Index: lib/Sema/SemaCUDA.cpp
===================================================================
--- lib/Sema/SemaCUDA.cpp
+++ lib/Sema/SemaCUDA.cpp
@@ -611,8 +611,12 @@
   // emitted, because (say) the definition could include "inline".
   FunctionDecl *Def = FD->getDefinition();
 
+  CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(FD);
+
   if (Def &&
-      !isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(Def)))
+      !isDiscardableGVALinkage(
+          S.getASTContext().GetGVALinkageForFunction(Def)) &&
+      !(MD && MD->isDefaulted()))
     return true;
 
   // Otherwise, the function is known-emitted if it's in our set of
Index: test/SemaCUDA/default-ctor.cu
===================================================================
--- /dev/null
+++ test/SemaCUDA/default-ctor.cu
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -std=c++11 -triple nvptx64-nvidia-cuda -fsyntax-only -fcuda-is-device -verify %s
+
+#define __host__ __attribute__((host))
+#define __device__ __attribute__((device))
+
+struct Base {
+  virtual ~Base(); // expected-note {{'~Base' declared here}}
+};
+
+struct Unused : public Base {
+  Unused();
+};
+
+// Unused defaulted constructor should not cause diagnostics.
+Unused::Unused() = default;
+
+struct Used : public Base // expected-note {{'~Used' declared here}}
+{
+  Used();
+};
+
+Used::Used() = default; // expected-error {{reference to __host__ function '~Base' in __host__ __device__ function}}
+
+__device__ void f() {
+  Used x; // expected-error {{reference to __host__ function '~Used' in __device__ function}}
+          // expected-note@-1 {{called by 'f'}}
+}