Index: cfe/trunk/lib/Sema/SemaCast.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaCast.cpp
+++ cfe/trunk/lib/Sema/SemaCast.cpp
@@ -1955,6 +1955,12 @@
   return Result.isUsable();
 }
 
+static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) {
+  return SrcType->isPointerType() && DestType->isPointerType() &&
+         SrcType->getAs<PointerType>()->getPointeeType().getAddressSpace() !=
+             DestType->getAs<PointerType>()->getPointeeType().getAddressSpace();
+}
+
 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
                                         QualType DestType, bool CStyle,
                                         SourceRange OpRange,
@@ -2198,6 +2204,8 @@
     } else {
       Kind = CK_BitCast;
     }
+  } else if (IsAddressSpaceConversion(SrcType, DestType)) {
+    Kind = CK_AddressSpaceConversion;
   } else {
     Kind = CK_BitCast;
   }
Index: cfe/trunk/lib/Sema/SemaOverload.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp
+++ cfe/trunk/lib/Sema/SemaOverload.cpp
@@ -3150,6 +3150,15 @@
       = PreviousToQualsIncludeConst && ToQuals.hasConst();
   }
 
+  // Allows address space promotion by language rules implemented in
+  // Type::Qualifiers::isAddressSpaceSupersetOf.
+  Qualifiers FromQuals = FromType.getQualifiers();
+  Qualifiers ToQuals = ToType.getQualifiers();
+  if (!ToQuals.isAddressSpaceSupersetOf(FromQuals) &&
+      !FromQuals.isAddressSpaceSupersetOf(ToQuals)) {
+    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: cfe/trunk/test/CodeGenCXX/address-space-cast.cpp
===================================================================
--- cfe/trunk/test/CodeGenCXX/address-space-cast.cpp
+++ cfe/trunk/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_cast(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);
+}