scop detection: check flag before expensive call

llvm-svn: 184000
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 6642e69..8ae485c 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -266,8 +266,8 @@
 
   AccessFunction = SE->getMinusSCEV(AccessFunction, BasePointer);
 
-  if (!isAffineExpr(&Context.CurRegion, AccessFunction, *SE, BaseValue) &&
-      !AllowNonAffine)
+  if (!AllowNonAffine && !isAffineExpr(&Context.CurRegion, AccessFunction, *SE,
+                                       BaseValue))
     INVALID(AffFunc, "Non affine access function: " << *AccessFunction);
 
   // FIXME: Alias Analysis thinks IntToPtrInst aliases with alloca instructions