diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp index f5a88b6e0368e..e71ba5ea5521e 100644 --- a/llvm/lib/Analysis/ConstantFolding.cpp +++ b/llvm/lib/Analysis/ConstantFolding.cpp @@ -2677,11 +2677,14 @@ static Constant *ConstantFoldScalarCall1(StringRef Name, case Intrinsic::nvvm_round_ftz_f: case Intrinsic::nvvm_round_f: - case Intrinsic::nvvm_round_d: - return ConstantFoldFP( - round, APF, Ty, - nvvm::GetNVVMDenromMode( - nvvm::UnaryMathIntrinsicShouldFTZ(IntrinsicID))); + case Intrinsic::nvvm_round_d: { + // Use APFloat implementation instead of native libm call, as some + // implementations (e.g. on PPC) do not preserve the sign of negative 0. + bool IsFTZ = nvvm::UnaryMathIntrinsicShouldFTZ(IntrinsicID); + auto V = IsFTZ ? FTZPreserveSign(APF) : APF; + V.roundToIntegral(APFloat::rmNearestTiesToAway); + return ConstantFP::get(Ty->getContext(), V); + } case Intrinsic::nvvm_saturate_ftz_f: case Intrinsic::nvvm_saturate_d: