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From: Florian Weimer <fweimer@redhat.com>
To: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
 libc-alpha@sourceware.org
Subject: Re: fix inaccuracy of j0f for x >= 2^127 when sin(x)+cos(x) is tiny
 (v3)
References: <mwmu3knale.fsf@tomate.loria.fr>
 <alpine.DEB.2.21.2007272133330.13114@digraph.polyomino.org.uk>
 <mweeow9hg6.fsf@tomate.loria.fr> <87wo2oxahr.fsf@igel.home>
 <mw8sf3ap77.fsf@tomate.loria.fr>
 <fe0bebef-48f3-6cda-13cf-0037fb22796a@linaro.org>
 <mw4kpqx0ph.fsf@tomate.loria.fr>
 <b072854e-8e4e-831f-df6e-f63c481a1e5c@linaro.org>
 <mwy2n1tqof.fsf@tomate.loria.fr>
Date: Thu, 30 Jul 2020 10:53:24 +0200
In-Reply-To: <mwy2n1tqof.fsf@tomate.loria.fr> (Paul Zimmermann's message of
 "Thu, 30 Jul 2020 09:20:16 +0200")
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* Paul Zimmermann:

>        Dear Adhemerval,
>
> thank you again for your useful comments.
>
>> Does it require any ULP adjustment (at least on the architecture you
>> tested it)?
>
> I reset to 0 the j0/float values in sysdeps/x86_64/fpu/libm-test-ulps,
> then ran "make regen-ulps", and got:
>
> $ diff ../sysdeps/x86_64/fpu/libm-test-ulps /localdisk/zimmerma/glibc/build/math/NewUlps
> 1315c1315
> < float: 0
> ---
>> float: 8
> 1321c1321
> < float: 0
> ---
>> float: 4
> 1327c1327
> < float: 0
> ---
>> float: 5
> 1333c1333
> < float: 0
> ---
>> float: 5
>
> which were the original values except for j0_towardzero (it was 6).
> However the same applies to "master", so this is independent from my change.
> Anyway, I decreased the value from 6 to 5.

I suggest to leave it at 6, other CPU variants may still need the 6
there.

Thanks,
Florian