PR10140 - StringPool's PooledStringPtr has non-const operator== causing bad OR-result.

Mark conversion operator explicit and const qualify comparison operators.

llvm-svn: 211244
diff --git a/llvm/unittests/Support/StringPool.cpp b/llvm/unittests/Support/StringPool.cpp
new file mode 100644
index 0000000..7b7805f
--- /dev/null
+++ b/llvm/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);
+}
+
+}