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 e3a880957ed..65d5ad3f242 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -29027,6 +29027,16 @@ static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG, EVT VT = N->getValueType(0); SDLoc dl(InputVector); + // Detect mmx extraction of all bits as a i64. It works better as a bitcast. + if (InputVector.getOpcode() == ISD::BITCAST && InputVector.hasOneUse() && + VT == MVT::i64 && SrcVT == MVT::v1i64 && isNullConstant(EltIdx)) { + SDValue MMXSrc = InputVector.getOperand(0); + + // The bitcast source is a direct mmx result. + if (MMXSrc.getValueType() == MVT::x86mmx) + return DAG.getBitcast(VT, InputVector); + } + // Detect mmx to i32 conversion through a v2i32 elt extract. if (InputVector.getOpcode() == ISD::BITCAST && InputVector.hasOneUse() && VT == MVT::i32 && SrcVT == MVT::v2i32 && isNullConstant(EltIdx)) { |
