[llvm] LangRef: Clarify llvm.minnum and llvm.maxnum about sNaN (PR #112852)

[Joshua Cranmer via llvm-commits]

https://github.com/jcranmer-intel commented:

I'm not convinced this change is a good idea, as opposed to fixing the backends that implement it differently. LLVM has a general principle that sNaNs are treated more or less equivalent to qNaN, and this is the main case where sNaN inputs do very different things from qNaN inputs. The original text is pretty explicit that targets are supposed to use `llvm.canonicalize` to handle sNaN quieting if they're mapping to hardware that does distinguish between sNaN/qNaN, and I don't see any justification in this PR yet for why doing that is problematic.

https://github.com/llvm/llvm-project/pull/112852