RISC-V LLVM sync-up call 8th July 2021

For background on these calls, see
<http://lists.llvm.org/pipermail/llvm-dev/2019-September/135087.html>.

Reminder: the purpose is to coordinate 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
<https://meet.google.com/ske-zcog-spp>. If you have topics to discuss,
please email me ahead and I can add them to the agenda.

We have a shared calendar that 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>

Agenda:

* Relaxed ISA string order, PR for toolchain document
  <https://github.com/riscv/riscv-toolchain-conventions/pull/14>
* New Tag_RISCV_reserved_register attribute, PR proposal for psABI
  <https://github.com/riscv/riscv-elf-psabi-doc/pull/195>
* Mapping symbols, PR proposal for psABI
  <https://github.com/riscv/riscv-elf-psabi-doc/pull/196>
* [RISCV] Unify the arch string parsing logic to RISCVArchStringParser.
  <https://reviews.llvm.org/D105168>
* Constant materialization improvements
  <https://reviews.llvm.org/D105509> <https://reviews.llvm.org/D105417>
* Target ABI checking and computing patches
  <https://reviews.llvm.org/D102582> <https://reviews.llvm.org/D105555>
* Revisit: Deducing default march and mabi
  <https://github.com/riscv/riscv-toolchain-conventions/issues/13>
* Revisit: Using a pragma for the RVV intrinsics header
  <https://reviews.llvm.org/D103228>
* AOB

Cheers,
Luís