--- a/hotspot/src/share/vm/c1/c1_GraphBuilder.cpp	Fri Nov 06 10:06:51 2015 -1000
+++ b/hotspot/src/share/vm/c1/c1_GraphBuilder.cpp	Wed Oct 21 10:37:50 2015 +0200
@@ -1438,7 +1438,9 @@
 
   bool need_mem_bar = false;
   if (method()->name() == ciSymbol::object_initializer_name() &&
-      (scope()->wrote_final() || (AlwaysSafeConstructors && scope()->wrote_fields()))) {
+      (scope()->wrote_final() || (AlwaysSafeConstructors && scope()->wrote_fields())
+                              || (support_IRIW_for_not_multiple_copy_atomic_cpu && scope()->wrote_volatile())
+     )){
     need_mem_bar = true;
   }
 
@@ -1554,6 +1556,9 @@
 
   if (code == Bytecodes::_putfield) {
     scope()->set_wrote_fields();
+    if (field->is_volatile()) {
+      scope()->set_wrote_volatile();
+    }
   }
 
   const int offset = !needs_patching ? field->offset() : -1;

--- a/hotspot/src/share/vm/c1/c1_IR.cpp	Fri Nov 06 10:06:51 2015 -1000
+++ b/hotspot/src/share/vm/c1/c1_IR.cpp	Wed Oct 21 10:37:50 2015 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -143,6 +143,7 @@
   _monitor_pairing_ok = method->has_balanced_monitors();
   _wrote_final        = false;
   _wrote_fields       = false;
+  _wrote_volatile     = false;
   _start              = NULL;
 
   if (osr_bci == -1) {

--- a/hotspot/src/share/vm/c1/c1_IR.hpp	Fri Nov 06 10:06:51 2015 -1000
+++ b/hotspot/src/share/vm/c1/c1_IR.hpp	Wed Oct 21 10:37:50 2015 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -151,6 +151,7 @@
   bool          _monitor_pairing_ok;             // the monitor pairing info
   bool          _wrote_final;                    // has written final field
   bool          _wrote_fields;                   // has written fields
+  bool          _wrote_volatile;                 // has written volatile field
   BlockBegin*   _start;                          // the start block, successsors are method entries
 
   BitMap        _requires_phi_function;          // bit is set if phi functions at loop headers are necessary for a local variable
@@ -187,7 +188,8 @@
   bool          wrote_final    () const          { return _wrote_final; }
   void          set_wrote_fields()               { _wrote_fields = true; }
   bool          wrote_fields    () const         { return _wrote_fields; }
-
+  void          set_wrote_volatile()             { _wrote_volatile = true; }
+  bool          wrote_volatile    () const       { return _wrote_volatile; }
 };
 
 

--- a/hotspot/src/share/vm/c1/c1_LIRGenerator.cpp	Fri Nov 06 10:06:51 2015 -1000
+++ b/hotspot/src/share/vm/c1/c1_LIRGenerator.cpp	Wed Oct 21 10:37:50 2015 +0200
@@ -1761,7 +1761,7 @@
     post_barrier(object.result(), value.result());
   }
 
-  if (is_volatile && os::is_MP()) {
+  if (!support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile && os::is_MP()) {
     __ membar();
   }
 }
@@ -1822,6 +1822,10 @@
     address = generate_address(object.result(), x->offset(), field_type);
   }
 
+  if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile && os::is_MP()) {
+    __ membar();
+  }
+
   bool needs_atomic_access = is_volatile || AlwaysAtomicAccesses;
   if (needs_atomic_access && !needs_patching) {
     volatile_field_load(address, reg, info);
@@ -2238,6 +2242,10 @@
 
   LIR_Opr value = rlock_result(x, x->basic_type());
 
+  if (support_IRIW_for_not_multiple_copy_atomic_cpu && x->is_volatile() && os::is_MP()) {
+    __ membar();
+  }
+
   get_Object_unsafe(value, src.result(), off.result(), type, x->is_volatile());
 
 #if INCLUDE_ALL_GCS
@@ -2395,7 +2403,7 @@
 
   if (x->is_volatile() && os::is_MP()) __ membar_release();
   put_Object_unsafe(src.result(), off.result(), data.result(), type, x->is_volatile());
-  if (x->is_volatile() && os::is_MP()) __ membar();
+  if (!support_IRIW_for_not_multiple_copy_atomic_cpu && x->is_volatile() && os::is_MP()) __ membar();
 }