1 /* SCC value numbering for trees
2 Copyright (C) 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
27 #include "basic-block.h"
28 #include "tree-pretty-print.h"
29 #include "gimple-pretty-print.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"
39 #include "tree-pass.h"
42 #include "langhooks.h"
45 #include "tree-ssa-propagate.h"
46 #include "tree-ssa-sccvn.h"
48 /* This algorithm is based on the SCC algorithm presented by Keith
49 Cooper and L. Taylor Simpson in "SCC-Based Value numbering"
50 (http://citeseer.ist.psu.edu/41805.html). In
51 straight line code, it is equivalent to a regular hash based value
52 numbering that is performed in reverse postorder.
54 For code with cycles, there are two alternatives, both of which
55 require keeping the hashtables separate from the actual list of
56 value numbers for SSA names.
58 1. Iterate value numbering in an RPO walk of the blocks, removing
59 all the entries from the hashtable after each iteration (but
60 keeping the SSA name->value number mapping between iterations).
61 Iterate until it does not change.
63 2. Perform value numbering as part of an SCC walk on the SSA graph,
64 iterating only the cycles in the SSA graph until they do not change
65 (using a separate, optimistic hashtable for value numbering the SCC
68 The second is not just faster in practice (because most SSA graph
69 cycles do not involve all the variables in the graph), it also has
72 One of these nice properties is that when we pop an SCC off the
73 stack, we are guaranteed to have processed all the operands coming from
74 *outside of that SCC*, so we do not need to do anything special to
75 ensure they have value numbers.
77 Another nice property is that the SCC walk is done as part of a DFS
78 of the SSA graph, which makes it easy to perform combining and
79 simplifying operations at the same time.
81 The code below is deliberately written in a way that makes it easy
82 to separate the SCC walk from the other work it does.
84 In order to propagate constants through the code, we track which
85 expressions contain constants, and use those while folding. In
86 theory, we could also track expressions whose value numbers are
87 replaced, in case we end up folding based on expression
90 In order to value number memory, we assign value numbers to vuses.
91 This enables us to note that, for example, stores to the same
92 address of the same value from the same starting memory states are
96 1. We can iterate only the changing portions of the SCC's, but
97 I have not seen an SCC big enough for this to be a win.
98 2. If you differentiate between phi nodes for loops and phi nodes
99 for if-then-else, you can properly consider phi nodes in different
100 blocks for equivalence.
101 3. We could value number vuses in more cases, particularly, whole
105 /* The set of hashtables and alloc_pool's for their items. */
107 typedef struct vn_tables_s
112 struct obstack nary_obstack;
113 alloc_pool phis_pool;
114 alloc_pool references_pool;
117 static htab_t constant_to_value_id;
118 static bitmap constant_value_ids;
121 /* Valid hashtables storing information we have proven to be
124 static vn_tables_t valid_info;
126 /* Optimistic hashtables storing information we are making assumptions about
127 during iterations. */
129 static vn_tables_t optimistic_info;
131 /* Pointer to the set of hashtables that is currently being used.
132 Should always point to either the optimistic_info, or the
135 static vn_tables_t current_info;
138 /* Reverse post order index for each basic block. */
140 static int *rpo_numbers;
142 #define SSA_VAL(x) (VN_INFO ((x))->valnum)
144 /* This represents the top of the VN lattice, which is the universal
149 /* Unique counter for our value ids. */
151 static unsigned int next_value_id;
153 /* Next DFS number and the stack for strongly connected component
156 static unsigned int next_dfs_num;
157 static VEC (tree, heap) *sccstack;
160 DEF_VEC_P(vn_ssa_aux_t);
161 DEF_VEC_ALLOC_P(vn_ssa_aux_t, heap);
163 /* Table of vn_ssa_aux_t's, one per ssa_name. The vn_ssa_aux_t objects
164 are allocated on an obstack for locality reasons, and to free them
165 without looping over the VEC. */
167 static VEC (vn_ssa_aux_t, heap) *vn_ssa_aux_table;
168 static struct obstack vn_ssa_aux_obstack;
170 /* Return the value numbering information for a given SSA name. */
175 vn_ssa_aux_t res = VEC_index (vn_ssa_aux_t, vn_ssa_aux_table,
176 SSA_NAME_VERSION (name));
177 gcc_checking_assert (res);
181 /* Set the value numbering info for a given SSA name to a given
185 VN_INFO_SET (tree name, vn_ssa_aux_t value)
187 VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
188 SSA_NAME_VERSION (name), value);
191 /* Initialize the value numbering info for a given SSA name.
192 This should be called just once for every SSA name. */
195 VN_INFO_GET (tree name)
197 vn_ssa_aux_t newinfo;
199 newinfo = XOBNEW (&vn_ssa_aux_obstack, struct vn_ssa_aux);
200 memset (newinfo, 0, sizeof (struct vn_ssa_aux));
201 if (SSA_NAME_VERSION (name) >= VEC_length (vn_ssa_aux_t, vn_ssa_aux_table))
202 VEC_safe_grow (vn_ssa_aux_t, heap, vn_ssa_aux_table,
203 SSA_NAME_VERSION (name) + 1);
204 VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
205 SSA_NAME_VERSION (name), newinfo);
210 /* Get the representative expression for the SSA_NAME NAME. Returns
211 the representative SSA_NAME if there is no expression associated with it. */
214 vn_get_expr_for (tree name)
216 vn_ssa_aux_t vn = VN_INFO (name);
218 tree expr = NULL_TREE;
220 if (vn->valnum == VN_TOP)
223 /* If the value-number is a constant it is the representative
225 if (TREE_CODE (vn->valnum) != SSA_NAME)
228 /* Get to the information of the value of this SSA_NAME. */
229 vn = VN_INFO (vn->valnum);
231 /* If the value-number is a constant it is the representative
233 if (TREE_CODE (vn->valnum) != SSA_NAME)
236 /* Else if we have an expression, return it. */
237 if (vn->expr != NULL_TREE)
240 /* Otherwise use the defining statement to build the expression. */
241 def_stmt = SSA_NAME_DEF_STMT (vn->valnum);
243 /* If the value number is a default-definition or a PHI result
245 if (gimple_nop_p (def_stmt)
246 || gimple_code (def_stmt) == GIMPLE_PHI)
249 if (!is_gimple_assign (def_stmt))
252 /* FIXME tuples. This is incomplete and likely will miss some
254 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)))
257 if ((gimple_assign_rhs_code (def_stmt) == VIEW_CONVERT_EXPR
258 || gimple_assign_rhs_code (def_stmt) == REALPART_EXPR
259 || gimple_assign_rhs_code (def_stmt) == IMAGPART_EXPR)
260 && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME)
261 expr = fold_build1 (gimple_assign_rhs_code (def_stmt),
262 gimple_expr_type (def_stmt),
263 TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0));
267 expr = fold_build1 (gimple_assign_rhs_code (def_stmt),
268 gimple_expr_type (def_stmt),
269 gimple_assign_rhs1 (def_stmt));
273 expr = fold_build2 (gimple_assign_rhs_code (def_stmt),
274 gimple_expr_type (def_stmt),
275 gimple_assign_rhs1 (def_stmt),
276 gimple_assign_rhs2 (def_stmt));
281 if (expr == NULL_TREE)
284 /* Cache the expression. */
291 /* Free a phi operation structure VP. */
296 vn_phi_t phi = (vn_phi_t) vp;
297 VEC_free (tree, heap, phi->phiargs);
300 /* Free a reference operation structure VP. */
303 free_reference (void *vp)
305 vn_reference_t vr = (vn_reference_t) vp;
306 VEC_free (vn_reference_op_s, heap, vr->operands);
309 /* Hash table equality function for vn_constant_t. */
312 vn_constant_eq (const void *p1, const void *p2)
314 const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
315 const struct vn_constant_s *vc2 = (const struct vn_constant_s *) p2;
317 if (vc1->hashcode != vc2->hashcode)
320 return vn_constant_eq_with_type (vc1->constant, vc2->constant);
323 /* Hash table hash function for vn_constant_t. */
326 vn_constant_hash (const void *p1)
328 const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
329 return vc1->hashcode;
332 /* Lookup a value id for CONSTANT and return it. If it does not
336 get_constant_value_id (tree constant)
339 struct vn_constant_s vc;
341 vc.hashcode = vn_hash_constant_with_type (constant);
342 vc.constant = constant;
343 slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
344 vc.hashcode, NO_INSERT);
346 return ((vn_constant_t)*slot)->value_id;
350 /* Lookup a value id for CONSTANT, and if it does not exist, create a
351 new one and return it. If it does exist, return it. */
354 get_or_alloc_constant_value_id (tree constant)
357 struct vn_constant_s vc;
360 vc.hashcode = vn_hash_constant_with_type (constant);
361 vc.constant = constant;
362 slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
363 vc.hashcode, INSERT);
365 return ((vn_constant_t)*slot)->value_id;
367 vcp = XNEW (struct vn_constant_s);
368 vcp->hashcode = vc.hashcode;
369 vcp->constant = constant;
370 vcp->value_id = get_next_value_id ();
371 *slot = (void *) vcp;
372 bitmap_set_bit (constant_value_ids, vcp->value_id);
373 return vcp->value_id;
376 /* Return true if V is a value id for a constant. */
379 value_id_constant_p (unsigned int v)
381 return bitmap_bit_p (constant_value_ids, v);
384 /* Compare two reference operands P1 and P2 for equality. Return true if
385 they are equal, and false otherwise. */
388 vn_reference_op_eq (const void *p1, const void *p2)
390 const_vn_reference_op_t const vro1 = (const_vn_reference_op_t) p1;
391 const_vn_reference_op_t const vro2 = (const_vn_reference_op_t) p2;
393 return vro1->opcode == vro2->opcode
394 && types_compatible_p (vro1->type, vro2->type)
395 && expressions_equal_p (vro1->op0, vro2->op0)
396 && expressions_equal_p (vro1->op1, vro2->op1)
397 && expressions_equal_p (vro1->op2, vro2->op2);
400 /* Compute the hash for a reference operand VRO1. */
403 vn_reference_op_compute_hash (const vn_reference_op_t vro1, hashval_t result)
405 result = iterative_hash_hashval_t (vro1->opcode, result);
407 result = iterative_hash_expr (vro1->op0, result);
409 result = iterative_hash_expr (vro1->op1, result);
411 result = iterative_hash_expr (vro1->op2, result);
415 /* Return the hashcode for a given reference operation P1. */
418 vn_reference_hash (const void *p1)
420 const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
421 return vr1->hashcode;
424 /* Compute a hash for the reference operation VR1 and return it. */
427 vn_reference_compute_hash (const vn_reference_t vr1)
429 hashval_t result = 0;
431 vn_reference_op_t vro;
432 HOST_WIDE_INT off = -1;
435 FOR_EACH_VEC_ELT (vn_reference_op_s, vr1->operands, i, vro)
437 if (vro->opcode == MEM_REF)
439 else if (vro->opcode != ADDR_EXPR)
451 result = iterative_hash_hashval_t (off, result);
454 && vro->opcode == ADDR_EXPR)
458 tree op = TREE_OPERAND (vro->op0, 0);
459 result = iterative_hash_hashval_t (TREE_CODE (op), result);
460 result = iterative_hash_expr (op, result);
464 result = vn_reference_op_compute_hash (vro, result);
468 result += SSA_NAME_VERSION (vr1->vuse);
473 /* Return true if reference operations P1 and P2 are equivalent. This
474 means they have the same set of operands and vuses. */
477 vn_reference_eq (const void *p1, const void *p2)
481 const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
482 const_vn_reference_t const vr2 = (const_vn_reference_t) p2;
483 if (vr1->hashcode != vr2->hashcode)
486 /* Early out if this is not a hash collision. */
487 if (vr1->hashcode != vr2->hashcode)
490 /* The VOP needs to be the same. */
491 if (vr1->vuse != vr2->vuse)
494 /* If the operands are the same we are done. */
495 if (vr1->operands == vr2->operands)
498 if (!expressions_equal_p (TYPE_SIZE (vr1->type), TYPE_SIZE (vr2->type)))
501 if (INTEGRAL_TYPE_P (vr1->type)
502 && INTEGRAL_TYPE_P (vr2->type))
504 if (TYPE_PRECISION (vr1->type) != TYPE_PRECISION (vr2->type))
507 else if (INTEGRAL_TYPE_P (vr1->type)
508 && (TYPE_PRECISION (vr1->type)
509 != TREE_INT_CST_LOW (TYPE_SIZE (vr1->type))))
511 else if (INTEGRAL_TYPE_P (vr2->type)
512 && (TYPE_PRECISION (vr2->type)
513 != TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
520 HOST_WIDE_INT off1 = 0, off2 = 0;
521 vn_reference_op_t vro1, vro2;
522 vn_reference_op_s tem1, tem2;
523 bool deref1 = false, deref2 = false;
524 for (; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro1); i++)
526 if (vro1->opcode == MEM_REF)
532 for (; VEC_iterate (vn_reference_op_s, vr2->operands, j, vro2); j++)
534 if (vro2->opcode == MEM_REF)
542 if (deref1 && vro1->opcode == ADDR_EXPR)
544 memset (&tem1, 0, sizeof (tem1));
545 tem1.op0 = TREE_OPERAND (vro1->op0, 0);
546 tem1.type = TREE_TYPE (tem1.op0);
547 tem1.opcode = TREE_CODE (tem1.op0);
550 if (deref2 && vro2->opcode == ADDR_EXPR)
552 memset (&tem2, 0, sizeof (tem2));
553 tem2.op0 = TREE_OPERAND (vro2->op0, 0);
554 tem2.type = TREE_TYPE (tem2.op0);
555 tem2.opcode = TREE_CODE (tem2.op0);
558 if (!vn_reference_op_eq (vro1, vro2))
563 while (VEC_length (vn_reference_op_s, vr1->operands) != i
564 || VEC_length (vn_reference_op_s, vr2->operands) != j);
569 /* Copy the operations present in load/store REF into RESULT, a vector of
570 vn_reference_op_s's. */
573 copy_reference_ops_from_ref (tree ref, VEC(vn_reference_op_s, heap) **result)
575 if (TREE_CODE (ref) == TARGET_MEM_REF)
577 vn_reference_op_s temp;
579 memset (&temp, 0, sizeof (temp));
580 /* We do not care for spurious type qualifications. */
581 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
582 temp.opcode = TREE_CODE (ref);
583 temp.op0 = TMR_INDEX (ref);
584 temp.op1 = TMR_STEP (ref);
585 temp.op2 = TMR_OFFSET (ref);
587 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
589 memset (&temp, 0, sizeof (temp));
590 temp.type = NULL_TREE;
591 temp.opcode = ERROR_MARK;
592 temp.op0 = TMR_INDEX2 (ref);
594 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
596 memset (&temp, 0, sizeof (temp));
597 temp.type = NULL_TREE;
598 temp.opcode = TREE_CODE (TMR_BASE (ref));
599 temp.op0 = TMR_BASE (ref);
601 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
605 /* For non-calls, store the information that makes up the address. */
609 vn_reference_op_s temp;
611 memset (&temp, 0, sizeof (temp));
612 /* We do not care for spurious type qualifications. */
613 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
614 temp.opcode = TREE_CODE (ref);
620 /* The base address gets its own vn_reference_op_s structure. */
621 temp.op0 = TREE_OPERAND (ref, 1);
622 if (host_integerp (TREE_OPERAND (ref, 1), 0))
623 temp.off = TREE_INT_CST_LOW (TREE_OPERAND (ref, 1));
626 /* Record bits and position. */
627 temp.op0 = TREE_OPERAND (ref, 1);
628 temp.op1 = TREE_OPERAND (ref, 2);
631 /* The field decl is enough to unambiguously specify the field,
632 a matching type is not necessary and a mismatching type
633 is always a spurious difference. */
634 temp.type = NULL_TREE;
635 temp.op0 = TREE_OPERAND (ref, 1);
636 temp.op1 = TREE_OPERAND (ref, 2);
638 tree this_offset = component_ref_field_offset (ref);
640 && TREE_CODE (this_offset) == INTEGER_CST)
642 tree bit_offset = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1));
643 if (TREE_INT_CST_LOW (bit_offset) % BITS_PER_UNIT == 0)
646 = double_int_add (tree_to_double_int (this_offset),
648 (tree_to_double_int (bit_offset),
649 uhwi_to_double_int (BITS_PER_UNIT),
651 if (double_int_fits_in_shwi_p (off))
657 case ARRAY_RANGE_REF:
659 /* Record index as operand. */
660 temp.op0 = TREE_OPERAND (ref, 1);
661 /* Always record lower bounds and element size. */
662 temp.op1 = array_ref_low_bound (ref);
663 temp.op2 = array_ref_element_size (ref);
664 if (TREE_CODE (temp.op0) == INTEGER_CST
665 && TREE_CODE (temp.op1) == INTEGER_CST
666 && TREE_CODE (temp.op2) == INTEGER_CST)
668 double_int off = tree_to_double_int (temp.op0);
669 off = double_int_add (off,
671 (tree_to_double_int (temp.op1)));
672 off = double_int_mul (off, tree_to_double_int (temp.op2));
673 if (double_int_fits_in_shwi_p (off))
691 if (is_gimple_min_invariant (ref))
697 /* These are only interesting for their operands, their
698 existence, and their type. They will never be the last
699 ref in the chain of references (IE they require an
700 operand), so we don't have to put anything
701 for op* as it will be handled by the iteration */
703 case VIEW_CONVERT_EXPR:
707 /* This is only interesting for its constant offset. */
708 temp.off = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (ref)));
713 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
715 if (REFERENCE_CLASS_P (ref)
716 || (TREE_CODE (ref) == ADDR_EXPR
717 && !is_gimple_min_invariant (ref)))
718 ref = TREE_OPERAND (ref, 0);
724 /* Build a alias-oracle reference abstraction in *REF from the vn_reference
725 operands in *OPS, the reference alias set SET and the reference type TYPE.
726 Return true if something useful was produced. */
729 ao_ref_init_from_vn_reference (ao_ref *ref,
730 alias_set_type set, tree type,
731 VEC (vn_reference_op_s, heap) *ops)
733 vn_reference_op_t op;
735 tree base = NULL_TREE;
737 HOST_WIDE_INT offset = 0;
738 HOST_WIDE_INT max_size;
739 HOST_WIDE_INT size = -1;
740 tree size_tree = NULL_TREE;
741 alias_set_type base_alias_set = -1;
743 /* First get the final access size from just the outermost expression. */
744 op = VEC_index (vn_reference_op_s, ops, 0);
745 if (op->opcode == COMPONENT_REF)
746 size_tree = DECL_SIZE (op->op0);
747 else if (op->opcode == BIT_FIELD_REF)
751 enum machine_mode mode = TYPE_MODE (type);
753 size_tree = TYPE_SIZE (type);
755 size = GET_MODE_BITSIZE (mode);
757 if (size_tree != NULL_TREE)
759 if (!host_integerp (size_tree, 1))
762 size = TREE_INT_CST_LOW (size_tree);
765 /* Initially, maxsize is the same as the accessed element size.
766 In the following it will only grow (or become -1). */
769 /* Compute cumulative bit-offset for nested component-refs and array-refs,
770 and find the ultimate containing object. */
771 FOR_EACH_VEC_ELT (vn_reference_op_s, ops, i, op)
775 /* These may be in the reference ops, but we cannot do anything
776 sensible with them here. */
778 /* Apart from ADDR_EXPR arguments to MEM_REF. */
779 if (base != NULL_TREE
780 && TREE_CODE (base) == MEM_REF
782 && DECL_P (TREE_OPERAND (op->op0, 0)))
784 vn_reference_op_t pop = VEC_index (vn_reference_op_s, ops, i-1);
785 base = TREE_OPERAND (op->op0, 0);
792 offset += pop->off * BITS_PER_UNIT;
800 /* Record the base objects. */
802 base_alias_set = get_deref_alias_set (op->op0);
803 *op0_p = build2 (MEM_REF, op->type,
805 op0_p = &TREE_OPERAND (*op0_p, 0);
816 /* And now the usual component-reference style ops. */
818 offset += tree_low_cst (op->op1, 0);
823 tree field = op->op0;
824 /* We do not have a complete COMPONENT_REF tree here so we
825 cannot use component_ref_field_offset. Do the interesting
829 || !host_integerp (DECL_FIELD_OFFSET (field), 1))
833 offset += (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (field))
835 offset += TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
840 case ARRAY_RANGE_REF:
842 /* We recorded the lower bound and the element size. */
843 if (!host_integerp (op->op0, 0)
844 || !host_integerp (op->op1, 0)
845 || !host_integerp (op->op2, 0))
849 HOST_WIDE_INT hindex = TREE_INT_CST_LOW (op->op0);
850 hindex -= TREE_INT_CST_LOW (op->op1);
851 hindex *= TREE_INT_CST_LOW (op->op2);
852 hindex *= BITS_PER_UNIT;
864 case VIEW_CONVERT_EXPR:
881 if (base == NULL_TREE)
884 ref->ref = NULL_TREE;
886 ref->offset = offset;
888 ref->max_size = max_size;
889 ref->ref_alias_set = set;
890 if (base_alias_set != -1)
891 ref->base_alias_set = base_alias_set;
893 ref->base_alias_set = get_alias_set (base);
898 /* Copy the operations present in load/store/call REF into RESULT, a vector of
899 vn_reference_op_s's. */
902 copy_reference_ops_from_call (gimple call,
903 VEC(vn_reference_op_s, heap) **result)
905 vn_reference_op_s temp;
908 /* Copy the type, opcode, function being called and static chain. */
909 memset (&temp, 0, sizeof (temp));
910 temp.type = gimple_call_return_type (call);
911 temp.opcode = CALL_EXPR;
912 temp.op0 = gimple_call_fn (call);
913 temp.op1 = gimple_call_chain (call);
915 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
917 /* Copy the call arguments. As they can be references as well,
918 just chain them together. */
919 for (i = 0; i < gimple_call_num_args (call); ++i)
921 tree callarg = gimple_call_arg (call, i);
922 copy_reference_ops_from_ref (callarg, result);
926 /* Create a vector of vn_reference_op_s structures from REF, a
927 REFERENCE_CLASS_P tree. The vector is not shared. */
929 static VEC(vn_reference_op_s, heap) *
930 create_reference_ops_from_ref (tree ref)
932 VEC (vn_reference_op_s, heap) *result = NULL;
934 copy_reference_ops_from_ref (ref, &result);
938 /* Create a vector of vn_reference_op_s structures from CALL, a
939 call statement. The vector is not shared. */
941 static VEC(vn_reference_op_s, heap) *
942 create_reference_ops_from_call (gimple call)
944 VEC (vn_reference_op_s, heap) *result = NULL;
946 copy_reference_ops_from_call (call, &result);
950 /* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
951 *I_P to point to the last element of the replacement. */
953 vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **ops,
956 unsigned int i = *i_p;
957 vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
958 vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
960 HOST_WIDE_INT addr_offset;
962 /* The only thing we have to do is from &OBJ.foo.bar add the offset
963 from .foo.bar to the preceeding MEM_REF offset and replace the
964 address with &OBJ. */
965 addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (op->op0, 0),
967 gcc_checking_assert (addr_base && TREE_CODE (addr_base) != MEM_REF);
968 if (addr_base != op->op0)
970 double_int off = tree_to_double_int (mem_op->op0);
971 off = double_int_sext (off, TYPE_PRECISION (TREE_TYPE (mem_op->op0)));
972 off = double_int_add (off, shwi_to_double_int (addr_offset));
973 mem_op->op0 = double_int_to_tree (TREE_TYPE (mem_op->op0), off);
974 op->op0 = build_fold_addr_expr (addr_base);
975 if (host_integerp (mem_op->op0, 0))
976 mem_op->off = TREE_INT_CST_LOW (mem_op->op0);
982 /* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
983 *I_P to point to the last element of the replacement. */
985 vn_reference_maybe_forwprop_address (VEC (vn_reference_op_s, heap) **ops,
988 unsigned int i = *i_p;
989 vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
990 vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
995 def_stmt = SSA_NAME_DEF_STMT (op->op0);
996 if (!is_gimple_assign (def_stmt))
999 code = gimple_assign_rhs_code (def_stmt);
1000 if (code != ADDR_EXPR
1001 && code != POINTER_PLUS_EXPR)
1004 off = tree_to_double_int (mem_op->op0);
1005 off = double_int_sext (off, TYPE_PRECISION (TREE_TYPE (mem_op->op0)));
1007 /* The only thing we have to do is from &OBJ.foo.bar add the offset
1008 from .foo.bar to the preceeding MEM_REF offset and replace the
1009 address with &OBJ. */
1010 if (code == ADDR_EXPR)
1012 tree addr, addr_base;
1013 HOST_WIDE_INT addr_offset;
1015 addr = gimple_assign_rhs1 (def_stmt);
1016 addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (addr, 0),
1019 || TREE_CODE (addr_base) != MEM_REF)
1022 off = double_int_add (off, shwi_to_double_int (addr_offset));
1023 off = double_int_add (off, mem_ref_offset (addr_base));
1024 op->op0 = TREE_OPERAND (addr_base, 0);
1029 ptr = gimple_assign_rhs1 (def_stmt);
1030 ptroff = gimple_assign_rhs2 (def_stmt);
1031 if (TREE_CODE (ptr) != SSA_NAME
1032 || TREE_CODE (ptroff) != INTEGER_CST)
1035 off = double_int_add (off, tree_to_double_int (ptroff));
1039 mem_op->op0 = double_int_to_tree (TREE_TYPE (mem_op->op0), off);
1040 if (host_integerp (mem_op->op0, 0))
1041 mem_op->off = TREE_INT_CST_LOW (mem_op->op0);
1044 if (TREE_CODE (op->op0) == SSA_NAME)
1045 op->op0 = SSA_VAL (op->op0);
1046 if (TREE_CODE (op->op0) != SSA_NAME)
1047 op->opcode = TREE_CODE (op->op0);
1050 if (TREE_CODE (op->op0) == SSA_NAME)
1051 vn_reference_maybe_forwprop_address (ops, i_p);
1052 else if (TREE_CODE (op->op0) == ADDR_EXPR)
1053 vn_reference_fold_indirect (ops, i_p);
1056 /* Optimize the reference REF to a constant if possible or return
1057 NULL_TREE if not. */
1060 fully_constant_vn_reference_p (vn_reference_t ref)
1062 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1063 vn_reference_op_t op;
1065 /* Try to simplify the translated expression if it is
1066 a call to a builtin function with at most two arguments. */
1067 op = VEC_index (vn_reference_op_s, operands, 0);
1068 if (op->opcode == CALL_EXPR
1069 && TREE_CODE (op->op0) == ADDR_EXPR
1070 && TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
1071 && DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
1072 && VEC_length (vn_reference_op_s, operands) >= 2
1073 && VEC_length (vn_reference_op_s, operands) <= 3)
1075 vn_reference_op_t arg0, arg1 = NULL;
1076 bool anyconst = false;
1077 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1078 if (VEC_length (vn_reference_op_s, operands) > 2)
1079 arg1 = VEC_index (vn_reference_op_s, operands, 2);
1080 if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
1081 || (arg0->opcode == ADDR_EXPR
1082 && is_gimple_min_invariant (arg0->op0)))
1085 && (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
1086 || (arg1->opcode == ADDR_EXPR
1087 && is_gimple_min_invariant (arg1->op0))))
1091 tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
1094 arg1 ? arg1->op0 : NULL);
1096 && TREE_CODE (folded) == NOP_EXPR)
1097 folded = TREE_OPERAND (folded, 0);
1099 && is_gimple_min_invariant (folded))
1104 /* Simplify reads from constant strings. */
1105 else if (op->opcode == ARRAY_REF
1106 && TREE_CODE (op->op0) == INTEGER_CST
1107 && integer_zerop (op->op1)
1108 && VEC_length (vn_reference_op_s, operands) == 2)
1110 vn_reference_op_t arg0;
1111 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1112 if (arg0->opcode == STRING_CST
1113 && (TYPE_MODE (op->type)
1114 == TYPE_MODE (TREE_TYPE (TREE_TYPE (arg0->op0))))
1115 && GET_MODE_CLASS (TYPE_MODE (op->type)) == MODE_INT
1116 && GET_MODE_SIZE (TYPE_MODE (op->type)) == 1
1117 && compare_tree_int (op->op0, TREE_STRING_LENGTH (arg0->op0)) < 0)
1118 return build_int_cst_type (op->type,
1119 (TREE_STRING_POINTER (arg0->op0)
1120 [TREE_INT_CST_LOW (op->op0)]));
1126 /* Transform any SSA_NAME's in a vector of vn_reference_op_s
1127 structures into their value numbers. This is done in-place, and
1128 the vector passed in is returned. */
1130 static VEC (vn_reference_op_s, heap) *
1131 valueize_refs (VEC (vn_reference_op_s, heap) *orig)
1133 vn_reference_op_t vro;
1136 FOR_EACH_VEC_ELT (vn_reference_op_s, orig, i, vro)
1138 if (vro->opcode == SSA_NAME
1139 || (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME))
1141 vro->op0 = SSA_VAL (vro->op0);
1142 /* If it transforms from an SSA_NAME to a constant, update
1144 if (TREE_CODE (vro->op0) != SSA_NAME && vro->opcode == SSA_NAME)
1145 vro->opcode = TREE_CODE (vro->op0);
1147 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1148 vro->op1 = SSA_VAL (vro->op1);
1149 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
1150 vro->op2 = SSA_VAL (vro->op2);
1151 /* If it transforms from an SSA_NAME to an address, fold with
1152 a preceding indirect reference. */
1155 && TREE_CODE (vro->op0) == ADDR_EXPR
1156 && VEC_index (vn_reference_op_s,
1157 orig, i - 1)->opcode == MEM_REF)
1158 vn_reference_fold_indirect (&orig, &i);
1160 && vro->opcode == SSA_NAME
1161 && VEC_index (vn_reference_op_s,
1162 orig, i - 1)->opcode == MEM_REF)
1163 vn_reference_maybe_forwprop_address (&orig, &i);
1164 /* If it transforms a non-constant ARRAY_REF into a constant
1165 one, adjust the constant offset. */
1166 else if (vro->opcode == ARRAY_REF
1168 && TREE_CODE (vro->op0) == INTEGER_CST
1169 && TREE_CODE (vro->op1) == INTEGER_CST
1170 && TREE_CODE (vro->op2) == INTEGER_CST)
1172 double_int off = tree_to_double_int (vro->op0);
1173 off = double_int_add (off,
1175 (tree_to_double_int (vro->op1)));
1176 off = double_int_mul (off, tree_to_double_int (vro->op2));
1177 if (double_int_fits_in_shwi_p (off))
1185 static VEC(vn_reference_op_s, heap) *shared_lookup_references;
1187 /* Create a vector of vn_reference_op_s structures from REF, a
1188 REFERENCE_CLASS_P tree. The vector is shared among all callers of
1191 static VEC(vn_reference_op_s, heap) *
1192 valueize_shared_reference_ops_from_ref (tree ref)
1196 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1197 copy_reference_ops_from_ref (ref, &shared_lookup_references);
1198 shared_lookup_references = valueize_refs (shared_lookup_references);
1199 return shared_lookup_references;
1202 /* Create a vector of vn_reference_op_s structures from CALL, a
1203 call statement. The vector is shared among all callers of
1206 static VEC(vn_reference_op_s, heap) *
1207 valueize_shared_reference_ops_from_call (gimple call)
1211 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1212 copy_reference_ops_from_call (call, &shared_lookup_references);
1213 shared_lookup_references = valueize_refs (shared_lookup_references);
1214 return shared_lookup_references;
1217 /* Lookup a SCCVN reference operation VR in the current hash table.
1218 Returns the resulting value number if it exists in the hash table,
1219 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1220 vn_reference_t stored in the hashtable if something is found. */
1223 vn_reference_lookup_1 (vn_reference_t vr, vn_reference_t *vnresult)
1228 hash = vr->hashcode;
1229 slot = htab_find_slot_with_hash (current_info->references, vr,
1231 if (!slot && current_info == optimistic_info)
1232 slot = htab_find_slot_with_hash (valid_info->references, vr,
1237 *vnresult = (vn_reference_t)*slot;
1238 return ((vn_reference_t)*slot)->result;
1244 static tree *last_vuse_ptr;
1246 /* Callback for walk_non_aliased_vuses. Adjusts the vn_reference_t VR_
1247 with the current VUSE and performs the expression lookup. */
1250 vn_reference_lookup_2 (ao_ref *op ATTRIBUTE_UNUSED, tree vuse, void *vr_)
1252 vn_reference_t vr = (vn_reference_t)vr_;
1257 *last_vuse_ptr = vuse;
1259 /* Fixup vuse and hash. */
1261 vr->hashcode = vr->hashcode - SSA_NAME_VERSION (vr->vuse);
1262 vr->vuse = SSA_VAL (vuse);
1264 vr->hashcode = vr->hashcode + SSA_NAME_VERSION (vr->vuse);
1266 hash = vr->hashcode;
1267 slot = htab_find_slot_with_hash (current_info->references, vr,
1269 if (!slot && current_info == optimistic_info)
1270 slot = htab_find_slot_with_hash (valid_info->references, vr,
1278 /* Callback for walk_non_aliased_vuses. Tries to perform a lookup
1279 from the statement defining VUSE and if not successful tries to
1280 translate *REFP and VR_ through an aggregate copy at the defintion
1284 vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
1286 vn_reference_t vr = (vn_reference_t)vr_;
1287 gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
1290 HOST_WIDE_INT offset, maxsize;
1292 /* First try to disambiguate after value-replacing in the definitions LHS. */
1293 if (is_gimple_assign (def_stmt))
1295 tree lhs = gimple_assign_lhs (def_stmt);
1297 VEC (vn_reference_op_s, heap) *operands = NULL;
1299 copy_reference_ops_from_ref (lhs, &operands);
1300 operands = valueize_refs (operands);
1301 if (ao_ref_init_from_vn_reference (&ref1, get_alias_set (lhs),
1302 TREE_TYPE (lhs), operands))
1303 res = refs_may_alias_p_1 (ref, &ref1, true);
1304 VEC_free (vn_reference_op_s, heap, operands);
1309 base = ao_ref_base (ref);
1310 offset = ref->offset;
1311 maxsize = ref->max_size;
1313 /* If we cannot constrain the size of the reference we cannot
1314 test if anything kills it. */
1318 /* def_stmt may-defs *ref. See if we can derive a value for *ref
1319 from that defintion.
1321 if (is_gimple_reg_type (vr->type)
1322 && is_gimple_call (def_stmt)
1323 && (fndecl = gimple_call_fndecl (def_stmt))
1324 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
1325 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET
1326 && integer_zerop (gimple_call_arg (def_stmt, 1))
1327 && host_integerp (gimple_call_arg (def_stmt, 2), 1)
1328 && TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR)
1330 tree ref2 = TREE_OPERAND (gimple_call_arg (def_stmt, 0), 0);
1332 HOST_WIDE_INT offset2, size2, maxsize2;
1333 base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &maxsize2);
1334 size2 = TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2)) * 8;
1335 if ((unsigned HOST_WIDE_INT)size2 / 8
1336 == TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2))
1337 && operand_equal_p (base, base2, 0)
1338 && offset2 <= offset
1339 && offset2 + size2 >= offset + maxsize)
1341 tree val = fold_convert (vr->type, integer_zero_node);
1342 unsigned int value_id = get_or_alloc_constant_value_id (val);
1343 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1344 VEC_copy (vn_reference_op_s,
1345 heap, vr->operands),
1350 /* 2) Assignment from an empty CONSTRUCTOR. */
1351 else if (is_gimple_reg_type (vr->type)
1352 && gimple_assign_single_p (def_stmt)
1353 && gimple_assign_rhs_code (def_stmt) == CONSTRUCTOR
1354 && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (def_stmt)) == 0)
1357 HOST_WIDE_INT offset2, size2, maxsize2;
1358 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1359 &offset2, &size2, &maxsize2);
1360 if (operand_equal_p (base, base2, 0)
1361 && offset2 <= offset
1362 && offset2 + size2 >= offset + maxsize)
1364 tree val = fold_convert (vr->type, integer_zero_node);
1365 unsigned int value_id = get_or_alloc_constant_value_id (val);
1366 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1367 VEC_copy (vn_reference_op_s,
1368 heap, vr->operands),
1373 /* For aggregate copies translate the reference through them if
1374 the copy kills ref. */
1375 else if (gimple_assign_single_p (def_stmt)
1376 && (DECL_P (gimple_assign_rhs1 (def_stmt))
1377 || TREE_CODE (gimple_assign_rhs1 (def_stmt)) == MEM_REF
1378 || handled_component_p (gimple_assign_rhs1 (def_stmt))))
1381 HOST_WIDE_INT offset2, size2, maxsize2;
1383 VEC (vn_reference_op_s, heap) *lhs = NULL, *rhs = NULL;
1384 vn_reference_op_t vro;
1387 /* See if the assignment kills REF. */
1388 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1389 &offset2, &size2, &maxsize2);
1390 if (!operand_equal_p (base, base2, 0)
1392 || offset2 + size2 < offset + maxsize)
1395 /* Find the common base of ref and the lhs. */
1396 copy_reference_ops_from_ref (gimple_assign_lhs (def_stmt), &lhs);
1397 i = VEC_length (vn_reference_op_s, vr->operands) - 1;
1398 j = VEC_length (vn_reference_op_s, lhs) - 1;
1399 while (j >= 0 && i >= 0
1400 && vn_reference_op_eq (VEC_index (vn_reference_op_s,
1402 VEC_index (vn_reference_op_s, lhs, j)))
1408 VEC_free (vn_reference_op_s, heap, lhs);
1409 /* i now points to the first additional op.
1410 ??? LHS may not be completely contained in VR, one or more
1411 VIEW_CONVERT_EXPRs could be in its way. We could at least
1412 try handling outermost VIEW_CONVERT_EXPRs. */
1416 /* Now re-write REF to be based on the rhs of the assignment. */
1417 copy_reference_ops_from_ref (gimple_assign_rhs1 (def_stmt), &rhs);
1418 /* We need to pre-pend vr->operands[0..i] to rhs. */
1419 if (i + 1 + VEC_length (vn_reference_op_s, rhs)
1420 > VEC_length (vn_reference_op_s, vr->operands))
1422 VEC (vn_reference_op_s, heap) *old = vr->operands;
1423 VEC_safe_grow (vn_reference_op_s, heap, vr->operands,
1424 i + 1 + VEC_length (vn_reference_op_s, rhs));
1425 if (old == shared_lookup_references
1426 && vr->operands != old)
1427 shared_lookup_references = NULL;
1430 VEC_truncate (vn_reference_op_s, vr->operands,
1431 i + 1 + VEC_length (vn_reference_op_s, rhs));
1432 FOR_EACH_VEC_ELT (vn_reference_op_s, rhs, j, vro)
1433 VEC_replace (vn_reference_op_s, vr->operands, i + 1 + j, vro);
1434 VEC_free (vn_reference_op_s, heap, rhs);
1435 vr->hashcode = vn_reference_compute_hash (vr);
1437 /* Adjust *ref from the new operands. */
1438 if (!ao_ref_init_from_vn_reference (&r, vr->set, vr->type, vr->operands))
1440 /* This can happen with bitfields. */
1441 if (ref->size != r.size)
1445 /* Do not update last seen VUSE after translating. */
1446 last_vuse_ptr = NULL;
1448 /* Keep looking for the adjusted *REF / VR pair. */
1452 /* Bail out and stop walking. */
1456 /* Lookup a reference operation by it's parts, in the current hash table.
1457 Returns the resulting value number if it exists in the hash table,
1458 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1459 vn_reference_t stored in the hashtable if something is found. */
1462 vn_reference_lookup_pieces (tree vuse, alias_set_type set, tree type,
1463 VEC (vn_reference_op_s, heap) *operands,
1464 vn_reference_t *vnresult, bool maywalk)
1466 struct vn_reference_s vr1;
1474 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1475 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1476 VEC_safe_grow (vn_reference_op_s, heap, shared_lookup_references,
1477 VEC_length (vn_reference_op_s, operands));
1478 memcpy (VEC_address (vn_reference_op_s, shared_lookup_references),
1479 VEC_address (vn_reference_op_s, operands),
1480 sizeof (vn_reference_op_s)
1481 * VEC_length (vn_reference_op_s, operands));
1482 vr1.operands = operands = shared_lookup_references
1483 = valueize_refs (shared_lookup_references);
1486 vr1.hashcode = vn_reference_compute_hash (&vr1);
1487 if ((cst = fully_constant_vn_reference_p (&vr1)))
1490 vn_reference_lookup_1 (&vr1, vnresult);
1496 if (ao_ref_init_from_vn_reference (&r, set, type, vr1.operands))
1498 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1499 vn_reference_lookup_2,
1500 vn_reference_lookup_3, &vr1);
1501 if (vr1.operands != operands)
1502 VEC_free (vn_reference_op_s, heap, vr1.operands);
1506 return (*vnresult)->result;
1511 /* Lookup OP in the current hash table, and return the resulting value
1512 number if it exists in the hash table. Return NULL_TREE if it does
1513 not exist in the hash table or if the result field of the structure
1514 was NULL.. VNRESULT will be filled in with the vn_reference_t
1515 stored in the hashtable if one exists. */
1518 vn_reference_lookup (tree op, tree vuse, bool maywalk,
1519 vn_reference_t *vnresult)
1521 VEC (vn_reference_op_s, heap) *operands;
1522 struct vn_reference_s vr1;
1528 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1529 vr1.operands = operands = valueize_shared_reference_ops_from_ref (op);
1530 vr1.type = TREE_TYPE (op);
1531 vr1.set = get_alias_set (op);
1532 vr1.hashcode = vn_reference_compute_hash (&vr1);
1533 if ((cst = fully_constant_vn_reference_p (&vr1)))
1539 vn_reference_t wvnresult;
1541 ao_ref_init (&r, op);
1543 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1544 vn_reference_lookup_2,
1545 vn_reference_lookup_3, &vr1);
1546 if (vr1.operands != operands)
1547 VEC_free (vn_reference_op_s, heap, vr1.operands);
1551 *vnresult = wvnresult;
1552 return wvnresult->result;
1558 return vn_reference_lookup_1 (&vr1, vnresult);
1562 /* Insert OP into the current hash table with a value number of
1563 RESULT, and return the resulting reference structure we created. */
1566 vn_reference_insert (tree op, tree result, tree vuse)
1571 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1572 if (TREE_CODE (result) == SSA_NAME)
1573 vr1->value_id = VN_INFO (result)->value_id;
1575 vr1->value_id = get_or_alloc_constant_value_id (result);
1576 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1577 vr1->operands = valueize_refs (create_reference_ops_from_ref (op));
1578 vr1->type = TREE_TYPE (op);
1579 vr1->set = get_alias_set (op);
1580 vr1->hashcode = vn_reference_compute_hash (vr1);
1581 vr1->result = TREE_CODE (result) == SSA_NAME ? SSA_VAL (result) : result;
1583 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1586 /* Because we lookup stores using vuses, and value number failures
1587 using the vdefs (see visit_reference_op_store for how and why),
1588 it's possible that on failure we may try to insert an already
1589 inserted store. This is not wrong, there is no ssa name for a
1590 store that we could use as a differentiator anyway. Thus, unlike
1591 the other lookup functions, you cannot gcc_assert (!*slot)
1594 /* But free the old slot in case of a collision. */
1596 free_reference (*slot);
1602 /* Insert a reference by it's pieces into the current hash table with
1603 a value number of RESULT. Return the resulting reference
1604 structure we created. */
1607 vn_reference_insert_pieces (tree vuse, alias_set_type set, tree type,
1608 VEC (vn_reference_op_s, heap) *operands,
1609 tree result, unsigned int value_id)
1615 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1616 vr1->value_id = value_id;
1617 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1618 vr1->operands = valueize_refs (operands);
1621 vr1->hashcode = vn_reference_compute_hash (vr1);
1622 if (result && TREE_CODE (result) == SSA_NAME)
1623 result = SSA_VAL (result);
1624 vr1->result = result;
1626 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1629 /* At this point we should have all the things inserted that we have
1630 seen before, and we should never try inserting something that
1632 gcc_assert (!*slot);
1634 free_reference (*slot);
1640 /* Compute and return the hash value for nary operation VBO1. */
1643 vn_nary_op_compute_hash (const vn_nary_op_t vno1)
1648 for (i = 0; i < vno1->length; ++i)
1649 if (TREE_CODE (vno1->op[i]) == SSA_NAME)
1650 vno1->op[i] = SSA_VAL (vno1->op[i]);
1652 if (vno1->length == 2
1653 && commutative_tree_code (vno1->opcode)
1654 && tree_swap_operands_p (vno1->op[0], vno1->op[1], false))
1656 tree temp = vno1->op[0];
1657 vno1->op[0] = vno1->op[1];
1661 hash = iterative_hash_hashval_t (vno1->opcode, 0);
1662 for (i = 0; i < vno1->length; ++i)
1663 hash = iterative_hash_expr (vno1->op[i], hash);
1668 /* Return the computed hashcode for nary operation P1. */
1671 vn_nary_op_hash (const void *p1)
1673 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1674 return vno1->hashcode;
1677 /* Compare nary operations P1 and P2 and return true if they are
1681 vn_nary_op_eq (const void *p1, const void *p2)
1683 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1684 const_vn_nary_op_t const vno2 = (const_vn_nary_op_t) p2;
1687 if (vno1->hashcode != vno2->hashcode)
1690 if (vno1->opcode != vno2->opcode
1691 || !types_compatible_p (vno1->type, vno2->type))
1694 for (i = 0; i < vno1->length; ++i)
1695 if (!expressions_equal_p (vno1->op[i], vno2->op[i]))
1701 /* Initialize VNO from the pieces provided. */
1704 init_vn_nary_op_from_pieces (vn_nary_op_t vno, unsigned int length,
1705 enum tree_code code, tree type, tree op0,
1706 tree op1, tree op2, tree op3)
1709 vno->length = length;
1717 /* Initialize VNO from OP. */
1720 init_vn_nary_op_from_op (vn_nary_op_t vno, tree op)
1724 vno->opcode = TREE_CODE (op);
1725 vno->length = TREE_CODE_LENGTH (TREE_CODE (op));
1726 vno->type = TREE_TYPE (op);
1727 for (i = 0; i < vno->length; ++i)
1728 vno->op[i] = TREE_OPERAND (op, i);
1731 /* Initialize VNO from STMT. */
1734 init_vn_nary_op_from_stmt (vn_nary_op_t vno, gimple stmt)
1738 vno->opcode = gimple_assign_rhs_code (stmt);
1739 vno->length = gimple_num_ops (stmt) - 1;
1740 vno->type = gimple_expr_type (stmt);
1741 for (i = 0; i < vno->length; ++i)
1742 vno->op[i] = gimple_op (stmt, i + 1);
1743 if (vno->opcode == REALPART_EXPR
1744 || vno->opcode == IMAGPART_EXPR
1745 || vno->opcode == VIEW_CONVERT_EXPR)
1746 vno->op[0] = TREE_OPERAND (vno->op[0], 0);
1749 /* Compute the hashcode for VNO and look for it in the hash table;
1750 return the resulting value number if it exists in the hash table.
1751 Return NULL_TREE if it does not exist in the hash table or if the
1752 result field of the operation is NULL. VNRESULT will contain the
1753 vn_nary_op_t from the hashtable if it exists. */
1756 vn_nary_op_lookup_1 (vn_nary_op_t vno, vn_nary_op_t *vnresult)
1763 vno->hashcode = vn_nary_op_compute_hash (vno);
1764 slot = htab_find_slot_with_hash (current_info->nary, vno, vno->hashcode,
1766 if (!slot && current_info == optimistic_info)
1767 slot = htab_find_slot_with_hash (valid_info->nary, vno, vno->hashcode,
1772 *vnresult = (vn_nary_op_t)*slot;
1773 return ((vn_nary_op_t)*slot)->result;
1776 /* Lookup a n-ary operation by its pieces and return the resulting value
1777 number if it exists in the hash table. Return NULL_TREE if it does
1778 not exist in the hash table or if the result field of the operation
1779 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1783 vn_nary_op_lookup_pieces (unsigned int length, enum tree_code code,
1784 tree type, tree op0, tree op1, tree op2,
1785 tree op3, vn_nary_op_t *vnresult)
1787 struct vn_nary_op_s vno1;
1788 init_vn_nary_op_from_pieces (&vno1, length, code, type, op0, op1, op2, op3);
1789 return vn_nary_op_lookup_1 (&vno1, vnresult);
1792 /* Lookup OP in the current hash table, and return the resulting value
1793 number if it exists in the hash table. Return NULL_TREE if it does
1794 not exist in the hash table or if the result field of the operation
1795 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1799 vn_nary_op_lookup (tree op, vn_nary_op_t *vnresult)
1801 struct vn_nary_op_s vno1;
1802 init_vn_nary_op_from_op (&vno1, op);
1803 return vn_nary_op_lookup_1 (&vno1, vnresult);
1806 /* Lookup the rhs of STMT in the current hash table, and return the resulting
1807 value number if it exists in the hash table. Return NULL_TREE if
1808 it does not exist in the hash table. VNRESULT will contain the
1809 vn_nary_op_t from the hashtable if it exists. */
1812 vn_nary_op_lookup_stmt (gimple stmt, vn_nary_op_t *vnresult)
1814 struct vn_nary_op_s vno1;
1815 init_vn_nary_op_from_stmt (&vno1, stmt);
1816 return vn_nary_op_lookup_1 (&vno1, vnresult);
1819 /* Return the size of a vn_nary_op_t with LENGTH operands. */
1822 sizeof_vn_nary_op (unsigned int length)
1824 return sizeof (struct vn_nary_op_s) - sizeof (tree) * (4 - length);
1827 /* Allocate a vn_nary_op_t with LENGTH operands on STACK. */
1830 alloc_vn_nary_op_noinit (unsigned int length, struct obstack *stack)
1832 return (vn_nary_op_t) obstack_alloc (stack, sizeof_vn_nary_op (length));
1835 /* Allocate and initialize a vn_nary_op_t on CURRENT_INFO's
1839 alloc_vn_nary_op (unsigned int length, tree result, unsigned int value_id)
1841 vn_nary_op_t vno1 = alloc_vn_nary_op_noinit (length,
1842 ¤t_info->nary_obstack);
1844 vno1->value_id = value_id;
1845 vno1->length = length;
1846 vno1->result = result;
1851 /* Insert VNO into TABLE. If COMPUTE_HASH is true, then compute
1852 VNO->HASHCODE first. */
1855 vn_nary_op_insert_into (vn_nary_op_t vno, htab_t table, bool compute_hash)
1860 vno->hashcode = vn_nary_op_compute_hash (vno);
1862 slot = htab_find_slot_with_hash (table, vno, vno->hashcode, INSERT);
1863 gcc_assert (!*slot);
1869 /* Insert a n-ary operation into the current hash table using it's
1870 pieces. Return the vn_nary_op_t structure we created and put in
1874 vn_nary_op_insert_pieces (unsigned int length, enum tree_code code,
1875 tree type, tree op0,
1876 tree op1, tree op2, tree op3,
1878 unsigned int value_id)
1882 vno1 = alloc_vn_nary_op (length, result, value_id);
1883 init_vn_nary_op_from_pieces (vno1, length, code, type, op0, op1, op2, op3);
1884 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1887 /* Insert OP into the current hash table with a value number of
1888 RESULT. Return the vn_nary_op_t structure we created and put in
1892 vn_nary_op_insert (tree op, tree result)
1894 unsigned length = TREE_CODE_LENGTH (TREE_CODE (op));
1897 vno1 = alloc_vn_nary_op (length, result, VN_INFO (result)->value_id);
1898 init_vn_nary_op_from_op (vno1, op);
1899 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1902 /* Insert the rhs of STMT into the current hash table with a value number of
1906 vn_nary_op_insert_stmt (gimple stmt, tree result)
1908 unsigned length = gimple_num_ops (stmt) - 1;
1911 vno1 = alloc_vn_nary_op (length, result, VN_INFO (result)->value_id);
1912 init_vn_nary_op_from_stmt (vno1, stmt);
1913 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1916 /* Compute a hashcode for PHI operation VP1 and return it. */
1918 static inline hashval_t
1919 vn_phi_compute_hash (vn_phi_t vp1)
1926 result = vp1->block->index;
1928 /* If all PHI arguments are constants we need to distinguish
1929 the PHI node via its type. */
1930 type = TREE_TYPE (VEC_index (tree, vp1->phiargs, 0));
1931 result += (INTEGRAL_TYPE_P (type)
1932 + (INTEGRAL_TYPE_P (type)
1933 ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
1935 FOR_EACH_VEC_ELT (tree, vp1->phiargs, i, phi1op)
1937 if (phi1op == VN_TOP)
1939 result = iterative_hash_expr (phi1op, result);
1945 /* Return the computed hashcode for phi operation P1. */
1948 vn_phi_hash (const void *p1)
1950 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1951 return vp1->hashcode;
1954 /* Compare two phi entries for equality, ignoring VN_TOP arguments. */
1957 vn_phi_eq (const void *p1, const void *p2)
1959 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1960 const_vn_phi_t const vp2 = (const_vn_phi_t) p2;
1962 if (vp1->hashcode != vp2->hashcode)
1965 if (vp1->block == vp2->block)
1970 /* If the PHI nodes do not have compatible types
1971 they are not the same. */
1972 if (!types_compatible_p (TREE_TYPE (VEC_index (tree, vp1->phiargs, 0)),
1973 TREE_TYPE (VEC_index (tree, vp2->phiargs, 0))))
1976 /* Any phi in the same block will have it's arguments in the
1977 same edge order, because of how we store phi nodes. */
1978 FOR_EACH_VEC_ELT (tree, vp1->phiargs, i, phi1op)
1980 tree phi2op = VEC_index (tree, vp2->phiargs, i);
1981 if (phi1op == VN_TOP || phi2op == VN_TOP)
1983 if (!expressions_equal_p (phi1op, phi2op))
1991 static VEC(tree, heap) *shared_lookup_phiargs;
1993 /* Lookup PHI in the current hash table, and return the resulting
1994 value number if it exists in the hash table. Return NULL_TREE if
1995 it does not exist in the hash table. */
1998 vn_phi_lookup (gimple phi)
2001 struct vn_phi_s vp1;
2004 VEC_truncate (tree, shared_lookup_phiargs, 0);
2006 /* Canonicalize the SSA_NAME's to their value number. */
2007 for (i = 0; i < gimple_phi_num_args (phi); i++)
2009 tree def = PHI_ARG_DEF (phi, i);
2010 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
2011 VEC_safe_push (tree, heap, shared_lookup_phiargs, def);
2013 vp1.phiargs = shared_lookup_phiargs;
2014 vp1.block = gimple_bb (phi);
2015 vp1.hashcode = vn_phi_compute_hash (&vp1);
2016 slot = htab_find_slot_with_hash (current_info->phis, &vp1, vp1.hashcode,
2018 if (!slot && current_info == optimistic_info)
2019 slot = htab_find_slot_with_hash (valid_info->phis, &vp1, vp1.hashcode,
2023 return ((vn_phi_t)*slot)->result;
2026 /* Insert PHI into the current hash table with a value number of
2030 vn_phi_insert (gimple phi, tree result)
2033 vn_phi_t vp1 = (vn_phi_t) pool_alloc (current_info->phis_pool);
2035 VEC (tree, heap) *args = NULL;
2037 /* Canonicalize the SSA_NAME's to their value number. */
2038 for (i = 0; i < gimple_phi_num_args (phi); i++)
2040 tree def = PHI_ARG_DEF (phi, i);
2041 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
2042 VEC_safe_push (tree, heap, args, def);
2044 vp1->value_id = VN_INFO (result)->value_id;
2045 vp1->phiargs = args;
2046 vp1->block = gimple_bb (phi);
2047 vp1->result = result;
2048 vp1->hashcode = vn_phi_compute_hash (vp1);
2050 slot = htab_find_slot_with_hash (current_info->phis, vp1, vp1->hashcode,
2053 /* Because we iterate over phi operations more than once, it's
2054 possible the slot might already exist here, hence no assert.*/
2060 /* Print set of components in strongly connected component SCC to OUT. */
2063 print_scc (FILE *out, VEC (tree, heap) *scc)
2068 fprintf (out, "SCC consists of: ");
2069 FOR_EACH_VEC_ELT (tree, scc, i, var)
2071 print_generic_expr (out, var, 0);
2074 fprintf (out, "\n");
2077 /* Set the value number of FROM to TO, return true if it has changed
2081 set_ssa_val_to (tree from, tree to)
2086 && TREE_CODE (to) == SSA_NAME
2087 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to))
2090 /* The only thing we allow as value numbers are VN_TOP, ssa_names
2091 and invariants. So assert that here. */
2092 gcc_assert (to != NULL_TREE
2094 || TREE_CODE (to) == SSA_NAME
2095 || is_gimple_min_invariant (to)));
2097 if (dump_file && (dump_flags & TDF_DETAILS))
2099 fprintf (dump_file, "Setting value number of ");
2100 print_generic_expr (dump_file, from, 0);
2101 fprintf (dump_file, " to ");
2102 print_generic_expr (dump_file, to, 0);
2105 currval = SSA_VAL (from);
2107 if (currval != to && !operand_equal_p (currval, to, OEP_PURE_SAME))
2109 VN_INFO (from)->valnum = to;
2110 if (dump_file && (dump_flags & TDF_DETAILS))
2111 fprintf (dump_file, " (changed)\n");
2114 if (dump_file && (dump_flags & TDF_DETAILS))
2115 fprintf (dump_file, "\n");
2119 /* Set all definitions in STMT to value number to themselves.
2120 Return true if a value number changed. */
2123 defs_to_varying (gimple stmt)
2125 bool changed = false;
2129 FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_ALL_DEFS)
2131 tree def = DEF_FROM_PTR (defp);
2133 VN_INFO (def)->use_processed = true;
2134 changed |= set_ssa_val_to (def, def);
2139 static bool expr_has_constants (tree expr);
2140 static tree valueize_expr (tree expr);
2142 /* Visit a copy between LHS and RHS, return true if the value number
2146 visit_copy (tree lhs, tree rhs)
2148 /* Follow chains of copies to their destination. */
2149 while (TREE_CODE (rhs) == SSA_NAME
2150 && SSA_VAL (rhs) != rhs)
2151 rhs = SSA_VAL (rhs);
2153 /* The copy may have a more interesting constant filled expression
2154 (we don't, since we know our RHS is just an SSA name). */
2155 if (TREE_CODE (rhs) == SSA_NAME)
2157 VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants;
2158 VN_INFO (lhs)->expr = VN_INFO (rhs)->expr;
2161 return set_ssa_val_to (lhs, rhs);
2164 /* Visit a unary operator RHS, value number it, and return true if the
2165 value number of LHS has changed as a result. */
2168 visit_unary_op (tree lhs, gimple stmt)
2170 bool changed = false;
2171 tree result = vn_nary_op_lookup_stmt (stmt, NULL);
2175 changed = set_ssa_val_to (lhs, result);
2179 changed = set_ssa_val_to (lhs, lhs);
2180 vn_nary_op_insert_stmt (stmt, lhs);
2186 /* Visit a binary operator RHS, value number it, and return true if the
2187 value number of LHS has changed as a result. */
2190 visit_binary_op (tree lhs, gimple stmt)
2192 bool changed = false;
2193 tree result = vn_nary_op_lookup_stmt (stmt, NULL);
2197 changed = set_ssa_val_to (lhs, result);
2201 changed = set_ssa_val_to (lhs, lhs);
2202 vn_nary_op_insert_stmt (stmt, lhs);
2208 /* Visit a call STMT storing into LHS. Return true if the value number
2209 of the LHS has changed as a result. */
2212 visit_reference_op_call (tree lhs, gimple stmt)
2214 bool changed = false;
2215 struct vn_reference_s vr1;
2217 tree vuse = gimple_vuse (stmt);
2219 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
2220 vr1.operands = valueize_shared_reference_ops_from_call (stmt);
2221 vr1.type = gimple_expr_type (stmt);
2223 vr1.hashcode = vn_reference_compute_hash (&vr1);
2224 result = vn_reference_lookup_1 (&vr1, NULL);
2227 changed = set_ssa_val_to (lhs, result);
2228 if (TREE_CODE (result) == SSA_NAME
2229 && VN_INFO (result)->has_constants)
2230 VN_INFO (lhs)->has_constants = true;
2236 changed = set_ssa_val_to (lhs, lhs);
2237 vr2 = (vn_reference_t) pool_alloc (current_info->references_pool);
2238 vr2->vuse = vr1.vuse;
2239 vr2->operands = valueize_refs (create_reference_ops_from_call (stmt));
2240 vr2->type = vr1.type;
2242 vr2->hashcode = vr1.hashcode;
2244 slot = htab_find_slot_with_hash (current_info->references,
2245 vr2, vr2->hashcode, INSERT);
2247 free_reference (*slot);
2254 /* Visit a load from a reference operator RHS, part of STMT, value number it,
2255 and return true if the value number of the LHS has changed as a result. */
2258 visit_reference_op_load (tree lhs, tree op, gimple stmt)
2260 bool changed = false;
2264 last_vuse = gimple_vuse (stmt);
2265 last_vuse_ptr = &last_vuse;
2266 result = vn_reference_lookup (op, gimple_vuse (stmt), true, NULL);
2267 last_vuse_ptr = NULL;
2269 /* If we have a VCE, try looking up its operand as it might be stored in
2270 a different type. */
2271 if (!result && TREE_CODE (op) == VIEW_CONVERT_EXPR)
2272 result = vn_reference_lookup (TREE_OPERAND (op, 0), gimple_vuse (stmt),
2275 /* We handle type-punning through unions by value-numbering based
2276 on offset and size of the access. Be prepared to handle a
2277 type-mismatch here via creating a VIEW_CONVERT_EXPR. */
2279 && !useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (op)))
2281 /* We will be setting the value number of lhs to the value number
2282 of VIEW_CONVERT_EXPR <TREE_TYPE (result)> (result).
2283 So first simplify and lookup this expression to see if it
2284 is already available. */
2285 tree val = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (op), result);
2286 if ((CONVERT_EXPR_P (val)
2287 || TREE_CODE (val) == VIEW_CONVERT_EXPR)
2288 && TREE_CODE (TREE_OPERAND (val, 0)) == SSA_NAME)
2290 tree tem = valueize_expr (vn_get_expr_for (TREE_OPERAND (val, 0)));
2291 if ((CONVERT_EXPR_P (tem)
2292 || TREE_CODE (tem) == VIEW_CONVERT_EXPR)
2293 && (tem = fold_unary_ignore_overflow (TREE_CODE (val),
2294 TREE_TYPE (val), tem)))
2298 if (!is_gimple_min_invariant (val)
2299 && TREE_CODE (val) != SSA_NAME)
2300 result = vn_nary_op_lookup (val, NULL);
2301 /* If the expression is not yet available, value-number lhs to
2302 a new SSA_NAME we create. */
2305 result = make_ssa_name (SSA_NAME_VAR (lhs), gimple_build_nop ());
2306 /* Initialize value-number information properly. */
2307 VN_INFO_GET (result)->valnum = result;
2308 VN_INFO (result)->value_id = get_next_value_id ();
2309 VN_INFO (result)->expr = val;
2310 VN_INFO (result)->has_constants = expr_has_constants (val);
2311 VN_INFO (result)->needs_insertion = true;
2312 /* As all "inserted" statements are singleton SCCs, insert
2313 to the valid table. This is strictly needed to
2314 avoid re-generating new value SSA_NAMEs for the same
2315 expression during SCC iteration over and over (the
2316 optimistic table gets cleared after each iteration).
2317 We do not need to insert into the optimistic table, as
2318 lookups there will fall back to the valid table. */
2319 if (current_info == optimistic_info)
2321 current_info = valid_info;
2322 vn_nary_op_insert (val, result);
2323 current_info = optimistic_info;
2326 vn_nary_op_insert (val, result);
2327 if (dump_file && (dump_flags & TDF_DETAILS))
2329 fprintf (dump_file, "Inserting name ");
2330 print_generic_expr (dump_file, result, 0);
2331 fprintf (dump_file, " for expression ");
2332 print_generic_expr (dump_file, val, 0);
2333 fprintf (dump_file, "\n");
2340 changed = set_ssa_val_to (lhs, result);
2341 if (TREE_CODE (result) == SSA_NAME
2342 && VN_INFO (result)->has_constants)
2344 VN_INFO (lhs)->expr = VN_INFO (result)->expr;
2345 VN_INFO (lhs)->has_constants = true;
2350 changed = set_ssa_val_to (lhs, lhs);
2351 vn_reference_insert (op, lhs, last_vuse);
2358 /* Visit a store to a reference operator LHS, part of STMT, value number it,
2359 and return true if the value number of the LHS has changed as a result. */
2362 visit_reference_op_store (tree lhs, tree op, gimple stmt)
2364 bool changed = false;
2366 bool resultsame = false;
2368 /* First we want to lookup using the *vuses* from the store and see
2369 if there the last store to this location with the same address
2372 The vuses represent the memory state before the store. If the
2373 memory state, address, and value of the store is the same as the
2374 last store to this location, then this store will produce the
2375 same memory state as that store.
2377 In this case the vdef versions for this store are value numbered to those
2378 vuse versions, since they represent the same memory state after
2381 Otherwise, the vdefs for the store are used when inserting into
2382 the table, since the store generates a new memory state. */
2384 result = vn_reference_lookup (lhs, gimple_vuse (stmt), false, NULL);
2388 if (TREE_CODE (result) == SSA_NAME)
2389 result = SSA_VAL (result);
2390 if (TREE_CODE (op) == SSA_NAME)
2392 resultsame = expressions_equal_p (result, op);
2395 if (!result || !resultsame)
2399 if (dump_file && (dump_flags & TDF_DETAILS))
2401 fprintf (dump_file, "No store match\n");
2402 fprintf (dump_file, "Value numbering store ");
2403 print_generic_expr (dump_file, lhs, 0);
2404 fprintf (dump_file, " to ");
2405 print_generic_expr (dump_file, op, 0);
2406 fprintf (dump_file, "\n");
2408 /* Have to set value numbers before insert, since insert is
2409 going to valueize the references in-place. */
2410 if ((vdef = gimple_vdef (stmt)))
2412 VN_INFO (vdef)->use_processed = true;
2413 changed |= set_ssa_val_to (vdef, vdef);
2416 /* Do not insert structure copies into the tables. */
2417 if (is_gimple_min_invariant (op)
2418 || is_gimple_reg (op))
2419 vn_reference_insert (lhs, op, vdef);
2423 /* We had a match, so value number the vdef to have the value
2424 number of the vuse it came from. */
2427 if (dump_file && (dump_flags & TDF_DETAILS))
2428 fprintf (dump_file, "Store matched earlier value,"
2429 "value numbering store vdefs to matching vuses.\n");
2431 def = gimple_vdef (stmt);
2432 use = gimple_vuse (stmt);
2434 VN_INFO (def)->use_processed = true;
2435 changed |= set_ssa_val_to (def, SSA_VAL (use));
2441 /* Visit and value number PHI, return true if the value number
2445 visit_phi (gimple phi)
2447 bool changed = false;
2449 tree sameval = VN_TOP;
2450 bool allsame = true;
2453 /* TODO: We could check for this in init_sccvn, and replace this
2454 with a gcc_assert. */
2455 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
2456 return set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2458 /* See if all non-TOP arguments have the same value. TOP is
2459 equivalent to everything, so we can ignore it. */
2460 for (i = 0; i < gimple_phi_num_args (phi); i++)
2462 tree def = PHI_ARG_DEF (phi, i);
2464 if (TREE_CODE (def) == SSA_NAME)
2465 def = SSA_VAL (def);
2468 if (sameval == VN_TOP)
2474 if (!expressions_equal_p (def, sameval))
2482 /* If all value numbered to the same value, the phi node has that
2486 if (is_gimple_min_invariant (sameval))
2488 VN_INFO (PHI_RESULT (phi))->has_constants = true;
2489 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2493 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2494 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2497 if (TREE_CODE (sameval) == SSA_NAME)
2498 return visit_copy (PHI_RESULT (phi), sameval);
2500 return set_ssa_val_to (PHI_RESULT (phi), sameval);
2503 /* Otherwise, see if it is equivalent to a phi node in this block. */
2504 result = vn_phi_lookup (phi);
2507 if (TREE_CODE (result) == SSA_NAME)
2508 changed = visit_copy (PHI_RESULT (phi), result);
2510 changed = set_ssa_val_to (PHI_RESULT (phi), result);
2514 vn_phi_insert (phi, PHI_RESULT (phi));
2515 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2516 VN_INFO (PHI_RESULT (phi))->expr = PHI_RESULT (phi);
2517 changed = set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2523 /* Return true if EXPR contains constants. */
2526 expr_has_constants (tree expr)
2528 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2531 return is_gimple_min_invariant (TREE_OPERAND (expr, 0));
2534 return is_gimple_min_invariant (TREE_OPERAND (expr, 0))
2535 || is_gimple_min_invariant (TREE_OPERAND (expr, 1));
2536 /* Constants inside reference ops are rarely interesting, but
2537 it can take a lot of looking to find them. */
2539 case tcc_declaration:
2542 return is_gimple_min_invariant (expr);
2547 /* Return true if STMT contains constants. */
2550 stmt_has_constants (gimple stmt)
2552 if (gimple_code (stmt) != GIMPLE_ASSIGN)
2555 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2557 case GIMPLE_UNARY_RHS:
2558 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2560 case GIMPLE_BINARY_RHS:
2561 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2562 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt)));
2563 case GIMPLE_TERNARY_RHS:
2564 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2565 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))
2566 || is_gimple_min_invariant (gimple_assign_rhs3 (stmt)));
2567 case GIMPLE_SINGLE_RHS:
2568 /* Constants inside reference ops are rarely interesting, but
2569 it can take a lot of looking to find them. */
2570 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2577 /* Replace SSA_NAMES in expr with their value numbers, and return the
2579 This is performed in place. */
2582 valueize_expr (tree expr)
2584 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2587 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2588 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2589 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2592 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2593 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2594 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2595 if (TREE_CODE (TREE_OPERAND (expr, 1)) == SSA_NAME
2596 && SSA_VAL (TREE_OPERAND (expr, 1)) != VN_TOP)
2597 TREE_OPERAND (expr, 1) = SSA_VAL (TREE_OPERAND (expr, 1));
2605 /* Simplify the binary expression RHS, and return the result if
2609 simplify_binary_expression (gimple stmt)
2611 tree result = NULL_TREE;
2612 tree op0 = gimple_assign_rhs1 (stmt);
2613 tree op1 = gimple_assign_rhs2 (stmt);
2615 /* This will not catch every single case we could combine, but will
2616 catch those with constants. The goal here is to simultaneously
2617 combine constants between expressions, but avoid infinite
2618 expansion of expressions during simplification. */
2619 if (TREE_CODE (op0) == SSA_NAME)
2621 if (VN_INFO (op0)->has_constants
2622 || TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
2623 op0 = valueize_expr (vn_get_expr_for (op0));
2624 else if (SSA_VAL (op0) != VN_TOP && SSA_VAL (op0) != op0)
2625 op0 = SSA_VAL (op0);
2628 if (TREE_CODE (op1) == SSA_NAME)
2630 if (VN_INFO (op1)->has_constants)
2631 op1 = valueize_expr (vn_get_expr_for (op1));
2632 else if (SSA_VAL (op1) != VN_TOP && SSA_VAL (op1) != op1)
2633 op1 = SSA_VAL (op1);
2636 /* Avoid folding if nothing changed. */
2637 if (op0 == gimple_assign_rhs1 (stmt)
2638 && op1 == gimple_assign_rhs2 (stmt))
2641 fold_defer_overflow_warnings ();
2643 result = fold_binary (gimple_assign_rhs_code (stmt),
2644 gimple_expr_type (stmt), op0, op1);
2646 STRIP_USELESS_TYPE_CONVERSION (result);
2648 fold_undefer_overflow_warnings (result && valid_gimple_rhs_p (result),
2651 /* Make sure result is not a complex expression consisting
2652 of operators of operators (IE (a + b) + (a + c))
2653 Otherwise, we will end up with unbounded expressions if
2654 fold does anything at all. */
2655 if (result && valid_gimple_rhs_p (result))
2661 /* Simplify the unary expression RHS, and return the result if
2665 simplify_unary_expression (gimple stmt)
2667 tree result = NULL_TREE;
2668 tree orig_op0, op0 = gimple_assign_rhs1 (stmt);
2670 /* We handle some tcc_reference codes here that are all
2671 GIMPLE_ASSIGN_SINGLE codes. */
2672 if (gimple_assign_rhs_code (stmt) == REALPART_EXPR
2673 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2674 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2675 op0 = TREE_OPERAND (op0, 0);
2677 if (TREE_CODE (op0) != SSA_NAME)
2681 if (VN_INFO (op0)->has_constants)
2682 op0 = valueize_expr (vn_get_expr_for (op0));
2683 else if (gimple_assign_cast_p (stmt)
2684 || gimple_assign_rhs_code (stmt) == REALPART_EXPR
2685 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2686 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2688 /* We want to do tree-combining on conversion-like expressions.
2689 Make sure we feed only SSA_NAMEs or constants to fold though. */
2690 tree tem = valueize_expr (vn_get_expr_for (op0));
2691 if (UNARY_CLASS_P (tem)
2692 || BINARY_CLASS_P (tem)
2693 || TREE_CODE (tem) == VIEW_CONVERT_EXPR
2694 || TREE_CODE (tem) == SSA_NAME
2695 || is_gimple_min_invariant (tem))
2699 /* Avoid folding if nothing changed, but remember the expression. */
2700 if (op0 == orig_op0)
2703 result = fold_unary_ignore_overflow (gimple_assign_rhs_code (stmt),
2704 gimple_expr_type (stmt), op0);
2707 STRIP_USELESS_TYPE_CONVERSION (result);
2708 if (valid_gimple_rhs_p (result))
2715 /* Try to simplify RHS using equivalences and constant folding. */
2718 try_to_simplify (gimple stmt)
2722 /* For stores we can end up simplifying a SSA_NAME rhs. Just return
2723 in this case, there is no point in doing extra work. */
2724 if (gimple_assign_copy_p (stmt)
2725 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
2728 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2730 case tcc_declaration:
2731 tem = get_symbol_constant_value (gimple_assign_rhs1 (stmt));
2737 /* Do not do full-blown reference lookup here, but simplify
2738 reads from constant aggregates. */
2739 tem = fold_const_aggregate_ref (gimple_assign_rhs1 (stmt));
2743 /* Fallthrough for some codes that can operate on registers. */
2744 if (!(TREE_CODE (gimple_assign_rhs1 (stmt)) == REALPART_EXPR
2745 || TREE_CODE (gimple_assign_rhs1 (stmt)) == IMAGPART_EXPR
2746 || TREE_CODE (gimple_assign_rhs1 (stmt)) == VIEW_CONVERT_EXPR))
2748 /* We could do a little more with unary ops, if they expand
2749 into binary ops, but it's debatable whether it is worth it. */
2751 return simplify_unary_expression (stmt);
2753 case tcc_comparison:
2755 return simplify_binary_expression (stmt);
2764 /* Visit and value number USE, return true if the value number
2768 visit_use (tree use)
2770 bool changed = false;
2771 gimple stmt = SSA_NAME_DEF_STMT (use);
2773 VN_INFO (use)->use_processed = true;
2775 gcc_assert (!SSA_NAME_IN_FREE_LIST (use));
2776 if (dump_file && (dump_flags & TDF_DETAILS)
2777 && !SSA_NAME_IS_DEFAULT_DEF (use))
2779 fprintf (dump_file, "Value numbering ");
2780 print_generic_expr (dump_file, use, 0);
2781 fprintf (dump_file, " stmt = ");
2782 print_gimple_stmt (dump_file, stmt, 0, 0);
2785 /* Handle uninitialized uses. */
2786 if (SSA_NAME_IS_DEFAULT_DEF (use))
2787 changed = set_ssa_val_to (use, use);
2790 if (gimple_code (stmt) == GIMPLE_PHI)
2791 changed = visit_phi (stmt);
2792 else if (!gimple_has_lhs (stmt)
2793 || gimple_has_volatile_ops (stmt)
2794 || stmt_could_throw_p (stmt))
2795 changed = defs_to_varying (stmt);
2796 else if (is_gimple_assign (stmt))
2798 tree lhs = gimple_assign_lhs (stmt);
2801 /* Shortcut for copies. Simplifying copies is pointless,
2802 since we copy the expression and value they represent. */
2803 if (gimple_assign_copy_p (stmt)
2804 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2805 && TREE_CODE (lhs) == SSA_NAME)
2807 changed = visit_copy (lhs, gimple_assign_rhs1 (stmt));
2810 simplified = try_to_simplify (stmt);
2813 if (dump_file && (dump_flags & TDF_DETAILS))
2815 fprintf (dump_file, "RHS ");
2816 print_gimple_expr (dump_file, stmt, 0, 0);
2817 fprintf (dump_file, " simplified to ");
2818 print_generic_expr (dump_file, simplified, 0);
2819 if (TREE_CODE (lhs) == SSA_NAME)
2820 fprintf (dump_file, " has constants %d\n",
2821 expr_has_constants (simplified));
2823 fprintf (dump_file, "\n");
2826 /* Setting value numbers to constants will occasionally
2827 screw up phi congruence because constants are not
2828 uniquely associated with a single ssa name that can be
2831 && is_gimple_min_invariant (simplified)
2832 && TREE_CODE (lhs) == SSA_NAME)
2834 VN_INFO (lhs)->expr = simplified;
2835 VN_INFO (lhs)->has_constants = true;
2836 changed = set_ssa_val_to (lhs, simplified);
2840 && TREE_CODE (simplified) == SSA_NAME
2841 && TREE_CODE (lhs) == SSA_NAME)
2843 changed = visit_copy (lhs, simplified);
2846 else if (simplified)
2848 if (TREE_CODE (lhs) == SSA_NAME)
2850 VN_INFO (lhs)->has_constants = expr_has_constants (simplified);
2851 /* We have to unshare the expression or else
2852 valuizing may change the IL stream. */
2853 VN_INFO (lhs)->expr = unshare_expr (simplified);
2856 else if (stmt_has_constants (stmt)
2857 && TREE_CODE (lhs) == SSA_NAME)
2858 VN_INFO (lhs)->has_constants = true;
2859 else if (TREE_CODE (lhs) == SSA_NAME)
2861 /* We reset expr and constantness here because we may
2862 have been value numbering optimistically, and
2863 iterating. They may become non-constant in this case,
2864 even if they were optimistically constant. */
2866 VN_INFO (lhs)->has_constants = false;
2867 VN_INFO (lhs)->expr = NULL_TREE;
2870 if ((TREE_CODE (lhs) == SSA_NAME
2871 /* We can substitute SSA_NAMEs that are live over
2872 abnormal edges with their constant value. */
2873 && !(gimple_assign_copy_p (stmt)
2874 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2876 && is_gimple_min_invariant (simplified))
2877 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2878 /* Stores or copies from SSA_NAMEs that are live over
2879 abnormal edges are a problem. */
2880 || (gimple_assign_single_p (stmt)
2881 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2882 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt))))
2883 changed = defs_to_varying (stmt);
2884 else if (REFERENCE_CLASS_P (lhs) || DECL_P (lhs))
2886 changed = visit_reference_op_store (lhs, gimple_assign_rhs1 (stmt), stmt);
2888 else if (TREE_CODE (lhs) == SSA_NAME)
2890 if ((gimple_assign_copy_p (stmt)
2891 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2893 && is_gimple_min_invariant (simplified)))
2895 VN_INFO (lhs)->has_constants = true;
2897 changed = set_ssa_val_to (lhs, simplified);
2899 changed = set_ssa_val_to (lhs, gimple_assign_rhs1 (stmt));
2903 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2905 case GIMPLE_UNARY_RHS:
2906 changed = visit_unary_op (lhs, stmt);
2908 case GIMPLE_BINARY_RHS:
2909 changed = visit_binary_op (lhs, stmt);
2911 case GIMPLE_SINGLE_RHS:
2912 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2915 /* VOP-less references can go through unary case. */
2916 if ((gimple_assign_rhs_code (stmt) == REALPART_EXPR
2917 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2918 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR )
2919 && TREE_CODE (TREE_OPERAND (gimple_assign_rhs1 (stmt), 0)) == SSA_NAME)
2921 changed = visit_unary_op (lhs, stmt);
2925 case tcc_declaration:
2926 changed = visit_reference_op_load
2927 (lhs, gimple_assign_rhs1 (stmt), stmt);
2929 case tcc_expression:
2930 if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
2932 changed = visit_unary_op (lhs, stmt);
2937 changed = defs_to_varying (stmt);
2941 changed = defs_to_varying (stmt);
2947 changed = defs_to_varying (stmt);
2949 else if (is_gimple_call (stmt))
2951 tree lhs = gimple_call_lhs (stmt);
2953 /* ??? We could try to simplify calls. */
2955 if (stmt_has_constants (stmt)
2956 && TREE_CODE (lhs) == SSA_NAME)
2957 VN_INFO (lhs)->has_constants = true;
2958 else if (TREE_CODE (lhs) == SSA_NAME)
2960 /* We reset expr and constantness here because we may
2961 have been value numbering optimistically, and
2962 iterating. They may become non-constant in this case,
2963 even if they were optimistically constant. */
2964 VN_INFO (lhs)->has_constants = false;
2965 VN_INFO (lhs)->expr = NULL_TREE;
2968 if (TREE_CODE (lhs) == SSA_NAME
2969 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2970 changed = defs_to_varying (stmt);
2971 /* ??? We should handle stores from calls. */
2972 else if (TREE_CODE (lhs) == SSA_NAME)
2974 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2975 changed = visit_reference_op_call (lhs, stmt);
2977 changed = defs_to_varying (stmt);
2980 changed = defs_to_varying (stmt);
2987 /* Compare two operands by reverse postorder index */
2990 compare_ops (const void *pa, const void *pb)
2992 const tree opa = *((const tree *)pa);
2993 const tree opb = *((const tree *)pb);
2994 gimple opstmta = SSA_NAME_DEF_STMT (opa);
2995 gimple opstmtb = SSA_NAME_DEF_STMT (opb);
2999 if (gimple_nop_p (opstmta) && gimple_nop_p (opstmtb))
3000 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3001 else if (gimple_nop_p (opstmta))
3003 else if (gimple_nop_p (opstmtb))
3006 bba = gimple_bb (opstmta);
3007 bbb = gimple_bb (opstmtb);
3010 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3018 if (gimple_code (opstmta) == GIMPLE_PHI
3019 && gimple_code (opstmtb) == GIMPLE_PHI)
3020 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3021 else if (gimple_code (opstmta) == GIMPLE_PHI)
3023 else if (gimple_code (opstmtb) == GIMPLE_PHI)
3025 else if (gimple_uid (opstmta) != gimple_uid (opstmtb))
3026 return gimple_uid (opstmta) - gimple_uid (opstmtb);
3028 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3030 return rpo_numbers[bba->index] - rpo_numbers[bbb->index];
3033 /* Sort an array containing members of a strongly connected component
3034 SCC so that the members are ordered by RPO number.
3035 This means that when the sort is complete, iterating through the
3036 array will give you the members in RPO order. */
3039 sort_scc (VEC (tree, heap) *scc)
3041 qsort (VEC_address (tree, scc),
3042 VEC_length (tree, scc),
3047 /* Insert the no longer used nary ONARY to the hash INFO. */
3050 copy_nary (vn_nary_op_t onary, vn_tables_t info)
3052 size_t size = sizeof_vn_nary_op (onary->length);
3053 vn_nary_op_t nary = alloc_vn_nary_op_noinit (onary->length,
3054 &info->nary_obstack);
3055 memcpy (nary, onary, size);
3056 vn_nary_op_insert_into (nary, info->nary, false);
3059 /* Insert the no longer used phi OPHI to the hash INFO. */
3062 copy_phi (vn_phi_t ophi, vn_tables_t info)
3064 vn_phi_t phi = (vn_phi_t) pool_alloc (info->phis_pool);
3066 memcpy (phi, ophi, sizeof (*phi));
3067 ophi->phiargs = NULL;
3068 slot = htab_find_slot_with_hash (info->phis, phi, phi->hashcode, INSERT);
3069 gcc_assert (!*slot);
3073 /* Insert the no longer used reference OREF to the hash INFO. */
3076 copy_reference (vn_reference_t oref, vn_tables_t info)
3080 ref = (vn_reference_t) pool_alloc (info->references_pool);
3081 memcpy (ref, oref, sizeof (*ref));
3082 oref->operands = NULL;
3083 slot = htab_find_slot_with_hash (info->references, ref, ref->hashcode,
3086 free_reference (*slot);
3090 /* Process a strongly connected component in the SSA graph. */
3093 process_scc (VEC (tree, heap) *scc)
3097 unsigned int iterations = 0;
3098 bool changed = true;
3104 /* If the SCC has a single member, just visit it. */
3105 if (VEC_length (tree, scc) == 1)
3107 tree use = VEC_index (tree, scc, 0);
3108 if (!VN_INFO (use)->use_processed)
3113 /* Iterate over the SCC with the optimistic table until it stops
3115 current_info = optimistic_info;
3120 /* As we are value-numbering optimistically we have to
3121 clear the expression tables and the simplified expressions
3122 in each iteration until we converge. */
3123 htab_empty (optimistic_info->nary);
3124 htab_empty (optimistic_info->phis);
3125 htab_empty (optimistic_info->references);
3126 obstack_free (&optimistic_info->nary_obstack, NULL);
3127 gcc_obstack_init (&optimistic_info->nary_obstack);
3128 empty_alloc_pool (optimistic_info->phis_pool);
3129 empty_alloc_pool (optimistic_info->references_pool);
3130 FOR_EACH_VEC_ELT (tree, scc, i, var)
3131 VN_INFO (var)->expr = NULL_TREE;
3132 FOR_EACH_VEC_ELT (tree, scc, i, var)
3133 changed |= visit_use (var);
3136 statistics_histogram_event (cfun, "SCC iterations", iterations);
3138 /* Finally, copy the contents of the no longer used optimistic
3139 table to the valid table. */
3140 FOR_EACH_HTAB_ELEMENT (optimistic_info->nary, nary, vn_nary_op_t, hi)
3141 copy_nary (nary, valid_info);
3142 FOR_EACH_HTAB_ELEMENT (optimistic_info->phis, phi, vn_phi_t, hi)
3143 copy_phi (phi, valid_info);
3144 FOR_EACH_HTAB_ELEMENT (optimistic_info->references, ref, vn_reference_t, hi)
3145 copy_reference (ref, valid_info);
3147 current_info = valid_info;
3150 DEF_VEC_O(ssa_op_iter);
3151 DEF_VEC_ALLOC_O(ssa_op_iter,heap);
3153 /* Pop the components of the found SCC for NAME off the SCC stack
3154 and process them. Returns true if all went well, false if
3155 we run into resource limits. */
3158 extract_and_process_scc_for_name (tree name)
3160 VEC (tree, heap) *scc = NULL;
3163 /* Found an SCC, pop the components off the SCC stack and
3167 x = VEC_pop (tree, sccstack);
3169 VN_INFO (x)->on_sccstack = false;
3170 VEC_safe_push (tree, heap, scc, x);
3171 } while (x != name);
3173 /* Bail out of SCCVN in case a SCC turns out to be incredibly large. */
3174 if (VEC_length (tree, scc)
3175 > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE))
3178 fprintf (dump_file, "WARNING: Giving up with SCCVN due to "
3179 "SCC size %u exceeding %u\n", VEC_length (tree, scc),
3180 (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE));
3184 if (VEC_length (tree, scc) > 1)
3187 if (dump_file && (dump_flags & TDF_DETAILS))
3188 print_scc (dump_file, scc);
3192 VEC_free (tree, heap, scc);
3197 /* Depth first search on NAME to discover and process SCC's in the SSA
3199 Execution of this algorithm relies on the fact that the SCC's are
3200 popped off the stack in topological order.
3201 Returns true if successful, false if we stopped processing SCC's due
3202 to resource constraints. */
3207 VEC(ssa_op_iter, heap) *itervec = NULL;
3208 VEC(tree, heap) *namevec = NULL;
3209 use_operand_p usep = NULL;
3216 VN_INFO (name)->dfsnum = next_dfs_num++;
3217 VN_INFO (name)->visited = true;
3218 VN_INFO (name)->low = VN_INFO (name)->dfsnum;
3220 VEC_safe_push (tree, heap, sccstack, name);
3221 VN_INFO (name)->on_sccstack = true;
3222 defstmt = SSA_NAME_DEF_STMT (name);
3224 /* Recursively DFS on our operands, looking for SCC's. */
3225 if (!gimple_nop_p (defstmt))
3227 /* Push a new iterator. */
3228 if (gimple_code (defstmt) == GIMPLE_PHI)
3229 usep = op_iter_init_phiuse (&iter, defstmt, SSA_OP_ALL_USES);
3231 usep = op_iter_init_use (&iter, defstmt, SSA_OP_ALL_USES);
3234 clear_and_done_ssa_iter (&iter);
3238 /* If we are done processing uses of a name, go up the stack
3239 of iterators and process SCCs as we found them. */
3240 if (op_iter_done (&iter))
3242 /* See if we found an SCC. */
3243 if (VN_INFO (name)->low == VN_INFO (name)->dfsnum)
3244 if (!extract_and_process_scc_for_name (name))
3246 VEC_free (tree, heap, namevec);
3247 VEC_free (ssa_op_iter, heap, itervec);
3251 /* Check if we are done. */
3252 if (VEC_empty (tree, namevec))
3254 VEC_free (tree, heap, namevec);
3255 VEC_free (ssa_op_iter, heap, itervec);
3259 /* Restore the last use walker and continue walking there. */
3261 name = VEC_pop (tree, namevec);
3262 memcpy (&iter, VEC_last (ssa_op_iter, itervec),
3263 sizeof (ssa_op_iter));
3264 VEC_pop (ssa_op_iter, itervec);
3265 goto continue_walking;
3268 use = USE_FROM_PTR (usep);
3270 /* Since we handle phi nodes, we will sometimes get
3271 invariants in the use expression. */
3272 if (TREE_CODE (use) == SSA_NAME)
3274 if (! (VN_INFO (use)->visited))
3276 /* Recurse by pushing the current use walking state on
3277 the stack and starting over. */
3278 VEC_safe_push(ssa_op_iter, heap, itervec, &iter);
3279 VEC_safe_push(tree, heap, namevec, name);
3284 VN_INFO (name)->low = MIN (VN_INFO (name)->low,
3285 VN_INFO (use)->low);
3287 if (VN_INFO (use)->dfsnum < VN_INFO (name)->dfsnum
3288 && VN_INFO (use)->on_sccstack)
3290 VN_INFO (name)->low = MIN (VN_INFO (use)->dfsnum,
3291 VN_INFO (name)->low);
3295 usep = op_iter_next_use (&iter);
3299 /* Allocate a value number table. */
3302 allocate_vn_table (vn_tables_t table)
3304 table->phis = htab_create (23, vn_phi_hash, vn_phi_eq, free_phi);
3305 table->nary = htab_create (23, vn_nary_op_hash, vn_nary_op_eq, NULL);
3306 table->references = htab_create (23, vn_reference_hash, vn_reference_eq,
3309 gcc_obstack_init (&table->nary_obstack);
3310 table->phis_pool = create_alloc_pool ("VN phis",
3311 sizeof (struct vn_phi_s),
3313 table->references_pool = create_alloc_pool ("VN references",
3314 sizeof (struct vn_reference_s),
3318 /* Free a value number table. */
3321 free_vn_table (vn_tables_t table)
3323 htab_delete (table->phis);
3324 htab_delete (table->nary);
3325 htab_delete (table->references);
3326 obstack_free (&table->nary_obstack, NULL);
3327 free_alloc_pool (table->phis_pool);
3328 free_alloc_pool (table->references_pool);
3336 int *rpo_numbers_temp;
3338 calculate_dominance_info (CDI_DOMINATORS);
3340 constant_to_value_id = htab_create (23, vn_constant_hash, vn_constant_eq,
3343 constant_value_ids = BITMAP_ALLOC (NULL);
3348 vn_ssa_aux_table = VEC_alloc (vn_ssa_aux_t, heap, num_ssa_names + 1);
3349 /* VEC_alloc doesn't actually grow it to the right size, it just
3350 preallocates the space to do so. */
3351 VEC_safe_grow_cleared (vn_ssa_aux_t, heap, vn_ssa_aux_table, num_ssa_names + 1);
3352 gcc_obstack_init (&vn_ssa_aux_obstack);
3354 shared_lookup_phiargs = NULL;
3355 shared_lookup_references = NULL;
3356 rpo_numbers = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3357 rpo_numbers_temp = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3358 pre_and_rev_post_order_compute (NULL, rpo_numbers_temp, false);
3360 /* RPO numbers is an array of rpo ordering, rpo[i] = bb means that
3361 the i'th block in RPO order is bb. We want to map bb's to RPO
3362 numbers, so we need to rearrange this array. */
3363 for (j = 0; j < n_basic_blocks - NUM_FIXED_BLOCKS; j++)
3364 rpo_numbers[rpo_numbers_temp[j]] = j;
3366 XDELETE (rpo_numbers_temp);
3368 VN_TOP = create_tmp_var_raw (void_type_node, "vn_top");
3370 /* Create the VN_INFO structures, and initialize value numbers to
3372 for (i = 0; i < num_ssa_names; i++)
3374 tree name = ssa_name (i);
3377 VN_INFO_GET (name)->valnum = VN_TOP;
3378 VN_INFO (name)->expr = NULL_TREE;
3379 VN_INFO (name)->value_id = 0;
3383 renumber_gimple_stmt_uids ();
3385 /* Create the valid and optimistic value numbering tables. */
3386 valid_info = XCNEW (struct vn_tables_s);
3387 allocate_vn_table (valid_info);
3388 optimistic_info = XCNEW (struct vn_tables_s);
3389 allocate_vn_table (optimistic_info);
3397 htab_delete (constant_to_value_id);
3398 BITMAP_FREE (constant_value_ids);
3399 VEC_free (tree, heap, shared_lookup_phiargs);
3400 VEC_free (vn_reference_op_s, heap, shared_lookup_references);
3401 XDELETEVEC (rpo_numbers);
3403 for (i = 0; i < num_ssa_names; i++)
3405 tree name = ssa_name (i);
3407 && VN_INFO (name)->needs_insertion)
3408 release_ssa_name (name);
3410 obstack_free (&vn_ssa_aux_obstack, NULL);
3411 VEC_free (vn_ssa_aux_t, heap, vn_ssa_aux_table);
3413 VEC_free (tree, heap, sccstack);
3414 free_vn_table (valid_info);
3415 XDELETE (valid_info);
3416 free_vn_table (optimistic_info);
3417 XDELETE (optimistic_info);
3420 /* Set *ID if we computed something useful in RESULT. */
3423 set_value_id_for_result (tree result, unsigned int *id)
3427 if (TREE_CODE (result) == SSA_NAME)
3428 *id = VN_INFO (result)->value_id;
3429 else if (is_gimple_min_invariant (result))
3430 *id = get_or_alloc_constant_value_id (result);
3434 /* Set the value ids in the valid hash tables. */
3437 set_hashtable_value_ids (void)
3444 /* Now set the value ids of the things we had put in the hash
3447 FOR_EACH_HTAB_ELEMENT (valid_info->nary,
3448 vno, vn_nary_op_t, hi)
3449 set_value_id_for_result (vno->result, &vno->value_id);
3451 FOR_EACH_HTAB_ELEMENT (valid_info->phis,
3453 set_value_id_for_result (vp->result, &vp->value_id);
3455 FOR_EACH_HTAB_ELEMENT (valid_info->references,
3456 vr, vn_reference_t, hi)
3457 set_value_id_for_result (vr->result, &vr->value_id);
3460 /* Do SCCVN. Returns true if it finished, false if we bailed out
3461 due to resource constraints. */
3468 bool changed = true;
3471 current_info = valid_info;
3473 for (param = DECL_ARGUMENTS (current_function_decl);
3475 param = DECL_CHAIN (param))
3477 if (gimple_default_def (cfun, param) != NULL)
3479 tree def = gimple_default_def (cfun, param);
3480 VN_INFO (def)->valnum = def;
3484 for (i = 1; i < num_ssa_names; ++i)
3486 tree name = ssa_name (i);
3488 && VN_INFO (name)->visited == false
3489 && !has_zero_uses (name))
3497 /* Initialize the value ids. */
3499 for (i = 1; i < num_ssa_names; ++i)
3501 tree name = ssa_name (i);
3505 info = VN_INFO (name);
3506 if (info->valnum == name
3507 || info->valnum == VN_TOP)
3508 info->value_id = get_next_value_id ();
3509 else if (is_gimple_min_invariant (info->valnum))
3510 info->value_id = get_or_alloc_constant_value_id (info->valnum);
3513 /* Propagate until they stop changing. */
3517 for (i = 1; i < num_ssa_names; ++i)
3519 tree name = ssa_name (i);
3523 info = VN_INFO (name);
3524 if (TREE_CODE (info->valnum) == SSA_NAME
3525 && info->valnum != name
3526 && info->value_id != VN_INFO (info->valnum)->value_id)
3529 info->value_id = VN_INFO (info->valnum)->value_id;
3534 set_hashtable_value_ids ();
3536 if (dump_file && (dump_flags & TDF_DETAILS))
3538 fprintf (dump_file, "Value numbers:\n");
3539 for (i = 0; i < num_ssa_names; i++)
3541 tree name = ssa_name (i);
3543 && VN_INFO (name)->visited
3544 && SSA_VAL (name) != name)
3546 print_generic_expr (dump_file, name, 0);
3547 fprintf (dump_file, " = ");
3548 print_generic_expr (dump_file, SSA_VAL (name), 0);
3549 fprintf (dump_file, "\n");
3557 /* Return the maximum value id we have ever seen. */
3560 get_max_value_id (void)
3562 return next_value_id;
3565 /* Return the next unique value id. */
3568 get_next_value_id (void)
3570 return next_value_id++;
3574 /* Compare two expressions E1 and E2 and return true if they are equal. */
3577 expressions_equal_p (tree e1, tree e2)
3579 /* The obvious case. */
3583 /* If only one of them is null, they cannot be equal. */
3587 /* Now perform the actual comparison. */
3588 if (TREE_CODE (e1) == TREE_CODE (e2)
3589 && operand_equal_p (e1, e2, OEP_PURE_SAME))
3596 /* Return true if the nary operation NARY may trap. This is a copy
3597 of stmt_could_throw_1_p adjusted to the SCCVN IL. */
3600 vn_nary_may_trap (vn_nary_op_t nary)
3603 tree rhs2 = NULL_TREE;
3604 bool honor_nans = false;
3605 bool honor_snans = false;
3606 bool fp_operation = false;
3607 bool honor_trapv = false;
3611 if (TREE_CODE_CLASS (nary->opcode) == tcc_comparison
3612 || TREE_CODE_CLASS (nary->opcode) == tcc_unary
3613 || TREE_CODE_CLASS (nary->opcode) == tcc_binary)
3616 fp_operation = FLOAT_TYPE_P (type);
3619 honor_nans = flag_trapping_math && !flag_finite_math_only;
3620 honor_snans = flag_signaling_nans != 0;
3622 else if (INTEGRAL_TYPE_P (type)
3623 && TYPE_OVERFLOW_TRAPS (type))
3626 if (nary->length >= 2)
3628 ret = operation_could_trap_helper_p (nary->opcode, fp_operation,
3630 honor_nans, honor_snans, rhs2,
3636 for (i = 0; i < nary->length; ++i)
3637 if (tree_could_trap_p (nary->op[i]))