[PATCH] libstdc++: simd: allow x86 -mlong-double-64

[Alexandre Oliva]

On Mar 25, 2026, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:

> On Tue, 24 Mar 2026 at 06:30, Alexandre Oliva <oliva@adacore.com> wrote:
>>  template <typename _Tp, size_t _Bytes>
>>    struct __intrinsic_type<_Tp, _Bytes, enable_if_t<__is_vectorizable_v<_Tp> && _Bytes <= 64>>
>>    {
>> -    static_assert(!is_same_v<_Tp, long double>,
>> +    // allow _Tp == long double with -mlong-double-64
>> +    static_assert(!(is_same_v<_Tp, long double>
>> +                   && sizeof(long double) > sizeof(double)),
>> "no __intrinsic_type support for long double on x86");

> Would this be a little easier to understand as:

> if constexpr (sizeof(long double) > sizeof(double))
>   static_assert(!is_same_v<_Tp, long double>, "...");

It would be nicer indeed, but...
we can't do that in class scope, can we?

-- 
Alexandre Oliva, happy hacker            https://blog.lx.oliva.nom.br/
Free Software Activist     FSFLA co-founder     GNU Toolchain Engineer
More tolerance and less prejudice are key for inclusion and diversity.
Excluding neuro-others for not behaving ""normal"" is *not* inclusive!