diff --git a/include/llvm/Support/ThreadLocal.h b/include/llvm/Support/ThreadLocal.h
index 1a0a00fd515..2957034ec74 100644
--- a/include/llvm/Support/ThreadLocal.h
+++ b/include/llvm/Support/ThreadLocal.h
@@ -28,7 +28,12 @@ namespace llvm {
       ///
       /// This is embedded in the class and we avoid malloc'ing/free'ing it,
       /// to make this class more safe for use along with CrashRecoveryContext.
-      ThreadLocalDataTy data;
+      union {
+        char data[sizeof(ThreadLocalDataTy)];
+        struct {
+          ThreadLocalDataTy align_data;
+        };
+      };
     public:
       ThreadLocalImpl();
       virtual ~ThreadLocalImpl();
diff --git a/lib/Support/ThreadLocal.cpp b/lib/Support/ThreadLocal.cpp
index 1030a2b97db..17e0fe15b02 100644
--- a/lib/Support/ThreadLocal.cpp
+++ b/lib/Support/ThreadLocal.cpp
@@ -40,7 +40,7 @@ void ThreadLocalImpl::removeInstance() { data = 0; }
 namespace llvm {
 using namespace sys;
 
-ThreadLocalImpl::ThreadLocalImpl() : data(0) {
+ThreadLocalImpl::ThreadLocalImpl() : data() {
   typedef int SIZE_TOO_BIG[sizeof(pthread_key_t) <= sizeof(data) ? 1 : -1];
   pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
   int errorcode = pthread_key_create(key, NULL);
diff --git a/lib/Support/Windows/ThreadLocal.inc b/lib/Support/Windows/ThreadLocal.inc
index 99c6f4f63b3..057deb325d6 100644
--- a/lib/Support/Windows/ThreadLocal.inc
+++ b/lib/Support/Windows/ThreadLocal.inc
@@ -22,7 +22,7 @@
 namespace llvm {
 using namespace sys;
 
-ThreadLocalImpl::ThreadLocalImpl() : data(0) {
+ThreadLocalImpl::ThreadLocalImpl() : data() {
   typedef int SIZE_TOO_BIG[sizeof(DWORD) <= sizeof(data) ? 1 : -1];
   DWORD* tls = reinterpret_cast<DWORD*>(&data);
   *tls = TlsAlloc();