This transforms

%a = shl nuw %x, c1 %b = icmp {ugt|ule} %a, c0

into

%b = icmp {ugt|ule} %x, (c0 >> c1)

z3:

(declare-const x (_ BitVec 64)) (declare-const c0 (_ BitVec 64)) (declare-const c1 (_ BitVec 64)) (push) (assert (= x (bvlshr (bvshl x c1) c1))) ; nuw (assert (not (= (bvugt (bvshl x c1) c0) (bvugt x (bvlshr c0 c1))))) (check-sat) (get-model) (pop) (push) (assert (= x (bvlshr (bvshl x c1) c1))) ; nuw (assert (not (= (bvule (bvshl x c1) c0) (bvule x (bvlshr c0 c1))))) (check-sat) (get-model) (pop)