Index: lib/CodeGen/CGExprScalar.cpp
===================================================================
--- lib/CodeGen/CGExprScalar.cpp
+++ lib/CodeGen/CGExprScalar.cpp
@@ -1411,7 +1411,10 @@
   }
   case CK_AddressSpaceConversion: {
     Value *Src = Visit(const_cast<Expr*>(E));
-    return Builder.CreateAddrSpaceCast(Src, ConvertType(DestTy));
+    // Since target may map different address spaces in AST to the same address
+    // space, an address space conversion may end up as a bitcast.
+    return Builder.CreatePointerBitCastOrAddrSpaceCast(Src,
+                                                       ConvertType(DestTy));
   }
   case CK_AtomicToNonAtomic:
   case CK_NonAtomicToAtomic:
Index: test/CodeGenOpenCL/address-spaces-conversions.cl
===================================================================
--- test/CodeGenOpenCL/address-spaces-conversions.cl
+++ test/CodeGenOpenCL/address-spaces-conversions.cl
@@ -1,4 +1,6 @@
 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -ffake-address-space-map -cl-std=CL2.0 -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -O0 -cl-std=CL2.0 -emit-llvm -o - | FileCheck --check-prefix=CHECK-NOFAKE %s
+// When -ffake-address-space-map is not used, all addr space mapped to 0 for x86_64.
 
 // test that we generate address space casts everywhere we need conversions of
 // pointers to different address spaces
@@ -7,16 +9,33 @@
   int var_priv;
   arg_gen = arg_glob; // implicit cast global -> generic
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(4)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   arg_gen = &var_priv; // implicit cast with obtaining adr, private -> generic
   // CHECK: %{{[0-9]+}} = addrspacecast i32* %var_priv to i32 addrspace(4)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   arg_glob = (global int *)arg_gen; // explicit cast
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(4)* %{{[0-9]+}} to i32 addrspace(1)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   global int *var_glob =
       (global int *)arg_glob; // explicit cast in the same address space
   // CHECK-NOT: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(1)*
+  // CHECK-NOFAKE-NOT: addrspacecast
+
   var_priv = arg_gen - arg_glob; // arithmetic operation
   // CHECK: %{{.*}} = ptrtoint i32 addrspace(4)* %{{.*}} to i64
   // CHECK: %{{.*}} = ptrtoint i32 addrspace(1)* %{{.*}} to i64
+  // CHECK-NOFAKE: %{{.*}} = ptrtoint i32* %{{.*}} to i64
+  // CHECK-NOFAKE: %{{.*}} = ptrtoint i32* %{{.*}} to i64
+
   var_priv = arg_gen > arg_glob; // comparison
   // CHECK: %{{[0-9]+}} = addrspacecast i32 addrspace(1)* %{{[0-9]+}} to i32 addrspace(4)*
+
+  generic void *var_gen_v = arg_glob;
+  // CHECK: addrspacecast
+  // CHECK-NOT: bitcast
+  // CHECK-NOFAKE: bitcast
+  // CHECK-NOFAKE-NOT: addrspacecast
 }