1/* Tree SCC value numbering
2   Copyright (C) 2007-2015 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[1];
46} *vn_nary_op_t;
47typedef const struct vn_nary_op_s *const_vn_nary_op_t;
48
49/* Return the size of a vn_nary_op_t with LENGTH operands.  */
50
51static inline size_t
52sizeof_vn_nary_op (unsigned int length)
53{
54  return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
55}
56
57/* Phi nodes in the hashtable consist of their non-VN_TOP phi
58   arguments, and the basic block the phi is in. Result is the value
59   number of the operation, and hashcode is stored to avoid having to
60   calculate it repeatedly.  Phi nodes not in the same block are never
61   considered equivalent.  */
62
63typedef struct vn_phi_s
64{
65  /* Unique identifier that all expressions with the same value have. */
66  unsigned int value_id;
67  hashval_t hashcode;
68  vec<tree> phiargs;
69  basic_block block;
70  tree type;
71  tree result;
72} *vn_phi_t;
73typedef const struct vn_phi_s *const_vn_phi_t;
74
75/* Reference operands only exist in reference operations structures.
76   They consist of an opcode, type, and some number of operands.  For
77   a given opcode, some, all, or none of the operands may be used.
78   The operands are there to store the information that makes up the
79   portion of the addressing calculation that opcode performs.  */
80
81typedef struct vn_reference_op_struct
82{
83  ENUM_BITFIELD(tree_code) opcode : 16;
84  /* 1 for instrumented calls.  */
85  unsigned with_bounds : 1;
86  /* Constant offset this op adds or -1 if it is variable.  */
87  HOST_WIDE_INT off;
88  tree type;
89  tree op0;
90  tree op1;
91  tree op2;
92} vn_reference_op_s;
93typedef vn_reference_op_s *vn_reference_op_t;
94typedef const vn_reference_op_s *const_vn_reference_op_t;
95
96
97/* A reference operation in the hashtable is representation as
98   the vuse, representing the memory state at the time of
99   the operation, and a collection of operands that make up the
100   addressing calculation.  If two vn_reference_t's have the same set
101   of operands, they access the same memory location. We also store
102   the resulting value number, and the hashcode.  */
103
104typedef struct vn_reference_s
105{
106  /* Unique identifier that all expressions with the same value have. */
107  unsigned int value_id;
108  hashval_t hashcode;
109  tree vuse;
110  alias_set_type set;
111  tree type;
112  vec<vn_reference_op_s> operands;
113  tree result;
114  tree result_vdef;
115} *vn_reference_t;
116typedef const struct vn_reference_s *const_vn_reference_t;
117
118typedef struct vn_constant_s
119{
120  unsigned int value_id;
121  hashval_t hashcode;
122  tree constant;
123} *vn_constant_t;
124
125enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
126enum vn_kind vn_get_stmt_kind (gimple);
127
128/* Hash the type TYPE using bits that distinguishes it in the
129   types_compatible_p sense.  */
130
131static inline hashval_t
132vn_hash_type (tree type)
133{
134  return (INTEGRAL_TYPE_P (type)
135	  + (INTEGRAL_TYPE_P (type)
136	     ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
137}
138
139/* Hash the constant CONSTANT with distinguishing type incompatible
140   constants in the types_compatible_p sense.  */
141
142static inline hashval_t
143vn_hash_constant_with_type (tree constant)
144{
145  inchash::hash hstate;
146  inchash::add_expr (constant, hstate);
147  hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
148  return hstate.end ();
149}
150
151/* Compare the constants C1 and C2 with distinguishing type incompatible
152   constants in the types_compatible_p sense.  */
153
154static inline bool
155vn_constant_eq_with_type (tree c1, tree c2)
156{
157  return (expressions_equal_p (c1, c2)
158	  && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
159}
160
161typedef struct vn_ssa_aux
162{
163  /* Value number. This may be an SSA name or a constant.  */
164  tree valnum;
165  /* Representative expression, if not a direct constant. */
166  tree expr;
167
168  /* Unique identifier that all expressions with the same value have. */
169  unsigned int value_id;
170
171  /* SCC information.  */
172  unsigned int dfsnum;
173  unsigned int low;
174  unsigned visited : 1;
175  unsigned on_sccstack : 1;
176
177  /* Whether the representative expression contains constants.  */
178  unsigned has_constants : 1;
179  /* Whether the SSA_NAME has been value numbered already.  This is
180     only saying whether visit_use has been called on it at least
181     once.  It cannot be used to avoid visitation for SSA_NAME's
182     involved in non-singleton SCC's.  */
183  unsigned use_processed : 1;
184
185  /* Whether the SSA_NAME has no defining statement and thus an
186     insertion of such with EXPR as definition is required before
187     a use can be created of it.  */
188  unsigned needs_insertion : 1;
189} *vn_ssa_aux_t;
190
191typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
192
193/* Return the value numbering info for an SSA_NAME.  */
194extern vn_ssa_aux_t VN_INFO (tree);
195extern vn_ssa_aux_t VN_INFO_GET (tree);
196tree vn_get_expr_for (tree);
197bool run_scc_vn (vn_lookup_kind);
198void free_scc_vn (void);
199tree vn_nary_op_lookup (tree, vn_nary_op_t *);
200tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
201tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
202			       tree, tree *, vn_nary_op_t *);
203vn_nary_op_t vn_nary_op_insert (tree, tree);
204vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
205vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
206				       tree, tree *, tree, unsigned int);
207void vn_reference_fold_indirect (vec<vn_reference_op_s> *,
208				 unsigned int *);
209bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
210				    vec<vn_reference_op_s> );
211tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
212				 vec<vn_reference_op_s> ,
213				 vn_reference_t *, vn_lookup_kind);
214tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *, bool);
215void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
216vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
217					   vec<vn_reference_op_s> ,
218					   tree, unsigned int);
219
220bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
221		    const_vn_nary_op_t const vno2);
222bool vn_nary_may_trap (vn_nary_op_t);
223bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
224unsigned int get_max_value_id (void);
225unsigned int get_next_value_id (void);
226unsigned int get_constant_value_id (tree);
227unsigned int get_or_alloc_constant_value_id (tree);
228bool value_id_constant_p (unsigned int);
229tree fully_constant_vn_reference_p (vn_reference_t);
230
231/* Valueize NAME if it is an SSA name, otherwise just return it.  */
232
233static inline tree
234vn_valueize (tree name)
235{
236  if (TREE_CODE (name) == SSA_NAME)
237    {
238      tree tem = VN_INFO (name)->valnum;
239      return tem == VN_TOP ? name : tem;
240    }
241  return name;
242}
243
244#endif /* TREE_SSA_SCCVN_H  */
245