From 0dcdbc2a6a4828a290f50679db16d138468bde05 Mon Sep 17 00:00:00 2001
From: Alan Mishchenko <alanmi@berkeley.edu>
Date: Thu, 19 Feb 2015 14:46:06 -0800
Subject: Performance bug fix in 'clp' (different way of removing redundant
 fanins).

---
 src/base/abci/abcCollapse.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

(limited to 'src/base/abci/abcCollapse.c')

diff --git a/src/base/abci/abcCollapse.c b/src/base/abci/abcCollapse.c
index 76a6f009..dada7765 100644
--- a/src/base/abci/abcCollapse.c
+++ b/src/base/abci/abcCollapse.c
@@ -31,10 +31,77 @@ ABC_NAMESPACE_IMPL_START
 static Abc_Ntk_t * Abc_NtkFromGlobalBdds( Abc_Ntk_t * pNtk );
 static Abc_Obj_t * Abc_NodeFromGlobalBdds( Abc_Ntk_t * pNtkNew, DdManager * dd, DdNode * bFunc );
 
+extern int Abc_NodeSupport( DdNode * bFunc, Vec_Str_t * vSupport, int nVars );
+
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////
 
+/**Function*************************************************************
+
+  Synopsis    [Makes nodes minimum base.]
+
+  Description [Returns the number of changed nodes.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeMinimumBase2( Abc_Obj_t * pNode )
+{
+    Vec_Str_t * vSupport;
+    Vec_Ptr_t * vFanins;
+    DdNode * bTemp;
+    int i, nVars;
+
+    assert( Abc_NtkIsBddLogic(pNode->pNtk) );
+    assert( Abc_ObjIsNode(pNode) );
+
+    // compute support
+    vSupport = Vec_StrAlloc( 10 );
+    nVars = Abc_NodeSupport( Cudd_Regular(pNode->pData), vSupport, Abc_ObjFaninNum(pNode) );
+    if ( nVars == Abc_ObjFaninNum(pNode) )
+    {
+        Vec_StrFree( vSupport );
+        return 0;
+    }
+
+    // add fanins
+    vFanins = Vec_PtrAlloc( Abc_ObjFaninNum(pNode) );
+    Abc_NodeCollectFanins( pNode, vFanins );
+    Vec_IntClear( &pNode->vFanins );
+    for ( i = 0; i < vFanins->nSize; i++ )
+        if ( vSupport->pArray[i] != 0 ) // useful
+            Vec_IntPush( &pNode->vFanins, Abc_ObjId((Abc_Obj_t *)vFanins->pArray[i]) );
+    assert( nVars == Abc_ObjFaninNum(pNode) );
+
+    // update the function of the node
+    pNode->pData = Extra_bddRemapUp( (DdManager *)pNode->pNtk->pManFunc, bTemp = (DdNode *)pNode->pData );   Cudd_Ref( (DdNode *)pNode->pData );
+    Cudd_RecursiveDeref( (DdManager *)pNode->pNtk->pManFunc, bTemp );
+    Vec_PtrFree( vFanins );
+    Vec_StrFree( vSupport );
+    return 1;
+}
+int Abc_NtkMinimumBase2( Abc_Ntk_t * pNtk )
+{
+    Abc_Obj_t * pNode, * pFanin;
+    int i, k, Counter;
+    assert( Abc_NtkIsBddLogic(pNtk) );
+    // remove all fanouts
+    Abc_NtkForEachObj( pNtk, pNode, i )
+        Vec_IntClear( &pNode->vFanouts );
+    // add useful fanins
+    Counter = 0;
+    Abc_NtkForEachNode( pNtk, pNode, i )
+        Counter += Abc_NodeMinimumBase2( pNode );
+    // add fanouts
+    Abc_NtkForEachObj( pNtk, pNode, i )
+        Abc_ObjForEachFanin( pNode, pFanin, k )
+            Vec_IntPush( &pFanin->vFanouts, Abc_ObjId(pNode) );
+    return Counter;
+}
+
 /**Function*************************************************************
 
   Synopsis    [Collapses the network.]
@@ -76,7 +143,7 @@ Abc_Ntk_t * Abc_NtkCollapse( Abc_Ntk_t * pNtk, int fBddSizeMax, int fDualRail, i
 //    pNtk->pManGlob = NULL;
 
     // make the network minimum base
-    Abc_NtkMinimumBase( pNtkNew );
+    Abc_NtkMinimumBase2( pNtkNew );
 
     if ( pNtk->pExdc )
         pNtkNew->pExdc = Abc_NtkDup( pNtk->pExdc );
-- 
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