Index: lib/Sema/Sema.cpp
===================================================================
--- lib/Sema/Sema.cpp
+++ lib/Sema/Sema.cpp
@@ -394,6 +394,14 @@
   if (ExprTy == TypeTy)
     return E;
 
+  // In the event an address space cast is requested, the kind passed from the
+  // caller should not be CK_NoOp.
+  assert((Kind != CK_NoOp ||
+          !(ExprTy->isPointerType() && TypeTy->isPointerType() &&
+            ExprTy->getPointeeType().getAddressSpace() !=
+                TypeTy->getPointeeType().getAddressSpace())) &&
+         "NoOp is not a valid kind for and address cast");
+
   if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
     if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
       ImpCast->setType(Ty);
Index: lib/Sema/SemaCast.cpp
===================================================================
--- lib/Sema/SemaCast.cpp
+++ lib/Sema/SemaCast.cpp
@@ -2040,7 +2040,7 @@
       << OpRange;
     return TC_Success;
   }
-  
+
   // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
   //   a pointer to an object of different type.
   // Void pointers are not specified, but supported by every compiler out there.
@@ -2108,6 +2108,22 @@
       return;
     }
 
+  // If we are casting pointers, we need to check whether this refers to an
+  // address space cast.
+  if (DestType->isPointerType() && SrcExpr.get()->getType()->isPointerType()) {
+    QualType DTy =
+        Self.getASTContext().getCanonicalType(DestType->getPointeeType());
+    QualType STy = Self.getASTContext().getCanonicalType(
+        SrcExpr.get()->getType()->getPointeeType());
+    // If the pointer point to the same type in different address spaces, this
+    // is an address-space cast.
+    if (STy.getTypePtr() == DTy.getTypePtr() &&
+        STy.getAddressSpace() != DTy.getAddressSpace()) {
+      Kind = CK_AddressSpaceConversion;
+      return;
+    }
+  }
+
   // C++ [expr.cast]p5: The conversions performed by
   //   - a const_cast,
   //   - a static_cast,
Index: test/CodeGen/address-space-explicit-cast.c
===================================================================
--- /dev/null
+++ test/CodeGen/address-space-explicit-cast.c
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -emit-llvm -o - -x c %s | FileCheck -check-prefix=CHECK %s
+// RUN: %clang_cc1 -emit-llvm -o - -x c++ %s | FileCheck -check-prefix=CHECK-CXX %s
+
+typedef __attribute__((address_space(1))) char *AddrSpaceCharType;
+
+// CHECK-LABEL: @foo()
+// CHECK-CXX-LABEL: @_Z3foov()
+void foo() {
+  // CHECK: %p = alloca i8 addrspace(1)*
+  // CHECK-CXX: %p = alloca i8 addrspace(1)*
+  AddrSpaceCharType p;
+
+  // CHECK: store i8 addrspace(1)* addrspacecast ({{.*}} to i8 addrspace(1)*), i8 addrspace(1)** %p
+  // CHECK-CXX: store i8 addrspace(1)* addrspacecast ({{.*}} to i8 addrspace(1)*), i8 addrspace(1)** %p
+  p = (AddrSpaceCharType) "a";
+}