diff --git a/module.cpp b/module.cpp
index e05f83e6..9e4defb8 100644
--- a/module.cpp
+++ b/module.cpp
@@ -1897,7 +1897,11 @@ Module::execPreprocessor(const char *infilename, llvm::raw_string_ostream *ostre
         }
     }
 
+#if defined(LLVM_3_1)
+    inst.getLangOpts().BCPLComment = 1;
+#else
     inst.getLangOpts().LineComment = 1;
+#endif
     inst.createPreprocessor();
 
     diagPrinter->BeginSourceFile(inst.getLangOpts(), &inst.getPreprocessor());