https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88332
--- Comment #10 from Segher Boessenkool <segher at gcc dot gnu.org> ---
You have
/* { dg-error "alignment of 's' is greater" "" { target pdp11*-*-* } } */
(the "" was added in r265741, the source tree I looked at wasn't up-to-date).
dg.exp says this is
# dg-error regexp comment [{ target/xfail selector } [{.|0|linenum}]]
so it should be fine now.
