2 Copyright (C) 2001-2013 Free Software Foundation, Inc.
3 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
27 #include "basic-block.h"
28 #include "gimple-pretty-print.h"
29 #include "tree-inline.h"
32 #include "hash-table.h"
33 #include "tree-iterator.h"
34 #include "alloc-pool.h"
36 #include "tree-pass.h"
39 #include "langhooks.h"
41 #include "tree-ssa-sccvn.h"
42 #include "tree-scalar-evolution.h"
50 1. Avail sets can be shared by making an avail_find_leader that
51 walks up the dominator tree and looks in those avail sets.
52 This might affect code optimality, it's unclear right now.
53 2. Strength reduction can be performed by anticipating expressions
54 we can repair later on.
55 3. We can do back-substitution or smarter value numbering to catch
56 commutative expressions split up over multiple statements.
59 /* For ease of terminology, "expression node" in the below refers to
60 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
61 represent the actual statement containing the expressions we care about,
62 and we cache the value number by putting it in the expression. */
66 First we walk the statements to generate the AVAIL sets, the
67 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
68 generation of values/expressions by a given block. We use them
69 when computing the ANTIC sets. The AVAIL sets consist of
70 SSA_NAME's that represent values, so we know what values are
71 available in what blocks. AVAIL is a forward dataflow problem. In
72 SSA, values are never killed, so we don't need a kill set, or a
73 fixpoint iteration, in order to calculate the AVAIL sets. In
74 traditional parlance, AVAIL sets tell us the downsafety of the
77 Next, we generate the ANTIC sets. These sets represent the
78 anticipatable expressions. ANTIC is a backwards dataflow
79 problem. An expression is anticipatable in a given block if it could
80 be generated in that block. This means that if we had to perform
81 an insertion in that block, of the value of that expression, we
82 could. Calculating the ANTIC sets requires phi translation of
83 expressions, because the flow goes backwards through phis. We must
84 iterate to a fixpoint of the ANTIC sets, because we have a kill
85 set. Even in SSA form, values are not live over the entire
86 function, only from their definition point onwards. So we have to
87 remove values from the ANTIC set once we go past the definition
88 point of the leaders that make them up.
89 compute_antic/compute_antic_aux performs this computation.
91 Third, we perform insertions to make partially redundant
92 expressions fully redundant.
94 An expression is partially redundant (excluding partial
97 1. It is AVAIL in some, but not all, of the predecessors of a
99 2. It is ANTIC in all the predecessors.
101 In order to make it fully redundant, we insert the expression into
102 the predecessors where it is not available, but is ANTIC.
104 For the partial anticipation case, we only perform insertion if it
105 is partially anticipated in some block, and fully available in all
108 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
109 performs these steps.
111 Fourth, we eliminate fully redundant expressions.
112 This is a simple statement walk that replaces redundant
113 calculations with the now available values. */
115 /* Representations of value numbers:
117 Value numbers are represented by a representative SSA_NAME. We
118 will create fake SSA_NAME's in situations where we need a
119 representative but do not have one (because it is a complex
120 expression). In order to facilitate storing the value numbers in
121 bitmaps, and keep the number of wasted SSA_NAME's down, we also
122 associate a value_id with each value number, and create full blown
123 ssa_name's only where we actually need them (IE in operands of
124 existing expressions).
126 Theoretically you could replace all the value_id's with
127 SSA_NAME_VERSION, but this would allocate a large number of
128 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
129 It would also require an additional indirection at each point we
132 /* Representation of expressions on value numbers:
134 Expressions consisting of value numbers are represented the same
135 way as our VN internally represents them, with an additional
136 "pre_expr" wrapping around them in order to facilitate storing all
137 of the expressions in the same sets. */
139 /* Representation of sets:
141 The dataflow sets do not need to be sorted in any particular order
142 for the majority of their lifetime, are simply represented as two
143 bitmaps, one that keeps track of values present in the set, and one
144 that keeps track of expressions present in the set.
146 When we need them in topological order, we produce it on demand by
147 transforming the bitmap into an array and sorting it into topo
150 /* Type of expression, used to know which member of the PRE_EXPR union
161 typedef union pre_expr_union_d
166 vn_reference_t reference
;
169 typedef struct pre_expr_d
: typed_noop_remove
<pre_expr_d
>
171 enum pre_expr_kind kind
;
175 /* hash_table support. */
176 typedef pre_expr_d value_type
;
177 typedef pre_expr_d compare_type
;
178 static inline hashval_t
hash (const pre_expr_d
*);
179 static inline int equal (const pre_expr_d
*, const pre_expr_d
*);
182 #define PRE_EXPR_NAME(e) (e)->u.name
183 #define PRE_EXPR_NARY(e) (e)->u.nary
184 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
185 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
187 /* Compare E1 and E1 for equality. */
190 pre_expr_d::equal (const value_type
*e1
, const compare_type
*e2
)
192 if (e1
->kind
!= e2
->kind
)
198 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1
),
199 PRE_EXPR_CONSTANT (e2
));
201 return PRE_EXPR_NAME (e1
) == PRE_EXPR_NAME (e2
);
203 return vn_nary_op_eq (PRE_EXPR_NARY (e1
), PRE_EXPR_NARY (e2
));
205 return vn_reference_eq (PRE_EXPR_REFERENCE (e1
),
206 PRE_EXPR_REFERENCE (e2
));
215 pre_expr_d::hash (const value_type
*e
)
220 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e
));
222 return SSA_NAME_VERSION (PRE_EXPR_NAME (e
));
224 return PRE_EXPR_NARY (e
)->hashcode
;
226 return PRE_EXPR_REFERENCE (e
)->hashcode
;
232 /* Next global expression id number. */
233 static unsigned int next_expression_id
;
235 /* Mapping from expression to id number we can use in bitmap sets. */
236 static vec
<pre_expr
> expressions
;
237 static hash_table
<pre_expr_d
> expression_to_id
;
238 static vec
<unsigned> name_to_id
;
240 /* Allocate an expression id for EXPR. */
242 static inline unsigned int
243 alloc_expression_id (pre_expr expr
)
245 struct pre_expr_d
**slot
;
246 /* Make sure we won't overflow. */
247 gcc_assert (next_expression_id
+ 1 > next_expression_id
);
248 expr
->id
= next_expression_id
++;
249 expressions
.safe_push (expr
);
250 if (expr
->kind
== NAME
)
252 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
253 /* vec::safe_grow_cleared allocates no headroom. Avoid frequent
254 re-allocations by using vec::reserve upfront. There is no
255 vec::quick_grow_cleared unfortunately. */
256 unsigned old_len
= name_to_id
.length ();
257 name_to_id
.reserve (num_ssa_names
- old_len
);
258 name_to_id
.safe_grow_cleared (num_ssa_names
);
259 gcc_assert (name_to_id
[version
] == 0);
260 name_to_id
[version
] = expr
->id
;
264 slot
= expression_to_id
.find_slot (expr
, INSERT
);
268 return next_expression_id
- 1;
271 /* Return the expression id for tree EXPR. */
273 static inline unsigned int
274 get_expression_id (const pre_expr expr
)
279 static inline unsigned int
280 lookup_expression_id (const pre_expr expr
)
282 struct pre_expr_d
**slot
;
284 if (expr
->kind
== NAME
)
286 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
287 if (name_to_id
.length () <= version
)
289 return name_to_id
[version
];
293 slot
= expression_to_id
.find_slot (expr
, NO_INSERT
);
296 return ((pre_expr
)*slot
)->id
;
300 /* Return the existing expression id for EXPR, or create one if one
301 does not exist yet. */
303 static inline unsigned int
304 get_or_alloc_expression_id (pre_expr expr
)
306 unsigned int id
= lookup_expression_id (expr
);
308 return alloc_expression_id (expr
);
309 return expr
->id
= id
;
312 /* Return the expression that has expression id ID */
314 static inline pre_expr
315 expression_for_id (unsigned int id
)
317 return expressions
[id
];
320 /* Free the expression id field in all of our expressions,
321 and then destroy the expressions array. */
324 clear_expression_ids (void)
326 expressions
.release ();
329 static alloc_pool pre_expr_pool
;
331 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
334 get_or_alloc_expr_for_name (tree name
)
336 struct pre_expr_d expr
;
338 unsigned int result_id
;
342 PRE_EXPR_NAME (&expr
) = name
;
343 result_id
= lookup_expression_id (&expr
);
345 return expression_for_id (result_id
);
347 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
349 PRE_EXPR_NAME (result
) = name
;
350 alloc_expression_id (result
);
354 /* An unordered bitmap set. One bitmap tracks values, the other,
356 typedef struct bitmap_set
358 bitmap_head expressions
;
362 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
363 EXECUTE_IF_SET_IN_BITMAP(&(set)->expressions, 0, (id), (bi))
365 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
366 EXECUTE_IF_SET_IN_BITMAP(&(set)->values, 0, (id), (bi))
368 /* Mapping from value id to expressions with that value_id. */
369 static vec
<bitmap
> value_expressions
;
371 /* Sets that we need to keep track of. */
372 typedef struct bb_bitmap_sets
374 /* The EXP_GEN set, which represents expressions/values generated in
376 bitmap_set_t exp_gen
;
378 /* The PHI_GEN set, which represents PHI results generated in a
380 bitmap_set_t phi_gen
;
382 /* The TMP_GEN set, which represents results/temporaries generated
383 in a basic block. IE the LHS of an expression. */
384 bitmap_set_t tmp_gen
;
386 /* The AVAIL_OUT set, which represents which values are available in
387 a given basic block. */
388 bitmap_set_t avail_out
;
390 /* The ANTIC_IN set, which represents which values are anticipatable
391 in a given basic block. */
392 bitmap_set_t antic_in
;
394 /* The PA_IN set, which represents which values are
395 partially anticipatable in a given basic block. */
398 /* The NEW_SETS set, which is used during insertion to augment the
399 AVAIL_OUT set of blocks with the new insertions performed during
400 the current iteration. */
401 bitmap_set_t new_sets
;
403 /* A cache for value_dies_in_block_x. */
406 /* True if we have visited this block during ANTIC calculation. */
407 unsigned int visited
: 1;
409 /* True we have deferred processing this block during ANTIC
410 calculation until its successor is processed. */
411 unsigned int deferred
: 1;
413 /* True when the block contains a call that might not return. */
414 unsigned int contains_may_not_return_call
: 1;
417 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
418 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
419 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
420 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
421 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
422 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
423 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
424 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
425 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
426 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
427 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
430 /* Basic block list in postorder. */
431 static int *postorder
;
432 static int postorder_num
;
434 /* This structure is used to keep track of statistics on what
435 optimization PRE was able to perform. */
438 /* The number of RHS computations eliminated by PRE. */
441 /* The number of new expressions/temporaries generated by PRE. */
444 /* The number of inserts found due to partial anticipation */
447 /* The number of new PHI nodes added by PRE. */
451 static bool do_partial_partial
;
452 static pre_expr
bitmap_find_leader (bitmap_set_t
, unsigned int);
453 static void bitmap_value_insert_into_set (bitmap_set_t
, pre_expr
);
454 static void bitmap_value_replace_in_set (bitmap_set_t
, pre_expr
);
455 static void bitmap_set_copy (bitmap_set_t
, bitmap_set_t
);
456 static bool bitmap_set_contains_value (bitmap_set_t
, unsigned int);
457 static void bitmap_insert_into_set (bitmap_set_t
, pre_expr
);
458 static void bitmap_insert_into_set_1 (bitmap_set_t
, pre_expr
,
460 static bitmap_set_t
bitmap_set_new (void);
461 static tree
create_expression_by_pieces (basic_block
, pre_expr
, gimple_seq
*,
463 static tree
find_or_generate_expression (basic_block
, tree
, gimple_seq
*);
464 static unsigned int get_expr_value_id (pre_expr
);
466 /* We can add and remove elements and entries to and from sets
467 and hash tables, so we use alloc pools for them. */
469 static alloc_pool bitmap_set_pool
;
470 static bitmap_obstack grand_bitmap_obstack
;
472 /* Set of blocks with statements that have had their EH properties changed. */
473 static bitmap need_eh_cleanup
;
475 /* Set of blocks with statements that have had their AB properties changed. */
476 static bitmap need_ab_cleanup
;
478 /* A three tuple {e, pred, v} used to cache phi translations in the
479 phi_translate_table. */
481 typedef struct expr_pred_trans_d
: typed_free_remove
<expr_pred_trans_d
>
483 /* The expression. */
486 /* The predecessor block along which we translated the expression. */
489 /* The value that resulted from the translation. */
492 /* The hashcode for the expression, pred pair. This is cached for
496 /* hash_table support. */
497 typedef expr_pred_trans_d value_type
;
498 typedef expr_pred_trans_d compare_type
;
499 static inline hashval_t
hash (const value_type
*);
500 static inline int equal (const value_type
*, const compare_type
*);
501 } *expr_pred_trans_t
;
502 typedef const struct expr_pred_trans_d
*const_expr_pred_trans_t
;
505 expr_pred_trans_d::hash (const expr_pred_trans_d
*e
)
511 expr_pred_trans_d::equal (const value_type
*ve1
,
512 const compare_type
*ve2
)
514 basic_block b1
= ve1
->pred
;
515 basic_block b2
= ve2
->pred
;
517 /* If they are not translations for the same basic block, they can't
521 return pre_expr_d::equal (ve1
->e
, ve2
->e
);
524 /* The phi_translate_table caches phi translations for a given
525 expression and predecessor. */
526 static hash_table
<expr_pred_trans_d
> phi_translate_table
;
528 /* Search in the phi translation table for the translation of
529 expression E in basic block PRED.
530 Return the translated value, if found, NULL otherwise. */
532 static inline pre_expr
533 phi_trans_lookup (pre_expr e
, basic_block pred
)
535 expr_pred_trans_t
*slot
;
536 struct expr_pred_trans_d ept
;
540 ept
.hashcode
= iterative_hash_hashval_t (pre_expr_d::hash (e
), pred
->index
);
541 slot
= phi_translate_table
.find_slot_with_hash (&ept
, ept
.hashcode
,
550 /* Add the tuple mapping from {expression E, basic block PRED} to
551 value V, to the phi translation table. */
554 phi_trans_add (pre_expr e
, pre_expr v
, basic_block pred
)
556 expr_pred_trans_t
*slot
;
557 expr_pred_trans_t new_pair
= XNEW (struct expr_pred_trans_d
);
559 new_pair
->pred
= pred
;
561 new_pair
->hashcode
= iterative_hash_hashval_t (pre_expr_d::hash (e
),
564 slot
= phi_translate_table
.find_slot_with_hash (new_pair
,
565 new_pair
->hashcode
, INSERT
);
571 /* Add expression E to the expression set of value id V. */
574 add_to_value (unsigned int v
, pre_expr e
)
578 gcc_checking_assert (get_expr_value_id (e
) == v
);
580 if (v
>= value_expressions
.length ())
582 value_expressions
.safe_grow_cleared (v
+ 1);
585 set
= value_expressions
[v
];
588 set
= BITMAP_ALLOC (&grand_bitmap_obstack
);
589 value_expressions
[v
] = set
;
592 bitmap_set_bit (set
, get_or_alloc_expression_id (e
));
595 /* Create a new bitmap set and return it. */
598 bitmap_set_new (void)
600 bitmap_set_t ret
= (bitmap_set_t
) pool_alloc (bitmap_set_pool
);
601 bitmap_initialize (&ret
->expressions
, &grand_bitmap_obstack
);
602 bitmap_initialize (&ret
->values
, &grand_bitmap_obstack
);
606 /* Return the value id for a PRE expression EXPR. */
609 get_expr_value_id (pre_expr expr
)
615 id
= get_constant_value_id (PRE_EXPR_CONSTANT (expr
));
618 id
= VN_INFO (PRE_EXPR_NAME (expr
))->value_id
;
621 id
= PRE_EXPR_NARY (expr
)->value_id
;
624 id
= PRE_EXPR_REFERENCE (expr
)->value_id
;
629 /* ??? We cannot assert that expr has a value-id (it can be 0), because
630 we assign value-ids only to expressions that have a result
631 in set_hashtable_value_ids. */
635 /* Return a SCCVN valnum (SSA name or constant) for the PRE value-id VAL. */
638 sccvn_valnum_from_value_id (unsigned int val
)
642 bitmap exprset
= value_expressions
[val
];
643 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
645 pre_expr vexpr
= expression_for_id (i
);
646 if (vexpr
->kind
== NAME
)
647 return VN_INFO (PRE_EXPR_NAME (vexpr
))->valnum
;
648 else if (vexpr
->kind
== CONSTANT
)
649 return PRE_EXPR_CONSTANT (vexpr
);
654 /* Remove an expression EXPR from a bitmapped set. */
657 bitmap_remove_from_set (bitmap_set_t set
, pre_expr expr
)
659 unsigned int val
= get_expr_value_id (expr
);
660 if (!value_id_constant_p (val
))
662 bitmap_clear_bit (&set
->values
, val
);
663 bitmap_clear_bit (&set
->expressions
, get_expression_id (expr
));
668 bitmap_insert_into_set_1 (bitmap_set_t set
, pre_expr expr
,
669 unsigned int val
, bool allow_constants
)
671 if (allow_constants
|| !value_id_constant_p (val
))
673 /* We specifically expect this and only this function to be able to
674 insert constants into a set. */
675 bitmap_set_bit (&set
->values
, val
);
676 bitmap_set_bit (&set
->expressions
, get_or_alloc_expression_id (expr
));
680 /* Insert an expression EXPR into a bitmapped set. */
683 bitmap_insert_into_set (bitmap_set_t set
, pre_expr expr
)
685 bitmap_insert_into_set_1 (set
, expr
, get_expr_value_id (expr
), false);
688 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
691 bitmap_set_copy (bitmap_set_t dest
, bitmap_set_t orig
)
693 bitmap_copy (&dest
->expressions
, &orig
->expressions
);
694 bitmap_copy (&dest
->values
, &orig
->values
);
698 /* Free memory used up by SET. */
700 bitmap_set_free (bitmap_set_t set
)
702 bitmap_clear (&set
->expressions
);
703 bitmap_clear (&set
->values
);
707 /* Generate an topological-ordered array of bitmap set SET. */
710 sorted_array_from_bitmap_set (bitmap_set_t set
)
713 bitmap_iterator bi
, bj
;
714 vec
<pre_expr
> result
;
716 /* Pre-allocate roughly enough space for the array. */
717 result
.create (bitmap_count_bits (&set
->values
));
719 FOR_EACH_VALUE_ID_IN_SET (set
, i
, bi
)
721 /* The number of expressions having a given value is usually
722 relatively small. Thus, rather than making a vector of all
723 the expressions and sorting it by value-id, we walk the values
724 and check in the reverse mapping that tells us what expressions
725 have a given value, to filter those in our set. As a result,
726 the expressions are inserted in value-id order, which means
729 If this is somehow a significant lose for some cases, we can
730 choose which set to walk based on the set size. */
731 bitmap exprset
= value_expressions
[i
];
732 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, j
, bj
)
734 if (bitmap_bit_p (&set
->expressions
, j
))
735 result
.safe_push (expression_for_id (j
));
742 /* Perform bitmapped set operation DEST &= ORIG. */
745 bitmap_set_and (bitmap_set_t dest
, bitmap_set_t orig
)
753 bitmap_initialize (&temp
, &grand_bitmap_obstack
);
755 bitmap_and_into (&dest
->values
, &orig
->values
);
756 bitmap_copy (&temp
, &dest
->expressions
);
757 EXECUTE_IF_SET_IN_BITMAP (&temp
, 0, i
, bi
)
759 pre_expr expr
= expression_for_id (i
);
760 unsigned int value_id
= get_expr_value_id (expr
);
761 if (!bitmap_bit_p (&dest
->values
, value_id
))
762 bitmap_clear_bit (&dest
->expressions
, i
);
764 bitmap_clear (&temp
);
768 /* Subtract all values and expressions contained in ORIG from DEST. */
771 bitmap_set_subtract (bitmap_set_t dest
, bitmap_set_t orig
)
773 bitmap_set_t result
= bitmap_set_new ();
777 bitmap_and_compl (&result
->expressions
, &dest
->expressions
,
780 FOR_EACH_EXPR_ID_IN_SET (result
, i
, bi
)
782 pre_expr expr
= expression_for_id (i
);
783 unsigned int value_id
= get_expr_value_id (expr
);
784 bitmap_set_bit (&result
->values
, value_id
);
790 /* Subtract all the values in bitmap set B from bitmap set A. */
793 bitmap_set_subtract_values (bitmap_set_t a
, bitmap_set_t b
)
799 bitmap_initialize (&temp
, &grand_bitmap_obstack
);
801 bitmap_copy (&temp
, &a
->expressions
);
802 EXECUTE_IF_SET_IN_BITMAP (&temp
, 0, i
, bi
)
804 pre_expr expr
= expression_for_id (i
);
805 if (bitmap_set_contains_value (b
, get_expr_value_id (expr
)))
806 bitmap_remove_from_set (a
, expr
);
808 bitmap_clear (&temp
);
812 /* Return true if bitmapped set SET contains the value VALUE_ID. */
815 bitmap_set_contains_value (bitmap_set_t set
, unsigned int value_id
)
817 if (value_id_constant_p (value_id
))
820 if (!set
|| bitmap_empty_p (&set
->expressions
))
823 return bitmap_bit_p (&set
->values
, value_id
);
827 bitmap_set_contains_expr (bitmap_set_t set
, const pre_expr expr
)
829 return bitmap_bit_p (&set
->expressions
, get_expression_id (expr
));
832 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
835 bitmap_set_replace_value (bitmap_set_t set
, unsigned int lookfor
,
842 if (value_id_constant_p (lookfor
))
845 if (!bitmap_set_contains_value (set
, lookfor
))
848 /* The number of expressions having a given value is usually
849 significantly less than the total number of expressions in SET.
850 Thus, rather than check, for each expression in SET, whether it
851 has the value LOOKFOR, we walk the reverse mapping that tells us
852 what expressions have a given value, and see if any of those
853 expressions are in our set. For large testcases, this is about
854 5-10x faster than walking the bitmap. If this is somehow a
855 significant lose for some cases, we can choose which set to walk
856 based on the set size. */
857 exprset
= value_expressions
[lookfor
];
858 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
860 if (bitmap_clear_bit (&set
->expressions
, i
))
862 bitmap_set_bit (&set
->expressions
, get_expression_id (expr
));
870 /* Return true if two bitmap sets are equal. */
873 bitmap_set_equal (bitmap_set_t a
, bitmap_set_t b
)
875 return bitmap_equal_p (&a
->values
, &b
->values
);
878 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
879 and add it otherwise. */
882 bitmap_value_replace_in_set (bitmap_set_t set
, pre_expr expr
)
884 unsigned int val
= get_expr_value_id (expr
);
886 if (bitmap_set_contains_value (set
, val
))
887 bitmap_set_replace_value (set
, val
, expr
);
889 bitmap_insert_into_set (set
, expr
);
892 /* Insert EXPR into SET if EXPR's value is not already present in
896 bitmap_value_insert_into_set (bitmap_set_t set
, pre_expr expr
)
898 unsigned int val
= get_expr_value_id (expr
);
900 gcc_checking_assert (expr
->id
== get_or_alloc_expression_id (expr
));
902 /* Constant values are always considered to be part of the set. */
903 if (value_id_constant_p (val
))
906 /* If the value membership changed, add the expression. */
907 if (bitmap_set_bit (&set
->values
, val
))
908 bitmap_set_bit (&set
->expressions
, expr
->id
);
911 /* Print out EXPR to outfile. */
914 print_pre_expr (FILE *outfile
, const pre_expr expr
)
919 print_generic_expr (outfile
, PRE_EXPR_CONSTANT (expr
), 0);
922 print_generic_expr (outfile
, PRE_EXPR_NAME (expr
), 0);
927 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
928 fprintf (outfile
, "{%s,", tree_code_name
[nary
->opcode
]);
929 for (i
= 0; i
< nary
->length
; i
++)
931 print_generic_expr (outfile
, nary
->op
[i
], 0);
932 if (i
!= (unsigned) nary
->length
- 1)
933 fprintf (outfile
, ",");
935 fprintf (outfile
, "}");
941 vn_reference_op_t vro
;
943 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
944 fprintf (outfile
, "{");
946 ref
->operands
.iterate (i
, &vro
);
949 bool closebrace
= false;
950 if (vro
->opcode
!= SSA_NAME
951 && TREE_CODE_CLASS (vro
->opcode
) != tcc_declaration
)
953 fprintf (outfile
, "%s", tree_code_name
[vro
->opcode
]);
956 fprintf (outfile
, "<");
962 print_generic_expr (outfile
, vro
->op0
, 0);
965 fprintf (outfile
, ",");
966 print_generic_expr (outfile
, vro
->op1
, 0);
970 fprintf (outfile
, ",");
971 print_generic_expr (outfile
, vro
->op2
, 0);
975 fprintf (outfile
, ">");
976 if (i
!= ref
->operands
.length () - 1)
977 fprintf (outfile
, ",");
979 fprintf (outfile
, "}");
982 fprintf (outfile
, "@");
983 print_generic_expr (outfile
, ref
->vuse
, 0);
989 void debug_pre_expr (pre_expr
);
991 /* Like print_pre_expr but always prints to stderr. */
993 debug_pre_expr (pre_expr e
)
995 print_pre_expr (stderr
, e
);
996 fprintf (stderr
, "\n");
999 /* Print out SET to OUTFILE. */
1002 print_bitmap_set (FILE *outfile
, bitmap_set_t set
,
1003 const char *setname
, int blockindex
)
1005 fprintf (outfile
, "%s[%d] := { ", setname
, blockindex
);
1012 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
1014 const pre_expr expr
= expression_for_id (i
);
1017 fprintf (outfile
, ", ");
1019 print_pre_expr (outfile
, expr
);
1021 fprintf (outfile
, " (%04d)", get_expr_value_id (expr
));
1024 fprintf (outfile
, " }\n");
1027 void debug_bitmap_set (bitmap_set_t
);
1030 debug_bitmap_set (bitmap_set_t set
)
1032 print_bitmap_set (stderr
, set
, "debug", 0);
1035 void debug_bitmap_sets_for (basic_block
);
1038 debug_bitmap_sets_for (basic_block bb
)
1040 print_bitmap_set (stderr
, AVAIL_OUT (bb
), "avail_out", bb
->index
);
1041 print_bitmap_set (stderr
, EXP_GEN (bb
), "exp_gen", bb
->index
);
1042 print_bitmap_set (stderr
, PHI_GEN (bb
), "phi_gen", bb
->index
);
1043 print_bitmap_set (stderr
, TMP_GEN (bb
), "tmp_gen", bb
->index
);
1044 print_bitmap_set (stderr
, ANTIC_IN (bb
), "antic_in", bb
->index
);
1045 if (do_partial_partial
)
1046 print_bitmap_set (stderr
, PA_IN (bb
), "pa_in", bb
->index
);
1047 print_bitmap_set (stderr
, NEW_SETS (bb
), "new_sets", bb
->index
);
1050 /* Print out the expressions that have VAL to OUTFILE. */
1053 print_value_expressions (FILE *outfile
, unsigned int val
)
1055 bitmap set
= value_expressions
[val
];
1060 sprintf (s
, "%04d", val
);
1061 x
.expressions
= *set
;
1062 print_bitmap_set (outfile
, &x
, s
, 0);
1068 debug_value_expressions (unsigned int val
)
1070 print_value_expressions (stderr
, val
);
1073 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1077 get_or_alloc_expr_for_constant (tree constant
)
1079 unsigned int result_id
;
1080 unsigned int value_id
;
1081 struct pre_expr_d expr
;
1084 expr
.kind
= CONSTANT
;
1085 PRE_EXPR_CONSTANT (&expr
) = constant
;
1086 result_id
= lookup_expression_id (&expr
);
1088 return expression_for_id (result_id
);
1090 newexpr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1091 newexpr
->kind
= CONSTANT
;
1092 PRE_EXPR_CONSTANT (newexpr
) = constant
;
1093 alloc_expression_id (newexpr
);
1094 value_id
= get_or_alloc_constant_value_id (constant
);
1095 add_to_value (value_id
, newexpr
);
1099 /* Given a value id V, find the actual tree representing the constant
1100 value if there is one, and return it. Return NULL if we can't find
1104 get_constant_for_value_id (unsigned int v
)
1106 if (value_id_constant_p (v
))
1110 bitmap exprset
= value_expressions
[v
];
1112 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
1114 pre_expr expr
= expression_for_id (i
);
1115 if (expr
->kind
== CONSTANT
)
1116 return PRE_EXPR_CONSTANT (expr
);
1122 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1123 Currently only supports constants and SSA_NAMES. */
1125 get_or_alloc_expr_for (tree t
)
1127 if (TREE_CODE (t
) == SSA_NAME
)
1128 return get_or_alloc_expr_for_name (t
);
1129 else if (is_gimple_min_invariant (t
))
1130 return get_or_alloc_expr_for_constant (t
);
1133 /* More complex expressions can result from SCCVN expression
1134 simplification that inserts values for them. As they all
1135 do not have VOPs the get handled by the nary ops struct. */
1136 vn_nary_op_t result
;
1137 unsigned int result_id
;
1138 vn_nary_op_lookup (t
, &result
);
1141 pre_expr e
= (pre_expr
) pool_alloc (pre_expr_pool
);
1143 PRE_EXPR_NARY (e
) = result
;
1144 result_id
= lookup_expression_id (e
);
1147 pool_free (pre_expr_pool
, e
);
1148 e
= expression_for_id (result_id
);
1151 alloc_expression_id (e
);
1158 /* Return the folded version of T if T, when folded, is a gimple
1159 min_invariant. Otherwise, return T. */
1162 fully_constant_expression (pre_expr e
)
1170 vn_nary_op_t nary
= PRE_EXPR_NARY (e
);
1171 switch (TREE_CODE_CLASS (nary
->opcode
))
1174 case tcc_comparison
:
1176 /* We have to go from trees to pre exprs to value ids to
1178 tree naryop0
= nary
->op
[0];
1179 tree naryop1
= nary
->op
[1];
1181 if (!is_gimple_min_invariant (naryop0
))
1183 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1184 unsigned int vrep0
= get_expr_value_id (rep0
);
1185 tree const0
= get_constant_for_value_id (vrep0
);
1187 naryop0
= fold_convert (TREE_TYPE (naryop0
), const0
);
1189 if (!is_gimple_min_invariant (naryop1
))
1191 pre_expr rep1
= get_or_alloc_expr_for (naryop1
);
1192 unsigned int vrep1
= get_expr_value_id (rep1
);
1193 tree const1
= get_constant_for_value_id (vrep1
);
1195 naryop1
= fold_convert (TREE_TYPE (naryop1
), const1
);
1197 result
= fold_binary (nary
->opcode
, nary
->type
,
1199 if (result
&& is_gimple_min_invariant (result
))
1200 return get_or_alloc_expr_for_constant (result
);
1201 /* We might have simplified the expression to a
1202 SSA_NAME for example from x_1 * 1. But we cannot
1203 insert a PHI for x_1 unconditionally as x_1 might
1204 not be available readily. */
1208 if (nary
->opcode
!= REALPART_EXPR
1209 && nary
->opcode
!= IMAGPART_EXPR
1210 && nary
->opcode
!= VIEW_CONVERT_EXPR
)
1215 /* We have to go from trees to pre exprs to value ids to
1217 tree naryop0
= nary
->op
[0];
1218 tree const0
, result
;
1219 if (is_gimple_min_invariant (naryop0
))
1223 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1224 unsigned int vrep0
= get_expr_value_id (rep0
);
1225 const0
= get_constant_for_value_id (vrep0
);
1230 tree type1
= TREE_TYPE (nary
->op
[0]);
1231 const0
= fold_convert (type1
, const0
);
1232 result
= fold_unary (nary
->opcode
, nary
->type
, const0
);
1234 if (result
&& is_gimple_min_invariant (result
))
1235 return get_or_alloc_expr_for_constant (result
);
1244 vn_reference_t ref
= PRE_EXPR_REFERENCE (e
);
1246 if ((folded
= fully_constant_vn_reference_p (ref
)))
1247 return get_or_alloc_expr_for_constant (folded
);
1256 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1257 it has the value it would have in BLOCK. Set *SAME_VALID to true
1258 in case the new vuse doesn't change the value id of the OPERANDS. */
1261 translate_vuse_through_block (vec
<vn_reference_op_s
> operands
,
1262 alias_set_type set
, tree type
, tree vuse
,
1263 basic_block phiblock
,
1264 basic_block block
, bool *same_valid
)
1266 gimple phi
= SSA_NAME_DEF_STMT (vuse
);
1273 if (gimple_bb (phi
) != phiblock
)
1276 use_oracle
= ao_ref_init_from_vn_reference (&ref
, set
, type
, operands
);
1278 /* Use the alias-oracle to find either the PHI node in this block,
1279 the first VUSE used in this block that is equivalent to vuse or
1280 the first VUSE which definition in this block kills the value. */
1281 if (gimple_code (phi
) == GIMPLE_PHI
)
1282 e
= find_edge (block
, phiblock
);
1283 else if (use_oracle
)
1284 while (!stmt_may_clobber_ref_p_1 (phi
, &ref
))
1286 vuse
= gimple_vuse (phi
);
1287 phi
= SSA_NAME_DEF_STMT (vuse
);
1288 if (gimple_bb (phi
) != phiblock
)
1290 if (gimple_code (phi
) == GIMPLE_PHI
)
1292 e
= find_edge (block
, phiblock
);
1303 bitmap visited
= NULL
;
1305 /* Try to find a vuse that dominates this phi node by skipping
1306 non-clobbering statements. */
1307 vuse
= get_continuation_for_phi (phi
, &ref
, &cnt
, &visited
, false);
1309 BITMAP_FREE (visited
);
1315 /* If we didn't find any, the value ID can't stay the same,
1316 but return the translated vuse. */
1317 *same_valid
= false;
1318 vuse
= PHI_ARG_DEF (phi
, e
->dest_idx
);
1320 /* ??? We would like to return vuse here as this is the canonical
1321 upmost vdef that this reference is associated with. But during
1322 insertion of the references into the hash tables we only ever
1323 directly insert with their direct gimple_vuse, hence returning
1324 something else would make us not find the other expression. */
1325 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1331 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1332 SET2. This is used to avoid making a set consisting of the union
1333 of PA_IN and ANTIC_IN during insert. */
1335 static inline pre_expr
1336 find_leader_in_sets (unsigned int val
, bitmap_set_t set1
, bitmap_set_t set2
)
1340 result
= bitmap_find_leader (set1
, val
);
1341 if (!result
&& set2
)
1342 result
= bitmap_find_leader (set2
, val
);
1346 /* Get the tree type for our PRE expression e. */
1349 get_expr_type (const pre_expr e
)
1354 return TREE_TYPE (PRE_EXPR_NAME (e
));
1356 return TREE_TYPE (PRE_EXPR_CONSTANT (e
));
1358 return PRE_EXPR_REFERENCE (e
)->type
;
1360 return PRE_EXPR_NARY (e
)->type
;
1365 /* Get a representative SSA_NAME for a given expression.
1366 Since all of our sub-expressions are treated as values, we require
1367 them to be SSA_NAME's for simplicity.
1368 Prior versions of GVNPRE used to use "value handles" here, so that
1369 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1370 either case, the operands are really values (IE we do not expect
1371 them to be usable without finding leaders). */
1374 get_representative_for (const pre_expr e
)
1377 unsigned int value_id
= get_expr_value_id (e
);
1382 return PRE_EXPR_NAME (e
);
1384 return PRE_EXPR_CONSTANT (e
);
1388 /* Go through all of the expressions representing this value
1389 and pick out an SSA_NAME. */
1392 bitmap exprs
= value_expressions
[value_id
];
1393 EXECUTE_IF_SET_IN_BITMAP (exprs
, 0, i
, bi
)
1395 pre_expr rep
= expression_for_id (i
);
1396 if (rep
->kind
== NAME
)
1397 return PRE_EXPR_NAME (rep
);
1398 else if (rep
->kind
== CONSTANT
)
1399 return PRE_EXPR_CONSTANT (rep
);
1405 /* If we reached here we couldn't find an SSA_NAME. This can
1406 happen when we've discovered a value that has never appeared in
1407 the program as set to an SSA_NAME, as the result of phi translation.
1409 ??? We should be able to re-use this when we insert the statement
1411 name
= make_temp_ssa_name (get_expr_type (e
), gimple_build_nop (), "pretmp");
1412 VN_INFO_GET (name
)->value_id
= value_id
;
1413 VN_INFO (name
)->valnum
= name
;
1414 /* ??? For now mark this SSA name for release by SCCVN. */
1415 VN_INFO (name
)->needs_insertion
= true;
1416 add_to_value (value_id
, get_or_alloc_expr_for_name (name
));
1417 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1419 fprintf (dump_file
, "Created SSA_NAME representative ");
1420 print_generic_expr (dump_file
, name
, 0);
1421 fprintf (dump_file
, " for expression:");
1422 print_pre_expr (dump_file
, e
);
1423 fprintf (dump_file
, "\n");
1432 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1433 basic_block pred
, basic_block phiblock
);
1435 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1436 the phis in PRED. Return NULL if we can't find a leader for each part
1437 of the translated expression. */
1440 phi_translate_1 (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1441 basic_block pred
, basic_block phiblock
)
1448 bool changed
= false;
1449 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1450 vn_nary_op_t newnary
= XALLOCAVAR (struct vn_nary_op_s
,
1451 sizeof_vn_nary_op (nary
->length
));
1452 memcpy (newnary
, nary
, sizeof_vn_nary_op (nary
->length
));
1454 for (i
= 0; i
< newnary
->length
; i
++)
1456 if (TREE_CODE (newnary
->op
[i
]) != SSA_NAME
)
1460 pre_expr leader
, result
;
1461 unsigned int op_val_id
= VN_INFO (newnary
->op
[i
])->value_id
;
1462 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1463 result
= phi_translate (leader
, set1
, set2
, pred
, phiblock
);
1464 if (result
&& result
!= leader
)
1466 tree name
= get_representative_for (result
);
1469 newnary
->op
[i
] = name
;
1474 changed
|= newnary
->op
[i
] != nary
->op
[i
];
1480 unsigned int new_val_id
;
1482 tree result
= vn_nary_op_lookup_pieces (newnary
->length
,
1487 if (result
&& is_gimple_min_invariant (result
))
1488 return get_or_alloc_expr_for_constant (result
);
1490 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1495 PRE_EXPR_NARY (expr
) = nary
;
1496 constant
= fully_constant_expression (expr
);
1497 if (constant
!= expr
)
1500 new_val_id
= nary
->value_id
;
1501 get_or_alloc_expression_id (expr
);
1505 new_val_id
= get_next_value_id ();
1506 value_expressions
.safe_grow_cleared (get_max_value_id() + 1);
1507 nary
= vn_nary_op_insert_pieces (newnary
->length
,
1511 result
, new_val_id
);
1512 PRE_EXPR_NARY (expr
) = nary
;
1513 constant
= fully_constant_expression (expr
);
1514 if (constant
!= expr
)
1516 get_or_alloc_expression_id (expr
);
1518 add_to_value (new_val_id
, expr
);
1526 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1527 vec
<vn_reference_op_s
> operands
= ref
->operands
;
1528 tree vuse
= ref
->vuse
;
1529 tree newvuse
= vuse
;
1530 vec
<vn_reference_op_s
> newoperands
= vNULL
;
1531 bool changed
= false, same_valid
= true;
1532 unsigned int i
, j
, n
;
1533 vn_reference_op_t operand
;
1534 vn_reference_t newref
;
1537 operands
.iterate (i
, &operand
); i
++, j
++)
1542 tree type
= operand
->type
;
1543 vn_reference_op_s newop
= *operand
;
1544 op
[0] = operand
->op0
;
1545 op
[1] = operand
->op1
;
1546 op
[2] = operand
->op2
;
1547 for (n
= 0; n
< 3; ++n
)
1549 unsigned int op_val_id
;
1552 if (TREE_CODE (op
[n
]) != SSA_NAME
)
1554 /* We can't possibly insert these. */
1556 && !is_gimple_min_invariant (op
[n
]))
1560 op_val_id
= VN_INFO (op
[n
])->value_id
;
1561 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1564 /* Make sure we do not recursively translate ourselves
1565 like for translating a[n_1] with the leader for
1566 n_1 being a[n_1]. */
1567 if (get_expression_id (leader
) != get_expression_id (expr
))
1569 opresult
= phi_translate (leader
, set1
, set2
,
1573 if (opresult
!= leader
)
1575 tree name
= get_representative_for (opresult
);
1578 changed
|= name
!= op
[n
];
1585 newoperands
.release ();
1588 if (!newoperands
.exists ())
1589 newoperands
= operands
.copy ();
1590 /* We may have changed from an SSA_NAME to a constant */
1591 if (newop
.opcode
== SSA_NAME
&& TREE_CODE (op
[0]) != SSA_NAME
)
1592 newop
.opcode
= TREE_CODE (op
[0]);
1597 /* If it transforms a non-constant ARRAY_REF into a constant
1598 one, adjust the constant offset. */
1599 if (newop
.opcode
== ARRAY_REF
1601 && TREE_CODE (op
[0]) == INTEGER_CST
1602 && TREE_CODE (op
[1]) == INTEGER_CST
1603 && TREE_CODE (op
[2]) == INTEGER_CST
)
1605 double_int off
= tree_to_double_int (op
[0]);
1606 off
+= -tree_to_double_int (op
[1]);
1607 off
*= tree_to_double_int (op
[2]);
1608 if (off
.fits_shwi ())
1609 newop
.off
= off
.low
;
1611 newoperands
[j
] = newop
;
1612 /* If it transforms from an SSA_NAME to an address, fold with
1613 a preceding indirect reference. */
1614 if (j
> 0 && op
[0] && TREE_CODE (op
[0]) == ADDR_EXPR
1615 && newoperands
[j
- 1].opcode
== MEM_REF
)
1616 vn_reference_fold_indirect (&newoperands
, &j
);
1618 if (i
!= operands
.length ())
1620 newoperands
.release ();
1626 newvuse
= translate_vuse_through_block (newoperands
,
1627 ref
->set
, ref
->type
,
1628 vuse
, phiblock
, pred
,
1630 if (newvuse
== NULL_TREE
)
1632 newoperands
.release ();
1637 if (changed
|| newvuse
!= vuse
)
1639 unsigned int new_val_id
;
1642 tree result
= vn_reference_lookup_pieces (newvuse
, ref
->set
,
1647 newoperands
.release ();
1649 /* We can always insert constants, so if we have a partial
1650 redundant constant load of another type try to translate it
1651 to a constant of appropriate type. */
1652 if (result
&& is_gimple_min_invariant (result
))
1655 if (!useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1657 tem
= fold_unary (VIEW_CONVERT_EXPR
, ref
->type
, result
);
1658 if (tem
&& !is_gimple_min_invariant (tem
))
1662 return get_or_alloc_expr_for_constant (tem
);
1665 /* If we'd have to convert things we would need to validate
1666 if we can insert the translated expression. So fail
1667 here for now - we cannot insert an alias with a different
1668 type in the VN tables either, as that would assert. */
1670 && !useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1672 else if (!result
&& newref
1673 && !useless_type_conversion_p (ref
->type
, newref
->type
))
1675 newoperands
.release ();
1679 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1680 expr
->kind
= REFERENCE
;
1685 PRE_EXPR_REFERENCE (expr
) = newref
;
1686 constant
= fully_constant_expression (expr
);
1687 if (constant
!= expr
)
1690 new_val_id
= newref
->value_id
;
1691 get_or_alloc_expression_id (expr
);
1695 if (changed
|| !same_valid
)
1697 new_val_id
= get_next_value_id ();
1698 value_expressions
.safe_grow_cleared(get_max_value_id() + 1);
1701 new_val_id
= ref
->value_id
;
1702 newref
= vn_reference_insert_pieces (newvuse
, ref
->set
,
1705 result
, new_val_id
);
1706 newoperands
.create (0);
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 newoperands
.release ();
1722 tree name
= PRE_EXPR_NAME (expr
);
1723 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
1724 /* If the SSA name is defined by a PHI node in this block,
1726 if (gimple_code (def_stmt
) == GIMPLE_PHI
1727 && gimple_bb (def_stmt
) == phiblock
)
1729 edge e
= find_edge (pred
, gimple_bb (def_stmt
));
1730 tree def
= PHI_ARG_DEF (def_stmt
, e
->dest_idx
);
1732 /* Handle constant. */
1733 if (is_gimple_min_invariant (def
))
1734 return get_or_alloc_expr_for_constant (def
);
1736 return get_or_alloc_expr_for_name (def
);
1738 /* Otherwise return it unchanged - it will get cleaned if its
1739 value is not available in PREDs AVAIL_OUT set of expressions. */
1748 /* Wrapper around phi_translate_1 providing caching functionality. */
1751 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1752 basic_block pred
, basic_block phiblock
)
1759 /* Constants contain no values that need translation. */
1760 if (expr
->kind
== CONSTANT
)
1763 if (value_id_constant_p (get_expr_value_id (expr
)))
1766 if (expr
->kind
!= NAME
)
1768 phitrans
= phi_trans_lookup (expr
, pred
);
1774 phitrans
= phi_translate_1 (expr
, set1
, set2
, pred
, phiblock
);
1776 /* Don't add empty translations to the cache. Neither add
1777 translations of NAMEs as those are cheap to translate. */
1779 && expr
->kind
!= NAME
)
1780 phi_trans_add (expr
, phitrans
, pred
);
1786 /* For each expression in SET, translate the values through phi nodes
1787 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1788 expressions in DEST. */
1791 phi_translate_set (bitmap_set_t dest
, bitmap_set_t set
, basic_block pred
,
1792 basic_block phiblock
)
1794 vec
<pre_expr
> exprs
;
1798 if (gimple_seq_empty_p (phi_nodes (phiblock
)))
1800 bitmap_set_copy (dest
, set
);
1804 exprs
= sorted_array_from_bitmap_set (set
);
1805 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
1807 pre_expr translated
;
1808 translated
= phi_translate (expr
, set
, NULL
, pred
, phiblock
);
1812 /* We might end up with multiple expressions from SET being
1813 translated to the same value. In this case we do not want
1814 to retain the NARY or REFERENCE expression but prefer a NAME
1815 which would be the leader. */
1816 if (translated
->kind
== NAME
)
1817 bitmap_value_replace_in_set (dest
, translated
);
1819 bitmap_value_insert_into_set (dest
, translated
);
1824 /* Find the leader for a value (i.e., the name representing that
1825 value) in a given set, and return it. If STMT is non-NULL it
1826 makes sure the defining statement for the leader dominates it.
1827 Return NULL if no leader is found. */
1830 bitmap_find_leader (bitmap_set_t set
, unsigned int val
)
1832 if (value_id_constant_p (val
))
1836 bitmap exprset
= value_expressions
[val
];
1838 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
1840 pre_expr expr
= expression_for_id (i
);
1841 if (expr
->kind
== CONSTANT
)
1845 if (bitmap_set_contains_value (set
, val
))
1847 /* Rather than walk the entire bitmap of expressions, and see
1848 whether any of them has the value we are looking for, we look
1849 at the reverse mapping, which tells us the set of expressions
1850 that have a given value (IE value->expressions with that
1851 value) and see if any of those expressions are in our set.
1852 The number of expressions per value is usually significantly
1853 less than the number of expressions in the set. In fact, for
1854 large testcases, doing it this way is roughly 5-10x faster
1855 than walking the bitmap.
1856 If this is somehow a significant lose for some cases, we can
1857 choose which set to walk based on which set is smaller. */
1860 bitmap exprset
= value_expressions
[val
];
1862 EXECUTE_IF_AND_IN_BITMAP (exprset
, &set
->expressions
, 0, i
, bi
)
1863 return expression_for_id (i
);
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 /* Determine if OP is valid in SET1 U SET2, which it is when the union
1949 contains its value-id. */
1952 op_valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, tree op
)
1954 if (op
&& TREE_CODE (op
) == SSA_NAME
)
1956 unsigned int value_id
= VN_INFO (op
)->value_id
;
1957 if (!(bitmap_set_contains_value (set1
, value_id
)
1958 || (set2
&& bitmap_set_contains_value (set2
, value_id
))))
1964 /* Determine if the expression EXPR is valid in SET1 U SET2.
1965 ONLY SET2 CAN BE NULL.
1966 This means that we have a leader for each part of the expression
1967 (if it consists of values), or the expression is an SSA_NAME.
1968 For loads/calls, we also see if the vuse is killed in this block. */
1971 valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, pre_expr expr
,
1977 return bitmap_find_leader (AVAIL_OUT (block
),
1978 get_expr_value_id (expr
)) != NULL
;
1982 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1983 for (i
= 0; i
< nary
->length
; i
++)
1984 if (!op_valid_in_sets (set1
, set2
, nary
->op
[i
]))
1991 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1992 vn_reference_op_t vro
;
1995 FOR_EACH_VEC_ELT (ref
->operands
, i
, vro
)
1997 if (!op_valid_in_sets (set1
, set2
, vro
->op0
)
1998 || !op_valid_in_sets (set1
, set2
, vro
->op1
)
1999 || !op_valid_in_sets (set1
, set2
, vro
->op2
))
2009 /* Clean the set of expressions that are no longer valid in SET1 or
2010 SET2. This means expressions that are made up of values we have no
2011 leaders for in SET1 or SET2. This version is used for partial
2012 anticipation, which means it is not valid in either ANTIC_IN or
2016 dependent_clean (bitmap_set_t set1
, bitmap_set_t set2
, basic_block block
)
2018 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set1
);
2022 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
2024 if (!valid_in_sets (set1
, set2
, expr
, block
))
2025 bitmap_remove_from_set (set1
, expr
);
2030 /* Clean the set of expressions that are no longer valid in SET. This
2031 means expressions that are made up of values we have no leaders for
2035 clean (bitmap_set_t set
, basic_block block
)
2037 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set
);
2041 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
2043 if (!valid_in_sets (set
, NULL
, expr
, block
))
2044 bitmap_remove_from_set (set
, expr
);
2049 /* Clean the set of expressions that are no longer valid in SET because
2050 they are clobbered in BLOCK or because they trap and may not be executed. */
2053 prune_clobbered_mems (bitmap_set_t set
, basic_block block
)
2058 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
2060 pre_expr expr
= expression_for_id (i
);
2061 if (expr
->kind
== REFERENCE
)
2063 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2066 gimple def_stmt
= SSA_NAME_DEF_STMT (ref
->vuse
);
2067 if (!gimple_nop_p (def_stmt
)
2068 && ((gimple_bb (def_stmt
) != block
2069 && !dominated_by_p (CDI_DOMINATORS
,
2070 block
, gimple_bb (def_stmt
)))
2071 || (gimple_bb (def_stmt
) == block
2072 && value_dies_in_block_x (expr
, block
))))
2073 bitmap_remove_from_set (set
, expr
);
2076 else if (expr
->kind
== NARY
)
2078 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2079 /* If the NARY may trap make sure the block does not contain
2080 a possible exit point.
2081 ??? This is overly conservative if we translate AVAIL_OUT
2082 as the available expression might be after the exit point. */
2083 if (BB_MAY_NOTRETURN (block
)
2084 && vn_nary_may_trap (nary
))
2085 bitmap_remove_from_set (set
, expr
);
2090 static sbitmap has_abnormal_preds
;
2092 /* List of blocks that may have changed during ANTIC computation and
2093 thus need to be iterated over. */
2095 static sbitmap changed_blocks
;
2097 /* Decide whether to defer a block for a later iteration, or PHI
2098 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2099 should defer the block, and true if we processed it. */
2102 defer_or_phi_translate_block (bitmap_set_t dest
, bitmap_set_t source
,
2103 basic_block block
, basic_block phiblock
)
2105 if (!BB_VISITED (phiblock
))
2107 bitmap_set_bit (changed_blocks
, block
->index
);
2108 BB_VISITED (block
) = 0;
2109 BB_DEFERRED (block
) = 1;
2113 phi_translate_set (dest
, source
, block
, phiblock
);
2117 /* Compute the ANTIC set for BLOCK.
2119 If succs(BLOCK) > 1 then
2120 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2121 else if succs(BLOCK) == 1 then
2122 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2124 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2128 compute_antic_aux (basic_block block
, bool block_has_abnormal_pred_edge
)
2130 bool changed
= false;
2131 bitmap_set_t S
, old
, ANTIC_OUT
;
2137 old
= ANTIC_OUT
= S
= NULL
;
2138 BB_VISITED (block
) = 1;
2140 /* If any edges from predecessors are abnormal, antic_in is empty,
2142 if (block_has_abnormal_pred_edge
)
2143 goto maybe_dump_sets
;
2145 old
= ANTIC_IN (block
);
2146 ANTIC_OUT
= bitmap_set_new ();
2148 /* If the block has no successors, ANTIC_OUT is empty. */
2149 if (EDGE_COUNT (block
->succs
) == 0)
2151 /* If we have one successor, we could have some phi nodes to
2152 translate through. */
2153 else if (single_succ_p (block
))
2155 basic_block succ_bb
= single_succ (block
);
2157 /* We trade iterations of the dataflow equations for having to
2158 phi translate the maximal set, which is incredibly slow
2159 (since the maximal set often has 300+ members, even when you
2160 have a small number of blocks).
2161 Basically, we defer the computation of ANTIC for this block
2162 until we have processed it's successor, which will inevitably
2163 have a *much* smaller set of values to phi translate once
2164 clean has been run on it.
2165 The cost of doing this is that we technically perform more
2166 iterations, however, they are lower cost iterations.
2168 Timings for PRE on tramp3d-v4:
2169 without maximal set fix: 11 seconds
2170 with maximal set fix/without deferring: 26 seconds
2171 with maximal set fix/with deferring: 11 seconds
2174 if (!defer_or_phi_translate_block (ANTIC_OUT
, ANTIC_IN (succ_bb
),
2178 goto maybe_dump_sets
;
2181 /* If we have multiple successors, we take the intersection of all of
2182 them. Note that in the case of loop exit phi nodes, we may have
2183 phis to translate through. */
2186 vec
<basic_block
> worklist
;
2188 basic_block bprime
, first
= NULL
;
2190 worklist
.create (EDGE_COUNT (block
->succs
));
2191 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2194 && BB_VISITED (e
->dest
))
2196 else if (BB_VISITED (e
->dest
))
2197 worklist
.quick_push (e
->dest
);
2200 /* Of multiple successors we have to have visited one already. */
2203 bitmap_set_bit (changed_blocks
, block
->index
);
2204 BB_VISITED (block
) = 0;
2205 BB_DEFERRED (block
) = 1;
2207 worklist
.release ();
2208 goto maybe_dump_sets
;
2211 if (!gimple_seq_empty_p (phi_nodes (first
)))
2212 phi_translate_set (ANTIC_OUT
, ANTIC_IN (first
), block
, first
);
2214 bitmap_set_copy (ANTIC_OUT
, ANTIC_IN (first
));
2216 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2218 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2220 bitmap_set_t tmp
= bitmap_set_new ();
2221 phi_translate_set (tmp
, ANTIC_IN (bprime
), block
, bprime
);
2222 bitmap_set_and (ANTIC_OUT
, tmp
);
2223 bitmap_set_free (tmp
);
2226 bitmap_set_and (ANTIC_OUT
, ANTIC_IN (bprime
));
2228 worklist
.release ();
2231 /* Prune expressions that are clobbered in block and thus become
2232 invalid if translated from ANTIC_OUT to ANTIC_IN. */
2233 prune_clobbered_mems (ANTIC_OUT
, block
);
2235 /* Generate ANTIC_OUT - TMP_GEN. */
2236 S
= bitmap_set_subtract (ANTIC_OUT
, TMP_GEN (block
));
2238 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2239 ANTIC_IN (block
) = bitmap_set_subtract (EXP_GEN (block
),
2242 /* Then union in the ANTIC_OUT - TMP_GEN values,
2243 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2244 FOR_EACH_EXPR_ID_IN_SET (S
, bii
, bi
)
2245 bitmap_value_insert_into_set (ANTIC_IN (block
),
2246 expression_for_id (bii
));
2248 clean (ANTIC_IN (block
), block
);
2250 if (!bitmap_set_equal (old
, ANTIC_IN (block
)))
2253 bitmap_set_bit (changed_blocks
, block
->index
);
2254 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2255 bitmap_set_bit (changed_blocks
, e
->src
->index
);
2258 bitmap_clear_bit (changed_blocks
, block
->index
);
2261 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2263 if (!BB_DEFERRED (block
) || BB_VISITED (block
))
2266 print_bitmap_set (dump_file
, ANTIC_OUT
, "ANTIC_OUT", block
->index
);
2268 print_bitmap_set (dump_file
, ANTIC_IN (block
), "ANTIC_IN",
2272 print_bitmap_set (dump_file
, S
, "S", block
->index
);
2277 "Block %d was deferred for a future iteration.\n",
2282 bitmap_set_free (old
);
2284 bitmap_set_free (S
);
2286 bitmap_set_free (ANTIC_OUT
);
2290 /* Compute PARTIAL_ANTIC for BLOCK.
2292 If succs(BLOCK) > 1 then
2293 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2294 in ANTIC_OUT for all succ(BLOCK)
2295 else if succs(BLOCK) == 1 then
2296 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2298 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2303 compute_partial_antic_aux (basic_block block
,
2304 bool block_has_abnormal_pred_edge
)
2306 bool changed
= false;
2307 bitmap_set_t old_PA_IN
;
2308 bitmap_set_t PA_OUT
;
2311 unsigned long max_pa
= PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH
);
2313 old_PA_IN
= PA_OUT
= NULL
;
2315 /* If any edges from predecessors are abnormal, antic_in is empty,
2317 if (block_has_abnormal_pred_edge
)
2318 goto maybe_dump_sets
;
2320 /* If there are too many partially anticipatable values in the
2321 block, phi_translate_set can take an exponential time: stop
2322 before the translation starts. */
2324 && single_succ_p (block
)
2325 && bitmap_count_bits (&PA_IN (single_succ (block
))->values
) > max_pa
)
2326 goto maybe_dump_sets
;
2328 old_PA_IN
= PA_IN (block
);
2329 PA_OUT
= bitmap_set_new ();
2331 /* If the block has no successors, ANTIC_OUT is empty. */
2332 if (EDGE_COUNT (block
->succs
) == 0)
2334 /* If we have one successor, we could have some phi nodes to
2335 translate through. Note that we can't phi translate across DFS
2336 back edges in partial antic, because it uses a union operation on
2337 the successors. For recurrences like IV's, we will end up
2338 generating a new value in the set on each go around (i + 3 (VH.1)
2339 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2340 else if (single_succ_p (block
))
2342 basic_block succ
= single_succ (block
);
2343 if (!(single_succ_edge (block
)->flags
& EDGE_DFS_BACK
))
2344 phi_translate_set (PA_OUT
, PA_IN (succ
), block
, succ
);
2346 /* If we have multiple successors, we take the union of all of
2350 vec
<basic_block
> worklist
;
2354 worklist
.create (EDGE_COUNT (block
->succs
));
2355 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2357 if (e
->flags
& EDGE_DFS_BACK
)
2359 worklist
.quick_push (e
->dest
);
2361 if (worklist
.length () > 0)
2363 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2368 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime
), i
, bi
)
2369 bitmap_value_insert_into_set (PA_OUT
,
2370 expression_for_id (i
));
2371 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2373 bitmap_set_t pa_in
= bitmap_set_new ();
2374 phi_translate_set (pa_in
, PA_IN (bprime
), block
, bprime
);
2375 FOR_EACH_EXPR_ID_IN_SET (pa_in
, i
, bi
)
2376 bitmap_value_insert_into_set (PA_OUT
,
2377 expression_for_id (i
));
2378 bitmap_set_free (pa_in
);
2381 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime
), i
, bi
)
2382 bitmap_value_insert_into_set (PA_OUT
,
2383 expression_for_id (i
));
2386 worklist
.release ();
2389 /* Prune expressions that are clobbered in block and thus become
2390 invalid if translated from PA_OUT to PA_IN. */
2391 prune_clobbered_mems (PA_OUT
, block
);
2393 /* PA_IN starts with PA_OUT - TMP_GEN.
2394 Then we subtract things from ANTIC_IN. */
2395 PA_IN (block
) = bitmap_set_subtract (PA_OUT
, TMP_GEN (block
));
2397 /* For partial antic, we want to put back in the phi results, since
2398 we will properly avoid making them partially antic over backedges. */
2399 bitmap_ior_into (&PA_IN (block
)->values
, &PHI_GEN (block
)->values
);
2400 bitmap_ior_into (&PA_IN (block
)->expressions
, &PHI_GEN (block
)->expressions
);
2402 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2403 bitmap_set_subtract_values (PA_IN (block
), ANTIC_IN (block
));
2405 dependent_clean (PA_IN (block
), ANTIC_IN (block
), block
);
2407 if (!bitmap_set_equal (old_PA_IN
, PA_IN (block
)))
2410 bitmap_set_bit (changed_blocks
, block
->index
);
2411 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2412 bitmap_set_bit (changed_blocks
, e
->src
->index
);
2415 bitmap_clear_bit (changed_blocks
, block
->index
);
2418 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2421 print_bitmap_set (dump_file
, PA_OUT
, "PA_OUT", block
->index
);
2423 print_bitmap_set (dump_file
, PA_IN (block
), "PA_IN", block
->index
);
2426 bitmap_set_free (old_PA_IN
);
2428 bitmap_set_free (PA_OUT
);
2432 /* Compute ANTIC and partial ANTIC sets. */
2435 compute_antic (void)
2437 bool changed
= true;
2438 int num_iterations
= 0;
2442 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2443 We pre-build the map of blocks with incoming abnormal edges here. */
2444 has_abnormal_preds
= sbitmap_alloc (last_basic_block
);
2445 bitmap_clear (has_abnormal_preds
);
2452 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2454 e
->flags
&= ~EDGE_DFS_BACK
;
2455 if (e
->flags
& EDGE_ABNORMAL
)
2457 bitmap_set_bit (has_abnormal_preds
, block
->index
);
2462 BB_VISITED (block
) = 0;
2463 BB_DEFERRED (block
) = 0;
2465 /* While we are here, give empty ANTIC_IN sets to each block. */
2466 ANTIC_IN (block
) = bitmap_set_new ();
2467 PA_IN (block
) = bitmap_set_new ();
2470 /* At the exit block we anticipate nothing. */
2471 BB_VISITED (EXIT_BLOCK_PTR
) = 1;
2473 changed_blocks
= sbitmap_alloc (last_basic_block
+ 1);
2474 bitmap_ones (changed_blocks
);
2477 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2478 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2479 /* ??? We need to clear our PHI translation cache here as the
2480 ANTIC sets shrink and we restrict valid translations to
2481 those having operands with leaders in ANTIC. Same below
2482 for PA ANTIC computation. */
2485 for (i
= postorder_num
- 1; i
>= 0; i
--)
2487 if (bitmap_bit_p (changed_blocks
, postorder
[i
]))
2489 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2490 changed
|= compute_antic_aux (block
,
2491 bitmap_bit_p (has_abnormal_preds
,
2495 /* Theoretically possible, but *highly* unlikely. */
2496 gcc_checking_assert (num_iterations
< 500);
2499 statistics_histogram_event (cfun
, "compute_antic iterations",
2502 if (do_partial_partial
)
2504 bitmap_ones (changed_blocks
);
2505 mark_dfs_back_edges ();
2510 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2511 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2514 for (i
= postorder_num
- 1 ; i
>= 0; i
--)
2516 if (bitmap_bit_p (changed_blocks
, postorder
[i
]))
2518 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2520 |= compute_partial_antic_aux (block
,
2521 bitmap_bit_p (has_abnormal_preds
,
2525 /* Theoretically possible, but *highly* unlikely. */
2526 gcc_checking_assert (num_iterations
< 500);
2528 statistics_histogram_event (cfun
, "compute_partial_antic iterations",
2531 sbitmap_free (has_abnormal_preds
);
2532 sbitmap_free (changed_blocks
);
2536 /* Inserted expressions are placed onto this worklist, which is used
2537 for performing quick dead code elimination of insertions we made
2538 that didn't turn out to be necessary. */
2539 static bitmap inserted_exprs
;
2541 /* The actual worker for create_component_ref_by_pieces. */
2544 create_component_ref_by_pieces_1 (basic_block block
, vn_reference_t ref
,
2545 unsigned int *operand
, gimple_seq
*stmts
)
2547 vn_reference_op_t currop
= &ref
->operands
[*operand
];
2550 switch (currop
->opcode
)
2554 tree folded
, sc
= NULL_TREE
;
2555 unsigned int nargs
= 0;
2557 if (TREE_CODE (currop
->op0
) == FUNCTION_DECL
)
2560 fn
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2565 sc
= find_or_generate_expression (block
, currop
->op1
, stmts
);
2569 args
= XNEWVEC (tree
, ref
->operands
.length () - 1);
2570 while (*operand
< ref
->operands
.length ())
2572 args
[nargs
] = create_component_ref_by_pieces_1 (block
, ref
,
2578 folded
= build_call_array (currop
->type
,
2579 (TREE_CODE (fn
) == FUNCTION_DECL
2580 ? build_fold_addr_expr (fn
) : fn
),
2584 CALL_EXPR_STATIC_CHAIN (folded
) = sc
;
2590 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2594 tree offset
= currop
->op0
;
2595 if (TREE_CODE (baseop
) == ADDR_EXPR
2596 && handled_component_p (TREE_OPERAND (baseop
, 0)))
2600 base
= get_addr_base_and_unit_offset (TREE_OPERAND (baseop
, 0),
2603 offset
= int_const_binop (PLUS_EXPR
, offset
,
2604 build_int_cst (TREE_TYPE (offset
),
2606 baseop
= build_fold_addr_expr (base
);
2608 return fold_build2 (MEM_REF
, currop
->type
, baseop
, offset
);
2611 case TARGET_MEM_REF
:
2613 tree genop0
= NULL_TREE
, genop1
= NULL_TREE
;
2614 vn_reference_op_t nextop
= &ref
->operands
[++*operand
];
2615 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2621 genop0
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2627 genop1
= find_or_generate_expression (block
, nextop
->op0
, stmts
);
2631 return build5 (TARGET_MEM_REF
, currop
->type
,
2632 baseop
, currop
->op2
, genop0
, currop
->op1
, genop1
);
2638 gcc_assert (is_gimple_min_invariant (currop
->op0
));
2644 case VIEW_CONVERT_EXPR
:
2646 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2650 return fold_build1 (currop
->opcode
, currop
->type
, genop0
);
2653 case WITH_SIZE_EXPR
:
2655 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2659 tree genop1
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2662 return fold_build2 (currop
->opcode
, currop
->type
, genop0
, genop1
);
2667 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2671 tree op1
= currop
->op0
;
2672 tree op2
= currop
->op1
;
2673 return fold_build3 (BIT_FIELD_REF
, currop
->type
, genop0
, op1
, op2
);
2676 /* For array ref vn_reference_op's, operand 1 of the array ref
2677 is op0 of the reference op and operand 3 of the array ref is
2679 case ARRAY_RANGE_REF
:
2683 tree genop1
= currop
->op0
;
2684 tree genop2
= currop
->op1
;
2685 tree genop3
= currop
->op2
;
2686 genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2690 genop1
= find_or_generate_expression (block
, genop1
, stmts
);
2695 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (genop0
));
2696 /* Drop zero minimum index if redundant. */
2697 if (integer_zerop (genop2
)
2699 || integer_zerop (TYPE_MIN_VALUE (domain_type
))))
2703 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2710 tree elmt_type
= TREE_TYPE (TREE_TYPE (genop0
));
2711 /* We can't always put a size in units of the element alignment
2712 here as the element alignment may be not visible. See
2713 PR43783. Simply drop the element size for constant
2715 if (tree_int_cst_equal (genop3
, TYPE_SIZE_UNIT (elmt_type
)))
2719 genop3
= size_binop (EXACT_DIV_EXPR
, genop3
,
2720 size_int (TYPE_ALIGN_UNIT (elmt_type
)));
2721 genop3
= find_or_generate_expression (block
, genop3
, stmts
);
2726 return build4 (currop
->opcode
, currop
->type
, genop0
, genop1
,
2733 tree genop2
= currop
->op1
;
2734 op0
= create_component_ref_by_pieces_1 (block
, ref
, operand
, stmts
);
2737 /* op1 should be a FIELD_DECL, which are represented by themselves. */
2741 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2745 return fold_build3 (COMPONENT_REF
, TREE_TYPE (op1
), op0
, op1
, genop2
);
2750 genop
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2771 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2772 COMPONENT_REF or MEM_REF or ARRAY_REF portion, because we'd end up with
2773 trying to rename aggregates into ssa form directly, which is a no no.
2775 Thus, this routine doesn't create temporaries, it just builds a
2776 single access expression for the array, calling
2777 find_or_generate_expression to build the innermost pieces.
2779 This function is a subroutine of create_expression_by_pieces, and
2780 should not be called on it's own unless you really know what you
2784 create_component_ref_by_pieces (basic_block block
, vn_reference_t ref
,
2787 unsigned int op
= 0;
2788 return create_component_ref_by_pieces_1 (block
, ref
, &op
, stmts
);
2791 /* Find a simple leader for an expression, or generate one using
2792 create_expression_by_pieces from a NARY expression for the value.
2793 BLOCK is the basic_block we are looking for leaders in.
2794 OP is the tree expression to find a leader for or generate.
2795 Returns the leader or NULL_TREE on failure. */
2798 find_or_generate_expression (basic_block block
, tree op
, gimple_seq
*stmts
)
2800 pre_expr expr
= get_or_alloc_expr_for (op
);
2801 unsigned int lookfor
= get_expr_value_id (expr
);
2802 pre_expr leader
= bitmap_find_leader (AVAIL_OUT (block
), lookfor
);
2805 if (leader
->kind
== NAME
)
2806 return PRE_EXPR_NAME (leader
);
2807 else if (leader
->kind
== CONSTANT
)
2808 return PRE_EXPR_CONSTANT (leader
);
2814 /* It must be a complex expression, so generate it recursively. Note
2815 that this is only necessary to handle gcc.dg/tree-ssa/ssa-pre28.c
2816 where the insert algorithm fails to insert a required expression. */
2817 bitmap exprset
= value_expressions
[lookfor
];
2820 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
2822 pre_expr temp
= expression_for_id (i
);
2823 /* We cannot insert random REFERENCE expressions at arbitrary
2824 places. We can insert NARYs which eventually re-materializes
2825 its operand values. */
2826 if (temp
->kind
== NARY
)
2827 return create_expression_by_pieces (block
, temp
, stmts
,
2828 get_expr_type (expr
));
2835 #define NECESSARY GF_PLF_1
2837 /* Create an expression in pieces, so that we can handle very complex
2838 expressions that may be ANTIC, but not necessary GIMPLE.
2839 BLOCK is the basic block the expression will be inserted into,
2840 EXPR is the expression to insert (in value form)
2841 STMTS is a statement list to append the necessary insertions into.
2843 This function will die if we hit some value that shouldn't be
2844 ANTIC but is (IE there is no leader for it, or its components).
2845 The function returns NULL_TREE in case a different antic expression
2846 has to be inserted first.
2847 This function may also generate expressions that are themselves
2848 partially or fully redundant. Those that are will be either made
2849 fully redundant during the next iteration of insert (for partially
2850 redundant ones), or eliminated by eliminate (for fully redundant
2854 create_expression_by_pieces (basic_block block
, pre_expr expr
,
2855 gimple_seq
*stmts
, tree type
)
2859 gimple_seq forced_stmts
= NULL
;
2860 unsigned int value_id
;
2861 gimple_stmt_iterator gsi
;
2862 tree exprtype
= type
? type
: get_expr_type (expr
);
2868 /* We may hit the NAME/CONSTANT case if we have to convert types
2869 that value numbering saw through. */
2871 folded
= PRE_EXPR_NAME (expr
);
2874 folded
= PRE_EXPR_CONSTANT (expr
);
2878 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2879 folded
= create_component_ref_by_pieces (block
, ref
, stmts
);
2886 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2887 tree
*genop
= XALLOCAVEC (tree
, nary
->length
);
2889 for (i
= 0; i
< nary
->length
; ++i
)
2891 genop
[i
] = find_or_generate_expression (block
, nary
->op
[i
], stmts
);
2894 /* Ensure genop[] is properly typed for POINTER_PLUS_EXPR. It
2895 may have conversions stripped. */
2896 if (nary
->opcode
== POINTER_PLUS_EXPR
)
2899 genop
[i
] = fold_convert (nary
->type
, genop
[i
]);
2901 genop
[i
] = convert_to_ptrofftype (genop
[i
]);
2904 genop
[i
] = fold_convert (TREE_TYPE (nary
->op
[i
]), genop
[i
]);
2906 if (nary
->opcode
== CONSTRUCTOR
)
2908 vec
<constructor_elt
, va_gc
> *elts
= NULL
;
2909 for (i
= 0; i
< nary
->length
; ++i
)
2910 CONSTRUCTOR_APPEND_ELT (elts
, NULL_TREE
, genop
[i
]);
2911 folded
= build_constructor (nary
->type
, elts
);
2915 switch (nary
->length
)
2918 folded
= fold_build1 (nary
->opcode
, nary
->type
,
2922 folded
= fold_build2 (nary
->opcode
, nary
->type
,
2923 genop
[0], genop
[1]);
2926 folded
= fold_build3 (nary
->opcode
, nary
->type
,
2927 genop
[0], genop
[1], genop
[2]);
2939 if (!useless_type_conversion_p (exprtype
, TREE_TYPE (folded
)))
2940 folded
= fold_convert (exprtype
, folded
);
2942 /* Force the generated expression to be a sequence of GIMPLE
2944 We have to call unshare_expr because force_gimple_operand may
2945 modify the tree we pass to it. */
2946 folded
= force_gimple_operand (unshare_expr (folded
), &forced_stmts
,
2949 /* If we have any intermediate expressions to the value sets, add them
2950 to the value sets and chain them in the instruction stream. */
2953 gsi
= gsi_start (forced_stmts
);
2954 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
2956 gimple stmt
= gsi_stmt (gsi
);
2957 tree forcedname
= gimple_get_lhs (stmt
);
2960 if (TREE_CODE (forcedname
) == SSA_NAME
)
2962 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (forcedname
));
2963 VN_INFO_GET (forcedname
)->valnum
= forcedname
;
2964 VN_INFO (forcedname
)->value_id
= get_next_value_id ();
2965 nameexpr
= get_or_alloc_expr_for_name (forcedname
);
2966 add_to_value (VN_INFO (forcedname
)->value_id
, nameexpr
);
2967 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
2968 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
2971 gimple_seq_add_seq (stmts
, forced_stmts
);
2974 name
= make_temp_ssa_name (exprtype
, NULL
, "pretmp");
2975 newstmt
= gimple_build_assign (name
, folded
);
2976 gimple_set_plf (newstmt
, NECESSARY
, false);
2978 gimple_seq_add_stmt (stmts
, newstmt
);
2979 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (name
));
2981 /* Fold the last statement. */
2982 gsi
= gsi_last (*stmts
);
2983 if (fold_stmt_inplace (&gsi
))
2984 update_stmt (gsi_stmt (gsi
));
2986 /* Add a value number to the temporary.
2987 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
2988 we are creating the expression by pieces, and this particular piece of
2989 the expression may have been represented. There is no harm in replacing
2991 value_id
= get_expr_value_id (expr
);
2992 VN_INFO_GET (name
)->value_id
= value_id
;
2993 VN_INFO (name
)->valnum
= sccvn_valnum_from_value_id (value_id
);
2994 if (VN_INFO (name
)->valnum
== NULL_TREE
)
2995 VN_INFO (name
)->valnum
= name
;
2996 gcc_assert (VN_INFO (name
)->valnum
!= NULL_TREE
);
2997 nameexpr
= get_or_alloc_expr_for_name (name
);
2998 add_to_value (value_id
, nameexpr
);
2999 if (NEW_SETS (block
))
3000 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3001 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3003 pre_stats
.insertions
++;
3004 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3006 fprintf (dump_file
, "Inserted ");
3007 print_gimple_stmt (dump_file
, newstmt
, 0, 0);
3008 fprintf (dump_file
, " in predecessor %d\n", block
->index
);
3015 /* Returns true if we want to inhibit the insertions of PHI nodes
3016 for the given EXPR for basic block BB (a member of a loop).
3017 We want to do this, when we fear that the induction variable we
3018 create might inhibit vectorization. */
3021 inhibit_phi_insertion (basic_block bb
, pre_expr expr
)
3023 vn_reference_t vr
= PRE_EXPR_REFERENCE (expr
);
3024 vec
<vn_reference_op_s
> ops
= vr
->operands
;
3025 vn_reference_op_t op
;
3028 /* If we aren't going to vectorize we don't inhibit anything. */
3029 if (!flag_tree_loop_vectorize
)
3032 /* Otherwise we inhibit the insertion when the address of the
3033 memory reference is a simple induction variable. In other
3034 cases the vectorizer won't do anything anyway (either it's
3035 loop invariant or a complicated expression). */
3036 FOR_EACH_VEC_ELT (ops
, i
, op
)
3041 /* Calls are not a problem. */
3045 case ARRAY_RANGE_REF
:
3046 if (TREE_CODE (op
->op0
) != SSA_NAME
)
3051 basic_block defbb
= gimple_bb (SSA_NAME_DEF_STMT (op
->op0
));
3053 /* Default defs are loop invariant. */
3056 /* Defined outside this loop, also loop invariant. */
3057 if (!flow_bb_inside_loop_p (bb
->loop_father
, defbb
))
3059 /* If it's a simple induction variable inhibit insertion,
3060 the vectorizer might be interested in this one. */
3061 if (simple_iv (bb
->loop_father
, bb
->loop_father
,
3062 op
->op0
, &iv
, true))
3064 /* No simple IV, vectorizer can't do anything, hence no
3065 reason to inhibit the transformation for this operand. */
3075 /* Insert the to-be-made-available values of expression EXPRNUM for each
3076 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3077 merge the result with a phi node, given the same value number as
3078 NODE. Return true if we have inserted new stuff. */
3081 insert_into_preds_of_block (basic_block block
, unsigned int exprnum
,
3082 vec
<pre_expr
> avail
)
3084 pre_expr expr
= expression_for_id (exprnum
);
3086 unsigned int val
= get_expr_value_id (expr
);
3088 bool insertions
= false;
3093 tree type
= get_expr_type (expr
);
3097 /* Make sure we aren't creating an induction variable. */
3098 if (bb_loop_depth (block
) > 0 && EDGE_COUNT (block
->preds
) == 2)
3100 bool firstinsideloop
= false;
3101 bool secondinsideloop
= false;
3102 firstinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3103 EDGE_PRED (block
, 0)->src
);
3104 secondinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3105 EDGE_PRED (block
, 1)->src
);
3106 /* Induction variables only have one edge inside the loop. */
3107 if ((firstinsideloop
^ secondinsideloop
)
3108 && (expr
->kind
!= REFERENCE
3109 || inhibit_phi_insertion (block
, expr
)))
3111 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3112 fprintf (dump_file
, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3117 /* Make the necessary insertions. */
3118 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3120 gimple_seq stmts
= NULL
;
3123 eprime
= avail
[pred
->dest_idx
];
3125 if (eprime
->kind
!= NAME
&& eprime
->kind
!= CONSTANT
)
3127 builtexpr
= create_expression_by_pieces (bprime
, eprime
,
3129 gcc_assert (!(pred
->flags
& EDGE_ABNORMAL
));
3130 gsi_insert_seq_on_edge (pred
, stmts
);
3133 /* We cannot insert a PHI node if we failed to insert
3138 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_name (builtexpr
);
3141 else if (eprime
->kind
== CONSTANT
)
3143 /* Constants may not have the right type, fold_convert
3144 should give us back a constant with the right type. */
3145 tree constant
= PRE_EXPR_CONSTANT (eprime
);
3146 if (!useless_type_conversion_p (type
, TREE_TYPE (constant
)))
3148 tree builtexpr
= fold_convert (type
, constant
);
3149 if (!is_gimple_min_invariant (builtexpr
))
3151 tree forcedexpr
= force_gimple_operand (builtexpr
,
3154 if (!is_gimple_min_invariant (forcedexpr
))
3156 if (forcedexpr
!= builtexpr
)
3158 VN_INFO_GET (forcedexpr
)->valnum
= PRE_EXPR_CONSTANT (eprime
);
3159 VN_INFO (forcedexpr
)->value_id
= get_expr_value_id (eprime
);
3163 gimple_stmt_iterator gsi
;
3164 gsi
= gsi_start (stmts
);
3165 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3167 gimple stmt
= gsi_stmt (gsi
);
3168 tree lhs
= gimple_get_lhs (stmt
);
3169 if (TREE_CODE (lhs
) == SSA_NAME
)
3170 bitmap_set_bit (inserted_exprs
,
3171 SSA_NAME_VERSION (lhs
));
3172 gimple_set_plf (stmt
, NECESSARY
, false);
3174 gsi_insert_seq_on_edge (pred
, stmts
);
3176 avail
[pred
->dest_idx
]
3177 = get_or_alloc_expr_for_name (forcedexpr
);
3181 avail
[pred
->dest_idx
]
3182 = get_or_alloc_expr_for_constant (builtexpr
);
3185 else if (eprime
->kind
== NAME
)
3187 /* We may have to do a conversion because our value
3188 numbering can look through types in certain cases, but
3189 our IL requires all operands of a phi node have the same
3191 tree name
= PRE_EXPR_NAME (eprime
);
3192 if (!useless_type_conversion_p (type
, TREE_TYPE (name
)))
3196 builtexpr
= fold_convert (type
, name
);
3197 forcedexpr
= force_gimple_operand (builtexpr
,
3201 if (forcedexpr
!= name
)
3203 VN_INFO_GET (forcedexpr
)->valnum
= VN_INFO (name
)->valnum
;
3204 VN_INFO (forcedexpr
)->value_id
= VN_INFO (name
)->value_id
;
3209 gimple_stmt_iterator gsi
;
3210 gsi
= gsi_start (stmts
);
3211 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3213 gimple stmt
= gsi_stmt (gsi
);
3214 tree lhs
= gimple_get_lhs (stmt
);
3215 if (TREE_CODE (lhs
) == SSA_NAME
)
3216 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (lhs
));
3217 gimple_set_plf (stmt
, NECESSARY
, false);
3219 gsi_insert_seq_on_edge (pred
, stmts
);
3221 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_name (forcedexpr
);
3225 /* If we didn't want a phi node, and we made insertions, we still have
3226 inserted new stuff, and thus return true. If we didn't want a phi node,
3227 and didn't make insertions, we haven't added anything new, so return
3229 if (nophi
&& insertions
)
3231 else if (nophi
&& !insertions
)
3234 /* Now build a phi for the new variable. */
3235 temp
= make_temp_ssa_name (type
, NULL
, "prephitmp");
3236 phi
= create_phi_node (temp
, block
);
3238 gimple_set_plf (phi
, NECESSARY
, false);
3239 VN_INFO_GET (temp
)->value_id
= val
;
3240 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3241 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3242 VN_INFO (temp
)->valnum
= temp
;
3243 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3244 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3246 pre_expr ae
= avail
[pred
->dest_idx
];
3247 gcc_assert (get_expr_type (ae
) == type
3248 || useless_type_conversion_p (type
, get_expr_type (ae
)));
3249 if (ae
->kind
== CONSTANT
)
3250 add_phi_arg (phi
, unshare_expr (PRE_EXPR_CONSTANT (ae
)),
3251 pred
, UNKNOWN_LOCATION
);
3253 add_phi_arg (phi
, PRE_EXPR_NAME (ae
), pred
, UNKNOWN_LOCATION
);
3256 newphi
= get_or_alloc_expr_for_name (temp
);
3257 add_to_value (val
, newphi
);
3259 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3260 this insertion, since we test for the existence of this value in PHI_GEN
3261 before proceeding with the partial redundancy checks in insert_aux.
3263 The value may exist in AVAIL_OUT, in particular, it could be represented
3264 by the expression we are trying to eliminate, in which case we want the
3265 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3268 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3269 this block, because if it did, it would have existed in our dominator's
3270 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3273 bitmap_insert_into_set (PHI_GEN (block
), newphi
);
3274 bitmap_value_replace_in_set (AVAIL_OUT (block
),
3276 bitmap_insert_into_set (NEW_SETS (block
),
3279 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3281 fprintf (dump_file
, "Created phi ");
3282 print_gimple_stmt (dump_file
, phi
, 0, 0);
3283 fprintf (dump_file
, " in block %d\n", block
->index
);
3291 /* Perform insertion of partially redundant values.
3292 For BLOCK, do the following:
3293 1. Propagate the NEW_SETS of the dominator into the current block.
3294 If the block has multiple predecessors,
3295 2a. Iterate over the ANTIC expressions for the block to see if
3296 any of them are partially redundant.
3297 2b. If so, insert them into the necessary predecessors to make
3298 the expression fully redundant.
3299 2c. Insert a new PHI merging the values of the predecessors.
3300 2d. Insert the new PHI, and the new expressions, into the
3302 3. Recursively call ourselves on the dominator children of BLOCK.
3304 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3305 do_regular_insertion and do_partial_insertion.
3310 do_regular_insertion (basic_block block
, basic_block dom
)
3312 bool new_stuff
= false;
3313 vec
<pre_expr
> exprs
;
3315 vec
<pre_expr
> avail
= vNULL
;
3318 exprs
= sorted_array_from_bitmap_set (ANTIC_IN (block
));
3319 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3321 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3323 if (expr
->kind
== NARY
3324 || expr
->kind
== REFERENCE
)
3327 bool by_some
= false;
3328 bool cant_insert
= false;
3329 bool all_same
= true;
3330 pre_expr first_s
= NULL
;
3333 pre_expr eprime
= NULL
;
3335 pre_expr edoubleprime
= NULL
;
3336 bool do_insertion
= false;
3338 val
= get_expr_value_id (expr
);
3339 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3341 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3343 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3345 fprintf (dump_file
, "Found fully redundant value: ");
3346 print_pre_expr (dump_file
, expr
);
3347 fprintf (dump_file
, "\n");
3352 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3354 unsigned int vprime
;
3356 /* We should never run insertion for the exit block
3357 and so not come across fake pred edges. */
3358 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3360 eprime
= phi_translate (expr
, ANTIC_IN (block
), NULL
,
3363 /* eprime will generally only be NULL if the
3364 value of the expression, translated
3365 through the PHI for this predecessor, is
3366 undefined. If that is the case, we can't
3367 make the expression fully redundant,
3368 because its value is undefined along a
3369 predecessor path. We can thus break out
3370 early because it doesn't matter what the
3371 rest of the results are. */
3374 avail
[pred
->dest_idx
] = NULL
;
3379 eprime
= fully_constant_expression (eprime
);
3380 vprime
= get_expr_value_id (eprime
);
3381 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3383 if (edoubleprime
== NULL
)
3385 avail
[pred
->dest_idx
] = eprime
;
3390 avail
[pred
->dest_idx
] = edoubleprime
;
3392 /* We want to perform insertions to remove a redundancy on
3393 a path in the CFG we want to optimize for speed. */
3394 if (optimize_edge_for_speed_p (pred
))
3395 do_insertion
= true;
3396 if (first_s
== NULL
)
3397 first_s
= edoubleprime
;
3398 else if (!pre_expr_d::equal (first_s
, edoubleprime
))
3402 /* If we can insert it, it's not the same value
3403 already existing along every predecessor, and
3404 it's defined by some predecessor, it is
3405 partially redundant. */
3406 if (!cant_insert
&& !all_same
&& by_some
)
3410 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3412 fprintf (dump_file
, "Skipping partial redundancy for "
3414 print_pre_expr (dump_file
, expr
);
3415 fprintf (dump_file
, " (%04d), no redundancy on to be "
3416 "optimized for speed edge\n", val
);
3419 else if (dbg_cnt (treepre_insert
))
3421 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3423 fprintf (dump_file
, "Found partial redundancy for "
3425 print_pre_expr (dump_file
, expr
);
3426 fprintf (dump_file
, " (%04d)\n",
3427 get_expr_value_id (expr
));
3429 if (insert_into_preds_of_block (block
,
3430 get_expression_id (expr
),
3435 /* If all edges produce the same value and that value is
3436 an invariant, then the PHI has the same value on all
3437 edges. Note this. */
3438 else if (!cant_insert
&& all_same
)
3440 gcc_assert (edoubleprime
->kind
== CONSTANT
3441 || edoubleprime
->kind
== NAME
);
3443 tree temp
= make_temp_ssa_name (get_expr_type (expr
),
3445 gimple assign
= gimple_build_assign (temp
,
3446 edoubleprime
->kind
== CONSTANT
? PRE_EXPR_CONSTANT (edoubleprime
) : PRE_EXPR_NAME (edoubleprime
));
3447 gimple_stmt_iterator gsi
= gsi_after_labels (block
);
3448 gsi_insert_before (&gsi
, assign
, GSI_NEW_STMT
);
3450 gimple_set_plf (assign
, NECESSARY
, false);
3451 VN_INFO_GET (temp
)->value_id
= val
;
3452 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3453 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3454 VN_INFO (temp
)->valnum
= temp
;
3455 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3456 pre_expr newe
= get_or_alloc_expr_for_name (temp
);
3457 add_to_value (val
, newe
);
3458 bitmap_value_replace_in_set (AVAIL_OUT (block
), newe
);
3459 bitmap_insert_into_set (NEW_SETS (block
), newe
);
3470 /* Perform insertion for partially anticipatable expressions. There
3471 is only one case we will perform insertion for these. This case is
3472 if the expression is partially anticipatable, and fully available.
3473 In this case, we know that putting it earlier will enable us to
3474 remove the later computation. */
3478 do_partial_partial_insertion (basic_block block
, basic_block dom
)
3480 bool new_stuff
= false;
3481 vec
<pre_expr
> exprs
;
3483 vec
<pre_expr
> avail
= vNULL
;
3486 exprs
= sorted_array_from_bitmap_set (PA_IN (block
));
3487 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3489 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3491 if (expr
->kind
== NARY
3492 || expr
->kind
== REFERENCE
)
3496 bool cant_insert
= false;
3499 pre_expr eprime
= NULL
;
3502 val
= get_expr_value_id (expr
);
3503 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3505 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3508 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3510 unsigned int vprime
;
3511 pre_expr edoubleprime
;
3513 /* We should never run insertion for the exit block
3514 and so not come across fake pred edges. */
3515 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3517 eprime
= phi_translate (expr
, ANTIC_IN (block
),
3521 /* eprime will generally only be NULL if the
3522 value of the expression, translated
3523 through the PHI for this predecessor, is
3524 undefined. If that is the case, we can't
3525 make the expression fully redundant,
3526 because its value is undefined along a
3527 predecessor path. We can thus break out
3528 early because it doesn't matter what the
3529 rest of the results are. */
3532 avail
[pred
->dest_idx
] = NULL
;
3537 eprime
= fully_constant_expression (eprime
);
3538 vprime
= get_expr_value_id (eprime
);
3539 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
), vprime
);
3540 avail
[pred
->dest_idx
] = edoubleprime
;
3541 if (edoubleprime
== NULL
)
3548 /* If we can insert it, it's not the same value
3549 already existing along every predecessor, and
3550 it's defined by some predecessor, it is
3551 partially redundant. */
3552 if (!cant_insert
&& by_all
)
3555 bool do_insertion
= false;
3557 /* Insert only if we can remove a later expression on a path
3558 that we want to optimize for speed.
3559 The phi node that we will be inserting in BLOCK is not free,
3560 and inserting it for the sake of !optimize_for_speed successor
3561 may cause regressions on the speed path. */
3562 FOR_EACH_EDGE (succ
, ei
, block
->succs
)
3564 if (bitmap_set_contains_value (PA_IN (succ
->dest
), val
)
3565 || bitmap_set_contains_value (ANTIC_IN (succ
->dest
), val
))
3567 if (optimize_edge_for_speed_p (succ
))
3568 do_insertion
= true;
3574 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3576 fprintf (dump_file
, "Skipping partial partial redundancy "
3578 print_pre_expr (dump_file
, expr
);
3579 fprintf (dump_file
, " (%04d), not (partially) anticipated "
3580 "on any to be optimized for speed edges\n", val
);
3583 else if (dbg_cnt (treepre_insert
))
3585 pre_stats
.pa_insert
++;
3586 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3588 fprintf (dump_file
, "Found partial partial redundancy "
3590 print_pre_expr (dump_file
, expr
);
3591 fprintf (dump_file
, " (%04d)\n",
3592 get_expr_value_id (expr
));
3594 if (insert_into_preds_of_block (block
,
3595 get_expression_id (expr
),
3609 insert_aux (basic_block block
)
3612 bool new_stuff
= false;
3617 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3622 bitmap_set_t newset
= NEW_SETS (dom
);
3625 /* Note that we need to value_replace both NEW_SETS, and
3626 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3627 represented by some non-simple expression here that we want
3628 to replace it with. */
3629 FOR_EACH_EXPR_ID_IN_SET (newset
, i
, bi
)
3631 pre_expr expr
= expression_for_id (i
);
3632 bitmap_value_replace_in_set (NEW_SETS (block
), expr
);
3633 bitmap_value_replace_in_set (AVAIL_OUT (block
), expr
);
3636 if (!single_pred_p (block
))
3638 new_stuff
|= do_regular_insertion (block
, dom
);
3639 if (do_partial_partial
)
3640 new_stuff
|= do_partial_partial_insertion (block
, dom
);
3644 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3646 son
= next_dom_son (CDI_DOMINATORS
, son
))
3648 new_stuff
|= insert_aux (son
);
3654 /* Perform insertion of partially redundant values. */
3659 bool new_stuff
= true;
3661 int num_iterations
= 0;
3664 NEW_SETS (bb
) = bitmap_set_new ();
3669 if (dump_file
&& dump_flags
& TDF_DETAILS
)
3670 fprintf (dump_file
, "Starting insert iteration %d\n", num_iterations
);
3671 new_stuff
= insert_aux (ENTRY_BLOCK_PTR
);
3673 /* Clear the NEW sets before the next iteration. We have already
3674 fully propagated its contents. */
3677 bitmap_set_free (NEW_SETS (bb
));
3679 statistics_histogram_event (cfun
, "insert iterations", num_iterations
);
3683 /* Compute the AVAIL set for all basic blocks.
3685 This function performs value numbering of the statements in each basic
3686 block. The AVAIL sets are built from information we glean while doing
3687 this value numbering, since the AVAIL sets contain only one entry per
3690 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3691 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3694 compute_avail (void)
3697 basic_block block
, son
;
3698 basic_block
*worklist
;
3702 /* We pretend that default definitions are defined in the entry block.
3703 This includes function arguments and the static chain decl. */
3704 for (i
= 1; i
< num_ssa_names
; ++i
)
3706 tree name
= ssa_name (i
);
3709 || !SSA_NAME_IS_DEFAULT_DEF (name
)
3710 || has_zero_uses (name
)
3711 || virtual_operand_p (name
))
3714 e
= get_or_alloc_expr_for_name (name
);
3715 add_to_value (get_expr_value_id (e
), e
);
3716 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR
), e
);
3717 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR
), e
);
3720 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3722 print_bitmap_set (dump_file
, TMP_GEN (ENTRY_BLOCK_PTR
),
3723 "tmp_gen", ENTRY_BLOCK
);
3724 print_bitmap_set (dump_file
, AVAIL_OUT (ENTRY_BLOCK_PTR
),
3725 "avail_out", ENTRY_BLOCK
);
3728 /* Allocate the worklist. */
3729 worklist
= XNEWVEC (basic_block
, n_basic_blocks
);
3731 /* Seed the algorithm by putting the dominator children of the entry
3732 block on the worklist. */
3733 for (son
= first_dom_son (CDI_DOMINATORS
, ENTRY_BLOCK_PTR
);
3735 son
= next_dom_son (CDI_DOMINATORS
, son
))
3736 worklist
[sp
++] = son
;
3738 /* Loop until the worklist is empty. */
3741 gimple_stmt_iterator gsi
;
3745 /* Pick a block from the worklist. */
3746 block
= worklist
[--sp
];
3748 /* Initially, the set of available values in BLOCK is that of
3749 its immediate dominator. */
3750 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3752 bitmap_set_copy (AVAIL_OUT (block
), AVAIL_OUT (dom
));
3754 /* Generate values for PHI nodes. */
3755 for (gsi
= gsi_start_phis (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3757 tree result
= gimple_phi_result (gsi_stmt (gsi
));
3759 /* We have no need for virtual phis, as they don't represent
3760 actual computations. */
3761 if (virtual_operand_p (result
))
3764 pre_expr e
= get_or_alloc_expr_for_name (result
);
3765 add_to_value (get_expr_value_id (e
), e
);
3766 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3767 bitmap_insert_into_set (PHI_GEN (block
), e
);
3770 BB_MAY_NOTRETURN (block
) = 0;
3772 /* Now compute value numbers and populate value sets with all
3773 the expressions computed in BLOCK. */
3774 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3779 stmt
= gsi_stmt (gsi
);
3781 /* Cache whether the basic-block has any non-visible side-effect
3783 If this isn't a call or it is the last stmt in the
3784 basic-block then the CFG represents things correctly. */
3785 if (is_gimple_call (stmt
) && !stmt_ends_bb_p (stmt
))
3787 /* Non-looping const functions always return normally.
3788 Otherwise the call might not return or have side-effects
3789 that forbids hoisting possibly trapping expressions
3791 int flags
= gimple_call_flags (stmt
);
3792 if (!(flags
& ECF_CONST
)
3793 || (flags
& ECF_LOOPING_CONST_OR_PURE
))
3794 BB_MAY_NOTRETURN (block
) = 1;
3797 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
3799 pre_expr e
= get_or_alloc_expr_for_name (op
);
3801 add_to_value (get_expr_value_id (e
), e
);
3802 bitmap_insert_into_set (TMP_GEN (block
), e
);
3803 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3806 if (gimple_has_side_effects (stmt
)
3807 || stmt_could_throw_p (stmt
)
3808 || is_gimple_debug (stmt
))
3811 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3813 if (ssa_undefined_value_p (op
))
3815 pre_expr e
= get_or_alloc_expr_for_name (op
);
3816 bitmap_value_insert_into_set (EXP_GEN (block
), e
);
3819 switch (gimple_code (stmt
))
3827 pre_expr result
= NULL
;
3828 vec
<vn_reference_op_s
> ops
= vNULL
;
3830 /* We can value number only calls to real functions. */
3831 if (gimple_call_internal_p (stmt
))
3834 copy_reference_ops_from_call (stmt
, &ops
);
3835 vn_reference_lookup_pieces (gimple_vuse (stmt
), 0,
3836 gimple_expr_type (stmt
),
3837 ops
, &ref
, VN_NOWALK
);
3842 /* If the value of the call is not invalidated in
3843 this block until it is computed, add the expression
3845 if (!gimple_vuse (stmt
)
3847 (SSA_NAME_DEF_STMT (gimple_vuse (stmt
))) == GIMPLE_PHI
3848 || gimple_bb (SSA_NAME_DEF_STMT
3849 (gimple_vuse (stmt
))) != block
)
3851 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3852 result
->kind
= REFERENCE
;
3854 PRE_EXPR_REFERENCE (result
) = ref
;
3856 get_or_alloc_expression_id (result
);
3857 add_to_value (get_expr_value_id (result
), result
);
3858 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3865 pre_expr result
= NULL
;
3866 switch (vn_get_stmt_kind (stmt
))
3870 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3873 /* COND_EXPR and VEC_COND_EXPR are awkward in
3874 that they contain an embedded complex expression.
3875 Don't even try to shove those through PRE. */
3876 if (code
== COND_EXPR
3877 || code
== VEC_COND_EXPR
)
3880 vn_nary_op_lookup_stmt (stmt
, &nary
);
3884 /* If the NARY traps and there was a preceding
3885 point in the block that might not return avoid
3886 adding the nary to EXP_GEN. */
3887 if (BB_MAY_NOTRETURN (block
)
3888 && vn_nary_may_trap (nary
))
3891 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3892 result
->kind
= NARY
;
3894 PRE_EXPR_NARY (result
) = nary
;
3901 vn_reference_lookup (gimple_assign_rhs1 (stmt
),
3907 /* If the value of the reference is not invalidated in
3908 this block until it is computed, add the expression
3910 if (gimple_vuse (stmt
))
3914 def_stmt
= SSA_NAME_DEF_STMT (gimple_vuse (stmt
));
3915 while (!gimple_nop_p (def_stmt
)
3916 && gimple_code (def_stmt
) != GIMPLE_PHI
3917 && gimple_bb (def_stmt
) == block
)
3919 if (stmt_may_clobber_ref_p
3920 (def_stmt
, gimple_assign_rhs1 (stmt
)))
3926 = SSA_NAME_DEF_STMT (gimple_vuse (def_stmt
));
3932 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3933 result
->kind
= REFERENCE
;
3935 PRE_EXPR_REFERENCE (result
) = ref
;
3943 get_or_alloc_expression_id (result
);
3944 add_to_value (get_expr_value_id (result
), result
);
3945 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3953 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3955 print_bitmap_set (dump_file
, EXP_GEN (block
),
3956 "exp_gen", block
->index
);
3957 print_bitmap_set (dump_file
, PHI_GEN (block
),
3958 "phi_gen", block
->index
);
3959 print_bitmap_set (dump_file
, TMP_GEN (block
),
3960 "tmp_gen", block
->index
);
3961 print_bitmap_set (dump_file
, AVAIL_OUT (block
),
3962 "avail_out", block
->index
);
3965 /* Put the dominator children of BLOCK on the worklist of blocks
3966 to compute available sets for. */
3967 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3969 son
= next_dom_son (CDI_DOMINATORS
, son
))
3970 worklist
[sp
++] = son
;
3977 /* Local state for the eliminate domwalk. */
3978 static vec
<gimple
> el_to_remove
;
3979 static vec
<gimple
> el_to_update
;
3980 static unsigned int el_todo
;
3981 static vec
<tree
> el_avail
;
3982 static vec
<tree
> el_avail_stack
;
3984 /* Return a leader for OP that is available at the current point of the
3985 eliminate domwalk. */
3988 eliminate_avail (tree op
)
3990 tree valnum
= VN_INFO (op
)->valnum
;
3991 if (TREE_CODE (valnum
) == SSA_NAME
)
3993 if (SSA_NAME_IS_DEFAULT_DEF (valnum
))
3995 if (el_avail
.length () > SSA_NAME_VERSION (valnum
))
3996 return el_avail
[SSA_NAME_VERSION (valnum
)];
3998 else if (is_gimple_min_invariant (valnum
))
4003 /* At the current point of the eliminate domwalk make OP available. */
4006 eliminate_push_avail (tree op
)
4008 tree valnum
= VN_INFO (op
)->valnum
;
4009 if (TREE_CODE (valnum
) == SSA_NAME
)
4011 if (el_avail
.length () <= SSA_NAME_VERSION (valnum
))
4012 el_avail
.safe_grow_cleared (SSA_NAME_VERSION (valnum
) + 1);
4013 el_avail
[SSA_NAME_VERSION (valnum
)] = op
;
4014 el_avail_stack
.safe_push (op
);
4018 /* Insert the expression recorded by SCCVN for VAL at *GSI. Returns
4019 the leader for the expression if insertion was successful. */
4022 eliminate_insert (gimple_stmt_iterator
*gsi
, tree val
)
4024 tree expr
= vn_get_expr_for (val
);
4025 if (!CONVERT_EXPR_P (expr
)
4026 && TREE_CODE (expr
) != VIEW_CONVERT_EXPR
)
4029 tree op
= TREE_OPERAND (expr
, 0);
4030 tree leader
= TREE_CODE (op
) == SSA_NAME
? eliminate_avail (op
) : op
;
4034 tree res
= make_temp_ssa_name (TREE_TYPE (val
), NULL
, "pretmp");
4035 gimple tem
= gimple_build_assign (res
,
4036 fold_build1 (TREE_CODE (expr
),
4037 TREE_TYPE (expr
), leader
));
4038 gsi_insert_before (gsi
, tem
, GSI_SAME_STMT
);
4039 VN_INFO_GET (res
)->valnum
= val
;
4041 if (TREE_CODE (leader
) == SSA_NAME
)
4042 gimple_set_plf (SSA_NAME_DEF_STMT (leader
), NECESSARY
, true);
4044 pre_stats
.insertions
++;
4045 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4047 fprintf (dump_file
, "Inserted ");
4048 print_gimple_stmt (dump_file
, tem
, 0, 0);
4054 class eliminate_dom_walker
: public dom_walker
4057 eliminate_dom_walker (cdi_direction direction
) : dom_walker (direction
) {}
4059 virtual void before_dom_children (basic_block
);
4060 virtual void after_dom_children (basic_block
);
4063 /* Perform elimination for the basic-block B during the domwalk. */
4066 eliminate_dom_walker::before_dom_children (basic_block b
)
4068 gimple_stmt_iterator gsi
;
4072 el_avail_stack
.safe_push (NULL_TREE
);
4074 for (gsi
= gsi_start_phis (b
); !gsi_end_p (gsi
);)
4076 gimple stmt
, phi
= gsi_stmt (gsi
);
4077 tree sprime
= NULL_TREE
, res
= PHI_RESULT (phi
);
4078 gimple_stmt_iterator gsi2
;
4080 /* We want to perform redundant PHI elimination. Do so by
4081 replacing the PHI with a single copy if possible.
4082 Do not touch inserted, single-argument or virtual PHIs. */
4083 if (gimple_phi_num_args (phi
) == 1
4084 || virtual_operand_p (res
))
4090 sprime
= eliminate_avail (res
);
4094 eliminate_push_avail (res
);
4098 else if (is_gimple_min_invariant (sprime
))
4100 if (!useless_type_conversion_p (TREE_TYPE (res
),
4101 TREE_TYPE (sprime
)))
4102 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4105 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4107 fprintf (dump_file
, "Replaced redundant PHI node defining ");
4108 print_generic_expr (dump_file
, res
, 0);
4109 fprintf (dump_file
, " with ");
4110 print_generic_expr (dump_file
, sprime
, 0);
4111 fprintf (dump_file
, "\n");
4114 remove_phi_node (&gsi
, false);
4117 && !bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (res
))
4118 && TREE_CODE (sprime
) == SSA_NAME
)
4119 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
), NECESSARY
, true);
4121 if (!useless_type_conversion_p (TREE_TYPE (res
), TREE_TYPE (sprime
)))
4122 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4123 stmt
= gimple_build_assign (res
, sprime
);
4124 SSA_NAME_DEF_STMT (res
) = stmt
;
4125 gimple_set_plf (stmt
, NECESSARY
, gimple_plf (phi
, NECESSARY
));
4127 gsi2
= gsi_after_labels (b
);
4128 gsi_insert_before (&gsi2
, stmt
, GSI_NEW_STMT
);
4129 /* Queue the copy for eventual removal. */
4130 el_to_remove
.safe_push (stmt
);
4131 /* If we inserted this PHI node ourself, it's not an elimination. */
4133 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (res
)))
4136 pre_stats
.eliminations
++;
4139 for (gsi
= gsi_start_bb (b
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4141 tree lhs
= NULL_TREE
;
4142 tree rhs
= NULL_TREE
;
4144 stmt
= gsi_stmt (gsi
);
4146 if (gimple_has_lhs (stmt
))
4147 lhs
= gimple_get_lhs (stmt
);
4149 if (gimple_assign_single_p (stmt
))
4150 rhs
= gimple_assign_rhs1 (stmt
);
4152 /* Lookup the RHS of the expression, see if we have an
4153 available computation for it. If so, replace the RHS with
4154 the available computation. */
4155 if (gimple_has_lhs (stmt
)
4156 && TREE_CODE (lhs
) == SSA_NAME
4157 && !gimple_has_volatile_ops (stmt
))
4160 gimple orig_stmt
= stmt
;
4162 sprime
= eliminate_avail (lhs
);
4163 /* If there is no usable leader mark lhs as leader for its value. */
4165 eliminate_push_avail (lhs
);
4167 /* See PR43491. Do not replace a global register variable when
4168 it is a the RHS of an assignment. Do replace local register
4169 variables since gcc does not guarantee a local variable will
4170 be allocated in register.
4171 Do not perform copy propagation or undo constant propagation. */
4172 if (gimple_assign_single_p (stmt
)
4173 && (TREE_CODE (rhs
) == SSA_NAME
4174 || is_gimple_min_invariant (rhs
)
4175 || (TREE_CODE (rhs
) == VAR_DECL
4176 && is_global_var (rhs
)
4177 && DECL_HARD_REGISTER (rhs
))))
4182 /* If there is no existing usable leader but SCCVN thinks
4183 it has an expression it wants to use as replacement,
4185 tree val
= VN_INFO (lhs
)->valnum
;
4187 && TREE_CODE (val
) == SSA_NAME
4188 && VN_INFO (val
)->needs_insertion
4189 && VN_INFO (val
)->expr
!= NULL_TREE
4190 && (sprime
= eliminate_insert (&gsi
, val
)) != NULL_TREE
)
4191 eliminate_push_avail (sprime
);
4193 else if (is_gimple_min_invariant (sprime
))
4195 /* If there is no existing leader but SCCVN knows this
4196 value is constant, use that constant. */
4197 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
4198 TREE_TYPE (sprime
)))
4199 sprime
= fold_convert (TREE_TYPE (lhs
), sprime
);
4201 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4203 fprintf (dump_file
, "Replaced ");
4204 print_gimple_expr (dump_file
, stmt
, 0, 0);
4205 fprintf (dump_file
, " with ");
4206 print_generic_expr (dump_file
, sprime
, 0);
4207 fprintf (dump_file
, " in ");
4208 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4210 pre_stats
.eliminations
++;
4211 propagate_tree_value_into_stmt (&gsi
, sprime
);
4212 stmt
= gsi_stmt (gsi
);
4215 /* If we removed EH side-effects from the statement, clean
4216 its EH information. */
4217 if (maybe_clean_or_replace_eh_stmt (orig_stmt
, stmt
))
4219 bitmap_set_bit (need_eh_cleanup
,
4220 gimple_bb (stmt
)->index
);
4221 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4222 fprintf (dump_file
, " Removed EH side-effects.\n");
4229 && (rhs
== NULL_TREE
4230 || TREE_CODE (rhs
) != SSA_NAME
4231 || may_propagate_copy (rhs
, sprime
)))
4233 bool can_make_abnormal_goto
4234 = is_gimple_call (stmt
)
4235 && stmt_can_make_abnormal_goto (stmt
);
4237 gcc_assert (sprime
!= rhs
);
4239 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4241 fprintf (dump_file
, "Replaced ");
4242 print_gimple_expr (dump_file
, stmt
, 0, 0);
4243 fprintf (dump_file
, " with ");
4244 print_generic_expr (dump_file
, sprime
, 0);
4245 fprintf (dump_file
, " in ");
4246 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4249 if (TREE_CODE (sprime
) == SSA_NAME
)
4250 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4252 /* We need to make sure the new and old types actually match,
4253 which may require adding a simple cast, which fold_convert
4255 if ((!rhs
|| TREE_CODE (rhs
) != SSA_NAME
)
4256 && !useless_type_conversion_p (gimple_expr_type (stmt
),
4257 TREE_TYPE (sprime
)))
4258 sprime
= fold_convert (gimple_expr_type (stmt
), sprime
);
4260 pre_stats
.eliminations
++;
4261 propagate_tree_value_into_stmt (&gsi
, sprime
);
4262 stmt
= gsi_stmt (gsi
);
4265 /* If we removed EH side-effects from the statement, clean
4266 its EH information. */
4267 if (maybe_clean_or_replace_eh_stmt (orig_stmt
, stmt
))
4269 bitmap_set_bit (need_eh_cleanup
,
4270 gimple_bb (stmt
)->index
);
4271 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4272 fprintf (dump_file
, " Removed EH side-effects.\n");
4275 /* Likewise for AB side-effects. */
4276 if (can_make_abnormal_goto
4277 && !stmt_can_make_abnormal_goto (stmt
))
4279 bitmap_set_bit (need_ab_cleanup
,
4280 gimple_bb (stmt
)->index
);
4281 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4282 fprintf (dump_file
, " Removed AB side-effects.\n");
4286 /* If the statement is a scalar store, see if the expression
4287 has the same value number as its rhs. If so, the store is
4289 else if (gimple_assign_single_p (stmt
)
4290 && !gimple_has_volatile_ops (stmt
)
4291 && !is_gimple_reg (gimple_assign_lhs (stmt
))
4292 && (TREE_CODE (rhs
) == SSA_NAME
4293 || is_gimple_min_invariant (rhs
)))
4296 val
= vn_reference_lookup (gimple_assign_lhs (stmt
),
4297 gimple_vuse (stmt
), VN_WALK
, NULL
);
4298 if (TREE_CODE (rhs
) == SSA_NAME
)
4299 rhs
= VN_INFO (rhs
)->valnum
;
4301 && operand_equal_p (val
, rhs
, 0))
4303 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4305 fprintf (dump_file
, "Deleted redundant store ");
4306 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4309 /* Queue stmt for removal. */
4310 el_to_remove
.safe_push (stmt
);
4313 /* Visit COND_EXPRs and fold the comparison with the
4314 available value-numbers. */
4315 else if (gimple_code (stmt
) == GIMPLE_COND
)
4317 tree op0
= gimple_cond_lhs (stmt
);
4318 tree op1
= gimple_cond_rhs (stmt
);
4321 if (TREE_CODE (op0
) == SSA_NAME
)
4322 op0
= VN_INFO (op0
)->valnum
;
4323 if (TREE_CODE (op1
) == SSA_NAME
)
4324 op1
= VN_INFO (op1
)->valnum
;
4325 result
= fold_binary (gimple_cond_code (stmt
), boolean_type_node
,
4327 if (result
&& TREE_CODE (result
) == INTEGER_CST
)
4329 if (integer_zerop (result
))
4330 gimple_cond_make_false (stmt
);
4332 gimple_cond_make_true (stmt
);
4334 el_todo
= TODO_cleanup_cfg
;
4337 /* Visit indirect calls and turn them into direct calls if
4339 if (is_gimple_call (stmt
))
4341 tree orig_fn
= gimple_call_fn (stmt
);
4345 if (TREE_CODE (orig_fn
) == SSA_NAME
)
4346 fn
= VN_INFO (orig_fn
)->valnum
;
4347 else if (TREE_CODE (orig_fn
) == OBJ_TYPE_REF
4348 && TREE_CODE (OBJ_TYPE_REF_EXPR (orig_fn
)) == SSA_NAME
)
4350 fn
= VN_INFO (OBJ_TYPE_REF_EXPR (orig_fn
))->valnum
;
4351 if (!gimple_call_addr_fndecl (fn
))
4353 fn
= ipa_intraprocedural_devirtualization (stmt
);
4355 fn
= build_fold_addr_expr (fn
);
4360 if (gimple_call_addr_fndecl (fn
) != NULL_TREE
4361 && useless_type_conversion_p (TREE_TYPE (orig_fn
),
4364 bool can_make_abnormal_goto
4365 = stmt_can_make_abnormal_goto (stmt
);
4366 bool was_noreturn
= gimple_call_noreturn_p (stmt
);
4368 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4370 fprintf (dump_file
, "Replacing call target with ");
4371 print_generic_expr (dump_file
, fn
, 0);
4372 fprintf (dump_file
, " in ");
4373 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4376 gimple_call_set_fn (stmt
, fn
);
4377 el_to_update
.safe_push (stmt
);
4379 /* When changing a call into a noreturn call, cfg cleanup
4380 is needed to fix up the noreturn call. */
4381 if (!was_noreturn
&& gimple_call_noreturn_p (stmt
))
4382 el_todo
|= TODO_cleanup_cfg
;
4384 /* If we removed EH side-effects from the statement, clean
4385 its EH information. */
4386 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4388 bitmap_set_bit (need_eh_cleanup
,
4389 gimple_bb (stmt
)->index
);
4390 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4391 fprintf (dump_file
, " Removed EH side-effects.\n");
4394 /* Likewise for AB side-effects. */
4395 if (can_make_abnormal_goto
4396 && !stmt_can_make_abnormal_goto (stmt
))
4398 bitmap_set_bit (need_ab_cleanup
,
4399 gimple_bb (stmt
)->index
);
4400 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4401 fprintf (dump_file
, " Removed AB side-effects.\n");
4404 /* Changing an indirect call to a direct call may
4405 have exposed different semantics. This may
4406 require an SSA update. */
4407 el_todo
|= TODO_update_ssa_only_virtuals
;
4413 /* Make no longer available leaders no longer available. */
4416 eliminate_dom_walker::after_dom_children (basic_block
)
4419 while ((entry
= el_avail_stack
.pop ()) != NULL_TREE
)
4420 el_avail
[SSA_NAME_VERSION (VN_INFO (entry
)->valnum
)] = NULL_TREE
;
4423 /* Eliminate fully redundant computations. */
4428 gimple_stmt_iterator gsi
;
4432 need_eh_cleanup
= BITMAP_ALLOC (NULL
);
4433 need_ab_cleanup
= BITMAP_ALLOC (NULL
);
4435 el_to_remove
.create (0);
4436 el_to_update
.create (0);
4438 el_avail
.create (0);
4439 el_avail_stack
.create (0);
4441 eliminate_dom_walker (CDI_DOMINATORS
).walk (cfun
->cfg
->x_entry_block_ptr
);
4443 el_avail
.release ();
4444 el_avail_stack
.release ();
4446 /* We cannot remove stmts during BB walk, especially not release SSA
4447 names there as this confuses the VN machinery. The stmts ending
4448 up in el_to_remove are either stores or simple copies. */
4449 FOR_EACH_VEC_ELT (el_to_remove
, i
, stmt
)
4451 tree lhs
= gimple_assign_lhs (stmt
);
4452 tree rhs
= gimple_assign_rhs1 (stmt
);
4453 use_operand_p use_p
;
4456 /* If there is a single use only, propagate the equivalency
4457 instead of keeping the copy. */
4458 if (TREE_CODE (lhs
) == SSA_NAME
4459 && TREE_CODE (rhs
) == SSA_NAME
4460 && single_imm_use (lhs
, &use_p
, &use_stmt
)
4461 && may_propagate_copy (USE_FROM_PTR (use_p
), rhs
))
4463 SET_USE (use_p
, rhs
);
4464 update_stmt (use_stmt
);
4466 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (lhs
))
4467 && TREE_CODE (rhs
) == SSA_NAME
)
4468 gimple_set_plf (SSA_NAME_DEF_STMT (rhs
), NECESSARY
, true);
4471 /* If this is a store or a now unused copy, remove it. */
4472 if (TREE_CODE (lhs
) != SSA_NAME
4473 || has_zero_uses (lhs
))
4475 basic_block bb
= gimple_bb (stmt
);
4476 gsi
= gsi_for_stmt (stmt
);
4477 unlink_stmt_vdef (stmt
);
4478 if (gsi_remove (&gsi
, true))
4479 bitmap_set_bit (need_eh_cleanup
, bb
->index
);
4481 && TREE_CODE (lhs
) == SSA_NAME
)
4482 bitmap_clear_bit (inserted_exprs
, SSA_NAME_VERSION (lhs
));
4483 release_defs (stmt
);
4486 el_to_remove
.release ();
4488 /* We cannot update call statements with virtual operands during
4489 SSA walk. This might remove them which in turn makes our
4490 VN lattice invalid. */
4491 FOR_EACH_VEC_ELT (el_to_update
, i
, stmt
)
4493 el_to_update
.release ();
4498 /* Perform CFG cleanups made necessary by elimination. */
4501 fini_eliminate (void)
4503 bool do_eh_cleanup
= !bitmap_empty_p (need_eh_cleanup
);
4504 bool do_ab_cleanup
= !bitmap_empty_p (need_ab_cleanup
);
4507 gimple_purge_all_dead_eh_edges (need_eh_cleanup
);
4510 gimple_purge_all_dead_abnormal_call_edges (need_ab_cleanup
);
4512 BITMAP_FREE (need_eh_cleanup
);
4513 BITMAP_FREE (need_ab_cleanup
);
4515 if (do_eh_cleanup
|| do_ab_cleanup
)
4516 return TODO_cleanup_cfg
;
4520 /* Borrow a bit of tree-ssa-dce.c for the moment.
4521 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4522 this may be a bit faster, and we may want critical edges kept split. */
4524 /* If OP's defining statement has not already been determined to be necessary,
4525 mark that statement necessary. Return the stmt, if it is newly
4528 static inline gimple
4529 mark_operand_necessary (tree op
)
4535 if (TREE_CODE (op
) != SSA_NAME
)
4538 stmt
= SSA_NAME_DEF_STMT (op
);
4541 if (gimple_plf (stmt
, NECESSARY
)
4542 || gimple_nop_p (stmt
))
4545 gimple_set_plf (stmt
, NECESSARY
, true);
4549 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4550 to insert PHI nodes sometimes, and because value numbering of casts isn't
4551 perfect, we sometimes end up inserting dead code. This simple DCE-like
4552 pass removes any insertions we made that weren't actually used. */
4555 remove_dead_inserted_code (void)
4562 worklist
= BITMAP_ALLOC (NULL
);
4563 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs
, 0, i
, bi
)
4565 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4566 if (gimple_plf (t
, NECESSARY
))
4567 bitmap_set_bit (worklist
, i
);
4569 while (!bitmap_empty_p (worklist
))
4571 i
= bitmap_first_set_bit (worklist
);
4572 bitmap_clear_bit (worklist
, i
);
4573 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4575 /* PHI nodes are somewhat special in that each PHI alternative has
4576 data and control dependencies. All the statements feeding the
4577 PHI node's arguments are always necessary. */
4578 if (gimple_code (t
) == GIMPLE_PHI
)
4582 for (k
= 0; k
< gimple_phi_num_args (t
); k
++)
4584 tree arg
= PHI_ARG_DEF (t
, k
);
4585 if (TREE_CODE (arg
) == SSA_NAME
)
4587 gimple n
= mark_operand_necessary (arg
);
4589 bitmap_set_bit (worklist
, SSA_NAME_VERSION (arg
));
4595 /* Propagate through the operands. Examine all the USE, VUSE and
4596 VDEF operands in this statement. Mark all the statements
4597 which feed this statement's uses as necessary. */
4601 /* The operands of VDEF expressions are also needed as they
4602 represent potential definitions that may reach this
4603 statement (VDEF operands allow us to follow def-def
4606 FOR_EACH_SSA_TREE_OPERAND (use
, t
, iter
, SSA_OP_ALL_USES
)
4608 gimple n
= mark_operand_necessary (use
);
4610 bitmap_set_bit (worklist
, SSA_NAME_VERSION (use
));
4615 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs
, 0, i
, bi
)
4617 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4618 if (!gimple_plf (t
, NECESSARY
))
4620 gimple_stmt_iterator gsi
;
4622 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4624 fprintf (dump_file
, "Removing unnecessary insertion:");
4625 print_gimple_stmt (dump_file
, t
, 0, 0);
4628 gsi
= gsi_for_stmt (t
);
4629 if (gimple_code (t
) == GIMPLE_PHI
)
4630 remove_phi_node (&gsi
, true);
4633 gsi_remove (&gsi
, true);
4638 BITMAP_FREE (worklist
);
4642 /* Initialize data structures used by PRE. */
4649 next_expression_id
= 1;
4650 expressions
.create (0);
4651 expressions
.safe_push (NULL
);
4652 value_expressions
.create (get_max_value_id () + 1);
4653 value_expressions
.safe_grow_cleared (get_max_value_id() + 1);
4654 name_to_id
.create (0);
4656 inserted_exprs
= BITMAP_ALLOC (NULL
);
4658 connect_infinite_loops_to_exit ();
4659 memset (&pre_stats
, 0, sizeof (pre_stats
));
4661 postorder
= XNEWVEC (int, n_basic_blocks
);
4662 postorder_num
= inverted_post_order_compute (postorder
);
4664 alloc_aux_for_blocks (sizeof (struct bb_bitmap_sets
));
4666 calculate_dominance_info (CDI_POST_DOMINATORS
);
4667 calculate_dominance_info (CDI_DOMINATORS
);
4669 bitmap_obstack_initialize (&grand_bitmap_obstack
);
4670 phi_translate_table
.create (5110);
4671 expression_to_id
.create (num_ssa_names
* 3);
4672 bitmap_set_pool
= create_alloc_pool ("Bitmap sets",
4673 sizeof (struct bitmap_set
), 30);
4674 pre_expr_pool
= create_alloc_pool ("pre_expr nodes",
4675 sizeof (struct pre_expr_d
), 30);
4678 EXP_GEN (bb
) = bitmap_set_new ();
4679 PHI_GEN (bb
) = bitmap_set_new ();
4680 TMP_GEN (bb
) = bitmap_set_new ();
4681 AVAIL_OUT (bb
) = bitmap_set_new ();
4686 /* Deallocate data structures used by PRE. */
4692 value_expressions
.release ();
4693 BITMAP_FREE (inserted_exprs
);
4694 bitmap_obstack_release (&grand_bitmap_obstack
);
4695 free_alloc_pool (bitmap_set_pool
);
4696 free_alloc_pool (pre_expr_pool
);
4697 phi_translate_table
.dispose ();
4698 expression_to_id
.dispose ();
4699 name_to_id
.release ();
4701 free_aux_for_blocks ();
4703 free_dominance_info (CDI_POST_DOMINATORS
);
4706 /* Gate and execute functions for PRE. */
4711 unsigned int todo
= 0;
4713 do_partial_partial
=
4714 flag_tree_partial_pre
&& optimize_function_for_speed_p (cfun
);
4716 /* This has to happen before SCCVN runs because
4717 loop_optimizer_init may create new phis, etc. */
4718 loop_optimizer_init (LOOPS_NORMAL
);
4720 if (!run_scc_vn (VN_WALK
))
4722 loop_optimizer_finalize ();
4729 /* Collect and value number expressions computed in each basic block. */
4732 /* Insert can get quite slow on an incredibly large number of basic
4733 blocks due to some quadratic behavior. Until this behavior is
4734 fixed, don't run it when he have an incredibly large number of
4735 bb's. If we aren't going to run insert, there is no point in
4736 computing ANTIC, either, even though it's plenty fast. */
4737 if (n_basic_blocks
< 4000)
4743 /* Make sure to remove fake edges before committing our inserts.
4744 This makes sure we don't end up with extra critical edges that
4745 we would need to split. */
4746 remove_fake_exit_edges ();
4747 gsi_commit_edge_inserts ();
4749 /* Remove all the redundant expressions. */
4750 todo
|= eliminate ();
4752 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4753 statistics_counter_event (cfun
, "PA inserted", pre_stats
.pa_insert
);
4754 statistics_counter_event (cfun
, "New PHIs", pre_stats
.phis
);
4755 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4757 clear_expression_ids ();
4758 remove_dead_inserted_code ();
4759 todo
|= TODO_verify_flow
;
4763 todo
|= fini_eliminate ();
4764 loop_optimizer_finalize ();
4766 /* TODO: tail_merge_optimize may merge all predecessors of a block, in which
4767 case we can merge the block with the remaining predecessor of the block.
4769 - call merge_blocks after each tail merge iteration
4770 - call merge_blocks after all tail merge iterations
4771 - mark TODO_cleanup_cfg when necessary
4772 - share the cfg cleanup with fini_pre. */
4773 todo
|= tail_merge_optimize (todo
);
4777 /* Tail merging invalidates the virtual SSA web, together with
4778 cfg-cleanup opportunities exposed by PRE this will wreck the
4779 SSA updating machinery. So make sure to run update-ssa
4780 manually, before eventually scheduling cfg-cleanup as part of
4782 update_ssa (TODO_update_ssa_only_virtuals
);
4790 return flag_tree_pre
!= 0;
4795 const pass_data pass_data_pre
=
4797 GIMPLE_PASS
, /* type */
4799 OPTGROUP_NONE
, /* optinfo_flags */
4800 true, /* has_gate */
4801 true, /* has_execute */
4802 TV_TREE_PRE
, /* tv_id */
4803 ( PROP_no_crit_edges
| PROP_cfg
| PROP_ssa
), /* properties_required */
4804 0, /* properties_provided */
4805 0, /* properties_destroyed */
4806 TODO_rebuild_alias
, /* todo_flags_start */
4807 TODO_verify_ssa
, /* todo_flags_finish */
4810 class pass_pre
: public gimple_opt_pass
4813 pass_pre(gcc::context
*ctxt
)
4814 : gimple_opt_pass(pass_data_pre
, ctxt
)
4817 /* opt_pass methods: */
4818 bool gate () { return gate_pre (); }
4819 unsigned int execute () { return do_pre (); }
4821 }; // class pass_pre
4826 make_pass_pre (gcc::context
*ctxt
)
4828 return new pass_pre (ctxt
);
4832 /* Gate and execute functions for FRE. */
4837 unsigned int todo
= 0;
4839 if (!run_scc_vn (VN_WALKREWRITE
))
4842 memset (&pre_stats
, 0, sizeof (pre_stats
));
4844 /* Remove all the redundant expressions. */
4845 todo
|= eliminate ();
4847 todo
|= fini_eliminate ();
4851 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4852 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4860 return flag_tree_fre
!= 0;
4865 const pass_data pass_data_fre
=
4867 GIMPLE_PASS
, /* type */
4869 OPTGROUP_NONE
, /* optinfo_flags */
4870 true, /* has_gate */
4871 true, /* has_execute */
4872 TV_TREE_FRE
, /* tv_id */
4873 ( PROP_cfg
| PROP_ssa
), /* properties_required */
4874 0, /* properties_provided */
4875 0, /* properties_destroyed */
4876 0, /* todo_flags_start */
4877 TODO_verify_ssa
, /* todo_flags_finish */
4880 class pass_fre
: public gimple_opt_pass
4883 pass_fre(gcc::context
*ctxt
)
4884 : gimple_opt_pass(pass_data_fre
, ctxt
)
4887 /* opt_pass methods: */
4888 opt_pass
* clone () { return new pass_fre (ctxt_
); }
4889 bool gate () { return gate_fre (); }
4890 unsigned int execute () { return execute_fre (); }
4892 }; // class pass_fre
4897 make_pass_fre (gcc::context
*ctxt
)
4899 return new pass_fre (ctxt
);