With -O option, uint division is performed as int division.

    int main() {
        uint f(uint n) { return n % 10; }

        printf("%u\n", uint.max);
        printf("%u\n", f(uint.max));
        printf("%d\n", uint.max);
        printf("%d\n", f(uint.max));

        return 0;
    }

Without -O:
    4294967295
    5
    -1
    5

With -O:
    4294967295
    4294967295
    -1
    -1

If the division is performed directly (i.e. uint.max % 10),
it works both with and without -O option.
This is a bug of inline expansion, isn't it?