Re: [PATCH 12/28] math: Use wordsize-64 version for isnan

["Gabriel F. T. Gomes" <gabriel@inconstante.eti.br>]

Hi, Adhemerval, Wilco,

On Wed, Jun 12 2019, Wilco Dijkstra wrote:
> 
> > My take is math wordsize-64 was added to overcome some old compiler 
> > deficiencies which most likely does not show any gain nowadays. Also,
> > specifically for isnan/isinf/isfinite I think multiple possible
> > optimization is a bit of over-engineering since the libc symbols will
> > be called with recent compiler only in very specific situations (most
> > likely not performance-wise).
> 
> Yes we shouldn't worry about old compilers. There is no reason for so
> many duplicated implementations. Given modern compilers inline isinf etc,
> trying to save 1 instruction in GLIBC versions makes no sense.

Makes sense.

> > What I would like to do is just uses wordsize-64 implementations as
> > default one and aim to provide specialized WORDSIZE paths if it really
> > provides a real gain.
> 
> Yes that is the best way forward. We should focus optimizations on
> areas where there is clear evidence of significant gains.
> 
> > So for this specific usage, isnan/isinf/isfinite, do you agree we can
> > just use wordsize-64 as default?
> 
> Absolutely.

Agreed.

Thank you both for all the clarification about 32-bits targets and
optimization focus.