[Flang][OpenMP]Support for lowering task_reduction and in_reduction to MLIR

flang/lib/Lower/OpenMP/ClauseProcessor.cpp

@@ -916,6 +916,30 @@ bool ClauseProcessor::processIsDevicePtr(
       });
 }
 
+bool ClauseProcessor::processInReduction(
+    mlir::Location currentLocation, mlir::omp::InReductionClauseOps &result,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &outReductionSyms) const {
+  return findRepeatableClause<omp::clause::InReduction>(
+      [&](const omp::clause::InReduction &clause, const parser::CharBlock &) {
+        llvm::SmallVector<mlir::Value> inReductionVars;
+        llvm::SmallVector<bool> inReduceVarByRef;
+        llvm::SmallVector<mlir::Attribute> inReductionDeclSymbols;
+        llvm::SmallVector<const semantics::Symbol *> inReductionSyms;
+        ReductionProcessor rp;
+        rp.addDeclareReduction<omp::clause::InReduction>(
+            currentLocation, converter, clause, inReductionVars,
+            inReduceVarByRef, inReductionDeclSymbols, inReductionSyms);
+
+        // Copy local lists into the output.
+        llvm::copy(inReductionVars, std::back_inserter(result.inReductionVars));
+        llvm::copy(inReduceVarByRef,
+                   std::back_inserter(result.inReductionByref));
+        llvm::copy(inReductionDeclSymbols,
+                   std::back_inserter(result.inReductionSyms));
+        llvm::copy(inReductionSyms, std::back_inserter(outReductionSyms));
+      });
+}
+
 bool ClauseProcessor::processLink(
     llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const {
   return findRepeatableClause<omp::clause::Link>(
@@ -1126,9 +1150,10 @@ bool ClauseProcessor::processReduction(
         llvm::SmallVector<mlir::Attribute> reductionDeclSymbols;
         llvm::SmallVector<const semantics::Symbol *> reductionSyms;
         ReductionProcessor rp;
-        rp.addDeclareReduction(currentLocation, converter, clause,
-                               reductionVars, reduceVarByRef,
-                               reductionDeclSymbols, reductionSyms);
+
+        rp.addDeclareReduction<omp::clause::Reduction>(
+            currentLocation, converter, clause, reductionVars, reduceVarByRef,
+            reductionDeclSymbols, reductionSyms);
 
         // Copy local lists into the output.
         llvm::copy(reductionVars, std::back_inserter(result.reductionVars));
@@ -1139,6 +1164,30 @@ bool ClauseProcessor::processReduction(
       });
 }
 
+bool ClauseProcessor::processTaskReduction(
+    mlir::Location currentLocation, mlir::omp::TaskReductionClauseOps &result,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &outReductionSyms) const {
+  return findRepeatableClause<omp::clause::TaskReduction>(
+      [&](const omp::clause::TaskReduction &clause, const parser::CharBlock &) {
+        llvm::SmallVector<mlir::Value> taskReductionVars;
+        llvm::SmallVector<bool> TaskReduceVarByRef;
+        llvm::SmallVector<mlir::Attribute> TaskReductionDeclSymbols;
+        llvm::SmallVector<const semantics::Symbol *> TaskReductionSyms;
+        ReductionProcessor rp;
+        rp.addDeclareReduction<omp::clause::TaskReduction>(
+            currentLocation, converter, clause, taskReductionVars,
+            TaskReduceVarByRef, TaskReductionDeclSymbols, TaskReductionSyms);
+        // Copy local lists into the output.
+        llvm::copy(taskReductionVars,
+                   std::back_inserter(result.taskReductionVars));
+        llvm::copy(TaskReduceVarByRef,
+                   std::back_inserter(result.taskReductionByref));
+        llvm::copy(TaskReductionDeclSymbols,
+                   std::back_inserter(result.taskReductionSyms));
+        llvm::copy(TaskReductionSyms, std::back_inserter(outReductionSyms));
+      });
+}
+
 bool ClauseProcessor::processTo(
     llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const {
   return findRepeatableClause<omp::clause::To>(

flang/lib/Lower/OpenMP/ClauseProcessor.h

@@ -105,6 +105,9 @@ class ClauseProcessor {
   bool processIsDevicePtr(
       mlir::omp::IsDevicePtrClauseOps &result,
       llvm::SmallVectorImpl<const semantics::Symbol *> &isDeviceSyms) const;
+  bool processInReduction(
+      mlir::Location currentLocation, mlir::omp::InReductionClauseOps &result,
+      llvm::SmallVectorImpl<const semantics::Symbol *> &outReductionSyms) const;
   bool
   processLink(llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const;
 
@@ -123,6 +126,9 @@ class ClauseProcessor {
   bool processReduction(
       mlir::Location currentLocation, mlir::omp::ReductionClauseOps &result,
       llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSyms) const;
+  bool processTaskReduction(
+      mlir::Location currentLocation, mlir::omp::TaskReductionClauseOps &result,
+      llvm::SmallVectorImpl<const semantics::Symbol *> &outReductionSyms) const;
   bool processTo(llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const;
   bool processUseDeviceAddr(
       lower::StatementContext &stmtCtx,

flang/lib/Lower/OpenMP/DataSharingProcessor.cpp

@@ -344,8 +344,15 @@ void DataSharingProcessor::collectSymbols(
   // Collect all symbols referenced in the evaluation being processed,
   // that matches 'flag'.
   llvm::SetVector<const semantics::Symbol *> allSymbols;
+
+  auto itr = llvm::find_if(clauses, [](const omp::Clause &clause) {
+    return clause.id == llvm::omp::Clause::OMPC_in_reduction;
+  });
+
+  bool collectSymbols = (itr == clauses.end());
+
   converter.collectSymbolSet(eval, allSymbols, flag,
-                             /*collectSymbols=*/true,
+                             /*collectSymbols=*/collectSymbols,
                              /*collectHostAssociatedSymbols=*/true);
 
   llvm::SetVector<const semantics::Symbol *> symbolsInNestedRegions;

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -1249,34 +1249,34 @@ static void genTargetEnterExitUpdateDataClauses(
   cp.processNowait(clauseOps);
 }
 
-static void genTaskClauses(lower::AbstractConverter &converter,
-                           semantics::SemanticsContext &semaCtx,
-                           lower::StatementContext &stmtCtx,
-                           const List<Clause> &clauses, mlir::Location loc,
-                           mlir::omp::TaskOperands &clauseOps) {
+static void genTaskClauses(
+    lower::AbstractConverter &converter, semantics::SemanticsContext &semaCtx,
+    lower::StatementContext &stmtCtx, const List<Clause> &clauses,
+    mlir::Location loc, mlir::omp::TaskOperands &clauseOps,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &inReductionSyms) {
   ClauseProcessor cp(converter, semaCtx, clauses);
   cp.processAllocate(clauseOps);
   cp.processDepend(clauseOps);
   cp.processFinal(stmtCtx, clauseOps);
   cp.processIf(llvm::omp::Directive::OMPD_task, clauseOps);
+  cp.processInReduction(loc, clauseOps, inReductionSyms);
   cp.processMergeable(clauseOps);
   cp.processPriority(stmtCtx, clauseOps);
   cp.processUntied(clauseOps);
   cp.processDetach(clauseOps);
   // TODO Support delayed privatization.
 
-  cp.processTODO<clause::Affinity, clause::InReduction>(
-      loc, llvm::omp::Directive::OMPD_task);
+  cp.processTODO<clause::Affinity>(loc, llvm::omp::Directive::OMPD_task);
 }
 
-static void genTaskgroupClauses(lower::AbstractConverter &converter,
-                                semantics::SemanticsContext &semaCtx,
-                                const List<Clause> &clauses, mlir::Location loc,
-                                mlir::omp::TaskgroupOperands &clauseOps) {
+static void genTaskgroupClauses(
+    lower::AbstractConverter &converter, semantics::SemanticsContext &semaCtx,
+    const List<Clause> &clauses, mlir::Location loc,
+    mlir::omp::TaskgroupOperands &clauseOps,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &taskReductionSyms) {
   ClauseProcessor cp(converter, semaCtx, clauses);
   cp.processAllocate(clauseOps);
-  cp.processTODO<clause::TaskReduction>(loc,
-                                        llvm::omp::Directive::OMPD_taskgroup);
+  cp.processTaskReduction(loc, clauseOps, taskReductionSyms);
 }
 
 static void genTaskwaitClauses(lower::AbstractConverter &converter,
@@ -1887,7 +1887,9 @@ genTaskOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
           ConstructQueue::const_iterator item) {
   lower::StatementContext stmtCtx;
   mlir::omp::TaskOperands clauseOps;
-  genTaskClauses(converter, semaCtx, stmtCtx, item->clauses, loc, clauseOps);
+  llvm::SmallVector<const semantics::Symbol *> inReductionSyms;
+  genTaskClauses(converter, semaCtx, stmtCtx, item->clauses, loc, clauseOps,
+                 inReductionSyms);
 
   if (!enableDelayedPrivatization)
     return genOpWithBody<mlir::omp::TaskOp>(
@@ -1904,22 +1906,27 @@ genTaskOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
   EntryBlockArgs taskArgs;
   taskArgs.priv.syms = dsp.getDelayedPrivSymbols();
   taskArgs.priv.vars = clauseOps.privateVars;
+  taskArgs.inReduction.syms = inReductionSyms;
+  taskArgs.inReduction.vars = clauseOps.inReductionVars;
 
   auto genRegionEntryCB = [&](mlir::Operation *op) {
     genEntryBlock(converter.getFirOpBuilder(), taskArgs, op->getRegion(0));
     bindEntryBlockArgs(converter,
                        llvm::cast<mlir::omp::BlockArgOpenMPOpInterface>(op),
                        taskArgs);
-    return llvm::to_vector(taskArgs.priv.syms);
+    return llvm::to_vector(taskArgs.getSyms());
   };
 
-  return genOpWithBody<mlir::omp::TaskOp>(
+  OpWithBodyGenInfo genInfo =
       OpWithBodyGenInfo(converter, symTable, semaCtx, loc, eval,
                         llvm::omp::Directive::OMPD_task)
           .setClauses(&item->clauses)
           .setDataSharingProcessor(&dsp)
-          .setGenRegionEntryCb(genRegionEntryCB),
-      queue, item, clauseOps);
+          .setGenRegionEntryCb(genRegionEntryCB);
+
+  auto taskOp =
+      genOpWithBody<mlir::omp::TaskOp>(genInfo, queue, item, clauseOps);
+  return taskOp;
 }
 
 static mlir::omp::TaskgroupOp
@@ -1929,13 +1936,28 @@ genTaskgroupOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
                const ConstructQueue &queue,
                ConstructQueue::const_iterator item) {
   mlir::omp::TaskgroupOperands clauseOps;
-  genTaskgroupClauses(converter, semaCtx, item->clauses, loc, clauseOps);
+  llvm::SmallVector<const semantics::Symbol *> taskReductionSyms;
+  genTaskgroupClauses(converter, semaCtx, item->clauses, loc, clauseOps,
+                      taskReductionSyms);
 
-  return genOpWithBody<mlir::omp::TaskgroupOp>(
+  EntryBlockArgs taskgroupArgs;
+  taskgroupArgs.taskReduction.syms = taskReductionSyms;
+  taskgroupArgs.taskReduction.vars = clauseOps.taskReductionVars;
+
+  auto genRegionEntryCB = [&](mlir::Operation *op) {
+    genEntryBlock(converter.getFirOpBuilder(), taskgroupArgs, op->getRegion(0));
+    return llvm::to_vector(taskgroupArgs.getSyms());
+  };
+
+  OpWithBodyGenInfo genInfo =
       OpWithBodyGenInfo(converter, symTable, semaCtx, loc, eval,
                         llvm::omp::Directive::OMPD_taskgroup)
-          .setClauses(&item->clauses),
-      queue, item, clauseOps);
+          .setClauses(&item->clauses)
+          .setGenRegionEntryCb(genRegionEntryCB);
+
+  auto taskgroupOp =
+      genOpWithBody<mlir::omp::TaskgroupOp>(genInfo, queue, item, clauseOps);
+  return taskgroupOp;
 }
 
 static mlir::omp::TaskwaitOp

flang/lib/Lower/OpenMP/ReductionProcessor.cpp

@@ -24,6 +24,7 @@
 #include "flang/Parser/tools.h"
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
 #include "llvm/Support/CommandLine.h"
+#include <type_traits>
 
 static llvm::cl::opt<bool> forceByrefReduction(
     "force-byref-reduction",
@@ -34,6 +35,32 @@ namespace Fortran {
 namespace lower {
 namespace omp {
 
+// explicit template declarations
+template void ReductionProcessor::addDeclareReduction<omp::clause::Reduction>(
+    mlir::Location currentLocation, lower::AbstractConverter &converter,
+    const omp::clause::Reduction &reduction,
+    llvm::SmallVectorImpl<mlir::Value> &reductionVars,
+    llvm::SmallVectorImpl<bool> &reduceVarByRef,
+    llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols);
+
+template void
+ReductionProcessor::addDeclareReduction<omp::clause::TaskReduction>(
+    mlir::Location currentLocation, lower::AbstractConverter &converter,
+    const omp::clause::TaskReduction &reduction,
+    llvm::SmallVectorImpl<mlir::Value> &reductionVars,
+    llvm::SmallVectorImpl<bool> &reduceVarByRef,
+    llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols);
+
+template void ReductionProcessor::addDeclareReduction<omp::clause::InReduction>(
+    mlir::Location currentLocation, lower::AbstractConverter &converter,
+    const omp::clause::InReduction &reduction,
+    llvm::SmallVectorImpl<mlir::Value> &reductionVars,
+    llvm::SmallVectorImpl<bool> &reduceVarByRef,
+    llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
+    llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols);
+
 ReductionProcessor::ReductionIdentifier ReductionProcessor::getReductionType(
     const omp::clause::ProcedureDesignator &pd) {
   auto redType = llvm::StringSwitch<std::optional<ReductionIdentifier>>(
@@ -716,22 +743,22 @@ static bool doReductionByRef(mlir::Value reductionVar) {
   return false;
 }
 
+template <class T>
 void ReductionProcessor::addDeclareReduction(
     mlir::Location currentLocation, lower::AbstractConverter &converter,
-    const omp::clause::Reduction &reduction,
-    llvm::SmallVectorImpl<mlir::Value> &reductionVars,
+    const T &reduction, llvm::SmallVectorImpl<mlir::Value> &reductionVars,
     llvm::SmallVectorImpl<bool> &reduceVarByRef,
     llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
     llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols) {
   fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
-
-  if (std::get<std::optional<omp::clause::Reduction::ReductionModifier>>(
-          reduction.t))
-    TODO(currentLocation, "Reduction modifiers are not supported");
+  if constexpr (std::is_same<T, omp::clause::Reduction>::value) {
+    if (std::get<std::optional<typename T::ReductionModifier>>(reduction.t))
+      TODO(currentLocation, "Reduction modifiers are not supported");
+  }
 
   mlir::omp::DeclareReductionOp decl;
   const auto &redOperatorList{
-      std::get<omp::clause::Reduction::ReductionIdentifiers>(reduction.t)};
+      std::get<typename T::ReductionIdentifiers>(reduction.t)};
   assert(redOperatorList.size() == 1 && "Expecting single operator");
   const auto &redOperator = redOperatorList.front();
   const auto &objectList{std::get<omp::ObjectList>(reduction.t)};

flang/lib/Lower/OpenMP/ReductionProcessor.h

@@ -120,10 +120,10 @@ class ReductionProcessor {
 
   /// Creates a reduction declaration and associates it with an OpenMP block
   /// directive.
+  template <class T>
   static void addDeclareReduction(
       mlir::Location currentLocation, lower::AbstractConverter &converter,
-      const omp::clause::Reduction &reduction,
-      llvm::SmallVectorImpl<mlir::Value> &reductionVars,
+      const T &reduction, llvm::SmallVectorImpl<mlir::Value> &reductionVars,
       llvm::SmallVectorImpl<bool> &reduceVarByRef,
       llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
       llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols);

flang/test/Lower/OpenMP/task-inreduction.f90

@@ -0,0 +1,35 @@
+! RUN: bbc -emit-hlfir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+
+!CHECK-LABEL: omp.declare_reduction
+!CHECK-SAME:  @[[RED_I32_NAME:.*]] : i32 init {
+!CHECK:       ^bb0(%{{.*}}: i32):
+!CHECK:         %[[C0_1:.*]] = arith.constant 0 : i32
+!CHECK:         omp.yield(%[[C0_1]] : i32)
+!CHECK:       } combiner {
+!CHECK:       ^bb0(%[[ARG0:.*]]: i32, %[[ARG1:.*]]: i32):
+!CHECK:          %[[RES:.*]] = arith.addi %[[ARG0]], %[[ARG1]] : i32
+!CHECK:          omp.yield(%[[RES]] : i32)
+!CHECK:         }
+
+!CHECK-LABEL:  func.func @_QPomp_task_in_reduction() {
+!                [...]
+!CHECK:          omp.task in_reduction(@[[RED_I32_NAME]] %[[VAL_1:.*]]#0  -> %[[ARG0]] : !fir.ref<i32>) {
+!CHECK:            %[[VAL_4:.*]]:2 = hlfir.declare %[[ARG0]]
+!CHECK-SAME:       {uniq_name = "_QFomp_task_in_reductionEi"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK:            %[[VAL_5:.*]] = fir.load %[[VAL_4]]#0 : !fir.ref<i32>
+!CHECK:            %[[VAL_6:.*]] = arith.constant 1 : i32
+!CHECK:            %[[VAL_7:.*]] = arith.addi %[[VAL_5]], %[[VAL_6]] : i32
+!CHECK:            hlfir.assign %[[VAL_7]] to %[[VAL_4]]#0 : i32, !fir.ref<i32>
+!CHECK:            omp.terminator
+!CHECK:           }
+!CHECK:           return
+!CHECK:          }
+
+subroutine omp_task_in_reduction()
+   integer i
+   i = 0
+   !$omp task in_reduction(+:i)
+   i = i + 1
+   !$omp end task
+end subroutine omp_task_in_reduction