--- old/src/hotspot/share/gc/z/zStat.cpp	2019-11-21 11:54:15.756032261 +0100
+++ new/src/hotspot/share/gc/z/zStat.cpp	2019-11-21 11:54:15.496027863 +0100
@@ -424,9 +424,9 @@
   for (uint32_t i = 0; i < ncpus; i++) {
     ZStatSamplerData* const cpu_data = get_cpu_local<ZStatSamplerData>(i);
     if (cpu_data->_nsamples > 0) {
-      const uint64_t nsamples = Atomic::xchg((uint64_t)0, &cpu_data->_nsamples);
-      const uint64_t sum = Atomic::xchg((uint64_t)0, &cpu_data->_sum);
-      const uint64_t max = Atomic::xchg((uint64_t)0, &cpu_data->_max);
+      const uint64_t nsamples = Atomic::xchg(&cpu_data->_nsamples, (uint64_t)0);
+      const uint64_t sum = Atomic::xchg(&cpu_data->_sum, (uint64_t)0);
+      const uint64_t max = Atomic::xchg(&cpu_data->_max, (uint64_t)0);
       all._nsamples += nsamples;
       all._sum += sum;
       if (all._max < max) {
@@ -459,7 +459,7 @@
   const uint32_t ncpus = ZCPU::count();
   for (uint32_t i = 0; i < ncpus; i++) {
     ZStatCounterData* const cpu_data = get_cpu_local<ZStatCounterData>(i);
-    counter += Atomic::xchg((uint64_t)0, &cpu_data->_counter);
+    counter += Atomic::xchg(&cpu_data->_counter, (uint64_t)0);
   }
 
   ZStatSample(_sampler, counter);
@@ -481,7 +481,7 @@
   const uint32_t ncpus = ZCPU::count();
   for (uint32_t i = 0; i < ncpus; i++) {
     ZStatCounterData* const cpu_data = get_cpu_local<ZStatCounterData>(i);
-    all._counter += Atomic::xchg((uint64_t)0, &cpu_data->_counter);
+    all._counter += Atomic::xchg(&cpu_data->_counter, (uint64_t)0);
   }
 
   return all;