[CLANG] Update LLVM version from 21.1.4 to 21.1.8

[smuzaffar]

No description provided.

[smuzaffar]

please test using full cmssw

[cmsbuild]

A new Pull Request was created by @smuzaffar for branch IB/CMSSW_16_1_X/clang.

@akritkbehera, @iarspider, @raoatifshad, @smuzaffar can you please review it and eventually sign? Thanks.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.
cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[smuzaffar]

+externals

good to go in CLANG_X IBs

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next IB/CMSSW_16_1_X/clang IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @sextonkennedy, @mandrenguyen, @ftenchini (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12ed56/51131/summary.html
COMMIT: 8ca1235
CMSSW: CMSSW_16_1_CLANG_X_2026-02-04-2300/el8_amd64_gcc13
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmsdist/10324/51131/install.sh to create a dev area with all the needed externals and cmssw changes.

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:

• @waredjeb Fix seed column in LayerCluster SoA  cmssw#50017
• @smuzaffar Drop Alignment/Cocoa packages cmssw#50016
• @CMSTrackerDPG HLT digi morphing fix cmssw#49991
• @smuzaffar GCC15: Fix build error array subscript -1 is below array bounds cmssw#50009
• @goblirsc Update tracker alignment algs to new Millepede+GBL versions cmssw#49963
• @AdrianoDee ParkingHH0 2025 Data Workflows cmssw#50028
• @raoatifshad [GCC15]: (alca-db) Fix build warnings in CalibTracker/SiStripQuality … cmssw#50030
• @makortel Escape special characters in most JobReport XML elements cmssw#50024
• @goblirsc Add new "Mille" package to externals, update Millepede-II and GBL  #10310
• @cms-sw SCRAM: proint an error message if there is invalid file/directory in src tree #10321

You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12ed56/51131/git-recent-commits.json
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12ed56/51131/git-merge-result

Comparison Summary

Summary:

• You potentially added 181 lines to the logs
• Reco comparison results: 99569 differences found in the comparisons
• DQMHistoTests: Total files compared: 52
• DQMHistoTests: Total histograms compared: 4029600
• DQMHistoTests: Total failures: 465267
• DQMHistoTests: Total nulls: 255
• DQMHistoTests: Total successes: 3564058
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 1.5430000000000015 KiB( 51 files compared)
• DQMHistoSizes: changed ( 10224.0 ): -0.171 KiB SiStrip/MechanicalView
• DQMHistoSizes: changed ( 13034.0 ): 1.470 KiB SiStrip/MechanicalView
• DQMHistoSizes: changed ( 17034.0,... ): 1.762 KiB SiStrip/MechanicalView
• DQMHistoSizes: changed ( 2022.0030001,... ): -0.012 KiB JetMET/SUSYDQM
• DQMHistoSizes: changed ( 2023.0020001,... ): -0.008 KiB JetMET/SUSYDQM
• DQMHistoSizes: changed ( 2024.0010001 ): -0.004 KiB JetMET/SUSYDQM
• DQMHistoSizes: changed ( 2024.0040001 ): 0.027 KiB JetMET/SUSYDQM
• DQMHistoSizes: changed ( 2024.0060001 ): -0.035 KiB JetMET/SUSYDQM
• DQMHistoSizes: changed ( 250202.181 ): 0.278 KiB SiStrip/MechanicalView
• DQMHistoSizes: changed ( 25202.0 ): -0.415 KiB SiStrip/MechanicalView
• DQMHistoSizes: changed ( 7.3 ): ...
• Checked 222 log files, 193 edm output root files, 52 DQM output files
• TriggerResults: found differences in 18 / 50 workflows