[llvm] SelectionDAG/expandFMINIMUMNUM_FMAXIMUMNUM: FCANONICALIZE is needed only for sNaN (PR #108180)

[YunQiang Su via llvm-commits]

wzssyqa wrote:

I guess t hat I am confused by `nofpclass` in https://llvm.org/docs/LangRef.html#id1932.
Can it used to mark an argument that it will never be a type?

I have a try, while it won't as `DAG.isKnownNeverNaN` won't return true in this case.
Maybe I misunderstand its meaning.

https://github.com/llvm/llvm-project/pull/108180