% -*- mode: latex; auto-revert-interval: 0.5 -*-

\begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto, node distance=4em,
                   very thin,font={\scriptsize\bf}]

  \pgfdeclarelayer{background}
  \pgfdeclarelayer{foreground}
  \pgfsetlayers{background,main,foreground}

  \tikzstyle{basic-block} = [draw=black!50, fill=white, rectangle, minimum width=8.5em]
  \ifthenelse{\boolean{preview}}
    {\tikzstyle{block} = [basic-block]}
    {\tikzstyle{block} = [basic-block, drop shadow]}

  \tikzstyle{enter} = [block, ellipse, fill=red!20]
  \tikzstyle{guard} = [block, fill=yellow!20]
  \tikzstyle{newguard} = [block, fill=green!20]
  \tikzstyle{lbl} = [font={\scriptsize\it}, minimum width=0em]

  % \newboolean{loop-tree-step2}
  % \setboolean{loop-tree-step2}{false}

  \ifthenelse{\boolean{loop-tree-step2}} {
    \clip (-2.8, 2.1) rectangle (6.8,-6.9); 
  } {
    \clip (-2.8, 2.0) rectangle (1.9,-6.8); 
  }

  % plain nodes
  \node[enter, name=start] {loop($i_0$, $a_0$)} ;
  \node[guard, name=block1, below of=start] {
    \begin{tabular}{c} 
      $t_0$ = int\_mod($i_0$, $2$) \\
      $t_1$ = int\_is\_true($t_0$) \\
      \ifthenelse{\boolean{loop-tree-step2}} {
        guard\_true($t_1$)
      } {
        \textcolor{blue}{guard\_true($t_1$)}
      } \\
    \end{tabular}
  };

  \node[guard, name=block2, below of=block1, node distance=5em] {
    \begin{tabular}{c} 
      $a_1$ = int\_mul($a_0$, $2$) \\
      $i_1$ = int\_add($i_0$, $1$) \\
      $t_2$ = int\_lt($i_1$, $100$) \\
      guard\_true($t_2$) \\
    \end{tabular}
  };

  \node[guard, name=block3, below of=block2] { jump($i_1$, $a_1$) };
  
  \path (start.south) edge (block1.north) ;
  \path (block1.south) edge (block2.north) ;
  \path (block2.south) edge (block3.north) ;
  \path (block3.south) edge[distance=17em, out=230, in=110] (start.north) ;

  \ifthenelse{\boolean{loop-tree-step2}} {
    \node[newguard, name=block4, right=1em of block2] {
      \begin{tabular}{c} 
        $a_3$ = int\_add($a_2$, $1$) \\
        $i_3$ = int\_add($i_2$, $1$) \\
        $t_3$ = int\_lt($i_3$, $100$) \\
        guard\_true($t_3$) \\
      \end{tabular}
    };

    \node[newguard, name=block5, below of=block4] { jump($i_3$, $a_3$) };

    \path (block1.south east)  
              edge
              node[lbl] { 
                \begin{tabular}{c}
                    $i_2 \leftarrow i_0$ \\ 
                    $a_2 \leftarrow a_0$ \\
                \end{tabular}
                }
          (block4.north) ;

    \path (block4.south) edge (block5.north) ;
    \path (block5.south) 
              edge[out distance=22em, in distance=18em, out=320, in=70] 
          (start.north) ;
  }
  {}

    
\end{tikzpicture}