Index: lib/Support/CommandLine.cpp
===================================================================
--- lib/Support/CommandLine.cpp
+++ lib/Support/CommandLine.cpp
@@ -103,7 +103,8 @@
   // This collects the different option categories that have been registered.
   SmallPtrSet<OptionCategory *, 16> RegisteredOptionCategories;
 
-  CommandLineParser() : ProgramOverview(nullptr), ConsumeAfterOpt(nullptr) {}
+  CommandLineParser()
+      : ProgramOverview(nullptr), OptionsMap(512), ConsumeAfterOpt(nullptr) {}
 
   void ParseCommandLineOptions(int argc, const char *const *argv,
                                const char *Overview);