[PATCH 1/N] x86_64 vectorization support: vectorized math functions addition to Glibc

[Carlos O'Donell]

On 09/11/2014 04:57 PM, H.J. Lu wrote:
>> That doesn't answer my question.  Maybe glibc 2.21 provides such versions
>> for all x86 ISAs there are at present, up to AVX512 - and then a new
>> extension AVX1024 appears.  When GCC 7 is used with glibc 2.21 headers and
>> -mavx1024, it must not try to generate calls to the AVX1024 functions,
>> because glibc 2.21 doesn't have such functions.  But maybe glibc 2.26 adds
>> the AVX1024 functions.  So something needs to be different in the headers
>> of 2.26 to inform GCC 7 that AVX1024 versions of the functions are
>> available.  And I think that means the directive that communicates
>> function availability to the compiler needs to identify the set of ISAs
>> for which versions of the function in question are available.
>>
> 
> Wouldn't it be better to put libmvec in GCC instead?
 
That's certainly a discussion we can have.

What do you see as the pros and cons?

Cheers,
Carlos.