ARC stands for automatic reference counting, not atomic reference counting, so this criticism doesn't really apply. The LLVM docs say: > ARC makes no guarantee

ARC stands for automatic reference counting, not atomic reference counting, so this criticism doesn't really apply. The LLVM docs say: > ARC makes no guarantees in the presence of race conditions. So, it seems they agree with you, to the extent that they agree that full atomic reference counting would be a bad idea for performance optimisation, which is why they don't do it. https://clang.llvm.org/docs/AutomaticReferenceCounting.html https://clang.llvm.org/docs/AutomaticReferenceCounting.html