Prova con questo:
`
\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\tikzstyle{decisione} = [diamond, draw, inner xsep=1em, inner ysep=1ex]
\tikzstyle{istruzione} = [rectangle, draw, inner xsep=2em, inner ysep=2ex]
\tikzstyle{stato} = [rectangle, draw, rounded corners=2ex, inner xsep=1.5em, inner ysep=1ex]
\begin{document}
\begin{tikzpicture}[node distance = 2cm, >=latex]
\node [stato] (A) {A};
\node [istruzione, below of=A] (value) {1234567889};
\node [decisione, below of=value] (test) {test};
\node [stato, below of=test] (D) {D};
\draw[->] (A) — (value);
\draw[->] (value) — (test);
\draw[->] (test) — (D);
\draw[->] (test) -| node [near start,above] {SI} +(-6em,0) |- (value);
\end{tikzpicture}
\end{document}`
(Comunque è bene non porre domande disparate in un unico thread.)
Ciao,
Antonio