Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/compiler-rt/test/tsan/race_stress.cc

@@ -0,0 +1,25 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
+#include "test.h"
+
+const int kThreads = 16;
+const int kIters = 1000;
+
+volatile int X = 0;
+
+void *thr(void *arg) {
+  for (int i = 0; i < kIters; i++)
+    X++;
+  return 0;
+}
+
+int main() {
+  pthread_t th[kThreads];
+  for (int i = 0; i < kThreads; i++)
+    pthread_create(&th[i], 0, thr, 0);
+  for (int i = 0; i < kThreads; i++)
+    pthread_join(th[i], 0);
+  fprintf(stderr, "DONE\n");
+}
+
+// CHECK: ThreadSanitizer: data race
+// CHECK: DONE