tree-ssa-sccvn.h revision 1.1.1.1.8.2 
1/* Tree SCC value numbering
2   Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
3   Contributed by Daniel Berlin <dberlin@dberlin.org>
4
5   This file is part of GCC.
6
7   GCC is free software; you can redistribute it and/or modify
8   under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 3 of the License, or
10   (at your option) any later version.
11
12   GCC is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with GCC; see the file COPYING3.  If not see
19   <http://www.gnu.org/licenses/>.  */
20
21#ifndef TREE_SSA_SCCVN_H
22#define TREE_SSA_SCCVN_H
23
24/* In tree-ssa-sccvn.c  */
25bool expressions_equal_p (tree, tree);
26
27
28/* TOP of the VN lattice.  */
29extern tree VN_TOP;
30
31/* N-ary operations in the hashtable consist of length operands, an
32   opcode, and a type.  Result is the value number of the operation,
33   and hashcode is stored to avoid having to calculate it
34   repeatedly.  */
35
36typedef struct vn_nary_op_s
37{
38  /* Unique identify that all expressions with the same value have. */
39  unsigned int value_id;
40  ENUM_BITFIELD(tree_code) opcode : 16;
41  unsigned length : 16;
42  hashval_t hashcode;
43  tree result;
44  tree type;
45  tree op[4];
46} *vn_nary_op_t;
47typedef const struct vn_nary_op_s *const_vn_nary_op_t;
48
49/* Phi nodes in the hashtable consist of their non-VN_TOP phi
50   arguments, and the basic block the phi is in. Result is the value
51   number of the operation, and hashcode is stored to avoid having to
52   calculate it repeatedly.  Phi nodes not in the same block are never
53   considered equivalent.  */
54
55typedef struct vn_phi_s
56{
57  /* Unique identifier that all expressions with the same value have. */
58  unsigned int value_id;
59  hashval_t hashcode;
60  VEC (tree, heap) *phiargs;
61  basic_block block;
62  tree result;
63} *vn_phi_t;
64typedef const struct vn_phi_s *const_vn_phi_t;
65
66/* Reference operands only exist in reference operations structures.
67   They consist of an opcode, type, and some number of operands.  For
68   a given opcode, some, all, or none of the operands may be used.
69   The operands are there to store the information that makes up the
70   portion of the addressing calculation that opcode performs.  */
71
72typedef struct vn_reference_op_struct
73{
74  enum tree_code opcode;
75  tree type;
76  tree op0;
77  tree op1;
78  tree op2;
79} vn_reference_op_s;
80typedef vn_reference_op_s *vn_reference_op_t;
81typedef const vn_reference_op_s *const_vn_reference_op_t;
82
83DEF_VEC_O(vn_reference_op_s);
84DEF_VEC_ALLOC_O(vn_reference_op_s, heap);
85
86/* A reference operation in the hashtable is representation as
87   the vuse, representing the memory state at the time of
88   the operation, and a collection of operands that make up the
89   addressing calculation.  If two vn_reference_t's have the same set
90   of operands, they access the same memory location. We also store
91   the resulting value number, and the hashcode.  */
92
93typedef struct vn_reference_s
94{
95  /* Unique identifier that all expressions with the same value have. */
96  unsigned int value_id;
97  hashval_t hashcode;
98  tree vuse;
99  alias_set_type set;
100  tree type;
101  VEC (vn_reference_op_s, heap) *operands;
102  tree result;
103} *vn_reference_t;
104typedef const struct vn_reference_s *const_vn_reference_t;
105
106typedef struct vn_constant_s
107{
108  unsigned int value_id;
109  hashval_t hashcode;
110  tree constant;
111} *vn_constant_t;
112
113/* Hash the constant CONSTANT with distinguishing type incompatible
114   constants in the types_compatible_p sense.  */
115
116static inline hashval_t
117vn_hash_constant_with_type (tree constant)
118{
119  tree type = TREE_TYPE (constant);
120  return (iterative_hash_expr (constant, 0)
121	  + INTEGRAL_TYPE_P (type)
122	  + (INTEGRAL_TYPE_P (type)
123	     ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
124}
125
126/* Compare the constants C1 and C2 with distinguishing type incompatible
127   constants in the types_compatible_p sense.  */
128
129static inline bool
130vn_constant_eq_with_type (tree c1, tree c2)
131{
132  return (expressions_equal_p (c1, c2)
133	  && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
134}
135
136typedef struct vn_ssa_aux
137{
138  /* Value number. This may be an SSA name or a constant.  */
139  tree valnum;
140  /* Representative expression, if not a direct constant. */
141  tree expr;
142
143  /* Unique identifier that all expressions with the same value have. */
144  unsigned int value_id;
145
146  /* SCC information.  */
147  unsigned int dfsnum;
148  unsigned int low;
149  unsigned visited : 1;
150  unsigned on_sccstack : 1;
151
152  /* Whether the representative expression contains constants.  */
153  unsigned has_constants : 1;
154  /* Whether the SSA_NAME has been value numbered already.  This is
155     only saying whether visit_use has been called on it at least
156     once.  It cannot be used to avoid visitation for SSA_NAME's
157     involved in non-singleton SCC's.  */
158  unsigned use_processed : 1;
159
160  /* Whether the SSA_NAME has no defining statement and thus an
161     insertion of such with EXPR as definition is required before
162     a use can be created of it.  */
163  unsigned needs_insertion : 1;
164} *vn_ssa_aux_t;
165
166typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
167
168/* Return the value numbering info for an SSA_NAME.  */
169extern vn_ssa_aux_t VN_INFO (tree);
170extern vn_ssa_aux_t VN_INFO_GET (tree);
171tree vn_get_expr_for (tree);
172bool run_scc_vn (bool, vn_lookup_kind);
173void free_scc_vn (void);
174tree vn_nary_op_lookup (tree, vn_nary_op_t *);
175tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
176tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
177			       tree, tree, tree, tree, tree,
178			       vn_nary_op_t *);
179vn_nary_op_t vn_nary_op_insert (tree, tree);
180vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
181vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
182				       tree, tree, tree, tree,
183				       tree, tree, unsigned int);
184void vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **,
185				 unsigned int *);
186void copy_reference_ops_from_ref (tree, VEC(vn_reference_op_s, heap) **);
187void copy_reference_ops_from_call (gimple, VEC(vn_reference_op_s, heap) **);
188bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
189				    VEC (vn_reference_op_s, heap) *);
190tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
191				 VEC (vn_reference_op_s, heap) *,
192				 vn_reference_t *, vn_lookup_kind);
193tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
194vn_reference_t vn_reference_insert (tree, tree, tree);
195vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
196					   VEC (vn_reference_op_s, heap) *,
197					   tree, unsigned int);
198
199hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
200int vn_nary_op_eq (const void *, const void *);
201bool vn_nary_may_trap (vn_nary_op_t);
202hashval_t vn_reference_compute_hash (const vn_reference_t);
203int vn_reference_eq (const void *, const void *);
204unsigned int get_max_value_id (void);
205unsigned int get_next_value_id (void);
206unsigned int get_constant_value_id (tree);
207unsigned int get_or_alloc_constant_value_id (tree);
208bool value_id_constant_p (unsigned int);
209#endif /* TREE_SSA_SCCVN_H  */
210