Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/compiler-rt/test/tsan/libcxx/std_shared_ptr.cc

@@ -0,0 +1,24 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include <stdio.h>
+#include <memory>
+#include <thread>
+
+int main() {
+  int v1 = 0;
+  int v2 = 0;
+  std::thread t1;
+  std::thread t2;
+
+  {
+     auto thingy = std::make_shared<int>(42);
+     t1 = std::thread([thingy, &v1] { v1 = *thingy; });
+     t2 = std::thread([thingy, &v2] { v2 = *thingy; });
+  }
+
+  t1.join();
+  t2.join();
+  printf("%d %d\n", v1, v2);
+  // CHECK-NOT: ThreadSanitizer: data race
+  // CHECK: 42 42
+  return 0;
+}