[Mlir-commits] [mlir] [MLIR][OpenMP] Support basic materialization for `omp.private` ops (PR #81715)
Kareem Ergawy
llvmlistbot at llvm.org
Tue Feb 27 09:12:18 PST 2024
https://github.com/ergawy updated https://github.com/llvm/llvm-project/pull/81715
>From a043ecee87ec08d3bace37ae0e0a6c4ffae8ced1 Mon Sep 17 00:00:00 2001
From: ergawy <kareem.ergawy at amd.com>
Date: Tue, 13 Feb 2024 04:46:50 -0600
Subject: [PATCH 1/2] [MLIR][OpenMP] Support basic materialization for
`omp.private` ops
Adds basic support for materializing delayed privatization. So far, the
restrictions on the implementation are:
- Only `private` clauses are supported (`firstprivate` support will be
added in a later PR).
- Only single-block `omp.private -> alloc` regions are supported
(multi-block ones will be supported in a later PR).
---
mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp | 5 +-
.../OpenMP/OpenMPToLLVMIRTranslation.cpp | 201 ++++++++++++++----
mlir/test/Target/LLVMIR/openmp-private.mlir | 142 +++++++++++++
3 files changed, 304 insertions(+), 44 deletions(-)
create mode 100644 mlir/test/Target/LLVMIR/openmp-private.mlir
diff --git a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
index c2b471ab96183f..8a6980e2c6a2d9 100644
--- a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
+++ b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
@@ -1957,7 +1957,10 @@ LogicalResult PrivateClauseOp::verify() {
Type symType = getType();
auto verifyTerminator = [&](Operation *terminator) -> LogicalResult {
- if (!terminator->hasSuccessors() && !llvm::isa<YieldOp>(terminator))
+ if (!terminator->getBlock()->getSuccessors().empty())
+ return success();
+
+ if (!llvm::isa<YieldOp>(terminator))
return mlir::emitError(terminator->getLoc())
<< "expected exit block terminator to be an `omp.yield` op.";
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 6e53d801a0d2f0..0c390f68bb6890 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -396,9 +396,9 @@ collectReductionDecls(T loop,
/// Translates the blocks contained in the given region and appends them to at
/// the current insertion point of `builder`. The operations of the entry block
-/// are appended to the current insertion block, which is not expected to have a
-/// terminator. If set, `continuationBlockArgs` is populated with translated
-/// values that correspond to the values omp.yield'ed from the region.
+/// are appended to the current insertion block. If set, `continuationBlockArgs`
+/// is populated with translated values that correspond to the values
+/// omp.yield'ed from the region.
static LogicalResult inlineConvertOmpRegions(
Region ®ion, StringRef blockName, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &moduleTranslation,
@@ -409,7 +409,14 @@ static LogicalResult inlineConvertOmpRegions(
// Special case for single-block regions that don't create additional blocks:
// insert operations without creating additional blocks.
if (llvm::hasSingleElement(region)) {
+ llvm::Instruction *potentialTerminator =
+ builder.GetInsertBlock()->empty() ? nullptr
+ : &builder.GetInsertBlock()->back();
+
+ if (potentialTerminator && potentialTerminator->isTerminator())
+ potentialTerminator->removeFromParent();
moduleTranslation.mapBlock(®ion.front(), builder.GetInsertBlock());
+
if (failed(moduleTranslation.convertBlock(
region.front(), /*ignoreArguments=*/true, builder)))
return failure();
@@ -423,6 +430,10 @@ static LogicalResult inlineConvertOmpRegions(
// Drop the mapping that is no longer necessary so that the same region can
// be processed multiple times.
moduleTranslation.forgetMapping(region);
+
+ if (potentialTerminator && potentialTerminator->isTerminator())
+ potentialTerminator->insertAfter(&builder.GetInsertBlock()->back());
+
return success();
}
@@ -1000,11 +1011,41 @@ convertOmpWsLoop(Operation &opInst, llvm::IRBuilderBase &builder,
return success();
}
+/// Replace the region arguments of the parallel op (which correspond to private
+/// variables) with the actual private variables they correspond to. This
+/// prepares the parallel op so that it matches what is expected by the
+/// OMPIRBuilder. Instead of editing the original op in-place, this function
+/// does the required changes to a cloned version which should then be erased by
+/// the caller.
+static omp::ParallelOp
+prepareOmpParallelForPrivatization(omp::ParallelOp opInst) {
+ Region ®ion = opInst.getRegion();
+ auto privateVars = opInst.getPrivateVars();
+
+ auto privateVarsIt = privateVars.begin();
+ // Reduction precede private arguments, so skip them first.
+ unsigned privateArgBeginIdx = opInst.getNumReductionVars();
+ unsigned privateArgEndIdx = privateArgBeginIdx + privateVars.size();
+
+ mlir::IRMapping mapping;
+ for (size_t argIdx = privateArgBeginIdx; argIdx < privateArgEndIdx;
+ ++argIdx, ++privateVarsIt)
+ mapping.map(region.getArgument(argIdx), *privateVarsIt);
+
+ mlir::OpBuilder cloneBuilder(opInst);
+ omp::ParallelOp opInstClone =
+ llvm::cast<omp::ParallelOp>(cloneBuilder.clone(*opInst, mapping));
+
+ return opInstClone;
+}
+
/// Converts the OpenMP parallel operation to LLVM IR.
static LogicalResult
convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &moduleTranslation) {
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
+ omp::ParallelOp opInstClone = prepareOmpParallelForPrivatization(opInst);
+
// TODO: support error propagation in OpenMPIRBuilder and use it instead of
// relying on captured variables.
LogicalResult bodyGenStatus = success();
@@ -1013,12 +1054,12 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
auto bodyGenCB = [&](InsertPointTy allocaIP, InsertPointTy codeGenIP) {
// Collect reduction declarations
SmallVector<omp::ReductionDeclareOp> reductionDecls;
- collectReductionDecls(opInst, reductionDecls);
+ collectReductionDecls(opInstClone, reductionDecls);
// Allocate reduction vars
SmallVector<llvm::Value *> privateReductionVariables;
DenseMap<Value, llvm::Value *> reductionVariableMap;
- allocReductionVars(opInst, builder, moduleTranslation, allocaIP,
+ allocReductionVars(opInstClone, builder, moduleTranslation, allocaIP,
reductionDecls, privateReductionVariables,
reductionVariableMap);
@@ -1030,7 +1071,7 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// Initialize reduction vars
builder.restoreIP(allocaIP);
- for (unsigned i = 0; i < opInst.getNumReductionVars(); ++i) {
+ for (unsigned i = 0; i < opInstClone.getNumReductionVars(); ++i) {
SmallVector<llvm::Value *> phis;
if (failed(inlineConvertOmpRegions(
reductionDecls[i].getInitializerRegion(), "omp.reduction.neutral",
@@ -1051,18 +1092,19 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// ParallelOp has only one region associated with it.
builder.restoreIP(codeGenIP);
auto regionBlock =
- convertOmpOpRegions(opInst.getRegion(), "omp.par.region", builder,
+ convertOmpOpRegions(opInstClone.getRegion(), "omp.par.region", builder,
moduleTranslation, bodyGenStatus);
// Process the reductions if required.
- if (opInst.getNumReductionVars() > 0) {
+ if (opInstClone.getNumReductionVars() > 0) {
// Collect reduction info
SmallVector<OwningReductionGen> owningReductionGens;
SmallVector<OwningAtomicReductionGen> owningAtomicReductionGens;
SmallVector<llvm::OpenMPIRBuilder::ReductionInfo> reductionInfos;
- collectReductionInfo(opInst, builder, moduleTranslation, reductionDecls,
- owningReductionGens, owningAtomicReductionGens,
- privateReductionVariables, reductionInfos);
+ collectReductionInfo(opInstClone, builder, moduleTranslation,
+ reductionDecls, owningReductionGens,
+ owningAtomicReductionGens, privateReductionVariables,
+ reductionInfos);
// Move to region cont block
builder.SetInsertPoint(regionBlock->getTerminator());
@@ -1075,7 +1117,8 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
ompBuilder->createReductions(builder.saveIP(), allocaIP,
reductionInfos, false);
if (!contInsertPoint.getBlock()) {
- bodyGenStatus = opInst->emitOpError() << "failed to convert reductions";
+ bodyGenStatus = opInstClone->emitOpError()
+ << "failed to convert reductions";
return;
}
@@ -1086,12 +1129,82 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// TODO: Perform appropriate actions according to the data-sharing
// attribute (shared, private, firstprivate, ...) of variables.
- // Currently defaults to shared.
+ // Currently shared and private are supported.
auto privCB = [&](InsertPointTy allocaIP, InsertPointTy codeGenIP,
llvm::Value &, llvm::Value &vPtr,
llvm::Value *&replacementValue) -> InsertPointTy {
replacementValue = &vPtr;
+ // If this is a private value, this lambda will return the corresponding
+ // mlir value and its `PrivateClauseOp`. Otherwise, empty values are
+ // returned.
+ auto [privVar, privatizerClone] =
+ [&]() -> std::pair<mlir::Value, omp::PrivateClauseOp> {
+ if (!opInstClone.getPrivateVars().empty()) {
+ auto privVars = opInstClone.getPrivateVars();
+ auto privatizers = opInstClone.getPrivatizers();
+
+ for (auto [privVar, privatizerAttr] :
+ llvm::zip_equal(privVars, *privatizers)) {
+ // Find the MLIR private variable corresponding to the LLVM value
+ // being privatized.
+ llvm::Value *llvmPrivVar = moduleTranslation.lookupValue(privVar);
+ if (llvmPrivVar != &vPtr)
+ continue;
+
+ SymbolRefAttr privSym = llvm::cast<SymbolRefAttr>(privatizerAttr);
+ omp::PrivateClauseOp privatizer =
+ SymbolTable::lookupNearestSymbolFrom<omp::PrivateClauseOp>(
+ opInstClone, privSym);
+
+ // Clone the privatizer in case it is used by more than one parallel
+ // region. The privatizer is processed in-place (see below) before it
+ // gets inlined in the parallel region and therefore processing the
+ // original op is dangerous.
+ return {privVar, privatizer.clone()};
+ }
+ }
+
+ return {mlir::Value(), omp::PrivateClauseOp()};
+ }();
+
+ if (privVar) {
+ if (privatizerClone.getDataSharingType() ==
+ omp::DataSharingClauseType::FirstPrivate) {
+ privatizerClone.emitOpError(
+ "TODO: delayed privatization is not "
+ "supported for `firstprivate` clauses yet.");
+ bodyGenStatus = failure();
+ return codeGenIP;
+ }
+
+ Region &allocRegion = privatizerClone.getAllocRegion();
+
+ // Replace the privatizer block argument with mlir value being privatized.
+ // This way, the body of the privatizer will be changed from using the
+ // region/block argument to the value being privatized.
+ auto allocRegionArg = allocRegion.getArgument(0);
+ replaceAllUsesInRegionWith(allocRegionArg, privVar, allocRegion);
+
+ auto oldIP = builder.saveIP();
+ builder.restoreIP(allocaIP);
+
+ SmallVector<llvm::Value *, 1> yieldedValues;
+ if (failed(inlineConvertOmpRegions(allocRegion, "omp.privatizer", builder,
+ moduleTranslation, &yieldedValues))) {
+ opInstClone.emitError(
+ "failed to inline `alloc` region of an `omp.private` "
+ "op in the parallel region");
+ bodyGenStatus = failure();
+ } else {
+ assert(yieldedValues.size() == 1);
+ replacementValue = yieldedValues.front();
+ }
+
+ privatizerClone.erase();
+ builder.restoreIP(oldIP);
+ }
+
return codeGenIP;
};
@@ -1100,13 +1213,13 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
auto finiCB = [&](InsertPointTy codeGenIP) {};
llvm::Value *ifCond = nullptr;
- if (auto ifExprVar = opInst.getIfExprVar())
+ if (auto ifExprVar = opInstClone.getIfExprVar())
ifCond = moduleTranslation.lookupValue(ifExprVar);
llvm::Value *numThreads = nullptr;
- if (auto numThreadsVar = opInst.getNumThreadsVar())
+ if (auto numThreadsVar = opInstClone.getNumThreadsVar())
numThreads = moduleTranslation.lookupValue(numThreadsVar);
auto pbKind = llvm::omp::OMP_PROC_BIND_default;
- if (auto bind = opInst.getProcBindVal())
+ if (auto bind = opInstClone.getProcBindVal())
pbKind = getProcBindKind(*bind);
// TODO: Is the Parallel construct cancellable?
bool isCancellable = false;
@@ -1119,6 +1232,7 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
ompBuilder->createParallel(ompLoc, allocaIP, bodyGenCB, privCB, finiCB,
ifCond, numThreads, pbKind, isCancellable));
+ opInstClone.erase();
return bodyGenStatus;
}
@@ -1635,7 +1749,7 @@ getRefPtrIfDeclareTarget(mlir::Value value,
// A small helper structure to contain data gathered
// for map lowering and coalese it into one area and
// avoiding extra computations such as searches in the
-// llvm module for lowered mapped varibles or checking
+// llvm module for lowered mapped variables or checking
// if something is declare target (and retrieving the
// value) more than neccessary.
struct MapInfoData : llvm::OpenMPIRBuilder::MapInfosTy {
@@ -2854,26 +2968,26 @@ LogicalResult OpenMPDialectLLVMIRTranslationInterface::amendOperation(
moduleTranslation);
return failure();
})
- .Case(
- "omp.requires",
- [&](Attribute attr) {
- if (auto requiresAttr = attr.dyn_cast<omp::ClauseRequiresAttr>()) {
- using Requires = omp::ClauseRequires;
- Requires flags = requiresAttr.getValue();
- llvm::OpenMPIRBuilderConfig &config =
- moduleTranslation.getOpenMPBuilder()->Config;
- config.setHasRequiresReverseOffload(
- bitEnumContainsAll(flags, Requires::reverse_offload));
- config.setHasRequiresUnifiedAddress(
- bitEnumContainsAll(flags, Requires::unified_address));
- config.setHasRequiresUnifiedSharedMemory(
- bitEnumContainsAll(flags, Requires::unified_shared_memory));
- config.setHasRequiresDynamicAllocators(
- bitEnumContainsAll(flags, Requires::dynamic_allocators));
- return success();
- }
- return failure();
- })
+ .Case("omp.requires",
+ [&](Attribute attr) {
+ if (auto requiresAttr =
+ attr.dyn_cast<omp::ClauseRequiresAttr>()) {
+ using Requires = omp::ClauseRequires;
+ Requires flags = requiresAttr.getValue();
+ llvm::OpenMPIRBuilderConfig &config =
+ moduleTranslation.getOpenMPBuilder()->Config;
+ config.setHasRequiresReverseOffload(
+ bitEnumContainsAll(flags, Requires::reverse_offload));
+ config.setHasRequiresUnifiedAddress(
+ bitEnumContainsAll(flags, Requires::unified_address));
+ config.setHasRequiresUnifiedSharedMemory(
+ bitEnumContainsAll(flags, Requires::unified_shared_memory));
+ config.setHasRequiresDynamicAllocators(
+ bitEnumContainsAll(flags, Requires::dynamic_allocators));
+ return success();
+ }
+ return failure();
+ })
.Default([](Attribute) {
// Fall through for omp attributes that do not require lowering.
return success();
@@ -2988,12 +3102,13 @@ LogicalResult OpenMPDialectLLVMIRTranslationInterface::convertOperation(
.Case([&](omp::TargetOp) {
return convertOmpTarget(*op, builder, moduleTranslation);
})
- .Case<omp::MapInfoOp, omp::DataBoundsOp>([&](auto op) {
- // No-op, should be handled by relevant owning operations e.g.
- // TargetOp, EnterDataOp, ExitDataOp, DataOp etc. and then
- // discarded
- return success();
- })
+ .Case<omp::MapInfoOp, omp::DataBoundsOp, omp::PrivateClauseOp>(
+ [&](auto op) {
+ // No-op, should be handled by relevant owning operations e.g.
+ // TargetOp, EnterDataOp, ExitDataOp, DataOp etc. and then
+ // discarded
+ return success();
+ })
.Default([&](Operation *inst) {
return inst->emitError("unsupported OpenMP operation: ")
<< inst->getName();
diff --git a/mlir/test/Target/LLVMIR/openmp-private.mlir b/mlir/test/Target/LLVMIR/openmp-private.mlir
new file mode 100644
index 00000000000000..58bda87c3b7bea
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/openmp-private.mlir
@@ -0,0 +1,142 @@
+// Test code-gen for `omp.parallel` ops with delayed privatizers (i.e. using
+// `omp.private` ops).
+
+// RUN: mlir-translate -mlir-to-llvmir -split-input-file %s | FileCheck %s
+
+llvm.func @parallel_op_1_private(%arg0: !llvm.ptr) {
+ omp.parallel private(@x.privatizer %arg0 -> %arg2 : !llvm.ptr) {
+ %0 = llvm.load %arg2 : !llvm.ptr -> f32
+ omp.terminator
+ }
+ llvm.return
+}
+
+// CHECK-LABEL: @parallel_op_1_private
+// CHECK-SAME: (ptr %[[ORIG:.*]]) {
+// CHECK: %[[OMP_PAR_ARG:.*]] = alloca { ptr }, align 8
+// CHECK: %[[ORIG_GEP:.*]] = getelementptr { ptr }, ptr %[[OMP_PAR_ARG]], i32 0, i32 0
+// CHECK: store ptr %[[ORIG]], ptr %[[ORIG_GEP]], align 8
+// CHECK: call void (ptr, i32, ptr, ...) @__kmpc_fork_call(ptr @1, i32 1, ptr @parallel_op_1_private..omp_par, ptr %[[OMP_PAR_ARG]])
+// CHECK: }
+
+// CHECK-LABEL: void @parallel_op_1_private..omp_par
+// CHECK-SAME: (ptr noalias %{{.*}}, ptr noalias %{{.*}}, ptr %[[ARG:.*]])
+// CHECK: %[[ORIG_PTR_PTR:.*]] = getelementptr { ptr }, ptr %[[ARG]], i32 0, i32 0
+// CHECK: %[[ORIG_PTR:.*]] = load ptr, ptr %[[ORIG_PTR_PTR]], align 8
+
+// Check that the privatizer alloc region was inlined properly.
+// CHECK: %[[PRIV_ALLOC:.*]] = alloca float, align 4
+// CHECK: %[[ORIG_VAL:.*]] = load float, ptr %[[ORIG_PTR]], align 4
+// CHECK: store float %[[ORIG_VAL]], ptr %[[PRIV_ALLOC]], align 4
+// CHECK-NEXT: br
+
+// Check that the privatized value is used (rather than the original one).
+// CHECK: load float, ptr %[[PRIV_ALLOC]], align 4
+// CHECK: }
+
+llvm.func @parallel_op_2_privates(%arg0: !llvm.ptr, %arg1: !llvm.ptr) {
+ omp.parallel private(@x.privatizer %arg0 -> %arg2 : !llvm.ptr, @y.privatizer %arg1 -> %arg3 : !llvm.ptr) {
+ %0 = llvm.load %arg2 : !llvm.ptr -> f32
+ %1 = llvm.load %arg3 : !llvm.ptr -> i32
+ omp.terminator
+ }
+ llvm.return
+}
+
+// CHECK-LABEL: @parallel_op_2_privates
+// CHECK-SAME: (ptr %[[ORIG1:.*]], ptr %[[ORIG2:.*]]) {
+// CHECK: %[[OMP_PAR_ARG:.*]] = alloca { ptr, ptr }, align 8
+// CHECK: %[[ORIG1_GEP:.*]] = getelementptr { ptr, ptr }, ptr %[[OMP_PAR_ARG]], i32 0, i32 0
+// CHECK: store ptr %[[ORIG1]], ptr %[[ORIG1_GEP]], align 8
+// CHECK: call void (ptr, i32, ptr, ...) @__kmpc_fork_call(ptr @1, i32 1, ptr @parallel_op_2_privates..omp_par, ptr %[[OMP_PAR_ARG]])
+// CHECK: }
+
+// CHECK-LABEL: void @parallel_op_2_privates..omp_par
+// CHECK-SAME: (ptr noalias %{{.*}}, ptr noalias %{{.*}}, ptr %[[ARG:.*]])
+// CHECK: %[[ORIG1_PTR_PTR:.*]] = getelementptr { ptr, ptr }, ptr %[[ARG]], i32 0, i32 0
+// CHECK: %[[ORIG1_PTR:.*]] = load ptr, ptr %[[ORIG1_PTR_PTR]], align 8
+// CHECK: %[[ORIG2_PTR_PTR:.*]] = getelementptr { ptr, ptr }, ptr %[[ARG]], i32 0, i32 1
+// CHECK: %[[ORIG2_PTR:.*]] = load ptr, ptr %[[ORIG2_PTR_PTR]], align 8
+
+// Check that the privatizer alloc region was inlined properly.
+// CHECK: %[[PRIV1_ALLOC:.*]] = alloca float, align 4
+// CHECK: %[[ORIG1_VAL:.*]] = load float, ptr %[[ORIG1_PTR]], align 4
+// CHECK: store float %[[ORIG1_VAL]], ptr %[[PRIV1_ALLOC]], align 4
+// CHECK: %[[PRIV2_ALLOC:.*]] = alloca i32, align 4
+// CHECK: %[[ORIG2_VAL:.*]] = load i32, ptr %[[ORIG2_PTR]], align 4
+// CHECK: store i32 %[[ORIG2_VAL]], ptr %[[PRIV2_ALLOC]], align 4
+// CHECK-NEXT: br
+
+// Check that the privatized value is used (rather than the original one).
+// CHECK: load float, ptr %[[PRIV1_ALLOC]], align 4
+// CHECK: load i32, ptr %[[PRIV2_ALLOC]], align 4
+// CHECK: }
+
+omp.private {type = private} @x.privatizer : !llvm.ptr alloc {
+^bb0(%arg0: !llvm.ptr):
+ %c1 = llvm.mlir.constant(1 : i32) : i32
+ %0 = llvm.alloca %c1 x f32 : (i32) -> !llvm.ptr
+ %1 = llvm.load %arg0 : !llvm.ptr -> f32
+ llvm.store %1, %0 : f32, !llvm.ptr
+ omp.yield(%0 : !llvm.ptr)
+}
+
+omp.private {type = private} @y.privatizer : !llvm.ptr alloc {
+^bb0(%arg0: !llvm.ptr):
+ %c1 = llvm.mlir.constant(1 : i32) : i32
+ %0 = llvm.alloca %c1 x i32 : (i32) -> !llvm.ptr
+ %1 = llvm.load %arg0 : !llvm.ptr -> i32
+ llvm.store %1, %0 : i32, !llvm.ptr
+ omp.yield(%0 : !llvm.ptr)
+}
+
+// -----
+
+llvm.func @parallel_op_private_multi_block(%arg0: !llvm.ptr) {
+ omp.parallel private(@multi_block.privatizer %arg0 -> %arg2 : !llvm.ptr) {
+ %0 = llvm.load %arg2 : !llvm.ptr -> f32
+ omp.terminator
+ }
+ llvm.return
+}
+
+// CHECK-LABEL: define internal void @parallel_op_private_multi_block..omp_par
+// CHECK: omp.par.entry:
+// CHECK: %[[ORIG_PTR_PTR:.*]] = getelementptr { ptr }, ptr %{{.*}}, i32 0, i32 0
+// CHECK: %[[ORIG_PTR:.*]] = load ptr, ptr %[[ORIG_PTR_PTR]], align 8
+// CHECK: br label %[[PRIV_BB1:.*]]
+
+// Check contents of the first block in the `alloc` region.
+// CHECK: [[PRIV_BB1]]:
+// CHECK-NEXT: %[[PRIV_ALLOC:.*]] = alloca float, align 4
+// CHECK-NEXT: br label %[[PRIV_BB2:.*]]
+
+// Check contents of the second block in the `alloc` region.
+// CHECK: [[PRIV_BB2]]:
+// CHECK-NEXT: %[[ORIG_PTR2:.*]] = phi ptr [ %[[ORIG_PTR]], %[[PRIV_BB1]] ]
+// CHECK-NEXT: %[[PRIV_ALLOC2:.*]] = phi ptr [ %[[PRIV_ALLOC]], %[[PRIV_BB1]] ]
+// CHECK-NEXT: %[[ORIG_VAL:.*]] = load float, ptr %[[ORIG_PTR2]], align 4
+// CHECK-NEXT: store float %[[ORIG_VAL]], ptr %[[PRIV_ALLOC2]], align 4
+// CHECK-NEXT: br label %[[PRIV_CONT:.*]]
+
+// Check that the privatizer's continuation block yileds the private clone's
+// address.
+// CHECK: [[PRIV_CONT]]:
+// CHECK-NEXT: %[[PRIV_ALLOC3:.*]] = phi ptr [ %[[PRIV_ALLOC2]], %[[PRIV_BB2]] ]
+// CHECK-NEXT: br label %[[PAR_REG:.*]]
+
+// Check that the body of the parallel region loads from the private clone.
+// CHECK: [[PAR_REG]]:
+// CHECK: %{{.*}} = load float, ptr %[[PRIV_ALLOC3]], align 4
+
+omp.private {type = private} @multi_block.privatizer : !llvm.ptr alloc {
+^bb0(%arg0: !llvm.ptr):
+ %c1 = llvm.mlir.constant(1 : i32) : i32
+ %0 = llvm.alloca %c1 x f32 : (i32) -> !llvm.ptr
+ llvm.br ^bb1(%arg0, %0 : !llvm.ptr, !llvm.ptr)
+
+^bb1(%arg1: !llvm.ptr, %arg2: !llvm.ptr):
+ %1 = llvm.load %arg1 : !llvm.ptr -> f32
+ llvm.store %1, %arg2 : f32, !llvm.ptr
+ omp.yield(%arg2 : !llvm.ptr)
+}
>From d2d1ee0323ad74d7f03efba7f68efe9a9bd37da3 Mon Sep 17 00:00:00 2001
From: ergawy <kareem.ergawy at amd.com>
Date: Thu, 22 Feb 2024 22:41:37 -0600
Subject: [PATCH 2/2] Add RAII object to manage mapping of the op's arguments.
---
.../OpenMP/OpenMPToLLVMIRTranslation.cpp | 105 +++++++++---------
1 file changed, 55 insertions(+), 50 deletions(-)
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 0c390f68bb6890..8c20689c4a39dd 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -1011,40 +1011,49 @@ convertOmpWsLoop(Operation &opInst, llvm::IRBuilderBase &builder,
return success();
}
-/// Replace the region arguments of the parallel op (which correspond to private
-/// variables) with the actual private variables they correspond to. This
-/// prepares the parallel op so that it matches what is expected by the
-/// OMPIRBuilder. Instead of editing the original op in-place, this function
-/// does the required changes to a cloned version which should then be erased by
-/// the caller.
-static omp::ParallelOp
-prepareOmpParallelForPrivatization(omp::ParallelOp opInst) {
- Region ®ion = opInst.getRegion();
- auto privateVars = opInst.getPrivateVars();
-
- auto privateVarsIt = privateVars.begin();
- // Reduction precede private arguments, so skip them first.
- unsigned privateArgBeginIdx = opInst.getNumReductionVars();
- unsigned privateArgEndIdx = privateArgBeginIdx + privateVars.size();
-
- mlir::IRMapping mapping;
- for (size_t argIdx = privateArgBeginIdx; argIdx < privateArgEndIdx;
- ++argIdx, ++privateVarsIt)
- mapping.map(region.getArgument(argIdx), *privateVarsIt);
-
- mlir::OpBuilder cloneBuilder(opInst);
- omp::ParallelOp opInstClone =
- llvm::cast<omp::ParallelOp>(cloneBuilder.clone(*opInst, mapping));
-
- return opInstClone;
-}
+/// A RAII class that on construction replaces the region arguments of the
+/// parallel op (which correspond to private variables) with the actual private
+/// variables they correspond to. This prepares the parallel op so that it
+/// matches what is expected by the OMPIRBuilder.
+///
+/// On destruction, it restores the original state of the operation so that on
+/// the MLIR side, the op is not affected by conversion to LLVM IR.
+class OmpParallelOpConversionManager {
+public:
+ OmpParallelOpConversionManager(omp::ParallelOp opInst)
+ : region(opInst.getRegion()), privateVars(opInst.getPrivateVars()),
+ privateArgBeginIdx(opInst.getNumReductionVars()),
+ privateArgEndIdx(privateArgBeginIdx + privateVars.size()) {
+ auto privateVarsIt = privateVars.begin();
+
+ for (size_t argIdx = privateArgBeginIdx; argIdx < privateArgEndIdx;
+ ++argIdx, ++privateVarsIt)
+ mlir::replaceAllUsesInRegionWith(region.getArgument(argIdx),
+ *privateVarsIt, region);
+ }
+
+ ~OmpParallelOpConversionManager() {
+ auto privateVarsIt = privateVars.begin();
+
+ for (size_t argIdx = privateArgBeginIdx; argIdx < privateArgEndIdx;
+ ++argIdx, ++privateVarsIt)
+ mlir::replaceAllUsesInRegionWith(*privateVarsIt,
+ region.getArgument(argIdx), region);
+ }
+
+private:
+ Region ®ion;
+ OperandRange privateVars;
+ unsigned privateArgBeginIdx;
+ unsigned privateArgEndIdx;
+};
/// Converts the OpenMP parallel operation to LLVM IR.
static LogicalResult
convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &moduleTranslation) {
using InsertPointTy = llvm::OpenMPIRBuilder::InsertPointTy;
- omp::ParallelOp opInstClone = prepareOmpParallelForPrivatization(opInst);
+ OmpParallelOpConversionManager raii(opInst);
// TODO: support error propagation in OpenMPIRBuilder and use it instead of
// relying on captured variables.
@@ -1054,12 +1063,12 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
auto bodyGenCB = [&](InsertPointTy allocaIP, InsertPointTy codeGenIP) {
// Collect reduction declarations
SmallVector<omp::ReductionDeclareOp> reductionDecls;
- collectReductionDecls(opInstClone, reductionDecls);
+ collectReductionDecls(opInst, reductionDecls);
// Allocate reduction vars
SmallVector<llvm::Value *> privateReductionVariables;
DenseMap<Value, llvm::Value *> reductionVariableMap;
- allocReductionVars(opInstClone, builder, moduleTranslation, allocaIP,
+ allocReductionVars(opInst, builder, moduleTranslation, allocaIP,
reductionDecls, privateReductionVariables,
reductionVariableMap);
@@ -1071,7 +1080,7 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// Initialize reduction vars
builder.restoreIP(allocaIP);
- for (unsigned i = 0; i < opInstClone.getNumReductionVars(); ++i) {
+ for (unsigned i = 0; i < opInst.getNumReductionVars(); ++i) {
SmallVector<llvm::Value *> phis;
if (failed(inlineConvertOmpRegions(
reductionDecls[i].getInitializerRegion(), "omp.reduction.neutral",
@@ -1092,19 +1101,18 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// ParallelOp has only one region associated with it.
builder.restoreIP(codeGenIP);
auto regionBlock =
- convertOmpOpRegions(opInstClone.getRegion(), "omp.par.region", builder,
+ convertOmpOpRegions(opInst.getRegion(), "omp.par.region", builder,
moduleTranslation, bodyGenStatus);
// Process the reductions if required.
- if (opInstClone.getNumReductionVars() > 0) {
+ if (opInst.getNumReductionVars() > 0) {
// Collect reduction info
SmallVector<OwningReductionGen> owningReductionGens;
SmallVector<OwningAtomicReductionGen> owningAtomicReductionGens;
SmallVector<llvm::OpenMPIRBuilder::ReductionInfo> reductionInfos;
- collectReductionInfo(opInstClone, builder, moduleTranslation,
- reductionDecls, owningReductionGens,
- owningAtomicReductionGens, privateReductionVariables,
- reductionInfos);
+ collectReductionInfo(opInst, builder, moduleTranslation, reductionDecls,
+ owningReductionGens, owningAtomicReductionGens,
+ privateReductionVariables, reductionInfos);
// Move to region cont block
builder.SetInsertPoint(regionBlock->getTerminator());
@@ -1117,8 +1125,7 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
ompBuilder->createReductions(builder.saveIP(), allocaIP,
reductionInfos, false);
if (!contInsertPoint.getBlock()) {
- bodyGenStatus = opInstClone->emitOpError()
- << "failed to convert reductions";
+ bodyGenStatus = opInst->emitOpError() << "failed to convert reductions";
return;
}
@@ -1140,9 +1147,9 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
// returned.
auto [privVar, privatizerClone] =
[&]() -> std::pair<mlir::Value, omp::PrivateClauseOp> {
- if (!opInstClone.getPrivateVars().empty()) {
- auto privVars = opInstClone.getPrivateVars();
- auto privatizers = opInstClone.getPrivatizers();
+ if (!opInst.getPrivateVars().empty()) {
+ auto privVars = opInst.getPrivateVars();
+ auto privatizers = opInst.getPrivatizers();
for (auto [privVar, privatizerAttr] :
llvm::zip_equal(privVars, *privatizers)) {
@@ -1155,7 +1162,7 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
SymbolRefAttr privSym = llvm::cast<SymbolRefAttr>(privatizerAttr);
omp::PrivateClauseOp privatizer =
SymbolTable::lookupNearestSymbolFrom<omp::PrivateClauseOp>(
- opInstClone, privSym);
+ opInst, privSym);
// Clone the privatizer in case it is used by more than one parallel
// region. The privatizer is processed in-place (see below) before it
@@ -1192,9 +1199,8 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
SmallVector<llvm::Value *, 1> yieldedValues;
if (failed(inlineConvertOmpRegions(allocRegion, "omp.privatizer", builder,
moduleTranslation, &yieldedValues))) {
- opInstClone.emitError(
- "failed to inline `alloc` region of an `omp.private` "
- "op in the parallel region");
+ opInst.emitError("failed to inline `alloc` region of an `omp.private` "
+ "op in the parallel region");
bodyGenStatus = failure();
} else {
assert(yieldedValues.size() == 1);
@@ -1213,13 +1219,13 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
auto finiCB = [&](InsertPointTy codeGenIP) {};
llvm::Value *ifCond = nullptr;
- if (auto ifExprVar = opInstClone.getIfExprVar())
+ if (auto ifExprVar = opInst.getIfExprVar())
ifCond = moduleTranslation.lookupValue(ifExprVar);
llvm::Value *numThreads = nullptr;
- if (auto numThreadsVar = opInstClone.getNumThreadsVar())
+ if (auto numThreadsVar = opInst.getNumThreadsVar())
numThreads = moduleTranslation.lookupValue(numThreadsVar);
auto pbKind = llvm::omp::OMP_PROC_BIND_default;
- if (auto bind = opInstClone.getProcBindVal())
+ if (auto bind = opInst.getProcBindVal())
pbKind = getProcBindKind(*bind);
// TODO: Is the Parallel construct cancellable?
bool isCancellable = false;
@@ -1232,7 +1238,6 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
ompBuilder->createParallel(ompLoc, allocaIP, bodyGenCB, privCB, finiCB,
ifCond, numThreads, pbKind, isCancellable));
- opInstClone.erase();
return bodyGenStatus;
}
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