Allow to annotate alias scopes in the new SCoP.

  The command line flag -polly-annotate-alias-scopes controls whether or not
  Polly annotates alias scopes in the new SCoP (default ON). This can improve
  later optimizations as the new SCoP is basically an alias free environment for
  them.

llvm-svn: 218877
diff --git a/polly/lib/CodeGen/IslCodeGeneration.cpp b/polly/lib/CodeGen/IslCodeGeneration.cpp
index f5599ee..68ed943 100644
--- a/polly/lib/CodeGen/IslCodeGeneration.cpp
+++ b/polly/lib/CodeGen/IslCodeGeneration.cpp
@@ -605,6 +605,10 @@
     assert(!S.getRegion().isTopLevelRegion() &&
            "Top level regions are not supported");
 
+    // Build the alias scopes for annotations first.
+    if (PollyAnnotateAliasScopes)
+      Annotator.buildAliasScopes(S);
+
     BasicBlock *EnteringBB = simplifyRegion(&S, this);
     PollyIRBuilder Builder = createPollyIRBuilder(EnteringBB, Annotator);