(give-up-ir1-transform))
(let* ((denominator (lvar-value denominator))
(bits (1- (integer-length denominator))))
- (unless (= (ash 1 bits) denominator)
+ (unless (and (> denominator 0) (= (ash 1 bits) denominator))
(give-up-ir1-transform))
(let ((alignment (count-low-order-zeros numerator)))
(unless (>= alignment bits)