--- old/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-04-03 22:13:08.149239872 +0200
+++ new/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-04-03 22:13:08.039240603 +0200
@@ -46,6 +46,7 @@
 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
+#include "gc/shenandoah/shenandoahIUMode.hpp"
 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
@@ -397,6 +398,8 @@
   if (ShenandoahGCMode != NULL) {
     if (strcmp(ShenandoahGCMode, "normal") == 0) {
       _gc_mode = new ShenandoahNormalMode();
+    } else if (strcmp(ShenandoahGCMode, "iu") == 0) {
+      _gc_mode = new ShenandoahIUMode();
     } else if (strcmp(ShenandoahGCMode, "passive") == 0) {
       _gc_mode = new ShenandoahPassiveMode();
     } else {