[OPENMP 4.5] Parsing/sema for 'num_tasks' clause.

OpenMP 4.5 adds directives 'taskloop' and 'taskloop simd'. These directives support clause 'num_tasks'. Patch adds parsing/semantic analysis for this clause.

llvm-svn: 255008

21 files changed, 406 insertions, 12 deletions

diff --git a/clang/include/clang/AST/OpenMPClause.h b/clang/include/clang/AST/OpenMPClause.h
index 869492a4d90..22f6a472138 100644
--- a/clang/include/clang/AST/OpenMPClause.h
+++ b/clang/include/clang/AST/OpenMPClause.h
@@ -2976,6 +2976,58 @@ public:
   }
 };
 
+/// \brief This represents 'num_tasks' clause in the '#pragma omp ...'
+/// directive.
+///
+/// \code
+/// #pragma omp taskloop num_tasks(4)
+/// \endcode
+/// In this example directive '#pragma omp taskloop' has clause 'num_tasks'
+/// with single expression '4'.
+///
+class OMPNumTasksClause : public OMPClause {
+  friend class OMPClauseReader;
+  /// \brief Location of '('.
+  SourceLocation LParenLoc;
+  /// \brief Safe iteration space distance.
+  Stmt *NumTasks;
+
+  /// \brief Set safelen.
+  void setNumTasks(Expr *Size) { NumTasks = Size; }
+
+public:
+  /// \brief Build 'num_tasks' clause.
+  ///
+  /// \param Size Expression associated with this clause.
+  /// \param StartLoc Starting location of the clause.
+  /// \param EndLoc Ending location of the clause.
+  ///
+  OMPNumTasksClause(Expr *Size, SourceLocation StartLoc,
+                    SourceLocation LParenLoc, SourceLocation EndLoc)
+      : OMPClause(OMPC_num_tasks, StartLoc, EndLoc), LParenLoc(LParenLoc),
+        NumTasks(Size) {}
+
+  /// \brief Build an empty clause.
+  ///
+  explicit OMPNumTasksClause()
+      : OMPClause(OMPC_num_tasks, SourceLocation(), SourceLocation()),
+        LParenLoc(SourceLocation()), NumTasks(nullptr) {}
+
+  /// \brief Sets the location of '('.
+  void setLParenLoc(SourceLocation Loc) { LParenLoc = Loc; }
+  /// \brief Returns the location of '('.
+  SourceLocation getLParenLoc() const { return LParenLoc; }
+
+  /// \brief Return safe iteration space distance.
+  Expr *getNumTasks() const { return cast_or_null<Expr>(NumTasks); }
+
+  static bool classof(const OMPClause *T) {
+    return T->getClauseKind() == OMPC_num_tasks;
+  }
+
+  child_range children() { return child_range(&NumTasks, &NumTasks + 1); }
+};
+
 } // end namespace clang
 
 #endif // LLVM_CLANG_AST_OPENMPCLAUSE_H
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index d29c8cfef6f..3eeeca2576a 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2765,6 +2765,13 @@ bool RecursiveASTVisitor<Derived>::VisitOMPGrainsizeClause(
   return true;
 }
 
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPNumTasksClause(
+    OMPNumTasksClause *C) {
+  TRY_TO(TraverseStmt(C->getNumTasks()));
+  return true;
+}
+
 // FIXME: look at the following tricky-seeming exprs to see if we
 // need to recurse on anything.  These are ones that have methods
 // returning decls or qualtypes or nestednamespecifier -- though I'm
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index c4fe9792a32..230f361698e 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7927,6 +7927,10 @@ def err_omp_firstprivate_and_lastprivate_in_distribute : Error<
   "lastprivate variable cannot be firstprivate in '#pragma omp distribute'">;
 def err_omp_firstprivate_distribute_in_teams_reduction : Error<
   "reduction variable in '#pragma omp teams' cannot be firstprivate in '#pragma omp distribute'">;
+def err_omp_grainsize_num_tasks_mutually_exclusive : Error<
+  "'%0' and '%1' clause are mutually exclusive and may not appear on the same directive">;
+def note_omp_previous_grainsize_num_tasks : Note<
+  "'%0' clause is specified here">;
 } // end of OpenMP category
 
 let CategoryName = "Related Result Type Issue" in {
diff --git a/clang/include/clang/Basic/OpenMPKinds.def b/clang/include/clang/Basic/OpenMPKinds.def
index a0ca88e7fe7..befaf7a7870 100644
--- a/clang/include/clang/Basic/OpenMPKinds.def
+++ b/clang/include/clang/Basic/OpenMPKinds.def
@@ -167,6 +167,7 @@ OPENMP_CLAUSE(thread_limit, OMPThreadLimitClause)
 OPENMP_CLAUSE(priority, OMPPriorityClause)
 OPENMP_CLAUSE(grainsize, OMPGrainsizeClause)
 OPENMP_CLAUSE(nogroup, OMPNogroupClause)
+OPENMP_CLAUSE(num_tasks, OMPNumTasksClause)
 
 // Clauses allowed for OpenMP directive 'parallel'.
 OPENMP_PARALLEL_CLAUSE(if)
@@ -357,7 +358,6 @@ OPENMP_MAP_KIND(release)
 OPENMP_MAP_KIND(always)
 
 // Clauses allowed for OpenMP directive 'taskloop'.
-// TODO: add next clauses
 OPENMP_TASKLOOP_CLAUSE(if)
 OPENMP_TASKLOOP_CLAUSE(shared)
 OPENMP_TASKLOOP_CLAUSE(private)
@@ -371,9 +371,9 @@ OPENMP_TASKLOOP_CLAUSE(mergeable)
 OPENMP_TASKLOOP_CLAUSE(priority)
 OPENMP_TASKLOOP_CLAUSE(grainsize)
 OPENMP_TASKLOOP_CLAUSE(nogroup)
+OPENMP_TASKLOOP_CLAUSE(num_tasks)
 
 // Clauses allowed for OpenMP directive 'taskloop simd'.
-// TODO: add next clauses
 OPENMP_TASKLOOP_SIMD_CLAUSE(if)
 OPENMP_TASKLOOP_SIMD_CLAUSE(shared)
 OPENMP_TASKLOOP_SIMD_CLAUSE(private)
@@ -391,6 +391,7 @@ OPENMP_TASKLOOP_SIMD_CLAUSE(safelen)
 OPENMP_TASKLOOP_SIMD_CLAUSE(simdlen)
 OPENMP_TASKLOOP_SIMD_CLAUSE(grainsize)
 OPENMP_TASKLOOP_SIMD_CLAUSE(nogroup)
+OPENMP_TASKLOOP_SIMD_CLAUSE(num_tasks)
 
 // Clauses allowed for OpenMP directive 'distribute'
 OPENMP_DISTRIBUTE_CLAUSE(private)
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index f79f444c8cd..e2f29e4d3e5 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -8012,6 +8012,10 @@ public:
   OMPClause *ActOnOpenMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation EndLoc);
+  /// \brief Called on well-formed 'num_tasks' clause.
+  OMPClause *ActOnOpenMPNumTasksClause(Expr *NumTasks, SourceLocation StartLoc,
+                                       SourceLocation LParenLoc,
+                                       SourceLocation EndLoc);
 
   OMPClause *ActOnOpenMPSimpleClause(OpenMPClauseKind Kind,
                                      unsigned Argument,
diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 2c5ec09addb..a06fc0cf6ee 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -737,6 +737,12 @@ void OMPClausePrinter::VisitOMPGrainsizeClause(OMPGrainsizeClause *Node) {
   OS << ")";
 }
 
+void OMPClausePrinter::VisitOMPNumTasksClause(OMPNumTasksClause *Node) {
+  OS << "num_tasks(";
+  Node->getNumTasks()->printPretty(OS, nullptr, Policy, 0);
+  OS << ")";
+}
+
 template<typename T>
 void OMPClausePrinter::VisitOMPClauseList(T *Node, char StartSym) {
   for (typename T::varlist_iterator I = Node->varlist_begin(),
diff --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
index ca008cecc15..c7fadafba57 100644
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -468,6 +468,9 @@ void OMPClauseProfiler::VisitOMPPriorityClause(const OMPPriorityClause *C) {
 void OMPClauseProfiler::VisitOMPGrainsizeClause(const OMPGrainsizeClause *C) {
   Profiler->VisitStmt(C->getGrainsize());
 }
+void OMPClauseProfiler::VisitOMPNumTasksClause(const OMPNumTasksClause *C) {
+  Profiler->VisitStmt(C->getNumTasks());
+}
 }
 
 void
diff --git a/clang/lib/Basic/OpenMPKinds.cpp b/clang/lib/Basic/OpenMPKinds.cpp
index 7e3156ec2c2..bfd257abe69 100644
--- a/clang/lib/Basic/OpenMPKinds.cpp
+++ b/clang/lib/Basic/OpenMPKinds.cpp
@@ -140,6 +140,7 @@ unsigned clang::getOpenMPSimpleClauseType(OpenMPClauseKind Kind,
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
     break;
   }
   llvm_unreachable("Invalid OpenMP simple clause kind");
@@ -243,6 +244,7 @@ const char *clang::getOpenMPSimpleClauseTypeName(OpenMPClauseKind Kind,
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
     break;
   }
   llvm_unreachable("Invalid OpenMP simple clause kind");
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index c3382859593..356b1de03ac 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -2488,6 +2488,7 @@ static void EmitOMPAtomicExpr(CodeGenFunction &CGF, OpenMPClauseKind Kind,
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
     llvm_unreachable("Clause is not allowed in 'omp atomic'.");
   }
 }
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 76f2e975d47..c3d810da349 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -404,7 +404,7 @@ bool Parser::ParseOpenMPSimpleVarList(OpenMPDirectiveKind Kind,
 ///       update-clause | capture-clause | seq_cst-clause | device-clause |
 ///       simdlen-clause | threads-clause | simd-clause | num_teams-clause |
 ///       thread_limit-clause | priority-clause | grainsize-clause |
-///       nogroup-clause
+///       nogroup-clause | num_tasks-clause
 ///
 OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
                                      OpenMPClauseKind CKind, bool FirstClause) {
@@ -429,6 +429,7 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
   case OMPC_thread_limit:
   case OMPC_priority:
   case OMPC_grainsize:
+  case OMPC_num_tasks:
     // OpenMP [2.5, Restrictions]
     //  At most one num_threads clause can appear on the directive.
     // OpenMP [2.8.1, simd construct, Restrictions]
@@ -447,6 +448,8 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
     // At most one priority clause can appear on the directive.
     // OpenMP [2.9.2, taskloop Construct, Restrictions]
     // At most one grainsize clause can appear on the directive.
+    // OpenMP [2.9.2, taskloop Construct, Restrictions]
+    // At most one num_tasks clause can appear on the directive.
     if (!FirstClause) {
       Diag(Tok, diag::err_omp_more_one_clause)
           << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
@@ -538,7 +541,7 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
 
 /// \brief Parsing of OpenMP clauses with single expressions like 'final',
 /// 'collapse', 'safelen', 'num_threads', 'simdlen', 'num_teams',
-/// 'thread_limit', 'simdlen', 'priority' or 'grainsize'.
+/// 'thread_limit', 'simdlen', 'priority', 'grainsize' or 'num_tasks'.
 ///
 ///    final-clause:
 ///      'final' '(' expression ')'
@@ -561,6 +564,9 @@ OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
 ///    grainsize-clause:
 ///      'grainsize' '(' expression ')'
 ///
+///    num_tasks-clause:
+///      'num_tasks' '(' expression ')'
+///
 OMPClause *Parser::ParseOpenMPSingleExprClause(OpenMPClauseKind Kind) {
   SourceLocation Loc = ConsumeToken();
 
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 20c3c73c94a..c589d0afff2 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -5367,6 +5367,30 @@ StmtResult Sema::ActOnOpenMPCancelDirective(ArrayRef<OMPClause *> Clauses,
                                     CancelRegion);
 }
 
+static bool checkGrainsizeNumTasksClauses(Sema &S,
+                                          ArrayRef<OMPClause *> Clauses) {
+  OMPClause *PrevClause = nullptr;
+  bool ErrorFound = false;
+  for (auto *C : Clauses) {
+    if (C->getClauseKind() == OMPC_grainsize ||
+        C->getClauseKind() == OMPC_num_tasks) {
+      if (!PrevClause)
+        PrevClause = C;
+      else if (PrevClause->getClauseKind() != C->getClauseKind()) {
+        S.Diag(C->getLocStart(),
+               diag::err_omp_grainsize_num_tasks_mutually_exclusive)
+            << getOpenMPClauseName(C->getClauseKind())
+            << getOpenMPClauseName(PrevClause->getClauseKind());
+        S.Diag(PrevClause->getLocStart(),
+               diag::note_omp_previous_grainsize_num_tasks)
+            << getOpenMPClauseName(PrevClause->getClauseKind());
+        ErrorFound = true;
+      }
+    }
+  }
+  return ErrorFound;
+}
+
 StmtResult Sema::ActOnOpenMPTaskLoopDirective(
     ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
     SourceLocation EndLoc,
@@ -5388,6 +5412,12 @@ StmtResult Sema::ActOnOpenMPTaskLoopDirective(
   assert((CurContext->isDependentContext() || B.builtAll()) &&
          "omp for loop exprs were not built");
 
+  // OpenMP, [2.9.2 taskloop Construct, Restrictions]
+  // The grainsize clause and num_tasks clause are mutually exclusive and may
+  // not appear on the same taskloop directive.
+  if (checkGrainsizeNumTasksClauses(*this, Clauses))
+    return StmtError();
+
   getCurFunction()->setHasBranchProtectedScope();
   return OMPTaskLoopDirective::Create(Context, StartLoc, EndLoc,
                                       NestedLoopCount, Clauses, AStmt, B);
@@ -5414,6 +5444,12 @@ StmtResult Sema::ActOnOpenMPTaskLoopSimdDirective(
   assert((CurContext->isDependentContext() || B.builtAll()) &&
          "omp for loop exprs were not built");
 
+  // OpenMP, [2.9.2 taskloop Construct, Restrictions]
+  // The grainsize clause and num_tasks clause are mutually exclusive and may
+  // not appear on the same taskloop directive.
+  if (checkGrainsizeNumTasksClauses(*this, Clauses))
+    return StmtError();
+
   getCurFunction()->setHasBranchProtectedScope();
   return OMPTaskLoopSimdDirective::Create(Context, StartLoc, EndLoc,
                                           NestedLoopCount, Clauses, AStmt, B);
@@ -5484,6 +5520,9 @@ OMPClause *Sema::ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind, Expr *Expr,
   case OMPC_grainsize:
     Res = ActOnOpenMPGrainsizeClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
+  case OMPC_num_tasks:
+    Res = ActOnOpenMPNumTasksClause(Expr, StartLoc, LParenLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_default:
   case OMPC_proc_bind:
@@ -5790,6 +5829,7 @@ OMPClause *Sema::ActOnOpenMPSimpleClause(
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
   }
@@ -5925,6 +5965,7 @@ OMPClause *Sema::ActOnOpenMPSingleExprWithArgClause(
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
   }
@@ -6064,6 +6105,7 @@ OMPClause *Sema::ActOnOpenMPClause(OpenMPClauseKind Kind,
   case OMPC_thread_limit:
   case OMPC_priority:
   case OMPC_grainsize:
+  case OMPC_num_tasks:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
   }
@@ -6203,6 +6245,7 @@ OMPClause *Sema::ActOnOpenMPVarListClause(
   case OMPC_priority:
   case OMPC_grainsize:
   case OMPC_nogroup:
+  case OMPC_num_tasks:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
   }
@@ -8184,3 +8227,20 @@ OMPClause *Sema::ActOnOpenMPGrainsizeClause(Expr *Grainsize,
 
   return new (Context) OMPGrainsizeClause(ValExpr, StartLoc, LParenLoc, EndLoc);
 }
+
+OMPClause *Sema::ActOnOpenMPNumTasksClause(Expr *NumTasks,
+                                           SourceLocation StartLoc,
+                                           SourceLocation LParenLoc,
+                                           SourceLocation EndLoc) {
+  Expr *ValExpr = NumTasks;
+
+  // OpenMP [2.9.2, taskloop Constrcut]
+  // The parameter of the num_tasks clause must be a positive integer
+  // expression.
+  if (!IsNonNegativeIntegerValue(ValExpr, *this, OMPC_num_tasks,
+                                 /*StrictlyPositive=*/true))
+    return nullptr;
+
+  return new (Context) OMPNumTasksClause(ValExpr, StartLoc, LParenLoc, EndLoc);
+}
+
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index d38073dc2cb..39f955b4c1e 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -1711,6 +1711,17 @@ public:
                                                 EndLoc);
   }
 
+  /// \brief Build a new OpenMP 'num_tasks' clause.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  OMPClause *RebuildOMPNumTasksClause(Expr *NumTasks, SourceLocation StartLoc,
+                                      SourceLocation LParenLoc,
+                                      SourceLocation EndLoc) {
+    return getSema().ActOnOpenMPNumTasksClause(NumTasks, StartLoc, LParenLoc,
+                                               EndLoc);
+  }
+
   /// \brief Rebuild the operand to an Objective-C \@synchronized statement.
   ///
   /// By default, performs semantic analysis to build the new statement.
@@ -7822,6 +7833,16 @@ TreeTransform<Derived>::TransformOMPGrainsizeClause(OMPGrainsizeClause *C) {
       E.get(), C->getLocStart(), C->getLParenLoc(), C->getLocEnd());
 }
 
+template <typename Derived>
+OMPClause *
+TreeTransform<Derived>::TransformOMPNumTasksClause(OMPNumTasksClause *C) {
+  ExprResult E = getDerived().TransformExpr(C->getNumTasks());
+  if (E.isInvalid())
+    return nullptr;
+  return getDerived().RebuildOMPNumTasksClause(
+      E.get(), C->getLocStart(), C->getLParenLoc(), C->getLocEnd());
+}
+
 //===----------------------------------------------------------------------===//
 // Expression transformation
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index 02cd25ba99e..9a9ae9bd717 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1865,6 +1865,9 @@ OMPClause *OMPClauseReader::readClause() {
   case OMPC_grainsize:
     C = new (Context) OMPGrainsizeClause();
     break;
+  case OMPC_num_tasks:
+    C = new (Context) OMPNumTasksClause();
+    break;
   }
   Visit(C);
   C->setLocStart(Reader->ReadSourceLocation(Record, Idx));
@@ -2211,6 +2214,11 @@ void OMPClauseReader::VisitOMPGrainsizeClause(OMPGrainsizeClause *C) {
   C->setLParenLoc(Reader->ReadSourceLocation(Record, Idx));
 }
 
+void OMPClauseReader::VisitOMPNumTasksClause(OMPNumTasksClause *C) {
+  C->setNumTasks(Reader->Reader.ReadSubExpr());
+  C->setLParenLoc(Reader->ReadSourceLocation(Record, Idx));
+}
+
 //===----------------------------------------------------------------------===//
 // OpenMP Directives.
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 288febaf0e8..6383fb7b3dd 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -2023,6 +2023,11 @@ void OMPClauseWriter::VisitOMPGrainsizeClause(OMPGrainsizeClause *C) {
   Writer->Writer.AddSourceLocation(C->getLParenLoc(), Record);
 }
 
+void OMPClauseWriter::VisitOMPNumTasksClause(OMPNumTasksClause *C) {
+  Writer->Writer.AddStmt(C->getNumTasks());
+  Writer->Writer.AddSourceLocation(C->getLParenLoc(), Record);
+}
+
 //===----------------------------------------------------------------------===//
 // OpenMP Directives.
 //===----------------------------------------------------------------------===//
diff --git a/clang/test/OpenMP/taskloop_ast_print.cpp b/clang/test/OpenMP/taskloop_ast_print.cpp
index 9f4d6ed0c68..06164ab168d 100644
--- a/clang/test/OpenMP/taskloop_ast_print.cpp
+++ b/clang/test/OpenMP/taskloop_ast_print.cpp
@@ -20,7 +20,7 @@ T tmain(T argc) {
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
 // CHECK-NEXT: a = 2;
 #pragma omp parallel
-#pragma omp taskloop private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) nogroup
+#pragma omp taskloop private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) nogroup num_tasks(N)
   for (int i = 0; i < 2; ++i)
     for (int j = 0; j < 2; ++j)
       for (int j = 0; j < 2; ++j)
@@ -33,7 +33,7 @@ T tmain(T argc) {
           for (int j = 0; j < 2; ++j)
             foo();
   // CHECK-NEXT: #pragma omp parallel
-  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) nogroup
+  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) nogroup num_tasks(N)
   // CHECK-NEXT: for (int i = 0; i < 2; ++i)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
@@ -52,8 +52,8 @@ int main(int argc, char **argv) {
   int b = argc, c, d, e, f, g;
   static int a;
 // CHECK: static int a;
-#pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup
-  // CHECK-NEXT: #pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup
+#pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup num_tasks(argc)
+  // CHECK-NEXT: #pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup num_tasks(argc)
   for (int i = 0; i < 2; ++i)
     a = 2;
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
diff --git a/clang/test/OpenMP/taskloop_grainsize_messages.cpp b/clang/test/OpenMP/taskloop_grainsize_messages.cpp
index aaa10740540..047f925b825 100644
--- a/clang/test/OpenMP/taskloop_grainsize_messages.cpp
+++ b/clang/test/OpenMP/taskloop_grainsize_messages.cpp
@@ -44,6 +44,9 @@ int tmain(T argc, S **argv) {
   #pragma omp taskloop grainsize(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
   for (int i = 0; i < 10; ++i)
     foo();
+  #pragma omp taskloop grainsize(argc) num_tasks(argc) // expected-error {{'num_tasks' and 'grainsize' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'grainsize' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
 
   return 0;
 }
@@ -88,6 +91,9 @@ int main(int argc, char **argv) {
   #pragma omp taskloop grainsize(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
   for (int i = 0; i < 10; ++i)
     foo();
+  #pragma omp taskloop grainsize(argc) num_tasks(argc) // expected-error {{'num_tasks' and 'grainsize' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'grainsize' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
 
   return tmain(argc, argv);
 }
diff --git a/clang/test/OpenMP/taskloop_num_tasks_messages.cpp b/clang/test/OpenMP/taskloop_num_tasks_messages.cpp
new file mode 100644
index 00000000000..94d74eb41eb
--- /dev/null
+++ b/clang/test/OpenMP/taskloop_num_tasks_messages.cpp
@@ -0,0 +1,99 @@
+// RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 %s
+
+void foo() {
+}
+
+bool foobool(int argc) {
+  return argc;
+}
+
+struct S1; // expected-note {{declared here}}
+
+template <class T, class S> // expected-note {{declared here}}
+int tmain(T argc, S **argv) {
+  #pragma omp taskloop num_tasks // expected-error {{expected '(' after 'num_tasks'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc)) // expected-warning {{extra tokens at the end of '#pragma omp taskloop' are ignored}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (foobool(argc)), num_tasks (true) // expected-error {{directive '#pragma omp taskloop' cannot contain more than one 'num_tasks' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (S) // expected-error {{'S' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(0) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(-1) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(argc) grainsize(argc) // expected-error {{'grainsize' and 'num_tasks' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'num_tasks' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  #pragma omp taskloop num_tasks // expected-error {{expected '(' after 'num_tasks'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc)) // expected-warning {{extra tokens at the end of '#pragma omp taskloop' are ignored}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (foobool(argc)), num_tasks (true) // expected-error {{directive '#pragma omp taskloop' cannot contain more than one 'num_tasks' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (S1) // expected-error {{'S1' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks (1 0) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(if(tmain(argc, argv) // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(0)  // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(-1) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop num_tasks(argc) grainsize(argc) // expected-error {{'grainsize' and 'num_tasks' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'num_tasks' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return tmain(argc, argv);
+}
diff --git a/clang/test/OpenMP/taskloop_simd_ast_print.cpp b/clang/test/OpenMP/taskloop_simd_ast_print.cpp
index ff4d7087377..3e3b7e4bec2 100644
--- a/clang/test/OpenMP/taskloop_simd_ast_print.cpp
+++ b/clang/test/OpenMP/taskloop_simd_ast_print.cpp
@@ -21,7 +21,7 @@ T tmain(T argc) {
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
 // CHECK-NEXT: a = 2;
 #pragma omp parallel
-#pragma omp taskloop simd private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) simdlen(N) nogroup
+#pragma omp taskloop simd private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) simdlen(N) nogroup num_tasks(N)
   for (int i = 0; i < 2; ++i)
     for (int j = 0; j < 2; ++j)
       for (int j = 0; j < 2; ++j)
@@ -34,7 +34,7 @@ T tmain(T argc) {
           for (int j = 0; j < 2; ++j)
             foo();
   // CHECK-NEXT: #pragma omp parallel
-  // CHECK-NEXT: #pragma omp taskloop simd private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) simdlen(N) nogroup
+  // CHECK-NEXT: #pragma omp taskloop simd private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) simdlen(N) nogroup num_tasks(N)
   // CHECK-NEXT: for (int i = 0; i < 2; ++i)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
@@ -53,8 +53,8 @@ int main(int argc, char **argv) {
   int b = argc, c, d, e, f, g;
   static int a;
 // CHECK: static int a;
-#pragma omp taskloop simd if(taskloop: a) default(none) shared(a) final(b) priority(5) safelen(8) linear(b), aligned(argv) nogroup
-  // CHECK-NEXT: #pragma omp taskloop simd if(taskloop: a) default(none) shared(a) final(b) priority(5) safelen(8) linear(b) aligned(argv) nogroup
+#pragma omp taskloop simd if(taskloop: a) default(none) shared(a) final(b) priority(5) safelen(8) linear(b), aligned(argv) nogroup num_tasks(argc)
+  // CHECK-NEXT: #pragma omp taskloop simd if(taskloop: a) default(none) shared(a) final(b) priority(5) safelen(8) linear(b) aligned(argv) nogroup num_tasks(argc)
   for (int i = 0; i < 2; ++i)
     a = 2;
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
diff --git a/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp b/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp
index a0df9e91d32..45ccb31824f 100644
--- a/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp
+++ b/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp
@@ -44,6 +44,9 @@ int tmain(T argc, S **argv) {
   #pragma omp taskloop simd grainsize(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
   for (int i = 0; i < 10; ++i)
     foo();
+  #pragma omp taskloop simd grainsize(argc) num_tasks(argc) // expected-error {{'num_tasks' and 'grainsize' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'grainsize' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
 
   return 0;
 }
@@ -88,6 +91,9 @@ int main(int argc, char **argv) {
   #pragma omp taskloop simd grainsize(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
   for (int i = 0; i < 10; ++i)
     foo();
+  #pragma omp taskloop simd grainsize(argc) num_tasks(argc) // expected-error {{'num_tasks' and 'grainsize' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'grainsize' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
 
   return tmain(argc, argv);
 }
diff --git a/clang/test/OpenMP/taskloop_simd_num_tasks_messages.cpp b/clang/test/OpenMP/taskloop_simd_num_tasks_messages.cpp
new file mode 100644
index 00000000000..f26ee79a874
--- /dev/null
+++ b/clang/test/OpenMP/taskloop_simd_num_tasks_messages.cpp
@@ -0,0 +1,99 @@
+// RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 %s
+
+void foo() {
+}
+
+bool foobool(int argc) {
+  return argc;
+}
+
+struct S1; // expected-note {{declared here}}
+
+template <class T, class S> // expected-note {{declared here}}
+int tmain(T argc, S **argv) {
+  #pragma omp taskloop simd num_tasks // expected-error {{expected '(' after 'num_tasks'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc)) // expected-warning {{extra tokens at the end of '#pragma omp taskloop simd' are ignored}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (foobool(argc)), num_tasks (true) // expected-error {{directive '#pragma omp taskloop simd' cannot contain more than one 'num_tasks' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (S) // expected-error {{'S' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(0) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(-1) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(argc) grainsize(argc) // expected-error {{'grainsize' and 'num_tasks' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'num_tasks' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  #pragma omp taskloop simd num_tasks // expected-error {{expected '(' after 'num_tasks'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc)) // expected-warning {{extra tokens at the end of '#pragma omp taskloop simd' are ignored}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (foobool(argc)), num_tasks (true) // expected-error {{directive '#pragma omp taskloop simd' cannot contain more than one 'num_tasks' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (S1) // expected-error {{'S1' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks (1 0) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(if(tmain(argc, argv) // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(0)  // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(-1) // expected-error {{argument to 'num_tasks' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd num_tasks(argc) grainsize(argc) // expected-error {{'grainsize' and 'num_tasks' clause are mutually exclusive and may not appear on the same directive}} expected-note {{'num_tasks' clause is specified here}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return tmain(argc, argv);
+}
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 61caa6a8dce..6bd92c434f2 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -2096,6 +2096,10 @@ void OMPClauseEnqueue::VisitOMPGrainsizeClause(const OMPGrainsizeClause *C) {
   Visitor->AddStmt(C->getGrainsize());
 }
 
+void OMPClauseEnqueue::VisitOMPNumTasksClause(const OMPNumTasksClause *C) {
+  Visitor->AddStmt(C->getNumTasks());
+}
+
 template<typename T>
 void OMPClauseEnqueue::VisitOMPClauseList(T *Node) {
   for (const auto *I : Node->varlists()) {