@tjw On the day Opteron was supposed to tape out, a colleague discovered a logic bug. After some analysis, we figured out we could fix it by disconnecting a wire from one gate and attaching it to another. But running through or design flow would take days, and the ripple effect of changing connectivity could cause more problems. So I loaded the chip mask into VIM and modified the polygons directly, then we taped it out.
Don’t remember for sure, but I don’t think we told management 🙂