diff --git a/llvm/lib/Support/ManagedStatic.cpp b/llvm/lib/Support/ManagedStatic.cpp
--- a/llvm/lib/Support/ManagedStatic.cpp
+++ b/llvm/lib/Support/ManagedStatic.cpp
@@ -27,6 +27,13 @@
 
 static std::recursive_mutex *getManagedStaticMutex() {
   llvm::call_once(mutex_init_flag, initializeMutex);
+  // corner case handling - for tests purposes
+  // [this 'if' will not be triggered in real world app]
+  // it is for covering test case where RegisterManagedStatic
+  // is called AFTER llvm_shutdown
+  if (ManagedStaticMutex == nullptr) {
+    initializeMutex();
+  }
   return ManagedStaticMutex;
 }
 
@@ -76,8 +83,12 @@
 
 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
 void llvm::llvm_shutdown() {
-  std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
+  {
+    std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
 
-  while (StaticList)
-    StaticList->destroy();
+    while (StaticList)
+      StaticList->destroy();
+  }
+  delete ManagedStaticMutex;
+  ManagedStaticMutex = nullptr;
 }