diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 5e9d73f082fc8948dd8b48e9431aa0bf4d3b9ae7..0607a5157a6fc182e7627e4be7c31939a365e731 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -3637,6 +3637,16 @@ void CGDebugInfo::EmitUsingDecl(const UsingDecl &UD) {
   // Emitting one decl is sufficient - debuggers can detect that this is an
   // overloaded name & provide lookup for all the overloads.
   const UsingShadowDecl &USD = **UD.shadow_begin();
+
+  // FIXME: Skip functions with undeduced auto return type for now since we
+  // don't currently have the plumbing for separate declarations & definitions
+  // of free functions and mismatched types (auto in the declaration, concrete
+  // return type in the definition)
+  if (const auto *FD = dyn_cast<FunctionDecl>(USD.getUnderlyingDecl()))
+    if (const auto *AT =
+            FD->getType()->getAs<FunctionProtoType>()->getContainedAutoType())
+      if (AT->getDeducedType().isNull())
+        return;
   if (llvm::DINode *Target =
           getDeclarationOrDefinition(USD.getUnderlyingDecl()))
     DBuilder.createImportedDeclaration(
diff --git a/test/CodeGenCXX/debug-info-cxx1y.cpp b/test/CodeGenCXX/debug-info-cxx1y.cpp
index faf29d3ed11b4cc07053e243aa1d6063660eda2e..36b3e09180c61a6cc43e77f5ac1efa6ccd2c71be 100644
--- a/test/CodeGenCXX/debug-info-cxx1y.cpp
+++ b/test/CodeGenCXX/debug-info-cxx1y.cpp
@@ -1,16 +1,25 @@
 // RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm-only -std=c++14 -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
 
+// CHECK: imports: [[IMPS:![0-9]*]]
 // CHECK: [[EMPTY:![0-9]*]] = !{}
+
 // CHECK: [[FOO:![0-9]+]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo",
 // CHECK-SAME:             elements: [[EMPTY]]
-// FIXME: The context of this definition should be the CU/file scope, not the class.
-// CHECK: !DISubprogram(name: "func", {{.*}} scope: [[FOO]]
+
+// CHECK: [[IMPS]] = !{[[IMP:![0-9]*]]}
+// CHECK: [[IMP]] = !DIImportedEntity(
+// CHECK-SAME: entity: [[F3:![0-9]*]]
+// CHECK: [[F3]] = distinct !DISubprogram(name: "f3"
 // CHECK-SAME:          type: [[SUBROUTINE_TYPE:![0-9]*]]
-// CHECK-SAME:          isDefinition: true
-// CHECK-SAME:          declaration: [[FUNC_DECL:![0-9]*]]
 // CHECK: [[SUBROUTINE_TYPE]] = !DISubroutineType(types: [[TYPE_LIST:![0-9]*]])
 // CHECK: [[TYPE_LIST]] = !{[[INT:![0-9]*]]}
 // CHECK: [[INT]] = !DIBasicType(name: "int"
+
+// FIXME: The context of this definition should be the CU/file scope, not the class.
+// CHECK: !DISubprogram(name: "func", {{.*}} scope: [[FOO]]
+// CHECK-SAME:          type: [[SUBROUTINE_TYPE]]
+// CHECK-SAME:          isDefinition: true
+// CHECK-SAME:          declaration: [[FUNC_DECL:![0-9]*]]
 // CHECK: [[FUNC_DECL]] = !DISubprogram(name: "func",
 // CHECK-SAME:                          scope: [[FOO]]
 // CHECK-SAME:                          type: [[SUBROUTINE_TYPE]]
@@ -25,3 +34,12 @@ foo f;
 auto foo::func() {
   return 1;
 }
+
+namespace ns {
+auto f2();
+auto f3() {
+  return 0;
+}
+}
+using ns::f2;
+using ns::f3;