digraph ssa {
    graph [dpi=300];
    rankdir=LR;

    "x1" [shape=diamond,label=<x<sub>1</sub>>];
    "x2" [shape=diamond,label=<x<sub>2</sub>>];
    "x3" [shape=diamond,label=<x<sub>3</sub>>];
    "return x" [label=<return <u>x</u>>];

    "0" -> "x1";
    "p.f" -> "x2";
    "x1" -> "x3";
    "x2" -> "x3";
    "x3" -> "return x";
}