diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 891d401201f..9902ed76fa7 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -2322,6 +2322,27 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1, } } } + + if (!isLegalICmpImmediate(C1.getSExtValue())) { + // (X & -256) == 256 -> (X >> 8) == 1 + if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) && + N0.getOpcode() == ISD::AND && N0.hasOneUse()) { + if (ConstantSDNode *AndRHS = + dyn_cast<ConstantSDNode>(N0.getOperand(1))) { + const APInt &AndRHSC = AndRHS->getAPIntValue(); + if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) { + unsigned ShiftBits = AndRHSC.countTrailingZeros(); + EVT ShiftTy = DCI.isBeforeLegalize() ? + getPointerTy() : getShiftAmountTy(N0.getValueType()); + EVT CmpTy = N0.getValueType(); + SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0.getOperand(0), + DAG.getConstant(ShiftBits, ShiftTy)); + SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), CmpTy); + return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond); + } + } + } + } } if (isa<ConstantFPSDNode>(N0.getNode())) { |
