include/llvm/CodeGen/GlobalISel/CombinerInfo.h

   1 //===- llvm/CodeGen/GlobalISel/CombinerInfo.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 /// Interface for Targets to specify which operations are combined how and when.
  10 ///
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_CODEGEN_GLOBALISEL_COMBINER_INFO_H
  14 #define LLVM_CODEGEN_GLOBALISEL_COMBINER_INFO_H
  15
  16 #include <cassert>
  17 namespace llvm {
  18
  19 class GISelChangeObserver;
  20 class LegalizerInfo;
  21 class MachineInstr;
  22 class MachineIRBuilder;
  23 class MachineRegisterInfo;
  24
  25 // Contains information relevant to enabling/disabling various combines for a
  26 // pass.
  27 class CombinerInfo {
  28 public:
  29   CombinerInfo(bool AllowIllegalOps, bool ShouldLegalizeIllegal,
  30                LegalizerInfo *LInfo)
  31       : IllegalOpsAllowed(AllowIllegalOps),
  32         LegalizeIllegalOps(ShouldLegalizeIllegal), LInfo(LInfo) {
  33     assert(((AllowIllegalOps || !LegalizeIllegalOps) || LInfo) &&
  34            "Expecting legalizerInfo when illegalops not allowed");
  35   }
  36   virtual ~CombinerInfo() = default;
  37   /// If \p IllegalOpsAllowed is false, the CombinerHelper will make use of
  38   /// the legalizerInfo to check for legality before each transformation.
  39   bool IllegalOpsAllowed; // TODO: Make use of this.
  40
  41   /// If \p LegalizeIllegalOps is true, the Combiner will also legalize the
  42   /// illegal ops that are created.
  43   bool LegalizeIllegalOps; // TODO: Make use of this.
  44   const LegalizerInfo *LInfo;
  45
  46   /// Attempt to combine instructions using MI as the root.
  47   ///
  48   /// Use Observer to report the creation, modification, and erasure of
  49   /// instructions. GISelChangeObserver will automatically report certain
  50   /// kinds of operations. These operations are:
  51   /// * Instructions that are newly inserted into the MachineFunction
  52   /// * Instructions that are erased from the MachineFunction.
  53   ///
  54   /// However, it is important to report instruction modification and this is
  55   /// not automatic.
  56   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
  57                        MachineIRBuilder &B) const = 0;
  58 };
  59 } // namespace llvm
  60
  61 #endif