LLVM Weekly - #280, May 13th 2019

Welcome to the two hundred and eightieth 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

The next LLVM Developers' Meeting is scheduled for October 22-23rd in San Jose.

An LLVM Social will take place in Chicago at a yet-to-be determined date. Use the linked Doodle poll or meetup page to indicate your preference.

GDB 8.3 has been released.

On the mailing lists

• Alexey Sidorin provides an update on support for a matcher-like checker API.

• Praveen Velliengiri is a GSoC student working on speculative compilation in ORC, and introduces themselves here. Seiya Nuta will be working on improving LLVM binary utilities.

• Paul Robinson suggests the removal of REQUIRES: no* instances in LLVM codebases as they may mislead peope into thinking the no* prefix is understood by lit, and these cases can be better handled using UNSUPPORTED:.

• Simon Pilgrim is seeking feedback on the current scan-build reports on LLVM and interest in fixing the reported issues. Artem Dergacehv indicates a GSoC project will be looking at static analyzer false positives.

LLVM commits

• LoopSimplify learned to preserve MemorySSA. r360270.

• Support was added for AVX512_BF16 instructions, supported by the upcoming Cooper Lake microarchitecture. r360017.

• On the ARM backend, register copies are now glued to tail calls. As described in the commit message, the previous logic wasn't quite correct. If your out-of-tree backend copied ARM you may want to review. r360099.

• InstPrinter was moved to MCTargetDesc for various backends for consistency with backends where this is necessary in order to avoid a circular dependency. r360484, r360485, r360486, r360487, r360488, and more.

Clang commits

• P1009R2 from C++20 was implemented, allowing the array bound in an array new expression to be omitted. r360006.

• C++20 explicit(bool) support was committed. r360311.

• The -gz and -wA,--compress-debug-sections options were updated to use gABI compression rather than zlib-gnu. r360403.

• clangd gained an intermediate representation of formatted text. r360151.

Other project commits

• The standalone version of the scudo allocator gained a Quarantine implementation to hold chunks of memory prior to releasing them for potential reuse. r360163.

• The LLDB python reference page was ported over from the old LLDB website. r360386.