[PATCH 08/14] libstdc++: Optimize std::is_compound compilation performance

[Jonathan Wakely]

On Wed, 10 Jan 2024 at 19:41, Ken Matsui <kmatsui@gcc.gnu.org> wrote:
>
> This patch optimizes the compilation performance of std::is_compound
> by dispatching to the new __is_arithmetic built-in trait.

OK for trunk (no need to wait for anything else to be approved).

>
> libstdc++-v3/ChangeLog:
>
>         * include/std/type_traits (is_compound): Do not use __not_.
>         (is_compound_v): Use is_fundamental_v instead.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
>  libstdc++-v3/include/std/type_traits | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> index 1c560d97e85..6294f5af533 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -784,7 +784,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    /// is_compound
>    template<typename _Tp>
>      struct is_compound
> -    : public __not_<is_fundamental<_Tp>>::type { };
> +    : public __bool_constant<!is_fundamental<_Tp>::value> { };
>
>    /// is_member_pointer
>  #if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
> @@ -3358,7 +3358,7 @@ template <typename _Tp>
>  template <typename _Tp>
>    inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
>  template <typename _Tp>
> -  inline constexpr bool is_compound_v = is_compound<_Tp>::value;
> +  inline constexpr bool is_compound_v = !is_fundamental_v<_Tp>;
>
>  #if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
>  template <typename _Tp>
> --
> 2.43.0
>