A variable x is said to be live at a statement $${S_i}$$ in a programif the following three conditions hold simultaneously:

i. There exists a statement $${S_j}$$ that uses x
ii. There is a path from $${S_i}$$ to $${S_j}$$ in the flow graph corresponding to the program
iii. The path has no intervening assignment to x including at $${S_i}$$ and $${S_j}$$

The variables which are live both at the statement in basic block 2 and at the statement in basic block 3 of the above control flow graph are

The least number of temporary variables required to create a three-address code in static single assignment form for the expression $$q + r / 3 + s - t * 5 + u * v/w$$ is _______________.

For a C program accessing X[ i ] [ j ] [ k ], the following intermediate code is generated by a compiler. Assume that the size of an integer is 32 bits and the size of a character is 8 bits.

t0 = i * 1024 
t1 = j * 32 
t2 = k * 4 
t3 = t1 + t0 
t4 = t3 + t2 
t5 = X[t4] 

Which one of the following statements about the source code for the C program is CORRECT?

Consider the following translation scheme.

$$\eqalign{ & S \to ER \cr & R \to *E\left\{ {pr{\mathop{\rm int}} ('*');} \right\}R\,|\,\varepsilon \cr & E \to F + E\left\{ {pr{\mathop{\rm int}} (' + ');} \right\}\,|\,F \cr & F \to S\,|\,id\,\left\{ {pr{\mathop{\rm int}} (id.value);} \right\} \cr} $$

Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input '2 * 3 + 4' this translation scheme prints