[llvm] [LangRef] Specify icmp on pointers to only compare address (PR #163936)

[Alexander Richardson via llvm-commits]

https://github.com/arichardson approved this pull request.

The wording looks good to me and matches my understanding of the discussion result. 

How to represent a full comparison including external state in IR can be decided later. 

https://github.com/llvm/llvm-project/pull/163936