[llvm-dev] LLVM Weekly - #303, October 21st 2019

[Alex Bradbury via llvm-dev]

LLVM Weekly - #303, October 21st 2019
=====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/303>.

Welcome to the three 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.

I'll be at the LLVM Dev Meeting this week - I look forward to seeing many of
you there! I'm giving a talk on lessons learned from the RISC-V backend on
Tuesday.


## News and articles from around the web

Version 1.4 of the of the pocl OpenCL implementation [was
released](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135892.html),
as was [v1.20 of the TTA-based Co-Design
Environment](http://lists.llvm.org/pipermail/llvm-dev/2019-October/136012.html).
In both cases, support was added for LLVM 9.0.


## On the mailing lists

* Tom Stellard is seeking feedback on [when committing with git-llvm should
become
optional](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135912.html).
The primary motivation of the git-llvm wrapper script was to enforce a linear
commit history. GitHub now supports a branch protection rule for this. Most
respondents are in favour of retiring the git-llvm script as soon as possible.

* DeForest Richards is looked for [feedback on LLVM docs updates done through
the Google Season of
Docs](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135920.html).

* Stephen Kelly gave a [detailed update on AST
matcher](http://lists.llvm.org/pipermail/cfe-dev/2019-October/063667.html).
The post also discusses current policy on use of `auto` in the LLVM codebase.

* Galina Kistanova shares details on [Zorg migration for the GitHub
monorepo](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135910.html).
If you run a bot, do check to see if it may be affected.

* Sriraman Tallam has [summarised all the concerns raised about merging
Propeller](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135900.html).

* Simon Moll is [seeking
reviewers](http://lists.llvm.org/pipermail/llvm-dev/2019-October/136041.html)
for initial patches for the NEC SX-Aurora Vector Engine.

* Alina Sbirlea gives a [heads up on patches to delete
BasicBlockPass/BasicBlockManager](http://lists.llvm.org/pipermail/llvm-dev/2019-October/136021.html).

* Nicolai Hähnle-Montoro suggests [redefining 'convergent' in terms of dynamic
instances](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135929.html).

* Tom Stellard flags that [SVN commit emails will be replaced with git commit
emails
week](http://lists.llvm.org/pipermail/llvm-dev/2019-October/135943.html).


## LLVM commits

* AArch64 now supports stackframe access to SVE objects.
[r374772](https://reviews.llvm.org/rL374772).

* A new pass was introduced to lower `is.constant` and `objectisze`
intrinsics, replacing the previous lowering in the codegen-prepare pass and
instruction selection fallbacks. [r374743](https://reviews.llvm.org/rL374743).

* The RISC-V backend now supports the fastcc calling convention.
[r374857](https://reviews.llvm.org/rL374857).

* The RISC-V backend now performs immediate verification in the
`TargetInstrInvo::verifyInstruction` hook.
[r375006](https://reviews.llvm.org/rL375006).

* Some initial infrastructural changes were merged for profile-guided size
optimisations. [r375254](https://reviews.llvm.org/rL375254).


## Clang commits

* As part of the C++20 concepts implementation effort, support for Concept
Specialization Expressions and associated constraints was added.
[r374882](https://reviews.llvm.org/rL374882),
[r374938](https://reviews.llvm.org/rL374938).

* Clang's C++20 support was extended to allow rewriting from comparison
operators to `<=>` / `==`. [r375306](https://reviews.llvm.org/rL375306).

* Clang now supports the OpenMP 5.0 'parallel master taskloop' construct.
[r374791](https://reviews.llvm.org/rL374791).

* Clang learned the `-Wa,-W` option to suppress warning messages in the GNU
assembler. [r374822](https://reviews.llvm.org/rL374822).

* Documentation was written describing the current level of OpenCL support.
[r375111](https://reviews.llvm.org/rL375111).


## Other project commits

* LLD's COFF linker learned to report source locations for duplicate symbols.
[r375218](https://reviews.llvm.org/rL375218).

* Some initial ARC support landed in LLDB.
[r375122](https://reviews.llvm.org/rL375122),
[r375123](https://reviews.llvm.org/rL375123).