https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104334
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
> And another question is, the 2, 3, 4 cases handling seems like an
> optimization, > so wi_fold at line 192 should give the right answer, but it
> doesn't.
Actually no, I misunderstood, with -O0 or non-LTO, it is the wi_fold call,
while with LTO it is the
178 wi_fold (r, type, lh_lb, lh_lb, rh_lb, rh_ub);
179 if (wi::gt_p (lh_range, 1, sign))
180 {
181 wi_fold (tmp, type, lh_lb + 1, lh_lb + 1, rh_lb, rh_ub);
182 r.union_ (tmp);
183 if (wi::eq_p (lh_range, 3))
184 {
(gdb)
185 wi_fold (tmp, type, lh_lb + 2, lh_lb + 2, rh_lb, rh_ub);
186 r.union_ (tmp);
187 }
188 }
189 wi_fold (tmp, type, lh_ub, lh_ub, rh_lb, rh_ub);
190 r.union_ (tmp);
optimization. And that one doesn't work too well, because
wi::eq_p (lh_range, 3) is false:
xi.is_sign_extended is true, yi.is_sign_extended is true
lh_range.val[0] is -1, and yi.val[0] is 3, so it isn't equal.
That is because we haven't sign-extended 3.
