diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -744,7 +744,7 @@
                           ArrayRef<std::string> Dirs,
                           StringRef FileName) {
   SmallString<128> WPath;
-  for (const StringRef &Dir : Dirs) {
+  for (const std::string &Dir : Dirs) {
     if (Dir.empty())
       continue;
     WPath.clear();
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -850,7 +850,7 @@
 /*static*/ void ToolChain::addSystemIncludes(const ArgList &DriverArgs,
                                              ArgStringList &CC1Args,
                                              ArrayRef<StringRef> Paths) {
-  for (const auto Path : Paths) {
+  for (const auto &Path : Paths) {
     CC1Args.push_back("-internal-isystem");
     CC1Args.push_back(DriverArgs.MakeArgString(Path));
   }