COMPILER CONSTRUCTION?BasicBlocks

Control Flow and Liveness Analysis. The following fragment of 3-address code was produced by a nonoptimizing compiler 1 start: sum0 2 3 test 4 switch: goto disp 5 case 1: sum=sum + 1 6 7 case2 : t1 = 1 8 9 if i> n goto end1 goto end2 t22 t1 sum-sum + t2 10 11 case3: t1sunm 12 13 14 15 default:sum - sum +1 16 17 18 disp:if i 5 goto case1 19 20 21 22 end2 : 1 1 + 1 23 24 end1 t2-t1 + 2 sum = t2 goto end2 goto end2 goto end2 if i -- 8 goto case2 if i 13 goto case3 goto default goto test print sum