[PATCH] libm -- fix expl kernels

[Steve Kargl]

On Sat, Sep 19, 2020 at 04:58:49PM -0700, Steve Kargl wrote:
> The following patch fixes the ld80 and ld128 kernels for expl(x).

Subj: is slightly wrong.  This fixes the cexpl(z) kernels.

> I can't test ld128, so that patch is untested.
> 
> . Micro-optimization: use sincosl(x) instead of a call to cosl(x) and
>   a call to sinl(x).  Argument reduction is done once not twice.

    This part also fixes a cos(x) that should be cosl(x).

> . Use a long double constant instead of an invalid double constant.
> . Spell scale2 correctly

-- 
Steve