LLVM Weekly - #330, Apr 27th 2020
Welcome to the three hundred and thirtieth 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
Erich Keane wrote for the LLVM blog about the recently added _ExtInt
feature,
providing support for exact bitwidth integer types in Clang.
On the mailing lists
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Tom Stellard returned to the topic of switching from Bugzilla to GitHub issues, reporting that support for subscribing to notifications for specific issue labels will be provided through GitHub Actions. This spawned a long thread, mostly focused on the question of how to handle existing bugs and possibilities for keeping consistent numbering or using redirects.
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Martin Liška announces C-Vise, a Python fork of the C-Reduce tool.
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Kees Cook proposed making -ftrivial-auto-var-init=zero a first-class option, reporting a number of vendors using zero initialisation in production code (with more responding later in the thread). There were many responses on this thread and a consensus has yet to form, though JF Bastien indicated interest in seeing the work on optimising pattern initialisation finished to allow a fuller comparison.
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Sjoerd Meijer kicked off a long thread on the clang mailing list about mtune. David Greene suggested not following GCC rigidly.
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ORC JIT Weekly #13 is out. Discord user @Juicebox has written a project to enable PDB debugging on Windows with ORC and MCJIT.
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Chris Tetreault provides an update on refactoring the class hierarchy of VectorType.
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Tom Stellard shares the proposed 10.0.1 release schedule. This would see rc1 tagged on May 18th, rc2 on June 18th, and 10.0.1-final on June 25th.
LLVM commits
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MC layer support for the Armv8.6-a matrix multiply extension was added. 832cd74, e714683.
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TargetTransformInfo::getOperationCostwas removed and merged into getUserCost. ee959dd. -
The MachineVerifier is now run after more passes. 46a52ff.
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The integration of compiler extensions into the build system was updated. 8f766e3.
Clang commits
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The time profiler script will now emit a beginningOfTime parameter that can be used for combining events from different processes while preserving their relative timing. 2899103.