diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 0193f2bfd58..2cb6ec376c4 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -35656,6 +35656,11 @@ static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG, unsigned IdxVal = cast<ConstantSDNode>(Idx)->getZExtValue(); MVT SubVecVT = SubVec.getSimpleValueType(); + // Inserting zeros into zeros is a nop. + if (ISD::isBuildVectorAllZeros(Vec.getNode()) && + ISD::isBuildVectorAllZeros(SubVec.getNode())) + return Vec; + // If this is an insert of an extract, combine to a shuffle. Don't do this // if the insert or extract can be represented with a subregister operation. if (SubVec.getOpcode() == ISD::EXTRACT_SUBVECTOR && |
