diff --git a/include/llvm/ADT/IntrusiveRefCntPtr.h b/include/llvm/ADT/IntrusiveRefCntPtr.h
index 592e42f7adc..2f6fd2bd559 100644
--- a/include/llvm/ADT/IntrusiveRefCntPtr.h
+++ b/include/llvm/ADT/IntrusiveRefCntPtr.h
@@ -42,15 +42,15 @@ namespace llvm {
 //===----------------------------------------------------------------------===//
   template <class Derived>
   class RefCountedBase {
-    unsigned ref_cnt;
+    mutable unsigned ref_cnt;
 
   public:
     RefCountedBase() : ref_cnt(0) {}
 
-    void Retain() { ++ref_cnt; }
-    void Release() {
+    void Retain() const { ++ref_cnt; }
+    void Release() const {
       assert (ref_cnt > 0 && "Reference count is already zero.");
-      if (--ref_cnt == 0) delete static_cast<Derived*>(this);
+      if (--ref_cnt == 0) delete static_cast<const Derived*>(this);
     }
   };
 
@@ -63,14 +63,14 @@ namespace llvm {
 ///  attempting to do this will produce a compile error.
 //===----------------------------------------------------------------------===//
   class RefCountedBaseVPTR {
-    unsigned ref_cnt;
+    mutable unsigned ref_cnt;
 
   protected:
     RefCountedBaseVPTR() : ref_cnt(0) {}
     virtual ~RefCountedBaseVPTR() {}
 
-    void Retain() { ++ref_cnt; }
-    void Release() {
+    void Retain() const { ++ref_cnt; }
+    void Release() const {
       assert (ref_cnt > 0 && "Reference count is already zero.");
       if (--ref_cnt == 0) delete this;
     }