Your focus on hardware misses the big picture. Atomic operations also restrict what the compiler can reorder. Just because the simplest translation to assembly

Your focus on hardware misses the big picture. Atomic operations also restrict what the compiler can reorder. Just because the simplest translation to assembly yields a data dependency on ARM et al doesn't mean the compiler is obligated to honor that. The focus on standards is precisely because that's the only contract the compiler gives you. If you write code expecting to also get your target architecture's guarantees for free, you're writing software that is at best only incidentally correct until the next compiler update. I look around this thread and I don't see a group of people trolling you - I genuinely think you're missing the point.