gcc/tree-ssa-sccvn.h

   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  */
  25 bool expressions_equal_p (tree, tree);
  26
  27
  28 /* TOP of the VN lattice.  */
  29 extern 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
  36 typedef 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;
  47 typedef 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
  51 static inline size_t
  52 sizeof_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
  63 typedef 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;
  73 typedef 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
  81 typedef struct vn_reference_op_struct
  82 {
  83   ENUM_BITFIELD(tree_code) opcode : 16;
  84   /* 1 for instrumented calls.  */
  85   unsigned with_bounds : 1;
  86   /* Dependence info, used for [TARGET_]MEM_REF only.  */
  87   unsigned short clique;
  88   unsigned short base;
  89   /* Constant offset this op adds or -1 if it is variable.  */
  90   HOST_WIDE_INT off;
  91   tree type;
  92   tree op0;
  93   tree op1;
  94   tree op2;
  95 } vn_reference_op_s;
  96 typedef vn_reference_op_s *vn_reference_op_t;
  97 typedef const vn_reference_op_s *const_vn_reference_op_t;
  98
  99
 100 /* A reference operation in the hashtable is representation as
 101    the vuse, representing the memory state at the time of
 102    the operation, and a collection of operands that make up the
 103    addressing calculation.  If two vn_reference_t's have the same set
 104    of operands, they access the same memory location. We also store
 105    the resulting value number, and the hashcode.  */
 106
 107 typedef struct vn_reference_s
 108 {
 109   /* Unique identifier that all expressions with the same value have. */
 110   unsigned int value_id;
 111   hashval_t hashcode;
 112   tree vuse;
 113   alias_set_type set;
 114   tree type;
 115   vec<vn_reference_op_s> operands;
 116   tree result;
 117   tree result_vdef;
 118 } *vn_reference_t;
 119 typedef const struct vn_reference_s *const_vn_reference_t;
 120
 121 typedef struct vn_constant_s
 122 {
 123   unsigned int value_id;
 124   hashval_t hashcode;
 125   tree constant;
 126 } *vn_constant_t;
 127
 128 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 129 enum vn_kind vn_get_stmt_kind (gimple *);
 130
 131 /* Hash the type TYPE using bits that distinguishes it in the
 132    types_compatible_p sense.  */
 133
 134 static inline hashval_t
 135 vn_hash_type (tree type)
 136 {
 137   return (INTEGRAL_TYPE_P (type)
 138           + (INTEGRAL_TYPE_P (type)
 139              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 140 }
 141
 142 /* Hash the constant CONSTANT with distinguishing type incompatible
 143    constants in the types_compatible_p sense.  */
 144
 145 static inline hashval_t
 146 vn_hash_constant_with_type (tree constant)
 147 {
 148   inchash::hash hstate;
 149   inchash::add_expr (constant, hstate);
 150   hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
 151   return hstate.end ();
 152 }
 153
 154 /* Compare the constants C1 and C2 with distinguishing type incompatible
 155    constants in the types_compatible_p sense.  */
 156
 157 static inline bool
 158 vn_constant_eq_with_type (tree c1, tree c2)
 159 {
 160   return (expressions_equal_p (c1, c2)
 161           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 162 }
 163
 164 typedef struct vn_ssa_aux
 165 {
 166   /* Value number. This may be an SSA name or a constant.  */
 167   tree valnum;
 168   /* Representative expression, if not a direct constant. */
 169   tree expr;
 170
 171   /* Unique identifier that all expressions with the same value have. */
 172   unsigned int value_id;
 173
 174   /* SCC information.  */
 175   unsigned int dfsnum;
 176   unsigned int low;
 177   unsigned visited : 1;
 178   unsigned on_sccstack : 1;
 179
 180   /* Whether the representative expression contains constants.  */
 181   unsigned has_constants : 1;
 182   /* Whether the SSA_NAME has been value numbered already.  This is
 183      only saying whether visit_use has been called on it at least
 184      once.  It cannot be used to avoid visitation for SSA_NAME's
 185      involved in non-singleton SCC's.  */
 186   unsigned use_processed : 1;
 187
 188   /* Whether the SSA_NAME has no defining statement and thus an
 189      insertion of such with EXPR as definition is required before
 190      a use can be created of it.  */
 191   unsigned needs_insertion : 1;
 192 } *vn_ssa_aux_t;
 193
 194 enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
 195
 196 /* Return the value numbering info for an SSA_NAME.  */
 197 extern vn_ssa_aux_t VN_INFO (tree);
 198 extern vn_ssa_aux_t VN_INFO_GET (tree);
 199 tree vn_get_expr_for (tree);
 200 bool run_scc_vn (vn_lookup_kind);
 201 void free_scc_vn (void);
 202 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 203 tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
 204 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 205                                tree, tree *, vn_nary_op_t *);
 206 vn_nary_op_t vn_nary_op_insert (tree, tree);
 207 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 208                                        tree, tree *, tree, unsigned int);
 209 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 210                                     vec<vn_reference_op_s> );
 211 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 212                                  vec<vn_reference_op_s> ,
 213                                  vn_reference_t *, vn_lookup_kind);
 214 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 215 void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
 216 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 217                                            vec<vn_reference_op_s> ,
 218                                            tree, unsigned int);
 219
 220 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 221                     const_vn_nary_op_t const vno2);
 222 bool vn_nary_may_trap (vn_nary_op_t);
 223 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
 224 unsigned int get_max_value_id (void);
 225 unsigned int get_next_value_id (void);
 226 unsigned int get_constant_value_id (tree);
 227 unsigned int get_or_alloc_constant_value_id (tree);
 228 bool value_id_constant_p (unsigned int);
 229 tree fully_constant_vn_reference_p (vn_reference_t);
 230
 231 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 232
 233 static inline tree
 234 vn_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  */