[Bug libstdc++/87106] Group move and destruction of the source, where possible, for speed

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87106

--- Comment #27 from Jonathan Wakely <redi at gcc dot gnu.org> ---
>           if constexpr (!is_trivial_v<T>)
>             if (is_default_constructible_v<_Tp> && (__OPTIMIZE__+0))

That would need to be 'if constexpr'

I'll stop now.