[llvm-dev] LLVM Weekly - #113, Feb 29th 2016
Alex Bradbury via llvm-dev
llvm-dev at lists.llvm.org
Mon Feb 29 06:55:45 PST 2016
LLVM Weekly - #113, Feb 29th 2016
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Welcome to the one 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](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
LLVM and Clang 3.8RC3 [has been
EuroLLVM 2016 is [less than a month
you want to attend, be sure to
The Red Hat blog has a [summary of new features in the upcoming GCC 6
The Meeting C++ blog has a [helpful summary of a subset of the proposals for
the next C++ committee
## On the mailing lists
* Chandler Carruth has suggested [moving the LLVM test-suite repository to
In response to some concerns, Chris Lattner points out that using GitHub in
this case [doesn't mean abandoning the current development
it just means it can be augmented with GitHub-style pull requests for those
who prefer it. Chandler [summarised the
and provided a list of next steps.
* Sanjoy Das [pointed out a potential soundness issue with the
This triggered a very long discussion. James Knight pointed out the same issue
[could happen with normal functions in a shared
There was some back and forth between Hal Finkel and Chandler Carruth [on the
best approach to addressing this
* Philip Reames asks whether [a PHI depending on another PHI in the same basic
It's currently accepted by the verifier but arguably shouldn't be. So far,
nobody has argued that it should be valid.
* Matthias Braun kicked off a discussion on [better defining the semantics of
reserved and unallocatable
After more discussion, he followed up with a [revised
* David Li has posted a [proposal for supporting in-process merging of profile
## LLVM commits
* The Sparc backend now contains definitions for all registers and
instructions defined in the Sparc v8 manual.
* LLVM gained a basic LoopPassManager, though it currently only contains dummy
* A number of TargetInstrInfo predicates now take a reference to a
MachineInstr rather than a pointer.
* The WebAssembly backend gained redzone support for the userspace stack.
## Clang commits
* Whole-program vtable optimisation is now available in Clang using the
`-fwhole-program-vtables` flag. [r261767](http://reviews.llvm.org/rL261767).
* Clang gained `__builtin_canonicalize` which returns the platform-specific
canonical encoding of a floating point number.
* A hasAnyName matcher was added. [r261574](http://reviews.llvm.org/rL261574).
* The pointer arithmetic checker has been improved to report fewer false
## Other project commits
* The new ELF linker gained support for identical code folding (ICF). This
reduces the size of an LLD binary by 3.6% and of a Clang binary by 2.7%. As
described in the commit message, this is not a "safe" version of ICF as
implemented in GNU gold, so will cause issues if the input relies on two
distinct functions always having distinct addresses.
* Polly's tree now contains an `update_check.py` script that may be useful to
other LLVM devs. It updates a FileCheck-based lit test by updating the
`CHECK:` lines with the actual output of the `RUN:` command.
* LLDB gained a new set of plugins to help debug Java programs, specifically
Java code JIT-ed by the Android runtime.
* The new OpenMP 4.5 affinity API is now supported in LLVM's openmp
* The new ELF linker gained support for the `-r` command-line option, which
produces relocatable output (partial linking).
* The CMake/lit runner for SPEC in the LLVM test-suite can now run the C
CPU2006 floating point benchmarks (but not the Fortran ones).
* The old ELF linker has been deleted from LLD.
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