test for something more interesting than not crashing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47962 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CFrontend/2008-03-05-syncPtr.c b/test/CFrontend/2008-03-05-syncPtr.c
index ddd7d5b..6d5be5d 100644
--- a/test/CFrontend/2008-03-05-syncPtr.c
+++ b/test/CFrontend/2008-03-05-syncPtr.c
@@ -1,4 +1,4 @@
-// RUN: %llvmgcc %s -S -emit-llvm -o /dev/null 
+// RUN: %llvmgcc %s -S -emit-llvm -o - | grep llvm.atomic
 
 int* foo(int** a, int* b, int* c) {
 return __sync_val_compare_and_swap (a, b, c);