diff options
Diffstat (limited to 'gcc/range-op.cc')
| -rw-r--r-- | gcc/range-op.cc | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/gcc/range-op.cc b/gcc/range-op.cc index 5e94c3d..a13e888 100644 --- a/gcc/range-op.cc +++ b/gcc/range-op.cc @@ -1911,8 +1911,20 @@ operator_mult::wi_fold (irange &r, tree type, // diff = max - min prod2 = prod3 - prod0; if (wi::geu_p (prod2, sizem1)) - // The range covers all values. - r.set_varying (type); + { + // Multiplying by X, where X is a power of 2 is [0,0][X,+INF]. + if (TYPE_UNSIGNED (type) && rh_lb == rh_ub + && wi::exact_log2 (rh_lb) != -1 && prec > 1) + { + r.set (type, rh_lb, wi::max_value (prec, sign)); + int_range<2> zero; + zero.set_zero (type); + r.union_ (zero); + } + else + // The range covers all values. + r.set_varying (type); + } else { wide_int new_lb = wide_int::from (prod0, prec, sign); @@ -1953,7 +1965,9 @@ operator_div::fold_range (irange &r, tree type, return true; tree t; - if (rh.singleton_p (&t)) + if (code == TRUNC_DIV_EXPR + && rh.singleton_p (&t) + && !wi::neg_p (lh.lower_bound ())) { wide_int wi = wi::to_wide (t); int shift = wi::exact_log2 (wi); |