Worked around a compiler bug in CUDA 9.1, which caused an "Internal Compiler Error (codegen): "there was an error in verifying the lgenfe output!". Apparently the compiler got confused by overloaded is_valid() if the input parameter was not passed as a reference in both cases.

src/core/kernels/kernels.cuh

@@ -426,7 +426,7 @@ cross(const AcReal3& a, const AcReal3& b)
 }
 
 static __host__ __device__ __forceinline__ bool
-is_valid(const AcReal a)
+is_valid(const AcReal& a)
 {
     return !isnan(a) && !isinf(a);
 }