diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp | 7 | ||||
| -rw-r--r-- | test/CodeGen/X86/2008-07-11-SHLBy1.ll | 5 |
2 files changed, 12 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp index a1840f130f..4e3e21732b 100644 --- a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp +++ b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp @@ -1556,6 +1556,13 @@ void DAGTypeLegalizer::ExpandShiftByConstant(SDNode *N, unsigned Amt, } else if (Amt == NVTBits) { Lo = DAG.getConstant(0, NVT); Hi = InL; + } else if (Amt == 1) { + // Emit this X << 1 as X+X. + SDVTList VTList = DAG.getVTList(NVT, MVT::Flag); + SDOperand LoOps[2] = { InL, InL }; + Lo = DAG.getNode(ISD::ADDC, VTList, LoOps, 2); + SDOperand HiOps[3] = { InH, InH, Lo.getValue(1) }; + Hi = DAG.getNode(ISD::ADDE, VTList, HiOps, 3); } else { Lo = DAG.getNode(ISD::SHL, NVT, InL, DAG.getConstant(Amt, ShTy)); Hi = DAG.getNode(ISD::OR, NVT, diff --git a/test/CodeGen/X86/2008-07-11-SHLBy1.ll b/test/CodeGen/X86/2008-07-11-SHLBy1.ll new file mode 100644 index 0000000000..5b94a351cf --- /dev/null +++ b/test/CodeGen/X86/2008-07-11-SHLBy1.ll @@ -0,0 +1,5 @@ +; RUN: llvm-as < %s | llc -march=x86-64 -o - | not grep shr +define i128 @sl(i128 %x) { + %t = shl i128 %x, 1 + ret i128 %t +} |