[Bug fortran/29383] Fortran 2003/F95[TR15580:1999]: Floating point exception (IEEE) support

["quantheory at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

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

Sean Santos <quantheory at gmail dot com> changed:

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                 CC|                            |quantheory at gmail dot com

--- Comment #10 from Sean Santos <quantheory at gmail dot com> 2012-12-04 19:28:19 UTC ---
Comment 9 seems a bit too pessimistic to me.

For one, returning ".false." for ieee_supports_* doesn't seem like a sidestep,
but more like the correct behavior in an environment that lacks IEEE support
(maybe even if the only reason is because the compiler has not implemented it).

For another, as noted above, one important use of the ieee_arithmetic module is
to test for NaN/Inf in a standard-conforming way, rather than using
compiler-specific extensions. (AFAIK, gfortran is the only F2003 compiler that
forces you to use a non-portable extension to do this.)

For that functionality, the only likely problem I can see is in deciding when
e.g. ieee_support_nan should return ".true.".

Of course this is only a fraction of what needs to be done (presumably the
easiest part), but it's much better than nothing, particularly to address what
I would expect to be one of the most common uses of this module.