Presentation of an algorithm
I don't see any problem with reusing your own data from a previously published article, as long as it is cited properly. This would look like:


  We evaluated algorithm B using previously published data generated by
  algorithm A (Myself et al, 2010).


If the dataset is deposited somewhere along with the article describing algorithm A, it might have a DOI that you can also cite. If it isn't deposited, or hasn't been assigned a DOI, well now would be a good time to do that.

If the article describing algorithm A is more than a couple years old, nobody will think it is salami-slicing. And you only need to cite this article properly to rule out "self-plagiarism". Self-citation is an easy way to increase one's citation count, but it is definitely not unethical: you have to cite previous work relevant to your current article, even if it happens to be also from you.