def supported_ufunc_loop(ufunc, loop):
    """Return whether the *loop* for the *ufunc* is supported -in nopython-.

    *loop* should be a UFuncLoopSpec instance, and *ufunc* a numpy ufunc.

    For ufuncs implemented using the ufunc_db, it is supported if the ufunc_db
    contains a lowering definition for 'loop' in the 'ufunc' entry.

    For other ufuncs, it is type based. The loop will be considered valid if it
    only contains the following letter types: '?bBhHiIlLqQfd'. Note this is
    legacy and when implementing new ufuncs the ufunc_db should be preferred,
    as it allows for a more fine-grained incremental support.
    """
    # NOTE: Assuming ufunc for the CPUContext
    from numba.np import ufunc_db
    loop_sig = loop.ufunc_sig
    try:
        # check if the loop has a codegen description in the
        # ufunc_db. If so, we can proceed.

        # note that as of now not all ufuncs have an entry in the
        # ufunc_db
        supported_loop = loop_sig in ufunc_db.get_ufunc_info(ufunc)
    except KeyError:
        # for ufuncs not in ufunc_db, base the decision of whether the
        # loop is supported on its types
        loop_types = [x.char for x in loop.numpy_inputs + loop.numpy_outputs]
        supported_types = '?bBhHiIlLqQfd'
        # check if all the types involved in the ufunc loop are
        # supported in this mode
        supported_loop = all(t in supported_types for t in loop_types)

    return supported_loop
Return whether the *loop* for the *ufunc* is supported -in nopython-.

    *loop* should be a UFuncLoopSpec instance, and *ufunc* a numpy ufunc.

    For ufuncs implemented using the ufunc_db, it is supported if the ufunc_db
    contains a lowering definition for 'loop' in the 'ufunc' entry.

    For other ufuncs, it is type based. The loop will be considered valid if it
    only contains the following letter types: '?bBhHiIlLqQfd'. Note this is
    legacy and when implementing new ufuncs the ufunc_db should be preferred,
    as it allows for a more fine-grained incremental support.
    
numba/np/numpy_support.py