Index: include/llvm/ADT/BitVector.h
===================================================================
--- include/llvm/ADT/BitVector.h
+++ include/llvm/ADT/BitVector.h
@@ -295,6 +295,23 @@
     return *this;
   }
 
+  /// Set bit \p Idx to true. This function allows BitVector to be used in
+  /// contexts expecting std::set/DenseSet like API.
+  std::pair<reference, bool> insert(unsigned Idx) {
+    reference ref(*this, Idx);
+    bool Res = !ref;
+    ref = true;
+    return std::make_pair(ref, Res);
+  }
+
+  /// Clear bit \p Idx. This function allows BitVector to be used in contexts
+  /// expecting std::set/DenseSet like API.
+  bool erase(unsigned Idx) {
+    bool Res = test(Idx);
+    reset(Idx);
+    return Res;
+  }
+
   BitVector &flip() {
     for (unsigned i = 0; i < NumBitWords(size()); ++i)
       Bits[i] = ~Bits[i];