def constants(self):
        """
        A list of all of the constants that this expression ends up using.
        """
        constants = [ ]
        for k in self.__slots__:
            v = getattr(self, k)
            if isinstance(v, IRExpr):
                constants.extend(v.constants)
            elif isinstance(v, IRConst):
                constants.append(v)
        return constants
A list of all of the constants that this expression ends up using.