Effects of Pointers on Data Dependences(5)

Data dependences, which relate statements that compute data values to statements that use those values, are useful for automating a variety of program-comprehension-related activities, such as reverse engineering, impact analysis, and debugging. Unfortunat

1.2.3.4.5.6.7.8.9.10.11.

inti;main(){

int*p;

intj,sum1,sum2;sum1=0;sum2=0;readi,j;

while(i<10){

if(j<0){

p=&sum1;}

else{

p=&sum2;}

*p=add(j,*p);readj;}

sum1=add(j,sum1);printsum1,sum2;}

12.13.14.15.16.17.18.19.20.21.

intadd(intval,intsum){

int*q,k;readk;

if(sum>100){

i=9;}

sum=sum+i;if(i<k){

q=&val;}

else{

q=&k;}

sum=sum+*q;i=i+1;returnsum;}

Figure3:ProgramSum.

slicecanalsobecomputedintheforwarddirection:aforwardsliceincludesthosestatementsinPthatarein uenced

bythevaluesofthevariablesinVats.

2A