[OPENMP 4.5] parsing/sema support for 'grainsize' clause.
OpenMP 4.5 adds 'taksloop' and 'taskloop simd' directives, which have 'grainsize' clause. Patch adds parsing/sema analysis of this clause.

llvm-svn: 254903
diff --git a/clang/include/clang/AST/OpenMPClause.h b/clang/include/clang/AST/OpenMPClause.h
index 30f4518..869492a 100644
--- a/clang/include/clang/AST/OpenMPClause.h
+++ b/clang/include/clang/AST/OpenMPClause.h
@@ -2893,6 +2893,58 @@
   child_range children() { return child_range(&Priority, &Priority + 1); }
 };
 
+/// \brief This represents 'grainsize' clause in the '#pragma omp ...'
+/// directive.
+///
+/// \code
+/// #pragma omp taskloop grainsize(4)
+/// \endcode
+/// In this example directive '#pragma omp taskloop' has clause 'grainsize'
+/// with single expression '4'.
+///
+class OMPGrainsizeClause : public OMPClause {
+  friend class OMPClauseReader;
+  /// \brief Location of '('.
+  SourceLocation LParenLoc;
+  /// \brief Safe iteration space distance.
+  Stmt *Grainsize;
+
+  /// \brief Set safelen.
+  void setGrainsize(Expr *Size) { Grainsize = Size; }
+
+public:
+  /// \brief Build 'grainsize' clause.
+  ///
+  /// \param Size Expression associated with this clause.
+  /// \param StartLoc Starting location of the clause.
+  /// \param EndLoc Ending location of the clause.
+  ///
+  OMPGrainsizeClause(Expr *Size, SourceLocation StartLoc,
+                     SourceLocation LParenLoc, SourceLocation EndLoc)
+      : OMPClause(OMPC_grainsize, StartLoc, EndLoc), LParenLoc(LParenLoc),
+        Grainsize(Size) {}
+
+  /// \brief Build an empty clause.
+  ///
+  explicit OMPGrainsizeClause()
+      : OMPClause(OMPC_grainsize, SourceLocation(), SourceLocation()),
+        LParenLoc(SourceLocation()), Grainsize(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 *getGrainsize() const { return cast_or_null<Expr>(Grainsize); }
+
+  static bool classof(const OMPClause *T) {
+    return T->getClauseKind() == OMPC_grainsize;
+  }
+
+  child_range children() { return child_range(&Grainsize, &Grainsize + 1); }
+};
+
 /// \brief This represents 'nogroup' clause in the '#pragma omp ...' directive.
 ///
 /// \code
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index 0c856cd..54537b0 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2755,6 +2755,13 @@
   return true;
 }
 
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPGrainsizeClause(
+    OMPGrainsizeClause *C) {
+  TRY_TO(TraverseStmt(C->getGrainsize()));
+  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/OpenMPKinds.def b/clang/include/clang/Basic/OpenMPKinds.def
index e9ce04b..f876008 100644
--- a/clang/include/clang/Basic/OpenMPKinds.def
+++ b/clang/include/clang/Basic/OpenMPKinds.def
@@ -161,6 +161,7 @@
 OPENMP_CLAUSE(num_teams, OMPNumTeamsClause)
 OPENMP_CLAUSE(thread_limit, OMPThreadLimitClause)
 OPENMP_CLAUSE(priority, OMPPriorityClause)
+OPENMP_CLAUSE(grainsize, OMPGrainsizeClause)
 OPENMP_CLAUSE(nogroup, OMPNogroupClause)
 
 // Clauses allowed for OpenMP directive 'parallel'.
@@ -364,6 +365,7 @@
 OPENMP_TASKLOOP_CLAUSE(untied)
 OPENMP_TASKLOOP_CLAUSE(mergeable)
 OPENMP_TASKLOOP_CLAUSE(priority)
+OPENMP_TASKLOOP_CLAUSE(grainsize)
 OPENMP_TASKLOOP_CLAUSE(nogroup)
 
 // Clauses allowed for OpenMP directive 'taskloop simd'.
@@ -383,6 +385,7 @@
 OPENMP_TASKLOOP_SIMD_CLAUSE(aligned)
 OPENMP_TASKLOOP_SIMD_CLAUSE(safelen)
 OPENMP_TASKLOOP_SIMD_CLAUSE(simdlen)
+OPENMP_TASKLOOP_SIMD_CLAUSE(grainsize)
 OPENMP_TASKLOOP_SIMD_CLAUSE(nogroup)
 
 #undef OPENMP_TASKLOOP_SIMD_CLAUSE
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 5f3c1ce..5b21a51 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -8002,6 +8002,10 @@
   ActOnOpenMPOrderedClause(SourceLocation StartLoc, SourceLocation EndLoc,
                            SourceLocation LParenLoc = SourceLocation(),
                            Expr *NumForLoops = nullptr);
+  /// \brief Called on well-formed 'grainsize' clause.
+  OMPClause *ActOnOpenMPGrainsizeClause(Expr *Size, 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 d8802eb1..f680b78 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -731,6 +731,12 @@
   OS << ")";
 }
 
+void OMPClausePrinter::VisitOMPGrainsizeClause(OMPGrainsizeClause *Node) {
+  OS << "grainsize(";
+  Node->getGrainsize()->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 a4255aa..b779b4f 100644
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -465,6 +465,9 @@
 void OMPClauseProfiler::VisitOMPPriorityClause(const OMPPriorityClause *C) {
   Profiler->VisitStmt(C->getPriority());
 }
+void OMPClauseProfiler::VisitOMPGrainsizeClause(const OMPGrainsizeClause *C) {
+  Profiler->VisitStmt(C->getGrainsize());
+}
 }
 
 void
diff --git a/clang/lib/Basic/OpenMPKinds.cpp b/clang/lib/Basic/OpenMPKinds.cpp
index 4a9e7fd..4c4d151 100644
--- a/clang/lib/Basic/OpenMPKinds.cpp
+++ b/clang/lib/Basic/OpenMPKinds.cpp
@@ -138,6 +138,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
     break;
   }
@@ -240,6 +241,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
     break;
   }
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index c80e602..9c6dc62 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -2481,6 +2481,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
     llvm_unreachable("Clause is not allowed in 'omp atomic'.");
   }
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 78d40ef..8f24f5d 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -400,7 +400,8 @@
 ///       mergeable-clause | flush-clause | read-clause | write-clause |
 ///       update-clause | capture-clause | seq_cst-clause | device-clause |
 ///       simdlen-clause | threads-clause | simd-clause | num_teams-clause |
-///       thread_limit-clause | priority-clause | nogroup-clause
+///       thread_limit-clause | priority-clause | grainsize-clause |
+///       nogroup-clause
 ///
 OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
                                      OpenMPClauseKind CKind, bool FirstClause) {
@@ -424,6 +425,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
     // OpenMP [2.5, Restrictions]
     //  At most one num_threads clause can appear on the directive.
     // OpenMP [2.8.1, simd construct, Restrictions]
@@ -440,6 +442,8 @@
     //  At most one thread_limit clause can appear on the directive.
     // OpenMP [2.9.1, task Construct, Restrictions]
     // 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.
     if (!FirstClause) {
       Diag(Tok, diag::err_omp_more_one_clause)
           << getOpenMPDirectiveName(DKind) << getOpenMPClauseName(CKind) << 0;
@@ -531,7 +535,7 @@
 
 /// \brief Parsing of OpenMP clauses with single expressions like 'final',
 /// 'collapse', 'safelen', 'num_threads', 'simdlen', 'num_teams',
-/// 'thread_limit', 'simdlen' or 'priority'.
+/// 'thread_limit', 'simdlen', 'priority' or 'grainsize'.
 ///
 ///    final-clause:
 ///      'final' '(' expression ')'
@@ -551,6 +555,9 @@
 ///    priority-clause:
 ///      'priority' '(' expression ')'
 ///
+///    grainsize-clause:
+///      'grainsize' '(' expression ')'
+///
 OMPClause *Parser::ParseOpenMPSingleExprClause(OpenMPClauseKind Kind) {
   SourceLocation Loc = ConsumeToken();
 
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 125113a..f9efe8e 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -5381,6 +5381,9 @@
   case OMPC_priority:
     Res = ActOnOpenMPPriorityClause(Expr, StartLoc, LParenLoc, EndLoc);
     break;
+  case OMPC_grainsize:
+    Res = ActOnOpenMPGrainsizeClause(Expr, StartLoc, LParenLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_default:
   case OMPC_proc_bind:
@@ -5685,6 +5688,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
@@ -5819,6 +5823,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
@@ -5958,6 +5963,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
   }
@@ -6095,6 +6101,7 @@
   case OMPC_num_teams:
   case OMPC_thread_limit:
   case OMPC_priority:
+  case OMPC_grainsize:
   case OMPC_nogroup:
   case OMPC_unknown:
     llvm_unreachable("Clause is not allowed.");
@@ -8006,3 +8013,19 @@
 
   return new (Context) OMPPriorityClause(ValExpr, StartLoc, LParenLoc, EndLoc);
 }
+
+OMPClause *Sema::ActOnOpenMPGrainsizeClause(Expr *Grainsize,
+                                            SourceLocation StartLoc,
+                                            SourceLocation LParenLoc,
+                                            SourceLocation EndLoc) {
+  Expr *ValExpr = Grainsize;
+
+  // OpenMP [2.9.2, taskloop Constrcut]
+  // The parameter of the grainsize clause must be a positive integer
+  // expression.
+  if (!IsNonNegativeIntegerValue(ValExpr, *this, OMPC_grainsize,
+                                 /*StrictlyPositive=*/true))
+    return nullptr;
+
+  return new (Context) OMPGrainsizeClause(ValExpr, StartLoc, LParenLoc, EndLoc);
+}
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 6d80d03..677b219 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -1700,6 +1700,17 @@
                                                EndLoc);
   }
 
+  /// \brief Build a new OpenMP 'grainsize' clause.
+  ///
+  /// By default, performs semantic analysis to build the new statement.
+  /// Subclasses may override this routine to provide different behavior.
+  OMPClause *RebuildOMPGrainsizeClause(Expr *Grainsize, SourceLocation StartLoc,
+                                       SourceLocation LParenLoc,
+                                       SourceLocation EndLoc) {
+    return getSema().ActOnOpenMPGrainsizeClause(Grainsize, StartLoc, LParenLoc,
+                                                EndLoc);
+  }
+
   /// \brief Rebuild the operand to an Objective-C \@synchronized statement.
   ///
   /// By default, performs semantic analysis to build the new statement.
@@ -7790,6 +7801,16 @@
       E.get(), C->getLocStart(), C->getLParenLoc(), C->getLocEnd());
 }
 
+template <typename Derived>
+OMPClause *
+TreeTransform<Derived>::TransformOMPGrainsizeClause(OMPGrainsizeClause *C) {
+  ExprResult E = getDerived().TransformExpr(C->getGrainsize());
+  if (E.isInvalid())
+    return nullptr;
+  return getDerived().RebuildOMPGrainsizeClause(
+      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 fc1b6b4..95bfa23 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1862,6 +1862,9 @@
   case OMPC_priority:
     C = new (Context) OMPPriorityClause();
     break;
+  case OMPC_grainsize:
+    C = new (Context) OMPGrainsizeClause();
+    break;
   }
   Visit(C);
   C->setLocStart(Reader->ReadSourceLocation(Record, Idx));
@@ -2203,6 +2206,11 @@
   C->setLParenLoc(Reader->ReadSourceLocation(Record, Idx));
 }
 
+void OMPClauseReader::VisitOMPGrainsizeClause(OMPGrainsizeClause *C) {
+  C->setGrainsize(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 d9585e6..21ba243 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -2018,6 +2018,11 @@
   Writer->Writer.AddSourceLocation(C->getLParenLoc(), Record);
 }
 
+void OMPClauseWriter::VisitOMPGrainsizeClause(OMPGrainsizeClause *C) {
+  Writer->Writer.AddStmt(C->getGrainsize());
+  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 28862d8..9f4d6ed 100644
--- a/clang/test/OpenMP/taskloop_ast_print.cpp
+++ b/clang/test/OpenMP/taskloop_ast_print.cpp
@@ -13,8 +13,8 @@
   T b = argc, c, d, e, f, g;
   static T a;
 // CHECK: static T a;
-#pragma omp taskloop if(taskloop: argc > N) default(shared) untied priority(N)
-  // CHECK-NEXT: #pragma omp taskloop if(taskloop: argc > N) default(shared) untied priority(N)
+#pragma omp taskloop if(taskloop: argc > N) default(shared) untied priority(N) grainsize(N)
+  // CHECK-NEXT: #pragma omp taskloop if(taskloop: argc > N) default(shared) untied priority(N) grainsize(N)
   for (int i = 0; i < 2; ++i)
     a = 2;
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
@@ -59,12 +59,12 @@
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
 // CHECK-NEXT: a = 2;
 #pragma omp parallel
-#pragma omp taskloop private(argc, b), firstprivate(argv, c), lastprivate(d, f) collapse(2) shared(g) if(argc) mergeable priority(argc)
+#pragma omp taskloop private(argc, b), firstprivate(argv, c), lastprivate(d, f) collapse(2) shared(g) if(argc) mergeable priority(argc) grainsize(argc)
   for (int i = 0; i < 10; ++i)
     for (int j = 0; j < 10; ++j)
       foo();
   // CHECK-NEXT: #pragma omp parallel
-  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(argv,c) lastprivate(d,f) collapse(2) shared(g) if(argc) mergeable priority(argc)
+  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(argv,c) lastprivate(d,f) collapse(2) shared(g) if(argc) mergeable priority(argc) grainsize(argc)
   // CHECK-NEXT: for (int i = 0; i < 10; ++i)
   // CHECK-NEXT: for (int j = 0; j < 10; ++j)
   // CHECK-NEXT: foo();
diff --git a/clang/test/OpenMP/taskloop_grainsize_messages.cpp b/clang/test/OpenMP/taskloop_grainsize_messages.cpp
new file mode 100644
index 0000000..aaa1074
--- /dev/null
+++ b/clang/test/OpenMP/taskloop_grainsize_messages.cpp
@@ -0,0 +1,93 @@
+// 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 grainsize // expected-error {{expected '(' after 'grainsize'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (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 grainsize (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (foobool(argc)), grainsize (true) // expected-error {{directive '#pragma omp taskloop' cannot contain more than one 'grainsize' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (S) // expected-error {{'S' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize(0) // 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(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  #pragma omp taskloop grainsize // expected-error {{expected '(' after 'grainsize'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (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 grainsize (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (foobool(argc)), grainsize (true) // expected-error {{directive '#pragma omp taskloop' cannot contain more than one 'grainsize' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (S1) // expected-error {{'S1' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize (1 0) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop grainsize(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 grainsize(0)  // 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(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
+  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 46cc35e..ff4d708 100644
--- a/clang/test/OpenMP/taskloop_simd_ast_print.cpp
+++ b/clang/test/OpenMP/taskloop_simd_ast_print.cpp
@@ -14,8 +14,8 @@
   T *ptr;
   static T a;
 // CHECK: static T a;
-#pragma omp taskloop simd if(taskloop: argc > N) default(shared) untied priority(N) safelen(N) linear(c) aligned(ptr)
-  // CHECK-NEXT: #pragma omp taskloop simd if(taskloop: argc > N) default(shared) untied priority(N) safelen(N) linear(c) aligned(ptr)
+#pragma omp taskloop simd if(taskloop: argc > N) default(shared) untied priority(N) safelen(N) linear(c) aligned(ptr) grainsize(N)
+  // CHECK-NEXT: #pragma omp taskloop simd if(taskloop: argc > N) default(shared) untied priority(N) safelen(N) linear(c) aligned(ptr) grainsize(N)
   for (int i = 0; i < 2; ++i)
     a = 2;
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
@@ -60,12 +60,12 @@
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
 // CHECK-NEXT: a = 2;
 #pragma omp parallel
-#pragma omp taskloop simd private(argc, b), firstprivate(argv, c), lastprivate(d, f) collapse(2) shared(g) if(argc) mergeable priority(argc) simdlen(16)
+#pragma omp taskloop simd private(argc, b), firstprivate(argv, c), lastprivate(d, f) collapse(2) shared(g) if(argc) mergeable priority(argc) simdlen(16) grainsize(argc)
   for (int i = 0; i < 10; ++i)
     for (int j = 0; j < 10; ++j)
       foo();
   // CHECK-NEXT: #pragma omp parallel
-  // CHECK-NEXT: #pragma omp taskloop simd private(argc,b) firstprivate(argv,c) lastprivate(d,f) collapse(2) shared(g) if(argc) mergeable priority(argc) simdlen(16)
+  // CHECK-NEXT: #pragma omp taskloop simd private(argc,b) firstprivate(argv,c) lastprivate(d,f) collapse(2) shared(g) if(argc) mergeable priority(argc) simdlen(16) grainsize(argc)
   // CHECK-NEXT: for (int i = 0; i < 10; ++i)
   // CHECK-NEXT: for (int j = 0; j < 10; ++j)
   // CHECK-NEXT: foo();
diff --git a/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp b/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp
new file mode 100644
index 0000000..a0df9e91
--- /dev/null
+++ b/clang/test/OpenMP/taskloop_simd_grainsize_messages.cpp
@@ -0,0 +1,93 @@
+// 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 grainsize // expected-error {{expected '(' after 'grainsize'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (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 grainsize (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (foobool(argc)), grainsize (true) // expected-error {{directive '#pragma omp taskloop simd' cannot contain more than one 'grainsize' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (S) // expected-error {{'S' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize(0) // 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(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  #pragma omp taskloop simd grainsize // expected-error {{expected '(' after 'grainsize'}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize ( // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize () // expected-error {{expected expression}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (argc // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (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 grainsize (argc > 0 ? argv[1][0] : argv[2][argc])
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (foobool(argc)), grainsize (true) // expected-error {{directive '#pragma omp taskloop simd' cannot contain more than one 'grainsize' clause}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (S1) // expected-error {{'S1' does not refer to a value}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (argc argc) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize (1 0) // expected-error {{expected ')'}} expected-note {{to match this '('}}
+  for (int i = 0; i < 10; ++i)
+    foo();
+  #pragma omp taskloop simd grainsize(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 grainsize(0)  // 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(-1) // expected-error {{argument to 'grainsize' clause must be a strictly positive integer value}}
+  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 6bafb7e..3e51aa4 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -2091,6 +2091,10 @@
   Visitor->AddStmt(C->getPriority());
 }
 
+void OMPClauseEnqueue::VisitOMPGrainsizeClause(const OMPGrainsizeClause *C) {
+  Visitor->AddStmt(C->getGrainsize());
+}
+
 template<typename T>
 void OMPClauseEnqueue::VisitOMPClauseList(T *Node) {
   for (const auto *I : Node->varlists()) {