Commit e722943e authored by Matt Arsenault's avatar Matt Arsenault
Browse files

AMDGPU: Factor out large flat offset splitting

parent c80d52e6

llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp

+3 −15
Original line number Diff line number Diff line
@@ -1742,22 +1742,10 @@ bool AMDGPUDAGToDAGISel::SelectFlatOffset(SDNode *N, 
        // into two pieces that are both >= 0 or both <= 0.



        SDLoc DL(N);

        uint64_t RemainderOffset = COffsetVal;

        uint64_t ImmField = 0;

        const unsigned NumBits = TII->getNumFlatOffsetBits(IsSigned);

        if (IsSigned) {

          // Use signed division by a power of two to truncate towards 0.

          int64_t D = 1LL << (NumBits - 1);

          RemainderOffset = (static_cast<int64_t>(COffsetVal) / D) * D;

          ImmField = COffsetVal - RemainderOffset;

        } else if (static_cast<int64_t>(COffsetVal) >= 0) {

          ImmField = COffsetVal & maskTrailingOnes<uint64_t>(NumBits);

          RemainderOffset = COffsetVal - ImmField;

        }

        assert(TII->isLegalFLATOffset(ImmField, AS, IsSigned));

        assert(RemainderOffset + ImmField == COffsetVal);

        uint64_t RemainderOffset;



        OffsetVal = ImmField;

        std::tie(OffsetVal, RemainderOffset)

          = TII->splitFlatOffset(COffsetVal, AS, IsSigned);



        SDValue AddOffsetLo =

            getMaterializedScalarImm32(Lo_32(RemainderOffset), DL);

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

+20 −0
Original line number Diff line number Diff line
@@ -6959,6 +6959,26 @@ bool SIInstrInfo::isLegalFLATOffset(int64_t Offset, unsigned AddrSpace, 
  return Signed ? isInt<13>(Offset) :isUInt<12>(Offset);

}



std::pair<int64_t, int64_t> SIInstrInfo::splitFlatOffset(int64_t COffsetVal,

                                                         unsigned AddrSpace,

                                                         bool IsSigned) const {

  int64_t RemainderOffset = COffsetVal;

  int64_t ImmField = 0;

  const unsigned NumBits = getNumFlatOffsetBits(IsSigned);

  if (IsSigned) {

    // Use signed division by a power of two to truncate towards 0.

    int64_t D = 1LL << (NumBits - 1);

    RemainderOffset = (COffsetVal / D) * D;

    ImmField = COffsetVal - RemainderOffset;

  } else if (COffsetVal >= 0) {

    ImmField = COffsetVal & maskTrailingOnes<uint64_t>(NumBits);

    RemainderOffset = COffsetVal - ImmField;

  }



  assert(isLegalFLATOffset(ImmField, AddrSpace, IsSigned));

  assert(RemainderOffset + ImmField == COffsetVal);

  return {ImmField, RemainderOffset};

}



// This must be kept in sync with the SIEncodingFamily class in SIInstrInfo.td

enum SIEncodingFamily {

llvm/lib/Target/AMDGPU/SIInstrInfo.h

+6 −0
Original line number Diff line number Diff line
@@ -1039,6 +1039,12 @@ public: 
  bool isLegalFLATOffset(int64_t Offset, unsigned AddrSpace,

                         bool Signed) const;



  /// Split \p COffsetVal into {immediate offset field, remainder offset}

  /// values.

  std::pair<int64_t, int64_t> splitFlatOffset(int64_t COffsetVal,

                                              unsigned AddrSpace,

                                              bool IsSigned) const;



  /// \brief Return a target-specific opcode if Opcode is a pseudo instruction.

  /// Return -1 if the target-specific opcode for the pseudo instruction does

  /// not exist. If Opcode is not a pseudo instruction, this is identity.