diff --git a/flang/lib/Semantics/check-omp-structure.h b/flang/lib/Semantics/check-omp-structure.h
--- a/flang/lib/Semantics/check-omp-structure.h
+++ b/flang/lib/Semantics/check-omp-structure.h
@@ -155,8 +155,10 @@
   void Enter(const parser::OmpClause::Reduction &);
   void Enter(const parser::OmpClause::Safelen &);
   void Enter(const parser::OmpClause::Shared &);
+  void Enter(const parser::OmpClause::Simd &);
   void Enter(const parser::OmpClause::Simdlen &);
   void Enter(const parser::OmpClause::TaskReduction &);
+  void Enter(const parser::OmpClause::Threads &);
   void Enter(const parser::OmpClause::ThreadLimit &);
   void Enter(const parser::OmpClause::To &);
   void Enter(const parser::OmpClause::Link &);
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -433,6 +433,8 @@
 CHECK_SIMPLE_CLAUSE(Hint, OMPC_hint)
 CHECK_SIMPLE_CLAUSE(ProcBind, OMPC_proc_bind)
 CHECK_SIMPLE_CLAUSE(DistSchedule, OMPC_dist_schedule)
+CHECK_SIMPLE_CLAUSE(Simd, OMPC_simd)
+CHECK_SIMPLE_CLAUSE(Threads, OMPC_threads)
 
 CHECK_REQ_SCALAR_INT_CLAUSE(Allocator, OMPC_allocator)
 CHECK_REQ_SCALAR_INT_CLAUSE(Grainsize, OMPC_grainsize)
diff --git a/flang/lib/Semantics/resolve-directives.cpp b/flang/lib/Semantics/resolve-directives.cpp
--- a/flang/lib/Semantics/resolve-directives.cpp
+++ b/flang/lib/Semantics/resolve-directives.cpp
@@ -247,6 +247,9 @@
   bool Pre(const parser::OpenMPBlockConstruct &);
   void Post(const parser::OpenMPBlockConstruct &);
 
+  bool Pre(const parser::OpenMPSimpleStandaloneConstruct &);
+  void Post(const parser::OpenMPSimpleStandaloneConstruct &) { PopContext(); }
+
   void Post(const parser::OmpBeginBlockDirective &) {
     GetContext().withinConstruct = true;
   }
@@ -321,6 +324,20 @@
     ResolveOmpNameList(alignedNameList, Symbol::Flag::OmpAligned);
     return false;
   }
+  bool Pre(const parser::OmpDependClause &x) {
+    if (const auto *dependSink{
+            std::get_if<parser::OmpDependClause::Sink>(&x.u)}) {
+      const auto &dependSinkVec{dependSink->v};
+      for (const auto &dependSinkElement : dependSinkVec) {
+        const auto &name{std::get<parser::Name>(dependSinkElement.t)};
+        if (!ResolveName(&name)) {
+          context_.Say(
+              name.source, "No type declared for '%s'"_err_en_US, name.source);
+        }
+      }
+    }
+    return false;
+  }
   void Post(const parser::Name &);
 
   const parser::OmpClause *associatedClause{nullptr};
@@ -874,6 +891,27 @@
   PopContext();
 }
 
+bool OmpAttributeVisitor::Pre(
+    const parser::OpenMPSimpleStandaloneConstruct &x) {
+  const auto &standaloneDir{
+      std::get<parser::OmpSimpleStandaloneDirective>(x.t)};
+  switch (standaloneDir.v) {
+  case llvm::omp::Directive::OMPD_barrier:
+  case llvm::omp::Directive::OMPD_ordered:
+  case llvm::omp::Directive::OMPD_target_enter_data:
+  case llvm::omp::Directive::OMPD_target_exit_data:
+  case llvm::omp::Directive::OMPD_target_update:
+  case llvm::omp::Directive::OMPD_taskwait:
+  case llvm::omp::Directive::OMPD_taskyield:
+    PushContext(standaloneDir.source, standaloneDir.v);
+    break;
+  default:
+    break;
+  }
+  ClearDataSharingAttributeObjects();
+  return true;
+}
+
 bool OmpAttributeVisitor::Pre(const parser::OpenMPLoopConstruct &x) {
   const auto &beginLoopDir{std::get<parser::OmpBeginLoopDirective>(x.t)};
   const auto &beginDir{std::get<parser::OmpLoopDirective>(beginLoopDir.t)};
diff --git a/flang/test/Semantics/omp-clause-validity01.f90 b/flang/test/Semantics/omp-clause-validity01.f90
--- a/flang/test/Semantics/omp-clause-validity01.f90
+++ b/flang/test/Semantics/omp-clause-validity01.f90
@@ -477,14 +477,22 @@
   !$omp barrier
   !$omp taskwait
   !$omp taskwait depend(source)
-  !ERROR: Internal: no symbol found for 'i'
   !$omp taskwait depend(sink:i-1)
   ! !$omp target enter data map(to:arrayA) map(alloc:arrayB)
   ! !$omp target update from(arrayA) to(arrayB)
   ! !$omp target exit data map(from:arrayA) map(delete:arrayB)
   !$omp ordered depend(source)
-  !ERROR: Internal: no symbol found for 'i'
   !$omp ordered depend(sink:i-1)
+  !ERROR: No type declared for 'undecvar'
+  !$omp ordered depend(sink:undecvar-1)
+  !ERROR: At most one DEPEND clause can appear on the ORDERED directive
+  !$omp ordered depend(source) depend(source)
+  !ERROR: At most one THREADS clause can appear on the ORDERED directive
+  !$omp ordered threads threads
+  !$omp end ordered
+  !ERROR: At most one SIMD clause can appear on the ORDERED directive
+  !$omp ordered simd simd
+  !$omp end ordered
   !$omp flush (c)
   !$omp flush acq_rel
   !$omp flush release
@@ -501,10 +509,8 @@
 
 ! 2.13.2 critical Construct
 
-  !ERROR: Internal: no symbol found for 'first'
   !$omp critical (first)
   a = 3.14
-  !ERROR: Internal: no symbol found for 'first'
   !$omp end critical (first)
 
 ! 2.9.1 task-clause -> if-clause |
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -455,7 +455,7 @@
   ];
 }
 def OMP_Ordered : Directive<"ordered"> {
-  let allowedClauses = [
+  let allowedOnceClauses = [
     VersionedClause<OMPC_Threads>,
     VersionedClause<OMPC_Simd>,
     VersionedClause<OMPC_Depend>