2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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"
28 #include "basic-block.h"
29 #include "diagnostic.h"
30 #include "tree-inline.h"
31 #include "tree-flow.h"
33 #include "tree-dump.h"
37 #include "tree-iterator.h"
38 #include "alloc-pool.h"
40 #include "tree-pass.h"
43 #include "langhooks.h"
45 #include "tree-ssa-sccvn.h"
46 #include "tree-scalar-evolution.h"
52 1. Avail sets can be shared by making an avail_find_leader that
53 walks up the dominator tree and looks in those avail sets.
54 This might affect code optimality, it's unclear right now.
55 2. Strength reduction can be performed by anticipating expressions
56 we can repair later on.
57 3. We can do back-substitution or smarter value numbering to catch
58 commutative expressions split up over multiple statements.
61 /* For ease of terminology, "expression node" in the below refers to
62 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
63 represent the actual statement containing the expressions we care about,
64 and we cache the value number by putting it in the expression. */
68 First we walk the statements to generate the AVAIL sets, the
69 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
70 generation of values/expressions by a given block. We use them
71 when computing the ANTIC sets. The AVAIL sets consist of
72 SSA_NAME's that represent values, so we know what values are
73 available in what blocks. AVAIL is a forward dataflow problem. In
74 SSA, values are never killed, so we don't need a kill set, or a
75 fixpoint iteration, in order to calculate the AVAIL sets. In
76 traditional parlance, AVAIL sets tell us the downsafety of the
79 Next, we generate the ANTIC sets. These sets represent the
80 anticipatable expressions. ANTIC is a backwards dataflow
81 problem. An expression is anticipatable in a given block if it could
82 be generated in that block. This means that if we had to perform
83 an insertion in that block, of the value of that expression, we
84 could. Calculating the ANTIC sets requires phi translation of
85 expressions, because the flow goes backwards through phis. We must
86 iterate to a fixpoint of the ANTIC sets, because we have a kill
87 set. Even in SSA form, values are not live over the entire
88 function, only from their definition point onwards. So we have to
89 remove values from the ANTIC set once we go past the definition
90 point of the leaders that make them up.
91 compute_antic/compute_antic_aux performs this computation.
93 Third, we perform insertions to make partially redundant
94 expressions fully redundant.
96 An expression is partially redundant (excluding partial
99 1. It is AVAIL in some, but not all, of the predecessors of a
101 2. It is ANTIC in all the predecessors.
103 In order to make it fully redundant, we insert the expression into
104 the predecessors where it is not available, but is ANTIC.
106 For the partial anticipation case, we only perform insertion if it
107 is partially anticipated in some block, and fully available in all
110 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
111 performs these steps.
113 Fourth, we eliminate fully redundant expressions.
114 This is a simple statement walk that replaces redundant
115 calculations with the now available values. */
117 /* Representations of value numbers:
119 Value numbers are represented by a representative SSA_NAME. We
120 will create fake SSA_NAME's in situations where we need a
121 representative but do not have one (because it is a complex
122 expression). In order to facilitate storing the value numbers in
123 bitmaps, and keep the number of wasted SSA_NAME's down, we also
124 associate a value_id with each value number, and create full blown
125 ssa_name's only where we actually need them (IE in operands of
126 existing expressions).
128 Theoretically you could replace all the value_id's with
129 SSA_NAME_VERSION, but this would allocate a large number of
130 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
131 It would also require an additional indirection at each point we
134 /* Representation of expressions on value numbers:
136 Expressions consisting of value numbers are represented the same
137 way as our VN internally represents them, with an additional
138 "pre_expr" wrapping around them in order to facilitate storing all
139 of the expressions in the same sets. */
141 /* Representation of sets:
143 The dataflow sets do not need to be sorted in any particular order
144 for the majority of their lifetime, are simply represented as two
145 bitmaps, one that keeps track of values present in the set, and one
146 that keeps track of expressions present in the set.
148 When we need them in topological order, we produce it on demand by
149 transforming the bitmap into an array and sorting it into topo
152 /* Type of expression, used to know which member of the PRE_EXPR union
163 typedef union pre_expr_union_d
168 vn_reference_t reference;
171 typedef struct pre_expr_d
173 enum pre_expr_kind kind;
178 #define PRE_EXPR_NAME(e) (e)->u.name
179 #define PRE_EXPR_NARY(e) (e)->u.nary
180 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
181 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
184 pre_expr_eq (const void *p1, const void *p2)
186 const struct pre_expr_d *e1 = (const struct pre_expr_d *) p1;
187 const struct pre_expr_d *e2 = (const struct pre_expr_d *) p2;
189 if (e1->kind != e2->kind)
195 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
196 PRE_EXPR_CONSTANT (e2));
198 return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
200 return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
202 return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
203 PRE_EXPR_REFERENCE (e2));
210 pre_expr_hash (const void *p1)
212 const struct pre_expr_d *e = (const struct pre_expr_d *) p1;
216 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
218 return SSA_NAME_VERSION (PRE_EXPR_NAME (e));
220 return PRE_EXPR_NARY (e)->hashcode;
222 return PRE_EXPR_REFERENCE (e)->hashcode;
229 /* Next global expression id number. */
230 static unsigned int next_expression_id;
232 /* Mapping from expression to id number we can use in bitmap sets. */
233 DEF_VEC_P (pre_expr);
234 DEF_VEC_ALLOC_P (pre_expr, heap);
235 static VEC(pre_expr, heap) *expressions;
236 static htab_t expression_to_id;
237 static VEC(unsigned, heap) *name_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 if (expr->kind == NAME)
251 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
252 /* VEC_safe_grow_cleared allocates no headroom. Avoid frequent
253 re-allocations by using VEC_reserve upfront. There is no
254 VEC_quick_grow_cleared unfortunately. */
255 VEC_reserve (unsigned, heap, name_to_id, num_ssa_names);
256 VEC_safe_grow_cleared (unsigned, heap, name_to_id, num_ssa_names);
257 gcc_assert (VEC_index (unsigned, name_to_id, version) == 0);
258 VEC_replace (unsigned, name_to_id, version, expr->id);
262 slot = htab_find_slot (expression_to_id, expr, INSERT);
266 return next_expression_id - 1;
269 /* Return the expression id for tree EXPR. */
271 static inline unsigned int
272 get_expression_id (const pre_expr expr)
277 static inline unsigned int
278 lookup_expression_id (const pre_expr expr)
282 if (expr->kind == NAME)
284 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
285 if (VEC_length (unsigned, name_to_id) <= version)
287 return VEC_index (unsigned, name_to_id, version);
291 slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
294 return ((pre_expr)*slot)->id;
298 /* Return the existing expression id for EXPR, or create one if one
299 does not exist yet. */
301 static inline unsigned int
302 get_or_alloc_expression_id (pre_expr expr)
304 unsigned int id = lookup_expression_id (expr);
306 return alloc_expression_id (expr);
307 return expr->id = id;
310 /* Return the expression that has expression id ID */
312 static inline pre_expr
313 expression_for_id (unsigned int id)
315 return VEC_index (pre_expr, expressions, id);
318 /* Free the expression id field in all of our expressions,
319 and then destroy the expressions array. */
322 clear_expression_ids (void)
324 VEC_free (pre_expr, heap, expressions);
327 static alloc_pool pre_expr_pool;
329 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
332 get_or_alloc_expr_for_name (tree name)
334 struct pre_expr_d expr;
336 unsigned int result_id;
340 PRE_EXPR_NAME (&expr) = name;
341 result_id = lookup_expression_id (&expr);
343 return expression_for_id (result_id);
345 result = (pre_expr) pool_alloc (pre_expr_pool);
347 PRE_EXPR_NAME (result) = name;
348 alloc_expression_id (result);
352 static bool in_fre = false;
354 /* An unordered bitmap set. One bitmap tracks values, the other,
356 typedef struct bitmap_set
362 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
363 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
365 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
366 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
368 /* Mapping from value id to expressions with that value_id. */
369 DEF_VEC_P (bitmap_set_t);
370 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
371 static VEC(bitmap_set_t, heap) *value_expressions;
373 /* Sets that we need to keep track of. */
374 typedef struct bb_bitmap_sets
376 /* The EXP_GEN set, which represents expressions/values generated in
378 bitmap_set_t exp_gen;
380 /* The PHI_GEN set, which represents PHI results generated in a
382 bitmap_set_t phi_gen;
384 /* The TMP_GEN set, which represents results/temporaries generated
385 in a basic block. IE the LHS of an expression. */
386 bitmap_set_t tmp_gen;
388 /* The AVAIL_OUT set, which represents which values are available in
389 a given basic block. */
390 bitmap_set_t avail_out;
392 /* The ANTIC_IN set, which represents which values are anticipatable
393 in a given basic block. */
394 bitmap_set_t antic_in;
396 /* The PA_IN set, which represents which values are
397 partially anticipatable in a given basic block. */
400 /* The NEW_SETS set, which is used during insertion to augment the
401 AVAIL_OUT set of blocks with the new insertions performed during
402 the current iteration. */
403 bitmap_set_t new_sets;
405 /* A cache for value_dies_in_block_x. */
408 /* True if we have visited this block during ANTIC calculation. */
409 unsigned int visited : 1;
411 /* True we have deferred processing this block during ANTIC
412 calculation until its successor is processed. */
413 unsigned int deferred : 1;
415 /* True when the block contains a call that might not return. */
416 unsigned int contains_may_not_return_call : 1;
419 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
420 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
421 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
422 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
423 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
424 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
425 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
426 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
427 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
428 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
429 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
432 /* Basic block list in postorder. */
433 static int *postorder;
435 /* This structure is used to keep track of statistics on what
436 optimization PRE was able to perform. */
439 /* The number of RHS computations eliminated by PRE. */
442 /* The number of new expressions/temporaries generated by PRE. */
445 /* The number of inserts found due to partial anticipation */
448 /* The number of new PHI nodes added by PRE. */
451 /* The number of values found constant. */
456 static bool do_partial_partial;
457 static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
458 static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
459 static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
460 static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
461 static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
462 static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
463 static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr,
465 static bitmap_set_t bitmap_set_new (void);
466 static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
468 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
470 static unsigned int get_expr_value_id (pre_expr);
472 /* We can add and remove elements and entries to and from sets
473 and hash tables, so we use alloc pools for them. */
475 static alloc_pool bitmap_set_pool;
476 static bitmap_obstack grand_bitmap_obstack;
478 /* To avoid adding 300 temporary variables when we only need one, we
479 only create one temporary variable, on demand, and build ssa names
480 off that. We do have to change the variable if the types don't
481 match the current variable's type. */
483 static tree storetemp;
484 static tree prephitemp;
486 /* Set of blocks with statements that have had its EH information
488 static bitmap need_eh_cleanup;
490 /* The phi_translate_table caches phi translations for a given
491 expression and predecessor. */
493 static htab_t phi_translate_table;
495 /* A three tuple {e, pred, v} used to cache phi translations in the
496 phi_translate_table. */
498 typedef struct expr_pred_trans_d
500 /* The expression. */
503 /* The predecessor block along which we translated the expression. */
506 /* The value that resulted from the translation. */
509 /* The hashcode for the expression, pred pair. This is cached for
512 } *expr_pred_trans_t;
513 typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
515 /* Return the hash value for a phi translation table entry. */
518 expr_pred_trans_hash (const void *p)
520 const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
524 /* Return true if two phi translation table entries are the same.
525 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
528 expr_pred_trans_eq (const void *p1, const void *p2)
530 const_expr_pred_trans_t const ve1 = (const_expr_pred_trans_t) p1;
531 const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
532 basic_block b1 = ve1->pred;
533 basic_block b2 = ve2->pred;
535 /* If they are not translations for the same basic block, they can't
539 return pre_expr_eq (ve1->e, ve2->e);
542 /* Search in the phi translation table for the translation of
543 expression E in basic block PRED.
544 Return the translated value, if found, NULL otherwise. */
546 static inline pre_expr
547 phi_trans_lookup (pre_expr e, basic_block pred)
550 struct expr_pred_trans_d ept;
554 ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
555 slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
560 return ((expr_pred_trans_t) *slot)->v;
564 /* Add the tuple mapping from {expression E, basic block PRED} to
565 value V, to the phi translation table. */
568 phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
571 expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
573 new_pair->pred = pred;
575 new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
578 slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
579 new_pair->hashcode, INSERT);
582 *slot = (void *) new_pair;
586 /* Add expression E to the expression set of value id V. */
589 add_to_value (unsigned int v, pre_expr e)
593 gcc_assert (get_expr_value_id (e) == v);
595 if (v >= VEC_length (bitmap_set_t, value_expressions))
597 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
601 set = VEC_index (bitmap_set_t, value_expressions, v);
604 set = bitmap_set_new ();
605 VEC_replace (bitmap_set_t, value_expressions, v, set);
608 bitmap_insert_into_set_1 (set, e, v, true);
611 /* Create a new bitmap set and return it. */
614 bitmap_set_new (void)
616 bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
617 ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
618 ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
622 /* Return the value id for a PRE expression EXPR. */
625 get_expr_value_id (pre_expr expr)
632 id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
635 id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
636 add_to_value (id, expr);
641 return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
643 return PRE_EXPR_NARY (expr)->value_id;
645 return PRE_EXPR_REFERENCE (expr)->value_id;
651 /* Remove an expression EXPR from a bitmapped set. */
654 bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
656 unsigned int val = get_expr_value_id (expr);
657 if (!value_id_constant_p (val))
659 bitmap_clear_bit (set->values, val);
660 bitmap_clear_bit (set->expressions, get_expression_id (expr));
665 bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
666 unsigned int val, bool allow_constants)
668 if (allow_constants || !value_id_constant_p (val))
670 /* We specifically expect this and only this function to be able to
671 insert constants into a set. */
672 bitmap_set_bit (set->values, val);
673 bitmap_set_bit (set->expressions, get_or_alloc_expression_id (expr));
677 /* Insert an expression EXPR into a bitmapped set. */
680 bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
682 bitmap_insert_into_set_1 (set, expr, get_expr_value_id (expr), false);
685 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
688 bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
690 bitmap_copy (dest->expressions, orig->expressions);
691 bitmap_copy (dest->values, orig->values);
695 /* Free memory used up by SET. */
697 bitmap_set_free (bitmap_set_t set)
699 BITMAP_FREE (set->expressions);
700 BITMAP_FREE (set->values);
704 /* Generate an topological-ordered array of bitmap set SET. */
706 static VEC(pre_expr, heap) *
707 sorted_array_from_bitmap_set (bitmap_set_t set)
710 bitmap_iterator bi, bj;
711 VEC(pre_expr, heap) *result;
713 /* Pre-allocate roughly enough space for the array. */
714 result = VEC_alloc (pre_expr, heap, bitmap_count_bits (set->values));
716 FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
718 /* The number of expressions having a given value is usually
719 relatively small. Thus, rather than making a vector of all
720 the expressions and sorting it by value-id, we walk the values
721 and check in the reverse mapping that tells us what expressions
722 have a given value, to filter those in our set. As a result,
723 the expressions are inserted in value-id order, which means
726 If this is somehow a significant lose for some cases, we can
727 choose which set to walk based on the set size. */
728 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
729 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
731 if (bitmap_bit_p (set->expressions, j))
732 VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
739 /* Perform bitmapped set operation DEST &= ORIG. */
742 bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
749 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
751 bitmap_and_into (dest->values, orig->values);
752 bitmap_copy (temp, dest->expressions);
753 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
755 pre_expr expr = expression_for_id (i);
756 unsigned int value_id = get_expr_value_id (expr);
757 if (!bitmap_bit_p (dest->values, value_id))
758 bitmap_clear_bit (dest->expressions, i);
764 /* Subtract all values and expressions contained in ORIG from DEST. */
767 bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
769 bitmap_set_t result = bitmap_set_new ();
773 bitmap_and_compl (result->expressions, dest->expressions,
776 FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
778 pre_expr expr = expression_for_id (i);
779 unsigned int value_id = get_expr_value_id (expr);
780 bitmap_set_bit (result->values, value_id);
786 /* Subtract all the values in bitmap set B from bitmap set A. */
789 bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
793 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
795 bitmap_copy (temp, a->expressions);
796 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
798 pre_expr expr = expression_for_id (i);
799 if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
800 bitmap_remove_from_set (a, expr);
806 /* Return true if bitmapped set SET contains the value VALUE_ID. */
809 bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
811 if (value_id_constant_p (value_id))
814 if (!set || bitmap_empty_p (set->expressions))
817 return bitmap_bit_p (set->values, value_id);
821 bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
823 return bitmap_bit_p (set->expressions, get_expression_id (expr));
826 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
829 bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
832 bitmap_set_t exprset;
836 if (value_id_constant_p (lookfor))
839 if (!bitmap_set_contains_value (set, lookfor))
842 /* The number of expressions having a given value is usually
843 significantly less than the total number of expressions in SET.
844 Thus, rather than check, for each expression in SET, whether it
845 has the value LOOKFOR, we walk the reverse mapping that tells us
846 what expressions have a given value, and see if any of those
847 expressions are in our set. For large testcases, this is about
848 5-10x faster than walking the bitmap. If this is somehow a
849 significant lose for some cases, we can choose which set to walk
850 based on the set size. */
851 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
852 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
854 if (bitmap_bit_p (set->expressions, i))
856 bitmap_clear_bit (set->expressions, i);
857 bitmap_set_bit (set->expressions, get_expression_id (expr));
863 /* Return true if two bitmap sets are equal. */
866 bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
868 return bitmap_equal_p (a->values, b->values);
871 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
872 and add it otherwise. */
875 bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
877 unsigned int val = get_expr_value_id (expr);
879 if (bitmap_set_contains_value (set, val))
880 bitmap_set_replace_value (set, val, expr);
882 bitmap_insert_into_set (set, expr);
885 /* Insert EXPR into SET if EXPR's value is not already present in
889 bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
891 unsigned int val = get_expr_value_id (expr);
893 #ifdef ENABLE_CHECKING
894 gcc_assert (expr->id == get_or_alloc_expression_id (expr));
897 /* Constant values are always considered to be part of the set. */
898 if (value_id_constant_p (val))
901 /* If the value membership changed, add the expression. */
902 if (bitmap_set_bit (set->values, val))
903 bitmap_set_bit (set->expressions, expr->id);
906 /* Print out EXPR to outfile. */
909 print_pre_expr (FILE *outfile, const pre_expr expr)
914 print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
917 print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
922 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
923 fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
924 for (i = 0; i < nary->length; i++)
926 print_generic_expr (outfile, nary->op[i], 0);
927 if (i != (unsigned) nary->length - 1)
928 fprintf (outfile, ",");
930 fprintf (outfile, "}");
936 vn_reference_op_t vro;
938 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
939 fprintf (outfile, "{");
941 VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
944 bool closebrace = false;
945 if (vro->opcode != SSA_NAME
946 && TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
948 fprintf (outfile, "%s", tree_code_name [vro->opcode]);
951 fprintf (outfile, "<");
957 print_generic_expr (outfile, vro->op0, 0);
960 fprintf (outfile, ",");
961 print_generic_expr (outfile, vro->op1, 0);
965 fprintf (outfile, ",");
966 print_generic_expr (outfile, vro->op2, 0);
970 fprintf (outfile, ">");
971 if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
972 fprintf (outfile, ",");
974 fprintf (outfile, "}");
977 fprintf (outfile, "@");
978 print_generic_expr (outfile, ref->vuse, 0);
984 void debug_pre_expr (pre_expr);
986 /* Like print_pre_expr but always prints to stderr. */
988 debug_pre_expr (pre_expr e)
990 print_pre_expr (stderr, e);
991 fprintf (stderr, "\n");
994 /* Print out SET to OUTFILE. */
997 print_bitmap_set (FILE *outfile, bitmap_set_t set,
998 const char *setname, int blockindex)
1000 fprintf (outfile, "%s[%d] := { ", setname, blockindex);
1007 FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
1009 const pre_expr expr = expression_for_id (i);
1012 fprintf (outfile, ", ");
1014 print_pre_expr (outfile, expr);
1016 fprintf (outfile, " (%04d)", get_expr_value_id (expr));
1019 fprintf (outfile, " }\n");
1022 void debug_bitmap_set (bitmap_set_t);
1025 debug_bitmap_set (bitmap_set_t set)
1027 print_bitmap_set (stderr, set, "debug", 0);
1030 /* Print out the expressions that have VAL to OUTFILE. */
1033 print_value_expressions (FILE *outfile, unsigned int val)
1035 bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
1039 sprintf (s, "%04d", val);
1040 print_bitmap_set (outfile, set, s, 0);
1046 debug_value_expressions (unsigned int val)
1048 print_value_expressions (stderr, val);
1051 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1055 get_or_alloc_expr_for_constant (tree constant)
1057 unsigned int result_id;
1058 unsigned int value_id;
1059 struct pre_expr_d expr;
1062 expr.kind = CONSTANT;
1063 PRE_EXPR_CONSTANT (&expr) = constant;
1064 result_id = lookup_expression_id (&expr);
1066 return expression_for_id (result_id);
1068 newexpr = (pre_expr) pool_alloc (pre_expr_pool);
1069 newexpr->kind = CONSTANT;
1070 PRE_EXPR_CONSTANT (newexpr) = constant;
1071 alloc_expression_id (newexpr);
1072 value_id = get_or_alloc_constant_value_id (constant);
1073 add_to_value (value_id, newexpr);
1077 /* Given a value id V, find the actual tree representing the constant
1078 value if there is one, and return it. Return NULL if we can't find
1082 get_constant_for_value_id (unsigned int v)
1084 if (value_id_constant_p (v))
1088 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
1090 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1092 pre_expr expr = expression_for_id (i);
1093 if (expr->kind == CONSTANT)
1094 return PRE_EXPR_CONSTANT (expr);
1100 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1101 Currently only supports constants and SSA_NAMES. */
1103 get_or_alloc_expr_for (tree t)
1105 if (TREE_CODE (t) == SSA_NAME)
1106 return get_or_alloc_expr_for_name (t);
1107 else if (is_gimple_min_invariant (t))
1108 return get_or_alloc_expr_for_constant (t);
1111 /* More complex expressions can result from SCCVN expression
1112 simplification that inserts values for them. As they all
1113 do not have VOPs the get handled by the nary ops struct. */
1114 vn_nary_op_t result;
1115 unsigned int result_id;
1116 vn_nary_op_lookup (t, &result);
1119 pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
1121 PRE_EXPR_NARY (e) = result;
1122 result_id = lookup_expression_id (e);
1125 pool_free (pre_expr_pool, e);
1126 e = expression_for_id (result_id);
1129 alloc_expression_id (e);
1136 /* Return the folded version of T if T, when folded, is a gimple
1137 min_invariant. Otherwise, return T. */
1140 fully_constant_expression (pre_expr e)
1148 vn_nary_op_t nary = PRE_EXPR_NARY (e);
1149 switch (TREE_CODE_CLASS (nary->opcode))
1151 case tcc_expression:
1152 if (nary->opcode == TRUTH_NOT_EXPR)
1154 if (nary->opcode != TRUTH_AND_EXPR
1155 && nary->opcode != TRUTH_OR_EXPR
1156 && nary->opcode != TRUTH_XOR_EXPR)
1160 case tcc_comparison:
1162 /* We have to go from trees to pre exprs to value ids to
1164 tree naryop0 = nary->op[0];
1165 tree naryop1 = nary->op[1];
1167 if (!is_gimple_min_invariant (naryop0))
1169 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1170 unsigned int vrep0 = get_expr_value_id (rep0);
1171 tree const0 = get_constant_for_value_id (vrep0);
1173 naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
1175 if (!is_gimple_min_invariant (naryop1))
1177 pre_expr rep1 = get_or_alloc_expr_for (naryop1);
1178 unsigned int vrep1 = get_expr_value_id (rep1);
1179 tree const1 = get_constant_for_value_id (vrep1);
1181 naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
1183 result = fold_binary (nary->opcode, nary->type,
1185 if (result && is_gimple_min_invariant (result))
1186 return get_or_alloc_expr_for_constant (result);
1187 /* We might have simplified the expression to a
1188 SSA_NAME for example from x_1 * 1. But we cannot
1189 insert a PHI for x_1 unconditionally as x_1 might
1190 not be available readily. */
1194 if (nary->opcode != REALPART_EXPR
1195 && nary->opcode != IMAGPART_EXPR
1196 && nary->opcode != VIEW_CONVERT_EXPR)
1202 /* We have to go from trees to pre exprs to value ids to
1204 tree naryop0 = nary->op[0];
1205 tree const0, result;
1206 if (is_gimple_min_invariant (naryop0))
1210 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1211 unsigned int vrep0 = get_expr_value_id (rep0);
1212 const0 = get_constant_for_value_id (vrep0);
1217 tree type1 = TREE_TYPE (nary->op[0]);
1218 const0 = fold_convert (type1, const0);
1219 result = fold_unary (nary->opcode, nary->type, const0);
1221 if (result && is_gimple_min_invariant (result))
1222 return get_or_alloc_expr_for_constant (result);
1231 vn_reference_t ref = PRE_EXPR_REFERENCE (e);
1233 if ((folded = fully_constant_vn_reference_p (ref)))
1234 return get_or_alloc_expr_for_constant (folded);
1243 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1244 it has the value it would have in BLOCK. Set *SAME_VALID to true
1245 in case the new vuse doesn't change the value id of the OPERANDS. */
1248 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
1249 alias_set_type set, tree type, tree vuse,
1250 basic_block phiblock,
1251 basic_block block, bool *same_valid)
1253 gimple phi = SSA_NAME_DEF_STMT (vuse);
1260 if (gimple_bb (phi) != phiblock)
1263 use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);
1265 /* Use the alias-oracle to find either the PHI node in this block,
1266 the first VUSE used in this block that is equivalent to vuse or
1267 the first VUSE which definition in this block kills the value. */
1268 if (gimple_code (phi) == GIMPLE_PHI)
1269 e = find_edge (block, phiblock);
1270 else if (use_oracle)
1271 while (!stmt_may_clobber_ref_p_1 (phi, &ref))
1273 vuse = gimple_vuse (phi);
1274 phi = SSA_NAME_DEF_STMT (vuse);
1275 if (gimple_bb (phi) != phiblock)
1277 if (gimple_code (phi) == GIMPLE_PHI)
1279 e = find_edge (block, phiblock);
1290 bitmap visited = NULL;
1291 /* Try to find a vuse that dominates this phi node by skipping
1292 non-clobbering statements. */
1293 vuse = get_continuation_for_phi (phi, &ref, &visited);
1295 BITMAP_FREE (visited);
1301 /* If we didn't find any, the value ID can't stay the same,
1302 but return the translated vuse. */
1303 *same_valid = false;
1304 vuse = PHI_ARG_DEF (phi, e->dest_idx);
1306 /* ??? We would like to return vuse here as this is the canonical
1307 upmost vdef that this reference is associated with. But during
1308 insertion of the references into the hash tables we only ever
1309 directly insert with their direct gimple_vuse, hence returning
1310 something else would make us not find the other expression. */
1311 return PHI_ARG_DEF (phi, e->dest_idx);
1317 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1318 SET2. This is used to avoid making a set consisting of the union
1319 of PA_IN and ANTIC_IN during insert. */
1321 static inline pre_expr
1322 find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
1326 result = bitmap_find_leader (set1, val, NULL);
1327 if (!result && set2)
1328 result = bitmap_find_leader (set2, val, NULL);
1332 /* Get the tree type for our PRE expression e. */
1335 get_expr_type (const pre_expr e)
1340 return TREE_TYPE (PRE_EXPR_NAME (e));
1342 return TREE_TYPE (PRE_EXPR_CONSTANT (e));
1344 return PRE_EXPR_REFERENCE (e)->type;
1346 return PRE_EXPR_NARY (e)->type;
1351 /* Get a representative SSA_NAME for a given expression.
1352 Since all of our sub-expressions are treated as values, we require
1353 them to be SSA_NAME's for simplicity.
1354 Prior versions of GVNPRE used to use "value handles" here, so that
1355 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1356 either case, the operands are really values (IE we do not expect
1357 them to be usable without finding leaders). */
1360 get_representative_for (const pre_expr e)
1364 unsigned int value_id = get_expr_value_id (e);
1369 return PRE_EXPR_NAME (e);
1371 return PRE_EXPR_CONSTANT (e);
1375 /* Go through all of the expressions representing this value
1376 and pick out an SSA_NAME. */
1379 bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
1381 FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
1383 pre_expr rep = expression_for_id (i);
1384 if (rep->kind == NAME)
1385 return PRE_EXPR_NAME (rep);
1390 /* If we reached here we couldn't find an SSA_NAME. This can
1391 happen when we've discovered a value that has never appeared in
1392 the program as set to an SSA_NAME, most likely as the result of
1397 "Could not find SSA_NAME representative for expression:");
1398 print_pre_expr (dump_file, e);
1399 fprintf (dump_file, "\n");
1402 exprtype = get_expr_type (e);
1404 /* Build and insert the assignment of the end result to the temporary
1405 that we will return. */
1406 if (!pretemp || exprtype != TREE_TYPE (pretemp))
1408 pretemp = create_tmp_reg (exprtype, "pretmp");
1409 get_var_ann (pretemp);
1412 name = make_ssa_name (pretemp, gimple_build_nop ());
1413 VN_INFO_GET (name)->value_id = value_id;
1414 if (e->kind == CONSTANT)
1415 VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
1417 VN_INFO (name)->valnum = name;
1419 add_to_value (value_id, get_or_alloc_expr_for_name (name));
1422 fprintf (dump_file, "Created SSA_NAME representative ");
1423 print_generic_expr (dump_file, name, 0);
1424 fprintf (dump_file, " for expression:");
1425 print_pre_expr (dump_file, e);
1426 fprintf (dump_file, "\n");
1435 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1436 basic_block pred, basic_block phiblock);
1438 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1439 the phis in PRED. Return NULL if we can't find a leader for each part
1440 of the translated expression. */
1443 phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1444 basic_block pred, basic_block phiblock)
1451 bool changed = false;
1452 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
1453 struct vn_nary_op_s newnary;
1454 /* The NARY structure is only guaranteed to have been
1455 allocated to the nary->length operands. */
1456 memcpy (&newnary, nary, (sizeof (struct vn_nary_op_s)
1457 - sizeof (tree) * (4 - nary->length)));
1459 for (i = 0; i < newnary.length; i++)
1461 if (TREE_CODE (newnary.op[i]) != SSA_NAME)
1465 pre_expr leader, result;
1466 unsigned int op_val_id = VN_INFO (newnary.op[i])->value_id;
1467 leader = find_leader_in_sets (op_val_id, set1, set2);
1468 result = phi_translate (leader, set1, set2, pred, phiblock);
1469 if (result && result != leader)
1471 tree name = get_representative_for (result);
1474 newnary.op[i] = name;
1479 changed |= newnary.op[i] != nary->op[i];
1485 unsigned int new_val_id;
1487 tree result = vn_nary_op_lookup_pieces (newnary.length,
1495 if (result && is_gimple_min_invariant (result))
1496 return get_or_alloc_expr_for_constant (result);
1498 expr = (pre_expr) pool_alloc (pre_expr_pool);
1503 PRE_EXPR_NARY (expr) = nary;
1504 constant = fully_constant_expression (expr);
1505 if (constant != expr)
1508 new_val_id = nary->value_id;
1509 get_or_alloc_expression_id (expr);
1513 new_val_id = get_next_value_id ();
1514 VEC_safe_grow_cleared (bitmap_set_t, heap,
1516 get_max_value_id() + 1);
1517 nary = vn_nary_op_insert_pieces (newnary.length,
1524 result, new_val_id);
1525 PRE_EXPR_NARY (expr) = nary;
1526 constant = fully_constant_expression (expr);
1527 if (constant != expr)
1529 get_or_alloc_expression_id (expr);
1531 add_to_value (new_val_id, expr);
1539 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
1540 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1541 tree vuse = ref->vuse;
1542 tree newvuse = vuse;
1543 VEC (vn_reference_op_s, heap) *newoperands = NULL;
1544 bool changed = false, same_valid = true;
1546 vn_reference_op_t operand;
1547 vn_reference_t newref;
1550 VEC_iterate (vn_reference_op_s, operands, i, operand); i++, j++)
1554 tree oldop0 = operand->op0;
1555 tree oldop1 = operand->op1;
1556 tree oldop2 = operand->op2;
1560 tree type = operand->type;
1561 vn_reference_op_s newop = *operand;
1563 if (op0 && TREE_CODE (op0) == SSA_NAME)
1565 unsigned int op_val_id = VN_INFO (op0)->value_id;
1566 leader = find_leader_in_sets (op_val_id, set1, set2);
1567 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1568 if (opresult && opresult != leader)
1570 tree name = get_representative_for (opresult);
1578 changed |= op0 != oldop0;
1580 if (op1 && TREE_CODE (op1) == SSA_NAME)
1582 unsigned int op_val_id = VN_INFO (op1)->value_id;
1583 leader = find_leader_in_sets (op_val_id, set1, set2);
1584 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1585 if (opresult && opresult != leader)
1587 tree name = get_representative_for (opresult);
1595 /* We can't possibly insert these. */
1596 else if (op1 && !is_gimple_min_invariant (op1))
1598 changed |= op1 != oldop1;
1599 if (op2 && TREE_CODE (op2) == SSA_NAME)
1601 unsigned int op_val_id = VN_INFO (op2)->value_id;
1602 leader = find_leader_in_sets (op_val_id, set1, set2);
1603 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1604 if (opresult && opresult != leader)
1606 tree name = get_representative_for (opresult);
1614 /* We can't possibly insert these. */
1615 else if (op2 && !is_gimple_min_invariant (op2))
1617 changed |= op2 != oldop2;
1620 newoperands = VEC_copy (vn_reference_op_s, heap, operands);
1621 /* We may have changed from an SSA_NAME to a constant */
1622 if (newop.opcode == SSA_NAME && TREE_CODE (op0) != SSA_NAME)
1623 newop.opcode = TREE_CODE (op0);
1628 VEC_replace (vn_reference_op_s, newoperands, j, &newop);
1629 /* If it transforms from an SSA_NAME to an address, fold with
1630 a preceding indirect reference. */
1631 if (j > 0 && op0 && TREE_CODE (op0) == ADDR_EXPR
1632 && VEC_index (vn_reference_op_s,
1633 newoperands, j - 1)->opcode == INDIRECT_REF)
1634 vn_reference_fold_indirect (&newoperands, &j);
1636 if (i != VEC_length (vn_reference_op_s, operands))
1639 VEC_free (vn_reference_op_s, heap, newoperands);
1645 newvuse = translate_vuse_through_block (newoperands,
1646 ref->set, ref->type,
1647 vuse, phiblock, pred,
1649 if (newvuse == NULL_TREE)
1651 VEC_free (vn_reference_op_s, heap, newoperands);
1656 if (changed || newvuse != vuse)
1658 unsigned int new_val_id;
1661 tree result = vn_reference_lookup_pieces (newvuse, ref->set,
1666 VEC_free (vn_reference_op_s, heap, newoperands);
1668 if (result && is_gimple_min_invariant (result))
1670 gcc_assert (!newoperands);
1671 return get_or_alloc_expr_for_constant (result);
1674 expr = (pre_expr) pool_alloc (pre_expr_pool);
1675 expr->kind = REFERENCE;
1680 PRE_EXPR_REFERENCE (expr) = newref;
1681 constant = fully_constant_expression (expr);
1682 if (constant != expr)
1685 new_val_id = newref->value_id;
1686 get_or_alloc_expression_id (expr);
1690 if (changed || !same_valid)
1692 new_val_id = get_next_value_id ();
1693 VEC_safe_grow_cleared (bitmap_set_t, heap,
1695 get_max_value_id() + 1);
1698 new_val_id = ref->value_id;
1699 newref = vn_reference_insert_pieces (newvuse, ref->set,
1702 result, new_val_id);
1704 PRE_EXPR_REFERENCE (expr) = newref;
1705 constant = fully_constant_expression (expr);
1706 if (constant != expr)
1708 get_or_alloc_expression_id (expr);
1710 add_to_value (new_val_id, expr);
1712 VEC_free (vn_reference_op_s, heap, newoperands);
1722 tree name = PRE_EXPR_NAME (expr);
1724 def_stmt = SSA_NAME_DEF_STMT (name);
1725 if (gimple_code (def_stmt) == GIMPLE_PHI
1726 && gimple_bb (def_stmt) == phiblock)
1731 e = find_edge (pred, gimple_bb (phi));
1734 tree def = PHI_ARG_DEF (phi, e->dest_idx);
1737 if (TREE_CODE (def) == SSA_NAME)
1738 def = VN_INFO (def)->valnum;
1740 /* Handle constant. */
1741 if (is_gimple_min_invariant (def))
1742 return get_or_alloc_expr_for_constant (def);
1744 if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
1747 newexpr = get_or_alloc_expr_for_name (def);
1758 /* Wrapper around phi_translate_1 providing caching functionality. */
1761 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1762 basic_block pred, basic_block phiblock)
1769 /* Constants contain no values that need translation. */
1770 if (expr->kind == CONSTANT)
1773 if (value_id_constant_p (get_expr_value_id (expr)))
1776 if (expr->kind != NAME)
1778 phitrans = phi_trans_lookup (expr, pred);
1784 phitrans = phi_translate_1 (expr, set1, set2, pred, phiblock);
1786 /* Don't add empty translations to the cache. Neither add
1787 translations of NAMEs as those are cheap to translate. */
1789 && expr->kind != NAME)
1790 phi_trans_add (expr, phitrans, pred);
1796 /* For each expression in SET, translate the values through phi nodes
1797 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1798 expressions in DEST. */
1801 phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
1802 basic_block phiblock)
1804 VEC (pre_expr, heap) *exprs;
1808 if (gimple_seq_empty_p (phi_nodes (phiblock)))
1810 bitmap_set_copy (dest, set);
1814 exprs = sorted_array_from_bitmap_set (set);
1815 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
1817 pre_expr translated;
1818 translated = phi_translate (expr, set, NULL, pred, phiblock);
1822 /* We might end up with multiple expressions from SET being
1823 translated to the same value. In this case we do not want
1824 to retain the NARY or REFERENCE expression but prefer a NAME
1825 which would be the leader. */
1826 if (translated->kind == NAME)
1827 bitmap_value_replace_in_set (dest, translated);
1829 bitmap_value_insert_into_set (dest, translated);
1831 VEC_free (pre_expr, heap, exprs);
1834 /* Find the leader for a value (i.e., the name representing that
1835 value) in a given set, and return it. If STMT is non-NULL it
1836 makes sure the defining statement for the leader dominates it.
1837 Return NULL if no leader is found. */
1840 bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
1842 if (value_id_constant_p (val))
1846 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1848 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1850 pre_expr expr = expression_for_id (i);
1851 if (expr->kind == CONSTANT)
1855 if (bitmap_set_contains_value (set, val))
1857 /* Rather than walk the entire bitmap of expressions, and see
1858 whether any of them has the value we are looking for, we look
1859 at the reverse mapping, which tells us the set of expressions
1860 that have a given value (IE value->expressions with that
1861 value) and see if any of those expressions are in our set.
1862 The number of expressions per value is usually significantly
1863 less than the number of expressions in the set. In fact, for
1864 large testcases, doing it this way is roughly 5-10x faster
1865 than walking the bitmap.
1866 If this is somehow a significant lose for some cases, we can
1867 choose which set to walk based on which set is smaller. */
1870 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1872 EXECUTE_IF_AND_IN_BITMAP (exprset->expressions,
1873 set->expressions, 0, i, bi)
1875 pre_expr val = expression_for_id (i);
1876 /* At the point where stmt is not null, there should always
1877 be an SSA_NAME first in the list of expressions. */
1880 gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
1881 if (gimple_code (def_stmt) != GIMPLE_PHI
1882 && gimple_bb (def_stmt) == gimple_bb (stmt)
1883 && gimple_uid (def_stmt) >= gimple_uid (stmt))
1892 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1893 BLOCK by seeing if it is not killed in the block. Note that we are
1894 only determining whether there is a store that kills it. Because
1895 of the order in which clean iterates over values, we are guaranteed
1896 that altered operands will have caused us to be eliminated from the
1897 ANTIC_IN set already. */
1900 value_dies_in_block_x (pre_expr expr, basic_block block)
1902 tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
1903 vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
1905 gimple_stmt_iterator gsi;
1906 unsigned id = get_expression_id (expr);
1913 /* Lookup a previously calculated result. */
1914 if (EXPR_DIES (block)
1915 && bitmap_bit_p (EXPR_DIES (block), id * 2))
1916 return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);
1918 /* A memory expression {e, VUSE} dies in the block if there is a
1919 statement that may clobber e. If, starting statement walk from the
1920 top of the basic block, a statement uses VUSE there can be no kill
1921 inbetween that use and the original statement that loaded {e, VUSE},
1922 so we can stop walking. */
1923 ref.base = NULL_TREE;
1924 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
1926 tree def_vuse, def_vdef;
1927 def = gsi_stmt (gsi);
1928 def_vuse = gimple_vuse (def);
1929 def_vdef = gimple_vdef (def);
1931 /* Not a memory statement. */
1935 /* Not a may-def. */
1938 /* A load with the same VUSE, we're done. */
1939 if (def_vuse == vuse)
1945 /* Init ref only if we really need it. */
1946 if (ref.base == NULL_TREE
1947 && !ao_ref_init_from_vn_reference (&ref, refx->set, refx->type,
1953 /* If the statement may clobber expr, it dies. */
1954 if (stmt_may_clobber_ref_p_1 (def, &ref))
1961 /* Remember the result. */
1962 if (!EXPR_DIES (block))
1963 EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
1964 bitmap_set_bit (EXPR_DIES (block), id * 2);
1966 bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);
1972 #define union_contains_value(SET1, SET2, VAL) \
1973 (bitmap_set_contains_value ((SET1), (VAL)) \
1974 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1976 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
1979 vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
1980 vn_reference_op_t vro)
1982 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
1984 struct pre_expr_d temp;
1987 PRE_EXPR_NAME (&temp) = vro->op0;
1988 temp.id = lookup_expression_id (&temp);
1991 if (!union_contains_value (set1, set2,
1992 get_expr_value_id (&temp)))
1995 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1997 struct pre_expr_d temp;
2000 PRE_EXPR_NAME (&temp) = vro->op1;
2001 temp.id = lookup_expression_id (&temp);
2004 if (!union_contains_value (set1, set2,
2005 get_expr_value_id (&temp)))
2009 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
2011 struct pre_expr_d temp;
2014 PRE_EXPR_NAME (&temp) = vro->op2;
2015 temp.id = lookup_expression_id (&temp);
2018 if (!union_contains_value (set1, set2,
2019 get_expr_value_id (&temp)))
2026 /* Determine if the expression EXPR is valid in SET1 U SET2.
2027 ONLY SET2 CAN BE NULL.
2028 This means that we have a leader for each part of the expression
2029 (if it consists of values), or the expression is an SSA_NAME.
2030 For loads/calls, we also see if the vuse is killed in this block. */
2033 valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
2039 return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
2043 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2044 for (i = 0; i < nary->length; i++)
2046 if (TREE_CODE (nary->op[i]) == SSA_NAME)
2048 struct pre_expr_d temp;
2051 PRE_EXPR_NAME (&temp) = nary->op[i];
2052 temp.id = lookup_expression_id (&temp);
2055 if (!union_contains_value (set1, set2,
2056 get_expr_value_id (&temp)))
2060 /* If the NARY may trap make sure the block does not contain
2061 a possible exit point.
2062 ??? This is overly conservative if we translate AVAIL_OUT
2063 as the available expression might be after the exit point. */
2064 if (BB_MAY_NOTRETURN (block)
2065 && vn_nary_may_trap (nary))
2072 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2073 vn_reference_op_t vro;
2076 for (i = 0; VEC_iterate (vn_reference_op_s, ref->operands, i, vro); i++)
2078 if (!vro_valid_in_sets (set1, set2, vro))
2083 gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
2084 if (!gimple_nop_p (def_stmt)
2085 && gimple_bb (def_stmt) != block
2086 && !dominated_by_p (CDI_DOMINATORS,
2087 block, gimple_bb (def_stmt)))
2090 return !value_dies_in_block_x (expr, block);
2097 /* Clean the set of expressions that are no longer valid in SET1 or
2098 SET2. This means expressions that are made up of values we have no
2099 leaders for in SET1 or SET2. This version is used for partial
2100 anticipation, which means it is not valid in either ANTIC_IN or
2104 dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
2106 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
2110 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2112 if (!valid_in_sets (set1, set2, expr, block))
2113 bitmap_remove_from_set (set1, expr);
2115 VEC_free (pre_expr, heap, exprs);
2118 /* Clean the set of expressions that are no longer valid in SET. This
2119 means expressions that are made up of values we have no leaders for
2123 clean (bitmap_set_t set, basic_block block)
2125 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
2129 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2131 if (!valid_in_sets (set, NULL, expr, block))
2132 bitmap_remove_from_set (set, expr);
2134 VEC_free (pre_expr, heap, exprs);
2137 static sbitmap has_abnormal_preds;
2139 /* List of blocks that may have changed during ANTIC computation and
2140 thus need to be iterated over. */
2142 static sbitmap changed_blocks;
2144 /* Decide whether to defer a block for a later iteration, or PHI
2145 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2146 should defer the block, and true if we processed it. */
2149 defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
2150 basic_block block, basic_block phiblock)
2152 if (!BB_VISITED (phiblock))
2154 SET_BIT (changed_blocks, block->index);
2155 BB_VISITED (block) = 0;
2156 BB_DEFERRED (block) = 1;
2160 phi_translate_set (dest, source, block, phiblock);
2164 /* Compute the ANTIC set for BLOCK.
2166 If succs(BLOCK) > 1 then
2167 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2168 else if succs(BLOCK) == 1 then
2169 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2171 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2175 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
2177 bool changed = false;
2178 bitmap_set_t S, old, ANTIC_OUT;
2184 old = ANTIC_OUT = S = NULL;
2185 BB_VISITED (block) = 1;
2187 /* If any edges from predecessors are abnormal, antic_in is empty,
2189 if (block_has_abnormal_pred_edge)
2190 goto maybe_dump_sets;
2192 old = ANTIC_IN (block);
2193 ANTIC_OUT = bitmap_set_new ();
2195 /* If the block has no successors, ANTIC_OUT is empty. */
2196 if (EDGE_COUNT (block->succs) == 0)
2198 /* If we have one successor, we could have some phi nodes to
2199 translate through. */
2200 else if (single_succ_p (block))
2202 basic_block succ_bb = single_succ (block);
2204 /* We trade iterations of the dataflow equations for having to
2205 phi translate the maximal set, which is incredibly slow
2206 (since the maximal set often has 300+ members, even when you
2207 have a small number of blocks).
2208 Basically, we defer the computation of ANTIC for this block
2209 until we have processed it's successor, which will inevitably
2210 have a *much* smaller set of values to phi translate once
2211 clean has been run on it.
2212 The cost of doing this is that we technically perform more
2213 iterations, however, they are lower cost iterations.
2215 Timings for PRE on tramp3d-v4:
2216 without maximal set fix: 11 seconds
2217 with maximal set fix/without deferring: 26 seconds
2218 with maximal set fix/with deferring: 11 seconds
2221 if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
2225 goto maybe_dump_sets;
2228 /* If we have multiple successors, we take the intersection of all of
2229 them. Note that in the case of loop exit phi nodes, we may have
2230 phis to translate through. */
2233 VEC(basic_block, heap) * worklist;
2235 basic_block bprime, first = NULL;
2237 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2238 FOR_EACH_EDGE (e, ei, block->succs)
2241 && BB_VISITED (e->dest))
2243 else if (BB_VISITED (e->dest))
2244 VEC_quick_push (basic_block, worklist, e->dest);
2247 /* Of multiple successors we have to have visited one already. */
2250 SET_BIT (changed_blocks, block->index);
2251 BB_VISITED (block) = 0;
2252 BB_DEFERRED (block) = 1;
2254 VEC_free (basic_block, heap, worklist);
2255 goto maybe_dump_sets;
2258 if (!gimple_seq_empty_p (phi_nodes (first)))
2259 phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
2261 bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
2263 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2265 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2267 bitmap_set_t tmp = bitmap_set_new ();
2268 phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
2269 bitmap_set_and (ANTIC_OUT, tmp);
2270 bitmap_set_free (tmp);
2273 bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
2275 VEC_free (basic_block, heap, worklist);
2278 /* Generate ANTIC_OUT - TMP_GEN. */
2279 S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
2281 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2282 ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
2285 /* Then union in the ANTIC_OUT - TMP_GEN values,
2286 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2287 FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
2288 bitmap_value_insert_into_set (ANTIC_IN (block),
2289 expression_for_id (bii));
2291 clean (ANTIC_IN (block), block);
2293 /* !old->expressions can happen when we deferred a block. */
2294 if (!old->expressions || !bitmap_set_equal (old, ANTIC_IN (block)))
2297 SET_BIT (changed_blocks, block->index);
2298 FOR_EACH_EDGE (e, ei, block->preds)
2299 SET_BIT (changed_blocks, e->src->index);
2302 RESET_BIT (changed_blocks, block->index);
2305 if (dump_file && (dump_flags & TDF_DETAILS))
2307 if (!BB_DEFERRED (block) || BB_VISITED (block))
2310 print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
2312 print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
2316 print_bitmap_set (dump_file, S, "S", block->index);
2321 "Block %d was deferred for a future iteration.\n",
2326 bitmap_set_free (old);
2328 bitmap_set_free (S);
2330 bitmap_set_free (ANTIC_OUT);
2334 /* Compute PARTIAL_ANTIC for BLOCK.
2336 If succs(BLOCK) > 1 then
2337 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2338 in ANTIC_OUT for all succ(BLOCK)
2339 else if succs(BLOCK) == 1 then
2340 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2342 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2347 compute_partial_antic_aux (basic_block block,
2348 bool block_has_abnormal_pred_edge)
2350 bool changed = false;
2351 bitmap_set_t old_PA_IN;
2352 bitmap_set_t PA_OUT;
2355 unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
2357 old_PA_IN = PA_OUT = NULL;
2359 /* If any edges from predecessors are abnormal, antic_in is empty,
2361 if (block_has_abnormal_pred_edge)
2362 goto maybe_dump_sets;
2364 /* If there are too many partially anticipatable values in the
2365 block, phi_translate_set can take an exponential time: stop
2366 before the translation starts. */
2368 && single_succ_p (block)
2369 && bitmap_count_bits (PA_IN (single_succ (block))->values) > max_pa)
2370 goto maybe_dump_sets;
2372 old_PA_IN = PA_IN (block);
2373 PA_OUT = bitmap_set_new ();
2375 /* If the block has no successors, ANTIC_OUT is empty. */
2376 if (EDGE_COUNT (block->succs) == 0)
2378 /* If we have one successor, we could have some phi nodes to
2379 translate through. Note that we can't phi translate across DFS
2380 back edges in partial antic, because it uses a union operation on
2381 the successors. For recurrences like IV's, we will end up
2382 generating a new value in the set on each go around (i + 3 (VH.1)
2383 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2384 else if (single_succ_p (block))
2386 basic_block succ = single_succ (block);
2387 if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
2388 phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
2390 /* If we have multiple successors, we take the union of all of
2394 VEC(basic_block, heap) * worklist;
2398 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2399 FOR_EACH_EDGE (e, ei, block->succs)
2401 if (e->flags & EDGE_DFS_BACK)
2403 VEC_quick_push (basic_block, worklist, e->dest);
2405 if (VEC_length (basic_block, worklist) > 0)
2407 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2412 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
2413 bitmap_value_insert_into_set (PA_OUT,
2414 expression_for_id (i));
2415 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2417 bitmap_set_t pa_in = bitmap_set_new ();
2418 phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
2419 FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
2420 bitmap_value_insert_into_set (PA_OUT,
2421 expression_for_id (i));
2422 bitmap_set_free (pa_in);
2425 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
2426 bitmap_value_insert_into_set (PA_OUT,
2427 expression_for_id (i));
2430 VEC_free (basic_block, heap, worklist);
2433 /* PA_IN starts with PA_OUT - TMP_GEN.
2434 Then we subtract things from ANTIC_IN. */
2435 PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
2437 /* For partial antic, we want to put back in the phi results, since
2438 we will properly avoid making them partially antic over backedges. */
2439 bitmap_ior_into (PA_IN (block)->values, PHI_GEN (block)->values);
2440 bitmap_ior_into (PA_IN (block)->expressions, PHI_GEN (block)->expressions);
2442 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2443 bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
2445 dependent_clean (PA_IN (block), ANTIC_IN (block), block);
2447 if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
2450 SET_BIT (changed_blocks, block->index);
2451 FOR_EACH_EDGE (e, ei, block->preds)
2452 SET_BIT (changed_blocks, e->src->index);
2455 RESET_BIT (changed_blocks, block->index);
2458 if (dump_file && (dump_flags & TDF_DETAILS))
2461 print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
2463 print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
2466 bitmap_set_free (old_PA_IN);
2468 bitmap_set_free (PA_OUT);
2472 /* Compute ANTIC and partial ANTIC sets. */
2475 compute_antic (void)
2477 bool changed = true;
2478 int num_iterations = 0;
2482 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2483 We pre-build the map of blocks with incoming abnormal edges here. */
2484 has_abnormal_preds = sbitmap_alloc (last_basic_block);
2485 sbitmap_zero (has_abnormal_preds);
2492 FOR_EACH_EDGE (e, ei, block->preds)
2494 e->flags &= ~EDGE_DFS_BACK;
2495 if (e->flags & EDGE_ABNORMAL)
2497 SET_BIT (has_abnormal_preds, block->index);
2502 BB_VISITED (block) = 0;
2503 BB_DEFERRED (block) = 0;
2505 /* While we are here, give empty ANTIC_IN sets to each block. */
2506 ANTIC_IN (block) = bitmap_set_new ();
2507 PA_IN (block) = bitmap_set_new ();
2510 /* At the exit block we anticipate nothing. */
2511 ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2512 BB_VISITED (EXIT_BLOCK_PTR) = 1;
2513 PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2515 changed_blocks = sbitmap_alloc (last_basic_block + 1);
2516 sbitmap_ones (changed_blocks);
2519 if (dump_file && (dump_flags & TDF_DETAILS))
2520 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2523 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1; i >= 0; i--)
2525 if (TEST_BIT (changed_blocks, postorder[i]))
2527 basic_block block = BASIC_BLOCK (postorder[i]);
2528 changed |= compute_antic_aux (block,
2529 TEST_BIT (has_abnormal_preds,
2533 #ifdef ENABLE_CHECKING
2534 /* Theoretically possible, but *highly* unlikely. */
2535 gcc_assert (num_iterations < 500);
2539 statistics_histogram_event (cfun, "compute_antic iterations",
2542 if (do_partial_partial)
2544 sbitmap_ones (changed_blocks);
2545 mark_dfs_back_edges ();
2550 if (dump_file && (dump_flags & TDF_DETAILS))
2551 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2554 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1 ; i >= 0; i--)
2556 if (TEST_BIT (changed_blocks, postorder[i]))
2558 basic_block block = BASIC_BLOCK (postorder[i]);
2560 |= compute_partial_antic_aux (block,
2561 TEST_BIT (has_abnormal_preds,
2565 #ifdef ENABLE_CHECKING
2566 /* Theoretically possible, but *highly* unlikely. */
2567 gcc_assert (num_iterations < 500);
2570 statistics_histogram_event (cfun, "compute_partial_antic iterations",
2573 sbitmap_free (has_abnormal_preds);
2574 sbitmap_free (changed_blocks);
2577 /* Return true if we can value number the call in STMT. This is true
2578 if we have a pure or constant call. */
2581 can_value_number_call (gimple stmt)
2583 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2588 /* Return true if OP is a tree which we can perform PRE on.
2589 This may not match the operations we can value number, but in
2590 a perfect world would. */
2593 can_PRE_operation (tree op)
2595 return UNARY_CLASS_P (op)
2596 || BINARY_CLASS_P (op)
2597 || COMPARISON_CLASS_P (op)
2598 || TREE_CODE (op) == INDIRECT_REF
2599 || TREE_CODE (op) == COMPONENT_REF
2600 || TREE_CODE (op) == VIEW_CONVERT_EXPR
2601 || TREE_CODE (op) == CALL_EXPR
2602 || TREE_CODE (op) == ARRAY_REF;
2606 /* Inserted expressions are placed onto this worklist, which is used
2607 for performing quick dead code elimination of insertions we made
2608 that didn't turn out to be necessary. */
2609 static bitmap inserted_exprs;
2611 /* Pool allocated fake store expressions are placed onto this
2612 worklist, which, after performing dead code elimination, is walked
2613 to see which expressions need to be put into GC'able memory */
2614 static VEC(gimple, heap) *need_creation;
2616 /* The actual worker for create_component_ref_by_pieces. */
2619 create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
2620 unsigned int *operand, gimple_seq *stmts,
2623 vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
2627 switch (currop->opcode)
2631 tree folded, sc = NULL_TREE;
2632 unsigned int nargs = 0;
2634 if (TREE_CODE (currop->op0) == FUNCTION_DECL)
2638 pre_expr op0 = get_or_alloc_expr_for (currop->op0);
2639 fn = find_or_generate_expression (block, op0, stmts, domstmt);
2645 pre_expr scexpr = get_or_alloc_expr_for (currop->op1);
2646 sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
2650 args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
2651 ref->operands) - 1);
2652 while (*operand < VEC_length (vn_reference_op_s, ref->operands))
2654 args[nargs] = create_component_ref_by_pieces_1 (block, ref,
2664 folded = build_call_array (currop->type,
2665 (TREE_CODE (fn) == FUNCTION_DECL
2666 ? build_fold_addr_expr (fn) : fn),
2670 CALL_EXPR_STATIC_CHAIN (folded) = sc;
2674 case TARGET_MEM_REF:
2676 vn_reference_op_t nextop = VEC_index (vn_reference_op_s, ref->operands,
2679 tree genop0 = NULL_TREE;
2680 tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
2686 op0expr = get_or_alloc_expr_for (currop->op0);
2687 genop0 = find_or_generate_expression (block, op0expr,
2692 if (DECL_P (baseop))
2693 return build6 (TARGET_MEM_REF, currop->type,
2695 genop0, currop->op1, currop->op2,
2696 unshare_expr (nextop->op1));
2698 return build6 (TARGET_MEM_REF, currop->type,
2700 genop0, currop->op1, currop->op2,
2701 unshare_expr (nextop->op1));
2707 gcc_assert (is_gimple_min_invariant (currop->op0));
2713 case VIEW_CONVERT_EXPR:
2716 tree genop0 = create_component_ref_by_pieces_1 (block, ref,
2721 folded = fold_build1 (currop->opcode, currop->type,
2726 case ALIGN_INDIRECT_REF:
2727 case MISALIGNED_INDIRECT_REF:
2731 tree genop1 = create_component_ref_by_pieces_1 (block, ref,
2736 genop1 = fold_convert (build_pointer_type (currop->type),
2739 if (currop->opcode == MISALIGNED_INDIRECT_REF)
2740 folded = fold_build2 (currop->opcode, currop->type,
2741 genop1, currop->op1);
2743 folded = fold_build1 (currop->opcode, currop->type,
2751 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2753 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2754 pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
2760 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2763 genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
2766 folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
2771 /* For array ref vn_reference_op's, operand 1 of the array ref
2772 is op0 of the reference op and operand 3 of the array ref is
2774 case ARRAY_RANGE_REF:
2778 tree genop1 = currop->op0;
2780 tree genop2 = currop->op1;
2782 tree genop3 = currop->op2;
2784 genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2788 op1expr = get_or_alloc_expr_for (genop1);
2789 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2794 /* Drop zero minimum index. */
2795 if (tree_int_cst_equal (genop2, integer_zero_node))
2799 op2expr = get_or_alloc_expr_for (genop2);
2800 genop2 = find_or_generate_expression (block, op2expr, stmts,
2808 tree elmt_type = TREE_TYPE (TREE_TYPE (genop0));
2809 /* We can't always put a size in units of the element alignment
2810 here as the element alignment may be not visible. See
2811 PR43783. Simply drop the element size for constant
2813 if (tree_int_cst_equal (genop3, TYPE_SIZE_UNIT (elmt_type)))
2817 genop3 = size_binop (EXACT_DIV_EXPR, genop3,
2818 size_int (TYPE_ALIGN_UNIT (elmt_type)));
2819 op3expr = get_or_alloc_expr_for (genop3);
2820 genop3 = find_or_generate_expression (block, op3expr, stmts,
2826 return build4 (currop->opcode, currop->type, genop0, genop1,
2833 tree genop2 = currop->op1;
2835 op0 = create_component_ref_by_pieces_1 (block, ref, operand,
2839 /* op1 should be a FIELD_DECL, which are represented by
2844 op2expr = get_or_alloc_expr_for (genop2);
2845 genop2 = find_or_generate_expression (block, op2expr, stmts,
2851 return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
2857 pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
2858 genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
2879 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2880 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2881 trying to rename aggregates into ssa form directly, which is a no no.
2883 Thus, this routine doesn't create temporaries, it just builds a
2884 single access expression for the array, calling
2885 find_or_generate_expression to build the innermost pieces.
2887 This function is a subroutine of create_expression_by_pieces, and
2888 should not be called on it's own unless you really know what you
2892 create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
2893 gimple_seq *stmts, gimple domstmt)
2895 unsigned int op = 0;
2896 return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
2899 /* Find a leader for an expression, or generate one using
2900 create_expression_by_pieces if it's ANTIC but
2902 BLOCK is the basic_block we are looking for leaders in.
2903 EXPR is the expression to find a leader or generate for.
2904 STMTS is the statement list to put the inserted expressions on.
2905 Returns the SSA_NAME of the LHS of the generated expression or the
2907 DOMSTMT if non-NULL is a statement that should be dominated by
2908 all uses in the generated expression. If DOMSTMT is non-NULL this
2909 routine can fail and return NULL_TREE. Otherwise it will assert
2913 find_or_generate_expression (basic_block block, pre_expr expr,
2914 gimple_seq *stmts, gimple domstmt)
2916 pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
2917 get_expr_value_id (expr), domstmt);
2921 if (leader->kind == NAME)
2922 genop = PRE_EXPR_NAME (leader);
2923 else if (leader->kind == CONSTANT)
2924 genop = PRE_EXPR_CONSTANT (leader);
2927 /* If it's still NULL, it must be a complex expression, so generate
2928 it recursively. Not so for FRE though. */
2932 bitmap_set_t exprset;
2933 unsigned int lookfor = get_expr_value_id (expr);
2934 bool handled = false;
2938 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
2939 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
2941 pre_expr temp = expression_for_id (i);
2942 if (temp->kind != NAME)
2945 genop = create_expression_by_pieces (block, temp, stmts,
2947 get_expr_type (expr));
2951 if (!handled && domstmt)
2954 gcc_assert (handled);
2959 #define NECESSARY GF_PLF_1
2961 /* Create an expression in pieces, so that we can handle very complex
2962 expressions that may be ANTIC, but not necessary GIMPLE.
2963 BLOCK is the basic block the expression will be inserted into,
2964 EXPR is the expression to insert (in value form)
2965 STMTS is a statement list to append the necessary insertions into.
2967 This function will die if we hit some value that shouldn't be
2968 ANTIC but is (IE there is no leader for it, or its components).
2969 This function may also generate expressions that are themselves
2970 partially or fully redundant. Those that are will be either made
2971 fully redundant during the next iteration of insert (for partially
2972 redundant ones), or eliminated by eliminate (for fully redundant
2975 If DOMSTMT is non-NULL then we make sure that all uses in the
2976 expressions dominate that statement. In this case the function
2977 can return NULL_TREE to signal failure. */
2980 create_expression_by_pieces (basic_block block, pre_expr expr,
2981 gimple_seq *stmts, gimple domstmt, tree type)
2985 gimple_seq forced_stmts = NULL;
2986 unsigned int value_id;
2987 gimple_stmt_iterator gsi;
2988 tree exprtype = type ? type : get_expr_type (expr);
2994 /* We may hit the NAME/CONSTANT case if we have to convert types
2995 that value numbering saw through. */
2997 folded = PRE_EXPR_NAME (expr);
3000 folded = PRE_EXPR_CONSTANT (expr);
3004 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
3005 folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
3010 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
3011 switch (nary->length)
3015 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
3016 pre_expr op2 = get_or_alloc_expr_for (nary->op[1]);
3017 tree genop1 = find_or_generate_expression (block, op1,
3019 tree genop2 = find_or_generate_expression (block, op2,
3021 if (!genop1 || !genop2)
3023 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
3024 may be a constant with the wrong type. */
3025 if (nary->opcode == POINTER_PLUS_EXPR)
3027 genop1 = fold_convert (nary->type, genop1);
3028 genop2 = fold_convert (sizetype, genop2);
3032 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3033 genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
3036 folded = fold_build2 (nary->opcode, nary->type,
3042 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
3043 tree genop1 = find_or_generate_expression (block, op1,
3047 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3049 folded = fold_build1 (nary->opcode, nary->type,
3062 if (!useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
3063 folded = fold_convert (exprtype, folded);
3065 /* Force the generated expression to be a sequence of GIMPLE
3067 We have to call unshare_expr because force_gimple_operand may
3068 modify the tree we pass to it. */
3069 folded = force_gimple_operand (unshare_expr (folded), &forced_stmts,
3072 /* If we have any intermediate expressions to the value sets, add them
3073 to the value sets and chain them in the instruction stream. */
3076 gsi = gsi_start (forced_stmts);
3077 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3079 gimple stmt = gsi_stmt (gsi);
3080 tree forcedname = gimple_get_lhs (stmt);
3083 if (TREE_CODE (forcedname) == SSA_NAME)
3085 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (forcedname));
3086 VN_INFO_GET (forcedname)->valnum = forcedname;
3087 VN_INFO (forcedname)->value_id = get_next_value_id ();
3088 nameexpr = get_or_alloc_expr_for_name (forcedname);
3089 add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
3091 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3092 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3094 mark_symbols_for_renaming (stmt);
3096 gimple_seq_add_seq (stmts, forced_stmts);
3099 /* Build and insert the assignment of the end result to the temporary
3100 that we will return. */
3101 if (!pretemp || exprtype != TREE_TYPE (pretemp))
3103 pretemp = create_tmp_reg (exprtype, "pretmp");
3104 get_var_ann (pretemp);
3108 add_referenced_var (temp);
3110 newstmt = gimple_build_assign (temp, folded);
3111 name = make_ssa_name (temp, newstmt);
3112 gimple_assign_set_lhs (newstmt, name);
3113 gimple_set_plf (newstmt, NECESSARY, false);
3115 gimple_seq_add_stmt (stmts, newstmt);
3116 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (name));
3118 /* All the symbols in NEWEXPR should be put into SSA form. */
3119 mark_symbols_for_renaming (newstmt);
3121 /* Add a value number to the temporary.
3122 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3123 we are creating the expression by pieces, and this particular piece of
3124 the expression may have been represented. There is no harm in replacing
3126 VN_INFO_GET (name)->valnum = name;
3127 value_id = get_expr_value_id (expr);
3128 VN_INFO (name)->value_id = value_id;
3129 nameexpr = get_or_alloc_expr_for_name (name);
3130 add_to_value (value_id, nameexpr);
3132 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3133 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3135 pre_stats.insertions++;
3136 if (dump_file && (dump_flags & TDF_DETAILS))
3138 fprintf (dump_file, "Inserted ");
3139 print_gimple_stmt (dump_file, newstmt, 0, 0);
3140 fprintf (dump_file, " in predecessor %d\n", block->index);
3147 /* Returns true if we want to inhibit the insertions of PHI nodes
3148 for the given EXPR for basic block BB (a member of a loop).
3149 We want to do this, when we fear that the induction variable we
3150 create might inhibit vectorization. */
3153 inhibit_phi_insertion (basic_block bb, pre_expr expr)
3155 vn_reference_t vr = PRE_EXPR_REFERENCE (expr);
3156 VEC (vn_reference_op_s, heap) *ops = vr->operands;
3157 vn_reference_op_t op;
3160 /* If we aren't going to vectorize we don't inhibit anything. */
3161 if (!flag_tree_vectorize)
3164 /* Otherwise we inhibit the insertion when the address of the
3165 memory reference is a simple induction variable. In other
3166 cases the vectorizer won't do anything anyway (either it's
3167 loop invariant or a complicated expression). */
3168 for (i = 0; VEC_iterate (vn_reference_op_s, ops, i, op); ++i)
3173 case ARRAY_RANGE_REF:
3174 if (TREE_CODE (op->op0) != SSA_NAME)
3179 basic_block defbb = gimple_bb (SSA_NAME_DEF_STMT (op->op0));
3181 /* Default defs are loop invariant. */
3184 /* Defined outside this loop, also loop invariant. */
3185 if (!flow_bb_inside_loop_p (bb->loop_father, defbb))
3187 /* If it's a simple induction variable inhibit insertion,
3188 the vectorizer might be interested in this one. */
3189 if (simple_iv (bb->loop_father, bb->loop_father,
3190 op->op0, &iv, true))
3192 /* No simple IV, vectorizer can't do anything, hence no
3193 reason to inhibit the transformation for this operand. */
3203 /* Insert the to-be-made-available values of expression EXPRNUM for each
3204 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3205 merge the result with a phi node, given the same value number as
3206 NODE. Return true if we have inserted new stuff. */
3209 insert_into_preds_of_block (basic_block block, unsigned int exprnum,
3212 pre_expr expr = expression_for_id (exprnum);
3214 unsigned int val = get_expr_value_id (expr);
3216 bool insertions = false;
3221 tree type = get_expr_type (expr);
3225 if (dump_file && (dump_flags & TDF_DETAILS))
3227 fprintf (dump_file, "Found partial redundancy for expression ");
3228 print_pre_expr (dump_file, expr);
3229 fprintf (dump_file, " (%04d)\n", val);
3232 /* Make sure we aren't creating an induction variable. */
3233 if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2)
3235 bool firstinsideloop = false;
3236 bool secondinsideloop = false;
3237 firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
3238 EDGE_PRED (block, 0)->src);
3239 secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
3240 EDGE_PRED (block, 1)->src);
3241 /* Induction variables only have one edge inside the loop. */
3242 if ((firstinsideloop ^ secondinsideloop)
3243 && (expr->kind != REFERENCE
3244 || inhibit_phi_insertion (block, expr)))
3246 if (dump_file && (dump_flags & TDF_DETAILS))
3247 fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3252 /* Make the necessary insertions. */
3253 FOR_EACH_EDGE (pred, ei, block->preds)
3255 gimple_seq stmts = NULL;
3258 eprime = avail[bprime->index];
3260 if (eprime->kind != NAME && eprime->kind != CONSTANT)
3262 builtexpr = create_expression_by_pieces (bprime,
3266 gcc_assert (!(pred->flags & EDGE_ABNORMAL));
3267 gsi_insert_seq_on_edge (pred, stmts);
3268 avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
3271 else if (eprime->kind == CONSTANT)
3273 /* Constants may not have the right type, fold_convert
3274 should give us back a constant with the right type.
3276 tree constant = PRE_EXPR_CONSTANT (eprime);
3277 if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
3279 tree builtexpr = fold_convert (type, constant);
3280 if (!is_gimple_min_invariant (builtexpr))
3282 tree forcedexpr = force_gimple_operand (builtexpr,
3285 if (!is_gimple_min_invariant (forcedexpr))
3287 if (forcedexpr != builtexpr)
3289 VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
3290 VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
3294 gimple_stmt_iterator gsi;
3295 gsi = gsi_start (stmts);
3296 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3298 gimple stmt = gsi_stmt (gsi);
3299 tree lhs = gimple_get_lhs (stmt);
3300 if (TREE_CODE (lhs) == SSA_NAME)
3301 bitmap_set_bit (inserted_exprs,
3302 SSA_NAME_VERSION (lhs));
3303 gimple_set_plf (stmt, NECESSARY, false);
3305 gsi_insert_seq_on_edge (pred, stmts);
3307 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3312 else if (eprime->kind == NAME)
3314 /* We may have to do a conversion because our value
3315 numbering can look through types in certain cases, but
3316 our IL requires all operands of a phi node have the same
3318 tree name = PRE_EXPR_NAME (eprime);
3319 if (!useless_type_conversion_p (type, TREE_TYPE (name)))
3323 builtexpr = fold_convert (type, name);
3324 forcedexpr = force_gimple_operand (builtexpr,
3328 if (forcedexpr != name)
3330 VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
3331 VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
3336 gimple_stmt_iterator gsi;
3337 gsi = gsi_start (stmts);
3338 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3340 gimple stmt = gsi_stmt (gsi);
3341 tree lhs = gimple_get_lhs (stmt);
3342 if (TREE_CODE (lhs) == SSA_NAME)
3343 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
3344 gimple_set_plf (stmt, NECESSARY, false);
3346 gsi_insert_seq_on_edge (pred, stmts);
3348 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3352 /* If we didn't want a phi node, and we made insertions, we still have
3353 inserted new stuff, and thus return true. If we didn't want a phi node,
3354 and didn't make insertions, we haven't added anything new, so return
3356 if (nophi && insertions)
3358 else if (nophi && !insertions)
3361 /* Now build a phi for the new variable. */
3362 if (!prephitemp || TREE_TYPE (prephitemp) != type)
3364 prephitemp = create_tmp_var (type, "prephitmp");
3365 get_var_ann (prephitemp);
3369 add_referenced_var (temp);
3371 if (TREE_CODE (type) == COMPLEX_TYPE
3372 || TREE_CODE (type) == VECTOR_TYPE)
3373 DECL_GIMPLE_REG_P (temp) = 1;
3374 phi = create_phi_node (temp, block);
3376 gimple_set_plf (phi, NECESSARY, false);
3377 VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
3378 VN_INFO (gimple_phi_result (phi))->value_id = val;
3379 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (gimple_phi_result (phi)));
3380 FOR_EACH_EDGE (pred, ei, block->preds)
3382 pre_expr ae = avail[pred->src->index];
3383 gcc_assert (get_expr_type (ae) == type
3384 || useless_type_conversion_p (type, get_expr_type (ae)));
3385 if (ae->kind == CONSTANT)
3386 add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred, UNKNOWN_LOCATION);
3388 add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred,
3392 newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
3393 add_to_value (val, newphi);
3395 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3396 this insertion, since we test for the existence of this value in PHI_GEN
3397 before proceeding with the partial redundancy checks in insert_aux.
3399 The value may exist in AVAIL_OUT, in particular, it could be represented
3400 by the expression we are trying to eliminate, in which case we want the
3401 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3404 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3405 this block, because if it did, it would have existed in our dominator's
3406 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3409 bitmap_insert_into_set (PHI_GEN (block), newphi);
3410 bitmap_value_replace_in_set (AVAIL_OUT (block),
3412 bitmap_insert_into_set (NEW_SETS (block),
3415 if (dump_file && (dump_flags & TDF_DETAILS))
3417 fprintf (dump_file, "Created phi ");
3418 print_gimple_stmt (dump_file, phi, 0, 0);
3419 fprintf (dump_file, " in block %d\n", block->index);
3427 /* Perform insertion of partially redundant values.
3428 For BLOCK, do the following:
3429 1. Propagate the NEW_SETS of the dominator into the current block.
3430 If the block has multiple predecessors,
3431 2a. Iterate over the ANTIC expressions for the block to see if
3432 any of them are partially redundant.
3433 2b. If so, insert them into the necessary predecessors to make
3434 the expression fully redundant.
3435 2c. Insert a new PHI merging the values of the predecessors.
3436 2d. Insert the new PHI, and the new expressions, into the
3438 3. Recursively call ourselves on the dominator children of BLOCK.
3440 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3441 do_regular_insertion and do_partial_insertion.
3446 do_regular_insertion (basic_block block, basic_block dom)
3448 bool new_stuff = false;
3449 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
3453 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3455 if (expr->kind != NAME)
3459 bool by_some = false;
3460 bool cant_insert = false;
3461 bool all_same = true;
3462 pre_expr first_s = NULL;
3465 pre_expr eprime = NULL;
3467 pre_expr edoubleprime = NULL;
3468 bool do_insertion = false;
3470 val = get_expr_value_id (expr);
3471 if (bitmap_set_contains_value (PHI_GEN (block), val))
3473 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3475 if (dump_file && (dump_flags & TDF_DETAILS))
3476 fprintf (dump_file, "Found fully redundant value\n");
3480 avail = XCNEWVEC (pre_expr, last_basic_block);
3481 FOR_EACH_EDGE (pred, ei, block->preds)
3483 unsigned int vprime;
3485 /* We should never run insertion for the exit block
3486 and so not come across fake pred edges. */
3487 gcc_assert (!(pred->flags & EDGE_FAKE));
3489 eprime = phi_translate (expr, ANTIC_IN (block), NULL,
3492 /* eprime will generally only be NULL if the
3493 value of the expression, translated
3494 through the PHI for this predecessor, is
3495 undefined. If that is the case, we can't
3496 make the expression fully redundant,
3497 because its value is undefined along a
3498 predecessor path. We can thus break out
3499 early because it doesn't matter what the
3500 rest of the results are. */
3507 eprime = fully_constant_expression (eprime);
3508 vprime = get_expr_value_id (eprime);
3509 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3511 if (edoubleprime == NULL)
3513 avail[bprime->index] = eprime;
3518 avail[bprime->index] = edoubleprime;
3520 /* We want to perform insertions to remove a redundancy on
3521 a path in the CFG we want to optimize for speed. */
3522 if (optimize_edge_for_speed_p (pred))
3523 do_insertion = true;
3524 if (first_s == NULL)
3525 first_s = edoubleprime;
3526 else if (!pre_expr_eq (first_s, edoubleprime))
3530 /* If we can insert it, it's not the same value
3531 already existing along every predecessor, and
3532 it's defined by some predecessor, it is
3533 partially redundant. */
3534 if (!cant_insert && !all_same && by_some && do_insertion
3535 && dbg_cnt (treepre_insert))
3537 if (insert_into_preds_of_block (block, get_expression_id (expr),
3541 /* If all edges produce the same value and that value is
3542 an invariant, then the PHI has the same value on all
3543 edges. Note this. */
3544 else if (!cant_insert && all_same && eprime
3545 && (edoubleprime->kind == CONSTANT
3546 || edoubleprime->kind == NAME)
3547 && !value_id_constant_p (val))
3551 bitmap_set_t exprset = VEC_index (bitmap_set_t,
3552 value_expressions, val);
3554 unsigned int new_val = get_expr_value_id (edoubleprime);
3555 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bi)
3557 pre_expr expr = expression_for_id (j);
3559 if (expr->kind == NAME)
3561 vn_ssa_aux_t info = VN_INFO (PRE_EXPR_NAME (expr));
3562 /* Just reset the value id and valnum so it is
3563 the same as the constant we have discovered. */
3564 if (edoubleprime->kind == CONSTANT)
3566 info->valnum = PRE_EXPR_CONSTANT (edoubleprime);
3567 pre_stats.constified++;
3570 info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
3571 info->value_id = new_val;
3579 VEC_free (pre_expr, heap, exprs);
3584 /* Perform insertion for partially anticipatable expressions. There
3585 is only one case we will perform insertion for these. This case is
3586 if the expression is partially anticipatable, and fully available.
3587 In this case, we know that putting it earlier will enable us to
3588 remove the later computation. */
3592 do_partial_partial_insertion (basic_block block, basic_block dom)
3594 bool new_stuff = false;
3595 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (PA_IN (block));
3599 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3601 if (expr->kind != NAME)
3606 bool cant_insert = false;
3609 pre_expr eprime = NULL;
3612 val = get_expr_value_id (expr);
3613 if (bitmap_set_contains_value (PHI_GEN (block), val))
3615 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3618 avail = XCNEWVEC (pre_expr, last_basic_block);
3619 FOR_EACH_EDGE (pred, ei, block->preds)
3621 unsigned int vprime;
3622 pre_expr edoubleprime;
3624 /* We should never run insertion for the exit block
3625 and so not come across fake pred edges. */
3626 gcc_assert (!(pred->flags & EDGE_FAKE));
3628 eprime = phi_translate (expr, ANTIC_IN (block),
3632 /* eprime will generally only be NULL if the
3633 value of the expression, translated
3634 through the PHI for this predecessor, is
3635 undefined. If that is the case, we can't
3636 make the expression fully redundant,
3637 because its value is undefined along a
3638 predecessor path. We can thus break out
3639 early because it doesn't matter what the
3640 rest of the results are. */
3647 eprime = fully_constant_expression (eprime);
3648 vprime = get_expr_value_id (eprime);
3649 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3651 if (edoubleprime == NULL)
3657 avail[bprime->index] = edoubleprime;
3661 /* If we can insert it, it's not the same value
3662 already existing along every predecessor, and
3663 it's defined by some predecessor, it is
3664 partially redundant. */
3665 if (!cant_insert && by_all && dbg_cnt (treepre_insert))
3667 pre_stats.pa_insert++;
3668 if (insert_into_preds_of_block (block, get_expression_id (expr),
3676 VEC_free (pre_expr, heap, exprs);
3681 insert_aux (basic_block block)
3684 bool new_stuff = false;
3689 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3694 bitmap_set_t newset = NEW_SETS (dom);
3697 /* Note that we need to value_replace both NEW_SETS, and
3698 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3699 represented by some non-simple expression here that we want
3700 to replace it with. */
3701 FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
3703 pre_expr expr = expression_for_id (i);
3704 bitmap_value_replace_in_set (NEW_SETS (block), expr);
3705 bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
3708 if (!single_pred_p (block))
3710 new_stuff |= do_regular_insertion (block, dom);
3711 if (do_partial_partial)
3712 new_stuff |= do_partial_partial_insertion (block, dom);
3716 for (son = first_dom_son (CDI_DOMINATORS, block);
3718 son = next_dom_son (CDI_DOMINATORS, son))
3720 new_stuff |= insert_aux (son);
3726 /* Perform insertion of partially redundant values. */
3731 bool new_stuff = true;
3733 int num_iterations = 0;
3736 NEW_SETS (bb) = bitmap_set_new ();
3741 new_stuff = insert_aux (ENTRY_BLOCK_PTR);
3743 statistics_histogram_event (cfun, "insert iterations", num_iterations);
3747 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3750 add_to_exp_gen (basic_block block, tree op)
3755 if (TREE_CODE (op) == SSA_NAME && ssa_undefined_value_p (op))
3757 result = get_or_alloc_expr_for_name (op);
3758 bitmap_value_insert_into_set (EXP_GEN (block), result);
3762 /* Create value ids for PHI in BLOCK. */
3765 make_values_for_phi (gimple phi, basic_block block)
3767 tree result = gimple_phi_result (phi);
3769 /* We have no need for virtual phis, as they don't represent
3770 actual computations. */
3771 if (is_gimple_reg (result))
3773 pre_expr e = get_or_alloc_expr_for_name (result);
3774 add_to_value (get_expr_value_id (e), e);
3775 bitmap_insert_into_set (PHI_GEN (block), e);
3776 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3780 for (i = 0; i < gimple_phi_num_args (phi); ++i)
3782 tree arg = gimple_phi_arg_def (phi, i);
3783 if (TREE_CODE (arg) == SSA_NAME)
3785 e = get_or_alloc_expr_for_name (arg);
3786 add_to_value (get_expr_value_id (e), e);
3793 /* Compute the AVAIL set for all basic blocks.
3795 This function performs value numbering of the statements in each basic
3796 block. The AVAIL sets are built from information we glean while doing
3797 this value numbering, since the AVAIL sets contain only one entry per
3800 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3801 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3804 compute_avail (void)
3807 basic_block block, son;
3808 basic_block *worklist;
3812 /* We pretend that default definitions are defined in the entry block.
3813 This includes function arguments and the static chain decl. */
3814 for (i = 1; i < num_ssa_names; ++i)
3816 tree name = ssa_name (i);
3819 || !SSA_NAME_IS_DEFAULT_DEF (name)
3820 || has_zero_uses (name)
3821 || !is_gimple_reg (name))
3824 e = get_or_alloc_expr_for_name (name);
3825 add_to_value (get_expr_value_id (e), e);
3827 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
3828 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
3831 /* Allocate the worklist. */
3832 worklist = XNEWVEC (basic_block, n_basic_blocks);
3834 /* Seed the algorithm by putting the dominator children of the entry
3835 block on the worklist. */
3836 for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
3838 son = next_dom_son (CDI_DOMINATORS, son))
3839 worklist[sp++] = son;
3841 /* Loop until the worklist is empty. */
3844 gimple_stmt_iterator gsi;
3847 unsigned int stmt_uid = 1;
3849 /* Pick a block from the worklist. */
3850 block = worklist[--sp];
3852 /* Initially, the set of available values in BLOCK is that of
3853 its immediate dominator. */
3854 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3856 bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
3858 /* Generate values for PHI nodes. */
3859 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
3860 make_values_for_phi (gsi_stmt (gsi), block);
3862 BB_MAY_NOTRETURN (block) = 0;
3864 /* Now compute value numbers and populate value sets with all
3865 the expressions computed in BLOCK. */
3866 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
3871 stmt = gsi_stmt (gsi);
3872 gimple_set_uid (stmt, stmt_uid++);
3874 /* Cache whether the basic-block has any non-visible side-effect
3876 If this isn't a call or it is the last stmt in the
3877 basic-block then the CFG represents things correctly. */
3878 if (is_gimple_call (stmt)
3879 && !stmt_ends_bb_p (stmt))
3881 /* Non-looping const functions always return normally.
3882 Otherwise the call might not return or have side-effects
3883 that forbids hoisting possibly trapping expressions
3885 int flags = gimple_call_flags (stmt);
3886 if (!(flags & ECF_CONST)
3887 || (flags & ECF_LOOPING_CONST_OR_PURE))
3888 BB_MAY_NOTRETURN (block) = 1;
3891 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
3893 pre_expr e = get_or_alloc_expr_for_name (op);
3895 add_to_value (get_expr_value_id (e), e);
3897 bitmap_insert_into_set (TMP_GEN (block), e);
3898 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3901 if (gimple_has_volatile_ops (stmt)
3902 || stmt_could_throw_p (stmt))
3905 switch (gimple_code (stmt))
3908 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3909 add_to_exp_gen (block, op);
3916 vn_reference_op_t vro;
3917 pre_expr result = NULL;
3918 VEC(vn_reference_op_s, heap) *ops = NULL;
3920 if (!can_value_number_call (stmt))
3923 copy_reference_ops_from_call (stmt, &ops);
3924 vn_reference_lookup_pieces (gimple_vuse (stmt), 0,
3925 gimple_expr_type (stmt),
3927 VEC_free (vn_reference_op_s, heap, ops);
3931 for (i = 0; VEC_iterate (vn_reference_op_s,
3935 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3936 add_to_exp_gen (block, vro->op0);
3937 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3938 add_to_exp_gen (block, vro->op1);
3939 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3940 add_to_exp_gen (block, vro->op2);
3942 result = (pre_expr) pool_alloc (pre_expr_pool);
3943 result->kind = REFERENCE;
3945 PRE_EXPR_REFERENCE (result) = ref;
3947 get_or_alloc_expression_id (result);
3948 add_to_value (get_expr_value_id (result), result);
3950 bitmap_value_insert_into_set (EXP_GEN (block), result);
3956 pre_expr result = NULL;
3957 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
3961 case tcc_comparison:
3966 vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
3967 gimple_assign_rhs_code (stmt),
3968 gimple_expr_type (stmt),
3969 gimple_assign_rhs1 (stmt),
3970 gimple_assign_rhs2 (stmt),
3971 NULL_TREE, NULL_TREE, &nary);
3976 for (i = 0; i < nary->length; i++)
3977 if (TREE_CODE (nary->op[i]) == SSA_NAME)
3978 add_to_exp_gen (block, nary->op[i]);
3980 result = (pre_expr) pool_alloc (pre_expr_pool);
3981 result->kind = NARY;
3983 PRE_EXPR_NARY (result) = nary;
3987 case tcc_declaration:
3992 vn_reference_op_t vro;
3994 vn_reference_lookup (gimple_assign_rhs1 (stmt),
4000 for (i = 0; VEC_iterate (vn_reference_op_s,
4004 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
4005 add_to_exp_gen (block, vro->op0);
4006 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
4007 add_to_exp_gen (block, vro->op1);
4008 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
4009 add_to_exp_gen (block, vro->op2);
4011 result = (pre_expr) pool_alloc (pre_expr_pool);
4012 result->kind = REFERENCE;
4014 PRE_EXPR_REFERENCE (result) = ref;
4019 /* For any other statement that we don't
4020 recognize, simply add all referenced
4021 SSA_NAMEs to EXP_GEN. */
4022 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
4023 add_to_exp_gen (block, op);
4027 get_or_alloc_expression_id (result);
4028 add_to_value (get_expr_value_id (result), result);
4030 bitmap_value_insert_into_set (EXP_GEN (block), result);
4039 /* Put the dominator children of BLOCK on the worklist of blocks
4040 to compute available sets for. */
4041 for (son = first_dom_son (CDI_DOMINATORS, block);
4043 son = next_dom_son (CDI_DOMINATORS, son))
4044 worklist[sp++] = son;
4050 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
4051 than the available expressions for it. The insertion point is
4052 right before the first use in STMT. Returns the SSA_NAME that should
4053 be used for replacement. */
4056 do_SCCVN_insertion (gimple stmt, tree ssa_vn)
4058 basic_block bb = gimple_bb (stmt);
4059 gimple_stmt_iterator gsi;
4060 gimple_seq stmts = NULL;
4064 /* First create a value expression from the expression we want
4065 to insert and associate it with the value handle for SSA_VN. */
4066 e = get_or_alloc_expr_for (vn_get_expr_for (ssa_vn));
4070 /* Then use create_expression_by_pieces to generate a valid
4071 expression to insert at this point of the IL stream. */
4072 expr = create_expression_by_pieces (bb, e, &stmts, stmt, NULL);
4073 if (expr == NULL_TREE)
4075 gsi = gsi_for_stmt (stmt);
4076 gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
4081 /* Eliminate fully redundant computations. */
4086 VEC (gimple, heap) *to_remove = NULL;
4088 unsigned int todo = 0;
4089 gimple_stmt_iterator gsi;
4095 for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
4097 stmt = gsi_stmt (gsi);
4099 /* Lookup the RHS of the expression, see if we have an
4100 available computation for it. If so, replace the RHS with
4101 the available computation. */
4102 if (gimple_has_lhs (stmt)
4103 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
4104 && !gimple_assign_ssa_name_copy_p (stmt)
4105 && (!gimple_assign_single_p (stmt)
4106 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
4107 && !gimple_has_volatile_ops (stmt)
4108 && !has_zero_uses (gimple_get_lhs (stmt)))
4110 tree lhs = gimple_get_lhs (stmt);
4111 tree rhs = NULL_TREE;
4113 pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
4114 pre_expr sprimeexpr;
4116 if (gimple_assign_single_p (stmt))
4117 rhs = gimple_assign_rhs1 (stmt);
4119 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4120 get_expr_value_id (lhsexpr),
4125 if (sprimeexpr->kind == CONSTANT)
4126 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4127 else if (sprimeexpr->kind == NAME)
4128 sprime = PRE_EXPR_NAME (sprimeexpr);
4133 /* If there is no existing leader but SCCVN knows this
4134 value is constant, use that constant. */
4135 if (!sprime && is_gimple_min_invariant (VN_INFO (lhs)->valnum))
4137 sprime = VN_INFO (lhs)->valnum;
4138 if (!useless_type_conversion_p (TREE_TYPE (lhs),
4139 TREE_TYPE (sprime)))
4140 sprime = fold_convert (TREE_TYPE (lhs), sprime);
4142 if (dump_file && (dump_flags & TDF_DETAILS))
4144 fprintf (dump_file, "Replaced ");
4145 print_gimple_expr (dump_file, stmt, 0, 0);
4146 fprintf (dump_file, " with ");
4147 print_generic_expr (dump_file, sprime, 0);
4148 fprintf (dump_file, " in ");
4149 print_gimple_stmt (dump_file, stmt, 0, 0);
4151 pre_stats.eliminations++;
4152 propagate_tree_value_into_stmt (&gsi, sprime);
4153 stmt = gsi_stmt (gsi);
4158 /* If there is no existing usable leader but SCCVN thinks
4159 it has an expression it wants to use as replacement,
4161 if (!sprime || sprime == lhs)
4163 tree val = VN_INFO (lhs)->valnum;
4165 && TREE_CODE (val) == SSA_NAME
4166 && VN_INFO (val)->needs_insertion
4167 && can_PRE_operation (vn_get_expr_for (val)))
4168 sprime = do_SCCVN_insertion (stmt, val);
4172 && (rhs == NULL_TREE
4173 || TREE_CODE (rhs) != SSA_NAME
4174 || may_propagate_copy (rhs, sprime)))
4176 gcc_assert (sprime != rhs);
4178 if (dump_file && (dump_flags & TDF_DETAILS))
4180 fprintf (dump_file, "Replaced ");
4181 print_gimple_expr (dump_file, stmt, 0, 0);
4182 fprintf (dump_file, " with ");
4183 print_generic_expr (dump_file, sprime, 0);
4184 fprintf (dump_file, " in ");
4185 print_gimple_stmt (dump_file, stmt, 0, 0);
4188 if (TREE_CODE (sprime) == SSA_NAME)
4189 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4191 /* We need to make sure the new and old types actually match,
4192 which may require adding a simple cast, which fold_convert
4194 if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
4195 && !useless_type_conversion_p (gimple_expr_type (stmt),
4196 TREE_TYPE (sprime)))
4197 sprime = fold_convert (gimple_expr_type (stmt), sprime);
4199 pre_stats.eliminations++;
4200 propagate_tree_value_into_stmt (&gsi, sprime);
4201 stmt = gsi_stmt (gsi);
4204 /* If we removed EH side effects from the statement, clean
4205 its EH information. */
4206 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4208 bitmap_set_bit (need_eh_cleanup,
4209 gimple_bb (stmt)->index);
4210 if (dump_file && (dump_flags & TDF_DETAILS))
4211 fprintf (dump_file, " Removed EH side effects.\n");
4215 /* If the statement is a scalar store, see if the expression
4216 has the same value number as its rhs. If so, the store is
4218 else if (gimple_assign_single_p (stmt)
4219 && !is_gimple_reg (gimple_assign_lhs (stmt))
4220 && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
4221 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
4223 tree rhs = gimple_assign_rhs1 (stmt);
4225 val = vn_reference_lookup (gimple_assign_lhs (stmt),
4226 gimple_vuse (stmt), true, NULL);
4227 if (TREE_CODE (rhs) == SSA_NAME)
4228 rhs = VN_INFO (rhs)->valnum;
4230 && operand_equal_p (val, rhs, 0))
4232 if (dump_file && (dump_flags & TDF_DETAILS))
4234 fprintf (dump_file, "Deleted redundant store ");
4235 print_gimple_stmt (dump_file, stmt, 0, 0);
4238 /* Queue stmt for removal. */
4239 VEC_safe_push (gimple, heap, to_remove, stmt);
4242 /* Visit COND_EXPRs and fold the comparison with the
4243 available value-numbers. */
4244 else if (gimple_code (stmt) == GIMPLE_COND)
4246 tree op0 = gimple_cond_lhs (stmt);
4247 tree op1 = gimple_cond_rhs (stmt);
4250 if (TREE_CODE (op0) == SSA_NAME)
4251 op0 = VN_INFO (op0)->valnum;
4252 if (TREE_CODE (op1) == SSA_NAME)
4253 op1 = VN_INFO (op1)->valnum;
4254 result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
4256 if (result && TREE_CODE (result) == INTEGER_CST)
4258 if (integer_zerop (result))
4259 gimple_cond_make_false (stmt);
4261 gimple_cond_make_true (stmt);
4263 todo = TODO_cleanup_cfg;
4266 /* Visit indirect calls and turn them into direct calls if
4268 if (gimple_code (stmt) == GIMPLE_CALL
4269 && TREE_CODE (gimple_call_fn (stmt)) == SSA_NAME)
4271 tree fn = VN_INFO (gimple_call_fn (stmt))->valnum;
4272 if (TREE_CODE (fn) == ADDR_EXPR
4273 && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL)
4275 if (dump_file && (dump_flags & TDF_DETAILS))
4277 fprintf (dump_file, "Replacing call target with ");
4278 print_generic_expr (dump_file, fn, 0);
4279 fprintf (dump_file, " in ");
4280 print_gimple_stmt (dump_file, stmt, 0, 0);
4283 gimple_call_set_fn (stmt, fn);
4285 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4287 bitmap_set_bit (need_eh_cleanup,
4288 gimple_bb (stmt)->index);
4289 if (dump_file && (dump_flags & TDF_DETAILS))
4290 fprintf (dump_file, " Removed EH side effects.\n");
4293 /* Changing an indirect call to a direct call may
4294 have exposed different semantics. This may
4295 require an SSA update. */
4296 todo |= TODO_update_ssa_only_virtuals;
4301 for (gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
4303 gimple stmt, phi = gsi_stmt (gsi);
4304 tree sprime = NULL_TREE, res = PHI_RESULT (phi);
4305 pre_expr sprimeexpr, resexpr;
4306 gimple_stmt_iterator gsi2;
4308 /* We want to perform redundant PHI elimination. Do so by
4309 replacing the PHI with a single copy if possible.
4310 Do not touch inserted, single-argument or virtual PHIs. */
4311 if (gimple_phi_num_args (phi) == 1
4312 || !is_gimple_reg (res))
4318 resexpr = get_or_alloc_expr_for_name (res);
4319 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4320 get_expr_value_id (resexpr), NULL);
4323 if (sprimeexpr->kind == CONSTANT)
4324 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4325 else if (sprimeexpr->kind == NAME)
4326 sprime = PRE_EXPR_NAME (sprimeexpr);
4337 if (dump_file && (dump_flags & TDF_DETAILS))
4339 fprintf (dump_file, "Replaced redundant PHI node defining ");
4340 print_generic_expr (dump_file, res, 0);
4341 fprintf (dump_file, " with ");
4342 print_generic_expr (dump_file, sprime, 0);
4343 fprintf (dump_file, "\n");
4346 remove_phi_node (&gsi, false);
4348 if (!bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res))
4349 && TREE_CODE (sprime) == SSA_NAME)
4350 gimple_set_plf (SSA_NAME_DEF_STMT (sprime), NECESSARY, true);
4352 if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
4353 sprime = fold_convert (TREE_TYPE (res), sprime);
4354 stmt = gimple_build_assign (res, sprime);
4355 SSA_NAME_DEF_STMT (res) = stmt;
4356 gimple_set_plf (stmt, NECESSARY, gimple_plf (phi, NECESSARY));
4358 gsi2 = gsi_after_labels (b);
4359 gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
4360 /* Queue the copy for eventual removal. */
4361 VEC_safe_push (gimple, heap, to_remove, stmt);
4362 /* If we inserted this PHI node ourself, it's not an elimination. */
4363 if (bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res)))
4366 pre_stats.eliminations++;
4370 /* We cannot remove stmts during BB walk, especially not release SSA
4371 names there as this confuses the VN machinery. The stmts ending
4372 up in to_remove are either stores or simple copies. */
4373 for (i = 0; VEC_iterate (gimple, to_remove, i, stmt); ++i)
4375 tree lhs = gimple_assign_lhs (stmt);
4376 tree rhs = gimple_assign_rhs1 (stmt);
4377 use_operand_p use_p;
4380 /* If there is a single use only, propagate the equivalency
4381 instead of keeping the copy. */
4382 if (TREE_CODE (lhs) == SSA_NAME
4383 && TREE_CODE (rhs) == SSA_NAME
4384 && single_imm_use (lhs, &use_p, &use_stmt)
4385 && may_propagate_copy (USE_FROM_PTR (use_p), rhs))
4387 SET_USE (use_p, rhs);
4388 update_stmt (use_stmt);
4389 if (bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (lhs))
4390 && TREE_CODE (rhs) == SSA_NAME)
4391 gimple_set_plf (SSA_NAME_DEF_STMT (rhs), NECESSARY, true);
4394 /* If this is a store or a now unused copy, remove it. */
4395 if (TREE_CODE (lhs) != SSA_NAME
4396 || has_zero_uses (lhs))
4398 gsi = gsi_for_stmt (stmt);
4399 unlink_stmt_vdef (stmt);
4400 gsi_remove (&gsi, true);
4401 if (TREE_CODE (lhs) == SSA_NAME)
4402 bitmap_clear_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
4403 release_defs (stmt);
4406 VEC_free (gimple, heap, to_remove);
4411 /* Borrow a bit of tree-ssa-dce.c for the moment.
4412 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4413 this may be a bit faster, and we may want critical edges kept split. */
4415 /* If OP's defining statement has not already been determined to be necessary,
4416 mark that statement necessary. Return the stmt, if it is newly
4419 static inline gimple
4420 mark_operand_necessary (tree op)
4426 if (TREE_CODE (op) != SSA_NAME)
4429 stmt = SSA_NAME_DEF_STMT (op);
4432 if (gimple_plf (stmt, NECESSARY)
4433 || gimple_nop_p (stmt))
4436 gimple_set_plf (stmt, NECESSARY, true);
4440 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4441 to insert PHI nodes sometimes, and because value numbering of casts isn't
4442 perfect, we sometimes end up inserting dead code. This simple DCE-like
4443 pass removes any insertions we made that weren't actually used. */
4446 remove_dead_inserted_code (void)
4453 worklist = BITMAP_ALLOC (NULL);
4454 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
4456 t = SSA_NAME_DEF_STMT (ssa_name (i));
4457 if (gimple_plf (t, NECESSARY))
4458 bitmap_set_bit (worklist, i);
4460 while (!bitmap_empty_p (worklist))
4462 i = bitmap_first_set_bit (worklist);
4463 bitmap_clear_bit (worklist, i);
4464 t = SSA_NAME_DEF_STMT (ssa_name (i));
4466 /* PHI nodes are somewhat special in that each PHI alternative has
4467 data and control dependencies. All the statements feeding the
4468 PHI node's arguments are always necessary. */
4469 if (gimple_code (t) == GIMPLE_PHI)
4473 for (k = 0; k < gimple_phi_num_args (t); k++)
4475 tree arg = PHI_ARG_DEF (t, k);
4476 if (TREE_CODE (arg) == SSA_NAME)
4478 gimple n = mark_operand_necessary (arg);
4480 bitmap_set_bit (worklist, SSA_NAME_VERSION (arg));
4486 /* Propagate through the operands. Examine all the USE, VUSE and
4487 VDEF operands in this statement. Mark all the statements
4488 which feed this statement's uses as necessary. */
4492 /* The operands of VDEF expressions are also needed as they
4493 represent potential definitions that may reach this
4494 statement (VDEF operands allow us to follow def-def
4497 FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
4499 gimple n = mark_operand_necessary (use);
4501 bitmap_set_bit (worklist, SSA_NAME_VERSION (use));
4506 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
4508 t = SSA_NAME_DEF_STMT (ssa_name (i));
4509 if (!gimple_plf (t, NECESSARY))
4511 gimple_stmt_iterator gsi;
4513 if (dump_file && (dump_flags & TDF_DETAILS))
4515 fprintf (dump_file, "Removing unnecessary insertion:");
4516 print_gimple_stmt (dump_file, t, 0, 0);
4519 gsi = gsi_for_stmt (t);
4520 if (gimple_code (t) == GIMPLE_PHI)
4521 remove_phi_node (&gsi, true);
4524 gsi_remove (&gsi, true);
4529 BITMAP_FREE (worklist);
4532 /* Compute a reverse post-order in *POST_ORDER. If INCLUDE_ENTRY_EXIT is
4533 true, then then ENTRY_BLOCK and EXIT_BLOCK are included. Returns
4534 the number of visited blocks. */
4537 my_rev_post_order_compute (int *post_order, bool include_entry_exit)
4539 edge_iterator *stack;
4541 int post_order_num = 0;
4544 if (include_entry_exit)
4545 post_order[post_order_num++] = EXIT_BLOCK;
4547 /* Allocate stack for back-tracking up CFG. */
4548 stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
4551 /* Allocate bitmap to track nodes that have been visited. */
4552 visited = sbitmap_alloc (last_basic_block);
4554 /* None of the nodes in the CFG have been visited yet. */
4555 sbitmap_zero (visited);
4557 /* Push the last edge on to the stack. */
4558 stack[sp++] = ei_start (EXIT_BLOCK_PTR->preds);
4566 /* Look at the edge on the top of the stack. */
4568 src = ei_edge (ei)->src;
4569 dest = ei_edge (ei)->dest;
4571 /* Check if the edge destination has been visited yet. */
4572 if (src != ENTRY_BLOCK_PTR && ! TEST_BIT (visited, src->index))
4574 /* Mark that we have visited the destination. */
4575 SET_BIT (visited, src->index);
4577 if (EDGE_COUNT (src->preds) > 0)
4578 /* Since the DEST node has been visited for the first
4579 time, check its successors. */
4580 stack[sp++] = ei_start (src->preds);
4582 post_order[post_order_num++] = src->index;
4586 if (ei_one_before_end_p (ei) && dest != EXIT_BLOCK_PTR)
4587 post_order[post_order_num++] = dest->index;
4589 if (!ei_one_before_end_p (ei))
4590 ei_next (&stack[sp - 1]);
4596 if (include_entry_exit)
4597 post_order[post_order_num++] = ENTRY_BLOCK;
4600 sbitmap_free (visited);
4601 return post_order_num;
4605 /* Initialize data structures used by PRE. */
4608 init_pre (bool do_fre)
4612 next_expression_id = 1;
4614 VEC_safe_push (pre_expr, heap, expressions, NULL);
4615 value_expressions = VEC_alloc (bitmap_set_t, heap, get_max_value_id () + 1);
4616 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
4617 get_max_value_id() + 1);
4622 inserted_exprs = BITMAP_ALLOC (NULL);
4623 need_creation = NULL;
4624 pretemp = NULL_TREE;
4625 storetemp = NULL_TREE;
4626 prephitemp = NULL_TREE;
4628 connect_infinite_loops_to_exit ();
4629 memset (&pre_stats, 0, sizeof (pre_stats));
4632 postorder = XNEWVEC (int, n_basic_blocks - NUM_FIXED_BLOCKS);
4633 my_rev_post_order_compute (postorder, false);
4636 bb->aux = XCNEWVEC (struct bb_bitmap_sets, 1);
4638 calculate_dominance_info (CDI_POST_DOMINATORS);
4639 calculate_dominance_info (CDI_DOMINATORS);
4641 bitmap_obstack_initialize (&grand_bitmap_obstack);
4642 phi_translate_table = htab_create (5110, expr_pred_trans_hash,
4643 expr_pred_trans_eq, free);
4644 expression_to_id = htab_create (num_ssa_names * 3,
4647 bitmap_set_pool = create_alloc_pool ("Bitmap sets",
4648 sizeof (struct bitmap_set), 30);
4649 pre_expr_pool = create_alloc_pool ("pre_expr nodes",
4650 sizeof (struct pre_expr_d), 30);
4653 EXP_GEN (bb) = bitmap_set_new ();
4654 PHI_GEN (bb) = bitmap_set_new ();
4655 TMP_GEN (bb) = bitmap_set_new ();
4656 AVAIL_OUT (bb) = bitmap_set_new ();
4659 need_eh_cleanup = BITMAP_ALLOC (NULL);
4663 /* Deallocate data structures used by PRE. */
4666 fini_pre (bool do_fre)
4671 VEC_free (bitmap_set_t, heap, value_expressions);
4672 BITMAP_FREE (inserted_exprs);
4673 VEC_free (gimple, heap, need_creation);
4674 bitmap_obstack_release (&grand_bitmap_obstack);
4675 free_alloc_pool (bitmap_set_pool);
4676 free_alloc_pool (pre_expr_pool);
4677 htab_delete (phi_translate_table);
4678 htab_delete (expression_to_id);
4679 VEC_free (unsigned, heap, name_to_id);
4687 free_dominance_info (CDI_POST_DOMINATORS);
4689 if (!bitmap_empty_p (need_eh_cleanup))
4691 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
4692 cleanup_tree_cfg ();
4695 BITMAP_FREE (need_eh_cleanup);
4698 loop_optimizer_finalize ();
4701 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4702 only wants to do full redundancy elimination. */
4705 execute_pre (bool do_fre)
4707 unsigned int todo = 0;
4709 do_partial_partial = optimize > 2 && optimize_function_for_speed_p (cfun);
4711 /* This has to happen before SCCVN runs because
4712 loop_optimizer_init may create new phis, etc. */
4714 loop_optimizer_init (LOOPS_NORMAL);
4716 if (!run_scc_vn (do_fre))
4719 loop_optimizer_finalize ();
4727 /* Collect and value number expressions computed in each basic block. */
4730 if (dump_file && (dump_flags & TDF_DETAILS))
4736 print_bitmap_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
4737 print_bitmap_set (dump_file, PHI_GEN (bb), "phi_gen", bb->index);
4738 print_bitmap_set (dump_file, TMP_GEN (bb), "tmp_gen", bb->index);
4739 print_bitmap_set (dump_file, AVAIL_OUT (bb), "avail_out", bb->index);
4743 /* Insert can get quite slow on an incredibly large number of basic
4744 blocks due to some quadratic behavior. Until this behavior is
4745 fixed, don't run it when he have an incredibly large number of
4746 bb's. If we aren't going to run insert, there is no point in
4747 computing ANTIC, either, even though it's plenty fast. */
4748 if (!do_fre && n_basic_blocks < 4000)
4754 /* Make sure to remove fake edges before committing our inserts.
4755 This makes sure we don't end up with extra critical edges that
4756 we would need to split. */
4757 remove_fake_exit_edges ();
4758 gsi_commit_edge_inserts ();
4760 /* Remove all the redundant expressions. */
4761 todo |= eliminate ();
4763 statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
4764 statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
4765 statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
4766 statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);
4767 statistics_counter_event (cfun, "Constified", pre_stats.constified);
4769 clear_expression_ids ();
4772 remove_dead_inserted_code ();
4780 /* Gate and execute functions for PRE. */
4785 return execute_pre (false);
4791 return flag_tree_pre != 0;
4794 struct gimple_opt_pass pass_pre =
4799 gate_pre, /* gate */
4800 do_pre, /* execute */
4803 0, /* static_pass_number */
4804 TV_TREE_PRE, /* tv_id */
4805 PROP_no_crit_edges | PROP_cfg
4806 | PROP_ssa, /* properties_required */
4807 0, /* properties_provided */
4808 0, /* properties_destroyed */
4809 TODO_rebuild_alias, /* todo_flags_start */
4810 TODO_update_ssa_only_virtuals | TODO_dump_func | TODO_ggc_collect
4811 | TODO_verify_ssa /* todo_flags_finish */
4816 /* Gate and execute functions for FRE. */
4821 return execute_pre (true);
4827 return flag_tree_fre != 0;
4830 struct gimple_opt_pass pass_fre =
4835 gate_fre, /* gate */
4836 execute_fre, /* execute */
4839 0, /* static_pass_number */
4840 TV_TREE_FRE, /* tv_id */
4841 PROP_cfg | PROP_ssa, /* properties_required */
4842 0, /* properties_provided */
4843 0, /* properties_destroyed */
4844 0, /* todo_flags_start */
4845 TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */