https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123657
Bug ID: 123657
Summary: wrong code at -O3
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: jiangchangwu at smail dot nju.edu.cn
Target Milestone: ---
This program prints 0 at -O0/1/2/s and prints 2 at -O3:
int printf(const char *, ...);
int a;
int main() {
for (int b = 0; b < 21; b++) {
int c = b;
while (c)
a = c >>= 1;
}
printf("%d\n", a);
}
Compiler Explorer: https://godbolt.org/z/z7bMhE4Ge
