// Don't use for powers of 2.
	return d&(d-1) != 0
}

func udivisibleOK8(c int8) bool   { return udivisibleOK(8, int64(c)) }
func udivisibleOK16(c int16) bool { return udivisibleOK(16, int64(c)) }
func udivisibleOK32(c int32) bool { return udivisibleOK(32, int64(c)) }
func udivisibleOK64(c int64) bool { return udivisibleOK(64, c) }

type udivisibleData struct {
	k   int64  // trailingZeros(c)