diff -r e92153ed8bdc -r 29b0d0b61615 src/hotspot/share/gc/z/zRelocationSet.inline.hpp
--- a/src/hotspot/share/gc/z/zRelocationSet.inline.hpp	Mon Nov 25 12:30:24 2019 +0100
+++ b/src/hotspot/share/gc/z/zRelocationSet.inline.hpp	Mon Nov 25 12:31:39 2019 +0100
@@ -38,7 +38,7 @@
 
   if (parallel) {
     if (_next < nforwardings) {
-      const size_t next = Atomic::add(1u, &_next) - 1u;
+      const size_t next = Atomic::add(&_next, 1u) - 1u;
       if (next < nforwardings) {
         *forwarding = _relocation_set->_forwardings[next];
         return true;