--- old/src/hotspot/share/gc/parallel/psYoungGen.cpp	2018-04-27 15:29:47.198202799 +0200
+++ new/src/hotspot/share/gc/parallel/psYoungGen.cpp	2018-04-27 15:29:46.954202807 +0200
@@ -730,6 +730,8 @@
   to_space()->object_iterate(blk);
 }
 
+#if INCLUDE_SERIALGC
+
 void PSYoungGen::precompact() {
   eden_mark_sweep()->precompact();
   from_mark_sweep()->precompact();
@@ -749,6 +751,8 @@
   to_mark_sweep()->compact(false);
 }
 
+#endif // INCLUDE_SERIALGC
+
 void PSYoungGen::print() const { print_on(tty); }
 void PSYoungGen::print_on(outputStream* st) const {
   st->print(" %-15s", "PSYoungGen");