http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54622 --- Comment #2 from Janis Johnson <janis at gcc dot gnu.org> 2012-09-19 01:16:58 UTC --- Effective targets vect_unpack and vect_pack_trunc both require little endian for ARM, which is why I thought that perhaps some of the others do as well.