Showcases some interesting and non-obvious optimizations that compilers can make on and around atomics. In particular, I liked this example: the following code
int x = 0;
std::atomic<int> y;
int dso() {
x = 0;
int z = y.load(std::memory_order_seq_cst);
y.store(0, std::memory_order_seq_cst);
x = 1;
return z;