[OpenMP][MLIR] Lowering task_reduction clause to LLVMIR #111788
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harishch4
requested review from
skatrak,
tblah,
kiranchandramohan,
NimishMishra,
kiranktp and
Thirumalai-Shaktivel
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@llvm/pr-subscribers-mlir-llvm @llvm/pr-subscribers-mlir-openmp Author: None (harishch4) ChangesThis patch lowers the task_reduction clause operation to LLVM IR, similar to how Clang handles it. It generates task reduction functions (red_init, red_comb, red_fini, etc.) and maps them to an internal structure, kmp_taskred_input_t, before invoking the runtime call __kmpc_taskred_init. Currently, it supports task reduction variables passed by value (VAL). A TODO has been added for handling variables passed by reference. Full diff: https://github.com/llvm/llvm-project/pull/111788.diff 3 Files Affected:
diff --git a/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td b/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
index 886554f66afffc..4a30c35549903b 100644
--- a/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
+++ b/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
@@ -1128,6 +1128,13 @@ class OpenMP_TaskReductionClauseSkip<
unsigned numTaskReductionBlockArgs() {
return getTaskReductionVars().size();
}
+
+ /// Returns the number of reduction variables.
+ unsigned getNumReductionVars() { return getReductionVars().size(); }
+
+ auto getReductionSyms() {
+ return getTaskReductionSyms();
+ }
}];
let description = [{
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 19d80fbbd699b0..d1162d6afcc4bb 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -1112,9 +1112,8 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
LogicalResult bodyGenStatus = success();
if (taskOp.getUntiedAttr() || taskOp.getMergeableAttr() ||
- taskOp.getInReductionSyms() || taskOp.getPriority() ||
- !taskOp.getAllocateVars().empty() || !taskOp.getPrivateVars().empty() ||
- taskOp.getPrivateSyms()) {
+ taskOp.getPriority() || !taskOp.getAllocateVars().empty() ||
+ !taskOp.getPrivateVars().empty() || taskOp.getPrivateSyms()) {
return taskOp.emitError("unhandled clauses for translation to LLVM IR");
}
auto bodyCB = [&](InsertPointTy allocaIP, InsertPointTy codegenIP) {
@@ -1142,19 +1141,238 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
return bodyGenStatus;
}
+template <typename OP>
+llvm::Value *createTaskReductionFunction(
+ llvm::IRBuilderBase &builder, const std::string &name, llvm::Type *redTy,
+ LLVM::ModuleTranslation &moduleTranslation,
+ SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls, Region ®ion,
+ OP &op, unsigned Cnt, llvm::ArrayRef<bool> &isByRef,
+ SmallVectorImpl<llvm::Value *> &privateReductionVariables,
+ DenseMap<Value, llvm::Value *> &reductionVariableMap) {
+ llvm::LLVMContext &Context = builder.getContext();
+ llvm::Type *OpaquePtrTy = llvm::PointerType::get(Context, 0);
+ // TODO: by-ref reduction variables are yet to be handled.
+ if (region.empty() || isByRef[Cnt]) {
+ return llvm::Constant::getNullValue(OpaquePtrTy);
+ }
+ llvm::FunctionType *funcType =
+ llvm::FunctionType::get(OpaquePtrTy, {OpaquePtrTy, OpaquePtrTy}, false);
+ llvm::Function *function =
+ llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, name,
+ builder.GetInsertBlock()->getModule());
+ function->setDoesNotRecurse();
+ llvm::BasicBlock *entry =
+ llvm::BasicBlock::Create(Context, "entry", function);
+ llvm::IRBuilder<> bbBuilder(entry);
+
+ llvm::Value *arg0 = function->getArg(0);
+ llvm::Value *arg1 = function->getArg(1);
+
+ if (name == "red_init") {
+ function->addParamAttr(0, llvm::Attribute::NoAlias);
+ function->addParamAttr(1, llvm::Attribute::NoAlias);
+ mapInitializationArgs(op, moduleTranslation, reductionDecls,
+ reductionVariableMap, Cnt);
+ } else if (name == "red_comb") {
+ llvm::Value *arg0L = bbBuilder.CreateLoad(redTy, arg0);
+ llvm::Value *arg1L = bbBuilder.CreateLoad(redTy, arg1);
+ moduleTranslation.mapValue(region.front().getArgument(0), arg0L);
+ moduleTranslation.mapValue(region.front().getArgument(1), arg1L);
+ }
+
+ SmallVector<llvm::Value *, 1> phis;
+ if (failed(inlineConvertOmpRegions(region, "", bbBuilder, moduleTranslation,
+ &phis)))
+ return nullptr;
+ assert(
+ phis.size() == 1 &&
+ "expected one value to be yielded from the reduction declaration region");
+
+ bbBuilder.CreateStore(phis[0], arg0);
+ bbBuilder.CreateRet(arg0); // Return from the function
+ return function;
+}
+
+void emitTaskRedInitCall(
+ llvm::IRBuilderBase &builder, LLVM::ModuleTranslation &moduleTranslation,
+ const llvm::OpenMPIRBuilder::LocationDescription &ompLoc, int arraySize,
+ llvm::Value *ArrayAlloca) {
+
+ llvm::LLVMContext &Context = builder.getContext();
+ uint32_t SrcLocStrSize;
+ llvm::Constant *SrcLocStr =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateSrcLocStr(ompLoc,
+ SrcLocStrSize);
+ llvm::Value *Ident = moduleTranslation.getOpenMPBuilder()->getOrCreateIdent(
+ SrcLocStr, SrcLocStrSize);
+ llvm::Value *ThreadID =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateThreadID(Ident);
+ llvm::Constant *ConstInt =
+ llvm::ConstantInt::get(llvm::Type::getInt32Ty(Context), arraySize);
+
+ llvm::Function *TaskRedInitFn =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateRuntimeFunctionPtr(
+ llvm::omp::OMPRTL___kmpc_taskred_init);
+ builder.CreateCall(TaskRedInitFn, {ThreadID, ConstInt, ArrayAlloca});
+}
+
+template <typename OP>
+static LogicalResult allocAndInitializeTaskReductionVars(
+ OP op, ArrayRef<BlockArgument> reductionArgs, llvm::IRBuilderBase &builder,
+ LLVM::ModuleTranslation &moduleTranslation,
+ llvm::OpenMPIRBuilder::InsertPointTy &allocaIP,
+ SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls,
+ SmallVectorImpl<llvm::Value *> &privateReductionVariables,
+ DenseMap<Value, llvm::Value *> &reductionVariableMap,
+ llvm::ArrayRef<bool> isByRef) {
+
+ if (op.getNumReductionVars() == 0)
+ return success();
+
+ llvm::OpenMPIRBuilder::LocationDescription ompLoc(builder);
+ llvm::LLVMContext &Context = builder.getContext();
+ SmallVector<DeferredStore> deferredStores;
+
+ // Save the current insertion point
+ auto oldIP = builder.saveIP();
+
+ // Set insertion point after the allocations
+ builder.SetInsertPoint(allocaIP.getBlock()->getTerminator());
+
+ // Define the kmp_taskred_input_t structure
+ llvm::StructType *kmp_taskred_input_t =
+ llvm::StructType::create(Context, "kmp_taskred_input_t");
+ llvm::Type *OpaquePtrTy = llvm::PointerType::get(Context, 0); // void*
+ llvm::Type *SizeTy = builder.getInt64Ty(); // size_t (assumed to be i64)
+ llvm::Type *FlagsTy = llvm::Type::getInt32Ty(Context); // flags (i32)
+
+ // Structure members
+ std::vector<llvm::Type *> structMembers = {
+ OpaquePtrTy, // reduce_shar (void*)
+ OpaquePtrTy, // reduce_orig (void*)
+ SizeTy, // reduce_size (size_t)
+ OpaquePtrTy, // reduce_init (void*)
+ OpaquePtrTy, // reduce_fini (void*)
+ OpaquePtrTy, // reduce_comb (void*)
+ FlagsTy // flags (i32)
+ };
+
+ kmp_taskred_input_t->setBody(structMembers);
+ int arraySize = op.getNumReductionVars();
+ llvm::ArrayType *ArrayTy =
+ llvm::ArrayType::get(kmp_taskred_input_t, arraySize);
+
+ // Allocate the array for kmp_taskred_input_t
+ llvm::AllocaInst *ArrayAlloca =
+ builder.CreateAlloca(ArrayTy, nullptr, "kmp_taskred_array");
+
+ // Restore the insertion point
+ builder.restoreIP(oldIP);
+ llvm::DataLayout DL = builder.GetInsertBlock()->getModule()->getDataLayout();
+
+ for (int Cnt = 0; Cnt < arraySize; ++Cnt) {
+ llvm::Value *shared =
+ moduleTranslation.lookupValue(op.getReductionVars()[Cnt]);
+ // Create a GEP to access the reduction element
+ llvm::Value *StructPtr = builder.CreateGEP(
+ ArrayTy, ArrayAlloca, {builder.getInt32(0), builder.getInt32(Cnt)},
+ "red_element");
+
+ llvm::Value *FieldPtrReduceShar = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 0, "reduce_shar");
+ builder.CreateStore(shared, FieldPtrReduceShar);
+
+ llvm::Value *FieldPtrReduceOrig = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 1, "reduce_orig");
+ builder.CreateStore(shared, FieldPtrReduceOrig);
+
+ // Store size of the reduction variable
+ llvm::Value *FieldPtrReduceSize = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 2, "reduce_size");
+ llvm::Type *redTy;
+ if (auto *alloca = dyn_cast<llvm::AllocaInst>(shared)) {
+ redTy = alloca->getAllocatedType();
+ uint64_t sizeInBytes = DL.getTypeAllocSize(redTy);
+
+ llvm::ConstantInt *sizeConst =
+ llvm::ConstantInt::get(llvm::Type::getInt64Ty(Context), sizeInBytes);
+ builder.CreateStore(sizeConst, FieldPtrReduceSize);
+ } else {
+ llvm_unreachable("Non alloca instruction found.");
+ }
+
+ // Initialize reduction variable
+ llvm::Value *FieldPtrReduceInit = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 3, "reduce_init");
+ llvm::Value *initFunction = createTaskReductionFunction(
+ builder, "red_init", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getInitializerRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(initFunction, FieldPtrReduceInit);
+
+ // Create finish and combine functions
+ llvm::Value *FieldPtrReduceFini = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 4, "reduce_fini");
+ llvm::Value *finiFunction = createTaskReductionFunction(
+ builder, "red_fini", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getCleanupRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(finiFunction, FieldPtrReduceFini);
+
+ llvm::Value *FieldPtrReduceComb = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 5, "reduce_comb");
+ llvm::Value *combFunction = createTaskReductionFunction(
+ builder, "red_comb", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getReductionRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(combFunction, FieldPtrReduceComb);
+
+ llvm::Value *FieldPtrFlags =
+ builder.CreateStructGEP(kmp_taskred_input_t, StructPtr, 6, "flags");
+ llvm::ConstantInt *flagVal =
+ llvm::ConstantInt::get(llvm::Type::getInt64Ty(Context), 0);
+ builder.CreateStore(flagVal, FieldPtrFlags);
+ }
+
+ // Emit the runtime call
+ emitTaskRedInitCall(builder, moduleTranslation, ompLoc, arraySize,
+ ArrayAlloca);
+ return success();
+}
+
/// Converts an OpenMP taskgroup construct into LLVM IR using OpenMPIRBuilder.
static LogicalResult
convertOmpTaskgroupOp(omp::TaskgroupOp tgOp, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &moduleTranslation) {
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
LogicalResult bodyGenStatus = success();
- if (!tgOp.getTaskReductionVars().empty() || !tgOp.getAllocateVars().empty()) {
+ if (!tgOp.getAllocateVars().empty()) {
return tgOp.emitError("unhandled clauses for translation to LLVM IR");
}
+
+ llvm::ArrayRef<bool> isByRef = getIsByRef(tgOp.getTaskReductionByref());
+ assert(isByRef.size() == tgOp.getNumReductionVars());
+
+ SmallVector<omp::DeclareReductionOp> reductionDecls;
+ collectReductionDecls(tgOp, reductionDecls);
+ SmallVector<llvm::Value *> privateReductionVariables(
+ tgOp.getNumReductionVars());
+ DenseMap<Value, llvm::Value *> reductionVariableMap;
+
+ MutableArrayRef<BlockArgument> reductionArgs =
+ tgOp.getRegion().getArguments();
+
auto bodyCB = [&](InsertPointTy allocaIP, InsertPointTy codegenIP) {
builder.restoreIP(codegenIP);
+
+ if (failed(allocAndInitializeTaskReductionVars(
+ tgOp, reductionArgs, builder, moduleTranslation, allocaIP,
+ reductionDecls, privateReductionVariables, reductionVariableMap,
+ isByRef)))
+ bodyGenStatus = failure();
+ SmallVector<llvm::PHINode *> phis;
convertOmpOpRegions(tgOp.getRegion(), "omp.taskgroup.region", builder,
- moduleTranslation, bodyGenStatus);
+ moduleTranslation, bodyGenStatus, &phis);
};
InsertPointTy allocaIP = findAllocaInsertPoint(builder, moduleTranslation);
llvm::OpenMPIRBuilder::LocationDescription ompLoc(builder);
diff --git a/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir b/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir
new file mode 100644
index 00000000000000..1d4d22d5413c61
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir
@@ -0,0 +1,79 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+omp.declare_reduction @add_reduction_i32 : i32 init {
+^bb0(%arg0: i32):
+ %0 = llvm.mlir.constant(0 : i32) : i32
+ omp.yield(%0 : i32)
+} combiner {
+^bb0(%arg0: i32, %arg1: i32):
+ %0 = llvm.add %arg0, %arg1 : i32
+ omp.yield(%0 : i32)
+}
+llvm.func @_QPtest_task_reduciton() {
+ %0 = llvm.mlir.constant(1 : i64) : i64
+ %1 = llvm.alloca %0 x i32 {bindc_name = "x"} : (i64) -> !llvm.ptr
+ omp.taskgroup task_reduction(@add_reduction_i32 %1 -> %arg0 : !llvm.ptr) {
+ %2 = llvm.load %1 : !llvm.ptr -> i32
+ %3 = llvm.mlir.constant(1 : i32) : i32
+ %4 = llvm.add %2, %3 : i32
+ llvm.store %4, %1 : i32, !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+}
+
+//CHECK-LABEL: define void @_QPtest_task_reduciton() {
+//CHECK: %[[VAL1:.*]] = alloca i32, i64 1, align 4
+//CHECK: %[[RED_ARRY:.*]] = alloca [1 x %kmp_taskred_input_t], align 8
+//CHECK: br label %entry
+
+//CHECK: entry:
+//CHECK: %[[TID:.*]] = call i32 @__kmpc_global_thread_num(ptr @{{.*}})
+//CHECK: call void @__kmpc_taskgroup(ptr @1, i32 %[[TID]])
+//CHECK: %[[RED_ELEMENT:.*]] = getelementptr [1 x %kmp_taskred_input_t], ptr %[[RED_ARRY]], i32 0, i32 0
+//CHECK: %[[RED_SHARED:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 0
+//CHECK: store ptr %[[VAL1]], ptr %[[RED_SHARED]], align 8
+//CHECK: %[[RED_ORIG:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 1
+//CHECK: store ptr %[[VAL1]], ptr %[[RED_ORIG]], align 8
+//CHECK: %[[RED_SIZE:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 2
+//CHECK: store i64 4, ptr %[[RED_SIZE]], align 4
+//CHECK: %[[RED_INIT:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 3
+//CHECK: store ptr @red_init, ptr %[[RED_INIT]], align 8
+//CHECK: %[[RED_FINI:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 4
+//CHECK: store ptr null, ptr %[[RED_FINI]], align 8
+//CHECK: %[[RED_COMB:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 5
+//CHECK: store ptr @red_comb, ptr %[[RED_COMB]], align 8
+//CHECK: %[[FLAGS:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 6
+//CHECK: store i64 0, ptr %[[FLAGS]], align 4
+//CHECK: %[[TID1:.*]] = call i32 @__kmpc_global_thread_num(ptr @{{.*}})
+//CHECK: %2 = call ptr @__kmpc_taskred_init(i32 %[[TID1]], i32 1, ptr %[[RED_ARRY]])
+//CHECK: br label %omp.taskgroup.region
+
+//CHECK: omp.taskgroup.region:
+//CHECK: %[[VAL3:.*]] = load i32, ptr %[[VAL1]], align 4
+//CHECK: %4 = add i32 %[[VAL3]], 1
+//CHECK: store i32 %4, ptr %[[VAL1]], align 4
+//CHECK: br label %omp.region.cont
+
+//CHECK: omp.region.cont:
+//CHECK: br label %taskgroup.exit
+
+//CHECK: taskgroup.exit:
+//CHECK: call void @__kmpc_end_taskgroup(ptr @{{.+}}, i32 %[[TID]])
+//CHECK: ret void
+//CHECK: }
+
+//CHECK-LABEL: define ptr @red_init(ptr noalias %0, ptr noalias %1) #2 {
+//CHECK: entry:
+//CHECK: store i32 0, ptr %0, align 4
+//CHECK: ret ptr %0
+//CHECK: }
+
+//CHECK-LABEL: define ptr @red_comb(ptr %0, ptr %1) #2 {
+//CHECK: entry:
+//CHECK: %[[LD0:.*]] = load i32, ptr %0, align 4
+//CHECK: %[[LD1:.*]] = load i32, ptr %1, align 4
+//CHECK: %[[RES:.*]] = add i32 %[[LD0]], %[[LD1]]
+//CHECK: store i32 %[[RES]], ptr %0, align 4
+//CHECK: ret ptr %0
+//CHECK: }
|
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@llvm/pr-subscribers-flang-openmp Author: None (harishch4) ChangesThis patch lowers the task_reduction clause operation to LLVM IR, similar to how Clang handles it. It generates task reduction functions (red_init, red_comb, red_fini, etc.) and maps them to an internal structure, kmp_taskred_input_t, before invoking the runtime call __kmpc_taskred_init. Currently, it supports task reduction variables passed by value (VAL). A TODO has been added for handling variables passed by reference. Full diff: https://github.com/llvm/llvm-project/pull/111788.diff 3 Files Affected:
diff --git a/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td b/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
index 886554f66afffc..4a30c35549903b 100644
--- a/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
+++ b/mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td
@@ -1128,6 +1128,13 @@ class OpenMP_TaskReductionClauseSkip<
unsigned numTaskReductionBlockArgs() {
return getTaskReductionVars().size();
}
+
+ /// Returns the number of reduction variables.
+ unsigned getNumReductionVars() { return getReductionVars().size(); }
+
+ auto getReductionSyms() {
+ return getTaskReductionSyms();
+ }
}];
let description = [{
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 19d80fbbd699b0..d1162d6afcc4bb 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -1112,9 +1112,8 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
LogicalResult bodyGenStatus = success();
if (taskOp.getUntiedAttr() || taskOp.getMergeableAttr() ||
- taskOp.getInReductionSyms() || taskOp.getPriority() ||
- !taskOp.getAllocateVars().empty() || !taskOp.getPrivateVars().empty() ||
- taskOp.getPrivateSyms()) {
+ taskOp.getPriority() || !taskOp.getAllocateVars().empty() ||
+ !taskOp.getPrivateVars().empty() || taskOp.getPrivateSyms()) {
return taskOp.emitError("unhandled clauses for translation to LLVM IR");
}
auto bodyCB = [&](InsertPointTy allocaIP, InsertPointTy codegenIP) {
@@ -1142,19 +1141,238 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
return bodyGenStatus;
}
+template <typename OP>
+llvm::Value *createTaskReductionFunction(
+ llvm::IRBuilderBase &builder, const std::string &name, llvm::Type *redTy,
+ LLVM::ModuleTranslation &moduleTranslation,
+ SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls, Region ®ion,
+ OP &op, unsigned Cnt, llvm::ArrayRef<bool> &isByRef,
+ SmallVectorImpl<llvm::Value *> &privateReductionVariables,
+ DenseMap<Value, llvm::Value *> &reductionVariableMap) {
+ llvm::LLVMContext &Context = builder.getContext();
+ llvm::Type *OpaquePtrTy = llvm::PointerType::get(Context, 0);
+ // TODO: by-ref reduction variables are yet to be handled.
+ if (region.empty() || isByRef[Cnt]) {
+ return llvm::Constant::getNullValue(OpaquePtrTy);
+ }
+ llvm::FunctionType *funcType =
+ llvm::FunctionType::get(OpaquePtrTy, {OpaquePtrTy, OpaquePtrTy}, false);
+ llvm::Function *function =
+ llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, name,
+ builder.GetInsertBlock()->getModule());
+ function->setDoesNotRecurse();
+ llvm::BasicBlock *entry =
+ llvm::BasicBlock::Create(Context, "entry", function);
+ llvm::IRBuilder<> bbBuilder(entry);
+
+ llvm::Value *arg0 = function->getArg(0);
+ llvm::Value *arg1 = function->getArg(1);
+
+ if (name == "red_init") {
+ function->addParamAttr(0, llvm::Attribute::NoAlias);
+ function->addParamAttr(1, llvm::Attribute::NoAlias);
+ mapInitializationArgs(op, moduleTranslation, reductionDecls,
+ reductionVariableMap, Cnt);
+ } else if (name == "red_comb") {
+ llvm::Value *arg0L = bbBuilder.CreateLoad(redTy, arg0);
+ llvm::Value *arg1L = bbBuilder.CreateLoad(redTy, arg1);
+ moduleTranslation.mapValue(region.front().getArgument(0), arg0L);
+ moduleTranslation.mapValue(region.front().getArgument(1), arg1L);
+ }
+
+ SmallVector<llvm::Value *, 1> phis;
+ if (failed(inlineConvertOmpRegions(region, "", bbBuilder, moduleTranslation,
+ &phis)))
+ return nullptr;
+ assert(
+ phis.size() == 1 &&
+ "expected one value to be yielded from the reduction declaration region");
+
+ bbBuilder.CreateStore(phis[0], arg0);
+ bbBuilder.CreateRet(arg0); // Return from the function
+ return function;
+}
+
+void emitTaskRedInitCall(
+ llvm::IRBuilderBase &builder, LLVM::ModuleTranslation &moduleTranslation,
+ const llvm::OpenMPIRBuilder::LocationDescription &ompLoc, int arraySize,
+ llvm::Value *ArrayAlloca) {
+
+ llvm::LLVMContext &Context = builder.getContext();
+ uint32_t SrcLocStrSize;
+ llvm::Constant *SrcLocStr =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateSrcLocStr(ompLoc,
+ SrcLocStrSize);
+ llvm::Value *Ident = moduleTranslation.getOpenMPBuilder()->getOrCreateIdent(
+ SrcLocStr, SrcLocStrSize);
+ llvm::Value *ThreadID =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateThreadID(Ident);
+ llvm::Constant *ConstInt =
+ llvm::ConstantInt::get(llvm::Type::getInt32Ty(Context), arraySize);
+
+ llvm::Function *TaskRedInitFn =
+ moduleTranslation.getOpenMPBuilder()->getOrCreateRuntimeFunctionPtr(
+ llvm::omp::OMPRTL___kmpc_taskred_init);
+ builder.CreateCall(TaskRedInitFn, {ThreadID, ConstInt, ArrayAlloca});
+}
+
+template <typename OP>
+static LogicalResult allocAndInitializeTaskReductionVars(
+ OP op, ArrayRef<BlockArgument> reductionArgs, llvm::IRBuilderBase &builder,
+ LLVM::ModuleTranslation &moduleTranslation,
+ llvm::OpenMPIRBuilder::InsertPointTy &allocaIP,
+ SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls,
+ SmallVectorImpl<llvm::Value *> &privateReductionVariables,
+ DenseMap<Value, llvm::Value *> &reductionVariableMap,
+ llvm::ArrayRef<bool> isByRef) {
+
+ if (op.getNumReductionVars() == 0)
+ return success();
+
+ llvm::OpenMPIRBuilder::LocationDescription ompLoc(builder);
+ llvm::LLVMContext &Context = builder.getContext();
+ SmallVector<DeferredStore> deferredStores;
+
+ // Save the current insertion point
+ auto oldIP = builder.saveIP();
+
+ // Set insertion point after the allocations
+ builder.SetInsertPoint(allocaIP.getBlock()->getTerminator());
+
+ // Define the kmp_taskred_input_t structure
+ llvm::StructType *kmp_taskred_input_t =
+ llvm::StructType::create(Context, "kmp_taskred_input_t");
+ llvm::Type *OpaquePtrTy = llvm::PointerType::get(Context, 0); // void*
+ llvm::Type *SizeTy = builder.getInt64Ty(); // size_t (assumed to be i64)
+ llvm::Type *FlagsTy = llvm::Type::getInt32Ty(Context); // flags (i32)
+
+ // Structure members
+ std::vector<llvm::Type *> structMembers = {
+ OpaquePtrTy, // reduce_shar (void*)
+ OpaquePtrTy, // reduce_orig (void*)
+ SizeTy, // reduce_size (size_t)
+ OpaquePtrTy, // reduce_init (void*)
+ OpaquePtrTy, // reduce_fini (void*)
+ OpaquePtrTy, // reduce_comb (void*)
+ FlagsTy // flags (i32)
+ };
+
+ kmp_taskred_input_t->setBody(structMembers);
+ int arraySize = op.getNumReductionVars();
+ llvm::ArrayType *ArrayTy =
+ llvm::ArrayType::get(kmp_taskred_input_t, arraySize);
+
+ // Allocate the array for kmp_taskred_input_t
+ llvm::AllocaInst *ArrayAlloca =
+ builder.CreateAlloca(ArrayTy, nullptr, "kmp_taskred_array");
+
+ // Restore the insertion point
+ builder.restoreIP(oldIP);
+ llvm::DataLayout DL = builder.GetInsertBlock()->getModule()->getDataLayout();
+
+ for (int Cnt = 0; Cnt < arraySize; ++Cnt) {
+ llvm::Value *shared =
+ moduleTranslation.lookupValue(op.getReductionVars()[Cnt]);
+ // Create a GEP to access the reduction element
+ llvm::Value *StructPtr = builder.CreateGEP(
+ ArrayTy, ArrayAlloca, {builder.getInt32(0), builder.getInt32(Cnt)},
+ "red_element");
+
+ llvm::Value *FieldPtrReduceShar = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 0, "reduce_shar");
+ builder.CreateStore(shared, FieldPtrReduceShar);
+
+ llvm::Value *FieldPtrReduceOrig = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 1, "reduce_orig");
+ builder.CreateStore(shared, FieldPtrReduceOrig);
+
+ // Store size of the reduction variable
+ llvm::Value *FieldPtrReduceSize = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 2, "reduce_size");
+ llvm::Type *redTy;
+ if (auto *alloca = dyn_cast<llvm::AllocaInst>(shared)) {
+ redTy = alloca->getAllocatedType();
+ uint64_t sizeInBytes = DL.getTypeAllocSize(redTy);
+
+ llvm::ConstantInt *sizeConst =
+ llvm::ConstantInt::get(llvm::Type::getInt64Ty(Context), sizeInBytes);
+ builder.CreateStore(sizeConst, FieldPtrReduceSize);
+ } else {
+ llvm_unreachable("Non alloca instruction found.");
+ }
+
+ // Initialize reduction variable
+ llvm::Value *FieldPtrReduceInit = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 3, "reduce_init");
+ llvm::Value *initFunction = createTaskReductionFunction(
+ builder, "red_init", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getInitializerRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(initFunction, FieldPtrReduceInit);
+
+ // Create finish and combine functions
+ llvm::Value *FieldPtrReduceFini = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 4, "reduce_fini");
+ llvm::Value *finiFunction = createTaskReductionFunction(
+ builder, "red_fini", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getCleanupRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(finiFunction, FieldPtrReduceFini);
+
+ llvm::Value *FieldPtrReduceComb = builder.CreateStructGEP(
+ kmp_taskred_input_t, StructPtr, 5, "reduce_comb");
+ llvm::Value *combFunction = createTaskReductionFunction(
+ builder, "red_comb", redTy, moduleTranslation, reductionDecls,
+ reductionDecls[Cnt].getReductionRegion(), op, Cnt, isByRef,
+ privateReductionVariables, reductionVariableMap);
+ builder.CreateStore(combFunction, FieldPtrReduceComb);
+
+ llvm::Value *FieldPtrFlags =
+ builder.CreateStructGEP(kmp_taskred_input_t, StructPtr, 6, "flags");
+ llvm::ConstantInt *flagVal =
+ llvm::ConstantInt::get(llvm::Type::getInt64Ty(Context), 0);
+ builder.CreateStore(flagVal, FieldPtrFlags);
+ }
+
+ // Emit the runtime call
+ emitTaskRedInitCall(builder, moduleTranslation, ompLoc, arraySize,
+ ArrayAlloca);
+ return success();
+}
+
/// Converts an OpenMP taskgroup construct into LLVM IR using OpenMPIRBuilder.
static LogicalResult
convertOmpTaskgroupOp(omp::TaskgroupOp tgOp, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &moduleTranslation) {
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
LogicalResult bodyGenStatus = success();
- if (!tgOp.getTaskReductionVars().empty() || !tgOp.getAllocateVars().empty()) {
+ if (!tgOp.getAllocateVars().empty()) {
return tgOp.emitError("unhandled clauses for translation to LLVM IR");
}
+
+ llvm::ArrayRef<bool> isByRef = getIsByRef(tgOp.getTaskReductionByref());
+ assert(isByRef.size() == tgOp.getNumReductionVars());
+
+ SmallVector<omp::DeclareReductionOp> reductionDecls;
+ collectReductionDecls(tgOp, reductionDecls);
+ SmallVector<llvm::Value *> privateReductionVariables(
+ tgOp.getNumReductionVars());
+ DenseMap<Value, llvm::Value *> reductionVariableMap;
+
+ MutableArrayRef<BlockArgument> reductionArgs =
+ tgOp.getRegion().getArguments();
+
auto bodyCB = [&](InsertPointTy allocaIP, InsertPointTy codegenIP) {
builder.restoreIP(codegenIP);
+
+ if (failed(allocAndInitializeTaskReductionVars(
+ tgOp, reductionArgs, builder, moduleTranslation, allocaIP,
+ reductionDecls, privateReductionVariables, reductionVariableMap,
+ isByRef)))
+ bodyGenStatus = failure();
+ SmallVector<llvm::PHINode *> phis;
convertOmpOpRegions(tgOp.getRegion(), "omp.taskgroup.region", builder,
- moduleTranslation, bodyGenStatus);
+ moduleTranslation, bodyGenStatus, &phis);
};
InsertPointTy allocaIP = findAllocaInsertPoint(builder, moduleTranslation);
llvm::OpenMPIRBuilder::LocationDescription ompLoc(builder);
diff --git a/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir b/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir
new file mode 100644
index 00000000000000..1d4d22d5413c61
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-task-reduction.mlir
@@ -0,0 +1,79 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+omp.declare_reduction @add_reduction_i32 : i32 init {
+^bb0(%arg0: i32):
+ %0 = llvm.mlir.constant(0 : i32) : i32
+ omp.yield(%0 : i32)
+} combiner {
+^bb0(%arg0: i32, %arg1: i32):
+ %0 = llvm.add %arg0, %arg1 : i32
+ omp.yield(%0 : i32)
+}
+llvm.func @_QPtest_task_reduciton() {
+ %0 = llvm.mlir.constant(1 : i64) : i64
+ %1 = llvm.alloca %0 x i32 {bindc_name = "x"} : (i64) -> !llvm.ptr
+ omp.taskgroup task_reduction(@add_reduction_i32 %1 -> %arg0 : !llvm.ptr) {
+ %2 = llvm.load %1 : !llvm.ptr -> i32
+ %3 = llvm.mlir.constant(1 : i32) : i32
+ %4 = llvm.add %2, %3 : i32
+ llvm.store %4, %1 : i32, !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+}
+
+//CHECK-LABEL: define void @_QPtest_task_reduciton() {
+//CHECK: %[[VAL1:.*]] = alloca i32, i64 1, align 4
+//CHECK: %[[RED_ARRY:.*]] = alloca [1 x %kmp_taskred_input_t], align 8
+//CHECK: br label %entry
+
+//CHECK: entry:
+//CHECK: %[[TID:.*]] = call i32 @__kmpc_global_thread_num(ptr @{{.*}})
+//CHECK: call void @__kmpc_taskgroup(ptr @1, i32 %[[TID]])
+//CHECK: %[[RED_ELEMENT:.*]] = getelementptr [1 x %kmp_taskred_input_t], ptr %[[RED_ARRY]], i32 0, i32 0
+//CHECK: %[[RED_SHARED:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 0
+//CHECK: store ptr %[[VAL1]], ptr %[[RED_SHARED]], align 8
+//CHECK: %[[RED_ORIG:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 1
+//CHECK: store ptr %[[VAL1]], ptr %[[RED_ORIG]], align 8
+//CHECK: %[[RED_SIZE:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 2
+//CHECK: store i64 4, ptr %[[RED_SIZE]], align 4
+//CHECK: %[[RED_INIT:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 3
+//CHECK: store ptr @red_init, ptr %[[RED_INIT]], align 8
+//CHECK: %[[RED_FINI:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 4
+//CHECK: store ptr null, ptr %[[RED_FINI]], align 8
+//CHECK: %[[RED_COMB:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 5
+//CHECK: store ptr @red_comb, ptr %[[RED_COMB]], align 8
+//CHECK: %[[FLAGS:.*]] = getelementptr inbounds nuw %kmp_taskred_input_t, ptr %[[RED_ELEMENT]], i32 0, i32 6
+//CHECK: store i64 0, ptr %[[FLAGS]], align 4
+//CHECK: %[[TID1:.*]] = call i32 @__kmpc_global_thread_num(ptr @{{.*}})
+//CHECK: %2 = call ptr @__kmpc_taskred_init(i32 %[[TID1]], i32 1, ptr %[[RED_ARRY]])
+//CHECK: br label %omp.taskgroup.region
+
+//CHECK: omp.taskgroup.region:
+//CHECK: %[[VAL3:.*]] = load i32, ptr %[[VAL1]], align 4
+//CHECK: %4 = add i32 %[[VAL3]], 1
+//CHECK: store i32 %4, ptr %[[VAL1]], align 4
+//CHECK: br label %omp.region.cont
+
+//CHECK: omp.region.cont:
+//CHECK: br label %taskgroup.exit
+
+//CHECK: taskgroup.exit:
+//CHECK: call void @__kmpc_end_taskgroup(ptr @{{.+}}, i32 %[[TID]])
+//CHECK: ret void
+//CHECK: }
+
+//CHECK-LABEL: define ptr @red_init(ptr noalias %0, ptr noalias %1) #2 {
+//CHECK: entry:
+//CHECK: store i32 0, ptr %0, align 4
+//CHECK: ret ptr %0
+//CHECK: }
+
+//CHECK-LABEL: define ptr @red_comb(ptr %0, ptr %1) #2 {
+//CHECK: entry:
+//CHECK: %[[LD0:.*]] = load i32, ptr %0, align 4
+//CHECK: %[[LD1:.*]] = load i32, ptr %1, align 4
+//CHECK: %[[RES:.*]] = add i32 %[[LD0]], %[[LD1]]
+//CHECK: store i32 %[[RES]], ptr %0, align 4
+//CHECK: ret ptr %0
+//CHECK: }
|
Dinistro
reviewed
Oct 10, 2024
| @@ -1142,19 +1141,238 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder, | |||
| return bodyGenStatus; | |||
| } | |||
|
|
|||
| template <typename OP> | |||
| llvm::Value *createTaskReductionFunction( | |||
There was a problem hiding this comment.
Nit: This should be static and requires a comment.
Comment on lines
+1155
to
+1157
| if (region.empty() || isByRef[Cnt]) { | ||
| return llvm::Constant::getNullValue(OpaquePtrTy); | ||
| } |
There was a problem hiding this comment.
Suggested change
| if (region.empty() || isByRef[Cnt]) { | |
| return llvm::Constant::getNullValue(OpaquePtrTy); | |
| } | |
| if (region.empty() || isByRef[Cnt]) | |
| return llvm::Constant::getNullValue(OpaquePtrTy); |
Comment on lines
+1158
to
+1159
| llvm::FunctionType *funcType = | ||
| llvm::FunctionType::get(OpaquePtrTy, {OpaquePtrTy, OpaquePtrTy}, false); |
There was a problem hiding this comment.
Suggested change
| llvm::FunctionType *funcType = | |
| llvm::FunctionType::get(OpaquePtrTy, {OpaquePtrTy, OpaquePtrTy}, false); | |
| auto *funcType = | |
| llvm::FunctionType::get(OpaquePtrTy, {OpaquePtrTy, OpaquePtrTy}, false); |
Nit: We use auto when the type is explicitly given on the RHS already.
| @@ -1142,19 +1141,238 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder, | |||
| return bodyGenStatus; | |||
| } | |||
|
|
|||
| template <typename OP> | |||
| llvm::Value *createTaskReductionFunction( | |||
| llvm::IRBuilderBase &builder, const std::string &name, llvm::Type *redTy, | |||
There was a problem hiding this comment.
Suggested change
| llvm::IRBuilderBase &builder, const std::string &name, llvm::Type *redTy, | |
| llvm::IRBuilderBase &builder, StringRef name, llvm::Type *redTy, |
| llvm::Value *arg0 = function->getArg(0); | ||
| llvm::Value *arg1 = function->getArg(1); | ||
|
|
||
| if (name == "red_init") { |
There was a problem hiding this comment.
Nit: Please avoid magic strings. Introduce global constexpr StringLiterals for such things.
| DenseMap<Value, llvm::Value *> &reductionVariableMap) { | ||
| llvm::LLVMContext &Context = builder.getContext(); | ||
| llvm::Type *OpaquePtrTy = llvm::PointerType::get(Context, 0); | ||
| // TODO: by-ref reduction variables are yet to be handled. |
There was a problem hiding this comment.
Isn't it better to crash/assert than silently swallowing cases like this?
| return function; | ||
| } | ||
|
|
||
| void emitTaskRedInitCall( |
There was a problem hiding this comment.
Nit: As above, this should be static and requires a comment.
| llvm::IRBuilderBase &builder, LLVM::ModuleTranslation &moduleTranslation, | ||
| const llvm::OpenMPIRBuilder::LocationDescription &ompLoc, int arraySize, | ||
| llvm::Value *ArrayAlloca) { | ||
|
|
| void emitTaskRedInitCall( | ||
| llvm::IRBuilderBase &builder, LLVM::ModuleTranslation &moduleTranslation, | ||
| const llvm::OpenMPIRBuilder::LocationDescription &ompLoc, int arraySize, | ||
| llvm::Value *ArrayAlloca) { |
There was a problem hiding this comment.
Suggested change
| llvm::Value *ArrayAlloca) { | |
| llvm::Value *arrayAlloca) { |
Ultra nit: Uppercase beginning variables violate the MLIR style guide.
| //CHECK: %[[RED_ARRY:.*]] = alloca [1 x %kmp_taskred_input_t], align 8 | ||
| //CHECK: br label %entry | ||
|
|
||
| //CHECK: entry: |
There was a problem hiding this comment.
That's a bit odd. Normally, "entry" is really the first block of a function.
tblah
reviewed
Oct 10, 2024
| } | ||
|
|
||
| SmallVector<llvm::Value *, 1> phis; | ||
| if (failed(inlineConvertOmpRegions(region, "", bbBuilder, moduleTranslation, |
There was a problem hiding this comment.
nit: Adding a block name makes this a lot easier to debug if the region is translated into multiple basic blocks.
Comment on lines
+1213
to
+1216
| llvm::Function *TaskRedInitFn = | ||
| moduleTranslation.getOpenMPBuilder()->getOrCreateRuntimeFunctionPtr( | ||
| llvm::omp::OMPRTL___kmpc_taskred_init); | ||
| builder.CreateCall(TaskRedInitFn, {ThreadID, ConstInt, ArrayAlloca}); |
There was a problem hiding this comment.
For non-task reductions these sorts of function calls are generated by OpenMPIRBuilder so that we can share code with clang.
Are the clang people happy with us having diverging implementations here? If so I don't mind.
| reductionDecls, privateReductionVariables, reductionVariableMap, | ||
| isByRef))) | ||
| bodyGenStatus = failure(); | ||
| SmallVector<llvm::PHINode *> phis; |
There was a problem hiding this comment.
The phis seem unused here. Can the task reduction region omp.yield any values or is omp.terminator the only terminator?
| %0 = llvm.mlir.constant(1 : i64) : i64 | ||
| %1 = llvm.alloca %0 x i32 {bindc_name = "x"} : (i64) -> !llvm.ptr | ||
| omp.taskgroup task_reduction(@add_reduction_i32 %1 -> %arg0 : !llvm.ptr) { | ||
| %2 = llvm.load %1 : !llvm.ptr -> i32 |
There was a problem hiding this comment.
I know this is only test code but shouldn't this be using the block argument?
| //CHECK: ret void | ||
| //CHECK: } | ||
|
|
||
| //CHECK-LABEL: define ptr @red_init(ptr noalias %0, ptr noalias %1) #2 { |
There was a problem hiding this comment.
This name could collide with symbols in the program. clang uses .red_init. (and likewise .red_comb.).
|
Are multiple blocks allowed
Please could you add test(s) showing that these work correctly or asserts if these are TODO (I think you don't need multi block reduction regions until you support allocatable arrays). |
|
@tblah Did we switch all flang reductions to byref? If so, is there value in having task reductions by value? |
No. We still support by value reductions where we can because there were concerns that the indirection involved in byref would regress performance in those cases |
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This patch lowers the task_reduction clause operation to LLVM IR, similar to how Clang handles it. It generates task reduction functions (red_init, red_comb, red_fini, etc.) and maps them to an internal structure, kmp_taskred_input_t, before invoking the runtime call __kmpc_taskred_init.
Currently, it supports task reduction variables passed by value (VAL). A TODO has been added for handling variables passed by reference.