1 files changed, 6 insertions, 2 deletions
diff --git a/include/llvm/ADT/SmallBitVector.h b/include/llvm/ADT/SmallBitVector.h
index 0922017ea61a..1e2f365b1040 100644
--- a/include/llvm/ADT/SmallBitVector.h
+++ b/include/llvm/ADT/SmallBitVector.h
@@ -54,7 +54,7 @@ class SmallBitVector {
   };
 
 public:
-  typedef unsigned size_type;
+  typedef unsigned size_type;
   // Encapsulation of a single bit.
   class reference {
     SmallBitVector &TheVector;
@@ -292,8 +292,12 @@ public:
   }
 
   SmallBitVector &set(unsigned Idx) {
-    if (isSmall())
+    if (isSmall()) {
+      assert(Idx <= static_cast<unsigned>(
+                        std::numeric_limits<uintptr_t>::digits) &&
+             "undefined behavior");
       setSmallBits(getSmallBits() | (uintptr_t(1) << Idx));
+    }
     else
       getPointer()->set(Idx);
     return *this;