Question 8056 – Compiler-Design

In Static Single Assignment form (SSA) each assignment to a variable should be specified with distinct names.
Generally, subscripts are used to distinguish each definition of variables.
In the given code segment, there are two assignments of the variable x
x = u – t;
x = y + w;
and three assignments of the variable y.
y = x * v;
y = t – z;
y = x * y
Hence, two variables viz x1, x2 should be used for specifying distinct assignments of x
and for y it is named as y1, y2 and y3 for each assignment of y.
Hence, total number of variables is 10 (x1, x2, y1, y2, y3, t, u, v, w, z), and there are 5 temporary variables.
Static Single Assignment form (SSA) of the given code segment is:
x1 = u – t;
y1 = x1 * v;
x2 = y1 + w;
y2 = t – z;
y3 = x2 * y2;