1.. raw:: html 2 3 <style type="text/css"> 4 .none { background-color: #FFCCCC } 5 .part { background-color: #FFFF99 } 6 .good { background-color: #CCFF99 } 7 </style> 8 9.. role:: none 10.. role:: part 11.. role:: good 12 13.. contents:: 14 :local: 15 16OpenMP Support 17============== 18 19Clang fully supports OpenMP 4.5. Clang supports offloading to X86_64, AArch64, 20PPC64[LE] and has `basic support for Cuda devices`_. 21 22* #pragma omp declare simd: :part:`Partial`. We support parsing/semantic 23 analysis + generation of special attributes for X86 target, but still 24 missing the LLVM pass for vectorization. 25 26In addition, the LLVM OpenMP runtime `libomp` supports the OpenMP Tools 27Interface (OMPT) on x86, x86_64, AArch64, and PPC64 on Linux, Windows, and macOS. 28 29For the list of supported features from OpenMP 5.0 see `OpenMP implementation details`_. 30 31General improvements 32==================== 33- New collapse clause scheme to avoid expensive remainder operations. 34 Compute loop index variables after collapsing a loop nest via the 35 collapse clause by replacing the expensive remainder operation with 36 multiplications and additions. 37 38- The default schedules for the `distribute` and `for` constructs in a 39 parallel region and in SPMD mode have changed to ensure coalesced 40 accesses. For the `distribute` construct, a static schedule is used 41 with a chunk size equal to the number of threads per team (default 42 value of threads or as specified by the `thread_limit` clause if 43 present). For the `for` construct, the schedule is static with chunk 44 size of one. 45 46- Simplified SPMD code generation for `distribute parallel for` when 47 the new default schedules are applicable. 48 49- When using the collapse clause on a loop nest the default behavior 50 is to automatically extend the representation of the loop counter to 51 64 bits for the cases where the sizes of the collapsed loops are not 52 known at compile time. To prevent this conservative choice and use 53 at most 32 bits, compile your program with the 54 `-fopenmp-optimistic-collapse`. 55 56.. _basic support for Cuda devices: 57 58Cuda devices support 59==================== 60 61Directives execution modes 62-------------------------- 63 64Clang code generation for target regions supports two modes: the SPMD and 65non-SPMD modes. Clang chooses one of these two modes automatically based on the 66way directives and clauses on those directives are used. The SPMD mode uses a 67simplified set of runtime functions thus increasing performance at the cost of 68supporting some OpenMP features. The non-SPMD mode is the most generic mode and 69supports all currently available OpenMP features. The compiler will always 70attempt to use the SPMD mode wherever possible. SPMD mode will not be used if: 71 72 - The target region contains user code (other than OpenMP-specific 73 directives) in between the `target` and the `parallel` directives. 74 75Data-sharing modes 76------------------ 77 78Clang supports two data-sharing models for Cuda devices: `Generic` and `Cuda` 79modes. The default mode is `Generic`. `Cuda` mode can give an additional 80performance and can be activated using the `-fopenmp-cuda-mode` flag. In 81`Generic` mode all local variables that can be shared in the parallel regions 82are stored in the global memory. In `Cuda` mode local variables are not shared 83between the threads and it is user responsibility to share the required data 84between the threads in the parallel regions. 85 86 87Features not supported or with limited support for Cuda devices 88--------------------------------------------------------------- 89 90- Cancellation constructs are not supported. 91 92- Doacross loop nest is not supported. 93 94- User-defined reductions are supported only for trivial types. 95 96- Nested parallelism: inner parallel regions are executed sequentially. 97 98- Automatic translation of math functions in target regions to device-specific 99 math functions is not implemented yet. 100 101- Debug information for OpenMP target regions is supported, but sometimes it may 102 be required to manually specify the address class of the inspected variables. 103 In some cases the local variables are actually allocated in the global memory, 104 but the debug info may be not aware of it. 105 106 107.. _OpenMP implementation details: 108 109OpenMP 5.0 Implementation Details 110================================= 111 112The following table provides a quick overview over various OpenMP 5.0 features 113and their implementation status. Please post on the 114`Discourse forums (Runtimes - OpenMP category)`_ for more 115information or if you want to help with the 116implementation. 117 118+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 119|Category | Feature | Status | Reviews | 120+==============================+==============================================================+==========================+=======================================================================+ 121| loop | support != in the canonical loop form | :good:`done` | D54441 | 122+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 123| loop | #pragma omp loop (directive) | :part:`worked on` | | 124+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 125| loop | collapse imperfectly nested loop | :good:`done` | | 126+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 127| loop | collapse non-rectangular nested loop | :good:`done` | | 128+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 129| loop | C++ range-base for loop | :good:`done` | | 130+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 131| loop | clause: if for SIMD directives | :good:`done` | | 132+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 133| loop | inclusive scan (matching C++17 PSTL) | :good:`done` | | 134+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 135| memory management | memory allocators | :good:`done` | r341687,r357929 | 136+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 137| memory management | allocate directive and allocate clause | :good:`done` | r355614,r335952 | 138+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 139| OMPD | OMPD interfaces | :part:`not upstream` | https://github.com/OpenMPToolsInterface/LLVM-openmp/tree/ompd-tests | 140+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 141| OMPT | OMPT interfaces | :part:`mostly done` | | 142+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 143| thread affinity | thread affinity | :good:`done` | | 144+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 145| task | taskloop reduction | :good:`done` | | 146+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 147| task | task affinity | :part:`not upstream` | https://github.com/jklinkenberg/openmp/tree/task-affinity | 148+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 149| task | clause: depend on the taskwait construct | :part:`mostly done` | D113540 (regular codegen only) | 150+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 151| task | depend objects and detachable tasks | :good:`done` | | 152+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 153| task | mutexinoutset dependence-type for tasks | :good:`done` | D53380,D57576 | 154+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 155| task | combined taskloop constructs | :good:`done` | | 156+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 157| task | master taskloop | :good:`done` | | 158+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 159| task | parallel master taskloop | :good:`done` | | 160+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 161| task | master taskloop simd | :good:`done` | | 162+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 163| task | parallel master taskloop simd | :good:`done` | | 164+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 165| SIMD | atomic and simd constructs inside SIMD code | :good:`done` | | 166+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 167| SIMD | SIMD nontemporal | :good:`done` | | 168+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 169| device | infer target functions from initializers | :part:`worked on` | | 170+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 171| device | infer target variables from initializers | :part:`worked on` | | 172+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 173| device | OMP_TARGET_OFFLOAD environment variable | :good:`done` | D50522 | 174+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 175| device | support full 'defaultmap' functionality | :good:`done` | D69204 | 176+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 177| device | device specific functions | :good:`done` | | 178+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 179| device | clause: device_type | :good:`done` | | 180+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 181| device | clause: extended device | :good:`done` | | 182+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 183| device | clause: uses_allocators clause | :good:`done` | | 184+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 185| device | clause: in_reduction | :part:`worked on` | r308768 | 186+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 187| device | omp_get_device_num() | :part:`worked on` | D54342 | 188+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 189| device | structure mapping of references | :none:`unclaimed` | | 190+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 191| device | nested target declare | :good:`done` | D51378 | 192+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 193| device | implicitly map 'this' (this[:1]) | :good:`done` | D55982 | 194+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 195| device | allow access to the reference count (omp_target_is_present) | :good:`done` | | 196+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 197| device | requires directive | :part:`partial` | | 198+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 199| device | clause: unified_shared_memory | :good:`done` | D52625,D52359 | 200+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 201| device | clause: unified_address | :part:`partial` | | 202+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 203| device | clause: reverse_offload | :none:`unclaimed parts` | D52780 | 204+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 205| device | clause: atomic_default_mem_order | :good:`done` | D53513 | 206+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 207| device | clause: dynamic_allocators | :part:`unclaimed parts` | D53079 | 208+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 209| device | user-defined mappers | :part:`worked on` | D56326,D58638,D58523,D58074,D60972,D59474 | 210+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 211| device | mapping lambda expression | :good:`done` | D51107 | 212+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 213| device | clause: use_device_addr for target data | :good:`done` | | 214+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 215| device | support close modifier on map clause | :good:`done` | D55719,D55892 | 216+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 217| device | teams construct on the host device | :part:`done` | r371553 | 218+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 219| device | support non-contiguous array sections for target update | :good:`done` | | 220+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 221| device | pointer attachment | :none:`unclaimed` | | 222+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 223| device | map clause reordering based on map types | :none:`unclaimed` | | 224+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 225| atomic | hints for the atomic construct | :good:`done` | D51233 | 226+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 227| base language | C11 support | :good:`done` | | 228+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 229| base language | C++11/14/17 support | :good:`done` | | 230+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 231| base language | lambda support | :good:`done` | | 232+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 233| misc | array shaping | :good:`done` | D74144 | 234+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 235| misc | library shutdown (omp_pause_resource[_all]) | :none:`unclaimed parts` | D55078 | 236+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 237| misc | metadirectives | :part:`worked on` | D91944 | 238+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 239| misc | conditional modifier for lastprivate clause | :good:`done` | | 240+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 241| misc | iterator and multidependences | :good:`done` | | 242+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 243| misc | depobj directive and depobj dependency kind | :good:`done` | | 244+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 245| misc | user-defined function variants | :part:`worked on` | D67294, D64095, D71847, D71830, D109635 | 246+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 247| misc | pointer/reference to pointer based array reductions | :none:`unclaimed` | | 248+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 249| misc | prevent new type definitions in clauses | :good:`done` | | 250+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 251| memory model | memory model update (seq_cst, acq_rel, release, acquire,...) | :good:`done` | | 252+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 253 254 255OpenMP 5.1 Implementation Details 256================================= 257 258The following table provides a quick overview over various OpenMP 5.1 features 259and their implementation status, as defined in the technical report 8 (TR8). 260Please post on the 261`Discourse forums (Runtimes - OpenMP category)`_ for more 262information or if you want to help with the 263implementation. 264 265+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 266|Category | Feature | Status | Reviews | 267+==============================+==============================================================+==========================+=======================================================================+ 268| atomic | 'compare' clause on atomic construct | :good:`done` | D120290, D120007, D118632, D120200, D116261, D118547, D116637 | 269+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 270| atomic | 'fail' clause on atomic construct | :part:`worked on` | | 271+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 272| base language | C++ attribute specifier syntax | :good:`done` | D105648 | 273+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 274| device | 'present' map type modifier | :good:`done` | D83061, D83062, D84422 | 275+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 276| device | 'present' motion modifier | :good:`done` | D84711, D84712 | 277+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 278| device | 'present' in defaultmap clause | :good:`done` | D92427 | 279+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 280| device | map clause reordering reordering based on 'present' modifier | :none:`unclaimed` | | 281+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 282| device | device-specific environment variables | :none:`unclaimed` | | 283+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 284| device | omp_target_is_accessible routine | :none:`unclaimed` | | 285+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 286| device | omp_get_mapped_ptr routine | :none:`done` | | 287+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 288| device | new async target memory copy routines | :none:`unclaimed` | | 289+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 290| device | thread_limit clause on target construct | :none:`worked on` | | 291+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 292| device | has_device_addr clause on target construct | :none:`unclaimed` | | 293+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 294| device | iterators in map clause or motion clauses | :none:`unclaimed` | | 295+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 296| device | indirect clause on declare target directive | :none:`unclaimed` | | 297+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 298| device | allow virtual functions calls for mapped object on device | :none:`unclaimed` | | 299+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 300| device | interop construct | :part:`partial` | parsing/sema done: D98558, D98834, D98815 | 301+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 302| device | assorted routines for querying interoperable properties | :none:`unclaimed` | | 303+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 304| loop | Loop tiling transformation | :good:`done` | D76342 | 305+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 306| loop | Loop unrolling transformation | :good:`done` | D99459 | 307+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 308| loop | 'reproducible'/'unconstrained' modifiers in 'order' clause | :part:`partial` | D127855 | 309+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 310| memory management | alignment for allocate directive and clause | :part:`worked on` | | 311+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 312| memory management | new memory management routines | :none:`unclaimed` | | 313+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 314| memory management | changes to omp_alloctrait_key enum | :none:`unclaimed` | | 315+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 316| memory model | seq_cst clause on flush construct | :none:`unclaimed` | | 317+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 318| misc | 'omp_all_memory' keyword and use in 'depend' clause | :good:`done` | D125828, D126321 | 319+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 320| misc | error directive | :none:`unclaimed` | | 321+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 322| misc | scope construct | :none:`unclaimed` | | 323+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 324| misc | routines for controlling and querying team regions | :none:`unclaimed` | | 325+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 326| misc | changes to ompt_scope_endpoint_t enum | :none:`unclaimed` | | 327+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 328| misc | omp_display_env routine | :none:`unclaimed` | | 329+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 330| misc | extended OMP_PLACES syntax | :none:`unclaimed` | | 331+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 332| misc | OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT env vars | :none:`unclaimed` | | 333+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 334| misc | 'target_device' selector in context specifier | :none:`unclaimed` | | 335+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 336| misc | begin/end declare variant | :good:`done` | D71179 | 337+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 338| misc | dispatch construct and function variant argument adjustment | :part:`worked on` | D99537, D99679 | 339+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 340| misc | assume and assumes directives | :part:`worked on` | | 341+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 342| misc | nothing directive | :part:`worked on` | | 343+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 344| misc | masked construct and related combined constructs | :part:`worked on` | D99995, D100514 | 345+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 346| misc | default(firstprivate) & default(private) | :part:`partial` | firstprivate done: D75591 | 347+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 348| other | deprecating master construct | :none:`unclaimed` | | 349+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 350| OMPT | new barrier types added to ompt_sync_region_t enum | :none:`unclaimed` | | 351+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 352| OMPT | async data transfers added to ompt_target_data_op_t enum | :none:`unclaimed` | | 353+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 354| OMPT | new barrier state values added to ompt_state_t enum | :none:`unclaimed` | | 355+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 356| OMPT | new 'emi' callbacks for external monitoring interfaces | :none:`unclaimed` | | 357+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 358| task | 'strict' modifier for taskloop construct | :none:`unclaimed` | | 359+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 360| task | inoutset in depend clause | :none:`unclaimed` | | 361+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 362| task | nowait clause on taskwait | :part:`worked on` | | 363+------------------------------+--------------------------------------------------------------+--------------------------+-----------------------------------------------------------------------+ 364 365OpenMP Extensions 366================= 367 368The following table provides a quick overview over various OpenMP 369extensions and their implementation status. These extensions are not 370currently defined by any standard, so links to associated LLVM 371documentation are provided. As these extensions mature, they will be 372considered for standardization. Please post on the 373`Discourse forums (Runtimes - OpenMP category)`_ to provide feedback. 374 375+------------------------------+-----------------------------------------------------------------------------------+--------------------------+--------------------------------------------------------+ 376|Category | Feature | Status | Reviews | 377+==============================+===================================================================================+==========================+========================================================+ 378| atomic extension | `'atomic' strictly nested within 'teams' | :good:`prototyped` | D126323 | 379| | <https://openmp.llvm.org/docs/openacc/OpenMPExtensions.html#atomicWithinTeams>`_ | | | 380+------------------------------+-----------------------------------------------------------------------------------+--------------------------+--------------------------------------------------------+ 381| device extension | `'ompx_hold' map type modifier | :good:`prototyped` | D106509, D106510 | 382| | <https://openmp.llvm.org/docs/openacc/OpenMPExtensions.html#ompx-hold>`_ | | | 383+------------------------------+-----------------------------------------------------------------------------------+--------------------------+--------------------------------------------------------+ 384 385.. _Discourse forums (Runtimes - OpenMP category): https://discourse.llvm.org/c/runtimes/openmp/35 386