http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49485
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-10-20 07:57:10 UTC --- BTW, 4.6 numbers can be improved to the trunk numbers by applying http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=179460 (aka a subset of Eric's r179165 change) - C++ references here prevent the vectorization of one of the loops.