Add a new API count_rr_switches() to RRGraphBuilder

vpr/src/device/rr_graph_builder.h

@@ -108,6 +108,15 @@ class RRGraphBuilder {
         node_storage_.add_node_side(id, new_side);
     }
 
+    /** @brief Counts the number of rr switches needed based on fan in to support mux
+     * size dependent switch delays. */
+    inline size_t count_rr_switches(
+        size_t num_arch_switches,
+        t_arch_switch_inf* arch_switch_inf,
+        t_arch_switch_fanin& arch_switch_fanins) {
+        return node_storage_.count_rr_switches(num_arch_switches, arch_switch_inf, arch_switch_fanins);
+    }
+
     /* -- Internal data storage -- */
   private:
     /* TODO: When the refactoring effort finishes, 

vpr/src/route/rr_graph.cpp

@@ -819,7 +819,7 @@ static void alloc_rr_switch_inf(t_arch_switch_fanin& arch_switch_fanins) {
     auto& device_ctx = g_vpr_ctx.mutable_device();
 
     /* allocate space for the rr_switch_inf array */
-    size_t num_rr_switches = device_ctx.rr_nodes.count_rr_switches(
+    size_t num_rr_switches = device_ctx.rr_graph_builder.count_rr_switches(
         device_ctx.num_arch_switches,
         device_ctx.arch_switch_inf,
         arch_switch_fanins);