http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51315
--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-12-06 14:16:21 UTC --- Note that in the end it's always us transforming a->b.c to (effectively) T *tem = &a->b.c; *tem which expand unfortunately handles differently. So whenever we do that we have to either avoid doing that if expand would have a different idea about the results alignment (there is currently no way that computes just expands idea of an expressions alignment - one piece of a good solution would provide that, not only SRA has this "issue"), or, stick that information somewhere (on the TREE_TYPE of the MEM_REF tree, but then it will only be honoured if the target provides a movmisalign optab - the other piece of a good solution would be that expand _always_ honors such alignment information and goes the same way as when expanding component refs).
