Question about building and using libmvec

[Szabolcs Nagy]

On 31/01/18 22:15, Carlos O'Donell wrote:
> On 01/31/2018 01:17 PM, Steve Ellcey wrote:
>> I have a libmvec question.  Should it be possible to build libmvec on any
>> platform or is it just on x86?  The only abilist I see for libmvec
...
> See:
> https://sourceware.org/ml/libc-alpha/2017-03/msg00333.html
> 

i was looking at adding vector math function implementations
to aarch64 (there is only x86_64 asm now, we could probably
add generic c dummy implementations which just fall back to
scalar code and add optimized asm later, this would allow
vectorizing some loops, but the math code would not be faster)

however we need a vector abi first (to get the mangled function
names and call abi right) this is not yet published, but in progress.

and we need gcc support (so simd attributes/omp pragmas are
enabled and if the vector function call convention is special
that should be implemented too).

another gcc issue that would be nice to fix is to make all
this work in fortran: currently the list of simd functions
are described in c headers so it does not affect fortran.
(there is no command line option to enable vectorization
of a particular function)

doing various benchmarks my impression is that improving
scalar math can give bigger benefit at this point so vector
math is lower priority for me now, but i'm still interested
in it, once the vector abi is finalized.