Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

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

@@ -0,0 +1,30 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
+#include <pthread.h>
+#include <stdio.h>
+
+extern "C" void AnnotateIgnoreSyncBegin(const char*, int);
+extern "C" void AnnotateIgnoreSyncEnd(const char*, int);
+
+int Global;
+pthread_mutex_t Mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void *Thread(void *x) {
+  AnnotateIgnoreSyncBegin(0, 0);
+  pthread_mutex_lock(&Mutex);
+  Global++;
+  pthread_mutex_unlock(&Mutex);
+  AnnotateIgnoreSyncEnd(0, 0);
+  return 0;
+}
+
+int main() {
+  pthread_t t;
+  pthread_create(&t, 0, Thread, 0);
+  pthread_mutex_lock(&Mutex);
+  Global++;
+  pthread_mutex_unlock(&Mutex);
+  pthread_join(t, 0);
+}
+
+// CHECK: WARNING: ThreadSanitizer: data race
+