[llvm-dev] LLVM Weekly - #161, Jan 30th 2017

Alex Bradbury via llvm-dev llvm-dev at lists.llvm.org
Mon Jan 30 07:12:53 PST 2017

LLVM Weekly - #161, Jan 30th 2017

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Welcome to the one hundred and sixty-first 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](http://asbradbury.org). 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

Microsoft have
a new open source DirectX shader compiler based on Clang and LLVM.

LLVM 4.0.0-rc1 source and binaries are [now
Time to get testing!

## On the mailing lists

* Johannes Doerfert has posted an [RFC for adding parallel extensions to LLVM

* Chas Boyd has
to the mailing list to say a little more about Microsoft's use of LLVM and
Clang in the new DirectX Shader Compiler.

* Manuel Klimek reports that [work is starting on
ClangD](http://lists.llvm.org/pipermail/cfe-dev/2017-January/052458.html), a
daemon to provide access IDEs etc with access to Clang services.

* Philip Herron is curious about [selection of negative addition rather than
Matt Arsenault
how this behaviour can be overridden.

* Guy Blank has posted an RFC on [making i1 illegal in X86

## LLVM commits

* NewGVN gained support for dead and redundant store elimination.

* A new MemorySSA updater has been introduced.

* A new guard-based loop predication optimisation has been added. This will
enable more guards to be hoisted out of loops.

* lit has been expanded to allow boolean expressions in REQUIRES, XFAIL, and
UNSUPPORTED lines. [r292896](http://reviews.llvm.org/rL292896).

* Early if-conversion has been implemented for AMDGPU, but is disabled by
default for now. [r293016](http://reviews.llvm.org/rL293016).

* The llvm-xray graph subcommand now colors edges and vertices based on
statistics. [r293031](http://reviews.llvm.org/rL293031).

* A new OptimizationRemarkEmitter pass was added, allowing MIR passes to emit
optimisation remarks just like IR passes can.

* The MIPS backend gained support for the static relocation model with the N64
ABI. [r293279](http://reviews.llvm.org/rL293279).

* A number of new intrinsics for constrained floating point operations have
been added. [r293226](http://reviews.llvm.org/rL293226).

## Clang commits

* A new TableGen-based generator for command line argument documentation was
added. [r292968](http://reviews.llvm.org/rL292968).

* Comment reflowing has been implemented for clang-format.

## Other project commits

* XRay 'Flight Data Recorder' mode was implemented, which allows XRay to log
in-memory and then write out data on-demand as required.

* LLD learned to handle the MEMORY linkerscript command.

* LLDB now supports single stepping on ARM FreeBSD.

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