Print "null" for ISL objects that are nullptr

Use it to print "null" if a MemoryAccess's access relation is not
available instead of printing nothing.

Suggested-by: Johannes Doerfert
llvm-svn: 255466
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 9d7a433..86a2023 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -747,8 +747,7 @@
   }
   OS << "[Reduction Type: " << getReductionType() << "] ";
   OS << "[Scalar: " << isImplicit() << "]\n";
-  if (AccessRelation)
-    OS.indent(16) << getOriginalAccessRelationStr() << ";\n";
+  OS.indent(16) << getOriginalAccessRelationStr() << ";\n";
   if (hasNewAccessRelation())
     OS.indent(11) << "new: " << getNewAccessRelationStr() << ";\n";
 }