[Bug c++/107123] Size deduction for vector size in template fails

[milasudril at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107123

--- Comment #2 from milasudril at gmail dot com ---
> It would be nice to standardized the vector attribute.

Good features to have:

constexpr std::size (and also std::ssize)

template<class T>
inline constexpr std::is_simd_type_v = ...;

namespace std {
template<class T>
struct simd_element_type{
  using type = ...;
};

template<class T>
simd_element_type_t = typename simd_element_type<T>::type;
}

I belive the working paper is p2638r0

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2638r0.pdf