[Bug libstdc++/107929] std::experimental::simd needs to be reimplemented with GCC's vector extension

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107929

--- Comment #3 from cqwrteur <unlvsur at live dot com> ---
(In reply to Matthias Kretz (Vir) from comment #2)
> std::experimental::simd has always been implemented with GCC's vector
> extension. Also copy_from and copy_to are implemented with __builtin_memcpy.

The problem is that the compilation speed are very slow. immintrin.h header
should not be included