gcc/gimple-range-gori.h

   1 /* Header file for gimple range GORI structures.
   2    Copyright (C) 2017-2021 Free Software Foundation, Inc.
   3    Contributed by Andrew MacLeod <amacleod@redhat.com>
   4    and Aldy Hernandez <aldyh@redhat.com>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  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 #ifndef GCC_GIMPLE_RANGE_GORI_H
  23 #define GCC_GIMPLE_RANGE_GORI_H
  24
  25 // RANGE_DEF_CHAIN is used to determine which SSA names in a block can
  26 // have range information calculated for them, and what the
  27 // dependencies on each other are.
  28
  29 class range_def_chain
  30 {
  31 public:
  32   range_def_chain ();
  33   ~range_def_chain ();
  34   tree depend1 (tree name) const;
  35   tree depend2 (tree name) const;
  36   bool in_chain_p (tree name, tree def);
  37   bool chain_import_p (tree name, tree import);
  38   void register_dependency (tree name, tree ssa1, basic_block bb = NULL);
  39   void dump (FILE *f, basic_block bb, const char *prefix = NULL);
  40 protected:
  41   bool has_def_chain (tree name);
  42   bool def_chain_in_bitmap_p (tree name, bitmap b);
  43   void add_def_chain_to_bitmap (bitmap b, tree name);
  44   bitmap get_def_chain (tree name);
  45   bitmap get_imports (tree name);
  46   bitmap_obstack m_bitmaps;
  47 private:
  48   struct rdc {
  49    tree ssa1;           // First direct dependency
  50    tree ssa2;           // Second direct dependency
  51    bitmap bm;           // All dependencies
  52    bitmap m_import;
  53   };
  54   vec<rdc> m_def_chain; // SSA_NAME : def chain components.
  55   void set_import (struct rdc &data, tree imp, bitmap b);
  56   int m_logical_depth;
  57 };
  58
  59 // Return the first direct dependency for NAME, if there is one.
  60 // Direct dependencies are those which occur on the defintion statement.
  61 // Only the first 2 such names are cached.
  62
  63 inline tree
  64 range_def_chain::depend1 (tree name) const
  65 {
  66   unsigned v = SSA_NAME_VERSION (name);
  67   if (v >= m_def_chain.length ())
  68     return NULL_TREE;
  69   return m_def_chain[v].ssa1;
  70 }
  71
  72 // Return the second direct dependency for NAME, if there is one.
  73
  74 inline tree
  75 range_def_chain::depend2 (tree name) const
  76 {
  77   unsigned v = SSA_NAME_VERSION (name);
  78   if (v >= m_def_chain.length ())
  79     return NULL_TREE;
  80   return m_def_chain[v].ssa2;
  81 }
  82
  83 // GORI_MAP is used to accumulate what SSA names in a block can
  84 // generate range information, and provides tools for the block ranger
  85 // to enable it to efficiently calculate these ranges.
  86
  87 class gori_map : public range_def_chain
  88 {
  89 public:
  90   gori_map ();
  91   ~gori_map ();
  92
  93   bool is_export_p (tree name, basic_block bb = NULL);
  94   bool is_import_p (tree name, basic_block bb);
  95   bitmap exports (basic_block bb);
  96   bitmap imports (basic_block bb);
  97   void set_range_invariant (tree name);
  98
  99   void dump (FILE *f);
 100   void dump (FILE *f, basic_block bb, bool verbose = true);
 101 private:
 102   vec<bitmap> m_outgoing;       // BB: Outgoing ranges calculatable on edges
 103   vec<bitmap> m_incoming;       // BB: Incoming ranges which can affect exports.
 104   bitmap m_maybe_variant;       // Names which might have outgoing ranges.
 105   void maybe_add_gori (tree name, basic_block bb);
 106   void calculate_gori (basic_block bb);
 107 };
 108
 109
 110 // This class is used to determine which SSA_NAMES can have ranges
 111 // calculated for them on outgoing edges from basic blocks.  This represents
 112 // ONLY the effect of the basic block edge->src on a range.
 113 //
 114 // There are 2 primary entry points:
 115 //
 116 // has_edge_range_p (tree name, edge e)
 117 //   returns true if the outgoing edge *may* be able to produce range
 118 //   information for ssa_name NAME on edge E.
 119 //   FALSE is returned if this edge does not affect the range of NAME.
 120 //   if no edge is specified, return TRUE if name may have a value calculated
 121 //   on *ANY* edge that has been seen.  FALSE indicates that the global value
 122 //   is applicable everywhere that has been processed.
 123 //
 124 // outgoing_edge_range_p (irange &range, edge e, tree name)
 125 //   Actually does the calculation of RANGE for name on E
 126 //   This represents application of whatever static range effect edge E
 127 //   may have on NAME, not any cumulative effect.
 128
 129 // There are also some internal APIs
 130 //
 131 // ssa_range_in_bb ()  is an internal routine which is used to start any
 132 // calculation chain using SSA_NAMES which come from outside the block. ie
 133 //      a_2 = b_4 - 8
 134 //      if (a_2 < 30)
 135 // on the true edge, a_2 is known to be [0, 29]
 136 // b_4 can be calculated as [8, 37]
 137 // during this calculation, b_4 is considered an "import" and ssa_range_in_bb
 138 // is queried for a starting range which is used in the calculation.
 139 // A default value of VARYING provides the raw static info for the edge.
 140 //
 141 // If there is any known range for b_4 coming into this block, it can refine
 142 // the results.  This allows for cascading results to be propogated.
 143 // if b_4 is [100, 200] on entry to the block, feeds into the calculation
 144 // of a_2 = [92, 192], and finally on the true edge the range would be
 145 // an empty range [] because it is not possible for the true edge to be taken.
 146 //
 147 // expr_range_in_bb is simply a wrapper which calls ssa_range_in_bb for
 148 // SSA_NAMES and otherwise simply calculates the range of the expression.
 149 //
 150 // The remaining routines are internal use only.
 151
 152 class gori_compute : public gori_map
 153 {
 154 public:
 155   gori_compute ();
 156   bool outgoing_edge_range_p (irange &r, edge e, tree name);
 157   bool has_edge_range_p (tree name, edge e = NULL);
 158   void dump (FILE *f);
 159 protected:
 160   virtual void ssa_range_in_bb (irange &r, tree name, basic_block bb);
 161   bool compute_operand_range (irange &r, gimple *stmt,
 162                               const irange &lhs, tree name);
 163
 164   void expr_range_at_stmt (irange &r, tree expr, gimple *s);
 165   bool compute_logical_operands (irange &r, gimple *stmt,
 166                                  const irange &lhs,
 167                                  tree name);
 168   void compute_logical_operands_in_chain (class tf_range &range,
 169                                           gimple *stmt, const irange &lhs,
 170                                           tree name, tree op,
 171                                           bool op_in_chain);
 172   bool optimize_logical_operands (tf_range &range, gimple *stmt,
 173                                   const irange &lhs, tree name, tree op);
 174   bool logical_combine (irange &r, enum tree_code code, const irange &lhs,
 175                         const class tf_range &op1_range,
 176                         const class tf_range &op2_range);
 177   int_range<2> m_bool_zero;           // Boolean false cached.
 178   int_range<2> m_bool_one;            // Boolean true cached.
 179
 180 private:
 181   bool compute_operand_range_switch (irange &r, gswitch *stmt,
 182                                      const irange &lhs, tree name);
 183   bool compute_name_range_op (irange &r, gimple *stmt, const irange &lhs,
 184                               tree name);
 185   bool compute_operand1_range (irange &r, gimple *stmt, const irange &lhs,
 186                                tree name);
 187   bool compute_operand2_range (irange &r, gimple *stmt, const irange &lhs,
 188                                tree name);
 189   bool compute_operand1_and_operand2_range (irange &r, gimple *stmt,
 190                                             const irange &lhs, tree name);
 191
 192   gimple_outgoing_range outgoing;       // Edge values for COND_EXPR & SWITCH_EXPR.
 193 };
 194
 195
 196 // For each name that is an import into BB's exports..
 197 #define FOR_EACH_GORI_IMPORT_NAME(gori, bb, name)                       \
 198   for (gori_export_iterator iter ((gori).imports ((bb)));       \
 199        ((name) = iter.get_name ());                             \
 200        iter.next ())
 201
 202 // For each name possibly exported from block BB.
 203 #define FOR_EACH_GORI_EXPORT_NAME(gori, bb, name)               \
 204   for (gori_export_iterator iter ((gori).exports ((bb)));       \
 205        ((name) = iter.get_name ());                             \
 206        iter.next ())
 207
 208 // Used to assist with iterating over the GORI export list in various ways
 209 class gori_export_iterator {
 210 public:
 211   gori_export_iterator (bitmap b);
 212   void next ();
 213   tree get_name ();
 214 protected:
 215   bitmap bm;
 216   bitmap_iterator bi;
 217   unsigned y;
 218 };
 219
 220 #endif // GCC_GIMPLE_RANGE_GORI_H