fix mistake in promises may allow code... need to be even more aggressive about fv

diff --git a/model.cc b/model.cc
index 167ea947a79a020964ec13fc67d67077aae961f7..7df70eebbe271c88486a4c85e4289217f1a40e4b 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -1056,7 +1056,7 @@ bool ModelChecker::process_mutex(ModelAction *curr)
  *
  * If one of the following is true:
  *  (a) there are no pending promises
- *  (b) the reader is ordered after the latest Promise creation
+ *  (b) the reader and writer do not cross any promises
  * Then, it is safe to pass a future value back now.
  *
  * Otherwise, we must save the pending future value until (a) or (b) is true
@@ -1068,8 +1068,18 @@ bool ModelChecker::process_mutex(ModelAction *curr)
 bool ModelChecker::promises_may_allow(const ModelAction *writer,
                const ModelAction *reader) const
 {
-       return promises->empty() ||
-               *(promises->back()->get_reader(0)) < *reader;
+       if (promises->empty())
+               return true;
+       for(int i=promises->size()-1;i>=0;i--) {
+               ModelAction *pr=(*promises)[i]->get_reader(0);
+               //reader is after promise...doesn't cross any promise
+               if (*reader > *pr)
+                       return true;
+               //writer is after promise, reader before...bad...
+               if (*writer > *pr)
+                       return false;
+       }
+       return true;
 }
 
 /**