Index: clang/lib/CodeGen/CGClass.cpp
===================================================================
--- clang/lib/CodeGen/CGClass.cpp
+++ clang/lib/CodeGen/CGClass.cpp
@@ -2502,6 +2502,8 @@
 
   // Apply the offsets.
   Address VTableField = LoadCXXThisAddress();
+  unsigned ThisAddrSpace =
+      VTableField.getPointer()->getType()->getPointerAddressSpace();
 
   if (!NonVirtualOffset.isZero() || VirtualOffset)
     VTableField = ApplyNonVirtualAndVirtualOffset(
@@ -2516,12 +2518,11 @@
       llvm::FunctionType::get(CGM.Int32Ty, /*isVarArg=*/true)
           ->getPointerTo(ProgAS)
           ->getPointerTo(GlobalsAS);
-  // vtable field is is derived from `this` pointer, therefore it should be in
-  // default address space.
-  VTableField = Builder.CreatePointerBitCastOrAddrSpaceCast(
-      VTableField, VTablePtrTy->getPointerTo());
-  VTableAddressPoint = Builder.CreatePointerBitCastOrAddrSpaceCast(
-      VTableAddressPoint, VTablePtrTy);
+  // vtable field is is derived from `this` pointer, therefore they should be in
+  // the same addr space. Note that this might not be LLVM address space 0.
+  VTableField = Builder.CreateBitCast(VTableField,
+                                      VTablePtrTy->getPointerTo(ThisAddrSpace));
+  VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
 
   llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
   TBAAAccessInfo TBAAInfo = CGM.getTBAAVTablePtrAccessInfo(VTablePtrTy);