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

[Tulio Magno Quites Machado Filho]

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.

Thank you!

-- 
Tulio Magno