[C++11] Add 'override' keyword to IR library.

llvm-svn: 202939
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 7a3cdb9..dc77d29 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -225,9 +225,9 @@
   MDNode *get() const {
     return cast_or_null<MDNode>(getValPtr());
   }
-  
-  virtual void deleted();
-  virtual void allUsesReplacedWith(Value *VNew);
+
+  void deleted() override;
+  void allUsesReplacedWith(Value *VNew) override;
 };
   
 class LLVMContextImpl {