gcc/rtl-ssa/changes.h

   1 // RTL SSA classes related to changing instructions                 -*- C++ -*-
   2 // Copyright (C) 2020-2025 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   friend class function_info;
  36
  37 public:
  38   enum delete_action { DELETE };
  39
  40   // Construct a possible change to INSN.
  41   insn_change (insn_info *insn);
  42
  43   // Construct a possible deletion of INSN.
  44   insn_change (insn_info *insn, delete_action);
  45
  46   // The instruction that we would change.
  47   insn_info *insn () const { return m_insn; }
  48
  49   // The rtx_insn of the instruction that we would change.
  50   rtx_insn *rtl () const { return m_insn->rtl (); }
  51
  52   // The basic block that contains insn ().
  53   bb_info *bb () const { return m_insn->bb (); }
  54
  55   // The extended basic block that contains insn ().
  56   ebb_info *ebb () const { return m_insn->ebb (); }
  57
  58   // The uid of the instruction that we would change.
  59   unsigned int insn_uid () const { return m_insn->uid (); }
  60
  61   // The list of things that the original instruction defined and used.
  62   def_array old_defs () const { return m_insn->defs (); }
  63   use_array old_uses () const { return m_insn->uses (); }
  64
  65   // The cost of the original instruction, as calculated by the target.
  66   unsigned int old_cost () const { return m_insn->cost (); }
  67
  68   // Return true if the original instruction would simply be deleted,
  69   // rather than being replaced by a new instruction.
  70   bool is_deletion () const { return m_is_deletion; }
  71
  72   // Print a description of the change to PP.
  73   void print (pretty_printer *pp) const;
  74
  75   // Return an insn_change for deleting INSN.
  76   static insn_change delete_insn (insn_info *insn) { return { insn, DELETE }; }
  77
  78 private:
  79   // The value returned by insn ().
  80   insn_info *m_insn;
  81
  82 public:
  83   // The list of things that the new instruction would define and use.
  84   def_array new_defs;
  85   use_array new_uses;
  86
  87   // The range of instructions after which the instruction could be placed.
  88   // The range can include INSN itself: placing the instruction after either
  89   // INSN or INSN->prev_nondebug_insn () is equivalent to not moving the
  90   // instruction.
  91   insn_range_info move_range;
  92
  93   // The cost that the new instruction would have, as calculated by the target.
  94   unsigned int new_cost;
  95
  96 private:
  97   // The value returned by is_deletion ().
  98   bool m_is_deletion;
  99 };
 100
 101 void pp_insn_change (pretty_printer *, const insn_change &);
 102
 103 }
 104
 105 void dump (FILE *, const rtl_ssa::insn_change &);
 106
 107 void DEBUG_FUNCTION debug (const rtl_ssa::insn_change &);