On the page you linked panics are only mentioned for load and store and the code below seems to work just fine?

    let x = atomic::AtomicU32::new(0);
    x.compare_exchange_weak(
        0,
        1,
        atomic::Ordering::AcqRel,
        atomic::Ordering::Relaxed).unwrap();
    println!("{}", x.load(atomic::Ordering::Relaxed));