--- old/src/cpu/aarch64/vm/shenandoahBarrierSetAssembler_aarch64.cpp	2019-10-28 20:26:19.092486462 +0100
+++ new/src/cpu/aarch64/vm/shenandoahBarrierSetAssembler_aarch64.cpp	2019-10-28 20:26:19.006486467 +0100
@@ -65,9 +65,14 @@
   if (borrow_reg) {
     // No free registers available. Make one useful.
     tmp = rscratch1;
+    if (tmp == dst) {
+      tmp = rscratch2;
+    }
     __ push(RegSet::of(tmp), sp);
   }
 
+  assert_different_registers(tmp, dst);
+
   Label done;
   __ ldr(tmp, Address(dst, oopDesc::mark_offset_in_bytes()));
   __ eon(tmp, tmp, zr);