case Intrinsic::ppc_altivec_vperm:
// Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
+ // Note that ppc_altivec_vperm has a big-endian bias, so when creating
+ // a vectorshuffle for little endian, we must undo the transformation
+ // performed on vec_perm in altivec.h. That is, we must complement
+ // the permutation mask with respect to 31 and reverse the order of
+ // V1 and V2.
if (Constant *Mask = dyn_cast<Constant>(II->getArgOperand(2))) {
assert(Mask->getType()->getVectorNumElements() == 16 &&
"Bad type for intrinsic!");
unsigned Idx =
cast<ConstantInt>(Mask->getAggregateElement(i))->getZExtValue();
Idx &= 31; // Match the hardware behavior.
+ if (DL && DL->isLittleEndian())
+ Idx = 31 - Idx;
if (!ExtractedElts[Idx]) {
+ Value *Op0ToUse = (DL && DL->isLittleEndian()) ? Op1 : Op0;
+ Value *Op1ToUse = (DL && DL->isLittleEndian()) ? Op0 : Op1;
ExtractedElts[Idx] =
- Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1,
+ Builder->CreateExtractElement(Idx < 16 ? Op0ToUse : Op1ToUse,
Builder->getInt32(Idx&15));
}