[llvm-dev] LLVM Weekly - #409, November 1st 2021

Alex Bradbury via llvm-dev
Mon, 01 Nov 2021 18:10:22 -0000

LLVM Weekly - #409, November 1st 2021
====================================
If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/409>.

Welcome to the four hundred and ninth 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 submission form for Round Tables at the 2021 LLVM Dev Meeting [is now
available](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153411.html).

Videos from CppCon 2021 [have started to be
posted](https://pages.jetbrains.com/cppcon2021).

Stefan Gränitz blogged about [porting the Cling C++ REPL to LLVM 13 and
ORCv2](https://weliveindetail.github.io/blog/post/2021/10/27/cling-llvm13-orcv2.html).


## On the mailing lists

* Anton Korobeynikov provided an [update on bugzilla

migration](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153457.html),
  reporting "I believe we were able to work-around the majority of GitHub
  deficiencies (at least those that were show-stoppers). We are checking the
  results. Hopefully I will be able to return to you with the final migration
  roadmap soon."

* Carlos Galvez started an RFC thread on [contributing Autosar C++14
  guidelines support to

clang-tidy](https://lists.llvm.org/pipermail/cfe-dev/2021-October/069176.html).

* James Nagourne
  [proposed](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153479.html)
  gneeralising Hexagon's VLIWMachineScheduler so it can be used by other
  targets.

* Nimit Singhania started a thread to [propose adding two static analyses to
  help detect performance issues in GPU
  programs](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153412.html).

* Luís Ferreira posted to discuss [upstreaming an LLDB language plugin for
  D](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153399.html).

* To enable better LLDB+QEMU integration, Pavel Labath
  [proposed](https://lists.llvm.org/pipermail/lldb-dev/2021-October/017106.html)
  a new plugin to integrate with user-mode QEMU.

* Anrew Kaylor posted an RFC proposing to [eliminate non-IR floating-point
  controls in the

SelectionDAG](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153460.html).
  'As a general principle, I would say, "All semantics must be
represented in
  the IR and the backend must respect the IR semantics." And a corollary:
  "Anything which can be represented at the instruction level must be
  represented at the instruction level." This corollary would eliminate
  potential conflicts between function attributes (like
"unsafe-fp-math") and
  individual IR instructions.' Respondents so far are in favour.

* Teresa Johnson [shared an
  RFC](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153435.html)
  introducing an IR metadata format for the sanitizer-based heap profiler
  (MemProf) when it is fed back into a subsequent compile for profile guided
  heap optimisation.

* LLVM GPU News #22 [is
  out](https://lists.llvm.org/pipermail/llvm-dev/2021-October/153500.html).


## LLVM commits

* Debug info location tracking was improved for the case where instructions
  have stack spills fused into them.
  [ee3eee7](https://reviews.llvm.org/rGee3eee71e415).

* The number of RISC-V vector builtins was reduced from ~25000 to ~1100 by
  sharing bultins for many different types.
  [e2b7aab](https://reviews.llvm.org/rGe2b7aabb57d5).

* Support was added for the AArch64 'R' architecture profile.
  [8689f5e](https://reviews.llvm.org/rG8689f5e6e773).

* A script for building release documentation was committed.
  [622346c](https://reviews.llvm.org/rG622346c60467).

* DeadStoreElimination learned to eliminate redundant stores of an existing
  value. [f87e0c6](https://reviews.llvm.org/rGf87e0c68d786).

* Guidance for buildbot owners was clarified.
  [a70a563](https://reviews.llvm.org/rGa70a5636a8a4).


## Clang commits

* A std::string checker was started as part of the Clang Static Analyzer.
  [e1fdec8](https://reviews.llvm.org/rGe1fdec875ff1).

* Clang vector builtins were documented, and some implementations committed.
  [025988d](https://reviews.llvm.org/rG025988ded6b2),
  [025988d](https://reviews.llvm.org/rG025988ded6b2).

* git-clang-format gained a --staged/--cached option.
  [bee61aa](https://reviews.llvm.org/rGbee61aa7b638).


## Other project commits

* The [automemcpy framework for automatic generation of fundamental memory
  operations](https://research.google/pubs/pub50338/) was added to LLVM's
  libc project. [00c943a](https://reviews.llvm.org/rG00c943a54885).

* The base of flang's FIR to LLVM IR MLIR dialect conversion pass was
  committed. [044d5b5](https://reviews.llvm.org/rG044d5b5dd184).

* LLDB's statistics dump command now reports the time it takes to parse and
  index the symbol tables for each module.
  [c571988](https://reviews.llvm.org/rGc571988e9d57).

* MLIR interfaces were exposed through the Python bindings.
  [14c9207](https://reviews.llvm.org/rG14c9207063bb).

* Support was added for Bazel builds on Windows with clang-cl.
  [112dc16](https://reviews.llvm.org/rG112dc16014f1).