if !queued.contains(c.ID) {
					q = append(q, c)
					queued.add(c.ID)
				}
			}
		}
	}
}

// resolveFwdRefs links all FwdRef uses up to their nearest dominating definition.
func (s *phiState) resolveFwdRefs() {
	// Do a depth-first walk of the dominator tree, keeping track
	// of the most-recently-seen value for each variable.