On Tue, 8 Aug 2023 at 21:09, Jonathan Wakely <jwakely@redhat.com> wrote:

>
>
> On Sat, 15 Jul 2023 at 05:57, Ken Matsui via Libstdc++ <
> libstdc++@gcc.gnu.org> 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 <kmatsui@gcc.gnu.org>
>>
>
> OK for trunk (if the front-end changes are approved).
>

Oh, this is the v2 patch and there's a v4 ... but I think they're the same.



>
>
>
>
>> ---
>>  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>
>> --
>> 2.41.0
>>
>>