digraph Memory {
  rankdir=LR;
  node [shape=box];
  P [label="MemPhi(x)"];
  B [label="BulkMemPhi(All except x)"];
  Left -> P [label="slice x",color=blue]; Right -> P [label="slice x",color=blue];
  Left -> B; Right -> B;
  Region -> P [style=dashed]; Region -> B [style=dashed];
  P -> MemMerge [label="x",color=blue]; B -> MemMerge [label="default"];
}