[extraduder_ire]

IIRC, any comparison using a nan must fail (return false) according to the IEEE spec.

[kopecs]

I think it is a bit more complex, since NaN is defined to be "unordered" with respect to all other values (including other NaNs), and so any relation for which unordered values result in true (e.g., compareQuietNotEqual) will return true. (See section 5.11)