diff --git a/include/llvm/Support/ManagedStatic.h b/include/llvm/Support/ManagedStatic.h
index 7eecce3..619cc20 100644
--- a/include/llvm/Support/ManagedStatic.h
+++ b/include/llvm/Support/ManagedStatic.h
@@ -96,8 +96,10 @@
 
 
 /// llvm_start_multithreaded - Allocate and initialize structures needed to
-/// make LLVM safe for multithreading.
-void llvm_start_multithreaded();
+/// make LLVM safe for multithreading.  The return value indicates whether
+/// multithreaded initialization succeeded.  LLVM will still be operational
+/// on "failed" return, but will not be safe to run multithreaded.
+bool llvm_start_multithreaded();
 
 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
 void llvm_shutdown();
diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp
index 056b6c0..a3b2bcc 100644
--- a/lib/Support/ManagedStatic.cpp
+++ b/lib/Support/ManagedStatic.cpp
@@ -68,12 +68,13 @@
   DeleterFn = 0;
 }
 
-void llvm::llvm_start_multithreaded() {
+bool llvm::llvm_start_multithreaded() {
 #if LLVM_MULTITHREADED
   assert(ManagedStaticMutex == 0 && "Multithreaded LLVM already initialized!");
   ManagedStaticMutex = new sys::Mutex(true);
+  return true;
 #else
-  assert(0 && "LLVM built without multithreading support!");
+  return false;
 #endif
 }