https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111137
Bug ID: 111137
Summary: Wrong code at -O2/3 since r12-1000-g6924b5e6bd3
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
CC: rguenth at gcc dot gnu.org
Target Milestone: ---
gcc at -O2/3 produces the wrong code.
Bisected to r12-1000-g6924b5e6bd3
Compiler explorer: https://godbolt.org/z/9fo5dxxhf
$ cat a.c
int printf(const char *, ...);
char a;
int b[3][8];
int c, e = 1, f, g;
short d;
int main() {
for (; e >= 0; e--) {
d = 1;
for (; d >= 0; d--) {
c = 0;
for (; c <= 1; c++) {
b[0][d * 2 + c + 1] = 0;
g = a <= '7';
b[g - 1 + d][c] ^= 1;
}
}
}
printf("%d\n", b[0][1]);
}
$
$ gcc -O0 a.c && ./a.out
1
$ gcc -O2 a.c && ./a.out
0
$
