diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86ISelLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 1fb1aa12de6..978a7adb304 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -41212,6 +41212,15 @@ static SDValue combinePMULDQ(SDNode *N, SelectionDAG &DAG, if (ISD::isBuildVectorAllZeros(RHS.getNode())) return RHS; + // Aggressively peek through ops to get at the demanded low bits. + APInt DemandedMask = APInt::getLowBitsSet(64, 32); + SDValue DemandedLHS = DAG.GetDemandedBits(LHS, DemandedMask); + SDValue DemandedRHS = DAG.GetDemandedBits(RHS, DemandedMask); + if (DemandedLHS || DemandedRHS) + return DAG.getNode(N->getOpcode(), SDLoc(N), N->getValueType(0), + DemandedLHS ? DemandedLHS : LHS, + DemandedRHS ? DemandedRHS : RHS); + // PMULDQ/PMULUDQ only uses lower 32 bits from each vector element. const TargetLowering &TLI = DAG.getTargetLoweringInfo(); if (TLI.SimplifyDemandedBits(SDValue(N, 0), APInt::getAllOnesValue(64), DCI)) |
