digraph Memory {
  rankdir=RL;
  node [shape=box];
  P [label="Phi(memory)"];
  S [label="Loop-body Store"];
  P -> Entry [color=blue];
  P -> S [color=blue,constraint=false]; // Backedge must not place Store before Phi.
  S -> P [color=blue];
  P -> Loop [style=dashed]; Return -> P [color=blue];
  Return -> S [style=invis]; // Layout only: Phi, Store, Return from left to right.
}