http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55194
--- Comment #3 from Joel Sherrill <joel at gcc dot gnu.org> 2012-11-04 06:22:22 UTC --- I added Jakub because I think this was the patch which broke it: Author: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Mon Aug 20 18:56:49 2012 +0000 PR rtl-optimization/54294 * fwprop.c (all_uses_available_at): Ignore debug insns in between def_insn and target_insn when checking whether the shortcut is possible.