--- old/test/hotspot/jtreg/compiler/c2/aarch64/TestVolatiles.java	2020-04-04 02:23:18.239335480 +0200
+++ new/test/hotspot/jtreg/compiler/c2/aarch64/TestVolatiles.java	2020-04-04 02:23:18.133336459 +0200
@@ -38,7 +38,8 @@
  * and <testtype> in {G1,
  *                    Serial,
  *                    Parallel,
- *                    Shenandoah}
+ *                    Shenandoah,
+ *                    ShenandoahIU}
  */
 
 
@@ -93,6 +94,13 @@
             procArgs[argcount - 3] = "-XX:+UnlockExperimentalVMOptions";
             procArgs[argcount - 2] = "-XX:+UseShenandoahGC";
             break;
+        case "ShenandoahIU":
+            argcount = 11;
+            procArgs = new String[argcount];
+            procArgs[argcount - 4] = "-XX:+UnlockExperimentalVMOptions";
+            procArgs[argcount - 3] = "-XX:+UseShenandoahGC";
+            procArgs[argcount - 2] = "-XX:ShenandoahGCMode=iu";
+            break;
         default:
             throw new RuntimeException("unexpected test type " + testType);
         }
@@ -323,6 +331,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                  // Shenandoah generates normal object graphs for
                  // volatile stores
                 matches = new String[] {
@@ -401,6 +410,7 @@
                 break;
 
             case "Shenandoah":
+            case "ShenandoahIU":
                  // Shenandoah generates normal object graphs for
                  // volatile stores
                 matches = new String[] {
@@ -490,6 +500,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 // For volatile CAS, Shenanodoah generates normal
                 // graphs with a shenandoah-specific cmpxchg
                 matches = new String[] {
@@ -567,6 +578,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 // For volatile CAS, Shenanodoah generates normal
                 // graphs with a shenandoah-specific cmpxchg
                 matches = new String[] {
@@ -672,6 +684,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 // For volatile CAS, Shenanodoah generates normal
                 // graphs with a shenandoah-specific cmpxchg
                 matches = new String[] {
@@ -749,6 +762,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 // For volatile CAS, Shenanodoah generates normal
                 // graphs with a shenandoah-specific cmpxchg
                 matches = new String[] {
@@ -834,6 +848,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 matches = new String[] {
                     "membar_release \\(elided\\)",
                     useCompressedOops ? "atomic_xchgw?_acq" : "atomic_xchg_acq",
@@ -909,6 +924,7 @@
                 };
                 break;
             case "Shenandoah":
+            case "ShenandoahIU":
                 matches = new String[] {
                     "membar_release",
                     "dmb ish",