diff --git a/libcxx/src/thread.cpp b/libcxx/src/thread.cpp
--- a/libcxx/src/thread.cpp
+++ b/libcxx/src/thread.cpp
@@ -115,8 +115,13 @@
 __thread_specific_ptr<__thread_struct>&
 __thread_local_data()
 {
-    static __thread_specific_ptr<__thread_struct> __p;
-    return __p;
+  // Even though __thread_specific_ptr's destructor doesn't actually destroy
+  // anything (see comments there), we can't call it at all because threads may
+  // outlive the static variable and calling its destructor means accessing an
+  // object outside of its lifetime, which is UB.
+  alignas(__thread_specific_ptr<__thread_struct>) static char __b[sizeof(__thread_specific_ptr<__thread_struct>)];
+  static __thread_specific_ptr<__thread_struct>* __p = new (__b) __thread_specific_ptr<__thread_struct>();
+  return *__p;
 }
 
 // __thread_struct_imp