diff --git a/include/swift/Basic/ThreadSafeRefCounted.h b/include/swift/Basic/ThreadSafeRefCounted.h
index b8aa30ddaa343..7c3516b3eee65 100644
--- a/include/swift/Basic/ThreadSafeRefCounted.h
+++ b/include/swift/Basic/ThreadSafeRefCounted.h
@@ -15,37 +15,10 @@
 
 #include <atomic>
 #include <cassert>
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
 
 namespace swift {
 
-/// A thread-safe version of \c llvm::RefCountedBase.
-///
-/// A generic base class for objects that wish to have their lifetimes managed
-/// using reference counts. Classes subclass \c ThreadSafeRefCountedBase to
-/// obtain such functionality, and are typically handled with
-/// \c IntrusiveRefCntPtr "smart pointers" which automatically handle the
-/// management of reference counts.
-/// FIXME: This should eventually move to llvm.
-template <class Derived>
-class ThreadSafeRefCountedBase {
-  mutable std::atomic<unsigned> ref_cnt;
-
-protected:
-  ThreadSafeRefCountedBase() : ref_cnt(0) {}
-
-public:
-  void Retain() const {
-    ref_cnt.fetch_add(1, std::memory_order_acq_rel);
-  }
-
-  void Release() const {
-    int refCount =
-        static_cast<int>(ref_cnt.fetch_sub(1, std::memory_order_acq_rel));
-    assert(refCount >= 0 && "Reference count was already zero.");
-    if (refCount == 0) delete static_cast<const Derived*>(this);
-  }
-};
-
 /// A class that has the same function as \c ThreadSafeRefCountedBase, but with
 /// a virtual destructor.
 ///
@@ -62,12 +35,11 @@ class ThreadSafeRefCountedBaseVPTR {
 
 public:
   void Retain() const {
-    ref_cnt.fetch_add(1, std::memory_order_acq_rel);
+    ref_cnt += 1;
   }
 
   void Release() const {
-    int refCount =
-        static_cast<int>(ref_cnt.fetch_sub(1, std::memory_order_acq_rel));
+    int refCount = static_cast<int>(--ref_cnt);
     assert(refCount >= 0 && "Reference count was already zero.");
     if (refCount == 0) delete this;
   }
diff --git a/include/swift/IDE/CodeCompletionCache.h b/include/swift/IDE/CodeCompletionCache.h
index 14e0b7c79fc61..e13e31b85b6e7 100644
--- a/include/swift/IDE/CodeCompletionCache.h
+++ b/include/swift/IDE/CodeCompletionCache.h
@@ -49,7 +49,7 @@ class CodeCompletionCache {
     }
   };
 
-  struct Value : public ThreadSafeRefCountedBase<Value> {
+  struct Value : public llvm::ThreadSafeRefCountedBase<Value> {
     llvm::sys::TimeValue ModuleModificationTime;
     CodeCompletionResultSink Sink;
   };
diff --git a/tools/SourceKit/include/SourceKit/Core/LLVM.h b/tools/SourceKit/include/SourceKit/Core/LLVM.h
index 449b72c740e96..f54234db21a75 100644
--- a/tools/SourceKit/include/SourceKit/Core/LLVM.h
+++ b/tools/SourceKit/include/SourceKit/Core/LLVM.h
@@ -43,6 +43,7 @@ namespace llvm {
   // Reference counting.
   template <typename T> class IntrusiveRefCntPtr;
   template <typename T> struct IntrusiveRefCntPtrInfo;
+  template <class Derived> class ThreadSafeRefCountedBase;
 
   class raw_ostream;
   // TODO: DenseMap, ...
@@ -69,7 +70,6 @@ namespace llvm {
 }
 
 namespace swift {
-  template <class Derived> class ThreadSafeRefCountedBase;
   class ThreadSafeRefCountedBaseVPTR;
 }
 
@@ -95,7 +95,7 @@ namespace SourceKit {
   // Reference counting.
   using llvm::IntrusiveRefCntPtr;
   using llvm::IntrusiveRefCntPtrInfo;
-  using swift::ThreadSafeRefCountedBase;
+  using llvm::ThreadSafeRefCountedBase;
   using swift::ThreadSafeRefCountedBaseVPTR;
   template <typename T> class ThreadSafeRefCntPtr;
 
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftInterfaceGenContext.h b/tools/SourceKit/lib/SwiftLang/SwiftInterfaceGenContext.h
index bfbd7e8a7d635..f3cbedbff8f4f 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftInterfaceGenContext.h
+++ b/tools/SourceKit/lib/SwiftLang/SwiftInterfaceGenContext.h
@@ -31,7 +31,7 @@ namespace SourceKit {
   typedef IntrusiveRefCntPtr<ASTUnit> ASTUnitRef;
 
 class SwiftInterfaceGenContext :
-  public swift::ThreadSafeRefCountedBase<SwiftInterfaceGenContext> {
+  public llvm::ThreadSafeRefCountedBase<SwiftInterfaceGenContext> {
 public:
   static SwiftInterfaceGenContextRef create(StringRef DocumentName,
                                             bool IsModule,
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftInvocation.h b/tools/SourceKit/lib/SwiftLang/SwiftInvocation.h
index 6413acb2ff3d3..ab25def6bf4a6 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftInvocation.h
+++ b/tools/SourceKit/lib/SwiftLang/SwiftInvocation.h
@@ -26,7 +26,7 @@ namespace SourceKit {
 
 /// Encompasses an invocation for getting an AST. This is used to control AST
 /// sharing among different requests.
-class SwiftInvocation : public swift::ThreadSafeRefCountedBase<SwiftInvocation> {
+class SwiftInvocation : public llvm::ThreadSafeRefCountedBase<SwiftInvocation> {
 public:
   ~SwiftInvocation();
 
diff --git a/unittests/Basic/CMakeLists.txt b/unittests/Basic/CMakeLists.txt
index 401dd043eb29b..e254411857a4d 100644
--- a/unittests/Basic/CMakeLists.txt
+++ b/unittests/Basic/CMakeLists.txt
@@ -19,6 +19,7 @@ add_swift_unittest(SwiftBasicTests
   SourceManager.cpp
   StringExtrasTest.cpp
   SuccessorMapTest.cpp
+  ThreadSafeRefCntPointerTests.cpp
   TreeScopedHashTableTests.cpp
   Unicode.cpp
   ${generated_tests}
diff --git a/unittests/Basic/ThreadSafeRefCntPointerTests.cpp b/unittests/Basic/ThreadSafeRefCntPointerTests.cpp
new file mode 100644
index 0000000000000..434be42d0a959
--- /dev/null
+++ b/unittests/Basic/ThreadSafeRefCntPointerTests.cpp
@@ -0,0 +1,51 @@
+#include "swift/Basic/ThreadSafeRefCounted.h"
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "gtest/gtest.h"
+
+using llvm::IntrusiveRefCntPtr;
+
+struct TestRelease : llvm::ThreadSafeRefCountedBase<TestRelease> {
+  bool &destroy;
+  TestRelease(bool &destroy) : destroy(destroy) {}
+  ~TestRelease() { destroy = true; }
+};
+
+TEST(ThreadSafeRefCountedBase, ReleaseSimple) {
+  bool destroyed = false;
+  {
+    IntrusiveRefCntPtr<TestRelease> ref = new TestRelease(destroyed);
+  }
+  EXPECT_TRUE(destroyed);
+}
+TEST(ThreadSafeRefCountedBase, Release) {
+  bool destroyed = false;
+  {
+    IntrusiveRefCntPtr<TestRelease> ref = new TestRelease(destroyed);
+    ref->Retain();
+    ref->Release();
+  }
+  EXPECT_TRUE(destroyed);
+}
+
+struct TestReleaseVPTR : swift::ThreadSafeRefCountedBaseVPTR {
+  bool &destroy;
+  TestReleaseVPTR(bool &destroy) : destroy(destroy) {}
+  virtual ~TestReleaseVPTR() { destroy = true; }
+};
+
+TEST(ThreadSafeRefCountedBaseVPTR, ReleaseSimple) {
+  bool destroyed = false;
+  {
+    IntrusiveRefCntPtr<TestReleaseVPTR> ref = new TestReleaseVPTR(destroyed);
+  }
+  EXPECT_TRUE(destroyed);
+}
+TEST(ThreadSafeRefCountedBaseVPTR, Release) {
+  bool destroyed = false;
+  {
+    IntrusiveRefCntPtr<TestReleaseVPTR> ref = new TestReleaseVPTR(destroyed);
+    ref->Retain();
+    ref->Release();
+  }
+  EXPECT_TRUE(destroyed);
+}