[mc] Do not handle mc_model_checker->parent_snapshot unless it is necessary

diff --git a/src/mc/mc_checkpoint.c b/src/mc/mc_checkpoint.c
index 34b2281..f34cd60 100644 (file)
--- a/src/mc/mc_checkpoint.c
+++ b/src/mc/mc_checkpoint.c
@@ -569,7 +569,7 @@ int mc_important_snapshot(mc_snapshot_t snapshot)
 {
   // We need this snapshot in order to know which
   // pages needs to be stored in the next snapshot:
-  if (_sg_mc_sparse_checkpoint && snapshot == mc_model_checker->parent_snapshot)
+  if (snapshot == mc_model_checker->parent_snapshot)
     return true;
 
   return false;
@@ -608,7 +608,9 @@ mc_snapshot_t MC_take_snapshot(int num_state)
   }
 
   MC_snapshot_ignore_restore(snapshot);
-  mc_model_checker->parent_snapshot = snapshot;
+  if (_sg_mc_sparse_checkpoint && _sg_mc_soft_dirty) {
+    mc_model_checker->parent_snapshot = snapshot;
+  }
   return snapshot;
 }
 
@@ -639,7 +641,9 @@ void MC_restore_snapshot(mc_snapshot_t snapshot)
   }
 
   MC_snapshot_ignore_restore(snapshot);
-  mc_model_checker->parent_snapshot = snapshot;
+  if (_sg_mc_sparse_checkpoint && _sg_mc_soft_dirty) {
+    mc_model_checker->parent_snapshot = snapshot;
+  }
 }
 
 mc_snapshot_t SIMIX_pre_mc_snapshot(smx_simcall_t simcall)