Alex Bradbury via llvm-dev
2018-Dec-10 20:47 UTC
[llvm-dev] LLVM Weekly - #258, December 10th 2018
LLVM Weekly - #258, December 10th 2018 ===================================== If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/258>. Welcome to the two hundred and fifty-eighth 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 7.0.1-rc3 [has been tagged](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128366.html). The intent is that this is the last release candidate. Stephen Kelly has blogged on [using build tools with clang-tidy](https://blogs.msdn.microsoft.com/vcblog/2018/11/27/exploring-clang-tooling-using-build-tools-with-clang-tidy/). ## On the mailing lists * John Brawn [writes](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128299.html) about a fascinating regalloc issue. A regression in bzip2 is triggered when there is one more available register, resulting in worse allocation behaviour. Quentin Colombet [provides some insight](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128309.html). * Adam Nemet [kicks off](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128322.html) a second round of discussions on matrix support in LLVM. This new proposal takes a more scaled back approach. * Anastasia Stulova has started an RFC thread on [preserving the address space of 'this' in C++ methods](http://lists.llvm.org/pipermail/cfe-dev/2018-December/060470.html). * Lingda Li is seeking feedback for an RFC on [the implementation of the OpenMP 5.0 declare mapper directive](http://lists.llvm.org/pipermail/cfe-dev/2018-December/060476.html). * Hans Wennborg has proposed the [8.0 release schedule](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128186.html), which would see the branch taking place on 16th January and final tag on 27th Feb. * James Y Knight is keen on [moving forwards with the plan for the git monorepo](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128196.html). After another week with [no extra concerns](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128389.html), it looks like there may be consensus. * Tom Stellard [reports](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128246.html) that a bug fix for 7.0.0 will necessarily lead to an ABI change for a clang-build libLLVM-7.so. He proposes leaving the fix from 7.0.1 and shipping a special 7.0.2/7.1.0 release so users have the option of accepting this ABI change or not. * Michael Kruse [proposes](http://lists.llvm.org/pipermail/llvm-dev/2018-December/128276.html) to no longer use LoopIDs as identifiers. ## LLVM commits * A new llvm.experimental.widenable.condition intrinsic was added. This allows the choice between two alternative correct solutions for the same problem or to express guards. [r348593](https://reviews.llvm.org/rL348593). * It is now possible to mark variadic register operands as defs. [r348114](https://reviews.llvm.org/rL348114). * Initial support for the 'TAPI' TextAPI proposal landed. This allows conversion between binary shared object stubs and textual counterparts. [r348170](https://reviews.llvm.org/rL348170). * SimpleLoopUnswitch learned to preserve MemorySSA. [r348263](https://reviews.llvm.org/rL348263). * A new interface was introduced to observe changes in GISel passes. [r348406](https://reviews.llvm.org/rL348406). * The IR constant folder no longer assumes all functions are 4-byte aligned. [r348571](https://reviews.llvm.org/rL348571). ## Clang commits * Support for pretokenized headers was removed. This was an experimental feature that was ultimately considered failed. [r348266](https://reviews.llvm.org/rL348266). * Portability of the Clang python utility scripts to Python 3 was improved. [r348126](https://reviews.llvm.org/rL348126), [r348127](https://reviews.llvm.org/rL348127), [r348129](https://reviews.llvm.org/rL348129), and more. * The iterator checker learned to warn on decrements past the begin() and end() of containers. [r348425](https://reviews.llvm.org/rL348425). ## Other project commits * DragonFlyBSD and OpenBSD support was added to the OpenMP runtime. [r348725](https://reviews.llvm.org/rL348725), [r348726](https://reviews.llvm.org/rL348726). * The WebAssembly lld linker gained support for the event section specified in the exception handling proposal. [r348703](https://reviews.llvm.org/rL348703).