From 4b54e6fad194431ada07e55d5ff6991a6b7d0cbc Mon Sep 17 00:00:00 2001
From: tangxifan <tangxifan@gmail.com>
Date: Thu, 15 Aug 2024 20:12:31 -0700
Subject: [PATCH] [core] fixed a corner case where spine usage should be
 updated after each switch point connection

---
 openfpga/src/annotation/route_clock_rr_graph.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/openfpga/src/annotation/route_clock_rr_graph.cpp b/openfpga/src/annotation/route_clock_rr_graph.cpp
index 59e438a02..79cad9ecb 100644
--- a/openfpga/src/annotation/route_clock_rr_graph.cpp
+++ b/openfpga/src/annotation/route_clock_rr_graph.cpp
@@ -411,6 +411,9 @@ static int rec_expand_and_route_clock_spine(
         return CMD_EXEC_FATAL_ERROR;
       }
     }
+    if (curr_stop_usage) {
+      curr_spine_usage = true;
+    }
     if (disable_unused_spines && !curr_stop_usage && !prev_stop_usage) {
       VTR_LOGV(verbose,
                "Disconnect backbone of spine '%s' at (x=%lu, y=%lu) as "