Index: lib/Driver/Driver.cpp
===================================================================
--- lib/Driver/Driver.cpp
+++ lib/Driver/Driver.cpp
@@ -1200,7 +1200,10 @@
   // case-insensitive sorting for consistency with the -help option
   // which prints out options in the case-insensitive alphabetical order.
   std::sort(SuggestedCompletions.begin(), SuggestedCompletions.end(),
-            [](StringRef A, StringRef B) { return A.compare_lower(B) < 0; });
+            [](StringRef A, StringRef B) {
+              return A.equals_lower(B) ?
+                     A.compare(B) == 1 :
+                     A.compare_lower(B) < 0; });
 
   llvm::outs() << llvm::join(SuggestedCompletions, "\n") << '\n';
 }