Add CK_DerivedToBase and use it PerformObjectMemberConversion.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@77652 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index b095eb7..eedbdce 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -2727,7 +2727,7 @@
       // Perform the conversion.
       // FIXME: Binding to a subobject of the lvalue is going to require more
       // AST annotation than this.
-      ImpCastExprToType(Init, T1, /*isLvalue=*/true);    
+      ImpCastExprToType(Init, T1, CastExpr::CK_Unknown, /*isLvalue=*/true);    
     }
   }
 
@@ -2786,7 +2786,7 @@
         // Perform the conversion.
         // FIXME: Binding to a subobject of the lvalue is going to require more
         // AST annotation than this.
-        ImpCastExprToType(Init, T1, /*isLvalue=*/true);
+        ImpCastExprToType(Init, T1, CastExpr::CK_Unknown, /*isLvalue=*/true);
       }
       break;
 
@@ -2874,7 +2874,7 @@
     } else {
       // FIXME: Binding to a subobject of the rvalue is going to require more
       // AST annotation than this.
-      ImpCastExprToType(Init, T1, /*isLvalue=*/false);
+      ImpCastExprToType(Init, T1, CastExpr::CK_Unknown, /*isLvalue=*/false);
     }
     return false;
   }