--- a/src/cpu/ppc/vm/ppc.ad	Tue Jun 21 10:13:54 2016 -0700
+++ b/src/cpu/ppc/vm/ppc.ad	Sat Jun 25 20:03:17 2016 +0100
@@ -5469,7 +5469,7 @@
 %}
 
 // Match loading integer and casting it to long.
-instruct loadI2L(iRegLdst dst, memory mem) %{
+instruct loadI2L(iRegLdst dst, memoryAlg4 mem) %{
   match(Set dst (ConvI2L (LoadI mem)));
   predicate(_kids[0]->_leaf->as_Load()->is_unordered());
   ins_cost(MEMORY_REF_COST);
@@ -5485,7 +5485,7 @@
 %}
 
 // Match loading integer and casting it to long - acquire.
-instruct loadI2L_ac(iRegLdst dst, memory mem) %{
+instruct loadI2L_ac(iRegLdst dst, memoryAlg4 mem) %{
   match(Set dst (ConvI2L (LoadI mem)));
   ins_cost(3*MEMORY_REF_COST);
 

--- a/src/share/vm/classfile/classLoaderData.cpp	Tue Jun 21 10:13:54 2016 -0700
+++ b/src/share/vm/classfile/classLoaderData.cpp	Sat Jun 25 20:03:17 2016 +0100
@@ -318,10 +318,6 @@
     }
     tty->print_cr("]");
   }
-
-  // In some rare cases items added to this list will not be freed elsewhere.
-  // To keep it simple, just free everything in it here.
-  free_deallocate_list();
 }
 
 oop ClassLoaderData::keep_alive_object() const {
@@ -817,6 +813,12 @@
     // called on all alive classes. See the comment in ClassLoaderDataGraph::clean_metaspaces.
     cld->free_deallocate_list();
   }
+
+  // In some rare cases items added to the unloading list will not be freed elsewhere.
+  // To keep it simple, walk the _unloading list also.
+  for (ClassLoaderData* cld = _unloading; cld != _saved_unloading; cld = cld->next()) {
+    cld->free_deallocate_list();
+  }
 }
 
 // CDS support

--- a/src/share/vm/classfile/classLoaderData.inline.hpp	Tue Jun 21 10:13:54 2016 -0700
+++ b/src/share/vm/classfile/classLoaderData.inline.hpp	Sat Jun 25 20:03:17 2016 +0100
@@ -40,7 +40,7 @@
 
 
 inline ClassLoaderData *ClassLoaderDataGraph::find_or_create(Handle loader, TRAPS) {
-  assert(loader() != NULL,"Must be a class loader");
+  guarantee(loader() != NULL && loader()->is_oop(), "Loader must be oop");
   // Gets the class loader data out of the java/lang/ClassLoader object, if non-null
   // it's already in the loader_data, so no need to add
   ClassLoaderData* loader_data= java_lang_ClassLoader::loader_data(loader());

--- a/src/share/vm/opto/stringopts.cpp	Tue Jun 21 10:13:54 2016 -0700
+++ b/src/share/vm/opto/stringopts.cpp	Sat Jun 25 20:03:17 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2016, 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
@@ -1640,6 +1640,17 @@
       kit.store_String_length(kit.control(), result, length);
     }
     kit.store_String_value(kit.control(), result, char_array);
+
+    // Do not let stores that initialize this object be reordered with
+    // a subsequent store that would make this object accessible by
+    // other threads.
+    // Record what AllocateNode this StoreStore protects so that
+    // escape analysis can go from the MemBarStoreStoreNode to the
+    // AllocateNode and eliminate the MemBarStoreStoreNode if possible
+    // based on the escape status of the AllocateNode.
+    AllocateNode* alloc = AllocateNode::Ideal_allocation(result, _gvn);
+    assert(alloc != NULL, "should be newly allocated");
+    kit.insert_mem_bar(Op_MemBarStoreStore, alloc->proj_out(AllocateNode::RawAddress));
   } else {
     result = C->top();
   }

--- a/test/compiler/native/TestDirtyInt.sh	Tue Jun 21 10:13:54 2016 -0700
+++ b/test/compiler/native/TestDirtyInt.sh	Sat Jun 25 20:03:17 2016 +0100
@@ -30,20 +30,19 @@
 ## @run shell/timeout=30 TestDirtyInt.sh
 ##
 
-if [ "${TESTSRC}" = "" ]
-then
-  TESTSRC=${PWD}
-  echo "TESTSRC not set.  Using "${TESTSRC}" as default"
+if [ -z "${TESTSRC}" ]; then
+    TESTSRC="${PWD}"
+    echo "TESTSRC not set.  Using "${TESTSRC}" as default"
 fi
 echo "TESTSRC=${TESTSRC}"
 ## Adding common setup Variables for running shell tests.
 . ${TESTSRC}/../../test_env.sh
 
 # set platform-dependent variables
-if [ $VM_OS == "linux" -a $VM_CPU == "sparcv9" ]; then
+if [ "$VM_OS" = "linux" -a "$VM_CPU" = "sparcv9" ]; then
     echo "Testing on linux-sparc"
     gcc_cmd=`which gcc`
-    if [ "x$gcc_cmd" == "x" ]; then
+    if [ -z "$gcc_cmd" ]; then
         echo "WARNING: gcc not found. Cannot execute test." 2>&1
         exit 0;
     fi
@@ -68,10 +67,9 @@
     -Djava.library.path=${TESTSRC}${FS} TestDirtyInt"
 
 echo "$cmd"
-eval $cmd 
+eval $cmd
 
-if [ $? = 0 ]
-then
+if [ $? = 0 ]; then
     echo "Test Passed"
     exit 0
 fi

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/compiler/stringopts/TestStringObjectInitialization.java	Sat Jun 25 20:03:17 2016 +0100
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2016, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+
+import java.util.Arrays;
+
+/*
+ * @test
+ * @bug 8159244
+ * @summary Verifies that no partially initialized String object escapes from
+ *          C2's String concat optimization in a highly concurrent setting.
+ *          This test triggers the bug in about 1 out of 10 runs.
+ * @compile -XDstringConcat=inline TestStringObjectInitialization.java
+ * @run main/othervm/timeout=300 -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops -XX:-CompactStrings
+ *                               -XX:-UseG1GC -XX:+UseParallelGC TestStringObjectInitialization
+ */
+public class TestStringObjectInitialization {
+
+    String myString;
+
+    public static void main(String[] args) throws Exception {
+        TestStringObjectInitialization t = new TestStringObjectInitialization();
+        // Create some threads that concurrently update 'myString'
+        for (int i = 0; i < 100; ++i) {
+            (new Thread(new Runner(t))).start();
+        }
+        Thread last = new Thread(new Runner(t));
+        last.start();
+        last.join();
+    }
+
+    private void add(String message) {
+        // String escapes to other threads here
+        myString += message;
+    }
+
+    public void run(String s, String[] sArray) {
+        // Trigger C2's string concatenation optimization
+        add(s + Arrays.toString(sArray) + " const ");
+    }
+}
+
+class Runner implements Runnable {
+    private TestStringObjectInitialization test;
+
+    public Runner(TestStringObjectInitialization t) {
+        test = t;
+    }
+
+    public void run(){
+        String[] array = {"a", "b", "c"};
+        for (int i = 0; i < 10000; ++i) {
+            test.run("a", array);
+        }
+    }
+}
+