llvm dev - Apr 2018 - LLVM Weekly - #226, Apr 30th 2018

LLVM Weekly - #226, Apr 30th 2018
================================
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<http://llvmweekly.org/issue/226>.

Welcome to the two hundred and twenty-sixth 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.

For those of you attending the Barcelona RISC-V Workshop May 7th-10th, be sure
to come along to [my short tutorial session on RISC-V
LLVM](https://riscv.org/2018/04/risc-v-workshop-in-barcelona-agenda/).


## News and articles from around the web

LLVM 6.0.1-rc1 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122776.html).

Simon Brand has written a fantastic introductory blog post on [custom alias
analysis in LLVM](https://blog.tartanllama.xyz/llvm-alias-analysis/).


## On the mailing lists

* Simon Tatham is interested in contributing a [JSON backend for
TableGen](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122723.html),
providing a machine-readable alternative to -print-records. An initial patch
is already [up for review](https://reviews.llvm.org/D46054).

* Following on from his lightning talk at EuroLLVM, Kristof Beyls has shared a
[script for matching up open Phabricator reviews to potential
reviewers](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122817.html)
and is seeking feedback.

* The Google Summer of Code community bonding period is starting up. Welcome
to [Alexander
Polyakov](http://lists.llvm.org/pipermail/lldb-dev/2018-April/013593.html) who
will be working on LLDB-mi and to [Anastasis
Grammenos](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122760.html)
who will be working on improving debugging of optimized code.

* Jin Lin has an RFC on [representing target device information in LLVM
IR](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122767.html), which is
needed for OpenMP backend outlining.

* George Rimar reports back on [current code coverage of the LLD (ELF)
tests](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122782.html).

* Danil Malyshev has been looking at the impact type-based alias analysis
(TBAA) on the LLVM test suite and [reports
results](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122804.html).

* Ciro Ceissler shares news of the [HardCloud OpenMP
extension](http://lists.llvm.org/pipermail/llvm-dev/2018-April/122810.html)
for offloading to FPGA accelerators.


## LLVM commits

* GlobalISel now has dedicated extended loads.
[r331115](https://reviews.llvm.org/rL331115).

* A new AArch64 DAG combine will fold offsets into addresses in the case where
all users of the global address are of the form globaladdr + constant.
[r330630](https://reviews.llvm.org/rL330630).

* The new CFIInserter pass is used to ensure correct dwarf unwind information
is emitted in the function epilogue. It is currently x86-only.
[r330706](https://reviews.llvm.org/rL330706).

* The 'call' pseudoinstruction is now supported by the RISC-V MC layer.
[r330826](https://reviews.llvm.org/rL330826).

* The MIPS backend gained support for the Virtualizations Application Specific
Extension. [r331024](https://reviews.llvm.org/rL331024).


## Clang commits

* The `-Qn` option can be used to suppress the emission of llvm.ident compiler
version metadata. [r330575](https://reviews.llvm.org/rL330575).

* Clang gained a new warning for atomic accesses using libcalls (access to
misaligned locations or large values).
[r330566](https://reviews.llvm.org/rL330566).

* Clangd now supports workspace/symbol requests.
[r330637](https://reviews.llvm.org/rL330637).


## Other project commits

* An arena allocator was added to compiler-rt for use by XRay Profiling Mode.
[r331141](https://reviews.llvm.org/rL331141).

* libcxx gained an `<experimental/simd>` implementation.
[r330655](https://reviews.llvm.org/rL330655).