http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54735
--- Comment #8 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-10-02 10:37:08 UTC --- It seems that SSA form is not up-to-date: > ./cc1plus -quiet t.ii -O2 t.ii: In function 'void check_() [with NT = M; int s = 3]': t.ii:163:16: error: no immediate_use list check_() ^ for SSA_NAME: .MEM_62 in statement: # VUSE <.MEM_62> __assert_fail (0); t.ii:163:16: internal compiler error: verify_ssa failed which is after PRE. So it might be the reduced testcase is not triggering the same bug as the original one. Tackling the PRE bug now (thus, -fno-tree-pre fixes it).