diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp index 0a1571544b3..4400fed8fe0 100644 --- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -4187,21 +4187,20 @@ SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) { SDValue Zero = DAG.getConstant(0, LHS.getValueType()); - SDValue LHSPos = DAG.getSetCC(OType, LHS, Zero, ISD::SETGE); - SDValue RHSPos = DAG.getSetCC(OType, RHS, Zero, ISD::SETGE); - SDValue And1 = DAG.getNode(ISD::AND, OType, LHSPos, RHSPos); - - And1 = DAG.getNode(ISD::AND, OType, And1, - DAG.getSetCC(OType, Sum, Zero, ISD::SETLT)); - - SDValue LHSNeg = DAG.getSetCC(OType, LHS, Zero, ISD::SETLT); - SDValue RHSNeg = DAG.getSetCC(OType, RHS, Zero, ISD::SETLT); - SDValue And2 = DAG.getNode(ISD::AND, OType, LHSNeg, RHSNeg); - - And2 = DAG.getNode(ISD::AND, OType, And2, - DAG.getSetCC(OType, Sum, Zero, ISD::SETGE)); - - SDValue Cmp = DAG.getNode(ISD::OR, OType, And1, And2); + // LHSSign -> LHS >= 0 + // RHSSign -> RHS >= 0 + // SumSign -> Sum >= 0 + // + // Overflow -> (LHSSign == RHSSign) && (LHSSign != SumSign) + // + SDValue LHSSign = DAG.getSetCC(OType, LHS, Zero, ISD::SETGE); + SDValue RHSSign = DAG.getSetCC(OType, RHS, Zero, ISD::SETGE); + SDValue SignsEq = DAG.getSetCC(OType, LHSSign, RHSSign, ISD::SETEQ); + + SDValue SumSign = DAG.getSetCC(OType, Sum, Zero, ISD::SETGE); + SDValue SumSignNE = DAG.getSetCC(OType, LHSSign, SumSign, ISD::SETNE); + + SDValue Cmp = DAG.getNode(ISD::AND, OType, SignsEq, SumSignNE); MVT ValueVTs[] = { LHS.getValueType(), OType }; SDValue Ops[] = { Sum, Cmp }; |
