I recently ran down approximately the same rabbit hole when trying to figure out what to do about x86 treating addition and bitwise OR differently. There's https://llvm.org/docs/LangRef.html#id171, but it can't generally be synthesized in Rust. So I went on a short-lived quest:

- https://internals.rust-lang.org/t/expose-llvms-or-disjoint-i...

- https://github.com/rust-lang/libs-team/issues/373

- https://github.com/rust-lang/rust/pull/124601

Which ultimately culminated in an opinion that should sound familiar - https://github.com/rust-lang/rust/pull/124601#issuecomment-2....