diff --git a/include/llvm/Constants.h b/include/llvm/Constants.h
index dd85b43bc7a..e8ded56dcff 100644
--- a/include/llvm/Constants.h
+++ b/include/llvm/Constants.h
@@ -358,6 +358,12 @@ public:
   /// created as ConstantAggregateZero objects.
   virtual bool isNullValue() const { return false; }
 
+  /// This function will return true iff every element in this packed constant
+  /// is set to all ones.
+  /// @returns true iff this constant's emements are all set to all ones.
+  /// @brief Determine if the value is all ones.
+  virtual bool isAllOnesValue() const;
+
   virtual void destroyConstant();
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index c2332c6e614..50b89822782 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -1166,6 +1166,22 @@ void ConstantPacked::destroyConstant() {
   destroyConstantImpl();
 }
 
+/// This function will return true iff every element in this packed constant
+/// is set to all ones.
+/// @returns true iff this constant's emements are all set to all ones.
+/// @brief Determine if the value is all ones.
+bool ConstantPacked::isAllOnesValue() const {
+  // Check out first element.
+  const Constant *Elt = getOperand(0);
+  const ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+  if (!CI || !CI->isAllOnesValue()) return false;
+  // Then make sure all remaining elements point to the same value.
+  for (unsigned I = 1, E = getNumOperands(); I < E; ++I) {
+    if (getOperand(I) != Elt) return false;
+  }
+  return true;
+}
+
 //---- ConstantPointerNull::get() implementation...
 //