add a helper method

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30452 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Instructions.h

@@ -498,6 +498,11 @@ public:
     : UnaryInstruction(Ty, Cast, S, Name, InsertAtEnd) {
   }
 
+  /// isTruncIntCast - Return true if this is a truncating integer cast
+  /// instruction, e.g. a cast from long to uint.
+  bool isTruncIntCast() const;
+  
+  
   virtual CastInst *clone() const;
 
   // Methods for support type inquiry through isa, cast, and dyn_cast: