diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp index f46767f..5d572c4 100644 --- a/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ b/contrib/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -2941,6 +2941,18 @@ SDValue SelectionDAGLegalize::ExpandBitCount(unsigned Opc, SDValue Op, // This trivially expands to CTLZ. return DAG.getNode(ISD::CTLZ, dl, Op.getValueType(), Op); case ISD::CTLZ: { + EVT VT = Op.getValueType(); + unsigned len = VT.getSizeInBits(); + + if (TLI.isOperationLegalOrCustom(ISD::CTLZ_ZERO_UNDEF, VT)) { + EVT SetCCVT = getSetCCResultType(VT); + SDValue CTLZ = DAG.getNode(ISD::CTLZ_ZERO_UNDEF, dl, VT, Op); + SDValue Zero = DAG.getConstant(0, dl, VT); + SDValue SrcIsZero = DAG.getSetCC(dl, SetCCVT, Op, Zero, ISD::SETEQ); + return DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero, + DAG.getConstant(len, dl, VT), CTLZ); + } + // for now, we do this: // x = x | (x >> 1); // x = x | (x >> 2); @@ -2950,9 +2962,7 @@ SDValue SelectionDAGLegalize::ExpandBitCount(unsigned Opc, SDValue Op, // return popcount(~x); // // Ref: "Hacker's Delight" by Henry Warren - EVT VT = Op.getValueType(); EVT ShVT = TLI.getShiftAmountTy(VT, DAG.getDataLayout()); - unsigned len = VT.getSizeInBits(); for (unsigned i = 0; (1U << i) <= (len / 2); ++i) { SDValue Tmp3 = DAG.getConstant(1ULL << i, dl, ShVT); Op = DAG.getNode(ISD::OR, dl, VT, Op, |
