[llvm-dev] LLVM Weekly - #274, April 1st 2019

[Alex Bradbury via llvm-dev]

LLVM Weekly - #274, April 1st 2019
==================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/274>.

Welcome to the two hundred and seventy-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](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

LLVM is taking part of Google Summer of Code this year. Students, see [the
open projects list](https://llvm.org/OpenProjects.html#gsoc19) for ideas.

The LLVM blog has
[information](http://blog.llvm.org/2019/03/llvm-numerics-blog.html) useful as
preparation for the numeric birds of a feather session at EuroLLVM.

LLVM 7.1.0-rc1 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2019-March/131375.html).


## On the mailing lists

* Eric Christopher shared a
[proposal](http://lists.llvm.org/pipermail/llvm-dev/2019-March/131411.html)
for revamping the `-O1` and `-Og` optimisation levels, generating plenty of
discussion.

* More discussion on scalable vector types in LLVM IR took place this week.
See comments from [Sebastian
Pop](http://lists.llvm.org/pipermail/llvm-dev/2019-March/131376.html) and [Hal
Finkel](http://lists.llvm.org/pipermail/llvm-dev/2019-March/131377.html).

* Javed Absar has [posted an
RFC](http://lists.llvm.org/pipermail/llvm-dev/2019-March/131358.html) on
upstreaming Clang+LLVM support for ARMv8-M security extensions.


## LLVM commits

* The WebAssembly backend gained an initial implementation of PIC code
generation. [r357022](https://reviews.llvm.org/rL357022).

* A summary of the discussion around changing the LLVM variable naming scheme
was committed. [r357174](https://reviews.llvm.org/rL357174).

* The LLVM side of codegen support for the RISC-V hard float ABIs was
committed. A Clang patch will follow.
[r357352](https://reviews.llvm.org/rL357352).

* The SMT solver API SMTAPI was moved from Clang up to LLVM.
[r356929](https://reviews.llvm.org/rL356929).

* Range checks will now be emitted for jump tables created from switches with
an unreachable default. [r357067](https://reviews.llvm.org/rL357067).

* An analysis invalidation bug in the new pass manager was fixed, and as usual
is associated with a detailed commit message.
[r357137](https://reviews.llvm.org/rL357137).

* An experimental MicroOpQueue stage was modeled in llvm-mca.
[r357248](https://reviews.llvm.org/rL357248).


## Clang commits

* Clang learned a new `-ftime-trace` option, that produces chrome://tracing
compatible JSON profiling output.
[r357340](https://reviews.llvm.org/rL357340).

* Further improvements were made to creduce-clang-crash.py.
[r357290](https://reviews.llvm.org/rL357290).


## Other project commits

* Kalimba platform support was removed from LLDB.
[r357086](https://reviews.llvm.org/rL357086).

* Range extension thunk insertion was optimised for the COFF LLD linker.
[r357200](https://reviews.llvm.org/rL357200).