[PATCH 2/2] libstdc++: use new built-in trait __is_unsigned

[Jonathan Wakely]

On Tue, 21 Mar 2023 at 16:41, Ken Matsui via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:

> This patch lets libstdc++ use new built-in trait __is_unsigned.
>
> libstdc++-v3/ChangeLog:
>
>         * include/std/type_traits (is_unsigned): Use __is_unsigned
> built-in trait.
>

Please wrap the ChangeLog entry to less than 80 columns (including 8 for
the leading tab).



> ---
>  libstdc++-v3/include/std/type_traits | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> index 2bd607a8b8f..8d5a05cd0a6 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -884,10 +884,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      { };
>
>    /// is_unsigned
> +#if __has_builtin(__is_unsigned)
> +  template<typename _Tp>
> +    struct is_unsigned
> +    : public __bool_constant<__is_unsigned(_Tp)>
> +    { };
> +#else
>    template<typename _Tp>
>      struct is_unsigned
>      : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>::type
>      { };
> +#endif
>

Thanks, I expect this trait to make a much bigger difference than
add_const, so I'm very happy to see this one!



>
>    /// @cond undocumented
>    template<typename _Tp, typename _Up = _Tp&&>
> --
> 2.40.0
>
>