F45 Change Proposal: LLVM 23 (system-wide)

Project Discussion Change Proposals
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1

LLVM 23

This is a proposed Change for Fedora Linux.
This document represents a proposed Change. As part of the Changes process, proposals are publicly announced in order to receive community feedback. This proposal will only be implemented if approved by the Fedora Engineering Steering Committee.

Wiki
Announced

:link: Summary

Update all llvm sub-projects in Fedora Linux to version 23.

:link: Owner

:link: Current status

  • Targeted release: Fedora Linux 45
  • Last updated: 2026-06-12
  • [ Announced]
  • [ Discussion thread]
  • FESCo issue:
  • Tracker bug:
  • Release notes tracker:

:link: Detailed Description

All llvm sub-projects in Fedora will be updated to version 23. There will be a soname version change for the llvm libraries, and an llvm22 compat package added to ensure that packages that currently depend on clang and llvm version 22 libraries will continue to work.

Other notable changes:

  • libclc merged into llvm: The libclc RPMs are now built from the llvm SRPM

:link: Planned Schedule

Our plan is to push 23.1.0 into Fedora 45 during the Beta Freeze with a Beta Freeze exception.

We are not planning to push earlier release candidates into rawhide because the library ABI is not stabilized until the final 23.1.0 release.

:link: Important Dates

  • Jul 1: Request a Beta Freeze exception for LLVM.
  • Jul 17: Begin building LLVM 23.1.0-rc1 in COPR.
  • Jul 28: Begin building LLVM 23.1.0-rc2 in COPR.
  • Aug 11: Fedora f45 branches created
  • Aug 11: Begin building LLVM 23.1.0-rc3 in COPR.
  • Aug 25: Fedora f45 Beta Freeze
  • Aug 25: Begin building LLVM 23.1.0 in Rawhide and 45 side-tags.
  • Oct 06: Fedora f45 Final Freeze

:link: Feedback

:link: Benefit to Fedora

New features and bug fixes provided by the latest version of LLVM.

:link: Scope

  • Proposal owners:

    • Build and test release candidates of LLVM 23 in COPR.
    • Build and test final release of LLVM 23 in koji.

  • Other developers:

    • Fix build issues found with LLVM-23 or switch their package to use the llvm22 compat libs. The LLVM team will not block Bodhi updates on dependent packages that fail to build or run with LLVM-23. There should be around ~10 weeks between when -rc1 lands in COPR and the Final Freeze for package maintainers to fix issues uncovered with the LLVM-23 update.

  • Release engineering: #Releng issue number

  • Policies and guidelines: N/A (not needed for this Change)

  • Trademark approval: N/A (not needed for this Change)

  • Alignment with the Fedora Strategy:

:link: Upgrade/compatibility impact

Previous versions of Fedora are expected to be automatically updated to LLVM 23.

There has been a discussion upstream between Mesa maintainers and libclc maintainers about changes could impact how Mesa is built. The changes have been reverted, but we need to keep the Mesa Fedora packagers aligned.

:link: Early Testing (Optional)

Do you require ‘QA Blueprint’ support? N

:link: How To Test

:link: User Experience

:link: Dependencies

:link: Contingency Plan

  • Contingency mechanism: (What to do? Who will do it?) If there are major problems with LLVM 23, the compatibility package provide a way for other packages to continue using LLVM 22.
  • Contingency deadline: Final Freeze
  • Blocks release? No

:link: Documentation

LLVM sub-projects in Fedora have been updated to version 23:

  • llvm (now includes libclc)
  • llvm-test-suite

:link: Release Notes

Last edited by @amoloney 2026-06-20T13:05:53Z

Last edited by @amoloney 2026-06-20T13:05:53Z

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