I'm sorry, this is perhaps not the correct component but my knowledge of gcc internals does not allow me to do more than guess.

For all version of gcc I've tried, the following code:

struct point {
    int x, y;
};

bool f(point a, point b) {
    return a.x == b.x && a.y == b.y;
}

bool f(unsigned long long a, unsigned long long b) {
    return a == b;
}

is compiled to

f(point, point):
        xor     eax, eax
        cmp     edi, esi
        je      .L5
        ret
.L5:
        sar     rdi, 32
        sar     rsi, 32
        cmp     edi, esi
        sete    al
        ret
f(unsigned long long, unsigned long long):
        cmp     rdi, rsi
        sete    al
        ret

I'd expect f(point, point) to have the same assembly as f(unsigned long long, unsigned long long).

Yours,

-- Jean-Marc Bourguet