RISC-V LLVM sync-up call 28th May 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 each 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:

* -misa-version. See
  <https://sourceware.org/pipermail/binutils/2020-April/110714.html> and v2
  proposal <https://sourceware.org/pipermail/binutils/2020-May/110971.html>
* SiFive interrupt attributes and CLIC CSRs <https://reviews.llvm.org/D79521>,
* bitmanip patch stack <https://reviews.llvm.org/D79870>
* Other in-flight patches and planned updates to highlight
  * D80367 print absolute targets of branch instructions
  * libunwind for RV32 https://reviews.llvm.org/D80690
  * Improvements to constant materialisation https://reviews.llvm.org/D79492
* Meeting frequency (moving to a cadence of every other week rather
than every week?)
* No other topics were submitted, as always, please do submit things
you'd like to discuss