2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-inline.h"
32 #include "tree-flow.h"
34 #include "tree-dump.h"
38 #include "tree-iterator.h"
40 #include "alloc-pool.h"
42 #include "tree-pass.h"
45 #include "langhooks.h"
47 #include "tree-ssa-sccvn.h"
53 1. Avail sets can be shared by making an avail_find_leader that
54 walks up the dominator tree and looks in those avail sets.
55 This might affect code optimality, it's unclear right now.
56 2. Strength reduction can be performed by anticipating expressions
57 we can repair later on.
58 3. We can do back-substitution or smarter value numbering to catch
59 commutative expressions split up over multiple statements.
62 /* For ease of terminology, "expression node" in the below refers to
63 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
64 represent the actual statement containing the expressions we care about,
65 and we cache the value number by putting it in the expression. */
69 First we walk the statements to generate the AVAIL sets, the
70 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
71 generation of values/expressions by a given block. We use them
72 when computing the ANTIC sets. The AVAIL sets consist of
73 SSA_NAME's that represent values, so we know what values are
74 available in what blocks. AVAIL is a forward dataflow problem. In
75 SSA, values are never killed, so we don't need a kill set, or a
76 fixpoint iteration, in order to calculate the AVAIL sets. In
77 traditional parlance, AVAIL sets tell us the downsafety of the
80 Next, we generate the ANTIC sets. These sets represent the
81 anticipatable expressions. ANTIC is a backwards dataflow
82 problem. An expression is anticipatable in a given block if it could
83 be generated in that block. This means that if we had to perform
84 an insertion in that block, of the value of that expression, we
85 could. Calculating the ANTIC sets requires phi translation of
86 expressions, because the flow goes backwards through phis. We must
87 iterate to a fixpoint of the ANTIC sets, because we have a kill
88 set. Even in SSA form, values are not live over the entire
89 function, only from their definition point onwards. So we have to
90 remove values from the ANTIC set once we go past the definition
91 point of the leaders that make them up.
92 compute_antic/compute_antic_aux performs this computation.
94 Third, we perform insertions to make partially redundant
95 expressions fully redundant.
97 An expression is partially redundant (excluding partial
100 1. It is AVAIL in some, but not all, of the predecessors of a
102 2. It is ANTIC in all the predecessors.
104 In order to make it fully redundant, we insert the expression into
105 the predecessors where it is not available, but is ANTIC.
107 For the partial anticipation case, we only perform insertion if it
108 is partially anticipated in some block, and fully available in all
111 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
112 performs these steps.
114 Fourth, we eliminate fully redundant expressions.
115 This is a simple statement walk that replaces redundant
116 calculations with the now available values. */
118 /* Representations of value numbers:
120 Value numbers are represented by a representative SSA_NAME. We
121 will create fake SSA_NAME's in situations where we need a
122 representative but do not have one (because it is a complex
123 expression). In order to facilitate storing the value numbers in
124 bitmaps, and keep the number of wasted SSA_NAME's down, we also
125 associate a value_id with each value number, and create full blown
126 ssa_name's only where we actually need them (IE in operands of
127 existing expressions).
129 Theoretically you could replace all the value_id's with
130 SSA_NAME_VERSION, but this would allocate a large number of
131 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
132 It would also require an additional indirection at each point we
135 /* Representation of expressions on value numbers:
137 Expressions consisting of value numbers are represented the same
138 way as our VN internally represents them, with an additional
139 "pre_expr" wrapping around them in order to facilitate storing all
140 of the expressions in the same sets. */
142 /* Representation of sets:
144 The dataflow sets do not need to be sorted in any particular order
145 for the majority of their lifetime, are simply represented as two
146 bitmaps, one that keeps track of values present in the set, and one
147 that keeps track of expressions present in the set.
149 When we need them in topological order, we produce it on demand by
150 transforming the bitmap into an array and sorting it into topo
153 /* Type of expression, used to know which member of the PRE_EXPR union
164 typedef union pre_expr_union_d
169 vn_reference_t reference
;
172 typedef struct pre_expr_d
174 enum pre_expr_kind kind
;
179 #define PRE_EXPR_NAME(e) (e)->u.name
180 #define PRE_EXPR_NARY(e) (e)->u.nary
181 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
182 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
185 pre_expr_eq (const void *p1
, const void *p2
)
187 const struct pre_expr_d
*e1
= (const struct pre_expr_d
*) p1
;
188 const struct pre_expr_d
*e2
= (const struct pre_expr_d
*) p2
;
190 if (e1
->kind
!= e2
->kind
)
196 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1
),
197 PRE_EXPR_CONSTANT (e2
));
199 return PRE_EXPR_NAME (e1
) == PRE_EXPR_NAME (e2
);
201 return vn_nary_op_eq (PRE_EXPR_NARY (e1
), PRE_EXPR_NARY (e2
));
203 return vn_reference_eq (PRE_EXPR_REFERENCE (e1
),
204 PRE_EXPR_REFERENCE (e2
));
211 pre_expr_hash (const void *p1
)
213 const struct pre_expr_d
*e
= (const struct pre_expr_d
*) p1
;
217 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e
));
219 return iterative_hash_hashval_t (SSA_NAME_VERSION (PRE_EXPR_NAME (e
)), 0);
221 return PRE_EXPR_NARY (e
)->hashcode
;
223 return PRE_EXPR_REFERENCE (e
)->hashcode
;
230 /* Next global expression id number. */
231 static unsigned int next_expression_id
;
233 /* Mapping from expression to id number we can use in bitmap sets. */
234 DEF_VEC_P (pre_expr
);
235 DEF_VEC_ALLOC_P (pre_expr
, heap
);
236 static VEC(pre_expr
, heap
) *expressions
;
237 static htab_t expression_to_id
;
239 /* Allocate an expression id for EXPR. */
241 static inline unsigned int
242 alloc_expression_id (pre_expr expr
)
245 /* Make sure we won't overflow. */
246 gcc_assert (next_expression_id
+ 1 > next_expression_id
);
247 expr
->id
= next_expression_id
++;
248 VEC_safe_push (pre_expr
, heap
, expressions
, expr
);
249 slot
= htab_find_slot (expression_to_id
, expr
, INSERT
);
252 return next_expression_id
- 1;
255 /* Return the expression id for tree EXPR. */
257 static inline unsigned int
258 get_expression_id (const pre_expr expr
)
263 static inline unsigned int
264 lookup_expression_id (const pre_expr expr
)
268 slot
= htab_find_slot (expression_to_id
, expr
, NO_INSERT
);
271 return ((pre_expr
)*slot
)->id
;
274 /* Return the existing expression id for EXPR, or create one if one
275 does not exist yet. */
277 static inline unsigned int
278 get_or_alloc_expression_id (pre_expr expr
)
280 unsigned int id
= lookup_expression_id (expr
);
282 return alloc_expression_id (expr
);
283 return expr
->id
= id
;
286 /* Return the expression that has expression id ID */
288 static inline pre_expr
289 expression_for_id (unsigned int id
)
291 return VEC_index (pre_expr
, expressions
, id
);
294 /* Free the expression id field in all of our expressions,
295 and then destroy the expressions array. */
298 clear_expression_ids (void)
300 VEC_free (pre_expr
, heap
, expressions
);
303 static alloc_pool pre_expr_pool
;
305 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
308 get_or_alloc_expr_for_name (tree name
)
310 pre_expr result
= (pre_expr
) pool_alloc (pre_expr_pool
);
311 unsigned int result_id
;
315 PRE_EXPR_NAME (result
) = name
;
316 result_id
= lookup_expression_id (result
);
319 pool_free (pre_expr_pool
, result
);
320 result
= expression_for_id (result_id
);
323 get_or_alloc_expression_id (result
);
327 static bool in_fre
= false;
329 /* An unordered bitmap set. One bitmap tracks values, the other,
331 typedef struct bitmap_set
337 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
338 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
340 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
341 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
343 /* Mapping from value id to expressions with that value_id. */
344 DEF_VEC_P (bitmap_set_t
);
345 DEF_VEC_ALLOC_P (bitmap_set_t
, heap
);
346 static VEC(bitmap_set_t
, heap
) *value_expressions
;
348 /* Sets that we need to keep track of. */
349 typedef struct bb_bitmap_sets
351 /* The EXP_GEN set, which represents expressions/values generated in
353 bitmap_set_t exp_gen
;
355 /* The PHI_GEN set, which represents PHI results generated in a
357 bitmap_set_t phi_gen
;
359 /* The TMP_GEN set, which represents results/temporaries generated
360 in a basic block. IE the LHS of an expression. */
361 bitmap_set_t tmp_gen
;
363 /* The AVAIL_OUT set, which represents which values are available in
364 a given basic block. */
365 bitmap_set_t avail_out
;
367 /* The ANTIC_IN set, which represents which values are anticipatable
368 in a given basic block. */
369 bitmap_set_t antic_in
;
371 /* The PA_IN set, which represents which values are
372 partially anticipatable in a given basic block. */
375 /* The NEW_SETS set, which is used during insertion to augment the
376 AVAIL_OUT set of blocks with the new insertions performed during
377 the current iteration. */
378 bitmap_set_t new_sets
;
380 /* A cache for value_dies_in_block_x. */
383 /* True if we have visited this block during ANTIC calculation. */
384 unsigned int visited
:1;
386 /* True we have deferred processing this block during ANTIC
387 calculation until its successor is processed. */
388 unsigned int deferred
: 1;
391 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
392 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
393 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
394 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
395 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
396 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
397 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
398 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
399 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
400 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
403 /* Maximal set of values, used to initialize the ANTIC problem, which
404 is an intersection problem. */
405 static bitmap_set_t maximal_set
;
407 /* Basic block list in postorder. */
408 static int *postorder
;
410 /* This structure is used to keep track of statistics on what
411 optimization PRE was able to perform. */
414 /* The number of RHS computations eliminated by PRE. */
417 /* The number of new expressions/temporaries generated by PRE. */
420 /* The number of inserts found due to partial anticipation */
423 /* The number of new PHI nodes added by PRE. */
426 /* The number of values found constant. */
431 static bool do_partial_partial
;
432 static pre_expr
bitmap_find_leader (bitmap_set_t
, unsigned int, gimple
);
433 static void bitmap_value_insert_into_set (bitmap_set_t
, pre_expr
);
434 static void bitmap_value_replace_in_set (bitmap_set_t
, pre_expr
);
435 static void bitmap_set_copy (bitmap_set_t
, bitmap_set_t
);
436 static bool bitmap_set_contains_value (bitmap_set_t
, unsigned int);
437 static void bitmap_insert_into_set (bitmap_set_t
, pre_expr
);
438 static void bitmap_insert_into_set_1 (bitmap_set_t
, pre_expr
, bool);
439 static bitmap_set_t
bitmap_set_new (void);
440 static tree
create_expression_by_pieces (basic_block
, pre_expr
, gimple_seq
*,
442 static tree
find_or_generate_expression (basic_block
, pre_expr
, gimple_seq
*,
444 static unsigned int get_expr_value_id (pre_expr
);
446 /* We can add and remove elements and entries to and from sets
447 and hash tables, so we use alloc pools for them. */
449 static alloc_pool bitmap_set_pool
;
450 static bitmap_obstack grand_bitmap_obstack
;
452 /* To avoid adding 300 temporary variables when we only need one, we
453 only create one temporary variable, on demand, and build ssa names
454 off that. We do have to change the variable if the types don't
455 match the current variable's type. */
457 static tree storetemp
;
458 static tree prephitemp
;
460 /* Set of blocks with statements that have had its EH information
462 static bitmap need_eh_cleanup
;
464 /* Which expressions have been seen during a given phi translation. */
465 static bitmap seen_during_translate
;
467 /* The phi_translate_table caches phi translations for a given
468 expression and predecessor. */
470 static htab_t phi_translate_table
;
472 /* A three tuple {e, pred, v} used to cache phi translations in the
473 phi_translate_table. */
475 typedef struct expr_pred_trans_d
477 /* The expression. */
480 /* The predecessor block along which we translated the expression. */
483 /* The value that resulted from the translation. */
486 /* The hashcode for the expression, pred pair. This is cached for
489 } *expr_pred_trans_t
;
490 typedef const struct expr_pred_trans_d
*const_expr_pred_trans_t
;
492 /* Return the hash value for a phi translation table entry. */
495 expr_pred_trans_hash (const void *p
)
497 const_expr_pred_trans_t
const ve
= (const_expr_pred_trans_t
) p
;
501 /* Return true if two phi translation table entries are the same.
502 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
505 expr_pred_trans_eq (const void *p1
, const void *p2
)
507 const_expr_pred_trans_t
const ve1
= (const_expr_pred_trans_t
) p1
;
508 const_expr_pred_trans_t
const ve2
= (const_expr_pred_trans_t
) p2
;
509 basic_block b1
= ve1
->pred
;
510 basic_block b2
= ve2
->pred
;
512 /* If they are not translations for the same basic block, they can't
516 return pre_expr_eq (ve1
->e
, ve2
->e
);
519 /* Search in the phi translation table for the translation of
520 expression E in basic block PRED.
521 Return the translated value, if found, NULL otherwise. */
523 static inline pre_expr
524 phi_trans_lookup (pre_expr e
, basic_block pred
)
527 struct expr_pred_trans_d ept
;
531 ept
.hashcode
= iterative_hash_hashval_t (pre_expr_hash (e
), pred
->index
);
532 slot
= htab_find_slot_with_hash (phi_translate_table
, &ept
, ept
.hashcode
,
537 return ((expr_pred_trans_t
) *slot
)->v
;
541 /* Add the tuple mapping from {expression E, basic block PRED} to
542 value V, to the phi translation table. */
545 phi_trans_add (pre_expr e
, pre_expr v
, basic_block pred
)
548 expr_pred_trans_t new_pair
= XNEW (struct expr_pred_trans_d
);
550 new_pair
->pred
= pred
;
552 new_pair
->hashcode
= iterative_hash_hashval_t (pre_expr_hash (e
),
555 slot
= htab_find_slot_with_hash (phi_translate_table
, new_pair
,
556 new_pair
->hashcode
, INSERT
);
559 *slot
= (void *) new_pair
;
563 /* Add expression E to the expression set of value id V. */
566 add_to_value (unsigned int v
, pre_expr e
)
570 gcc_assert (get_expr_value_id (e
) == v
);
572 if (v
>= VEC_length (bitmap_set_t
, value_expressions
))
574 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
578 set
= VEC_index (bitmap_set_t
, value_expressions
, v
);
581 set
= bitmap_set_new ();
582 VEC_replace (bitmap_set_t
, value_expressions
, v
, set
);
585 bitmap_insert_into_set_1 (set
, e
, true);
588 /* Create a new bitmap set and return it. */
591 bitmap_set_new (void)
593 bitmap_set_t ret
= (bitmap_set_t
) pool_alloc (bitmap_set_pool
);
594 ret
->expressions
= BITMAP_ALLOC (&grand_bitmap_obstack
);
595 ret
->values
= BITMAP_ALLOC (&grand_bitmap_obstack
);
599 /* Return the value id for a PRE expression EXPR. */
602 get_expr_value_id (pre_expr expr
)
609 id
= get_constant_value_id (PRE_EXPR_CONSTANT (expr
));
612 id
= get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr
));
613 add_to_value (id
, expr
);
618 return VN_INFO (PRE_EXPR_NAME (expr
))->value_id
;
620 return PRE_EXPR_NARY (expr
)->value_id
;
622 return PRE_EXPR_REFERENCE (expr
)->value_id
;
628 /* Remove an expression EXPR from a bitmapped set. */
631 bitmap_remove_from_set (bitmap_set_t set
, pre_expr expr
)
633 unsigned int val
= get_expr_value_id (expr
);
634 if (!value_id_constant_p (val
))
636 bitmap_clear_bit (set
->values
, val
);
637 bitmap_clear_bit (set
->expressions
, get_expression_id (expr
));
642 bitmap_insert_into_set_1 (bitmap_set_t set
, pre_expr expr
,
643 bool allow_constants
)
645 unsigned int val
= get_expr_value_id (expr
);
646 if (allow_constants
|| !value_id_constant_p (val
))
648 /* We specifically expect this and only this function to be able to
649 insert constants into a set. */
650 bitmap_set_bit (set
->values
, val
);
651 bitmap_set_bit (set
->expressions
, get_or_alloc_expression_id (expr
));
655 /* Insert an expression EXPR into a bitmapped set. */
658 bitmap_insert_into_set (bitmap_set_t set
, pre_expr expr
)
660 bitmap_insert_into_set_1 (set
, expr
, false);
663 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
666 bitmap_set_copy (bitmap_set_t dest
, bitmap_set_t orig
)
668 bitmap_copy (dest
->expressions
, orig
->expressions
);
669 bitmap_copy (dest
->values
, orig
->values
);
673 /* Free memory used up by SET. */
675 bitmap_set_free (bitmap_set_t set
)
677 BITMAP_FREE (set
->expressions
);
678 BITMAP_FREE (set
->values
);
682 /* Generate an topological-ordered array of bitmap set SET. */
684 static VEC(pre_expr
, heap
) *
685 sorted_array_from_bitmap_set (bitmap_set_t set
)
688 bitmap_iterator bi
, bj
;
689 VEC(pre_expr
, heap
) *result
= NULL
;
691 FOR_EACH_VALUE_ID_IN_SET (set
, i
, bi
)
693 /* The number of expressions having a given value is usually
694 relatively small. Thus, rather than making a vector of all
695 the expressions and sorting it by value-id, we walk the values
696 and check in the reverse mapping that tells us what expressions
697 have a given value, to filter those in our set. As a result,
698 the expressions are inserted in value-id order, which means
701 If this is somehow a significant lose for some cases, we can
702 choose which set to walk based on the set size. */
703 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, i
);
704 FOR_EACH_EXPR_ID_IN_SET (exprset
, j
, bj
)
706 if (bitmap_bit_p (set
->expressions
, j
))
707 VEC_safe_push (pre_expr
, heap
, result
, expression_for_id (j
));
714 /* Perform bitmapped set operation DEST &= ORIG. */
717 bitmap_set_and (bitmap_set_t dest
, bitmap_set_t orig
)
724 bitmap temp
= BITMAP_ALLOC (&grand_bitmap_obstack
);
726 bitmap_and_into (dest
->values
, orig
->values
);
727 bitmap_copy (temp
, dest
->expressions
);
728 EXECUTE_IF_SET_IN_BITMAP (temp
, 0, i
, bi
)
730 pre_expr expr
= expression_for_id (i
);
731 unsigned int value_id
= get_expr_value_id (expr
);
732 if (!bitmap_bit_p (dest
->values
, value_id
))
733 bitmap_clear_bit (dest
->expressions
, i
);
739 /* Subtract all values and expressions contained in ORIG from DEST. */
742 bitmap_set_subtract (bitmap_set_t dest
, bitmap_set_t orig
)
744 bitmap_set_t result
= bitmap_set_new ();
748 bitmap_and_compl (result
->expressions
, dest
->expressions
,
751 FOR_EACH_EXPR_ID_IN_SET (result
, i
, bi
)
753 pre_expr expr
= expression_for_id (i
);
754 unsigned int value_id
= get_expr_value_id (expr
);
755 bitmap_set_bit (result
->values
, value_id
);
761 /* Subtract all the values in bitmap set B from bitmap set A. */
764 bitmap_set_subtract_values (bitmap_set_t a
, bitmap_set_t b
)
768 bitmap temp
= BITMAP_ALLOC (&grand_bitmap_obstack
);
770 bitmap_copy (temp
, a
->expressions
);
771 EXECUTE_IF_SET_IN_BITMAP (temp
, 0, i
, bi
)
773 pre_expr expr
= expression_for_id (i
);
774 if (bitmap_set_contains_value (b
, get_expr_value_id (expr
)))
775 bitmap_remove_from_set (a
, expr
);
781 /* Return true if bitmapped set SET contains the value VALUE_ID. */
784 bitmap_set_contains_value (bitmap_set_t set
, unsigned int value_id
)
786 if (value_id_constant_p (value_id
))
789 if (!set
|| bitmap_empty_p (set
->expressions
))
792 return bitmap_bit_p (set
->values
, value_id
);
796 bitmap_set_contains_expr (bitmap_set_t set
, const pre_expr expr
)
798 return bitmap_bit_p (set
->expressions
, get_expression_id (expr
));
801 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
804 bitmap_set_replace_value (bitmap_set_t set
, unsigned int lookfor
,
807 bitmap_set_t exprset
;
811 if (value_id_constant_p (lookfor
))
814 if (!bitmap_set_contains_value (set
, lookfor
))
817 /* The number of expressions having a given value is usually
818 significantly less than the total number of expressions in SET.
819 Thus, rather than check, for each expression in SET, whether it
820 has the value LOOKFOR, we walk the reverse mapping that tells us
821 what expressions have a given value, and see if any of those
822 expressions are in our set. For large testcases, this is about
823 5-10x faster than walking the bitmap. If this is somehow a
824 significant lose for some cases, we can choose which set to walk
825 based on the set size. */
826 exprset
= VEC_index (bitmap_set_t
, value_expressions
, lookfor
);
827 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
829 if (bitmap_bit_p (set
->expressions
, i
))
831 bitmap_clear_bit (set
->expressions
, i
);
832 bitmap_set_bit (set
->expressions
, get_expression_id (expr
));
838 /* Return true if two bitmap sets are equal. */
841 bitmap_set_equal (bitmap_set_t a
, bitmap_set_t b
)
843 return bitmap_equal_p (a
->values
, b
->values
);
846 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
847 and add it otherwise. */
850 bitmap_value_replace_in_set (bitmap_set_t set
, pre_expr expr
)
852 unsigned int val
= get_expr_value_id (expr
);
854 if (bitmap_set_contains_value (set
, val
))
855 bitmap_set_replace_value (set
, val
, expr
);
857 bitmap_insert_into_set (set
, expr
);
860 /* Insert EXPR into SET if EXPR's value is not already present in
864 bitmap_value_insert_into_set (bitmap_set_t set
, pre_expr expr
)
866 unsigned int val
= get_expr_value_id (expr
);
868 if (value_id_constant_p (val
))
871 if (!bitmap_set_contains_value (set
, val
))
872 bitmap_insert_into_set (set
, expr
);
875 /* Print out EXPR to outfile. */
878 print_pre_expr (FILE *outfile
, const pre_expr expr
)
883 print_generic_expr (outfile
, PRE_EXPR_CONSTANT (expr
), 0);
886 print_generic_expr (outfile
, PRE_EXPR_NAME (expr
), 0);
891 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
892 fprintf (outfile
, "{%s,", tree_code_name
[nary
->opcode
]);
893 for (i
= 0; i
< nary
->length
; i
++)
895 print_generic_expr (outfile
, nary
->op
[i
], 0);
896 if (i
!= (unsigned) nary
->length
- 1)
897 fprintf (outfile
, ",");
899 fprintf (outfile
, "}");
905 vn_reference_op_t vro
;
907 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
908 fprintf (outfile
, "{");
910 VEC_iterate (vn_reference_op_s
, ref
->operands
, i
, vro
);
913 bool closebrace
= false;
914 if (vro
->opcode
!= SSA_NAME
915 && TREE_CODE_CLASS (vro
->opcode
) != tcc_declaration
)
917 fprintf (outfile
, "%s", tree_code_name
[vro
->opcode
]);
920 fprintf (outfile
, "<");
926 print_generic_expr (outfile
, vro
->op0
, 0);
929 fprintf (outfile
, ",");
930 print_generic_expr (outfile
, vro
->op1
, 0);
934 fprintf (outfile
, ",");
935 print_generic_expr (outfile
, vro
->op2
, 0);
939 fprintf (outfile
, ">");
940 if (i
!= VEC_length (vn_reference_op_s
, ref
->operands
) - 1)
941 fprintf (outfile
, ",");
943 fprintf (outfile
, "}");
946 fprintf (outfile
, "@");
947 print_generic_expr (outfile
, ref
->vuse
, 0);
953 void debug_pre_expr (pre_expr
);
955 /* Like print_pre_expr but always prints to stderr. */
957 debug_pre_expr (pre_expr e
)
959 print_pre_expr (stderr
, e
);
960 fprintf (stderr
, "\n");
963 /* Print out SET to OUTFILE. */
966 print_bitmap_set (FILE *outfile
, bitmap_set_t set
,
967 const char *setname
, int blockindex
)
969 fprintf (outfile
, "%s[%d] := { ", setname
, blockindex
);
976 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
978 const pre_expr expr
= expression_for_id (i
);
981 fprintf (outfile
, ", ");
983 print_pre_expr (outfile
, expr
);
985 fprintf (outfile
, " (%04d)", get_expr_value_id (expr
));
988 fprintf (outfile
, " }\n");
991 void debug_bitmap_set (bitmap_set_t
);
994 debug_bitmap_set (bitmap_set_t set
)
996 print_bitmap_set (stderr
, set
, "debug", 0);
999 /* Print out the expressions that have VAL to OUTFILE. */
1002 print_value_expressions (FILE *outfile
, unsigned int val
)
1004 bitmap_set_t set
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1008 sprintf (s
, "%04d", val
);
1009 print_bitmap_set (outfile
, set
, s
, 0);
1015 debug_value_expressions (unsigned int val
)
1017 print_value_expressions (stderr
, val
);
1020 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1024 get_or_alloc_expr_for_constant (tree constant
)
1026 unsigned int result_id
;
1027 unsigned int value_id
;
1028 pre_expr newexpr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1029 newexpr
->kind
= CONSTANT
;
1030 PRE_EXPR_CONSTANT (newexpr
) = constant
;
1031 result_id
= lookup_expression_id (newexpr
);
1034 pool_free (pre_expr_pool
, newexpr
);
1035 newexpr
= expression_for_id (result_id
);
1038 value_id
= get_or_alloc_constant_value_id (constant
);
1039 get_or_alloc_expression_id (newexpr
);
1040 add_to_value (value_id
, newexpr
);
1044 /* Given a value id V, find the actual tree representing the constant
1045 value if there is one, and return it. Return NULL if we can't find
1049 get_constant_for_value_id (unsigned int v
)
1051 if (value_id_constant_p (v
))
1055 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, v
);
1057 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
1059 pre_expr expr
= expression_for_id (i
);
1060 if (expr
->kind
== CONSTANT
)
1061 return PRE_EXPR_CONSTANT (expr
);
1067 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1068 Currently only supports constants and SSA_NAMES. */
1070 get_or_alloc_expr_for (tree t
)
1072 if (TREE_CODE (t
) == SSA_NAME
)
1073 return get_or_alloc_expr_for_name (t
);
1074 else if (is_gimple_min_invariant (t
)
1075 || TREE_CODE (t
) == EXC_PTR_EXPR
1076 || TREE_CODE (t
) == FILTER_EXPR
)
1077 return get_or_alloc_expr_for_constant (t
);
1080 /* More complex expressions can result from SCCVN expression
1081 simplification that inserts values for them. As they all
1082 do not have VOPs the get handled by the nary ops struct. */
1083 vn_nary_op_t result
;
1084 unsigned int result_id
;
1085 vn_nary_op_lookup (t
, &result
);
1088 pre_expr e
= (pre_expr
) pool_alloc (pre_expr_pool
);
1090 PRE_EXPR_NARY (e
) = result
;
1091 result_id
= lookup_expression_id (e
);
1094 pool_free (pre_expr_pool
, e
);
1095 e
= expression_for_id (result_id
);
1098 alloc_expression_id (e
);
1105 /* Return the folded version of T if T, when folded, is a gimple
1106 min_invariant. Otherwise, return T. */
1109 fully_constant_expression (pre_expr e
)
1117 vn_nary_op_t nary
= PRE_EXPR_NARY (e
);
1118 switch (TREE_CODE_CLASS (nary
->opcode
))
1120 case tcc_expression
:
1121 if (nary
->opcode
== TRUTH_NOT_EXPR
)
1123 if (nary
->opcode
!= TRUTH_AND_EXPR
1124 && nary
->opcode
!= TRUTH_OR_EXPR
1125 && nary
->opcode
!= TRUTH_XOR_EXPR
)
1129 case tcc_comparison
:
1131 /* We have to go from trees to pre exprs to value ids to
1133 tree naryop0
= nary
->op
[0];
1134 tree naryop1
= nary
->op
[1];
1136 if (!is_gimple_min_invariant (naryop0
))
1138 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1139 unsigned int vrep0
= get_expr_value_id (rep0
);
1140 tree const0
= get_constant_for_value_id (vrep0
);
1142 naryop0
= fold_convert (TREE_TYPE (naryop0
), const0
);
1144 if (!is_gimple_min_invariant (naryop1
))
1146 pre_expr rep1
= get_or_alloc_expr_for (naryop1
);
1147 unsigned int vrep1
= get_expr_value_id (rep1
);
1148 tree const1
= get_constant_for_value_id (vrep1
);
1150 naryop1
= fold_convert (TREE_TYPE (naryop1
), const1
);
1152 result
= fold_binary (nary
->opcode
, nary
->type
,
1154 if (result
&& is_gimple_min_invariant (result
))
1155 return get_or_alloc_expr_for_constant (result
);
1156 /* We might have simplified the expression to a
1157 SSA_NAME for example from x_1 * 1. But we cannot
1158 insert a PHI for x_1 unconditionally as x_1 might
1159 not be available readily. */
1163 if (nary
->opcode
!= REALPART_EXPR
1164 && nary
->opcode
!= IMAGPART_EXPR
1165 && nary
->opcode
!= VIEW_CONVERT_EXPR
)
1171 /* We have to go from trees to pre exprs to value ids to
1173 tree naryop0
= nary
->op
[0];
1174 tree const0
, result
;
1175 if (is_gimple_min_invariant (naryop0
))
1179 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1180 unsigned int vrep0
= get_expr_value_id (rep0
);
1181 const0
= get_constant_for_value_id (vrep0
);
1186 tree type1
= TREE_TYPE (nary
->op
[0]);
1187 const0
= fold_convert (type1
, const0
);
1188 result
= fold_unary (nary
->opcode
, nary
->type
, const0
);
1190 if (result
&& is_gimple_min_invariant (result
))
1191 return get_or_alloc_expr_for_constant (result
);
1200 vn_reference_t ref
= PRE_EXPR_REFERENCE (e
);
1201 VEC (vn_reference_op_s
, heap
) *operands
= ref
->operands
;
1202 vn_reference_op_t op
;
1204 /* Try to simplify the translated expression if it is
1205 a call to a builtin function with at most two arguments. */
1206 op
= VEC_index (vn_reference_op_s
, operands
, 0);
1207 if (op
->opcode
== CALL_EXPR
1208 && TREE_CODE (op
->op0
) == ADDR_EXPR
1209 && TREE_CODE (TREE_OPERAND (op
->op0
, 0)) == FUNCTION_DECL
1210 && DECL_BUILT_IN (TREE_OPERAND (op
->op0
, 0))
1211 && VEC_length (vn_reference_op_s
, operands
) >= 2
1212 && VEC_length (vn_reference_op_s
, operands
) <= 3)
1214 vn_reference_op_t arg0
, arg1
= NULL
;
1215 bool anyconst
= false;
1216 arg0
= VEC_index (vn_reference_op_s
, operands
, 1);
1217 if (VEC_length (vn_reference_op_s
, operands
) > 2)
1218 arg1
= VEC_index (vn_reference_op_s
, operands
, 2);
1219 if (TREE_CODE_CLASS (arg0
->opcode
) == tcc_constant
1220 || (arg0
->opcode
== ADDR_EXPR
1221 && is_gimple_min_invariant (arg0
->op0
)))
1224 && (TREE_CODE_CLASS (arg1
->opcode
) == tcc_constant
1225 || (arg1
->opcode
== ADDR_EXPR
1226 && is_gimple_min_invariant (arg1
->op0
))))
1230 tree folded
= build_call_expr (TREE_OPERAND (op
->op0
, 0),
1233 arg1
? arg1
->op0
: NULL
);
1235 && TREE_CODE (folded
) == NOP_EXPR
)
1236 folded
= TREE_OPERAND (folded
, 0);
1238 && is_gimple_min_invariant (folded
))
1239 return get_or_alloc_expr_for_constant (folded
);
1250 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1251 it has the value it would have in BLOCK. */
1254 translate_vuse_through_block (VEC (vn_reference_op_s
, heap
) *operands
,
1255 alias_set_type set
, tree type
, tree vuse
,
1256 basic_block phiblock
,
1259 gimple phi
= SSA_NAME_DEF_STMT (vuse
);
1262 if (gimple_bb (phi
) != phiblock
)
1265 if (gimple_code (phi
) == GIMPLE_PHI
)
1267 edge e
= find_edge (block
, phiblock
);
1268 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1271 if (!ao_ref_init_from_vn_reference (&ref
, set
, type
, operands
))
1274 /* Use the alias-oracle to find either the PHI node in this block,
1275 the first VUSE used in this block that is equivalent to vuse or
1276 the first VUSE which definition in this block kills the value. */
1277 while (!stmt_may_clobber_ref_p_1 (phi
, &ref
))
1279 vuse
= gimple_vuse (phi
);
1280 phi
= SSA_NAME_DEF_STMT (vuse
);
1281 if (gimple_bb (phi
) != phiblock
)
1283 if (gimple_code (phi
) == GIMPLE_PHI
)
1285 edge e
= find_edge (block
, phiblock
);
1286 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1293 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1294 SET2. This is used to avoid making a set consisting of the union
1295 of PA_IN and ANTIC_IN during insert. */
1297 static inline pre_expr
1298 find_leader_in_sets (unsigned int val
, bitmap_set_t set1
, bitmap_set_t set2
)
1302 result
= bitmap_find_leader (set1
, val
, NULL
);
1303 if (!result
&& set2
)
1304 result
= bitmap_find_leader (set2
, val
, NULL
);
1308 /* Get the tree type for our PRE expression e. */
1311 get_expr_type (const pre_expr e
)
1316 return TREE_TYPE (PRE_EXPR_NAME (e
));
1318 return TREE_TYPE (PRE_EXPR_CONSTANT (e
));
1320 return PRE_EXPR_REFERENCE (e
)->type
;
1322 return PRE_EXPR_NARY (e
)->type
;
1327 /* Get a representative SSA_NAME for a given expression.
1328 Since all of our sub-expressions are treated as values, we require
1329 them to be SSA_NAME's for simplicity.
1330 Prior versions of GVNPRE used to use "value handles" here, so that
1331 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1332 either case, the operands are really values (IE we do not expect
1333 them to be usable without finding leaders). */
1336 get_representative_for (const pre_expr e
)
1340 unsigned int value_id
= get_expr_value_id (e
);
1345 return PRE_EXPR_NAME (e
);
1347 return PRE_EXPR_CONSTANT (e
);
1351 /* Go through all of the expressions representing this value
1352 and pick out an SSA_NAME. */
1355 bitmap_set_t exprs
= VEC_index (bitmap_set_t
, value_expressions
,
1357 FOR_EACH_EXPR_ID_IN_SET (exprs
, i
, bi
)
1359 pre_expr rep
= expression_for_id (i
);
1360 if (rep
->kind
== NAME
)
1361 return PRE_EXPR_NAME (rep
);
1366 /* If we reached here we couldn't find an SSA_NAME. This can
1367 happen when we've discovered a value that has never appeared in
1368 the program as set to an SSA_NAME, most likely as the result of
1373 "Could not find SSA_NAME representative for expression:");
1374 print_pre_expr (dump_file
, e
);
1375 fprintf (dump_file
, "\n");
1378 exprtype
= get_expr_type (e
);
1380 /* Build and insert the assignment of the end result to the temporary
1381 that we will return. */
1382 if (!pretemp
|| exprtype
!= TREE_TYPE (pretemp
))
1384 pretemp
= create_tmp_var (exprtype
, "pretmp");
1385 get_var_ann (pretemp
);
1388 name
= make_ssa_name (pretemp
, gimple_build_nop ());
1389 VN_INFO_GET (name
)->value_id
= value_id
;
1390 if (e
->kind
== CONSTANT
)
1391 VN_INFO (name
)->valnum
= PRE_EXPR_CONSTANT (e
);
1393 VN_INFO (name
)->valnum
= name
;
1395 add_to_value (value_id
, get_or_alloc_expr_for_name (name
));
1398 fprintf (dump_file
, "Created SSA_NAME representative ");
1399 print_generic_expr (dump_file
, name
, 0);
1400 fprintf (dump_file
, " for expression:");
1401 print_pre_expr (dump_file
, e
);
1402 fprintf (dump_file
, "\n");
1411 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1412 the phis in PRED. SEEN is a bitmap saying which expression we have
1413 translated since we started translation of the toplevel expression.
1414 Return NULL if we can't find a leader for each part of the
1415 translated expression. */
1418 phi_translate_1 (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1419 basic_block pred
, basic_block phiblock
, bitmap seen
)
1421 pre_expr oldexpr
= expr
;
1427 if (value_id_constant_p (get_expr_value_id (expr
)))
1430 phitrans
= phi_trans_lookup (expr
, pred
);
1434 /* Prevent cycles when we have recursively dependent leaders. This
1435 can only happen when phi translating the maximal set. */
1438 unsigned int expr_id
= get_expression_id (expr
);
1439 if (bitmap_bit_p (seen
, expr_id
))
1441 bitmap_set_bit (seen
, expr_id
);
1446 /* Constants contain no values that need translation. */
1453 bool changed
= false;
1454 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1455 struct vn_nary_op_s newnary
;
1456 /* The NARY structure is only guaranteed to have been
1457 allocated to the nary->length operands. */
1458 memcpy (&newnary
, nary
, (sizeof (struct vn_nary_op_s
)
1459 - sizeof (tree
) * (4 - nary
->length
)));
1461 for (i
= 0; i
< newnary
.length
; i
++)
1463 if (TREE_CODE (newnary
.op
[i
]) != SSA_NAME
)
1467 unsigned int op_val_id
= VN_INFO (newnary
.op
[i
])->value_id
;
1468 pre_expr leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1469 pre_expr result
= phi_translate_1 (leader
, set1
, set2
,
1470 pred
, phiblock
, seen
);
1471 if (result
&& result
!= leader
)
1473 tree name
= get_representative_for (result
);
1476 newnary
.op
[i
] = name
;
1481 changed
|= newnary
.op
[i
] != nary
->op
[i
];
1488 tree result
= vn_nary_op_lookup_pieces (newnary
.length
,
1496 unsigned int new_val_id
;
1498 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1501 if (result
&& is_gimple_min_invariant (result
))
1502 return get_or_alloc_expr_for_constant (result
);
1507 PRE_EXPR_NARY (expr
) = nary
;
1508 constant
= fully_constant_expression (expr
);
1509 if (constant
!= expr
)
1512 new_val_id
= nary
->value_id
;
1513 get_or_alloc_expression_id (expr
);
1517 new_val_id
= get_next_value_id ();
1518 VEC_safe_grow_cleared (bitmap_set_t
, heap
,
1520 get_max_value_id() + 1);
1521 nary
= vn_nary_op_insert_pieces (newnary
.length
,
1528 result
, new_val_id
);
1529 PRE_EXPR_NARY (expr
) = nary
;
1530 constant
= fully_constant_expression (expr
);
1531 if (constant
!= expr
)
1533 get_or_alloc_expression_id (expr
);
1535 add_to_value (new_val_id
, expr
);
1537 phi_trans_add (oldexpr
, expr
, pred
);
1544 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1545 VEC (vn_reference_op_s
, heap
) *operands
= ref
->operands
;
1546 tree vuse
= ref
->vuse
;
1547 tree newvuse
= vuse
;
1548 VEC (vn_reference_op_s
, heap
) *newoperands
= NULL
;
1549 bool changed
= false;
1551 vn_reference_op_t operand
;
1552 vn_reference_t newref
;
1555 VEC_iterate (vn_reference_op_s
, operands
, i
, operand
); i
++, j
++)
1559 tree oldop0
= operand
->op0
;
1560 tree oldop1
= operand
->op1
;
1561 tree oldop2
= operand
->op2
;
1565 tree type
= operand
->type
;
1566 vn_reference_op_s newop
= *operand
;
1568 if (op0
&& TREE_CODE (op0
) == SSA_NAME
)
1570 unsigned int op_val_id
= VN_INFO (op0
)->value_id
;
1571 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1572 opresult
= phi_translate_1 (leader
, set1
, set2
,
1573 pred
, phiblock
, seen
);
1574 if (opresult
&& opresult
!= leader
)
1576 tree name
= get_representative_for (opresult
);
1584 changed
|= op0
!= oldop0
;
1586 if (op1
&& TREE_CODE (op1
) == SSA_NAME
)
1588 unsigned int op_val_id
= VN_INFO (op1
)->value_id
;
1589 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1590 opresult
= phi_translate_1 (leader
, set1
, set2
,
1591 pred
, phiblock
, seen
);
1592 if (opresult
&& opresult
!= leader
)
1594 tree name
= get_representative_for (opresult
);
1602 changed
|= op1
!= oldop1
;
1603 if (op2
&& TREE_CODE (op2
) == SSA_NAME
)
1605 unsigned int op_val_id
= VN_INFO (op2
)->value_id
;
1606 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1607 opresult
= phi_translate_1 (leader
, set1
, set2
,
1608 pred
, phiblock
, seen
);
1609 if (opresult
&& opresult
!= leader
)
1611 tree name
= get_representative_for (opresult
);
1619 changed
|= op2
!= oldop2
;
1622 newoperands
= VEC_copy (vn_reference_op_s
, heap
, operands
);
1623 /* We may have changed from an SSA_NAME to a constant */
1624 if (newop
.opcode
== SSA_NAME
&& TREE_CODE (op0
) != SSA_NAME
)
1625 newop
.opcode
= TREE_CODE (op0
);
1630 VEC_replace (vn_reference_op_s
, newoperands
, j
, &newop
);
1631 /* If it transforms from an SSA_NAME to an address, fold with
1632 a preceding indirect reference. */
1633 if (j
> 0 && op0
&& TREE_CODE (op0
) == ADDR_EXPR
1634 && VEC_index (vn_reference_op_s
,
1635 newoperands
, j
- 1)->opcode
== INDIRECT_REF
)
1636 vn_reference_fold_indirect (&newoperands
, &j
);
1638 if (i
!= VEC_length (vn_reference_op_s
, operands
))
1641 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1647 newvuse
= translate_vuse_through_block (newoperands
,
1648 ref
->set
, ref
->type
,
1649 vuse
, phiblock
, pred
);
1650 if (newvuse
== NULL_TREE
)
1652 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1656 changed
|= newvuse
!= vuse
;
1660 unsigned int new_val_id
;
1663 tree result
= vn_reference_lookup_pieces (newvuse
, ref
->set
,
1668 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1670 if (result
&& is_gimple_min_invariant (result
))
1672 gcc_assert (!newoperands
);
1673 return get_or_alloc_expr_for_constant (result
);
1676 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1677 expr
->kind
= REFERENCE
;
1682 PRE_EXPR_REFERENCE (expr
) = newref
;
1683 constant
= fully_constant_expression (expr
);
1684 if (constant
!= expr
)
1687 new_val_id
= newref
->value_id
;
1688 get_or_alloc_expression_id (expr
);
1692 new_val_id
= get_next_value_id ();
1693 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
1694 get_max_value_id() + 1);
1695 newref
= vn_reference_insert_pieces (newvuse
, ref
->set
,
1698 result
, new_val_id
);
1700 PRE_EXPR_REFERENCE (expr
) = newref
;
1701 constant
= fully_constant_expression (expr
);
1702 if (constant
!= expr
)
1704 get_or_alloc_expression_id (expr
);
1706 add_to_value (new_val_id
, expr
);
1708 VEC_free (vn_reference_op_s
, heap
, newoperands
);
1709 phi_trans_add (oldexpr
, expr
, pred
);
1719 tree name
= PRE_EXPR_NAME (expr
);
1721 def_stmt
= SSA_NAME_DEF_STMT (name
);
1722 if (gimple_code (def_stmt
) == GIMPLE_PHI
1723 && gimple_bb (def_stmt
) == phiblock
)
1728 e
= find_edge (pred
, gimple_bb (phi
));
1731 tree def
= PHI_ARG_DEF (phi
, e
->dest_idx
);
1734 if (TREE_CODE (def
) == SSA_NAME
)
1735 def
= VN_INFO (def
)->valnum
;
1737 /* Handle constant. */
1738 if (is_gimple_min_invariant (def
))
1739 return get_or_alloc_expr_for_constant (def
);
1741 if (TREE_CODE (def
) == SSA_NAME
&& ssa_undefined_value_p (def
))
1744 newexpr
= get_or_alloc_expr_for_name (def
);
1755 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1757 Return NULL if we can't find a leader for each part of the
1758 translated expression. */
1761 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1762 basic_block pred
, basic_block phiblock
)
1764 bitmap_clear (seen_during_translate
);
1765 return phi_translate_1 (expr
, set1
, set2
, pred
, phiblock
,
1766 seen_during_translate
);
1769 /* For each expression in SET, translate the values through phi nodes
1770 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1771 expressions in DEST. */
1774 phi_translate_set (bitmap_set_t dest
, bitmap_set_t set
, basic_block pred
,
1775 basic_block phiblock
)
1777 VEC (pre_expr
, heap
) *exprs
;
1781 if (!phi_nodes (phiblock
))
1783 bitmap_set_copy (dest
, set
);
1787 exprs
= sorted_array_from_bitmap_set (set
);
1788 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
1790 pre_expr translated
;
1791 translated
= phi_translate (expr
, set
, NULL
, pred
, phiblock
);
1793 /* Don't add empty translations to the cache */
1795 phi_trans_add (expr
, translated
, pred
);
1797 if (translated
!= NULL
)
1798 bitmap_value_insert_into_set (dest
, translated
);
1800 VEC_free (pre_expr
, heap
, exprs
);
1803 /* Find the leader for a value (i.e., the name representing that
1804 value) in a given set, and return it. If STMT is non-NULL it
1805 makes sure the defining statement for the leader dominates it.
1806 Return NULL if no leader is found. */
1809 bitmap_find_leader (bitmap_set_t set
, unsigned int val
, gimple stmt
)
1811 if (value_id_constant_p (val
))
1815 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1817 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
1819 pre_expr expr
= expression_for_id (i
);
1820 if (expr
->kind
== CONSTANT
)
1824 if (bitmap_set_contains_value (set
, val
))
1826 /* Rather than walk the entire bitmap of expressions, and see
1827 whether any of them has the value we are looking for, we look
1828 at the reverse mapping, which tells us the set of expressions
1829 that have a given value (IE value->expressions with that
1830 value) and see if any of those expressions are in our set.
1831 The number of expressions per value is usually significantly
1832 less than the number of expressions in the set. In fact, for
1833 large testcases, doing it this way is roughly 5-10x faster
1834 than walking the bitmap.
1835 If this is somehow a significant lose for some cases, we can
1836 choose which set to walk based on which set is smaller. */
1839 bitmap_set_t exprset
= VEC_index (bitmap_set_t
, value_expressions
, val
);
1841 EXECUTE_IF_AND_IN_BITMAP (exprset
->expressions
,
1842 set
->expressions
, 0, i
, bi
)
1844 pre_expr val
= expression_for_id (i
);
1845 /* At the point where stmt is not null, there should always
1846 be an SSA_NAME first in the list of expressions. */
1849 gimple def_stmt
= SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val
));
1850 if (gimple_code (def_stmt
) != GIMPLE_PHI
1851 && gimple_bb (def_stmt
) == gimple_bb (stmt
)
1852 && gimple_uid (def_stmt
) >= gimple_uid (stmt
))
1861 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1862 BLOCK by seeing if it is not killed in the block. Note that we are
1863 only determining whether there is a store that kills it. Because
1864 of the order in which clean iterates over values, we are guaranteed
1865 that altered operands will have caused us to be eliminated from the
1866 ANTIC_IN set already. */
1869 value_dies_in_block_x (pre_expr expr
, basic_block block
)
1871 tree vuse
= PRE_EXPR_REFERENCE (expr
)->vuse
;
1872 vn_reference_t refx
= PRE_EXPR_REFERENCE (expr
);
1874 gimple_stmt_iterator gsi
;
1875 unsigned id
= get_expression_id (expr
);
1882 /* Lookup a previously calculated result. */
1883 if (EXPR_DIES (block
)
1884 && bitmap_bit_p (EXPR_DIES (block
), id
* 2))
1885 return bitmap_bit_p (EXPR_DIES (block
), id
* 2 + 1);
1887 /* A memory expression {e, VUSE} dies in the block if there is a
1888 statement that may clobber e. If, starting statement walk from the
1889 top of the basic block, a statement uses VUSE there can be no kill
1890 inbetween that use and the original statement that loaded {e, VUSE},
1891 so we can stop walking. */
1892 ref
.base
= NULL_TREE
;
1893 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1895 tree def_vuse
, def_vdef
;
1896 def
= gsi_stmt (gsi
);
1897 def_vuse
= gimple_vuse (def
);
1898 def_vdef
= gimple_vdef (def
);
1900 /* Not a memory statement. */
1904 /* Not a may-def. */
1907 /* A load with the same VUSE, we're done. */
1908 if (def_vuse
== vuse
)
1914 /* Init ref only if we really need it. */
1915 if (ref
.base
== NULL_TREE
1916 && !ao_ref_init_from_vn_reference (&ref
, refx
->set
, refx
->type
,
1922 /* If the statement may clobber expr, it dies. */
1923 if (stmt_may_clobber_ref_p_1 (def
, &ref
))
1930 /* Remember the result. */
1931 if (!EXPR_DIES (block
))
1932 EXPR_DIES (block
) = BITMAP_ALLOC (&grand_bitmap_obstack
);
1933 bitmap_set_bit (EXPR_DIES (block
), id
* 2);
1935 bitmap_set_bit (EXPR_DIES (block
), id
* 2 + 1);
1941 #define union_contains_value(SET1, SET2, VAL) \
1942 (bitmap_set_contains_value ((SET1), (VAL)) \
1943 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1945 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
1948 vro_valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
,
1949 vn_reference_op_t vro
)
1951 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
1953 struct pre_expr_d temp
;
1956 PRE_EXPR_NAME (&temp
) = vro
->op0
;
1957 temp
.id
= lookup_expression_id (&temp
);
1960 if (!union_contains_value (set1
, set2
,
1961 get_expr_value_id (&temp
)))
1964 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
1966 struct pre_expr_d temp
;
1969 PRE_EXPR_NAME (&temp
) = vro
->op1
;
1970 temp
.id
= lookup_expression_id (&temp
);
1973 if (!union_contains_value (set1
, set2
,
1974 get_expr_value_id (&temp
)))
1978 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
1980 struct pre_expr_d temp
;
1983 PRE_EXPR_NAME (&temp
) = vro
->op2
;
1984 temp
.id
= lookup_expression_id (&temp
);
1987 if (!union_contains_value (set1
, set2
,
1988 get_expr_value_id (&temp
)))
1995 /* Determine if the expression EXPR is valid in SET1 U SET2.
1996 ONLY SET2 CAN BE NULL.
1997 This means that we have a leader for each part of the expression
1998 (if it consists of values), or the expression is an SSA_NAME.
1999 For loads/calls, we also see if the vuse is killed in this block. */
2002 valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, pre_expr expr
,
2008 return bitmap_set_contains_expr (AVAIL_OUT (block
), expr
);
2012 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2013 for (i
= 0; i
< nary
->length
; i
++)
2015 if (TREE_CODE (nary
->op
[i
]) == SSA_NAME
)
2017 struct pre_expr_d temp
;
2020 PRE_EXPR_NAME (&temp
) = nary
->op
[i
];
2021 temp
.id
= lookup_expression_id (&temp
);
2024 if (!union_contains_value (set1
, set2
,
2025 get_expr_value_id (&temp
)))
2034 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2035 vn_reference_op_t vro
;
2038 for (i
= 0; VEC_iterate (vn_reference_op_s
, ref
->operands
, i
, vro
); i
++)
2040 if (!vro_valid_in_sets (set1
, set2
, vro
))
2045 gimple def_stmt
= SSA_NAME_DEF_STMT (ref
->vuse
);
2046 if (!gimple_nop_p (def_stmt
)
2047 && gimple_bb (def_stmt
) != block
2048 && !dominated_by_p (CDI_DOMINATORS
,
2049 block
, gimple_bb (def_stmt
)))
2052 return !value_dies_in_block_x (expr
, block
);
2059 /* Clean the set of expressions that are no longer valid in SET1 or
2060 SET2. This means expressions that are made up of values we have no
2061 leaders for in SET1 or SET2. This version is used for partial
2062 anticipation, which means it is not valid in either ANTIC_IN or
2066 dependent_clean (bitmap_set_t set1
, bitmap_set_t set2
, basic_block block
)
2068 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (set1
);
2072 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
2074 if (!valid_in_sets (set1
, set2
, expr
, block
))
2075 bitmap_remove_from_set (set1
, expr
);
2077 VEC_free (pre_expr
, heap
, exprs
);
2080 /* Clean the set of expressions that are no longer valid in SET. This
2081 means expressions that are made up of values we have no leaders for
2085 clean (bitmap_set_t set
, basic_block block
)
2087 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (set
);
2091 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
2093 if (!valid_in_sets (set
, NULL
, expr
, block
))
2094 bitmap_remove_from_set (set
, expr
);
2096 VEC_free (pre_expr
, heap
, exprs
);
2099 static sbitmap has_abnormal_preds
;
2101 /* List of blocks that may have changed during ANTIC computation and
2102 thus need to be iterated over. */
2104 static sbitmap changed_blocks
;
2106 /* Decide whether to defer a block for a later iteration, or PHI
2107 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2108 should defer the block, and true if we processed it. */
2111 defer_or_phi_translate_block (bitmap_set_t dest
, bitmap_set_t source
,
2112 basic_block block
, basic_block phiblock
)
2114 if (!BB_VISITED (phiblock
))
2116 SET_BIT (changed_blocks
, block
->index
);
2117 BB_VISITED (block
) = 0;
2118 BB_DEFERRED (block
) = 1;
2122 phi_translate_set (dest
, source
, block
, phiblock
);
2126 /* Compute the ANTIC set for BLOCK.
2128 If succs(BLOCK) > 1 then
2129 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2130 else if succs(BLOCK) == 1 then
2131 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2133 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2137 compute_antic_aux (basic_block block
, bool block_has_abnormal_pred_edge
)
2139 bool changed
= false;
2140 bitmap_set_t S
, old
, ANTIC_OUT
;
2146 old
= ANTIC_OUT
= S
= NULL
;
2147 BB_VISITED (block
) = 1;
2149 /* If any edges from predecessors are abnormal, antic_in is empty,
2151 if (block_has_abnormal_pred_edge
)
2152 goto maybe_dump_sets
;
2154 old
= ANTIC_IN (block
);
2155 ANTIC_OUT
= bitmap_set_new ();
2157 /* If the block has no successors, ANTIC_OUT is empty. */
2158 if (EDGE_COUNT (block
->succs
) == 0)
2160 /* If we have one successor, we could have some phi nodes to
2161 translate through. */
2162 else if (single_succ_p (block
))
2164 basic_block succ_bb
= single_succ (block
);
2166 /* We trade iterations of the dataflow equations for having to
2167 phi translate the maximal set, which is incredibly slow
2168 (since the maximal set often has 300+ members, even when you
2169 have a small number of blocks).
2170 Basically, we defer the computation of ANTIC for this block
2171 until we have processed it's successor, which will inevitably
2172 have a *much* smaller set of values to phi translate once
2173 clean has been run on it.
2174 The cost of doing this is that we technically perform more
2175 iterations, however, they are lower cost iterations.
2177 Timings for PRE on tramp3d-v4:
2178 without maximal set fix: 11 seconds
2179 with maximal set fix/without deferring: 26 seconds
2180 with maximal set fix/with deferring: 11 seconds
2183 if (!defer_or_phi_translate_block (ANTIC_OUT
, ANTIC_IN (succ_bb
),
2187 goto maybe_dump_sets
;
2190 /* If we have multiple successors, we take the intersection of all of
2191 them. Note that in the case of loop exit phi nodes, we may have
2192 phis to translate through. */
2195 VEC(basic_block
, heap
) * worklist
;
2197 basic_block bprime
, first
;
2199 worklist
= VEC_alloc (basic_block
, heap
, EDGE_COUNT (block
->succs
));
2200 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2201 VEC_quick_push (basic_block
, worklist
, e
->dest
);
2202 first
= VEC_index (basic_block
, worklist
, 0);
2204 if (phi_nodes (first
))
2206 bitmap_set_t from
= ANTIC_IN (first
);
2208 if (!BB_VISITED (first
))
2210 phi_translate_set (ANTIC_OUT
, from
, block
, first
);
2214 if (!BB_VISITED (first
))
2215 bitmap_set_copy (ANTIC_OUT
, maximal_set
);
2217 bitmap_set_copy (ANTIC_OUT
, ANTIC_IN (first
));
2220 for (i
= 1; VEC_iterate (basic_block
, worklist
, i
, bprime
); i
++)
2222 if (phi_nodes (bprime
))
2224 bitmap_set_t tmp
= bitmap_set_new ();
2225 bitmap_set_t from
= ANTIC_IN (bprime
);
2227 if (!BB_VISITED (bprime
))
2229 phi_translate_set (tmp
, from
, block
, bprime
);
2230 bitmap_set_and (ANTIC_OUT
, tmp
);
2231 bitmap_set_free (tmp
);
2235 if (!BB_VISITED (bprime
))
2236 bitmap_set_and (ANTIC_OUT
, maximal_set
);
2238 bitmap_set_and (ANTIC_OUT
, ANTIC_IN (bprime
));
2241 VEC_free (basic_block
, heap
, worklist
);
2244 /* Generate ANTIC_OUT - TMP_GEN. */
2245 S
= bitmap_set_subtract (ANTIC_OUT
, TMP_GEN (block
));
2247 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2248 ANTIC_IN (block
) = bitmap_set_subtract (EXP_GEN (block
),
2251 /* Then union in the ANTIC_OUT - TMP_GEN values,
2252 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2253 FOR_EACH_EXPR_ID_IN_SET (S
, bii
, bi
)
2254 bitmap_value_insert_into_set (ANTIC_IN (block
),
2255 expression_for_id (bii
));
2257 clean (ANTIC_IN (block
), block
);
2259 /* !old->expressions can happen when we deferred a block. */
2260 if (!old
->expressions
|| !bitmap_set_equal (old
, ANTIC_IN (block
)))
2263 SET_BIT (changed_blocks
, block
->index
);
2264 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2265 SET_BIT (changed_blocks
, e
->src
->index
);
2268 RESET_BIT (changed_blocks
, block
->index
);
2271 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2273 if (!BB_DEFERRED (block
) || BB_VISITED (block
))
2276 print_bitmap_set (dump_file
, ANTIC_OUT
, "ANTIC_OUT", block
->index
);
2278 print_bitmap_set (dump_file
, ANTIC_IN (block
), "ANTIC_IN",
2282 print_bitmap_set (dump_file
, S
, "S", block
->index
);
2287 "Block %d was deferred for a future iteration.\n",
2292 bitmap_set_free (old
);
2294 bitmap_set_free (S
);
2296 bitmap_set_free (ANTIC_OUT
);
2300 /* Compute PARTIAL_ANTIC for BLOCK.
2302 If succs(BLOCK) > 1 then
2303 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2304 in ANTIC_OUT for all succ(BLOCK)
2305 else if succs(BLOCK) == 1 then
2306 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2308 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2313 compute_partial_antic_aux (basic_block block
,
2314 bool block_has_abnormal_pred_edge
)
2316 bool changed
= false;
2317 bitmap_set_t old_PA_IN
;
2318 bitmap_set_t PA_OUT
;
2321 unsigned long max_pa
= PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH
);
2323 old_PA_IN
= PA_OUT
= NULL
;
2325 /* If any edges from predecessors are abnormal, antic_in is empty,
2327 if (block_has_abnormal_pred_edge
)
2328 goto maybe_dump_sets
;
2330 /* If there are too many partially anticipatable values in the
2331 block, phi_translate_set can take an exponential time: stop
2332 before the translation starts. */
2334 && single_succ_p (block
)
2335 && bitmap_count_bits (PA_IN (single_succ (block
))->values
) > max_pa
)
2336 goto maybe_dump_sets
;
2338 old_PA_IN
= PA_IN (block
);
2339 PA_OUT
= bitmap_set_new ();
2341 /* If the block has no successors, ANTIC_OUT is empty. */
2342 if (EDGE_COUNT (block
->succs
) == 0)
2344 /* If we have one successor, we could have some phi nodes to
2345 translate through. Note that we can't phi translate across DFS
2346 back edges in partial antic, because it uses a union operation on
2347 the successors. For recurrences like IV's, we will end up
2348 generating a new value in the set on each go around (i + 3 (VH.1)
2349 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2350 else if (single_succ_p (block
))
2352 basic_block succ
= single_succ (block
);
2353 if (!(single_succ_edge (block
)->flags
& EDGE_DFS_BACK
))
2354 phi_translate_set (PA_OUT
, PA_IN (succ
), block
, succ
);
2356 /* If we have multiple successors, we take the union of all of
2360 VEC(basic_block
, heap
) * worklist
;
2364 worklist
= VEC_alloc (basic_block
, heap
, EDGE_COUNT (block
->succs
));
2365 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2367 if (e
->flags
& EDGE_DFS_BACK
)
2369 VEC_quick_push (basic_block
, worklist
, e
->dest
);
2371 if (VEC_length (basic_block
, worklist
) > 0)
2373 for (i
= 0; VEC_iterate (basic_block
, worklist
, i
, bprime
); i
++)
2378 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime
), i
, bi
)
2379 bitmap_value_insert_into_set (PA_OUT
,
2380 expression_for_id (i
));
2381 if (phi_nodes (bprime
))
2383 bitmap_set_t pa_in
= bitmap_set_new ();
2384 phi_translate_set (pa_in
, PA_IN (bprime
), block
, bprime
);
2385 FOR_EACH_EXPR_ID_IN_SET (pa_in
, i
, bi
)
2386 bitmap_value_insert_into_set (PA_OUT
,
2387 expression_for_id (i
));
2388 bitmap_set_free (pa_in
);
2391 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime
), i
, bi
)
2392 bitmap_value_insert_into_set (PA_OUT
,
2393 expression_for_id (i
));
2396 VEC_free (basic_block
, heap
, worklist
);
2399 /* PA_IN starts with PA_OUT - TMP_GEN.
2400 Then we subtract things from ANTIC_IN. */
2401 PA_IN (block
) = bitmap_set_subtract (PA_OUT
, TMP_GEN (block
));
2403 /* For partial antic, we want to put back in the phi results, since
2404 we will properly avoid making them partially antic over backedges. */
2405 bitmap_ior_into (PA_IN (block
)->values
, PHI_GEN (block
)->values
);
2406 bitmap_ior_into (PA_IN (block
)->expressions
, PHI_GEN (block
)->expressions
);
2408 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2409 bitmap_set_subtract_values (PA_IN (block
), ANTIC_IN (block
));
2411 dependent_clean (PA_IN (block
), ANTIC_IN (block
), block
);
2413 if (!bitmap_set_equal (old_PA_IN
, PA_IN (block
)))
2416 SET_BIT (changed_blocks
, block
->index
);
2417 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2418 SET_BIT (changed_blocks
, e
->src
->index
);
2421 RESET_BIT (changed_blocks
, block
->index
);
2424 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2427 print_bitmap_set (dump_file
, PA_OUT
, "PA_OUT", block
->index
);
2429 print_bitmap_set (dump_file
, PA_IN (block
), "PA_IN", block
->index
);
2432 bitmap_set_free (old_PA_IN
);
2434 bitmap_set_free (PA_OUT
);
2438 /* Compute ANTIC and partial ANTIC sets. */
2441 compute_antic (void)
2443 bool changed
= true;
2444 int num_iterations
= 0;
2448 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2449 We pre-build the map of blocks with incoming abnormal edges here. */
2450 has_abnormal_preds
= sbitmap_alloc (last_basic_block
);
2451 sbitmap_zero (has_abnormal_preds
);
2458 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2460 e
->flags
&= ~EDGE_DFS_BACK
;
2461 if (e
->flags
& EDGE_ABNORMAL
)
2463 SET_BIT (has_abnormal_preds
, block
->index
);
2468 BB_VISITED (block
) = 0;
2469 BB_DEFERRED (block
) = 0;
2470 /* While we are here, give empty ANTIC_IN sets to each block. */
2471 ANTIC_IN (block
) = bitmap_set_new ();
2472 PA_IN (block
) = bitmap_set_new ();
2475 /* At the exit block we anticipate nothing. */
2476 ANTIC_IN (EXIT_BLOCK_PTR
) = bitmap_set_new ();
2477 BB_VISITED (EXIT_BLOCK_PTR
) = 1;
2478 PA_IN (EXIT_BLOCK_PTR
) = bitmap_set_new ();
2480 changed_blocks
= sbitmap_alloc (last_basic_block
+ 1);
2481 sbitmap_ones (changed_blocks
);
2484 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2485 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2488 for (i
= 0; i
< n_basic_blocks
- NUM_FIXED_BLOCKS
; i
++)
2490 if (TEST_BIT (changed_blocks
, postorder
[i
]))
2492 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2493 changed
|= compute_antic_aux (block
,
2494 TEST_BIT (has_abnormal_preds
,
2498 #ifdef ENABLE_CHECKING
2499 /* Theoretically possible, but *highly* unlikely. */
2500 gcc_assert (num_iterations
< 500);
2504 statistics_histogram_event (cfun
, "compute_antic iterations",
2507 if (do_partial_partial
)
2509 sbitmap_ones (changed_blocks
);
2510 mark_dfs_back_edges ();
2515 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2516 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2519 for (i
= 0; i
< n_basic_blocks
- NUM_FIXED_BLOCKS
; i
++)
2521 if (TEST_BIT (changed_blocks
, postorder
[i
]))
2523 basic_block block
= BASIC_BLOCK (postorder
[i
]);
2525 |= compute_partial_antic_aux (block
,
2526 TEST_BIT (has_abnormal_preds
,
2530 #ifdef ENABLE_CHECKING
2531 /* Theoretically possible, but *highly* unlikely. */
2532 gcc_assert (num_iterations
< 500);
2535 statistics_histogram_event (cfun
, "compute_partial_antic iterations",
2538 sbitmap_free (has_abnormal_preds
);
2539 sbitmap_free (changed_blocks
);
2542 /* Return true if we can value number the call in STMT. This is true
2543 if we have a pure or constant call. */
2546 can_value_number_call (gimple stmt
)
2548 if (gimple_call_flags (stmt
) & (ECF_PURE
| ECF_CONST
))
2553 /* Return true if OP is an exception handler related operation, such as
2554 FILTER_EXPR or EXC_PTR_EXPR. */
2557 is_exception_related (gimple stmt
)
2559 return (is_gimple_assign (stmt
)
2560 && (gimple_assign_rhs_code (stmt
) == FILTER_EXPR
2561 || gimple_assign_rhs_code (stmt
) == EXC_PTR_EXPR
));
2564 /* Return true if OP is a tree which we can perform PRE on.
2565 This may not match the operations we can value number, but in
2566 a perfect world would. */
2569 can_PRE_operation (tree op
)
2571 return UNARY_CLASS_P (op
)
2572 || BINARY_CLASS_P (op
)
2573 || COMPARISON_CLASS_P (op
)
2574 || TREE_CODE (op
) == INDIRECT_REF
2575 || TREE_CODE (op
) == COMPONENT_REF
2576 || TREE_CODE (op
) == VIEW_CONVERT_EXPR
2577 || TREE_CODE (op
) == CALL_EXPR
2578 || TREE_CODE (op
) == ARRAY_REF
;
2582 /* Inserted expressions are placed onto this worklist, which is used
2583 for performing quick dead code elimination of insertions we made
2584 that didn't turn out to be necessary. */
2585 static VEC(gimple
,heap
) *inserted_exprs
;
2586 static bitmap inserted_phi_names
;
2588 /* Pool allocated fake store expressions are placed onto this
2589 worklist, which, after performing dead code elimination, is walked
2590 to see which expressions need to be put into GC'able memory */
2591 static VEC(gimple
, heap
) *need_creation
;
2593 /* The actual worker for create_component_ref_by_pieces. */
2596 create_component_ref_by_pieces_1 (basic_block block
, vn_reference_t ref
,
2597 unsigned int *operand
, gimple_seq
*stmts
,
2600 vn_reference_op_t currop
= VEC_index (vn_reference_op_s
, ref
->operands
,
2604 switch (currop
->opcode
)
2608 tree folded
, sc
= currop
->op1
;
2609 unsigned int nargs
= 0;
2610 tree
*args
= XNEWVEC (tree
, VEC_length (vn_reference_op_s
,
2611 ref
->operands
) - 1);
2612 while (*operand
< VEC_length (vn_reference_op_s
, ref
->operands
))
2614 args
[nargs
] = create_component_ref_by_pieces_1 (block
, ref
,
2619 folded
= build_call_array (currop
->type
,
2620 TREE_CODE (currop
->op0
) == FUNCTION_DECL
2621 ? build_fold_addr_expr (currop
->op0
)
2627 pre_expr scexpr
= get_or_alloc_expr_for (sc
);
2628 sc
= find_or_generate_expression (block
, scexpr
, stmts
, domstmt
);
2631 CALL_EXPR_STATIC_CHAIN (folded
) = sc
;
2636 case TARGET_MEM_REF
:
2638 vn_reference_op_t nextop
= VEC_index (vn_reference_op_s
, ref
->operands
,
2641 tree genop0
= NULL_TREE
;
2642 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2648 op0expr
= get_or_alloc_expr_for (currop
->op0
);
2649 genop0
= find_or_generate_expression (block
, op0expr
,
2654 if (DECL_P (baseop
))
2655 return build6 (TARGET_MEM_REF
, currop
->type
,
2657 genop0
, currop
->op1
, currop
->op2
,
2658 unshare_expr (nextop
->op1
));
2660 return build6 (TARGET_MEM_REF
, currop
->type
,
2662 genop0
, currop
->op1
, currop
->op2
,
2663 unshare_expr (nextop
->op1
));
2669 gcc_assert (is_gimple_min_invariant (currop
->op0
));
2675 case VIEW_CONVERT_EXPR
:
2678 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
,
2683 folded
= fold_build1 (currop
->opcode
, currop
->type
,
2688 case ALIGN_INDIRECT_REF
:
2689 case MISALIGNED_INDIRECT_REF
:
2693 tree genop1
= create_component_ref_by_pieces_1 (block
, ref
,
2698 genop1
= fold_convert (build_pointer_type (currop
->type
),
2701 if (currop
->opcode
== MISALIGNED_INDIRECT_REF
)
2702 folded
= fold_build2 (currop
->opcode
, currop
->type
,
2703 genop1
, currop
->op1
);
2705 folded
= fold_build1 (currop
->opcode
, currop
->type
,
2713 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2715 pre_expr op1expr
= get_or_alloc_expr_for (currop
->op0
);
2716 pre_expr op2expr
= get_or_alloc_expr_for (currop
->op1
);
2722 genop1
= find_or_generate_expression (block
, op1expr
, stmts
, domstmt
);
2725 genop2
= find_or_generate_expression (block
, op2expr
, stmts
, domstmt
);
2728 folded
= fold_build3 (BIT_FIELD_REF
, currop
->type
, genop0
, genop1
,
2733 /* For array ref vn_reference_op's, operand 1 of the array ref
2734 is op0 of the reference op and operand 3 of the array ref is
2736 case ARRAY_RANGE_REF
:
2740 tree genop1
= currop
->op0
;
2742 tree genop2
= currop
->op1
;
2745 genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2749 op1expr
= get_or_alloc_expr_for (genop1
);
2750 genop1
= find_or_generate_expression (block
, op1expr
, stmts
, domstmt
);
2755 op2expr
= get_or_alloc_expr_for (genop2
);
2756 genop2
= find_or_generate_expression (block
, op2expr
, stmts
,
2762 genop3
= currop
->op2
;
2763 return build4 (currop
->opcode
, currop
->type
, genop0
, genop1
,
2770 tree genop2
= currop
->op1
;
2772 op0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2776 /* op1 should be a FIELD_DECL, which are represented by
2781 op2expr
= get_or_alloc_expr_for (genop2
);
2782 genop2
= find_or_generate_expression (block
, op2expr
, stmts
,
2788 return fold_build3 (COMPONENT_REF
, TREE_TYPE (op1
), op0
, op1
,
2794 pre_expr op0expr
= get_or_alloc_expr_for (currop
->op0
);
2795 genop
= find_or_generate_expression (block
, op0expr
, stmts
, domstmt
);
2816 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2817 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2818 trying to rename aggregates into ssa form directly, which is a no no.
2820 Thus, this routine doesn't create temporaries, it just builds a
2821 single access expression for the array, calling
2822 find_or_generate_expression to build the innermost pieces.
2824 This function is a subroutine of create_expression_by_pieces, and
2825 should not be called on it's own unless you really know what you
2829 create_component_ref_by_pieces (basic_block block
, vn_reference_t ref
,
2830 gimple_seq
*stmts
, gimple domstmt
)
2832 unsigned int op
= 0;
2833 return create_component_ref_by_pieces_1 (block
, ref
, &op
, stmts
, domstmt
);
2836 /* Find a leader for an expression, or generate one using
2837 create_expression_by_pieces if it's ANTIC but
2839 BLOCK is the basic_block we are looking for leaders in.
2840 EXPR is the expression to find a leader or generate for.
2841 STMTS is the statement list to put the inserted expressions on.
2842 Returns the SSA_NAME of the LHS of the generated expression or the
2844 DOMSTMT if non-NULL is a statement that should be dominated by
2845 all uses in the generated expression. If DOMSTMT is non-NULL this
2846 routine can fail and return NULL_TREE. Otherwise it will assert
2850 find_or_generate_expression (basic_block block
, pre_expr expr
,
2851 gimple_seq
*stmts
, gimple domstmt
)
2853 pre_expr leader
= bitmap_find_leader (AVAIL_OUT (block
),
2854 get_expr_value_id (expr
), domstmt
);
2858 if (leader
->kind
== NAME
)
2859 genop
= PRE_EXPR_NAME (leader
);
2860 else if (leader
->kind
== CONSTANT
)
2861 genop
= PRE_EXPR_CONSTANT (leader
);
2864 /* If it's still NULL, it must be a complex expression, so generate
2865 it recursively. Not so for FRE though. */
2869 bitmap_set_t exprset
;
2870 unsigned int lookfor
= get_expr_value_id (expr
);
2871 bool handled
= false;
2875 exprset
= VEC_index (bitmap_set_t
, value_expressions
, lookfor
);
2876 FOR_EACH_EXPR_ID_IN_SET (exprset
, i
, bi
)
2878 pre_expr temp
= expression_for_id (i
);
2879 if (temp
->kind
!= NAME
)
2882 genop
= create_expression_by_pieces (block
, temp
, stmts
,
2884 get_expr_type (expr
));
2888 if (!handled
&& domstmt
)
2891 gcc_assert (handled
);
2896 #define NECESSARY GF_PLF_1
2898 /* Create an expression in pieces, so that we can handle very complex
2899 expressions that may be ANTIC, but not necessary GIMPLE.
2900 BLOCK is the basic block the expression will be inserted into,
2901 EXPR is the expression to insert (in value form)
2902 STMTS is a statement list to append the necessary insertions into.
2904 This function will die if we hit some value that shouldn't be
2905 ANTIC but is (IE there is no leader for it, or its components).
2906 This function may also generate expressions that are themselves
2907 partially or fully redundant. Those that are will be either made
2908 fully redundant during the next iteration of insert (for partially
2909 redundant ones), or eliminated by eliminate (for fully redundant
2912 If DOMSTMT is non-NULL then we make sure that all uses in the
2913 expressions dominate that statement. In this case the function
2914 can return NULL_TREE to signal failure. */
2917 create_expression_by_pieces (basic_block block
, pre_expr expr
,
2918 gimple_seq
*stmts
, gimple domstmt
, tree type
)
2922 gimple_seq forced_stmts
= NULL
;
2923 unsigned int value_id
;
2924 gimple_stmt_iterator gsi
;
2925 tree exprtype
= type
? type
: get_expr_type (expr
);
2931 /* We may hit the NAME/CONSTANT case if we have to convert types
2932 that value numbering saw through. */
2934 folded
= PRE_EXPR_NAME (expr
);
2937 folded
= PRE_EXPR_CONSTANT (expr
);
2941 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2942 folded
= create_component_ref_by_pieces (block
, ref
, stmts
, domstmt
);
2947 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2948 switch (nary
->length
)
2952 pre_expr op1
= get_or_alloc_expr_for (nary
->op
[0]);
2953 pre_expr op2
= get_or_alloc_expr_for (nary
->op
[1]);
2954 tree genop1
= find_or_generate_expression (block
, op1
,
2956 tree genop2
= find_or_generate_expression (block
, op2
,
2958 if (!genop1
|| !genop2
)
2960 genop1
= fold_convert (TREE_TYPE (nary
->op
[0]),
2962 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
2963 may be a constant with the wrong type. */
2964 if (nary
->opcode
== POINTER_PLUS_EXPR
)
2965 genop2
= fold_convert (sizetype
, genop2
);
2967 genop2
= fold_convert (TREE_TYPE (nary
->op
[1]), genop2
);
2969 folded
= fold_build2 (nary
->opcode
, nary
->type
,
2975 pre_expr op1
= get_or_alloc_expr_for (nary
->op
[0]);
2976 tree genop1
= find_or_generate_expression (block
, op1
,
2980 genop1
= fold_convert (TREE_TYPE (nary
->op
[0]), genop1
);
2982 folded
= fold_build1 (nary
->opcode
, nary
->type
,
2995 if (!useless_type_conversion_p (exprtype
, TREE_TYPE (folded
)))
2996 folded
= fold_convert (exprtype
, folded
);
2998 /* Force the generated expression to be a sequence of GIMPLE
3000 We have to call unshare_expr because force_gimple_operand may
3001 modify the tree we pass to it. */
3002 folded
= force_gimple_operand (unshare_expr (folded
), &forced_stmts
,
3005 /* If we have any intermediate expressions to the value sets, add them
3006 to the value sets and chain them in the instruction stream. */
3009 gsi
= gsi_start (forced_stmts
);
3010 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3012 gimple stmt
= gsi_stmt (gsi
);
3013 tree forcedname
= gimple_get_lhs (stmt
);
3016 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3017 if (TREE_CODE (forcedname
) == SSA_NAME
)
3019 VN_INFO_GET (forcedname
)->valnum
= forcedname
;
3020 VN_INFO (forcedname
)->value_id
= get_next_value_id ();
3021 nameexpr
= get_or_alloc_expr_for_name (forcedname
);
3022 add_to_value (VN_INFO (forcedname
)->value_id
, nameexpr
);
3024 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3025 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3027 mark_symbols_for_renaming (stmt
);
3029 gimple_seq_add_seq (stmts
, forced_stmts
);
3032 /* Build and insert the assignment of the end result to the temporary
3033 that we will return. */
3034 if (!pretemp
|| exprtype
!= TREE_TYPE (pretemp
))
3036 pretemp
= create_tmp_var (exprtype
, "pretmp");
3037 get_var_ann (pretemp
);
3041 add_referenced_var (temp
);
3043 if (TREE_CODE (exprtype
) == COMPLEX_TYPE
3044 || TREE_CODE (exprtype
) == VECTOR_TYPE
)
3045 DECL_GIMPLE_REG_P (temp
) = 1;
3047 newstmt
= gimple_build_assign (temp
, folded
);
3048 name
= make_ssa_name (temp
, newstmt
);
3049 gimple_assign_set_lhs (newstmt
, name
);
3050 gimple_set_plf (newstmt
, NECESSARY
, false);
3052 gimple_seq_add_stmt (stmts
, newstmt
);
3053 VEC_safe_push (gimple
, heap
, inserted_exprs
, newstmt
);
3055 /* All the symbols in NEWEXPR should be put into SSA form. */
3056 mark_symbols_for_renaming (newstmt
);
3058 /* Add a value number to the temporary.
3059 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3060 we are creating the expression by pieces, and this particular piece of
3061 the expression may have been represented. There is no harm in replacing
3063 VN_INFO_GET (name
)->valnum
= name
;
3064 value_id
= get_expr_value_id (expr
);
3065 VN_INFO (name
)->value_id
= value_id
;
3066 nameexpr
= get_or_alloc_expr_for_name (name
);
3067 add_to_value (value_id
, nameexpr
);
3069 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3070 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3072 pre_stats
.insertions
++;
3073 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3075 fprintf (dump_file
, "Inserted ");
3076 print_gimple_stmt (dump_file
, newstmt
, 0, 0);
3077 fprintf (dump_file
, " in predecessor %d\n", block
->index
);
3084 /* Insert the to-be-made-available values of expression EXPRNUM for each
3085 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3086 merge the result with a phi node, given the same value number as
3087 NODE. Return true if we have inserted new stuff. */
3090 insert_into_preds_of_block (basic_block block
, unsigned int exprnum
,
3093 pre_expr expr
= expression_for_id (exprnum
);
3095 unsigned int val
= get_expr_value_id (expr
);
3097 bool insertions
= false;
3102 tree type
= get_expr_type (expr
);
3106 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3108 fprintf (dump_file
, "Found partial redundancy for expression ");
3109 print_pre_expr (dump_file
, expr
);
3110 fprintf (dump_file
, " (%04d)\n", val
);
3113 /* Make sure we aren't creating an induction variable. */
3114 if (block
->loop_depth
> 0 && EDGE_COUNT (block
->preds
) == 2
3115 && expr
->kind
!= REFERENCE
)
3117 bool firstinsideloop
= false;
3118 bool secondinsideloop
= false;
3119 firstinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3120 EDGE_PRED (block
, 0)->src
);
3121 secondinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3122 EDGE_PRED (block
, 1)->src
);
3123 /* Induction variables only have one edge inside the loop. */
3124 if (firstinsideloop
^ secondinsideloop
)
3126 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3127 fprintf (dump_file
, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3132 /* Make sure we are not inserting trapping expressions. */
3133 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3136 eprime
= avail
[bprime
->index
];
3137 if (eprime
->kind
== NARY
3138 && vn_nary_may_trap (PRE_EXPR_NARY (eprime
)))
3142 /* Make the necessary insertions. */
3143 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3145 gimple_seq stmts
= NULL
;
3148 eprime
= avail
[bprime
->index
];
3150 if (eprime
->kind
!= NAME
&& eprime
->kind
!= CONSTANT
)
3152 builtexpr
= create_expression_by_pieces (bprime
,
3156 gcc_assert (!(pred
->flags
& EDGE_ABNORMAL
));
3157 gsi_insert_seq_on_edge (pred
, stmts
);
3158 avail
[bprime
->index
] = get_or_alloc_expr_for_name (builtexpr
);
3161 else if (eprime
->kind
== CONSTANT
)
3163 /* Constants may not have the right type, fold_convert
3164 should give us back a constant with the right type.
3166 tree constant
= PRE_EXPR_CONSTANT (eprime
);
3167 if (!useless_type_conversion_p (type
, TREE_TYPE (constant
)))
3169 tree builtexpr
= fold_convert (type
, constant
);
3170 if (!is_gimple_min_invariant (builtexpr
))
3172 tree forcedexpr
= force_gimple_operand (builtexpr
,
3175 if (!is_gimple_min_invariant (forcedexpr
))
3177 if (forcedexpr
!= builtexpr
)
3179 VN_INFO_GET (forcedexpr
)->valnum
= PRE_EXPR_CONSTANT (eprime
);
3180 VN_INFO (forcedexpr
)->value_id
= get_expr_value_id (eprime
);
3184 gimple_stmt_iterator gsi
;
3185 gsi
= gsi_start (stmts
);
3186 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3188 gimple stmt
= gsi_stmt (gsi
);
3189 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3190 gimple_set_plf (stmt
, NECESSARY
, false);
3192 gsi_insert_seq_on_edge (pred
, stmts
);
3194 avail
[bprime
->index
] = get_or_alloc_expr_for_name (forcedexpr
);
3199 else if (eprime
->kind
== NAME
)
3201 /* We may have to do a conversion because our value
3202 numbering can look through types in certain cases, but
3203 our IL requires all operands of a phi node have the same
3205 tree name
= PRE_EXPR_NAME (eprime
);
3206 if (!useless_type_conversion_p (type
, TREE_TYPE (name
)))
3210 builtexpr
= fold_convert (type
, name
);
3211 forcedexpr
= force_gimple_operand (builtexpr
,
3215 if (forcedexpr
!= name
)
3217 VN_INFO_GET (forcedexpr
)->valnum
= VN_INFO (name
)->valnum
;
3218 VN_INFO (forcedexpr
)->value_id
= VN_INFO (name
)->value_id
;
3223 gimple_stmt_iterator gsi
;
3224 gsi
= gsi_start (stmts
);
3225 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3227 gimple stmt
= gsi_stmt (gsi
);
3228 VEC_safe_push (gimple
, heap
, inserted_exprs
, stmt
);
3229 gimple_set_plf (stmt
, NECESSARY
, false);
3231 gsi_insert_seq_on_edge (pred
, stmts
);
3233 avail
[bprime
->index
] = get_or_alloc_expr_for_name (forcedexpr
);
3237 /* If we didn't want a phi node, and we made insertions, we still have
3238 inserted new stuff, and thus return true. If we didn't want a phi node,
3239 and didn't make insertions, we haven't added anything new, so return
3241 if (nophi
&& insertions
)
3243 else if (nophi
&& !insertions
)
3246 /* Now build a phi for the new variable. */
3247 if (!prephitemp
|| TREE_TYPE (prephitemp
) != type
)
3249 prephitemp
= create_tmp_var (type
, "prephitmp");
3250 get_var_ann (prephitemp
);
3254 add_referenced_var (temp
);
3256 if (TREE_CODE (type
) == COMPLEX_TYPE
3257 || TREE_CODE (type
) == VECTOR_TYPE
)
3258 DECL_GIMPLE_REG_P (temp
) = 1;
3259 phi
= create_phi_node (temp
, block
);
3261 gimple_set_plf (phi
, NECESSARY
, false);
3262 VN_INFO_GET (gimple_phi_result (phi
))->valnum
= gimple_phi_result (phi
);
3263 VN_INFO (gimple_phi_result (phi
))->value_id
= val
;
3264 VEC_safe_push (gimple
, heap
, inserted_exprs
, phi
);
3265 bitmap_set_bit (inserted_phi_names
,
3266 SSA_NAME_VERSION (gimple_phi_result (phi
)));
3267 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3269 pre_expr ae
= avail
[pred
->src
->index
];
3270 gcc_assert (get_expr_type (ae
) == type
3271 || useless_type_conversion_p (type
, get_expr_type (ae
)));
3272 if (ae
->kind
== CONSTANT
)
3273 add_phi_arg (phi
, PRE_EXPR_CONSTANT (ae
), pred
);
3275 add_phi_arg (phi
, PRE_EXPR_NAME (avail
[pred
->src
->index
]), pred
);
3278 newphi
= get_or_alloc_expr_for_name (gimple_phi_result (phi
));
3279 add_to_value (val
, newphi
);
3281 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3282 this insertion, since we test for the existence of this value in PHI_GEN
3283 before proceeding with the partial redundancy checks in insert_aux.
3285 The value may exist in AVAIL_OUT, in particular, it could be represented
3286 by the expression we are trying to eliminate, in which case we want the
3287 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3290 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3291 this block, because if it did, it would have existed in our dominator's
3292 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3295 bitmap_insert_into_set (PHI_GEN (block
), newphi
);
3296 bitmap_value_replace_in_set (AVAIL_OUT (block
),
3298 bitmap_insert_into_set (NEW_SETS (block
),
3301 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3303 fprintf (dump_file
, "Created phi ");
3304 print_gimple_stmt (dump_file
, phi
, 0, 0);
3305 fprintf (dump_file
, " in block %d\n", block
->index
);
3313 /* Perform insertion of partially redundant values.
3314 For BLOCK, do the following:
3315 1. Propagate the NEW_SETS of the dominator into the current block.
3316 If the block has multiple predecessors,
3317 2a. Iterate over the ANTIC expressions for the block to see if
3318 any of them are partially redundant.
3319 2b. If so, insert them into the necessary predecessors to make
3320 the expression fully redundant.
3321 2c. Insert a new PHI merging the values of the predecessors.
3322 2d. Insert the new PHI, and the new expressions, into the
3324 3. Recursively call ourselves on the dominator children of BLOCK.
3326 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3327 do_regular_insertion and do_partial_insertion.
3332 do_regular_insertion (basic_block block
, basic_block dom
)
3334 bool new_stuff
= false;
3335 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (ANTIC_IN (block
));
3339 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
3341 if (expr
->kind
!= NAME
)
3345 bool by_some
= false;
3346 bool cant_insert
= false;
3347 bool all_same
= true;
3348 pre_expr first_s
= NULL
;
3351 pre_expr eprime
= NULL
;
3353 pre_expr edoubleprime
= NULL
;
3355 val
= get_expr_value_id (expr
);
3356 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3358 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3360 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3361 fprintf (dump_file
, "Found fully redundant value\n");
3365 avail
= XCNEWVEC (pre_expr
, last_basic_block
);
3366 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3368 unsigned int vprime
;
3370 /* We should never run insertion for the exit block
3371 and so not come across fake pred edges. */
3372 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3374 eprime
= phi_translate (expr
, ANTIC_IN (block
), NULL
,
3377 /* eprime will generally only be NULL if the
3378 value of the expression, translated
3379 through the PHI for this predecessor, is
3380 undefined. If that is the case, we can't
3381 make the expression fully redundant,
3382 because its value is undefined along a
3383 predecessor path. We can thus break out
3384 early because it doesn't matter what the
3385 rest of the results are. */
3392 eprime
= fully_constant_expression (eprime
);
3393 vprime
= get_expr_value_id (eprime
);
3394 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3396 if (edoubleprime
== NULL
)
3398 avail
[bprime
->index
] = eprime
;
3403 avail
[bprime
->index
] = edoubleprime
;
3405 if (first_s
== NULL
)
3406 first_s
= edoubleprime
;
3407 else if (!pre_expr_eq (first_s
, edoubleprime
))
3411 /* If we can insert it, it's not the same value
3412 already existing along every predecessor, and
3413 it's defined by some predecessor, it is
3414 partially redundant. */
3415 if (!cant_insert
&& !all_same
&& by_some
&& dbg_cnt (treepre_insert
))
3417 if (insert_into_preds_of_block (block
, get_expression_id (expr
),
3421 /* If all edges produce the same value and that value is
3422 an invariant, then the PHI has the same value on all
3423 edges. Note this. */
3424 else if (!cant_insert
&& all_same
&& eprime
3425 && (edoubleprime
->kind
== CONSTANT
3426 || edoubleprime
->kind
== NAME
)
3427 && !value_id_constant_p (val
))
3431 bitmap_set_t exprset
= VEC_index (bitmap_set_t
,
3432 value_expressions
, val
);
3434 unsigned int new_val
= get_expr_value_id (edoubleprime
);
3435 FOR_EACH_EXPR_ID_IN_SET (exprset
, j
, bi
)
3437 pre_expr expr
= expression_for_id (j
);
3439 if (expr
->kind
== NAME
)
3441 vn_ssa_aux_t info
= VN_INFO (PRE_EXPR_NAME (expr
));
3442 /* Just reset the value id and valnum so it is
3443 the same as the constant we have discovered. */
3444 if (edoubleprime
->kind
== CONSTANT
)
3446 info
->valnum
= PRE_EXPR_CONSTANT (edoubleprime
);
3447 pre_stats
.constified
++;
3450 info
->valnum
= VN_INFO (PRE_EXPR_NAME (edoubleprime
))->valnum
;
3451 info
->value_id
= new_val
;
3459 VEC_free (pre_expr
, heap
, exprs
);
3464 /* Perform insertion for partially anticipatable expressions. There
3465 is only one case we will perform insertion for these. This case is
3466 if the expression is partially anticipatable, and fully available.
3467 In this case, we know that putting it earlier will enable us to
3468 remove the later computation. */
3472 do_partial_partial_insertion (basic_block block
, basic_block dom
)
3474 bool new_stuff
= false;
3475 VEC (pre_expr
, heap
) *exprs
= sorted_array_from_bitmap_set (PA_IN (block
));
3479 for (i
= 0; VEC_iterate (pre_expr
, exprs
, i
, expr
); i
++)
3481 if (expr
->kind
!= NAME
)
3486 bool cant_insert
= false;
3489 pre_expr eprime
= NULL
;
3492 val
= get_expr_value_id (expr
);
3493 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3495 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3498 avail
= XCNEWVEC (pre_expr
, last_basic_block
);
3499 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3501 unsigned int vprime
;
3502 pre_expr edoubleprime
;
3504 /* We should never run insertion for the exit block
3505 and so not come across fake pred edges. */
3506 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3508 eprime
= phi_translate (expr
, ANTIC_IN (block
),
3512 /* eprime will generally only be NULL if the
3513 value of the expression, translated
3514 through the PHI for this predecessor, is
3515 undefined. If that is the case, we can't
3516 make the expression fully redundant,
3517 because its value is undefined along a
3518 predecessor path. We can thus break out
3519 early because it doesn't matter what the
3520 rest of the results are. */
3527 eprime
= fully_constant_expression (eprime
);
3528 vprime
= get_expr_value_id (eprime
);
3529 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3531 if (edoubleprime
== NULL
)
3537 avail
[bprime
->index
] = edoubleprime
;
3541 /* If we can insert it, it's not the same value
3542 already existing along every predecessor, and
3543 it's defined by some predecessor, it is
3544 partially redundant. */
3545 if (!cant_insert
&& by_all
&& dbg_cnt (treepre_insert
))
3547 pre_stats
.pa_insert
++;
3548 if (insert_into_preds_of_block (block
, get_expression_id (expr
),
3556 VEC_free (pre_expr
, heap
, exprs
);
3561 insert_aux (basic_block block
)
3564 bool new_stuff
= false;
3569 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3574 bitmap_set_t newset
= NEW_SETS (dom
);
3577 /* Note that we need to value_replace both NEW_SETS, and
3578 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3579 represented by some non-simple expression here that we want
3580 to replace it with. */
3581 FOR_EACH_EXPR_ID_IN_SET (newset
, i
, bi
)
3583 pre_expr expr
= expression_for_id (i
);
3584 bitmap_value_replace_in_set (NEW_SETS (block
), expr
);
3585 bitmap_value_replace_in_set (AVAIL_OUT (block
), expr
);
3588 if (!single_pred_p (block
))
3590 new_stuff
|= do_regular_insertion (block
, dom
);
3591 if (do_partial_partial
)
3592 new_stuff
|= do_partial_partial_insertion (block
, dom
);
3596 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3598 son
= next_dom_son (CDI_DOMINATORS
, son
))
3600 new_stuff
|= insert_aux (son
);
3606 /* Perform insertion of partially redundant values. */
3611 bool new_stuff
= true;
3613 int num_iterations
= 0;
3616 NEW_SETS (bb
) = bitmap_set_new ();
3621 new_stuff
= insert_aux (ENTRY_BLOCK_PTR
);
3623 statistics_histogram_event (cfun
, "insert iterations", num_iterations
);
3627 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3630 add_to_exp_gen (basic_block block
, tree op
)
3635 if (TREE_CODE (op
) == SSA_NAME
&& ssa_undefined_value_p (op
))
3637 result
= get_or_alloc_expr_for_name (op
);
3638 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3639 bitmap_value_insert_into_set (maximal_set
, result
);
3643 /* Create value ids for PHI in BLOCK. */
3646 make_values_for_phi (gimple phi
, basic_block block
)
3648 tree result
= gimple_phi_result (phi
);
3650 /* We have no need for virtual phis, as they don't represent
3651 actual computations. */
3652 if (is_gimple_reg (result
))
3654 pre_expr e
= get_or_alloc_expr_for_name (result
);
3655 add_to_value (get_expr_value_id (e
), e
);
3656 bitmap_insert_into_set (PHI_GEN (block
), e
);
3657 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3661 for (i
= 0; i
< gimple_phi_num_args (phi
); ++i
)
3663 tree arg
= gimple_phi_arg_def (phi
, i
);
3664 if (TREE_CODE (arg
) == SSA_NAME
)
3666 e
= get_or_alloc_expr_for_name (arg
);
3667 add_to_value (get_expr_value_id (e
), e
);
3668 bitmap_value_insert_into_set (maximal_set
, e
);
3675 /* Compute the AVAIL set for all basic blocks.
3677 This function performs value numbering of the statements in each basic
3678 block. The AVAIL sets are built from information we glean while doing
3679 this value numbering, since the AVAIL sets contain only one entry per
3682 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3683 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3686 compute_avail (void)
3689 basic_block block
, son
;
3690 basic_block
*worklist
;
3694 /* We pretend that default definitions are defined in the entry block.
3695 This includes function arguments and the static chain decl. */
3696 for (i
= 1; i
< num_ssa_names
; ++i
)
3698 tree name
= ssa_name (i
);
3701 || !SSA_NAME_IS_DEFAULT_DEF (name
)
3702 || has_zero_uses (name
)
3703 || !is_gimple_reg (name
))
3706 e
= get_or_alloc_expr_for_name (name
);
3707 add_to_value (get_expr_value_id (e
), e
);
3710 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR
), e
);
3711 bitmap_value_insert_into_set (maximal_set
, e
);
3713 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR
), e
);
3716 /* Allocate the worklist. */
3717 worklist
= XNEWVEC (basic_block
, n_basic_blocks
);
3719 /* Seed the algorithm by putting the dominator children of the entry
3720 block on the worklist. */
3721 for (son
= first_dom_son (CDI_DOMINATORS
, ENTRY_BLOCK_PTR
);
3723 son
= next_dom_son (CDI_DOMINATORS
, son
))
3724 worklist
[sp
++] = son
;
3726 /* Loop until the worklist is empty. */
3729 gimple_stmt_iterator gsi
;
3732 unsigned int stmt_uid
= 1;
3734 /* Pick a block from the worklist. */
3735 block
= worklist
[--sp
];
3737 /* Initially, the set of available values in BLOCK is that of
3738 its immediate dominator. */
3739 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3741 bitmap_set_copy (AVAIL_OUT (block
), AVAIL_OUT (dom
));
3743 /* Generate values for PHI nodes. */
3744 for (gsi
= gsi_start_phis (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3745 make_values_for_phi (gsi_stmt (gsi
), block
);
3747 /* Now compute value numbers and populate value sets with all
3748 the expressions computed in BLOCK. */
3749 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3754 stmt
= gsi_stmt (gsi
);
3755 gimple_set_uid (stmt
, stmt_uid
++);
3757 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
3759 pre_expr e
= get_or_alloc_expr_for_name (op
);
3761 add_to_value (get_expr_value_id (e
), e
);
3763 bitmap_insert_into_set (TMP_GEN (block
), e
);
3764 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3767 if (gimple_has_volatile_ops (stmt
)
3768 || stmt_could_throw_p (stmt
))
3771 switch (gimple_code (stmt
))
3774 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3775 add_to_exp_gen (block
, op
);
3782 vn_reference_op_t vro
;
3783 pre_expr result
= NULL
;
3784 VEC(vn_reference_op_s
, heap
) *ops
= NULL
;
3786 if (!can_value_number_call (stmt
))
3789 copy_reference_ops_from_call (stmt
, &ops
);
3790 vn_reference_lookup_pieces (gimple_vuse (stmt
), 0,
3791 gimple_expr_type (stmt
),
3793 VEC_free (vn_reference_op_s
, heap
, ops
);
3797 for (i
= 0; VEC_iterate (vn_reference_op_s
,
3801 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
3802 add_to_exp_gen (block
, vro
->op0
);
3803 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
3804 add_to_exp_gen (block
, vro
->op1
);
3805 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
3806 add_to_exp_gen (block
, vro
->op2
);
3808 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3809 result
->kind
= REFERENCE
;
3811 PRE_EXPR_REFERENCE (result
) = ref
;
3813 get_or_alloc_expression_id (result
);
3814 add_to_value (get_expr_value_id (result
), result
);
3817 bitmap_value_insert_into_set (EXP_GEN (block
),
3819 bitmap_value_insert_into_set (maximal_set
, result
);
3826 pre_expr result
= NULL
;
3827 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)))
3830 if (is_exception_related (stmt
))
3833 case tcc_comparison
:
3838 vn_nary_op_lookup_pieces (gimple_num_ops (stmt
) - 1,
3839 gimple_assign_rhs_code (stmt
),
3840 gimple_expr_type (stmt
),
3841 gimple_assign_rhs1 (stmt
),
3842 gimple_assign_rhs2 (stmt
),
3843 NULL_TREE
, NULL_TREE
, &nary
);
3848 for (i
= 0; i
< nary
->length
; i
++)
3849 if (TREE_CODE (nary
->op
[i
]) == SSA_NAME
)
3850 add_to_exp_gen (block
, nary
->op
[i
]);
3852 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3853 result
->kind
= NARY
;
3855 PRE_EXPR_NARY (result
) = nary
;
3859 case tcc_declaration
:
3864 vn_reference_op_t vro
;
3866 vn_reference_lookup (gimple_assign_rhs1 (stmt
),
3872 for (i
= 0; VEC_iterate (vn_reference_op_s
,
3876 if (vro
->op0
&& TREE_CODE (vro
->op0
) == SSA_NAME
)
3877 add_to_exp_gen (block
, vro
->op0
);
3878 if (vro
->op1
&& TREE_CODE (vro
->op1
) == SSA_NAME
)
3879 add_to_exp_gen (block
, vro
->op1
);
3880 if (vro
->op2
&& TREE_CODE (vro
->op2
) == SSA_NAME
)
3881 add_to_exp_gen (block
, vro
->op2
);
3883 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3884 result
->kind
= REFERENCE
;
3886 PRE_EXPR_REFERENCE (result
) = ref
;
3891 /* For any other statement that we don't
3892 recognize, simply add all referenced
3893 SSA_NAMEs to EXP_GEN. */
3894 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3895 add_to_exp_gen (block
, op
);
3899 get_or_alloc_expression_id (result
);
3900 add_to_value (get_expr_value_id (result
), result
);
3903 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3904 bitmap_value_insert_into_set (maximal_set
, result
);
3914 /* Put the dominator children of BLOCK on the worklist of blocks
3915 to compute available sets for. */
3916 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3918 son
= next_dom_son (CDI_DOMINATORS
, son
))
3919 worklist
[sp
++] = son
;
3925 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
3926 than the available expressions for it. The insertion point is
3927 right before the first use in STMT. Returns the SSA_NAME that should
3928 be used for replacement. */
3931 do_SCCVN_insertion (gimple stmt
, tree ssa_vn
)
3933 basic_block bb
= gimple_bb (stmt
);
3934 gimple_stmt_iterator gsi
;
3935 gimple_seq stmts
= NULL
;
3939 /* First create a value expression from the expression we want
3940 to insert and associate it with the value handle for SSA_VN. */
3941 e
= get_or_alloc_expr_for (vn_get_expr_for (ssa_vn
));
3945 /* Then use create_expression_by_pieces to generate a valid
3946 expression to insert at this point of the IL stream. */
3947 expr
= create_expression_by_pieces (bb
, e
, &stmts
, stmt
, NULL
);
3948 if (expr
== NULL_TREE
)
3950 gsi
= gsi_for_stmt (stmt
);
3951 gsi_insert_seq_before (&gsi
, stmts
, GSI_SAME_STMT
);
3956 /* Eliminate fully redundant computations. */
3961 VEC (gimple
, heap
) *to_remove
= NULL
;
3963 unsigned int todo
= 0;
3964 gimple_stmt_iterator gsi
;
3970 for (gsi
= gsi_start_bb (b
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3972 stmt
= gsi_stmt (gsi
);
3974 /* Lookup the RHS of the expression, see if we have an
3975 available computation for it. If so, replace the RHS with
3976 the available computation. */
3977 if (gimple_has_lhs (stmt
)
3978 && TREE_CODE (gimple_get_lhs (stmt
)) == SSA_NAME
3979 && !gimple_assign_ssa_name_copy_p (stmt
)
3980 && (!gimple_assign_single_p (stmt
)
3981 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3982 && !gimple_has_volatile_ops (stmt
)
3983 && !has_zero_uses (gimple_get_lhs (stmt
)))
3985 tree lhs
= gimple_get_lhs (stmt
);
3986 tree rhs
= NULL_TREE
;
3988 pre_expr lhsexpr
= get_or_alloc_expr_for_name (lhs
);
3989 pre_expr sprimeexpr
;
3991 if (gimple_assign_single_p (stmt
))
3992 rhs
= gimple_assign_rhs1 (stmt
);
3994 sprimeexpr
= bitmap_find_leader (AVAIL_OUT (b
),
3995 get_expr_value_id (lhsexpr
),
4000 if (sprimeexpr
->kind
== CONSTANT
)
4001 sprime
= PRE_EXPR_CONSTANT (sprimeexpr
);
4002 else if (sprimeexpr
->kind
== NAME
)
4003 sprime
= PRE_EXPR_NAME (sprimeexpr
);
4008 /* If there is no existing leader but SCCVN knows this
4009 value is constant, use that constant. */
4010 if (!sprime
&& is_gimple_min_invariant (VN_INFO (lhs
)->valnum
))
4012 sprime
= VN_INFO (lhs
)->valnum
;
4013 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
4014 TREE_TYPE (sprime
)))
4015 sprime
= fold_convert (TREE_TYPE (lhs
), sprime
);
4017 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4019 fprintf (dump_file
, "Replaced ");
4020 print_gimple_expr (dump_file
, stmt
, 0, 0);
4021 fprintf (dump_file
, " with ");
4022 print_generic_expr (dump_file
, sprime
, 0);
4023 fprintf (dump_file
, " in ");
4024 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4026 pre_stats
.eliminations
++;
4027 propagate_tree_value_into_stmt (&gsi
, sprime
);
4028 stmt
= gsi_stmt (gsi
);
4033 /* If there is no existing usable leader but SCCVN thinks
4034 it has an expression it wants to use as replacement,
4036 if (!sprime
|| sprime
== lhs
)
4038 tree val
= VN_INFO (lhs
)->valnum
;
4040 && TREE_CODE (val
) == SSA_NAME
4041 && VN_INFO (val
)->needs_insertion
4042 && can_PRE_operation (vn_get_expr_for (val
)))
4043 sprime
= do_SCCVN_insertion (stmt
, val
);
4047 && (rhs
== NULL_TREE
4048 || TREE_CODE (rhs
) != SSA_NAME
4049 || may_propagate_copy (rhs
, sprime
)))
4051 gcc_assert (sprime
!= rhs
);
4053 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4055 fprintf (dump_file
, "Replaced ");
4056 print_gimple_expr (dump_file
, stmt
, 0, 0);
4057 fprintf (dump_file
, " with ");
4058 print_generic_expr (dump_file
, sprime
, 0);
4059 fprintf (dump_file
, " in ");
4060 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4063 if (TREE_CODE (sprime
) == SSA_NAME
)
4064 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4066 /* We need to make sure the new and old types actually match,
4067 which may require adding a simple cast, which fold_convert
4069 if ((!rhs
|| TREE_CODE (rhs
) != SSA_NAME
)
4070 && !useless_type_conversion_p (gimple_expr_type (stmt
),
4071 TREE_TYPE (sprime
)))
4072 sprime
= fold_convert (gimple_expr_type (stmt
), sprime
);
4074 pre_stats
.eliminations
++;
4075 propagate_tree_value_into_stmt (&gsi
, sprime
);
4076 stmt
= gsi_stmt (gsi
);
4079 /* If we removed EH side effects from the statement, clean
4080 its EH information. */
4081 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4083 bitmap_set_bit (need_eh_cleanup
,
4084 gimple_bb (stmt
)->index
);
4085 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4086 fprintf (dump_file
, " Removed EH side effects.\n");
4090 /* If the statement is a scalar store, see if the expression
4091 has the same value number as its rhs. If so, the store is
4093 else if (gimple_assign_single_p (stmt
)
4094 && !is_gimple_reg (gimple_assign_lhs (stmt
))
4095 && (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
4096 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt
))))
4098 tree rhs
= gimple_assign_rhs1 (stmt
);
4100 val
= vn_reference_lookup (gimple_assign_lhs (stmt
),
4101 gimple_vuse (stmt
), true, NULL
);
4102 if (TREE_CODE (rhs
) == SSA_NAME
)
4103 rhs
= VN_INFO (rhs
)->valnum
;
4105 && operand_equal_p (val
, rhs
, 0))
4107 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4109 fprintf (dump_file
, "Deleted redundant store ");
4110 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4113 /* Queue stmt for removal. */
4114 VEC_safe_push (gimple
, heap
, to_remove
, stmt
);
4117 /* Visit COND_EXPRs and fold the comparison with the
4118 available value-numbers. */
4119 else if (gimple_code (stmt
) == GIMPLE_COND
)
4121 tree op0
= gimple_cond_lhs (stmt
);
4122 tree op1
= gimple_cond_rhs (stmt
);
4125 if (TREE_CODE (op0
) == SSA_NAME
)
4126 op0
= VN_INFO (op0
)->valnum
;
4127 if (TREE_CODE (op1
) == SSA_NAME
)
4128 op1
= VN_INFO (op1
)->valnum
;
4129 result
= fold_binary (gimple_cond_code (stmt
), boolean_type_node
,
4131 if (result
&& TREE_CODE (result
) == INTEGER_CST
)
4133 if (integer_zerop (result
))
4134 gimple_cond_make_false (stmt
);
4136 gimple_cond_make_true (stmt
);
4138 todo
= TODO_cleanup_cfg
;
4141 /* Visit indirect calls and turn them into direct calls if
4143 if (gimple_code (stmt
) == GIMPLE_CALL
4144 && TREE_CODE (gimple_call_fn (stmt
)) == SSA_NAME
)
4146 tree fn
= VN_INFO (gimple_call_fn (stmt
))->valnum
;
4147 if (TREE_CODE (fn
) == ADDR_EXPR
4148 && TREE_CODE (TREE_OPERAND (fn
, 0)) == FUNCTION_DECL
)
4150 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4152 fprintf (dump_file
, "Replacing call target with ");
4153 print_generic_expr (dump_file
, fn
, 0);
4154 fprintf (dump_file
, " in ");
4155 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4158 gimple_call_set_fn (stmt
, fn
);
4160 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4161 gimple_purge_dead_eh_edges (b
);
4163 /* Changing an indirect call to a direct call may
4164 have exposed different semantics. This may
4165 require an SSA update. */
4166 todo
|= TODO_update_ssa_only_virtuals
;
4171 for (gsi
= gsi_start_phis (b
); !gsi_end_p (gsi
);)
4173 gimple stmt
, phi
= gsi_stmt (gsi
);
4174 tree sprime
= NULL_TREE
, res
= PHI_RESULT (phi
);
4175 pre_expr sprimeexpr
, resexpr
;
4176 gimple_stmt_iterator gsi2
;
4178 /* We want to perform redundant PHI elimination. Do so by
4179 replacing the PHI with a single copy if possible.
4180 Do not touch inserted, single-argument or virtual PHIs. */
4181 if (gimple_phi_num_args (phi
) == 1
4182 || !is_gimple_reg (res
)
4183 || bitmap_bit_p (inserted_phi_names
, SSA_NAME_VERSION (res
)))
4189 resexpr
= get_or_alloc_expr_for_name (res
);
4190 sprimeexpr
= bitmap_find_leader (AVAIL_OUT (b
),
4191 get_expr_value_id (resexpr
), NULL
);
4194 if (sprimeexpr
->kind
== CONSTANT
)
4195 sprime
= PRE_EXPR_CONSTANT (sprimeexpr
);
4196 else if (sprimeexpr
->kind
== NAME
)
4197 sprime
= PRE_EXPR_NAME (sprimeexpr
);
4208 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4210 fprintf (dump_file
, "Replaced redundant PHI node defining ");
4211 print_generic_expr (dump_file
, res
, 0);
4212 fprintf (dump_file
, " with ");
4213 print_generic_expr (dump_file
, sprime
, 0);
4214 fprintf (dump_file
, "\n");
4217 remove_phi_node (&gsi
, false);
4219 if (!useless_type_conversion_p (TREE_TYPE (res
), TREE_TYPE (sprime
)))
4220 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4221 stmt
= gimple_build_assign (res
, sprime
);
4222 SSA_NAME_DEF_STMT (res
) = stmt
;
4223 if (TREE_CODE (sprime
) == SSA_NAME
)
4224 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4226 gsi2
= gsi_after_labels (b
);
4227 gsi_insert_before (&gsi2
, stmt
, GSI_NEW_STMT
);
4228 /* Queue the copy for eventual removal. */
4229 VEC_safe_push (gimple
, heap
, to_remove
, stmt
);
4230 pre_stats
.eliminations
++;
4234 /* We cannot remove stmts during BB walk, especially not release SSA
4235 names there as this confuses the VN machinery. The stmts ending
4236 up in to_remove are either stores or simple copies. */
4237 for (i
= 0; VEC_iterate (gimple
, to_remove
, i
, stmt
); ++i
)
4239 tree lhs
= gimple_assign_lhs (stmt
);
4240 use_operand_p use_p
;
4243 /* If there is a single use only, propagate the equivalency
4244 instead of keeping the copy. */
4245 if (TREE_CODE (lhs
) == SSA_NAME
4246 && single_imm_use (lhs
, &use_p
, &use_stmt
)
4247 && may_propagate_copy (USE_FROM_PTR (use_p
),
4248 gimple_assign_rhs1 (stmt
)))
4250 SET_USE (use_p
, gimple_assign_rhs1 (stmt
));
4251 update_stmt (use_stmt
);
4254 /* If this is a store or a now unused copy, remove it. */
4255 if (TREE_CODE (lhs
) != SSA_NAME
4256 || has_zero_uses (lhs
))
4258 gsi
= gsi_for_stmt (stmt
);
4259 unlink_stmt_vdef (stmt
);
4260 gsi_remove (&gsi
, true);
4261 release_defs (stmt
);
4264 VEC_free (gimple
, heap
, to_remove
);
4269 /* Borrow a bit of tree-ssa-dce.c for the moment.
4270 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4271 this may be a bit faster, and we may want critical edges kept split. */
4273 /* If OP's defining statement has not already been determined to be necessary,
4274 mark that statement necessary. Return the stmt, if it is newly
4277 static inline gimple
4278 mark_operand_necessary (tree op
)
4284 if (TREE_CODE (op
) != SSA_NAME
)
4287 stmt
= SSA_NAME_DEF_STMT (op
);
4290 if (gimple_plf (stmt
, NECESSARY
)
4291 || gimple_nop_p (stmt
))
4294 gimple_set_plf (stmt
, NECESSARY
, true);
4298 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4299 to insert PHI nodes sometimes, and because value numbering of casts isn't
4300 perfect, we sometimes end up inserting dead code. This simple DCE-like
4301 pass removes any insertions we made that weren't actually used. */
4304 remove_dead_inserted_code (void)
4306 VEC(gimple
,heap
) *worklist
= NULL
;
4310 worklist
= VEC_alloc (gimple
, heap
, VEC_length (gimple
, inserted_exprs
));
4311 for (i
= 0; VEC_iterate (gimple
, inserted_exprs
, i
, t
); i
++)
4313 if (gimple_plf (t
, NECESSARY
))
4314 VEC_quick_push (gimple
, worklist
, t
);
4316 while (VEC_length (gimple
, worklist
) > 0)
4318 t
= VEC_pop (gimple
, worklist
);
4320 /* PHI nodes are somewhat special in that each PHI alternative has
4321 data and control dependencies. All the statements feeding the
4322 PHI node's arguments are always necessary. */
4323 if (gimple_code (t
) == GIMPLE_PHI
)
4327 VEC_reserve (gimple
, heap
, worklist
, gimple_phi_num_args (t
));
4328 for (k
= 0; k
< gimple_phi_num_args (t
); k
++)
4330 tree arg
= PHI_ARG_DEF (t
, k
);
4331 if (TREE_CODE (arg
) == SSA_NAME
)
4333 gimple n
= mark_operand_necessary (arg
);
4335 VEC_quick_push (gimple
, worklist
, n
);
4341 /* Propagate through the operands. Examine all the USE, VUSE and
4342 VDEF operands in this statement. Mark all the statements
4343 which feed this statement's uses as necessary. */
4347 /* The operands of VDEF expressions are also needed as they
4348 represent potential definitions that may reach this
4349 statement (VDEF operands allow us to follow def-def
4352 FOR_EACH_SSA_TREE_OPERAND (use
, t
, iter
, SSA_OP_ALL_USES
)
4354 gimple n
= mark_operand_necessary (use
);
4356 VEC_safe_push (gimple
, heap
, worklist
, n
);
4361 for (i
= 0; VEC_iterate (gimple
, inserted_exprs
, i
, t
); i
++)
4363 if (!gimple_plf (t
, NECESSARY
))
4365 gimple_stmt_iterator gsi
;
4367 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4369 fprintf (dump_file
, "Removing unnecessary insertion:");
4370 print_gimple_stmt (dump_file
, t
, 0, 0);
4373 gsi
= gsi_for_stmt (t
);
4374 if (gimple_code (t
) == GIMPLE_PHI
)
4375 remove_phi_node (&gsi
, true);
4377 gsi_remove (&gsi
, true);
4381 VEC_free (gimple
, heap
, worklist
);
4384 /* Initialize data structures used by PRE. */
4387 init_pre (bool do_fre
)
4391 next_expression_id
= 1;
4393 VEC_safe_push (pre_expr
, heap
, expressions
, NULL
);
4394 value_expressions
= VEC_alloc (bitmap_set_t
, heap
, get_max_value_id () + 1);
4395 VEC_safe_grow_cleared (bitmap_set_t
, heap
, value_expressions
,
4396 get_max_value_id() + 1);
4400 inserted_exprs
= NULL
;
4401 need_creation
= NULL
;
4402 pretemp
= NULL_TREE
;
4403 storetemp
= NULL_TREE
;
4404 prephitemp
= NULL_TREE
;
4406 connect_infinite_loops_to_exit ();
4407 memset (&pre_stats
, 0, sizeof (pre_stats
));
4410 postorder
= XNEWVEC (int, n_basic_blocks
- NUM_FIXED_BLOCKS
);
4411 post_order_compute (postorder
, false, false);
4414 bb
->aux
= XCNEWVEC (struct bb_bitmap_sets
, 1);
4416 calculate_dominance_info (CDI_POST_DOMINATORS
);
4417 calculate_dominance_info (CDI_DOMINATORS
);
4419 bitmap_obstack_initialize (&grand_bitmap_obstack
);
4420 inserted_phi_names
= BITMAP_ALLOC (&grand_bitmap_obstack
);
4421 phi_translate_table
= htab_create (5110, expr_pred_trans_hash
,
4422 expr_pred_trans_eq
, free
);
4423 expression_to_id
= htab_create (num_ssa_names
* 3,
4426 seen_during_translate
= BITMAP_ALLOC (&grand_bitmap_obstack
);
4427 bitmap_set_pool
= create_alloc_pool ("Bitmap sets",
4428 sizeof (struct bitmap_set
), 30);
4429 pre_expr_pool
= create_alloc_pool ("pre_expr nodes",
4430 sizeof (struct pre_expr_d
), 30);
4433 EXP_GEN (bb
) = bitmap_set_new ();
4434 PHI_GEN (bb
) = bitmap_set_new ();
4435 TMP_GEN (bb
) = bitmap_set_new ();
4436 AVAIL_OUT (bb
) = bitmap_set_new ();
4438 maximal_set
= in_fre
? NULL
: bitmap_set_new ();
4440 need_eh_cleanup
= BITMAP_ALLOC (NULL
);
4444 /* Deallocate data structures used by PRE. */
4447 fini_pre (bool do_fre
)
4452 VEC_free (bitmap_set_t
, heap
, value_expressions
);
4453 VEC_free (gimple
, heap
, inserted_exprs
);
4454 VEC_free (gimple
, heap
, need_creation
);
4455 bitmap_obstack_release (&grand_bitmap_obstack
);
4456 free_alloc_pool (bitmap_set_pool
);
4457 free_alloc_pool (pre_expr_pool
);
4458 htab_delete (phi_translate_table
);
4459 htab_delete (expression_to_id
);
4467 free_dominance_info (CDI_POST_DOMINATORS
);
4469 if (!bitmap_empty_p (need_eh_cleanup
))
4471 gimple_purge_all_dead_eh_edges (need_eh_cleanup
);
4472 cleanup_tree_cfg ();
4475 BITMAP_FREE (need_eh_cleanup
);
4478 loop_optimizer_finalize ();
4481 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4482 only wants to do full redundancy elimination. */
4485 execute_pre (bool do_fre ATTRIBUTE_UNUSED
)
4487 unsigned int todo
= 0;
4489 do_partial_partial
= optimize
> 2;
4491 /* This has to happen before SCCVN runs because
4492 loop_optimizer_init may create new phis, etc. */
4494 loop_optimizer_init (LOOPS_NORMAL
);
4496 if (!run_scc_vn (do_fre
))
4500 remove_dead_inserted_code ();
4501 loop_optimizer_finalize ();
4509 /* Collect and value number expressions computed in each basic block. */
4512 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4518 print_bitmap_set (dump_file
, EXP_GEN (bb
), "exp_gen", bb
->index
);
4519 print_bitmap_set (dump_file
, PHI_GEN (bb
), "phi_gen", bb
->index
);
4520 print_bitmap_set (dump_file
, TMP_GEN (bb
), "tmp_gen", bb
->index
);
4521 print_bitmap_set (dump_file
, AVAIL_OUT (bb
), "avail_out", bb
->index
);
4524 print_bitmap_set (dump_file
, maximal_set
, "maximal", 0);
4527 /* Insert can get quite slow on an incredibly large number of basic
4528 blocks due to some quadratic behavior. Until this behavior is
4529 fixed, don't run it when he have an incredibly large number of
4530 bb's. If we aren't going to run insert, there is no point in
4531 computing ANTIC, either, even though it's plenty fast. */
4532 if (!do_fre
&& n_basic_blocks
< 4000)
4538 /* Remove all the redundant expressions. */
4539 todo
|= eliminate ();
4541 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4542 statistics_counter_event (cfun
, "PA inserted", pre_stats
.pa_insert
);
4543 statistics_counter_event (cfun
, "New PHIs", pre_stats
.phis
);
4544 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4545 statistics_counter_event (cfun
, "Constified", pre_stats
.constified
);
4547 /* Make sure to remove fake edges before committing our inserts.
4548 This makes sure we don't end up with extra critical edges that
4549 we would need to split. */
4550 remove_fake_exit_edges ();
4551 gsi_commit_edge_inserts ();
4553 clear_expression_ids ();
4556 remove_dead_inserted_code ();
4563 /* Gate and execute functions for PRE. */
4568 return execute_pre (false);
4574 /* PRE tends to generate bigger code. */
4575 return flag_tree_pre
!= 0 && optimize_function_for_speed_p (cfun
);
4578 struct gimple_opt_pass pass_pre
=
4583 gate_pre
, /* gate */
4584 do_pre
, /* execute */
4587 0, /* static_pass_number */
4588 TV_TREE_PRE
, /* tv_id */
4589 PROP_no_crit_edges
| PROP_cfg
4590 | PROP_ssa
, /* properties_required */
4591 0, /* properties_provided */
4592 0, /* properties_destroyed */
4593 TODO_rebuild_alias
, /* todo_flags_start */
4594 TODO_update_ssa_only_virtuals
| TODO_dump_func
| TODO_ggc_collect
4595 | TODO_verify_ssa
/* todo_flags_finish */
4600 /* Gate and execute functions for FRE. */
4605 return execute_pre (true);
4611 return flag_tree_fre
!= 0;
4614 struct gimple_opt_pass pass_fre
=
4619 gate_fre
, /* gate */
4620 execute_fre
, /* execute */
4623 0, /* static_pass_number */
4624 TV_TREE_FRE
, /* tv_id */
4625 PROP_cfg
| PROP_ssa
, /* properties_required */
4626 0, /* properties_provided */
4627 0, /* properties_destroyed */
4628 0, /* todo_flags_start */
4629 TODO_dump_func
| TODO_ggc_collect
| TODO_verify_ssa
/* todo_flags_finish */