1 files changed, 30 insertions, 0 deletions
diff --git a/test/tsan/libdispatch/apply-race.c b/test/tsan/libdispatch/apply-race.c
new file mode 100644
index 000000000..10e954c23
--- /dev/null
+++ b/test/tsan/libdispatch/apply-race.c
@@ -0,0 +1,30 @@
+// 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(int argc, const char *argv[]) {
+  barrier_init(&barrier, 2);
+  fprintf(stderr, "start\n");
+
+  // Warm up GCD (workaround for macOS Sierra where dispatch_apply might run single-threaded).
+  dispatch_sync(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ });
+
+  dispatch_queue_t q = dispatch_queue_create("my.queue", DISPATCH_QUEUE_CONCURRENT);
+  dispatch_apply(2, q, ^(size_t i) {
+    global = i;
+    barrier_wait(&barrier);
+  });
+
+  fprintf(stderr, "done\n");
+  return 0;
+}
+
+// CHECK: start
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK: Location is global 'global'
+// CHECK: done