cms-sw · smuzaffar · Nov 26, 2025
diff --git a/DataFormats/L1GlobalTrigger/src/L1GtfeExtWord.cc b/DataFormats/L1GlobalTrigger/src/L1GtfeExtWord.cc
@@ -73,7 +73,7 @@ L1GtfeExtWord::~L1GtfeExtWord() {
 bool L1GtfeExtWord::operator==(const L1GtfeExtWord& result) const {
   // base class
 
-  const L1GtfeWord gtfeResult = result;
+  const L1GtfeWord& gtfeResult = result;
   const L1GtfeWord gtfeThis = *this;
 
   if (gtfeThis != gtfeResult) {

diff --git a/EventFilter/L1TRawToDigi/plugins/OmtfUnpacker.cc b/EventFilter/L1TRawToDigi/plugins/OmtfUnpacker.cc
@@ -281,7 +281,7 @@ namespace omtf {
       // loop over AMC's
       //
       unsigned int blockNum = 0;
-      for (auto amc : packetAmc13.payload()) {
+      for (const auto& amc : packetAmc13.payload()) {
         amc::BlockHeader bh = amc.blockHeader();
         if (debug) {
           std::ostringstream str;

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockCounters.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockCounters.cc
@@ -32,7 +32,7 @@ namespace l1t {
     namespace emtf {
 
       int CountersBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         //Check the number of 16-bit words
@@ -91,7 +91,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Check Format of Payload
         l1t::emtf::Counters Counters_;

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockGEM.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockGEM.cc
@@ -31,7 +31,7 @@ namespace l1t {
     namespace emtf {
 
       int GEMBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         // Check the number of 16-bit words
@@ -125,7 +125,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Run 3 has a different EMTF DAQ output format since August 26th
         // Computed as (Year - 2000)*2^9 + Month*2^5 + Day (see Block.cc and EMTFBlockTrailers.cc)

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockHeaders.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockHeaders.cc
@@ -32,7 +32,7 @@ namespace l1t {
     namespace emtf {
 
       int HeadersBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         //Check the number of 16-bit words
@@ -163,7 +163,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Check Format of Payload
         l1t::emtf::AMC13Header AMC13Header_;

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockME.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockME.cc
@@ -32,7 +32,7 @@ namespace l1t {
     namespace emtf {
 
       int MEBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         // Check the number of 16-bit words
@@ -151,7 +151,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Assign payload to 16-bit words
         uint16_t MEa = payload[0];

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockRPC.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockRPC.cc
@@ -33,7 +33,7 @@ namespace l1t {
     namespace emtf {
 
       int RPCBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         // Check the number of 16-bit words
@@ -119,7 +119,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Run 3 has a different EMTF DAQ output format since August 26th
         // Computed as (Year - 2000)*2^9 + Month*2^5 + Day (see Block.cc and EMTFBlockTrailers.cc)

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockSP.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockSP.cc
@@ -32,7 +32,7 @@ namespace l1t {
     namespace emtf {
 
       int SPBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         // Check the number of 16-bit words
@@ -174,7 +174,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // FW version is computed as (Year - 2000)*2^9 + Month*2^5 + Day (see Block.cc and EMTFBlockTrailers.cc)
         bool useNNBits_ = getAlgoVersion() >= 11098;   // FW versions >= 26.10.2021

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockTrailers.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/EMTFBlockTrailers.cc
@@ -32,7 +32,7 @@ namespace l1t {
     namespace emtf {
 
       int TrailersBlockUnpacker::checkFormat(const Block& block) {
-        auto payload = block.payload();
+        const auto& payload = block.payload();
         int errors = 0;
 
         //Check the number of 16-bit words
@@ -128,7 +128,7 @@ namespace l1t {
         // Get the payload for this block, made up of 16-bit words (0xffff)
         // Format defined in MTF7Payload::getBlock() in src/Block.cc
         // payload[0] = bits 0-15, payload[1] = 16-31, payload[3] = 32-47, etc.
-        auto payload = block.payload();
+        const auto& payload = block.payload();
 
         // Check Format of Payload
         l1t::emtf::AMC13Trailer AMC13Trailer_;

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/IntermediateMuonUnpacker.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/IntermediateMuonUnpacker.cc
@@ -19,7 +19,7 @@ namespace l1t {
         return true;
       }
 
-      auto payload = block.payload();
+      const auto& payload = block.payload();
 
       int nBX, firstBX, lastBX;
       // Check if per BX zero suppression was enabled

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/MuonUnpacker.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/MuonUnpacker.cc
@@ -18,7 +18,7 @@ namespace l1t {
         return true;
       }
 
-      auto payload = block.payload();
+      const auto& payload = block.payload();
 
       int nBX, firstBX, lastBX;
       // Check if per BX zero suppression was enabled

diff --git a/EventFilter/L1TRawToDigi/plugins/implementations_stage2/RegionalMuonGMTUnpacker.cc b/EventFilter/L1TRawToDigi/plugins/implementations_stage2/RegionalMuonGMTUnpacker.cc
@@ -16,7 +16,7 @@ namespace l1t {
         return true;
       }
 
-      auto payload = block.payload();
+      const auto& payload = block.payload();
 
       int nBX, firstBX, lastBX;
       // Check if per BX zero suppression was enabled

diff --git a/EventFilter/L1TRawToDigi/src/AMC13Spec.cc b/EventFilter/L1TRawToDigi/src/AMC13Spec.cc
@@ -141,6 +141,7 @@ namespace amc13 {
       Header block_h(data++);
       std::vector<amc::BlockHeader> headers;
 
+      headers.reserve(block_h.getNumberOfAMCs());
       for (unsigned int i = 0; i < block_h.getNumberOfAMCs(); ++i)
         headers.push_back(amc::BlockHeader(data++));
 

diff --git a/L1Trigger/CSCTriggerPrimitives/src/CSCGEMMatcher.cc b/L1Trigger/CSCTriggerPrimitives/src/CSCGEMMatcher.cc
@@ -277,7 +277,7 @@ uint16_t CSCGEMMatcher::mitigatedSlopeByConsistency(const CSCCLCTDigi& clct,
   const bool isME1a(station_ == 1 and clct.getKeyStrip() > CSCConstants::MAX_HALF_STRIP_ME1B);
 
   // extract hit values from CLCT hit matrix
-  std::vector<std::vector<uint16_t>> CLCTHitMatrix = clct.getHits();
+  const std::vector<std::vector<uint16_t>>& CLCTHitMatrix = clct.getHits();
   int CLCTHits[6] = {-1, -1, -1, -1, -1, -1};
 
   for (unsigned layer = 0; layer < CLCTHitMatrix.size(); ++layer) {

diff --git a/L1Trigger/DTTriggerPhase2/src/LateralityCoarsedProvider.cc b/L1Trigger/DTTriggerPhase2/src/LateralityCoarsedProvider.cc
@@ -249,6 +249,7 @@ std::vector<std::vector<short>> LateralityCoarsedProvider::convertString(std::st
 
   for (size_t i = 0; i < chain.size(); i += 4) {
     std::vector<short> group;
+    group.reserve(4);
     for (size_t j = 0; j < 4; j++) {
       group.push_back(chain[i + j] - '0');  // Convert the character to integer
     }

diff --git a/L1Trigger/DTTriggerPhase2/src/MuonPathCorFitter.cc b/L1Trigger/DTTriggerPhase2/src/MuonPathCorFitter.cc
@@ -407,6 +407,7 @@ void MuonPathCorFitter::fillLuts() {
     ifin2sl >> line;
 
     std::vector<int> myNumbers;
+    myNumbers.reserve(line.size());
     for (size_t i = 0; i < line.size(); i++) {
       // This converts the char into an int and pushes it into vec
       myNumbers.push_back(line[i] - '0');  // The digits will be in the same order as before

diff --git a/L1Trigger/DTTriggerPhase2/src/MuonPathSLFitter.cc b/L1Trigger/DTTriggerPhase2/src/MuonPathSLFitter.cc
@@ -68,7 +68,7 @@ void MuonPathSLFitter::run(edm::Event &iEvent,
   // fit per SL (need to allow for multiple outputs for a single mpath)
   // for (auto &muonpath : muonpaths) {
   if (!muonpaths.empty()) {
-    auto muonpath = muonpaths[0];
+    const auto &muonpath = muonpaths[0];
     int rawId = muonpath->primitive(0)->cameraId();
     if (muonpath->primitive(0)->cameraId() == -1) {
       rawId = muonpath->primitive(1)->cameraId();
@@ -79,7 +79,7 @@ void MuonPathSLFitter::run(edm::Event &iEvent,
 
   for (size_t i = 0; i < muonpaths.size(); i++) {
     auto muonpath = muonpaths[i];
-    auto lats = lateralities[i];
+    const auto &lats = lateralities[i];
     analyze(muonpath, lats, metaPrimitives);
   }
 }
@@ -448,6 +448,7 @@ void MuonPathSLFitter::fillLuts() {
     ifinsl1 >> line;
 
     std::vector<int> myNumbers;
+    myNumbers.reserve(line.size());
     for (size_t i = 0; i < line.size(); i++) {
       // This converts the char into an int and pushes it into vec
       myNumbers.push_back(line[i] - '0');  // The digits will be in the same order as before
@@ -461,6 +462,7 @@ void MuonPathSLFitter::fillLuts() {
     ifinsl2 >> line;
 
     std::vector<int> myNumbers;
+    myNumbers.reserve(line.size());
     for (size_t i = 0; i < line.size(); i++) {
       // This converts the char into an int and pushes it into vec
       myNumbers.push_back(line[i] - '0');  // The digits will be in the same order as before
@@ -474,6 +476,7 @@ void MuonPathSLFitter::fillLuts() {
     ifinsl3 >> line;
 
     std::vector<int> myNumbers;
+    myNumbers.reserve(line.size());
     for (size_t i = 0; i < line.size(); i++) {
       // This converts the char into an int and pushes it into vec
       myNumbers.push_back(line[i] - '0');  // The digits will be in the same order as before

diff --git a/L1Trigger/L1CaloTrigger/plugins/L1NNCaloTauEmulator.cc b/L1Trigger/L1CaloTrigger/plugins/L1NNCaloTauEmulator.cc
@@ -789,7 +789,7 @@ void L1NNCaloTauEmulator::produce(edm::Event& iEvent, const edm::EventSetup& eSe
 
   for (int clNxMIdx = 0; clNxMIdx < Nclusters_CE; clNxMIdx++) {
     // Indexing of cl3ds is the same as the one of clNxMs
-    InputHGCluster HGClu = HGClusters[clNxMIdx];
+    const InputHGCluster& HGClu = HGClusters[clNxMIdx];
 
     // Fill inputs for Tensorflow inference
     for (int eta = 0; eta < IEta_dim; ++eta) {

diff --git a/L1Trigger/L1TCaloLayer1/src/L1TCaloLayer1FetchLUTs.cc b/L1Trigger/L1TCaloLayer1/src/L1TCaloLayer1FetchLUTs.cc
@@ -27,15 +27,15 @@
 using namespace l1tcalo;
 
 bool L1TCaloLayer1FetchLUTs(
-    const L1TCaloLayer1FetchLUTsTokens &iTokens,
-    const edm::EventSetup &iSetup,
-    std::vector<std::array<std::array<std::array<uint32_t, nEtBins>, nCalSideBins>, nCalEtaBins> > &eLUT,
-    std::vector<std::array<std::array<std::array<uint32_t, nEtBins>, nCalSideBins>, nCalEtaBins> > &hLUT,
-    std::vector<std::array<std::array<uint32_t, nEtBins>, nHfEtaBins> > &hfLUT,
-    std::vector<unsigned long long int> &hcalFBLUT,
-    std::vector<unsigned int> &ePhiMap,
-    std::vector<unsigned int> &hPhiMap,
-    std::vector<unsigned int> &hfPhiMap,
+    const L1TCaloLayer1FetchLUTsTokens& iTokens,
+    const edm::EventSetup& iSetup,
+    std::vector<std::array<std::array<std::array<uint32_t, nEtBins>, nCalSideBins>, nCalEtaBins> >& eLUT,
+    std::vector<std::array<std::array<std::array<uint32_t, nEtBins>, nCalSideBins>, nCalEtaBins> >& hLUT,
+    std::vector<std::array<std::array<uint32_t, nEtBins>, nHfEtaBins> >& hfLUT,
+    std::vector<unsigned long long int>& hcalFBLUT,
+    std::vector<unsigned int>& ePhiMap,
+    std::vector<unsigned int>& hPhiMap,
+    std::vector<unsigned int>& hfPhiMap,
     bool useLSB,
     bool useCalib,
     bool useECALLUT,
@@ -44,7 +44,7 @@ bool L1TCaloLayer1FetchLUTs(
     bool useHCALFBLUT,
     int fwVersion) {
   int hfValid = 1;
-  const HcalTrigTowerGeometry &pG = iSetup.getData(iTokens.geom_);
+  const HcalTrigTowerGeometry& pG = iSetup.getData(iTokens.geom_);
   if (!pG.use1x1()) {
     edm::LogError("L1TCaloLayer1FetchLUTs")
         << "Using Stage2-Layer1 but HCAL Geometry has use1x1 = 0! HF will be suppressed.  Check Global Tag, etc.";
@@ -71,7 +71,7 @@ bool L1TCaloLayer1FetchLUTs(
   //   etBin = size of Real ET Bins vector
   //   phiBin = max(Real Phi Bins vector)
   //   So, index = phiBin*etBin*28+etBin*28+ieta
-  auto ecalScaleETBins = caloParams.layer1ECalScaleETBins();
+  const auto& ecalScaleETBins = caloParams.layer1ECalScaleETBins();
   auto ecalScalePhiBins = caloParams.layer1ECalScalePhiBins();
   if (ecalScalePhiBins.empty()) {
     // Backwards-compatibility (no phi binning)
@@ -81,14 +81,14 @@ bool L1TCaloLayer1FetchLUTs(
     return false;
   }
   size_t numEcalPhiBins = (*std::max_element(ecalScalePhiBins.begin(), ecalScalePhiBins.end())) + 1;
-  auto ecalSF = caloParams.layer1ECalScaleFactors();
-  auto ecalZSF = caloParams.layer1ECalZSFactors();
+  const auto& ecalSF = caloParams.layer1ECalScaleFactors();
+  const auto& ecalZSF = caloParams.layer1ECalZSFactors();
   if (ecalSF.size() != ecalScaleETBins.size() * numEcalPhiBins * 28) {
     edm::LogError("L1TCaloLayer1FetchLUTs") << "caloParams.layer1ECalScaleFactors().size() != "
                                                "caloParams.layer1ECalScaleETBins().size()*numEcalPhiBins*28 !!";
     return false;
   }
-  auto hcalScaleETBins = caloParams.layer1HCalScaleETBins();
+  const auto& hcalScaleETBins = caloParams.layer1HCalScaleETBins();
   auto hcalScalePhiBins = caloParams.layer1HCalScalePhiBins();
   if (hcalScalePhiBins.empty()) {
     hcalScalePhiBins.resize(36, 0);
@@ -97,8 +97,8 @@ bool L1TCaloLayer1FetchLUTs(
     return false;
   }
   size_t numHcalPhiBins = (*std::max_element(hcalScalePhiBins.begin(), hcalScalePhiBins.end())) + 1;
-  auto hcalSF = caloParams.layer1HCalScaleFactors();
-  auto hcalZSF = caloParams.layer1HCalZSFactors();
+  const auto& hcalSF = caloParams.layer1HCalScaleFactors();
+  const auto& hcalZSF = caloParams.layer1HCalZSFactors();
   if (hcalSF.size() != hcalScaleETBins.size() * numHcalPhiBins * 28) {
     edm::LogError("L1TCaloLayer1FetchLUTs") << "caloParams.layer1HCalScaleFactors().size() != "
                                                "caloParams.layer1HCalScaleETBins().size()*numHcalPhiBins*28 !!";
@@ -110,7 +110,7 @@ bool L1TCaloLayer1FetchLUTs(
   //   etBin = size of Real ET Bins vector
   //   phiBin = max(Real Phi Bins vector)
   //   So, index = phiBin*etBin*12+etBin*12+ieta
-  auto hfScaleETBins = caloParams.layer1HFScaleETBins();
+  const auto& hfScaleETBins = caloParams.layer1HFScaleETBins();
   auto hfScalePhiBins = caloParams.layer1HFScalePhiBins();
   if (hfScalePhiBins.empty()) {
     hfScalePhiBins.resize(36, 0);
@@ -119,7 +119,7 @@ bool L1TCaloLayer1FetchLUTs(
     return false;
   }
   size_t numHFPhiBins = (*std::max_element(hfScalePhiBins.begin(), hfScalePhiBins.end())) + 1;
-  auto hfSF = caloParams.layer1HFScaleFactors();
+  const auto& hfSF = caloParams.layer1HFScaleFactors();
   if (hfSF.size() != hfScaleETBins.size() * numHFPhiBins * 12) {
     edm::LogError("L1TCaloLayer1FetchLUTs")
         << "caloParams.layer1HFScaleFactors().size() != caloParams.layer1HFScaleETBins().size()*numHFPhiBins*12 !!";
@@ -136,8 +136,8 @@ bool L1TCaloLayer1FetchLUTs(
   // HCAL FB LUT will be a 1*28 array:
   //   ieta = 28 eta scale factors (1 .. 28)
   //   So, index = ieta
-  auto fbLUTUpper = caloParams.layer1HCalFBLUTUpper();
-  auto fbLUTLower = caloParams.layer1HCalFBLUTLower();
+  const auto& fbLUTUpper = caloParams.layer1HCalFBLUTUpper();
+  const auto& fbLUTLower = caloParams.layer1HCalFBLUTLower();
   // Only check for HCAL FB LUT if useHCALFBLUT = true
   if (useHCALFBLUT) {
     if (fbLUTUpper.size() != nCalEtaBins) {

diff --git a/L1Trigger/L1TCalorimeter/src/HardwareSortingMethods.cc b/L1Trigger/L1TCalorimeter/src/HardwareSortingMethods.cc
@@ -544,8 +544,8 @@ namespace l1t {
         super_sort_matrix_rows(non_iso_stage2_row_sorted_matrix_sig, N_EGAMMA_SECOND_GROUP_SIZE, N_KEEP_EGAMMA);
 
     //Prepare output
-    std::vector<l1t::L1Candidate> sorted_iso_egammas = iso_stage2_super_sorted_matrix_sig[0];
-    std::vector<l1t::L1Candidate> sorted_noniso_egammas = non_iso_stage2_super_sorted_matrix_sig[0];
+    const std::vector<l1t::L1Candidate>& sorted_iso_egammas = iso_stage2_super_sorted_matrix_sig[0];
+    const std::vector<l1t::L1Candidate>& sorted_noniso_egammas = non_iso_stage2_super_sorted_matrix_sig[0];
 
     //verbose = false;
 

diff --git a/L1Trigger/L1TCalorimeter/src/PUSubtractionMethods.cc b/L1Trigger/L1TCalorimeter/src/PUSubtractionMethods.cc
@@ -69,7 +69,7 @@ namespace l1t {
   void RegionCorrection(const std::vector<l1t::CaloRegion> &regions,
                         std::vector<l1t::CaloRegion> *subRegions,
                         CaloParamsHelper const *params) {
-    std::string regionPUSType = params->regionPUSType();
+    const std::string &regionPUSType = params->regionPUSType();
 
     if (regionPUSType == "None") {
       for (std::vector<CaloRegion>::const_iterator notCorrectedRegion = regions.begin();

diff --git a/L1Trigger/L1TGEM/src/ME0StubAlgoPatUnit.cc b/L1Trigger/L1TGEM/src/ME0StubAlgoPatUnit.cc
@@ -17,7 +17,7 @@ std::pair<std::vector<double>, double> l1t::me0::calculateCentroids(
   std::vector<int> bxs;
   for (int ly = 0; ly < static_cast<int>(maskedData.size()); ++ly) {
     auto data = maskedData[ly];
-    auto bxData = partitionBxData[ly];
+    const auto& bxData = partitionBxData[ly];
     const auto temp = findCentroid(data);
     double curCentroid = temp.first;
     std::vector<int> hitsIndices = temp.second;
@@ -199,4 +199,4 @@ ME0StubPrimitive l1t::me0::patUnit(const std::vector<uint64_t>& data,
   best.updateQuality();
 
   return best;
-}
+}
diff --git a/L1Trigger/L1TGlobal/plugins/L1TGlobalPrescalesVetosESProducer.cc b/L1Trigger/L1TGlobal/plugins/L1TGlobalPrescalesVetosESProducer.cc
@@ -237,6 +237,7 @@ L1TGlobalPrescalesVetosESProducer::L1TGlobalPrescalesVetosESProducer(const edm::
 
   // veto mask
   // Setting veto mask to default 0 (no veto)
+  triggerVetoMasks.reserve(m_numberPhysTriggers);
   for (unsigned int iAlg = 0; iAlg < m_numberPhysTriggers; iAlg++)
     triggerVetoMasks.push_back(0);