LLVM Weekly - #642, April 20th 2026
Welcome to the six hundred and forty-second 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 via email: asb@asbradbury.org, or Mastodon: @llvmweekly@fosstodon.org / @asb@fosstodon.org, or Bluesky: @llvmweekly.org / @asbradbury.org.
News and articles from around the web and events
The next LLVM Bay Area Monthly meetup will take place on 27th April.
The FOSSY 2026 toolchain track is accepting talk submissions.
According to the LLVM Calendar in the coming week there will be the following:
- Office hours with the following hosts: Kristof Beyls, Johannes Doerfert. Amara Emerson.
- Online sync-ups on the following topics: formal specification working group, vectorizer improvements, libc++, OpenMP, Flang, SPIR-V, RISC-V, LLVM embedded toolchains, HLSL, LLVM libc math.
- For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.
On the forums
A number of EuroLLVM round table summaries are appearing (thank you to those taking and posting notes!). Posts were made for pointer arithmetic, LLVM libc, debugger / debug info (with illustrations!), full restrict / ptr provenance / alias analysis, MLIR canonicalisation, MLIR lighthouse, EmitC, early exit from MLIR regions.
Yaxun (Sam) Liu proposed infrastructure to record LLVM IR snapshots in an SQlite database.
Chi-Chun Chen posted an RFC on supporting aggressive inlining inside OpenMP SIMD loops.
Jeff Bailey is looking to support coverage in LLVM’s libc.
Madhur started a discussion on enforcing that all .enable metadata nodes should be in single-operand format for reasons of consistency.
Bruno Cardoso Lopes provided an update on the status of ClangIR upstreaming with updated figures for how much of the test-suite compiles and runs and a listing of prioritised blocking issues.
Volodymyr Turanskyy is seeking to remove the use of the clang-runtimes subfolder in the BareMetal driver as it is inconsistent with other drivers. If this might affect you, please speak up.
Jeff Bailey is seeking feedback on re-organising the LLVM libc website.
Arthur Eubanks suggests adding
MandatoryPassInfoMixin/OptionalPassInfoMixinso new pass manager passes are forced to mark the pass as required or not.Momchil Velikov started an RFC thread on doing vectorisation only at LTO time when using LTO.
Vineet Kumar discussed adding floating-point trap handling support to Flang.
LLVM commits
SDPatternMatch gained funnel-shift matchers. 4b4aa3b.
A scheduling model was added for the Arm C1-Ultra. b6c9cbe.
lit has a new
--min-output-intervaloption to rate-limit the curses progress bar, saving bandwidth when used over ssh. c1d6f76.ScalarEpilogueLowering in the loop vectoriser was renamed to EpilogueLowering to avoid confusion given the fact the epilogue could be vectorised. ac2c986.
A target specific AMDGPUNextUseAnalysis pass was added, computing the distance from each instruction to the nearest next use of every live virtual register, which is used to guide register spilling. b9ae015.
Clang commits
OpenMP
#pragma omp splitwas implemented. 1d18740.Intrinsics were added for the RISC-V Zvzip extension. 6a88394.
New Clang option were added to control the mechanism used by Control Flow Guard on Windows. 5306884.
Clang driver support was added for SerenityOS. 934f795.
PowerPC elliptic curve cryptography builtins are now supported. c486538.
The readability-redundant-lambda-parameter-list clang-tidy check was added, which will remove redundant empty parameter lists from lambda expressions when the rewrite is valid for the active language standard. 96266b7.