1 /* Tree SCC value numbering
2 Copyright (C) 2007-2019 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 */
25 bool expressions_equal_p (tree, tree);
26
27
28 /* TOP of the VN lattice. */
29 extern tree VN_TOP;
30
31 /* A predicated value. */
32 struct vn_pval
33 {
34 vn_pval *next;
35 /* The value of the expression this is attached to is RESULT in
36 case the expression is computed dominated by one of the blocks
37 in valid_dominated_by_p. */
38 tree result;
39 unsigned n;
40 int valid_dominated_by_p[1];
41 };
42
43 /* N-ary operations in the hashtable consist of length operands, an
44 opcode, and a type. Result is the value number of the operation,
45 and hashcode is stored to avoid having to calculate it
46 repeatedly. */
47
48 typedef struct vn_nary_op_s
49 {
50 vn_nary_op_s *next;
51 vn_nary_op_s *unwind_to;
52 /* Unique identify that all expressions with the same value have. */
53 unsigned int value_id;
54 ENUM_BITFIELD(tree_code) opcode : 16;
55 unsigned length : 16;
56 hashval_t hashcode;
57 unsigned predicated_values : 1;
58 union {
59 /* If ! predicated_values this is the value of the expression. */
60 tree result;
61 /* If predicated_values this is a list of values of the expression. */
62 vn_pval *values;
63 } u;
64 tree type;
65 tree op[1];
66 } *vn_nary_op_t;
67 typedef const struct vn_nary_op_s *const_vn_nary_op_t;
68
69 /* Return the size of a vn_nary_op_t with LENGTH operands. */
70
71 static inline size_t
sizeof_vn_nary_op(unsigned int length)72 sizeof_vn_nary_op (unsigned int length)
73 {
74 return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
75 }
76
77 /* Phi nodes in the hashtable consist of their non-VN_TOP phi
78 arguments, and the basic block the phi is in. Result is the value
79 number of the operation, and hashcode is stored to avoid having to
80 calculate it repeatedly. Phi nodes not in the same block are never
81 considered equivalent. */
82
83 typedef struct vn_phi_s
84 {
85 vn_phi_s *next;
86 /* Unique identifier that all expressions with the same value have. */
87 unsigned int value_id;
88 hashval_t hashcode;
89 basic_block block;
90 /* Controlling condition lhs/rhs. */
91 tree cclhs;
92 tree ccrhs;
93 tree type;
94 tree result;
95 /* The number of args is determined by EDGE_COUT (block->preds). */
96 tree phiargs[1];
97 } *vn_phi_t;
98 typedef const struct vn_phi_s *const_vn_phi_t;
99
100 /* Reference operands only exist in reference operations structures.
101 They consist of an opcode, type, and some number of operands. For
102 a given opcode, some, all, or none of the operands may be used.
103 The operands are there to store the information that makes up the
104 portion of the addressing calculation that opcode performs. */
105
106 typedef struct vn_reference_op_struct
107 {
108 ENUM_BITFIELD(tree_code) opcode : 16;
109 /* Dependence info, used for [TARGET_]MEM_REF only. */
110 unsigned short clique;
111 unsigned short base;
112 unsigned reverse : 1;
113 /* For storing TYPE_ALIGN for array ref element size computation. */
114 unsigned align : 6;
115 /* Constant offset this op adds or -1 if it is variable. */
116 poly_int64_pod off;
117 tree type;
118 tree op0;
119 tree op1;
120 tree op2;
121 } vn_reference_op_s;
122 typedef vn_reference_op_s *vn_reference_op_t;
123 typedef const vn_reference_op_s *const_vn_reference_op_t;
124
125 inline unsigned
vn_ref_op_align_unit(vn_reference_op_t op)126 vn_ref_op_align_unit (vn_reference_op_t op)
127 {
128 return op->align ? ((unsigned)1 << (op->align - 1)) / BITS_PER_UNIT : 0;
129 }
130
131 /* A reference operation in the hashtable is representation as
132 the vuse, representing the memory state at the time of
133 the operation, and a collection of operands that make up the
134 addressing calculation. If two vn_reference_t's have the same set
135 of operands, they access the same memory location. We also store
136 the resulting value number, and the hashcode. */
137
138 typedef struct vn_reference_s
139 {
140 vn_reference_s *next;
141 /* Unique identifier that all expressions with the same value have. */
142 unsigned int value_id;
143 hashval_t hashcode;
144 tree vuse;
145 alias_set_type set;
146 tree type;
147 vec<vn_reference_op_s> operands;
148 tree result;
149 tree result_vdef;
150 } *vn_reference_t;
151 typedef const struct vn_reference_s *const_vn_reference_t;
152
153 typedef struct vn_constant_s
154 {
155 unsigned int value_id;
156 hashval_t hashcode;
157 tree constant;
158 } *vn_constant_t;
159
160 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
161 enum vn_kind vn_get_stmt_kind (gimple *);
162
163 /* Hash the type TYPE using bits that distinguishes it in the
164 types_compatible_p sense. */
165
166 static inline hashval_t
vn_hash_type(tree type)167 vn_hash_type (tree type)
168 {
169 return (INTEGRAL_TYPE_P (type)
170 + (INTEGRAL_TYPE_P (type)
171 ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
172 }
173
174 /* Hash the constant CONSTANT with distinguishing type incompatible
175 constants in the types_compatible_p sense. */
176
177 static inline hashval_t
vn_hash_constant_with_type(tree constant)178 vn_hash_constant_with_type (tree constant)
179 {
180 inchash::hash hstate;
181 inchash::add_expr (constant, hstate);
182 hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
183 return hstate.end ();
184 }
185
186 /* Compare the constants C1 and C2 with distinguishing type incompatible
187 constants in the types_compatible_p sense. */
188
189 static inline bool
vn_constant_eq_with_type(tree c1,tree c2)190 vn_constant_eq_with_type (tree c1, tree c2)
191 {
192 return (expressions_equal_p (c1, c2)
193 && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
194 }
195
196 typedef struct vn_ssa_aux
197 {
198 /* SSA name this vn_ssa_aux is associated with in the lattice. */
199 tree name;
200 /* Value number. This may be an SSA name or a constant. */
201 tree valnum;
202 /* Statements to insert if needs_insertion is true. */
203 gimple_seq expr;
204
205 /* Unique identifier that all expressions with the same value have. */
206 unsigned int value_id;
207
208 /* Whether the SSA_NAME has been processed at least once. */
209 unsigned visited : 1;
210
211 /* Whether the SSA_NAME has no defining statement and thus an
212 insertion of such with EXPR as definition is required before
213 a use can be created of it. */
214 unsigned needs_insertion : 1;
215 } *vn_ssa_aux_t;
216
217 enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
218
219 /* Return the value numbering info for an SSA_NAME. */
220 bool has_VN_INFO (tree);
221 extern vn_ssa_aux_t VN_INFO (tree);
222 tree vn_get_expr_for (tree);
223 void scc_vn_restore_ssa_info (void);
224 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
225 tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
226 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
227 tree, tree *, vn_nary_op_t *);
228 vn_nary_op_t vn_nary_op_insert (tree, tree);
229 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
230 tree, tree *, tree, unsigned int);
231 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
232 vec<vn_reference_op_s> );
233 vec<vn_reference_op_s> vn_reference_operands_for_lookup (tree);
234 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
235 vec<vn_reference_op_s> ,
236 vn_reference_t *, vn_lookup_kind);
237 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *, bool);
238 void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
239 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
240 vec<vn_reference_op_s> ,
241 tree, unsigned int);
242
243 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
244 const_vn_nary_op_t const vno2);
245 bool vn_nary_may_trap (vn_nary_op_t);
246 bool vn_reference_may_trap (vn_reference_t);
247 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
248 unsigned int get_max_value_id (void);
249 unsigned int get_next_value_id (void);
250 unsigned int get_constant_value_id (tree);
251 unsigned int get_or_alloc_constant_value_id (tree);
252 bool value_id_constant_p (unsigned int);
253 tree fully_constant_vn_reference_p (vn_reference_t);
254 tree vn_nary_simplify (vn_nary_op_t);
255
256 unsigned do_rpo_vn (function *, edge, bitmap);
257 void run_rpo_vn (vn_lookup_kind);
258 unsigned eliminate_with_rpo_vn (bitmap);
259 void free_rpo_vn (void);
260
261 /* Valueize NAME if it is an SSA name, otherwise just return it. This hook
262 is initialized by run_scc_vn. */
263 extern tree (*vn_valueize) (tree);
264
265 /* Context that valueization should operate on. */
266 extern basic_block vn_context_bb;
267
268
269 #endif /* TREE_SSA_SCCVN_H */
270