Index: lib/Sema/SemaCast.cpp
===================================================================
--- lib/Sema/SemaCast.cpp
+++ lib/Sema/SemaCast.cpp
@@ -2163,6 +2163,13 @@
     } else {
       Kind = CK_BitCast;
     }
+  } else if (SrcType->isPointerType() && DestType->isPointerType() &&
+             SrcType->getAs<PointerType>()
+                     ->getPointeeType()
+                     .getAddressSpace() != DestType->getAs<PointerType>()
+                                               ->getPointeeType()
+                                               .getAddressSpace()) {
+    Kind = CK_AddressSpaceConversion;
   } else {
     Kind = CK_BitCast;
   }
Index: lib/Sema/SemaOverload.cpp
===================================================================
--- lib/Sema/SemaOverload.cpp
+++ lib/Sema/SemaOverload.cpp
@@ -3143,6 +3143,12 @@
       = PreviousToQualsIncludeConst && ToQuals.hasConst();
   }
 
+  // ToDo: Add more detailed control for implicit address space casting for
+  // OpenCL C++.
+  if (FromType.getAddressSpace() != ToType.getAddressSpace() &&
+      !getLangOpts().OpenCLCPlusPlus)
+    return false;
+
   // We are left with FromType and ToType being the pointee types
   // after unwrapping the original FromType and ToType the same number
   // of types. If we unwrapped any pointers, and if FromType and
Index: test/CodeGenCXX/address-space-cast.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/address-space-cast.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 %s -triple=amdgcn-amd-amdhsa -emit-llvm -o - | FileCheck %s
+
+#define __private__ __attribute__((address_space(5)))
+
+void func_pchar(__private__ char* x);
+
+void test(char *gen_ptr) {
+  // CHECK: %[[cast:.*]] = addrspacecast i8* %{{.*}} to i8 addrspace(5)*
+  // CHECK-NEXT: store i8 addrspace(5)* %[[cast]]
+  __private__ char* priv_ptr = (__private__ char*)gen_ptr;
+  
+  // CHECK: %[[cast:.*]] = addrspacecast i8* %{{.*}} to i8 addrspace(5)*
+  // CHECK-NEXT: call void @_Z10func_pcharPU3AS5c(i8 addrspace(5)* %[[cast]])
+  func_pchar((__private__ char*)gen_ptr);
+}