Re: [PATCH v2 2/2] libstdc++: use new built-in trait __is_scalar for std::is_scalar

[Ken Matsui <kmatsui@cs.washington.edu>]

On Wed, Jul 12, 2023 at 2:50 AM Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Sat, 8 Jul 2023 at 05:47, Ken Matsui via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
> >
> > This patch gets std::is_scalar to dispatch to new built-in trait
> > __is_scalar.
> >
> > libstdc++-v3/ChangeLog:
> >
> >         * include/std/type_traits (is_scalar): Use __is_scalar built-in
> >         trait.
> >         (is_scalar_v): Likewise.
>
> OK for trunk (conditional on the front-end change being committed
> first of course).
>

Thank you for your review!

Just to confirm, this approval does not include the [1/2] patch, does
it? Or, did you approve this entire patch series?

> conditional on the front-end change being committed first of course

Does this mean we want to commit this [2/2] patch before committing
the [1/2] patch in this case?

Also, can I tweak the commit message without being approved again,
such as attaching the benchmark result?

> >
> > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > ---
> >  libstdc++-v3/include/std/type_traits | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> > index 0e7a9c9c7f3..bc90b2c61ca 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -678,11 +678,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >      struct is_member_pointer;
> >
> >    /// is_scalar
> > +#if __has_builtin(__is_scalar)
> > +  template<typename _Tp>
> > +    struct is_scalar
> > +    : public __bool_constant<__is_scalar(_Tp)>
> > +    { };
> > +#else
> >    template<typename _Tp>
> >      struct is_scalar
> >      : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
> >                     is_member_pointer<_Tp>, is_null_pointer<_Tp>>::type
> >      { };
> > +#endif
> >
> >    /// is_compound
> >    template<typename _Tp>
> > @@ -3204,8 +3211,15 @@ template <typename _Tp>
> >    inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
> >  template <typename _Tp>
> >    inline constexpr bool is_object_v = is_object<_Tp>::value;
> > +
> > +#if __has_builtin(__is_scalar)
> > +template <typename _Tp>
> > +  inline constexpr bool is_scalar_v = __is_scalar(_Tp);
> > +#else
> >  template <typename _Tp>
> >    inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
> > +#endif
> > +
> >  template <typename _Tp>
> >    inline constexpr bool is_compound_v = is_compound<_Tp>::value;
> >  template <typename _Tp>
> > --
> > 2.41.0
> >
>