elif isinstance(op, ast.Lt):
        pred = 'ult'
      elif isinstance(op, ast.LtE):
        pred = 'ule'
      elif isinstance(op, ast.Gt):
        pred = 'ugt'
      elif isinstance(op, ast.GtE):
        pred = 'uge'
      elif isinstance(op, ast.NotEq):
        pred = 'ne'
      else:
        raise NotImplementedError('Compare operator not recognized')

      ret = self._ssa_name(pred)