Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18
diff --git a/unittests/Support/StringPool.cpp b/unittests/Support/StringPool.cpp
new file mode 100644
index 0000000..7b7805f
--- /dev/null
+++ b/unittests/Support/StringPool.cpp
@@ -0,0 +1,31 @@
+//===- llvm/unittest/Support/ThreadLocalTest.cpp - Therad Local tests   ---===//
+//
+//		       The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/StringPool.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(PooledStringPtrTest, OperatorEquals) {
+  StringPool pool;
+  const PooledStringPtr a = pool.intern("a");
+  const PooledStringPtr b = pool.intern("b");
+  EXPECT_FALSE(a == b);
+}
+
+TEST(PooledStringPtrTest, OperatorNotEquals) {
+  StringPool pool;
+  const PooledStringPtr a = pool.intern("a");
+  const PooledStringPtr b = pool.intern("b");
+  EXPECT_TRUE(a != b);
+}
+
+}