alias.c (component_uses_parent_alias_set): Rename from can_address_p.
* alias.c (component_uses_parent_alias_set): Rename from
can_address_p. Return bool. Reverse the sense of the result.
Reinstate the check for alias set zero.
(get_alias_set): Update to match.
* alias.h (component_uses_parent_alias_set): Likewise.
* emit-rtl.c (set_mem_attributes_minus_bitpos): Likewise.
* expr.c (expand_assignment): Likewise.
* expr.h: Remove commented out prototypes that were moved to alias.h.