Huh...no argument from me.

Thanks.
Aldy

On Mon, Nov 14, 2022, 15:35 Jakub Jelinek <jakub@redhat.com> wrote:

> On Mon, Nov 14, 2022 at 07:30:18AM -0700, Jeff Law via Gcc-patches wrote:
> > To Jakub's concern.  I thought sqrt was treated like +-/* WRT accuracy
> > requirements by IEEE.   ie, for any input there is a well defined answer
> for
> > a confirming IEEE implementation.   In fact, getting to that .5ulp bound
> is
> > a significant amount of the  cost for a NR or Goldschmidt (or hybrid)
> > implementation if you've got a reasonable (say 12 or 14 bit) estimator
> and
> > high performance fmacs.
>
> That might be the case (except for the known libquadmath sqrtq case
> PR105101 which fortunately is not a builtin).
> But we'll need to ulps infrastructure for other functions anyway and
> it would be nice to write a short testcase first that will test
> sqrt{,f,l,f32,f64,f128} and can be easily adjusted to test other functions.
> I'll try to cook something up tomorrow.
>
>         Jakub
>
>