https://github.com/DominikAdamski updated
https://github.com/llvm/llvm-project/pull/155818
>From efdd979d6189b986ea09dec7c0c0da26725ab1a1 Mon Sep 17 00:00:00 2001
From: Dominik Adamski <dominik.adam...@amd.com>
Date: Wed, 27 Aug 2025 10:24:51 -0500
Subject: [PATCH 1/3] [Flang][OpenMP] Enable no-loop kernels
Enable the generation of no-loop kernels for Fortran OpenMP code.
target teams distribute parallel do pragmas can be promoted to no-loop
kernels if the user adds the -fopenmp-assume-teams-oversubscription
and -fopenmp-assume-threads-oversubscription flags.
If the OpenMP kernel contains reduction or num_teams clauses,
it is not promoted to no-loop mode.
The global OpenMP device RTL oversubscription flags
no longer force no-loop code generation for Fortran.
---
clang/include/clang/Driver/Options.td | 21 +++++++--
.../llvm/Frontend/OpenMP/OMPIRBuilder.h | 8 +++-
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 21 +++++----
.../mlir/Dialect/OpenMP/OpenMPEnums.td | 4 +-
mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp | 41 +++++++++++++++---
.../OpenMP/OpenMPToLLVMIRTranslation.cpp | 22 +++++++++-
offload/DeviceRTL/src/Workshare.cpp | 13 ------
.../offloading/fortran/target-no-loop.f90 | 43 +++++++++++++++++++
8 files changed, 136 insertions(+), 37 deletions(-)
create mode 100644 offload/test/offloading/fortran/target-no-loop.f90
diff --git a/clang/include/clang/Driver/Options.td
b/clang/include/clang/Driver/Options.td
index b1ae3cf6525b8..4c078a45628a9 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3824,10 +3824,23 @@ let Visibility = [ClangOption, CC1Option, FC1Option,
FlangOption] in {
let Group = f_Group in {
def fopenmp_target_debug_EQ : Joined<["-"], "fopenmp-target-debug=">;
-def fopenmp_assume_teams_oversubscription : Flag<["-"],
"fopenmp-assume-teams-oversubscription">;
-def fopenmp_assume_threads_oversubscription : Flag<["-"],
"fopenmp-assume-threads-oversubscription">;
-def fno_openmp_assume_teams_oversubscription : Flag<["-"],
"fno-openmp-assume-teams-oversubscription">;
-def fno_openmp_assume_threads_oversubscription : Flag<["-"],
"fno-openmp-assume-threads-oversubscription">;
+def fopenmp_assume_teams_oversubscription : Flag<["-"],
"fopenmp-assume-teams-oversubscription">,
+ HelpText<"Allow enforcement to ensure there are enough teams to cover the "
+ "loop iteration space. It may ignore environment variables. "
+ "If the fopenmp-assume-teams-oversubscription and "
+ "fopenmp-assume-threads-oversubscription flags are set, Flang may "
+ "generate more optimized OpenMP kernels for target teams distribute
"
+ "parallel do pragmas.">;
+def fopenmp_assume_threads_oversubscription : Flag<["-"],
"fopenmp-assume-threads-oversubscription">,
+ HelpText<"Assume threads oversubscription. If the "
+ "fopenmp-assume-teams-oversubscription and "
+ "fopenmp-assume-threads-oversubscription flags are set, Flang may "
+ "generate more optimized OpenMP kernels for target teams distribute
"
+ "parallel do pragmas.">;
+def fno_openmp_assume_teams_oversubscription : Flag<["-"],
"fno-openmp-assume-teams-oversubscription">,
+ HelpText<"Do not assume teams oversubscription.">;
+def fno_openmp_assume_threads_oversubscription : Flag<["-"],
"fno-openmp-assume-threads-oversubscription">,
+ HelpText<"Do not assume threads oversubscription.">;
def fopenmp_assume_no_thread_state : Flag<["-"],
"fopenmp-assume-no-thread-state">,
HelpText<"Assert no thread in a parallel region modifies an ICV">,
MarshallingInfoFlag<LangOpts<"OpenMPNoThreadState">>;
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
index 1050e3d8b08dd..49078e4162ebc 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
@@ -1075,11 +1075,13 @@ class OpenMPIRBuilder {
/// preheader of the loop.
/// \param LoopType Information about type of loop worksharing.
/// It corresponds to type of loop workshare OpenMP pragma.
+ /// \param NoLoop If true, no-loop code is generated.
///
/// \returns Point where to insert code after the workshare construct.
InsertPointTy applyWorkshareLoopTarget(DebugLoc DL, CanonicalLoopInfo *CLI,
InsertPointTy AllocaIP,
- omp::WorksharingLoopType LoopType);
+ omp::WorksharingLoopType LoopType,
+ bool NoLoop);
/// Modifies the canonical loop to be a statically-scheduled workshare loop.
///
@@ -1199,6 +1201,7 @@ class OpenMPIRBuilder {
/// present.
/// \param LoopType Information about type of loop worksharing.
/// It corresponds to type of loop workshare OpenMP pragma.
+ /// \param NoLoop If true, no-loop code is generated.
///
/// \returns Point where to insert code after the workshare construct.
LLVM_ABI InsertPointOrErrorTy applyWorkshareLoop(
@@ -1209,7 +1212,8 @@ class OpenMPIRBuilder {
bool HasMonotonicModifier = false, bool HasNonmonotonicModifier = false,
bool HasOrderedClause = false,
omp::WorksharingLoopType LoopType =
- omp::WorksharingLoopType::ForStaticLoop);
+ omp::WorksharingLoopType::ForStaticLoop,
+ bool NoLoop = false);
/// Tile a loop nest.
///
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index c0e956840f989..bec5abb45041f 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -4955,7 +4955,7 @@ static void createTargetLoopWorkshareCall(OpenMPIRBuilder
*OMPBuilder,
WorksharingLoopType LoopType,
BasicBlock *InsertBlock, Value
*Ident,
Value *LoopBodyArg, Value *TripCount,
- Function &LoopBodyFn) {
+ Function &LoopBodyFn, bool NoLoop) {
Type *TripCountTy = TripCount->getType();
Module &M = OMPBuilder->M;
IRBuilder<> &Builder = OMPBuilder->Builder;
@@ -4984,7 +4984,7 @@ static void createTargetLoopWorkshareCall(OpenMPIRBuilder
*OMPBuilder,
if (LoopType == WorksharingLoopType::DistributeForStaticLoop) {
RealArgs.push_back(ConstantInt::get(TripCountTy, 0));
}
- RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), 0));
+ RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), NoLoop));
Builder.CreateCall(RTLFn, RealArgs);
}
@@ -4992,7 +4992,7 @@ static void createTargetLoopWorkshareCall(OpenMPIRBuilder
*OMPBuilder,
static void workshareLoopTargetCallback(
OpenMPIRBuilder *OMPIRBuilder, CanonicalLoopInfo *CLI, Value *Ident,
Function &OutlinedFn, const SmallVector<Instruction *, 4> &ToBeDeleted,
- WorksharingLoopType LoopType) {
+ WorksharingLoopType LoopType, bool NoLoop) {
IRBuilder<> &Builder = OMPIRBuilder->Builder;
BasicBlock *Preheader = CLI->getPreheader();
Value *TripCount = CLI->getTripCount();
@@ -5039,17 +5039,16 @@ static void workshareLoopTargetCallback(
OutlinedFnCallInstruction->eraseFromParent();
createTargetLoopWorkshareCall(OMPIRBuilder, LoopType, Preheader, Ident,
- LoopBodyArg, TripCount, OutlinedFn);
+ LoopBodyArg, TripCount, OutlinedFn, NoLoop);
for (auto &ToBeDeletedItem : ToBeDeleted)
ToBeDeletedItem->eraseFromParent();
CLI->invalidate();
}
-OpenMPIRBuilder::InsertPointTy
-OpenMPIRBuilder::applyWorkshareLoopTarget(DebugLoc DL, CanonicalLoopInfo *CLI,
- InsertPointTy AllocaIP,
- WorksharingLoopType LoopType) {
+OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::applyWorkshareLoopTarget(
+ DebugLoc DL, CanonicalLoopInfo *CLI, InsertPointTy AllocaIP,
+ WorksharingLoopType LoopType, bool NoLoop) {
uint32_t SrcLocStrSize;
Constant *SrcLocStr = getOrCreateSrcLocStr(DL, SrcLocStrSize);
Value *Ident = getOrCreateIdent(SrcLocStr, SrcLocStrSize);
@@ -5132,7 +5131,7 @@ OpenMPIRBuilder::applyWorkshareLoopTarget(DebugLoc DL,
CanonicalLoopInfo *CLI,
OI.PostOutlineCB = [=, ToBeDeletedVec =
std::move(ToBeDeleted)](Function &OutlinedFn) {
workshareLoopTargetCallback(this, CLI, Ident, OutlinedFn, ToBeDeletedVec,
- LoopType);
+ LoopType, NoLoop);
};
addOutlineInfo(std::move(OI));
return CLI->getAfterIP();
@@ -5143,9 +5142,9 @@ OpenMPIRBuilder::InsertPointOrErrorTy
OpenMPIRBuilder::applyWorkshareLoop(
bool NeedsBarrier, omp::ScheduleKind SchedKind, Value *ChunkSize,
bool HasSimdModifier, bool HasMonotonicModifier,
bool HasNonmonotonicModifier, bool HasOrderedClause,
- WorksharingLoopType LoopType) {
+ WorksharingLoopType LoopType, bool NoLoop) {
if (Config.isTargetDevice())
- return applyWorkshareLoopTarget(DL, CLI, AllocaIP, LoopType);
+ return applyWorkshareLoopTarget(DL, CLI, AllocaIP, LoopType, NoLoop);
OMPScheduleType EffectiveScheduleType = computeOpenMPScheduleType(
SchedKind, ChunkSize, HasSimdModifier, HasMonotonicModifier,
HasNonmonotonicModifier, HasOrderedClause);
diff --git a/mlir/include/mlir/Dialect/OpenMP/OpenMPEnums.td
b/mlir/include/mlir/Dialect/OpenMP/OpenMPEnums.td
index c080c3fac87d4..e0cd06805ab40 100644
--- a/mlir/include/mlir/Dialect/OpenMP/OpenMPEnums.td
+++ b/mlir/include/mlir/Dialect/OpenMP/OpenMPEnums.td
@@ -230,6 +230,7 @@ def TargetRegionFlagsNone : I32BitEnumAttrCaseNone<"none">;
def TargetRegionFlagsGeneric : I32BitEnumAttrCaseBit<"generic", 0>;
def TargetRegionFlagsSpmd : I32BitEnumAttrCaseBit<"spmd", 1>;
def TargetRegionFlagsTripCount : I32BitEnumAttrCaseBit<"trip_count", 2>;
+def TargetRegionFlagsNoLoop : I32BitEnumAttrCaseBit<"no_loop", 3>;
def TargetRegionFlags : OpenMP_BitEnumAttr<
"TargetRegionFlags",
@@ -237,7 +238,8 @@ def TargetRegionFlags : OpenMP_BitEnumAttr<
TargetRegionFlagsNone,
TargetRegionFlagsGeneric,
TargetRegionFlagsSpmd,
- TargetRegionFlagsTripCount
+ TargetRegionFlagsTripCount,
+ TargetRegionFlagsNoLoop
]>;
//===----------------------------------------------------------------------===//
diff --git a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
index 6e43f28e8d93d..1e10dd114b30a 100644
--- a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
+++ b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
@@ -2106,6 +2106,29 @@ Operation *TargetOp::getInnermostCapturedOmpOp() {
});
}
+/// Check if we can promote SPMD kernel to No-Loop kernel
+static bool canPromoteToNoLoop(Operation *capturedOp, TeamsOp teamsOp,
+ WsloopOp *wsLoopOp) {
+ // num_teams clause can break no-loop teams/threads assumption
+ if (teamsOp.getNumTeamsUpper())
+ return false;
+ // reduction kernels are slower in no-loop mode
+ if (teamsOp.getNumReductionVars())
+ return false;
+ if (wsLoopOp->getNumReductionVars())
+ return false;
+ // check if the user allows the promotion of kernels to no-loop mode
+ OffloadModuleInterface offloadMod =
+ capturedOp->getParentOfType<omp::OffloadModuleInterface>();
+ if (!offloadMod)
+ return false;
+ auto ompFlags = offloadMod.getFlags();
+ if (!ompFlags)
+ return false;
+ return ompFlags.getAssumeTeamsOversubscription() &&
+ ompFlags.getAssumeThreadsOversubscription();
+}
+
TargetRegionFlags TargetOp::getKernelExecFlags(Operation *capturedOp) {
// A non-null captured op is only valid if it resides inside of a TargetOp
// and is the result of calling getInnermostCapturedOmpOp() on it.
@@ -2134,7 +2157,8 @@ TargetRegionFlags TargetOp::getKernelExecFlags(Operation
*capturedOp) {
// Detect target-teams-distribute-parallel-wsloop[-simd].
if (numWrappers == 2) {
- if (!isa<WsloopOp>(innermostWrapper))
+ WsloopOp *wsloopOp = dyn_cast<WsloopOp>(innermostWrapper);
+ if (!wsloopOp)
return TargetRegionFlags::generic;
innermostWrapper = std::next(innermostWrapper);
@@ -2145,12 +2169,19 @@ TargetRegionFlags
TargetOp::getKernelExecFlags(Operation *capturedOp) {
if (!isa_and_present<ParallelOp>(parallelOp))
return TargetRegionFlags::generic;
- Operation *teamsOp = parallelOp->getParentOp();
- if (!isa_and_present<TeamsOp>(teamsOp))
+ TeamsOp teamsOp = dyn_cast<TeamsOp>(parallelOp->getParentOp());
+ if (!teamsOp)
return TargetRegionFlags::generic;
- if (teamsOp->getParentOp() == targetOp.getOperation())
- return TargetRegionFlags::spmd | TargetRegionFlags::trip_count;
+ TargetRegionFlags result;
+
+ if (teamsOp->getParentOp() == targetOp.getOperation()) {
+ TargetRegionFlags result =
+ TargetRegionFlags::spmd | TargetRegionFlags::trip_count;
+ if (canPromoteToNoLoop(capturedOp, teamsOp, wsloopOp))
+ result = result | TargetRegionFlags::no_loop;
+ return result;
+ }
}
// Detect target-teams-distribute[-simd] and target-teams-loop.
else if (isa<DistributeOp, LoopOp>(innermostWrapper)) {
diff --git
a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 6694de8383534..d67d5eb741543 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -2590,13 +2590,27 @@ convertOmpWsloop(Operation &opInst, llvm::IRBuilderBase
&builder,
}
builder.SetInsertPoint(*regionBlock, (*regionBlock)->begin());
+
+ bool noLoopMode = false;
+ omp::TargetOp targetOp = wsloopOp->getParentOfType<mlir::omp::TargetOp>();
+ if (targetOp) {
+ Operation *targetCapturedOp = targetOp.getInnermostCapturedOmpOp();
+ omp::TargetRegionFlags kernelFlags =
+ targetOp.getKernelExecFlags(targetCapturedOp);
+ if (omp::bitEnumContainsAll(kernelFlags,
+ omp::TargetRegionFlags::spmd |
+ omp::TargetRegionFlags::no_loop) &&
+ !omp::bitEnumContainsAny(kernelFlags, omp::TargetRegionFlags::generic))
+ noLoopMode = true;
+ }
+
llvm::OpenMPIRBuilder::InsertPointOrErrorTy wsloopIP =
ompBuilder->applyWorkshareLoop(
ompLoc.DL, loopInfo, allocaIP, loopNeedsBarrier,
convertToScheduleKind(schedule), chunk, isSimd,
scheduleMod == omp::ScheduleModifier::monotonic,
scheduleMod == omp::ScheduleModifier::nonmonotonic, isOrdered,
- workshareLoopType);
+ workshareLoopType, noLoopMode);
if (failed(handleError(wsloopIP, opInst)))
return failure();
@@ -5365,6 +5379,12 @@ initTargetDefaultAttrs(omp::TargetOp targetOp, Operation
*capturedOp,
? llvm::omp::OMP_TGT_EXEC_MODE_GENERIC_SPMD
: llvm::omp::OMP_TGT_EXEC_MODE_GENERIC
: llvm::omp::OMP_TGT_EXEC_MODE_SPMD;
+ if (omp::bitEnumContainsAll(kernelFlags,
+ omp::TargetRegionFlags::spmd |
+ omp::TargetRegionFlags::no_loop) &&
+ !omp::bitEnumContainsAny(kernelFlags, omp::TargetRegionFlags::generic))
+ attrs.ExecFlags = llvm::omp::OMP_TGT_EXEC_MODE_SPMD_NO_LOOP;
+
attrs.MinTeams = minTeamsVal;
attrs.MaxTeams.front() = maxTeamsVal;
attrs.MinThreads = 1;
diff --git a/offload/DeviceRTL/src/Workshare.cpp
b/offload/DeviceRTL/src/Workshare.cpp
index 59a2cc3f27aca..653104ce883d1 100644
--- a/offload/DeviceRTL/src/Workshare.cpp
+++ b/offload/DeviceRTL/src/Workshare.cpp
@@ -800,10 +800,6 @@ template <typename Ty> class StaticLoopChunker {
// If we know we have more threads than iterations we can indicate that to
// avoid an outer loop.
- if (config::getAssumeThreadsOversubscription()) {
- OneIterationPerThread = true;
- }
-
if (OneIterationPerThread)
ASSERT(NumThreads >= NumIters, "Broken assumption");
@@ -851,10 +847,6 @@ template <typename Ty> class StaticLoopChunker {
// If we know we have more blocks than iterations we can indicate that to
// avoid an outer loop.
- if (config::getAssumeTeamsOversubscription()) {
- OneIterationPerThread = true;
- }
-
if (OneIterationPerThread)
ASSERT(NumBlocks >= NumIters, "Broken assumption");
@@ -914,11 +906,6 @@ template <typename Ty> class StaticLoopChunker {
// If we know we have more threads (across all blocks) than iterations we
// can indicate that to avoid an outer loop.
- if (config::getAssumeTeamsOversubscription() &
- config::getAssumeThreadsOversubscription()) {
- OneIterationPerThread = true;
- }
-
if (OneIterationPerThread)
ASSERT(NumBlocks * NumThreads >= NumIters, "Broken assumption");
diff --git a/offload/test/offloading/fortran/target-no-loop.f90
b/offload/test/offloading/fortran/target-no-loop.f90
new file mode 100644
index 0000000000000..dd2bf7c2196b6
--- /dev/null
+++ b/offload/test/offloading/fortran/target-no-loop.f90
@@ -0,0 +1,43 @@
+! Check if the first OpenMP GPU kernel is promoted to no-loop mode.
+! The second cannot be promoted due to the limit on the number of teams.
+! REQUIRES: flang, amdgpu
+
+! RUN: %libomptarget-compile-fortran-generic -O3
-fopenmp-assume-threads-oversubscription -fopenmp-assume-teams-oversubscription
+! RUN: env LIBOMPTARGET_INFO=16 %libomptarget-run-generic 2>&1 |
%fcheck-generic
+program main
+ use omp_lib
+ implicit none
+ integer :: i
+ integer :: array(1024), errors = 0
+ array = 1
+
+ !$omp target teams distribute parallel do
+ do i = 1, 1024
+ array(i) = i
+ end do
+
+ do i = 1, 1024
+ if ( array( i) .ne. (i) ) then
+ errors = errors + 1
+ end if
+ end do
+
+ !$omp target teams distribute parallel do num_teams(3)
+ do i = 1, 1024
+ array(i) = i
+ end do
+
+ do i = 1, 1024
+ if ( array( i) .ne. (i) ) then
+ errors = errors + 1
+ end if
+ end do
+
+ print *,"number of errors: ", errors
+
+end program main
+
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD-No-Loop mode
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD mode
+! CHECK: number of errors: 0
+
>From 564410d9930b9b838d4dadfbea566c222c265e87 Mon Sep 17 00:00:00 2001
From: Dominik Adamski <dominik.adam...@amd.com>
Date: Mon, 1 Sep 2025 04:50:10 -0500
Subject: [PATCH 2/3] Applied remarks
---
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 4 +-
mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp | 8 +-
.../offloading/fortran/target-no-loop.f90 | 77 ++++++++++++++++---
3 files changed, 72 insertions(+), 17 deletions(-)
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index bec5abb45041f..9ec2057bbee13 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -4983,8 +4983,10 @@ static void
createTargetLoopWorkshareCall(OpenMPIRBuilder *OMPBuilder,
RealArgs.push_back(ConstantInt::get(TripCountTy, 0));
if (LoopType == WorksharingLoopType::DistributeForStaticLoop) {
RealArgs.push_back(ConstantInt::get(TripCountTy, 0));
+ RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), NoLoop));
}
- RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), NoLoop));
+ else
+ RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), 0));
Builder.CreateCall(RTLFn, RealArgs);
}
diff --git a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
index 1e10dd114b30a..0371bc2e449f2 100644
--- a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
+++ b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
@@ -2106,18 +2106,18 @@ Operation *TargetOp::getInnermostCapturedOmpOp() {
});
}
-/// Check if we can promote SPMD kernel to No-Loop kernel
+/// Check if we can promote SPMD kernel to No-Loop kernel.
static bool canPromoteToNoLoop(Operation *capturedOp, TeamsOp teamsOp,
WsloopOp *wsLoopOp) {
- // num_teams clause can break no-loop teams/threads assumption
+ // num_teams clause can break no-loop teams/threads assumption.
if (teamsOp.getNumTeamsUpper())
return false;
- // reduction kernels are slower in no-loop mode
+ // Reduction kernels are slower in no-loop mode.
if (teamsOp.getNumReductionVars())
return false;
if (wsLoopOp->getNumReductionVars())
return false;
- // check if the user allows the promotion of kernels to no-loop mode
+ // Check if the user allows the promotion of kernels to no-loop mode.
OffloadModuleInterface offloadMod =
capturedOp->getParentOfType<omp::OffloadModuleInterface>();
if (!offloadMod)
diff --git a/offload/test/offloading/fortran/target-no-loop.f90
b/offload/test/offloading/fortran/target-no-loop.f90
index dd2bf7c2196b6..6251aca471561 100644
--- a/offload/test/offloading/fortran/target-no-loop.f90
+++ b/offload/test/offloading/fortran/target-no-loop.f90
@@ -1,43 +1,96 @@
-! Check if the first OpenMP GPU kernel is promoted to no-loop mode.
-! The second cannot be promoted due to the limit on the number of teams.
! REQUIRES: flang, amdgpu
! RUN: %libomptarget-compile-fortran-generic -O3
-fopenmp-assume-threads-oversubscription -fopenmp-assume-teams-oversubscription
-! RUN: env LIBOMPTARGET_INFO=16 %libomptarget-run-generic 2>&1 |
%fcheck-generic
+! RUN: env LIBOMPTARGET_INFO=16 OMP_NUM_TEAMS=16 OMP_TEAMS_THREAD_LIMIT=16
%libomptarget-run-generic 2>&1 | %fcheck-generic
+function check_errors(array) result (errors)
+ integer, intent(in) :: array(1024)
+ integer :: errors
+ integer :: i
+ errors = 0
+ do i = 1, 1024
+ if ( array( i) .ne. (i) ) then
+ errors = errors + 1
+ end if
+ end do
+end function
+
program main
use omp_lib
implicit none
- integer :: i
+ integer :: i,j,red
integer :: array(1024), errors = 0
array = 1
+ ! No-loop kernel
!$omp target teams distribute parallel do
do i = 1, 1024
array(i) = i
- end do
+ end do
+ errors = errors + check_errors(array)
+ ! SPMD kernel (num_teams clause blocks promotion to no-loop)
+ array = 1
+ !$omp target teams distribute parallel do num_teams(3)
do i = 1, 1024
- if ( array( i) .ne. (i) ) then
- errors = errors + 1
- end if
+ array(i) = i
end do
- !$omp target teams distribute parallel do num_teams(3)
+ errors = errors + check_errors(array)
+
+ ! No-loop kernel
+ array = 1
+ !$omp target teams distribute parallel do num_threads(64)
do i = 1, 1024
array(i) = i
end do
+ errors = errors + check_errors(array)
+
+ ! SPMD kernel
+ array = 1
+ !$omp target parallel do
do i = 1, 1024
- if ( array( i) .ne. (i) ) then
- errors = errors + 1
- end if
+ array(i) = i
+ end do
+
+ errors = errors + check_errors(array)
+
+ ! Generic kernel
+ array = 1
+ !$omp target teams distribute
+ do i = 1, 1024
+ array(i) = i
+ end do
+
+ errors = errors + check_errors(array)
+
+ ! SPMD kernel (reduction clause blocks promotion to no-loop)
+ array = 1
+ red =0
+ !$omp target teams distribute parallel do reduction(+:red)
+ do i = 1, 1024
+ red = red + array(i)
end do
+ if (red .ne. 1024) then
+ errors = errors + 1
+ end if
+
print *,"number of errors: ", errors
end program main
! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD-No-Loop mode
+! CHECK: info: #Args: 3 Teams x Thrds: 64x 16
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD mode
+! CHECK: info: #Args: 3 Teams x Thrds: 3x 16 {{.*}}
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD-No-Loop mode
+! CHECK: info: #Args: 3 Teams x Thrds: 64x 16 {{.*}}
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD mode
+! CHECK: info: #Args: 3 Teams x Thrds: 1x 16
+! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
Generic mode
+! CHECK: info: #Args: 3 Teams x Thrds: 16x 16 {{.*}}
! CHECK: "PluginInterface" device {{[0-9]+}} info: Launching kernel {{.*}}
SPMD mode
+! CHECK: info: #Args: 4 Teams x Thrds: 16x 16 {{.*}}
! CHECK: number of errors: 0
>From 8efb5e061af1a16d636d9ed62600bd12b117c5dd Mon Sep 17 00:00:00 2001
From: Dominik Adamski <dominik.adam...@amd.com>
Date: Tue, 2 Sep 2025 05:15:53 -0500
Subject: [PATCH 3/3] Fix format
---
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index 9ec2057bbee13..aabac59c29b37 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -4984,8 +4984,7 @@ static void createTargetLoopWorkshareCall(OpenMPIRBuilder
*OMPBuilder,
if (LoopType == WorksharingLoopType::DistributeForStaticLoop) {
RealArgs.push_back(ConstantInt::get(TripCountTy, 0));
RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), NoLoop));
- }
- else
+ } else
RealArgs.push_back(ConstantInt::get(Builder.getInt8Ty(), 0));
Builder.CreateCall(RTLFn, RealArgs);
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