right fix for avoid rmw cycles... bad assumption in the cyclegraph

[model-checker.git] / cyclegraph.cc

diff --git a/cyclegraph.cc b/cyclegraph.cc
index 2bac4de7cf0469c57818ceab835458a872bb7c29..62330624d6f08a233292ddfee1269380e8869beb 100644 (file)
--- a/cyclegraph.cc
+++ b/cyclegraph.cc
@@ -85,8 +85,12 @@ void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw) {
        }
 
        /* Transfer all outgoing edges from the from node to the rmw node */
-       /* This process cannot add a cycle because rmw should not have any
-                incoming edges yet.*/
+       /* This process should not add a cycle because either: 
+        * (1) The rmw should not have any incoming edges yet if it is the
+        * new node or
+        * (2) the fromnode is the new node and therefore it should not 
+        * have any outgoing edges.
+        */
        std::vector<CycleNode *> * edges=fromnode->getEdges();
        for(unsigned int i=0;i<edges->size();i++) {
                CycleNode * tonode=(*edges)[i];
@@ -94,6 +98,12 @@ void CycleGraph::addRMWEdge(const ModelAction *from, const ModelAction *rmw) {
                rmwnode->addEdge(tonode);
        }
        rollbackvector.push_back(fromnode);
+
+       if (!hasCycles) {
+               // With promises we could be setting up a cycle here if we aren't
+               // careful...avoid it..
+               hasCycles=checkReachable(rmwnode, fromnode);
+       }
        fromnode->addEdge(rmwnode);
 }