src/share/vm/gc/shenandoah/shenandoahHeapRegion.cpp

@@ -289,11 +289,14 @@
   // Reset C-TAMS pointer to ensure size-based iteration, everything
   // in that regions is going to be new objects.
   _heap->set_complete_top_at_mark_start(bottom(), bottom());
   // We can only safely reset the C-TAMS pointer if the bitmap is clear for that region.
   assert(_heap->is_complete_bitmap_clear_range(bottom(), end()), "must be clear");
+
+  if (UseShenandoahMatrix) {
   _heap->connection_matrix()->clear_region(region_number());
+  }
 }
 
 HeapWord* ShenandoahHeapRegion::block_start_const(const void* p) const {
   assert(MemRegion(bottom(), end()).contains(p),
          "p ("PTR_FORMAT") not in space ["PTR_FORMAT", "PTR_FORMAT")",