diff --git a/applications/solvers/multiphase/icoReactingMultiphaseInterFoam/laserDTRM/laserDTRM.C b/applications/solvers/multiphase/icoReactingMultiphaseInterFoam/laserDTRM/laserDTRM.C
index 4d9e61e8e1..422b4d364d 100644
--- a/applications/solvers/multiphase/icoReactingMultiphaseInterFoam/laserDTRM/laserDTRM.C
+++ b/applications/solvers/multiphase/icoReactingMultiphaseInterFoam/laserDTRM/laserDTRM.C
@@ -157,12 +157,7 @@ void Foam::radiation::laserDTRM::initialiseReflection()
             );
         }
 
-        if (reflections_.size())
-        {
-            reflectionSwitch_ = true;
-        }
-
-        reflectionSwitch_ = returnReduce(reflectionSwitch_, orOp<bool>());
+        reflectionSwitch_ = returnReduceOr(reflections_.size());
     }
 }
 
@@ -299,14 +294,12 @@ void Foam::radiation::laserDTRM::initialise()
                     DTRMCloud_.addParticle(pPtr);
                 }
 
-                if (returnReduce(cellI, maxOp<label>()) == -1)
+                if (nMissed < 10 && returnReduceAnd(cellI < 0))
                 {
-                    if (++nMissed <= 10)
-                    {
-                        WarningInFunction
-                            << "Cannot find owner cell for focalPoint at "
-                            << p0 << endl;
-                    }
+                    ++nMissed;
+                    WarningInFunction
+                        << "Cannot find owner cell for focalPoint at "
+                        << p0 << endl;
                 }
             }
         }
diff --git a/applications/test/GAMGAgglomeration/Test-GAMGAgglomeration.C b/applications/test/GAMGAgglomeration/Test-GAMGAgglomeration.C
index a02077550d..cf5584e01f 100644
--- a/applications/test/GAMGAgglomeration/Test-GAMGAgglomeration.C
+++ b/applications/test/GAMGAgglomeration/Test-GAMGAgglomeration.C
@@ -113,7 +113,6 @@ int main(int argc, char *argv[])
         label coarseSize = max(addr)+1;
 
         Info<< "Level : " << level << endl
-            << returnReduce(addr.size(), sumOp<label>()) << endl
             << "    current size      : "
             << returnReduce(addr.size(), sumOp<label>()) << endl
             << "    agglomerated size : "
diff --git a/applications/utilities/mesh/advanced/PDRMesh/PDRMesh.C b/applications/utilities/mesh/advanced/PDRMesh/PDRMesh.C
index 6f4cf9b64e..b3ec7e2fd7 100644
--- a/applications/utilities/mesh/advanced/PDRMesh/PDRMesh.C
+++ b/applications/utilities/mesh/advanced/PDRMesh/PDRMesh.C
@@ -585,7 +585,7 @@ void createBaffles
 // Wrapper around find patch. Also makes sure same patch in parallel.
 label findPatch(const polyBoundaryMesh& patches, const word& patchName)
 {
-    label patchi = patches.findPatchID(patchName);
+    const label patchi = patches.findPatchID(patchName);
 
     if (patchi == -1)
     {
@@ -597,16 +597,15 @@ label findPatch(const polyBoundaryMesh& patches, const word& patchName)
 
     // Check same patch for all procs
     {
-        label newPatch = patchi;
-        reduce(newPatch, minOp<label>());
+        const label newPatchi = returnReduce(patchi, minOp<label>());
 
-        if (newPatch != patchi)
+        if (newPatchi != patchi)
         {
             FatalErrorInFunction
                 << "Patch " << patchName
                 << " should have the same patch index on all processors." << nl
                 << "On my processor it has index " << patchi
-                << " ; on some other processor it has index " << newPatch
+                << " ; on some other processor it has index " << newPatchi
                 << exit(FatalError);
         }
     }
diff --git a/applications/utilities/mesh/advanced/selectCells/selectCells.C b/applications/utilities/mesh/advanced/selectCells/selectCells.C
index 04455a8489..c42031d778 100644
--- a/applications/utilities/mesh/advanced/selectCells/selectCells.C
+++ b/applications/utilities/mesh/advanced/selectCells/selectCells.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -396,12 +397,11 @@ int main(int argc, char *argv[])
     meshSearch queryMesh(mesh);
 
     // Check all 'outside' points
-    forAll(outsidePts, outsideI)
+    for (const point& outsidePoint : outsidePts)
     {
-        const point& outsidePoint = outsidePts[outsideI];
+        const label celli = queryMesh.findCell(outsidePoint, -1, false);
 
-        label celli = queryMesh.findCell(outsidePoint, -1, false);
-        if (returnReduce(celli, maxOp<label>()) == -1)
+        if (returnReduceAnd(celli < 0))
         {
             FatalErrorInFunction
                 << "outsidePoint " << outsidePoint
diff --git a/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C b/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
index f93e6f03af..cd84e849cc 100644
--- a/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
+++ b/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
@@ -538,8 +538,11 @@ int main(int argc, char *argv[])
 
         // Add any patches.
 
-        label nAdded = nPatches - mesh.boundaryMesh().size();
-        reduce(nAdded, sumOp<label>());
+        const label nAdded = returnReduce
+        (
+            nPatches - mesh.boundaryMesh().size(),
+            sumOp<label>()
+        );
 
         Info<< "Adding overall " << nAdded << " processor patches." << endl;
 
@@ -946,9 +949,8 @@ int main(int argc, char *argv[])
 
         // Put all modifications into meshMod
         bool anyChange = collapser.setRefinement(allPointInfo, meshMod);
-        reduce(anyChange, orOp<bool>());
 
-        if (anyChange)
+        if (returnReduceOr(anyChange))
         {
             // Construct new mesh from polyTopoChange.
             autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
@@ -1118,8 +1120,7 @@ int main(int argc, char *argv[])
     processorMeshes::removeFiles(mesh);
 
     // Need writing cellSet
-    label nAdded = returnReduce(addedCellsSet.size(), sumOp<label>());
-    if (nAdded > 0)
+    if (returnReduceOr(addedCellsSet.size()))
     {
         cellSet addedCells(mesh, "addedCells", addedCellsSet);
         Info<< "Writing added cells to cellSet " << addedCells.name()
diff --git a/applications/utilities/mesh/generation/extrude/extrudeToRegionMesh/extrudeToRegionMesh.C b/applications/utilities/mesh/generation/extrude/extrudeToRegionMesh/extrudeToRegionMesh.C
index e6854ac097..154cc796cb 100644
--- a/applications/utilities/mesh/generation/extrude/extrudeToRegionMesh/extrudeToRegionMesh.C
+++ b/applications/utilities/mesh/generation/extrude/extrudeToRegionMesh/extrudeToRegionMesh.C
@@ -345,7 +345,7 @@ void deleteEmptyPatches(fvMesh& mesh)
             else
             {
                 // Common patch.
-                if (returnReduce(patches[patchi].empty(), andOp<bool>()))
+                if (returnReduceAnd(patches[patchi].empty()))
                 {
                     Pout<< "Deleting patch " << patchi
                         << " name:" << patches[patchi].name()
diff --git a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/DelaunayMesh/DistributedDelaunayMesh.C b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/DelaunayMesh/DistributedDelaunayMesh.C
index b51546a528..ad263e559e 100644
--- a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/DelaunayMesh/DistributedDelaunayMesh.C
+++ b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/DelaunayMesh/DistributedDelaunayMesh.C
@@ -588,9 +588,8 @@ Foam::label Foam::DistributedDelaunayMesh<Triangulation>::referVertices
     reduce(preInsertionSize, sumOp<label>());
     reduce(postInsertionSize, sumOp<label>());
 
-    label nTotalToInsert = referredVertices.size();
-
-    reduce(nTotalToInsert, sumOp<label>());
+    label nTotalToInsert =
+        returnReduce(referredVertices.size(), sumOp<label>());
 
     if (preInsertionSize + nTotalToInsert != postInsertionSize)
     {
diff --git a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/backgroundMeshDecomposition/backgroundMeshDecomposition.C b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/backgroundMeshDecomposition/backgroundMeshDecomposition.C
index 796dfd807a..0aebe1fd4a 100644
--- a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/backgroundMeshDecomposition/backgroundMeshDecomposition.C
+++ b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/backgroundMeshDecomposition/backgroundMeshDecomposition.C
@@ -217,7 +217,7 @@ void Foam::backgroundMeshDecomposition::initialRefinement()
                     );
                 }
 
-                if (returnReduce(newCellsToRefine.size(), sumOp<label>()) == 0)
+                if (returnReduceAnd(newCellsToRefine.empty()))
                 {
                     break;
                 }
@@ -878,7 +878,7 @@ Foam::backgroundMeshDecomposition::distribute
             }
         }
 
-        if (returnReduce(cellsToRefine.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(cellsToRefine.empty()))
         {
             break;
         }
diff --git a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMesh.C b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMesh.C
index 5c93903644..996a9e2e13 100644
--- a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMesh.C
+++ b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMesh.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2016 OpenFOAM Foundation
-    Copyright (C) 2020-2021 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -87,23 +87,17 @@ void Foam::conformalVoronoiMesh::cellSizeMeshOverlapsBackground() const
 
     boundBox cellSizeMeshBb = cellSizeMesh.bounds();
 
-    bool fullyContained = true;
+    bool fullyContained = cellSizeMeshBb.contains(bb);
 
-    if (!cellSizeMeshBb.contains(bb))
+    if (!fullyContained)
     {
-        Pout<< "Triangulation not fully contained in cell size mesh."
-            << endl;
-
-        Pout<< "Cell Size Mesh Bounds = " << cellSizeMesh.bounds() << endl;
-        Pout<< "foamyHexMesh Bounds         = " << bb << endl;
-
-        fullyContained = false;
+        Pout<< "Triangulation not fully contained in cell size mesh." << endl
+            << "Cell Size Mesh Bounds = " << cellSizeMeshBb << endl
+            << "foamyHexMesh Bounds         = " << bb << endl;
     }
 
-    reduce(fullyContained, andOp<unsigned int>());
-
     Info<< "Triangulation is "
-        << (fullyContained ? "fully" : "not fully")
+        << (returnReduceAnd(fullyContained) ? "fully" : "not fully")
         << " contained in the cell size mesh"
         << endl;
 }
@@ -115,12 +109,7 @@ void Foam::conformalVoronoiMesh::insertInternalPoints
     bool distribute
 )
 {
-    label nPoints = points.size();
-
-    if (Pstream::parRun())
-    {
-        reduce(nPoints, sumOp<label>());
-    }
+    const label nPoints = returnReduce(points.size(), sumOp<label>());
 
     Info<< "    " << nPoints << " points to insert..." << endl;
 
@@ -145,16 +134,15 @@ void Foam::conformalVoronoiMesh::insertInternalPoints
         map().distribute(points);
     }
 
-    label nVert = number_of_vertices();
+    label preReinsertionSize(number_of_vertices());
 
     insert(points.begin(), points.end());
 
-    label nInserted(number_of_vertices() - nVert);
-
-    if (Pstream::parRun())
-    {
-        reduce(nInserted, sumOp<label>());
-    }
+    const label nInserted = returnReduce
+    (
+        label(number_of_vertices()) - preReinsertionSize,
+        sumOp<label>()
+    );
 
     Info<< "    " << nInserted << " points inserted"
         << ", failed to insert " << nPoints - nInserted
diff --git a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshCalcDualMesh.C b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshCalcDualMesh.C
index 567b8a5f1a..1c0a115919 100644
--- a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshCalcDualMesh.C
+++ b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshCalcDualMesh.C
@@ -753,7 +753,7 @@ Foam::conformalVoronoiMesh::createPolyMeshFromPoints
 
     forAll(patches, p)
     {
-        label totalPatchSize = patchDicts[p].get<label>("nFaces");
+        label nPatchFaces = patchDicts[p].get<label>("nFaces");
 
         if
         (
@@ -762,7 +762,7 @@ Foam::conformalVoronoiMesh::createPolyMeshFromPoints
         )
         {
             // Do not create empty processor patches
-            if (totalPatchSize > 0)
+            if (nPatchFaces)
             {
                 patchDicts[p].set("transform", "coincidentFullMatch");
 
@@ -781,9 +781,8 @@ Foam::conformalVoronoiMesh::createPolyMeshFromPoints
         else
         {
             // Check that the patch is not empty on every processor
-            reduce(totalPatchSize, sumOp<label>());
 
-            if (totalPatchSize > 0)
+            if (returnReduceOr(nPatchFaces))
             {
                 patches[nValidPatches] = polyPatch::New
                 (
diff --git a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
index f735e02833..150262b2aa 100644
--- a/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
+++ b/applications/utilities/mesh/generation/foamyMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2018 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -707,9 +707,7 @@ void Foam::conformalVoronoiMesh::reorderProcessorPatches
 
     Info<< incrIndent << indent << "Faces matched." << endl;
 
-    reduce(anyChanged, orOp<bool>());
-
-    if (anyChanged)
+    if (returnReduceOr(anyChanged))
     {
         label nReorderedFaces = 0;
 
diff --git a/applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C b/applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C
index 28242fdf14..ed93bc7f4e 100644
--- a/applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C
+++ b/applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C
@@ -665,7 +665,7 @@ void removeZeroSizedPatches(fvMesh& mesh)
             if
             (
                 isA<coupledPolyPatch>(pp)
-             || returnReduce(pp.size(), sumOp<label>())
+             || returnReduceOr(pp.size())
             )
             {
                 // Coupled (and unknown size) or uncoupled and used
@@ -1891,11 +1891,8 @@ int main(int argc, char *argv[])
         );
 
         // Use the maxLocalCells from the refinement parameters
-        bool preBalance = returnReduce
-        (
-            (mesh.nCells() >= refineParams.maxLocalCells()),
-            orOp<bool>()
-        );
+        const bool preBalance =
+            returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells());
 
 
         if (!overwrite && !debugLevel)
diff --git a/applications/utilities/mesh/manipulation/checkMesh/checkTopology.C b/applications/utilities/mesh/manipulation/checkMesh/checkTopology.C
index da07bf76ce..8aa4e36325 100644
--- a/applications/utilities/mesh/manipulation/checkMesh/checkTopology.C
+++ b/applications/utilities/mesh/manipulation/checkMesh/checkTopology.C
@@ -187,7 +187,7 @@ void Foam::checkPatch
     {
         const labelList& mp = pp.meshPoints();
 
-        if (returnReduce(mp.size(), sumOp<label>()) > 0)
+        if (returnReduceOr(mp.size()))
         {
             boundBox bb(pp.points(), mp, true); // reduce
             Info<< ' ' << bb;
@@ -252,10 +252,10 @@ Foam::label Foam::checkTopology
             }
         }
         reduce(nEmpty, sumOp<label>());
-        label nTotCells = returnReduce(mesh.cells().size(), sumOp<label>());
+        const label nCells = returnReduce(mesh.cells().size(), sumOp<label>());
 
         // These are actually warnings, not errors.
-        if (nTotCells && (nEmpty % nTotCells))
+        if (nCells && (nEmpty % nCells))
         {
             Info<< " ***Total number of faces on empty patches"
                 << " is not divisible by the number of cells in the mesh."
@@ -335,7 +335,7 @@ Foam::label Foam::checkTopology
         {
             noFailedChecks++;
 
-            label nPoints = returnReduce(points.size(), sumOp<label>());
+            const label nPoints = returnReduce(points.size(), sumOp<label>());
 
             Info<< "  <<Writing " << nPoints
                 << " unused points to set " << points.name() << endl;
@@ -472,7 +472,7 @@ Foam::label Foam::checkTopology
             }
         }
 
-        label nOneCells = returnReduce(oneCells.size(), sumOp<label>());
+        const label nOneCells = returnReduce(oneCells.size(), sumOp<label>());
 
         if (nOneCells > 0)
         {
@@ -488,7 +488,7 @@ Foam::label Foam::checkTopology
             }
         }
 
-        label nTwoCells = returnReduce(twoCells.size(), sumOp<label>());
+        const label nTwoCells = returnReduce(twoCells.size(), sumOp<label>());
 
         if (nTwoCells > 0)
         {
@@ -635,7 +635,7 @@ Foam::label Foam::checkTopology
                 cellRegions[i].write();
             }
 
-            label nPoints = returnReduce(points.size(), sumOp<label>());
+            const label nPoints = returnReduce(points.size(), sumOp<label>());
             if (nPoints)
             {
                 Info<< "  <<Writing " << nPoints
diff --git a/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C b/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
index ca13af55b9..5cdc1a16c3 100644
--- a/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
+++ b/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -138,7 +138,7 @@ void filterPatches(fvMesh& mesh, const wordHashSet& addedPatchNames)
             if
             (
                 isA<coupledPolyPatch>(pp)
-             || returnReduce(pp.size(), sumOp<label>())
+             || returnReduceOr(pp.size())
              || addedPatchNames.found(pp.name())
             )
             {
diff --git a/applications/utilities/mesh/manipulation/createPatch/createPatch.C b/applications/utilities/mesh/manipulation/createPatch/createPatch.C
index 0681cd9d77..bdd0489184 100644
--- a/applications/utilities/mesh/manipulation/createPatch/createPatch.C
+++ b/applications/utilities/mesh/manipulation/createPatch/createPatch.C
@@ -686,7 +686,7 @@ void syncPoints
 
     //- Note: hasTransformation is only used for warning messages so
     //  reduction not strictly necessary.
-    //reduce(hasTransformation, orOp<bool>());
+    //Pstream::reduceOr(hasTransformation);
 
     // Synchronize multiple shared points.
     const globalMeshData& pd = mesh.globalData();
diff --git a/applications/utilities/mesh/manipulation/orientFaceZone/orientFaceZone.C b/applications/utilities/mesh/manipulation/orientFaceZone/orientFaceZone.C
index d98c4f82e2..26b4f44a5d 100644
--- a/applications/utilities/mesh/manipulation/orientFaceZone/orientFaceZone.C
+++ b/applications/utilities/mesh/manipulation/orientFaceZone/orientFaceZone.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -272,7 +273,7 @@ int main(int argc, char *argv[])
         }
 
 
-        if (returnReduce(changedEdges.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(changedEdges.empty()))
         {
             break;
         }
diff --git a/applications/utilities/mesh/manipulation/renumberMesh/renumberMesh.C b/applications/utilities/mesh/manipulation/renumberMesh/renumberMesh.C
index 13cac5a3cd..e15c5f84fb 100644
--- a/applications/utilities/mesh/manipulation/renumberMesh/renumberMesh.C
+++ b/applications/utilities/mesh/manipulation/renumberMesh/renumberMesh.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -1103,9 +1103,7 @@ int main(int argc, char *argv[])
         // Update proc maps
         if (cellProcAddressing.headerOk())
         {
-            bool localOk = (cellProcAddressing.size() == mesh.nCells());
-
-            if (returnReduce(localOk, andOp<bool>()))
+            if (returnReduceAnd(cellProcAddressing.size() == mesh.nCells()))
             {
                 Info<< "Renumbering processor cell decomposition map "
                     << cellProcAddressing.name() << endl;
@@ -1129,9 +1127,7 @@ int main(int argc, char *argv[])
 
         if (faceProcAddressing.headerOk())
         {
-            bool localOk = (faceProcAddressing.size() == mesh.nFaces());
-
-            if (returnReduce(localOk, andOp<bool>()))
+            if (returnReduceAnd(faceProcAddressing.size() == mesh.nFaces()))
             {
                 Info<< "Renumbering processor face decomposition map "
                     << faceProcAddressing.name() << endl;
@@ -1171,9 +1167,7 @@ int main(int argc, char *argv[])
 
         if (pointProcAddressing.headerOk())
         {
-            bool localOk = (pointProcAddressing.size() == mesh.nPoints());
-
-            if (returnReduce(localOk, andOp<bool>()))
+            if (returnReduceAnd(pointProcAddressing.size() == mesh.nPoints()))
             {
                 Info<< "Renumbering processor point decomposition map "
                     << pointProcAddressing.name() << endl;
@@ -1197,12 +1191,13 @@ int main(int argc, char *argv[])
 
         if (boundaryProcAddressing.headerOk())
         {
-            bool localOk =
+            if
             (
-                boundaryProcAddressing.size()
-             == mesh.boundaryMesh().size()
-            );
-            if (returnReduce(localOk, andOp<bool>()))
+                returnReduceAnd
+                (
+                    boundaryProcAddressing.size() == mesh.boundaryMesh().size()
+                )
+            )
             {
                 // No renumbering needed
             }
diff --git a/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C b/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
index 4b5ceee7b7..1ad2ab9462 100644
--- a/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
+++ b/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
@@ -847,7 +847,7 @@ void createAndWriteRegion
 
         if (!isA<processorPolyPatch>(pp))
         {
-            if (returnReduce(pp.size(), sumOp<label>()) > 0)
+            if (returnReduceOr(pp.size()))
             {
                 oldToNew[patchi] = newI;
                 if (!addedPatches.found(patchi))
diff --git a/applications/utilities/parallelProcessing/reconstructParMesh/reconstructParMesh.C b/applications/utilities/parallelProcessing/reconstructParMesh/reconstructParMesh.C
index 7eedd53eaa..8a680c3dd9 100644
--- a/applications/utilities/parallelProcessing/reconstructParMesh/reconstructParMesh.C
+++ b/applications/utilities/parallelProcessing/reconstructParMesh/reconstructParMesh.C
@@ -252,7 +252,7 @@ autoPtr<mapPolyMesh> mergeSharedPoints
     Info<< "mergeSharedPoints : detected " << pointToMaster.size()
         << " points that are to be merged." << endl;
 
-    if (returnReduce(pointToMaster.size(), sumOp<label>()) == 0)
+    if (returnReduceAnd(pointToMaster.empty()))
     {
         return nullptr;
     }
diff --git a/applications/utilities/parallelProcessing/redistributePar/parLagrangianDistributorTemplates.C b/applications/utilities/parallelProcessing/redistributePar/parLagrangianDistributorTemplates.C
index 68e13363e1..401456f0d6 100644
--- a/applications/utilities/parallelProcessing/redistributePar/parLagrangianDistributorTemplates.C
+++ b/applications/utilities/parallelProcessing/redistributePar/parLagrangianDistributorTemplates.C
@@ -88,11 +88,8 @@ Foam::label Foam::parLagrangianDistributor::distributeFields
         if (!nFields)
         {
             // Performing an all-to-one (reconstruct)?
-            reconstruct = returnReduce
-            (
-                (!map.constructSize() || Pstream::master()),
-                andOp<bool>()
-            );
+            reconstruct =
+                returnReduceAnd(!map.constructSize() || Pstream::master());
         }
 
         if (verbose_)
@@ -195,11 +192,8 @@ Foam::label Foam::parLagrangianDistributor::distributeFieldFields
         if (!nFields)
         {
             // Performing an all-to-one (reconstruct)?
-            reconstruct = returnReduce
-            (
-                (!map.constructSize() || Pstream::master()),
-                andOp<bool>()
-            );
+            reconstruct =
+                returnReduceAnd(!map.constructSize() || Pstream::master());
         }
 
         if (verbose_)
@@ -344,11 +338,8 @@ Foam::label Foam::parLagrangianDistributor::distributeStoredFields
         if (!nFields)
         {
             // Performing an all-to-one (reconstruct)?
-            reconstruct = returnReduce
-            (
-                (!map.constructSize() || Pstream::master()),
-                andOp<bool>()
-            );
+            reconstruct =
+                returnReduceAnd(!map.constructSize() || Pstream::master());
         }
 
         if (verbose_)
diff --git a/applications/utilities/parallelProcessing/redistributePar/redistributePar.C b/applications/utilities/parallelProcessing/redistributePar/redistributePar.C
index b5fa4d1f19..6221317d78 100644
--- a/applications/utilities/parallelProcessing/redistributePar/redistributePar.C
+++ b/applications/utilities/parallelProcessing/redistributePar/redistributePar.C
@@ -1547,7 +1547,7 @@ int main(int argc, char *argv[])
                 if
                 (
                     !volMeshHaveUndecomposed
-                 || !returnReduce(haveVolAddressing, andOp<bool>())
+                 || !returnReduceAnd(haveVolAddressing)
                 )
                 {
                     Info<< "No undecomposed mesh. Creating from: "
@@ -1615,7 +1615,7 @@ int main(int argc, char *argv[])
                  &&
                     (
                         !areaMeshHaveUndecomposed
-                     || !returnReduce(haveAreaAddressing, andOp<bool>())
+                     || !returnReduceAnd(haveAreaAddressing)
                     )
                 )
                 {
diff --git a/applications/utilities/postProcessing/dataConversion/foamToEnsight/checkMeshMoving.H b/applications/utilities/postProcessing/dataConversion/foamToEnsight/checkMeshMoving.H
index c54e45cc3b..cbd5f35cd4 100644
--- a/applications/utilities/postProcessing/dataConversion/foamToEnsight/checkMeshMoving.H
+++ b/applications/utilities/postProcessing/dataConversion/foamToEnsight/checkMeshMoving.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -78,6 +78,6 @@ if (timeDirs.size() > 1)
 }
 
 // Ensure consistency
-reduce(hasMovingMesh, orOp<bool>());
+Pstream::reduceOr(hasMovingMesh);
 
 // ************************************************************************* //
diff --git a/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H b/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
index 2247b6a581..45ee1ee64a 100644
--- a/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
+++ b/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -38,7 +38,7 @@ if (doLagrangian)
         Info<< "Cloud " << cloudName << " (";
 
         const bool cloudExists =
-            returnReduce(currentCloudDirs.found(cloudName), orOp<bool>());
+            returnReduceOr(currentCloudDirs.found(cloudName));
 
         {
             autoPtr<ensightFile> os = ensCase.newCloud(cloudName);
@@ -82,7 +82,7 @@ if (doLagrangian)
                 const bool oldParRun = Pstream::parRun(false);
                 fieldExists = fieldObject.typeHeaderOk<IOField<scalar>>(false);
                 Pstream::parRun(oldParRun);  // Restore parallel state
-                reduce(fieldExists, orOp<bool>());
+                Pstream::reduceOr(fieldExists);
             }
 
             bool wrote = false;
diff --git a/applications/utilities/postProcessing/dataConversion/foamToEnsight/readFields.C b/applications/utilities/postProcessing/dataConversion/foamToEnsight/readFields.C
index 10cbaa2c95..6977d8bf58 100644
--- a/applications/utilities/postProcessing/dataConversion/foamToEnsight/readFields.C
+++ b/applications/utilities/postProcessing/dataConversion/foamToEnsight/readFields.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -64,9 +64,7 @@ Foam::label Foam::checkData
             }
         }
 
-        reduce(good, andOp<bool>());
-
-        if (good)
+        if (returnReduceAnd(good))
         {
             goodFields.insert(fieldName);
         }
diff --git a/applications/utilities/postProcessing/dataConversion/foamToVTK/convertLagrangian.H b/applications/utilities/postProcessing/dataConversion/foamToVTK/convertLagrangian.H
index f4af230525..de8c9c5d7c 100644
--- a/applications/utilities/postProcessing/dataConversion/foamToVTK/convertLagrangian.H
+++ b/applications/utilities/postProcessing/dataConversion/foamToVTK/convertLagrangian.H
@@ -64,7 +64,7 @@ if (doLagrangian)
             isCloud = true;
         }
 
-        if (!returnReduce(isCloud, orOp<bool>()))
+        if (!returnReduceOr(isCloud))
         {
             continue;
         }
@@ -76,7 +76,7 @@ if (doLagrangian)
         );
 
         // Are there cloud fields (globally)?
-        if (returnReduce(cloudObjs.empty(), andOp<bool>()))
+        if (returnReduceAnd(cloudObjs.empty()))
         {
             continue;
         }
diff --git a/applications/utilities/postProcessing/miscellaneous/postChannel/channelIndex.C b/applications/utilities/postProcessing/miscellaneous/postChannel/channelIndex.C
index cbb099fe13..0ab46241c7 100644
--- a/applications/utilities/postProcessing/miscellaneous/postChannel/channelIndex.C
+++ b/applications/utilities/postProcessing/miscellaneous/postChannel/channelIndex.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -68,7 +69,7 @@ void Foam::channelIndex::walkOppositeFaces
         blockedFace[facei] = true;
     }
 
-    while (returnReduce(frontFaces.size(), sumOp<label>()) > 0)
+    while (returnReduceOr(frontFaces.size()))
     {
         // Transfer across.
         boolList isFrontBndFace(nBnd, false);
diff --git a/applications/utilities/preProcessing/foamUpgradeCyclics/foamUpgradeCyclics.C b/applications/utilities/preProcessing/foamUpgradeCyclics/foamUpgradeCyclics.C
index db36f8f819..329bc82de4 100644
--- a/applications/utilities/preProcessing/foamUpgradeCyclics/foamUpgradeCyclics.C
+++ b/applications/utilities/preProcessing/foamUpgradeCyclics/foamUpgradeCyclics.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -238,7 +238,7 @@ void rewriteBoundary
 
     patches.reorder(oldToNew);
 
-    if (returnReduce(nOldCyclics, sumOp<label>()) > 0)
+    if (returnReduceOr(nOldCyclics))
     {
         if (dryrun)
         {
@@ -299,7 +299,7 @@ void rewriteField
 
     dictionary& boundaryField = fieldDict.subDict("boundaryField");
 
-    label nChanged = 0;
+    bool hasChange = false;
 
     forAllConstIters(thisNames, iter)
     {
@@ -337,13 +337,13 @@ void rewriteField
             );
             Info<< "    Adding entry " << nbrNames[patchName] << endl;
 
-            nChanged++;
+            hasChange = true;
         }
     }
 
     //Info<< "New boundaryField:" << boundaryField << endl;
 
-    if (returnReduce(nChanged, sumOp<label>()) > 0)
+    if (returnReduceOr(hasChange))
     {
         if (dryrun)
         {
diff --git a/applications/utilities/preProcessing/mapFieldsPar/mapLagrangian.C b/applications/utilities/preProcessing/mapFieldsPar/mapLagrangian.C
index 1de43414d8..dc9735628b 100644
--- a/applications/utilities/preProcessing/mapFieldsPar/mapLagrangian.C
+++ b/applications/utilities/preProcessing/mapFieldsPar/mapLagrangian.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2019 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -113,10 +113,9 @@ void mapLagrangian(const meshToMesh& interp)
 
         if
         (
-            returnReduce
+            returnReduceOr
             (
-                (objects.found("coordinates") || objects.found("positions")),
-                orOp<bool>()
+                objects.found("coordinates") || objects.found("positions")
             )
         )
         {
diff --git a/applications/utilities/preProcessing/viewFactorsGen/shootRays.H b/applications/utilities/preProcessing/viewFactorsGen/shootRays.H
index a5f808c392..c3d509e387 100644
--- a/applications/utilities/preProcessing/viewFactorsGen/shootRays.H
+++ b/applications/utilities/preProcessing/viewFactorsGen/shootRays.H
@@ -85,7 +85,7 @@ for (const int proci : Pstream::allProcs())
             }
         }
 
-    } while (returnReduce(i < myFc.size(), orOp<bool>()));
+    } while (returnReduceOr(i < myFc.size()));
 
     List<pointIndexHit> hitInfo(startIndex.size());
     surfacesMesh.findLine(start, end, hitInfo);
@@ -176,7 +176,7 @@ for (const int proci : Pstream::allProcs())
         firstLoop = false;
         iter ++;
 
-    } while (returnReduce(hitInfo.size(), orOp<bool>()) > 0 && iter < 10);
+    } while (returnReduceOr(hitInfo.size()) && iter < 10);
 
     startIndex.clear();
     end.clear();
diff --git a/applications/utilities/preProcessing/viewFactorsGen/viewFactorsGen.C b/applications/utilities/preProcessing/viewFactorsGen/viewFactorsGen.C
index 81d40e4871..9e8d6f6be4 100644
--- a/applications/utilities/preProcessing/viewFactorsGen/viewFactorsGen.C
+++ b/applications/utilities/preProcessing/viewFactorsGen/viewFactorsGen.C
@@ -531,15 +531,10 @@ int main(int argc, char *argv[])
         nFineFaces += patches[patchi].size();
     }
 
-    // total number of coarse faces
-    label totalNCoarseFaces = nCoarseFaces;
 
-    reduce(totalNCoarseFaces, sumOp<label>());
-
-    if (Pstream::master())
-    {
-        Info << "\nTotal number of coarse faces: "<< totalNCoarseFaces << endl;
-    }
+    Info<< "\nTotal number of coarse faces: "
+        << returnReduce(nCoarseFaces, sumOp<label>())
+        << endl;
 
     if (Pstream::master() && debug)
     {
@@ -829,15 +824,11 @@ int main(int argc, char *argv[])
         nCoarseFaces
     );
 
-    label totalPatches = coarsePatches.size();
-    reduce(totalPatches, maxOp<label>());
+    const label totalPatches =
+        returnReduce(coarsePatches.size(), maxOp<label>());
 
     // Matrix sum in j(Fij) for each i (if enclosure sum = 1)
-    scalarSquareMatrix sumViewFactorPatch
-    (
-        totalPatches,
-        0.0
-    );
+    scalarSquareMatrix sumViewFactorPatch(totalPatches, Zero);
 
     scalarList patchArea(totalPatches, Zero);
 
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
index db03e95838..cb8e6642c4 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/PstreamBuffers.C
@@ -482,7 +482,7 @@ bool Foam::PstreamBuffers::finishedSends
         }
     }
 
-    reduce(changed, orOp<bool>());
+    UPstream::reduceOr(changed);
 
     if (changed)
     {
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UOPstream.H b/src/OpenFOAM/db/IOstreams/Pstreams/UOPstream.H
index a316ee450c..80d5684b81 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UOPstream.H
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UOPstream.H
@@ -327,7 +327,7 @@ public:
         //  \return True on success
         static bool write
         (
-            const commsTypes commsType,
+            const UPstream::commsTypes commsType,
             const int toProcNo,
             const char* buf,
             const std::streamsize bufSize,
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
index 37ec9d5740..dfd7309c39 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C
@@ -434,7 +434,7 @@ Foam::UPstream::commsTypes Foam::UPstream::defaultCommsType
 
 namespace Foam
 {
-    // Register re-reader
+    //- Registered reader for UPstream::defaultCommsType
     class addcommsTypeToOpt
     :
         public ::Foam::simpleRegIOobject
diff --git a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
index 3a7438b67c..a36a77d97b 100644
--- a/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
+++ b/src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H
@@ -66,12 +66,12 @@ public:
     //- Types of communications
     enum class commsTypes : char
     {
-        blocking,       //!< "blocking"
-        scheduled,      //!< "scheduled"
-        nonBlocking     //!< "nonBlocking"
+        blocking,       //!< "blocking"    : (MPI_Bsend, MPI_Recv)
+        scheduled,      //!< "scheduled"   : (MPI_Send, MPI_Recv)
+        nonBlocking     //!< "nonBlocking" : (MPI_Isend, MPI_Irecv)
     };
 
-    //- Names of the communication types
+    //- Enumerated names for the communication types
     static const Enum<commsTypes> commsTypeNames;
 
 
diff --git a/src/OpenFOAM/db/dictionary/functionEntries/codeStream/codeStream.C b/src/OpenFOAM/db/dictionary/functionEntries/codeStream/codeStream.C
index 19ee8de2f6..22cf9c63ac 100644
--- a/src/OpenFOAM/db/dictionary/functionEntries/codeStream/codeStream.C
+++ b/src/OpenFOAM/db/dictionary/functionEntries/codeStream/codeStream.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -317,7 +317,7 @@ Foam::functionEntries::codeStream::getFunction
     bool haveLib = lib;
     if (!doingMasterOnlyReading(topDict))
     {
-        reduce(haveLib, andOp<bool>());
+        Pstream::reduceAnd(haveLib);
     }
 
     if (!haveLib)
diff --git a/src/OpenFOAM/db/dynamicLibrary/codedBase/codedBase.C b/src/OpenFOAM/db/dynamicLibrary/codedBase/codedBase.C
index 7870c770f1..fe5a286f01 100644
--- a/src/OpenFOAM/db/dynamicLibrary/codedBase/codedBase.C
+++ b/src/OpenFOAM/db/dynamicLibrary/codedBase/codedBase.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -332,7 +332,8 @@ void Foam::codedBase::createLibrary
             << " after waiting: have masterSize:" << masterSize
             << " and localSize:" << mySize << endl;
     }
-    reduce(create, orOp<bool>());
+
+    Pstream::reduceOr(create);  // MPI barrier
 }
 
 
diff --git a/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C b/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
index a94d5971c2..ce086e1cb8 100644
--- a/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
+++ b/src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C
@@ -1171,7 +1171,7 @@ bool Foam::functionObjectList::read()
                 FatalIOError.throwing(oldThrowingIOerr);
 
                 // Require valid functionObject on all processors
-                if (!returnReduce(bool(objPtr), andOp<bool>()))
+                if (!returnReduceAnd(bool(objPtr)))
                 {
                     objPtr.reset(nullptr);
                     ok = false;
diff --git a/src/OpenFOAM/expressions/exprDriver/exprDriverTemplates.C b/src/OpenFOAM/expressions/exprDriver/exprDriverTemplates.C
index 061a68f415..1d9c9f8403 100644
--- a/src/OpenFOAM/expressions/exprDriver/exprDriverTemplates.C
+++ b/src/OpenFOAM/expressions/exprDriver/exprDriverTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2010-2018 Bernhard Gschaider
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -309,8 +309,7 @@ bool Foam::expressions::exprDriver::isLocalVariable
         // Do size checking if requested
         if (good && expectedSize >= 0)
         {
-            good = (var.size() == expectedSize);
-            reduce(good, andOp<bool>());
+            good = returnReduceAnd(var.size() == expectedSize);
 
             if (debug && !good)
             {
diff --git a/src/OpenFOAM/expressions/fields/fieldExprDriverTemplates.C b/src/OpenFOAM/expressions/fields/fieldExprDriverTemplates.C
index 6cb9b3454f..abae85a638 100644
--- a/src/OpenFOAM/expressions/fields/fieldExprDriverTemplates.C
+++ b/src/OpenFOAM/expressions/fields/fieldExprDriverTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -52,7 +52,7 @@ Foam::expressions::fieldExpr::parseDriver::getField
 
         const label len = (hasPointData ? this->pointSize() : this->size());
 
-        if (returnReduce((vals.size() == len), andOp<bool>()))
+        if (returnReduceAnd(vals.size() == len))
         {
             // Return a copy of the field
             return tmp<Field<Type>>::New(vals);
diff --git a/src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.C b/src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.C
index 1ac929c4f4..718f1af38d 100644
--- a/src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.C
+++ b/src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.C
@@ -1077,18 +1077,16 @@ bool Foam::GeometricField<Type, PatchField, GeoMesh>::needReference() const
 
     bool needRef = true;
 
-    forAll(boundaryField_, patchi)
+    for (const auto& pf : boundaryField_)
     {
-        if (boundaryField_[patchi].fixesValue())
+        if (pf.fixesValue())
         {
             needRef = false;
             break;
         }
     }
 
-    reduce(needRef, andOp<bool>());
-
-    return needRef;
+    return returnReduceAnd(needRef);
 }
 
 
diff --git a/src/OpenFOAM/global/fileOperations/masterUncollatedFileOperation/masterUncollatedFileOperation.C b/src/OpenFOAM/global/fileOperations/masterUncollatedFileOperation/masterUncollatedFileOperation.C
index 89840c3600..d6c071cd84 100644
--- a/src/OpenFOAM/global/fileOperations/masterUncollatedFileOperation/masterUncollatedFileOperation.C
+++ b/src/OpenFOAM/global/fileOperations/masterUncollatedFileOperation/masterUncollatedFileOperation.C
@@ -2032,7 +2032,7 @@ Foam::fileOperations::masterUncollatedFileOperation::readStream
             }
             // Reduce (not broadcast)
             // - if we have multiple master files (FUTURE)
-            reduce(bigSize, orOp<bool>());  //, UPstream::msgType(), comm_);
+            Pstream::reduceOr(bigSize);  //, comm_);
 
             const UPstream::commsTypes myCommsType
             (
diff --git a/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/GAMGProcAgglomerations/procFacesGAMGProcAgglomeration/procFacesGAMGProcAgglomeration.C b/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/GAMGProcAgglomerations/procFacesGAMGProcAgglomeration/procFacesGAMGProcAgglomeration.C
index 2256aa117b..9202dd0241 100644
--- a/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/GAMGProcAgglomerations/procFacesGAMGProcAgglomeration/procFacesGAMGProcAgglomeration.C
+++ b/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/GAMGProcAgglomerations/procFacesGAMGProcAgglomeration/procFacesGAMGProcAgglomeration.C
@@ -208,9 +208,9 @@ bool Foam::procFacesGAMGProcAgglomeration::doProcessorAgglomeration
     const lduMesh& mesh
 ) const
 {
-    // Check the need for further agglomeration on all processors
+    // Check the need for further agglomeration on any processors
     bool doAgg = mesh.lduAddr().size() < nAgglomeratingCells_;
-    mesh.reduce(doAgg, orOp<bool>());
+    UPstream::reduceOr(doAgg, mesh.comm());
     return doAgg;
 }
 
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalPoints.C b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalPoints.C
index dcfbb22f56..e500f48636 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalPoints.C
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalPoints.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -276,7 +276,7 @@ bool Foam::globalPoints::mergeInfo
     // Updates database of current information on meshpoints with nbrInfo.  Uses
     // mergeInfo above. Returns true if data kept for meshPointi changed.
 
-    label infoChanged = false;
+    bool infoChanged = false;
 
     // Get the index into the procPoints list.
     const auto iter = meshToProcPoint_.cfind(localPointi);
@@ -325,7 +325,7 @@ bool Foam::globalPoints::storeInitialInfo
     // Updates database of current information on meshpoints with nbrInfo.  Uses
     // mergeInfo above. Returns true if data kept for meshPointi changed.
 
-    label infoChanged = false;
+    bool infoChanged = false;
 
     // Get the index into the procPoints list.
     const auto iter = meshToProcPoint_.find(localPointi);
@@ -929,8 +929,7 @@ void Foam::globalPoints::calculateSharedPoints
         neighbourList = meshToProcPoint_;
     }
 
-    // Exchange until nothing changes on all processors.
-    bool changed = false;
+    // Exchange until nothing changes on any processors.
 
     do
     {
@@ -959,10 +958,7 @@ void Foam::globalPoints::calculateSharedPoints
             changedPoints
         );
 
-        changed = changedPoints.size() > 0;
-        reduce(changed, orOp<bool>());
-
-    } while (changed);
+    } while (returnReduceOr(changedPoints.size()));
 
 
     //Pout<< "**ALL** connected points:" << endl;
diff --git a/src/OpenFOAM/meshes/polyMesh/polyBoundaryMesh/polyBoundaryMesh.C b/src/OpenFOAM/meshes/polyMesh/polyBoundaryMesh/polyBoundaryMesh.C
index ba934b81c6..862e776042 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyBoundaryMesh/polyBoundaryMesh.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyBoundaryMesh/polyBoundaryMesh.C
@@ -1046,9 +1046,7 @@ bool Foam::polyBoundaryMesh::checkParallelSync(const bool report) const
     }
 
     // Reduce (not broadcast) to respect local out-of-order errors (first loop)
-    reduce(hasError, orOp<bool>());
-
-    return hasError;
+    return returnReduceOr(hasError);
 }
 
 
@@ -1091,7 +1089,7 @@ bool Foam::polyBoundaryMesh::checkDefinition(const bool report) const
         nextPatchStart += bm[patchi].size();
     }
 
-    reduce(hasError, orOp<bool>());
+    Pstream::reduceOr(hasError);
 
     if (debug || report)
     {
diff --git a/src/OpenFOAM/meshes/polyMesh/polyMesh.C b/src/OpenFOAM/meshes/polyMesh/polyMesh.C
index 8b3471af4d..ddf6111a33 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyMesh.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyMesh.C
@@ -62,8 +62,8 @@ void Foam::polyMesh::calcDirections() const
     // Knock out empty and wedge directions. Note:they will be present on all
     // domains.
 
-    label nEmptyPatches = 0;
-    label nWedgePatches = 0;
+    bool hasEmptyPatches = false;
+    bool hasWedgePatches = false;
 
     vector emptyDirVec = Zero;
     vector wedgeDirVec = Zero;
@@ -79,7 +79,7 @@ void Foam::polyMesh::calcDirections() const
 
             if (pp.size())
             {
-                nEmptyPatches++;
+                hasEmptyPatches = true;
                 emptyDirVec += sum(cmptMag(fa));
             }
         }
@@ -93,16 +93,14 @@ void Foam::polyMesh::calcDirections() const
 
             if (pp.size())
             {
-                nWedgePatches++;
+                hasWedgePatches = true;
                 wedgeDirVec += cmptMag(wpp.centreNormal());
             }
         }
     }
 
-    reduce(nEmptyPatches, maxOp<label>());
-    reduce(nWedgePatches, maxOp<label>());
 
-    if (nEmptyPatches)
+    if (returnReduceOr(hasEmptyPatches))
     {
         reduce(emptyDirVec, sumOp<vector>());
 
@@ -126,7 +124,7 @@ void Foam::polyMesh::calcDirections() const
 
     geometricD_ = solutionD_;
 
-    if (nWedgePatches)
+    if (returnReduceOr(hasWedgePatches))
     {
         reduce(wedgeDirVec, sumOp<vector>());
 
@@ -339,21 +337,21 @@ Foam::polyMesh::polyMesh(const IOobject& io, const bool doInit)
         neighbour_.write();
     }
 
-    // Warn if global empty mesh
-    if (returnReduce(boundary_.empty(), orOp<bool>()))
+    if (returnReduceOr(boundary_.empty()))
     {
         WarningInFunction
-            << "mesh missing boundary on one or more domains" << endl;
+            << "Missing mesh boundary on one or more domains" << endl;
 
-        if (returnReduce(nPoints(), sumOp<label>()) == 0)
+        // Warn if global empty mesh
+        if (returnReduceAnd(!nPoints()))
         {
             WarningInFunction
-                << "no points in mesh" << endl;
+                << "No points in mesh" << endl;
         }
-        if (returnReduce(nCells(), sumOp<label>()) == 0)
+        if (returnReduceAnd(!nCells()))
         {
             WarningInFunction
-                << "no cells in mesh" << endl;
+                << "No cells in mesh" << endl;
         }
     }
 
@@ -802,14 +800,10 @@ void Foam::polyMesh::resetPrimitives
         boundary_.calcGeometry();
 
         // Warn if global empty mesh
-        if
-        (
-            (returnReduce(nPoints(), sumOp<label>()) == 0)
-         || (returnReduce(nCells(), sumOp<label>()) == 0)
-        )
+        if (returnReduceAnd(!nPoints()) || returnReduceAnd(!nCells()))
         {
             FatalErrorInFunction
-                << "no points or no cells in mesh" << endl;
+                << "No points or no cells in mesh" << endl;
         }
     }
 }
diff --git a/src/OpenFOAM/meshes/polyMesh/polyMeshFromShapeMesh.C b/src/OpenFOAM/meshes/polyMesh/polyMeshFromShapeMesh.C
index c7dbe3e2b8..d72f0486d4 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyMeshFromShapeMesh.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyMeshFromShapeMesh.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016, 2020 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -634,7 +634,6 @@ Foam::polyMesh::polyMesh
 
     label nAllPatches = boundaryFaces.size();
 
-
     label nDefaultFaces = nFaces - defaultPatchStart;
     if (syncPar)
     {
diff --git a/src/OpenFOAM/meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C b/src/OpenFOAM/meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C
index 3a67f06950..717fde2a0e 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C
@@ -776,7 +776,7 @@ Foam::labelList Foam::polyMeshTetDecomposition::adjustTetBasePtIs
 
     syncTools::syncFaceList(mesh, tetBasePtIs, maxEqOp<label>());
 
-    if (report && returnReduce(nAdapted, sumOp<label>()))
+    if (report && returnReduceOr(nAdapted))
     {
         Pout<< "Adapted starting point of triangulation on "
             << nAdapted << " faces." << endl;
diff --git a/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/symmetryPlane/symmetryPlanePolyPatch.C b/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/symmetryPlane/symmetryPlanePolyPatch.C
index 9761b19140..b71af44be2 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/symmetryPlane/symmetryPlanePolyPatch.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/symmetryPlane/symmetryPlanePolyPatch.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2015 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -46,9 +47,9 @@ void Foam::symmetryPlanePolyPatch::calcGeometry(PstreamBuffers&)
 {
     if (n_ == vector::rootMax)
     {
-        if (returnReduce(size(), sumOp<label>()))
+        if (returnReduceOr(size()))
         {
-            const vectorField& nf(faceNormals());
+            const vectorField& nf = faceNormals();
             n_ = gAverage(nf);
 
             if (debug)
diff --git a/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/wedge/wedgePolyPatch.C b/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/wedge/wedgePolyPatch.C
index b32042ff47..d2c6239549 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/wedge/wedgePolyPatch.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/constraint/wedge/wedgePolyPatch.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -50,9 +51,9 @@ void Foam::wedgePolyPatch::calcGeometry(PstreamBuffers&)
         return;
     }
 
-    if (returnReduce(size(), sumOp<label>()))
+    if (returnReduceOr(size()))
     {
-        const vectorField& nf(faceNormals());
+        const vectorField& nf = faceNormals();
         n_ = gAverage(nf);
 
         if (debug)
diff --git a/src/OpenFOAM/meshes/polyMesh/zones/faceZone/faceZone.C b/src/OpenFOAM/meshes/polyMesh/zones/faceZone/faceZone.C
index a85ebc8400..c4dc893424 100644
--- a/src/OpenFOAM/meshes/polyMesh/zones/faceZone/faceZone.C
+++ b/src/OpenFOAM/meshes/polyMesh/zones/faceZone/faceZone.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -601,7 +601,7 @@ bool Foam::faceZone::checkParallelSync(const bool report) const
         }
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
diff --git a/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheck.C b/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheck.C
index cce5ed1a5c..c45ad6ca4b 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheck.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheck.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -425,8 +425,7 @@ bool Foam::primitiveMesh::checkFaceOrthogonality
 
     if (debug || report)
     {
-        label neiSize = ortho.size();
-        reduce(neiSize, sumOp<label>());
+        const label neiSize = returnReduce(ortho.size(), sumOp<label>());
 
         if (neiSize > 0)
         {
@@ -929,9 +928,9 @@ bool Foam::primitiveMesh::checkUpperTriangular
     label internal = nInternalFaces();
 
     // Has error occurred?
-    bool error = false;
-    // Have multiple faces been detected?
-    label nMultipleCells = false;
+    bool hasError = false;
+    // Multiple faces detected?
+    label nMultipleCells = 0;
 
     // Loop through faceCells once more and make sure that for internal cell
     // the first label is smaller
@@ -939,7 +938,7 @@ bool Foam::primitiveMesh::checkUpperTriangular
     {
         if (own[facei] >= nei[facei])
         {
-            error  = true;
+            hasError = true;
 
             if (setPtr)
             {
@@ -1024,7 +1023,7 @@ bool Foam::primitiveMesh::checkUpperTriangular
             }
             else if (thisFace < prevFace)
             {
-                error = true;
+                hasError = true;
 
                 if (setPtr)
                 {
@@ -1042,7 +1041,7 @@ bool Foam::primitiveMesh::checkUpperTriangular
         }
     }
 
-    reduce(error, orOp<bool>());
+    Pstream::reduceOr(hasError);
     reduce(nMultipleCells, sumOp<label>());
 
     if ((debug || report) && nMultipleCells > 0)
@@ -1051,7 +1050,7 @@ bool Foam::primitiveMesh::checkUpperTriangular
             << " neighbouring cells with multiple inbetween faces." << endl;
     }
 
-    if (error)
+    if (hasError)
     {
         if (debug || report)
         {
diff --git a/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheckEdgeLength.C b/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheckEdgeLength.C
index 9918afa87a..01bdb8441f 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheckEdgeLength.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/primitiveMeshCheck/primitiveMeshCheckEdgeLength.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -69,8 +69,7 @@ bool Foam::primitiveMesh::checkEdgeLength
     reduce(minLenSqr, minOp<scalar>());
     reduce(maxLenSqr, maxOp<scalar>());
 
-    label nSmall = smallEdgeSet.size();
-    reduce(nSmall, sumOp<label>());
+    label nSmall = returnReduce(smallEdgeSet.size(), sumOp<label>());
 
     if (setPtr)
     {
diff --git a/src/Pstream/dummy/UOPstreamWrite.C b/src/Pstream/dummy/UOPstreamWrite.C
index 9acde63b74..7589556b5d 100644
--- a/src/Pstream/dummy/UOPstreamWrite.C
+++ b/src/Pstream/dummy/UOPstreamWrite.C
@@ -41,7 +41,7 @@ bool Foam::UOPstream::bufferIPCsend()
 
 bool Foam::UOPstream::write
 (
-    const commsTypes commsType,
+    const UPstream::commsTypes commsType,
     const int toProcNo,
     const char* buf,
     const std::streamsize bufSize,
diff --git a/src/Pstream/mpi/UOPstreamWrite.C b/src/Pstream/mpi/UOPstreamWrite.C
index 9b61558b7e..4ee1dc87ad 100644
--- a/src/Pstream/mpi/UOPstreamWrite.C
+++ b/src/Pstream/mpi/UOPstreamWrite.C
@@ -52,7 +52,7 @@ bool Foam::UOPstream::bufferIPCsend()
 
 bool Foam::UOPstream::write
 (
-    const commsTypes commsType,
+    const UPstream::commsTypes commsType,
     const int toProcNo,
     const char* buf,
     const std::streamsize bufSize,
@@ -65,7 +65,7 @@ bool Foam::UOPstream::write
         Pout<< "UOPstream::write : starting write to:" << toProcNo
             << " tag:" << tag
             << " comm:" << communicator << " size:" << label(bufSize)
-            << " commsType:" << UPstream::commsTypeNames[commsType]
+            << " commType:" << UPstream::commsTypeNames[commsType]
             << Foam::endl;
     }
     if (UPstream::warnComm != -1 && communicator != UPstream::warnComm)
@@ -73,7 +73,7 @@ bool Foam::UOPstream::write
         Pout<< "UOPstream::write : starting write to:" << toProcNo
             << " tag:" << tag
             << " comm:" << communicator << " size:" << label(bufSize)
-            << " commsType:" << UPstream::commsTypeNames[commsType]
+            << " commType:" << UPstream::commsTypeNames[commsType]
             << " warnComm:" << UPstream::warnComm
             << Foam::endl;
         error::printStack(Pout);
@@ -154,7 +154,7 @@ bool Foam::UOPstream::write
         {
             Pout<< "UOPstream::write : started write to:" << toProcNo
                 << " tag:" << tag << " size:" << label(bufSize)
-                << " commsType:" << UPstream::commsTypeNames[commsType]
+                << " commType:" << UPstream::commsTypeNames[commsType]
                 << " request:" << PstreamGlobals::outstandingRequests_.size()
                 << Foam::endl;
         }
diff --git a/src/dynamicFvMesh/dynamicMotionSolverFvMeshAMI/dynamicMotionSolverFvMeshAMI.C b/src/dynamicFvMesh/dynamicMotionSolverFvMeshAMI/dynamicMotionSolverFvMeshAMI.C
index d041c4b302..bb94134e1f 100644
--- a/src/dynamicFvMesh/dynamicMotionSolverFvMeshAMI/dynamicMotionSolverFvMeshAMI.C
+++ b/src/dynamicFvMesh/dynamicMotionSolverFvMeshAMI/dynamicMotionSolverFvMeshAMI.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -155,9 +155,7 @@ bool Foam::dynamicMotionSolverFvMeshAMI::update()
         changeRequired = pp.changeTopology() || changeRequired;
     }
 
-    reduce(changeRequired, orOp<bool>());
-
-    if (changeRequired)
+    if (returnReduceOr(changeRequired))
     {
         polyTopoChange polyTopo(*this);
 
diff --git a/src/dynamicFvMesh/dynamicRefineFvMesh/dynamicRefineFvMesh.C b/src/dynamicFvMesh/dynamicRefineFvMesh/dynamicRefineFvMesh.C
index fcfc39d271..d0f0d3ad7f 100644
--- a/src/dynamicFvMesh/dynamicRefineFvMesh/dynamicRefineFvMesh.C
+++ b/src/dynamicFvMesh/dynamicRefineFvMesh/dynamicRefineFvMesh.C
@@ -155,7 +155,7 @@ void Foam::dynamicRefineFvMesh::calculateProtectedCells
             }
         }
 
-        if (!returnReduce(hasExtended, orOp<bool>()))
+        if (!returnReduceOr(hasExtended))
         {
             break;
         }
@@ -1250,7 +1250,7 @@ bool Foam::dynamicRefineFvMesh::init(const bool doInit)
         checkEightAnchorPoints(protectedCell_);
     }
 
-    if (!returnReduce(protectedCell_.any(), orOp<bool>()))
+    if (!returnReduceOr(protectedCell_.any()))
     {
         protectedCell_.clear();
     }
@@ -1388,12 +1388,7 @@ bool Foam::dynamicRefineFvMesh::updateTopology()
                 )
             );
 
-            const label nCellsToRefine = returnReduce
-            (
-                cellsToRefine.size(), sumOp<label>()
-            );
-
-            if (nCellsToRefine > 0)
+            if (returnReduceOr(cellsToRefine.size()))
             {
                 // Refine/update mesh and map fields
                 autoPtr<mapPolyMesh> map = refine(cellsToRefine);
@@ -1447,13 +1442,7 @@ bool Foam::dynamicRefineFvMesh::updateTopology()
                 )
             );
 
-            const label nSplitPoints = returnReduce
-            (
-                pointsToUnrefine.size(),
-                sumOp<label>()
-            );
-
-            if (nSplitPoints > 0)
+            if (returnReduceOr(pointsToUnrefine.size()))
             {
                 // Refine/update mesh
                 unrefine(pointsToUnrefine);
diff --git a/src/dynamicMesh/createShellMesh/createShellMesh.C b/src/dynamicMesh/createShellMesh/createShellMesh.C
index 364b5e7667..c70db89dfc 100644
--- a/src/dynamicMesh/createShellMesh/createShellMesh.C
+++ b/src/dynamicMesh/createShellMesh/createShellMesh.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -311,8 +311,7 @@ void Foam::createShellMesh::calcPointRegions
         }
 
 
-        label nChangedFaces = returnReduce(changedFaces.size(), sumOp<label>());
-        if (nChangedFaces == 0)
+        if (returnReduceAnd(changedFaces.empty()))
         {
             break;
         }
@@ -374,8 +373,7 @@ void Foam::createShellMesh::calcPointRegions
         );
 
 
-        label nChangedEdges = returnReduce(changedEdges.size(), sumOp<label>());
-        if (nChangedEdges == 0)
+        if (returnReduceAnd(changedEdges.empty()))
         {
             break;
         }
diff --git a/src/dynamicMesh/layerAdditionRemoval/layerAdditionRemoval.C b/src/dynamicMesh/layerAdditionRemoval/layerAdditionRemoval.C
index 74d5d6cd64..b8f21b03af 100644
--- a/src/dynamicMesh/layerAdditionRemoval/layerAdditionRemoval.C
+++ b/src/dynamicMesh/layerAdditionRemoval/layerAdditionRemoval.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -75,11 +75,13 @@ void Foam::layerAdditionRemoval::checkDefinition()
             << abort(FatalError);
     }
 
-    label nFaces = topoChanger().mesh().faceZones()[faceZoneID_.index()].size();
-
-    reduce(nFaces, sumOp<label>());
-
-    if (nFaces == 0)
+    if
+    (
+        returnReduceAnd
+        (
+            topoChanger().mesh().faceZones()[faceZoneID_.index()].empty()
+        )
+    )
     {
         FatalErrorInFunction
             << "Face extrusion zone contains no faces. "
diff --git a/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C b/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
index d3c6c2931f..d39775a7df 100644
--- a/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
+++ b/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2019 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -77,14 +77,7 @@ bool Foam::layerAdditionRemoval::validCollapse() const
             << nBoundaryHits << endl;
     }
 
-    if (returnReduce(nBoundaryHits, sumOp<label>()) > 0)
-    {
-        return false;
-    }
-    else
-    {
-        return true;
-    }
+    return !returnReduceOr(nBoundaryHits);
 }
 
 
diff --git a/src/dynamicMesh/layerAdditionRemoval/setLayerPairing.C b/src/dynamicMesh/layerAdditionRemoval/setLayerPairing.C
index f65234f996..a7d06e6479 100644
--- a/src/dynamicMesh/layerAdditionRemoval/setLayerPairing.C
+++ b/src/dynamicMesh/layerAdditionRemoval/setLayerPairing.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -169,10 +169,7 @@ bool Foam::layerAdditionRemoval::setLayerPairing() const
         }
     }
 
-    reduce(nPointErrors, sumOp<label>());
-    reduce(nFaceErrors, sumOp<label>());
-
-    if (nPointErrors > 0 || nFaceErrors > 0)
+    if (returnReduceOr(nPointErrors || nFaceErrors))
     {
         clearAddressing();
 
diff --git a/src/dynamicMesh/meshCut/meshModifiers/meshCutter/meshCutter.C b/src/dynamicMesh/meshCut/meshModifiers/meshCutter/meshCutter.C
index 7595c7ac07..a8da54e3eb 100644
--- a/src/dynamicMesh/meshCut/meshModifiers/meshCutter/meshCutter.C
+++ b/src/dynamicMesh/meshCut/meshModifiers/meshCutter/meshCutter.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -534,7 +534,7 @@ void Foam::meshCutter::setRefinement
     addedPoints_.clear();
     addedPoints_.resize(cuts.nLoops());
 
-    if (returnReduce(cuts.nLoops(), sumOp<label>()) == 0)
+    if (!returnReduceOr(cuts.nLoops()))
     {
         return;
     }
diff --git a/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C b/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
index c7efb0cff6..bfbd8f4f9e 100644
--- a/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
+++ b/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -504,11 +504,7 @@ Foam::multiDirRefinement::multiDirRefinement
         refineHex8(mesh, hexCells, writeMesh);
     }
 
-    label nRemainingCells = cellLabels_.size();
-
-    reduce(nRemainingCells, sumOp<label>());
-
-    if (nRemainingCells > 0)
+    if (returnReduceOr(cellLabels_.size()))
     {
         // Any cells to refine using meshCutter
 
@@ -547,11 +543,7 @@ Foam::multiDirRefinement::multiDirRefinement
         refineHex8(mesh, hexCells, writeMesh);
     }
 
-    label nRemainingCells = cellLabels_.size();
-
-    reduce(nRemainingCells, sumOp<label>());
-
-    if (nRemainingCells > 0)
+    if (returnReduceOr(cellLabels_.size()))
     {
         // Any cells to refine using meshCutter
 
diff --git a/src/dynamicMesh/meshCut/meshModifiers/refinementIterator/refinementIterator.C b/src/dynamicMesh/meshCut/meshModifiers/refinementIterator/refinementIterator.C
index 8c0255803b..2bc71b7ca3 100644
--- a/src/dynamicMesh/meshCut/meshModifiers/refinementIterator/refinementIterator.C
+++ b/src/dynamicMesh/meshCut/meshModifiers/refinementIterator/refinementIterator.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -108,10 +108,7 @@ Foam::Map<Foam::label> Foam::refinementIterator::setRefinement
         // Determine cut pattern.
         cellCuts cuts(mesh_, cellWalker_, currentRefCells);
 
-        label nCuts = cuts.nLoops();
-        reduce(nCuts, sumOp<label>());
-
-        if (nCuts == 0)
+        if (!returnReduceOr(cuts.nLoops()))
         {
             if (debug)
             {
@@ -266,13 +263,12 @@ Foam::Map<Foam::label> Foam::refinementIterator::setRefinement
         }
 
         // Stop only if all finished or all can't refine any further.
-        stop = (nRefCells == 0) || (nRefCells == oldRefCells);
-        reduce(stop, andOp<bool>());
+        stop = returnReduceAnd(nRefCells == 0 || nRefCells == oldRefCells);
     }
     while (!stop);
 
 
-    if (returnReduce((nRefCells == oldRefCells), andOp<bool>()))
+    if (returnReduceAnd(nRefCells == oldRefCells))
     {
         WarningInFunction
             << "stopped refining."
diff --git a/src/dynamicMesh/motionSolvers/displacement/displacement/zoneMotion.C b/src/dynamicMesh/motionSolvers/displacement/displacement/zoneMotion.C
index d02bc63415..4b2c9fc4c0 100644
--- a/src/dynamicMesh/motionSolvers/displacement/displacement/zoneMotion.C
+++ b/src/dynamicMesh/motionSolvers/displacement/displacement/zoneMotion.C
@@ -131,7 +131,7 @@ Foam::zoneMotion::zoneMotion
 
     // No cell points selected (as set or zones) => move all points
 
-    moveAllCells_ = returnReduce(pointIDs_.empty(), andOp<bool>());
+    moveAllCells_ = returnReduceAnd(pointIDs_.empty());
 
     if (moveAllCells_)
     {
diff --git a/src/dynamicMesh/polyMeshFilter/polyMeshFilter.C b/src/dynamicMesh/polyMeshFilter/polyMeshFilter.C
index 3f2e76dc4f..b0e057b3a5 100644
--- a/src/dynamicMesh/polyMeshFilter/polyMeshFilter.C
+++ b/src/dynamicMesh/polyMeshFilter/polyMeshFilter.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -283,7 +284,7 @@ Foam::label Foam::polyMeshFilter::filterFacesLoop(const label nOriginalBadFaces)
                 }
             }
 
-            reduce(newBadFaces, orOp<bool>());
+            Pstream::reduceOr(newBadFaces);
         }
         else
         {
diff --git a/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C b/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
index fa1d8b90dc..9db2a1d408 100644
--- a/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
+++ b/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
@@ -2006,7 +2006,7 @@ void Foam::addPatchCellLayer::setRefinement
                 Pout<< "nChanged:" << nChanged << endl;
             }
 
-            if (returnReduce(nChanged, sumOp<label>()) == 0)
+            if (!returnReduceOr(nChanged))
             {
                 break;
             }
diff --git a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8.C b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8.C
index 512fbcb8b5..69a5bce97d 100644
--- a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8.C
+++ b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8.C
@@ -4991,7 +4991,7 @@ void Foam::hexRef8::checkRefinementLevels
     //        }
     //    }
     //
-    //    if (returnReduce(nHanging, sumOp<label>()) > 0)
+    //    if (returnReduceOr(nHanging))
     //    {
     //        FatalErrorInFunction
     //            << "Detected a point used by two edges only (hanging point)"
diff --git a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8Data.C b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8Data.C
index 388dcbeda0..ddd823ab10 100644
--- a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8Data.C
+++ b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/hexRef8Data.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2017 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -45,7 +45,7 @@ Foam::hexRef8Data::hexRef8Data(const IOobject& io)
         IOobject rio(io, "cellLevel");
 
         // haveFile
-        if (returnReduce(rio.typeHeaderOk<Type>(true), orOp<bool>()))
+        if (returnReduceOr(rio.typeHeaderOk<Type>(true)))
         {
             Info<< "Reading hexRef8 data : " << rio.name() << endl;
             cellLevelPtr_.reset(new Type(rio));
@@ -56,7 +56,7 @@ Foam::hexRef8Data::hexRef8Data(const IOobject& io)
         IOobject rio(io, "pointLevel");
 
         // haveFile
-        if (returnReduce(rio.typeHeaderOk<Type>(true), orOp<bool>()))
+        if (returnReduceOr(rio.typeHeaderOk<Type>(true)))
         {
             Info<< "Reading hexRef8 data : " << rio.name() << endl;
             pointLevelPtr_.reset(new Type(rio));
@@ -67,7 +67,7 @@ Foam::hexRef8Data::hexRef8Data(const IOobject& io)
         IOobject rio(io, "level0Edge");
 
         // haveFile
-        if (returnReduce(rio.typeHeaderOk<Type>(true), orOp<bool>()))
+        if (returnReduceOr(rio.typeHeaderOk<Type>(true)))
         {
             Info<< "Reading hexRef8 data : " << rio.name() << endl;
             level0EdgePtr_.reset(new Type(rio));
@@ -78,7 +78,7 @@ Foam::hexRef8Data::hexRef8Data(const IOobject& io)
         IOobject rio(io, "refinementHistory");
 
         // haveFile
-        if (returnReduce(rio.typeHeaderOk<Type>(true), orOp<bool>()))
+        if (returnReduceOr(rio.typeHeaderOk<Type>(true)))
         {
             Info<< "Reading hexRef8 data : " << rio.name() << endl;
             refHistoryPtr_.reset(new Type(rio));
@@ -237,7 +237,7 @@ void Foam::hexRef8Data::sync(const IOobject& io)
 {
     const polyMesh& mesh = dynamic_cast<const polyMesh&>(io.db());
 
-    bool hasCellLevel = returnReduce(bool(cellLevelPtr_), orOp<bool>());
+    bool hasCellLevel = returnReduceOr(bool(cellLevelPtr_));
     if (hasCellLevel && !cellLevelPtr_)
     {
         IOobject rio(io, "cellLevel");
@@ -248,7 +248,7 @@ void Foam::hexRef8Data::sync(const IOobject& io)
         );
     }
 
-    bool hasPointLevel = returnReduce(bool(pointLevelPtr_), orOp<bool>());
+    bool hasPointLevel = returnReduceOr(bool(pointLevelPtr_));
     if (hasPointLevel && !pointLevelPtr_)
     {
         IOobject rio(io, "pointLevel");
@@ -259,7 +259,7 @@ void Foam::hexRef8Data::sync(const IOobject& io)
         );
     }
 
-    bool hasLevel0Edge = returnReduce(bool(level0EdgePtr_), orOp<bool>());
+    bool hasLevel0Edge = returnReduceOr(bool(level0EdgePtr_));
     if (hasLevel0Edge)
     {
         // Get master length
@@ -280,7 +280,7 @@ void Foam::hexRef8Data::sync(const IOobject& io)
         }
     }
 
-    bool hasHistory = returnReduce(bool(refHistoryPtr_), orOp<bool>());
+    bool hasHistory = returnReduceOr(bool(refHistoryPtr_));
     if (hasHistory && !refHistoryPtr_)
     {
         IOobject rio(io, "refinementHistory");
diff --git a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/refinementHistory.C b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/refinementHistory.C
index 981ed540ba..e2b1e23818 100644
--- a/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/refinementHistory.C
+++ b/src/dynamicMesh/polyTopoChange/polyTopoChange/hexRef8/refinementHistory.C
@@ -490,8 +490,8 @@ void Foam::refinementHistory::add
 
     if (refinementHistory::debug)
     {
-        reduce(nUnblocked, sumOp<label>());
-        Info<< type() << " : unblocked " << nUnblocked << " faces" << endl;
+        Info<< type() << " : unblocked "
+            << returnReduce(nUnblocked, sumOp<label>()) << " faces" << endl;
     }
 
     syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
@@ -550,9 +550,8 @@ void Foam::refinementHistory::apply
 
     if (refinementHistory::debug)
     {
-        reduce(nChanged, sumOp<label>());
-        Info<< type() << " : changed decomposition on " << nChanged
-            << " cells" << endl;
+        Info<< type() << " : changed decomposition on "
+            << returnReduce(nChanged, sumOp<label>()) << " cells" << endl;
     }
 }
 
@@ -572,7 +571,7 @@ Foam::refinementHistory::refinementHistory(const IOobject& io)
     // When running in redistributePar + READ_IF_PRESENT it can happen
     // that some processors do have refinementHistory and some don't so
     // test for active has to be outside of above condition.
-    active_ = (returnReduce(visibleCells_.size(), sumOp<label>()) > 0);
+    active_ = returnReduceOr(visibleCells_.size());
 
     if (debug)
     {
@@ -645,7 +644,7 @@ Foam::refinementHistory::refinementHistory
         }
     }
 
-    active_ = (returnReduce(visibleCells_.size(), sumOp<label>()) > 0);
+    active_ = returnReduceOr(visibleCells_.size());
 
 
     // Check indices.
@@ -843,7 +842,7 @@ Foam::refinementHistory::refinementHistory(const IOobject& io, Istream& is)
     freeSplitCells_(),
     visibleCells_(is)
 {
-    active_ = (returnReduce(visibleCells_.size(), sumOp<label>()) > 0);
+    active_ = returnReduceOr(visibleCells_.size());
 
     // Check indices.
     checkIndices();
@@ -1673,7 +1672,7 @@ bool Foam::refinementHistory::read()
     bool ok = readData(readStream(typeName));
     close();
 
-    active_ = (returnReduce(visibleCells_.size(), sumOp<label>()) > 0);
+    active_ = returnReduceOr(visibleCells_.size());
 
     return ok;
 }
diff --git a/src/engine/engineMesh/engineMesh/engineMesh.C b/src/engine/engineMesh/engineMesh/engineMesh.C
index 39bc5fce78..f707abcfd3 100644
--- a/src/engine/engineMesh/engineMesh/engineMesh.C
+++ b/src/engine/engineMesh/engineMesh/engineMesh.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -72,25 +73,21 @@ Foam::engineMesh::engineMesh(const IOobject& io)
         }
     }
 
-    reduce(foundPiston, orOp<bool>());
-    reduce(foundLiner, orOp<bool>());
-    reduce(foundCylinderHead, orOp<bool>());
-
-    if (!foundPiston)
+    if (!returnReduceOr(foundPiston))
     {
         FatalErrorInFunction
             << "cannot find piston patch"
             << exit(FatalError);
     }
 
-    if (!foundLiner)
+    if (!returnReduceOr(foundLiner))
     {
         FatalErrorInFunction
             << "cannot find liner patch"
             << exit(FatalError);
     }
 
-    if (!foundCylinderHead)
+    if (!returnReduceOr(foundCylinderHead))
     {
         FatalErrorInFunction
             << "cannot find cylinderHead patch"
diff --git a/src/finiteArea/faMesh/faBoundaryMesh/faBoundaryMesh.C b/src/finiteArea/faMesh/faBoundaryMesh/faBoundaryMesh.C
index a93ec4adfc..5d5aca4d9e 100644
--- a/src/finiteArea/faMesh/faBoundaryMesh/faBoundaryMesh.C
+++ b/src/finiteArea/faMesh/faBoundaryMesh/faBoundaryMesh.C
@@ -724,9 +724,7 @@ bool Foam::faBoundaryMesh::checkParallelSync(const bool report) const
     }
 
     // Reduce (not broadcast) to respect local out-of-order errors (first loop)
-    reduce(hasError, orOp<bool>());
-
-    return hasError;
+    return returnReduceOr(hasError);
 }
 
 
diff --git a/src/finiteArea/faMesh/faMeshPatches.C b/src/finiteArea/faMesh/faMeshPatches.C
index 5cf1cc66ac..2e8170db49 100644
--- a/src/finiteArea/faMesh/faMeshPatches.C
+++ b/src/finiteArea/faMesh/faMeshPatches.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2017 Wikki Ltd
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -287,8 +287,8 @@ Foam::faPatchList Foam::faMesh::createPatchList
         patchDefsUsed.insert(bestPatchDefi);
     }
 
-    // Remove undefPatchIndex if not actually needed
-    if (!returnReduce(patchDefsUsed.found(undefPatchIndex), orOp<bool>()))
+    // Remove undefPatchIndex if not actually needed anywhere
+    if (!returnReduceOr(patchDefsUsed.found(undefPatchIndex)))
     {
         faPatchDefs.remove(undefPatchIndex);
     }
@@ -330,7 +330,7 @@ Foam::faPatchList Foam::faMesh::createPatchList
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) > 0)
+        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
         {
             // Report directly as Info, not InfoInFunction
             // since it can also be an expected result when
diff --git a/src/finiteArea/faMesh/faMeshTools/faMeshTools.C b/src/finiteArea/faMesh/faMeshTools/faMeshTools.C
index b7bbf8b90d..cf825a0f40 100644
--- a/src/finiteArea/faMesh/faMeshTools/faMeshTools.C
+++ b/src/finiteArea/faMesh/faMeshTools/faMeshTools.C
@@ -187,7 +187,7 @@ Foam::autoPtr<Foam::faMesh> Foam::faMeshTools::newMesh
 
     // Some processors without patches? - add patches
 
-    if (returnReduce(mesh.boundary().empty(), orOp<bool>()))
+    if (returnReduceOr(mesh.boundary().empty()))
     {
         // Use patchEntries, which were read on master and broadcast
 
diff --git a/src/finiteArea/faMesh/faMeshTopology.C b/src/finiteArea/faMesh/faMeshTopology.C
index 752e6b286c..3a8417a57d 100644
--- a/src/finiteArea/faMesh/faMeshTopology.C
+++ b/src/finiteArea/faMesh/faMeshTopology.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -165,7 +165,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) > 0)
+        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
         {
             edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
 
@@ -263,7 +263,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) > 0)
+        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
         {
             FatalErrorInFunction
                 << "Had " << nBadEdges
@@ -502,7 +502,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
         }
     }
 
-    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) > 0)
+    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
     {
         FatalErrorInFunction
             << "Had " << nBadEdges << " coupled boundary edges"
@@ -623,7 +623,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
     }
 
     // Verbose report of missing edges
-    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) > 0)
+    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
     {
         edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
 
diff --git a/src/finiteVolume/cfdTools/general/MRF/MRFZone.C b/src/finiteVolume/cfdTools/general/MRF/MRFZone.C
index 18b12dfceb..90e91ede07 100644
--- a/src/finiteVolume/cfdTools/general/MRF/MRFZone.C
+++ b/src/finiteVolume/cfdTools/general/MRF/MRFZone.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -593,11 +593,7 @@ bool Foam::MRFZone::read(const dictionary& dict)
             excludedPatchLabels_[i++] = patchi;
         }
 
-        bool cellZoneFound = (cellZoneID_ != -1);
-
-        reduce(cellZoneFound, orOp<bool>());
-
-        if (!cellZoneFound)
+        if (!returnReduceOr(cellZoneID_ != -1))
         {
             FatalErrorInFunction
                 << "cannot find MRF cellZone " << cellZoneName_
diff --git a/src/finiteVolume/cfdTools/general/porosityModel/porosityModel/porosityModel.C b/src/finiteVolume/cfdTools/general/porosityModel/porosityModel/porosityModel.C
index beac5ec969..283e46f9ae 100644
--- a/src/finiteVolume/cfdTools/general/porosityModel/porosityModel/porosityModel.C
+++ b/src/finiteVolume/cfdTools/general/porosityModel/porosityModel/porosityModel.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2017 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -109,10 +109,7 @@ Foam::porosityModel::porosityModel
 
     Info<< "    creating porous zone: " << zoneName_ << endl;
 
-    bool foundZone = !cellZoneIDs_.empty();
-    reduce(foundZone, orOp<bool>());
-
-    if (!foundZone && Pstream::master())
+    if (returnReduceAnd(cellZoneIDs_.empty()) && Pstream::master())
     {
         FatalErrorInFunction
             << "Cannot find porous cellZone " << zoneName_ << endl
diff --git a/src/finiteVolume/expressions/base/fvExprDriverTemplates.C b/src/finiteVolume/expressions/base/fvExprDriverTemplates.C
index 0e0940bf6c..dc7030a5ac 100644
--- a/src/finiteVolume/expressions/base/fvExprDriverTemplates.C
+++ b/src/finiteVolume/expressions/base/fvExprDriverTemplates.C
@@ -58,8 +58,7 @@ bool Foam::expressions::fvExprDriver::isGlobalVariable
     // Do size checking if requested
     if (good && expectedSize >= 0)
     {
-        good = (result.size() == expectedSize);
-        reduce(good, andOp<bool>());
+        good = returnReduceAnd(result.size() == expectedSize);
 
         if (debug && !good)
         {
@@ -103,7 +102,7 @@ Foam::expressions::fvExprDriver::getVariable
         if
         (
             expectedSize < 0
-         || returnReduce((vals.size() == expectedSize), andOp<bool>())
+         || returnReduceAnd(vals.size() == expectedSize)
         )
         {
             // Return a copy of the field
@@ -318,7 +317,7 @@ Foam::tmp<GeomField> Foam::expressions::fvExprDriver::getOrReadFieldImpl
             Pout<< "sizes: " << vals.size() << ' ' << fld.size() << endl;
         }
 
-        if (returnReduce((vals.size() == fld.size()), andOp<bool>()))
+        if (returnReduceAnd(vals.size() == fld.size()))
         {
             fld.primitiveFieldRef() = vals;
         }
diff --git a/src/finiteVolume/expressions/patch/patchExprDriverTemplates.C b/src/finiteVolume/expressions/patch/patchExprDriverTemplates.C
index f2043dc794..d49a2d800d 100644
--- a/src/finiteVolume/expressions/patch/patchExprDriverTemplates.C
+++ b/src/finiteVolume/expressions/patch/patchExprDriverTemplates.C
@@ -58,7 +58,7 @@ Foam::expressions::patchExpr::parseDriver::getVariableIfAvailable
 
         const label len = (hasPointData ? this->pointSize() : this->size());
 
-        if (returnReduce((vals.size() == len), andOp<bool>()))
+        if (returnReduceAnd(vals.size() == len))
         {
             // Return a copy of the field
             return tmp<Field<Type>>::New(vals);
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/mappedField/Sampled/Sampled.C b/src/finiteVolume/fields/fvPatchFields/derived/mappedField/Sampled/Sampled.C
index 065041a3b0..144c54aff9 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/mappedField/Sampled/Sampled.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/mappedField/Sampled/Sampled.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -278,7 +278,7 @@ Foam::PatchFunction1Types::Sampled<Type>::value
 
     // Enforce average. Either by scaling (if scaling factor > 0.5) or by
     // offsetting.
-    if (setAverage_ && returnReduce(newValues.size(), sumOp<label>()))
+    if (setAverage_ && returnReduceOr(newValues.size()))
     {
         Type averagePsi;
         if (this->faceValues())
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/swirlFanVelocity/swirlFanVelocityFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/derived/swirlFanVelocity/swirlFanVelocityFvPatchField.C
index 85029c330b..5a576a98d0 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/swirlFanVelocity/swirlFanVelocityFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/swirlFanVelocity/swirlFanVelocityFvPatchField.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -161,7 +161,7 @@ Foam::swirlFanVelocityFvPatchField::swirlFanVelocityFvPatchField
         dict.getOrDefault
         (
             "origin",
-            returnReduce(patch().size(), maxOp<label>())
+            returnReduceOr(patch().size())
           ? gSum(patch().Cf()*patch().magSf())/gSum(patch().magSf())
           : Zero
         )
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/swirlFlowRateInletVelocity/swirlFlowRateInletVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/swirlFlowRateInletVelocity/swirlFlowRateInletVelocityFvPatchVectorField.C
index 4ad0e8cf06..c0c37d2d9c 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/swirlFlowRateInletVelocity/swirlFlowRateInletVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/swirlFlowRateInletVelocity/swirlFlowRateInletVelocityFvPatchVectorField.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -68,7 +68,7 @@ swirlFlowRateInletVelocityFvPatchVectorField
         dict.getOrDefault
         (
             "origin",
-            returnReduce(patch().size(), maxOp<label>())
+            returnReduceOr(patch().size())
           ? gSum(patch().Cf()*patch().magSf())/gSum(patch().magSf())
           : Zero
         )
@@ -78,7 +78,7 @@ swirlFlowRateInletVelocityFvPatchVectorField
         dict.getOrDefault
         (
             "axis",
-            returnReduce(patch().size(), maxOp<label>())
+            returnReduceOr(patch().size())
           ? -gSum(patch().Sf())/gSum(patch().magSf())
           : Zero
         )
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/turbulentDFSEMInlet/turbulentDFSEMInletFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/turbulentDFSEMInlet/turbulentDFSEMInletFvPatchVectorField.C
index b31a781d3a..d618ec946b 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/turbulentDFSEMInlet/turbulentDFSEMInletFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/turbulentDFSEMInlet/turbulentDFSEMInletFvPatchVectorField.C
@@ -190,8 +190,10 @@ void Foam::turbulentDFSEMInletFvPatchVectorField::initialisePatch()
     patchBounds_.inflate(0.1);
 
     // Determine if all eddies spawned from a single processor
-    singleProc_ = patch.size() == returnReduce(patch.size(), sumOp<label>());
-    reduce(singleProc_, orOp<bool>());
+    singleProc_ = returnReduceOr
+    (
+        patch.size() == returnReduce(patch.size(), sumOp<label>())
+    );
 }
 
 
@@ -1031,8 +1033,8 @@ void Foam::turbulentDFSEMInletFvPatchVectorField::updateCoeffs()
         {
             Info<< "Magnitude of bulk velocity: " << UBulk << endl;
 
-            label n = eddies_.size();
-            Info<< "Number of eddies: " << returnReduce(n, sumOp<label>())
+            Info<< "Number of eddies: "
+                << returnReduce(eddies_.size(), sumOp<label>())
                 << endl;
 
             Info<< "Patch:" << patch().patch().name()
diff --git a/src/finiteVolume/fvMesh/fvGeometryScheme/solidBody/solidBodyFvGeometryScheme.C b/src/finiteVolume/fvMesh/fvGeometryScheme/solidBody/solidBodyFvGeometryScheme.C
index 74a8e66c63..1898dbe506 100644
--- a/src/finiteVolume/fvMesh/fvGeometryScheme/solidBody/solidBodyFvGeometryScheme.C
+++ b/src/finiteVolume/fvMesh/fvGeometryScheme/solidBody/solidBodyFvGeometryScheme.C
@@ -81,7 +81,7 @@ void Foam::solidBodyFvGeometryScheme::setMeshMotionData()
             << endl;
 
         // Quick return if no points have moved
-        if (returnReduce(changedPoints.none(), andOp<label>()))
+        if (returnReduceAnd(changedPoints.none()))
         {
             return;
         }
diff --git a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetProxy.C b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetProxy.C
index 3c4cb75a38..302357e8ba 100644
--- a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetProxy.C
+++ b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetProxy.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -200,7 +200,7 @@ bool Foam::fvMeshSubsetProxy::correct(bool verbose)
         subsetter_.reset(selectedCells_, exposedPatchId_);
     }
 
-    return returnReduce(changed, orOp<bool>());
+    return returnReduceOr(changed);
 }
 
 
diff --git a/src/finiteVolume/fvMesh/fvMeshTools/fvMeshTools.C b/src/finiteVolume/fvMesh/fvMeshTools/fvMeshTools.C
index 565c8a9223..d42c207e20 100644
--- a/src/finiteVolume/fvMesh/fvMeshTools/fvMeshTools.C
+++ b/src/finiteVolume/fvMesh/fvMeshTools/fvMeshTools.C
@@ -597,7 +597,7 @@ Foam::fvMeshTools::newMesh
 
     // Some processors without patches? - add patches
 
-    if (returnReduce(mesh.boundary().empty(), orOp<bool>()))
+    if (returnReduceOr(mesh.boundary().empty()))
     {
         DynamicList<polyPatch*> newPatches(patchEntries.size());
 
diff --git a/src/finiteVolume/interpolation/volPointInterpolation/volPointInterpolation.C b/src/finiteVolume/interpolation/volPointInterpolation/volPointInterpolation.C
index 9200d9c1fd..9b2dd90aad 100644
--- a/src/finiteVolume/interpolation/volPointInterpolation/volPointInterpolation.C
+++ b/src/finiteVolume/interpolation/volPointInterpolation/volPointInterpolation.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -58,8 +58,7 @@ bool Foam::volPointInterpolation::hasSeparated(const pointMesh& pMesh)
         }
     }
 
-    reduce(hasSpecial, orOp<bool>());
-    return hasSpecial;
+    return returnReduceOr(hasSpecial);
 }
 
 
diff --git a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
index 11c1960245..6147c65fb9 100644
--- a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
+++ b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C
@@ -156,7 +156,7 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setFaceZoneFaces()
 
     // Could also check this
     #if 0
-    if (!returnReduce(bool(numFaces), orOp<bool>()))
+    if (!returnReduceOr(numFaces))
     {
         WarningInFunction
             << type() << ' ' << name() << ": "
@@ -314,7 +314,7 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setPatchFaces()
 
     // Could also check this
     #if 0
-    if (!returnReduce(bool(numFaces), orOp<bool>()))
+    if (!returnReduceOr(numFaces))
     {
         WarningInFunction
             << type() << ' ' << name() << ": "
@@ -807,7 +807,7 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::weightingFactor
     // scalar * unit-normal
 
     // Can skip this check - already used canWeight()
-    /// if (returnReduce(weightField.empty(), andOp<bool>()))
+    /// if (returnReduceAnd(weightField.empty()))
     /// {
     ///     // No weight field - revert to unweighted form?
     ///     return tmp<scalarField>::New(Sf.size(), scalar(1));
@@ -835,7 +835,7 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::areaWeightingFactor
     // scalar * Area
 
     // Can skip this check - already used canWeight()
-    /// if (returnReduce(weightField.empty(), andOp<bool>()))
+    /// if (returnReduceAnd(weightField.empty()))
     /// {
     ///     // No weight field - revert to unweighted form
     ///     return mag(Sf);
@@ -862,7 +862,7 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::weightingFactor
     // vector (dot) unit-normal
 
     // Can skip this check - already used canWeight()
-    /// if (returnReduce(weightField.empty(), andOp<bool>()))
+    /// if (returnReduceAnd(weightField.empty()))
     /// {
     ///     // No weight field - revert to unweighted form
     ///     return tmp<scalarField>::New(Sf.size(), scalar(1));
@@ -903,7 +903,7 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::areaWeightingFactor
     // vector (dot) Area
 
     // Can skip this check - already used canWeight()
-    /// if (returnReduce(weightField.empty(), andOp<bool>()))
+    /// if (returnReduceAnd(weightField.empty()))
     /// {
     ///     // No weight field - revert to unweighted form
     ///     return mag(Sf);
@@ -1297,7 +1297,7 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::write()
 
 
     // Process the fields
-    if (returnReduce(!vectorWeights.empty(), orOp<bool>()))
+    if (returnReduceOr(!vectorWeights.empty()))
     {
         if (scalarWeights.size())
         {
diff --git a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValueTemplates.C b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValueTemplates.C
index 5731d52be3..3455b2de97 100644
--- a/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValueTemplates.C
+++ b/src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValueTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -60,7 +60,7 @@ inline bool Foam::functionObjects::fieldValues::surfaceFieldValue::canWeight
 ) const
 {
     // Non-empty on some processor
-    return returnReduce(!fld.empty(), orOp<bool>());
+    return returnReduceOr(!fld.empty());
 }
 
 
diff --git a/src/functionObjects/field/fieldValues/volFieldValue/volFieldValueI.H b/src/functionObjects/field/fieldValues/volFieldValue/volFieldValueI.H
index 9fdc6fb090..4ec613c5c1 100644
--- a/src/functionObjects/field/fieldValues/volFieldValue/volFieldValueI.H
+++ b/src/functionObjects/field/fieldValues/volFieldValue/volFieldValueI.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -49,7 +49,7 @@ inline bool Foam::functionObjects::fieldValues::volFieldValue::canWeight
 ) const
 {
     // Non-empty on some processor
-    return returnReduce(!fld.empty(), orOp<bool>());
+    return returnReduceOr(!fld.empty());
 }
 
 
diff --git a/src/functionObjects/field/reference/reference.C b/src/functionObjects/field/reference/reference.C
index e3e4168337..0846198f21 100644
--- a/src/functionObjects/field/reference/reference.C
+++ b/src/functionObjects/field/reference/reference.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -54,7 +54,7 @@ bool Foam::functionObjects::reference::calc()
 
     Log << endl;
 
-    return returnReduce(processed, orOp<bool>());
+    return returnReduceOr(processed);
 }
 
 
diff --git a/src/functionObjects/field/zeroGradient/zeroGradientTemplates.C b/src/functionObjects/field/zeroGradient/zeroGradientTemplates.C
index 7db327215b..8f87143e50 100644
--- a/src/functionObjects/field/zeroGradient/zeroGradientTemplates.C
+++ b/src/functionObjects/field/zeroGradient/zeroGradientTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -70,7 +70,7 @@ int Foam::functionObjects::zeroGradient::apply
 
     const VolFieldType& input = lookupObject<VolFieldType>(inputName);
 
-    if (!returnReduce(accept(input), orOp<bool>()))
+    if (!returnReduceOr(accept(input)))
     {
         state = -1;
         return state;
diff --git a/src/functionObjects/lagrangian/dataCloud/dataCloud.C b/src/functionObjects/lagrangian/dataCloud/dataCloud.C
index c7ec4df888..d176ab13df 100644
--- a/src/functionObjects/lagrangian/dataCloud/dataCloud.C
+++ b/src/functionObjects/lagrangian/dataCloud/dataCloud.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -82,7 +82,7 @@ bool Foam::functionObjects::dataCloud::writeCloud
     }
 
     applyFilter_ = calculateFilter(obrTmp, log);
-    reduce(applyFilter_, orOp<bool>());
+    Pstream::reduceOr(applyFilter_);
 
 
     // Number of parcels (locally)
diff --git a/src/functionObjects/lagrangian/dataCloud/dataCloudTemplates.C b/src/functionObjects/lagrangian/dataCloud/dataCloudTemplates.C
index b1ef6f3093..d2b6e16b13 100644
--- a/src/functionObjects/lagrangian/dataCloud/dataCloudTemplates.C
+++ b/src/functionObjects/lagrangian/dataCloud/dataCloudTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -188,7 +188,7 @@ bool Foam::functionObjects::dataCloud::writeField
     const List<Type>* fldPtr = obrTmp.findObject<IOField<Type>>(fieldName_);
     const List<Type>& values = (fldPtr ? *fldPtr : List<Type>());
 
-    if (!returnReduce((fldPtr != nullptr), orOp<bool>()))
+    if (!returnReduceOr(fldPtr != nullptr))
     {
         return false;
     }
diff --git a/src/functionObjects/lagrangian/dsmcFields/dsmcFields.C b/src/functionObjects/lagrangian/dsmcFields/dsmcFields.C
index 29b3eec177..05ca302db7 100644
--- a/src/functionObjects/lagrangian/dsmcFields/dsmcFields.C
+++ b/src/functionObjects/lagrangian/dsmcFields/dsmcFields.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -157,7 +157,7 @@ bool Foam::functionObjects::dsmcFields::write()
                 Member##Ptr = obr_.cfindObject<FieldType>(fldName);            \
             }                                                                  \
                                                                                \
-            if (returnReduce(!Member##Ptr, orOp<bool>()))                      \
+            if (returnReduceOr(!Member##Ptr))                                  \
             {                                                                  \
                 Log << type() << ' ' << name() << " : no " << Name             \
                     << " field found - not calculating\n";                     \
diff --git a/src/functionObjects/lagrangian/vtkCloud/vtkCloud.C b/src/functionObjects/lagrangian/vtkCloud/vtkCloud.C
index 3709429dcb..108f3cc22d 100644
--- a/src/functionObjects/lagrangian/vtkCloud/vtkCloud.C
+++ b/src/functionObjects/lagrangian/vtkCloud/vtkCloud.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -131,7 +131,7 @@ bool Foam::functionObjects::vtkCloud::writeCloud
     }
 
     applyFilter_ = calculateFilter(obrTmp, log);
-    reduce(applyFilter_, orOp<bool>());
+    Pstream::reduceOr(applyFilter_);
 
 
     // Number of parcels (locally)
diff --git a/src/fvAgglomerationMethods/pairPatchAgglomeration/pairPatchAgglomeration.C b/src/fvAgglomerationMethods/pairPatchAgglomeration/pairPatchAgglomeration.C
index 78ff09b9f5..d1e2faf2ec 100644
--- a/src/fvAgglomerationMethods/pairPatchAgglomeration/pairPatchAgglomeration.C
+++ b/src/fvAgglomerationMethods/pairPatchAgglomeration/pairPatchAgglomeration.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -57,7 +57,7 @@ bool Foam::pairPatchAgglomeration::continueAgglomerating
 
     return
     (
-        returnReduce(nLocal > nFacesInCoarsestLevel_, orOp<bool>())
+        returnReduceOr(nLocal > nFacesInCoarsestLevel_)
      || nGlobal > nGlobalFacesInCoarsestLevel_
     )
     && nGlobal != nGlobalOld;
diff --git a/src/fvOptions/cellSetOption/cellSetOption.C b/src/fvOptions/cellSetOption/cellSetOption.C
index a5844021ef..beb3a66377 100644
--- a/src/fvOptions/cellSetOption/cellSetOption.C
+++ b/src/fvOptions/cellSetOption/cellSetOption.C
@@ -180,7 +180,7 @@ void Foam::fv::cellSetOption::setCellSelection()
                     selectedCells.insert(celli);
                 }
 
-                if (!returnReduce(found, orOp<bool>()))
+                if (!returnReduceOr(found))
                 {
                     WarningInFunction
                         << "No owner cell found for point " << p << endl;
diff --git a/src/fvOptions/corrections/limitTemperature/limitTemperature.C b/src/fvOptions/corrections/limitTemperature/limitTemperature.C
index e41c645251..1a8fad4b50 100644
--- a/src/fvOptions/corrections/limitTemperature/limitTemperature.C
+++ b/src/fvOptions/corrections/limitTemperature/limitTemperature.C
@@ -212,7 +212,7 @@ void Foam::fv::limitTemperature::correct(volScalarField& he)
     }
 
 
-    if (returnReduce(changedValues, orOp<bool>()))
+    if (returnReduceOr(changedValues))
     {
         // We've changed internal values so give
         // boundary conditions opportunity to correct
diff --git a/src/fvOptions/sources/derived/actuationDiskSource/actuationDiskSource.C b/src/fvOptions/sources/derived/actuationDiskSource/actuationDiskSource.C
index 11da05cfc3..5ecac54e41 100644
--- a/src/fvOptions/sources/derived/actuationDiskSource/actuationDiskSource.C
+++ b/src/fvOptions/sources/derived/actuationDiskSource/actuationDiskSource.C
@@ -130,7 +130,7 @@ void Foam::fv::actuationDiskSource::setMonitorCells(const dictionary& dict)
                     selectedCells.insert(celli);
                 }
 
-                if (!returnReduce(found, orOp<bool>()))
+                if (!returnReduceOr(found))
                 {
                     WarningInFunction
                         << "No owner cell found for point "
diff --git a/src/lagrangian/DSMC/submodels/InflowBoundaryModel/FreeStream/FreeStream.C b/src/lagrangian/DSMC/submodels/InflowBoundaryModel/FreeStream/FreeStream.C
index 21e6d47839..12fd8ab036 100644
--- a/src/lagrangian/DSMC/submodels/InflowBoundaryModel/FreeStream/FreeStream.C
+++ b/src/lagrangian/DSMC/submodels/InflowBoundaryModel/FreeStream/FreeStream.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -406,10 +407,8 @@ void Foam::FreeStream<CloudType>::inflow()
         }
     }
 
-    reduce(particlesInserted, sumOp<label>());
-
     Info<< "    Particles inserted              = "
-        << particlesInserted << endl;
+        << returnReduce(particlesInserted, sumOp<label>()) << endl;
 
 }
 
diff --git a/src/lagrangian/basic/Cloud/Cloud.C b/src/lagrangian/basic/Cloud/Cloud.C
index 73f57fb1cc..28a8a56338 100644
--- a/src/lagrangian/basic/Cloud/Cloud.C
+++ b/src/lagrangian/basic/Cloud/Cloud.C
@@ -273,7 +273,7 @@ void Foam::Cloud<ParticleType>::move
 
         pBufs.finishedNeighbourSends(neighbourProcs);
 
-        if (!returnReduce(pBufs.hasRecvData(), orOp<bool>()))
+        if (!returnReduceOr(pBufs.hasRecvData()))
         {
             // No parcels to transfer
             break;
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
index 76f3b7b654..6413a68b9b 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -384,7 +384,7 @@ inline Foam::scalar Foam::ThermoCloud<CloudType>::Tmax() const
         nonEmpty = true;
     }
 
-    if (returnReduce(nonEmpty, orOp<bool>()))
+    if (returnReduceOr(nonEmpty))
     {
         return returnReduce(val, maxOp<scalar>());
     }
@@ -405,7 +405,7 @@ inline Foam::scalar Foam::ThermoCloud<CloudType>::Tmin() const
         nonEmpty = true;
     }
 
-    if (returnReduce(nonEmpty, orOp<bool>()))
+    if (returnReduceOr(nonEmpty))
     {
         return returnReduce(val, minOp<scalar>());
     }
diff --git a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
index f12c59d816..76e671640b 100644
--- a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
+++ b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
@@ -73,7 +73,7 @@ bool Foam::ensightOutput::writeCloudField
     ensightFile& os
 )
 {
-    if (returnReduce(field.empty(), andOp<bool>()))
+    if (returnReduceAnd(field.empty()))
     {
         return false;
     }
diff --git a/src/lagrangian/intermediate/conversion/vtk/foamVtkLagrangianWriterTemplates.C b/src/lagrangian/intermediate/conversion/vtk/foamVtkLagrangianWriterTemplates.C
index 32c4ee18e3..b357544ac8 100644
--- a/src/lagrangian/intermediate/conversion/vtk/foamVtkLagrangianWriterTemplates.C
+++ b/src/lagrangian/intermediate/conversion/vtk/foamVtkLagrangianWriterTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -99,14 +99,7 @@ Foam::label Foam::vtk::lagrangianWriter::writeFields
         );
 
         // Check global existence to avoid any errors
-        const bool ok =
-            returnReduce
-            (
-                io.typeHeaderOk<IOField<Type>>(false),
-                orOp<bool>()
-            );
-
-        if (!ok)
+        if (!returnReduceOr(io.typeHeaderOk<IOField<Type>>(false)))
         {
             continue;
         }
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/PatchInteractionModel/RecycleInteraction/RecycleInteraction.C b/src/lagrangian/intermediate/submodels/Kinematic/PatchInteractionModel/RecycleInteraction/RecycleInteraction.C
index 1b42f0c21c..d8d28820a4 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/PatchInteractionModel/RecycleInteraction/RecycleInteraction.C
+++ b/src/lagrangian/intermediate/submodels/Kinematic/PatchInteractionModel/RecycleInteraction/RecycleInteraction.C
@@ -246,7 +246,7 @@ void Foam::RecycleInteraction<CloudType>::postEvolve()
 
         pBufs.finishedSends();
 
-        if (!returnReduce(pBufs.hasRecvData(), orOp<bool>()))
+        if (!returnReduceOr(pBufs.hasRecvData()))
         {
             // No parcels to recycle
             return;
diff --git a/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C b/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
index 97e67f7553..d462e162d0 100644
--- a/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
+++ b/src/mesh/snappyHexMesh/externalDisplacementMeshMover/medialAxisMeshMover.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2014-2015 OpenFOAM Foundation
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -727,7 +727,7 @@ void Foam::medialAxisMeshMover::syncPatchDisplacement
     const indirectPrimitivePatch& pp = adaptPatchPtr_();
     const labelList& meshPoints = pp.meshPoints();
 
-    label nChangedTotal = 0;
+    //label nChangedTotal = 0;
 
     while (true)
     {
@@ -819,9 +819,9 @@ void Foam::medialAxisMeshMover::syncPatchDisplacement
         //    }
         //}
 
-        nChangedTotal += nChanged;
+        //nChangedTotal += nChanged;
 
-        if (!returnReduce(nChanged, sumOp<label>()))
+        if (!returnReduceOr(nChanged))
         {
             break;
         }
@@ -1148,7 +1148,7 @@ void Foam::medialAxisMeshMover::findIsolatedRegions
         }
 
 
-        if (returnReduce(nChanged, sumOp<label>()) == 0)
+        if (!returnReduceOr(nChanged))
         {
             break;
         }
@@ -1238,10 +1238,9 @@ void Foam::medialAxisMeshMover::findIsolatedRegions
         }
     }
 
-    reduce(nPointCounter, sumOp<label>());
     Info<< typeName
-        << " : Number of isolated points extrusion stopped : "<< nPointCounter
-        << endl;
+        << " : Number of isolated points extrusion stopped : "
+        << returnReduce(nPointCounter, sumOp<label>()) << endl;
 }
 
 
@@ -1558,9 +1557,8 @@ void Foam::medialAxisMeshMover::calculateDisplacement
         }
     }
 
-    reduce(numThicknessRatioExclude, sumOp<label>());
     Info<< typeName << " : Reducing layer thickness at "
-        << numThicknessRatioExclude
+        << returnReduce(numThicknessRatioExclude, sumOp<label>())
         << " nodes where thickness to medial axis distance is large " << endl;
 
 
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
index 3122030b02..92e3ffe0b5 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
@@ -353,8 +353,8 @@ void Foam::meshRefinement::updateIntersections(const labelList& changedFaces)
     bitSet isMasterFace(syncTools::getMasterFaces(mesh_));
 
     {
-        label nMasterFaces = isMasterFace.count();
-        reduce(nMasterFaces, sumOp<label>());
+        const label nMasterFaces =
+            returnReduce(isMasterFace.count(), sumOp<label>());
 
         label nChangedFaces = 0;
         forAll(changedFaces, i)
@@ -423,9 +423,7 @@ void Foam::meshRefinement::updateIntersections(const labelList& changedFaces)
     // case in general since same vectors but just to make sure.
     syncTools::syncFaceList(mesh_, surfaceIndex_, maxEqOp<label>());
 
-    label nHits = countHits();
-    label nTotHits = returnReduce(nHits, sumOp<label>());
-
+    label nTotHits = returnReduce(countHits(), sumOp<label>());
 
     if (!dryRun_)
     {
@@ -2780,7 +2778,8 @@ Foam::label Foam::meshRefinement::findCell
     (void)mesh.tetBasePtIs();
 
     label celli = mesh.findCell(p, findCellMode);
-    if (returnReduce(celli, maxOp<label>()) == -1)
+
+    if (returnReduceAnd(celli < 0))
     {
         // See if we can perturb a bit
         celli = mesh.findCell(p+perturbVec, findCellMode);
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBaffles.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBaffles.C
index 152ab78853..5106cce0fb 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBaffles.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBaffles.C
@@ -597,7 +597,7 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::createBaffles
 
 
     autoPtr<mapPolyMesh> mapPtr;
-    if (returnReduce(nBaffles, sumOp<label>()))
+    if (returnReduceOr(nBaffles))
     {
         // Remove any unnecessary fields
         mesh_.clearOut();
@@ -818,7 +818,6 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::createZoneBaffles
 
         label nLocalBaffles = sum(nBaffles);
 
-
         label nTotalBaffles = returnReduce(nLocalBaffles, sumOp<label>());
 
         if (nTotalBaffles > 0)
@@ -1194,7 +1193,7 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::mergeBaffles
 {
     autoPtr<mapPolyMesh> mapPtr;
 
-    if (returnReduce(couples.size()+faceToPatch.size(), sumOp<label>()))
+    if (returnReduceOr(couples.size() || faceToPatch.size()))
     {
         // Mesh change engine
         polyTopoChange meshMod(mesh_);
@@ -1401,7 +1400,7 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::mergeZoneBaffles
     );
 
     autoPtr<mapPolyMesh> mapPtr;
-    if (returnReduce(zoneBaffles.size(), sumOp<label>()))
+    if (returnReduceOr(zoneBaffles.size()))
     {
         mapPtr = mergeBaffles(zoneBaffles, Map<label>(0));
     }
@@ -2077,7 +2076,7 @@ void Foam::meshRefinement::findCellZoneTopo
             }
         }
 
-        if (!returnReduce(changed, orOp<bool>()))
+        if (!returnReduceOr(changed))
         {
             break;
         }
@@ -3212,8 +3211,8 @@ void Foam::meshRefinement::zonify
 
         if (debug)
         {
-            const pointZone& pz = pointZones[zonei];
             mkDir(mesh_.time().timePath());
+            const pointZone& pz = pointZones[zonei];
             OBJstream str(mesh_.time().timePath()/pz.name()+".obj");
             Pout<< "Writing " << pz.size() << " frozen points to "
                 << str.name() << endl;
@@ -3222,8 +3221,7 @@ void Foam::meshRefinement::zonify
                 str.write(mesh_.points()[pointi]);
             }
         }
-
-        if (debug && returnReduce(unnamedClosureFaces.size(), sumOp<label>()))
+        if (debug && returnReduceOr(unnamedClosureFaces.size()))
         {
             mkDir(mesh_.time().timePath());
             OBJstream str(mesh_.time().timePath()/"unnamedClosureFaces.obj");
@@ -3234,7 +3232,7 @@ void Foam::meshRefinement::zonify
                 str.write(mesh_.faces()[facei], mesh_.points(), false);
             }
         }
-        if (debug && returnReduce(namedClosureFaces.size(), sumOp<label>()))
+        if (debug && returnReduceOr(namedClosureFaces.size()))
         {
             mkDir(mesh_.time().timePath());
             OBJstream str(mesh_.time().timePath()/"namedClosureFaces.obj");
@@ -4036,7 +4034,7 @@ Foam::label Foam::meshRefinement::markPatchZones
         }
 
 
-        if (returnReduce(changedEdges.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(changedEdges.empty()))
         {
             break;
         }
@@ -4219,7 +4217,7 @@ void Foam::meshRefinement::consistentOrientation
         }
 
 
-        if (returnReduce(changedEdges.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(changedEdges.empty()))
         {
             break;
         }
@@ -4750,8 +4748,7 @@ void Foam::meshRefinement::mergeFreeStandingBaffles
         )
     );
 
-    label nCouples = couples.size();
-    reduce(nCouples, sumOp<label>());
+    const label nCouples = returnReduce(couples.size(), sumOp<label>());
 
     Info<< "Detected free-standing baffles : " << nCouples << endl;
 
@@ -5297,8 +5294,11 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::splitMesh
     }
     cellsToRemove.shrink();
 
-    label nCellsToKeep = mesh_.nCells() - cellsToRemove.size();
-    reduce(nCellsToKeep, sumOp<label>());
+    const label nCellsToKeep = returnReduce
+    (
+        mesh_.nCells() - cellsToRemove.size(),
+        sumOp<label>()
+    );
 
     Info<< "Keeping all cells containing inside points" << endl
         << "Selected for keeping : " << nCellsToKeep << " cells." << endl;
@@ -5541,7 +5541,7 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::mergePoints
 
     autoPtr<mapPolyMesh> mapPtr;
 
-    if (returnReduce(nPointPairs, sumOp<label>()))
+    if (returnReduceOr(nPointPairs))
     {
         Map<label> pointToMaster(2*nPointPairs);
         forAll(pointToDuplicate, pointI)
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBlock.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBlock.C
index 19520d47fd..617bf2fd98 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBlock.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementBlock.C
@@ -1408,7 +1408,7 @@ void Foam::meshRefinement::selectIntersectedFaces
 //
 //
 //    autoPtr<mapPolyMesh> mapPtr;
-//    if (returnReduce(haveLeak, orOp<bool>()))
+//    if (returnReduceOr(haveLeak))
 //    {
 //        // Use shortestPathSet to provide a minimum set of faces needed
 //        // to close hole. Tbd: maybe directly use wave?
@@ -1927,7 +1927,7 @@ Foam::autoPtr<Foam::mapPolyMesh> Foam::meshRefinement::blockLeakFaces
 
 
     autoPtr<mapPolyMesh> mapPtr;
-    if (returnReduce(haveLeak, orOp<bool>()))
+    if (returnReduceOr(haveLeak))
     {
         // Use holeToFace to provide a minimum set of faces needed
         // to close hole.
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementRefine.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementRefine.C
index e1873dca63..f4cf25096b 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinementRefine.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinementRefine.C
@@ -608,7 +608,7 @@ void Foam::meshRefinement::markFeatureCellLevel
             Pout<< "Remaining particles " << cloud.size() << endl;
         }
 
-        if (returnReduce(cloud.size(), sumOp<label>()) == 0)
+        if (!returnReduceOr(cloud.size()))
         {
             break;
         }
diff --git a/src/mesh/snappyHexMesh/refinementFeatures/refinementFeatures.C b/src/mesh/snappyHexMesh/refinementFeatures/refinementFeatures.C
index 4e5edc5ea3..1786b62341 100644
--- a/src/mesh/snappyHexMesh/refinementFeatures/refinementFeatures.C
+++ b/src/mesh/snappyHexMesh/refinementFeatures/refinementFeatures.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -632,7 +632,7 @@ bool Foam::refinementFeatures::checkSizes
         os<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
diff --git a/src/mesh/snappyHexMesh/refinementSurfaces/refinementSurfaces.C b/src/mesh/snappyHexMesh/refinementSurfaces/refinementSurfaces.C
index b62d8bd879..b36725842e 100644
--- a/src/mesh/snappyHexMesh/refinementSurfaces/refinementSurfaces.C
+++ b/src/mesh/snappyHexMesh/refinementSurfaces/refinementSurfaces.C
@@ -91,13 +91,11 @@ Foam::labelList Foam::refinementSurfaces::findHigherLevel
             }
         }
 
-        label nRetest = returnReduce(retestSet.size(), sumOp<label>());
-        if (nRetest > 0)
+        if (returnReduceOr(retestSet.size()))
         {
-            reduce(nHits, sumOp<label>());
-
-            //Info<< "Retesting " << nRetest
-            //    << " out of " << nHits
+            //Info<< "Retesting "
+            //    << returnReduce(retestSet.size(), sumOp<label>())
+            //    << " out of " << returnReduce(nHits, sumOp<label>())
             //    << " intersections on uncached elements on geometry "
             //    << geom.name() << endl;
 
@@ -1377,7 +1375,7 @@ void Foam::refinementSurfaces::findHigherIntersection
 
 
         // All done? Note that this decision should be synchronised
-        if (returnReduce(missI, sumOp<label>()) == 0)
+        if (returnReduceAnd(missI == 0))
         {
             break;
         }
diff --git a/src/mesh/snappyHexMesh/shellSurfaces/shellSurfaces.C b/src/mesh/snappyHexMesh/shellSurfaces/shellSurfaces.C
index 8a0f7aad9d..9564ec4cb9 100644
--- a/src/mesh/snappyHexMesh/shellSurfaces/shellSurfaces.C
+++ b/src/mesh/snappyHexMesh/shellSurfaces/shellSurfaces.C
@@ -186,7 +186,7 @@ void Foam::shellSurfaces::orient()
         }
     }
 
-    if (returnReduce(hasSurface, orOp<bool>()))
+    if (returnReduceOr(hasSurface))
     {
         const point outsidePt = overallBb.max() + overallBb.span();
 
diff --git a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
index a31d1a7e67..77baff46e5 100644
--- a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
+++ b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyLayerDriver.C
@@ -1779,7 +1779,7 @@ void Foam::snappyLayerDriver::syncPatchDisplacement
     const fvMesh& mesh = meshRefiner_.mesh();
     const labelList& meshPoints = pp.meshPoints();
 
-    label nChangedTotal = 0;
+    //label nChangedTotal = 0;
 
     while (true)
     {
@@ -1879,9 +1879,9 @@ void Foam::snappyLayerDriver::syncPatchDisplacement
                 }
             }
         }
-        nChangedTotal += nChanged;
+        //nChangedTotal += nChanged;
 
-        if (!returnReduce(nChanged, sumOp<label>()))
+        if (!returnReduceOr(nChanged))
         {
             break;
         }
@@ -4423,7 +4423,7 @@ void Foam::snappyLayerDriver::mapFaceZonePoints
     // Use geometric detection of points-to-be-merged
     //  - detect any boundary face created from a duplicated face (=baffle)
     //  - on these mark any point created from a duplicated point
-    if (returnReduce(pointToMaster.size(), sumOp<label>()))
+    if (returnReduceOr(pointToMaster.size()))
     {
         // Estimate number of points-to-be-merged
         DynamicList<label> candidates(baffles.size()*4);
@@ -5435,7 +5435,7 @@ void Foam::snappyLayerDriver::doLayers
 
     patchIDs.shrink();
 
-    if (returnReduce(nFacesWithLayers, sumOp<label>()) == 0)
+    if (!returnReduceOr(nFacesWithLayers))
     {
         Info<< nl << "No layers to generate ..." << endl;
     }
@@ -5506,7 +5506,7 @@ void Foam::snappyLayerDriver::doLayers
                 }
             }
 
-            reduce(faceZoneOnCoupledFace, orOp<bool>());
+            Pstream::reduceOr(faceZoneOnCoupledFace);
         }
 
 
diff --git a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyRefineDriver.C b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyRefineDriver.C
index ff5af5aedf..d0c67cef8e 100644
--- a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyRefineDriver.C
+++ b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappyRefineDriver.C
@@ -150,8 +150,8 @@ Foam::label Foam::snappyRefineDriver::featureEdgeRefine
 
 
 
-            label nCellsToRefine = cellsToRefine.size();
-            reduce(nCellsToRefine, sumOp<label>());
+            const label nCellsToRefine =
+                returnReduce(cellsToRefine.size(), sumOp<label>());
 
             Info<< "Selected for feature refinement : " << nCellsToRefine
                 << " cells (out of " << mesh.globalData().nTotalCells()
@@ -171,14 +171,7 @@ Foam::label Foam::snappyRefineDriver::featureEdgeRefine
             }
 
 
-            if
-            (
-                returnReduce
-                (
-                    (mesh.nCells() >= refineParams.maxLocalCells()),
-                    orOp<bool>()
-                )
-            )
+            if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
             {
                 meshRefiner_.balanceAndRefine
                 (
@@ -289,8 +282,8 @@ Foam::label Foam::snappyRefineDriver::smallFeatureRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -312,14 +305,7 @@ Foam::label Foam::snappyRefineDriver::smallFeatureRefine
         }
 
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -466,8 +452,8 @@ Foam::label Foam::snappyRefineDriver::surfaceOnlyRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -496,14 +482,7 @@ Foam::label Foam::snappyRefineDriver::surfaceOnlyRefine
         }
 
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -725,8 +704,8 @@ Foam::label Foam::snappyRefineDriver::gapOnlyRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -755,14 +734,7 @@ Foam::label Foam::snappyRefineDriver::gapOnlyRefine
         }
 
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -957,8 +929,8 @@ Foam::label Foam::snappyRefineDriver::bigGapOnlyRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -987,14 +959,7 @@ Foam::label Foam::snappyRefineDriver::bigGapOnlyRefine
         }
 
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -1114,8 +1079,8 @@ Foam::label Foam::snappyRefineDriver::danglingCellRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -1144,14 +1109,7 @@ Foam::label Foam::snappyRefineDriver::danglingCellRefine
         }
 
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -1466,8 +1424,8 @@ Foam::label Foam::snappyRefineDriver::refinementInterfaceRefine
                 << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-            label nCellsToRefine = cellsToRefine.size();
-            reduce(nCellsToRefine, sumOp<label>());
+            const label nCellsToRefine =
+                returnReduce(cellsToRefine.size(), sumOp<label>());
 
             Info<< "Selected for refinement : " << nCellsToRefine
                 << " cells (out of " << mesh.globalData().nTotalCells()
@@ -1496,14 +1454,7 @@ Foam::label Foam::snappyRefineDriver::refinementInterfaceRefine
             }
 
 
-            if
-            (
-                returnReduce
-                (
-                    (mesh.nCells() >= refineParams.maxLocalCells()),
-                    orOp<bool>()
-                )
-            )
+            if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
             {
                 meshRefiner_.balanceAndRefine
                 (
@@ -1721,8 +1672,8 @@ Foam::label Foam::snappyRefineDriver::boundaryRefinementInterfaceRefine
                 << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-            label nCellsToRefine = cellsToRefine.size();
-            reduce(nCellsToRefine, sumOp<label>());
+            const label nCellsToRefine =
+                returnReduce(cellsToRefine.size(), sumOp<label>());
 
             Info<< "Selected for refinement : " << nCellsToRefine
                 << " cells (out of " << mesh.globalData().nTotalCells()
@@ -1751,14 +1702,7 @@ Foam::label Foam::snappyRefineDriver::boundaryRefinementInterfaceRefine
             }
 
 
-            if
-            (
-                returnReduce
-                (
-                    (mesh.nCells() >= refineParams.maxLocalCells()),
-                    orOp<bool>()
-                )
-            )
+            if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
             {
                 meshRefiner_.balanceAndRefine
                 (
@@ -1989,8 +1933,8 @@ Foam::label Foam::snappyRefineDriver::shellRefine
             << mesh.time().cpuTimeIncrement() << " s" << endl;
 
 
-        label nCellsToRefine = cellsToRefine.size();
-        reduce(nCellsToRefine, sumOp<label>());
+        const label nCellsToRefine =
+            returnReduce(cellsToRefine.size(), sumOp<label>());
 
         Info<< "Selected for internal refinement : " << nCellsToRefine
             << " cells (out of " << mesh.globalData().nTotalCells()
@@ -2018,14 +1962,7 @@ Foam::label Foam::snappyRefineDriver::shellRefine
             const_cast<Time&>(mesh.time())++;
         }
 
-        if
-        (
-            returnReduce
-            (
-                (mesh.nCells() >= refineParams.maxLocalCells()),
-                orOp<bool>()
-            )
-        )
+        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
         {
             meshRefiner_.balanceAndRefine
             (
@@ -2148,8 +2085,8 @@ Foam::label Foam::snappyRefineDriver::directionalShellRefine
             Info<< "Determined cells to refine in = "
                 << mesh.time().cpuTimeIncrement() << " s" << endl;
 
-            label nCellsToRefine = cellsToRefine.size();
-            reduce(nCellsToRefine, sumOp<label>());
+            const label nCellsToRefine =
+                returnReduce(cellsToRefine.size(), sumOp<label>());
 
             Info<< "Selected for direction " << vector::componentNames[dir]
                 << " refinement : " << nCellsToRefine
@@ -3001,7 +2938,7 @@ void Foam::snappyRefineDriver::splitAndMergeBaffles
     // Merge all baffles that are still remaining after duplicating points.
     List<labelPair> couples(localPointRegion::findDuplicateFacePairs(mesh));
 
-    label nCouples = returnReduce(couples.size(), sumOp<label>());
+    const label nCouples = returnReduce(couples.size(), sumOp<label>());
 
     Info<< "Detected unsplittable baffles : " << nCouples << endl;
 
diff --git a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappySnapDriver.C b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappySnapDriver.C
index 0dadc652a2..4c5d1c035c 100644
--- a/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappySnapDriver.C
+++ b/src/mesh/snappyHexMesh/snappyHexMeshDriver/snappySnapDriver.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -82,7 +82,7 @@ Foam::label Foam::snappySnapDriver::getCollocatedPoints
     );
     bool hasMerged = (nUnique < points.size());
 
-    if (!returnReduce(hasMerged, orOp<bool>()))
+    if (!returnReduceOr(hasMerged))
     {
         return 0;
     }
@@ -215,9 +215,8 @@ Foam::tmp<Foam::pointField> Foam::snappySnapDriver::smoothInternalDisplacement
 
     if (debug)
     {
-        reduce(nInterface, sumOp<label>());
-        Info<< "Found " << nInterface << " faces out of "
-            << mesh.globalData().nTotalFaces()
+        Info<< "Found " << returnReduce(nInterface, sumOp<label>())
+            << " faces out of " << mesh.globalData().nTotalFaces()
             << " inbetween refinement regions." << endl;
     }
 
@@ -275,8 +274,8 @@ Foam::tmp<Foam::pointField> Foam::snappySnapDriver::smoothInternalDisplacement
         }
     }
 
-    reduce(nAdapted, sumOp<label>());
-    Info<< "Smoothing " << nAdapted << " points inbetween refinement regions."
+    Info<< "Smoothing " << returnReduce(nAdapted, sumOp<label>())
+        << " points inbetween refinement regions."
         << endl;
 
     return tdisplacement;
@@ -796,15 +795,12 @@ void Foam::snappySnapDriver::freezeExposedPoints
         0u
     );
 
-    if (returnReduce(isFrozenPoint.count(), sumOp<label>()))
+    for (const label pointi : isFrozenPoint)
     {
-        for (const label pointi : isFrozenPoint)
+        const auto iter = outside.meshPointMap().find(pointi);
+        if (iter.found())
         {
-            const auto& iter = outside.meshPointMap().find(pointi);
-            if (iter.found())
-            {
-                outsideDisp[iter()] = Zero;
-            }
+            outsideDisp[iter.val()] = Zero;
         }
     }
 }
@@ -1835,7 +1831,7 @@ Foam::vectorField Foam::snappySnapDriver::calcNearestSurface
     // Displacement per patch point
     vectorField patchDisp(localPoints.size(), Zero);
 
-    if (returnReduce(localPoints.size(), sumOp<label>()) > 0)
+    if (returnReduceOr(localPoints.size()))
     {
         // Current surface snapped to. Used to check whether points have been
         // snapped at all
diff --git a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
index d03d360c4c..e5d0d68add 100644
--- a/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
+++ b/src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolation.C
@@ -206,9 +206,7 @@ void Foam::AMIInterpolation::normaliseWeights
 
     if (output)
     {
-        const label nFace = returnReduce(wght.size(), sumOp<label>());
-
-        if (nFace)
+        if (returnReduceOr(wght.size()))
         {
             Info<< indent
                 << "AMI: Patch " << patchName
diff --git a/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatchTopologyChange.C b/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatchTopologyChange.C
index a1c6634e28..ad098dd3ca 100644
--- a/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatchTopologyChange.C
+++ b/src/meshTools/AMIInterpolation/patches/cyclicAMI/cyclicAMIPolyPatch/cyclicAMIPolyPatchTopologyChange.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -254,7 +254,7 @@ bool Foam::cyclicAMIPolyPatch::addAMIFaces(polyTopoChange& topoChange)
             << " "  << nbr.name() << ": " << nNewTgtFaces << endl;
     }
 
-    return returnReduce(changedFaces, orOp<bool>());
+    return returnReduceOr(changedFaces);
 }
 
 
diff --git a/src/meshTools/AMIInterpolation/patches/cyclicPeriodicAMI/cyclicPeriodicAMIPolyPatch/cyclicPeriodicAMIPolyPatch.C b/src/meshTools/AMIInterpolation/patches/cyclicPeriodicAMI/cyclicPeriodicAMIPolyPatch/cyclicPeriodicAMIPolyPatch.C
index fb7e1af8fb..22bfe08812 100644
--- a/src/meshTools/AMIInterpolation/patches/cyclicPeriodicAMI/cyclicPeriodicAMIPolyPatch/cyclicPeriodicAMIPolyPatch.C
+++ b/src/meshTools/AMIInterpolation/patches/cyclicPeriodicAMI/cyclicPeriodicAMIPolyPatch/cyclicPeriodicAMIPolyPatch.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -86,7 +86,7 @@ void Foam::cyclicPeriodicAMIPolyPatch::syncTransforms() const
         );
 
         // If there are any zero-sized periodic patches
-        if (returnReduce((size() && !periodicPatch.size()), orOp<bool>()))
+        if (returnReduceOr(size() && !periodicPatch.size()))
         {
             if (periodicPatch.separation().size() > 1)
             {
@@ -119,14 +119,14 @@ void Foam::cyclicPeriodicAMIPolyPatch::syncTransforms() const
 
             // Note that a cyclic with zero faces is considered parallel so
             // explicitly check for that.
-            bool isParallel =
-            (
-                periodicPatch.size()
-             && periodicPatch.parallel()
-            );
-            reduce(isParallel, orOp<bool>());
 
-            if (isParallel)
+            if
+            (
+                returnReduceOr
+                (
+                    periodicPatch.size() && periodicPatch.parallel()
+                )
+            )
             {
                 // Sync a list of separation vectors
                 List<vectorField> sep(Pstream::nProcs());
@@ -501,9 +501,7 @@ void Foam::cyclicPeriodicAMIPolyPatch::resetAMI() const
         }
 
         // Print some statistics
-        const label nFace = returnReduce(size(), sumOp<label>());
-
-        if (nFace)
+        if (returnReduceOr(size()))
         {
             scalarField srcWghtSum(size(), Zero);
             forAll(srcWghtSum, faceI)
diff --git a/src/meshTools/algorithms/MeshWave/FaceCellWave.C b/src/meshTools/algorithms/MeshWave/FaceCellWave.C
index 89c15a2fa4..04a7865b80 100644
--- a/src/meshTools/algorithms/MeshWave/FaceCellWave.C
+++ b/src/meshTools/algorithms/MeshWave/FaceCellWave.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -900,7 +900,7 @@ Foam::FaceCellWave<Type, TrackingData>::FaceCellWave
     hasCyclicPatches_(hasPatch<cyclicPolyPatch>()),
     hasCyclicAMIPatches_
     (
-        returnReduce(hasPatch<cyclicAMIPolyPatch>(), orOp<bool>())
+        returnReduceOr(hasPatch<cyclicAMIPolyPatch>())
     ),
     nEvals_(0),
     nUnvisitedCells_(mesh_.nCells()),
@@ -948,7 +948,7 @@ Foam::FaceCellWave<Type, TrackingData>::FaceCellWave
     hasCyclicPatches_(hasPatch<cyclicPolyPatch>()),
     hasCyclicAMIPatches_
     (
-        returnReduce(hasPatch<cyclicAMIPolyPatch>(), orOp<bool>())
+        returnReduceOr(hasPatch<cyclicAMIPolyPatch>())
     ),
     nEvals_(0),
     nUnvisitedCells_(mesh_.nCells()),
@@ -1015,7 +1015,7 @@ Foam::FaceCellWave<Type, TrackingData>::FaceCellWave
     hasCyclicAMIPatches_
     (
         handleCyclicAMI
-     && returnReduce(hasPatch<cyclicAMIPolyPatch>(), orOp<bool>())
+     && returnReduceOr(hasPatch<cyclicAMIPolyPatch>())
     ),
     nEvals_(0),
     nUnvisitedCells_(mesh_.nCells()),
diff --git a/src/meshTools/algorithms/PointEdgeWave/PointEdgeWave.C b/src/meshTools/algorithms/PointEdgeWave/PointEdgeWave.C
index 5791929cce..c2f6bd7220 100644
--- a/src/meshTools/algorithms/PointEdgeWave/PointEdgeWave.C
+++ b/src/meshTools/algorithms/PointEdgeWave/PointEdgeWave.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -595,12 +595,8 @@ Foam::label Foam::PointEdgeWave<Type, TrackingData>::handleCollocatedPoints()
         }
     }
 
-    // Sum nChangedPoints over all procs
-    label totNChanged = nChangedPoints_;
-
-    reduce(totNChanged, sumOp<label>());
-
-    return totNChanged;
+    // Sum changedPoints over all procs
+    return returnReduce(nChangedPoints_, sumOp<label>());
 }
 
 
@@ -827,12 +823,8 @@ Foam::label Foam::PointEdgeWave<Type, TrackingData>::edgeToPoint()
     //    Pout<< "Changed points            : " << nChangedPoints_ << endl;
     //}
 
-    // Sum nChangedPoints over all procs
-    label totNChanged = nChangedPoints_;
-
-    reduce(totNChanged, sumOp<label>());
-
-    return totNChanged;
+    // Sum changedPoints over all procs
+    return returnReduce(nChangedPoints_, sumOp<label>());
 }
 
 
@@ -895,12 +887,8 @@ Foam::label Foam::PointEdgeWave<Type, TrackingData>::pointToEdge()
     //    Pout<< "Changed edges             : " << nChangedEdges_ << endl;
     //}
 
-    // Sum nChangedPoints over all procs
-    label totNChanged = nChangedEdges_;
-
-    reduce(totNChanged, sumOp<label>());
-
-    return totNChanged;
+    // Sum changedEdges over all procs
+    return returnReduce(nChangedEdges_, sumOp<label>());
 }
 
 
diff --git a/src/meshTools/cellClassification/cellClassification.C b/src/meshTools/cellClassification/cellClassification.C
index 58f9cce9ac..bf0a7d6580 100644
--- a/src/meshTools/cellClassification/cellClassification.C
+++ b/src/meshTools/cellClassification/cellClassification.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -288,12 +288,12 @@ void Foam::cellClassification::markCells
         // Use linear search for points.
         label celli = queryMesh.findCell(outsidePts[outsidePtI], -1, false);
 
-        if (returnReduce(celli, maxOp<label>()) == -1)
+        if (returnReduceAnd(celli < 0))
         {
             FatalErrorInFunction
                 << "outsidePoint " << outsidePts[outsidePtI]
-                << " is not inside any cell"
-                << nl << "It might be on a face or outside the geometry"
+                << " is not inside any cell" << nl
+                << "It might be on a face or outside the geometry"
                 << exit(FatalError);
         }
 
diff --git a/src/meshTools/meshStructure/meshStructure.C b/src/meshTools/meshStructure/meshStructure.C
index cba8524a66..b3db56c4d5 100644
--- a/src/meshTools/meshStructure/meshStructure.C
+++ b/src/meshTools/meshStructure/meshStructure.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -390,7 +390,7 @@ void Foam::meshStructure::correct
             }
         }
 
-        reduce(structured_, andOp<bool>());
+        Pstream::reduceAnd(structured_);
     }
 }
 
diff --git a/src/meshTools/output/vtk/patch/foamVtkPatchMeshWriter.C b/src/meshTools/output/vtk/patch/foamVtkPatchMeshWriter.C
index 2194acb2df..f12762e7d4 100644
--- a/src/meshTools/output/vtk/patch/foamVtkPatchMeshWriter.C
+++ b/src/meshTools/output/vtk/patch/foamVtkPatchMeshWriter.C
@@ -688,7 +688,7 @@ bool Foam::vtk::patchMeshWriter::writeNeighIDs()
     this->endDataArray();
 
     // MPI barrier
-    return parallel_ ? returnReduce(good, orOp<bool>()) : good;
+    return parallel_ ? returnReduceOr(good) : good;
 }
 
 
diff --git a/src/meshTools/polyTopoChange/polyTopoChange.C b/src/meshTools/polyTopoChange/polyTopoChange.C
index 58dca2b07c..aea78d1fef 100644
--- a/src/meshTools/polyTopoChange/polyTopoChange.C
+++ b/src/meshTools/polyTopoChange/polyTopoChange.C
@@ -2001,12 +2001,7 @@ void Foam::polyTopoChange::reorderCoupledFaces
         }
     }
 
-    if (syncParallel)
-    {
-        reduce(anyChanged, orOp<bool>());
-    }
-
-    if (anyChanged)
+    if (syncParallel ? returnReduceOr(anyChanged) : anyChanged)
     {
         // Reorder faces according to oldToNew.
         reorderCompactFaces(oldToNew.size(), oldToNew);
diff --git a/src/meshTools/primitiveMeshGeometry/primitiveMeshGeometry.C b/src/meshTools/primitiveMeshGeometry/primitiveMeshGeometry.C
index 75ac9dc72b..cb6d5bd663 100644
--- a/src/meshTools/primitiveMeshGeometry/primitiveMeshGeometry.C
+++ b/src/meshTools/primitiveMeshGeometry/primitiveMeshGeometry.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -341,8 +341,7 @@ bool Foam::primitiveMeshGeometry::checkFaceDotProduct
     reduce(severeNonOrth, sumOp<label>());
     reduce(errorNonOrth, sumOp<label>());
 
-    label neiSize = nei.size();
-    reduce(neiSize, sumOp<label>());
+    const label neiSize = returnReduce(nei.size(), sumOp<label>());
 
     // Only report if there are some internal faces
     if (neiSize > 0)
diff --git a/src/meshTools/processorLOD/box/box.C b/src/meshTools/processorLOD/box/box.C
index 78e96a80d3..c6c867f350 100644
--- a/src/meshTools/processorLOD/box/box.C
+++ b/src/meshTools/processorLOD/box/box.C
@@ -413,7 +413,7 @@ bool Foam::processorLODs::box::doRefineBoxes
         newToOld_[proci].transfer(newProcNewToOld);
     }
 
-    return returnReduce(refineBoxes, orOp<bool>());
+    return returnReduceOr(refineBoxes);
 }
 
 
diff --git a/src/meshTools/regionSplit/localPointRegion.C b/src/meshTools/regionSplit/localPointRegion.C
index 5a326c2ae9..7d6c0fb292 100644
--- a/src/meshTools/regionSplit/localPointRegion.C
+++ b/src/meshTools/regionSplit/localPointRegion.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -410,7 +410,7 @@ void Foam::localPointRegion::calcPointRegions
 
         //Pout<< "nChanged:" << nChanged << endl;
 
-        if (returnReduce(nChanged, sumOp<label>()) == 0)
+        if (!returnReduceOr(nChanged))
         {
             break;
         }
diff --git a/src/meshTools/regionSplit/regionSplit.C b/src/meshTools/regionSplit/regionSplit.C
index 532b7ba361..8f31dd33f2 100644
--- a/src/meshTools/regionSplit/regionSplit.C
+++ b/src/meshTools/regionSplit/regionSplit.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2013 OpenFOAM Foundation
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -679,7 +679,7 @@ Foam::regionSplit::reduceRegionsImpl
         emitWarning = false;
         // Continue until there are no further changes
     }
-    while (returnReduce(!updateLookup.empty(), orOp<bool>()));
+    while (returnReduceOr(updateLookup.size()));
 
 
     //
diff --git a/src/meshTools/regionSplit2D/regionSplit2D.C b/src/meshTools/regionSplit2D/regionSplit2D.C
index dc22cde350..6d7271e401 100644
--- a/src/meshTools/regionSplit2D/regionSplit2D.C
+++ b/src/meshTools/regionSplit2D/regionSplit2D.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -91,7 +91,7 @@ Foam::regionSplit2D::regionSplit2D
     }
 
     // Early exit if there are no blocked faces
-    if (returnReduce(nBlockedFaces, sumOp<label>()) == 0)
+    if (!returnReduceOr(nBlockedFaces))
     {
         return;
     }
diff --git a/src/meshTools/searchableSurfaces/searchableSurfaceWithGaps/searchableSurfaceWithGaps.C b/src/meshTools/searchableSurfaces/searchableSurfaceWithGaps/searchableSurfaceWithGaps.C
index 1a504697e4..7230ce8f37 100644
--- a/src/meshTools/searchableSurfaces/searchableSurfaceWithGaps/searchableSurfaceWithGaps.C
+++ b/src/meshTools/searchableSurfaces/searchableSurfaceWithGaps/searchableSurfaceWithGaps.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -217,7 +218,7 @@ void Foam::searchableSurfaceWithGaps::findLine
     labelList compactMap;
     label nMiss = countMisses(info, compactMap);
 
-    if (returnReduce(nMiss, sumOp<label>()) > 0)
+    if (returnReduceOr(nMiss))
     {
         //Pout<< "** retesting with offset0 " << nMiss << " misses out of "
         //    << start.size() << endl;
@@ -272,7 +273,7 @@ void Foam::searchableSurfaceWithGaps::findLine
         labelList plusMissMap;
         nMiss = countMisses(plusInfo, minInfo, plusMissMap);
 
-        if (returnReduce(nMiss, sumOp<label>()) > 0)
+        if (returnReduceOr(nMiss))
         {
             //Pout<< "** retesting with offset1 " << nMiss << " misses out of "
             //    << start.size() << endl;
diff --git a/src/meshTools/searchableSurfaces/searchableSurfaces/searchableSurfaces.C b/src/meshTools/searchableSurfaces/searchableSurfaces/searchableSurfaces.C
index d94345b69c..340c2a6aa3 100644
--- a/src/meshTools/searchableSurfaces/searchableSurfaces/searchableSurfaces.C
+++ b/src/meshTools/searchableSurfaces/searchableSurfaces/searchableSurfaces.C
@@ -510,7 +510,7 @@ bool Foam::searchableSurfaces::checkClosed(const bool report) const
         Info<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
@@ -556,7 +556,7 @@ bool Foam::searchableSurfaces::checkNormalOrientation(const bool report) const
         Info<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
@@ -604,7 +604,7 @@ bool Foam::searchableSurfaces::checkSizes
         Info<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
@@ -744,7 +744,7 @@ bool Foam::searchableSurfaces::checkIntersection
         Info<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 }
 
 
@@ -807,7 +807,7 @@ bool Foam::searchableSurfaces::checkQuality
         Info<< endl;
     }
 
-    return returnReduce(hasError, orOp<bool>());
+    return returnReduceOr(hasError);
 
 }
 
diff --git a/src/meshTools/topoSet/cellSources/haloToCell/haloToCell.C b/src/meshTools/topoSet/cellSources/haloToCell/haloToCell.C
index 60c2dc436a..83a9a6d8bf 100644
--- a/src/meshTools/topoSet/cellSources/haloToCell/haloToCell.C
+++ b/src/meshTools/topoSet/cellSources/haloToCell/haloToCell.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -167,7 +167,7 @@ void Foam::haloToCell::combine(topoSet& set, const bool add) const
         }
 
         // Could have early exit, but needs to be parallel-synchronized
-        // if (returnReduce(updates.none(), andOp<bool>()))
+        // if (returnReduceAnd(updates.none()))
         // {
         //     break;
         // }
diff --git a/src/meshTools/topoSet/cellSources/surfaceToCell/surfaceToCell.C b/src/meshTools/topoSet/cellSources/surfaceToCell/surfaceToCell.C
index 37611e55f4..237444e5e3 100644
--- a/src/meshTools/topoSet/cellSources/surfaceToCell/surfaceToCell.C
+++ b/src/meshTools/topoSet/cellSources/surfaceToCell/surfaceToCell.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2020 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -188,11 +188,12 @@ void Foam::surfaceToCell::combine(topoSet& set, const bool add) const
         {
             // Find cell point is in. Linear search.
             label celli = queryMesh.findCell(outsidePoint, -1, false);
-            if (returnReduce(celli, maxOp<label>()) == -1)
+
+            if (returnReduceAnd(celli < 0))
             {
                 FatalErrorInFunction
                     << "outsidePoint " << outsidePoint
-                    << " is not inside any cell"
+                    << " is not inside any cell" << nl
                     << exit(FatalError);
             }
         }
diff --git a/src/meshTools/topoSet/faceSources/holeToFace/holeToFace.C b/src/meshTools/topoSet/faceSources/holeToFace/holeToFace.C
index 9635ac2526..cdeb753361 100644
--- a/src/meshTools/topoSet/faceSources/holeToFace/holeToFace.C
+++ b/src/meshTools/topoSet/faceSources/holeToFace/holeToFace.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020-2021 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -712,9 +712,8 @@ Foam::bitSet Foam::holeToFace::findClosure
     //        }
     //    }
     //}
-    //reduce(haveLeak, orOp<bool>());
     //
-    //if (!haveLeak)
+    //if (!returnReduceOr(haveLeak))
     //{
     //    if (debug)
     //    {
@@ -1237,7 +1236,7 @@ Foam::autoPtr<Foam::mapDistribute> Foam::holeToFace::calcClosure
     }
 
 
-    if (returnReduce(closureFaces.size(), sumOp<label>()) == 0)
+    if (returnReduceAnd(closureFaces.empty()))
     {
         closureToBlocked.clear();
         return nullptr;
diff --git a/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/faceCells/faceCells.C b/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/faceCells/faceCells.C
index e2b6ec05f4..9f1d346ed7 100644
--- a/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/faceCells/faceCells.C
+++ b/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/faceCells/faceCells.C
@@ -7,7 +7,7 @@
 -------------------------------------------------------------------------------
     Copyright (C) 2007-2019 PCOpt/NTUA
     Copyright (C) 2013-2019 FOSS GP
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -72,9 +72,10 @@ faceCells::faceCells
             zeroATCcells_.append(zoneCells);
         }
     }
-    label size = zeroATCcells_.size();
-    reduce(size, sumOp<label>());
-    Info<< "Setting limiter on " << size << " cells" << nl << endl;
+
+    Info<< "Setting limiter on "
+        << returnReduce(zeroATCcells_.size(), sumOp<label>())
+        << " cells" << nl << endl;
 }
 
 
diff --git a/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/pointCells/pointCells.C b/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/pointCells/pointCells.C
index b46ae6c328..182ea00342 100644
--- a/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/pointCells/pointCells.C
+++ b/src/optimisation/adjointOptimisation/adjoint/ATCModel/zeroATCcells/pointCells/pointCells.C
@@ -7,7 +7,7 @@
 -------------------------------------------------------------------------------
     Copyright (C) 2007-2019 PCOpt/NTUA
     Copyright (C) 2013-2019 FOSS GP
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -96,12 +96,12 @@ pointCells::pointCells
             }
         }
     }
-    zeroedIDs.setSize(i);
-    zeroATCcells_ = zeroedIDs;
+    zeroedIDs.resize(i);
+    zeroATCcells_ = std::move(zeroedIDs);
 
-    label size = zeroATCcells_.size();
-    reduce(size, sumOp<label>());
-    Info<< "Zeroing ATC on "<< size << " cells" << nl << endl;
+    Info<< "Zeroing ATC on "
+        << returnReduce(zeroATCcells_.size(), sumOp<label>())
+        << " cells" << nl << endl;
 }
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/optimisation/adjointOptimisation/adjoint/optimisation/adjointSensitivity/incompressible/sensitivitySurfacePoints/sensitivitySurfacePointsIncompressible.C b/src/optimisation/adjointOptimisation/adjoint/optimisation/adjointSensitivity/incompressible/sensitivitySurfacePoints/sensitivitySurfacePointsIncompressible.C
index 2d0da2b7f7..74e6455ea3 100644
--- a/src/optimisation/adjointOptimisation/adjoint/optimisation/adjointSensitivity/incompressible/sensitivitySurfacePoints/sensitivitySurfacePointsIncompressible.C
+++ b/src/optimisation/adjointOptimisation/adjoint/optimisation/adjointSensitivity/incompressible/sensitivitySurfacePoints/sensitivitySurfacePointsIncompressible.C
@@ -372,9 +372,9 @@ sensitivitySurfacePoints::sensitivitySurfacePoints
     label nTotalPoints(0);
     for (const label patchI : sensitivityPatchIDs_)
     {
-        label nPoints = mesh_.boundaryMesh()[patchI].nPoints();
-        nTotalPoints += returnReduce(nPoints, sumOp<label>());
+        nTotalPoints += mesh_.boundaryMesh()[patchI].nPoints();
     }
+    reduce(nTotalPoints, sumOp<label>());
 
     // Derivatives for all (x,y,z) components of the displacement are kept
     derivatives_ = scalarField(3*nTotalPoints, Zero);
diff --git a/src/optimisation/adjointOptimisation/adjoint/parameterization/NURBS/NURBS3DSurface/NURBS3DSurface.C b/src/optimisation/adjointOptimisation/adjoint/parameterization/NURBS/NURBS3DSurface/NURBS3DSurface.C
index 855fd3fd0a..9b6554fa90 100644
--- a/src/optimisation/adjointOptimisation/adjoint/parameterization/NURBS/NURBS3DSurface/NURBS3DSurface.C
+++ b/src/optimisation/adjointOptimisation/adjoint/parameterization/NURBS/NURBS3DSurface/NURBS3DSurface.C
@@ -7,7 +7,7 @@
 -------------------------------------------------------------------------------
     Copyright (C) 2007-2019 PCOpt/NTUA
     Copyright (C) 2013-2019 FOSS GP
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -1190,15 +1190,13 @@ tmp<vector2DField> NURBS3DSurface::findClosestSurfacePoint
         paramCoors[pI].x() = u;
         paramCoors[pI].y() = v;
     }
-    reduce(nBoundedPoints, sumOp<label>());
-    reduce(maxResidual, maxOp<scalar>());
-    reduce(maxResidualDeriv, maxOp<scalar>());
+
     Info<< "Points that couldn't reach the residual limit::             "
-        << nBoundedPoints   << endl
+        << returnReduce(nBoundedPoints, sumOp<label>()) << nl
         << "Max residual after reaching iterations limit::              "
-        << maxResidual      << endl
+        << returnReduce(maxResidual, maxOp<scalar>()) << nl
         << "Max residual derivative after reaching iterations limit::   "
-        << maxResidualDeriv << endl
+        << returnReduce(maxResidualDeriv, maxOp<scalar>()) << nl
         << endl;
 
     return tparamCoors;
diff --git a/src/overset/cellCellStencil/cellVolumeWeight/cellVolumeWeightCellCellStencil.C b/src/overset/cellCellStencil/cellVolumeWeight/cellVolumeWeightCellCellStencil.C
index f57895b958..3f409f1fea 100644
--- a/src/overset/cellCellStencil/cellVolumeWeight/cellVolumeWeightCellCellStencil.C
+++ b/src/overset/cellCellStencil/cellVolumeWeight/cellVolumeWeightCellCellStencil.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2014-2020 OpenCFD Ltd.
+    Copyright (C) 2014-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -137,7 +137,7 @@ void Foam::cellCellStencils::cellVolumeWeight::walkFront
     // Current interpolation fraction
     scalar fraction = 1.0;
 
-    while (fraction > SMALL && returnReduce(isFront.count(), sumOp<label>()))
+    while (fraction > SMALL && returnReduceOr(isFront.any()))
     {
         // Interpolate cells on front
 
@@ -420,8 +420,7 @@ void Foam::cellCellStencils::cellVolumeWeight::findHoles
         }
 
 
-        reduce(nChanged, sumOp<label>());
-        if (nChanged == 0)
+        if (!returnReduceOr(nChanged))
         {
             break;
         }
diff --git a/src/overset/cellCellStencil/inverseDistance/inverseDistanceCellCellStencil.C b/src/overset/cellCellStencil/inverseDistance/inverseDistanceCellCellStencil.C
index ee52182aac..63e2fae6be 100644
--- a/src/overset/cellCellStencil/inverseDistance/inverseDistanceCellCellStencil.C
+++ b/src/overset/cellCellStencil/inverseDistance/inverseDistanceCellCellStencil.C
@@ -1306,7 +1306,7 @@ void Foam::cellCellStencils::inverseDistance::walkFront
     }
 
 
-    while (returnReduce(isFront.any(), orOp<bool>()))
+    while (returnReduceOr(isFront.any()))
     {
         // Interpolate cells on front
         bitSet newIsFront(mesh_.nFaces());
@@ -1502,7 +1502,7 @@ void Foam::cellCellStencils::inverseDistance::createStencil
         }
 
 
-        if (returnReduce(nSamples, sumOp<label>()) == 0)
+        if (!returnReduceOr(nSamples))
         {
             break;
         }
@@ -2293,18 +2293,15 @@ bool Foam::cellCellStencils::inverseDistance::update()
                 nLocal++;
             }
         }
-        reduce(nLocal, sumOp<label>());
-        reduce(nMixed, sumOp<label>());
-        reduce(nRemote, sumOp<label>());
 
         Info<< "Overset analysis : nCells : "
             << returnReduce(cellTypes_.size(), sumOp<label>()) << nl
             << incrIndent
             << indent << "calculated   : " << nCells[CALCULATED] << nl
             << indent << "interpolated : " << nCells[INTERPOLATED]
-            << " (interpolated from local:" << nLocal
-            << "  mixed local/remote:" << nMixed
-            << "  remote:" << nRemote << ")" << nl
+            << " (from local:" << returnReduce(nLocal, sumOp<label>())
+            << "  mixed local/remote:" << returnReduce(nMixed, sumOp<label>())
+            << "  remote:" << returnReduce(nRemote, sumOp<label>()) << ")" << nl
             << indent << "hole         : " << nCells[HOLE] << nl
             << decrIndent << endl;
     }
diff --git a/src/overset/cellCellStencil/inverseDistance/waveMethod.C b/src/overset/cellCellStencil/inverseDistance/waveMethod.C
index e3dd8a9c55..23e42308fe 100644
--- a/src/overset/cellCellStencil/inverseDistance/waveMethod.C
+++ b/src/overset/cellCellStencil/inverseDistance/waveMethod.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -117,7 +117,7 @@ void Foam::waveMethod::calculate
                 }
             }
 
-            if (returnReduce(changedFaces.empty(), andOp<bool>()))
+            if (returnReduceAnd(changedFaces.empty()))
             {
                 break;
             }
diff --git a/src/overset/cellCellStencil/trackingInverseDistance/trackingInverseDistanceCellCellStencil.C b/src/overset/cellCellStencil/trackingInverseDistance/trackingInverseDistanceCellCellStencil.C
index 9b91a0f5bf..40866cab61 100644
--- a/src/overset/cellCellStencil/trackingInverseDistance/trackingInverseDistanceCellCellStencil.C
+++ b/src/overset/cellCellStencil/trackingInverseDistance/trackingInverseDistanceCellCellStencil.C
@@ -688,7 +688,7 @@ bool Foam::cellCellStencils::trackingInverseDistance::update()
                 allPatchTypes
             );
 
-            //if (returnReduce(ok, andOp<bool>()))
+            //if (returnReduceAnd(ok))
             if (ok)
             {
                 break;
@@ -1115,18 +1115,15 @@ bool Foam::cellCellStencils::trackingInverseDistance::update()
                 nLocal++;
             }
         }
-        reduce(nLocal, sumOp<label>());
-        reduce(nMixed, sumOp<label>());
-        reduce(nRemote, sumOp<label>());
 
         Info<< "Overset analysis : nCells : "
             << returnReduce(cellTypes_.size(), sumOp<label>()) << nl
             << incrIndent
             << indent << "calculated   : " << nCells[CALCULATED] << nl
             << indent << "interpolated : " << nCells[INTERPOLATED]
-            << " (interpolated from local:" << nLocal
-            << "  mixed local/remote:" << nMixed
-            << "  remote:" << nRemote << ")" << nl
+            << " (from local:" << returnReduce(nLocal, sumOp<label>())
+            << "  mixed local/remote:" << returnReduce(nMixed, sumOp<label>())
+            << "  remote:" << returnReduce(nRemote, sumOp<label>()) << ")" << nl
             << indent << "hole         : " << nCells[HOLE] << nl
             << decrIndent << endl;
     }
diff --git a/src/overset/dynamicOversetFvMesh/dynamicOversetFvMesh.C b/src/overset/dynamicOversetFvMesh/dynamicOversetFvMesh.C
index fbe53ba44e..e8022b5094 100644
--- a/src/overset/dynamicOversetFvMesh/dynamicOversetFvMesh.C
+++ b/src/overset/dynamicOversetFvMesh/dynamicOversetFvMesh.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2014-2021 OpenCFD Ltd.
+    Copyright (C) 2014-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -473,7 +473,6 @@ void Foam::dynamicOversetFvMesh::writeAgglomeration
         label coarseSize = max(addr)+1;
 
         Info<< "Level : " << level << endl
-            << returnReduce(addr.size(), sumOp<label>()) << endl
             << "    current size      : "
             << returnReduce(addr.size(), sumOp<label>()) << endl
             << "    agglomerated size : "
diff --git a/src/overset/dynamicOversetFvMesh/dynamicOversetFvMeshTemplates.C b/src/overset/dynamicOversetFvMesh/dynamicOversetFvMeshTemplates.C
index 7466878bb7..37c49bb5be 100644
--- a/src/overset/dynamicOversetFvMesh/dynamicOversetFvMeshTemplates.C
+++ b/src/overset/dynamicOversetFvMesh/dynamicOversetFvMeshTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2014-2019 OpenCFD Ltd.
+    Copyright (C) 2014-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -189,15 +189,13 @@ Foam::tmp<Foam::scalarField> Foam::dynamicOversetFvMesh::normalisation
         }
     }
 
-    reduce(nZeroDiag, sumOp<label>());
-
     if (debug)
     {
         Pout<< "For field " << m.psi().name() << " have zero diagonals for "
-            << nZeroDiag << " cells" << endl;
+            << returnReduce(nZeroDiag, sumOp<label>()) << " cells" << endl;
     }
 
-    if (nZeroDiag > 0)
+    if (returnReduceOr(nZeroDiag))
     {
         // Walk out the norm across hole cells
 
@@ -293,8 +291,7 @@ Foam::tmp<Foam::scalarField> Foam::dynamicOversetFvMesh::normalisation
                 }
             }
 
-            reduce(nChanged, sumOp<label>());
-            if (nChanged == 0)
+            if (!returnReduceOr(nChanged))
             {
                 break;
             }
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
index e5bb9b0030..cf1f6daeed 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2016 OpenFOAM Foundation
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -231,9 +231,8 @@ void Foam::decompositionConstraints::preserveBaffles::apply
 
     if (decompositionConstraint::debug & 2)
     {
-        reduce(nChanged, sumOp<label>());
-        Info<< type() << " : changed decomposition on " << nChanged
-            << " cells" << endl;
+        Info<< type() << " : changed decomposition on "
+            << returnReduce(nChanged, sumOp<label>()) << " cells" << endl;
     }
 }
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
index 5952e305a2..4e825fe757 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2016 OpenFOAM Foundation
-    Copyright (C) 2018,2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -119,8 +119,8 @@ void Foam::decompositionConstraints::preserveFaceZones::add
 
     if (decompositionConstraint::debug & 2)
     {
-        reduce(nUnblocked, sumOp<label>());
-        Info<< type() << " : unblocked " << nUnblocked << " faces" << endl;
+        Info<< type() << " : unblocked "
+            << returnReduce(nUnblocked, sumOp<label>()) << " faces" << endl;
     }
 
     syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
@@ -140,7 +140,7 @@ void Foam::decompositionConstraints::preserveFaceZones::apply
     // If the decomposition has not enforced the constraint do it over
     // here.
 
-    label nChanged;
+    label nChanged = 0;
 
     do
     {
@@ -188,16 +188,13 @@ void Foam::decompositionConstraints::preserveFaceZones::apply
             }
         }
 
-        reduce(nChanged, sumOp<label>());
-
         if (decompositionConstraint::debug & 2)
         {
-            reduce(nChanged, sumOp<label>());
-            Info<< type() << " : changed decomposition on " << nChanged
-                << " cells" << endl;
+            Info<< type() << " : changed decomposition on "
+                << returnReduce(nChanged, sumOp<label>()) << " cells" << endl;
         }
 
-    } while (nChanged > 0);
+    } while (returnReduceOr(nChanged));
 }
 
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
index 10f65341aa..6e24d35f94 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2016 OpenFOAM Foundation
-    Copyright (C) 2018,2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -125,8 +125,8 @@ void Foam::decompositionConstraints::preservePatches::add
 
     if (decompositionConstraint::debug & 2)
     {
-        reduce(nUnblocked, sumOp<label>());
-        Info<< type() << " : unblocked " << nUnblocked << " faces" << endl;
+        Info<< type() << " : unblocked "
+            << returnReduce(nUnblocked, sumOp<label>()) << " faces" << endl;
     }
 
     syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
@@ -152,7 +152,7 @@ void Foam::decompositionConstraints::preservePatches::apply
     // Synchronise decomposition on patchIDs
     // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-    label nChanged;
+    label nChanged = 0;
 
     do
     {
@@ -184,15 +184,13 @@ void Foam::decompositionConstraints::preservePatches::apply
             }
         }
 
-        reduce(nChanged, sumOp<label>());
-
         if (decompositionConstraint::debug & 2)
         {
-            Info<< type() << " : changed decomposition on " << nChanged
-                << " cells" << endl;
+            Info<< type() << " : changed decomposition on "
+                << returnReduce(nChanged, sumOp<label>()) << " cells" << endl;
         }
 
-    } while (nChanged > 0);
+    } while (returnReduceOr(nChanged));
 }
 
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.C
index 65c0470893..4a908abc5f 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2019,2022 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -201,9 +201,7 @@ void Foam::decompositionConstraints::singleProcessorFaceSets::add
             }
         }
 
-        reduce(store, orOp<bool>());
-
-        if (store)
+        if (returnReduceOr(store))
         {
             specifiedProcessorFaces.append(new labelList(fz.sortedToc()));
             specifiedProcessor.append(destProcI);
@@ -251,8 +249,8 @@ void Foam::decompositionConstraints::singleProcessorFaceSets::add
 
     if (decompositionConstraint::debug & 2)
     {
-        reduce(nUnblocked, sumOp<label>());
-        Info<< type() << " : unblocked " << nUnblocked << " faces" << endl;
+        Info<< type() << " : unblocked "
+            << returnReduce(nUnblocked, sumOp<label>()) << " faces" << endl;
     }
 
     syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
@@ -345,9 +343,8 @@ void Foam::decompositionConstraints::singleProcessorFaceSets::apply
 
     if (decompositionConstraint::debug & 2)
     {
-        reduce(nChanged, sumOp<label>());
-        Info<< type() << " : changed decomposition on " << nChanged
-            << " cells" << endl;
+        Info<< type() << " : changed decomposition on "
+            << returnReduce(nChanged, sumOp<label>()) << " cells" << endl;
     }
 }
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
index 28d7e1dc78..e1fcbdab12 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -869,7 +869,7 @@ Foam::labelList Foam::decompositionMethod::decompose
 ) const
 {
     // Any weights specified?
-    const bool hasWeights = returnReduce(!cellWeights.empty(), orOp<bool>());
+    const bool hasWeights = returnReduceOr(cellWeights.size());
 
     if (hasWeights && cellWeights.size() != mesh.nCells())
     {
@@ -881,10 +881,9 @@ Foam::labelList Foam::decompositionMethod::decompose
 
     // Any faces not blocked?
     const bool hasUnblocked =
-        returnReduce
+        returnReduceOr
         (
-            (!blockedFace.empty() && !BitOps::all(blockedFace)),
-            orOp<bool>()
+            !blockedFace.empty() && !BitOps::all(blockedFace)
         );
 
 
diff --git a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
index 7bfc8dd6c0..f62efd1659 100644
--- a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -182,7 +182,7 @@ bool Foam::hierarchGeomDecomp::findBinary
         // Safeguard if same as previous.
         bool hasNotChanged = (mag(midValue-midValuePrev) < SMALL);
 
-        if (returnReduce(hasNotChanged, andOp<bool>()))
+        if (returnReduceAnd(hasNotChanged))
         {
             if (debug)
             {
@@ -268,7 +268,7 @@ bool Foam::hierarchGeomDecomp::findBinary
         // Safeguard if same as previous.
         bool hasNotChanged = (mag(midValue-midValuePrev) < SMALL);
 
-        if (returnReduce(hasNotChanged, andOp<bool>()))
+        if (returnReduceAnd(hasNotChanged))
         {
             if (debug)
             {
diff --git a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
index 6642113b7b..08953fd02a 100644
--- a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
@@ -149,13 +149,7 @@ Foam::label Foam::metisLikeDecomp::decomposeGeneral
 
     // Ignore zero-sized weights ... and poorly sized ones too
     List<scalar> allWeights;
-    if
-    (
-        returnReduce
-        (
-            (cWeights.size() == globalCells.localSize()), andOp<bool>()
-        )
-    )
+    if (returnReduceAnd(cWeights.size() == globalCells.localSize()))
     {
         allWeights = globalCells.gather(cWeights);
     }
diff --git a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
index 1c663167cd..72edd426b7 100644
--- a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
@@ -359,7 +359,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
     const scalarField& weights
 ) const
 {
-    if (returnReduce((points.size() != weights.size()), orOp<bool>()))
+    if (returnReduceOr(points.size() != weights.size()))
     {
         // Ignore zero-sized weights ... and poorly sized ones too
         return decompose(points);
diff --git a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
index b494548e1b..2bf6e7d01c 100644
--- a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
+++ b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
@@ -221,7 +221,7 @@ Foam::label Foam::ptscotchDecomp::decompose
 
     // Check for externally provided cellweights and if so initialise weights
 
-    bool hasWeights = returnReduce(!cWeights.empty(), orOp<bool>());
+    bool hasWeights = returnReduceOr(cWeights.size());
 
     const scalar minWeights = hasWeights ? gMin(cWeights) : scalar(1);
 
diff --git a/src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C b/src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C
index fb2943864f..f9830ea560 100644
--- a/src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C
+++ b/src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C
@@ -3782,7 +3782,7 @@ void Foam::distributedTriSurfaceMesh::findLineAll
 
 
     label iter = 0;
-    while (returnReduce(e0.size(), sumOp<label>()) > 0)
+    while (returnReduceOr(e0.size()))
     {
         findLine
         (
@@ -4131,11 +4131,7 @@ void Foam::distributedTriSurfaceMesh::getVolumeType
         // status, all others will return UNKNOWN. Make INSIDE/OUTSIDE win.
         outsideVolType_ = volumeType
         (
-            returnReduce
-            (
-                label(outsideVolTypes[0]),
-                maxOp<label>()
-            )
+            returnReduce(int(outsideVolTypes[0]), maxOp<int>())
         );
 
         if (debug)
diff --git a/src/regionModels/regionModel/regionModel/regionModel.C b/src/regionModels/regionModel/regionModel/regionModel.C
index 80d78b96d7..be3b36b03c 100644
--- a/src/regionModels/regionModel/regionModel/regionModel.C
+++ b/src/regionModels/regionModel/regionModel/regionModel.C
@@ -114,7 +114,7 @@ void Foam::regionModels::regionModel::initialise()
     primaryPatchIDs_.transfer(primaryPatchIDs);
     intCoupledPatchIDs_.transfer(intCoupledPatchIDs);
 
-    if (returnReduce(nBoundaryFaces, sumOp<label>()) == 0)
+    if (!returnReduceOr(nBoundaryFaces))
     {
         WarningInFunction
             << "Region model has no mapped boundary conditions - transfer "
diff --git a/src/regionModels/thermalBaffleModels/thermalBaffleModel/thermalBaffleModel.C b/src/regionModels/thermalBaffleModels/thermalBaffleModel/thermalBaffleModel.C
index 77da201d24..c507d4cfe9 100644
--- a/src/regionModels/thermalBaffleModels/thermalBaffleModel/thermalBaffleModel.C
+++ b/src/regionModels/thermalBaffleModels/thermalBaffleModel/thermalBaffleModel.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -76,9 +76,7 @@ void thermalBaffleModel::init()
         nTotalEdges +=
             nLayers_*(rbm[patchi].nEdges() - rbm[patchi].nInternalEdges());
 
-        reduce(nTotalEdges, sumOp<label>());
-
-        label nFaces = 0;
+        label nTotalFaces = 0;
         forAll(rbm, patchi)
         {
             if (
@@ -90,19 +88,23 @@ void thermalBaffleModel::init()
                    )
                 )
             {
-                nFaces += rbm[patchi].size();
+                nTotalFaces += rbm[patchi].size();
             }
         }
-        reduce(nFaces, sumOp<label>());
 
-        if (nTotalEdges == nFaces)
+        oneD_ =
+        (
+            returnReduce(nTotalEdges, sumOp<label>())
+         == returnReduce(nTotalFaces, sumOp<label>())
+        );
+
+        if (oneD_)
         {
-            oneD_ = true;
-            Info << "\nThe thermal baffle is 1D \n" << endl;
+            Info << "\nThe thermal baffle is 1D\n" << endl;
         }
         else
         {
-            Info << "\nThe thermal baffle is 3D \n" << endl;
+            Info << "\nThe thermal baffle is 3D\n" << endl;
         }
 
         forAll(intCoupledPatchIDs_, i)
diff --git a/src/renumber/renumberMethods/structuredRenumber/OppositeFaceCellWave.C b/src/renumber/renumberMethods/structuredRenumber/OppositeFaceCellWave.C
index 90421ca140..4ab3daae5d 100644
--- a/src/renumber/renumberMethods/structuredRenumber/OppositeFaceCellWave.C
+++ b/src/renumber/renumberMethods/structuredRenumber/OppositeFaceCellWave.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -246,11 +247,7 @@ Foam::label Foam::OppositeFaceCellWave<Type, TrackingData>::faceToCell()
     }
 
     // Sum changedCells over all procs
-    label totNChanged = this->changedCells_.size();
-
-    reduce(totNChanged, sumOp<label>());
-
-    return totNChanged;
+    return returnReduce(this->changedCells_.size(), sumOp<label>());
 }
 
 
@@ -321,12 +318,8 @@ Foam::label Foam::OppositeFaceCellWave<Type, TrackingData>::cellToFace()
             << endl;
     }
 
-    // Sum nChangedFaces over all procs
-    label totNChanged = this->changedFaces_.size();
-
-    reduce(totNChanged, sumOp<label>());
-
-    return totNChanged;
+    // Sum changedFaces over all procs
+    return returnReduce(this->changedFaces_.size(), sumOp<label>());
 }
 
 
diff --git a/src/sampling/functions/Function1/Sample/SampleFunction1.C b/src/sampling/functions/Function1/Sample/SampleFunction1.C
index d71427e1fb..62f9dcff49 100644
--- a/src/sampling/functions/Function1/Sample/SampleFunction1.C
+++ b/src/sampling/functions/Function1/Sample/SampleFunction1.C
@@ -45,7 +45,7 @@ void Foam::Function1Types::Sample<Type>::setSampleCell() const
 
         celli_ = mesh.findCell(position_);
 
-        if (!returnReduce(celli_ != -1, orOp<bool>()))
+        if (returnReduceAnd(celli_ < 0))
         {
             FatalErrorInFunction
                 << "Sample cell could not be found at position "
diff --git a/src/sampling/meshToMesh/meshToMesh.C b/src/sampling/meshToMesh/meshToMesh.C
index 0383009453..6a15c093a4 100644
--- a/src/sampling/meshToMesh/meshToMesh.C
+++ b/src/sampling/meshToMesh/meshToMesh.C
@@ -381,9 +381,7 @@ void Foam::meshToMesh::normaliseWeights
     scalarListList& wght
 ) const
 {
-    const label nCell = returnReduce(wght.size(), sumOp<label>());
-
-    if (nCell > 0)
+    if (returnReduceOr(wght.size()))
     {
         forAll(wght, celli)
         {
diff --git a/src/sampling/meshToMesh/meshToMeshTemplates.C b/src/sampling/meshToMesh/meshToMeshTemplates.C
index 7fe01d548a..028801ca1b 100644
--- a/src/sampling/meshToMesh/meshToMeshTemplates.C
+++ b/src/sampling/meshToMesh/meshToMeshTemplates.C
@@ -140,7 +140,7 @@ void Foam::meshToMesh::mapSrcToTgt
 
     if (singleMeshProc_ == -1)
     {
-        if (returnReduce(tgtToSrcCellVec_.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(tgtToSrcCellVec_.empty()))
         {
             // No correction vectors calculated. Fall back to first order.
             mapSrcToTgt(srcField, cop, result);
@@ -353,7 +353,7 @@ void Foam::meshToMesh::mapTgtToSrc
 
     if (singleMeshProc_ == -1)
     {
-        if (returnReduce(srcToTgtCellVec_.size(), sumOp<label>()) == 0)
+        if (returnReduceAnd(srcToTgtCellVec_.empty()))
         {
             // No correction vectors calculated. Fall back to first order.
             mapTgtToSrc(tgtField, cop, result);
@@ -478,7 +478,7 @@ void Foam::meshToMesh::mapInternalSrcToTgt
     const bool secondOrder
 ) const
 {
-    if (secondOrder && returnReduce(tgtToSrcCellVec_.size(), sumOp<label>()))
+    if (secondOrder && returnReduceOr(tgtToSrcCellVec_.size()))
     {
         mapSrcToTgt
         (
@@ -711,7 +711,7 @@ void Foam::meshToMesh::mapInternalTgtToSrc
     const bool secondOrder
 ) const
 {
-    if (secondOrder && returnReduce(srcToTgtCellVec_.size(), sumOp<label>()))
+    if (secondOrder && returnReduceOr(srcToTgtCellVec_.size()))
     {
         mapTgtToSrc
         (
diff --git a/src/sampling/sampledSet/shortestPath/shortestPathSet.C b/src/sampling/sampledSet/shortestPath/shortestPathSet.C
index 12fb3059ef..e2dc40dd1c 100644
--- a/src/sampling/sampledSet/shortestPath/shortestPathSet.C
+++ b/src/sampling/sampledSet/shortestPath/shortestPathSet.C
@@ -497,8 +497,8 @@ bool Foam::shortestPathSet::genSingleLeakPath
                 << " Skipped route detection." << endl;
         }
     }
-    reduce(targetFound, orOp<bool>());
-    if (!targetFound)
+
+    if (!returnReduceOr(targetFound))
     {
         //Pout<< "now :"
         //    << " nLeakCell:"
@@ -638,7 +638,7 @@ bool Foam::shortestPathSet::genSingleLeakPath
 
         // Situation 1: we found the destination cell (do nothing),
         // frontCellI is -1 on all processors
-        if (returnReduce(frontCellI == -1, andOp<bool>()))
+        if (returnReduceAnd(frontCellI == -1))
         {
             //Pout<< "now :"
             //    << " nLeakCell:"
diff --git a/src/sampling/sampledSurface/sampledSurfaces/sampledSurfaces.C b/src/sampling/sampledSurface/sampledSurfaces/sampledSurfaces.C
index d187fb3b76..6cdedf80be 100644
--- a/src/sampling/sampledSurface/sampledSurfaces/sampledSurfaces.C
+++ b/src/sampling/sampledSurface/sampledSurfaces/sampledSurfaces.C
@@ -562,10 +562,9 @@ bool Foam::sampledSurfaces::performAction(unsigned request)
 
                 if
                 (
-                    returnReduce
+                    returnReduceAnd
                     (
-                        !ListOps::found(ids, lessOp1<label>(0)),
-                        andOp<bool>()
+                        !ListOps::found(ids, lessOp1<label>(0))
                     )
                 )
                 {
diff --git a/src/sampling/surface/cutting/cuttingSurfaceBaseSelection.C b/src/sampling/surface/cutting/cuttingSurfaceBaseSelection.C
index 216aa960ee..819f55cf2d 100644
--- a/src/sampling/surface/cutting/cuttingSurfaceBaseSelection.C
+++ b/src/sampling/surface/cutting/cuttingSurfaceBaseSelection.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2019 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -61,11 +61,7 @@ Foam::bitSet Foam::cuttingSurfaceBase::cellSelection
 
     // Zones requested and in use?
     const bool hasZones =
-        returnReduce
-        (
-            (-1 != mesh.cellZones().findIndex(zoneNames)),
-            andOp<bool>()
-        );
+        returnReduceAnd(-1 != mesh.cellZones().findIndex(zoneNames));
 
     if (hasZones)
     {
diff --git a/src/sampling/surface/distanceSurface/distanceSurfaceFilter.C b/src/sampling/surface/distanceSurface/distanceSurfaceFilter.C
index 566a7639c1..58d3892748 100644
--- a/src/sampling/surface/distanceSurface/distanceSurfaceFilter.C
+++ b/src/sampling/surface/distanceSurface/distanceSurfaceFilter.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020-2021 OpenCFD Ltd.
+    Copyright (C) 2020-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -431,7 +431,7 @@ void Foam::distanceSurface::filterRegionProximity
 
     // If filtering with region proximity results in zero faces,
     // revert to face-only proximity filter
-    if (returnReduce(acceptFaces.none(), andOp<bool>()))
+    if (returnReduceAnd(acceptFaces.none()))
     {
         acceptFaces.reset();
         prune = false;
diff --git a/src/sampling/surface/isoSurface/isoSurfaceTopo.C b/src/sampling/surface/isoSurface/isoSurfaceTopo.C
index c688256546..68a1c831f1 100644
--- a/src/sampling/surface/isoSurface/isoSurfaceTopo.C
+++ b/src/sampling/surface/isoSurface/isoSurfaceTopo.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2019 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -1587,7 +1587,7 @@ Foam::isoSurfaceTopo::isoSurfaceTopo
                     << " faces on " << nEdgeRemove << " open edges" << endl;
             }
 
-            if (returnReduce(faceSelection.none(), andOp<bool>()))
+            if (returnReduceAnd(faceSelection.none()))
             {
                 break;
             }
diff --git a/src/surfMesh/polySurface/polySurface.C b/src/surfMesh/polySurface/polySurface.C
index a5d8434d4a..2adf49d0b3 100644
--- a/src/surfMesh/polySurface/polySurface.C
+++ b/src/surfMesh/polySurface/polySurface.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -43,7 +43,7 @@ const Foam::word Foam::polySurface::pointDataName("PointData");
 
 void Foam::polySurface::calculateZoneIds(const UList<surfZone>& zones)
 {
-    if (returnReduce(zones.empty(), andOp<bool>()))
+    if (returnReduceAnd(zones.empty()))
     {
         zoneIds_.clear();
         return;
diff --git a/src/surfMesh/writers/common/surfaceWriter.C b/src/surfMesh/writers/common/surfaceWriter.C
index 71d7df16e2..e8868dcd61 100644
--- a/src/surfMesh/writers/common/surfaceWriter.C
+++ b/src/surfMesh/writers/common/surfaceWriter.C
@@ -401,7 +401,7 @@ bool Foam::surfaceWriter::empty() const
 {
     const bool value = surf_.faces().empty();
 
-    return (parallel_ ? returnReduce(value, andOp<bool>()) : value);
+    return (parallel_ ? returnReduceAnd(value) : value);
 }
 
 
diff --git a/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceReflecting/faceReflecting.C b/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceReflecting/faceReflecting.C
index 2013255abc..3c35995bf0 100644
--- a/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceReflecting/faceReflecting.C
+++ b/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceReflecting/faceReflecting.C
@@ -375,7 +375,7 @@ void Foam::faceReflecting::calculate()
             }
         }
 
-    }while (returnReduce(i < Cfs_->size(), orOp<bool>()));
+    } while (returnReduceOr(i < Cfs_->size()));
 
     List<pointIndexHit> hitInfo(startIndex.size());
 
diff --git a/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceShading/faceShading.C b/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceShading/faceShading.C
index 95253efbc7..6395e426dc 100644
--- a/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceShading/faceShading.C
+++ b/src/thermophysicalModels/radiation/radiationModels/solarLoad/faceShading/faceShading.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015 OpenFOAM Foundation
-    Copyright (C) 2017-2019 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -177,12 +177,8 @@ void Foam::faceShading::calculate()
         }
     }
 
-    label numberPotentialHits = nFaces;
-
-    reduce(numberPotentialHits, sumOp<label>());
-
     Info<< "Number of 'potential' direct hits : "
-        << numberPotentialHits << endl;
+        << returnReduce(nFaces, sumOp<label>()) << endl;
 
     labelList hitFacesIds(nFaces);
     hitFacesIds.transfer(dynFacesI);
@@ -301,7 +297,7 @@ void Foam::faceShading::calculate()
 
             }
 
-        }while (returnReduce(i < Cfs.size(), orOp<bool>()));
+        } while (returnReduceOr(i < Cfs.size()));
 
         List<pointIndexHit> hitInfo(startIndex.size());
         surfacesMesh.findLine(start, end, hitInfo);
@@ -367,11 +363,8 @@ void Foam::faceShading::calculate()
         hitFaces.write();
     }
 
-    label totalHitFaces = rayStartFaces_.size();
-
-    reduce(totalHitFaces, sumOp<label>());
-
-    Info<< "Total number of hit faces : " <<  totalHitFaces << endl;
+    Info<< "Total number of hit faces : "
+        << returnReduce(rayStartFaces_.size(), sumOp<label>()) << endl;
 }
 
 
diff --git a/src/thermophysicalModels/radiation/radiationModels/solarLoad/solarLoad.C b/src/thermophysicalModels/radiation/radiationModels/solarLoad/solarLoad.C
index 9aab8a5795..aaf4011c9b 100644
--- a/src/thermophysicalModels/radiation/radiationModels/solarLoad/solarLoad.C
+++ b/src/thermophysicalModels/radiation/radiationModels/solarLoad/solarLoad.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -473,8 +473,8 @@ void Foam::radiation::solarLoad::calculateQdiff
         nLocalVFCoarseFaces += coarseMesh_->boundaryMesh()[patchI].size();
     }
 
-    label totalFVNCoarseFaces = nLocalVFCoarseFaces;
-    reduce(totalFVNCoarseFaces, sumOp<label>());
+    const label totalFVNCoarseFaces =
+        returnReduce(nLocalVFCoarseFaces, sumOp<label>());
 
     // Calculate weighted absorptivity on coarse patches
     List<scalar> localCoarseEave(nLocalVFCoarseFaces);
diff --git a/src/thermophysicalModels/radiation/radiationModels/viewFactor/viewFactor.C b/src/thermophysicalModels/radiation/radiationModels/viewFactor/viewFactor.C
index 4ead682bbb..7e9bc5a010 100644
--- a/src/thermophysicalModels/radiation/radiationModels/viewFactor/viewFactor.C
+++ b/src/thermophysicalModels/radiation/radiationModels/viewFactor/viewFactor.C
@@ -103,8 +103,7 @@ void Foam::radiation::viewFactor::initialise()
             << nLocalCoarseFaces_ << endl;
     }
 
-    totalNCoarseFaces_ = nLocalCoarseFaces_;
-    reduce(totalNCoarseFaces_, sumOp<label>());
+    totalNCoarseFaces_ = returnReduce(nLocalCoarseFaces_, sumOp<label>());
 
     DebugInFunction
         << "Total number of clusters : " << totalNCoarseFaces_ << endl;