diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 07e96ff1a20..0c14dc32c50 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -10833,7 +10833,8 @@ static SDValue lowerVectorShuffle(SDValue Op, const X86Subtarget *Subtarget, // 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)) @@ -10850,8 +10851,18 @@ static SDValue lowerVectorShuffle(SDValue Op, const X86Subtarget *Subtarget, 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); + } } } |
