1 files changed, 4 insertions, 3 deletions
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 2d52f34..dd98b62 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -2679,11 +2679,12 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
       case Intrinsic::nvvm_round_ftz_f:
       case Intrinsic::nvvm_round_f:
       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.
+        // nvvm_round is lowered to PTX cvt.rni, which will round to nearest
+        // integer, choosing even integer if source is equidistant between two
+        // integers, so the semantics are closer to "rint" rather than "round".
         bool IsFTZ = nvvm::UnaryMathIntrinsicShouldFTZ(IntrinsicID);
         auto V = IsFTZ ? FTZPreserveSign(APF) : APF;
-        V.roundToIntegral(APFloat::rmNearestTiesToAway);
+        V.roundToIntegral(APFloat::rmNearestTiesToEven);
         return ConstantFP::get(Ty->getContext(), V);
       }