Fixing assertion failure when all POs have constant functions.

src/map/scl/sclSize.c

@@ -50,12 +50,15 @@ Abc_Obj_t * Abc_SclFindCriticalCo( SC_Man * p, int * pfRise )
     Abc_Obj_t * pObj, * pPivot = NULL;
     float fMaxArr = 0;
     int i;
+    assert( Abc_NtkPoNum(p->pNtk) > 0 );
     Abc_NtkForEachCo( p->pNtk, pObj, i )
     {
         SC_Pair * pArr = Abc_SclObjTime( p, pObj );
         if ( fMaxArr < pArr->rise )  fMaxArr = pArr->rise, *pfRise = 1, pPivot = pObj;
         if ( fMaxArr < pArr->fall )  fMaxArr = pArr->fall, *pfRise = 0, pPivot = pObj;
     }
+    if ( fMaxArr == 0 )
+        pPivot = Abc_NtkPo(p->pNtk, 0);
     assert( pPivot != NULL );
     return pPivot;
 }

src/map/scl/sclUpsize.c

@@ -898,7 +898,7 @@ void Abc_SclUpsizePerform( SC_Lib * pLib, Abc_Ntk_t * pNtk, SC_SizePars * pPars
     // perform upsizing
     nAllPos = nAllNodes = nAllTfos = nAllUpsizes = 0;
     if ( p->BestDelay <= pPars->DelayUser )
-        printf( "Current delay (%.2f ps) is better than the target delay (%.2f ps).\n", p->BestDelay, (float)pPars->DelayUser );
+        printf( "Current delay (%.2f ps) does not exceed the target delay (%.2f ps). Upsizing is not performed.\n", p->BestDelay, (float)pPars->DelayUser );
     else
     for ( i = 0; i < pPars->nIters; i++ )
     {