[llvm-dev] LLVM Weekly - #349, September 7th 2020

[Alex Bradbury via llvm-dev]

LLVM Weekly - #349, September 7th 2020
======================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/349>.

Welcome to the three hundred and forty-ninth 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

C++20 [has been
approved](https://herbsutter.com/2020/09/06/c20-approved-c23-meetings-and-schedule-update/).


## On the mailing lists

* Andrew Litteken posted an RFC on [a framework for defining, detecting, and
deduplicating similar code sections at the IR
level](http://lists.llvm.org/pipermail/llvm-dev/2020-September/144779.html).
The RFC presents results for an IR outliner implemented on top of this
framework.

* Djordje Todorovic posted an RFC on [using `DW_OP_entry_value` within LLVM
IR](http://lists.llvm.org/pipermail/llvm-dev/2020-September/144728.html).

* Petr Hosek is seeking advice on [adding a HTTP library to
LLVM](http://lists.llvm.org/pipermail/llvm-dev/2020-August/144708.html). The
use case is to provide an implementation of debuginfod.

* Atmn Patel posted an RFC on [introducing a maynotprogress IR
attribute](http://lists.llvm.org/pipermail/llvm-dev/2020-September/144865.html).
Johannes Doerfert followed up with [further explanation of the issues with
llvm.sideefffect](http://lists.llvm.org/pipermail/llvm-dev/2020-September/144872.html).

* Lang Hames sent a heads-up that he [intends to remove OrcV1 some point after
the 14th of
September](http://lists.llvm.org/pipermail/llvm-dev/2020-September/144885.html),
inviting any questions.

* Thomas Lively thread about [inlining with different target
features](http://lists.llvm.org/pipermail/llvm-dev/2020-August/144399.html)
generated further discussion this week.


## LLVM commits

* Experimental MachineInstr stable hashing has been committed, bringing stable
hashing to MIRVRegNamer and MIRCanonicalizer.
[7fff1fb](https://reviews.llvm.org/rG7fff1fbd3ce).

* The FileCheck implementation has been moved out of LLVMSupport and into its
own library. [e9a3d1a](https://reviews.llvm.org/rGe9a3d1a401b).

* An initial canReplacePointersIfEqual helper was written.
[0d966ae](https://reviews.llvm.org/rG0d966ae4b2a).

* `-lint` has been ported to the new pass manager.
[c977139](https://reviews.llvm.org/rGc9771391ce0).


## Clang commits

* A partial implementation of `#pragma STDC FENV_ROUND` was committed.
[a633da5](https://reviews.llvm.org/rGa633da5391b).

* New readability-prefer-member-initializer and
bugprone-redundant-branch-condition checks were added to clang-tidy.
[f5fd748](https://reviews.llvm.org/rGf5fd7486d6c),
[14dd073](https://reviews.llvm.org/rG14dd0737822).

* The initial toolchain driver was added for z/OS.
[3e1e5f5](https://reviews.llvm.org/rG3e1e5f54492).

* CXRewriter was added to the libclang API.
[69e5abb](https://reviews.llvm.org/rG69e5abb57b7).


## Other project commits

* Type constraints were introduced for operands of MLIR's LLVM dialect
operations. [aec9e20](https://reviews.llvm.org/rGaec9e20a3e9).

* libFuzzer gained an option to keep initial seed inputs.
[62673c4](https://reviews.llvm.org/rG62673c430de).

* libFuzzer will now scale the energy assigned to each input based on the
input execution time. [5cda4dc](https://reviews.llvm.org/rG5cda4dc7b4d).

* Implementations of remquo[f|l] and remainder[f|l] were added to LLVM's libc.
[8514ecb](https://reviews.llvm.org/rG8514ecb02d4).

* A reproducer verifier was added to LLDB, checking for e.g. a missing o
invalid working directory. [3746906](https://reviews.llvm.org/rG3746906193c).