Preparing precedence graph from fork and join code
x=2;
y=2;
z=2;

p1;

Fork L1  ; start p2

Fork L2 ; start p3

goto L3 ; stat P4

L1: p2;

fork L3 ;start p4;

goto L5


L3: join (x)

P4;

L4:  join(y)

s6;

Quit();

L2 : P3;

L5:  join(y)

 P5;  

 goto L4