This: https://news.ycombinator.com/item?id=49226923

It’s actually pretty good at this if you have some very specific constraints and objective.

tbh, it probably works. I'm vibe-coding a thing and just told it to figure out why it runs so slow: put in some optimizations. It ran some tests and stopped loading an entire-something at opening because there's no value to doing that.

It does a pretty good job being put into a loop of "try to optimize for X" then "test and audit your code" then repeat.