[Bug fortran/48636] Enable more inlining with -O2 and higher

["hubicka at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48636

--- Comment #27 from Jan Hubicka <hubicka at gcc dot gnu.org> 2012-10-20 10:34:58 UTC ---
Thank you for testing. It seems that the patch works well for small benchmarks,
I will look into lapack/test_fpu slowdown.
There is problem that it really causes inacceptable growth on SPEC2k6 and 2k in
non-LTO mode.  I will need to analyze some of these testcases and see why we
predict so much of speedup when there are no benefits in runtime.

Jakub: the plan is to make ipa-cp to handle propagation across aggregates in
general (jump functions are already in place), that will handle the array
descriptors, too.

The fatigue is however different case - the values happens to be loop invariant
of the outer loop the function is called from. So inlining enables a lot of
invariant code motion.  This is similar to cray. Both these cases are now
understood by ipa-inline-analysis but the fact is not really used w/o this
patch.