And for the half-initiated in IEEE 754, who think (like I used to) that all operations defined in the standard (including non-arithmetic ones) propagate NaNs, d

And for the half-initiated in IEEE 754, who think (like I used to) that all operations defined in the standard (including non-arithmetic ones) propagate NaNs, don't forget that pow is also defined (recommended, not obligatory), and that pow(NaN, 0) == 1, as well as pow(1, NaN) == 1, so there is a way to "lose" NaNs when using standard but non-arithmetic operations.