gcc/value-query.cc

   1 /* Support routines for value queries.
   2    Copyright (C) 2020-2021 Free Software Foundation, Inc.
   3    Contributed by Aldy Hernandez <aldyh@redhat.com> and
   4    Andrew MacLeod <amacleod@redhat.com>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "backend.h"
  26 #include "tree.h"
  27 #include "gimple.h"
  28 #include "ssa.h"
  29 #include "tree-pretty-print.h"
  30 #include "fold-const.h"
  31 #include "value-range-equiv.h"
  32 #include "value-query.h"
  33 #include "alloc-pool.h"
  34
  35 // value_query default methods.
  36
  37 tree
  38 value_query::value_on_edge (edge, tree name)
  39 {
  40   return value_of_expr (name);
  41 }
  42
  43 tree
  44 value_query::value_of_stmt (gimple *stmt, tree name)
  45 {
  46   if (!name)
  47     name = gimple_get_lhs (stmt);
  48
  49   gcc_checking_assert (!name || name == gimple_get_lhs (stmt));
  50
  51   if (name)
  52     return value_of_expr (name);
  53   return NULL_TREE;
  54 }
  55
  56 // range_query default methods.
  57
  58 bool
  59 range_query::range_on_edge (irange &r, edge, tree name)
  60 {
  61   return range_of_expr (r, name);
  62 }
  63
  64 bool
  65 range_query::range_of_stmt (irange &r, gimple *stmt, tree name)
  66 {
  67   if (!name)
  68     name = gimple_get_lhs (stmt);
  69
  70   gcc_checking_assert (!name || name == gimple_get_lhs (stmt));
  71
  72   if (name)
  73     return range_of_expr (r, name);
  74   return false;
  75 }
  76
  77 tree
  78 range_query::value_of_expr (tree name, gimple *stmt)
  79 {
  80   tree t;
  81   int_range_max r;
  82
  83   if (!irange::supports_type_p (TREE_TYPE (name)))
  84     return NULL_TREE;
  85
  86   if (range_of_expr (r, name, stmt))
  87     {
  88       // A constant used in an unreachable block oftens returns as UNDEFINED.
  89       // If the result is undefined, check the global value for a constant.
  90       if (r.undefined_p ())
  91         range_of_expr (r, name);
  92       if (r.singleton_p (&t))
  93         return t;
  94     }
  95   return NULL_TREE;
  96 }
  97
  98 tree
  99 range_query::value_on_edge (edge e, tree name)
 100 {
 101   tree t;
 102   int_range_max r;
 103
 104   if (!irange::supports_type_p (TREE_TYPE (name)))
 105     return NULL_TREE;
 106   if (range_on_edge (r, e, name))
 107     {
 108       // A constant used in an unreachable block oftens returns as UNDEFINED.
 109       // If the result is undefined, check the global value for a constant.
 110       if (r.undefined_p ())
 111         range_of_expr (r, name);
 112       if (r.singleton_p (&t))
 113         return t;
 114     }
 115   return NULL_TREE;
 116
 117 }
 118
 119 tree
 120 range_query::value_of_stmt (gimple *stmt, tree name)
 121 {
 122   tree t;
 123   int_range_max r;
 124
 125   if (!name)
 126     name = gimple_get_lhs (stmt);
 127
 128   gcc_checking_assert (!name || name == gimple_get_lhs (stmt));
 129
 130   if (!name || !irange::supports_type_p (TREE_TYPE (name)))
 131     return NULL_TREE;
 132   if (range_of_stmt (r, stmt, name) && r.singleton_p (&t))
 133     return t;
 134   return NULL_TREE;
 135
 136 }
 137
 138 // valuation_query support routines for value_range_equiv's.
 139
 140 class equiv_allocator : public object_allocator<value_range_equiv>
 141 {
 142 public:
 143   equiv_allocator ()
 144     : object_allocator<value_range_equiv> ("equiv_allocator pool") { }
 145 };
 146
 147 value_range_equiv *
 148 range_query::allocate_value_range_equiv ()
 149 {
 150   return new (equiv_alloc->allocate ()) value_range_equiv;
 151 }
 152
 153 void
 154 range_query::free_value_range_equiv (value_range_equiv *v)
 155 {
 156   equiv_alloc->remove (v);
 157 }
 158
 159 const class value_range_equiv *
 160 range_query::get_value_range (const_tree expr, gimple *stmt)
 161 {
 162   int_range_max r;
 163   if (range_of_expr (r, const_cast<tree> (expr), stmt))
 164     return new (equiv_alloc->allocate ()) value_range_equiv (r);
 165   return new (equiv_alloc->allocate ()) value_range_equiv (TREE_TYPE (expr));
 166 }
 167
 168 range_query::range_query ()
 169 {
 170   equiv_alloc = new equiv_allocator;
 171 }
 172
 173 range_query::~range_query ()
 174 {
 175   equiv_alloc->release ();
 176   delete equiv_alloc;
 177 }