[Flang][OpenMP][Lower] Clause lowering cleanup (#103058)

This patch removes the `ClauseProcessor::processDefault` method due to
it having been implemented in
`DataSharingProcessor::collectDefaultSymbols` instead.

Also, some `genXyzClauses` functions are updated to avoid triggering
TODO errors for clauses not supported by the corresponding construct and
to keep alphabetical sorting on the order in which clauses are
processed.

Author: skatrak

flang/lib/Lower/OpenMP/ClauseProcessor.cpp

@@ -256,28 +256,6 @@ bool ClauseProcessor::processCollapse(
   return found;
 }
 
-bool ClauseProcessor::processDefault() const {
-  if (auto *clause = findUniqueClause<omp::clause::Default>()) {
-    // Private, Firstprivate, Shared, None
-    switch (clause->v) {
-    case omp::clause::Default::DataSharingAttribute::Shared:
-    case omp::clause::Default::DataSharingAttribute::None:
-      // Default clause with shared or none do not require any handling since
-      // Shared is the default behavior in the IR and None is only required
-      // for semantic checks.
-      break;
-    case omp::clause::Default::DataSharingAttribute::Private:
-      // TODO Support default(private)
-      break;
-    case omp::clause::Default::DataSharingAttribute::Firstprivate:
-      // TODO Support default(firstprivate)
-      break;
-    }
-    return true;
-  }
-  return false;
-}
-
 bool ClauseProcessor::processDevice(lower::StatementContext &stmtCtx,
                                     mlir::omp::DeviceClauseOps &result) const {
   const parser::CharBlock *source = nullptr;

flang/lib/Lower/OpenMP/ClauseProcessor.h

@@ -57,7 +57,6 @@ class ClauseProcessor {
   processCollapse(mlir::Location currentLocation, lower::pft::Evaluation &eval,
                   mlir::omp::LoopRelatedOps &result,
                   llvm::SmallVectorImpl<const semantics::Symbol *> &iv) const;
-  bool processDefault() const;
   bool processDevice(lower::StatementContext &stmtCtx,
                      mlir::omp::DeviceClauseOps &result) const;
   bool processDeviceType(mlir::omp::DeviceTypeClauseOps &result) const;

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -1055,8 +1055,9 @@ static void genFlushClauses(lower::AbstractConverter &converter,
   if (!objects.empty())
     genObjectList(objects, converter, operandRange);
 
-  if (!clauses.empty())
-    TODO(converter.getCurrentLocation(), "Handle OmpMemoryOrderClause");
+  ClauseProcessor cp(converter, semaCtx, clauses);
+  cp.processTODO<clause::AcqRel, clause::Acquire, clause::Release,
+                 clause::SeqCst>(loc, llvm::omp::OMPD_flush);
 }
 
 static void
@@ -1096,7 +1097,6 @@ static void genParallelClauses(
     llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSyms) {
   ClauseProcessor cp(converter, semaCtx, clauses);
   cp.processAllocate(clauseOps);
-  cp.processDefault();
   cp.processIf(llvm::omp::Directive::OMPD_parallel, clauseOps);
   cp.processNumThreads(stmtCtx, clauseOps);
   cp.processProcBind(clauseOps);
@@ -1129,7 +1129,7 @@ static void genSimdClauses(lower::AbstractConverter &converter,
   cp.processSimdlen(clauseOps);
 
   // TODO Support delayed privatization.
-  cp.processTODO<clause::Allocate, clause::Linear, clause::Nontemporal>(
+  cp.processTODO<clause::Linear, clause::Nontemporal>(
       loc, llvm::omp::Directive::OMPD_simd);
 }
 
@@ -1167,15 +1167,15 @@ static void genTargetClauses(
   cp.processIsDevicePtr(clauseOps, devicePtrTypes, devicePtrLocs,
                         devicePtrSyms);
   cp.processMap(loc, stmtCtx, clauseOps, &mapSyms, &mapLocs, &mapTypes);
-  cp.processThreadLimit(stmtCtx, clauseOps);
 
   if (processHostOnlyClauses)
     cp.processNowait(clauseOps);
 
+  cp.processThreadLimit(stmtCtx, clauseOps);
+
   cp.processTODO<clause::Allocate, clause::Defaultmap, clause::Firstprivate,
-                 clause::InReduction, clause::Reduction,
-                 clause::UsesAllocators>(loc,
-                                         llvm::omp::Directive::OMPD_target);
+                 clause::InReduction, clause::UsesAllocators>(
+      loc, llvm::omp::Directive::OMPD_target);
 
   // `target private(..)` is only supported in delayed privatization mode.
   if (!enableDelayedPrivatizationStaging)
@@ -1223,14 +1223,15 @@ static void genTargetEnterExitUpdateDataClauses(
   cp.processDepend(clauseOps);
   cp.processDevice(stmtCtx, clauseOps);
   cp.processIf(directive, clauseOps);
-  cp.processNowait(clauseOps);
 
   if (directive == llvm::omp::Directive::OMPD_target_update) {
     cp.processMotionClauses<clause::To>(stmtCtx, clauseOps);
     cp.processMotionClauses<clause::From>(stmtCtx, clauseOps);
   } else {
     cp.processMap(loc, stmtCtx, clauseOps);
   }
+
+  cp.processNowait(clauseOps);
 }
 
 static void genTaskClauses(lower::AbstractConverter &converter,
@@ -1240,7 +1241,6 @@ static void genTaskClauses(lower::AbstractConverter &converter,
                            mlir::omp::TaskOperands &clauseOps) {
   ClauseProcessor cp(converter, semaCtx, clauses);
   cp.processAllocate(clauseOps);
-  cp.processDefault();
   cp.processDepend(clauseOps);
   cp.processFinal(stmtCtx, clauseOps);
   cp.processIf(llvm::omp::Directive::OMPD_task, clauseOps);
@@ -1279,7 +1279,6 @@ static void genTeamsClauses(lower::AbstractConverter &converter,
                             mlir::omp::TeamsOperands &clauseOps) {
   ClauseProcessor cp(converter, semaCtx, clauses);
   cp.processAllocate(clauseOps);
-  cp.processDefault();
   cp.processIf(llvm::omp::Directive::OMPD_teams, clauseOps);
   cp.processNumTeams(stmtCtx, clauseOps);
   cp.processThreadLimit(stmtCtx, clauseOps);