static bool isByteSwap64(ShuffleVectorInst &SI, SmallVector<int, 16>&RefMasks)
{

    RefMasks.clear();
    unsigned VWidth = cast<VectorType>(SI.getType())->getNumElements();
    VectorType *LHS = cast<VectorType>(SI.getOperand(0)->getType());
    VectorType *RHS = cast<VectorType>(SI.getOperand(1)->getType());

    IntegerType *IT = dyn_cast<IntegerType>(LHS->getElementType());
    //When Element Type is not IntegerType or the Result's element number
    //can't be divided by 8, return false
    //TODO:Need to check all masks are all constants.
    if (IT == nullptr
        || ! IT->isIntegerTy(8)
        || VWidth % 8 != 0) {
        return false;
    }

    SmallVector<int, 16> Masks(SI.getShuffleMask());
    bool isByteSwap = true;

    for (unsigned i = 0; i < VWidth / 8; ++i) {
        unsigned base = Masks[i * 8];
        if (base % 8 != 7) {
            isByteSwap = false;
            break;
        }

        for (unsigned j = 1; j < 8; ++j) {
            if (base - Masks[i * 8 + j] != j) {
                isByteSwap = false;
                break;
            }
        }

        if (isByteSwap) {
            RefMasks.push_back(base / 8);
        } else {
            break;
        }
    }

    if (!isByteSwap) {
        RefMasks.clear();
    }

    return isByteSwap;
}
Ejemplo n.º 2
0
bool Scalarizer::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
  VectorType *VT = dyn_cast<VectorType>(SVI.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  Scatterer Op0 = scatter(&SVI, SVI.getOperand(0));
  Scatterer Op1 = scatter(&SVI, SVI.getOperand(1));
  ValueVector Res;
  Res.resize(NumElems);

  for (unsigned I = 0; I < NumElems; ++I) {
    int Selector = SVI.getMaskValue(I);
    if (Selector < 0)
      Res[I] = UndefValue::get(VT->getElementType());
    else if (unsigned(Selector) < Op0.size())
      Res[I] = Op0[Selector];
    else
      Res[I] = Op1[Selector - Op0.size()];
  }
  gather(&SVI, Res);
  return true;
}