[Bug fortran/32391] Generate wrong optimization code from fortran 77

["sunjoong at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from sunjoong at gmail dot com  2007-06-18 15:08 -------
Thank you, Tobias

I had missunderstood the default optimization level for gfortran
but the issue exists, I think.

I had traced side effects of optimization levels for the legacy program;
    -O0 level and -O1 level were different
    but from -O1 to -O3 gave same (wrong) results on gfortran, g77 and g95.
    I tested it with pgi fortran and got same (right) results.

I checked gfortran 4.0.4, 4.1.2 and 4.2.0.
I did not check gfortran 4.3.

2007/6/18, Tobias Burnus <burnus@net-b.de>:
> Sunjoong Lee wrote:
> > I had compiled a legacy fortran77 code and foud a bug;
> >    $ gfortran -o TMalign TMalign.f
> >    $ ./TMalign 1aquA.pdb 1avaC.pdb | grep ^Ali
> >    Aligned length=  89, RMSD=  6.41, TM-score= 0.24257, ID=0.042
> >    $ gfortran -O0 -o TMalign TMalign.f
> >    $ ./TMalign 1aquA.pdb 1avaC.pdb | grep ^Ali
> >    Aligned length=  91, RMSD=  6.35, TM-score=0.24762 , ID=0.024
> I find this difference very odd as "-O0" is the default optimization for
> gfortran. Other than that I get always the same result  ("91") with all
> -O levels I tried with gfortran 4.3, 4.2.0, 4.1.3 and ifort.
> 
> Which version of the compiler are you using on which platform. (Use
> "gfortran -v" to shows this information.)
> Can you also show what "alias gfortran" (or "type gfortran") shows? Just
> to make sure there is no alias which adds options.
> 
> Tobias
> 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32391