Index: cfe/trunk/lib/Sema/SemaChecking.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp
+++ cfe/trunk/lib/Sema/SemaChecking.cpp
@@ -2868,6 +2868,9 @@
           Ty = Context.getPointerDiffType();
         else {
           Expr *ValArg = TheCall->getArg(i);
+          // Treat this argument as _Nonnull as we want to show a warning if
+          // NULL is passed into it.
+          CheckNonNullArgument(*this, ValArg, DRE->getLocStart());
           unsigned AS = 0;
           // Keep address space of non-atomic pointer type.
           if (const PointerType *PtrTy =
Index: cfe/trunk/test/Sema/atomic-ops.c
===================================================================
--- cfe/trunk/test/Sema/atomic-ops.c
+++ cfe/trunk/test/Sema/atomic-ops.c
@@ -174,14 +174,14 @@
   __atomic_fetch_or(D, 3, memory_order_seq_cst); // expected-error {{must be a pointer to integer}}
   __atomic_fetch_and(s1, 3, memory_order_seq_cst); // expected-error {{must be a pointer to integer}}
 
-  _Bool cmpexch_1 = __c11_atomic_compare_exchange_strong(i, 0, 1, memory_order_seq_cst, memory_order_seq_cst);
-  _Bool cmpexch_2 = __c11_atomic_compare_exchange_strong(p, 0, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
-  _Bool cmpexch_3 = __c11_atomic_compare_exchange_strong(d, (int*)0, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
+  _Bool cmpexch_1 = __c11_atomic_compare_exchange_strong(i, I, 1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexch_2 = __c11_atomic_compare_exchange_strong(p, P, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexch_3 = __c11_atomic_compare_exchange_strong(d, I, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
   (void)__c11_atomic_compare_exchange_strong(i, CI, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
-  _Bool cmpexchw_1 = __c11_atomic_compare_exchange_weak(i, 0, 1, memory_order_seq_cst, memory_order_seq_cst);
-  _Bool cmpexchw_2 = __c11_atomic_compare_exchange_weak(p, 0, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
-  _Bool cmpexchw_3 = __c11_atomic_compare_exchange_weak(d, (int*)0, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
+  _Bool cmpexchw_1 = __c11_atomic_compare_exchange_weak(i, I, 1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexchw_2 = __c11_atomic_compare_exchange_weak(p, P, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexchw_3 = __c11_atomic_compare_exchange_weak(d, I, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
   (void)__c11_atomic_compare_exchange_weak(i, CI, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
   _Bool cmpexch_4 = __atomic_compare_exchange_n(I, I, 5, 1, memory_order_seq_cst, memory_order_seq_cst);
@@ -503,4 +503,9 @@
   (void)__atomic_compare_exchange_n(p, p, val, 0, memory_order_seq_cst, memory_order_relaxed);
 }
 
-
+void nullPointerWarning(_Atomic(int) *Ap, int *p, int val) {
+  // The 'expected' pointer shouldn't be NULL.
+  (void)__c11_atomic_compare_exchange_strong(Ap, NULL, val, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+  (void)atomic_compare_exchange_weak(Ap, ((void*)0), val); // expected-warning {{null passed to a callee that requires a non-null argument}}
+  (void)__atomic_compare_exchange_n(p, NULL, val, 0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+}