g77, g95, optimization

[Terry Frankcombe]

An aside...

On Mon, 2007-06-18 at 14:10 -0700, Steve Kargl wrote:
> > 3) I have a PC with an Intel Core 2 Duo E6700 CPU which runs at 2.66
> > Ghz.
> 
> With gfortran, try "-march=native -O3 -ffast-math -ftree-vectorize
> -funroll-loops"  I don't normally recommend -ffast-math, but you
> asked for the fastest execution (without specifying if you wanted
> correct results. :-)

I humbly submit Steve's email as evidence for my assertion that
gfortran/gcc dislikes simple flags to obtain simple results.  -fast,
anyone?  ;-)

<http://gcc.gnu.org/ml/fortran/2007-05/msg00301.html>
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31114>

...and now Tobias has given another, different(!) long set of flags...