[PATCH] powerpc: Add a POWER8-optimized version of powf()

[Steven Munroe]

On Fri, 2017-05-26 at 16:55 -0300, Adhemerval Zanella wrote:
> 
> On 25/05/2017 14:47, Paul Clarke wrote:
> > This implementation is heavily based on sysdeps/ieee754/flt-32/e_powf.c.
> > Most significant changes are code simplification and use of doubles for
> > intermediate values.  Also, some rearrangement to move early
> > non-dependent code later, out of the faster paths.
> > 
> > 2017-05-25  Paul A. Clarke  <pc@us.ibm.com>
> > 
> > 	* sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
> > 	[$(subdir) = math] (libm-sysdep_routines): Add e_powf-power8 and
> > 	e_powf-ppc64.
> > 	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_powf-power8.c: New file.
> > 	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_powf-ppc64.c: Likewise.
> > 	* sysdeps/powerpc/powerpc64/fpu/multiarch/e_powf.c: Likewise.
> > 	* sysdeps/powerpc/powerpc64/power8/fpu/e_powf.c: Likewise.
> 
> This changes seems to be arch independent and I would like to avoid adding
> even more arch specific.  Is there any reason why this can't be used as
> the default implementation?  Do you have number on different architecture
> for it? 
> 
If other platform maintainer what to try this implementation and report
that would be OK. 

But I don't this it is correct or fair to ask Paul to prove a negative.
These quests tend to be very labor intensive and usually don't work out
(as really common) in the end.