def split_o_flags_args(args):
    """
    Splits any /O args and returns them. Does not take care of flags overriding
    previous ones. Skips non-O flag arguments.

    ['/Ox', '/Ob1'] returns ['/Ox', '/Ob1']
    ['/Oxj', '/MP'] returns ['/Ox', '/Oj']
    """
    o_flags = []
    for arg in args:
        if not arg.startswith('/O'):
            continue
        flags = list(arg[2:])
        # Assume that this one can't be clumped with the others since it takes
        # an argument itself
        if 'b' in flags:
            o_flags.append(arg)
        else:
            o_flags += ['/O' + f for f in flags]
    return o_flags