1 /* Tree SCC value numbering
2 Copyright (C) 2007 Free Software Foundation, Inc.
3 Contributed by Daniel Berlin <dberlin@dberlin.org>
5 This file is part of GCC.
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.
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.
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/>. */
21 #ifndef TREE_SSA_SCCVN_H
22 #define TREE_SSA_SCCVN_H
24 /* TOP of the VN lattice. */
27 /* N-ary operations in the hashtable consist of length operands, an
28 opcode, and a type. Result is the value number of the operation,
29 and hashcode is stored to avoid having to calculate it
32 typedef struct vn_nary_op_s
34 /* Unique identify that all expressions with the same value have. */
35 unsigned int value_id;
36 ENUM_BITFIELD(tree_code) opcode : 16;
43 typedef const struct vn_nary_op_s *const_vn_nary_op_t;
45 /* Phi nodes in the hashtable consist of their non-VN_TOP phi
46 arguments, and the basic block the phi is in. Result is the value
47 number of the operation, and hashcode is stored to avoid having to
48 calculate it repeatedly. Phi nodes not in the same block are never
49 considered equivalent. */
51 typedef struct vn_phi_s
53 /* Unique identifier that all expressions with the same value have. */
54 unsigned int value_id;
56 VEC (tree, heap) *phiargs;
60 typedef const struct vn_phi_s *const_vn_phi_t;
62 /* Reference operands only exist in reference operations structures.
63 They consist of an opcode, type, and some number of operands. For
64 a given opcode, some, all, or none of the operands may be used.
65 The operands are there to store the information that makes up the
66 portion of the addressing calculation that opcode performs. */
68 typedef struct vn_reference_op_struct
70 enum tree_code opcode;
76 typedef vn_reference_op_s *vn_reference_op_t;
77 typedef const vn_reference_op_s *const_vn_reference_op_t;
79 DEF_VEC_O(vn_reference_op_s);
80 DEF_VEC_ALLOC_O(vn_reference_op_s, heap);
82 /* A reference operation in the hashtable is representation as a
83 collection of vuses, representing the memory state at the time of
84 the operation, and a collection of operands that make up the
85 addressing calculation. If two vn_reference_t's have the same set
86 of operands, they access the same memory location. We also store
87 the resulting value number, and the hashcode. The vuses are
88 always stored in order sorted by ssa name version. */
90 typedef struct vn_reference_s
92 /* Unique identifier that all expressions with the same value have. */
93 unsigned int value_id;
95 VEC (tree, gc) *vuses;
96 VEC (vn_reference_op_s, heap) *operands;
99 typedef const struct vn_reference_s *const_vn_reference_t;
101 typedef struct vn_constant_s
103 unsigned int value_id;
108 typedef struct vn_ssa_aux
110 /* Value number. This may be an SSA name or a constant. */
112 /* Representative expression, if not a direct constant. */
115 /* Unique identifier that all expressions with the same value have. */
116 unsigned int value_id;
118 /* SCC information. */
121 unsigned visited : 1;
122 unsigned on_sccstack : 1;
124 /* Whether the representative expression contains constants. */
125 unsigned has_constants : 1;
126 /* Whether the SSA_NAME has been value numbered already. This is
127 only saying whether visit_use has been called on it at least
128 once. It cannot be used to avoid visitation for SSA_NAME's
129 involved in non-singleton SCC's. */
130 unsigned use_processed : 1;
132 /* Whether the SSA_NAME has no defining statement and thus an
133 insertion of such with EXPR as definition is required before
134 a use can be created of it. */
135 unsigned needs_insertion : 1;
138 /* Return the value numbering info for an SSA_NAME. */
139 extern vn_ssa_aux_t VN_INFO (tree);
140 extern vn_ssa_aux_t VN_INFO_GET (tree);
141 bool run_scc_vn (bool);
142 void free_scc_vn (void);
143 void switch_to_PRE_table (void);
144 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
145 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
146 tree, tree, tree, tree, tree,
148 vn_nary_op_t vn_nary_op_insert (tree, tree);
149 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
150 tree, tree, tree, tree,
151 tree, tree, unsigned int);
152 tree vn_reference_lookup_pieces (VEC (tree, gc) *,
153 VEC (vn_reference_op_s, heap) *,
155 tree vn_reference_lookup (tree, VEC (tree, gc) *, bool, vn_reference_t *);
156 vn_reference_t vn_reference_insert (tree, tree, VEC (tree, gc) *);
157 vn_reference_t vn_reference_insert_pieces (VEC (tree, gc) *,
158 VEC (vn_reference_op_s, heap) *,
161 hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
162 int vn_nary_op_eq (const void *, const void *);
163 hashval_t vn_reference_compute_hash (const vn_reference_t);
164 int vn_reference_eq (const void *, const void *);
165 unsigned int get_max_value_id (void);
166 unsigned int get_next_value_id (void);
167 unsigned int get_or_alloc_constant_value_id (tree);
168 bool value_id_constant_p (unsigned int);
169 VEC (tree, gc) *shared_vuses_from_stmt (tree);
170 VEC (tree, gc) *copy_vuses_from_stmt (tree);
171 #endif /* TREE_SSA_SCCVN_H */