diff options
Diffstat (limited to 'llvm/lib/Target/X86')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 9020eebe203..5fb3ece19f2 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -22968,7 +22968,8 @@ static SDValue LowerCTLZ(SDValue Op, const X86Subtarget &Subtarget, return Op; } -static SDValue LowerCTTZ(SDValue Op, SelectionDAG &DAG) { +static SDValue LowerCTTZ(SDValue Op, const X86Subtarget &Subtarget, + SelectionDAG &DAG) { MVT VT = Op.getSimpleValueType(); unsigned NumBits = VT.getScalarSizeInBits(); SDLoc dl(Op); @@ -22977,21 +22978,24 @@ static SDValue LowerCTTZ(SDValue Op, SelectionDAG &DAG) { SDValue N0 = Op.getOperand(0); SDValue Zero = DAG.getConstant(0, dl, VT); - // lsb(x) = (x & -x) - SDValue LSB = DAG.getNode(ISD::AND, dl, VT, N0, - DAG.getNode(ISD::SUB, dl, VT, Zero, N0)); + // Decompose 256-bit ops into smaller 128-bit ops. + if (VT.is256BitVector() && !Subtarget.hasInt256()) + return Lower256IntUnary(Op, DAG); - // cttz_undef(x) = (width - 1) - ctlz(lsb) + // cttz_undef(x) = (width - 1) - ctlz(x & -x) if (Op.getOpcode() == ISD::CTTZ_ZERO_UNDEF) { SDValue WidthMinusOne = DAG.getConstant(NumBits - 1, dl, VT); + SDValue LSB = DAG.getNode(ISD::AND, dl, VT, N0, + DAG.getNode(ISD::SUB, dl, VT, Zero, N0)); return DAG.getNode(ISD::SUB, dl, VT, WidthMinusOne, DAG.getNode(ISD::CTLZ, dl, VT, LSB)); } - // cttz(x) = ctpop(lsb - 1) + // cttz(x) = ctpop(~x & (x - 1)) SDValue One = DAG.getConstant(1, dl, VT); return DAG.getNode(ISD::CTPOP, dl, VT, - DAG.getNode(ISD::SUB, dl, VT, LSB, One)); + DAG.getNode(ISD::AND, dl, VT, DAG.getNOT(dl, N0, VT), + DAG.getNode(ISD::SUB, dl, VT, N0, One))); } assert(Op.getOpcode() == ISD::CTTZ && @@ -25918,7 +25922,7 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const { case ISD::CTLZ: case ISD::CTLZ_ZERO_UNDEF: return LowerCTLZ(Op, Subtarget, DAG); case ISD::CTTZ: - case ISD::CTTZ_ZERO_UNDEF: return LowerCTTZ(Op, DAG); + case ISD::CTTZ_ZERO_UNDEF: return LowerCTTZ(Op, Subtarget, DAG); case ISD::MUL: return LowerMUL(Op, Subtarget, DAG); case ISD::MULHS: case ISD::MULHU: return LowerMULH(Op, Subtarget, DAG); |
