On Wed, 10 Jan 2024 at 19:41, Ken Matsui <kmat...@gcc.gnu.org> wrote:
>
> This patch optimizes the compilation performance of std::is_unsigned
> by dispatching to the new __is_unsigned built-in trait.
OK for trunk (if the new built-in is approved).
>
> libstdc++-v3/ChangeLog:
>
> * include/std/type_traits (is_unsigned): Use __is_unsigned
> built-in trait.
> (is_unsigned_v): Likewise.
>
> Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> ---
> libstdc++-v3/include/std/type_traits | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> index 6294f5af533..4bcfb1389e3 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -987,10 +987,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> { };
>
> /// is_unsigned
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__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
>
> /// @cond undocumented
> template<typename _Tp, typename _Up = _Tp&&>
> @@ -3413,8 +3420,14 @@ template <typename _Tp>
>
> template <typename _Tp>
> inline constexpr bool is_signed_v = is_signed<_Tp>::value;
> +
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_unsigned)
> +template <typename _Tp>
> + inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
> +#else
> template <typename _Tp>
> inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
> +#endif
>
> template <typename _Tp, typename... _Args>
> inline constexpr bool is_constructible_v = __is_constructible(_Tp,
> _Args...);
> --
> 2.43.0
>
