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 (i = 0; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro); i++)
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)))
505 HOST_WIDE_INT off1 = 0, off2 = 0;
506 vn_reference_op_t vro1, vro2;
507 vn_reference_op_s tem1, tem2;
508 bool deref1 = false, deref2 = false;
509 for (; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro1); i++)
511 if (vro1->opcode == MEM_REF)
517 for (; VEC_iterate (vn_reference_op_s, vr2->operands, j, vro2); j++)
519 if (vro2->opcode == MEM_REF)
527 if (deref1 && vro1->opcode == ADDR_EXPR)
529 memset (&tem1, 0, sizeof (tem1));
530 tem1.op0 = TREE_OPERAND (vro1->op0, 0);
531 tem1.type = TREE_TYPE (tem1.op0);
532 tem1.opcode = TREE_CODE (tem1.op0);
535 if (deref2 && vro2->opcode == ADDR_EXPR)
537 memset (&tem2, 0, sizeof (tem2));
538 tem2.op0 = TREE_OPERAND (vro2->op0, 0);
539 tem2.type = TREE_TYPE (tem2.op0);
540 tem2.opcode = TREE_CODE (tem2.op0);
543 if (!vn_reference_op_eq (vro1, vro2))
548 while (VEC_length (vn_reference_op_s, vr1->operands) != i
549 || VEC_length (vn_reference_op_s, vr2->operands) != j);
554 /* Copy the operations present in load/store REF into RESULT, a vector of
555 vn_reference_op_s's. */
558 copy_reference_ops_from_ref (tree ref, VEC(vn_reference_op_s, heap) **result)
560 if (TREE_CODE (ref) == TARGET_MEM_REF)
562 vn_reference_op_s temp;
565 base = TMR_SYMBOL (ref) ? TMR_SYMBOL (ref) : TMR_BASE (ref);
567 base = build_int_cst (ptr_type_node, 0);
569 memset (&temp, 0, sizeof (temp));
570 /* We do not care for spurious type qualifications. */
571 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
572 temp.opcode = TREE_CODE (ref);
573 temp.op0 = TMR_INDEX (ref);
574 temp.op1 = TMR_STEP (ref);
575 temp.op2 = TMR_OFFSET (ref);
577 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
579 memset (&temp, 0, sizeof (temp));
580 temp.type = NULL_TREE;
581 temp.opcode = TREE_CODE (base);
583 temp.op1 = TMR_ORIGINAL (ref);
585 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
589 /* For non-calls, store the information that makes up the address. */
593 vn_reference_op_s temp;
595 memset (&temp, 0, sizeof (temp));
596 /* We do not care for spurious type qualifications. */
597 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
598 temp.opcode = TREE_CODE (ref);
603 case ALIGN_INDIRECT_REF:
604 /* The only operand is the address, which gets its own
605 vn_reference_op_s structure. */
607 case MISALIGNED_INDIRECT_REF:
608 temp.op0 = TREE_OPERAND (ref, 1);
611 /* The base address gets its own vn_reference_op_s structure. */
612 temp.op0 = TREE_OPERAND (ref, 1);
613 if (host_integerp (TREE_OPERAND (ref, 1), 0))
614 temp.off = TREE_INT_CST_LOW (TREE_OPERAND (ref, 1));
617 /* Record bits and position. */
618 temp.op0 = TREE_OPERAND (ref, 1);
619 temp.op1 = TREE_OPERAND (ref, 2);
622 /* The field decl is enough to unambiguously specify the field,
623 a matching type is not necessary and a mismatching type
624 is always a spurious difference. */
625 temp.type = NULL_TREE;
626 temp.op0 = TREE_OPERAND (ref, 1);
627 temp.op1 = TREE_OPERAND (ref, 2);
629 tree this_offset = component_ref_field_offset (ref);
631 && TREE_CODE (this_offset) == INTEGER_CST)
633 tree bit_offset = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1));
634 if (TREE_INT_CST_LOW (bit_offset) % BITS_PER_UNIT == 0)
637 = double_int_add (tree_to_double_int (this_offset),
639 (tree_to_double_int (bit_offset),
640 uhwi_to_double_int (BITS_PER_UNIT),
642 if (double_int_fits_in_shwi_p (off))
648 case ARRAY_RANGE_REF:
650 /* Record index as operand. */
651 temp.op0 = TREE_OPERAND (ref, 1);
652 /* Always record lower bounds and element size. */
653 temp.op1 = array_ref_low_bound (ref);
654 temp.op2 = array_ref_element_size (ref);
655 if (TREE_CODE (temp.op0) == INTEGER_CST
656 && TREE_CODE (temp.op1) == INTEGER_CST
657 && TREE_CODE (temp.op2) == INTEGER_CST)
659 double_int off = tree_to_double_int (temp.op0);
660 off = double_int_add (off,
662 (tree_to_double_int (temp.op1)));
663 off = double_int_mul (off, tree_to_double_int (temp.op2));
664 if (double_int_fits_in_shwi_p (off))
682 if (is_gimple_min_invariant (ref))
688 /* These are only interesting for their operands, their
689 existence, and their type. They will never be the last
690 ref in the chain of references (IE they require an
691 operand), so we don't have to put anything
692 for op* as it will be handled by the iteration */
694 case VIEW_CONVERT_EXPR:
698 /* This is only interesting for its constant offset. */
699 temp.off = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (ref)));
704 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
706 if (REFERENCE_CLASS_P (ref)
707 || (TREE_CODE (ref) == ADDR_EXPR
708 && !is_gimple_min_invariant (ref)))
709 ref = TREE_OPERAND (ref, 0);
715 /* Build a alias-oracle reference abstraction in *REF from the vn_reference
716 operands in *OPS, the reference alias set SET and the reference type TYPE.
717 Return true if something useful was produced. */
720 ao_ref_init_from_vn_reference (ao_ref *ref,
721 alias_set_type set, tree type,
722 VEC (vn_reference_op_s, heap) *ops)
724 vn_reference_op_t op;
726 tree base = NULL_TREE;
728 HOST_WIDE_INT offset = 0;
729 HOST_WIDE_INT max_size;
730 HOST_WIDE_INT size = -1;
731 tree size_tree = NULL_TREE;
732 alias_set_type base_alias_set = -1;
734 /* First get the final access size from just the outermost expression. */
735 op = VEC_index (vn_reference_op_s, ops, 0);
736 if (op->opcode == COMPONENT_REF)
737 size_tree = DECL_SIZE (op->op0);
738 else if (op->opcode == BIT_FIELD_REF)
742 enum machine_mode mode = TYPE_MODE (type);
744 size_tree = TYPE_SIZE (type);
746 size = GET_MODE_BITSIZE (mode);
748 if (size_tree != NULL_TREE)
750 if (!host_integerp (size_tree, 1))
753 size = TREE_INT_CST_LOW (size_tree);
756 /* Initially, maxsize is the same as the accessed element size.
757 In the following it will only grow (or become -1). */
760 /* Compute cumulative bit-offset for nested component-refs and array-refs,
761 and find the ultimate containing object. */
762 for (i = 0; VEC_iterate (vn_reference_op_s, ops, i, op); ++i)
766 /* These may be in the reference ops, but we cannot do anything
767 sensible with them here. */
769 /* Apart from ADDR_EXPR arguments to MEM_REF. */
770 if (base != NULL_TREE
771 && TREE_CODE (base) == MEM_REF
773 && DECL_P (TREE_OPERAND (op->op0, 0)))
775 vn_reference_op_t pop = VEC_index (vn_reference_op_s, ops, i-1);
776 base = TREE_OPERAND (op->op0, 0);
783 offset += pop->off * BITS_PER_UNIT;
791 /* Record the base objects. */
792 case ALIGN_INDIRECT_REF:
793 *op0_p = build1 (op->opcode, op->type, NULL_TREE);
794 op0_p = &TREE_OPERAND (*op0_p, 0);
797 case MISALIGNED_INDIRECT_REF:
798 *op0_p = build2 (MISALIGNED_INDIRECT_REF, op->type,
800 op0_p = &TREE_OPERAND (*op0_p, 0);
804 base_alias_set = get_deref_alias_set (op->op0);
805 *op0_p = build2 (MEM_REF, op->type,
807 op0_p = &TREE_OPERAND (*op0_p, 0);
818 /* And now the usual component-reference style ops. */
820 offset += tree_low_cst (op->op1, 0);
825 tree field = op->op0;
826 /* We do not have a complete COMPONENT_REF tree here so we
827 cannot use component_ref_field_offset. Do the interesting
831 || !host_integerp (DECL_FIELD_OFFSET (field), 1))
835 offset += (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (field))
837 offset += TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
842 case ARRAY_RANGE_REF:
844 /* We recorded the lower bound and the element size. */
845 if (!host_integerp (op->op0, 0)
846 || !host_integerp (op->op1, 0)
847 || !host_integerp (op->op2, 0))
851 HOST_WIDE_INT hindex = TREE_INT_CST_LOW (op->op0);
852 hindex -= TREE_INT_CST_LOW (op->op1);
853 hindex *= TREE_INT_CST_LOW (op->op2);
854 hindex *= BITS_PER_UNIT;
866 case VIEW_CONVERT_EXPR:
883 if (base == NULL_TREE)
886 ref->ref = NULL_TREE;
888 ref->offset = offset;
890 ref->max_size = max_size;
891 ref->ref_alias_set = set;
892 if (base_alias_set != -1)
893 ref->base_alias_set = base_alias_set;
895 ref->base_alias_set = get_alias_set (base);
900 /* Copy the operations present in load/store/call REF into RESULT, a vector of
901 vn_reference_op_s's. */
904 copy_reference_ops_from_call (gimple call,
905 VEC(vn_reference_op_s, heap) **result)
907 vn_reference_op_s temp;
910 /* Copy the type, opcode, function being called and static chain. */
911 memset (&temp, 0, sizeof (temp));
912 temp.type = gimple_call_return_type (call);
913 temp.opcode = CALL_EXPR;
914 temp.op0 = gimple_call_fn (call);
915 temp.op1 = gimple_call_chain (call);
917 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
919 /* Copy the call arguments. As they can be references as well,
920 just chain them together. */
921 for (i = 0; i < gimple_call_num_args (call); ++i)
923 tree callarg = gimple_call_arg (call, i);
924 copy_reference_ops_from_ref (callarg, result);
928 /* Create a vector of vn_reference_op_s structures from REF, a
929 REFERENCE_CLASS_P tree. The vector is not shared. */
931 static VEC(vn_reference_op_s, heap) *
932 create_reference_ops_from_ref (tree ref)
934 VEC (vn_reference_op_s, heap) *result = NULL;
936 copy_reference_ops_from_ref (ref, &result);
940 /* Create a vector of vn_reference_op_s structures from CALL, a
941 call statement. The vector is not shared. */
943 static VEC(vn_reference_op_s, heap) *
944 create_reference_ops_from_call (gimple call)
946 VEC (vn_reference_op_s, heap) *result = NULL;
948 copy_reference_ops_from_call (call, &result);
952 /* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
953 *I_P to point to the last element of the replacement. */
955 vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **ops,
958 unsigned int i = *i_p;
959 vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
960 vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
962 HOST_WIDE_INT addr_offset;
964 /* The only thing we have to do is from &OBJ.foo.bar add the offset
965 from .foo.bar to the preceeding MEM_REF offset and replace the
966 address with &OBJ. */
967 addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (op->op0, 0),
969 gcc_checking_assert (addr_base && TREE_CODE (addr_base) != MEM_REF);
970 if (addr_base != op->op0)
972 double_int off = tree_to_double_int (mem_op->op0);
973 off = double_int_sext (off, TYPE_PRECISION (TREE_TYPE (mem_op->op0)));
974 off = double_int_add (off, shwi_to_double_int (addr_offset));
975 mem_op->op0 = double_int_to_tree (TREE_TYPE (mem_op->op0), off);
976 op->op0 = build_fold_addr_expr (addr_base);
977 if (host_integerp (mem_op->op0, 0))
978 mem_op->off = TREE_INT_CST_LOW (mem_op->op0);
984 /* Optimize the reference REF to a constant if possible or return
988 fully_constant_vn_reference_p (vn_reference_t ref)
990 VEC (vn_reference_op_s, heap) *operands = ref->operands;
991 vn_reference_op_t op;
993 /* Try to simplify the translated expression if it is
994 a call to a builtin function with at most two arguments. */
995 op = VEC_index (vn_reference_op_s, operands, 0);
996 if (op->opcode == CALL_EXPR
997 && TREE_CODE (op->op0) == ADDR_EXPR
998 && TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
999 && DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
1000 && VEC_length (vn_reference_op_s, operands) >= 2
1001 && VEC_length (vn_reference_op_s, operands) <= 3)
1003 vn_reference_op_t arg0, arg1 = NULL;
1004 bool anyconst = false;
1005 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1006 if (VEC_length (vn_reference_op_s, operands) > 2)
1007 arg1 = VEC_index (vn_reference_op_s, operands, 2);
1008 if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
1009 || (arg0->opcode == ADDR_EXPR
1010 && is_gimple_min_invariant (arg0->op0)))
1013 && (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
1014 || (arg1->opcode == ADDR_EXPR
1015 && is_gimple_min_invariant (arg1->op0))))
1019 tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
1022 arg1 ? arg1->op0 : NULL);
1024 && TREE_CODE (folded) == NOP_EXPR)
1025 folded = TREE_OPERAND (folded, 0);
1027 && is_gimple_min_invariant (folded))
1032 /* Simplify reads from constant strings. */
1033 else if (op->opcode == ARRAY_REF
1034 && TREE_CODE (op->op0) == INTEGER_CST
1035 && integer_zerop (op->op1)
1036 && VEC_length (vn_reference_op_s, operands) == 2)
1038 vn_reference_op_t arg0;
1039 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1040 if (arg0->opcode == STRING_CST
1041 && (TYPE_MODE (op->type)
1042 == TYPE_MODE (TREE_TYPE (TREE_TYPE (arg0->op0))))
1043 && GET_MODE_CLASS (TYPE_MODE (op->type)) == MODE_INT
1044 && GET_MODE_SIZE (TYPE_MODE (op->type)) == 1
1045 && compare_tree_int (op->op0, TREE_STRING_LENGTH (arg0->op0)) < 0)
1046 return build_int_cst_type (op->type,
1047 (TREE_STRING_POINTER (arg0->op0)
1048 [TREE_INT_CST_LOW (op->op0)]));
1054 /* Transform any SSA_NAME's in a vector of vn_reference_op_s
1055 structures into their value numbers. This is done in-place, and
1056 the vector passed in is returned. */
1058 static VEC (vn_reference_op_s, heap) *
1059 valueize_refs (VEC (vn_reference_op_s, heap) *orig)
1061 vn_reference_op_t vro;
1064 for (i = 0; VEC_iterate (vn_reference_op_s, orig, i, vro); i++)
1066 if (vro->opcode == SSA_NAME
1067 || (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME))
1069 vro->op0 = SSA_VAL (vro->op0);
1070 /* If it transforms from an SSA_NAME to a constant, update
1072 if (TREE_CODE (vro->op0) != SSA_NAME && vro->opcode == SSA_NAME)
1073 vro->opcode = TREE_CODE (vro->op0);
1075 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1076 vro->op1 = SSA_VAL (vro->op1);
1077 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
1078 vro->op2 = SSA_VAL (vro->op2);
1079 /* If it transforms from an SSA_NAME to an address, fold with
1080 a preceding indirect reference. */
1083 && TREE_CODE (vro->op0) == ADDR_EXPR
1084 && VEC_index (vn_reference_op_s,
1085 orig, i - 1)->opcode == MEM_REF)
1086 vn_reference_fold_indirect (&orig, &i);
1087 /* If it transforms a non-constant ARRAY_REF into a constant
1088 one, adjust the constant offset. */
1089 else if (vro->opcode == ARRAY_REF
1091 && TREE_CODE (vro->op0) == INTEGER_CST
1092 && TREE_CODE (vro->op1) == INTEGER_CST
1093 && TREE_CODE (vro->op2) == INTEGER_CST)
1095 double_int off = tree_to_double_int (vro->op0);
1096 off = double_int_add (off,
1098 (tree_to_double_int (vro->op1)));
1099 off = double_int_mul (off, tree_to_double_int (vro->op2));
1100 if (double_int_fits_in_shwi_p (off))
1108 static VEC(vn_reference_op_s, heap) *shared_lookup_references;
1110 /* Create a vector of vn_reference_op_s structures from REF, a
1111 REFERENCE_CLASS_P tree. The vector is shared among all callers of
1114 static VEC(vn_reference_op_s, heap) *
1115 valueize_shared_reference_ops_from_ref (tree ref)
1119 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1120 copy_reference_ops_from_ref (ref, &shared_lookup_references);
1121 shared_lookup_references = valueize_refs (shared_lookup_references);
1122 return shared_lookup_references;
1125 /* Create a vector of vn_reference_op_s structures from CALL, a
1126 call statement. The vector is shared among all callers of
1129 static VEC(vn_reference_op_s, heap) *
1130 valueize_shared_reference_ops_from_call (gimple call)
1134 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1135 copy_reference_ops_from_call (call, &shared_lookup_references);
1136 shared_lookup_references = valueize_refs (shared_lookup_references);
1137 return shared_lookup_references;
1140 /* Lookup a SCCVN reference operation VR in the current hash table.
1141 Returns the resulting value number if it exists in the hash table,
1142 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1143 vn_reference_t stored in the hashtable if something is found. */
1146 vn_reference_lookup_1 (vn_reference_t vr, vn_reference_t *vnresult)
1151 hash = vr->hashcode;
1152 slot = htab_find_slot_with_hash (current_info->references, vr,
1154 if (!slot && current_info == optimistic_info)
1155 slot = htab_find_slot_with_hash (valid_info->references, vr,
1160 *vnresult = (vn_reference_t)*slot;
1161 return ((vn_reference_t)*slot)->result;
1167 static tree *last_vuse_ptr;
1169 /* Callback for walk_non_aliased_vuses. Adjusts the vn_reference_t VR_
1170 with the current VUSE and performs the expression lookup. */
1173 vn_reference_lookup_2 (ao_ref *op ATTRIBUTE_UNUSED, tree vuse, void *vr_)
1175 vn_reference_t vr = (vn_reference_t)vr_;
1180 *last_vuse_ptr = vuse;
1182 /* Fixup vuse and hash. */
1184 vr->hashcode = vr->hashcode - SSA_NAME_VERSION (vr->vuse);
1185 vr->vuse = SSA_VAL (vuse);
1187 vr->hashcode = vr->hashcode + SSA_NAME_VERSION (vr->vuse);
1189 hash = vr->hashcode;
1190 slot = htab_find_slot_with_hash (current_info->references, vr,
1192 if (!slot && current_info == optimistic_info)
1193 slot = htab_find_slot_with_hash (valid_info->references, vr,
1201 /* Callback for walk_non_aliased_vuses. Tries to perform a lookup
1202 from the statement defining VUSE and if not successful tries to
1203 translate *REFP and VR_ through an aggregate copy at the defintion
1207 vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
1209 vn_reference_t vr = (vn_reference_t)vr_;
1210 gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
1213 HOST_WIDE_INT offset, maxsize;
1215 base = ao_ref_base (ref);
1216 offset = ref->offset;
1217 maxsize = ref->max_size;
1219 /* If we cannot constrain the size of the reference we cannot
1220 test if anything kills it. */
1224 /* def_stmt may-defs *ref. See if we can derive a value for *ref
1225 from that defintion.
1227 if (is_gimple_reg_type (vr->type)
1228 && is_gimple_call (def_stmt)
1229 && (fndecl = gimple_call_fndecl (def_stmt))
1230 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
1231 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET
1232 && integer_zerop (gimple_call_arg (def_stmt, 1))
1233 && host_integerp (gimple_call_arg (def_stmt, 2), 1)
1234 && TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR)
1236 tree ref2 = TREE_OPERAND (gimple_call_arg (def_stmt, 0), 0);
1238 HOST_WIDE_INT offset2, size2, maxsize2;
1239 base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &maxsize2);
1240 size2 = TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2)) * 8;
1241 if ((unsigned HOST_WIDE_INT)size2 / 8
1242 == TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2))
1243 && operand_equal_p (base, base2, 0)
1244 && offset2 <= offset
1245 && offset2 + size2 >= offset + maxsize)
1247 tree val = fold_convert (vr->type, integer_zero_node);
1248 unsigned int value_id = get_or_alloc_constant_value_id (val);
1249 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1250 VEC_copy (vn_reference_op_s,
1251 heap, vr->operands),
1256 /* 2) Assignment from an empty CONSTRUCTOR. */
1257 else if (is_gimple_reg_type (vr->type)
1258 && gimple_assign_single_p (def_stmt)
1259 && gimple_assign_rhs_code (def_stmt) == CONSTRUCTOR
1260 && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (def_stmt)) == 0)
1263 HOST_WIDE_INT offset2, size2, maxsize2;
1264 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1265 &offset2, &size2, &maxsize2);
1266 if (operand_equal_p (base, base2, 0)
1267 && offset2 <= offset
1268 && offset2 + size2 >= offset + maxsize)
1270 tree val = fold_convert (vr->type, integer_zero_node);
1271 unsigned int value_id = get_or_alloc_constant_value_id (val);
1272 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1273 VEC_copy (vn_reference_op_s,
1274 heap, vr->operands),
1279 /* For aggregate copies translate the reference through them if
1280 the copy kills ref. */
1281 else if (gimple_assign_single_p (def_stmt)
1282 && (DECL_P (gimple_assign_rhs1 (def_stmt))
1283 || TREE_CODE (gimple_assign_rhs1 (def_stmt)) == MEM_REF
1284 || handled_component_p (gimple_assign_rhs1 (def_stmt))))
1287 HOST_WIDE_INT offset2, size2, maxsize2;
1289 VEC (vn_reference_op_s, heap) *lhs = NULL, *rhs = NULL;
1290 vn_reference_op_t vro;
1293 /* See if the assignment kills REF. */
1294 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1295 &offset2, &size2, &maxsize2);
1296 if (!operand_equal_p (base, base2, 0)
1298 || offset2 + size2 < offset + maxsize)
1301 /* Find the common base of ref and the lhs. */
1302 copy_reference_ops_from_ref (gimple_assign_lhs (def_stmt), &lhs);
1303 i = VEC_length (vn_reference_op_s, vr->operands) - 1;
1304 j = VEC_length (vn_reference_op_s, lhs) - 1;
1305 while (j >= 0 && i >= 0
1306 && vn_reference_op_eq (VEC_index (vn_reference_op_s,
1308 VEC_index (vn_reference_op_s, lhs, j)))
1314 VEC_free (vn_reference_op_s, heap, lhs);
1315 /* i now points to the first additional op.
1316 ??? LHS may not be completely contained in VR, one or more
1317 VIEW_CONVERT_EXPRs could be in its way. We could at least
1318 try handling outermost VIEW_CONVERT_EXPRs. */
1322 /* Now re-write REF to be based on the rhs of the assignment. */
1323 copy_reference_ops_from_ref (gimple_assign_rhs1 (def_stmt), &rhs);
1324 /* We need to pre-pend vr->operands[0..i] to rhs. */
1325 if (i + 1 + VEC_length (vn_reference_op_s, rhs)
1326 > VEC_length (vn_reference_op_s, vr->operands))
1328 VEC (vn_reference_op_s, heap) *old = vr->operands;
1329 VEC_safe_grow (vn_reference_op_s, heap, vr->operands,
1330 i + 1 + VEC_length (vn_reference_op_s, rhs));
1331 if (old == shared_lookup_references
1332 && vr->operands != old)
1333 shared_lookup_references = NULL;
1336 VEC_truncate (vn_reference_op_s, vr->operands,
1337 i + 1 + VEC_length (vn_reference_op_s, rhs));
1338 for (j = 0; VEC_iterate (vn_reference_op_s, rhs, j, vro); ++j)
1339 VEC_replace (vn_reference_op_s, vr->operands, i + 1 + j, vro);
1340 VEC_free (vn_reference_op_s, heap, rhs);
1341 vr->hashcode = vn_reference_compute_hash (vr);
1343 /* Adjust *ref from the new operands. */
1344 if (!ao_ref_init_from_vn_reference (&r, vr->set, vr->type, vr->operands))
1346 /* This can happen with bitfields. */
1347 if (ref->size != r.size)
1351 /* Do not update last seen VUSE after translating. */
1352 last_vuse_ptr = NULL;
1354 /* Keep looking for the adjusted *REF / VR pair. */
1358 /* Bail out and stop walking. */
1362 /* Lookup a reference operation by it's parts, in the current hash table.
1363 Returns the resulting value number if it exists in the hash table,
1364 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1365 vn_reference_t stored in the hashtable if something is found. */
1368 vn_reference_lookup_pieces (tree vuse, alias_set_type set, tree type,
1369 VEC (vn_reference_op_s, heap) *operands,
1370 vn_reference_t *vnresult, bool maywalk)
1372 struct vn_reference_s vr1;
1380 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1381 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1382 VEC_safe_grow (vn_reference_op_s, heap, shared_lookup_references,
1383 VEC_length (vn_reference_op_s, operands));
1384 memcpy (VEC_address (vn_reference_op_s, shared_lookup_references),
1385 VEC_address (vn_reference_op_s, operands),
1386 sizeof (vn_reference_op_s)
1387 * VEC_length (vn_reference_op_s, operands));
1388 vr1.operands = operands = shared_lookup_references
1389 = valueize_refs (shared_lookup_references);
1392 vr1.hashcode = vn_reference_compute_hash (&vr1);
1393 if ((cst = fully_constant_vn_reference_p (&vr1)))
1396 vn_reference_lookup_1 (&vr1, vnresult);
1402 if (ao_ref_init_from_vn_reference (&r, set, type, vr1.operands))
1404 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1405 vn_reference_lookup_2,
1406 vn_reference_lookup_3, &vr1);
1407 if (vr1.operands != operands)
1408 VEC_free (vn_reference_op_s, heap, vr1.operands);
1412 return (*vnresult)->result;
1417 /* Lookup OP in the current hash table, and return the resulting value
1418 number if it exists in the hash table. Return NULL_TREE if it does
1419 not exist in the hash table or if the result field of the structure
1420 was NULL.. VNRESULT will be filled in with the vn_reference_t
1421 stored in the hashtable if one exists. */
1424 vn_reference_lookup (tree op, tree vuse, bool maywalk,
1425 vn_reference_t *vnresult)
1427 VEC (vn_reference_op_s, heap) *operands;
1428 struct vn_reference_s vr1;
1434 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1435 vr1.operands = operands = valueize_shared_reference_ops_from_ref (op);
1436 vr1.type = TREE_TYPE (op);
1437 vr1.set = get_alias_set (op);
1438 vr1.hashcode = vn_reference_compute_hash (&vr1);
1439 if ((cst = fully_constant_vn_reference_p (&vr1)))
1445 vn_reference_t wvnresult;
1447 ao_ref_init (&r, op);
1449 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1450 vn_reference_lookup_2,
1451 vn_reference_lookup_3, &vr1);
1452 if (vr1.operands != operands)
1453 VEC_free (vn_reference_op_s, heap, vr1.operands);
1457 *vnresult = wvnresult;
1458 return wvnresult->result;
1464 return vn_reference_lookup_1 (&vr1, vnresult);
1468 /* Insert OP into the current hash table with a value number of
1469 RESULT, and return the resulting reference structure we created. */
1472 vn_reference_insert (tree op, tree result, tree vuse)
1477 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1478 if (TREE_CODE (result) == SSA_NAME)
1479 vr1->value_id = VN_INFO (result)->value_id;
1481 vr1->value_id = get_or_alloc_constant_value_id (result);
1482 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1483 vr1->operands = valueize_refs (create_reference_ops_from_ref (op));
1484 vr1->type = TREE_TYPE (op);
1485 vr1->set = get_alias_set (op);
1486 vr1->hashcode = vn_reference_compute_hash (vr1);
1487 vr1->result = TREE_CODE (result) == SSA_NAME ? SSA_VAL (result) : result;
1489 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1492 /* Because we lookup stores using vuses, and value number failures
1493 using the vdefs (see visit_reference_op_store for how and why),
1494 it's possible that on failure we may try to insert an already
1495 inserted store. This is not wrong, there is no ssa name for a
1496 store that we could use as a differentiator anyway. Thus, unlike
1497 the other lookup functions, you cannot gcc_assert (!*slot)
1500 /* But free the old slot in case of a collision. */
1502 free_reference (*slot);
1508 /* Insert a reference by it's pieces into the current hash table with
1509 a value number of RESULT. Return the resulting reference
1510 structure we created. */
1513 vn_reference_insert_pieces (tree vuse, alias_set_type set, tree type,
1514 VEC (vn_reference_op_s, heap) *operands,
1515 tree result, unsigned int value_id)
1521 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1522 vr1->value_id = value_id;
1523 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1524 vr1->operands = valueize_refs (operands);
1527 vr1->hashcode = vn_reference_compute_hash (vr1);
1528 if (result && TREE_CODE (result) == SSA_NAME)
1529 result = SSA_VAL (result);
1530 vr1->result = result;
1532 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1535 /* At this point we should have all the things inserted that we have
1536 seen before, and we should never try inserting something that
1538 gcc_assert (!*slot);
1540 free_reference (*slot);
1546 /* Compute and return the hash value for nary operation VBO1. */
1549 vn_nary_op_compute_hash (const vn_nary_op_t vno1)
1554 for (i = 0; i < vno1->length; ++i)
1555 if (TREE_CODE (vno1->op[i]) == SSA_NAME)
1556 vno1->op[i] = SSA_VAL (vno1->op[i]);
1558 if (vno1->length == 2
1559 && commutative_tree_code (vno1->opcode)
1560 && tree_swap_operands_p (vno1->op[0], vno1->op[1], false))
1562 tree temp = vno1->op[0];
1563 vno1->op[0] = vno1->op[1];
1567 hash = iterative_hash_hashval_t (vno1->opcode, 0);
1568 for (i = 0; i < vno1->length; ++i)
1569 hash = iterative_hash_expr (vno1->op[i], hash);
1574 /* Return the computed hashcode for nary operation P1. */
1577 vn_nary_op_hash (const void *p1)
1579 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1580 return vno1->hashcode;
1583 /* Compare nary operations P1 and P2 and return true if they are
1587 vn_nary_op_eq (const void *p1, const void *p2)
1589 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1590 const_vn_nary_op_t const vno2 = (const_vn_nary_op_t) p2;
1593 if (vno1->hashcode != vno2->hashcode)
1596 if (vno1->opcode != vno2->opcode
1597 || !types_compatible_p (vno1->type, vno2->type))
1600 for (i = 0; i < vno1->length; ++i)
1601 if (!expressions_equal_p (vno1->op[i], vno2->op[i]))
1607 /* Lookup a n-ary operation by its pieces and return the resulting value
1608 number if it exists in the hash table. Return NULL_TREE if it does
1609 not exist in the hash table or if the result field of the operation
1610 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1614 vn_nary_op_lookup_pieces (unsigned int length, enum tree_code code,
1615 tree type, tree op0, tree op1, tree op2,
1616 tree op3, vn_nary_op_t *vnresult)
1619 struct vn_nary_op_s vno1;
1623 vno1.length = length;
1629 vno1.hashcode = vn_nary_op_compute_hash (&vno1);
1630 slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode,
1632 if (!slot && current_info == optimistic_info)
1633 slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode,
1638 *vnresult = (vn_nary_op_t)*slot;
1639 return ((vn_nary_op_t)*slot)->result;
1642 /* Lookup OP in the current hash table, and return the resulting value
1643 number if it exists in the hash table. Return NULL_TREE if it does
1644 not exist in the hash table or if the result field of the operation
1645 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1649 vn_nary_op_lookup (tree op, vn_nary_op_t *vnresult)
1652 struct vn_nary_op_s vno1;
1657 vno1.opcode = TREE_CODE (op);
1658 vno1.length = TREE_CODE_LENGTH (TREE_CODE (op));
1659 vno1.type = TREE_TYPE (op);
1660 for (i = 0; i < vno1.length; ++i)
1661 vno1.op[i] = TREE_OPERAND (op, i);
1662 vno1.hashcode = vn_nary_op_compute_hash (&vno1);
1663 slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode,
1665 if (!slot && current_info == optimistic_info)
1666 slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode,
1671 *vnresult = (vn_nary_op_t)*slot;
1672 return ((vn_nary_op_t)*slot)->result;
1675 /* Lookup the rhs of STMT in the current hash table, and return the resulting
1676 value number if it exists in the hash table. Return NULL_TREE if
1677 it does not exist in the hash table. VNRESULT will contain the
1678 vn_nary_op_t from the hashtable if it exists. */
1681 vn_nary_op_lookup_stmt (gimple stmt, vn_nary_op_t *vnresult)
1684 struct vn_nary_op_s vno1;
1689 vno1.opcode = gimple_assign_rhs_code (stmt);
1690 vno1.length = gimple_num_ops (stmt) - 1;
1691 vno1.type = gimple_expr_type (stmt);
1692 for (i = 0; i < vno1.length; ++i)
1693 vno1.op[i] = gimple_op (stmt, i + 1);
1694 if (vno1.opcode == REALPART_EXPR
1695 || vno1.opcode == IMAGPART_EXPR
1696 || vno1.opcode == VIEW_CONVERT_EXPR)
1697 vno1.op[0] = TREE_OPERAND (vno1.op[0], 0);
1698 vno1.hashcode = vn_nary_op_compute_hash (&vno1);
1699 slot = htab_find_slot_with_hash (current_info->nary, &vno1, vno1.hashcode,
1701 if (!slot && current_info == optimistic_info)
1702 slot = htab_find_slot_with_hash (valid_info->nary, &vno1, vno1.hashcode,
1707 *vnresult = (vn_nary_op_t)*slot;
1708 return ((vn_nary_op_t)*slot)->result;
1711 /* Insert a n-ary operation into the current hash table using it's
1712 pieces. Return the vn_nary_op_t structure we created and put in
1716 vn_nary_op_insert_pieces (unsigned int length, enum tree_code code,
1717 tree type, tree op0,
1718 tree op1, tree op2, tree op3,
1720 unsigned int value_id)
1725 vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack,
1726 (sizeof (struct vn_nary_op_s)
1727 - sizeof (tree) * (4 - length)));
1728 vno1->value_id = value_id;
1729 vno1->opcode = code;
1730 vno1->length = length;
1740 vno1->result = result;
1741 vno1->hashcode = vn_nary_op_compute_hash (vno1);
1742 slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode,
1744 gcc_assert (!*slot);
1751 /* Insert OP into the current hash table with a value number of
1752 RESULT. Return the vn_nary_op_t structure we created and put in
1756 vn_nary_op_insert (tree op, tree result)
1758 unsigned length = TREE_CODE_LENGTH (TREE_CODE (op));
1763 vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack,
1764 (sizeof (struct vn_nary_op_s)
1765 - sizeof (tree) * (4 - length)));
1766 vno1->value_id = VN_INFO (result)->value_id;
1767 vno1->opcode = TREE_CODE (op);
1768 vno1->length = length;
1769 vno1->type = TREE_TYPE (op);
1770 for (i = 0; i < vno1->length; ++i)
1771 vno1->op[i] = TREE_OPERAND (op, i);
1772 vno1->result = result;
1773 vno1->hashcode = vn_nary_op_compute_hash (vno1);
1774 slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode,
1776 gcc_assert (!*slot);
1782 /* Insert the rhs of STMT into the current hash table with a value number of
1786 vn_nary_op_insert_stmt (gimple stmt, tree result)
1788 unsigned length = gimple_num_ops (stmt) - 1;
1793 vno1 = (vn_nary_op_t) obstack_alloc (¤t_info->nary_obstack,
1794 (sizeof (struct vn_nary_op_s)
1795 - sizeof (tree) * (4 - length)));
1796 vno1->value_id = VN_INFO (result)->value_id;
1797 vno1->opcode = gimple_assign_rhs_code (stmt);
1798 vno1->length = length;
1799 vno1->type = gimple_expr_type (stmt);
1800 for (i = 0; i < vno1->length; ++i)
1801 vno1->op[i] = gimple_op (stmt, i + 1);
1802 if (vno1->opcode == REALPART_EXPR
1803 || vno1->opcode == IMAGPART_EXPR
1804 || vno1->opcode == VIEW_CONVERT_EXPR)
1805 vno1->op[0] = TREE_OPERAND (vno1->op[0], 0);
1806 vno1->result = result;
1807 vno1->hashcode = vn_nary_op_compute_hash (vno1);
1808 slot = htab_find_slot_with_hash (current_info->nary, vno1, vno1->hashcode,
1810 gcc_assert (!*slot);
1816 /* Compute a hashcode for PHI operation VP1 and return it. */
1818 static inline hashval_t
1819 vn_phi_compute_hash (vn_phi_t vp1)
1826 result = vp1->block->index;
1828 /* If all PHI arguments are constants we need to distinguish
1829 the PHI node via its type. */
1830 type = TREE_TYPE (VEC_index (tree, vp1->phiargs, 0));
1831 result += (INTEGRAL_TYPE_P (type)
1832 + (INTEGRAL_TYPE_P (type)
1833 ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
1835 for (i = 0; VEC_iterate (tree, vp1->phiargs, i, phi1op); i++)
1837 if (phi1op == VN_TOP)
1839 result = iterative_hash_expr (phi1op, result);
1845 /* Return the computed hashcode for phi operation P1. */
1848 vn_phi_hash (const void *p1)
1850 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1851 return vp1->hashcode;
1854 /* Compare two phi entries for equality, ignoring VN_TOP arguments. */
1857 vn_phi_eq (const void *p1, const void *p2)
1859 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1860 const_vn_phi_t const vp2 = (const_vn_phi_t) p2;
1862 if (vp1->hashcode != vp2->hashcode)
1865 if (vp1->block == vp2->block)
1870 /* If the PHI nodes do not have compatible types
1871 they are not the same. */
1872 if (!types_compatible_p (TREE_TYPE (VEC_index (tree, vp1->phiargs, 0)),
1873 TREE_TYPE (VEC_index (tree, vp2->phiargs, 0))))
1876 /* Any phi in the same block will have it's arguments in the
1877 same edge order, because of how we store phi nodes. */
1878 for (i = 0; VEC_iterate (tree, vp1->phiargs, i, phi1op); i++)
1880 tree phi2op = VEC_index (tree, vp2->phiargs, i);
1881 if (phi1op == VN_TOP || phi2op == VN_TOP)
1883 if (!expressions_equal_p (phi1op, phi2op))
1891 static VEC(tree, heap) *shared_lookup_phiargs;
1893 /* Lookup PHI in the current hash table, and return the resulting
1894 value number if it exists in the hash table. Return NULL_TREE if
1895 it does not exist in the hash table. */
1898 vn_phi_lookup (gimple phi)
1901 struct vn_phi_s vp1;
1904 VEC_truncate (tree, shared_lookup_phiargs, 0);
1906 /* Canonicalize the SSA_NAME's to their value number. */
1907 for (i = 0; i < gimple_phi_num_args (phi); i++)
1909 tree def = PHI_ARG_DEF (phi, i);
1910 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
1911 VEC_safe_push (tree, heap, shared_lookup_phiargs, def);
1913 vp1.phiargs = shared_lookup_phiargs;
1914 vp1.block = gimple_bb (phi);
1915 vp1.hashcode = vn_phi_compute_hash (&vp1);
1916 slot = htab_find_slot_with_hash (current_info->phis, &vp1, vp1.hashcode,
1918 if (!slot && current_info == optimistic_info)
1919 slot = htab_find_slot_with_hash (valid_info->phis, &vp1, vp1.hashcode,
1923 return ((vn_phi_t)*slot)->result;
1926 /* Insert PHI into the current hash table with a value number of
1930 vn_phi_insert (gimple phi, tree result)
1933 vn_phi_t vp1 = (vn_phi_t) pool_alloc (current_info->phis_pool);
1935 VEC (tree, heap) *args = NULL;
1937 /* Canonicalize the SSA_NAME's to their value number. */
1938 for (i = 0; i < gimple_phi_num_args (phi); i++)
1940 tree def = PHI_ARG_DEF (phi, i);
1941 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
1942 VEC_safe_push (tree, heap, args, def);
1944 vp1->value_id = VN_INFO (result)->value_id;
1945 vp1->phiargs = args;
1946 vp1->block = gimple_bb (phi);
1947 vp1->result = result;
1948 vp1->hashcode = vn_phi_compute_hash (vp1);
1950 slot = htab_find_slot_with_hash (current_info->phis, vp1, vp1->hashcode,
1953 /* Because we iterate over phi operations more than once, it's
1954 possible the slot might already exist here, hence no assert.*/
1960 /* Print set of components in strongly connected component SCC to OUT. */
1963 print_scc (FILE *out, VEC (tree, heap) *scc)
1968 fprintf (out, "SCC consists of: ");
1969 for (i = 0; VEC_iterate (tree, scc, i, var); i++)
1971 print_generic_expr (out, var, 0);
1974 fprintf (out, "\n");
1977 /* Set the value number of FROM to TO, return true if it has changed
1981 set_ssa_val_to (tree from, tree to)
1986 && TREE_CODE (to) == SSA_NAME
1987 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to))
1990 /* The only thing we allow as value numbers are VN_TOP, ssa_names
1991 and invariants. So assert that here. */
1992 gcc_assert (to != NULL_TREE
1994 || TREE_CODE (to) == SSA_NAME
1995 || is_gimple_min_invariant (to)));
1997 if (dump_file && (dump_flags & TDF_DETAILS))
1999 fprintf (dump_file, "Setting value number of ");
2000 print_generic_expr (dump_file, from, 0);
2001 fprintf (dump_file, " to ");
2002 print_generic_expr (dump_file, to, 0);
2005 currval = SSA_VAL (from);
2007 if (currval != to && !operand_equal_p (currval, to, OEP_PURE_SAME))
2009 VN_INFO (from)->valnum = to;
2010 if (dump_file && (dump_flags & TDF_DETAILS))
2011 fprintf (dump_file, " (changed)\n");
2014 if (dump_file && (dump_flags & TDF_DETAILS))
2015 fprintf (dump_file, "\n");
2019 /* Set all definitions in STMT to value number to themselves.
2020 Return true if a value number changed. */
2023 defs_to_varying (gimple stmt)
2025 bool changed = false;
2029 FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_ALL_DEFS)
2031 tree def = DEF_FROM_PTR (defp);
2033 VN_INFO (def)->use_processed = true;
2034 changed |= set_ssa_val_to (def, def);
2039 static bool expr_has_constants (tree expr);
2040 static tree valueize_expr (tree expr);
2042 /* Visit a copy between LHS and RHS, return true if the value number
2046 visit_copy (tree lhs, tree rhs)
2048 /* Follow chains of copies to their destination. */
2049 while (TREE_CODE (rhs) == SSA_NAME
2050 && SSA_VAL (rhs) != rhs)
2051 rhs = SSA_VAL (rhs);
2053 /* The copy may have a more interesting constant filled expression
2054 (we don't, since we know our RHS is just an SSA name). */
2055 if (TREE_CODE (rhs) == SSA_NAME)
2057 VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants;
2058 VN_INFO (lhs)->expr = VN_INFO (rhs)->expr;
2061 return set_ssa_val_to (lhs, rhs);
2064 /* Visit a unary operator RHS, value number it, and return true if the
2065 value number of LHS has changed as a result. */
2068 visit_unary_op (tree lhs, gimple stmt)
2070 bool changed = false;
2071 tree result = vn_nary_op_lookup_stmt (stmt, NULL);
2075 changed = set_ssa_val_to (lhs, result);
2079 changed = set_ssa_val_to (lhs, lhs);
2080 vn_nary_op_insert_stmt (stmt, lhs);
2086 /* Visit a binary operator RHS, value number it, and return true if the
2087 value number of LHS has changed as a result. */
2090 visit_binary_op (tree lhs, gimple stmt)
2092 bool changed = false;
2093 tree result = vn_nary_op_lookup_stmt (stmt, NULL);
2097 changed = set_ssa_val_to (lhs, result);
2101 changed = set_ssa_val_to (lhs, lhs);
2102 vn_nary_op_insert_stmt (stmt, lhs);
2108 /* Visit a call STMT storing into LHS. Return true if the value number
2109 of the LHS has changed as a result. */
2112 visit_reference_op_call (tree lhs, gimple stmt)
2114 bool changed = false;
2115 struct vn_reference_s vr1;
2117 tree vuse = gimple_vuse (stmt);
2119 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
2120 vr1.operands = valueize_shared_reference_ops_from_call (stmt);
2121 vr1.type = gimple_expr_type (stmt);
2123 vr1.hashcode = vn_reference_compute_hash (&vr1);
2124 result = vn_reference_lookup_1 (&vr1, NULL);
2127 changed = set_ssa_val_to (lhs, result);
2128 if (TREE_CODE (result) == SSA_NAME
2129 && VN_INFO (result)->has_constants)
2130 VN_INFO (lhs)->has_constants = true;
2136 changed = set_ssa_val_to (lhs, lhs);
2137 vr2 = (vn_reference_t) pool_alloc (current_info->references_pool);
2138 vr2->vuse = vr1.vuse;
2139 vr2->operands = valueize_refs (create_reference_ops_from_call (stmt));
2140 vr2->type = vr1.type;
2142 vr2->hashcode = vr1.hashcode;
2144 slot = htab_find_slot_with_hash (current_info->references,
2145 vr2, vr2->hashcode, INSERT);
2147 free_reference (*slot);
2154 /* Visit a load from a reference operator RHS, part of STMT, value number it,
2155 and return true if the value number of the LHS has changed as a result. */
2158 visit_reference_op_load (tree lhs, tree op, gimple stmt)
2160 bool changed = false;
2164 last_vuse = gimple_vuse (stmt);
2165 last_vuse_ptr = &last_vuse;
2166 result = vn_reference_lookup (op, gimple_vuse (stmt), true, NULL);
2167 last_vuse_ptr = NULL;
2169 /* If we have a VCE, try looking up its operand as it might be stored in
2170 a different type. */
2171 if (!result && TREE_CODE (op) == VIEW_CONVERT_EXPR)
2172 result = vn_reference_lookup (TREE_OPERAND (op, 0), gimple_vuse (stmt),
2175 /* We handle type-punning through unions by value-numbering based
2176 on offset and size of the access. Be prepared to handle a
2177 type-mismatch here via creating a VIEW_CONVERT_EXPR. */
2179 && !useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (op)))
2181 /* We will be setting the value number of lhs to the value number
2182 of VIEW_CONVERT_EXPR <TREE_TYPE (result)> (result).
2183 So first simplify and lookup this expression to see if it
2184 is already available. */
2185 tree val = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (op), result);
2186 if ((CONVERT_EXPR_P (val)
2187 || TREE_CODE (val) == VIEW_CONVERT_EXPR)
2188 && TREE_CODE (TREE_OPERAND (val, 0)) == SSA_NAME)
2190 tree tem = valueize_expr (vn_get_expr_for (TREE_OPERAND (val, 0)));
2191 if ((CONVERT_EXPR_P (tem)
2192 || TREE_CODE (tem) == VIEW_CONVERT_EXPR)
2193 && (tem = fold_unary_ignore_overflow (TREE_CODE (val),
2194 TREE_TYPE (val), tem)))
2198 if (!is_gimple_min_invariant (val)
2199 && TREE_CODE (val) != SSA_NAME)
2200 result = vn_nary_op_lookup (val, NULL);
2201 /* If the expression is not yet available, value-number lhs to
2202 a new SSA_NAME we create. */
2205 result = make_ssa_name (SSA_NAME_VAR (lhs), gimple_build_nop ());
2206 /* Initialize value-number information properly. */
2207 VN_INFO_GET (result)->valnum = result;
2208 VN_INFO (result)->value_id = get_next_value_id ();
2209 VN_INFO (result)->expr = val;
2210 VN_INFO (result)->has_constants = expr_has_constants (val);
2211 VN_INFO (result)->needs_insertion = true;
2212 /* As all "inserted" statements are singleton SCCs, insert
2213 to the valid table. This is strictly needed to
2214 avoid re-generating new value SSA_NAMEs for the same
2215 expression during SCC iteration over and over (the
2216 optimistic table gets cleared after each iteration).
2217 We do not need to insert into the optimistic table, as
2218 lookups there will fall back to the valid table. */
2219 if (current_info == optimistic_info)
2221 current_info = valid_info;
2222 vn_nary_op_insert (val, result);
2223 current_info = optimistic_info;
2226 vn_nary_op_insert (val, result);
2227 if (dump_file && (dump_flags & TDF_DETAILS))
2229 fprintf (dump_file, "Inserting name ");
2230 print_generic_expr (dump_file, result, 0);
2231 fprintf (dump_file, " for expression ");
2232 print_generic_expr (dump_file, val, 0);
2233 fprintf (dump_file, "\n");
2240 changed = set_ssa_val_to (lhs, result);
2241 if (TREE_CODE (result) == SSA_NAME
2242 && VN_INFO (result)->has_constants)
2244 VN_INFO (lhs)->expr = VN_INFO (result)->expr;
2245 VN_INFO (lhs)->has_constants = true;
2250 changed = set_ssa_val_to (lhs, lhs);
2251 vn_reference_insert (op, lhs, last_vuse);
2258 /* Visit a store to a reference operator LHS, part of STMT, value number it,
2259 and return true if the value number of the LHS has changed as a result. */
2262 visit_reference_op_store (tree lhs, tree op, gimple stmt)
2264 bool changed = false;
2266 bool resultsame = false;
2268 /* First we want to lookup using the *vuses* from the store and see
2269 if there the last store to this location with the same address
2272 The vuses represent the memory state before the store. If the
2273 memory state, address, and value of the store is the same as the
2274 last store to this location, then this store will produce the
2275 same memory state as that store.
2277 In this case the vdef versions for this store are value numbered to those
2278 vuse versions, since they represent the same memory state after
2281 Otherwise, the vdefs for the store are used when inserting into
2282 the table, since the store generates a new memory state. */
2284 result = vn_reference_lookup (lhs, gimple_vuse (stmt), false, NULL);
2288 if (TREE_CODE (result) == SSA_NAME)
2289 result = SSA_VAL (result);
2290 if (TREE_CODE (op) == SSA_NAME)
2292 resultsame = expressions_equal_p (result, op);
2295 if (!result || !resultsame)
2299 if (dump_file && (dump_flags & TDF_DETAILS))
2301 fprintf (dump_file, "No store match\n");
2302 fprintf (dump_file, "Value numbering store ");
2303 print_generic_expr (dump_file, lhs, 0);
2304 fprintf (dump_file, " to ");
2305 print_generic_expr (dump_file, op, 0);
2306 fprintf (dump_file, "\n");
2308 /* Have to set value numbers before insert, since insert is
2309 going to valueize the references in-place. */
2310 if ((vdef = gimple_vdef (stmt)))
2312 VN_INFO (vdef)->use_processed = true;
2313 changed |= set_ssa_val_to (vdef, vdef);
2316 /* Do not insert structure copies into the tables. */
2317 if (is_gimple_min_invariant (op)
2318 || is_gimple_reg (op))
2319 vn_reference_insert (lhs, op, vdef);
2323 /* We had a match, so value number the vdef to have the value
2324 number of the vuse it came from. */
2327 if (dump_file && (dump_flags & TDF_DETAILS))
2328 fprintf (dump_file, "Store matched earlier value,"
2329 "value numbering store vdefs to matching vuses.\n");
2331 def = gimple_vdef (stmt);
2332 use = gimple_vuse (stmt);
2334 VN_INFO (def)->use_processed = true;
2335 changed |= set_ssa_val_to (def, SSA_VAL (use));
2341 /* Visit and value number PHI, return true if the value number
2345 visit_phi (gimple phi)
2347 bool changed = false;
2349 tree sameval = VN_TOP;
2350 bool allsame = true;
2353 /* TODO: We could check for this in init_sccvn, and replace this
2354 with a gcc_assert. */
2355 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
2356 return set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2358 /* See if all non-TOP arguments have the same value. TOP is
2359 equivalent to everything, so we can ignore it. */
2360 for (i = 0; i < gimple_phi_num_args (phi); i++)
2362 tree def = PHI_ARG_DEF (phi, i);
2364 if (TREE_CODE (def) == SSA_NAME)
2365 def = SSA_VAL (def);
2368 if (sameval == VN_TOP)
2374 if (!expressions_equal_p (def, sameval))
2382 /* If all value numbered to the same value, the phi node has that
2386 if (is_gimple_min_invariant (sameval))
2388 VN_INFO (PHI_RESULT (phi))->has_constants = true;
2389 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2393 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2394 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2397 if (TREE_CODE (sameval) == SSA_NAME)
2398 return visit_copy (PHI_RESULT (phi), sameval);
2400 return set_ssa_val_to (PHI_RESULT (phi), sameval);
2403 /* Otherwise, see if it is equivalent to a phi node in this block. */
2404 result = vn_phi_lookup (phi);
2407 if (TREE_CODE (result) == SSA_NAME)
2408 changed = visit_copy (PHI_RESULT (phi), result);
2410 changed = set_ssa_val_to (PHI_RESULT (phi), result);
2414 vn_phi_insert (phi, PHI_RESULT (phi));
2415 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2416 VN_INFO (PHI_RESULT (phi))->expr = PHI_RESULT (phi);
2417 changed = set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2423 /* Return true if EXPR contains constants. */
2426 expr_has_constants (tree expr)
2428 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2431 return is_gimple_min_invariant (TREE_OPERAND (expr, 0));
2434 return is_gimple_min_invariant (TREE_OPERAND (expr, 0))
2435 || is_gimple_min_invariant (TREE_OPERAND (expr, 1));
2436 /* Constants inside reference ops are rarely interesting, but
2437 it can take a lot of looking to find them. */
2439 case tcc_declaration:
2442 return is_gimple_min_invariant (expr);
2447 /* Return true if STMT contains constants. */
2450 stmt_has_constants (gimple stmt)
2452 if (gimple_code (stmt) != GIMPLE_ASSIGN)
2455 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2457 case GIMPLE_UNARY_RHS:
2458 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2460 case GIMPLE_BINARY_RHS:
2461 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2462 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt)));
2463 case GIMPLE_TERNARY_RHS:
2464 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2465 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))
2466 || is_gimple_min_invariant (gimple_assign_rhs3 (stmt)));
2467 case GIMPLE_SINGLE_RHS:
2468 /* Constants inside reference ops are rarely interesting, but
2469 it can take a lot of looking to find them. */
2470 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2477 /* Replace SSA_NAMES in expr with their value numbers, and return the
2479 This is performed in place. */
2482 valueize_expr (tree expr)
2484 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2487 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2488 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2489 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2492 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2493 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2494 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2495 if (TREE_CODE (TREE_OPERAND (expr, 1)) == SSA_NAME
2496 && SSA_VAL (TREE_OPERAND (expr, 1)) != VN_TOP)
2497 TREE_OPERAND (expr, 1) = SSA_VAL (TREE_OPERAND (expr, 1));
2505 /* Simplify the binary expression RHS, and return the result if
2509 simplify_binary_expression (gimple stmt)
2511 tree result = NULL_TREE;
2512 tree op0 = gimple_assign_rhs1 (stmt);
2513 tree op1 = gimple_assign_rhs2 (stmt);
2515 /* This will not catch every single case we could combine, but will
2516 catch those with constants. The goal here is to simultaneously
2517 combine constants between expressions, but avoid infinite
2518 expansion of expressions during simplification. */
2519 if (TREE_CODE (op0) == SSA_NAME)
2521 if (VN_INFO (op0)->has_constants
2522 || TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
2523 op0 = valueize_expr (vn_get_expr_for (op0));
2524 else if (SSA_VAL (op0) != VN_TOP && SSA_VAL (op0) != op0)
2525 op0 = SSA_VAL (op0);
2528 if (TREE_CODE (op1) == SSA_NAME)
2530 if (VN_INFO (op1)->has_constants)
2531 op1 = valueize_expr (vn_get_expr_for (op1));
2532 else if (SSA_VAL (op1) != VN_TOP && SSA_VAL (op1) != op1)
2533 op1 = SSA_VAL (op1);
2536 /* Avoid folding if nothing changed. */
2537 if (op0 == gimple_assign_rhs1 (stmt)
2538 && op1 == gimple_assign_rhs2 (stmt))
2541 fold_defer_overflow_warnings ();
2543 result = fold_binary (gimple_assign_rhs_code (stmt),
2544 gimple_expr_type (stmt), op0, op1);
2546 STRIP_USELESS_TYPE_CONVERSION (result);
2548 fold_undefer_overflow_warnings (result && valid_gimple_rhs_p (result),
2551 /* Make sure result is not a complex expression consisting
2552 of operators of operators (IE (a + b) + (a + c))
2553 Otherwise, we will end up with unbounded expressions if
2554 fold does anything at all. */
2555 if (result && valid_gimple_rhs_p (result))
2561 /* Simplify the unary expression RHS, and return the result if
2565 simplify_unary_expression (gimple stmt)
2567 tree result = NULL_TREE;
2568 tree orig_op0, op0 = gimple_assign_rhs1 (stmt);
2570 /* We handle some tcc_reference codes here that are all
2571 GIMPLE_ASSIGN_SINGLE codes. */
2572 if (gimple_assign_rhs_code (stmt) == REALPART_EXPR
2573 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2574 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2575 op0 = TREE_OPERAND (op0, 0);
2577 if (TREE_CODE (op0) != SSA_NAME)
2581 if (VN_INFO (op0)->has_constants)
2582 op0 = valueize_expr (vn_get_expr_for (op0));
2583 else if (gimple_assign_cast_p (stmt)
2584 || gimple_assign_rhs_code (stmt) == REALPART_EXPR
2585 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2586 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2588 /* We want to do tree-combining on conversion-like expressions.
2589 Make sure we feed only SSA_NAMEs or constants to fold though. */
2590 tree tem = valueize_expr (vn_get_expr_for (op0));
2591 if (UNARY_CLASS_P (tem)
2592 || BINARY_CLASS_P (tem)
2593 || TREE_CODE (tem) == VIEW_CONVERT_EXPR
2594 || TREE_CODE (tem) == SSA_NAME
2595 || is_gimple_min_invariant (tem))
2599 /* Avoid folding if nothing changed, but remember the expression. */
2600 if (op0 == orig_op0)
2603 result = fold_unary_ignore_overflow (gimple_assign_rhs_code (stmt),
2604 gimple_expr_type (stmt), op0);
2607 STRIP_USELESS_TYPE_CONVERSION (result);
2608 if (valid_gimple_rhs_p (result))
2615 /* Try to simplify RHS using equivalences and constant folding. */
2618 try_to_simplify (gimple stmt)
2622 /* For stores we can end up simplifying a SSA_NAME rhs. Just return
2623 in this case, there is no point in doing extra work. */
2624 if (gimple_assign_copy_p (stmt)
2625 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
2628 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2630 case tcc_declaration:
2631 tem = get_symbol_constant_value (gimple_assign_rhs1 (stmt));
2637 /* Do not do full-blown reference lookup here, but simplify
2638 reads from constant aggregates. */
2639 tem = fold_const_aggregate_ref (gimple_assign_rhs1 (stmt));
2643 /* Fallthrough for some codes that can operate on registers. */
2644 if (!(TREE_CODE (gimple_assign_rhs1 (stmt)) == REALPART_EXPR
2645 || TREE_CODE (gimple_assign_rhs1 (stmt)) == IMAGPART_EXPR
2646 || TREE_CODE (gimple_assign_rhs1 (stmt)) == VIEW_CONVERT_EXPR))
2648 /* We could do a little more with unary ops, if they expand
2649 into binary ops, but it's debatable whether it is worth it. */
2651 return simplify_unary_expression (stmt);
2653 case tcc_comparison:
2655 return simplify_binary_expression (stmt);
2664 /* Visit and value number USE, return true if the value number
2668 visit_use (tree use)
2670 bool changed = false;
2671 gimple stmt = SSA_NAME_DEF_STMT (use);
2673 VN_INFO (use)->use_processed = true;
2675 gcc_assert (!SSA_NAME_IN_FREE_LIST (use));
2676 if (dump_file && (dump_flags & TDF_DETAILS)
2677 && !SSA_NAME_IS_DEFAULT_DEF (use))
2679 fprintf (dump_file, "Value numbering ");
2680 print_generic_expr (dump_file, use, 0);
2681 fprintf (dump_file, " stmt = ");
2682 print_gimple_stmt (dump_file, stmt, 0, 0);
2685 /* Handle uninitialized uses. */
2686 if (SSA_NAME_IS_DEFAULT_DEF (use))
2687 changed = set_ssa_val_to (use, use);
2690 if (gimple_code (stmt) == GIMPLE_PHI)
2691 changed = visit_phi (stmt);
2692 else if (!gimple_has_lhs (stmt)
2693 || gimple_has_volatile_ops (stmt)
2694 || stmt_could_throw_p (stmt))
2695 changed = defs_to_varying (stmt);
2696 else if (is_gimple_assign (stmt))
2698 tree lhs = gimple_assign_lhs (stmt);
2701 /* Shortcut for copies. Simplifying copies is pointless,
2702 since we copy the expression and value they represent. */
2703 if (gimple_assign_copy_p (stmt)
2704 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2705 && TREE_CODE (lhs) == SSA_NAME)
2707 changed = visit_copy (lhs, gimple_assign_rhs1 (stmt));
2710 simplified = try_to_simplify (stmt);
2713 if (dump_file && (dump_flags & TDF_DETAILS))
2715 fprintf (dump_file, "RHS ");
2716 print_gimple_expr (dump_file, stmt, 0, 0);
2717 fprintf (dump_file, " simplified to ");
2718 print_generic_expr (dump_file, simplified, 0);
2719 if (TREE_CODE (lhs) == SSA_NAME)
2720 fprintf (dump_file, " has constants %d\n",
2721 expr_has_constants (simplified));
2723 fprintf (dump_file, "\n");
2726 /* Setting value numbers to constants will occasionally
2727 screw up phi congruence because constants are not
2728 uniquely associated with a single ssa name that can be
2731 && is_gimple_min_invariant (simplified)
2732 && TREE_CODE (lhs) == SSA_NAME)
2734 VN_INFO (lhs)->expr = simplified;
2735 VN_INFO (lhs)->has_constants = true;
2736 changed = set_ssa_val_to (lhs, simplified);
2740 && TREE_CODE (simplified) == SSA_NAME
2741 && TREE_CODE (lhs) == SSA_NAME)
2743 changed = visit_copy (lhs, simplified);
2746 else if (simplified)
2748 if (TREE_CODE (lhs) == SSA_NAME)
2750 VN_INFO (lhs)->has_constants = expr_has_constants (simplified);
2751 /* We have to unshare the expression or else
2752 valuizing may change the IL stream. */
2753 VN_INFO (lhs)->expr = unshare_expr (simplified);
2756 else if (stmt_has_constants (stmt)
2757 && TREE_CODE (lhs) == SSA_NAME)
2758 VN_INFO (lhs)->has_constants = true;
2759 else if (TREE_CODE (lhs) == SSA_NAME)
2761 /* We reset expr and constantness here because we may
2762 have been value numbering optimistically, and
2763 iterating. They may become non-constant in this case,
2764 even if they were optimistically constant. */
2766 VN_INFO (lhs)->has_constants = false;
2767 VN_INFO (lhs)->expr = NULL_TREE;
2770 if ((TREE_CODE (lhs) == SSA_NAME
2771 /* We can substitute SSA_NAMEs that are live over
2772 abnormal edges with their constant value. */
2773 && !(gimple_assign_copy_p (stmt)
2774 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2776 && is_gimple_min_invariant (simplified))
2777 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2778 /* Stores or copies from SSA_NAMEs that are live over
2779 abnormal edges are a problem. */
2780 || (gimple_assign_single_p (stmt)
2781 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2782 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt))))
2783 changed = defs_to_varying (stmt);
2784 else if (REFERENCE_CLASS_P (lhs) || DECL_P (lhs))
2786 changed = visit_reference_op_store (lhs, gimple_assign_rhs1 (stmt), stmt);
2788 else if (TREE_CODE (lhs) == SSA_NAME)
2790 if ((gimple_assign_copy_p (stmt)
2791 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2793 && is_gimple_min_invariant (simplified)))
2795 VN_INFO (lhs)->has_constants = true;
2797 changed = set_ssa_val_to (lhs, simplified);
2799 changed = set_ssa_val_to (lhs, gimple_assign_rhs1 (stmt));
2803 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2805 case GIMPLE_UNARY_RHS:
2806 changed = visit_unary_op (lhs, stmt);
2808 case GIMPLE_BINARY_RHS:
2809 changed = visit_binary_op (lhs, stmt);
2811 case GIMPLE_SINGLE_RHS:
2812 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2815 /* VOP-less references can go through unary case. */
2816 if ((gimple_assign_rhs_code (stmt) == REALPART_EXPR
2817 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2818 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR )
2819 && TREE_CODE (TREE_OPERAND (gimple_assign_rhs1 (stmt), 0)) == SSA_NAME)
2821 changed = visit_unary_op (lhs, stmt);
2825 case tcc_declaration:
2826 changed = visit_reference_op_load
2827 (lhs, gimple_assign_rhs1 (stmt), stmt);
2829 case tcc_expression:
2830 if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
2832 changed = visit_unary_op (lhs, stmt);
2837 changed = defs_to_varying (stmt);
2841 changed = defs_to_varying (stmt);
2847 changed = defs_to_varying (stmt);
2849 else if (is_gimple_call (stmt))
2851 tree lhs = gimple_call_lhs (stmt);
2853 /* ??? We could try to simplify calls. */
2855 if (stmt_has_constants (stmt)
2856 && TREE_CODE (lhs) == SSA_NAME)
2857 VN_INFO (lhs)->has_constants = true;
2858 else if (TREE_CODE (lhs) == SSA_NAME)
2860 /* We reset expr and constantness here because we may
2861 have been value numbering optimistically, and
2862 iterating. They may become non-constant in this case,
2863 even if they were optimistically constant. */
2864 VN_INFO (lhs)->has_constants = false;
2865 VN_INFO (lhs)->expr = NULL_TREE;
2868 if (TREE_CODE (lhs) == SSA_NAME
2869 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2870 changed = defs_to_varying (stmt);
2871 /* ??? We should handle stores from calls. */
2872 else if (TREE_CODE (lhs) == SSA_NAME)
2874 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2875 changed = visit_reference_op_call (lhs, stmt);
2877 changed = defs_to_varying (stmt);
2880 changed = defs_to_varying (stmt);
2887 /* Compare two operands by reverse postorder index */
2890 compare_ops (const void *pa, const void *pb)
2892 const tree opa = *((const tree *)pa);
2893 const tree opb = *((const tree *)pb);
2894 gimple opstmta = SSA_NAME_DEF_STMT (opa);
2895 gimple opstmtb = SSA_NAME_DEF_STMT (opb);
2899 if (gimple_nop_p (opstmta) && gimple_nop_p (opstmtb))
2900 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2901 else if (gimple_nop_p (opstmta))
2903 else if (gimple_nop_p (opstmtb))
2906 bba = gimple_bb (opstmta);
2907 bbb = gimple_bb (opstmtb);
2910 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2918 if (gimple_code (opstmta) == GIMPLE_PHI
2919 && gimple_code (opstmtb) == GIMPLE_PHI)
2920 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2921 else if (gimple_code (opstmta) == GIMPLE_PHI)
2923 else if (gimple_code (opstmtb) == GIMPLE_PHI)
2925 else if (gimple_uid (opstmta) != gimple_uid (opstmtb))
2926 return gimple_uid (opstmta) - gimple_uid (opstmtb);
2928 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2930 return rpo_numbers[bba->index] - rpo_numbers[bbb->index];
2933 /* Sort an array containing members of a strongly connected component
2934 SCC so that the members are ordered by RPO number.
2935 This means that when the sort is complete, iterating through the
2936 array will give you the members in RPO order. */
2939 sort_scc (VEC (tree, heap) *scc)
2941 qsort (VEC_address (tree, scc),
2942 VEC_length (tree, scc),
2947 /* Insert the no longer used nary ONARY to the hash INFO. */
2950 copy_nary (vn_nary_op_t onary, vn_tables_t info)
2952 size_t size = (sizeof (struct vn_nary_op_s)
2953 - sizeof (tree) * (4 - onary->length));
2954 vn_nary_op_t nary = (vn_nary_op_t) obstack_alloc (&info->nary_obstack, size);
2956 memcpy (nary, onary, size);
2957 slot = htab_find_slot_with_hash (info->nary, nary, nary->hashcode, INSERT);
2958 gcc_assert (!*slot);
2962 /* Insert the no longer used phi OPHI to the hash INFO. */
2965 copy_phi (vn_phi_t ophi, vn_tables_t info)
2967 vn_phi_t phi = (vn_phi_t) pool_alloc (info->phis_pool);
2969 memcpy (phi, ophi, sizeof (*phi));
2970 ophi->phiargs = NULL;
2971 slot = htab_find_slot_with_hash (info->phis, phi, phi->hashcode, INSERT);
2972 gcc_assert (!*slot);
2976 /* Insert the no longer used reference OREF to the hash INFO. */
2979 copy_reference (vn_reference_t oref, vn_tables_t info)
2983 ref = (vn_reference_t) pool_alloc (info->references_pool);
2984 memcpy (ref, oref, sizeof (*ref));
2985 oref->operands = NULL;
2986 slot = htab_find_slot_with_hash (info->references, ref, ref->hashcode,
2989 free_reference (*slot);
2993 /* Process a strongly connected component in the SSA graph. */
2996 process_scc (VEC (tree, heap) *scc)
3000 unsigned int iterations = 0;
3001 bool changed = true;
3007 /* If the SCC has a single member, just visit it. */
3008 if (VEC_length (tree, scc) == 1)
3010 tree use = VEC_index (tree, scc, 0);
3011 if (!VN_INFO (use)->use_processed)
3016 /* Iterate over the SCC with the optimistic table until it stops
3018 current_info = optimistic_info;
3023 /* As we are value-numbering optimistically we have to
3024 clear the expression tables and the simplified expressions
3025 in each iteration until we converge. */
3026 htab_empty (optimistic_info->nary);
3027 htab_empty (optimistic_info->phis);
3028 htab_empty (optimistic_info->references);
3029 obstack_free (&optimistic_info->nary_obstack, NULL);
3030 gcc_obstack_init (&optimistic_info->nary_obstack);
3031 empty_alloc_pool (optimistic_info->phis_pool);
3032 empty_alloc_pool (optimistic_info->references_pool);
3033 for (i = 0; VEC_iterate (tree, scc, i, var); i++)
3034 VN_INFO (var)->expr = NULL_TREE;
3035 for (i = 0; VEC_iterate (tree, scc, i, var); i++)
3036 changed |= visit_use (var);
3039 statistics_histogram_event (cfun, "SCC iterations", iterations);
3041 /* Finally, copy the contents of the no longer used optimistic
3042 table to the valid table. */
3043 FOR_EACH_HTAB_ELEMENT (optimistic_info->nary, nary, vn_nary_op_t, hi)
3044 copy_nary (nary, valid_info);
3045 FOR_EACH_HTAB_ELEMENT (optimistic_info->phis, phi, vn_phi_t, hi)
3046 copy_phi (phi, valid_info);
3047 FOR_EACH_HTAB_ELEMENT (optimistic_info->references, ref, vn_reference_t, hi)
3048 copy_reference (ref, valid_info);
3050 current_info = valid_info;
3053 DEF_VEC_O(ssa_op_iter);
3054 DEF_VEC_ALLOC_O(ssa_op_iter,heap);
3056 /* Pop the components of the found SCC for NAME off the SCC stack
3057 and process them. Returns true if all went well, false if
3058 we run into resource limits. */
3061 extract_and_process_scc_for_name (tree name)
3063 VEC (tree, heap) *scc = NULL;
3066 /* Found an SCC, pop the components off the SCC stack and
3070 x = VEC_pop (tree, sccstack);
3072 VN_INFO (x)->on_sccstack = false;
3073 VEC_safe_push (tree, heap, scc, x);
3074 } while (x != name);
3076 /* Bail out of SCCVN in case a SCC turns out to be incredibly large. */
3077 if (VEC_length (tree, scc)
3078 > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE))
3081 fprintf (dump_file, "WARNING: Giving up with SCCVN due to "
3082 "SCC size %u exceeding %u\n", VEC_length (tree, scc),
3083 (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE));
3087 if (VEC_length (tree, scc) > 1)
3090 if (dump_file && (dump_flags & TDF_DETAILS))
3091 print_scc (dump_file, scc);
3095 VEC_free (tree, heap, scc);
3100 /* Depth first search on NAME to discover and process SCC's in the SSA
3102 Execution of this algorithm relies on the fact that the SCC's are
3103 popped off the stack in topological order.
3104 Returns true if successful, false if we stopped processing SCC's due
3105 to resource constraints. */
3110 VEC(ssa_op_iter, heap) *itervec = NULL;
3111 VEC(tree, heap) *namevec = NULL;
3112 use_operand_p usep = NULL;
3119 VN_INFO (name)->dfsnum = next_dfs_num++;
3120 VN_INFO (name)->visited = true;
3121 VN_INFO (name)->low = VN_INFO (name)->dfsnum;
3123 VEC_safe_push (tree, heap, sccstack, name);
3124 VN_INFO (name)->on_sccstack = true;
3125 defstmt = SSA_NAME_DEF_STMT (name);
3127 /* Recursively DFS on our operands, looking for SCC's. */
3128 if (!gimple_nop_p (defstmt))
3130 /* Push a new iterator. */
3131 if (gimple_code (defstmt) == GIMPLE_PHI)
3132 usep = op_iter_init_phiuse (&iter, defstmt, SSA_OP_ALL_USES);
3134 usep = op_iter_init_use (&iter, defstmt, SSA_OP_ALL_USES);
3137 clear_and_done_ssa_iter (&iter);
3141 /* If we are done processing uses of a name, go up the stack
3142 of iterators and process SCCs as we found them. */
3143 if (op_iter_done (&iter))
3145 /* See if we found an SCC. */
3146 if (VN_INFO (name)->low == VN_INFO (name)->dfsnum)
3147 if (!extract_and_process_scc_for_name (name))
3149 VEC_free (tree, heap, namevec);
3150 VEC_free (ssa_op_iter, heap, itervec);
3154 /* Check if we are done. */
3155 if (VEC_empty (tree, namevec))
3157 VEC_free (tree, heap, namevec);
3158 VEC_free (ssa_op_iter, heap, itervec);
3162 /* Restore the last use walker and continue walking there. */
3164 name = VEC_pop (tree, namevec);
3165 memcpy (&iter, VEC_last (ssa_op_iter, itervec),
3166 sizeof (ssa_op_iter));
3167 VEC_pop (ssa_op_iter, itervec);
3168 goto continue_walking;
3171 use = USE_FROM_PTR (usep);
3173 /* Since we handle phi nodes, we will sometimes get
3174 invariants in the use expression. */
3175 if (TREE_CODE (use) == SSA_NAME)
3177 if (! (VN_INFO (use)->visited))
3179 /* Recurse by pushing the current use walking state on
3180 the stack and starting over. */
3181 VEC_safe_push(ssa_op_iter, heap, itervec, &iter);
3182 VEC_safe_push(tree, heap, namevec, name);
3187 VN_INFO (name)->low = MIN (VN_INFO (name)->low,
3188 VN_INFO (use)->low);
3190 if (VN_INFO (use)->dfsnum < VN_INFO (name)->dfsnum
3191 && VN_INFO (use)->on_sccstack)
3193 VN_INFO (name)->low = MIN (VN_INFO (use)->dfsnum,
3194 VN_INFO (name)->low);
3198 usep = op_iter_next_use (&iter);
3202 /* Allocate a value number table. */
3205 allocate_vn_table (vn_tables_t table)
3207 table->phis = htab_create (23, vn_phi_hash, vn_phi_eq, free_phi);
3208 table->nary = htab_create (23, vn_nary_op_hash, vn_nary_op_eq, NULL);
3209 table->references = htab_create (23, vn_reference_hash, vn_reference_eq,
3212 gcc_obstack_init (&table->nary_obstack);
3213 table->phis_pool = create_alloc_pool ("VN phis",
3214 sizeof (struct vn_phi_s),
3216 table->references_pool = create_alloc_pool ("VN references",
3217 sizeof (struct vn_reference_s),
3221 /* Free a value number table. */
3224 free_vn_table (vn_tables_t table)
3226 htab_delete (table->phis);
3227 htab_delete (table->nary);
3228 htab_delete (table->references);
3229 obstack_free (&table->nary_obstack, NULL);
3230 free_alloc_pool (table->phis_pool);
3231 free_alloc_pool (table->references_pool);
3239 int *rpo_numbers_temp;
3241 calculate_dominance_info (CDI_DOMINATORS);
3243 constant_to_value_id = htab_create (23, vn_constant_hash, vn_constant_eq,
3246 constant_value_ids = BITMAP_ALLOC (NULL);
3251 vn_ssa_aux_table = VEC_alloc (vn_ssa_aux_t, heap, num_ssa_names + 1);
3252 /* VEC_alloc doesn't actually grow it to the right size, it just
3253 preallocates the space to do so. */
3254 VEC_safe_grow_cleared (vn_ssa_aux_t, heap, vn_ssa_aux_table, num_ssa_names + 1);
3255 gcc_obstack_init (&vn_ssa_aux_obstack);
3257 shared_lookup_phiargs = NULL;
3258 shared_lookup_references = NULL;
3259 rpo_numbers = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3260 rpo_numbers_temp = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3261 pre_and_rev_post_order_compute (NULL, rpo_numbers_temp, false);
3263 /* RPO numbers is an array of rpo ordering, rpo[i] = bb means that
3264 the i'th block in RPO order is bb. We want to map bb's to RPO
3265 numbers, so we need to rearrange this array. */
3266 for (j = 0; j < n_basic_blocks - NUM_FIXED_BLOCKS; j++)
3267 rpo_numbers[rpo_numbers_temp[j]] = j;
3269 XDELETE (rpo_numbers_temp);
3271 VN_TOP = create_tmp_var_raw (void_type_node, "vn_top");
3273 /* Create the VN_INFO structures, and initialize value numbers to
3275 for (i = 0; i < num_ssa_names; i++)
3277 tree name = ssa_name (i);
3280 VN_INFO_GET (name)->valnum = VN_TOP;
3281 VN_INFO (name)->expr = NULL_TREE;
3282 VN_INFO (name)->value_id = 0;
3286 renumber_gimple_stmt_uids ();
3288 /* Create the valid and optimistic value numbering tables. */
3289 valid_info = XCNEW (struct vn_tables_s);
3290 allocate_vn_table (valid_info);
3291 optimistic_info = XCNEW (struct vn_tables_s);
3292 allocate_vn_table (optimistic_info);
3300 htab_delete (constant_to_value_id);
3301 BITMAP_FREE (constant_value_ids);
3302 VEC_free (tree, heap, shared_lookup_phiargs);
3303 VEC_free (vn_reference_op_s, heap, shared_lookup_references);
3304 XDELETEVEC (rpo_numbers);
3306 for (i = 0; i < num_ssa_names; i++)
3308 tree name = ssa_name (i);
3310 && VN_INFO (name)->needs_insertion)
3311 release_ssa_name (name);
3313 obstack_free (&vn_ssa_aux_obstack, NULL);
3314 VEC_free (vn_ssa_aux_t, heap, vn_ssa_aux_table);
3316 VEC_free (tree, heap, sccstack);
3317 free_vn_table (valid_info);
3318 XDELETE (valid_info);
3319 free_vn_table (optimistic_info);
3320 XDELETE (optimistic_info);
3323 /* Set the value ids in the valid hash tables. */
3326 set_hashtable_value_ids (void)
3333 /* Now set the value ids of the things we had put in the hash
3336 FOR_EACH_HTAB_ELEMENT (valid_info->nary,
3337 vno, vn_nary_op_t, hi)
3341 if (TREE_CODE (vno->result) == SSA_NAME)
3342 vno->value_id = VN_INFO (vno->result)->value_id;
3343 else if (is_gimple_min_invariant (vno->result))
3344 vno->value_id = get_or_alloc_constant_value_id (vno->result);
3348 FOR_EACH_HTAB_ELEMENT (valid_info->phis,
3353 if (TREE_CODE (vp->result) == SSA_NAME)
3354 vp->value_id = VN_INFO (vp->result)->value_id;
3355 else if (is_gimple_min_invariant (vp->result))
3356 vp->value_id = get_or_alloc_constant_value_id (vp->result);
3360 FOR_EACH_HTAB_ELEMENT (valid_info->references,
3361 vr, vn_reference_t, hi)
3365 if (TREE_CODE (vr->result) == SSA_NAME)
3366 vr->value_id = VN_INFO (vr->result)->value_id;
3367 else if (is_gimple_min_invariant (vr->result))
3368 vr->value_id = get_or_alloc_constant_value_id (vr->result);
3373 /* Do SCCVN. Returns true if it finished, false if we bailed out
3374 due to resource constraints. */
3381 bool changed = true;
3384 current_info = valid_info;
3386 for (param = DECL_ARGUMENTS (current_function_decl);
3388 param = TREE_CHAIN (param))
3390 if (gimple_default_def (cfun, param) != NULL)
3392 tree def = gimple_default_def (cfun, param);
3393 VN_INFO (def)->valnum = def;
3397 for (i = 1; i < num_ssa_names; ++i)
3399 tree name = ssa_name (i);
3401 && VN_INFO (name)->visited == false
3402 && !has_zero_uses (name))
3410 /* Initialize the value ids. */
3412 for (i = 1; i < num_ssa_names; ++i)
3414 tree name = ssa_name (i);
3418 info = VN_INFO (name);
3419 if (info->valnum == name
3420 || info->valnum == VN_TOP)
3421 info->value_id = get_next_value_id ();
3422 else if (is_gimple_min_invariant (info->valnum))
3423 info->value_id = get_or_alloc_constant_value_id (info->valnum);
3426 /* Propagate until they stop changing. */
3430 for (i = 1; i < num_ssa_names; ++i)
3432 tree name = ssa_name (i);
3436 info = VN_INFO (name);
3437 if (TREE_CODE (info->valnum) == SSA_NAME
3438 && info->valnum != name
3439 && info->value_id != VN_INFO (info->valnum)->value_id)
3442 info->value_id = VN_INFO (info->valnum)->value_id;
3447 set_hashtable_value_ids ();
3449 if (dump_file && (dump_flags & TDF_DETAILS))
3451 fprintf (dump_file, "Value numbers:\n");
3452 for (i = 0; i < num_ssa_names; i++)
3454 tree name = ssa_name (i);
3456 && VN_INFO (name)->visited
3457 && SSA_VAL (name) != name)
3459 print_generic_expr (dump_file, name, 0);
3460 fprintf (dump_file, " = ");
3461 print_generic_expr (dump_file, SSA_VAL (name), 0);
3462 fprintf (dump_file, "\n");
3470 /* Return the maximum value id we have ever seen. */
3473 get_max_value_id (void)
3475 return next_value_id;
3478 /* Return the next unique value id. */
3481 get_next_value_id (void)
3483 return next_value_id++;
3487 /* Compare two expressions E1 and E2 and return true if they are equal. */
3490 expressions_equal_p (tree e1, tree e2)
3492 /* The obvious case. */
3496 /* If only one of them is null, they cannot be equal. */
3500 /* Now perform the actual comparison. */
3501 if (TREE_CODE (e1) == TREE_CODE (e2)
3502 && operand_equal_p (e1, e2, OEP_PURE_SAME))
3509 /* Return true if the nary operation NARY may trap. This is a copy
3510 of stmt_could_throw_1_p adjusted to the SCCVN IL. */
3513 vn_nary_may_trap (vn_nary_op_t nary)
3516 tree rhs2 = NULL_TREE;
3517 bool honor_nans = false;
3518 bool honor_snans = false;
3519 bool fp_operation = false;
3520 bool honor_trapv = false;
3524 if (TREE_CODE_CLASS (nary->opcode) == tcc_comparison
3525 || TREE_CODE_CLASS (nary->opcode) == tcc_unary
3526 || TREE_CODE_CLASS (nary->opcode) == tcc_binary)
3529 fp_operation = FLOAT_TYPE_P (type);
3532 honor_nans = flag_trapping_math && !flag_finite_math_only;
3533 honor_snans = flag_signaling_nans != 0;
3535 else if (INTEGRAL_TYPE_P (type)
3536 && TYPE_OVERFLOW_TRAPS (type))
3539 if (nary->length >= 2)
3541 ret = operation_could_trap_helper_p (nary->opcode, fp_operation,
3543 honor_nans, honor_snans, rhs2,
3549 for (i = 0; i < nary->length; ++i)
3550 if (tree_could_trap_p (nary->op[i]))