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From: "sgk at troutmask dot apl.washington.edu" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/48979] FRACTION und EXPONENT return invalid results for infinity/NaN Date: Thu, 12 May 2011 19:33:00 -0000 [thread overview] Message-ID: <bug-48979-4-1gCOm2xMoR@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-48979-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48979 --- Comment #5 from Steve Kargl <sgk at troutmask dot apl.washington.edu> 2011-05-12 18:47:54 UTC --- On Thu, May 12, 2011 at 05:59:44PM +0000, burnus at gcc dot gnu.org wrote: > > Whether this really is a bug or not depends on whether one thinks that a > > standard-compliant Fortran program should compile without requiring special > > options (I do). > > So do I - but the question is whether it is standard conforming. NAN and INF > are not Fortran numbers, cf. "13.4 Numeric models". Admittedly, IEEE and > Fortran model numbers are widely mixed in the standard. However, strictly > speaking, the IEEE functionality is only available if the relevant IEEE module > is loaded and the feature is marked as supported. > >From F2003: Page 300: A program is prohibited from invoking an intrinsic procedure under circumstances where a value to be returned in a subroutine argument or function result is outside the range of values representable by objects of the specified type and type parameters, unless the intrinsic module IEEE_ARITHMETIC (section 14) is accessible and there is support for an infinite or a NaN result, as appropriate. Page 364: The intrinsic modules IEEE_EXCEPTIONS, IEEE_ARITHMETIC, and IEEE_FEATURES provide support for exceptions and IEEE arithmetic. Whether the modules are provided is processor dependent. 1) Thomas's program does not USE IEEE_ARITHMETIC. 2) gfortran does not supply the ieee modules. So, calling fraction() with +-Inf and NaN is, I believe, technically non-conforming. I agree that having consistency between constant-folding and runtime results is desirable, I disagree on calling the need for -fno-range-check a bug.
next prev parent reply other threads:[~2011-05-12 19:20 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-05-12 15:27 [Bug fortran/48979] New: " thenlich at users dot sourceforge.net 2011-05-12 16:34 ` [Bug fortran/48979] " kargl at gcc dot gnu.org 2011-05-12 18:00 ` thenlich at users dot sourceforge.net 2011-05-12 18:04 ` burnus at gcc dot gnu.org 2011-05-12 18:37 ` sgk at troutmask dot apl.washington.edu 2011-05-12 19:33 ` sgk at troutmask dot apl.washington.edu [this message] 2011-05-12 19:45 ` sgk at troutmask dot apl.washington.edu 2011-05-12 20:32 ` sgk at troutmask dot apl.washington.edu 2011-05-12 21:07 ` burnus at gcc dot gnu.org 2011-05-12 21:11 ` sgk at troutmask dot apl.washington.edu 2011-05-12 21:12 ` sgk at troutmask dot apl.washington.edu 2011-05-13 9:28 ` thenlich at users dot sourceforge.net 2011-05-13 10:04 ` burnus at gcc dot gnu.org 2011-05-13 15:07 ` sgk at troutmask dot apl.washington.edu 2011-05-22 23:19 ` kargl at gcc dot gnu.org 2011-05-22 23:38 ` kargl at gcc dot gnu.org 2014-01-07 8:26 ` dominiq at lps dot ens.fr 2014-09-27 8:45 ` fxcoudert at gcc dot gnu.org 2014-10-11 16:58 ` fxcoudert at gcc dot gnu.org 2014-10-19 21:04 ` fxcoudert at gcc dot gnu.org
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