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

Consider the intermediate code given below.

(1)  i = 1
(2)  j = 1
(3)  t1 = 5 ∗ i
(4)  t2 = t1 + j
(5)  t3 = 4 ∗ t2
(6)  t4 = t3
(7)  a[t4] = -1
(8)  j = j + 1
(9)  if j<=5 goto (3)
(10) i=i+1
(11) if i<5 goto (2)

The number of nodes and edges in the control-flow-graph constructed for the above code, respectively, are

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 C code segment.

for (i = 0; i < n; i++) 
  { 
      for (j=0; j < n; j++) 
      { 
          if (i%2) 
          { 
           x += (4*j + 5*i); 
           y += (7 + 4*j); 
          } 
       } 
  } 

Which one of the following is false?