diff options
| author | Duncan Sands <baldrick@free.fr> | 2008-07-11 16:54:57 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2008-07-11 16:54:57 +0000 |
| commit | edfba7e707a4f2f2e800843a7ef980c27d7f4eff (patch) | |
| tree | f1de28a47c1f6a8ed58c89371d07d5689797e836 /lib/CodeGen | |
| parent | dddc6291fb5274282a20d5923b50535d456d34a4 (diff) | |
Port a shift-by-1 optimization from LegalizeDAG: it
was presumably added after the rest of the code was
copied to LegalizeTypes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53459 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp | 7 |
1 files changed, 7 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, |