http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44194
--- Comment #44 from Chip Salzenberg <chip at pobox dot com> 2012-09-12 23:21:21 UTC --- Note that the x86 target has been changed in svn to use TImode for 128-bit structures, and structures bigger than 128 bits may not be passed in registers, so triggering this bug may be quite different now.