From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: Jeff Johnston <jjohnstn@redhat.com>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>,
Newlib <newlib@sourceware.org>
Subject: Re: incorrectly rounded square root
Date: Sun, 13 Jun 2021 00:31:32 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.2106130024510.61948@angie.orcam.me.uk> (raw)
In-Reply-To: <CAOox84vMKMnqi1uGyO8tBO+5mjmnq_oAxqsqogCBz0c9Q--Rbw@mail.gmail.com>
On Fri, 4 Jun 2021, Jeff Johnston wrote:
> The compiler is optimizing out the rounding check in ef_sqrt.c, probably
> due to the operation using two constants.
Have you checked the `-frounding-math' option to GCC? This piece of code
(as probably all newlib's math pieces) ought to be built with that option,
and if that still does not help (which it may well, as noted in the GCC
manual), then would you please file a bug with GCC, attaching the test
case discussed here as a reproducer?
FWIW glibc does use said option, which may be why seemingly equivalent
code works with glibc but not with newlib.
HTH,
Maciej
next prev parent reply other threads:[~2021-06-12 22:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-04 8:08 Paul Zimmermann
2021-05-31 20:52 ` Jeff Johnston
2021-06-01 7:11 ` Paul Zimmermann
2021-06-01 16:28 ` Jeff Johnston
2021-06-02 7:51 ` Paul Zimmermann
2021-06-02 13:07 ` Joel Sherrill
2021-06-02 18:43 ` Jeff Johnston
2021-06-02 19:07 ` Marco Atzeri
2021-06-02 19:12 ` Joel Sherrill
2021-06-03 3:01 ` Jeff Johnston
2021-06-03 10:21 ` Paul Zimmermann
2021-06-03 15:50 ` Jeff Johnston
2021-06-04 7:14 ` Paul Zimmermann
2021-06-04 18:44 ` Jeff Johnston
2021-06-04 18:59 ` Joel Sherrill
2021-06-05 13:25 ` Brian Inglis
2021-06-07 9:51 ` Paul Zimmermann
2021-06-12 22:31 ` Maciej W. Rozycki [this message]
2021-06-03 11:25 ` Paul Zimmermann
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