Merge pull request #559 from calewis/fast_reverse_level

Avoid pointer chasing for pFanout->Id when we already have it in `Aig_ManUpdateReverseLevel`

Author: alanminko

src/aig/aig/aig.h

@@ -428,6 +428,10 @@ static inline int     Aig_ObjFanoutNext( Aig_Man_t * p, int iFan )   { assert(iF
     for ( assert(p->pFanData), i = 0; (i < (int)(pObj)->nRefs) &&               \
           (((iFan) = i? Aig_ObjFanoutNext(p, iFan) : Aig_ObjFanout0Int(p, pObj->Id)), 1) && \
           (((pFanout) = Aig_ManObj(p, iFan>>1)), 1); i++ )
+#define Aig_ObjForEachFanoutId( p, pObj, FanId, iFan, i )                       \
+    for ( assert(p->pFanData), i = 0; (i < (int)(pObj)->nRefs) &&               \
+          (((iFan) = i? Aig_ObjFanoutNext(p, iFan) : Aig_ObjFanout0Int(p, pObj->Id)), 1) && \
+          (((FanId) = (iFan >> 1)), 1); i++ )
 
 
 ////////////////////////////////////////////////////////////////////////

src/aig/aig/aigTiming.c

@@ -116,11 +116,10 @@ int Aig_ObjRequiredLevel( Aig_Man_t * p, Aig_Obj_t * pObj )
 ***********************************************************************/
 int Aig_ObjReverseLevelNew( Aig_Man_t * p, Aig_Obj_t * pObj )
 {
-    Aig_Obj_t * pFanout;
-    int i, iFanout = -1, LevelCur, Level = 0;
-    Aig_ObjForEachFanout( p, pObj, pFanout, iFanout, i )
+    int i, iFanout = -1, FanoutId, LevelCur, Level = 0;
+    Aig_ObjForEachFanoutId( p, pObj, FanoutId, iFanout, i )
     {
-        LevelCur = Aig_ObjReverseLevel( p, pFanout );
+        LevelCur = Vec_IntGetEntry( p->vLevelR, FanoutId );
         Level = Abc_MaxInt( Level, LevelCur );
     }
     return Level + 1;
@@ -250,6 +249,8 @@ void Aig_ManUpdateReverseLevel( Aig_Man_t * p, Aig_Obj_t * pObjNew )
     int LevelOld, LevFanin, Lev, k;
     assert( p->vLevelR != NULL );
     assert( Aig_ObjIsNode(pObjNew) );
+    // ensure reverse levels array is large enough for all objects
+    Vec_IntFillExtra( p->vLevelR, Aig_ManObjNumMax(p), 0 );
     // allocate level if needed
     if ( p->vLevels == NULL )
         p->vLevels = Vec_VecAlloc( Aig_ManLevels(p) + 8 );