[llvm] [RFC][LangRef] Specify that the accessed bytes of concurrent atomics must be either disjoint or the same (PR #204329)

[Fabian Ritter via llvm-commits]

ritter-x2a wrote:

### Merge activity

* **Jul 21, 7:16 AM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.com/github/pr/llvm/llvm-project/204329).


https://github.com/llvm/llvm-project/pull/204329