https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106187
--- Comment #35 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- > There's no union involved here though but a memcpy used in BitCast. Agreed, but by creating a shared stack slot, the compiler is effectively creating a union of its own, and I think that needs to be accounted for. update_alias_info_with_stack_vars handles the cases where we have pointers (at the gimple level) into a shared stack slot, but doesn't (AFAICT) cater for RTL lowering creating additional pointers (as it must since all objects on the stack ultimately have to be addressed). So if we create a shared stack slot for objects of different types, why do we not also create an alias set for the combination of such types, much as we would do for a union?
