From e162a26197b194e6b9adfcf455edb4312285c644 Mon Sep 17 00:00:00 2001
From: Alan Mishchenko <alanmi@berkeley.edu>
Date: Sat, 31 Jul 2021 22:46:47 -0700
Subject: Allow retiming to skip some logic.

---
 src/base/wln/wlnRetime.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

(limited to 'src/base/wln/wlnRetime.c')

diff --git a/src/base/wln/wlnRetime.c b/src/base/wln/wlnRetime.c
index 734ac194..5ccc1dd0 100644
--- a/src/base/wln/wlnRetime.c
+++ b/src/base/wln/wlnRetime.c
@@ -333,6 +333,55 @@ void Wln_RetFindSources( Wln_Ret_t * p )
 //    Vec_IntPrint( &p->vSources );
 }
 
+/**Function*************************************************************
+
+  Synopsis    [Mark paths from PIs to POs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Wln_RetMarkPaths_rec( Wln_Ntk_t * p, int iObj, int fVerbose )
+{
+    int k, iFanin, fPrev = 1;
+    if ( Wln_ObjIsTravIdPrevious(p, iObj) )
+        return 1;
+    if ( Wln_ObjIsTravIdCurrent(p, iObj) )
+        return 0;
+    if ( Wln_ObjIsCio(p, iObj) || Wln_ObjIsFf(p, iObj) )
+        return 0;
+    Wln_ObjForEachFanin( p, iObj, iFanin, k )
+        fPrev &= Wln_RetMarkPaths_rec( p, iFanin, fVerbose );
+    if ( fPrev )
+    {
+        Wln_ObjSetTravIdPrevious( p, iObj );
+        if ( Vec_IntEntry(&p->vInstIds, iObj) > 0 )
+        {
+            if ( fVerbose )
+                printf( "Updating delay %5d -> %5d : ", Vec_IntEntry(&p->vInstIds, iObj), 1 );
+            if ( fVerbose )
+                Wln_ObjPrint( p, iObj );
+            Vec_IntWriteEntry( &p->vInstIds, iObj, 1 );
+        }
+        return 1;
+    }
+    Wln_ObjSetTravIdCurrent( p, iObj );
+    return 0;
+}
+void Wln_RetMarkPaths( Wln_Ntk_t * p, int fVerbose )
+{
+    int i, iObj;
+    Wln_NtkIncrementTravId( p );
+    Wln_NtkIncrementTravId( p );
+    Wln_NtkForEachPi( p, iObj, i )
+        Wln_ObjSetTravIdPrevious( p, iObj );
+    Wln_NtkForEachPo( p, iObj, i )
+        Wln_RetMarkPaths_rec( p, Wln_ObjFanin0(p, iObj), fVerbose );
+}
+
 /**Function*************************************************************
 
   Synopsis    [Retimability check.]
@@ -571,7 +620,7 @@ void Wln_NtkRetimeCreateDelayInfo( Wln_Ntk_t * pNtk )
         printf( "Assuming default delays: 10 units for most nodes and 1 unit for bit-slice, concat, and buffers driving COs.\n" );
     }
 }
-Vec_Int_t * Wln_NtkRetime( Wln_Ntk_t * pNtk, int fSkipSimple, int fVerbose )
+Vec_Int_t * Wln_NtkRetime_int( Wln_Ntk_t * pNtk, int fSkipSimple, int fVerbose )
 {
     Wln_Ret_t * p = Wln_RetAlloc( pNtk );
     Vec_Int_t * vSources = &p->vSources;
@@ -666,6 +715,12 @@ Vec_Int_t * Wln_NtkRetime( Wln_Ntk_t * pNtk, int fSkipSimple, int fVerbose )
     }
     return vMoves;
 }
+Vec_Int_t * Wln_NtkRetime( Wln_Ntk_t * pNtk, int fIgnoreIO, int fSkipSimple, int fVerbose )
+{
+    if ( fIgnoreIO )
+        Wln_RetMarkPaths( pNtk, fVerbose );
+    return Wln_NtkRetime_int( pNtk, fSkipSimple, fVerbose );
+}
 
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
-- 
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