It is quite hard to come with a reliable example, but (https://c.godbolt.org/z/56bfYszEb):
int* p = malloc(sizeof(int));
int v = *p;
if (!(v < 0 || v == 0 || v > 0)) {
exit(1);
}
This compiles into `exit(1)` in Clang under -O3.
How? That doesn’t seem like it should be possible. Why is that?