http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52054
--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-11 09:34:40 UTC --- PR53125 has a testcase where we spend time in redundant store removal in eliminate() which does vn_reference_lookup with VN_WALK (which it should not need).