https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111422
Bug ID: 111422
Summary: Wrong code at -O3 on x86_64-linux-gnu
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
Target Milestone: ---
gcc at -O3 produced the wrong code.
Compiler explorer: https://godbolt.org/z/3b4v478TG
$ cat a.c
int printf(const char *, ...);
int a, b;
int *c = &b;
unsigned d;
char e;
int f=1;
int i(int k, char *l) {
if (k < 6)
return a;
l[0] = l[1] = l[k - 1] = 8;
return 0;
}
int m(int k) {
char g[11];
int h = i(k, g);
return h;
}
int main() {
for (; b < 8; b = b + 1)
;
int j;
int *n[8];
j = 0;
for (;18446744073709551608U + m(*c) + *c + j < 2; j++){
n[j] = &f;
}
for (; e <= 4; e++)
d = *n[0] == f;
printf("%d\n", d);
}
$
$ gcc -O0 a.c && ./a.out
1
$ gcc -O3 a.c && ./a.out
Segmentation fault
$ gcc -O3 -fwrapv a.c && ./a.out
Segmentation fault
$ gcc -fsanitize=address,undefined a.c && ./a.out
1
$
