On Sun, Jul 16, 2023 at 5:32 AM François Dumont <frs.dum...@gmail.com> wrote:
>
>
> On 15/07/2023 06:55, Ken Matsui via Libstdc++ wrote:
> > This patch optimizes the performance of the is_arithmetic trait by
> > dispatching to the new __is_arithmetic built-in trait.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/type_traits (is_arithmetic): Use __is_arithmetic
> > built-in trait.
> > (is_arithmetic_v): Likewise.
> >
> > Signed-off-by: Ken Matsui <kmat...@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..7ebbe04c77b 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -655,10 +655,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { };
> >
> > /// is_arithmetic
> > +#if __has_builtin(__is_arithmetic)
> > + template<typename _Tp>
> > + struct is_arithmetic
> > + : public __bool_constant<__is_arithmetic(_Tp)>
> > + { };
> > +#else
> > template<typename _Tp>
> > struct is_arithmetic
> > : public __or_<is_integral<_Tp>, is_floating_point<_Tp>>::type
> > { };
> > +#endif
> >
> > /// is_fundamental
> > template<typename _Tp>
> > @@ -3198,8 +3205,15 @@ template <typename _Tp>
> > inline constexpr bool is_reference_v<_Tp&> = true;
> > template <typename _Tp>
> > inline constexpr bool is_reference_v<_Tp&&> = true;
> > +
> > +#if __has_builtin(__is_arithmetic)
> > +template <typename _Tp>
> > + inline constexpr bool is_arithmetic_v = __is_arithmetic(_Tp);
> > +#else
> > template <typename _Tp>
> > inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
> > +#endif
> > +
> > template <typename _Tp>
> > inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
> > template <typename _Tp>
>
> Same remark as the one I did for __is_pointer in cpp_type_traits.h. You
> could implement it as:
>
> template<typename _Tp>
> struct __is_arithmetic_t
> : public __truth_type<__is_arithmetic(_Tp)>
> { };
>
> François
>
Thank you for your review! This is from the type_traits header, so the
name should be as-is.
