[llvm-dev] LLVM Weekly - #280, May 13th 2019

[Alex Bradbury via llvm-dev]

LLVM Weekly - #280, May 13th 2019
=================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/280>.

Welcome to the two hundred and eightieth 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 next LLVM Developers' Meeting is
[scheduled](https://twitter.com/llvmorg/status/1127938834069508097) for
October 22-23rd in San Jose.

An LLVM Social will [take place in
Chicago](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132227.html) at a
yet-to-be determined date. Use the linked Doodle poll or meetup page to
indicate your preference.

GDB 8.3 [has been
released](https://sourceware.org/ml/gdb/2019-05/msg00018.html).


## On the mailing lists

* Alexey Sidorin [provides an
update](http://lists.llvm.org/pipermail/cfe-dev/2019-May/062285.html) on
support for a matcher-like checker API.

* Praveen Velliengiri is a GSoC student working on speculative compilation in
ORC, and introduces themselves
[here](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132348.html). Seiya
Nuta [will be working on improving LLVM binary
utilities](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132347.html).

* Paul Robinson
[suggests](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132298.html) the
removal of `REQUIRES: no*` instances in LLVM codebases as they may mislead
peope into thinking the `no*` prefix is understood by lit, and these cases can
be better handled using `UNSUPPORTED: `.

* Simon Pilgrim is [seeking
feedback](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132196.html) on
the current scan-build reports on LLVM and interest in fixing the reported
issues. Artem Dergacehv
[indicates](http://lists.llvm.org/pipermail/llvm-dev/2019-May/132269.html) a
GSoC project will be looking at static analyzer false positives.


## LLVM commits

* LoopSimplify learned to preserve MemorySSA.
[r360270](https://reviews.llvm.org/rL360270).

* Support was added for `AVX512_BF16` instructions, supported by the upcoming
Cooper Lake microarchitecture. [r360017](https://reviews.llvm.org/rL360017).

* On the ARM backend, register copies are now glued to tail calls. As
described in the commit message, the previous logic wasn't quite correct. If
your out-of-tree backend copied ARM you may want to review.
[r360099](https://reviews.llvm.org/rL360099).

* InstPrinter was moved to MCTargetDesc for various backends for consistency
with backends where this is necessary in order to avoid a circular dependency.
[r360484](https://reviews.llvm.org/rL360484),
[r360485](https://reviews.llvm.org/rL360485),
[r360486](https://reviews.llvm.org/rL360486),
[r360487](https://reviews.llvm.org/rL360487),
[r360488](https://reviews.llvm.org/rL360488), and more.


## Clang commits

* P1009R2 from C++20 was implemented, allowing the array bound in an array new
expression to be omitted. [r360006](https://reviews.llvm.org/rL360006).

* C++20 explicit(bool) support was committed.
[r360311](https://reviews.llvm.org/rL360311).

* The `-gz` and `-wA,--compress-debug-sections` options were updated to use
gABI compression rather than zlib-gnu.
[r360403](https://reviews.llvm.org/rL360403).

* clangd gained an intermediate representation of formatted text.
[r360151](https://reviews.llvm.org/rL360151).


## Other project commits

* The standalone version of the scudo allocator gained a Quarantine
implementation to hold chunks of memory prior to releasing them for potential
reuse. [r360163](https://reviews.llvm.org/rL360163).

* The LLDB python reference page was ported over from the old LLDB website.
[r360386](https://reviews.llvm.org/rL360386).