RISC-V LLVM sync-up call 11th June 2020

For background on these calls, see

Reminder: the purpose is to co-ordinate between active contributors.
If you have support questions etc then it's best to post to llvm-dev.

We have a call every alternate Thursday at 4pm BST, via

I've created a shared calendar which may help in keeping track, which
is accessible at:
  * <https://calendar.google.com/calendar/b/1?cid=bG93cmlzYy5vcmdfMG41cGtlc2ZqY25wMGJoNWhwczFwMGJkODBAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbQ>
  * <https://calendar.google.com/calendar/ical/lowrisc.org_0n5pkesfjcnp0bh5hps1p0bd80%40group.calendar.google.com/public/basic.ics>

Issues to discuss today include the following:

* Improving compiler-rt testing of atomics https://reviews.llvm.org/D81348
* Anyone looking to implement -mpreferred-stack-boundary for RISC-V?
(question from Ana)
* Note recent psABI clarifications (Thanks Evandro!)
* Ping on -ffine-grained-bitfiled-access improvement patch
* libunwind on RV32 https://reviews.llvm.org/D80690
* strictfp/ftrapping-math patch https://reviews.llvm.org/D81391
* Bitmanip status
* Vector status
* Reminder: we now meet every other week. We'll meet again on Thu 25th June.
* No other topics were submitted, as always, please do submit things
you'd like to discuss