diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 7c2918d17f76..77f1b9b0d707 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5896,7 +5896,7 @@ def note_deleted_special_member_class_subobject : Note<
 def note_deleted_default_ctor_uninit_field : Note<
   "%select{default constructor of|constructor inherited by}0 "
   "%1 is implicitly deleted because field %2 of "
-  "%select{reference|const-qualified}4 type %3 would not be initialized">;
+  "%select{reference|const-qualified|reducer}4 type %3 would not be initialized">;
 def note_deleted_default_ctor_all_const : Note<
   "%select{default constructor of|constructor inherited by}0 "
   "%1 is implicitly deleted because all "
diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 137c36101244..44b70b24cacb 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -1088,8 +1088,8 @@ void CXXRecordDecl::addedMember(Decl *D) {
       // suppress hyperobject registration.
       data().Aggregate = false;
       data().HasIrrelevantDestructor = false;
-      data().HasTrivialSpecialMembers &= ~SMF_Destructor;
-      data().HasTrivialSpecialMembersForCall &= ~SMF_Destructor;
+      data().HasTrivialSpecialMembers &= ~SMF_All;
+      data().HasTrivialSpecialMembersForCall &= ~SMF_All;
     }
 
     if (!Field->hasInClassInitializer() && !Field->isMutable()) {
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index e8cf41007cc4..a655248511ec 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9595,6 +9595,12 @@ bool SpecialMemberDeletionInfo::shouldDeleteForField(FieldDecl *FD) {
           << !!ICI << MD->getParent() << FD << FieldType << /*Reference*/0;
       return true;
     }
+    if (FieldType->isHyperobjectType() && !FD->hasInClassInitializer()) {
+      if (Diagnose)
+        S.Diag(FD->getLocation(), diag::note_deleted_default_ctor_uninit_field)
+          << !!ICI << MD->getParent() << FD << FieldType << /*Reducer*/2;
+      return true;
+    }
     // C++11 [class.ctor]p5 (modified by DR2394): any non-variant non-static
     // data member of const-qualified type (or array thereof) with no
     // brace-or-equal-initializer is not const-default-constructible.
diff --git a/clang/test/Cilk/hyper-errors.cpp b/clang/test/Cilk/hyper-errors.cpp
index 664df5983143..e5a45d155d18 100644
--- a/clang/test/Cilk/hyper-errors.cpp
+++ b/clang/test/Cilk/hyper-errors.cpp
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 %s -x c++ -fopencilk -verify -fsyntax-only
-struct C { int _Hyperobject c; };
+struct C { int _Hyperobject c = 0; };
 struct C _Hyperobject c; // expected-error{{type 'struct C', which contains a hyperobject, may not be a hyperobject}}
 long _Hyperobject d; // expected-note{{previous definition}}
 void f() {
diff --git a/clang/test/Cilk/hyper-init-error.cpp b/clang/test/Cilk/hyper-init-error.cpp
index 38c608c85bf5..bc54fb0fa29d 100644
--- a/clang/test/Cilk/hyper-init-error.cpp
+++ b/clang/test/Cilk/hyper-init-error.cpp
@@ -1,14 +1,22 @@
 // RUN: %clang_cc1 %s -fopencilk -verify -fsyntax-only
 extern void id(void *), reduce(void *, void *);
-struct one_hyperobject {
+struct uninit_hyperobject {
   // expected-note@-1{{implicit copy}}
   // expected-note@-2{{implicit move}}
   // expected-note@-3{{implicit default}}
   int _Hyperobject(id, reduce) field;
+  // expected-note@-1{{would not be initialized}}
 };
 
 // braced initializer lists do not work
-one_hyperobject h1 = {-1};
+uninit_hyperobject h1 = {-1};
 // expected-error@-1{{no matching constructor for initialization}}
 
-one_hyperobject h2;
+uninit_hyperobject h2;
+// expected-error@-1{{implicitly-deleted default constructor}}
+
+struct init_hyperobject {
+  int _Hyperobject(id, reduce) field = 0;
+};
+
+init_hyperobject h3;
diff --git a/clang/test/Cilk/hyper-register.cpp b/clang/test/Cilk/hyper-register.cpp
index cedddc1e6843..a39e6050b08c 100644
--- a/clang/test/Cilk/hyper-register.cpp
+++ b/clang/test/Cilk/hyper-register.cpp
@@ -3,7 +3,7 @@
 struct S {
   static void identity(void *);
   static void reduce(void *, void *);
-  int _Hyperobject(identity, reduce) member;
+  int _Hyperobject(identity, reduce) member = 0;
   S();
   ~S();
 };
diff --git a/clang/test/Cilk/hyper-template-errors.cpp b/clang/test/Cilk/hyper-template-errors.cpp
index 300dc90acf6e..b456d8f8434a 100644
--- a/clang/test/Cilk/hyper-template-errors.cpp
+++ b/clang/test/Cilk/hyper-template-errors.cpp
@@ -7,7 +7,8 @@ struct reducer
  // expected-error@-1{{type 'long _Hyperobject', which contains a hyperobject, may not be a hyperobject}}
  // expected-error@-2{{type 'reducer<char>', which contains a hyperobject, may not be a hyperobject}}
  // expected-error@-3{{type 'wrap<int _Hyperobject>', which contains a hyperobject, may not be a hyperobject}}
-  int _Hyperobject value2;
+  int _Hyperobject value2 = 0;
+  reducer();
 };
 
 reducer<long _Hyperobject> r_hl; // expected-note{{in instantiation}}