[libcxx-commits] [PATCH] D72240: Implement C++20 std::atomic_ref and test

[Olivier Giroux via Phabricator via libcxx-commits]

__simt__ added a comment.

That's a creative use of __cxx_atomic_impl that I hadn't foreseen. Seems to work. Ok.

It would be good if we could de-duplicate code here, because we're on a trajectory of having 4+ versions of every function that differ only on the type they take. Sounds like a perfect opportunity to sprinkle some enable_if here with a helper trait to determine if the thing is a __cxx_atomic_impl, volatile __cxx_atomic_impl, __cxx_atomic_impl of reference, or volatile __cxx_atomic_impl of reference.

As for the freestanding mode (or to be more accurate, the builtin-only mode) the only option you have for atomic_ref is to static_assert that it is always lock-free. There is presently 1 platform that builds with this mode (CUDA 10.2+) and this is what we planned to do anyway.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D72240/new/

https://reviews.llvm.org/D72240