1 files changed, 37 insertions, 0 deletions
diff --git a/test/tsan/libdispatch/sync-norace.c b/test/tsan/libdispatch/sync-norace.c
new file mode 100644
index 000000000..38d9be384
--- /dev/null
+++ b/test/tsan/libdispatch/sync-norace.c
@@ -0,0 +1,37 @@
+// RUN: %clang_tsan %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s
+
+#include "dispatch/dispatch.h"
+
+#include <stdio.h>
+
+long global;
+
+static const long nIter = 1000;
+
+int main() {
+  fprintf(stderr, "Hello world.\n");
+  dispatch_semaphore_t done = dispatch_semaphore_create(0);
+
+  dispatch_queue_t serial_q = dispatch_queue_create("my.queue", DISPATCH_QUEUE_SERIAL);
+
+  global = 42;
+  for (int i = 0; i < nIter; i++) {
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+      dispatch_sync(serial_q, ^{
+        global = i;
+
+        if (i == nIter - 1) {
+          dispatch_semaphore_signal(done);
+        }
+      });
+    });
+  }
+
+  dispatch_semaphore_wait(done, DISPATCH_TIME_FOREVER);
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: Done.
+// CHECK-NOT: WARNING: ThreadSanitizer