interesting metric

[Jack Howarth]

Steve,
    Interesting, XL Fortran at -O3 produces exactly the same time as
gfortran at -O3 (121.8 seconds). At -O4, XL Fortrans is slightly 
faster (114.8 seconds), but only at -O5 does it break away (52.7 seconds).
The difference between -O4 and -O5 in XL Fortran is "-qipa=level=2"
which is...

                       Full interprocedural data flow and  alias
                        analysis.

Doesn't profiled IPA exist in gcc? I tried the following...

gfortran -O3 -fbranch-probabilities -fprofile-arcs -o mdyn mdyn.f90
./mdyn
gfortran -O3 -fbranch-probabilities -o mdyn mdyn.f90
./mydyn

...assuming that the first would profile using estimated probabilities
and then the second compile would use the actual measured values.
Unfortunately running the binary created from the second compile
produced no improvement.
           Jack