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From: "quantheory at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/29383] Fortran 2003/F95[TR15580:1999]: Floating point exception (IEEE) support
Date: Sun, 14 Apr 2013 20:09:00 -0000	[thread overview]
Message-ID: <bug-29383-4-VU5vO6xN64@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-29383-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29383

--- Comment #11 from Sean Santos <quantheory at gmail dot com> 2013-04-14 20:08:59 UTC ---
I'm doing a bit of research because I'm considering trying to tackle part of
this soon.

I believe that the Fortran standard does not require the rounding mode to apply
to operations performed during constant folding, so point 4 above is moot.

Please see the collected interpretations of F2003:

http://j3-fortran.org/doc/standing/links/016.txt

Particularly see F03/0040 and F03/0078. In combination they guarantee that the
compiler is allowed to transform expressions at compile time according to the
"mathematical equivalence" rule regardless of the rounding mode. In any case,
the rounding mode cannot always be established at compile time; if the
committee had not decided upon this behavior, then constant folding would often
be impossible, period.

The Fortran 2003 and 2008 standards also give examples where constant folding
and propagation are allowed to influence whether or not an IEEE exception is
signaled.


  parent reply	other threads:[~2013-04-14 20:09 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-29383-4@http.gcc.gnu.org/bugzilla/>
2011-01-24  9:41 ` thenlich at users dot sourceforge.net
2011-07-22 17:55 ` longb at cray dot com
2012-10-07  0:09 ` kargl at gcc dot gnu.org
2012-10-09 15:19 ` andy.nelson at lanl dot gov
2012-10-09 17:01 ` kargl at gcc dot gnu.org
2012-12-04 19:28 ` quantheory at gmail dot com
2013-04-14 20:09 ` quantheory at gmail dot com [this message]
2014-01-06 11:33 ` janus at gcc dot gnu.org
2014-06-03 18:15 ` w6ws at earthlink dot net
2014-06-07 10:19 ` fxcoudert at gcc dot gnu.org
2014-06-07 10:19 ` fxcoudert at gcc dot gnu.org
2014-06-07 10:23 ` fxcoudert at gcc dot gnu.org
2014-06-07 10:25 ` fxcoudert at gcc dot gnu.org
2014-06-15 16:57 ` fxcoudert at gcc dot gnu.org
2014-06-28 14:18 ` fxcoudert at gcc dot gnu.org
2014-06-28 15:11 ` fxcoudert at gcc dot gnu.org
2022-09-10 13:43 ` vital.had at gmail dot com
2006-10-08  8:41 [Bug fortran/29383] New: " tobias dot burnus at physik dot fu-berlin dot de
2006-10-22  7:20 ` [Bug fortran/29383] " fxcoudert at gcc dot gnu dot org
2009-09-07  8:07 ` burnus at gcc dot gnu dot org
2010-04-14  6:33 ` burnus at gcc dot gnu dot org
2010-06-12 12:15 ` burnus at gcc dot gnu dot org

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