Index: docs/LinkTimeOptimization.rst
===================================================================
--- docs/LinkTimeOptimization.rst
+++ docs/LinkTimeOptimization.rst
@@ -87,9 +87,9 @@
 
 .. code-block:: console
 
-  % clang -emit-llvm -c a.c -o a.o   # <-- a.o is LLVM bitcode file
+  % clang -flto -c a.c -o a.o        # <-- a.o is LLVM bitcode file
   % clang -c main.c -o main.o        # <-- main.o is native object file
-  % clang a.o main.o -o main         # <-- standard link command without modifications
+  % clang -flto a.o main.o -o main   # <-- standard link command without modifications
 
 * In this example, the linker recognizes that ``foo2()`` is an externally
   visible symbol defined in LLVM bitcode file. The linker completes its usual
Index: lib/Transforms/IPO/FunctionImport.cpp
===================================================================
--- lib/Transforms/IPO/FunctionImport.cpp
+++ lib/Transforms/IPO/FunctionImport.cpp
@@ -591,12 +591,14 @@
                    << SrcModule->getSourceFileName() << "\n");
       if (Import) {
         F.materialize();
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
         // Add 'thinlto_src_module' metadata for statistics and debugging.
         F.setMetadata("thinlto_src_module",
                       llvm::MDNode::get(DestModule.getContext(),
                                         {llvm::MDString::get(
                                             DestModule.getContext(),
                                             SrcModule->getSourceFileName())}));
+#endif  // !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
         GlobalsToImport.insert(&F);
       }
     }