llvm dev - Dec 2019 - LLVM Weekly - #313, December 30th 2019

LLVM Weekly - #313, December 30th 2019
=====================================
If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/313>.

Welcome to the three hundred and thirteenth 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

I didn't spot any relevant news or articles in the past week, presumably
everyone is busy enjoying the break. However it's worth highlighting the
import of [MLIR](https://mlir.llvm.org/) into the LLVM tree.


## On the mailing lists

* Anton Korobeynikov is [seeking project proposals for LLVM in GSoC
2020](http://lists.llvm.org/pipermail/llvm-dev/2019-December/137809.html). As
explained in full detail in the message, proposed projects should aim to
contribute directly to LLVM or its subprojects rather than to a downstream /
3rd-party project that uses LLVM.

* Brian Gesiak shares an RFC on [new work to port coroutines passes to the new
pass
manager](http://lists.llvm.org/pipermail/llvm-dev/2019-December/137835.html).
Brian has posted 6 patches as part of this effort and is seeking further
reviewers and feedback. These patches don't yet support Swift's
"returned-continuation" or the "devirtualization trigger".

* Siva Chandra
[proposes](http://lists.llvm.org/pipermail/libc-dev/2019-December/000030.html)
moving LLVM's libc over to using a top-level test directory like other LLVM
subprojects, in order to avoid issues encountered with CMake.

* David Blaikie returns to the thread he started on `DW_OP_implicit_pointer`
in LLVM to [propose a path
forwards](http://lists.llvm.org/pipermail/llvm-dev/2019-December/137827.html),
implementing `OP_LLVM_explicit_pointer` as a more general feature.


## LLVM commits

* LowerMatrixIntrinsics gained forward shape propagation and some initial
shape-aware lowerings. [109e4e3](https://reviews.llvm.org/rG109e4e3851e).

* As part of the attributor work, a new function-level undefined behaviour
attribute was added. [58f324a](https://reviews.llvm.org/rG58f324a468f).

* The runtime of the `find_interesting_reviews.py` script was reduced by the
introduction of a git blame output cache.
[5bd9eee](https://reviews.llvm.org/rG5bd9eee53d1).

* no-frame-pointer-elim, no-frame-pointer-elim-non-leaf, and
no-frame-pointer-elim=false attributes were migrated to `frame-pointer={all,
non-leaf, none}`. [502a77f](https://reviews.llvm.org/rG502a77f125f),
[eb16435](https://reviews.llvm.org/rGeb16435b5e5),
[a36ddf0](https://reviews.llvm.org/rGa36ddf0aa9d).

* pragma omp parallel code generation was added to the OpenMP IR Builder in
the Frontend library. [e4add972](https://reviews.llvm.org/rGe4add9727b4).


## Clang commits

* OpenMP 5.0 support continues to develop with the addition of basic support
for conditional lastprivate and codegen for the nontemporal clause.
[93dc40d](https://reviews.llvm.org/rG93dc40dddde),
[0860db9](https://reviews.llvm.org/rG0860db966a7).

* The clang-tidy docs now shows the supported checkers in tables rather than a
large list. [d2c9c91](https://reviews.llvm.org/rGd2c9c9157b0).


## Other project commits

* MLIR was imported into the LLVM tree. See
[mlir.llvm.org](https://mlir.llvm.org/) for more info.
[0f0d0ed](https://reviews.llvm.org/rG0f0d0ed1c78).

* LLVM's libc gained implementations of POSIX mmap and munmap functions.
[e5a743c](https://reviews.llvm.org/rGe5a743c4f6e).