JDK-8376171 introduces storage of the identity hashCode in the markWord. There is still some follow-up work to be done to improve robustness and maintainability, including but not limited to:
- Adding assertions to the CAS-setting of the hash in the markWord
- Breaking the loop if the CAS results in a conflict
- SSA-ing the hash variable
- Possibly introducing a markWord::has_hash to improve legibility