tree-ssa-sccvn.h revision 1.11 
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  */
25bool expressions_equal_p (tree, tree);
26
27
28/* TOP of the VN lattice.  */
29extern tree VN_TOP;
30
31/* A predicated value.  */
32struct 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
48typedef 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;
67typedef 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
71static inline size_t
72sizeof_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
83typedef 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;
98typedef 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
106typedef 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;
122typedef vn_reference_op_s *vn_reference_op_t;
123typedef const vn_reference_op_s *const_vn_reference_op_t;
124
125inline unsigned
126vn_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
138typedef 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;
151typedef const struct vn_reference_s *const_vn_reference_t;
152
153typedef struct vn_constant_s
154{
155  unsigned int value_id;
156  hashval_t hashcode;
157  tree constant;
158} *vn_constant_t;
159
160enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
161enum 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
166static inline hashval_t
167vn_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
177static inline hashval_t
178vn_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
189static inline bool
190vn_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
196typedef 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
217enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
218
219/* Return the value numbering info for an SSA_NAME.  */
220bool has_VN_INFO (tree);
221extern vn_ssa_aux_t VN_INFO (tree);
222tree vn_get_expr_for (tree);
223void scc_vn_restore_ssa_info (void);
224tree vn_nary_op_lookup (tree, vn_nary_op_t *);
225tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
226tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
227			       tree, tree *, vn_nary_op_t *);
228vn_nary_op_t vn_nary_op_insert (tree, tree);
229vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
230				       tree, tree *, tree, unsigned int);
231bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
232				    vec<vn_reference_op_s> );
233vec<vn_reference_op_s> vn_reference_operands_for_lookup (tree);
234tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
235				 vec<vn_reference_op_s> ,
236				 vn_reference_t *, vn_lookup_kind);
237tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *, bool,
238			  tree * = NULL);
239void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
240vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
241					   vec<vn_reference_op_s> ,
242					   tree, unsigned int);
243
244bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
245		    const_vn_nary_op_t const vno2);
246bool vn_nary_may_trap (vn_nary_op_t);
247bool vn_reference_may_trap (vn_reference_t);
248bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
249unsigned int get_max_value_id (void);
250unsigned int get_next_value_id (void);
251unsigned int get_constant_value_id (tree);
252unsigned int get_or_alloc_constant_value_id (tree);
253bool value_id_constant_p (unsigned int);
254tree fully_constant_vn_reference_p (vn_reference_t);
255tree vn_nary_simplify (vn_nary_op_t);
256
257unsigned do_rpo_vn (function *, edge, bitmap);
258void run_rpo_vn (vn_lookup_kind);
259unsigned eliminate_with_rpo_vn (bitmap);
260void free_rpo_vn (void);
261
262/* Valueize NAME if it is an SSA name, otherwise just return it.  This hook
263   is initialized by run_scc_vn.  */
264extern tree (*vn_valueize) (tree);
265
266/* Context that valueization should operate on.  */
267extern basic_block vn_context_bb;
268
269
270#endif /* TREE_SSA_SCCVN_H  */
271