On Tue, Nov 12, 2019 at 09:10:58AM +0100, Richard Biener wrote:
> On Tue, Nov 12, 2019 at 5:54 AM Jason Merrill <ja...@redhat.com> wrote:
> >
> > I'm not sure what semantics we might eventually want for vector <=>, but
> > let's
> > give a sorry for now.
>
> Given our vector extension does elementwise comparisons I don't think we can
> implement <=> in a reasonable manner.
Why? We indeed can't return a vector of std::strong_ordering or
std::partial_ordering classes, but we could return a vector of either the
underlying integral values (0/1/-1/-127), or vector of enums from which one
could construct those std::strong_ordering or std::partial_ordering classes.
We do not support vectors of pointers and so the only possibilities are
strong orderings for integral vectors and partial orderings for floating
point vectors.
Jakub
