LLVM Weekly - #554, August 12th 2024
If you prefer, you can read the canonical version of this issue at http://llvmweekly.org/issue/554.
Welcome to the five hundred and fifty-fourth 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 http://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to asb@asbradbury.org, @llvmweekly or @asbradbury on Twitter, or @llvmweekly@fosstodon.org or @asb@fosstodon.org.
News and articles from around the web and events
Registration is now open for the 2024 LLVM Developers’ Meeting, and the full/half day workshops ahve been announced. More details have been posted about the LLVM 
ML Workshop, and the talk submission deadline for the mean Dev Meeting has been extended by a single day (today).
Min-Yih Hsu blogged about scheduling models in LLVM.
Ramkumar Ramachandra blogged about auto-vectorization in LLVM and introducing LLVM backends.
The next Toronto LLVM meetup will take place on August 15th and feature talks on “Catalyst: An AOT/JIT compiler for accelerated quantum computing in Python” and “DPC++ SYCL Compiler”.
The monthly LLVM Bay Area meetup is taking place today (12th August).
According to the LLVM calendar in the coming week there will be the following:
- Office hours with the following hosts: Aaron Ballman, Alexey Bader, Kristof Beyls, Johannes Doerfert.
- Online sync-ups on the following topics: pointer authentication, new contributors, OpenMP, Flang, BOLT, RISC-V, MLIR, embedded toolchains.
- For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.
On the forums
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“higher-performance” proposed adding a new attribute to Clang that ensures a warning is produced if fields aren’t explicitly initialised.
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“rahulana-quic” initiated an RFC on adding a new structure layout optimization pass which has generated a fair bit of discussion.
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“n-omer” started an RFC discussion on implementing a way to inform the compiler that a function is a fiber suspend point.
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Maksim Kita proposed adding a
force_vectorizepragma to Clang. -
Chaitanya Shahare is still seeking feedback on the proposed llvm.org website redesign.
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Schrodinger Zhu kicked off a discussion on flat-combining in LLVM’s libc]([libc][RFC] Introduce MCS-based Flat-Combining Lambda Lock).
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The question of renaming flang-new to flang was raised again.
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Yaxun (Sam) Liu suggested adding a new atomic progma to Clang to allow greater control over atomics lowering.
LLVM commits
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Basic block numbers are now used to store dominator tree nodes in a vector. c2f92fa, d871b2e.
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If
--skip-line-zerois passed, LLVM symbolizer can now report the nearest non-zero line number if it can’t get the correct line number. 0886440. -
The ExpandVP pass was merged into PreISelIntrinsicLowering. fa92d51.
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The NVPTX backend gained support for Volta’s sequentially consistent load and store operations. f55abd5.
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A LoongArchMergeBaseOffset pass was added. b2e69f5.
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riscv-experimental-rv64-legal-i32 was backed out for now as it’s not receiving active development attention. ca7ad38.
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A
merge-release-pr.pyscript was added to help release managers merge backports PRs. f3e950a. -
IRBuilder now generates
nuwGEPs for struct member accesses. 94473f4.
Clang commits
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Builtins were added for the AVX10.2-SATCVT instructions. 80721e0.
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Single-element accesses to GCC vector/ext_vector_type objects can now be used in constant expressions. 7753429.
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attribute((rvv_vector_bits(N)))can now be used whenN < 8. 635d20e.
Other project commits
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LLVM’s libopenmp can now compile and run under the emscripten WebAssembly toolchain. f7b2c2e.
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Spin lock family functions were added to LLVM’s libc. 03841e7.
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“Edit this page” links were added to LLDB’s generated documentation. 2771ce8.
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MLIR’s documentation for scalable vectors was updated. 673604a.
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mlir-opt now has a
--list-passesoption. 5e6d5c0.