https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88398
--- Comment #46 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Jiu Fu Guo from comment #45)
> (In reply to Wilco from comment #44)
> > (In reply to Jiu Fu Guo from comment #43)
> > > To handle vectorization for this kind of code, it needs to overcome the
> > > hard
> > > issue mentioned in comment #5: the loop has 2 exits.
> >
> > Yes and that also implies vector loads are unsafe unless they are
> > non-faulting. Few ISAs have such support.
>
> Since this is a loop, can we assume it is safe if reading data less than the
> upbound of the loop and if two buffers are not cross pages?
> something like: "while (++len != max - sizeof(T)) { T a = *(T*)(p+len)..}"
> and "p & page_size_mask == (p+len) & page_size_mask".
In other words, if the underlying buffers cover the low-bound and upbound of
the loop. We may assume it, but hard to prove it. In which circumstances, we
can prove it? Or does it make sense to provide a flag to let user confirm it
is safe?
