class SyntaxTree::YARV::SeaOfNodes::Compiler

def cleanup_phi_nodes

first place.
some mess we left. Ideally we wouldn't create these problems in the
We don't always build things in an optimal way. Go back and fix up 
def cleanup_phi_nodes
  nodes.dup.each do |node| # dup because we're mutating
    next unless node.is_a?(PhiNode)
    if node.inputs.size == 1
      # Remove phi nodes with a single input.
      connect_over(node)
      remove(node)
    elsif node.inputs.map(&:from).uniq.size == 1
      # Remove phi nodes where all inputs are the same.
      producer_edge = node.inputs.first
      consumer_edge = node.outputs.find { |e| !e.to.is_a?(MergeNode) }
      connect(
        producer_edge.from,
        consumer_edge.to,
        :data,
        consumer_edge.label
      )
      remove(node)
    end
  end
end