On Mon, 20 Mar 2023 at 08:08, Ken Matsui <kmat...@cs.washington.edu> wrote:
>
> Ooh... Thank you for pointing that out!
>
> > The helper doesn't need to be defined for the case where we don't use it.
>
> I thought that macroing them out leads to compiler errors since users
> are possibly using those helpers. But do we not have to care about
> that?
No, absolutely not.
>
> ---
> libstdc++-v3/ChangeLog:
>
> * include/std/type_traits (remove_pointer): Use __remove_pointer built-in
> trait.
>
> ---
> diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> index 2bd607a8b8f..cba98091aad 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -2025,17 +2025,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
> template<typename _Tp, typename>
> struct __remove_pointer_helper
> - { typedef _Tp type; };
> + { using type = _Tp; };
>
> template<typename _Tp, typename _Up>
> struct __remove_pointer_helper<_Tp, _Up*>
> - { typedef _Up type; };
> + { using type = _Up; };
>
> /// remove_pointer
> +#if __has_builtin(__remove_pointer)
> + template<typename _Tp>
> + struct remove_pointer
> + { using type = __remove_pointer(_Tp); };
> +#else
> template<typename _Tp>
> struct remove_pointer
> : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
> { };
> +#endif
>
> template<typename _Tp, typename = void>
> struct __add_pointer_helper
>
> On Mon, Mar 20, 2023 at 12:57 AM Jonathan Wakely <jwakely....@gmail.com>
> wrote:
> >
> >
> >
> > On Mon, 20 Mar 2023, 07:32 Ken Matsui via Libstdc++,
> > <libstd...@gcc.gnu.org> wrote:
> >>
> >> CCing libstd...@gcc.gnu.org.
> >>
> >> On Sun, Mar 19, 2023 at 7:53 PM Ken Matsui <kmat...@cs.washington.edu>
> >> wrote:
> >> >
> >> > libstdc++-v3/ChangeLog:
> >> >
> >> > * include/std/type_traits (is_reference): Use __remove_pointer built-in
> >> > trait.
> >
> >
> > The changelog entry says is_reference but the patch is for remove_pointer.
> >
> >
> >> >
> >> > ---
> >> > diff --git a/libstdc++-v3/include/std/type_traits
> >> > b/libstdc++-v3/include/std/type_traits
> >> > index 2bd607a8b8f..cba98091aad 100644
> >> > --- a/libstdc++-v3/include/std/type_traits
> >> > +++ b/libstdc++-v3/include/std/type_traits
> >> > @@ -2025,17 +2025,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >> >
> >> > template<typename _Tp, typename>
> >> > struct __remove_pointer_helper
> >> > - { typedef _Tp type; };
> >> > + { using type = _Tp; };
> >> >
> >> > template<typename _Tp, typename _Up>
> >> > struct __remove_pointer_helper<_Tp, _Up*>
> >> > - { typedef _Up type; };
> >> > + { using type = _Up; };
> >
> >
> > The helper doesn't need to be defined for the case where we don't use it.
> >
> >
> >> >
> >> > /// remove_pointer
> >> > +#if __has_builtin(__remove_pointer)
> >> > + template<typename _Tp>
> >> > + struct remove_pointer
> >> > + { using type = __remove_pointer(_Tp); };
> >> > +#else
> >> > template<typename _Tp>
> >> > struct remove_pointer
> >> > : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
> >> > { };
> >> > +#endif
> >> >
> >> > template<typename _Tp, typename = void>
> >> > struct __add_pointer_helper
