Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

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

@@ -0,0 +1,22 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
+#include "test.h"
+
+void *Thread(void *a) {
+  barrier_wait(&barrier);
+  *(int*)a = 43;
+  return 0;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  int Var = 42;
+  pthread_t t;
+  pthread_create(&t, 0, Thread, &Var);
+  Var = 43;
+  barrier_wait(&barrier);
+  pthread_join(t, 0);
+}
+
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK:   Location is stack of main thread.
+