[llvm-dev] LLVM Weekly - #357, November 2nd 2020

[Alex Bradbury via llvm-dev]

LLVM Weekly - #357, November 2nd 2020
=====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/357>.

Welcome to the three hundred and fifty-seventh 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

Videos from the 2020 LLVM Virtual Developers' Meeting have started to be
posted
[on YouTube](https://www.youtube.com/playlist?list=PL_R5A0lGi1ABzH_FIZSx0sHQkOqI7p4Cg).


## On the mailing lists

* Geoffrey Martin-Noble proposes [contributing Bazel BUILD files for
LLVM](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146138.html),
suggesting they be maintained with a similar support level to the in-tree gn
build system. This triggered a lengthy discussion, which inspired Renato Golin
to create a new thread to discuss a more general [policy on "support
tiers"](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146249.html).

* The nineteenth issue of the MLIR newsletter is [out
now](https://llvm.discourse.group/t/mlir-news-19th-edition-10-31-2020/2036),
including info on sparse code generation work, Python bindings, and more.

* Anna Sophia Welker is considering a Master thesis topic related to VPlan and
[seeking input on goals for VPlan-based cost
modelling](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146236.html).

* Mircea Trofin shared an RFC on [disallowing unused prefixes in
FileCheck](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146162.html).

* Gulfem Savrun Yeniceri suggests [adding leaf attribute support to
Clang/LLVM](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146113.html),
outlining a high level design and sharing an initial patch.

* Reshabh Kumar Sharma shared a proposal to [implement the sanitizer runtimes
for heterogeneous
devices](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146159.html).

* Anton Korebeynikov [notes some changes to the Google Summer of Code 2021
program](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146233.html),
and asks potential mentors start thinking about potential projects with these
changes in mind.

* Nicolai Hähnle [restarted discussions on his RFC thread about introducing
convergence control bundles and
intrinsics](http://lists.llvm.org/pipermail/llvm-dev/2020-October/146137.html).


## LLVM commits

* The patches introducing the CfgTraits abstraction were reverted pending more
discussion. [e025d09](https://reviews.llvm.org/rGe025d09b216).

* A new per-basic-block optimisation remark was added, summarising the count
for each machine opcode. [b2bec7cec](https://reviews.llvm.org/rGb2bec7cece9).

* Support was added for POWER10 set boolean condition instructions.
[803cc3a](https://reviews.llvm.org/rG803cc3aff2c).

* Implementation of the VE backend continues with support for many more vector
instructions. [c5fa6ba](https://reviews.llvm.org/rGc5fa6bae12f),
[83cb423](https://reviews.llvm.org/rG83cb423c6e1),
[9d0db40](https://reviews.llvm.org/rG9d0db405b57), and many more.

* An AMDGPU late codegen preparation pass was added.
[46c3d5c](https://reviews.llvm.org/rG46c3d5cb05d).

* Documentation on special treatment of PHIs in loop analyses was added.
[a334530](https://reviews.llvm.org/rGa3345300b6f).


## Clang commits

* Driver commandline remarks options will now be passed to the linker when LTO
is enabled, making it easier to collect remarks from both pre-LTO and LTO
compilation. [c486870](https://reviews.llvm.org/rGc4868700c58).

* `[[likely]]` and `[[unlikely]]` attributes can now be used on while and for
loops. [b46fddf](https://reviews.llvm.org/rGb46fddf75fc).

* `__vector_pair` and `__vector_quad` types were added for PowerPC.
[40dd4d5](https://reviews.llvm.org/rG40dd4d5233d).

* Various changes were made to the FileEntryRef API.
[84e8257](https://reviews.llvm.org/rG84e8257937e).


## Other project commits

* A libc++ configuration that doesn't support localisation was introduced,
meant for e.g. embedded systems.
[88ffc72](https://reviews.llvm.org/rG88ffc72717c).

* Watchpoint support was enabled for LLDB on FreeBSD.
[8e7ea99](https://reviews.llvm.org/rG8e7ea99c382).

* An mlir-spirv-cpu-runner prototype was added, intended to run a GPU kernel
on a CPU via GPU to SPIRV to LLVM conversions.
[89808ce](https://reviews.llvm.org/rG89808ce7343).