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-rw-r--r--src/aig/gia/giaSweep.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/src/aig/gia/giaSweep.c b/src/aig/gia/giaSweep.c
index 1d66caee..344eca44 100644
--- a/src/aig/gia/giaSweep.c
+++ b/src/aig/gia/giaSweep.c
@@ -388,6 +388,14 @@ Vec_Int_t * Gia_ManComputeCarryOuts( Gia_Man_t * p )
Tim_Man_t * pManTime = (Tim_Man_t *)p->pManTime;
int i, iLast, iBox, nBoxes = Tim_ManBoxNum( pManTime );
Vec_Int_t * vCarryOuts = Vec_IntAlloc( nBoxes );
+
+ // Create and populare reference count (and free later) only if not already
+ // done.
+ int createRefs = (p->pRefs == NULL);
+ if (createRefs) {
+ Gia_ManCreateRefs( p );
+ }
+
for ( i = 0; i < nBoxes; i++ )
{
iLast = Tim_ManBoxInputLast( pManTime, i );
@@ -398,9 +406,24 @@ Vec_Int_t * Gia_ManComputeCarryOuts( Gia_Man_t * p )
if ( iBox == -1 )
continue;
assert( Gia_ObjIsCi(pObj) );
- if ( Gia_ObjCioId(pObj) == Tim_ManBoxOutputLast(pManTime, iBox) )
+ if ( Gia_ObjCioId(pObj) == Tim_ManBoxOutputLast(pManTime, iBox) ) {
Vec_IntPush( vCarryOuts, Gia_ObjId(p, pObj) );
+
+ // We have identified a carry connection. Check if the carry out
+ // of the destination box is unconnected. If so then add it to
+ // the carry list as well.
+ iLast = Tim_ManBoxOutputLast(pManTime, i);
+ pObj = Gia_ManCi(p, iLast);
+ if ( Gia_ObjRefNum(p, pObj) == 0 ) {
+ Vec_IntPush( vCarryOuts, Gia_ObjId(p, pObj) );
+ }
+ }
+ }
+
+ if (createRefs) {
+ ABC_FREE( p->pRefs );
}
+
return vCarryOuts;
}