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[Flang][OpenMP] Implement "promotion" of use_device_ptr non-cptr arguments to use_device_addr (#82834)
This effectively implements some now deprecated OpenMP functionality that some applications (most notably at the moment GenASiS) unfortunately depend on (deprecated in specification version 5.2): "If a list item in a use_device_ptr clause is not of type C_PTR, the behavior is as if the list item appeared in a use_device_addr clause. Support for such list items in a use_device_ptr clause is deprecated." This PR downgrades the hard-error to a deprecated warning and "promotes" the above cases by simply moving the offending operands from the use_device_ptr value list to the back of the use_device_addr list (and moves the related symbols, locs and types that form the BlockArgs correspondingly) and then the generation of the target data construct proceeds as normal.
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‎flang/lib/Lower/OpenMP/OpenMP.cpp

Lines changed: 66 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -798,6 +798,58 @@ genTaskGroupOp(Fortran::lower::AbstractConverter &converter,
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/*task_reductions=*/nullptr, allocateOperands, allocatorOperands);
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}
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// This helper function implements the functionality of "promoting"
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// non-CPTR arguments of use_device_ptr to use_device_addr
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// arguments (automagic conversion of use_device_ptr ->
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// use_device_addr in these cases). The way we do so currently is
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// through the shuffling of operands from the devicePtrOperands to
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// deviceAddrOperands where neccesary and re-organizing the types,
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// locations and symbols to maintain the correct ordering of ptr/addr
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// input -> BlockArg.
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//
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// This effectively implements some deprecated OpenMP functionality
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// that some legacy applications unfortunately depend on
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// (deprecated in specification version 5.2):
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//
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// "If a list item in a use_device_ptr clause is not of type C_PTR,
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// the behavior is as if the list item appeared in a use_device_addr
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// clause. Support for such list items in a use_device_ptr clause
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// is deprecated."
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static void promoteNonCPtrUseDevicePtrArgsToUseDeviceAddr(
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llvm::SmallVector<mlir::Value> &devicePtrOperands,
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llvm::SmallVector<mlir::Value> &deviceAddrOperands,
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llvm::SmallVector<mlir::Type> &useDeviceTypes,
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llvm::SmallVector<mlir::Location> &useDeviceLocs,
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llvm::SmallVector<const Fortran::semantics::Symbol *> &useDeviceSymbols) {
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auto moveElementToBack = [](size_t idx, auto &vector) {
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auto *iter = std::next(vector.begin(), idx);
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vector.push_back(*iter);
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vector.erase(iter);
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};
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// Iterate over our use_device_ptr list and shift all non-cptr arguments into
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// use_device_addr.
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for (auto *it = devicePtrOperands.begin(); it != devicePtrOperands.end();) {
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if (!fir::isa_builtin_cptr_type(fir::unwrapRefType(it->getType()))) {
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deviceAddrOperands.push_back(*it);
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// We have to shuffle the symbols around as well, to maintain
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// the correct Input -> BlockArg for use_device_ptr/use_device_addr.
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// NOTE: However, as map's do not seem to be included currently
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// this isn't as pertinent, but we must try to maintain for
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// future alterations. I believe the reason they are not currently
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// is that the BlockArg assign/lowering needs to be extended
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// to a greater set of types.
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auto idx = std::distance(devicePtrOperands.begin(), it);
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moveElementToBack(idx, useDeviceTypes);
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moveElementToBack(idx, useDeviceLocs);
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moveElementToBack(idx, useDeviceSymbols);
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it = devicePtrOperands.erase(it);
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continue;
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}
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++it;
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}
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}
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static mlir::omp::DataOp
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genDataOp(Fortran::lower::AbstractConverter &converter,
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Fortran::semantics::SemanticsContext &semaCtx,
@@ -820,6 +872,20 @@ genDataOp(Fortran::lower::AbstractConverter &converter,
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useDeviceSymbols);
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cp.processUseDeviceAddr(deviceAddrOperands, useDeviceTypes, useDeviceLocs,
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useDeviceSymbols);
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// This function implements the deprecated functionality of use_device_ptr
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// that allows users to provide non-CPTR arguments to it with the caveat
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// that the compiler will treat them as use_device_addr. A lot of legacy
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// code may still depend on this functionality, so we should support it
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// in some manner. We do so currently by simply shifting non-cptr operands
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// from the use_device_ptr list into the front of the use_device_addr list
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// whilst maintaining the ordering of useDeviceLocs, useDeviceSymbols and
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// useDeviceTypes to use_device_ptr/use_device_addr input for BlockArg
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// ordering.
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// TODO: Perhaps create a user provideable compiler option that will
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// re-introduce a hard-error rather than a warning in these cases.
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promoteNonCPtrUseDevicePtrArgsToUseDeviceAddr(
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devicePtrOperands, deviceAddrOperands, useDeviceTypes, useDeviceLocs,
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useDeviceSymbols);
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cp.processMap(currentLocation, llvm::omp::Directive::OMPD_target_data,
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stmtCtx, mapOperands);
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‎flang/lib/Semantics/check-omp-structure.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2948,7 +2948,7 @@ void OmpStructureChecker::Enter(const parser::OmpClause::UseDevicePtr &x) {
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if (name->symbol) {
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if (!(IsBuiltinCPtr(*(name->symbol)))) {
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context_.Say(itr->second->source,
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"'%s' in USE_DEVICE_PTR clause must be of type C_PTR"_err_en_US,
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"Use of non-C_PTR type '%s' in USE_DEVICE_PTR is deprecated, use USE_DEVICE_ADDR instead"_warn_en_US,
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name->ToString());
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} else {
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useDevicePtrNameList.push_back(*name);

‎flang/test/Lower/OpenMP/use-device-ptr-to-use-device-addr.f90

Lines changed: 72 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,72 @@
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!RUN: %flang_fc1 -emit-hlfir -fopenmp %s -o - | FileCheck %s
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!RUN: bbc -emit-hlfir -fopenmp %s -o - | FileCheck %s
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! This tests primary goal is to check the promotion of
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! non-CPTR arguments from use_device_ptr to
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! use_device_addr works, without breaking any
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! functionality
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!CHECK: func.func @{{.*}}only_use_device_ptr()
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!CHECK: omp.target_data use_device_ptr(%{{.*}} : !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>) use_device_addr(%{{.*}}, %{{.*}} : !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>) {
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!CHECK: ^bb0(%{{.*}}: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>):
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subroutine only_use_device_ptr
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use iso_c_binding
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integer, pointer, dimension(:) :: array
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real, pointer :: pa(:)
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type(c_ptr) :: cptr
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!$omp target data use_device_ptr(pa, cptr, array)
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!$omp end target data
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end subroutine
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!CHECK: func.func @{{.*}}mix_use_device_ptr_and_addr()
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!CHECK: omp.target_data use_device_ptr({{.*}} : !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>) use_device_addr(%{{.*}}, %{{.*}} : !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>) {
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!CHECK: ^bb0(%{{.*}}: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>):
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subroutine mix_use_device_ptr_and_addr
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use iso_c_binding
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integer, pointer, dimension(:) :: array
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real, pointer :: pa(:)
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type(c_ptr) :: cptr
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!$omp target data use_device_ptr(pa, cptr) use_device_addr(array)
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!$omp end target data
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end subroutine
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!CHECK: func.func @{{.*}}only_use_device_addr()
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!CHECK: omp.target_data use_device_addr(%{{.*}}, %{{.*}}, %{{.*}} : !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>) {
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!CHECK: ^bb0(%{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, %{{.*}}: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>):
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subroutine only_use_device_addr
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use iso_c_binding
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integer, pointer, dimension(:) :: array
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real, pointer :: pa(:)
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type(c_ptr) :: cptr
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!$omp target data use_device_addr(pa, cptr, array)
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!$omp end target data
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end subroutine
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!CHECK: func.func @{{.*}}mix_use_device_ptr_and_addr_and_map()
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!CHECK: omp.target_data map_entries(%{{.*}}, %{{.*}} : !fir.ref<i32>, !fir.ref<i32>) use_device_ptr(%{{.*}} : !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>) use_device_addr(%{{.*}}, %{{.*}} : !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>) {
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!CHECK: ^bb0(%{{.*}}: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>, %{{.*}}: !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>):
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subroutine mix_use_device_ptr_and_addr_and_map
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use iso_c_binding
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integer :: i, j
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integer, pointer, dimension(:) :: array
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real, pointer :: pa(:)
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type(c_ptr) :: cptr
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!$omp target data use_device_ptr(pa, cptr) use_device_addr(array) map(tofrom: i, j)
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!$omp end target data
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end subroutine
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!CHECK: func.func @{{.*}}only_use_map()
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!CHECK: omp.target_data map_entries(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}} : !fir.llvm_ptr<!fir.ref<!fir.array<?xf32>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xf32>>>>, !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>, !fir.llvm_ptr<!fir.ref<!fir.array<?xi32>>>, !fir.ref<!fir.box<!fir.ptr<!fir.array<?xi32>>>>) {
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subroutine only_use_map
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use iso_c_binding
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integer, pointer, dimension(:) :: array
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real, pointer :: pa(:)
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type(c_ptr) :: cptr
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!$omp target data map(pa, cptr, array)
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!$omp end target data
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end subroutine

‎flang/test/Semantics/OpenMP/use_device_ptr1.f90

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -27,7 +27,7 @@ subroutine omp_target_data
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a = arrayB
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!$omp end target data
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30-
!ERROR: 'a' in USE_DEVICE_PTR clause must be of type C_PTR
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!WARNING: Use of non-C_PTR type 'a' in USE_DEVICE_PTR is deprecated, use USE_DEVICE_ADDR instead
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!$omp target data map(tofrom: a) use_device_ptr(a)
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a = 2
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!$omp end target data

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