CLANG 9 build errors

[smuzaffar]

With LLVM 9.0.1 we get a lot of build errors. [a] can be fixe easily in cmssw but for [b] I would suggest to add -Wno-tautological-type-limit-compare flag in llvm-cxxcompiler tool file.

[a]

      3 Alignment/MillePedeAlignmentAlgorithm/interface/MillePedeFileReader.h:172:48: error: result of comparison of unsigned enum expression < 0 is always false [-Werror,-Wtautological-unsigned-enum-zero-compare]
      6 EgammaAnalysis/ElectronTools/interface/EnergyScaleCorrection_class.h:195:15: error: result of comparison of unsigned enum expression >= 0 is always true [-Werror,-Wtautological-unsigned-enum-zero-compare]
      2 HLTrigger/JetMET/src/HLTJetSortedVBFFilter.cc:165:43: error: result of comparison of unsigned expression < 0 is always false [-Werror,-Wtautological-unsigned-zero-compare]
      1 RecoEgamma/EgammaTools/src/EnergyScaleCorrection.cc:174:13: error: result of comparison of unsigned enum expression >= 0 is always true [-Werror,-Wtautological-unsigned-enum-zero-compare]
      1 RecoTauTag/RecoTau/plugins/DPFIsolation.cc:171:24: error: result of comparison of unsigned enum expression < 0 is always false [-Werror,-Wtautological-unsigned-enum-zero-compare]

[b]

      1 Alignment/MillePedeAlignmentAlgorithm/plugins/MillePedeAlignmentAlgorithm.cc:816:42: error: result of comparison 'int' <= 2147483647 is always true [-Werror,-Wtautological-type-limit-compare]
      1 Alignment/MillePedeAlignmentAlgorithm/plugins/MillePedeAlignmentAlgorithm.cc:937:44: error: result of comparison 'int' <= 2147483647 is always true [-Werror,-Wtautological-type-limit-compare]
      1 IOMC/RandomEngine/src/RandomNumberGeneratorService.cc:165:35: error: result of comparison '__gnu_cxx::__alloc_traits<std::allocator<unsigned int>, unsigned int>::value_type' (aka 'unsigned int') > 4294967295 is always false [-Werror,-Wtautological-type-limit-compare]
      1 IOMC/RandomEngine/src/RandomNumberGeneratorService.cc:174:35: error: result of comparison '__gnu_cxx::__alloc_traits<std::allocator<unsigned int>, unsigned int>::value_type' (aka 'unsigned int') > 4294967295 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/DTTrackFinder/src/L1MuDTTrackSegPhi.cc:60:15: error: result of comparison 'L1MuDTTrackSegPhi::TSQuality' > 7 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/DTTrackFinder/src/L1MuDTTrackSegPhi.cc:74:15: error: result of comparison 'L1MuDTTrackSegPhi::TSQuality' > 7 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/L1TCalorimeter/src/firmware/Stage2Layer2EtSumAlgorithmFirmwareImp1.cc:205:22: error: result of comparison 'int' > 2147483647 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/L1TCalorimeter/src/firmware/Stage2Layer2EtSumAlgorithmFirmwareImp1.cc:207:22: error: result of comparison 'int' > 2147483647 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/L1TCalorimeter/src/firmware/Stage2Layer2EtSumAlgorithmFirmwareImp1.cc:209:26: error: result of comparison 'int' > 2147483647 is always false [-Werror,-Wtautological-type-limit-compare]
      1 L1Trigger/L1TCalorimeter/src/firmware/Stage2Layer2EtSumAlgorithmFirmwareImp1.cc:211:26: error: result of comparison 'int' > 2147483647 is always false [-Werror,-Wtautological-type-limit-compare]
      9 boost/iostreams/seek.hpp:112:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') < -9223372036854775808 is always false [-Werror,-Wtautological-type-limit-compare]
      9 boost/iostreams/seek.hpp:113:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') > 9223372036854775807 is always false [-Werror,-Wtautological-type-limit-compare]
      9 boost/iostreams/seek.hpp:85:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') < -9223372036854775808 is always false [-Werror,-Wtautological-type-limit-compare]
      9 boost/iostreams/seek.hpp:86:20: error: result of comparison 'boost::iostreams::stream_offset' (aka 'long') > 9223372036854775807 is always false [-Werror,-Wtautological-type-limit-compare]

[cmsbuild]

A new Issue was created by @smuzaffar Malik Shahzad Muzaffar.

@Dr15Jones, @smuzaffar, @silviodonato, @makortel, @davidlange6, @fabiocos can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[makortel]

assign core

[cmsbuild]

New categories assigned: core

@Dr15Jones,@smuzaffar,@makortel you have been requested to review this Pull request/Issue and eventually sign? Thanks

[makortel]

@smuzaffar Can those be turned to warnings instead of errors? (just thinking out loud options) Some of these look like possible logic errors or flaws.

On the other hand, we probably can't do much for boost/iostreams/seek.hpp... (and lot's of noise doesn't help either)

[smuzaffar]

@makortel , we can turn these to warnings but PR tests will then fail if someone touch these files (note that we mark PR tests failed if there are clang warnings )

[makortel]

Ok. I tend to agree that at least as a first step towards clang 9 the -Wno-tautological-type-limit-compare makes sense. We can then in parallel or later figure out if we want to enable this warning.

[smuzaffar]

+core
cmssw warnings/errors are now fix and cms-sw/cmsdist#5524 added the compilation flag -Wno-tautological-type-limit-compare

[cmsbuild]

This issue is fully signed and ready to be closed.