diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86ISelLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 84 |
1 files changed, 74 insertions, 10 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 3bbe5fb70f6..d2d76da838c 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -8833,18 +8833,35 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG, unsigned Opcode = 0; // Check for x CC y ? x : y. - if (LHS == Cond.getOperand(0) && RHS == Cond.getOperand(1)) { + if (DAG.isEqualTo(LHS, Cond.getOperand(0)) && + DAG.isEqualTo(RHS, Cond.getOperand(1))) { switch (CC) { default: break; case ISD::SETULT: - if (!UnsafeFPMath) break; + // Converting this to a min would handle NaNs incorrectly, and swapping + // the operands would cause it to handle comparisons between positive + // and negative zero incorrectly. + if (!FiniteOnlyFPMath() && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) { + if (!UnsafeFPMath && + !(DAG.isKnownNeverZero(LHS) || DAG.isKnownNeverZero(RHS))) + break; + std::swap(LHS, RHS); + } Opcode = X86ISD::FMIN; break; case ISD::SETOLE: - if (!UnsafeFPMath) break; + // Converting this to a min would handle comparisons between positive + // and negative zero incorrectly. + if (!UnsafeFPMath && + !DAG.isKnownNeverZero(LHS) && !DAG.isKnownNeverZero(RHS)) + break; Opcode = X86ISD::FMIN; break; case ISD::SETULE: + // Converting this to a min would handle both negative zeros and NaNs + // incorrectly, but we can swap the operands to fix both. + std::swap(LHS, RHS); case ISD::SETOLT: case ISD::SETLT: case ISD::SETLE: @@ -8852,14 +8869,30 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG, break; case ISD::SETOGE: - if (!UnsafeFPMath) break; + // Converting this to a max would handle comparisons between positive + // and negative zero incorrectly. + if (!UnsafeFPMath && + !DAG.isKnownNeverZero(LHS) && !DAG.isKnownNeverZero(LHS)) + break; Opcode = X86ISD::FMAX; break; case ISD::SETUGT: - if (!UnsafeFPMath) break; + // Converting this to a max would handle NaNs incorrectly, and swapping + // the operands would cause it to handle comparisons between positive + // and negative zero incorrectly. + if (!FiniteOnlyFPMath() && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) { + if (!UnsafeFPMath && + !(DAG.isKnownNeverZero(LHS) || DAG.isKnownNeverZero(RHS))) + break; + std::swap(LHS, RHS); + } Opcode = X86ISD::FMAX; break; case ISD::SETUGE: + // Converting this to a max would handle both negative zeros and NaNs + // incorrectly, but we can swap the operands to fix both. + std::swap(LHS, RHS); case ISD::SETOGT: case ISD::SETGT: case ISD::SETGE: @@ -8867,18 +8900,34 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG, break; } // Check for x CC y ? y : x -- a min/max with reversed arms. - } else if (LHS == Cond.getOperand(1) && RHS == Cond.getOperand(0)) { + } else if (DAG.isEqualTo(LHS, Cond.getOperand(1)) && + DAG.isEqualTo(RHS, Cond.getOperand(0))) { switch (CC) { default: break; case ISD::SETOGE: - if (!UnsafeFPMath) break; + // Converting this to a min would handle comparisons between positive + // and negative zero incorrectly, and swapping the operands would + // cause it to handle NaNs incorrectly. + if (!UnsafeFPMath && + !(DAG.isKnownNeverZero(LHS) || DAG.isKnownNeverZero(RHS))) { + if (!FiniteOnlyFPMath() && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) + break; + std::swap(LHS, RHS); + } Opcode = X86ISD::FMIN; break; case ISD::SETUGT: - if (!UnsafeFPMath) break; + // Converting this to a min would handle NaNs incorrectly. + if (!UnsafeFPMath && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) + break; Opcode = X86ISD::FMIN; break; case ISD::SETUGE: + // Converting this to a min would handle both negative zeros and NaNs + // incorrectly, but we can swap the operands to fix both. + std::swap(LHS, RHS); case ISD::SETOGT: case ISD::SETGT: case ISD::SETGE: @@ -8886,14 +8935,29 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG, break; case ISD::SETULT: - if (!UnsafeFPMath) break; + // Converting this to a max would handle NaNs incorrectly. + if (!FiniteOnlyFPMath() && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) + break; Opcode = X86ISD::FMAX; break; case ISD::SETOLE: - if (!UnsafeFPMath) break; + // Converting this to a max would handle comparisons between positive + // and negative zero incorrectly, and swapping the operands would + // cause it to handle NaNs incorrectly. + if (!UnsafeFPMath && + !DAG.isKnownNeverZero(LHS) && !DAG.isKnownNeverZero(RHS)) { + if (!FiniteOnlyFPMath() && + (!DAG.isKnownNeverNaN(LHS) || !DAG.isKnownNeverNaN(RHS))) + break; + std::swap(LHS, RHS); + } Opcode = X86ISD::FMAX; break; case ISD::SETULE: + // Converting this to a max would handle both negative zeros and NaNs + // incorrectly, but we can swap the operands to fix both. + std::swap(LHS, RHS); case ISD::SETOLT: case ISD::SETLT: case ISD::SETLE: |
