--- src/aig/gia/gia.h.orig 2020-07-20 20:56:06.000000000 -0600
+++ src/aig/gia/gia.h 2020-07-24 15:13:12.699364636 -0600
@@ -1118,7 +1118,7 @@ static inline int Gia_ObjCellId(
#define Gia_ManForEachLutReverse( p, i ) \
for ( i = Gia_ManObjNum(p) - 1; i > 0; i-- ) if ( !Gia_ObjIsLut(p, i) ) {} else
#define Gia_LutForEachFanin( p, i, iFan, k ) \
- for ( k = 0; k < Gia_ObjLutSize(p,i) && ((iFan = Gia_ObjLutFanins(p,i)[k]),1); k++ )
+ for ( k = 0; k < Gia_ObjLutSize(p,i) && ((iFan = Gia_ObjLutFanins(p,i)[k]),1); k++ ) if (iFan >= 0)
#define Gia_LutForEachFaninObj( p, i, pFanin, k ) \
for ( k = 0; k < Gia_ObjLutSize(p,i) && ((pFanin = Gia_ManObj(p, Gia_ObjLutFanins(p,i)[k])),1); k++ )