1 files changed, 18 insertions, 8 deletions
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 128809175e2..d2a4a0979d1 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -4631,7 +4631,10 @@ static void TryReferenceInitializationCore(Sema &S,
   //     - Otherwise, the reference shall be an lvalue reference to a
   //       non-volatile const type (i.e., cv1 shall be const), or the reference
   //       shall be an rvalue reference.
-  if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile())) {
+  //       For address spaces, we interpret this to mean that an addr space
+  //       of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
+  if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
+                       T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
     if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
       Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
     else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
@@ -4640,7 +4643,10 @@ static void TryReferenceInitializationCore(Sema &S,
                                   ConvOvlResult);
     else if (!InitCategory.isLValue())
       Sequence.SetFailed(
-          InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
+          T1Quals.isAddressSpaceSupersetOf(T2Quals)
+              ? InitializationSequence::
+                    FK_NonConstLValueReferenceBindingToTemporary
+              : InitializationSequence::FK_ReferenceInitDropsQualifiers);
     else {
       InitializationSequence::FailureKind FK;
       switch (RefRelationship) {
@@ -8521,12 +8527,16 @@ bool InitializationSequence::Diagnose(Sema &S,
     Qualifiers DroppedQualifiers =
         SourceType.getQualifiers() - NonRefType.getQualifiers();
 
-    S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
-      << NonRefType
-      << SourceType
-      << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
-      << DroppedQualifiers.getCVRQualifiers()
-      << Args[0]->getSourceRange();
+    if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
+            SourceType.getQualifiers()))
+      S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
+          << NonRefType << SourceType << 1 /*addr space*/
+          << Args[0]->getSourceRange();
+    else
+      S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
+          << NonRefType << SourceType << 0 /*cv quals*/
+          << Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
+          << DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
     break;
   }