grt: check if congestion grid vectors are empty before shuffling them

Signed-off-by: Eder Monteiro <emrmonteiro@precisioninno.com>
The-OpenROAD-Project · Dec 30, 2024 · 7b7e7d3 · 7b7e7d3
1 parent a288d5b
commit 7b7e7d3
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/grt/src/fastroute/src/utility.cpp b/src/grt/src/fastroute/src/utility.cpp
@@ -2495,8 +2495,13 @@ void FastRouteCore::saveCongestion(const int iter)
     const int seed = 42;
     g.seed(seed);
 
-    utl::shuffle(congestionGridsV.begin(), congestionGridsV.end(), g);
-    utl::shuffle(congestionGridsH.begin(), congestionGridsH.end(), g);
+    if (!congestionGridsH.empty()) {
+      utl::shuffle(congestionGridsH.begin(), congestionGridsH.end(), g);
+    }
+
+    if (!congestionGridsV.empty()) {
+      utl::shuffle(congestionGridsV.begin(), congestionGridsV.end(), g);
+    }
   }
 
   const std::string marker_group_name = fmt::format(