[llvm] [LangRef] inline asm: the instructions are treated opaquely (PR #157080)

[Ralf Jung via llvm-commits]

RalfJung wrote:

Yes I think allowing the compiler to *heuristically* analyze the asm string, e.g. for the purpose of scheduling decisions, is fine in principle. It's a bit unclear whether this even needs to be mentioned since it doesn't actually affect the semantics of the program.

It could still be undesirable if the scheduler decision turns out to be really bad once the code changes to something else. But that's more of a case-by-case thing than something that needs to go into the LangRef. @nikic @efriedma-quic what do you think?

Paging @Amanieu to ensure this is fine from a Rust perspective.

https://github.com/llvm/llvm-project/pull/157080