[llvm-dev] LLVM Weekly - #403, September 20th 2021

[Alex Bradbury via llvm-dev]

LLVM Weekly - #403, September 20th 2021
=======================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/403>.

Welcome to the four hundred and third issue of LLVM Weekly, a weekly
newsletter (published every Monday) covering developments in LLVM, Clang, and
related projects. LLVM Weekly is brought to you by [Alex
Bradbury](https://www.linkedin.com/in/alex-bradbury/). Subscribe to future
issues at <http://llvmweekly.org> and pass it on to anyone else you think may
be interested. Please send any tips or feedback to <asb at asbradbury.org>, or
@llvmweekly or @asbradbury on Twitter.


## News and articles from around the web

The recording from the LLVM Distributors' Conf is [available on
YouTube](https://www.youtube.com/watch?v=UMDRAmmDBgM).

The call for proposals for the 2021 LLVM Developers' Meeting has been
[extended to September
27th](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152717.html).


## On the mailing lists

* LLVM 13.0.0-rc3 [has been
  tagged](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152657.html).
  Tom Stellard also sent a
  [reminder](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152698.html)
  to put release-13.0.0 in the 'Blocks' field of bugs that you want fixed in
  the 13.0.0 release.

* Petr Hosek proposed [unifying the names of variables used for results of
  CMake
  checks](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152791.html),
  which may allow better deduplication of checks or removal of unnecessary
  ones.

* Tom Stellard [proposes deprecating
  config.guess](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152717.html).

* Chris Bieneman [followed
  up](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152764.html) on
  the previous thread on a multi-call ("busybox style") LLVM binary to share a
  prototype of the idea.

* Momchil Velikov shared an RFC proposal for [adding a simple GVN hoisting
  transform](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152665.html)
  to catch common cases, without enabling the full GVNHoist pass. This
  resulted in some
  [detailed](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152684.html)
  [responses](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152679.html)
  from Philip Reames.

* Arthur Eubanks suggested [saving memory by clearing the Clang AST before
  running backend optimisations and
  codegen](https://lists.llvm.org/pipermail/cfe-dev/2021-September/068930.html).

* Zeson asked about [some of the challenges of i64 being the only legal type
  on 64-bit
  RISC-V](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152738.html).
  [Craig
  Topper](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152755.html)
  and [Alex
  Bradbury](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152803.html)
  responded with thoughts.

* Kuba Mracek
  [pinged](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152654.html)
  for any additional feedback on the introduction of conditional references
  between globals in LLVM IR.

* "bd1976" posted an RFC on [emitting additional metadata to facilitate ELF
  hotpatching](https://lists.llvm.org/pipermail/llvm-dev/2021-September/152697.html).


## LLVM commits

* The PowerPC backend can now selected prefixed loads/stores (loads/stories
  with a offset fitting into a 34-bit immediate).
  [5041a48](https://reviews.llvm.org/rG5041a485b948).

* `LLVM_ENABLE_PER_TARGET_RUNTIME_DIR` was enabled by default on Linux.
  [f9dbca6](https://reviews.llvm.org/rGf9dbca68d48e).

* The Arm backend gained a mitigation for CVE-2021-35465 (present in the
  Cortex-M33, M35P, and M55).
  [1bd5ea9](https://reviews.llvm.org/rG1bd5ea968e92).

* Finalisation and deallocation actions were added to ORC.
  [78b083d](https://reviews.llvm.org/rG78b083dbb725).

* A reduce operands pass was added to llvm-reduce.
  [f18c073](https://reviews.llvm.org/rGf18c0739b307).


## Clang commits

* A new readability-container-data-pointer check was introduced.
  [d0d9e6f](https://reviews.llvm.org/rGd0d9e6f0849b).

* Support was added for delimited escape sequences `\x{XXXX}`, `\u{XXXX}`, and
  `\o{OOOO}`. [274adcb](https://reviews.llvm.org/rG274adcb86634).

* Information about C99 was added to Clang's C status page.
  [101c3de](https://reviews.llvm.org/rG101c3de39fbc).


## Other project commits

* Following on from a [previous RFC
  discussion](https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html),
  global state was removed from the LLD/COFF linker.
  [6f7483b](https://reviews.llvm.org/rG6f7483b1ece4).

* Documentation was added for flang frontend driver plugins.
  [7acf929](https://reviews.llvm.org/rG7acf92943b78).

* A clspv (a compiler for compiling OpenCL C to Vulkan SPIR-V) target was
  added to libclc. [21427b8](https://reviews.llvm.org/rG21427b8eb8e7).