Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -821,7 +821,7 @@
   for (unsigned I = 0; I != NumParams; ++I) {
     (void)CheckCXXDefaultArgExpr(Attr->getLocation(), Ctor,
                                    Ctor->getParamDecl(I));
-    DiscardCleanupsInEvaluationContext();
+    CleanupVarDeclMarking();
   }
 }
 
Index: clang/test/CodeGenCXX/dllexport-ctor-closure.cpp
===================================================================
--- clang/test/CodeGenCXX/dllexport-ctor-closure.cpp
+++ clang/test/CodeGenCXX/dllexport-ctor-closure.cpp
@@ -88,3 +88,10 @@
 // CHECK-LABEL: define linkonce_odr dso_local x86_thiscallcc void @"??1HasImplicitDtor1@@QAE@XZ"
 // CHECK-LABEL: define weak_odr dso_local dllexport x86_thiscallcc void @"??_FCtorClosureOutOfLine@@QAEXXZ"
 // CHECK-LABEL: define linkonce_odr dso_local x86_thiscallcc void @"??1HasImplicitDtor2@@QAE@XZ"
+
+struct SomeStruct {};
+constexpr SomeStruct kConstexprStruct;
+struct __declspec(dllexport) ConstexprDefaultArg {
+  ConstexprDefaultArg(SomeStruct = kConstexprStruct) {}
+};
+// CHECK-LABEL: define weak_odr dso_local dllexport x86_thiscallcc void @"??_FConstexprDefaultArg@@QAEXXZ"