rb_prev
rb_node = rb_prev(&node->rb);
iter = rb_prev(iter);
iter = rb_prev(iter);
iter = rb_prev(iter);
node = rb_prev(¬ifier->itree.rb);
node = rb_prev(&range->itree.rb);
node = rb_prev(&va->rb.node);
return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
return rb_hole_addr_to_node(rb_prev(&node->rb_hole_addr));