B1
B2
B3
B4
Flow Graph over Blocks
4/43
sum := 0;
i := 0;
L1:
if i >= n goto L2;
  sum := sum + a[i];
  i := i + 1;
  goto L1;
L2:
result := sum
B1
B2
B3
B4
Program with basic blocks:
Flow control graph:
Note: Isolated blocks in a flow graph = dead code