[Bug libstdc++/114958] use __builtin_shufflevector for std::experimental::simd split and concat (at least the common cases) to enable better optimizations

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114958

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I'm not sure the header should use __builtin_shufflevector unconditionally, I
think better test it using __has_builtin first.
GCC has it since GCC 12 I think, clang indeed much longer, not sure about other
compilers (ICC).