RISC-V LLVM sync-up call 21st January 2021

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 GMT, via

We have a shared calendar which may help in keeping track, which is
accessible at:
* <https://calendar.google.com/calendar/b/1?cid=bG93cmlzYy5vcmdfMG41cGtlc2ZqY25wMGJoNWhwczFwMGJkODBAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbQ&gt;
* <https://calendar.google.com/calendar/ical/lowrisc.org_0n5pkesfjcnp0bh5hps1p0bd80%40group.calendar.google.com/public/basic.ics&gt;

Topics to discuss today include the following:
* Patches to prioritise for LLVM 12 (branching on Jan 26th)
  * D94403 architecture extension macros?
  * Please highlight patches you'd particularly like to get
reviewed+merged before then
* [Simon] Refactoring of extension version numbers - introducing a
single location for version number parsing+handling. (see
https://reviews.llvm.org/D94403 and ⚙ D94931 [RISCV] Add attribute support for all supported extensions)
* Landing bitmanip 0.93 changes
* Any topics related to ongoing vector work?
  * See also: Fraser's incorrect codegen test case
⚙ D95025 [RISCV] Add a test showing incorrect codegen
* Any other business?
* Next call: 4th Feb 2021