Auto-sized UITableViewCells. This has *terrible* performance: a table with ~15 rows was noticeably jittery. It might be OK for very small tables with only a couple cells.

gistfile1.m

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
  /**
   * As long as your custom cell classes are laid out in Interface Builder and
   * have Autolayout constraints to the top and bottom edges of the content view,
   * the size of the cell can be computed based on how tall it needs to be.
   *
   * USE AT YOUR OWN RISK. This causes a noticable performance hit on a table of
   * only about 15 cells. It might work OK on tables with only a few cells, but
   * be sure to test it for your actual use case. I'm only sharing this on gist
   * because I found it interesting.
   */
  UITableViewCell *cell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
  [cell layoutIfNeeded];
  CGSize size = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
  if (size.height > 0) {
    return size.height;
  }
  else {
    return [super tableView:tableView heightForRowAtIndexPath:indexPath];
  }
}