Use the struct builder for unions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@77732 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 3f34225..bf81236 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -583,6 +583,8 @@
   }
 
   llvm::Constant *EmitUnionInitialization(InitListExpr *ILE) {
+    return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
+
     const llvm::Type *Ty = ConvertType(ILE->getType());
 
     FieldDecl* curField = ILE->getInitializedFieldInUnion();