[Flang][OpenMP] Add parser support for grainsize and num_tasks clause (#113136)

These clauses are applicable only for the taskloop directive. Since the
directive has a TODO error, skipping the addition of TODOs for these
clauses.

flang/examples/FeatureList/FeatureList.cpp

@@ -483,6 +483,8 @@ public:
   READ_FEATURE(OmpEndCriticalDirective)
   READ_FEATURE(OmpEndLoopDirective)
   READ_FEATURE(OmpEndSectionsDirective)
+  READ_FEATURE(OmpGrainsizeClause)
+  READ_FEATURE(OmpGrainsizeClause::Prescriptiveness)
   READ_FEATURE(OmpIfClause)
   READ_FEATURE(OmpIfClause::DirectiveNameModifier)
   READ_FEATURE(OmpLinearClause)
@@ -494,6 +496,8 @@ public:
   READ_FEATURE(OmpMapClause)
   READ_FEATURE(OmpMapClause::TypeModifier)
   READ_FEATURE(OmpMapClause::Type)
+  READ_FEATURE(OmpNumTasksClause)
+  READ_FEATURE(OmpNumTasksClause::Prescriptiveness)
   READ_FEATURE(OmpObject)
   READ_FEATURE(OmpObjectList)
   READ_FEATURE(OmpOrderClause)

flang/include/flang/Parser/dump-parse-tree.h

@@ -547,6 +547,10 @@ public:
   NODE_ENUM(OmpOrderClause, Type)
   NODE(parser, OmpOrderModifier)
   NODE_ENUM(OmpOrderModifier, Kind)
+  NODE(parser, OmpGrainsizeClause)
+  NODE_ENUM(OmpGrainsizeClause, Prescriptiveness)
+  NODE(parser, OmpNumTasksClause)
+  NODE_ENUM(OmpNumTasksClause, Prescriptiveness)
   NODE(parser, OmpProcBindClause)
   NODE_ENUM(OmpProcBindClause, Type)
   NODE_ENUM(OmpReductionClause, ReductionModifier)

flang/include/flang/Parser/parse-tree.h

@@ -3559,6 +3559,13 @@ struct OmpDependClause {
   std::variant<Source, Sink, InOut> u;
 };
 
+// OMP 5.2 12.6.1 grainsize-clause -> grainsize ([prescriptiveness :] value)
+struct OmpGrainsizeClause {
+  TUPLE_CLASS_BOILERPLATE(OmpGrainsizeClause);
+  ENUM_CLASS(Prescriptiveness, Strict);
+  std::tuple<std::optional<Prescriptiveness>, ScalarIntExpr> t;
+};
+
 // 2.12 if-clause -> IF ([ directive-name-modifier :] scalar-logical-expr)
 struct OmpIfClause {
   TUPLE_CLASS_BOILERPLATE(OmpIfClause);
@@ -3688,6 +3695,13 @@ struct OmpScheduleClause {
       t;
 };
 
+// OMP 5.2 12.6.2 num_tasks-clause -> num_tasks ([prescriptiveness :] value)
+struct OmpNumTasksClause {
+  TUPLE_CLASS_BOILERPLATE(OmpNumTasksClause);
+  ENUM_CLASS(Prescriptiveness, Strict);
+  std::tuple<std::optional<Prescriptiveness>, ScalarIntExpr> t;
+};
+
 // OpenMP Clauses
 struct OmpClause {
   UNION_CLASS_BOILERPLATE(OmpClause);

flang/lib/Lower/OpenMP/Clauses.cpp

@@ -721,10 +721,20 @@ From make(const parser::OmpClause::From &inp,
 // Full: empty
 
 Grainsize make(const parser::OmpClause::Grainsize &inp,
-               semantics::SemanticsContext &semaCtx) {
-  // inp.v -> parser::ScalarIntExpr
-  return Grainsize{{/*Prescriptiveness=*/std::nullopt,
-                    /*GrainSize=*/makeExpr(inp.v, semaCtx)}};
+            semantics::SemanticsContext &semaCtx) {
+  // inp.v -> parser::OmpGrainsizeClause
+  using wrapped = parser::OmpGrainsizeClause;
+
+  CLAUSET_ENUM_CONVERT( //
+      convert, parser::OmpGrainsizeClause::Prescriptiveness, Grainsize::Prescriptiveness,
+      // clang-format off
+      MS(Strict,   Strict)
+      // clang-format on
+  );
+  auto &t0 = std::get<std::optional<wrapped::Prescriptiveness>>(inp.v.t);
+  auto &t1 = std::get<parser::ScalarIntExpr>(inp.v.t);
+  return Grainsize{{/*Prescriptiveness=*/maybeApply(convert, t0),
+                    /*Grainsize=*/makeExpr(t1, semaCtx)}};
 }
 
 HasDeviceAddr make(const parser::OmpClause::HasDeviceAddr &inp,
@@ -971,9 +981,20 @@ Novariants make(const parser::OmpClause::Novariants &inp,
 
 NumTasks make(const parser::OmpClause::NumTasks &inp,
               semantics::SemanticsContext &semaCtx) {
-  // inp.v -> parser::ScalarIntExpr
-  return NumTasks{{/*Prescriptiveness=*/std::nullopt,
-                   /*NumTasks=*/makeExpr(inp.v, semaCtx)}};
+  // inp.v -> parser::OmpNumTasksClause
+  using wrapped = parser::OmpNumTasksClause;
+
+  CLAUSET_ENUM_CONVERT( //
+      convert, parser::OmpNumTasksClause::Prescriptiveness,
+      NumTasks::Prescriptiveness,
+      // clang-format off
+      MS(Strict,   Strict)
+      // clang-format on
+  );
+  auto &t0 = std::get<std::optional<wrapped::Prescriptiveness>>(inp.v.t);
+  auto &t1 = std::get<parser::ScalarIntExpr>(inp.v.t);
+  return NumTasks{{/*Prescriptiveness=*/maybeApply(convert, t0),
+                   /*NumTasks=*/makeExpr(t1, semaCtx)}};
 }
 
 NumTeams make(const parser::OmpClause::NumTeams &inp,

flang/lib/Parser/openmp-parsers.cpp

@@ -408,6 +408,16 @@ TYPE_PARSER(construct<OmpOrderClause>(
     maybe(Parser<OmpOrderModifier>{} / ":"),
     "CONCURRENT" >> pure(OmpOrderClause::Type::Concurrent)))
 
+// OMP 5.2 12.6.1 grainsize([ prescriptiveness :] scalar-integer-expression)
+TYPE_PARSER(construct<OmpGrainsizeClause>(
+    maybe("STRICT" >> pure(OmpGrainsizeClause::Prescriptiveness::Strict) / ":"),
+    scalarIntExpr))
+
+// OMP 5.2 12.6.2 num_tasks([ prescriptiveness :] scalar-integer-expression)
+TYPE_PARSER(construct<OmpNumTasksClause>(
+    maybe("STRICT" >> pure(OmpNumTasksClause::Prescriptiveness::Strict) / ":"),
+    scalarIntExpr))
+
 TYPE_PARSER(
     construct<OmpObject>(designator) || construct<OmpObject>("/" >> name / "/"))
 
@@ -464,7 +474,7 @@ TYPE_PARSER(
     "FROM" >> construct<OmpClause>(construct<OmpClause::From>(
                   parenthesized(Parser<OmpObjectList>{}))) ||
     "GRAINSIZE" >> construct<OmpClause>(construct<OmpClause::Grainsize>(
-                       parenthesized(scalarIntExpr))) ||
+                       parenthesized(Parser<OmpGrainsizeClause>{}))) ||
     "HAS_DEVICE_ADDR" >>
         construct<OmpClause>(construct<OmpClause::HasDeviceAddr>(
             parenthesized(Parser<OmpObjectList>{}))) ||
@@ -491,7 +501,7 @@ TYPE_PARSER(
         construct<OmpClause>(construct<OmpClause::Notinbranch>()) ||
     "NOWAIT" >> construct<OmpClause>(construct<OmpClause::Nowait>()) ||
     "NUM_TASKS" >> construct<OmpClause>(construct<OmpClause::NumTasks>(
-                       parenthesized(scalarIntExpr))) ||
+                       parenthesized(Parser<OmpNumTasksClause>{}))) ||
     "NUM_TEAMS" >> construct<OmpClause>(construct<OmpClause::NumTeams>(
                        parenthesized(scalarIntExpr))) ||
     "NUM_THREADS" >> construct<OmpClause>(construct<OmpClause::NumThreads>(

flang/lib/Parser/unparse.cpp

@@ -2196,6 +2196,16 @@ public:
     Walk(std::get<std::optional<OmpOrderModifier>>(x.t), ":");
     Walk(std::get<OmpOrderClause::Type>(x.t));
   }
+  void Unparse(const OmpGrainsizeClause &x) {
+    Walk(std::get<std::optional<OmpGrainsizeClause::Prescriptiveness>>(x.t),
+        ":");
+    Walk(std::get<ScalarIntExpr>(x.t));
+  }
+  void Unparse(const OmpNumTasksClause &x) {
+    Walk(
+        std::get<std::optional<OmpNumTasksClause::Prescriptiveness>>(x.t), ":");
+    Walk(std::get<ScalarIntExpr>(x.t));
+  }
   void Unparse(const OmpDependSinkVecLength &x) {
     Walk(std::get<DefinedOperator>(x.t));
     Walk(std::get<ScalarIntConstantExpr>(x.t));
@@ -2829,6 +2839,9 @@ public:
   WALK_NESTED_ENUM(OmpCancelType, Type) // OMP cancel-type
   WALK_NESTED_ENUM(OmpOrderClause, Type) // OMP order-type
   WALK_NESTED_ENUM(OmpOrderModifier, Kind) // OMP order-modifier
+  WALK_NESTED_ENUM(
+      OmpGrainsizeClause, Prescriptiveness) // OMP grainsize-modifier
+  WALK_NESTED_ENUM(OmpNumTasksClause, Prescriptiveness) // OMP numtasks-modifier
   WALK_NESTED_ENUM(OmpMapClause, Type) // OMP map-type
   WALK_NESTED_ENUM(OmpMapClause, TypeModifier) // OMP map-type-modifier
 #undef WALK_NESTED_ENUM

flang/lib/Semantics/check-omp-structure.cpp

@@ -2479,12 +2479,14 @@ CHECK_SIMPLE_CLAUSE(Final, OMPC_final)
 CHECK_SIMPLE_CLAUSE(Flush, OMPC_flush)
 CHECK_SIMPLE_CLAUSE(From, OMPC_from)
 CHECK_SIMPLE_CLAUSE(Full, OMPC_full)
+CHECK_SIMPLE_CLAUSE(Grainsize, OMPC_grainsize)
 CHECK_SIMPLE_CLAUSE(Hint, OMPC_hint)
 CHECK_SIMPLE_CLAUSE(Holds, OMPC_holds)
 CHECK_SIMPLE_CLAUSE(InReduction, OMPC_in_reduction)
 CHECK_SIMPLE_CLAUSE(Inclusive, OMPC_inclusive)
 CHECK_SIMPLE_CLAUSE(Match, OMPC_match)
 CHECK_SIMPLE_CLAUSE(Nontemporal, OMPC_nontemporal)
+CHECK_SIMPLE_CLAUSE(NumTasks, OMPC_num_tasks)
 CHECK_SIMPLE_CLAUSE(Order, OMPC_order)
 CHECK_SIMPLE_CLAUSE(Read, OMPC_read)
 CHECK_SIMPLE_CLAUSE(Threadprivate, OMPC_threadprivate)
@@ -2535,8 +2537,6 @@ CHECK_SIMPLE_CLAUSE(OmpxBare, OMPC_ompx_bare)
 CHECK_SIMPLE_CLAUSE(Fail, OMPC_fail)
 CHECK_SIMPLE_CLAUSE(Weak, OMPC_weak)
 
-CHECK_REQ_SCALAR_INT_CLAUSE(Grainsize, OMPC_grainsize)
-CHECK_REQ_SCALAR_INT_CLAUSE(NumTasks, OMPC_num_tasks)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumTeams, OMPC_num_teams)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumThreads, OMPC_num_threads)
 CHECK_REQ_SCALAR_INT_CLAUSE(OmpxDynCgroupMem, OMPC_ompx_dyn_cgroup_mem)

flang/test/Parser/OpenMP/taskloop.f90

@@ -0,0 +1,41 @@
+! RUN: %flang_fc1 -fdebug-unparse -fopenmp %s | FileCheck --ignore-case %s
+! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp %s | FileCheck --check-prefix="PARSE-TREE" %s
+
+subroutine parallel_work
+  integer :: i
+
+!CHECK: !$OMP TASKLOOP  GRAINSIZE(STRICT:500_4)
+!PARSE-TREE: OmpBeginLoopDirective
+!PARSE-TREE-NEXT: OmpLoopDirective -> llvm::omp::Directive = taskloop
+!PARSE-TREE-NEXT: OmpClauseList -> OmpClause -> Grainsize -> OmpGrainsizeClause
+!PARSE-TREE-NEXT: Prescriptiveness = Strict
+!PARSE-TREE-NEXT: Scalar -> Integer -> Expr = '500_4'
+  !$omp taskloop grainsize(strict: 500)
+  do i=1,10000
+    call loop_body(i)
+  end do
+  !$omp end taskloop
+
+!CHECK: !$OMP TASKLOOP  GRAINSIZE(500_4)
+!PARSE-TREE: OmpBeginLoopDirective
+!PARSE-TREE-NEXT: OmpLoopDirective -> llvm::omp::Directive = taskloop
+!PARSE-TREE-NEXT: OmpClauseList -> OmpClause -> Grainsize -> OmpGrainsizeClause
+!PARSE-TREE-NEXT: Scalar -> Integer -> Expr = '500_4'
+  !$omp taskloop grainsize(500)
+  do i=1,10000
+    call loop_body(i)
+  end do
+  !$omp end taskloop
+
+!CHECK: !$OMP TASKLOOP  NUM_TASKS(STRICT:500_4)
+!PARSE-TREE: OmpBeginLoopDirective
+!PARSE-TREE-NEXT: OmpLoopDirective -> llvm::omp::Directive = taskloop
+!PARSE-TREE-NEXT: OmpClauseList -> OmpClause -> NumTasks -> OmpNumTasksClause
+!PARSE-TREE-NEXT: Prescriptiveness = Strict
+!PARSE-TREE-NEXT: Scalar -> Integer -> Expr = '500_4'
+  !$omp taskloop num_tasks(strict: 500)
+  do i=1,10000
+    call loop_body(i)
+  end do
+  !$omp end taskloop
+end subroutine parallel_work

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

@@ -185,10 +185,10 @@ def OMPC_Full: Clause<"full"> {
   let clangClass = "OMPFullClause";
 }
 def OMP_GRAINSIZE_Strict : ClauseVal<"strict", 1, 1> {}
-def OMP_GRAINSIZE_Unknown : ClauseVal<"unkonwn", 2, 0> { let isDefault = 1; }
+def OMP_GRAINSIZE_Unknown : ClauseVal<"unknown", 2, 0> { let isDefault = 1; }
 def OMPC_GrainSize : Clause<"grainsize"> {
   let clangClass = "OMPGrainsizeClause";
-  let flangClass = "ScalarIntExpr";
+  let flangClass = "OmpGrainsizeClause";
   let enumClauseValue = "GrainsizeType";
   let allowedClauseValues = [
     OMP_GRAINSIZE_Strict,
@@ -301,10 +301,10 @@ def OMPC_NoWait : Clause<"nowait"> {
   let clangClass = "OMPNowaitClause";
 }
 def OMP_NUMTASKS_Strict : ClauseVal<"strict", 1, 1> {}
-def OMP_NUMTASKS_Unknown : ClauseVal<"unkonwn", 2, 0> { let isDefault = 1; }
+def OMP_NUMTASKS_Unknown : ClauseVal<"unknown", 2, 0> { let isDefault = 1; }
 def OMPC_NumTasks : Clause<"num_tasks"> {
   let clangClass = "OMPNumTasksClause";
-  let flangClass = "ScalarIntExpr";
+  let flangClass = "OmpNumTasksClause";
   let enumClauseValue = "NumTasksType";
   let allowedClauseValues = [
     OMP_NUMTASKS_Strict,