gcc/tree-ssa-sccvn.h

   1 /* Tree SCC value numbering
   2    Copyright (C) 2007-2016 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   bool reverse;
  96 } vn_reference_op_s;
  97 typedef vn_reference_op_s *vn_reference_op_t;
  98 typedef const vn_reference_op_s *const_vn_reference_op_t;
  99
 100
 101 /* A reference operation in the hashtable is representation as
 102    the vuse, representing the memory state at the time of
 103    the operation, and a collection of operands that make up the
 104    addressing calculation.  If two vn_reference_t's have the same set
 105    of operands, they access the same memory location. We also store
 106    the resulting value number, and the hashcode.  */
 107
 108 typedef struct vn_reference_s
 109 {
 110   /* Unique identifier that all expressions with the same value have. */
 111   unsigned int value_id;
 112   hashval_t hashcode;
 113   tree vuse;
 114   alias_set_type set;
 115   tree type;
 116   vec<vn_reference_op_s> operands;
 117   tree result;
 118   tree result_vdef;
 119 } *vn_reference_t;
 120 typedef const struct vn_reference_s *const_vn_reference_t;
 121
 122 typedef struct vn_constant_s
 123 {
 124   unsigned int value_id;
 125   hashval_t hashcode;
 126   tree constant;
 127 } *vn_constant_t;
 128
 129 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 130 enum vn_kind vn_get_stmt_kind (gimple *);
 131
 132 /* Hash the type TYPE using bits that distinguishes it in the
 133    types_compatible_p sense.  */
 134
 135 static inline hashval_t
 136 vn_hash_type (tree type)
 137 {
 138   return (INTEGRAL_TYPE_P (type)
 139           + (INTEGRAL_TYPE_P (type)
 140              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 141 }
 142
 143 /* Hash the constant CONSTANT with distinguishing type incompatible
 144    constants in the types_compatible_p sense.  */
 145
 146 static inline hashval_t
 147 vn_hash_constant_with_type (tree constant)
 148 {
 149   inchash::hash hstate;
 150   inchash::add_expr (constant, hstate);
 151   hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
 152   return hstate.end ();
 153 }
 154
 155 /* Compare the constants C1 and C2 with distinguishing type incompatible
 156    constants in the types_compatible_p sense.  */
 157
 158 static inline bool
 159 vn_constant_eq_with_type (tree c1, tree c2)
 160 {
 161   return (expressions_equal_p (c1, c2)
 162           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 163 }
 164
 165 typedef struct vn_ssa_aux
 166 {
 167   /* Value number. This may be an SSA name or a constant.  */
 168   tree valnum;
 169   /* Statements to insert if needs_insertion is true.  */
 170   gimple_seq expr;
 171
 172   /* Unique identifier that all expressions with the same value have. */
 173   unsigned int value_id;
 174
 175   /* SCC information.  */
 176   unsigned int dfsnum;
 177   unsigned int low;
 178   unsigned visited : 1;
 179   unsigned on_sccstack : 1;
 180
 181   /* Whether the SSA_NAME has been value numbered already.  This is
 182      only saying whether visit_use has been called on it at least
 183      once.  It cannot be used to avoid visitation for SSA_NAME's
 184      involved in non-singleton SCC's.  */
 185   unsigned use_processed : 1;
 186
 187   /* Whether the SSA_NAME has no defining statement and thus an
 188      insertion of such with EXPR as definition is required before
 189      a use can be created of it.  */
 190   unsigned needs_insertion : 1;
 191 } *vn_ssa_aux_t;
 192
 193 enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
 194
 195 /* Return the value numbering info for an SSA_NAME.  */
 196 extern vn_ssa_aux_t VN_INFO (tree);
 197 extern vn_ssa_aux_t VN_INFO_GET (tree);
 198 tree vn_get_expr_for (tree);
 199 bool run_scc_vn (vn_lookup_kind);
 200 void free_scc_vn (void);
 201 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 202 tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
 203 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 204                                tree, tree *, vn_nary_op_t *);
 205 vn_nary_op_t vn_nary_op_insert (tree, tree);
 206 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 207                                        tree, tree *, tree, unsigned int);
 208 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 209                                     vec<vn_reference_op_s> );
 210 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 211                                  vec<vn_reference_op_s> ,
 212                                  vn_reference_t *, vn_lookup_kind);
 213 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 214 void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
 215 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 216                                            vec<vn_reference_op_s> ,
 217                                            tree, unsigned int);
 218
 219 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 220                     const_vn_nary_op_t const vno2);
 221 bool vn_nary_may_trap (vn_nary_op_t);
 222 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
 223 unsigned int get_max_value_id (void);
 224 unsigned int get_next_value_id (void);
 225 unsigned int get_constant_value_id (tree);
 226 unsigned int get_or_alloc_constant_value_id (tree);
 227 bool value_id_constant_p (unsigned int);
 228 tree fully_constant_vn_reference_p (vn_reference_t);
 229
 230 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 231
 232 static inline tree
 233 vn_valueize (tree name)
 234 {
 235   if (TREE_CODE (name) == SSA_NAME)
 236     {
 237       tree tem = VN_INFO (name)->valnum;
 238       return tem == VN_TOP ? name : tem;
 239     }
 240   return name;
 241 }
 242
 243 #endif /* TREE_SSA_SCCVN_H  */