LLVM Weekly - #227, May 7th 2018

Welcome to the two hundred and twenty-seventh 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. Subscribe to future issues at https://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to asb@asbradbury.org, or @llvmweekly or @asbradbury on Twitter.

News and articles from around the web

Videos have started to appear from EuroLLVM 2018.

The first London LLVM Social has been announced for Thursday May 17th. Be sure to RSVP if you're attending.

Glow, an optimizing compiler for neural networks has been released. It builds upon LLVM technologies and is described in more detail in this paper.

LLVM 5.0.2-final has been tagged.

On the mailing lists

• Richard Sandiford has posted an RFC on adding variable-length register-sized vector types to C and C++. Arm's Scalable Vector Extension is the motivating use case.

• Rafael Avila de Espindola has announced that he is leaving the LLLVM project, citing unhappiness with changes in the community: specifically the adoption of a code of conduct and involvement with Outreachy. A range of LLVM developers expressed sadness about this decision, and paid tribute to Rafael's contributions.

• Dean Michael Berris shares the current plans for Sydney developers/users meetups. The plan is to start regular workshop/study-group meetups, and to aim for a 1-day event in October.

• Welcome to Mikhail Ramalho who will be working with the Clang static analyzer and Z3 SMT solver as part of Google Summer of Code.

• Alexandros Lamprineas wonders about best practice for using auto-generated test assertions, such as those generated by update_llc_test_checks.py.

• Walter Lee has ported ASan to Myriad RTEMS, has shared a design document and is seeking feedback on the patch series.

LLVM commits

• The SystemZ backend no longer users glue to represent condition code dependencies and instead represents them as normal values during SelectionDAG matching. r331202.

• The GlobalISel emitter has been updated to reflect the new representation of extending loads. r331601.

• llvm-mca gained a test that demonstrates support for generating instruction tables for in-order CPUs. r331169.

Clang commits

• Initial support was added for the proposed char8_t type. This is controlled by the flag -fchar8_t and is subject to change. r331244.

• The MachineOutliner can now be explicitly enabled for AArch64 using -foutline. r331370.

• getConstraintRegister was implemented for ARM and AArch64, allowing an error to be generated if there are conflicts between the clobber list and input/output lists for inline assembly. r331164.

Other project commits

• The WebAssembly linker now supports DWARF sections. r331566.

• LLD gained support for the ThinLTO plugin options thinlto-index-only and thinlto-prefix-replace. r331405.

• Code comments in LLDB have been reflowed, as the previous clang-formatting of the codebase left some paragraphs in a hard to read state. r331197.