Last response from AMD: "The vast majority of users using Ryzen for Linux code and development have reported very positive results. ... A small number of users have reported some isolated issues and conflicting observations. AMD is working with users individually to understand and resolve these issues."
I doubt there's any single root cause here. "I get crashes when running big compiles" is a classic symptom of hardware that is almost, but not quite, stable. This can be due to power delivery problems, thermals, marginal RAM, overclocks, faulty CPU (yeah, it happens sometimes) and so on.
https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Co...