[PATCH 06/14] libstdc++: Optimize std::is_arithmetic compilation performance

[Jonathan Wakely]

On Wed, 10 Jan 2024 at 19:47, Ken Matsui <kmatsui@gcc.gnu.org> wrote:
>
> This patch optimizes the compilation performance of std::is_arithmetic
> by dispatching to the new __is_arithmetic built-in trait.

OK for trunk (if the new built-in is approved).


>
> libstdc++-v3/ChangeLog:
>
>         * include/std/type_traits (is_arithmetic): Use __is_arithmetic
>         built-in trait.
>         (is_arithmetic_v): Likewise.
>
> Signed-off-by: Ken Matsui <kmatsui@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 23ea70eca18..9baf3b2aa46 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -728,10 +728,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>  #endif
>
>    /// is_arithmetic
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__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>
> @@ -3317,8 +3324,14 @@ template <typename _Tp>
>    inline constexpr bool is_reference_v<_Tp&&> = true;
>  #endif
>
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__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;
>
> --
> 2.43.0
>