Anti-dependence related bug in GCM

Ran into the following that was impacting BFS:

#[entry]
fn bug<n: usize>() -> i32[n] {
  let visited: bool[n];
  let cost: i32[n];

  for i = 0 to n {
    if visited[i] {
      cost[i] = cost[i] + 1;
    }
  }

  for i = 0 to n {
    visited[i] = true;
  }

  return cost;
}

The error occurs at the last execution of GCM, and reports

  thread 'main' panicked at hercules_ir/src/dom.rs:157:17:
  In DomChainIterator, top node (NodeID(40)) doesn't dominate bottom node (NodeID(1)).

Node 1 is the if of the first loop's guard while 40 is that loop's header.

The issue seems to be that GCM decides that the schedule_early of the read of visited in the first loop must is node 40 (inside the loop, this is correct) but that the schedule_late is Node 1 because it is computing the least common ancestors of its users (including anti-dependence users) and it has an anti-dependence user which is the write in the second loop and its actual user is the if inside the first loop, and their least common ancestor is Node 1.