Fix some clang warnings.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128272 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 9ce98b7..2c0bcc2 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -770,7 +770,7 @@
          return APValue();
        Result = APValue(F);
     } else {
-      return false;
+      return APValue();
     }
 
     // Splat and create vector APValue.
@@ -782,7 +782,7 @@
       return Visit(const_cast<Expr*>(SE));
 
     if (!SETy->isIntegerType())
-      return false;
+      return APValue();
 
     APSInt Init;
     if (!EvaluateInteger(SE, Init, Info))
@@ -808,7 +808,7 @@
   case CK_NoOp:
     return Visit(const_cast<Expr*>(SE));
   default:
-    return false;
+    return APValue();
   }
 }