diff --git a/common/place/placer_heap.cc b/common/place/placer_heap.cc
index 2ed2cdeb..96f94266 100644
--- a/common/place/placer_heap.cc
+++ b/common/place/placer_heap.cc
@@ -859,7 +859,7 @@ class HeAPPlacer
         for (auto cell : place_cells) {
             chain_size[cell->name] = 1;
             if (cell->cluster != ClusterId()) {
-                const auto base = cell_locs[cell->name];
+                const auto base = cell_locs[ctx->getClusterRootCell(cell->cluster)->name];
                 for (auto child : cluster2cells.at(cell->cluster)) {
                     if (child != cell)
                         chain_size[cell->name]++;