destroyed */
4675 TODO_rebuild_alias
, /* todo_flags_start */
4676 TODO_update_ssa_only_virtuals
| TODO_dump_func
| TODO_ggc_collect
4677 | TODO_verify_ssa
/* todo_flags_finish */
4682 /* Gate and execute functions for FRE. */
4687 return execute_pre (true);
4693 return flag_tree_fre
!= 0;
4696 struct gimple_opt_pass pass_fre
=
4701 gate_fre
, /* gate */
4702 execute_fre
, /* execute */
4705 0, /* static_pass_number */
4706 TV_TREE_FRE
, /* tv_id */
4707 PROP_cfg
| PROP_ssa
, /* properties_required */
4708 0, /* properties_provided */
4709 0, /* properties_destroyed */
4710 0, /* todo_flags_start */
4711 TODO_dump_func
| TODO_ggc_collect
| TODO_verify_ssa
/* todo_flags_finish */