[flang][OpenMP] Frontend support for DEVICE_SAFESYNC #163560

kparzysz · 2025-10-15T13:19:23Z

Add parsing and semantic checks for DEVICE_SAFESYNC clause. No lowering.

REQUIRES clauses apply to the compilation unit, which the OpenMP spec defines as the program unit in Fortran. Don't set REQUIRES flags on all containing scopes, only on the containng program unit, where flags coming from different directives are gathered. If we wanted to set the flags on subprograms, we would need to first accummulate all of them, then propagate them down to all subprograms. That is not done as it is not necessary (the containing program unit is always available).

For each program unit, collect the set of requirements from REQUIRES directives in the source, and modules used by the program unit, and add them to the details of the program unit symbol. The requirements in the symbol details as now stored as clauses. Since requirements need to be emitted in the module files as OpenMP directives, this makes the clause emission straightforward via getOpenMPClauseName. Each program unit, including modules, the corresponding symbol will have the transitive closure of the requirements for everything contained or used in that program unit.

OpenMP 6.0 added an optional logical parameter to the requirement clauses (except ATOMIC_DEFAULT_MEM_ORDER) to indicate whether the clause should take effect or not. The parameter defaults to true if not specified. The parameter value is a compile-time constant expression, but it may require folding to get the final value. Since name resolution happens before folding, the argument expression needs to be analyzed by hand. The determination of the value needs to happen during name resolution because the requirement directives need to be available through module files (and the module reader doesn't to semantic checks beyonn name resolution).

Add parsing and semantic checks for DEVICE_SAFESYNC clause. No lowering.

llvmbot · 2025-10-15T13:19:57Z

@llvm/pr-subscribers-flang-fir-hlfir
@llvm/pr-subscribers-flang-openmp
@llvm/pr-subscribers-flang-parser

@llvm/pr-subscribers-flang-semantics

Author: Krzysztof Parzyszek (kparzysz)

Changes

Add parsing and semantic checks for DEVICE_SAFESYNC clause. No lowering.

Full diff: https://github.com/llvm/llvm-project/pull/163560.diff

9 Files Affected:

(modified) flang/include/flang/Lower/OpenMP/Clauses.h (+1)
(modified) flang/include/flang/Parser/dump-parse-tree.h (+1)
(modified) flang/include/flang/Parser/parse-tree.h (+8)
(modified) flang/lib/Lower/OpenMP/Clauses.cpp (+12)
(modified) flang/lib/Parser/openmp-parsers.cpp (+3)
(modified) flang/lib/Semantics/check-omp-structure.cpp (+5)
(modified) flang/lib/Semantics/resolve-directives.cpp (+1)
(modified) llvm/include/llvm/Frontend/OpenMP/ClauseT.h (+17-8)
(modified) llvm/include/llvm/Frontend/OpenMP/OMP.td (+4)

diff --git a/flang/include/flang/Lower/OpenMP/Clauses.h b/flang/include/flang/Lower/OpenMP/Clauses.h
index 273e61166fd9d..74924661d9a03 100644
--- a/flang/include/flang/Lower/OpenMP/Clauses.h
+++ b/flang/include/flang/Lower/OpenMP/Clauses.h
@@ -214,6 +214,7 @@ using Depend = tomp::clause::DependT<TypeTy, IdTy, ExprTy>;
 using Destroy = tomp::clause::DestroyT<TypeTy, IdTy, ExprTy>;
 using Detach = tomp::clause::DetachT<TypeTy, IdTy, ExprTy>;
 using Device = tomp::clause::DeviceT<TypeTy, IdTy, ExprTy>;
+using DeviceSafesync = tomp::clause::DeviceSafesyncT<TypeTy, IdTy, ExprTy>;
 using DeviceType = tomp::clause::DeviceTypeT<TypeTy, IdTy, ExprTy>;
 using DistSchedule = tomp::clause::DistScheduleT<TypeTy, IdTy, ExprTy>;
 using Doacross = tomp::clause::DoacrossT<TypeTy, IdTy, ExprTy>;
diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index 8854dc2267c8e..7377a3a4e3ca1 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -557,6 +557,7 @@ class ParseTreeDumper {
   NODE(OmpDeviceClause, Modifier)
   NODE(parser, OmpDeviceModifier)
   NODE_ENUM(OmpDeviceModifier, Value)
+  NODE(parser, OmpDeviceSafesyncClause)
   NODE(parser, OmpDeviceTypeClause)
   NODE_ENUM(OmpDeviceTypeClause, DeviceTypeDescription)
   NODE(parser, OmpDirectiveName)
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index 18b583669421a..079c0d642c32b 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -4406,6 +4406,14 @@ struct OmpDeviceClause {
   std::tuple<MODIFIERS(), ScalarIntExpr> t;
 };
 
+// Ref: [6.0:356-362]
+//
+// device-safesync-clause ->
+//    DEVICE_SAFESYNC [(scalar-logical-const-expr)] // since 6.0
+struct OmpDeviceSafesyncClause {
+  WRAPPER_CLASS_BOILERPLATE(OmpDeviceSafesyncClause, ScalarLogicalConstantExpr);
+};
+
 // Ref: [5.0:180-185], [5.1:210-216], [5.2:275]
 //
 // device-type-clause ->
diff --git a/flang/lib/Lower/OpenMP/Clauses.cpp b/flang/lib/Lower/OpenMP/Clauses.cpp
index 60e569efa964a..c11a3dda7dc41 100644
--- a/flang/lib/Lower/OpenMP/Clauses.cpp
+++ b/flang/lib/Lower/OpenMP/Clauses.cpp
@@ -740,6 +740,18 @@ Device make(const parser::OmpClause::Device &inp,
                  /*DeviceDescription=*/makeExpr(t1, semaCtx)}};
 }
 
+DeviceSafesync make(const parser::OmpClause::DeviceSafesync &inp,
+                    semantics::SemanticsContext &semaCtx) {
+  // inp.v -> std::optional<parser::OmpDeviceSafesyncClause>
+  auto &&maybeRequired = maybeApply(
+      [&](const parser::OmpDeviceSafesyncClause &c) {
+        return makeExpr(c.v, semaCtx);
+      },
+      inp.v);
+
+  return DeviceSafesync{/*Required=*/std::move(maybeRequired)};
+}
+
 DeviceType make(const parser::OmpClause::DeviceType &inp,
                 semantics::SemanticsContext &semaCtx) {
   // inp.v -> parser::OmpDeviceTypeClause
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index 0a70930a0db33..63216384a6582 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -1150,6 +1150,9 @@ TYPE_PARSER( //
             construct<OmpDestroyClause>(Parser<OmpObject>{}))))) ||
     "DEVICE" >> construct<OmpClause>(construct<OmpClause::Device>(
                     parenthesized(Parser<OmpDeviceClause>{}))) ||
+    "DEVICE_SAFESYNC" >>
+        construct<OmpClause>(construct<OmpClause::DeviceSafesync>(
+            maybe(parenthesized(scalarLogicalConstantExpr)))) ||
     "DEVICE_TYPE" >> construct<OmpClause>(construct<OmpClause::DeviceType>(
                          parenthesized(Parser<OmpDeviceTypeClause>{}))) ||
     "DIST_SCHEDULE" >>
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 1c27df18fba20..7b7dfb87763a5 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -1535,6 +1535,7 @@ void OmpStructureChecker::Enter(const parser::OpenMPRequiresConstruct &x) {
           [&](auto &&s) {
             using TypeS = llvm::remove_cvref_t<decltype(s)>;
             if constexpr ( //
+                std::is_same_v<TypeS, parser::OmpClause::DeviceSafesync> ||
                 std::is_same_v<TypeS, parser::OmpClause::DynamicAllocators> ||
                 std::is_same_v<TypeS, parser::OmpClause::ReverseOffload> ||
                 std::is_same_v<TypeS, parser::OmpClause::SelfMaps> ||
@@ -5155,6 +5156,10 @@ void OmpStructureChecker::Enter(
   CheckAllowedRequiresClause(llvm::omp::Clause::OMPC_atomic_default_mem_order);
 }
 
+void OmpStructureChecker::Enter(const parser::OmpClause::DeviceSafesync &x) {
+  CheckAllowedRequiresClause(llvm::omp::Clause::OMPC_device_safesync);
+}
+
 void OmpStructureChecker::Enter(const parser::OmpClause::DynamicAllocators &x) {
   CheckAllowedRequiresClause(llvm::omp::Clause::OMPC_dynamic_allocators);
 }
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
index 7067ed3d99286..db061bdce18ea 100644
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -586,6 +586,7 @@ class OmpAttributeVisitor : DirectiveAttributeVisitor<llvm::omp::Directive> {
               [&](auto &&s) {
                 using TypeS = llvm::remove_cvref_t<decltype(s)>;
                 if constexpr ( //
+                    std::is_same_v<TypeS, OmpClause::DeviceSafesync> ||
                     std::is_same_v<TypeS, OmpClause::DynamicAllocators> ||
                     std::is_same_v<TypeS, OmpClause::ReverseOffload> ||
                     std::is_same_v<TypeS, OmpClause::SelfMaps> ||
diff --git a/llvm/include/llvm/Frontend/OpenMP/ClauseT.h b/llvm/include/llvm/Frontend/OpenMP/ClauseT.h
index 9153dd1c56b7f..09cbb7f9fcf4e 100644
--- a/llvm/include/llvm/Frontend/OpenMP/ClauseT.h
+++ b/llvm/include/llvm/Frontend/OpenMP/ClauseT.h
@@ -541,6 +541,14 @@ struct DeviceT {
   std::tuple<OPT(DeviceModifier), DeviceDescription> t;
 };
 
+// [6.0:362]
+template <typename T, typename I, typename E> //
+struct DeviceSafesyncT {
+  using Requires = E;
+  using WrapperTrait = std::true_type;
+  OPT(Requires) v;
+};
+
 // V5.2: [13.1] `device_type` clause
 template <typename T, typename I, typename E> //
 struct DeviceTypeT {
@@ -1331,14 +1339,15 @@ using WrapperClausesT = std::variant<
     AtomicDefaultMemOrderT<T, I, E>, AtT<T, I, E>, BindT<T, I, E>,
     CollapseT<T, I, E>, ContainsT<T, I, E>, CopyinT<T, I, E>,
     CopyprivateT<T, I, E>, DefaultT<T, I, E>, DestroyT<T, I, E>,
-    DetachT<T, I, E>, DeviceTypeT<T, I, E>, DynamicAllocatorsT<T, I, E>,
-    EnterT<T, I, E>, ExclusiveT<T, I, E>, FailT<T, I, E>, FilterT<T, I, E>,
-    FinalT<T, I, E>, FirstprivateT<T, I, E>, HasDeviceAddrT<T, I, E>,
-    HintT<T, I, E>, HoldsT<T, I, E>, InclusiveT<T, I, E>, IndirectT<T, I, E>,
-    InitializerT<T, I, E>, IsDevicePtrT<T, I, E>, LinkT<T, I, E>,
-    MessageT<T, I, E>, NocontextT<T, I, E>, NontemporalT<T, I, E>,
-    NovariantsT<T, I, E>, NumTeamsT<T, I, E>, NumThreadsT<T, I, E>,
-    OrderedT<T, I, E>, PartialT<T, I, E>, PriorityT<T, I, E>, PrivateT<T, I, E>,
+    DetachT<T, I, E>, DeviceSafesyncT<T, I, E>, DeviceTypeT<T, I, E>,
+    DynamicAllocatorsT<T, I, E>, EnterT<T, I, E>, ExclusiveT<T, I, E>,
+    FailT<T, I, E>, FilterT<T, I, E>, FinalT<T, I, E>, FirstprivateT<T, I, E>,
+    HasDeviceAddrT<T, I, E>, HintT<T, I, E>, HoldsT<T, I, E>,
+    InclusiveT<T, I, E>, IndirectT<T, I, E>, InitializerT<T, I, E>,
+    IsDevicePtrT<T, I, E>, LinkT<T, I, E>, MessageT<T, I, E>,
+    NocontextT<T, I, E>, NontemporalT<T, I, E>, NovariantsT<T, I, E>,
+    NumTeamsT<T, I, E>, NumThreadsT<T, I, E>, OrderedT<T, I, E>,
+    PartialT<T, I, E>, PriorityT<T, I, E>, PrivateT<T, I, E>,
     ProcBindT<T, I, E>, ReverseOffloadT<T, I, E>, SafelenT<T, I, E>,
     SelfMapsT<T, I, E>, SeverityT<T, I, E>, SharedT<T, I, E>, SimdlenT<T, I, E>,
     SizesT<T, I, E>, PermutationT<T, I, E>, ThreadLimitT<T, I, E>,
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
index edcf7a92c2a84..00c43d084b216 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -163,6 +163,10 @@ def OMPC_Device : Clause<[Spelling<"device">]> {
   let clangClass = "OMPDeviceClause";
   let flangClass = "OmpDeviceClause";
 }
+def OMPC_DeviceSafesync : Clause<[Spelling<"device_safesync">]> {
+  let flangClass = "OmpDeviceSafesyncClause";
+  let isValueOptional = true;
+}
 def OMPC_DeviceType : Clause<[Spelling<"device_type">]> {
   let flangClass = "OmpDeviceTypeClause";
 }

kparzysz · 2025-10-15T13:27:27Z

PR stack:

…arzysz/q05-more-requires-clauses

tblah

LGTM but this needs lit tests.

…arzysz/q05-more-requires-clauses

llvm/include/llvm/Frontend/OpenMP/OMP.td

Stylie777

Is there any lowering tests for this?

kparzysz · 2025-10-17T16:10:25Z

This code doesn't do lowering, so no.

Stylie777

LGTM, Thanks

kparzysz added 7 commits October 14, 2025 15:15

[flang][OpenMP] Dump requirement clauses/flags in WithOmpDeclarative

639f10e

format

f353224

fix typo

0ccf7a0

[flang][OpenMP] Frontend support for DEVICE_SAFESYNC

404527f

Add parsing and semantic checks for DEVICE_SAFESYNC clause. No lowering.

kparzysz requested review from Stylie777 and tblah October 15, 2025 13:19

llvmbot added flang Flang issues not falling into any other category flang:fir-hlfir flang:openmp flang:semantics flang:parser clang:openmp OpenMP related changes to Clang labels Oct 15, 2025

kparzysz added 2 commits October 16, 2025 07:29

Merge branch 'main' into users/kparzysz/q04-optional-arg-requires

54dc59f

Merge branch 'users/kparzysz/q04-optional-arg-requires' into users/kp…

cef1c51

…arzysz/q05-more-requires-clauses

tblah reviewed Oct 16, 2025

View reviewed changes

kparzysz added 4 commits October 16, 2025 10:57

Add tests for false argument, and expression folding

44e964f

Use version=60 instead of 61

010814a

bug fix + parser test

a62b328

Merge branch 'users/kparzysz/q04-optional-arg-requires' into users/kp…

9279568

…arzysz/q05-more-requires-clauses

Base automatically changed from users/kparzysz/q04-optional-arg-requires to main October 16, 2025 16:59

Merge branch 'main' into users/kparzysz/q05-more-requires-clauses

1657830

Stylie777 reviewed Oct 17, 2025

View reviewed changes

llvm/include/llvm/Frontend/OpenMP/OMP.td Outdated Show resolved Hide resolved

kparzysz added 2 commits October 17, 2025 08:53

undo unrelated code movement

4c14770

Merge branch 'main' into users/kparzysz/q05-more-requires-clauses

6eb23f9

Stylie777 reviewed Oct 17, 2025

View reviewed changes

Merge branch 'main' into users/kparzysz/q05-more-requires-clauses

a4e51af

Stylie777 approved these changes Oct 20, 2025

View reviewed changes

kparzysz merged commit 3590a91 into main Oct 20, 2025
10 checks passed

kparzysz deleted the users/kparzysz/q05-more-requires-clauses branch October 20, 2025 13:11

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[flang][OpenMP] Frontend support for DEVICE_SAFESYNC #163560

[flang][OpenMP] Frontend support for DEVICE_SAFESYNC #163560

Uh oh!

kparzysz commented Oct 15, 2025

Uh oh!

llvmbot commented Oct 15, 2025 •

edited

Loading

Uh oh!

kparzysz commented Oct 15, 2025

Uh oh!

tblah left a comment

Uh oh!

Uh oh!

Stylie777 left a comment

Uh oh!

kparzysz commented Oct 17, 2025

Uh oh!

Stylie777 left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

[flang][OpenMP] Frontend support for DEVICE_SAFESYNC #163560

[flang][OpenMP] Frontend support for DEVICE_SAFESYNC #163560

Uh oh!

Conversation

kparzysz commented Oct 15, 2025

Uh oh!

llvmbot commented Oct 15, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

kparzysz commented Oct 15, 2025

Uh oh!

tblah left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Stylie777 left a comment

Choose a reason for hiding this comment

Uh oh!

kparzysz commented Oct 17, 2025

Uh oh!

Stylie777 left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

llvmbot commented Oct 15, 2025 •

edited

Loading