https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112843
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> (In reply to Richard Biener from comment #2)
> > what?! Ick. It definitely shouldn't re-fold anything but only scrap caches
> > _at most_.
>
> So it does
>
> // Only update if it already had a value.
> if (m_cache.get_global_range (r, lhs))
> {
> // Re-calculate a new value using just cache values.
> Value_Range tmp (TREE_TYPE (lhs));
> fold_using_range f;
> fur_stmt src (s, &m_cache);
> f.fold_stmt (tmp, s, src, lhs);
>
> // Combine the new value with the old value to check for a change.
> if (r.intersect (tmp))
> {
> if (dump_file && (dump_flags & TDF_DETAILS))
> {
> print_generic_expr (dump_file, lhs, TDF_SLIM);
> fprintf (dump_file, " : global value re-evaluated to ");
> r.dump (dump_file);
> fputc ('\n', dump_file);
> }
> m_cache.set_global_range (lhs, r);
>
> WTF? If a pass invalidates a range it needs to properly do this itself.
> But update_stmt itself _never_ should alter range info.
At least the testcase that was added with it still passes when I remove
the call to get_range_query (fn)->update_stmt
