[PATCH] powerpc: add libmvec implementations of log and logf

[Shawn Landden]

On Thu, May 9, 2019 at 2:58 PM Tulio Magno Quites Machado Filho
<tuliom@ascii.art.br> wrote:
>
> Shawn Landden <shawn@git.icu> writes:
>
> > When I first looked at Bert's patch I saw all the scalar code for the
> > special path and thought it wasn't a real vector implementation.
> > Otherwise I wouldn't have tried to compete with him.
> >
> > HOWEVER, once I fixed the bugs in my benchmark programs, there is no
> > performance advantage of doing either log or logf with vector
> > operation, at least on this power 9 VPS---either mine or Bert's
> > patches. I think this is because they require too many table lookups
> > for the constants, and Power ISA 3.0 lacks both a gather instruction,
> > and a permutexvar instruction, both of which could be used to
> > vectorize these table lookups. (shufflevector can't do it)
>
> Base on this information and considering that you haven't a FSF copyright
> assignment, which means I can't look at your patch, I plan to merge Bert's
> patches.
How do I do the assignment? The web site only provided guidance for
what forms to send me, not how to do it myself.

Also, did you read that I could not find a performance improvement in
Bert's patches?
>
> Thank you!
>
> --
> Tulio Magno