[llvm-dev] LLVM Weekly - #205, Dec 4th 2017

[Alex Bradbury via llvm-dev]

LLVM Weekly - #205, Dec 4th 2017
================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/205>.

Welcome to the two hundred and fifth 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.

If you weren't able to make it to the 7th RISC-V Workshop in Milpitas last
week, you might find my
[blog](http://www.lowrisc.org/blog/2017/11/seventh-risc-v-workshop-day-one/)
[summary](http://www.lowrisc.org/blog/2017/11/seventh-risc-v-workshop-day-two/)
on lowrisc.org useful.


## News and articles from around the web

LLVM/Clang 5.0.1-rc2 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2017-November/119383.html).

The call for papers has been
[issued](http://lists.llvm.org/pipermail/llvm-dev/2017-November/119411.html)
for the LLVM Performance Workshop at CGO 2018. This will take place on
February 24th in Vienna, Austria.


## On the mailing lists

* Alexey Kukanov has published an RFC on [contributing Intel's Parallel STL
implementation to
libc++](http://lists.llvm.org/pipermail/cfe-dev/2017-November/056135.html).

* Artem Dergachev has [started to
document](http://lists.llvm.org/pipermail/cfe-dev/2017-November/056095.html) a
number of issues preventing inlining in C++ code.

* Mohammed Agabaria
[proposes](http://lists.llvm.org/pipermail/llvm-dev/2017-November/119364.html)
adding a `no-overflow` keyword to the sdiv and udiv IR instructions.

* Greg Clayton has responded to a user question with a [handy summary of how
to remotely launch a new process in
LLDB](http://lists.llvm.org/pipermail/lldb-dev/2017-November/012979.html).

* Jonas Thiem is [looking for
answers](http://lists.llvm.org/pipermail/llvm-dev/2017-November/119269.html)
to a licensing question about the runtime libraries, and [further
elaborates](http://lists.llvm.org/pipermail/llvm-dev/2017-November/119334.html)
in this follow-up.


## LLVM commits

* A new SpeculateAroundPHIs pass has been introduced. It's stunningly well
documented, so well worth a ready.
[r319164](http://reviews.llvm.org/rL319164).

* The new `-stack-size-section` flag causes metadata to be emitted in an ELF
section with information on function stack sizes.
[r319430](http://reviews.llvm.org/rL319430).

* MergeConsecutiveStores is now run a second time, just before instruction
selection. This allows lowered intrinsics to be merged as well.
[r319036](http://reviews.llvm.org/rL319036).

* The MachineVerifier PHI and register operand checking has been improved.
[r319140](http://reviews.llvm.org/rL319140),
[r319141](http://reviews.llvm.org/rL319141).

* You can now use `-ppc-reg-with-percent-prefix` to get more readable PPC
assembler output. [r319381](http://reviews.llvm.org/rL319381).

* The ARC backend can now assemble a subset of ARC instructions.
[r319609](http://reviews.llvm.org/rL319609).


## Clang commits

* clang-format gained options to control sorting of include blocks, allowing
groups to be sorted individually, merged and sorted, and merged and resplit.
[r319024](http://reviews.llvm.org/rL319024).

* A number of math libcalls/builtins are now converted to equivalent LLVM
intrinsics. [r319593](http://reviews.llvm.org/rL319593).

* clangd gained a fuzzy match scorer.
[r319557](http://reviews.llvm.org/rL319557).


## Other project commits

* LLD gained support for range extension thunks on AArch64.
[r319307](http://reviews.llvm.org/rL319307).

* LLD has reduced the size of the .gnu.hash section.
[r319503](http://reviews.llvm.org/rL319503).

* LLDB remote debugging documentation has been updated.
[r319213](http://reviews.llvm.org/rL319213).


## Review corner

The LLVM Weekly review corner serves to highlight patches that are stuck
waiting awaiting review, or work from first-time contributors. See
[here](http://llvmweekly.org/reviewcorner) for more information and how to
submit you work for inclusion. Of course the hope is that highlighting these
patches will enable LLVM Weekly readers will step up and help to get them
merged. I'll be reporting back each week on any activity generated on these
patches, as well as sharing a new batch. If you want your patch included you
must submit it via the linked form.

After a quiet period, we've had some new patch submissions this week. Three
were submitted, though [D38778](https://reviews.llvm.org/D38778) (support for
the PowerPC Signal Processing Engine) has actually had reviews since being
submitted. Thanks Nemanja Ivanovic!

* "Allows pretty printing of declarations through the libclang (C) API. This
is useful for e.g. tooltips in an IDE - hover a function call and get the
corresponding declaration as tooltip."
[D39903](https://reviews.llvm.org/D39903), patch by Nikolai Kosjar.

* "This patch extends clang's -verify option to support prefixes similar to
FileCheck's --check-prefixes. While -verify plus preprocessor directives could
already accomplish the same goal, source is often easier to read/maintain
without preprocessor directives or duplicate passages of code (see updated
clang tests in patch)." [D39694](https://reviews.llvm.org/D39694), patch by
Joel E. Denny.