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From: "nathanael.schaeffer at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/60237] isnan fails with -ffast-math
Date: Mon, 17 Feb 2014 11:16:00 -0000	[thread overview]
Message-ID: <bug-60237-4-X7RBPdxUpl@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-60237-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60237

--- Comment #2 from N Schaeffer <nathanael.schaeffer at gmail dot com> ---
Thank you for your answer.

My program (which is a computational fluid dynamics solver) is not supposed to
produce NaNs. However, when it does (which means something went wrong), I would
like to abort the program and return an error instead of continuing crunching
NaNs.
I also want it to run as fast as possible (hence the -ffast-math option).

I would argue that: if printf("%f",x) outputs "NaN", isnan(x) should also be
returning true.

Do you have a suggestion concerning my last question:
How can I check if x is NaN in a portable way (not presuming any compilation
option) ?


  parent reply	other threads:[~2014-02-17 11:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-17 10:41 [Bug c++/60237] New: " nathanael.schaeffer at gmail dot com
2014-02-17 10:53 ` [Bug c++/60237] " jakub at gcc dot gnu.org
2014-02-17 11:16 ` nathanael.schaeffer at gmail dot com [this message]
2014-02-17 11:26 ` glisse at gcc dot gnu.org
2014-02-17 11:38 ` nathanael.schaeffer at gmail dot com
2014-02-17 12:46 ` rguenth at gcc dot gnu.org
2014-02-17 16:16 ` nathanael.schaeffer at gmail dot com
2014-02-17 17:28 ` glisse at gcc dot gnu.org

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