def dummy_return_in_loop_body(loop_body):
    """adds dummy return to last block of parfor loop body for CFG computation
    """
    # max is last block since we add it manually for prange
    last_label = max(loop_body.keys())
    scope = loop_body[last_label].scope
    const = ir.Var(scope, mk_unique_var("$const"), ir.Loc("parfors_dummy", -1))
    loop_body[last_label].body.append(
        ir.Return(const, ir.Loc("parfors_dummy", -1)))
    yield
    # remove dummy return
    loop_body[last_label].body.pop()
adds dummy return to last block of parfor loop body for CFG computation
    
numba/parfors/parfor.py