diff --git a/lib/Analysis/ScopDetection.cpp b/lib/Analysis/ScopDetection.cpp
index 4dfcf34..045d0f9 100644
--- a/lib/Analysis/ScopDetection.cpp
+++ b/lib/Analysis/ScopDetection.cpp
@@ -329,7 +329,8 @@
 
     std::string Err;
     if (!R.isValid(Err))
-      report_fatal_error("invalid regex given as input to polly: " + Err, true);
+      report_fatal_error(Twine("invalid regex given as input to polly: ") + Err,
+                         true);
 
     if (R.match(Str))
       return true;