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;
}
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;
}