/**CFile****************************************************************
FileName [ivyRwt.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [And-Inverter Graph package.]
Synopsis [Rewriting based on precomputation.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - May 11, 2006.]
Revision [$Id: ivyRwt.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
***********************************************************************/
#include "ivy.h"
#include "deco.h"
#include "rwt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static unsigned Ivy_NodeGetTruth( Ivy_Obj_t * pObj, int * pNums, int nNums );
static int Ivy_NodeRewrite( Ivy_Man_t * pMan, Rwt_Man_t * p, Ivy_Obj_t * pNode, int fUpdateLevel, int fUseZeroCost );
static Dec_Graph_t * Rwt_CutEvaluate( Ivy_Man_t * pMan, Rwt_Man_t * p, Ivy_Obj_t * pRoot,
Vec_Ptr_t * vFaninsCur, int nNodesSaved, int LevelMax, int * pGainBest, unsigned uTruth );
static int Ivy_GraphToNetworkCount( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Dec_Graph_t * pGraph, int NodeMax, int LevelMax );
static void Ivy_GraphUpdateNetwork( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Dec_Graph_t * pGraph, int fUpdateLevel, int nGain );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs incremental rewriting of the AIG.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManRewritePre( Ivy_Man_t * p, int fUpdateLevel, int fUseZeroCost, int fVerbose )
{
Rwt_Man_t * pManRwt;
Ivy_Obj_t * pNode;
int i, nNodes, nGain;
int clk, clkStart = clock();
// start the rewriting manager
pManRwt = Rwt_ManStart( 0 );
p->pData = pManRwt;
if ( pManRwt == NULL )
return 0;
// create fanouts
if ( fUpdateLevel && p->fFanout == 0 )
Ivy_ManStartFanout( p );
// compute the reverse levels if level update is requested
if ( fUpdateLevel )
Ivy_ManRequiredLevels( p );
// set the number of levels
// p->nLevelMax = Ivy_ManLevels( p );
// resynthesize each node once
nNodes = Ivy_ManObjIdMax(p);
Ivy_ManForEachNode( p, pNode, i )
{
// fix the fanin buffer problem
Ivy_NodeFixBufferFanins( p, pNode, 1 );
if ( Ivy_ObjIsBuf(pNode) )
continue;
// stop if all nodes have been tried once
if ( i > nNodes )
break;
// for each cut, try to resynthesize it
nGain = Ivy_NodeRewrite( p, pManRwt, pNode, fUpdateLevel, fUseZeroCost );
if ( nGain > 0 || (nGain == 0 && fUseZeroCost) )
{
Dec_Graph_t * pGraph = (Dec_Graph_t *)Rwt_ManReadDecs(pManRwt);
int fCompl = Rwt_ManReadCompl(pManRwt);
/*
{
Ivy_Obj_t * pObj;
int i;
printf( "USING: (" );
Vec_PtrForEachEntry( Ivy_Obj_t *, Rwt_ManReadLeaves(pManRwt), pObj, i )
printf( "%d ", Ivy_ObjFanoutNum(Ivy_Regular(pObj)) );
printf( ") Gain = %d.\n", nGain );
}
if ( nGain > 0 )
{ // print stats on the MFFC
extern void Ivy_NodeMffcConeSuppPrint( Ivy_Obj_t * pNode );
printf( "Node %6d : Gain = %4d ", pNode->Id, nGain );
Ivy_NodeMffcConeSuppPrint( pNode );
}
*/
// complement the FF if needed
clk = clock();
if ( fCompl ) Dec_GraphComplement( pGraph );
Ivy_GraphUpdateNetwork( p, pNode, pGraph, fUpdateLevel, nGain );
if ( fCompl ) Dec_GraphComplement( pGraph );
Rwt_ManAddTimeUpdate( pManRwt, clock() - clk );
}
}
Rwt_ManAddTimeTotal( pManRwt, clock() - clkStart );
// print stats
if ( fVerbose )
Rwt_ManPrintStats( pManRwt );
// delete the managers
Rwt_ManStop( pManRwt );
p->pData = NULL;
// fix the levels
if ( fUpdateLevel )
Vec_IntFree( p->vRequired ), p->vRequired = NULL;
else
Ivy_ManResetLevels( p );
// check
if ( (i = Ivy_ManCleanup(p)) )
printf( "Cleanup after rewriting removed %d dangling nodes.\n", i );
if ( !Ivy_ManCheck(p) )
printf( "Ivy_ManRewritePre(): The check has failed.\n" );
return 1;
}
/**Function*************************************************************
Synopsis [Performs rewriting for one node.]
Description [This procedure considers all the cuts computed for the node
and tries to rewrite each of them using the "forest" of different AIG
structures precomputed and stored in the RWR manager.
Determines the best rewriting and computes the gain in the number of AIG
nodes in the final network. In the end, p->vFanins contains information
about the best cut that can be used for rewriting, while p->pGraph gives
the decomposition dag (represented using decomposition graph data structure).
Returns gain in the number of nodes or -1 if node cannot be rewritten.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_NodeRewrite( Ivy_Man_t * pMan, Rwt_Man_t * p, Ivy_Obj_t * pNode, int fUpdateLevel, int fUseZeroCost )
{
int fVeryVerbose = 0;
Dec_Graph_t * pGraph;
Ivy_Store_t * pStore;
Ivy_Cut_t * pCut;
Ivy_Obj_t * pFanin;
unsigned uPhase;
unsigned uTruthBest = 0; // Suppress "might be used uninitialized"
unsigned uTruth;
char * pPerm;
int Required, nNodesSaved;
int nNodesSaveCur = -1; // Suppress "might be used uninitialized"
int i, c, GainCur, GainBest = -1;
int clk, clk2;
p->nNodesConsidered++;
// get the required times
Required = fUpdateLevel? Vec_IntEntry( pMan->vRequired, pNode->Id ) : 1000000;
// get the node's cuts
clk = clock();
pStore = Ivy_NodeFindCutsAll( pMan, pNode, 5 );
p->timeCut += clock() - clk;
// go through the cuts
clk = clock();
for ( c = 1; c < pStore->nCuts; c++ )
{
pCut = pStore->pCuts + c;
// consider only 4-input cuts
if ( pCut->nSize != 4 )
continue;
// skip the cuts with buffers
for ( i = 0; i < (int)pCut->nSize; i++ )
if ( Ivy_ObjIsBuf( Ivy_ManObj(pMan, pCut->pArray[i]) ) )
break;
if ( i != pCut->nSize )
{
p->nCutsBad++;
continue;
}
p->nCutsGood++;
// get the fanin permutation
clk2 = clock();
uTruth = 0xFFFF & Ivy_NodeGetTruth( pNode, pCut->pArray, pCut->nSize ); // truth table
p->timeTruth += clock() - clk2;
pPerm = p->pPerms4[ (int) p->pPerms[uTruth] ];
uPhase = p->pPhases[uTruth];
// collect fanins with the corresponding permutation/phase
Vec_PtrClear( p->vFaninsCur );
Vec_PtrFill( p->vFaninsCur, (int)pCut->nSize, 0 );
for ( i = 0; i < (int)pCut->nSize; i++ )
{
pFanin = Ivy_ManObj( pMan, pCut->pArray[(int)pPerm[i]] );
assert( Ivy_ObjIsNode(pFanin) || Ivy_ObjIsCi(pFanin) );
pFanin = Ivy_NotCond(pFanin, ((uPhase & (1<<i)) > 0) );
Vec_PtrWriteEntry( p->vFaninsCur, i, pFanin );
}
clk2 = clock();
/*
printf( "Considering: (" );
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFaninsCur, pFanin, i )
printf( "%d ", Ivy_ObjFanoutNum(Ivy_Regular(pFanin)) );
printf( ")\n" );
*/
// mark the fanin boundary
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFaninsCur, pFanin, i )
Ivy_ObjRefsInc( Ivy_Regular(pFanin) );
// label MFFC with current ID
Ivy_ManIncrementTravId( pMan );
nNodesSaved = Ivy_ObjMffcLabel( pMan, pNode );
// unmark the fanin boundary
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFaninsCur, pFanin, i )
Ivy_ObjRefsDec( Ivy_Regular(pFanin) );
p->timeMffc += clock() - clk2;
// evaluate the cut
clk2 = clock();
pGraph = Rwt_CutEvaluate( pMan, p, pNode, p->vFaninsCur, nNodesSaved, Required, &GainCur, uTruth );
p->timeEval += clock() - clk2;
// check if the cut is better than the current best one
if ( pGraph != NULL && GainBest < GainCur )
{
// save this form
nNodesSaveCur = nNodesSaved;
GainBest = GainCur;
p->pGraph = pGraph;
p->fCompl = ((uPhase & (1<<4)) > 0);
uTruthBest = uTruth;
// collect fanins in the
Vec_PtrClear( p->vFanins );
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFaninsCur, pFanin, i )
Vec_PtrPush( p->vFanins, pFanin );
}
}
p->timeRes += clock() - clk;
if ( GainBest == -1 )
return -1;
// printf( "%d", nNodesSaveCur - GainBest );
/*
if ( GainBest > 0 )
{
if ( Rwt_CutIsintean( pNode, p->vFanins ) )
printf( "b" );
else
{
printf( "Node %d : ", pNode->Id );
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFanins, pFanin, i )
printf( "%d ", Ivy_Regular(pFanin)->Id );
printf( "a" );
}
}
*/
/*
if ( GainBest > 0 )
if ( p->fCompl )
printf( "c" );
else
printf( "." );
*/
// copy the leaves
Vec_PtrForEachEntry( Ivy_Obj_t *, p->vFanins, pFanin, i )
Dec_GraphNode((Dec_Graph_t *)p->pGraph, i)->pFunc = pFanin;
p->nScores[p->pMap[uTruthBest]]++;
p->nNodesGained += GainBest;
if ( fUseZeroCost || GainBest > 0 )
p->nNodesRewritten++;
// report the progress
if ( fVeryVerbose && GainBest > 0 )
{
printf( "Node %6d : ", Ivy_ObjId(pNode) );
printf( "Fanins = %d. ", p->vFanins->nSize );
printf( "Save = %d. ", nNodesSaveCur );
printf( "Add = %d. ", nNodesSaveCur-GainBest );
printf( "GAIN = %d. ", GainBest );
printf( "Cone = %d. ", p->pGraph? Dec_GraphNodeNum((Dec_Graph_t *)p->pGraph) : 0 );
printf( "Class = %d. ", p->pMap[uTruthBest] );
printf( "\n" );
}
return GainBest;
}
/**Function*************************************************************
Synopsis [Computes the truth table.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
unsigned Ivy_NodeGetTruth_rec( Ivy_Obj_t * pObj, int * pNums, int nNums )
{
static unsigned uMasks[5] = { 0xAAAAAAAA, 0xCCCCCCCC, 0xF0F0F0F0, 0xFF00FF00, 0xFFFF0000 };
unsigned uTruth0, uTruth1;
int i;
for ( i = 0; i < nNums; i++ )
if ( pObj->Id == pNums[i] )
return uMasks[i];
assert( Ivy_ObjIsNode(pObj) || Ivy_ObjIsBuf(pObj) );
uTruth0 = Ivy_NodeGetTruth_rec( Ivy_ObjFanin0(pObj), pNums, nNums );
if ( Ivy_ObjFaninC0(pObj) )
uTruth0 = ~uTruth0;
if ( Ivy_ObjIsBuf(pObj) )
return uTruth0;
uTruth1 = Ivy_NodeGetTruth_rec( Ivy_ObjFanin1(pObj), pNums, nNums );
if ( Ivy_ObjFaninC1(pObj) )
uTruth1 = ~uTruth1;
return uTruth0 & uTruth1;
}
/**Function*************************************************************
Synopsis [Computes the truth table.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
unsigned Ivy_NodeGetTruth( Ivy_Obj_t * pObj, int * pNums, int nNums )
{
assert( nNums < 6 );
return Ivy_NodeGetTruth_rec( pObj, pNums, nNums );
}
/**Function*************************************************************
Synopsis [Evaluates the cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Dec_Graph_t * Rwt_CutEvaluate( Ivy_Man_t * pMan, Rwt_Man_t * p, Ivy_Obj_t * pRoot, Vec_Ptr_t * vFaninsCur, int nNodesSaved, int LevelMax, int * pGainBest, unsigned uTruth )
{
Vec_Ptr_t * vSubgraphs;
Dec_Graph_t * pGraphBest = NULL; // Suppress "might be used uninitialized"
Dec_Graph_t * pGraphCur;
Rwt_Node_t * pNode, * pFanin;
int nNodesAdded, GainBest, i, k;
// find the matching class of subgraphs
vSubgraphs = Vec_VecEntry( p->vClasses, p->pMap[uTruth] );
p->nSubgraphs += vSubgraphs->nSize;
// determine the best subgraph
GainBest = -1;
Vec_PtrForEachEntry( Rwt_Node_t *, vSubgraphs, pNode, i )
{
// get the current graph
pGraphCur = (Dec_Graph_t *)pNode->pNext;
// copy the leaves
Vec_PtrForEachEntry( Rwt_Node_t *, vFaninsCur, pFanin, k )
Dec_GraphNode(pGraphCur, k)->pFunc = pFanin;
// detect how many unlabeled nodes will be reused
nNodesAdded = Ivy_GraphToNetworkCount( pMan, pRoot, pGraphCur, nNodesSaved, LevelMax );
if ( nNodesAdded == -1 )
continue;
assert( nNodesSaved >= nNodesAdded );
// count the gain at this node
if ( GainBest < nNodesSaved - nNodesAdded )
{
GainBest = nNodesSaved - nNodesAdded;
pGraphBest = pGraphCur;
}
}
if ( GainBest == -1 )
return NULL;
*pGainBest = GainBest;
return pGraphBest;
}
/**Function*************************************************************
Synopsis [Counts the number of new nodes added when using this graph.]
Description [AIG nodes for the fanins should be assigned to pNode->pFunc
of the leaves of the graph before calling this procedure.
Returns -1 if the number of nodes and levels exceeded the given limit or
the number of levels exceeded the maximum allowed level.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_GraphToNetworkCount( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Dec_Graph_t * pGraph, int NodeMax, int LevelMax )
{
Dec_Node_t * pNode, * pNode0, * pNode1;
Ivy_Obj_t * pAnd, * pAnd0, * pAnd1;
int i, Counter, LevelNew, LevelOld;
// check for constant function or a literal
if ( Dec_GraphIsConst(pGraph) || Dec_GraphIsVar(pGraph) )
return 0;
// set the levels of the leaves
Dec_GraphForEachLeaf( pGraph, pNode, i )
pNode->Level = Ivy_Regular((Ivy_Obj_t *)pNode->pFunc)->Level;
// compute the AIG size after adding the internal nodes
Counter = 0;
Dec_GraphForEachNode( pGraph, pNode, i )
{
// get the children of this node
pNode0 = Dec_GraphNode( pGraph, pNode->eEdge0.Node );
pNode1 = Dec_GraphNode( pGraph, pNode->eEdge1.Node );
// get the AIG nodes corresponding to the children
pAnd0 = (Ivy_Obj_t *)pNode0->pFunc;
pAnd1 = (Ivy_Obj_t *)pNode1->pFunc;
if ( pAnd0 && pAnd1 )
{
// if they are both present, find the resulting node
pAnd0 = Ivy_NotCond( pAnd0, pNode->eEdge0.fCompl );
pAnd1 = Ivy_NotCond( pAnd1, pNode->eEdge1.fCompl );
pAnd = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, pAnd0, pAnd1, IVY_AND, IVY_INIT_NONE) );
// return -1 if the node is the same as the original root
if ( Ivy_Regular(pAnd) == pRoot )
return -1;
}
else
pAnd = NULL;
// count the number of added nodes
if ( pAnd == NULL || Ivy_ObjIsTravIdCurrent(p, Ivy_Regular(pAnd)) )
{
if ( ++Counter > NodeMax )
return -1;
}
// count the number of new levels
LevelNew = 1 + RWT_MAX( pNode0->Level, pNode1->Level );
if ( pAnd )
{
if ( Ivy_Regular(pAnd) == p->pConst1 )
LevelNew = 0;
else if ( Ivy_Regular(pAnd) == Ivy_Regular(pAnd0) )
LevelNew = (int)Ivy_Regular(pAnd0)->Level;
else if ( Ivy_Regular(pAnd) == Ivy_Regular(pAnd1) )
LevelNew = (int)Ivy_Regular(pAnd1)->Level;
LevelOld = (int)Ivy_Regular(pAnd)->Level;
// assert( LevelNew == LevelOld );
}
if ( LevelNew > LevelMax )
return -1;
pNode->pFunc = pAnd;
pNode->Level = LevelNew;
}
return Counter;
}
/**Function*************************************************************
Synopsis [Transforms the decomposition graph into the AIG.]
Description [AIG nodes for the fanins should be assigned to pNode->pFunc
of the leaves of the graph before calling this procedure.]
SideEffects []
SeeAlso []
***********************************************************************/
Ivy_Obj_t * Ivy_GraphToNetwork( Ivy_Man_t * p, Dec_Graph_t * pGraph )
{
Ivy_Obj_t * pAnd0, * pAnd1;
Dec_Node_t * pNode = NULL; // Suppress "might be used uninitialized"
int i;
// check for constant function
if ( Dec_GraphIsConst(pGraph) )
return Ivy_NotCond( Ivy_ManConst1(p), Dec_GraphIsComplement(pGraph) );
// check for a literal
if ( Dec_GraphIsVar(pGraph) )
return Ivy_NotCond( (Ivy_Obj_t *)Dec_GraphVar(pGraph)->pFunc, Dec_GraphIsComplement(pGraph) );
// build the AIG nodes corresponding to the AND gates of the graph
Dec_GraphForEachNode( pGraph, pNode, i )
{
pAnd0 = Ivy_NotCond( (Ivy_Obj_t *)Dec_GraphNode(pGraph, pNode->eEdge0.Node)->pFunc, pNode->eEdge0.fCompl );
pAnd1 = Ivy_NotCond( (Ivy_Obj_t *)Dec_GraphNode(pGraph, pNode->eEdge1.Node)->pFunc, pNode->eEdge1.fCompl );
pNode->pFunc = Ivy_And( p, pAnd0, pAnd1 );
}
// complement the result if necessary
return Ivy_NotCond( (Ivy_Obj_t *)pNode->pFunc, Dec_GraphIsComplement(pGraph) );
}
/**Function*************************************************************
Synopsis [Replaces MFFC of the node by the new factored form.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_GraphUpdateNetwork( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Dec_Graph_t * pGraph, int fUpdateLevel, int nGain )
{
Ivy_Obj_t * pRootNew;
int nNodesNew, nNodesOld, Required;
Required = fUpdateLevel? Vec_IntEntry( p->vRequired, pRoot->Id ) : 1000000;
nNodesOld = Ivy_ManNodeNum(p);
// create the new structure of nodes
pRootNew = Ivy_GraphToNetwork( p, pGraph );
assert( (int)Ivy_Regular(pRootNew)->Level <= Required );
// if ( Ivy_Regular(pRootNew)->Level == Required )
// printf( "Difference %d.\n", Ivy_Regular(pRootNew)->Level - Required );
// remove the old nodes
// Ivy_AigReplace( pMan->pManFunc, pRoot, pRootNew, fUpdateLevel );
/*
if ( Ivy_IsComplement(pRootNew) )
printf( "c" );
else
printf( "d" );
if ( Ivy_ObjRefs(Ivy_Regular(pRootNew)) > 0 )
printf( "%d", Ivy_ObjRefs(Ivy_Regular(pRootNew)) );
printf( " " );
*/
Ivy_ObjReplace( p, pRoot, pRootNew, 1, 0, 1 );
// compare the gains
nNodesNew = Ivy_ManNodeNum(p);
assert( nGain <= nNodesOld - nNodesNew );
// propagate the buffer
Ivy_ManPropagateBuffers( p, 1 );
}
/**Function*************************************************************
Synopsis [Replaces MFFC of the node by the new factored form.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_GraphUpdateNetwork3( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Dec_Graph_t * pGraph, int fUpdateLevel, int nGain )
{
Ivy_Obj_t * pRootNew, * pFanin;
int nNodesNew, nNodesOld, i, nRefsOld;
nNodesOld = Ivy_ManNodeNum(p);
//printf( "Before = %d. ", Ivy_ManNodeNum(p) );
// mark the cut
Vec_PtrForEachEntry( Ivy_Obj_t *, ((Rwt_Man_t *)p->pData)->vFanins, pFanin, i )
Ivy_ObjRefsInc( Ivy_Regular(pFanin) );
// deref the old cone
nRefsOld = pRoot->nRefs;
pRoot->nRefs = 0;
Ivy_ObjDelete_rec( p, pRoot, 0 );
pRoot->nRefs = nRefsOld;
// unmark the cut
Vec_PtrForEachEntry( Ivy_Obj_t *, ((Rwt_Man_t *)p->pData)->vFanins, pFanin, i )
Ivy_ObjRefsDec( Ivy_Regular(pFanin) );
//printf( "Deref = %d. ", Ivy_ManNodeNum(p) );
// create the new structure of nodes
pRootNew = Ivy_GraphToNetwork( p, pGraph );
//printf( "Create = %d. ", Ivy_ManNodeNum(p) );
// remove the old nodes
// Ivy_AigReplace( pMan->pManFunc, pRoot, pRootNew, fUpdateLevel );
/*
if ( Ivy_IsComplement(pRootNew) )
printf( "c" );
else
printf( "d" );
if ( Ivy_ObjRefs(Ivy_Regular(pRootNew)) > 0 )
printf( "%d", Ivy_ObjRefs(Ivy_Regular(pRootNew)) );
printf( " " );
*/
Ivy_ObjReplace( p, pRoot, pRootNew, 0, 0, 1 );
//printf( "Replace = %d. ", Ivy_ManNodeNum(p) );
// delete remaining dangling nodes
Vec_PtrForEachEntry( Ivy_Obj_t *, ((Rwt_Man_t *)p->pData)->vFanins, pFanin, i )
{
pFanin = Ivy_Regular(pFanin);
if ( !Ivy_ObjIsNone(pFanin) && Ivy_ObjRefs(pFanin) == 0 )
Ivy_ObjDelete_rec( p, pFanin, 1 );
}
//printf( "Deref = %d. ", Ivy_ManNodeNum(p) );
//printf( "\n" );
// compare the gains
nNodesNew = Ivy_ManNodeNum(p);
assert( nGain <= nNodesOld - nNodesNew );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END