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[flang][OpenMP] Convert DataSharingProcessor to omp::Clause #81629

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Mar 15, 2024
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[flang][OpenMP] Convert DataSharingProcessor to omp::Clause #81629

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12 changes: 6 additions & 6 deletions flang/lib/Lower/OpenMP/Clauses.h
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,12 @@ getBaseObject(const Object &object,
Fortran::semantics::SemanticsContext &semaCtx);

namespace clause {
using DefinedOperator = tomp::clause::DefinedOperatorT<SymIdent, SymReference>;
using ProcedureDesignator =
tomp::clause::ProcedureDesignatorT<SymIdent, SymReference>;
using ReductionOperator =
tomp::clause::ReductionOperatorT<SymIdent, SymReference>;

#ifdef EMPTY_CLASS
#undef EMPTY_CLASS
#endif
Expand All @@ -124,12 +130,6 @@ namespace clause {
#undef EMPTY_CLASS
#undef WRAPPER_CLASS

using DefinedOperator = tomp::clause::DefinedOperatorT<SymIdent, SymReference>;
using ProcedureDesignator =
tomp::clause::ProcedureDesignatorT<SymIdent, SymReference>;
using ReductionOperator =
tomp::clause::ReductionOperatorT<SymIdent, SymReference>;

// "Requires" clauses are handled early on, and the aggregated information
// is stored in the Symbol details of modules, programs, and subprograms.
// These clauses are still handled here to cover all alternatives in the
Expand Down
287 changes: 139 additions & 148 deletions flang/lib/Lower/OpenMP/DataSharingProcessor.cpp
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Expand Up @@ -81,30 +81,26 @@ void DataSharingProcessor::copyLastPrivateSymbol(
}

void DataSharingProcessor::collectOmpObjectListSymbol(
const Fortran::parser::OmpObjectList &ompObjectList,
const omp::ObjectList &objects,
llvm::SetVector<const Fortran::semantics::Symbol *> &symbolSet) {
for (const Fortran::parser::OmpObject &ompObject : ompObjectList.v) {
Fortran::semantics::Symbol *sym = getOmpObjectSymbol(ompObject);
symbolSet.insert(sym);
}
for (const omp::Object &object : objects)
symbolSet.insert(object.id());
}

void DataSharingProcessor::collectSymbolsForPrivatization() {
bool hasCollapse = false;
for (const Fortran::parser::OmpClause &clause : opClauseList.v) {
for (const omp::Clause &clause : clauses) {
if (const auto &privateClause =
std::get_if<Fortran::parser::OmpClause::Private>(&clause.u)) {
std::get_if<omp::clause::Private>(&clause.u)) {
collectOmpObjectListSymbol(privateClause->v, privatizedSymbols);
} else if (const auto &firstPrivateClause =
std::get_if<Fortran::parser::OmpClause::Firstprivate>(
&clause.u)) {
std::get_if<omp::clause::Firstprivate>(&clause.u)) {
collectOmpObjectListSymbol(firstPrivateClause->v, privatizedSymbols);
} else if (const auto &lastPrivateClause =
std::get_if<Fortran::parser::OmpClause::Lastprivate>(
&clause.u)) {
std::get_if<omp::clause::Lastprivate>(&clause.u)) {
collectOmpObjectListSymbol(lastPrivateClause->v, privatizedSymbols);
hasLastPrivateOp = true;
} else if (std::get_if<Fortran::parser::OmpClause::Collapse>(&clause.u)) {
} else if (std::get_if<omp::clause::Collapse>(&clause.u)) {
hasCollapse = true;
}
}
Expand Down Expand Up @@ -137,138 +133,135 @@ void DataSharingProcessor::insertBarrier() {
void DataSharingProcessor::insertLastPrivateCompare(mlir::Operation *op) {
bool cmpCreated = false;
mlir::OpBuilder::InsertPoint localInsPt = firOpBuilder.saveInsertionPoint();
for (const Fortran::parser::OmpClause &clause : opClauseList.v) {
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Are there code changes here or is it only the replacement of parser::OmpClause with omp::Clause?

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The code functionality is unchanged. One reason for the seemingly large differences in the diff is that I replaced the if (get_if<LastPrivate>) with if (!get_if<Lastprivate>) continue; to reduce indentation.

if (std::get_if<Fortran::parser::OmpClause::Lastprivate>(&clause.u)) {
// TODO: Add lastprivate support for simd construct
if (mlir::isa<mlir::omp::SectionOp>(op)) {
if (&eval == &eval.parentConstruct->getLastNestedEvaluation()) {
// For `omp.sections`, lastprivatized variables occur in
// lexically final `omp.section` operation. The following FIR
// shall be generated for the same:
//
// omp.sections lastprivate(...) {
// omp.section {...}
// omp.section {...}
// omp.section {
// fir.allocate for `private`/`firstprivate`
// <More operations here>
// fir.if %true {
// ^%lpv_update_blk
// }
// }
// }
//
// To keep code consistency while handling privatization
// through this control flow, add a `fir.if` operation
// that always evaluates to true, in order to create
// a dedicated sub-region in `omp.section` where
// lastprivate FIR can reside. Later canonicalizations
// will optimize away this operation.
if (!eval.lowerAsUnstructured()) {
auto ifOp = firOpBuilder.create<fir::IfOp>(
op->getLoc(),
firOpBuilder.createIntegerConstant(
op->getLoc(), firOpBuilder.getIntegerType(1), 0x1),
/*else*/ false);
firOpBuilder.setInsertionPointToStart(
&ifOp.getThenRegion().front());

const Fortran::parser::OpenMPConstruct *parentOmpConstruct =
eval.parentConstruct->getIf<Fortran::parser::OpenMPConstruct>();
assert(parentOmpConstruct &&
"Expected a valid enclosing OpenMP construct");
const Fortran::parser::OpenMPSectionsConstruct *sectionsConstruct =
std::get_if<Fortran::parser::OpenMPSectionsConstruct>(
&parentOmpConstruct->u);
assert(sectionsConstruct &&
"Expected an enclosing omp.sections construct");
const Fortran::parser::OmpClauseList &sectionsEndClauseList =
std::get<Fortran::parser::OmpClauseList>(
std::get<Fortran::parser::OmpEndSectionsDirective>(
sectionsConstruct->t)
.t);
for (const Fortran::parser::OmpClause &otherClause :
sectionsEndClauseList.v)
if (std::get_if<Fortran::parser::OmpClause::Nowait>(
&otherClause.u))
// Emit implicit barrier to synchronize threads and avoid data
// races on post-update of lastprivate variables when `nowait`
// clause is present.
firOpBuilder.create<mlir::omp::BarrierOp>(
converter.getCurrentLocation());
firOpBuilder.setInsertionPointToStart(
&ifOp.getThenRegion().front());
lastPrivIP = firOpBuilder.saveInsertionPoint();
firOpBuilder.setInsertionPoint(ifOp);
insPt = firOpBuilder.saveInsertionPoint();
} else {
// Lastprivate operation is inserted at the end
// of the lexically last section in the sections
// construct
mlir::OpBuilder::InsertPoint unstructuredSectionsIP =
firOpBuilder.saveInsertionPoint();
mlir::Operation *lastOper = op->getRegion(0).back().getTerminator();
firOpBuilder.setInsertionPoint(lastOper);
lastPrivIP = firOpBuilder.saveInsertionPoint();
firOpBuilder.restoreInsertionPoint(unstructuredSectionsIP);
}
}
} else if (mlir::isa<mlir::omp::WsLoopOp>(op)) {
// Update the original variable just before exiting the worksharing
// loop. Conversion as follows:
for (const omp::Clause &clause : clauses) {
if (clause.id != llvm::omp::OMPC_lastprivate)
continue;
// TODO: Add lastprivate support for simd construct
if (mlir::isa<mlir::omp::SectionOp>(op)) {
if (&eval == &eval.parentConstruct->getLastNestedEvaluation()) {
// For `omp.sections`, lastprivatized variables occur in
// lexically final `omp.section` operation. The following FIR
// shall be generated for the same:
//
// omp.wsloop {
// omp.wsloop { ...
// ... store
// store ===> %v = arith.addi %iv, %step
// omp.yield %cmp = %step < 0 ? %v < %ub : %v > %ub
// } fir.if %cmp {
// fir.store %v to %loopIV
// ^%lpv_update_blk:
// }
// omp.yield
// }
// omp.sections lastprivate(...) {
// omp.section {...}
// omp.section {...}
// omp.section {
// fir.allocate for `private`/`firstprivate`
// <More operations here>
// fir.if %true {
// ^%lpv_update_blk
// }
// }
// }
//

// Only generate the compare once in presence of multiple LastPrivate
// clauses.
if (cmpCreated)
continue;
cmpCreated = true;

mlir::Location loc = op->getLoc();
mlir::Operation *lastOper = op->getRegion(0).back().getTerminator();
firOpBuilder.setInsertionPoint(lastOper);

mlir::Value iv = op->getRegion(0).front().getArguments()[0];
mlir::Value ub =
mlir::dyn_cast<mlir::omp::WsLoopOp>(op).getUpperBound()[0];
mlir::Value step = mlir::dyn_cast<mlir::omp::WsLoopOp>(op).getStep()[0];

// v = iv + step
// cmp = step < 0 ? v < ub : v > ub
mlir::Value v = firOpBuilder.create<mlir::arith::AddIOp>(loc, iv, step);
mlir::Value zero =
firOpBuilder.createIntegerConstant(loc, step.getType(), 0);
mlir::Value negativeStep = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::slt, step, zero);
mlir::Value vLT = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::slt, v, ub);
mlir::Value vGT = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::sgt, v, ub);
mlir::Value cmpOp = firOpBuilder.create<mlir::arith::SelectOp>(
loc, negativeStep, vLT, vGT);

auto ifOp = firOpBuilder.create<fir::IfOp>(loc, cmpOp, /*else*/ false);
firOpBuilder.setInsertionPointToStart(&ifOp.getThenRegion().front());
assert(loopIV && "loopIV was not set");
firOpBuilder.create<fir::StoreOp>(op->getLoc(), v, loopIV);
lastPrivIP = firOpBuilder.saveInsertionPoint();
} else {
TODO(converter.getCurrentLocation(),
"lastprivate clause in constructs other than "
"simd/worksharing-loop");
// To keep code consistency while handling privatization
// through this control flow, add a `fir.if` operation
// that always evaluates to true, in order to create
// a dedicated sub-region in `omp.section` where
// lastprivate FIR can reside. Later canonicalizations
// will optimize away this operation.
if (!eval.lowerAsUnstructured()) {
auto ifOp = firOpBuilder.create<fir::IfOp>(
op->getLoc(),
firOpBuilder.createIntegerConstant(
op->getLoc(), firOpBuilder.getIntegerType(1), 0x1),
/*else*/ false);
firOpBuilder.setInsertionPointToStart(&ifOp.getThenRegion().front());

const Fortran::parser::OpenMPConstruct *parentOmpConstruct =
eval.parentConstruct->getIf<Fortran::parser::OpenMPConstruct>();
assert(parentOmpConstruct &&
"Expected a valid enclosing OpenMP construct");
const Fortran::parser::OpenMPSectionsConstruct *sectionsConstruct =
std::get_if<Fortran::parser::OpenMPSectionsConstruct>(
&parentOmpConstruct->u);
assert(sectionsConstruct &&
"Expected an enclosing omp.sections construct");
const Fortran::parser::OmpClauseList &sectionsEndClauseList =
std::get<Fortran::parser::OmpClauseList>(
std::get<Fortran::parser::OmpEndSectionsDirective>(
sectionsConstruct->t)
.t);
for (const Fortran::parser::OmpClause &otherClause :
sectionsEndClauseList.v)
if (std::get_if<Fortran::parser::OmpClause::Nowait>(&otherClause.u))
// Emit implicit barrier to synchronize threads and avoid data
// races on post-update of lastprivate variables when `nowait`
// clause is present.
firOpBuilder.create<mlir::omp::BarrierOp>(
converter.getCurrentLocation());
firOpBuilder.setInsertionPointToStart(&ifOp.getThenRegion().front());
lastPrivIP = firOpBuilder.saveInsertionPoint();
firOpBuilder.setInsertionPoint(ifOp);
insPt = firOpBuilder.saveInsertionPoint();
} else {
// Lastprivate operation is inserted at the end
// of the lexically last section in the sections
// construct
mlir::OpBuilder::InsertPoint unstructuredSectionsIP =
firOpBuilder.saveInsertionPoint();
mlir::Operation *lastOper = op->getRegion(0).back().getTerminator();
firOpBuilder.setInsertionPoint(lastOper);
lastPrivIP = firOpBuilder.saveInsertionPoint();
firOpBuilder.restoreInsertionPoint(unstructuredSectionsIP);
}
}
} else if (mlir::isa<mlir::omp::WsLoopOp>(op)) {
// Update the original variable just before exiting the worksharing
// loop. Conversion as follows:
//
// omp.wsloop {
// omp.wsloop { ...
// ... store
// store ===> %v = arith.addi %iv, %step
// omp.yield %cmp = %step < 0 ? %v < %ub : %v > %ub
// } fir.if %cmp {
// fir.store %v to %loopIV
// ^%lpv_update_blk:
// }
// omp.yield
// }
//

// Only generate the compare once in presence of multiple LastPrivate
// clauses.
if (cmpCreated)
continue;
cmpCreated = true;

mlir::Location loc = op->getLoc();
mlir::Operation *lastOper = op->getRegion(0).back().getTerminator();
firOpBuilder.setInsertionPoint(lastOper);

mlir::Value iv = op->getRegion(0).front().getArguments()[0];
mlir::Value ub =
mlir::dyn_cast<mlir::omp::WsLoopOp>(op).getUpperBound()[0];
mlir::Value step = mlir::dyn_cast<mlir::omp::WsLoopOp>(op).getStep()[0];

// v = iv + step
// cmp = step < 0 ? v < ub : v > ub
mlir::Value v = firOpBuilder.create<mlir::arith::AddIOp>(loc, iv, step);
mlir::Value zero =
firOpBuilder.createIntegerConstant(loc, step.getType(), 0);
mlir::Value negativeStep = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::slt, step, zero);
mlir::Value vLT = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::slt, v, ub);
mlir::Value vGT = firOpBuilder.create<mlir::arith::CmpIOp>(
loc, mlir::arith::CmpIPredicate::sgt, v, ub);
mlir::Value cmpOp = firOpBuilder.create<mlir::arith::SelectOp>(
loc, negativeStep, vLT, vGT);

auto ifOp = firOpBuilder.create<fir::IfOp>(loc, cmpOp, /*else*/ false);
firOpBuilder.setInsertionPointToStart(&ifOp.getThenRegion().front());
assert(loopIV && "loopIV was not set");
firOpBuilder.create<fir::StoreOp>(op->getLoc(), v, loopIV);
lastPrivIP = firOpBuilder.saveInsertionPoint();
} else {
TODO(converter.getCurrentLocation(),
"lastprivate clause in constructs other than "
"simd/worksharing-loop");
}
}
firOpBuilder.restoreInsertionPoint(localInsPt);
Expand All @@ -292,14 +285,12 @@ void DataSharingProcessor::collectSymbols(
}

void DataSharingProcessor::collectDefaultSymbols() {
for (const Fortran::parser::OmpClause &clause : opClauseList.v) {
if (const auto &defaultClause =
std::get_if<Fortran::parser::OmpClause::Default>(&clause.u)) {
if (defaultClause->v.v ==
Fortran::parser::OmpDefaultClause::Type::Private)
for (const omp::Clause &clause : clauses) {
if (const auto *defaultClause =
std::get_if<omp::clause::Default>(&clause.u)) {
if (defaultClause->v == omp::clause::Default::Type::Private)
collectSymbols(Fortran::semantics::Symbol::Flag::OmpPrivate);
else if (defaultClause->v.v ==
Fortran::parser::OmpDefaultClause::Type::Firstprivate)
else if (defaultClause->v == omp::clause::Default::Type::Firstprivate)
collectSymbols(Fortran::semantics::Symbol::Flag::OmpFirstPrivate);
}
}
Expand Down
12 changes: 7 additions & 5 deletions flang/lib/Lower/OpenMP/DataSharingProcessor.h
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Expand Up @@ -12,6 +12,7 @@
#ifndef FORTRAN_LOWER_DATASHARINGPROCESSOR_H
#define FORTRAN_LOWER_DATASHARINGPROCESSOR_H

#include "Clauses.h"
#include "flang/Lower/AbstractConverter.h"
#include "flang/Lower/OpenMP.h"
#include "flang/Optimizer/Builder/FIRBuilder.h"
Expand Down Expand Up @@ -52,7 +53,7 @@ class DataSharingProcessor {
llvm::SetVector<const Fortran::semantics::Symbol *> symbolsInParentRegions;
Fortran::lower::AbstractConverter &converter;
fir::FirOpBuilder &firOpBuilder;
const Fortran::parser::OmpClauseList &opClauseList;
omp::List<omp::Clause> clauses;
Fortran::lower::pft::Evaluation &eval;
bool useDelayedPrivatization;
Fortran::lower::SymMap *symTable;
Expand All @@ -61,7 +62,7 @@ class DataSharingProcessor {
bool needBarrier();
void collectSymbols(Fortran::semantics::Symbol::Flag flag);
void collectOmpObjectListSymbol(
const Fortran::parser::OmpObjectList &ompObjectList,
const omp::ObjectList &objects,
llvm::SetVector<const Fortran::semantics::Symbol *> &symbolSet);
void collectSymbolsForPrivatization();
void insertBarrier();
Expand All @@ -81,14 +82,15 @@ class DataSharingProcessor {

public:
DataSharingProcessor(Fortran::lower::AbstractConverter &converter,
Fortran::semantics::SemanticsContext &semaCtx,
const Fortran::parser::OmpClauseList &opClauseList,
Fortran::lower::pft::Evaluation &eval,
bool useDelayedPrivatization = false,
Fortran::lower::SymMap *symTable = nullptr)
: hasLastPrivateOp(false), converter(converter),
firOpBuilder(converter.getFirOpBuilder()), opClauseList(opClauseList),
eval(eval), useDelayedPrivatization(useDelayedPrivatization),
symTable(symTable) {}
firOpBuilder(converter.getFirOpBuilder()),
clauses(omp::makeList(opClauseList, semaCtx)), eval(eval),
useDelayedPrivatization(useDelayedPrivatization), symTable(symTable) {}

// Privatisation is split into two steps.
// Step1 performs cloning of all privatisation clauses and copying for
Expand Down
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