https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117424
Bug ID: 117424
Summary: Miscompile with different optimization flags
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: yunboni at smail dot nju.edu.cn
Target Milestone: ---
When I compiled this case by -O3, it terminated with signal: SIGSEGV. When
compiled with -O0/O1/O2, its output is 0:
```c
int printf(const char *, ...);
int a;
unsigned char c;
int e(int f) {
int d = f * 10;
return d;
}
int g(int f, int *l) {
int h = 0;
for (int j = 0; j < 10; j++)
for (int k = 0; k < f; k++)
if (l[k])
h++;
return h;
}
int m(int f) {
int b = 0, n = g(f, &b);
return n;
}
int main() {
int i = 0;
for (; e(c + 77) + c - 836 + i < 2; i++)
for (; m(c - 5);)
;
printf("%d\n", a);
}
```
The version of gcc is 12.1. Details can be found here:
https://godbolt.org/z/1Kd4s4K7x.
I've checked the code with -Wall and -Wextra, no warning has appeared.
