--- src/aig/gia/gia.h.orig	2023-07-14 10:53:06.361679474 -0600
+++ src/aig/gia/gia.h	2023-07-14 10:54:12.069684316 -0600
@@ -1142,7 +1142,7 @@ 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_LutForEachFaninIndex( p, i, iFan, k, Index )                            \
     for ( k = 0; k < Gia_ObjLutSize(p,i) && (Index = Vec_IntEntry(p->vMapping, i)+1+k) && ((iFan = Vec_IntEntry(p->vMapping, Index)),1); k++ )
 #define Gia_LutForEachFaninObj( p, i, pFanin, k )                       \