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From: "ejtttje at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/50724] isnan broken by -ffinite-math-only in g++ Date: Fri, 14 Oct 2011 22:08:00 -0000 [thread overview] Message-ID: <bug-50724-4-p0dhsK1uwV@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-50724-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50724 --- Comment #11 from Ethan Tira-Thompson <ejtttje at gmail dot com> 2011-10-14 22:07:44 UTC --- Marc: is this code perusable? I'm curious because I expect either the calculations may generate NaN or not at all. If they might and you even have test cases to handle it, then I'm surprised you would ever want to support running with -ff-m-o. Conversely if you knew the code doesn't generate the nonfinite values, then you don't need the classifications in the first place...? I'm guessing (and apologies if this is inaccurate) that this might boil down to saying that you want to interpret an end user setting -ff-m-o as an opportunity to skip validating their input or skip doing assertions during its processing, which could be a reasonable thing to do, but that's a choice I'd rather leave to individual developers, e.g. can also wrap code with #if __FINITE_MATH_ONLY__==0 or such... Or in other words, it's only a missed optimization if you wind up with classification calls, whereas it's a full-fledged execution error when NaN gets past validation.
next prev parent reply other threads:[~2011-10-14 22:08 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-10-14 3:37 [Bug libstdc++/50724] New: " ejt at andrew dot cmu.edu 2011-10-14 9:17 ` [Bug libstdc++/50724] " rguenth at gcc dot gnu.org 2011-10-14 14:27 ` ejtttje at gmail dot com 2011-10-14 14:31 ` rguenth at gcc dot gnu.org 2011-10-14 14:49 ` redi at gcc dot gnu.org 2011-10-14 14:57 ` paolo.carlini at oracle dot com 2011-10-14 15:08 ` paolo.carlini at oracle dot com 2011-10-14 15:37 ` [Bug middle-end/50724] " matz at gcc dot gnu.org 2011-10-14 16:03 ` pinskia at gcc dot gnu.org 2011-10-14 20:08 ` ejtttje at gmail dot com 2011-10-14 21:13 ` marc.glisse at normalesup dot org 2011-10-14 22:08 ` ejtttje at gmail dot com [this message] 2011-10-15 8:52 ` rguenth at gcc dot gnu.org 2011-10-15 9:06 ` marc.glisse at normalesup dot org 2011-10-15 14:01 ` ejtttje at gmail dot com 2011-10-15 18:00 ` pinskia at gcc dot gnu.org 2011-10-16 10:00 ` rguenth at gcc dot gnu.org 2011-10-17 4:12 ` ejtttje at gmail dot com 2011-10-17 7:14 ` rguenth at gcc dot gnu.org 2011-10-17 15:31 ` [Bug libstdc++/50724] cmath's floating-point classification implementations inconsistent with math.h ejtttje at gmail dot com 2011-10-17 15:41 ` paolo.carlini at oracle dot com 2011-10-17 15:45 ` [Bug middle-end/50724] " paolo.carlini at oracle dot com 2011-10-17 16:47 ` ejtttje at gmail dot com 2011-10-17 16:50 ` paolo.carlini at oracle dot com 2011-10-17 18:38 ` ejtttje at gmail dot com 2011-10-17 18:54 ` paolo.carlini at oracle dot com 2011-10-17 19:22 ` ejtttje at gmail dot com 2011-10-17 19:26 ` pinskia at gcc dot gnu.org 2011-10-17 20:21 ` ejtttje at gmail dot com 2011-10-17 21:05 ` redi at gcc dot gnu.org 2011-10-17 21:22 ` redi at gcc dot gnu.org 2011-10-18 0:34 ` ejtttje at gmail dot com 2011-10-18 1:33 ` matz at gcc dot gnu.org 2011-10-18 9:42 ` redi at gcc dot gnu.org 2011-10-18 10:04 ` rguenth at gcc dot gnu.org 2011-10-18 21:09 ` ejtttje at gmail dot com 2021-09-21 1:12 ` egallager at gcc dot gnu.org
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