https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108360
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Seems it happens even with
short b;
static short c;
unsigned char e;
char f;
void foo();
short(a)(short h, short i) { return h + i; }
static short(d)(short h, int i) { return (h >= 32 || h > (7 >> i)) ? h : h <<
i; }
unsigned g(short h, short i) { return h + i; }
int main() {
short j, k = -1;
c = a(0 >= b, k);
f = c <= 0xD315BEF1;
e = f << 4;
j = d(e, 5);
if (3 >= g(j == b, k))
foo();
b = 32;
}
where we can't assume anything about b's value initially.
Still in GCC 12 we decide to thread jump it based on whether e (h in inlined d)
is 0 or non-0 - h >= 32 is based on ranges clearly always false and as e has
[0, 16] range, h > 0 and h != 0 are the same thing, if h != 0, then d returns
h, otherwise h << 5. Later on we correctly figure out that if h == 0, then h
<< 5 is 0. But what I really don't understand how threadfull1 in that case
decided that foo will not be called.
