Adding switch to control the number of nodes tried in mfs2.

src/base/abci/abc.c

@@ -4587,7 +4587,7 @@ int Abc_CommandMfs2( Abc_Frame_t * pAbc, int argc, char ** argv )
     // set defaults
     Sfm_ParSetDefault( pPars );
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "WFDMLCZdaevwh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "WFDMLCZNdaevwh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -4668,6 +4668,17 @@ int Abc_CommandMfs2( Abc_Frame_t * pAbc, int argc, char ** argv )
             if ( pPars->nFirstFixed < 0 )
                 goto usage;
             break;
+        case 'N':
+            if ( globalUtilOptind >= argc )
+            {
+                Abc_Print( -1, "Command line switch \"-N\" should be followed by an integer.\n" );
+                goto usage;
+            }
+            pPars->nNodesMax = atoi(argv[globalUtilOptind]);
+            globalUtilOptind++;
+            if ( pPars->nNodesMax < 0 )
+                goto usage;
+            break;
         case 'd':
             pPars->fRrOnly ^= 1;
             break;
@@ -4708,7 +4719,7 @@ int Abc_CommandMfs2( Abc_Frame_t * pAbc, int argc, char ** argv )
     return 0;
 
 usage:
-    Abc_Print( -2, "usage: mfs2 [-WFDMLCZ <num>] [-daevwh]\n" );
+    Abc_Print( -2, "usage: mfs2 [-WFDMLCZN <num>] [-daevwh]\n" );
     Abc_Print( -2, "\t           performs don't-care-based optimization of logic networks\n" );
     Abc_Print( -2, "\t-W <num> : the number of levels in the TFO cone (0 <= num) [default = %d]\n",             pPars->nTfoLevMax );
     Abc_Print( -2, "\t-F <num> : the max number of fanouts to skip (1 <= num) [default = %d]\n",                pPars->nFanoutMax );
@@ -4717,6 +4728,7 @@ usage:
     Abc_Print( -2, "\t-L <num> : the max increase in node level after resynthesis (0 <= num) [default = %d]\n", pPars->nGrowthLevel );
     Abc_Print( -2, "\t-C <num> : the max number of conflicts in one SAT run (0 = no limit) [default = %d]\n",   pPars->nBTLimit );
     Abc_Print( -2, "\t-Z <num> : treat the first <num> logic nodes as fixed (0 = none) [default = %d]\n",       pPars->nFirstFixed );
+    Abc_Print( -2, "\t-N <num> : the max number of nodes to try (0 = all) [default = %d]\n",                    pPars->nNodesMax );
     Abc_Print( -2, "\t-d       : toggle performing redundancy removal [default = %s]\n",                        pPars->fRrOnly? "yes": "no" );
     Abc_Print( -2, "\t-a       : toggle minimizing area or area+edges [default = %s]\n",                        pPars->fArea? "area": "area+edges" );
     Abc_Print( -2, "\t-e       : toggle high-effort resubstitution [default = %s]\n",                           pPars->fMoreEffort? "yes": "no" );

src/opt/sfm/sfm.h

@@ -48,6 +48,7 @@ struct Sfm_Par_t_
     int             nWinSizeMax;   // the maximum window size
     int             nGrowthLevel;  // the maximum allowed growth in level
     int             nBTLimit;      // the maximum number of conflicts in one SAT run
+    int             nNodesMax;     // the maximum number of nodes to try
     int             nFirstFixed;   // the number of first nodes to be treated as fixed
     int             fRrOnly;       // perform redundance removal
     int             fArea;         // performs optimization for area

src/opt/sfm/sfmCore.c

@@ -280,6 +280,8 @@ int Sfm_NtkPerform( Sfm_Ntk_t * p, Sfm_Par_t * pPars )
 //            break;
         }
         Counter += (k > 0);
+        if ( pPars->nNodesMax && Counter >= pPars->nNodesMax )
+            break;
     }
     p->nTotalNodesEnd = Vec_WecSizeUsedLimits( &p->vFanins, Sfm_NtkPiNum(p), Vec_WecSize(&p->vFanins) - Sfm_NtkPoNum(p) );
     p->nTotalEdgesEnd = Vec_WecSizeSize(&p->vFanins) - Sfm_NtkPoNum(p);

src/opt/sfm/sfmNtk.c

@@ -213,7 +213,7 @@ void Sfm_NtkFree( Sfm_Ntk_t * p )
 {
     // user data
     Vec_StrFree( p->vFixed );
-    Vec_StrFree( p->vEmpty );
+    Vec_StrFreeP( &p->vEmpty );
     Vec_WrdFree( p->vTruths );
     Vec_WecErase( &p->vFanins );
     // attributes