Further fix: avoid back-edges in traversing region

hpvm/projects/hetero-c++/lib/HCCVerifier.cpp

@@ -728,9 +728,14 @@ bool HCCVerifier::verifyUses(RegionTree& region, std::set<Value*> inputs,
                 extraInstructions = true;
               } else {
                 // Add the basic blocks we can reach from this branch to the
-                // list to explore (if we haven't already)
+                // list to explore (if we haven't already). We also don't add
+                // back-edges since they should already have been processed
+                // (and if not, only because we skipped over the body because
+                // it was a parallel loop)
                 for (BasicBlock* succ : branch->successors()) {
-                  if (reached.find(succ) == reached.end()) {
+                  if (reached.find(succ) == reached.end()
+                    && (succ != branch->getParent() 
+                       && !DTCache.dominates(succ, branch->getParent()))) {
                     toSearch.insert(succ);
                   }
                 }