Пример #1
0
// Select constant vector splats.
//
// In addition to the requirements of selectVSplat(), this function returns
// true and sets Imm if:
// * The splat value is the same width as the elements of the vector
// * The splat value fits in an integer with the specified signed-ness and
//   width.
//
// This function looks through ISD::BITCAST nodes.
// TODO: This might not be appropriate for big-endian MSA since BITCAST is
//       sometimes a shuffle in big-endian mode.
//
// It's worth noting that this function is not used as part of the selection
// of ldi.[bhwd] since it does not permit using the wrong-typed ldi.[bhwd]
// instruction to achieve the desired bit pattern. ldi.[bhwd] is selected in
// MipsSEDAGToDAGISel::selectNode.
bool MipsSEDAGToDAGISel::
selectVSplatCommon(SDValue N, SDValue &Imm, bool Signed,
                   unsigned ImmBitSize) const {
  APInt ImmValue;
  EVT EltTy = N->getValueType(0).getVectorElementType();

  if (N->getOpcode() == ISD::BITCAST)
    N = N->getOperand(0);

  if (selectVSplat (N.getNode(), ImmValue) &&
      ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
    if (( Signed && ImmValue.isSignedIntN(ImmBitSize)) ||
        (!Signed && ImmValue.isIntN(ImmBitSize))) {
      Imm = CurDAG->getTargetConstant(ImmValue, EltTy);
      return true;
    }
  }

  return false;
}