/*
     * Find the first node up the search stack that does not move.
     *
     * The depth of the current item must be at least this level, since we
     * see it in that many levels of the stack.
     *
     * !!! Watch these loops carefully: they all rely on the value of i,
     * and the exit conditions to end up with the right values are
     * non-trivial.
     */
    ins = NULL; /* -Wconditional-uninitialized */
    for (i = 0; i < WT_SKIP_MAXDEPTH - 1; i++)
        if ((ins = PREV_INS(cbt, i + 1)) != current)
            break;

    /*
     * Find a starting point for the new search. That is either at the non-moving node if we found a
     * valid node, or the beginning of the next list down that is not the current node.
     *
     * Since it is the beginning of a list, and we know the current node is has a skip depth at
     * least this high, any node we find must sort before the current node.
     */
    if (ins == NULL || ins == current)
        for (; i >= 0; i--) {
            cbt->ins_stack[i] = NULL;
            cbt->next_stack[i] = NULL;
            ins = cbt->ins_head->head[i];
            if (ins != NULL && ins != current)
                break;
        }

       else { /* Drop down a level */
            cbt->ins_stack[i] = &ins->next[i];
            cbt->next_stack[i] = ins->next[i];
            --i;
        }