diff --git a/llvm/cmake/modules/CheckAtomic.cmake b/llvm/cmake/modules/CheckAtomic.cmake
--- a/llvm/cmake/modules/CheckAtomic.cmake
+++ b/llvm/cmake/modules/CheckAtomic.cmake
@@ -12,8 +12,12 @@
   CHECK_CXX_SOURCE_COMPILES("
 #include <atomic>
 std::atomic<int> x;
+std::atomic<short> y;
+std::atomic<char> z;
 int main() {
-  return x;
+  ++z;
+  ++y;
+  return ++x;
 }
 " ${varname})
   set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})