diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index b2e1d20..1e71a62 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -2984,8 +2984,15 @@
   return mangleSubstitution(reinterpret_cast<uintptr_t>(ND));
 }
 
+/// \brief Determine whether the given type has any qualifiers that are
+/// relevant for substitutions.
+static bool hasMangledSubstitutionQualifiers(QualType T) {
+  Qualifiers Qs = T.getQualifiers();
+  return Qs.getCVRQualifiers() || Qs.hasAddressSpace();
+}
+
 bool CXXNameMangler::mangleSubstitution(QualType T) {
-  if (!T.getCVRQualifiers()) {
+  if (!hasMangledSubstitutionQualifiers(T)) {
     if (const RecordType *RT = T->getAs<RecordType>())
       return mangleSubstitution(RT->getDecl());
   }
@@ -3171,7 +3178,7 @@
 }
 
 void CXXNameMangler::addSubstitution(QualType T) {
-  if (!T.getCVRQualifiers()) {
+  if (!hasMangledSubstitutionQualifiers(T)) {
     if (const RecordType *RT = T->getAs<RecordType>()) {
       addSubstitution(RT->getDecl());
       return;