// When the number of V1 and V2 elements are the same, try to minimize the
// number of uses of V2 in the low half of the vector. When that is tied,
// ensure that the sum of indices for V1 is equal to or lower than the sum
- // indices for V2.
+ // indices for V2. When those are equal, try to ensure that the number of odd
+ // indices for V1 is lower than the number of odd indices for V2.
if (NumV1Elements == NumV2Elements) {
int LowV1Elements = 0, LowV2Elements = 0;
for (int M : SVOp->getMask().slice(0, NumElements / 2))
SumV2Indices += i;
else if (SVOp->getMask()[i] >= 0)
SumV1Indices += i;
- if (SumV2Indices < SumV1Indices)
+ if (SumV2Indices < SumV1Indices) {
return DAG.getCommutedVectorShuffle(*SVOp);
+ } else if (SumV2Indices == SumV1Indices) {
+ int NumV1OddIndices = 0, NumV2OddIndices = 0;
+ for (int i = 0, Size = SVOp->getMask().size(); i < Size; ++i)
+ if (SVOp->getMask()[i] >= NumElements)
+ NumV2OddIndices += i % 2;
+ else if (SVOp->getMask()[i] >= 0)
+ NumV1OddIndices += i % 2;
+ if (NumV2OddIndices < NumV1OddIndices)
+ return DAG.getCommutedVectorShuffle(*SVOp);
+ }
}
}