1 files changed, 37 insertions, 0 deletions
diff --git a/test/tsan/libdispatch/async-race.c b/test/tsan/libdispatch/async-race.c
new file mode 100644
index 000000000..6701f101c
--- /dev/null
+++ b/test/tsan/libdispatch/async-race.c
@@ -0,0 +1,37 @@
+// RUN: %clang_tsan %s -o %t
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
+
+#include "dispatch/dispatch.h"
+
+#include "../test.h"
+
+long global;
+
+int main() {
+  fprintf(stderr, "Hello world.\n");
+  print_address("addr=", 1, &global);
+  dispatch_semaphore_t done = dispatch_semaphore_create(0);
+  barrier_init(&barrier, 2);
+
+  global = 42;
+  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+    global = 43;
+    barrier_wait(&barrier);
+  });
+
+  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+    barrier_wait(&barrier);
+    global = 44;
+
+    dispatch_semaphore_signal(done);
+  });
+
+  dispatch_semaphore_wait(done, DISPATCH_TIME_FOREVER);
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: addr=[[ADDR:0x[0-9,a-f]+]]
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK: Location is global 'global' {{(of size 8 )?}}at [[ADDR]] (async-race.c.tmp+0x{{[0-9,a-f]+}})
+// CHECK: Done.