[morcheeba]

>lower the respin costs

You might be interested in structured ASICs, which allow for substantial reuse of masks between different products. At the extreme was a via-only definition product where all interconnects were specified with one mask (and the via masks were among the cheapest to make since they are very uniform).

In regular ASIC development, we've had extra unrouted transistors available to wire in case of a mistake (so hopefully the respin involved just some new metal layers). Techniques like FIB can be used to test fixes to lower the number of respins, too. I'm not sure how much of this was automated to maximize chances of being useful.

https://en.wikipedia.org/wiki/Structured_ASIC_platform