[llvm-dev] LLVM Weekly - #164, Feb 20th 2017
Alex Bradbury via llvm-dev
llvm-dev at lists.llvm.org
Mon Feb 20 11:21:19 PST 2017
LLVM Weekly - #164, Feb 20th 2017
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Welcome to the one hundred and sixty-fourth 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
Sources and binaries for LLVM 4.0.0-rc2 are [now
The next LLVM social in Berlin [will be held on February
The next LLVM social in Belgium [will be held on the 6th of
The NetBSD Foundation has a new blog post summarising
[recent changes to LLDB for NetBSD
Manu Sánchez has blogged about [writing AST matchers for
Version 5 of the DWARF debugging standard [has been
## On the mailing lists
* Would you be interested in an LLVM social [in
so, speak up!
* Quentin Colombet has [clarified the plan for moving forwards with
* Ayalk Zaks and Gil Rapaport are [seeking
on 'VPlan', a model for vectorisation that hopes to capture all vectorisation
decisions. A PDF detailing VPlan is [available
* Zachary Turner has written up on RFC on [adding a new stream abstraction to
proposed ThinStream gives a read-only API that encourages zero-copy access,
while WritableThinStream allows writing. There are also variants that allow
reading and writing of semantic data rather than raw bytes.
* Mehdi Amini [kicked off
on what sort of criteria LLVM should use to rank proposed student projects.
* Steven Perron has written an RFC on [representing unions in
* Witold Waligora has proposed [JumpMaps, a variant/generalisation of
* Martell Malone has proposed a [new dlltool replacement for
is looking for feedback.
* Alex Bradbury has written an [RFC about setting FrameSetup/FrameDestroy
when spilling or restoring callee-saved registers. We'd really welcome further
feedback from debuginfo experts.
## LLVM commits
* Support for "debug counters" was added. This is a tool to help narrow down
miscompilation to a particular transformation from the command-line.
* The default threshold for full loop unrolling has been increased for the O3
optimisation level, meaning more loops will be unrolled.
* Documentation on LLVM's type-based alias analysis metadata has seen a
sizable update. [r294999](http://reviews.llvm.org/rL294999).
* Tablegen DAGGenISelDAG gained a new feature to aid debugging instruction
* MachineBlockPlacement learnt to better layout trellis-shaped CFGs.
* Support for the Cavium ThunderX ARM64 processors (including a scheduler) was
## Clang commits
* The number of UBSan-inserted null checks on C++ object pointers has been
significantly reduced. [r295391](http://reviews.llvm.org/rL295391).
* Clang's code completion now recognises the previously missing C++11
* C++1z class template argument deduction is now considered 'done'.
* The new readability-misleading-indentation checker will warn if indentation
around unbraced if/else statements may be misleading (and likely indicate
programmer error). [r295041](http://reviews.llvm.org/rL295041).
## Other project commits
* XRay is now supported on the MIPS targets.
* The LLDB Utility library is now standalone, without dependencies on other
parts of LLDB. [r295368](http://reviews.llvm.org/rL295368).
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