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[flang][OpenMP] - Transform target offloading directives with dependencies during PFT to MLIR conversion #85130

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[flang][OpenMP] - Transform target offloading directives with dependencies during PFT to MLIR conversion #85130

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dc4f90d
[mlir][OpenMP] - Transform target offloading directives with dependen…
bhandarkar-pranav Mar 13, 2024
b1d66da
Handle nowait and use it to add an if clause when creating an outer t…
bhandarkar-pranav Apr 30, 2024
b5d2c84
[mlir][OpenMP] - Transform target offloading directives with dependen…
bhandarkar-pranav Mar 13, 2024
028fd9c
update flang/test/Lower/OpenMP/target.f90
bhandarkar-pranav Apr 30, 2024
8ec3853
Add an opemp flang lowering test that uses the target construct with …
bhandarkar-pranav Apr 30, 2024
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55 changes: 55 additions & 0 deletions flang/lib/Lower/OpenMP/ClauseProcessor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -761,6 +761,61 @@ bool ClauseProcessor::processHasDeviceAddr(
addUseDeviceClause(converter, devAddrClause.v, result.hasDeviceAddrVars,
isDeviceTypes, isDeviceLocs, isDeviceSymbols);
});

}

bool ClauseProcessor::processTargetDepend(
mlir::Location currentLocation, mlir::omp::DependClauseOps &clauseOps) const {

processDepend(clauseOps);
if (clauseOps.dependTypeAttrs.empty())
return false;

// If 'dependTypeOperands' is not empty, this means the depend
// clause was used and we create an omp.task operation that'll
// enclose the omp.target operation corresponding to the target
// construct used. This new omp.task will be a mergeable task
// on which the depend clause will be tacked on. The depend
// clause on the original target construct is dropped.
fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();

// Create the new omp.task op.
// Whether we create a mergeable task or not depends upon the presence of the
// nowait clause on the target construct.
// If the nowait clause is not present on the target construct, then as per
// the spec, the target task is an included task. We add if(0) clause to the
// task that we create. A task with an if clause that evaluates to false is
// undeferred and because this value is known at compile time, it is an
// included task. And an included task is also mergeable. So, we don't bother
// with the mergeable clause here. If the nowait clause is present on the
// target construct, then as per the spec, the execution of the target task
// may be deferred. This makes it trivially not mergeable.
mlir::omp::NowaitClauseOps nowaitClauseOp;
markClauseOccurrence<omp::clause::Nowait>(nowaitClauseOp.nowaitAttr);

mlir::omp::TaskOp taskOp = firOpBuilder.create<mlir::omp::TaskOp>(
currentLocation,
/*if_expr*/ nowaitClauseOp.nowaitAttr
? firOpBuilder.createBool(currentLocation, true)
: firOpBuilder.createBool(currentLocation, false),
/*final_expr*/ mlir::Value(), /*untied*/ mlir::UnitAttr(),
/*mergeable*/ mlir::UnitAttr(),
/*in_reduction_vars*/ mlir::ValueRange(), /*in_reductions*/ nullptr,
/*priority*/ mlir::Value(),
mlir::ArrayAttr::get(converter.getFirOpBuilder().getContext(),
clauseOps.dependTypeAttrs),
clauseOps.dependVars, /*allocate_vars*/ mlir::ValueRange(),
/*allocate_vars*/ mlir::ValueRange());

// Clear the dependencies so that the subsequent omp.target op doesn't have
// dependencies
clauseOps.dependTypeAttrs.clear();
clauseOps.dependVars.clear();

firOpBuilder.createBlock(&taskOp.getRegion());
firOpBuilder.create<mlir::omp::TerminatorOp>(currentLocation);
firOpBuilder.setInsertionPointToStart(&taskOp.getRegion().front());
return true;
}

bool ClauseProcessor::processIf(
Expand Down
6 changes: 6 additions & 0 deletions flang/lib/Lower/OpenMP/ClauseProcessor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,12 @@ class ClauseProcessor {
bool processCopyprivate(mlir::Location currentLocation,
mlir::omp::CopyprivateClauseOps &result) const;
bool processDepend(mlir::omp::DependClauseOps &result) const;
// This is a special case of processDepend that processes the depend
// clause on Target ops - TargetOp, EnterDataOp, ExitDataOp, UpdateDataOp
// It sets up the generation of MLIR code for the target construct
// in question by first creating an enclosing omp.task operation and transfers
// the 'depend' clause and its arguments to this new omp.task operation.
bool processTargetDepend(mlir::Location currentLocation, mlir::omp::DependClauseOps &clauseOps) const;
bool
processEnter(llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const;
bool processIf(omp::clause::If::DirectiveNameModifier directiveName,
Expand Down
4 changes: 2 additions & 2 deletions flang/lib/Lower/OpenMP/OpenMP.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1140,7 +1140,7 @@ static void genTargetClauses(
llvm::SmallVectorImpl<mlir::Location> &devicePtrLocs,
llvm::SmallVectorImpl<mlir::Type> &devicePtrTypes) {
ClauseProcessor cp(converter, semaCtx, clauses);
cp.processDepend(clauseOps);
cp.processTargetDepend(loc, clauseOps);
cp.processDevice(stmtCtx, clauseOps);
cp.processHasDeviceAddr(clauseOps, deviceAddrTypes, deviceAddrLocs,
deviceAddrSyms);
Expand Down Expand Up @@ -1199,7 +1199,7 @@ static void genTargetEnterExitUpdateDataClauses(
mlir::Location loc, llvm::omp::Directive directive,
mlir::omp::TargetEnterExitUpdateDataClauseOps &clauseOps) {
ClauseProcessor cp(converter, semaCtx, clauses);
cp.processDepend(clauseOps);
cp.processTargetDepend(loc, clauseOps);
cp.processDevice(stmtCtx, clauseOps);
cp.processIf(directive, clauseOps);
cp.processNowait(clauseOps);
Expand Down
42 changes: 38 additions & 4 deletions flang/test/Lower/OpenMP/target.f90
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Original file line number Diff line number Diff line change
Expand Up @@ -27,9 +27,10 @@ subroutine omp_target_enter_depend
!$omp task depend(out: a)
call foo(a)
!$omp end task
!CHECK: omp.task if(%false) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!CHECK: %[[BOUNDS:.*]] = omp.map.bounds lower_bound({{.*}}) upper_bound({{.*}}) extent({{.*}}) stride({{.*}}) start_idx({{.*}})
!CHECK: %[[MAP:.*]] = omp.map.info var_ptr({{.*}}) map_clauses(to) capture(ByRef) bounds(%[[BOUNDS]]) -> !fir.ref<!fir.array<1024xi32>> {name = "a"}
!CHECK: omp.target_enter_data map_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>)
!CHECK: omp.target_enter_data map_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>)
!$omp target enter data map(to: a) depend(in: a)
return
end subroutine omp_target_enter_depend
Expand Down Expand Up @@ -166,9 +167,11 @@ subroutine omp_target_exit_depend
!$omp task depend(out: a)
call foo(a)
!$omp end task

!CHECK: omp.task if(%false) depend(taskdependout -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>)
!CHECK: %[[BOUNDS:.*]] = omp.map.bounds lower_bound({{.*}}) upper_bound({{.*}}) extent({{.*}}) stride({{.*}}) start_idx({{.*}})
!CHECK: %[[MAP:.*]] = omp.map.info var_ptr({{.*}}) map_clauses(from) capture(ByRef) bounds(%[[BOUNDS]]) -> !fir.ref<!fir.array<1024xi32>> {name = "a"}
!CHECK: omp.target_exit_data map_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>) depend(taskdependout -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>)
!CHECK: omp.target_exit_data map_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>)
!$omp target exit data map(from: a) depend(out: a)
end subroutine omp_target_exit_depend

Expand All @@ -187,9 +190,10 @@ subroutine omp_target_update_depend
call foo(a)
!$omp end task

!CHECK: omp.task if(%false) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!CHECK: %[[BOUNDS:.*]] = omp.map.bounds
!CHECK: %[[MAP:.*]] = omp.map.info var_ptr(%[[A]]#0 : !fir.ref<!fir.array<1024xi32>>, !fir.array<1024xi32>) map_clauses(to) capture(ByRef) bounds(%[[BOUNDS]]) -> !fir.ref<!fir.array<1024xi32>> {name = "a"}
!CHECK: omp.target_update motion_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>)
!CHECK: omp.target_update motion_entries(%[[MAP]] : !fir.ref<!fir.array<1024xi32>>)
!$omp target update to(a) depend(in:a)
end subroutine omp_target_update_depend

Expand Down Expand Up @@ -367,19 +371,49 @@ subroutine omp_target_depend
!$omp task depend(out: a)
call foo(a)
!$omp end task

!CHECK: omp.task if(%false) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!CHECK: %[[STRIDE_A:.*]] = arith.constant 1 : index
!CHECK: %[[LBOUND_A:.*]] = arith.constant 0 : index
!CHECK: %[[UBOUND_A:.*]] = arith.subi %c1024, %c1 : index
!CHECK: %[[BOUNDS_A:.*]] = omp.map.bounds lower_bound(%[[LBOUND_A]] : index) upper_bound(%[[UBOUND_A]] : index) extent(%[[EXTENT_A]] : index) stride(%[[STRIDE_A]] : index) start_idx(%[[STRIDE_A]] : index)
!CHECK: %[[MAP_A:.*]] = omp.map.info var_ptr(%[[A]]#0 : !fir.ref<!fir.array<1024xi32>>, !fir.array<1024xi32>) map_clauses(tofrom) capture(ByRef) bounds(%[[BOUNDS_A]]) -> !fir.ref<!fir.array<1024xi32>> {name = "a"}
!CHECK: omp.target map_entries(%[[MAP_A]] -> %[[BB0_ARG:.*]] : !fir.ref<!fir.array<1024xi32>>) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!CHECK: omp.target map_entries(%[[MAP_A]] -> %[[BB0_ARG:.*]] : !fir.ref<!fir.array<1024xi32>>)
!$omp target map(tofrom: a) depend(in: a)
a(1) = 10
!CHECK: omp.terminator
!$omp end target
!CHECK: }
end subroutine omp_target_depend

!===============================================================================
! Target with region `depend` clause and nowait
!===============================================================================

!CHECK-LABEL: func.func @_QPomp_target_depend_nowait() {
subroutine omp_target_depend_nowait
!CHECK: %[[EXTENT_A:.*]] = arith.constant 1024 : index
!CHECK: %[[A:.*]]:2 = hlfir.declare %{{.*}}(%{{.*}}) {uniq_name = "_QFomp_target_depend_nowaitEa"} : (!fir.ref<!fir.array<1024xi32>>, !fir.shape<1>) -> (!fir.ref<!fir.array<1024xi32>>, !fir.ref<!fir.array<1024xi32>>)
integer :: a(1024)
!CHECK: omp.task depend(taskdependout -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!$omp task depend(out: a)
call foo(a)
!$omp end task

!CHECK: omp.task if(%true) depend(taskdependin -> %[[A]]#1 : !fir.ref<!fir.array<1024xi32>>) {
!CHECK: %[[STRIDE_A:.*]] = arith.constant 1 : index
!CHECK: %[[LBOUND_A:.*]] = arith.constant 0 : index
!CHECK: %[[UBOUND_A:.*]] = arith.subi %c1024, %c1 : index
!CHECK: %[[BOUNDS_A:.*]] = omp.map.bounds lower_bound(%[[LBOUND_A]] : index) upper_bound(%[[UBOUND_A]] : index) extent(%[[EXTENT_A]] : index) stride(%[[STRIDE_A]] : index) start_idx(%[[STRIDE_A]] : index)
!CHECK: %[[MAP_A:.*]] = omp.map.info var_ptr(%[[A]]#0 : !fir.ref<!fir.array<1024xi32>>, !fir.array<1024xi32>) map_clauses(tofrom) capture(ByRef) bounds(%[[BOUNDS_A]]) -> !fir.ref<!fir.array<1024xi32>> {name = "a"}
!CHECK: omp.target nowait map_entries(%[[MAP_A]] -> %[[BB0_ARG:.*]] : !fir.ref<!fir.array<1024xi32>>)
!$omp target map(tofrom: a) depend(in: a) nowait
a(1) = 10
!CHECK: omp.terminator
!$omp end target
!CHECK: }
end subroutine omp_target_depend_nowait

!===============================================================================
! Target implicit capture
!===============================================================================
Expand Down
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