LLVM Weekly - #651, June 22nd 2026

Welcome to the six hundred and fifty-first 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.

The call for proposals is now open for the 2026 US LLVM Developers' Meeting, closing on July 14th. The Dev Meeting itself will take place on October 26th-28th in Santa Clara. Additionally the set of workshops has been announced, registration is already open, and applications for student travel grants are open.

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

Office hours with the following hosts: Johannes Doerfert, Amara Emerson.
Online sync-ups on the following topics: Flang, modules, lifetime safety, LLVM/Offload, OpenMP for flang, HLSL, reflection, LLVM libc math.
For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.

Nikita Popov proposed an allocator provenance model. “We model memory allocation as ‘creating’ provenance and memory deallocation as ‘destroying’ provenance. This is reasonably well-defined in cases where the implementation of the allocator lives in a different module. However, it becomes unclear what exactly these terms mean when the allocator is visible in the same module. This RFC is an attempt to specify the provenance semantics of allocators in LLVM, and provide the means to correctly handle them even if asymmetrically inlined.”
Bruno Cardoso Lopes provided another status update on ClangIR upstreaming. An -fclangir-built clang can now compile about 93% of the translation units in the clang build graph (although the correctness of the compiled TUs has not been tested!).
Jan Newger and Snehasish Kumar posted an RFC on adding the CopySanitizer for detecting unnecessary object copies at runtime.
LLVM 22.1.8 was released.
Petr Hosek proposed raising the minimum required CMake version to 3.31. All respondents are in favour so far.
Adam Siemieniuk posted an MLIR RFC on adding a new linalg.scaled_contract operation.
Nikita Popov is querying if anyone is using the IROutliner and would step up to maintain it, in order to prevent it being removed.
Vittorio Burani started an RFC Discussion on upstreaming support for the RISC-V OpenHW Group Core-V XCV vendor extensions as implemented in the CV32E40P core.

llvm.pext and llvm.pdep intrinsics were added as portable forms of x86_64 pext/pdep or AArch64 bext/bdep instructions. bf8b778, 4b2a02d.
Support code was added for determining the alignment requirements of CHERI capabilities. 7dc09d0.
Initial definitions were added for the HiSilicon HIP12 AArch64 core. d8735012.
A number of std::unordered_{map,set} uses were replaced with Dense{Map,Set}. 37881c6, 3746f3e.
An SDag expansion was added for llvm.convert.to.arbitrary.fp. 041262d.
A DXILRemoveUnusedResources pass was added. 5dc8ac2.

Parallel DWARF processing was added to BOLT, intending to speed up --update-debug-sections for large binaries. d3ac9b5.
A new libcxx configuration option was added for changing the default deque block size. ad9ecc4.
Documentation was added to libcxx for the procedure to be followed after a WG21 meeting to properly track papers. 4a9cb1f.
A build_and_run test utility was added to LLDB’s test infrastructure to avoid repeated boilerplate for tests. 74ac7c9.
LLDB’s MCP server now has unit tests. a85441c.
The byte type was added to MLIR’s LLVM dialect. e559d43.
MLIR’s grew a docs page linking to external tutorials. b87fe38.