llvm dev - May 2018 - LLVM Weekly - #227, May 7th 2018

LLVM Weekly - #227, May 7th 2018
===============================
If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/227>.

Welcome to the two hundred and twenty-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 have
[started to
appear](https://www.youtube.com/playlist?list=PL_R5A0lGi1AB3cJDXMAbl4qCq94QxEcSA)
from EuroLLVM 2018.

The first London LLVM Social has been
[announced](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122937.html) for
Thursday May 17th. Be sure to RSVP if you're attending.

Glow, an optimizing compiler for neural networks [has been
released](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122987.html). It
builds upon LLVM technologies and is described in more detail [in this
paper](https://arxiv.org/pdf/1805.00907.pdf).

LLVM 5.0.2-final has [been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122956.html).


## On the mailing lists

* Richard Sandiford has posted an RFC on [adding variable-length
register-sized vector types to C and
C++](http://lists.llvm.org/pipermail/cfe-dev/2018-May/057830.html). Arm's
Scalable Vector Extension is the motivating use case.

* Rafael Avila de Espindola has announced that he is [leaving the LLLVM
project](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122922.html),
citing unhappiness with changes in the community: specifically the adoption of
a code of conduct and involvement with Outreachy. A range of LLVM developers
expressed sadness about this decision, and paid tribute to Rafael's
contributions.

* Dean Michael Berris
[shares](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122941.html) the
current plans for Sydney developers/users meetups. The plan is to start
regular workshop/study-group meetups, and to aim for a 1-day event in October.

* Welcome to Mikhail Ramalho who will be working with the Clang static
analyzer and Z3 SMT solver [as part of Google Summer of
Code](http://lists.llvm.org/pipermail/cfe-dev/2018-May/057831.html).

* Alexandros Lamprineas wonders about [best practice for using auto-generated
test
assertions](http://lists.llvm.org/pipermail/llvm-dev/2018-May/122996.html),
such as those generated by `update_llc_test_checks.py`.

* Walter Lee has [ported ASan to Myriad
RTEMS](http://lists.llvm.org/pipermail/llvm-dev/2018-May/123018.html), has
shared a [design
document](https://docs.google.com/document/d/1oxmk0xUojybDaQDAuTEVpHVMi5xQX74cJPyMJbaSaRM)
and is seeking feedback on the patch series.


## LLVM commits

* The SystemZ backend no longer users glue to represent condition code
dependencies and instead represents them as normal values during SelectionDAG
matching. [r331202](https://reviews.llvm.org/rL331202).

* The GlobalISel emitter has been updated to reflect the new representation of
extending loads. [r331601](https://reviews.llvm.org/rL331601).

* llvm-mca gained a test that demonstrates support for generating instruction
tables for in-order CPUs. [r331169](https://reviews.llvm.org/rL331169).


## Clang commits

* Initial support was added for the proposed `char8_t` type. This is
controlled by the flag `-fchar8_t` and is subject to change.
[r331244](https://reviews.llvm.org/rL331244).

* The MachineOutliner can now be explicitly enabled for AArch64 using
`-foutline`. [r331370](https://reviews.llvm.org/rL331370).

* getConstraintRegister was implemented for ARM and AArch64, allowing an error
to be generated if there are conflicts between the clobber list and
input/output lists for inline assembly.
[r331164](https://reviews.llvm.org/rL331164).


## Other project commits

* The WebAssembly linker now supports DWARF sections.
[r331566](https://reviews.llvm.org/rL331566).

* LLD gained support for the ThinLTO plugin options thinlto-index-only and
thinlto-prefix-replace. [r331405](https://reviews.llvm.org/rL331405).

* Code comments in LLDB have been reflowed, as the previous clang-formatting
of the codebase left some paragraphs in a hard to read state.
[r331197](https://reviews.llvm.org/rL331197).