diff --git a/vpr/src/route/connection_router.cpp b/vpr/src/route/connection_router.cpp
index 57543ca4867..70ebfa0f357 100644
--- a/vpr/src/route/connection_router.cpp
+++ b/vpr/src/route/connection_router.cpp
@@ -6,22 +6,6 @@
 #include "bucket.h"
 #include "rr_graph_fwd.h"
 
-/**
- * @brief This function is relevant when the architecture is 3D. If inter-layer connections are only from OPINs (determine by is_inter_layer_opin_connection),
- * then nodes (other that OPINs) which are on the other layer than sink's layer, don't need to be pushed back to the heap.
- * @param rr_nodes
- * @param rr_graph
- * @param from_node
- * @param sink_node
- * @param is_inter_layer_opin_connection It is true if the architecture is 3D and inter-layer connections are only from OPINs.
- * @return
- */
-static bool has_path_to_sink(const t_rr_graph_view& rr_nodes,
-                             const RRGraphView* rr_graph,
-                             RRNodeId from_node,
-                             RRNodeId sink_node,
-                             bool is_inter_layer_opin_connection);
-
 static bool relevant_node_to_target(const RRGraphView* rr_graph,
                                     RRNodeId node_to_add,
                                     RRNodeId target_node);
@@ -852,9 +836,6 @@ void ConnectionRouter<Heap>::add_route_tree_to_heap(
     /* Pre-order depth-first traversal */
     // IPINs and SINKS are not re_expanded
     if (rt_node.re_expand) {
-        if (target_node.is_valid() && !has_path_to_sink(rr_nodes_, rr_graph_, RRNodeId(rt_node.inode), RRNodeId(target_node), only_opin_inter_layer)) {
-            return;
-        }
         add_route_tree_node_to_heap(rt_node,
                                     target_node,
                                     cost_params,
@@ -1020,9 +1001,6 @@ t_bb ConnectionRouter<Heap>::add_high_fanout_route_tree_to_heap(
                 if (!inside_bb(rr_node_to_add, net_bounding_box))
                     continue;
 
-                if (!has_path_to_sink(rr_nodes_, rr_graph_, RRNodeId(rt_node.inode), target_node, only_opin_inter_layer)) {
-                    continue;
-                }
                 // Put the node onto the heap
                 add_route_tree_node_to_heap(rt_node, target_node, cost_params, net_bounding_box);
 
@@ -1059,31 +1037,6 @@ t_bb ConnectionRouter<Heap>::add_high_fanout_route_tree_to_heap(
     }
 }
 
-static inline bool has_path_to_sink(const t_rr_graph_view& rr_nodes,
-                                    const RRGraphView* rr_graph,
-                                    RRNodeId from_node,
-                                    RRNodeId sink_node,
-                                    bool is_inter_layer_opin_connection) {
-    int sink_layer = rr_graph->node_layer(sink_node);
-
-    if (rr_graph->node_layer(from_node) == sink_layer || rr_graph->node_type(from_node) == SOURCE || !is_inter_layer_opin_connection) {
-        return true;
-    } else if (rr_graph->node_type(from_node) == CHANX || rr_graph->node_type(from_node) == CHANY || rr_graph->node_type(from_node) == IPIN) {
-        return false;
-    } else {
-        VTR_ASSERT(rr_graph->node_type(from_node) == OPIN && is_inter_layer_opin_connection);
-        auto edges = rr_nodes.edge_range(from_node);
-
-        for (RREdgeId from_edge : edges) {
-            RRNodeId to_node = rr_nodes.edge_sink_node(from_edge);
-            if (rr_graph->node_layer(to_node) == sink_layer) {
-                return true;
-            }
-        }
-        return false;
-    }
-}
-
 static inline bool relevant_node_to_target(const RRGraphView* rr_graph,
                                            RRNodeId node_to_add,
                                            RRNodeId target_node) {