Add bit_cast function template to <Kokkos_BitManipulation.hpp>
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…class declaration within the body of the functor)
dalg24
commented
May 4, 2023
masterleinad
reviewed
May 4, 2023
dalg24
commented
May 4, 2023
Comment on lines
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| template <class To, class From> | ||
| [[nodiscard]] KOKKOS_FORCEINLINE_FUNCTION constexpr To bit_cast( | ||
| From const& src) { | ||
| To dst; | ||
| std::memcpy(&dst, &src, sizeof(To)); | ||
| return dst; | ||
| } |
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Looks like it's used in simd constructors.
kokkos/simd/src/Kokkos_SIMD_AVX512.hpp
Lines 261 to 264 in 26ae798
I'm not sure if I've seen it used in the test.
masterleinad
approved these changes
May 4, 2023
crtrott
requested changes
May 4, 2023
| template <typename To, typename From> | ||
| static KOKKOS_FUNCTION bool check(const From& from) { | ||
| using Kokkos::Experimental::bit_cast_builtin; | ||
| return bit_cast_builtin<From>(bit_cast_builtin<To>(from)) == from; |
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I would use my_memcmp here and pass both the from and to value in. Otherwise you could have something like bit_cast_builtin calls reverse order of bits and you still would pass?
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I wanted to have a few round trips checks and there is "coverage" for my_memcmp below in check 6 and 7 below
Co-authored-by: Daniel Arndt <arndtd@ornl.gov>
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This was the last function template missing that is present in the header
<bit>from the standard library.One thing worth noting is that
Kokkos::bit_castis not usable in constant expressions. It is not implementable as a library and needs compiler magic to work so we just can't declare itconstexpr.I went ahead and replaced the
Kokkos::Experimental::bit_castin the SIMD sub package. We had agreed we'd do so when it is provided by Core.