<?php
if( $loop->have_posts() ):
  while ( $loop->have_posts() ):
    $loop->the_post();
          // Do stuff for results
    echo '<h2>' . the_title() . '</h2>';

    // Check for tag
    if(has_tag($tag) { output HTML if true }

  endwhile;
else:
  echo "No Results!";
endif;

?>