Testing CMSSW build with -fimplicit-constexpr by smuzaffar · Pull Request #10333 · cms-sw/cmsdist

smuzaffar · 2026-02-10T13:11:18Z

As discussed in cms-sw/cmssw#47239 , lets test enabling -fimplicit-constexpr for cms

smuzaffar · 2026-02-10T13:11:29Z

please test using full cmssw

cmsbuild · 2026-02-10T13:11:45Z

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

@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 · 2026-02-10T13:11:46Z

cms-bot internal usage

cmsbuild · 2026-02-10T17:53:59Z

-1

Failed Tests: UnitTests
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b353bf/51225/summary.html
COMMIT: e6d873d
CMSSW: CMSSW_16_1_X_2026-02-10-1100/el8_amd64_gcc13
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmsdist/10333/51225/install.sh to create a dev area with all the needed externals and cmssw changes.

Failed Unit Tests

I found 5 errors in the following unit tests:

---> test test-particleLevel_fromHepMC3 had ERRORS
---> test test-rivet-run had ERRORS
---> test test-rivet-plot had ERRORS
and more ...

Comparison Summary

Summary:

You potentially removed 165 lines from the logs
Reco comparison results: 9 differences found in the comparisons
DQMHistoTests: Total files compared: 52
DQMHistoTests: Total histograms compared: 4031484
DQMHistoTests: Total failures: 90
DQMHistoTests: Total nulls: 0
DQMHistoTests: Total successes: 4031374
DQMHistoTests: Total skipped: 20
DQMHistoTests: Total Missing objects: 0
DQMHistoSizes: Histogram memory added: 0.0 KiB( 51 files compared)
Checked 222 log files, 193 edm output root files, 52 DQM output files
TriggerResults: no differences found

smuzaffar · 2026-02-10T21:30:53Z

@makortel @fwyzard , any idea why building with cmssw -fimplicit-constexpr could have caused [a]

[a]. https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b353bf/51225/unitTests/src/GeneratorInterface/RivetInterface/test/test-rivet-run/testing.log

Thread 1 (Thread 0x15189ecca580 (LWP 2733760) "cmsRun"):
#0  0x000015189e15cae1 in poll () from /lib64/libc.so.6
#1  0x0000151899c468ae in edm::service::InitRootHandlers::stacktraceFromThread() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/pluginFWCoreServicesPlugins.so
#2  0x0000151899c46ab3 in sig_dostack_then_abort () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/pluginFWCoreServicesPlugins.so
#3  <signal handler called>
#4  0x000015186c761e02 in HepMC3::GenEvent::GenEvent(HepMC3::Units::MomentumUnit, HepMC3::Units::LengthUnit) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/external/el8_amd64_gcc13/lib/libHepMC3.so.3
#5  0x000015186d5a4875 in Pythia8HepMC3Hadronizer::generatePartonsAndHadronize() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/pluginGeneratorInterfacePythia8HepMC3Filters.so
#6  0x000015186d5c39dc in edm::GeneratorFilter<Pythia8HepMC3Hadronizer, gen::ExternalDecayDriver>::filter(edm::Event&, edm::EventSetup const&) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/pluginGeneratorInterfacePythia8HepMC3Filters.so
#7  0x000015189f051178 in edm::one::EDFilterBase::doEvent(edm::EventTransitionInfo const&, edm::ActivityRegistry*, edm::ModuleCallingContext const*) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#8  0x000015189f0414e7 in edm::WorkerT<edm::one::EDFilterBase>::implDo(edm::EventTransitionInfo const&, edm::ModuleCallingContext const*) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#9  0x000015189efd05e2 in std::__exception_ptr::exception_ptr edm::Worker::runModuleAfterAsyncPrefetch<edm::OccurrenceTraits<edm::EventPrincipal, (edm::TransitionActionType)1> >(std::__exception_ptr::exception_ptr, edm::OccurrenceTraits<edm::EventPrincipal, (edm::TransitionActionType)1>::TransitionInfoType const&, edm::StreamID, edm::ParentContext const&, edm::OccurrenceTraits<edm::EventPrincipal, (edm::TransitionActionType)1>::Context const*) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#10 0x000015189efd28e4 in edm::SerialTaskQueue::QueuedTask<edm::SerialTaskQueueChain::push<edm::Worker::RunModuleTask<edm::OccurrenceTraits<edm::EventPrincipal, (edm::TransitionActionType)1> >::execute()::{lambda()#1}&>(tbb::detail::d2::task_group&, edm::Worker::RunModuleTask<edm::OccurrenceTraits<edm::EventPrincipal, (edm::TransitionActionType)1> >::execute()::{lambda()#1}&)::{lambda()#1}>::execute() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#11 0x000015189f329417 in tbb::detail::d2::function_task<edm::SerialTaskQueue::spawn(edm::SerialTaskQueue::TaskBase&)::{lambda()#1}>::execute(tbb::detail::d1::execution_data&) () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreConcurrency.so
#12 0x000015189f19f2f3 in tbb::detail::r1::task_dispatcher::local_wait_for_all<false, tbb::detail::r1::external_waiter> (waiter=..., t=0x15189c7dab00, this=<optimized out>) at src/tbb/task_dispatcher.h:344
#13 tbb::detail::r1::task_dispatcher::local_wait_for_all<tbb::detail::r1::external_waiter> (waiter=..., t=<optimized out>, this=<optimized out>) at src/tbb/task_dispatcher.h:487
#14 tbb::detail::r1::task_dispatcher::execute_and_wait (t=<optimized out>, wait_ctx=..., w_ctx=...) at src/tbb/task_dispatcher.cpp:169
#15 0x000015189ef4a97f in edm::FinalWaitingTask::wait() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#16 0x000015189ef5f7c9 in edm::EventProcessor::processRuns() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#17 0x000015189ef59571 in edm::EventProcessor::runToCompletion() () from /data/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_16_1_X_2026-02-10-1100/lib/el8_amd64_gcc13/libFWCoreFramework.so
#18 0x000000000040914d in tbb::detail::d1::task_arena_function<main::{lambda()#1}::operator()() const::{lambda()#1}, void>::operator()() const ()
#19 0x000015189f18e8c2 in tbb::detail::r1::task_arena_impl::execute (ta=..., d=...) at src/tbb/arena.cpp:860
#20 0x000000000040abf1 in main::{lambda()#1}::operator()() const ()
#21 0x0000000000405260 in main ()

Current Modules:

Module: Pythia8HepMC3GeneratorFilter:generator (crashed)

smuzaffar · 2026-02-10T21:31:24Z

please test using full cmssw for CMSSW_16_1_X/el8_amd64_gcc14

fwyzard · 2026-02-10T22:23:48Z

@makortel @fwyzard , any idea why building with cmssw -fimplicit-constexpr could have caused [a]

Without trying to investigate, the only thing I can think of is that some function is compiled as non-constexpr in the externals and as constexpr in CMSSW, and somehow that leads to some kind of conflict 🤷🏻‍♂️

smuzaffar · 2026-02-10T22:41:24Z

thanks @fwyzard , I also have read that we might have to rebuild full software stack with -fimplicit-constexpr to avoid any ODR violations

cmsbuild · 2026-02-11T08:09:49Z

-1

Failed Tests: UnitTests
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b353bf/51247/summary.html
COMMIT: e6d873d
CMSSW: CMSSW_16_1_X_2026-02-10-1100/el8_amd64_gcc14
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmsdist/10333/51247/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:

You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b353bf/51247/git-recent-commits.json
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b353bf/51247/git-merge-result

Failed Unit Tests

I found 5 errors in the following unit tests:

---> test test-particleLevel_fromHepMC3 had ERRORS
---> test test-rivet-run had ERRORS
---> test test-yoda-merge had ERRORS
and more ...

Comparison Summary

Summary:

You potentially removed 134 lines from the logs
Reco comparison results: 98802 differences found in the comparisons
DQMHistoTests: Total files compared: 52
DQMHistoTests: Total histograms compared: 4031484
DQMHistoTests: Total failures: 463031
DQMHistoTests: Total nulls: 237
DQMHistoTests: Total successes: 3568196
DQMHistoTests: Total skipped: 20
DQMHistoTests: Total Missing objects: 0
DQMHistoSizes: Histogram memory added: -5.840000000000001 KiB( 51 files compared)
DQMHistoSizes: changed ( 13034.0 ): 0.176 KiB SiStrip/MechanicalView
DQMHistoSizes: changed ( 17034.0,... ): -0.399 KiB SiStrip/MechanicalView
DQMHistoSizes: changed ( 2023.0020001 ): -0.004 KiB JetMET/SUSYDQM
DQMHistoSizes: changed ( 2024.0000001 ): -0.039 KiB JetMET/SUSYDQM
DQMHistoSizes: changed ( 2024.0010001,... ): 0.004 KiB JetMET/SUSYDQM
DQMHistoSizes: changed ( 2024.0050001 ): 0.035 KiB JetMET/SUSYDQM
DQMHistoSizes: changed ( 2024.0060001,... ): 0.008 KiB JetMET/SUSYDQM
DQMHistoSizes: changed ( 250202.181 ): 0.293 KiB SiStrip/MechanicalView
DQMHistoSizes: changed ( 25202.0 ): -0.308 KiB SiStrip/MechanicalView
DQMHistoSizes: changed ( 7.3 ): -5.219 KiB SiStrip/MechanicalView
Checked 222 log files, 193 edm output root files, 52 DQM output files
TriggerResults: found differences in 19 / 50 workflows

fwyzard · 2026-02-11T13:34:49Z

The good news: other than the unit tests CMSSW seems to work fine -- for example, I could run the full HLT menu.

The bad news: the -fimplicit-constexpr build does not show any speed improvement.

Benchmarking hlt.py with the reference release at /cvmfs/cms-ib.cern.ch/sw/x86_64/week0/el8_amd64_gcc14/cms/cmssw/CMSSW_16_1_X_2026-02-10-1100:

98.9 ± 0.6 ev/s

Benchmarking hlt.py with the local release at /scratch/constexpr/CMSSW_16_1_X_2026-02-10-1100:

99.0 ± 0.9 ev/s

Testing GCC with -fimplicit-constexpr

e6d873d

cmsbuild added externals-pending pending-signatures tests-started orp-pending labels Feb 10, 2026

smuzaffar changed the title ~~Testing GCC with -fimplicit-constexpr~~ Testing CMSSW build with -fimplicit-constexpr Feb 10, 2026

cmsbuild added tests-rejected and removed tests-started labels Feb 10, 2026

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Testing CMSSW build with -fimplicit-constexpr#10333

Testing CMSSW build with -fimplicit-constexpr#10333
smuzaffar wants to merge 1 commit intoIB/CMSSW_16_1_X/masterfrom
gcc-implicit-constexpr

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