Open Source Software and Reproducibility in Computer Science
Computer science is a particularly friendly environment for releasing material in advance of publication.  In fact, there are a number of methods for doing so that provide a clear archival time-stamp on your work, including university technical reports, arXiv, and big repository sites like github and bitbucket.  Moreover, unlike many other disciplines, such pre-release almost never impairs your ability to build conference and journal publications on top of your released material.  In fact, you can typically release not just your code, but also your draft paper through the same mechanisms.

If you do such pre-release, you are essentially immune to plagiarism, because anybody who pirates your results will look like a fool with date-stamps marking their guilt for all to see.  It may not stop bottom-feeders from trying, but it will mean that nobody you care about (including reviewers) should take such an attempt seriously.

The only likely problem that you can run into is double-blind reviewing, as discussed in this question.  If that's not a major concern for you, or if you can use one of the mechanisms suggested in that question, then I see no likely downside in computer science publication.

On a side note, however: just because the code is available doesn't mean it's reproducible, as anybody who's spent significant time having a dependency-fight with poorly-document open source projects can attest.