Alex Bradbury via llvm-dev
2020-Dec-07 18:39 UTC
[llvm-dev] LLVM Weekly - #362, December 7th 2020
LLVM Weekly - #362, December 7th 2020 ==================================== If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/362>. Welcome to the three hundred and sixty-second 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 A couple more videos from the 2020 LLVM Developers' Meeting were added to the [YouTube channel](https://www.youtube.com/channel/UCv2_41bSAa5Y_8BacJUZfjQ). ## On the mailing lists * Mike Edwards [provided an update on the transition to the 'main' branch](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147053.html), linking to the [LLVM Foundation page on the transition](https://foundation.llvm.org/docs/branch-rename/). * There's been substantial new discussion on the RFC about `SVec<T>` and `Vec<T>` convenience wrappers. Chris Lattner [summarises the parallel discussions taking place in this thread](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147006.html). * Tom Stellard explained [how to disable GitHub Action notifications](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146953.html), noting people may be getting notifications due to an action being introduced to help with the transition to the 'main' branch name. * Nikita Popov [proposes changing the LLVM coding style for argument alignment](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147084.html). * Rong Xu posted an RFC on [adding a 'hot' function attribute to LLVM IR](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147104.html) in addition to the currently supported 'cold' attribute. * Armand Behroozi is [seeking guidance on using LLVM to collect dynamic spill and instruction counts from LLVM](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146962.html). Quentin Colombet [suggests combining PGO data with emitted assembly annotations](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146967.html). * Min-Yih Hsu [reports that the M68k patches are almost ready to land](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147110.html), and is seeking additional help in reviewing and approving this patches. * ORC JIT Weekly #27 [is out](http://lists.llvm.org/pipermail/llvm-dev/2020-December/147183.html), giving an update on the status of the ORC runtime. ## LLVM commits * Initial infrastructure for code generation of the RISC-V V extension was committed. [5baef63](https://reviews.llvm.org/rG5baef6353e8). * Documentation was added for the AMDGPU object V4 ABI. [04424c6](https://reviews.llvm.org/rG04424c69bc7). * A new attribute, `llvm.loop.vectorize.scalable.enable` was added. [71bd59f](https://reviews.llvm.org/rG71bd59f0cb6). * Prologue/epilogue sequences are better optimised for VE. [686988a](https://reviews.llvm.org/rG686988a50f5), [6834b3d](https://reviews.llvm.org/rG6834b3d6d52). * A pseudo probe implementation pass was introduced, as part of the ongoing context-sensitive sample PGO work. [64fa8cc](https://reviews.llvm.org/rG64fa8cce225). * The MemCpyOptimizer was ported to MemorySSA. [624af93](https://reviews.llvm.org/rG624af932a80). * Epilogue vectorization was added to the loop vectorizer. [a7e2c26](https://reviews.llvm.org/rGa7e2c269399). * Support was added for the experimental RISC-V half precision floating-point extension (Zfh). [f7bc7c2](https://reviews.llvm.org/rGf7bc7c2981d). * The 'code' type was removed from TableGen. [415fab6](https://reviews.llvm.org/rG415fab6f67b). * The BPF backend gained support for atomics. [286daaf](https://reviews.llvm.org/rG286daafd651). * An arm64e AArch64 sub-arch for Pointer Authentication was defined. It defaults to the apple-a12 CPU. [f77c948](https://reviews.llvm.org/rGf77c948d56b). * llvm-objdump for RISC-V will now print pc-relative immediates as absolute addresses. [ad923ed](https://reviews.llvm.org/rGad923edfc1c). ## Clang commits * The new clang-format option PenaltyIndentedWhitespace assigns a penalty to each character of new whitespace indentation, which in practice will alter thresholds for preferring right-indenting multiple lines vs introducing a line-break before the block. [1e4d6d1](https://reviews.llvm.org/rG1e4d6d1c1ff). * 'auto' can now be specified as the `-fdiagnostic-hotness-threshold`. [93dc1b5](https://reviews.llvm.org/rG93dc1b5b8cb). * CUDA overloading resolution was fixed. [acb6f80](https://reviews.llvm.org/rGacb6f80d96b). * clang-format's handling of C++ concepts was improved. [840e651](https://reviews.llvm.org/rG840e651dc6d). * clang-tidy gained a concurrency-mt-unsafe check that warns about usage of functions known to be thread-unsafe. [cac5be4](https://reviews.llvm.org/rGcac5be495ed). ## Other project commits * LLVM's libc gained implementations of mktime, strncpy, and hypot. [6f0f844](https://reviews.llvm.org/rG6f0f844e9af), [60cef89](https://reviews.llvm.org/rG60cef893627), [3b487d5](https://reviews.llvm.org/rG3b487d51e2e). * A C++2b status page was added to libcxx. [590bbfe](https://reviews.llvm.org/rG590bbfe0d80).