[Bug fortran/51418] Fortran format sp,f0.0 output wrong with NaN and 0.0

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51418

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-12-05 08:40:49 UTC ---
(In reply to comment #0)
> This 6-line program prints " NaN" when IMHO it should print "NaN" and "+."
> when IMHO it should print "+0."
> gcc version 4.4.4 20100726 (Red Hat 4.4.4-13) (GCC) 
> gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)

With GCC 4.7 and 4.6.2, I get:
"NaN"
"+0."

However, with GCC 4.5.3 20110428, I get:
" NaN"
"**"

Thus, it must have been fixed in 4.6 - either 4.6.0 or later. I saw some
I/O-format-related changes around 2011-04-29 and some others around 2011-02-28.


As it is no regression, an (inconvenient but) minor issue, and as I/O format
fixes tend to have unexpected side effects, I do not think that the patches
will be back ported to 4.5 or even 4.4.


Thus, if the bug is a show stopper, you could try to install (possibly parallel
to 4.4) a newer GCC/gfortran. For instance, Fedora 16 ships with GCC 4.6 and
Ubuntu offers it as personal builds (cf.
http://gcc.gnu.org/wiki/GFortranDistros). There is also a gfortran developer
build for i386-linux at http://gcc.gnu.org/wiki/GFortranBinaries, which you
could use - or you build GCC yourself.

If it is no show stopper, you could also simply wait for the next Ubuntu
version or - for RHEL - for a 6.x version with a newer GCC as technical
preview.

Thanks for reporting the bug!