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[flang][cuda] Do not generate data transfer within cuf kernel #89973

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Merged
merged 1 commit into from
Apr 25, 2024
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[flang][cuda] Do not generate data transfer within cuf kernel #89973

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8 changes: 5 additions & 3 deletions flang/lib/Lower/Bridge.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3810,12 +3810,14 @@ class FirConverter : public Fortran::lower::AbstractConverter {
mlir::Location loc = getCurrentLocation();
fir::FirOpBuilder &builder = getFirOpBuilder();

bool isInDeviceContext =
builder.getRegion().getParentOfType<fir::CUDAKernelOp>();
bool isCUDATransfer = Fortran::evaluate::HasCUDAAttrs(assign.lhs) ||
Fortran::evaluate::HasCUDAAttrs(assign.rhs);
bool hasCUDAImplicitTransfer =
Fortran::evaluate::HasCUDAImplicitTransfer(assign.rhs);
llvm::SmallVector<mlir::Value> implicitTemps;
if (hasCUDAImplicitTransfer)
if (hasCUDAImplicitTransfer && !isInDeviceContext)
implicitTemps = genCUDAImplicitDataTransfer(builder, loc, assign);

// Gather some information about the assignment that will impact how it is
Expand Down Expand Up @@ -3874,13 +3876,13 @@ class FirConverter : public Fortran::lower::AbstractConverter {
Fortran::lower::StatementContext localStmtCtx;
hlfir::Entity rhs = evaluateRhs(localStmtCtx);
hlfir::Entity lhs = evaluateLhs(localStmtCtx);
if (isCUDATransfer && !hasCUDAImplicitTransfer)
if (isCUDATransfer && !hasCUDAImplicitTransfer && !isInDeviceContext)
genCUDADataTransfer(builder, loc, assign, lhs, rhs);
else
builder.create<hlfir::AssignOp>(loc, rhs, lhs,
isWholeAllocatableAssignment,
keepLhsLengthInAllocatableAssignment);
if (hasCUDAImplicitTransfer) {
if (hasCUDAImplicitTransfer && !isInDeviceContext) {
localSymbols.popScope();
for (mlir::Value temp : implicitTemps)
builder.create<fir::FreeMemOp>(loc, temp);
Expand Down
22 changes: 22 additions & 0 deletions flang/test/Lower/CUDA/cuda-data-transfer.cuf
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Expand Up @@ -119,3 +119,25 @@ end
! CHECK: %[[T:.*]]:2 = hlfir.declare %7 {cuda_attr = #fir.cuda<device>, uniq_name = "_QFsub3Et"} : (!fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>) -> (!fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>, !fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>)
! CHECK: %[[TMP_DECL:.*]]:2 = hlfir.declare %0 {uniq_name = ".tmp"} : (!fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>) -> (!fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>, !fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>)
! CHECK: fir.cuda_data_transfer %[[T]]#1 to %[[TMP_DECL]]#0 {transfer_kind = #fir.cuda_transfer<device_host>} : !fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>, !fir.ref<!fir.type<_QMmod1Tt1{i:i32}>>


! Check that fir.cuda_data_transfer are not generated within cuf kernel
subroutine sub4()
integer, parameter :: n = 10
real, device :: adev(n)
real :: ahost(n)
real :: b
integer :: i

adev = ahost
!$cuf kernel do <<<*,*>>>
do i = 1, n
adev(i) = adev(i) + b
enddo
end subroutine

! CHECK-LABEL: func.func @_QPsub4()
! CHECK: fir.cuda_data_transfer
! CHECK: fir.cuda_kernel<<<*, *>>>
! CHECK-NOT: fir.cuda_data_transfer
! CHECK: hlfir.assign