diff --git a/llvm/lib/Option/OptTable.cpp b/llvm/lib/Option/OptTable.cpp
--- a/llvm/lib/Option/OptTable.cpp
+++ b/llvm/lib/Option/OptTable.cpp
@@ -198,8 +198,8 @@
 static bool optionMatches(const OptTable::Info &In, StringRef Option) {
   if (In.Prefixes)
     for (size_t I = 0; In.Prefixes[I]; I++)
-      if (Option.endswith(In.Name))
-        if (Option == std::string(In.Prefixes[I]) + In.Name)
+      if (Option.consume_back(In.Name))
+        if (Option.equals(In.Prefixes[I]))
           return true;
   return false;
 }