[Bug tree-optimization/49365] 436.cactusADM performance regression

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49365

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-10 15:36:49 UTC ---
I'm trying to get my hands on it.  Most code differences betweeen good and
bad rev. appear in loop array prefetching.  Before aprefetch dumps differ only
for datestamp.c, PUGH/SetupPGV.c and regex.c.

I'm trying binaries with -fno-prefetch-loop-arrays now (well, on Monday
that is).

Prefetching uses tree_num_loop_insns which uses estimate_num_insns. 
Prefetching
is enabled by default for barcelona (but also for K8 where I don't see this
issue).  So my bet is on prefetching costs getting confused and need
adjustment.