diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 1a4e5a790d00..a7a76af91ab7 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -1072,6 +1072,9 @@ void CXXRecordDecl::addedMember(Decl *D) {
     }
 
     if (T->isHyperobjectType()) {
+      // Do not allow braced list initialization, which would
+      // suppress hyperobject registration.
+      data().Aggregate = false;
       data().HasIrrelevantDestructor = false;
       data().HasTrivialSpecialMembers &= ~SMF_Destructor;
       data().HasTrivialSpecialMembersForCall &= ~SMF_Destructor;
diff --git a/clang/test/Cilk/hyper-init-error.cpp b/clang/test/Cilk/hyper-init-error.cpp
new file mode 100644
index 000000000000..38c608c85bf5
--- /dev/null
+++ b/clang/test/Cilk/hyper-init-error.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 %s -fopencilk -verify -fsyntax-only
+extern void id(void *), reduce(void *, void *);
+struct one_hyperobject {
+  // expected-note@-1{{implicit copy}}
+  // expected-note@-2{{implicit move}}
+  // expected-note@-3{{implicit default}}
+  int _Hyperobject(id, reduce) field;
+};
+
+// braced initializer lists do not work
+one_hyperobject h1 = {-1};
+// expected-error@-1{{no matching constructor for initialization}}
+
+one_hyperobject h2;