Hello!
There is an interesting comparison of SPEC scores between gcc and icc:
http://people.redhat.com/dnovillo/spec2000.i686/gcc/individual-run-ratio.html
. A quick look at the graphs shows a big differences in achieved scores
between gcc and icc, mostly in SpecFP tests. I was trying to find some
information on this matter, but none can be found in the archives on
gcc's site.
An interesting examples are:
-177.mesa (this is a c test), where icc is almost 40% faster
-178.galgel, where icc is again 40% faster
-179.art, where llvm is more than 1.5x faster than both gcc and icc
-187.facere, where icc is 100% faster than gcc
-189.lucas, where icc is 60% faster
I know that these graphs don't show the results of most aggresive
optimization options for gcc, but that is also the case with icc (only
-O2). However, it looks that gcc and icc are not even in the same class
regarding FP performance. Perhaps there is some critical optimizations,
that are not present in gcc?
I think I'm not the only person, that finds these results rather
"dissapointing". As Scott is currently writing a paper on gcc's FP
performance, perhaps someone has an explanation, why gcc's results are
so low on Pentium4 for these tests?
Uros.
