https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111445
Bug ID: 111445
Summary: Wrong code at -Os on x86_64-linux-gnu since
r12-1077-g57bf3751511
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
CC: aldyh at redhat dot com
Target Milestone: ---
gcc at -Os produced the wrong code
Bisected to r12-1077-g57bf3751511
Compiler explorer: https://godbolt.org/z/1Ej5jxYPa
$ cat a.c
int printf(const char *, ...);
short a, b;
unsigned char c = 255;
int main() {
int d;
unsigned char e;
d = 0;
for (; a >= 0; a--) {
int *f = &d;
*f = c;
}
e = 0;
for (; (unsigned char)(d - 255) + e <= 1; e++)
printf("%d\n", b);
}
$
$ gcc -O0 a.c && ./a.out
0
0
$ gcc -Os a.c && ./a.out
$
