Thanks for the update. I was encouraging some of the people who were going to be at HACS to address this but I hadn't heard the latest progress. Unfortunately I couldn't be there myself.
If I remember correctly, Chandler was the one writing down the draft for LLVM developers to comment on LLVM-side. Unfortunately, if you Google his name and the relevant keywords, the results are full of his work on speculative load hardening.
Someone who read the LLVM mailing-list attentively should have seen it and may have a link.
