diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index b2d055bf3bb..538c31ed1f4 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -807,7 +807,7 @@ public:
   /// hasConstantValue - If the specified PHI node always merges together the 
   /// same value, return the value, otherwise return null.
   ///
-  Value *hasConstantValue(bool AllowNonDominatingInstruction = false);
+  Value *hasConstantValue(bool AllowNonDominatingInstruction = false) const;
   
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const PHINode *) { return true; }
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 035edb320a6..a3bd468fccf 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -135,7 +135,7 @@ void PHINode::resizeOperands(unsigned NumOps) {
 /// hasConstantValue - If the specified PHI node always merges together the same
 /// value, return the value, otherwise return null.
 ///
-Value *PHINode::hasConstantValue(bool AllowNonDominatingInstruction) {
+Value *PHINode::hasConstantValue(bool AllowNonDominatingInstruction) const {
   // If the PHI node only has one incoming value, eliminate the PHI node...
   if (getNumIncomingValues() == 1)
     return getIncomingValue(0);