Flang OpenMP Support

This document outlines the OpenMP API features supported by Flang. It is intended as a general reference. For the most accurate information on unimplemented features, rely on the compiler’s TODO or “Not Yet Implemented” messages, which are considered authoritative. Flang provides complete implementation of the OpenMP 3.1 specification and partial implementation of OpenMP 4.0. The sections below summarize support status for OpenMP 4.0, 5.0, 5.1, 5.2, 6.0, and future 6.1. The table entries are derived from the information provided in the Version Differences subsection of the Features History section in the OpenMP standard.

The Status column uses the following values:

The OpenMP 4.0 section uses the historical Feature/Status/Comments format with an added Claimed By column. OpenMP 5.0 and newer sections use Feature/Status/Claimed By/Notes/Reviews to capture implementation state, ownership, and upstream references. Use GitHub usernames in Claimed By (for example @alice). Leave the cell blank when nobody has claimed the work.

This page is for OpenMP features that require changes in Flang compiler components (parser, semantics, lowering, diagnostics) and that may additionally entail corresponding runtime support. OpenMP features whose status does not involve updates to the Flang compiler are tracked under the Clang OpenMP Support page (clang/docs/OpenMPSupport.rst).

Updating This Page

  • When claiming a feature, set Status to in progress and add the GitHub username in Claimed By.

  • When a GitHub PR is opened, add the PR link in Reviews. Keep the claimant listed until the work is finished or unclaimed.

  • When support lands but remains incomplete, set Status to partial and summarize the missing parser, semantics, lowering, diagnostics, or test work in Notes.

  • When support is complete, set Status to done. Clear Claimed By if no further follow-up is expected.

  • When work is abandoned or not yet started, set Status to unclaimed, remove the claimant, and keep Notes focused on the missing implementation work.

Note: In the OpenMP 4.0 section, no distinction is made between support in Parser/Semantics, MLIR, Lowering, or the OpenMPIRBuilder.

OpenMP 4.0

Feature

Status

Claimed By

Comments

proc_bind clause

done

simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

declare simd construct

partial

Semantics coverage exists (for example flang/test/Semantics/OpenMP/declarative-directive01.f90) and lowering exists for key forms (for example flang/test/Lower/OpenMP/declare-simd-interface-body.f90), but coverage is not yet complete for all variants.

do simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

target data construct

done

target construct

done

target update construct

done

declare target directive

done

teams construct

done

distribute construct

done

distribute simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

distribute parallel loop construct

done

distribute parallel loop simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

depend clause

done

declare reduction construct

partial

Partial support, including user-defined reductions with derived types.

atomic construct extensions

done

cancel construct

done

cancellation point construct

done

parallel do simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

target teams construct

done

teams distribute construct

done

teams distribute simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

target teams distribute construct

done

teams distribute parallel loop construct

done

target teams distribute parallel loop construct

done

teams distribute parallel loop simd construct

partial

Implicit linearization is skipped if iv is a pointer or allocatable

target teams distribute parallel loop simd construct

partial

Implicit linearization is completely skipped

OpenMP 5.0

Feature

Status

Claimed By

Notes

Reviews

taskloop and combined taskloop forms

partial

Covered in semantics/lowering tests including flang/test/Semantics/OpenMP/taskloop01.f90, flang/test/Semantics/OpenMP/taskloop-simd01.f90, flang/test/Lower/OpenMP/taskloop.f90, and flang/test/Lower/OpenMP/master_taskloop_simd.f90. Lowering for taskloop simd and combined forms is still TODO.

llvm/llvm-project#138646, llvm/llvm-project#165851, llvm/llvm-project#187222

memory allocators

partial

Semantics coverage exists in flang/test/Semantics/OpenMP/allocators01.f90-flang/test/Semantics/OpenMP/allocators07.f90; lowering gaps remain (for example flang/lib/Lower/OpenMP/OpenMP.cpp TODO paths).

allocate directive and allocate clause

partial

Semantics coverage exists in flang/test/Semantics/OpenMP/allocate-directive.f90 and flang/test/Semantics/OpenMP/allocate-clause01.f90; lowering support expanded, with remaining TODO coverage (flang/test/Lower/OpenMP/Todo/allocate-clause-align.f90, flang/test/Lower/OpenMP/Todo/allocate-clause-allocator.f90).

llvm/llvm-project#121356, llvm/llvm-project#165719, llvm/llvm-project#165865, llvm/llvm-project#187167

metadirective

partial

Semantics coverage exists in flang/test/Semantics/OpenMP/metadirective-construct.f90; lowering support exists for several construct-selector paths (flang/test/Lower/OpenMP/metadirective-construct.f90, flang/test/Lower/OpenMP/metadirective-nothing.f90), but some selector/variant paths remain TODO-tracked in lowering.

llvm/llvm-project#159945, llvm/llvm-project#193664, llvm/llvm-project#194402, llvm/llvm-project#194424

support full defaultmap functionality

partial

Core coverage exists (flang/test/Lower/OpenMP/defaultmap.f90, flang/test/Semantics/OpenMP/defaultmap-clause-v50.f90), but lowering has known partial paths (for example defaultmap-firstprivate TODO tests).

llvm/llvm-project#135226, llvm/llvm-project#166715, llvm/llvm-project#167806, llvm/llvm-project#177389, llvm/llvm-project#190764

clause: uses_allocators

partial

Parsed/checked in semantics allocator tests, but lowering has explicit TODO handling (cp.processTODO<...UsesAllocators> in flang/lib/Lower/OpenMP/OpenMP.cpp).

clause: in_reduction

partial

Semantics and lowering coverage exists for several task/taskgroup/taskloop forms (flang/test/Semantics/OpenMP/in-reduction.f90, flang/test/Lower/OpenMP/task-inreduction.f90, flang/test/Lower/OpenMP/taskloop-inreduction.f90, flang/test/Lower/OpenMP/taskgroup-task_reduction02.f90); some target-related forms remain TODO (for example flang/test/Lower/OpenMP/Todo/target-inreduction.f90).

llvm/llvm-project#139704, llvm/llvm-project#205124

user-defined mappers

done

Supported with semantics/lowering/transform coverage.

llvm/llvm-project#140560, llvm/llvm-project#163860, llvm/llvm-project#167903, llvm/llvm-project#179936, llvm/llvm-project#189136

map array-section with implicit mapper

partial

Mapper and map coverage exists (flang/test/Lower/OpenMP/map-mapper.f90, flang/test/Lower/OpenMP/target-data-skip-mapper-calls.f90), with remaining iterator/modifier gaps in lowering (flang/lib/Lower/OpenMP/ClauseProcessor.cpp TODOs).

llvm/llvm-project#175133, llvm/llvm-project#177389

clause: use_device_addr for target data

done

Supported for core forms.

llvm/llvm-project#82834, llvm/llvm-project#176815

support non-contiguous array sections for target update

partial

Target update coverage exists (flang/test/Semantics/OpenMP/target-update01.f90, flang/test/Semantics/OpenMP/target-update-mapper.f90), with additional corner-case validation still ongoing.

pointer attachment

partial

Pointer mapping coverage exists (flang/test/Semantics/OpenMP/use_device_ptr.f90, flang/test/Lower/OpenMP/pointer-to-array.f90), with descriptor and attach-related TODOs remaining in lowering.

hints for the atomic construct

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/atomic-hint-clause.f90) and lowering coverage exists for common atomic forms; compare/fail forms remain partial.

conditional modifier for lastprivate clause

unclaimed

Lastprivate lowering/semantics coverage exists for base forms, but no dedicated support coverage for the conditional modifier was identified in current Flang tests.

task affinity

partial

Semantics and lowering coverage exists, including iterator-based affinity in task constructs (flang/test/Semantics/OpenMP/affinity-clause.f90, flang/test/Lower/OpenMP/task-affinity.f90).

llvm/llvm-project#179003, llvm/llvm-project#182222

iterator modifier for depend clause

done

Semantics/lowering coverage exists (flang/test/Lower/OpenMP/depend-iterator.f90).

llvm/llvm-project#189412

scan directive and inscan modifier for reduction

partial

Semantics and lowering coverage exists (flang/test/Semantics/OpenMP/scan1.f90, flang/test/Semantics/OpenMP/scan2.f90, flang/test/Lower/OpenMP/scan.f90), but breadth across all reduction combinations should continue to be validated.

llvm/llvm-project#102792, llvm/llvm-project#123254

reduction and in_reduction clauses on taskloop

partial

Taskloop reduction and in_reduction lowering coverage exists (flang/test/Lower/OpenMP/taskloop-reduction.f90, flang/test/Lower/OpenMP/taskloop-inreduction.f90), with remaining TODO coverage in some combinations.

llvm/llvm-project#205124

close modifier in map clause

partial

Close semantics are covered in targeted lowering tests (for example flang/test/Lower/OpenMP/cptr-usm-close-and-use-device-ptr.f90), with continued validation needed across broader mapping combinations.

llvm/llvm-project#163258

mapping Fortran pointer and allocatable variables

partial

Pointer/allocatable mapping coverage exists (flang/test/Semantics/OpenMP/use_device_ptr.f90, flang/test/Lower/OpenMP/wsloop-reduction-allocatable.f90, flang/test/Lower/OpenMP/wsloop-reduction-pointer.f90), but not all descriptor/attachment edge cases are complete.

declare variant directive

partial

Frontend semantics support is substantial (flang/test/Semantics/OpenMP/declare-variant.f90, flang/test/Semantics/OpenMP/declare-variant-match.f90), while lowering remains TODO-tracked (flang/test/Lower/OpenMP/Todo/declare-variant.f90).

llvm/llvm-project#130578, llvm/llvm-project#198799, llvm/llvm-project#206714

implicit declare target directive

unclaimed

No dedicated Flang parser/semantics/lowering coverage for implicit declare target handling was identified in current OpenMP test coverage.

requires directive

partial

Frontend and lowering coverage exists (flang/test/Semantics/OpenMP/requires01.f90-requires10.f90, flang/test/Lower/OpenMP/requires.f90), but some clauses are still flagged as unsupported (for example reverse_offload warning path).

llvm/llvm-project#204647

teams construct on host

done

Teams support is established and exercised across semantics/lowering coverage in Flang OpenMP tests.

loop construct and order(concurrent) clause

partial

Loop and order-related coverage exists (flang/test/Semantics/OpenMP/compiler-directives-loop.f90, flang/test/Semantics/OpenMP/order-clause01.f90, flang/test/Lower/OpenMP/loop-directive.f90, flang/test/Lower/OpenMP/order-clause.f90), with some transformations still evolving.

collapsing imperfectly nested loops

unclaimed

Current checks primarily diagnose non-perfect nests (for example flang/test/Semantics/OpenMP/do-collapse.f90), and no dedicated support for imperfect-nest collapsing was identified.

llvm/llvm-project#202435

if clause and nontemporal clause on simd

partial

SIMD nontemporal coverage exists (flang/test/Semantics/OpenMP/nontemporal.f90), but complete OpenMP 5.0-level coverage for all if(simd)/nontemporal combinations remains incomplete.

atomic in simd

unclaimed

No dedicated Flang OpenMP coverage for atomic-in-simd forms was identified in current parser/semantics/lowering tests.

detach clause on task and omp_fulfill_event routine

done

Flang semantics and lowering coverage exists (flang/test/Semantics/OpenMP/detach01.f90, flang/test/Semantics/OpenMP/detach02.f90, flang/test/Lower/OpenMP/task_detach.f90); runtime routine is available in OpenMP module/runtime.

llvm/llvm-project#119172, llvm/llvm-project#119128

taskloop construct can be canceled by cancel construct

partial

Dedicated lowering coverage exists (flang/test/Lower/OpenMP/taskloop-cancel.f90), and semantics checks include taskloop nesting constraints for cancel/cancellation-point.

reverse offload

unclaimed

Flang currently emits an unsupported warning path for reverse_offload in requires handling (flang/test/Semantics/OpenMP/requires01.f90).

llvm/llvm-project#204647

depend clause on taskwait

partial

Lowering is explicitly TODO-tracked (flang/test/Lower/OpenMP/Todo/taskwait-depend.f90); runtime support exists in OpenMP runtime tests.

llvm/llvm-project#111562

acquire/release clauses on atomic and flush

partial

Atomic acquire/release semantics coverage exists (flang/test/Semantics/OpenMP/atomic-mem-order.f90, flang/test/Semantics/OpenMP/atomic-compare.f90), but full end-to-end coverage breadth remains in progress.

mutexinoutset on depend clause

done

Semantics/lowering coverage exists for mutexinoutset depend handling (flang/test/Semantics/OpenMP/depend06.f90, flang/test/Lower/OpenMP/task.f90).

depobj construct

partial

Semantics coverage exists for v5.0+ forms (flang/test/Semantics/OpenMP/depobj-construct-v50.f90), but lowering still has TODO paths (flang/test/Lower/OpenMP/Todo/depobj-construct.f90, flang/test/Lower/OpenMP/Todo/depend-clause-depobj.f90).

combined master constructs (master taskloop, parallel master, parallel master taskloop, master taskloop simd, parallel master taskloop simd)

partial

Frontend/lowering coverage exists for multiple master combined forms (flang/test/Lower/OpenMP/parallel-master.f90, flang/test/Lower/OpenMP/master_taskloop_simd.f90, flang/test/Lower/OpenMP/parallel-master-taskloop-simd.f90) with additional completeness work tracked alongside taskloop combined forms.

llvm/llvm-project#113893

OpenMP 5.1

Feature

Status

Claimed By

Notes

Reviews

compare clause on atomic construct

partial

Semantics and lowering coverage exist (flang/test/Semantics/OpenMP/atomic-compare.f90, flang/test/Lower/OpenMP/atomic-compare.f90); remaining gaps are primarily fail/capture combinations and broader type coverage.

llvm/llvm-project#184761

fail clause on atomic construct

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/atomic-compare.f90), but lowering for fail(...) paths is still TODO (flang/test/Lower/OpenMP/Todo/atomic-compare-fail.f90). Complete lowering for compare+fail(+capture), then add non-TODO lowering tests.

llvm/llvm-project#184761

interop construct

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/interop-construct.f90), but lowering remains TODO-tracked (flang/lib/Lower/OpenMP/OpenMP.cpp TODO: OpenMPInteropConstruct; flang/test/Lower/OpenMP/Todo/interop-construct.f90).

dispatch construct

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/dispatch.f90), but lowering remains TODO-tracked (flang/lib/Lower/OpenMP/OpenMP.cpp TODO: OpenMPDispatchConstruct; flang/test/Lower/OpenMP/Todo/dispatch.f90).

masked construct

partial

Covered in semantics/lowering (flang/test/Semantics/OpenMP/masked.f90, flang/test/Lower/OpenMP/masked.f90).

llvm/llvm-project#91432

masked combined constructs

partial

Covered in lowering tests (flang/test/Lower/OpenMP/masked_taskloop.f90, flang/test/Lower/OpenMP/parallel-masked-taskloop.f90) with ongoing breadth expansion.

present map type modifier

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/present.f90) and map lowering exists, with ongoing completeness checks.

present modifier in motion clauses

partial

Motion/update coverage exists (flang/test/Semantics/OpenMP/target-update01.f90, flang/test/Semantics/OpenMP/target-update-mapper.f90), with ongoing completeness checks.

present in defaultmap clause

partial

Defaultmap semantics coverage exists (flang/test/Semantics/OpenMP/defaultmap-clause-v50.f90), with ongoing completeness checks.

thread_limit clause on target construct

partial

Lowering/semantics coverage exists for thread-limit dimensions (flang/test/Lower/OpenMP/thread-limit-dims.f90), with additional target interactions still under validation.

llvm/llvm-project#171454, llvm/llvm-project#171825

has_device_addr clause on target construct

partial

Semantics/lowering coverage exists (flang/test/Lower/OpenMP/has_device_addr-mapinfo.f90) with ongoing validation for all mapping combinations.

iterators in map or motion clauses

partial

Some iterator coverage exists (flang/test/Lower/OpenMP/depend-iterator.f90), but lowering still has explicit iterator TODOs in flang/lib/Lower/OpenMP/ClauseProcessor.cpp.

omp_all_memory reserved locator for depend clause

partial

Locator parsing/semantics groundwork exists, with remaining TODO lowering coverage for reserved locator handling (flang/test/Lower/OpenMP/Todo/locator-reserved.f90).

llvm/llvm-project#203910

align clause on allocate directive and allocator/align modifiers on allocate clause

partial

Allocate directive/clause support is present, but align-related lowering remains TODO-tracked (flang/test/Lower/OpenMP/Todo/allocate-clause-align.f90).

llvm/llvm-project#121356, llvm/llvm-project#165719

target_device selector

partial

Semantics coverage exists for target_device selectors in metadirective/declare-variant matching (flang/test/Semantics/OpenMP/metadirective-device.f90, flang/test/Semantics/OpenMP/declare-variant-match.f90).

llvm/llvm-project#123243, llvm/llvm-project#206714

adjust_args and append_args on declare variant

unclaimed

Parsing accepts forms, but semantics currently diagnose both clauses as not yet implemented (flang/test/Semantics/OpenMP/declare-variant-match.f90, flang/test/Semantics/OpenMP/declare-variant.f90).

llvm/llvm-project#206714

indirect clause on declare target

partial

Parser coverage exists (flang/test/Parser/OpenMP/declare-target-indirect-tree.f90), while lowering remains TODO-tracked (flang/test/Lower/OpenMP/Todo/omp-clause-indirect.f90).

llvm/llvm-project#143505

error directive

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/error.f90), but lowering still has explicit TODO coverage (flang/test/Lower/OpenMP/Todo/error.f90).

llvm/llvm-project#121509, llvm/llvm-project#206175

nothing directive

done

Parser and lowering coverage exists for standalone and metadirective-selected forms (flang/test/Parser/OpenMP/nothing.f90, flang/test/Lower/OpenMP/nothing.f90, flang/test/Lower/OpenMP/metadirective-nothing.f90).

llvm/llvm-project#193664, llvm/llvm-project#202679

tile and unroll constructs

partial

Semantics coverage exists across tile/unroll and loop-transformation tests (flang/test/Semantics/OpenMP/tile01.f90, flang/test/Semantics/OpenMP/tile09.f90, flang/test/Semantics/OpenMP/loop-transformation-construct01.f90), with additional lowering/transform completeness work ongoing.

llvm/llvm-project#160298, llvm/llvm-project#185296, llvm/llvm-project#188025

scope construct

partial

Scope construct support is available, with follow-on completeness work still in progress for some combinations (see also OpenMP 5.2 scope-related rows).

llvm/llvm-project#113700, llvm/llvm-project#193098

assumes directives

unclaimed

Lowering still has explicit TODO (flang/lib/Lower/OpenMP/OpenMP.cpp TODO: OpenMP ASSUMES declaration; flang/test/Lower/OpenMP/Todo/assumes.f90).

llvm/llvm-project#102008

assume directive

unclaimed

Lowering still has explicit TODO (flang/lib/Lower/OpenMP/OpenMP.cpp TODO: OpenMP ASSUME construct; flang/test/Lower/OpenMP/Todo/assume.f90).

llvm/llvm-project#102008

default(firstprivate)

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/default02.f90), but defaultmap-firstprivate lowering remains partial (flang/test/Lower/OpenMP/Todo/defaultmap-clause-firstprivate.f90).

default(private)

partial

Semantics/default-clause coverage exists (flang/test/Semantics/OpenMP/default.f90, flang/test/Semantics/OpenMP/default02.f90) with ongoing lowering completeness checks.

inoutset in depend clause

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/depend06.f90) with broader lowering/runtime verification ongoing.

nowait clause on taskwait

partial

Taskwait coverage exists (flang/test/Semantics/OpenMP/taskwait.f90, flang/test/Lower/OpenMP/taskwait.f90), with nowait+depend combinations still partial (flang/test/Lower/OpenMP/Todo/taskwait-nowait.f90).

seq_cst clause on flush

done

OpenMP 5.1 flush seq_cst semantics coverage exists (flang/test/Semantics/OpenMP/flush02.f90).

llvm/llvm-project#114072

omp_atv_serialized and omp_atv_default values for alloctrait_key

unclaimed

No dedicated Flang parser/semantics/lowering coverage for these alloctrait values was identified in current OpenMP tests.

strict modifier for taskloop construct

unclaimed

No dedicated parser/semantics/lowering coverage for the taskloop strict modifier was identified in current Flang OpenMP tests.

OpenMP 5.2

Feature

Status

Claimed By

Notes

Reviews

if clause on teams construct

partial

Semantics coverage exists for teams-specific if forms (for example flang/test/Semantics/OpenMP/if-clause.f90 with if(teams: ...) cases).

ompx and omx sentinel for implementation extensions in free/fixed source

partial

Extension semantics coverage exists for ompx forms (flang/test/Semantics/OpenMP/ompx-bare.f90), while broader sentinel coverage (including fixed-form omx) remains limited.

llvm/llvm-project#111106

allow copyprivate and nowait clause on starting directive of construct

done

Semantics coverage includes valid starting-directive uses (!$omp single nowait, !$omp single copyprivate(...)) in flang/test/Semantics/OpenMP/single04.f90.

llvm/llvm-project#204339, llvm/llvm-project#205607

step modifier

unclaimed

Add parser+semantics acceptance/diagnostics for OpenMP 5.2 step-modifier forms, then add lowering coverage showing emitted loop metadata/ops for accepted cases.

declare mapper iterator modifier

unclaimed

Parser and semantics should accept iterator-modified DECLARE MAPPER forms, then lowering must thread iterator bounds through map info generation (see related TODO test flang/test/Lower/OpenMP/Todo/declare-mapper-iterator.f90).

present modifier in map clauses on declare mapper

unclaimed

Iterator coverage is tracked separately above; no dedicated present-modifier support coverage was identified for DECLARE MAPPER map clauses.

enter clause replaces to clause on declare target

done

Semantics coverage exists for declare target enter(...) forms (flang/test/Semantics/OpenMP/declare-target01.f90, flang/test/Semantics/OpenMP/requires05.f90).

llvm/llvm-project#110015

otherwise clause on metadirectives

unclaimed

BEGIN/END METADIRECTIVE frontend support exists, but metadirective lowering remains TODO (flang/lib/Lower/OpenMP/OpenMP.cpp). Implement lowering selection for OTHERWISE and add dedicated lowering tests for construct selection.

llvm/llvm-project#194402

doacross with omp_cur_iteration

unclaimed

Implement parser/semantics validation for omp_cur_iteration placement and lowering of doacross dependence tokens, then add semantics+lowering tests for source/sink combinations.

implicit map type for target enter and exit data

unclaimed

Define implicit-map behavior for enter/exit data in lowering map finalization and add dedicated tests covering pointer/allocatable/component cases and mapper interactions.

allocate and firstprivate on scope directive

partial

Scope lowering coverage includes allocate and firstprivate on scope directives (flang/test/Lower/OpenMP/scope.f90, flang/test/Lower/OpenMP/target-scope.f90).

llvm/llvm-project#193098

loop consistency changes for order clause

unclaimed

Extend semantic loop-consistency checks for updated ORDER rules and add diagnostics tests for invalid nest/ordering combinations.

keep original base pointer on map without matched candidate

unclaimed

Update map finalization so unmatched candidates preserve original base-pointer mapping semantics; add lowering tests for pointer-member mapping regressions.

pure procedure support for certain directives

unclaimed

Codify semantics restrictions for PURE procedures with these directives and add lowering tests ensuring no illegal side-effecting ops are introduced.

ALLOCATE statement support for allocators

unclaimed

Wire OpenMP allocator semantics into Fortran ALLOCATE statement handling and add semantics+lowering tests for allocator traits and error paths.

dispatch extension supporting end directive

unclaimed

Base dispatch support is partial, and no dedicated support coverage for the OpenMP 5.2 dispatch end-directive extension was identified.

minus operator deprecation handling

partial

Partially handled in semantic diagnostics.

linear clause syntax deprecation

unclaimed

Add semantic deprecation diagnostics with fix-it guidance and tests for accepted/deprecated spellings.

map clause modifiers without commas (deprecation)

unclaimed

Add parser/semantics deprecation diagnostics for comma-less map modifiers and tests that verify warning text and accepted replacements.

uses_allocators list syntax (deprecation)

unclaimed

Add diagnostics for deprecated uses_allocators list syntax and ensure lowering still handles canonical replacements.

default clause on metadirectives (deprecation)

unclaimed

Add dedicated metadirective deprecation diagnostics and tests for legacy/default-clause usage.

destroy clause syntax on depobj (deprecation)

partial

Deprecation diagnostics are implemented (for example warning coverage in flang/test/Semantics/OpenMP/depobj-construct-v52.f90).

source and sink task-dependence modifiers (deprecation)

partial

Deprecation diagnostics are implemented (for example warning coverage in flang/test/Semantics/OpenMP/depobj-construct-v52.f90).

interop type position on init clause (deprecation)

unclaimed

Add parser+semantics deprecation diagnostics for legacy interop init type-position forms and tests showing canonical replacement.

OpenMP 6.0

Feature

Status

Claimed By

Notes

Reviews

threadset clause

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/threadset-clause.f90) with ongoing lowering/runtime validation.

llvm/llvm-project#169856

groupprivate directive

partial

Semantics and lowering coverage exists (flang/test/Semantics/OpenMP/groupprivate.f90, flang/test/Lower/OpenMP/groupprivate.f90, flang/test/Lower/OpenMP/groupprivate-modfile.f90), with remaining limitations in lowering scope/placement (for example currently materialized for teams-based paths).

llvm/llvm-project#166199, llvm/llvm-project#166214, llvm/llvm-project#180934

recording of task graphs

in progress

Semantics coverage exists (flang/test/Semantics/OpenMP/taskgraph.f90).

workdistribute construct

partial

Semantics/lowering/transform coverage exists (flang/test/Semantics/OpenMP/workdistribute01.f90, flang/test/Lower/OpenMP/workdistribute.f90, flang/test/Transforms/OpenMP/lower-workdistribute-fission.mlir) including target teams placement updates; some team-nesting combinations still intentionally diagnose as unsupported.

llvm/llvm-project#154377, llvm/llvm-project#154378, llvm/llvm-project#140523, llvm/llvm-project#199006

map clause updates (v6.0 forms)

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/map-clause-v60.f90) with ongoing lowering completeness work.

map modifier updates (v6.0 and v6.1 forms)

partial

Semantics coverage exists (flang/test/Semantics/OpenMP/map-modifiers-v60.f90, flang/test/Semantics/OpenMP/map-modifiers-v61.f90) with ongoing lowering completeness work.

llvm/llvm-project#172080, llvm/llvm-project#176810

loop fusion transformation

done

Supported.

llvm/llvm-project#161213

loop construct with DO CONCURRENT

in progress

Experimental support is available and under active development.

llvm/llvm-project#178138, llvm/llvm-project#190990

optional argument for all clauses

partial

Semantics coverage exists across clause tests (for example flang/test/Semantics/OpenMP/if-clause-50.f90).

canonical loop sequences

partial

Related loop/transform coverage exists (flang/test/Semantics/OpenMP/loop-transformation-construct01.f90, flang/test/Lower/OpenMP/loop-directive.f90).

llvm/llvm-project#161213, llvm/llvm-project#168884, llvm/llvm-project#170734, llvm/llvm-project#170735

pure directives in DO CONCURRENT

unclaimed

Define exact PURE+DO CONCURRENT directive legality in semantics and add lowering tests proving accepted forms remain side-effect safe.

extensions to depobj construct

unclaimed

Semantics and deprecation diagnostics exist for several depobj forms, but extension support remains incomplete in lowering (for example flang/test/Lower/OpenMP/Todo/depobj-construct.f90). Implement lowering for extension operands/modifiers and add non-TODO lowering tests.

extensions to atomic construct

partial

Atomic compare lowering is now available (flang/test/Lower/OpenMP/atomic-compare.f90), but fail/capture-related extension paths remain incomplete (flang/test/Lower/OpenMP/Todo/atomic-compare-fail.f90).

llvm/llvm-project#184761

clarifications to Fortran map semantics

unclaimed

Document each 6.0 clarification point against existing map finalization behavior, then add focused semantics/lowering regression tests for unresolved points.

OpenMP 6.1 (Future / Experimental)

Feature

Status

Claimed By

Notes

Reviews

dyn_groupprivate clause

in progress

Experimental and in progress (flang/test/Semantics/OpenMP/dyn-groupprivate.f90).

llvm/llvm-project#166199, llvm/llvm-project#166214

dims strict behavior (multidimensional teams/leagues)

in progress

Experimental and in progress (flang/test/Lower/OpenMP/thread-limit-dims.f90).

llvm/llvm-project#171454, llvm/llvm-project#171767, llvm/llvm-project#171825

attach map-type modifier

partial

Parser/semantics/lowering coverage exists (flang/test/Parser/OpenMP/map-modifiers-v61.f90, flang/test/Semantics/OpenMP/map-modifiers-v61.f90, flang/test/Lower/OpenMP/attach-and-ref-modifier.f90); broader integration coverage across additional mapping contexts is still in progress.

llvm/llvm-project#177715, llvm/llvm-project#177301, llvm/llvm-project#177302

need_device_ptr modifier for adjust_args clause

unclaimed

Add parser+semantics support for modifier placement/rules, then lower adjust_args with device-pointer selection semantics and add end-to-end tests.

fallback modifier for use_device_ptr clause

unclaimed

Add parser+semantics diagnostics and lowering behavior for fallback selection; add tests for fallback and non-fallback resolution paths.

loop flatten transformation

unclaimed

Implement parser/semantics acceptance and lowering transform plumbing, then add transform/lowering tests demonstrating flattened loop mapping.

loop grid and tile modifiers for sizes clause

unclaimed

Extend clause parsing/semantics for grid/tile size modifiers and add lowering tests showing generated loop partitioning metadata/ops.

Extensions

ATOMIC construct

The implementation of the ATOMIC construct follows OpenMP 6.0 with the following extensions:

  • x = x is an allowed form of ATOMIC UPDATE. This is motivated by the fact that the equivalent forms x = x+0 or x = x*1 are allowed.

  • Explicit type conversions are allowed in ATOMIC READ, WRITE or UPDATE constructs, and in the capture statement in ATOMIC UPDATE CAPTURE. The OpenMP spec requires intrinsic- or pointer-assignments, which include (as per the Fortran standard) implicit type conversions. Since such conversions need to be handled, allowing explicit conversions comes at no extra cost.

  • A literal .true. or .false. is an allowed condition in ATOMIC UPDATE COMPARE. [1]

  • A logical variable is an allowed form of the condition even if its value is not computed within the ATOMIC UPDATE COMPARE construct [1].

  • expr equalop x is an allowed condition in ATOMIC UPDATE COMPARE. [1]

[1] Code generation for ATOMIC UPDATE COMPARE is not implemented yet.