https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97474
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #10)
> I think the place in the C++ FE that adds restrict here is:
> tree
> type_passed_as (tree type)
> {
> /* Pass classes with copy ctors by invisible reference. */
> if (TREE_ADDRESSABLE (type))
> {
> type = build_reference_type (type);
> /* There are no other pointers to this temporary. */
> type = cp_build_qualified_type (type, TYPE_QUAL_RESTRICT);
> }
>
> So, the options are either not to do it for types that contain any
> pointers/references among its members, or do some extra analysis as to
> whether even if it contains some pointers/references if those are guaranteed
> not to point to anything within the structure (e.g. because of TBAA rules),
> or using that analysis decide if it can use normal restrict or needs to use
> a weaker restrict, etc.
E.g. the vtable pointer is guaranteed not to point into the structure, so that
one can be special cased in the checking.
