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Added proper support for fast 64bit integer division on CUDA

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This commit is contained in:
Benoit Steiner 2015-11-20 11:09:46 -08:00
parent f37a5f1c53
commit 383d1cc2ed
1 changed files with 13 additions and 20 deletions
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27
unsupported/Eigen/CXX11/src/Tensor/TensorIntDiv.h
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@ -61,13 +61,8 @@ namespace {
template <typename T>
struct DividerTraits {
#if defined(__SIZEOF_INT128__) && !defined(__CUDACC__)
typedef typename UnsignedTraits<T>::type type;
static const int N = sizeof(T) * 8;
#else
typedef uint32_t type;
static const int N = 32;
#endif
};
template <typename T>
@ -79,23 +74,17 @@ namespace {
#endif
}
#if defined(__CUDA_ARCH__)
template <typename T>
EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE uint64_t muluh(const uint64_t a, const T b) {
#if defined(__CUDA_ARCH__)
return __umul64hi(a, b);
}
#else
template <typename T>
EIGEN_ALWAYS_INLINE uint64_t muluh(const uint64_t a, const T b) {
#if defined(__SIZEOF_INT128__) && !defined(__CUDACC__)
#elif defined(__SIZEOF_INT128__)
__uint128_t v = static_cast<__uint128_t>(a) * static_cast<__uint128_t>(b);
return static_cast<uint64_t>(v >> 64);
#else
EIGEN_STATIC_ASSERT(sizeof(T) == 4, YOU_MADE_A_PROGRAMMING_MISTAKE);
return (a * b) >> 32;
return (TensorUInt128<static_val<0>, uint64_t>(a) * TensorUInt128<static_val<0>, uint64_t>(b)).upper();
#endif
}
#endif
template <int N, typename T>
struct DividerHelper {
@ -105,14 +94,18 @@ namespace {
}
};
#if defined(__SIZEOF_INT128__) && !defined(__CUDACC__)
template <typename T>
struct DividerHelper<64, T> {
static EIGEN_ALWAYS_INLINE uint64_t computeMultiplier(const int log_div, const T divider) {
static EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE uint64_t computeMultiplier(const int log_div, const T divider) {
#if defined(__SIZEOF_INT128__) && !defined(__CUDA_ARCH__)
return static_cast<uint64_t>((static_cast<__uint128_t>(1) << (64+log_div)) / static_cast<__uint128_t>(divider) - (static_cast<__uint128_t>(1) << 64) + 1);
#else
const uint64_t shift = 1ULL << log_div;
TensorUInt128<uint64_t, uint64_t> result = (TensorUInt128<uint64_t, static_val<0> >(shift, 0) / TensorUInt128<static_val<0>, uint64_t>(divider) - TensorUInt128<static_val<1>, static_val<0> >(1, 0) + TensorUInt128<static_val<0>, static_val<1> >(1));
return static_cast<uint64_t>(result);
#endif
}
};
#endif
}