[Flang][OpenMP] Allow copyprivate and nowait on the directive clauses

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

@@ -1203,6 +1203,64 @@ void OmpStructureChecker::Enter(const parser::OpenMPBlockConstruct &x) {
     deviceConstructFound_ = true;
   }
 
+  if (GetContext().directive == llvm::omp::Directive::OMPD_single) {
+    std::set<Symbol *> singleCopyprivateSyms;
+    std::set<Symbol *> endSingleCopyprivateSyms;
+    bool foundNowait{false};
+    parser::CharBlock NowaitSource;
+
+    auto catchCopyPrivateNowaitClauses = [&](const auto &dir, bool endDir) {
+      for (auto &clause : std::get<parser::OmpClauseList>(dir.t).v) {
+        if (clause.Id() == llvm::omp::Clause::OMPC_copyprivate) {
+          for (const auto &ompObject : GetOmpObjectList(clause)->v) {
+            const auto *name{parser::Unwrap<parser::Name>(ompObject)};
+            if (Symbol * symbol{name->symbol}) {
+              if (singleCopyprivateSyms.count(symbol)) {
+                if (endDir) {
+                  context_.Warn(common::UsageWarning::OpenMPUsage, name->source,
+                      "The COPYPRIVATE clause with '%s' is already used on the SINGLE directive"_warn_en_US,
+                      name->ToString());
+                } else {
+                  context_.Say(name->source,
+                      "'%s' appears in more than one COPYPRIVATE clause on the SINGLE directive"_err_en_US,
+                      name->ToString());
+                }
+              } else if (endSingleCopyprivateSyms.count(symbol)) {
+                context_.Say(name->source,
+                    "'%s' appears in more than one COPYPRIVATE clause on the END SINGLE directive"_err_en_US,
+                    name->ToString());
+              } else {
+                if (endDir) {
+                  endSingleCopyprivateSyms.insert(symbol);
+                } else {
+                  singleCopyprivateSyms.insert(symbol);
+                }
+              }
+            }
+          }
+        } else if (clause.Id() == llvm::omp::Clause::OMPC_nowait) {
+          if (foundNowait) {
+            context_.Say(clause.source,
+                "At most one NOWAIT clause can appear on the SINGLE directive"_err_en_US);
+          } else {
+            foundNowait = !endDir;
+          }
+          if (!NowaitSource.ToString().size()) {
+            NowaitSource = clause.source;
+          }
+        }
+      }
+    };
+    catchCopyPrivateNowaitClauses(beginBlockDir, false);
+    catchCopyPrivateNowaitClauses(endBlockDir, true);
+    unsigned version{context_.langOptions().OpenMPVersion};
+    if (version <= 52 && NowaitSource.ToString().size() &&
+        (singleCopyprivateSyms.size() || endSingleCopyprivateSyms.size())) {
+      context_.Say(NowaitSource,
+          "NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive"_err_en_US);
+    }
+  }
+
   switch (beginDir.v) {
   case llvm::omp::Directive::OMPD_target:
     if (CheckTargetBlockOnlyTeams(block)) {
@@ -2852,12 +2910,6 @@ void OmpStructureChecker::Leave(const parser::OmpClauseList &) {
   // clause
   CheckMultListItems();
 
-  // 2.7.3 Single Construct Restriction
-  if (GetContext().directive == llvm::omp::Directive::OMPD_end_single) {
-    CheckNotAllowedIfClause(
-        llvm::omp::Clause::OMPC_copyprivate, {llvm::omp::Clause::OMPC_nowait});
-  }
-
   auto testThreadprivateVarErr = [&](Symbol sym, parser::Name name,
                                      llvmOmpClause clauseTy) {
     if (sym.test(Symbol::Flag::OmpThreadprivate))
@@ -3481,15 +3533,6 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Private &x) {
 
 void OmpStructureChecker::Enter(const parser::OmpClause::Nowait &x) {
   CheckAllowedClause(llvm::omp::Clause::OMPC_nowait);
-  if (llvm::omp::noWaitClauseNotAllowedSet.test(GetContext().directive)) {
-    context_.Say(GetContext().clauseSource,
-        "%s clause is not allowed on the OMP %s directive,"
-        " use it on OMP END %s directive "_err_en_US,
-        parser::ToUpperCaseLetters(
-            getClauseName(llvm::omp::Clause::OMPC_nowait).str()),
-        parser::ToUpperCaseLetters(GetContext().directiveSource.ToString()),
-        parser::ToUpperCaseLetters(GetContext().directiveSource.ToString()));
-  }
 }
 
 bool OmpStructureChecker::IsDataRefTypeParamInquiry(
@@ -4220,15 +4263,6 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Copyprivate &x) {
   CheckIntentInPointer(symbols, llvm::omp::Clause::OMPC_copyprivate);
   CheckCopyingPolymorphicAllocatable(
       symbols, llvm::omp::Clause::OMPC_copyprivate);
-  if (GetContext().directive == llvm::omp::Directive::OMPD_single) {
-    context_.Say(GetContext().clauseSource,
-        "%s clause is not allowed on the OMP %s directive,"
-        " use it on OMP END %s directive "_err_en_US,
-        parser::ToUpperCaseLetters(
-            getClauseName(llvm::omp::Clause::OMPC_copyprivate).str()),
-        parser::ToUpperCaseLetters(GetContext().directiveSource.ToString()),
-        parser::ToUpperCaseLetters(GetContext().directiveSource.ToString()));
-  }
 }
 
 void OmpStructureChecker::Enter(const parser::OmpClause::Lastprivate &x) {

flang/test/Semantics/OpenMP/clause-validity01.f90

@@ -330,11 +330,12 @@
   !$omp parallel
   b = 1
   !ERROR: LASTPRIVATE clause is not allowed on the SINGLE directive
-  !ERROR: NOWAIT clause is not allowed on the OMP SINGLE directive, use it on OMP END SINGLE directive 
+  !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
   !$omp single private(a) lastprivate(c) nowait
   a = 3.14
-  !ERROR: Clause NOWAIT is not allowed if clause COPYPRIVATE appears on the END SINGLE directive
   !ERROR: COPYPRIVATE variable 'a' may not appear on a PRIVATE or FIRSTPRIVATE clause on a SINGLE construct
+  !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+  !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
   !ERROR: At most one NOWAIT clause can appear on the END SINGLE directive
   !$omp end single copyprivate(a) nowait nowait
   c = 2
@@ -351,7 +352,6 @@
   a = 1.0
   !ERROR: COPYPRIVATE clause is not allowed on the END WORKSHARE directive
   !$omp end workshare nowait copyprivate(a)
-  !ERROR: NOWAIT clause is not allowed on the OMP WORKSHARE directive, use it on OMP END WORKSHARE directive 
   !$omp workshare nowait
   !$omp end workshare
   !$omp end parallel
@@ -420,7 +420,6 @@
   !$omp parallel
   !ERROR: No ORDERED clause with a parameter can be specified on the DO SIMD directive
   !ERROR: NOGROUP clause is not allowed on the DO SIMD directive
-  !ERROR: NOWAIT clause is not allowed on the OMP DO SIMD directive, use it on OMP END DO SIMD directive 
   !$omp do simd ordered(2) NOGROUP nowait
   do i = 1, N
      do j = 1, N

flang/test/Semantics/OpenMP/single03.f90

@@ -0,0 +1,54 @@
+! RUN: %python %S/../test_errors.py %s %flang_fc1 -fopenmp -fopenmp-version=52
+!
+! OpenMP Version 5.2
+!
+! 2.10.2 single Construct
+! Copyprivate and Nowait clauses are allowed in both clause and end clause
+
+subroutine omp_single
+    integer, save :: i
+    integer       :: j
+    i = 10; j = 11
+
+    !ERROR: COPYPRIVATE variable 'i' is not PRIVATE or THREADPRIVATE in outer context
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp single copyprivate(i) nowait
+        print *, "omp single", i
+    !$omp end single
+
+    !$omp parallel private(i)
+        !$omp single copyprivate(i)
+            print *, "omp single", i
+        !$omp end single
+    !$omp end parallel
+
+    !$omp parallel
+        !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+        !$omp single nowait
+            print *, "omp single", i
+        !ERROR: COPYPRIVATE variable 'i' is not PRIVATE or THREADPRIVATE in outer context
+        !$omp end single copyprivate(i)
+
+        !ERROR: COPYPRIVATE variable 'i' is not PRIVATE or THREADPRIVATE in outer context
+        !$omp single copyprivate(i)
+            print *, "omp single", i
+        !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+        !$omp end single nowait
+
+        !ERROR: COPYPRIVATE variable 'j' may not appear on a PRIVATE or FIRSTPRIVATE clause on a SINGLE construct
+        !$omp single private(j) copyprivate(j)
+            print *, "omp single", j
+        !ERROR: COPYPRIVATE variable 'j' may not appear on a PRIVATE or FIRSTPRIVATE clause on a SINGLE construct
+        !WARNING: The COPYPRIVATE clause with 'j' is already used on the SINGLE directive
+        !$omp end single copyprivate(j)
+
+        !$omp single nowait
+            print *, "omp single", j
+        !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+        !$omp end single nowait
+    !$omp end parallel
+
+    !$omp single nowait
+        print *, "omp single", i
+    !$omp end single
+end subroutine omp_single

flang/test/Semantics/OpenMP/single04.f90

@@ -0,0 +1,81 @@
+! RUN: %python %S/../test_errors.py %s %flang_fc1 -fopenmp -fopenmp-version=52
+!
+! OpenMP Version 5.2
+!
+! 2.10.2 single Construct
+! Valid and invalid testcases for copyprivate and nowait clause on the single directive
+
+program single
+    ! Valid testcases
+    !$omp single
+        print *, x
+    !$omp end single
+
+    !$omp single nowait
+        print *, x
+    !$omp end single
+
+    !$omp single copyprivate(x, y, z)
+        print *, x
+    !$omp end single
+
+    !$omp single
+        print *, x
+    !$omp end single copyprivate(x)
+
+    ! Invalid testcases
+    !$omp single
+        print *, x
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp end single copyprivate(x) nowait
+
+    !ERROR: 'x' appears in more than one COPYPRIVATE clause on the SINGLE directive
+    !$omp single copyprivate(x) copyprivate(x)
+        print *, x
+    !$omp end single
+
+    !$omp single
+        print *, x
+    !ERROR: 'x' appears in more than one COPYPRIVATE clause on the END SINGLE directive
+    !$omp end single copyprivate(x) copyprivate(x)
+
+    !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+    !$omp single nowait nowait
+        print *, x
+    !$omp end single
+
+    !$omp single
+        print *, x
+    !ERROR: At most one NOWAIT clause can appear on the END SINGLE directive
+    !$omp end single nowait nowait
+
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp single copyprivate(x) nowait
+        print *, x
+    !WARNING: The COPYPRIVATE clause with 'x' is already used on the SINGLE directive
+    !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+    !$omp end single copyprivate(x) nowait
+
+    !$omp single copyprivate(x)
+        print *, x
+    !WARNING: The COPYPRIVATE clause with 'x' is already used on the SINGLE directive
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp end single copyprivate(x) nowait
+
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp single copyprivate(x, y) nowait
+        print *, x
+    !WARNING: The COPYPRIVATE clause with 'x' is already used on the SINGLE directive
+    !ERROR: 'z' appears in more than one COPYPRIVATE clause on the END SINGLE directive
+    !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+    !$omp end single copyprivate(x, z) copyprivate(z) nowait
+
+    !ERROR: NOWAIT clause must not be used with COPYPRIVATE clause on the SINGLE directive
+    !$omp single copyprivate(x) nowait copyprivate(y) copyprivate(z)
+        print *, x
+    !WARNING: The COPYPRIVATE clause with 'x' is already used on the SINGLE directive
+    !WARNING: The COPYPRIVATE clause with 'y' is already used on the SINGLE directive
+    !WARNING: The COPYPRIVATE clause with 'z' is already used on the SINGLE directive
+    !ERROR: At most one NOWAIT clause can appear on the SINGLE directive
+    !$omp end single copyprivate(x, y, z) nowait
+end program

flang/test/Semantics/OpenMP/threadprivate04.f90

@@ -14,7 +14,6 @@ program main
   !$omp parallel num_threads(x1)
   !$omp end parallel
 
-  !ERROR: COPYPRIVATE clause is not allowed on the OMP SINGLE directive, use it on OMP END SINGLE directive 
   !$omp single copyprivate(x2, /blk1/)
   !$omp end single
 

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

@@ -998,9 +998,11 @@ def OMP_Single : Directive<"single"> {
     VersionedClause<OMPC_Allocate>,
     VersionedClause<OMPC_CopyPrivate>,
     VersionedClause<OMPC_FirstPrivate>,
-    VersionedClause<OMPC_NoWait>,
     VersionedClause<OMPC_Private>,
   ];
+  let allowedOnceClauses = [
+    VersionedClause<OMPC_NoWait>,
+  ];
   let association = AS_Block;
   let category = CA_Executable;
 }