http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51136
--- Comment #1 from vries at gcc dot gnu.org 2011-11-15 14:00:44 UTC --- Created attachment 25827 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25827 tentative patch The problem is that in update_vuses, we're removing the def of the def-use-chain we're walking with FOR_EACH_IMM_USE_STMT/FOR_EACH_IMM_USE_ON_STMT. Postponing the removal till after we've walked all the uses fixes the problem.