Representing `<=>` in IR

[Mitch_Alsup]

@Mitch_Alsup

Don’t think it matters much: but both of these imbodiments prefer it written in the form::

      ( a < b ) | ( a > b )

Which does not work –so, any of the following can be used::

 (a < b) ? -1 : (a == b) ? 0 : 1;

 (a == b) ? 0 : (a < b) ? -1 : 1;

 (a < b) ? -1 : (a > b) ? 1 : 0;

 (a > b) ? 1 : (a < b) ? -1 : 0;