diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86ISelLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 675a48fbed4..7df0fa1ffc8 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -34678,6 +34678,16 @@ static SDValue combineMulToPMADDWD(SDNode *N, SelectionDAG &DAG, SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); + + // If we are zero extending two steps without SSE4.1, its better to reduce + // the vmul width instead. + if (!Subtarget.hasSSE41() && + (N0.getOpcode() == ISD::ZERO_EXTEND && + N0.getOperand(0).getScalarValueSizeInBits() <= 8) && + (N1.getOpcode() == ISD::ZERO_EXTEND && + N1.getOperand(0).getScalarValueSizeInBits() <= 8)) + return SDValue(); + APInt Mask17 = APInt::getHighBitsSet(32, 17); if (!DAG.MaskedValueIsZero(N1, Mask17) || !DAG.MaskedValueIsZero(N0, Mask17)) |
