Check that the path from loc1 to loc2 is clear.
    We have to check that there is no side effect between the two location
    points. We also have to check that the variable `reg` is not redefined
    along one of the possible pathes from loc1 to loc2.

def clear_path(graph, reg, loc1, loc2):
    """
    Check that the path from loc1 to loc2 is clear.
    We have to check that there is no side effect between the two location
    points. We also have to check that the variable `reg` is not redefined
    along one of the possible pathes from loc1 to loc2.
    """
    logger.debug('clear_path: reg(%s), loc1(%s), loc2(%s)', reg, loc1, loc2)
    node1 = graph.get_node_from_loc(loc1)
    node2 = graph.get_node_from_loc(loc2)
    # If both instructions are in the same node, we only have to check that the
    # path is clear inside the node
    if node1 is node2:
        return clear_path_node(graph, reg, loc1 + 1, loc2)

    # If instructions are in different nodes, we also have to check the nodes
    # in the path between the two locations.
    if not clear_path_node(graph, reg, loc1 + 1, node1.ins_range[1]):
        return False
    path = build_path(graph, node1, node2)
    for node in path:
        locs = node.ins_range
        end_loc = loc2 if (locs[0] <= loc2 <= locs[1]) else locs[1]
        if not clear_path_node(graph, reg, locs[0], end_loc):
            return False
    return True