digraph g {
	Start [shape=box,label=<Start<br/>x = x_in>];
	End [shape=box,label=<End>];
	NE [label = <x_out = x<br/>Normal exit>];
	Start -> "if (x < 0)" -> "throw" -> "Error exit" -> End;
	"throw" -> "x = Math.sqrt(x)" [style=dashed];
	"if (x < 0)" -> "x = Math.sqrt(x)" -> NE -> End;
	// pdg
	f [label="f()",shape=rect];
	x_in [label = "x = x_in", style = dashed];
	x_out [label = "x = x_out", style = dashed];
	if [label = "if (x < 0)"];
	t [label = "throw"];
	ret [label = "x = Math.sqrt(x)"];
	ee [label = "error exit", style = dashed];
	ne [label = "normal exit", style = dashed];
	f -> x_in;
	f -> if -> t -> {ret ee ne};
	ne -> x_out;
	{ edge [color = red, constraint = false];
		x_in -> {if ret};
		ret -> x_out;
	}
}