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

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

Please add some mention of the interaction with FP arithmetic. (In particular, that arithmetic on an sNaN doesn't consistently produce a qNaN, so arithmetic feeding into a minnum/maxnum can produce inconsistent results.)

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