//
// Subroutine of explainStoreExplanation
// Re-root the tree containing x, in such a way that
// the new root is x itself
//
void Egraph::expReRootOn ( Enode * x )
{
Enode * p = x;
Enode * parent = p->getExpParent( );
Enode * reason = p->getExpReason( );
x->setExpParent( NULL );
x->setExpReason( NULL );
while( parent != NULL )
{
// Save grandparent
Enode * grandparent = parent->getExpParent( );
// Save reason
Enode * saved_reason = reason;
reason = parent->getExpReason( );
// Reverse edge & reason
parent->setExpParent( p );
parent->setExpReason( saved_reason );
#ifdef PEDANTIC_DEBUG
assert( checkExpTree( parent ) );
#endif
// Move the two pointers
p = parent;
parent = grandparent;
}
}
//
// Subroutine of explain
// A step of explanation for x and y
//
void Egraph::expExplainAlongPath ( Enode * x, Enode * y )
{
Enode * v = expHighestNode( x );
Enode * to = expHighestNode( y );
while ( v != to )
{
Enode * p = v->getExpParent( );
assert( p != NULL );
Enode * r = v->getExpReason( );
// If it is not a congruence edge
if ( r != NULL )
{
if ( !isDup1( r ) )
{
assert( r->isTerm( ) );
explanation.push_back( r );
storeDup1( r );
}
}
// Otherwise it is a congruence edge
// This means that the edge is linking nodes
// like (v)f(a1,...,an) (p)f(b1,...,bn), and that
// a1,...,an = b1,...bn. For each pair ai,bi
// we have therefore to compute the reasons
else
{
assert( v->getCar( ) == p->getCar( ) );
assert( v->getArity( ) == p->getArity( ) );
expEnqueueArguments( v, p );
}
#ifdef PRODUCE_PROOF
if ( config.produce_inter > 0
&& config.logic != QF_AX )
{
cgraph.addCNode( v );
cgraph.addCNode( p );
cgraph.addCEdge( v, p, r );
}
#endif
expUnion( v, p );
v = expHighestNode( p );
}
}