diff --git a/lib/CompilerDriver/CompilationGraph.cpp b/lib/CompilerDriver/CompilationGraph.cpp
index d0c0e15..0aecfa6 100644
--- a/lib/CompilerDriver/CompilationGraph.cpp
+++ b/lib/CompilerDriver/CompilationGraph.cpp
@@ -218,10 +218,11 @@
               InputLanguagesSet& InLangs, const LanguageMap& LangMap) const {
 
   // Determine the input language.
-  const std::string* InLang = LangMap.GetLanguage(In);
+  const std::string* InLang = (ForceLanguage ? ForceLanguage
+                               : LangMap.GetLanguage(In));
   if (InLang == 0)
     return 0;
-  const std::string& InLanguage = (ForceLanguage ? *ForceLanguage : *InLang);
+  const std::string& InLanguage = *InLang;
 
   // Add the current input language to the input language set.
   InLangs.insert(InLanguage);