https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111210
Bug ID: 111210
Summary: Wrong code at -Os on x86_64-linux-gnu since
r12-4849-gf19791565d7
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
Target Milestone: ---
gcc at -Os produces the wrong code.
Bisected to r12-4849-gf19791565d7
Compiler explorer: https://godbolt.org/z/fjcEvKdYT
$ cat a.c
int printf(const char *, ...);
int a;
int *b = &a;
int c(long *d) {
if (*d)
return *(int *)0;
return *(int *)(d + 1);
}
int main() {
long e[] = {0, 100};
int f = c(e);
*b = f;
printf("%d\n", a);
}
$
$ gcc -O3 a.c && ./a.out
100
$ gcc -Os a.c && ./a.out
0
$
