diff -r 5d4c3724e4c7 -r 03fbcd06b4c0 src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.amd64/src/org/graalvm/compiler/lir/amd64/AMD64StringUTF16CompressOp.java
--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.amd64/src/org/graalvm/compiler/lir/amd64/AMD64StringUTF16CompressOp.java	Thu Nov 14 11:16:14 2019 -0800
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.amd64/src/org/graalvm/compiler/lir/amd64/AMD64StringUTF16CompressOp.java	Thu Nov 14 12:21:00 2019 -0800
@@ -340,4 +340,8 @@
         masm.bind(labelDone);
     }
 
+    @Override
+    public boolean needsClearUpperVectorRegisters() {
+        return true;
+    }
 }