.include common

common_anc_noloop( a:node, c1:node, c2:node )
common_anc_noloop( a, c1, c2 ) :- \
    anc_noloop( a, c1 ), \
    anc_noloop( a, c2 ).

goto_not_across_loop( g:node )
goto_not_across_loop( g ) :- \
    gotoS( g, l ), common_anc_noloop( _, g, l ).

goto_not_across_loop( G ), gotoS( G, L ), labelS( L, N ) ?
