[PATCH] c++, libstdc++: Implement C++26 P2747R2 - constexpr placement new [PR115744]

[Jonathan Wakely]

On Wed, 3 Jul 2024 at 16:51, Jakub Jelinek wrote:
>
> On Wed, Jul 03, 2024 at 11:41:58AM -0400, Jason Merrill wrote:
> > On 7/3/24 10:37 AM, Jakub Jelinek wrote:
> > > +#if __cpp_lib_constexpr_new >= 202406L
> > > +# define _GLIBCXX_PLACEMENT_CONSTEXPR constexpr
> > > +#else
> > > +# define _GLIBCXX_PLACEMENT_CONSTEXPR inline
> > > +#endif
> >
> > I'm a bit curious why you want constexpr *or* inline rather than leaving the
> > inline keyword on the declaration and maybe adding constexpr.  The effect
> > should be the same either way, so just wondering.
>
> Just that the inline is then redundant.
> But I'll do whatever Jonathan wants (already added #undef of the macro after
> uses).

I have a mild preference (again :-) for what Jakub's patch does. Those
declarations are getting more and more verbose, so if we don't have
the 'inline' there (because it's part of the macro) then that seems a
little less cluttered.