# HG changeset patch
# Parent  a137bdf9f50c802cb32ba55ed7c5326a685236b6

diff -r a137bdf9f50c -r d62b0355010d src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
--- a/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp	Mon Sep 30 22:39:11 2019 +0200
+++ b/src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp	Fri Oct 04 09:42:56 2019 +0200
@@ -619,21 +619,26 @@
   // with to-space ptr store. We still have to do the retry, because the GC might
   // have updated the reference for us.
 
+  if (os::is_MP()) __ lock();
+#ifdef _LP64
+  if (UseCompressedOops) {
+    __ cmpxchgl(newval, addr);
+  } else
+#endif
+  {
+    __ cmpxchgptr(newval, addr);
+  }
+
+  __ jcc(Assembler::equal, L_success);
+
 #ifdef _LP64
   if (UseCompressedOops) {
     __ encode_heap_oop(tmp2); // previously decoded at step 2.
   }
 #endif
 
-  if (os::is_MP()) __ lock();
-#ifdef _LP64
-  if (UseCompressedOops) {
-    __ cmpxchgl(tmp2, addr);
-  } else
-#endif
-  {
-    __ cmpxchgptr(tmp2, addr);
-  }
+  __ cmpptr(oldval, tmp2);
+  __ jccb(Assembler::notEqual, L_failure);
 
   // Step 4. Try to CAS again.
   //
@@ -642,15 +647,6 @@
   // from-space ptr into memory anymore. Make sure oldval is restored, after being
   // garbled during retries.
   //
-#ifdef _LP64
-  if (UseCompressedOops) {
-    __ movl(oldval, tmp2);
-  } else
-#endif
-  {
-    __ movptr(oldval, tmp2);
-  }
-
   if (os::is_MP()) __ lock();
 #ifdef _LP64
   if (UseCompressedOops) {