gcc/rtl-ssa/changes.h

   1 // RTL SSA classes related to changing instructions                 -*- C++ -*-
   2 // Copyright (C) 2020-2021 Free Software Foundation, Inc.
   3 //
   4 // This file is part of GCC.
   5 //
   6 // GCC is free software; you can redistribute it and/or modify it under
   7 // the terms of the GNU General Public License as published by the Free
   8 // Software Foundation; either version 3, or (at your option) any later
   9 // version.
  10 //
  11 // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 // WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 // for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with GCC; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 namespace rtl_ssa {
  21
  22 // A class that describes a change that we're considering making to an
  23 // instruction.  There are three choices:
  24 //
  25 // (1) delete the instruction
  26 // (2) replace the instruction with a new instruction in-place
  27 // (3) replace the instruction with a new instruction at a different location
  28 //
  29 // Anything related to the "new instruction" is irrelevant for (1).
  30 //
  31 // The class doesn't actually change anything itself, it simply records
  32 // something that we might do.
  33 class insn_change
  34 {
  35 public:
  36   enum delete_action { DELETE };
  37
  38   // Construct a possible change to INSN.
  39   insn_change (insn_info *insn);
  40
  41   // Construct a possible deletion of INSN.
  42   insn_change (insn_info *insn, delete_action);
  43
  44   // The instruction that we would change.
  45   insn_info *insn () const { return m_insn; }
  46
  47   // The rtx_insn of the instruction that we would change.
  48   rtx_insn *rtl () const { return m_insn->rtl (); }
  49
  50   // The basic block that contains insn ().
  51   bb_info *bb () const { return m_insn->bb (); }
  52
  53   // The extended basic block that contains insn ().
  54   ebb_info *ebb () const { return m_insn->ebb (); }
  55
  56   // The uid of the instruction that we would change.
  57   unsigned int insn_uid () const { return m_insn->uid (); }
  58
  59   // The list of things that the original instruction defined and used.
  60   def_array old_defs () const { return m_insn->defs (); }
  61   use_array old_uses () const { return m_insn->uses (); }
  62
  63   // The cost of the original instruction, as calculated by the target.
  64   unsigned int old_cost () const { return m_insn->cost (); }
  65
  66   // Return true if the original instruction would simply be deleted,
  67   // rather than being replaced by a new instruction.
  68   bool is_deletion () const { return m_is_deletion; }
  69
  70   // Print a description of the change to PP.
  71   void print (pretty_printer *pp) const;
  72
  73   // Return an insn_change for deleting INSN.
  74   static insn_change delete_insn (insn_info *insn) { return { insn, DELETE }; }
  75
  76 private:
  77   // The value returned by insn ().
  78   insn_info *m_insn;
  79
  80 public:
  81   // The list of things that the new instruction would define and use.
  82   def_array new_defs;
  83   use_array new_uses;
  84
  85   // The range of instructions after which the instruction could be placed.
  86   // The range can include INSN itself: placing the instruction after either
  87   // INSN or INSN->prev_nondebug_insn () is equivalent to not moving the
  88   // instruction.
  89   insn_range_info move_range;
  90
  91   // The cost that the new instruction would have, as calculated by the target.
  92   unsigned int new_cost;
  93
  94 private:
  95   // The value returned by is_deletion ().
  96   bool m_is_deletion;
  97 };
  98
  99 // A class that represents a closure of the two-argument form of
 100 // insn_is_changing.  See the comment above the one-argument form
 101 // for details.
 102 class insn_is_changing_closure
 103 {
 104 public:
 105   insn_is_changing_closure (array_slice<insn_change *const> changes);
 106   bool operator() (const insn_info *) const;
 107
 108 private:
 109   array_slice<insn_change *const> m_changes;
 110 };
 111
 112 void pp_insn_change (pretty_printer *, const insn_change &);
 113
 114 }
 115
 116 void dump (FILE *, const rtl_ssa::insn_change &);
 117
 118 void DEBUG_FUNCTION debug (const rtl_ssa::insn_change &);