[Mlir-commits] [mlir] [mlir][OpenMP] Translate task_reduction on omp.taskgroup (PR #199565)

llvmlistbot at llvm.org llvmlistbot at llvm.org
Mon May 25 11:31:30 PDT 2026


llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-openmp

@llvm/pr-subscribers-mlir-openmp

Author: Sairudra More (Saieiei)

<details>
<summary>Changes</summary>

This is the first patch in the taskloop reduction / in_reduction support series.

Flang already parses, checks, and lowers taskloop reduction/in_reduction clauses
to OpenMP MLIR, but LLVM IR translation for the taskloop path is still
incomplete. This patch implements the prerequisite task_reduction translation
for omp.taskgroup, which is needed before taskloop in_reduction can be wired
correctly.

For each reducer on omp.taskgroup, the translation emits init and combiner
helpers from the corresponding omp.declare_reduction regions, builds the
kmp_taskred_input_t descriptor array, and calls __kmpc_taskred_init before
entering the taskgroup body.

This patch intentionally keeps reduction and in_reduction on
omp.taskloop.context unsupported. Those remain follow-up work.

Part of #<!-- -->199560.


---
Full diff: https://github.com/llvm/llvm-project/pull/199565.diff


3 Files Affected:

- (modified) mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp (+233-7) 
- (added) mlir/test/Target/LLVMIR/openmp-taskgroup-task-reduction.mlir (+129) 
- (modified) mlir/test/Target/LLVMIR/openmp-todo.mlir (+3-3) 


``````````diff
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index f0511bb4be7dd..13a1899557608 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -370,10 +370,13 @@ static LogicalResult checkImplementationStatus(Operation &op) {
         op.getReductionMod().value() != omp::ReductionModifier::defaultmod)
       result = todo("reduction with modifier");
   };
-  auto checkTaskReduction = [&todo](auto op, LogicalResult &result) {
-    if (!op.getTaskReductionVars().empty() || op.getTaskReductionByref() ||
-        op.getTaskReductionSyms())
-      result = todo("task_reduction");
+  auto checkTaskReductionByref = [&todo](auto op, LogicalResult &result) {
+    if (auto byrefAttr = op.getTaskReductionByref())
+      for (bool isByRef : *byrefAttr)
+        if (isByRef) {
+          result = todo("task_reduction with byref modifier");
+          return;
+        }
   };
   auto checkNumTeams = [&todo](auto op, LogicalResult &result) {
     if (op.hasNumTeamsMultiDim())
@@ -426,7 +429,7 @@ static LogicalResult checkImplementationStatus(Operation &op) {
       })
       .Case([&](omp::TaskgroupOp op) {
         checkAllocate(op, result);
-        checkTaskReduction(op, result);
+        checkTaskReductionByref(op, result);
       })
       .Case([&](omp::TaskwaitOp op) {
         checkDepend(op, result);
@@ -3643,6 +3646,183 @@ convertOmpTaskloopContextOp(omp::TaskloopContextOp contextOp,
   return success();
 }
 
+/// Build an outlined init helper for a task_reduction declare_reduction op.
+/// Signature: void(ptr %priv, ptr %orig). For non-byref reductions, the init
+/// region's mold argument is mapped to the value loaded from %orig, and the
+/// yielded scalar is stored into %priv.
+static llvm::Function *
+emitTaskReductionInitFn(omp::DeclareReductionOp decl, StringRef baseName,
+                        LLVM::ModuleTranslation &moduleTranslation) {
+  llvm::Module *llvmModule = moduleTranslation.getLLVMModule();
+  llvm::LLVMContext &ctx = llvmModule->getContext();
+  llvm::Type *voidTy = llvm::Type::getVoidTy(ctx);
+  llvm::Type *ptrTy = llvm::PointerType::getUnqual(ctx);
+  llvm::FunctionType *fty =
+      llvm::FunctionType::get(voidTy, {ptrTy, ptrTy}, false);
+  llvm::Function *fn =
+      llvm::Function::Create(fty, llvm::GlobalValue::InternalLinkage,
+                             baseName + ".red.init", llvmModule);
+  fn->setDoesNotRecurse();
+  fn->getArg(0)->setName("priv");
+  fn->getArg(1)->setName("orig");
+
+  llvm::BasicBlock *entry = llvm::BasicBlock::Create(ctx, "entry", fn);
+  llvm::IRBuilder<> b(entry);
+
+  llvm::Type *elemTy = moduleTranslation.convertType(decl.getType());
+  llvm::Value *origVal = b.CreateLoad(elemTy, fn->getArg(1), "omp.orig");
+  moduleTranslation.mapValue(decl.getInitializerMoldArg(), origVal);
+  SmallVector<llvm::Value *, 1> phis;
+  if (failed(inlineConvertOmpRegions(decl.getInitializerRegion(),
+                                     "omp.taskred.init", b, moduleTranslation,
+                                     &phis))) {
+    fn->eraseFromParent();
+    return nullptr;
+  }
+  assert(phis.size() == 1 &&
+         "expected one value yielded from reduction initializer");
+  b.CreateStore(phis[0], fn->getArg(0));
+  b.CreateRetVoid();
+
+  moduleTranslation.forgetMapping(decl.getInitializerRegion());
+  return fn;
+}
+
+/// Build an outlined combiner helper for a task_reduction declare_reduction op.
+/// Signature: void(ptr %lhs, ptr %rhs). For non-byref reductions, the values
+/// at *%lhs and *%rhs are loaded, fed into the combiner region, and the
+/// yielded scalar is stored back into *%lhs.
+static llvm::Function *
+emitTaskReductionCombFn(omp::DeclareReductionOp decl, StringRef baseName,
+                        LLVM::ModuleTranslation &moduleTranslation) {
+  llvm::Module *llvmModule = moduleTranslation.getLLVMModule();
+  llvm::LLVMContext &ctx = llvmModule->getContext();
+  llvm::Type *voidTy = llvm::Type::getVoidTy(ctx);
+  llvm::Type *ptrTy = llvm::PointerType::getUnqual(ctx);
+  llvm::FunctionType *fty =
+      llvm::FunctionType::get(voidTy, {ptrTy, ptrTy}, false);
+  llvm::Function *fn =
+      llvm::Function::Create(fty, llvm::GlobalValue::InternalLinkage,
+                             baseName + ".red.comb", llvmModule);
+  fn->setDoesNotRecurse();
+  fn->getArg(0)->setName("lhs");
+  fn->getArg(1)->setName("rhs");
+
+  llvm::BasicBlock *entry = llvm::BasicBlock::Create(ctx, "entry", fn);
+  llvm::IRBuilder<> b(entry);
+
+  llvm::Type *elemTy = moduleTranslation.convertType(decl.getType());
+  Block &combBlock = decl.getReductionRegion().front();
+  assert(combBlock.getNumArguments() == 2 &&
+         "expected two arguments in declare_reduction combiner");
+  llvm::Value *lhsVal = b.CreateLoad(elemTy, fn->getArg(0), "omp.lhs");
+  llvm::Value *rhsVal = b.CreateLoad(elemTy, fn->getArg(1), "omp.rhs");
+  moduleTranslation.mapValue(combBlock.getArgument(0), lhsVal);
+  moduleTranslation.mapValue(combBlock.getArgument(1), rhsVal);
+
+  SmallVector<llvm::Value *, 1> phis;
+  if (failed(inlineConvertOmpRegions(decl.getReductionRegion(),
+                                     "omp.taskred.comb", b, moduleTranslation,
+                                     &phis))) {
+    fn->eraseFromParent();
+    return nullptr;
+  }
+  assert(phis.size() == 1 &&
+         "expected one value yielded from reduction combiner");
+  b.CreateStore(phis[0], fn->getArg(0));
+  b.CreateRetVoid();
+
+  moduleTranslation.forgetMapping(decl.getReductionRegion());
+  return fn;
+}
+
+/// Emit the per-taskgroup task_reduction descriptor array and the
+/// `__kmpc_taskred_init` runtime call. Must be called with `builder` set to a
+/// point inside the taskgroup body (after `__kmpc_taskgroup`). The descriptor
+/// array itself is allocated at \p allocaIP.
+///
+/// Only the non-byref form is handled here. Byref task_reduction has already
+/// been rejected by `checkImplementationStatus`.
+static LogicalResult emitTaskgroupTaskReductionInit(
+    omp::TaskgroupOp tgOp, ArrayRef<omp::DeclareReductionOp> redDecls,
+    llvm::IRBuilderBase &builder, llvm::OpenMPIRBuilder::InsertPointTy allocaIP,
+    LLVM::ModuleTranslation &moduleTranslation) {
+  llvm::OpenMPIRBuilder *ompBuilder = moduleTranslation.getOpenMPBuilder();
+  llvm::Module *llvmModule = moduleTranslation.getLLVMModule();
+  llvm::LLVMContext &ctx = llvmModule->getContext();
+  const llvm::DataLayout &dl = llvmModule->getDataLayout();
+
+  llvm::Type *ptrTy = llvm::PointerType::getUnqual(ctx);
+  llvm::Type *i32Ty = llvm::Type::getInt32Ty(ctx);
+  llvm::Type *sizeTy =
+      llvm::Type::getIntNTy(ctx, dl.getPointerSizeInBits(/*AddrSpace=*/0));
+
+  // Identified `kmp_taskred_input_t` struct, matching the layout used by
+  // Clang's CGOpenMPRuntime::emitTaskReductionInit.
+  llvm::StructType *redInputTy =
+      llvm::StructType::getTypeByName(ctx, "kmp_taskred_input_t");
+  if (!redInputTy)
+    redInputTy = llvm::StructType::create(
+        ctx, {ptrTy, ptrTy, sizeTy, ptrTy, ptrTy, ptrTy, i32Ty},
+        "kmp_taskred_input_t");
+
+  unsigned n = redDecls.size();
+  llvm::ArrayType *arrTy = llvm::ArrayType::get(redInputTy, n);
+
+  // Allocate the descriptor array in the enclosing function's alloca block.
+  llvm::AllocaInst *arrAlloca;
+  {
+    llvm::IRBuilderBase::InsertPointGuard guard(builder);
+    builder.restoreIP(allocaIP);
+    arrAlloca =
+        builder.CreateAlloca(arrTy, /*ArraySize=*/nullptr, ".taskred.input");
+  }
+
+  // Fill each descriptor entry inside the taskgroup body.
+  llvm::Value *zero = builder.getInt32(0);
+  for (unsigned i = 0; i < n; ++i) {
+    omp::DeclareReductionOp decl = redDecls[i];
+    llvm::Value *orig =
+        moduleTranslation.lookupValue(tgOp.getTaskReductionVars()[i]);
+    llvm::Type *elemTy = moduleTranslation.convertType(decl.getType());
+    uint64_t size = dl.getTypeAllocSize(elemTy).getFixedValue();
+
+    std::string baseName =
+        (llvm::Twine("__omp_taskred_") + decl.getSymName()).str();
+    llvm::Function *initFn =
+        emitTaskReductionInitFn(decl, baseName, moduleTranslation);
+    llvm::Function *combFn =
+        emitTaskReductionCombFn(decl, baseName, moduleTranslation);
+    if (!initFn || !combFn)
+      return failure();
+    llvm::Value *elemPtr = builder.CreateInBoundsGEP(
+        arrTy, arrAlloca, {zero, builder.getInt32(i)}, ".taskred.elem");
+    auto storeField = [&](unsigned fieldIdx, llvm::Value *val) {
+      llvm::Value *fieldPtr =
+          builder.CreateStructGEP(redInputTy, elemPtr, fieldIdx);
+      builder.CreateStore(val, fieldPtr);
+    };
+    storeField(0, orig);                                  // reduce_shar
+    storeField(1, orig);                                  // reduce_orig
+    storeField(2, llvm::ConstantInt::get(sizeTy, size));  // reduce_size
+    storeField(3, initFn);                                // reduce_init
+    storeField(4, llvm::ConstantPointerNull::get(ptrTy)); // reduce_fini
+    storeField(5, combFn);                                // reduce_comb
+    storeField(6, llvm::ConstantInt::get(i32Ty, 0));      // flags
+  }
+
+  // Emit call: __kmpc_taskred_init(gtid, num, &arr).
+  uint32_t srcLocSize;
+  llvm::Constant *srcLocStr =
+      ompBuilder->getOrCreateDefaultSrcLocStr(srcLocSize);
+  llvm::Value *ident = ompBuilder->getOrCreateIdent(srcLocStr, srcLocSize);
+  llvm::Value *gtid = ompBuilder->getOrCreateThreadID(ident);
+  llvm::FunctionCallee taskredInit = ompBuilder->getOrCreateRuntimeFunction(
+      *llvmModule, llvm::omp::OMPRTL___kmpc_taskred_init);
+  builder.CreateCall(taskredInit, {gtid, builder.getInt32(n), arrAlloca});
+  return success();
+}
+
 /// Converts an OpenMP taskgroup construct into LLVM IR using OpenMPIRBuilder.
 static LogicalResult
 convertOmpTaskgroupOp(omp::TaskgroupOp tgOp, llvm::IRBuilderBase &builder,
@@ -3651,9 +3831,55 @@ convertOmpTaskgroupOp(omp::TaskgroupOp tgOp, llvm::IRBuilderBase &builder,
   if (failed(checkImplementationStatus(*tgOp)))
     return failure();
 
-  auto bodyCB = [&](InsertPointTy allocaIP, InsertPointTy codegenIP,
-                    llvm::ArrayRef<llvm::BasicBlock *> deallocBlocks) {
+  // Resolve and validate task_reduction declarations up front. We only handle
+  // declare_reduction ops shaped like a non-byref scalar reduction in this
+  // first cut; richer shapes (two-argument initializer, cleanup region,
+  // missing combiner) require additional infrastructure.
+  SmallVector<omp::DeclareReductionOp> redDecls;
+  if (auto syms = tgOp.getTaskReductionSyms()) {
+    redDecls.reserve(syms->size());
+    for (auto sym : syms->getAsRange<SymbolRefAttr>()) {
+      auto decl = SymbolTable::lookupNearestSymbolFrom<omp::DeclareReductionOp>(
+          tgOp, sym);
+      assert(decl && "expected task_reduction symbol to resolve");
+      if (decl.getInitializerRegion().front().getNumArguments() != 1)
+        return tgOp.emitError("not yet implemented: task_reduction with "
+                              "two-argument initializer in omp.taskgroup");
+      if (!decl.getCleanupRegion().empty())
+        return tgOp.emitError("not yet implemented: task_reduction with "
+                              "cleanup region in omp.taskgroup");
+      if (decl.getReductionRegion().empty())
+        return tgOp.emitError("task_reduction declare_reduction is missing a "
+                              "combiner region");
+      redDecls.push_back(decl);
+    }
+  }
+
+  auto bodyCB =
+      [&](InsertPointTy allocaIP, InsertPointTy codegenIP,
+          llvm::ArrayRef<llvm::BasicBlock *> deallocBlocks) -> llvm::Error {
     builder.restoreIP(codegenIP);
+
+    if (!redDecls.empty()) {
+      if (failed(emitTaskgroupTaskReductionInit(tgOp, redDecls, builder,
+                                                allocaIP, moduleTranslation)))
+        return llvm::createStringError(
+            llvm::inconvertibleErrorCode(),
+            "failed to emit task_reduction initialization for omp.taskgroup");
+    }
+
+    // Inside the taskgroup body, each task_reduction block argument refers to
+    // the same shared/original storage that the runtime now knows about via
+    // the descriptor array. Inner tasks that declare in_reduction look up
+    // per-task private copies through the runtime; the taskgroup body itself
+    // uses the original variable.
+    for (auto [i, blockArg] :
+         llvm::enumerate(tgOp.getRegion().getArguments())) {
+      llvm::Value *orig =
+          moduleTranslation.lookupValue(tgOp.getTaskReductionVars()[i]);
+      moduleTranslation.mapValue(blockArg, orig);
+    }
+
     return convertOmpOpRegions(tgOp.getRegion(), "omp.taskgroup.region",
                                builder, moduleTranslation)
         .takeError();
diff --git a/mlir/test/Target/LLVMIR/openmp-taskgroup-task-reduction.mlir b/mlir/test/Target/LLVMIR/openmp-taskgroup-task-reduction.mlir
new file mode 100644
index 0000000000000..7ad0f763cbcb1
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-taskgroup-task-reduction.mlir
@@ -0,0 +1,129 @@
+// RUN: mlir-translate -mlir-to-llvmir -split-input-file %s | FileCheck %s
+
+// Single scalar task_reduction on omp.taskgroup. Verifies that the
+// kmp_taskred_input_t descriptor is allocated, populated, and handed off to
+// __kmpc_taskred_init, and that init / combiner helper functions are emitted.
+
+omp.declare_reduction @add_i32 : i32
+init {
+^bb0(%arg0: i32):
+  %c0 = llvm.mlir.constant(0 : i32) : i32
+  omp.yield(%c0 : i32)
+}
+combiner {
+^bb0(%arg0: i32, %arg1: i32):
+  %s = llvm.add %arg0, %arg1 : i32
+  omp.yield(%s : i32)
+}
+
+llvm.func @taskgroup_task_reduction_single(%x: !llvm.ptr) {
+  omp.taskgroup task_reduction(@add_i32 %x -> %prv : !llvm.ptr) {
+    omp.terminator
+  }
+  llvm.return
+}
+
+// CHECK: %kmp_taskred_input_t = type { ptr, ptr, i64, ptr, ptr, ptr, i32 }
+
+// CHECK-LABEL: define void @taskgroup_task_reduction_single(
+// CHECK-SAME:    ptr %[[X:.+]])
+// CHECK:         %[[ARR:.+]] = alloca [1 x %kmp_taskred_input_t]
+// CHECK:         call void @__kmpc_taskgroup(
+// Descriptor entry 0.
+// CHECK:         %[[GEP0:.+]] = getelementptr inbounds [1 x %kmp_taskred_input_t], ptr %[[ARR]], i32 0, i32 0
+// CHECK:         %[[SHAR:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 0
+// CHECK:         store ptr %[[X]], ptr %[[SHAR]]
+// CHECK:         %[[ORIG:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 1
+// CHECK:         store ptr %[[X]], ptr %[[ORIG]]
+// CHECK:         %[[SZF:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 2
+// CHECK:         store i64 4, ptr %[[SZF]]
+// CHECK:         %[[INITF:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 3
+// CHECK:         store ptr @__omp_taskred_add_i32.red.init, ptr %[[INITF]]
+// CHECK:         %[[FINIF:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 4
+// CHECK:         store ptr null, ptr %[[FINIF]]
+// CHECK:         %[[COMBF:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 5
+// CHECK:         store ptr @__omp_taskred_add_i32.red.comb, ptr %[[COMBF]]
+// CHECK:         %[[FLAGSF:.+]] = getelementptr {{.+}} %kmp_taskred_input_t, ptr %[[GEP0]], i32 0, i32 6
+// CHECK:         store i32 0, ptr %[[FLAGSF]]
+// CHECK:         call ptr @__kmpc_taskred_init(i32 %{{.+}}, i32 1, ptr %[[ARR]])
+// CHECK:         call void @__kmpc_end_taskgroup(
+
+// CHECK-LABEL: define internal void @__omp_taskred_add_i32.red.init(
+// CHECK-SAME:    ptr %priv, ptr %orig)
+// CHECK:         load i32, ptr %orig
+// CHECK:         store i32 0, ptr %priv
+// CHECK:         ret void
+
+// CHECK-LABEL: define internal void @__omp_taskred_add_i32.red.comb(
+// CHECK-SAME:    ptr %lhs, ptr %rhs)
+// CHECK:         %[[L:.+]] = load i32, ptr %lhs
+// CHECK:         %[[R:.+]] = load i32, ptr %rhs
+// CHECK:         %[[S:.+]] = add i32 %[[L]], %[[R]]
+// CHECK:         store i32 %[[S]], ptr %lhs
+// CHECK:         ret void
+
+// -----
+
+// Multiple task_reduction items on the same taskgroup.
+
+omp.declare_reduction @add_i32 : i32
+init {
+^bb0(%arg0: i32):
+  %c0 = llvm.mlir.constant(0 : i32) : i32
+  omp.yield(%c0 : i32)
+}
+combiner {
+^bb0(%arg0: i32, %arg1: i32):
+  %s = llvm.add %arg0, %arg1 : i32
+  omp.yield(%s : i32)
+}
+
+omp.declare_reduction @mul_i64 : i64
+init {
+^bb0(%arg0: i64):
+  %c1 = llvm.mlir.constant(1 : i64) : i64
+  omp.yield(%c1 : i64)
+}
+combiner {
+^bb0(%arg0: i64, %arg1: i64):
+  %p = llvm.mul %arg0, %arg1 : i64
+  omp.yield(%p : i64)
+}
+
+llvm.func @taskgroup_task_reduction_multi(%x: !llvm.ptr, %y: !llvm.ptr) {
+  omp.taskgroup task_reduction(@add_i32 %x -> %a, @mul_i64 %y -> %b : !llvm.ptr, !llvm.ptr) {
+    omp.terminator
+  }
+  llvm.return
+}
+
+// CHECK-LABEL: define void @taskgroup_task_reduction_multi(
+// CHECK-SAME:    ptr %{{.+}}, ptr %{{.+}})
+// CHECK:         %[[ARR2:.+]] = alloca [2 x %kmp_taskred_input_t]
+// CHECK:         call void @__kmpc_taskgroup(
+// CHECK:         getelementptr inbounds [2 x %kmp_taskred_input_t], ptr %[[ARR2]], i32 0, i32 0
+// CHECK:         store i64 4
+// CHECK:         store ptr @__omp_taskred_add_i32.red.init
+// CHECK:         store ptr @__omp_taskred_add_i32.red.comb
+// CHECK:         getelementptr inbounds [2 x %kmp_taskred_input_t], ptr %[[ARR2]], i32 0, i32 1
+// CHECK:         store i64 8
+// CHECK:         store ptr @__omp_taskred_mul_i64.red.init
+// CHECK:         store ptr @__omp_taskred_mul_i64.red.comb
+// CHECK:         call ptr @__kmpc_taskred_init(i32 %{{.+}}, i32 2, ptr %[[ARR2]])
+
+// -----
+
+// Plain taskgroup without task_reduction must still translate (regression
+// guard for the rewrite of convertOmpTaskgroupOp).
+
+llvm.func @taskgroup_plain() {
+  omp.taskgroup {
+    omp.terminator
+  }
+  llvm.return
+}
+
+// CHECK-LABEL: define void @taskgroup_plain()
+// CHECK:         call void @__kmpc_taskgroup(
+// CHECK-NOT:     call ptr @__kmpc_taskred_init(
+// CHECK:         call void @__kmpc_end_taskgroup(
diff --git a/mlir/test/Target/LLVMIR/openmp-todo.mlir b/mlir/test/Target/LLVMIR/openmp-todo.mlir
index 295ba54dbfb38..a1cf307bf5b42 100644
--- a/mlir/test/Target/LLVMIR/openmp-todo.mlir
+++ b/mlir/test/Target/LLVMIR/openmp-todo.mlir
@@ -301,10 +301,10 @@ atomic {
   llvm.atomicrmw fadd %arg2, %2 monotonic : !llvm.ptr, f32
   omp.yield
 }
-llvm.func @taskgroup_task_reduction(%x : !llvm.ptr) {
-  // expected-error at below {{not yet implemented: Unhandled clause task_reduction in omp.taskgroup operation}}
+llvm.func @taskgroup_task_reduction_byref(%x : !llvm.ptr) {
+  // expected-error at below {{not yet implemented: Unhandled clause task_reduction with byref modifier in omp.taskgroup operation}}
   // expected-error at below {{LLVM Translation failed for operation: omp.taskgroup}}
-  omp.taskgroup task_reduction(@add_f32 %x -> %prv : !llvm.ptr) {
+  omp.taskgroup task_reduction(byref @add_f32 %x -> %prv : !llvm.ptr) {
     omp.terminator
   }
   llvm.return

``````````

</details>


https://github.com/llvm/llvm-project/pull/199565


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