Fix a build warning of unhandled enum in switch

Summary: LLVM adds a new value FMRB_DoesNotReadMemory in the enumeration.

Reviewers: andrew.w.kaylor, chrisj, zinob, grosser, jdoerfert

Subscribers: Meinersbur, pollydev

Differential Revision: http://reviews.llvm.org/D22109

llvm-svn: 275085
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 7d2dcbe..3770ae0 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -536,6 +536,8 @@
 
       Context.AST.add(&CI);
       return true;
+    case FMRB_DoesNotReadMemory:
+      return false;
     }
   }