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

[Carlos O'Donell]

On 09/12/2014 01:33 AM, Andi Kleen wrote:
> Rich Felker <dalias@libc.org> writes:
>>
>> This really seems like something the compiler should be doing --
>> translating parallelizable calls to the standard math functions into
>> calls to special simd versions (
> 
> Of course gcc already supports that. Even in two different flavours.
> 
> Not sure why the patch doesn't implement one of those ABIs though.

Please note that AFAIK gcc doesn't implement the ABI as documented
by Intel, but a variant, and my expectation is that we should *absolutely*
be targetting the gcc version of the Intel ABI otherwise what's the point?

>      -mveclibabi=type
>            Specifies the ABI type to use for vectorizing intrinsics
>            using an external library.
>            Supported values for type are svml for the Intel short vector
>            math library and acml for
>            the AMD math core library.  To use this option, both
>            -ftree-vectorize and
>            -funsafe-math-optimizations have to be enabled, and an SVML
>            or ACML ABI-compatible
>            library must be specified at link time.

Cheers,
Carlos.