http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49365
Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2011.06.14 10:49:14 CC| |changpeng.fang at amd dot | |com Ever Confirmed|0 |1 --- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-14 10:49:14 UTC --- Indeed, for the important loop in StaggeredLeapfrog2.F we now have Ahead 1, unroll factor 1, trip count -1 insn count 919, mem ref count 100, prefetch count 100 Not prefetching -- instruction to prefetch ratio (9) too small while before the patch we had insn count 1019, mem ref count 100, prefetch count 100 as we now have half the cost for the vectorized mem-refs (100 instead of 200). Building with --param min-insn-to-prefetch-ratio=9 fixes it.