Alex Bradbury via llvm-dev
2019-Nov-11 22:07 UTC
[llvm-dev] LLVM Weekly - #306, November 11th 2019
LLVM Weekly - #306, November 11th 2019 ===================================== If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/306>. Welcome to the three hundred and sixth 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. As many of you know, I co-founded a not-for-profit collaborative engineering company, lowRISC. We've had a [huge announcement](https://www.lowrisc.org/blog/2019/11/announcing-opentitan-the-first-transparent-silicon-root-of-trust/) last week, publicly announcing the world's first open source silicon root of trust - OpenTitan. ## News and articles from around the web The call for papers for the 4th LLVM performance workshop at CGO [has been posted](http://lists.llvm.org/pipermail/llvm-dev/2019-November/136649.html). The deadline for submissions in teh 5th Jan, and the workshop will take place on Feb 23rd in San Diego. Herb Sutter has posted a [trip report from the Autumn ISO C++ standard meeting](https://herbsutter.com/2019/11/09/trip-report-autumn-iso-c-standards-meeting-belfast/). ## On the mailing lists * Mehdi Amini started a thread on [allowing LLVM contributions through GitHub pull requests](http://lists.llvm.org/pipermail/llvm-dev/2019-November/136579.html). This generated a huge amount of discussion, pro and con. * Levi Aul is seeking feedback on supporting an [unlimited width integer type](http://lists.llvm.org/pipermail/cfe-dev/2019-November/063838.html). David Chisnall [provided some thoughts](http://lists.llvm.org/pipermail/cfe-dev/2019-November/063852.html). * Ehud Katz posted an RFC on [exposing the waymarking algorithm](http://lists.llvm.org/pipermail/llvm-dev/2019-November/136491.html) from the 'Use' class as an independent utility. * Bardia Mahjour sent out the [loop optimisation working group meeting minutes](http://lists.llvm.org/pipermail/llvm-dev/2019-November/136603.html) for last week. ## LLVM commits * The 'freeze' instruction was added to LLM IR, which can be used to stop propagation of undef and poison values. [58acbce](https://reviews.llvm.org/rG58acbce3def), [2d21068](https://reviews.llvm.org/rG2d21068d9fa). * GlobalISel saw a number of documentation improvements including docs on KnownBits analysis, debugging with the block extractor, and GMIR and GenericOpCode references. [312932a](https://reviews.llvm.org/rG312932a3346), [7060840](https://reviews.llvm.org/rG7060840bc9c), [ad0dfb0](https://reviews.llvm.org/rGad0dfb0a253). * SystemZ gained support for the GHC calling convention. [22f9429](https://reviews.llvm.org/rG22f9429149a). * DFAPacketizer was updated to allow up to 64 functional units. [39525a6](https://reviews.llvm.org/rG39525a67238). * DWARFDebugLocLists started to moved to an incremental parsing model. [e1f8c8a](https://reviews.llvm.org/rGe1f8c8a16f4). * InstCombine will now canonicalise shift+logic+shift to reduce the dependency chain. [d9ccb63](https://reviews.llvm.org/rGd9ccb6367a1). * The `-consider-local-interval-cost` options for the greedy register allocator is now enabled by default for AArch64. This has very minor impact which the commit message documents. [f649f24](https://reviews.llvm.org/rGf649f24d388). * Development of the data dependency graph continues with the addition of Pi Blocks. [f0af11d8](https://reviews.llvm.org/rGf0af11d86f8). ## Clang commits * Syntax nodes were added for most comment statements. [58fa50f](https://reviews.llvm.org/rG58fa50f4370). * Clang's sysroot computation will now do a better job for the RISC-V target in the case that no GCC install is detected. [de61aa3](https://reviews.llvm.org/rGde61aa3118b). ## Other project commits * The old Python-based build system was dropped from libclc. [d6e0e6d](https://reviews.llvm.org/rGd6e0e6d255a). * std::midpoint was optimised for integers. [586952f](https://reviews.llvm.org/rG586952f4cef).