https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104334
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, I think one way is to punt on these small precision types, like:
--- range-op.cc.jj1 2022-01-13 22:29:15.345831749 +0100
+++ range-op.cc 2022-02-02 13:44:05.813637820 +0100
@@ -148,11 +148,13 @@ range_operator::wi_fold_in_parts (irange
int_range_max tmp;
wide_int rh_range = wi::sub (rh_ub, rh_lb, TYPE_SIGN (type), &ov_rh);
wide_int lh_range = wi::sub (lh_ub, lh_lb, TYPE_SIGN (type), &ov_lh);
- signop sign = TYPE_SIGN (type);;
+ signop sign = TYPE_SIGN (type);
// If there are 2, 3, or 4 values in the RH range, do them separately.
// Call wi_fold_in_parts to check the RH side.
- if (wi::gt_p (rh_range, 0, sign) && wi::lt_p (rh_range, 4, sign)
- && ov_rh == wi::OVF_NONE)
+ if (wi::min_precision (4, sign) <= wi::get_precision (rh_range)
+ && ov_rh == wi::OVF_NONE
+ && wi::gt_p (rh_range, 0, sign)
+ && wi::lt_p (rh_range, 4, sign))
{
wi_fold_in_parts (r, type, lh_lb, lh_ub, rh_lb, rh_lb);
if (wi::gt_p (rh_range, 1, sign))
@@ -170,8 +172,10 @@ range_operator::wi_fold_in_parts (irange
}
// Otherise check for 2, 3, or 4 values in the LH range and split them up.
// The RH side has been checked, so no recursion needed.
- else if (wi::gt_p (lh_range, 0, sign) && wi::lt_p (lh_range, 4, sign)
- && ov_lh == wi::OVF_NONE)
+ else if (wi::min_precision (4, sign) <= wi::get_precision (lh_range)
+ && ov_lh == wi::OVF_NONE
+ && wi::gt_p (lh_range, 0, sign)
+ && wi::lt_p (lh_range, 4, sign))
{
wi_fold (r, type, lh_lb, lh_lb, rh_lb, rh_ub);
if (wi::gt_p (lh_range, 1, sign))
i.e. only optimize if 4 is representable in the given wide_int.
The other option is to be extra careful.
