1 files changed, 6 insertions, 3 deletions
diff --git a/src/sat/cnf/cnfMan.c b/src/sat/cnf/cnfMan.c
index 8a155f78..a2d74b1c 100644
--- a/src/sat/cnf/cnfMan.c
+++ b/src/sat/cnf/cnfMan.c
@@ -206,9 +206,12 @@ void Cnf_DataLift( Cnf_Dat_t * p, int nVarsPlus )
 {
     Aig_Obj_t * pObj;
     int v;
-    Aig_ManForEachObj( p->pMan, pObj, v )
-        if ( p->pVarNums[pObj->Id] >= 0 )
-            p->pVarNums[pObj->Id] += nVarsPlus;
+    if ( p->pMan )
+    {
+        Aig_ManForEachObj( p->pMan, pObj, v )
+            if ( p->pVarNums[pObj->Id] >= 0 )
+                p->pVarNums[pObj->Id] += nVarsPlus;
+    }
     for ( v = 0; v < p->nLiterals; v++ )
         p->pClauses[0][v] += 2*nVarsPlus;
 }