diff --git a/flang/lib/Lower/OpenMP/ClauseProcessor.h b/flang/lib/Lower/OpenMP/ClauseProcessor.h
index ffa8a5e055938..9af9b010ae56d 100644
--- a/flang/lib/Lower/OpenMP/ClauseProcessor.h
+++ b/flang/lib/Lower/OpenMP/ClauseProcessor.h
@@ -46,13 +46,11 @@ namespace omp {
 /// methods that relate to clauses that can impact the lowering of that
 /// construct.
 class ClauseProcessor {
-  using ClauseTy = Fortran::parser::OmpClause;
-
 public:
   ClauseProcessor(Fortran::lower::AbstractConverter &converter,
                   Fortran::semantics::SemanticsContext &semaCtx,
                   const Fortran::parser::OmpClauseList &clauses)
-      : converter(converter), semaCtx(semaCtx), clauses2(clauses),
+      : converter(converter), semaCtx(semaCtx),
         clauses(makeList(clauses, semaCtx)) {}
 
   // 'Unique' clauses: They can appear at most once in the clause list.
@@ -157,7 +155,6 @@ class ClauseProcessor {
 
 private:
   using ClauseIterator = List<Clause>::const_iterator;
-  using ClauseIterator2 = std::list<ClauseTy>::const_iterator;
 
   /// Utility to find a clause within a range in the clause list.
   template <typename T>
@@ -183,7 +180,6 @@ class ClauseProcessor {
 
   Fortran::lower::AbstractConverter &converter;
   Fortran::semantics::SemanticsContext &semaCtx;
-  const Fortran::parser::OmpClauseList &clauses2;
   List<Clause> clauses;
 };
 
@@ -239,19 +235,17 @@ bool ClauseProcessor::processMotionClauses(
 template <typename... Ts>
 void ClauseProcessor::processTODO(mlir::Location currentLocation,
                                   llvm::omp::Directive directive) const {
-  auto checkUnhandledClause = [&](const auto *x) {
+  auto checkUnhandledClause = [&](llvm::omp::Clause id, const auto *x) {
     if (!x)
       return;
     TODO(currentLocation,
-         "Unhandled clause " +
-             llvm::StringRef(Fortran::parser::ParseTreeDumper::GetNodeName(*x))
-                 .upper() +
+         "Unhandled clause " + llvm::omp::getOpenMPClauseName(id).upper() +
              " in " + llvm::omp::getOpenMPDirectiveName(directive).upper() +
              " construct");
   };
 
-  for (ClauseIterator2 it = clauses2.v.begin(); it != clauses2.v.end(); ++it)
-    (checkUnhandledClause(std::get_if<Ts>(&it->u)), ...);
+  for (ClauseIterator it = clauses.begin(); it != clauses.end(); ++it)
+    (checkUnhandledClause(it->id, std::get_if<Ts>(&it->u)), ...);
 }
 
 template <typename T>
diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index d335129565b4e..07aa63d3378bc 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -756,9 +756,7 @@ genTaskOp(Fortran::lower::AbstractConverter &converter,
   cp.processMergeable(mergeableAttr);
   cp.processPriority(stmtCtx, priorityClauseOperand);
   cp.processDepend(dependTypeOperands, dependOperands);
-  cp.processTODO<Fortran::parser::OmpClause::InReduction,
-                 Fortran::parser::OmpClause::Detach,
-                 Fortran::parser::OmpClause::Affinity>(
+  cp.processTODO<clause::InReduction, clause::Detach, clause::Affinity>(
       currentLocation, llvm::omp::Directive::OMPD_task);
 
   return genOpWithBody<mlir::omp::TaskOp>(
@@ -784,8 +782,8 @@ genTaskgroupOp(Fortran::lower::AbstractConverter &converter,
   llvm::SmallVector<mlir::Value> allocateOperands, allocatorOperands;
   ClauseProcessor cp(converter, semaCtx, clauseList);
   cp.processAllocate(allocatorOperands, allocateOperands);
-  cp.processTODO<Fortran::parser::OmpClause::TaskReduction>(
-      currentLocation, llvm::omp::Directive::OMPD_taskgroup);
+  cp.processTODO<clause::TaskReduction>(currentLocation,
+                                        llvm::omp::Directive::OMPD_taskgroup);
   return genOpWithBody<mlir::omp::TaskgroupOp>(
       OpWithBodyGenInfo(converter, semaCtx, currentLocation, eval)
           .setGenNested(genNested)
@@ -1124,16 +1122,11 @@ genTargetOp(Fortran::lower::AbstractConverter &converter,
   cp.processMap(currentLocation, directive, stmtCtx, mapOperands, &mapSymTypes,
                 &mapSymLocs, &mapSymbols);
 
-  cp.processTODO<Fortran::parser::OmpClause::Private,
-                 Fortran::parser::OmpClause::Firstprivate,
-                 Fortran::parser::OmpClause::IsDevicePtr,
-                 Fortran::parser::OmpClause::HasDeviceAddr,
-                 Fortran::parser::OmpClause::Reduction,
-                 Fortran::parser::OmpClause::InReduction,
-                 Fortran::parser::OmpClause::Allocate,
-                 Fortran::parser::OmpClause::UsesAllocators,
-                 Fortran::parser::OmpClause::Defaultmap>(
+  cp.processTODO<clause::Private, clause::Firstprivate, clause::IsDevicePtr,
+                 clause::HasDeviceAddr, clause::Reduction, clause::InReduction,
+                 clause::Allocate, clause::UsesAllocators, clause::Defaultmap>(
       currentLocation, llvm::omp::Directive::OMPD_target);
+
   // 5.8.1 Implicit Data-Mapping Attribute Rules
   // The following code follows the implicit data-mapping rules to map all the
   // symbols used inside the region that have not been explicitly mapped using
@@ -1252,8 +1245,8 @@ genTeamsOp(Fortran::lower::AbstractConverter &converter,
   cp.processDefault();
   cp.processNumTeams(stmtCtx, numTeamsClauseOperand);
   cp.processThreadLimit(stmtCtx, threadLimitClauseOperand);
-  cp.processTODO<Fortran::parser::OmpClause::Reduction>(
-      currentLocation, llvm::omp::Directive::OMPD_teams);
+  cp.processTODO<clause::Reduction>(currentLocation,
+                                    llvm::omp::Directive::OMPD_teams);
 
   return genOpWithBody<mlir::omp::TeamsOp>(
       OpWithBodyGenInfo(converter, semaCtx, currentLocation, eval)
@@ -1305,9 +1298,8 @@ static mlir::omp::DeclareTargetDeviceType getDeclareTargetInfo(
     cp.processEnter(symbolAndClause);
     cp.processLink(symbolAndClause);
     cp.processDeviceType(deviceType);
-    cp.processTODO<Fortran::parser::OmpClause::Indirect>(
-        converter.getCurrentLocation(),
-        llvm::omp::Directive::OMPD_declare_target);
+    cp.processTODO<clause::Indirect>(converter.getCurrentLocation(),
+                                     llvm::omp::Directive::OMPD_declare_target);
   }
 
   return deviceType;
@@ -1389,8 +1381,7 @@ genOmpSimpleStandalone(Fortran::lower::AbstractConverter &converter,
     break;
   case llvm::omp::Directive::OMPD_taskwait:
     ClauseProcessor(converter, semaCtx, opClauseList)
-        .processTODO<Fortran::parser::OmpClause::Depend,
-                     Fortran::parser::OmpClause::Nowait>(
+        .processTODO<clause::Depend, clause::Nowait>(
             currentLocation, llvm::omp::Directive::OMPD_taskwait);
     firOpBuilder.create<mlir::omp::TaskwaitOp>(currentLocation);
     break;
@@ -1592,11 +1583,8 @@ createSimdLoop(Fortran::lower::AbstractConverter &converter,
   cp.processIf(clause::If::DirectiveNameModifier::Simd, ifClauseOperand);
   cp.processSimdlen(simdlenClauseOperand);
   cp.processSafelen(safelenClauseOperand);
-  cp.processTODO<Fortran::parser::OmpClause::Aligned,
-                 Fortran::parser::OmpClause::Allocate,
-                 Fortran::parser::OmpClause::Linear,
-                 Fortran::parser::OmpClause::Nontemporal,
-                 Fortran::parser::OmpClause::Order>(loc, ompDirective);
+  cp.processTODO<clause::Aligned, clause::Allocate, clause::Linear,
+                 clause::Nontemporal, clause::Order>(loc, ompDirective);
 
   convertLoopBounds(converter, loc, lowerBound, upperBound, step,
                     loopVarTypeSize);
@@ -1653,8 +1641,7 @@ static void createWsloop(Fortran::lower::AbstractConverter &converter,
   cp.processScheduleChunk(stmtCtx, scheduleChunkClauseOperand);
   cp.processReduction(loc, reductionVars, reductionDeclSymbols,
                       &reductionSymbols);
-  cp.processTODO<Fortran::parser::OmpClause::Linear,
-                 Fortran::parser::OmpClause::Order>(loc, ompDirective);
+  cp.processTODO<clause::Linear, clause::Order>(loc, ompDirective);
 
   convertLoopBounds(converter, loc, lowerBound, upperBound, step,
                     loopVarTypeSize);
@@ -1724,11 +1711,9 @@ static void createSimdWsloop(
     const Fortran::parser::OmpClauseList &beginClauseList,
     const Fortran::parser::OmpClauseList *endClauseList, mlir::Location loc) {
   ClauseProcessor cp(converter, semaCtx, beginClauseList);
-  cp.processTODO<
-      Fortran::parser::OmpClause::Aligned, Fortran::parser::OmpClause::Allocate,
-      Fortran::parser::OmpClause::Linear, Fortran::parser::OmpClause::Safelen,
-      Fortran::parser::OmpClause::Simdlen, Fortran::parser::OmpClause::Order>(
-      loc, ompDirective);
+  cp.processTODO<clause::Aligned, clause::Allocate, clause::Linear,
+                 clause::Safelen, clause::Simdlen, clause::Order>(loc,
+                                                                  ompDirective);
   // TODO: Add support for vectorization - add vectorization hints inside loop
   // body.
   // OpenMP standard does not specify the length of vector instructions.