[CLANG] Fix compilation error with LLVM 9.0.1

[smuzaffar]

Fix compilation error [a] which we see while using LLVM 9.0.1

[a]

In file included from CMSSW_11_1_CLANG_X_2020-01-17-2300/src/SimTracker/TrackerHitAssociation/interface/TrackerHitAssociator.h:47:
  CMSSW_11_1_CLANG_X_2020-01-17-2300/src/DataFormats/TrackerRecHit2D/interface/FastTrackerRecHit.h:25:17: error: result of comparison of unsigned enum expression >= 0 is always true [-Werror,-Wtautological-unsigned-enum-zero-compare]
     if (hitType >= 0 && hitType <= 2)
        ~~~~~~~ ^  ~

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-28795/13480

• This PR adds an extra 8KB to repository

[cmsbuild]

A new Pull Request was created by @smuzaffar (Malik Shahzad Muzaffar) for master.

It involves the following packages:

DataFormats/TrackerRecHit2D

@perrotta, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@makortel, @gpetruc, @rovere, @VinInn this is something you requested to watch as well.
@davidlange6, @silviodonato, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[perrotta]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/4357/console Started: 2020/01/27 09:32

[cmsbuild]

+1
Tested at: e7a3d83
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-39c678/4357/summary.html
CMSSW: CMSSW_11_1_X_2020-01-26-2300
SCRAM_ARCH: slc7_amd64_gcc820

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-39c678/4357/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 34
• DQMHistoTests: Total histograms compared: 2697090
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2696743
• DQMHistoTests: Total skipped: 346
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 33 files compared)
• Checked 147 log files, 16 edm output root files, 34 DQM output files

[perrotta]

+1

• Trivial fix
• Jenkins tests pass

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @davidlange6, @silviodonato, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[makortel]

So comparing to literal 0 is bad, but comparing to siPixel that has a value 0 is fine? I mean, hitType >= siPixel is still a tautology assuming the caller passes only valid HitType values.

(I'm not objecting the proposed fix, just wondering out loud)

[smuzaffar]

yes @makortel , at least llvm does not complain any more. May be the check should be change to

if (hitType <= siStrip2D)
or
if (hitType <= 2)

[silviodonato]

I agree this behavior looks a bit weird. However, since LLVM does not complain anymore, I would keep if (hitType >= siPixel && hitType <= siStrip2D). It seems more clear to me.

[silviodonato]

+1