diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 74fd794..537daf9 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -997,7 +997,7 @@
 
   // If we're in C++, compute the base subobject type.
   llvm::StructType *BaseTy = 0;
-  if (isa<CXXRecordDecl>(D)) {
+  if (isa<CXXRecordDecl>(D) && !D->isUnion()) {
     BaseTy = Builder.BaseSubobjectType;
     if (!BaseTy) BaseTy = Ty;
   }
diff --git a/test/CodeGenCXX/empty-union.cpp b/test/CodeGenCXX/empty-union.cpp
index 118a0d2..7f3e6cc 100644
--- a/test/CodeGenCXX/empty-union.cpp
+++ b/test/CodeGenCXX/empty-union.cpp
@@ -1,10 +1,7 @@
 // RUN: %clang_cc1 -emit-llvm -o - %s
 
 union sigval { };
+union sigval Test1;
 
-union sigval sigev_value;
-
-int main()
-{
-  return sizeof(sigev_value);
-}
+union NonPODUnion { ~NonPODUnion(); };
+union NonPODUnion Test2;