Add '-p' option to 'constr' to allow fully removing constraints

Invoking 'constr -r' converts constraints into POs but does not fully
remove them. Now 'constr -pr' can be used to completely remove them,
leaving the set of non-constraint POs unchanged.

src/base/abci/abc.c

@@ -27974,17 +27974,20 @@ usage:
 int Abc_CommandConstr( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
     Abc_Ntk_t * pNtk;
+    Abc_Ntk_t * pNtkRes;
     int c;
     int nFrames;
     int nConfs;
     int nProps;
     int fRemove;
+    int fPurge;
     int fStruct;
     int fInvert;
     int fOldAlgo;
     int fVerbose;
     int nConstrs;
     extern void Abc_NtkDarConstr( Abc_Ntk_t * pNtk, int nFrames, int nConfs, int nProps, int fStruct, int fOldAlgo, int fVerbose );
+    extern Abc_Ntk_t * Abc_NtkMakeOnePo( Abc_Ntk_t * pNtk, int Output, int nRange );
 
     pNtk = Abc_FrameReadNtk(pAbc);
     // set defaults
@@ -27992,13 +27995,14 @@ int Abc_CommandConstr( Abc_Frame_t * pAbc, int argc, char ** argv )
     nConfs    =   1000;
     nProps    =   1000;
     fRemove   =      0;
+    fPurge    =      0;
     fStruct   =      0;
     fInvert   =      0;
     fOldAlgo  =      0;
     fVerbose  =      0;
     nConstrs  =     -1;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "FCPNrsiavh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "FCPNrpsiavh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -28049,6 +28053,9 @@ int Abc_CommandConstr( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 'r':
             fRemove ^= 1;
             break;
+        case 'p':
+            fPurge ^= 1;
+            break;
         case 's':
             fStruct ^= 1;
             break;
@@ -28084,7 +28091,22 @@ int Abc_CommandConstr( Abc_Frame_t * pAbc, int argc, char ** argv )
             Abc_Print( -1, "Constraints are not defined.\n" );
             return 0;
         }
-        Abc_Print( 1, "Constraints are converted to be primary outputs.\n" );
+
+        if ( fPurge )
+        {
+            Abc_Print( 1, "Constraints are removed.\n" );
+            pNtkRes = Abc_NtkMakeOnePo( pNtk, 0, Abc_NtkPoNum(pNtk) - Abc_NtkConstrNum(pNtk) );
+            if ( pNtkRes == NULL )
+            {
+                Abc_Print( 1,"Transformation has failed.\n" );
+                return 1;
+            }
+            // replace the current network
+            Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
+            pNtk = Abc_FrameReadNtk(pAbc);
+        }
+        else
+            Abc_Print( 1, "Constraints are converted to be primary outputs.\n" );
         pNtk->nConstrs = 0;
         return 0;
     }
@@ -28129,7 +28151,7 @@ int Abc_CommandConstr( Abc_Frame_t * pAbc, int argc, char ** argv )
     Abc_NtkDarConstr( pNtk, nFrames, nConfs, nProps, fStruct, fOldAlgo, fVerbose );
     return 0;
 usage:
-    Abc_Print( -2, "usage: constr [-FCPN num] [-risavh]\n" );
+    Abc_Print( -2, "usage: constr [-FCPN num] [-rpisavh]\n" );
     Abc_Print( -2, "\t         a toolkit for constraint manipulation\n" );
     Abc_Print( -2, "\t         if constraints are absent, detect them functionally\n" );
     Abc_Print( -2, "\t         if constraints are present, profiles them using random simulation\n" );
@@ -28138,7 +28160,8 @@ usage:
     Abc_Print( -2, "\t-C num : the max number of conflicts in SAT solving [default = %d]\n", nConfs );
     Abc_Print( -2, "\t-P num : the max number of propagations in SAT solving [default = %d]\n", nProps );
     Abc_Print( -2, "\t-N num : manually set the last <num> POs to be constraints [default = %d]\n", nConstrs );
-    Abc_Print( -2, "\t-r     : manually remove the constraints [default = %s]\n", fRemove? "yes": "no" );
+    Abc_Print( -2, "\t-r     : manually remove the constraints, converting them to POs [default = %s]\n", fRemove? "yes": "no" );
+    Abc_Print( -2, "\t-p     : remove constraints instead of converting them to POs [default = %s]\n", fPurge? "yes": "no" );
     Abc_Print( -2, "\t-i     : toggle inverting already defined constraints [default = %s]\n", fInvert? "yes": "no" );
     Abc_Print( -2, "\t-s     : toggle using structural detection methods [default = %s]\n", fStruct? "yes": "no" );
     Abc_Print( -2, "\t-a     : toggle fast implication detection [default = %s]\n", !fOldAlgo? "yes": "no" );