https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90883
--- Comment #19 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- Surely the real problem is that the expansion doesn't really understand about the 'don't care' location and that we can therefore put any value in that? That additional knowledge would allow the earlier passes of the compiler to rewrite this as a simple store of zero to then entire object.
