message: Add test for atomic fences
diff: -use std::sync::atomic::{AtomicBool, AtomicIsize, AtomicU64, Ordering::*};
  +use std::sync::atomic::{fence, AtomicBool, AtomicIsize, AtomicU64, Ordering::*};
  fn main() {
  atomic_bool();
  atomic_isize();
  atomic_u64();
  + atomic_fences();
  }
  fn atomic_bool() {
  @@ -57,6 +58,15 @@ fn atomic_u64() {
  ATOMIC.store(1, SeqCst);
  assert_eq!(ATOMIC.compare_exchange(0, 0x100, AcqRel, Acquire), Err(1));
  - assert_eq!(ATOMIC.compare_exchange_weak(1, 0x100, AcqRel, Acquire), Ok(1));
  + assert_eq!(
  + ATOMIC.compare_exchange_weak(1, 0x100, AcqRel, Acquire),
  + Ok(1)
  + );
  assert_eq!(ATOMIC.load(Relaxed), 0x100);
  }
  +
  +fn atomic_fences() {
  + fence(SeqCst);
  + fence(Release);
  + fence(Acquire);
  +}
  