> IMHO, if both numbers are inside range 2^53...2^63, they should be compared
> using conversion to integers, despite of possible performance penalty.
Didn't Roberto say just that? Let me find it ...
| (In terms of implementation, it means that integer-float should be
| compared converting the float to an integer; if the conversion fails,
| the numbers cannot be equal.) That definition is simple, sounds
| sensible and easy to explain, and makes equality transitive.