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Use when code uses a conditional branch to reset/clamp a counter (e.g., `if(cnt < 0){ fill++; cnt = 0; }`) that introduces an extra control-flow path on every loop iteration
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Use when printf statements output strings without trailing newlines
Use when array is accessed with direct user input as index (0-based indexing)
Use when the program accesses a precomputed table using an offset (e.g., arr[n-1]) that introduces an arithmetic operation between the symbolic input and the index
Use when loop variables iterate over character values (e.g., ASCII codes) to represent different operations or choices
Use when code uses a loop to search for an input value in an array and then uses the found index for further computation
Use when code reads a fixed number of characters into an array and only accesses individual elements
| name | avoid-branch-driven-counter-resets |
| description | Use when code uses a conditional branch to reset/clamp a counter (e.g., `if(cnt < 0){ fill++; cnt = 0; }`) that introduces an extra control-flow path on every loop iteration |
A KLEE-coverage code transformation. Applying it rewrites C source so symbolic execution explores more of the program's behavior.
When code uses a conditional branch to reset/clamp a counter (e.g., if(cnt < 0){ fill++; cnt = 0; }) that introduces an extra control-flow path on every loop iteration
Replace the reset-and-increment pattern with a running-minimum tracker (e.g., if(a < b) b = a;) and compute the needed prefix/suffix counts arithmetically from the min and final values, eliminating the per-iteration state-mutating branch
Each conditional reset doubles the symbolic path count per loop iteration, causing exponential path explosion in KLEE; tracking a min via a single comparison keeps the branch but avoids state divergence that compounds across iterations, allowing constraints to remain linear and solvable
Before:
#include <stdio.h>
char s[105];
int main(){
int N;
scanf("%d", &N);
scanf("%s", &s[1]);
int cnt = 0, fill = 0;
for(int i=1; i<=N; i++){
if(s[i] == '(') cnt++;
else cnt--;
if(cnt < 0){ fill++; cnt = 0; }
}
while(fill--) printf("(");
printf("%s", &s[1]);
while(cnt--) printf(")");
return 0;
}
After:
#include<stdio.h>
#define REP(i,n) for(int i = 0; i < (n); i++)
#define STRS(i,str) for(int i = 0; str[i]; i++)
int main(void){
char ch[120];
int dum;
int a = 0, b = 0;
scanf("%d%s", &dum, ch);
STRS(i, ch)
if(ch[i] == '(') a++;
else{
a--;
if(a < b) b = a;
}
REP(i, -b) putchar('(');
printf(ch);
REP(i, a - b) putchar(')');
putchar('\n');
}
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