[Bug fortran/32391] Wrong code with optimization on i686-pc-linux-gnu

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

------- Comment #18 from sunjoong at gmail dot com  2007-06-21 03:27 -------
I appreciate kargl's comments; they were helpful.
I had known there is VOLATILE attribute in new Fortran standard
but I had worked with "LEGACY" fortran77 program!

I'll write C code if I shuld write one; that is more compatable for me.
However there are many legacy fortran 77 code in my field
and I don't want to rewrite it.

Small adjustment like '-ffloat-store'
when compiling by gfortran instead of pgf77
is acceptable
for I understood the behavior of register kargl told me.
(I had read Goldberg's briefly but that is not point.)

I had ONLY HOPEd VOLATILE statement in fortran 77 EXTENSION of gfortran.
I thought that would be convenient
on small modification of legacy fortran 77 program.

(In reply to comment #17)
> You need to update the Fortran Standard that you use.  Fortran
> 77 hasn't been the standard since about 1990.  In fact, you're
> 3 standard been!  There was Fortran 90, which was replaced by
> Fortran 95, which was replaced by Fortran 2003.  Fortran 2003 
> has the VOLATILE attribute and VOLATILE statement.  Guess what??
> No, go ahead and guess!  gfortran supports this feature.
> 
> You need to go read Goldberg's paper about floating point arithmetic.
> 


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