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222fa451a2
Pull Request resolved: https://github.com/pytorch/pytorch/pull/158976 Approved by: https://github.com/albanD, https://github.com/desertfire
51 lines
1.4 KiB
C++
51 lines
1.4 KiB
C++
#pragma once
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#include <cstring>
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#include <type_traits>
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#include <torch/headeronly/macros/Macros.h>
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#if __has_include(<bit>) && (defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L)
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#include <bit>
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#define C10_HAVE_STD_BIT_CAST 1
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#else
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#define C10_HAVE_STD_BIT_CAST 0
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#endif // __has_include(<bit>) && (__cplusplus >= 202002L ||
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// (defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L))
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namespace torch::headeronly {
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#if C10_HAVE_STD_BIT_CAST
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using std::bit_cast;
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#else
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// Implementations of std::bit_cast() from C++ 20.
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//
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// This is a less sketchy version of reinterpret_cast.
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//
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// See https://en.cppreference.com/w/cpp/numeric/bit_cast for more
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// information as well as the source of our implementations.
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template <class To, class From>
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C10_HOST_DEVICE std::enable_if_t<
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sizeof(To) == sizeof(From) && std::is_trivially_copyable_v<From> &&
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std::is_trivially_copyable_v<To>,
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To>
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// constexpr support needs compiler magic
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bit_cast(const From& src) noexcept {
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static_assert(
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std::is_trivially_constructible_v<To>,
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"This implementation additionally requires "
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"destination type to be trivially constructible");
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To dst;
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std::memcpy(&dst, &src, sizeof(To));
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return dst;
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}
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#endif // C10_HAVE_STD_BIT_CAST
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#undef C10_HAVE_STD_BIT_CAST
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} // namespace torch::headeronly
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namespace c10 {
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using torch::headeronly::bit_cast;
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} // namespace c10
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