include/llvm/CodeGen/GlobalISel/CombinerHelper.h

   1 //===-- llvm/CodeGen/GlobalISel/CombinerHelper.h --------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===--------------------------------------------------------------------===//
   8 //
   9 /// This contains common combine transformations that may be used in a combine
  10 /// pass,or by the target elsewhere.
  11 /// Targets can pick individual opcode transformations from the helper or use
  12 /// tryCombine which invokes all transformations. All of the transformations
  13 /// return true if the MachineInstruction changed and false otherwise.
  14 //
  15 //===--------------------------------------------------------------------===//
  16
  17 #ifndef LLVM_CODEGEN_GLOBALISEL_COMBINER_HELPER_H
  18 #define LLVM_CODEGEN_GLOBALISEL_COMBINER_HELPER_H
  19
  20 #include "llvm/CodeGen/LowLevelType.h"
  21 #include "llvm/CodeGen/Register.h"
  22
  23 namespace llvm {
  24
  25 class GISelChangeObserver;
  26 class MachineIRBuilder;
  27 class MachineRegisterInfo;
  28 class MachineInstr;
  29 class MachineOperand;
  30
  31 struct PreferredTuple {
  32   LLT Ty;                // The result type of the extend.
  33   unsigned ExtendOpcode; // G_ANYEXT/G_SEXT/G_ZEXT
  34   MachineInstr *MI;
  35 };
  36
  37 class CombinerHelper {
  38   MachineIRBuilder &Builder;
  39   MachineRegisterInfo &MRI;
  40   GISelChangeObserver &Observer;
  41
  42 public:
  43   CombinerHelper(GISelChangeObserver &Observer, MachineIRBuilder &B);
  44
  45   /// MachineRegisterInfo::replaceRegWith() and inform the observer of the changes
  46   void replaceRegWith(MachineRegisterInfo &MRI, Register FromReg, Register ToReg) const;
  47
  48   /// Replace a single register operand with a new register and inform the
  49   /// observer of the changes.
  50   void replaceRegOpWith(MachineRegisterInfo &MRI, MachineOperand &FromRegOp,
  51                         Register ToReg) const;
  52
  53   /// If \p MI is COPY, try to combine it.
  54   /// Returns true if MI changed.
  55   bool tryCombineCopy(MachineInstr &MI);
  56   bool matchCombineCopy(MachineInstr &MI);
  57   void applyCombineCopy(MachineInstr &MI);
  58
  59   /// If \p MI is extend that consumes the result of a load, try to combine it.
  60   /// Returns true if MI changed.
  61   bool tryCombineExtendingLoads(MachineInstr &MI);
  62   bool matchCombineExtendingLoads(MachineInstr &MI, PreferredTuple &MatchInfo);
  63   void applyCombineExtendingLoads(MachineInstr &MI, PreferredTuple &MatchInfo);
  64
  65   bool matchCombineBr(MachineInstr &MI);
  66   bool tryCombineBr(MachineInstr &MI);
  67
  68   /// Try to transform \p MI by using all of the above
  69   /// combine functions. Returns true if changed.
  70   bool tryCombine(MachineInstr &MI);
  71 };
  72 } // namespace llvm
  73
  74 #endif