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

[Ken Matsui <kmatsui@cs.washington.edu>]

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I see. Thank you!


On Tue, Mar 21, 2023 at 9:44 AM Jonathan Wakely <jwakely@redhat.com> wrote:

>
>
> 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
>>
>>