Aliasing violation generated by fold_builtin_memcmp?

[Richard Kenner]

    Uh, CAN_ALIAS_ALL seems like a very bad hack then.
    You should simply be creating a pointed-to type that aliases set 0, and
    using that for the pointed to type.
    That is, after all, what alias set 0 is for.

That's easy enough for integer types, but creating multiple record types
means duplicating lots of fields and layouts and is, in general, a mess.
What's special here is the pointer type, not the underlying type.