[C++知识库]c++ 自动转换数据类型

template <typename T>
struct CudaSupportedTypeImpl {
  using type = T;
};

template <>
struct CudaSupportedTypeImpl<long long> {
  using type = unsigned long long;
};

template <>
struct CudaSupportedTypeImpl<unsigned long> {
  using type =
      typename std::conditional<sizeof(unsigned long) == sizeof(unsigned int),
                                unsigned int, unsigned long long>::type;
};

template <>
struct CudaSupportedTypeImpl<long> {
  // This cast should be safe since module-2 addition should work fine. However,
  // signed overflow is not handled correctly since it's undefined behavior.
  using type = typename CudaSupportedTypeImpl<unsigned long>::type;
};

template <typename T>
using CudaSupportedType = typename CudaSupportedTypeImpl<T>::type;


template <typename T>
__device__ CudaSupportedType<T>* ToCudaSupportedPtr(T* ptr) {
  return reinterpret_cast<CudaSupportedType<T>*>(ptr);
}

使用：

template <typename T, typename U>
__device__ detail::ToTypeIfConvertible<U, T> GpuAtomicAdd(T* ptr, U value) {
  return atomicAdd(detail::ToCudaSupportedPtr(ptr), value);
}