What kind of cast are we talking about here? reinterpret_cast?

Likely we mean "apply floating-point promotions, floating-integral conversions, and floating-point conversions", but that should be spelled out somewhere, e.g. in the library definitions section.

Alternatively, just saying "converted" (with an optional cross-reference to [conv]) should be sufficient.

(Source: Dawn's list of issues discovered during review/integration of the math special functions.)