Alex Bradbury via llvm-dev
2017-Jan-23 10:55 UTC
[llvm-dev] LLVM Weekly - #160, Jan 23rd 2017
LLVM Weekly - #160, Jan 23rd 2017 ================================ If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/160>. Welcome to the one hundred and sixtieth 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](http://asbradbury.org). 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 4.0.0-rc1 has [now been tagged](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109217.html). Details are now [available](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109374.html) for EuroLLVM2017 student travel grants. The Polly project has gained a new ARM64 buildbot, sponsored by the Qualcomm Innovation Center. This [blog post](http://pollylabs.org/2017/01/18/New-ARM64-Buildbot-for-Polly.html) goes into some extra detail about Polly's continuous integration setup. The next Cambridge LLVM social will [take place](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109163.html) on Wednesday, Jan 25th. The next [Berlin LLVM social](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109384.html) will take place on the 26th of January. ## On the mailing lists * Quentin Colombet has shared a [status update on global instruction selection](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109366.html). The plan remains to enable it by default for `-O0` on AArch64 by the end of the year. * Vassil Vasilev is [looking for help](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109080.html) in revitalising the list of open LLVM projects. * There have been further discussion on the proposal for IR-level region annotations. I can't summarise it all here, but the input from [the Tapir and PIR team](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109264.html) and [Vikram Adve's response](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109276.html) is worth reading. * John Regehr, as secretary of the LLVM Foundation, has [written to confirm Chris Lattner will remain on the LLVM Foundation Board of Directors](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109138.html). The question was raised due to the fact Chris has recently announced a move from Apple to Tesla. * The discussion about enabling GlobalISel by default has continued, with Quentin Colombet giving a [helpful summary](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109279.html) of the key points. * Dmitry Golovin reports on his [attempts to link the Linux kernel with LLD](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109288.html). A working kernel isn't produced, but with the listed changes the buidl process does at least complete. * Piotr Padlewski has proposed an RFC on [improving how vtable loads are decorated](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109332.html) in order to handle devirtualisation better. * Mikhail Zolotukhin has shared a [new analysis of recent compile time regressions in LLVM](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109188.html). * Discussion on the git transition continues, with Chris Lattner [advocating the monorepo approach](http://lists.llvm.org/pipermail/llvm-dev/2017-January/109115.html). ## LLVM commits * A new `-debug-info-for-profiling` option was added. This will cause a larger amount of debug info to be generated which will be used in profile-guided optimisations. [r292457](http://reviews.llvm.org/rL292457). * Partial unrolling now has its own threshold. [r292293](http://reviews.llvm.org/rL292293). * Literals generated AArch64 targets are now constructed started from their little end, in order to meet the recommendation of the Cortex A57 software optimisation guide. [r292422](http://reviews.llvm.org/rL292422). * The LiveRegUnits class has been factored out of RegisterScavenging. [r292542](http://reviews.llvm.org/rL292542). * Support for profile-guided optimisation in the new inliner has been improved. [r292666](http://reviews.llvm.org/rL292666). * LoopSink has been ported to the new pass manager. [r292589](http://reviews.llvm.org/rL292589). ## Clang commits * Support for constexpr evaluation of string builtins was documented. [r292558](http://reviews.llvm.org/rL292558). * Sadly, Clang's Python bindings don't currently work in Python 3. They will now explicitly check the Python version an raise an error if it's not '2'. [r292247](http://reviews.llvm.org/rL292247). * Support for OpenMP 'target parallel' on the host and the NVPTX device was added. [r292419](http://reviews.llvm.org/rL292419), [r292428](http://reviews.llvm.org/rL292428). ## Other project commits * There have been a number of improvements for CMake and Lit with libcxx on Windows. [r292157](http://reviews.llvm.org/rL292157). * The 'buildit' and 'testit' scripts will be removed from libcxx in the next week. [r292181](http://reviews.llvm.org/rL292181). * A new macro for succinct logging was added to the LLDB codebase. [r292360](http://reviews.llvm.org/rL292360).