Index: lib/CodeGen/CGBuiltin.cpp
===================================================================
--- lib/CodeGen/CGBuiltin.cpp
+++ lib/CodeGen/CGBuiltin.cpp
@@ -2538,16 +2538,8 @@
     // Any calls now have event arguments passed.
     if (NumArgs >= 7) {
       llvm::Type *EventTy = ConvertType(getContext().OCLClkEventTy);
-      unsigned AS4 =
-          E->getArg(4)->getType()->isArrayType()
-              ? E->getArg(4)->getType().getAddressSpace()
-              : E->getArg(4)->getType()->getPointeeType().getAddressSpace();
-      llvm::Type *EventPtrAS4Ty =
-          EventTy->getPointerTo(CGM.getContext().getTargetAddressSpace(AS4));
-      unsigned AS5 =
-          E->getArg(5)->getType()->getPointeeType().getAddressSpace();
-      llvm::Type *EventPtrAS5Ty =
-          EventTy->getPointerTo(CGM.getContext().getTargetAddressSpace(AS5));
+      llvm::Type *EventPtrTy = EventTy->getPointerTo(
+          CGM.getContext().getTargetAddressSpace(LangAS::opencl_generic));
 
       llvm::Value *NumEvents = EmitScalarExpr(E->getArg(3));
       llvm::Value *EventList =
@@ -2555,12 +2547,16 @@
               ? EmitArrayToPointerDecay(E->getArg(4)).getPointer()
               : EmitScalarExpr(E->getArg(4));
       llvm::Value *ClkEvent = EmitScalarExpr(E->getArg(5));
+      // Convert to generic address space.
+      EventList = Builder.CreatePointerCast(EventList, EventPtrTy);
+      ClkEvent = Builder.CreatePointerCast(ClkEvent, EventPtrTy);
       llvm::Value *Block =
           Builder.CreateBitCast(EmitScalarExpr(E->getArg(6)), Int8PtrTy);
 
-      std::vector<llvm::Type *> ArgTys = {
-          QueueTy,       Int32Ty,       RangeTy,  Int32Ty,
-          EventPtrAS4Ty, EventPtrAS5Ty, Int8PtrTy};
+      std::vector<llvm::Type *> ArgTys = {QueueTy,  Int32Ty,    RangeTy,
+                                          Int32Ty,  EventPtrTy, EventPtrTy,
+                                          Int8PtrTy};
+
       std::vector<llvm::Value *> Args = {Queue,     Flags,    Range, NumEvents,
                                          EventList, ClkEvent, Block};
 
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -451,16 +451,20 @@
     Expr *Arg4 = TheCall->getArg(4);
     Expr *Arg5 = TheCall->getArg(5);
 
-    // Fith argument is always passed as pointers to clk_event_t.
-    if (!Arg4->getType()->getPointeeOrArrayElementType()->isClkEventT()) {
+    // Fifth argument is always passed as a pointer to clk_event_t.
+    if (!Arg4->isNullPointerConstant(S.Context,
+                                     Expr::NPC_ValueDependentIsNotNull) &&
+        !Arg4->getType()->getPointeeOrArrayElementType()->isClkEventT()) {
       S.Diag(TheCall->getArg(4)->getLocStart(),
              diag::err_opencl_enqueue_kernel_expected_type)
           << S.Context.getPointerType(S.Context.OCLClkEventTy);
       return true;
     }
 
-    // Sixth argument is always passed as pointers to clk_event_t.
-    if (!(Arg5->getType()->isPointerType() &&
+    // Sixth argument is always passed as a pointer to clk_event_t.
+    if (!Arg5->isNullPointerConstant(S.Context,
+                                     Expr::NPC_ValueDependentIsNotNull) &&
+        !(Arg5->getType()->isPointerType() &&
           Arg5->getType()->getPointeeType()->isClkEventT())) {
       S.Diag(TheCall->getArg(5)->getLocStart(),
              diag::err_opencl_enqueue_kernel_expected_type)
Index: test/CodeGenOpenCL/cl20-device-side-enqueue.cl
===================================================================
--- test/CodeGenOpenCL/cl20-device-side-enqueue.cl
+++ test/CodeGenOpenCL/cl20-device-side-enqueue.cl
@@ -31,10 +31,12 @@
 
   // CHECK: [[DEF_Q:%[0-9]+]] = load %opencl.queue_t*, %opencl.queue_t** %default_queue
   // CHECK: [[FLAGS:%[0-9]+]] = load i32, i32* %flags
+  // CHECK: [[WAIT_EVNT:%[0-9]+]] = addrspacecast %opencl.clk_event_t addrspace(1)** %event_wait_list to %opencl.clk_event_t addrspace(1)* addrspace(4)*
+  // CHECK: [[EVNT:%[0-9]+]] = addrspacecast %opencl.clk_event_t addrspace(1)** %clk_event to %opencl.clk_event_t addrspace(1)* addrspace(4)*
   // CHECK: [[NDR:%[0-9]+]] = load %opencl.ndrange_t*, %opencl.ndrange_t** %ndrange
   // CHECK: [[BL:%[0-9]+]] = bitcast <{ i8*, i32, i32, i8*, %struct.__block_descriptor addrspace(3)*, i32{{.*}}, i32{{.*}}, i32{{.*}} }>* %block3 to void ()*
   // CHECK: [[BL_I8:%[0-9]+]] = bitcast void ()* [[BL]] to i8*
-  // CHECK: call i32 @__enqueue_kernel_basic_events(%opencl.queue_t* [[DEF_Q]], i32 [[FLAGS]], %opencl.ndrange_t* [[NDR]], i32 2, %opencl.clk_event_t** %event_wait_list, %opencl.clk_event_t** %clk_event, i8* [[BL_I8]])
+  // CHECK: call i32 @__enqueue_kernel_basic_events(%opencl_queue_t addrspace(1)* [[DEF_Q]], i32 [[FLAGS]], %struct.ndrange_t* {{.*}}, i32 2, %opencl.clk_event_t{{.*}}* addrspace(4)* [[WAIT_EVNT]], %opencl.clk_event_t{{.*}}* addrspace(4)* [[EVNT]], i8* [[BL_I8]])
   enqueue_kernel(default_queue, flags, ndrange, 2, &event_wait_list, &clk_event,
                  ^(void) {
                    a[i] = b[i];
@@ -65,7 +67,9 @@
   // CHECK: [[FLAGS:%[0-9]+]] = load i32, i32* %flags
   // CHECK: [[NDR:%[0-9]+]] = load %opencl.ndrange_t*, %opencl.ndrange_t** %ndrange
   // CHECK: [[AD:%arraydecay[0-9]*]] = getelementptr inbounds [1 x %opencl.clk_event_t*], [1 x %opencl.clk_event_t*]* %event_wait_list2, i32 0, i32 0
-  // CHECK: call i32 (%opencl.queue_t*, i32, %opencl.ndrange_t*, i32, %opencl.clk_event_t**, %opencl.clk_event_t**, i8*, i32, ...) @__enqueue_kernel_events_vaargs(%opencl.queue_t* [[DEF_Q]], i32 [[FLAGS]], %opencl.ndrange_t* [[NDR]], i32 2, %opencl.clk_event_t** [[AD]], %opencl.clk_event_t** %clk_event, i8* bitcast ({ i8**, i32, i32, i8*, %struct.__block_descriptor addrspace(3)* }* @__block_literal_global{{(.[0-9]+)?}} to i8*), i32 1, i32 256)
+  // CHECK: [[WAIT_EVNT:%[0-9]+]] = addrspacecast %opencl.clk_event_t addrspace(1)** [[AD]] to %opencl.clk_event_t addrspace(1)* addrspace(4)*
+  // CHECK: [[EVNT:%[0-9]+]]  = addrspacecast %opencl.clk_event_t addrspace(1)** %clk_event to %opencl.clk_event_t addrspace(1)* addrspace(4)*
+  // CHECK: call i32 (%opencl_queue_t addrspace(1)*, i32, %struct.ndrange_t*, i32, %opencl.clk_event_t{{.*}}* addrspace(4)*, %opencl.clk_event_t{{.*}}* addrspace(4)*, i8*, i32, ...) @__enqueue_kernel_events_vaargs(%opencl_queue_t addrspace(1)* [[DEF_Q]], i32 [[FLAGS]], %struct.ndrange_t* {{.*}}, i32 2, %opencl.clk_event_t{{.*}} [[WAIT_EVNT]], %opencl.clk_event_t{{.*}} [[EVNT]], i8* bitcast ({ i8**, i32, i32, i8*, %struct.__block_descriptor addrspace(3)* }* @__block_literal_global{{(.[0-9]+)?}} to i8*), i32 1, i32 256)
   enqueue_kernel(default_queue, flags, ndrange, 2, event_wait_list2, &clk_event,
                  ^(local void *p) {
                    return;
@@ -76,8 +80,11 @@
   // CHECK: [[FLAGS:%[0-9]+]] = load i32, i32* %flags
   // CHECK: [[NDR:%[0-9]+]] = load %opencl.ndrange_t*, %opencl.ndrange_t** %ndrange
   // CHECK: [[AD:%arraydecay[0-9]*]] = getelementptr inbounds [1 x %opencl.clk_event_t*], [1 x %opencl.clk_event_t*]* %event_wait_list2, i32 0, i32 0
+  // CHECK: [[WAIT_EVNT:%[0-9]+]] = addrspacecast %opencl.clk_event_t addrspace(1)** [[AD]] to %opencl.clk_event_t addrspace(1)* addrspace(4)*
+  // CHECK: [[EVNT:%[0-9]+]]  = addrspacecast %opencl.clk_event_t addrspace(1)** %clk_event to %opencl.clk_event_t addrspace(1)* addrspace(4)*
+
   // CHECK: [[SIZE:%[0-9]+]] = zext i8 {{%[0-9]+}} to i32
-  // CHECK: call i32 (%opencl.queue_t*, i32, %opencl.ndrange_t*, i32, %opencl.clk_event_t**, %opencl.clk_event_t**, i8*, i32, ...) @__enqueue_kernel_events_vaargs(%opencl.queue_t* [[DEF_Q]], i32 [[FLAGS]], %opencl.ndrange_t* [[NDR]], i32 2, %opencl.clk_event_t** [[AD]], %opencl.clk_event_t** %clk_event, i8* bitcast ({ i8**, i32, i32, i8*, %struct.__block_descriptor addrspace(3)* }* @__block_literal_global{{(.[0-9]+)?}} to i8*), i32 1, i32 [[SIZE]])
+  // CHECK: call i32 (%opencl_queue_t addrspace(1)*, i32, %struct.ndrange_t*, i32, %opencl.clk_event_t{{.*}}* addrspace(4)*, %opencl.clk_event_t{{.*}}* addrspace(4)*, i8*, i32, ...) @__enqueue_kernel_events_vaargs(%opencl_queue_t addrspace(1)* [[DEF_Q]], i32 [[FLAGS]], %struct.ndrange_t* {{.*}}, i32 2, %opencl.clk_event_t{{.*}}* addrspace(4)* [[WAIT_EVNT]], %opencl.clk_event_t{{.*}}* addrspace(4)* [[EVNT]], i8* bitcast ({ i8**, i32, i32, i8*, %struct.__block_descriptor addrspace(3)* }* @__block_literal_global{{(.[0-9]+)?}} to i8*), i32 1, i32 [[SIZE]])
   enqueue_kernel(default_queue, flags, ndrange, 2, event_wait_list2, &clk_event,
                  ^(local void *p) {
                    return;
Index: test/SemaOpenCL/cl20-device-side-enqueue.cl
===================================================================
--- test/SemaOpenCL/cl20-device-side-enqueue.cl
+++ test/SemaOpenCL/cl20-device-side-enqueue.cl
@@ -36,8 +36,12 @@
 
   // Testing the second overload type
   enqueue_kernel(default_queue, flags, ndrange, 1, &event_wait_list, &evt, ^(void) {
-    return 0;
-  });
+                                                                             return 0;
+                                                                           });
+
+  enqueue_kernel(default_queue, flags, ndrange, 1, 0, 0, ^(void) {
+                                                           return 0;
+                                                         });
 
   enqueue_kernel(default_queue, flags, ndrange, 1, vptr, &evt, ^(void) // expected-error{{illegal call to enqueue_kernel, expected 'clk_event_t *' argument type}}
                                                                {
@@ -109,6 +113,12 @@
                  },
                  1024, 1024);
 
+  enqueue_kernel(default_queue, flags, ndrange, 1, 0, 0,
+                 ^(local void *a, local void *b) {
+                   return 0;
+                 },
+                 1024, 1024);
+
   enqueue_kernel(default_queue, flags, ndrange, 1, &event_wait_list, &evt, // expected-error{{mismatch in number of block parameters and local size arguments passed}}
                  ^(local void *a, local void *b) {
                    return 0;