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

[Wilco Dijkstra]

Hi Adhemerval,

> 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.

> 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.

Wilco