Optimizations

[Dave Love]

>>>>> "Marc" == Marc Lehmann <pcg@goof.com> writes:

 Marc> on x86, while -funroll-all-loops is generally a win! (even more
 Marc> so that -funroll-loops)

Could someone explain exactly what is the difference between the sort
of loops unrolled by -funroll-all-loops and -funroll-loops?  The doc
sentence isn't clear to me and ISTR that grovelling unroll.c wasn't
immediately enlightening.  Is it something like for(;;) versus
for(i=1;i<=n;i++)?

BTW, in case the original question fortran-related, at least for
fortran with the default (non-)aliasing model, -fforce-addr can be a
win on x86 as Toon has pointed out.  BTW2, the suggestions for [56]86
options with -malign-...=2 are propagated -- bother -- in the g77
manual, AFAIR after the Linux GCC-HOWTO.