With both flags atomic and ALL operations using memory_order_relaxed (initial values 0), is the outcome r1 == 0 && r2 == 0 possible?
// x, y atomic<int> = 0
// T1: x.store(1, relaxed); r1 = y.load(relaxed);
// T2: y.store(1, relaxed); r2 = x.load(relaxed);