LLVM Weekly - #670, November 2nd 2026

Welcome to the six hundred and seventieth 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.

Saleem Abdulrasool wrote about ABIs on the Browser Company Speaking in Swift blog.

According to the LLVM Calendar in the coming week there will be the following:

Office hours with the following hosts: Quentin Colombet, Renato Golin.
Online sync-ups on the following topics: formal specification, MLIR C/C++ frontend working group, pointer authentication, lifetime safety, Clang static analysis, OpenMP, Clang C and C++ language working group, Flang, RISC-V, LLVM embedded toolchains, HLSL, MLGO, LLVM libc math.
For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.

Anton Korobeynikov noted that the Graphite review tool will be disabled for the LLVM project as they no longer offer discounted or free plans for open source organisations.
Notes are available from various round tables / workshops at last week’s Dev Meeting: debug info, LLVM hearts ML, and the RISC-V roundtable.
Michael Kruse provided an update on the effort to improve Flang compilation speed by de-templatising noting that a key PR will land soon. “Flang should not behave any differently, but builds up to 46% faster (gcc, without precompiled headers)”.
Ralf Jung started an RFC discussion on adding a freezing memcpy which would be part of the story for exposing freeze to programmers in Rust.
Joshua Haberman posted an RFC on tail_chaincc, a maximum efficiency tailcall convention. It combines the callee-cleanup mechanics of tailcc with the register optimisations of preserve_none and is intended to be used with [[clang::musttail]].
paperchalice wrote a v2 RFC on TableGen support for RegisterBankInfo, providing a way to define register bank mapping rules by matching TypedOperands.
Federico Bruzzone posted an MLIR RFC on unifying masking in the Vector dialect.
Konstantin Zhuravlyov started a discussion on vendor-owned pre-merge testing for LLVM PRs.

LoopStrengthReduce learned to rewrite branches to eq/ne with an immediate for targets like RISC-V with the Zibi (immediate branch extension) enabled. 0b56c8e.
llvm-dwarfutil now supports --compress-debug-sections. cc6b3b5.
An X86 pass was added to insert sfence after non-temporal stores. 238ef21.
A number of fixes were made to tail call support on AArch64 Windows. 3c956bd.
The ‘debugger-tuning’ module flag was introduced. 738215b.
LLVM’s AI contribution policy is now referenced on the ‘how to submit a bug’ page. 5661d4f.
llvm.raw.sections named metadata was added for embedding arbitrary binary data into named sections of the output object file. 39cd74f.
The LiveVariables analysis was removed, described as “12 years overdue” in the commit message! 93f05d7.
Malloc promotion was removed due to being buggy and rarely profitable. e2089b0d.
VPlan now computes branch costs. 999b73d.

Bolt’s webpage styling was updated. d35f657b.
LLVM’s libc now has double precision sinh, cosh, and tanh correctly rounded for all rounding modes. 1866d4c, 075a6cb, ff9ad99.
LLVM libc’s regex implementation is being fleshed out. ad46922, adb8031.