--- a/src/hotspot/share/gc/g1/heapRegion.cpp	Fri Dec 07 13:15:35 2018 +0100
+++ b/src/hotspot/share/gc/g1/heapRegion.cpp	Fri Dec 07 13:54:45 2018 +0100
@@ -26,6 +26,7 @@
 #include "code/nmethod.hpp"
 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
 #include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectionSet.hpp"
 #include "gc/g1/g1HeapRegionTraceType.hpp"
 #include "gc/g1/g1OopClosures.inline.hpp"
 #include "gc/g1/heapRegion.inline.hpp"
@@ -240,7 +241,8 @@
     _containing_set(NULL),
 #endif
     _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
-    _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
+    _index_in_opt_cset(G1OptionalCSet::InvalidCSetIndex), _young_index_in_cset(-1),
+    _surv_rate_group(NULL), _age_index(-1),
     _prev_top_at_mark_start(NULL), _next_top_at_mark_start(NULL),
     _recorded_rs_length(0), _predicted_elapsed_time_ms(0)
 {