OpenMP 5.1 - Support 'seq_cst' clause on 'flush' directive

[soumitra]

Summary

OpenMP 5.1
Add support for the seq_cst clause for the flush directive

[jdoerfert]

I think this contains two distinct changes. Please split.

[soumitra]

The previous patch had unrelated changes inadvertently. Corrected.

clang/include/clang/AST/OpenMPClause.h

     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   static bool classof(const OMPClause *T) {
     return T->getClauseKind() == llvm::omp::OMPC_compare;
   }
 };
 
-/// This represents 'seq_cst' clause in the '#pragma omp atomic'
-/// directive.
+/// This represents 'seq_cst' clause in the '#pragma omp atomic|flush'
+/// directives.
 ///
 /// \code
 /// #pragma omp atomic seq_cst
 /// \endcode
 /// In this example directive '#pragma omp atomic' has 'seq_cst' clause.
 class OMPSeqCstClause : public OMPClause {
 public:
   /// Build 'seq_cst' clause.

clang/include/clang/Basic/DiagnosticSemaKinds.td

 def note_omp_atomic_compare: Note<
   "%select{expected compound statement|expected exactly one expression statement|expected assignment statement|expected conditional operator|expect result value to be at false expression|"
   "expect binary operator in conditional expression|expect '<', '>' or '==' as order operator|expect comparison in a form of 'x == e', 'e == x', 'x ordop expr', or 'expr ordop x'|"
   "expect lvalue for result value|expect scalar value|expect integer value|unexpected 'else' statement|expect '==' operator|expect an assignment statement 'v = x'|"
   "expect a 'if' statement|expect no more than two statements|expect a compound statement|expect 'else' statement|expect a form 'r = x == e; if (r) ...'}0">;
 def err_omp_atomic_several_clauses : Error<
   "directive '#pragma omp atomic' cannot contain more than one 'read', 'write', 'update', 'capture', or 'compare' clause">;
 def err_omp_several_mem_order_clauses : Error<
-  "directive '#pragma omp %0' cannot contain more than one %select{'seq_cst', 'relaxed', |}1'acq_rel', 'acquire' or 'release' clause">;
+  "directive '#pragma omp %0' cannot contain more than one %select{'seq_cst', 'relaxed', |}1'seq_cst', 'acq_rel', 'acquire' or 'release' clause">;
 def err_omp_atomic_incompatible_mem_order_clause : Error<
   "directive '#pragma omp atomic%select{ %0|}1' cannot be used with '%2' clause">;
 def note_omp_previous_mem_order_clause : Note<
   "'%0' clause used here">;
 def err_omp_target_contains_not_only_teams : Error<
   "target construct with nested teams region contains statements outside of the teams construct">;
 def note_omp_nested_teams_construct_here : Note<
   "nested teams construct here">;

clang/lib/Sema/SemaOpenMP.cpp

     else
       OrderClause = C;
   }
   OpenMPClauseKind MemOrderKind = OMPC_unknown;
   SourceLocation MemOrderLoc;
   for (const OMPClause *C : Clauses) {
     if (C->getClauseKind() == OMPC_acq_rel ||
         C->getClauseKind() == OMPC_acquire ||
-        C->getClauseKind() == OMPC_release) {
+        C->getClauseKind() == OMPC_release ||
+        C->getClauseKind() == OMPC_seq_cst /*OpenMP 5.1*/) {
       if (MemOrderKind != OMPC_unknown) {
         Diag(C->getBeginLoc(), diag::err_omp_several_mem_order_clauses)
             << getOpenMPDirectiveName(OMPD_flush) << 1
             << SourceRange(C->getBeginLoc(), C->getEndLoc());
         Diag(MemOrderLoc, diag::note_omp_previous_mem_order_clause)
             << getOpenMPClauseName(MemOrderKind);
       } else {
         MemOrderKind = C->getClauseKind();

clang/test/OpenMP/flush_ast_print.cpp

-// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=50 -ast-print %s | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -fopenmp-version=50 -x c++ -std=c++11 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -fopenmp-version=50 -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
-
-// RUN: %clang_cc1 -verify -fopenmp-simd -fopenmp-version=50 -ast-print %s | FileCheck %s
-// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=50 -x c++ -std=c++11 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=50 -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -ast-print %s | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -x c++ -std=c++11 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
+
+// RUN: %clang_cc1 -verify -fopenmp-simd -fopenmp-version=51 -ast-print %s | FileCheck %s
+// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=51 -x c++ -std=c++11 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=51 -std=c++11 -include-pch %t -fsyntax-only -verify %s -ast-print | FileCheck %s
 // expected-no-diagnostics
 
 #ifndef HEADER
 #define HEADER
 
 void foo() {}
 
 template <class T>
 T tmain(T argc) {
   static T a;
 #pragma omp flush
 #pragma omp flush acq_rel
 #pragma omp flush acquire
 #pragma omp flush release
+#pragma omp flush seq_cst
 #pragma omp flush(a)
   return a + argc;
 }
 // CHECK:      static T a;
 // CHECK-NEXT: #pragma omp flush{{$}}
 // CHECK-NEXT: #pragma omp flush acq_rel{{$}}
 // CHECK-NEXT: #pragma omp flush acquire{{$}}
 // CHECK-NEXT: #pragma omp flush release{{$}}
+// CHECK-NEXT: #pragma omp flush seq_cst{{$}}
 // CHECK-NEXT: #pragma omp flush (a)
 // CHECK:      static int a;
 // CHECK-NEXT: #pragma omp flush
 // CHECK-NEXT: #pragma omp flush acq_rel{{$}}
 // CHECK-NEXT: #pragma omp flush acquire{{$}}
 // CHECK-NEXT: #pragma omp flush release{{$}}
+// CHECK-NEXT: #pragma omp flush seq_cst{{$}}
 // CHECK-NEXT: #pragma omp flush (a)
 // CHECK:      static char a;
 // CHECK-NEXT: #pragma omp flush
 // CHECK-NEXT: #pragma omp flush acq_rel{{$}}
 // CHECK-NEXT: #pragma omp flush acquire{{$}}
 // CHECK-NEXT: #pragma omp flush release{{$}}
+// CHECK-NEXT: #pragma omp flush seq_cst{{$}}
 // CHECK-NEXT: #pragma omp flush (a)
 
 int main(int argc, char **argv) {
   static int a;
 // CHECK: static int a;
 #pragma omp flush
 #pragma omp flush acq_rel
 #pragma omp flush acquire
 #pragma omp flush release
+#pragma omp flush seq_cst
 #pragma omp flush(a)
 // CHECK-NEXT: #pragma omp flush
 // CHECK-NEXT: #pragma omp flush acq_rel
 // CHECK-NEXT: #pragma omp flush acquire{{$}}
 // CHECK-NEXT: #pragma omp flush release
+// CHECK-NEXT: #pragma omp flush seq_cst
 // CHECK-NEXT: #pragma omp flush (a)
   return tmain(argc) + tmain(argv[0][0]) + a;
 }
 
 #endif

clang/test/OpenMP/flush_codegen.cpp

-// RUN: %clang_cc1 -verify -fopenmp -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
-// RUN: %clang_cc1 -verify -fopenmp -fopenmp-enable-irbuilder -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -fopenmp-enable-irbuilder -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -fopenmp-enable-irbuilder -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
-
-// RUN: %clang_cc1 -verify -fopenmp-simd -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck --check-prefix SIMD-ONLY0 %s
-// RUN: %clang_cc1 -fopenmp-simd -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp-simd -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck --check-prefix SIMD-ONLY0 %s
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 -fopenmp-enable-irbuilder -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -fopenmp-enable-irbuilder -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -fopenmp-version=51 -fopenmp-enable-irbuilder -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+
+// RUN: %clang_cc1 -verify -fopenmp-simd -fopenmp-version=51 -x c++ -emit-llvm %s -fexceptions -fcxx-exceptions -o - | FileCheck --check-prefix SIMD-ONLY0 %s
+// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=51 -x c++ -std=c++11 -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp-simd -fopenmp-version=51 -x c++ -triple x86_64-unknown-unknown -fexceptions -fcxx-exceptions -debug-info-kind=limited -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck --check-prefix SIMD-ONLY0 %s
 // SIMD-ONLY0-NOT: {{__kmpc|__tgt}}
 // expected-no-diagnostics
 #ifndef HEADER
 #define HEADER
 
 template <class T>
 T tmain(T argc) {
   static T a;
 #pragma omp flush
 #pragma omp flush acq_rel
 #pragma omp flush acquire
 #pragma omp flush release
+#pragma omp flush seq_cst
 #pragma omp flush(a)
   return a + argc;
 }
 
 // CHECK-LABEL: @main
 int main() {
   static int a;
 #pragma omp flush
 #pragma omp flush acq_rel
 #pragma omp flush acquire
 #pragma omp flush release
+#pragma omp flush seq_cst
 #pragma omp flush(a)
   // CHECK: call {{.*}}void @__kmpc_flush(%{{.+}}* {{(@|%).+}})
   // CHECK: call {{.*}}void @__kmpc_flush(%{{.+}}* {{(@|%).+}})
   // CHECK: call {{.*}}void @__kmpc_flush(%{{.+}}* {{(@|%).+}})
   // CHECK: call {{.*}}void @__kmpc_flush(%{{.+}}* {{(@|%).+}})
   // CHECK: call {{.*}}void @__kmpc_flush(%{{.+}}* {{(@|%).+}})
   return tmain(a);
   // CHECK: call {{.*}} [[TMAIN:@.+]](

clang/test/OpenMP/flush_messages.cpp

 // RUN: %clang_cc1 -verify=expected,omp45 -fopenmp -fopenmp-version=45 -ferror-limit 100 %s -Wuninitialized
-// RUN: %clang_cc1 -verify=expected,omp50 -fopenmp -ferror-limit 100 %s -Wuninitialized
+// RUN: %clang_cc1 -verify=expected,omp51 -fopenmp -ferror-limit 100 %s -Wuninitialized
 
 // RUN: %clang_cc1 -verify=expected,omp45 -fopenmp-simd -fopenmp-version=45 -ferror-limit 100 %s -Wuninitialized
-// RUN: %clang_cc1 -verify=expected,omp50 -fopenmp-simd -ferror-limit 100 %s -Wuninitialized
+// RUN: %clang_cc1 -verify=expected,omp51 -fopenmp-simd -ferror-limit 100 %s -Wuninitialized
 
 struct S1 { // expected-note 2 {{declared here}}
   int a;
 };
 
 template <class T>
 T tmain(T argc) {
 #pragma omp flush allocate(argc) // expected-error {{unexpected OpenMP clause 'allocate' in directive '#pragma omp flush'}}

 #pragma omp parallel flush(argc) // expected-warning {{extra tokens at the end of '#pragma omp parallel' are ignored}}
   ;
 #pragma omp flush seq_cst // expected-error {{unexpected OpenMP clause 'seq_cst' in directive '#pragma omp flush'}}
 #pragma omp flush acq_rel // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}}
 #pragma omp flush acquire // omp45-error {{unexpected OpenMP clause 'acquire' in directive '#pragma omp flush'}}
 #pragma omp flush release // omp45-error {{unexpected OpenMP clause 'release' in directive '#pragma omp flush'}}
 #pragma omp flush relaxed // expected-error {{unexpected OpenMP clause 'relaxed' in directive '#pragma omp flush'}}
 #pragma omp flush seq_cst // expected-error {{unexpected OpenMP clause 'seq_cst' in directive '#pragma omp flush'}}
-#pragma omp flush acq_rel acquire // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}} omp45-error {{unexpected OpenMP clause 'acquire' in directive '#pragma omp flush'}} omp50-error {{directive '#pragma omp flush' cannot contain more than one 'acq_rel', 'acquire' or 'release' clause}} omp50-note {{'acq_rel' clause used here}}
-#pragma omp flush release acquire // omp45-error {{unexpected OpenMP clause 'release' in directive '#pragma omp flush'}} omp45-error {{unexpected OpenMP clause 'acquire' in directive '#pragma omp flush'}} omp50-error {{directive '#pragma omp flush' cannot contain more than one 'acq_rel', 'acquire' or 'release' clause}} omp50-note {{'release' clause used here}}
+#pragma omp flush acq_rel acquire // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}} omp45-error {{unexpected OpenMP clause 'acquire' in directive '#pragma omp flush'}} omp50-error {{directive '#pragma omp flush' cannot contain more than one 'seq_cst', 'acq_rel', 'acquire' or 'release' clause}} omp50-note {{'acq_rel' clause used here}} omp51-error {{directive '#pragma omp flush' cannot contain more than one 'seq_cst', 'acq_rel', 'acquire' or 'release' clause}} omp51-note {{'acq_rel' clause used here}}
+
+#pragma omp flush release acquire // omp45-error {{unexpected OpenMP clause 'release' in directive '#pragma omp flush'}} omp45-error {{unexpected OpenMP clause 'acquire' in directive '#pragma omp flush'}} omp50-error {{directive '#pragma omp flush' cannot contain more than one 'seq_cst', 'acq_rel', 'acquire' or 'release' clause}} omp50-note {{'release' clause used here}} omp51-error {{directive '#pragma omp flush' cannot contain more than one 'seq_cst', 'acq_rel', 'acquire' or 'release' clause}} omp51-note {{'release' clause used here}}
+
 #pragma omp flush acq_rel (argc) // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}} expected-warning {{extra tokens at the end of '#pragma omp flush' are ignored}}
-#pragma omp flush(argc) acq_rel // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}} omp50-error {{'flush' directive with memory order clause 'acq_rel' cannot have the list}} omp50-note {{memory order clause 'acq_rel' is specified here}}
+#pragma omp flush(argc) acq_rel // omp45-error {{unexpected OpenMP clause 'acq_rel' in directive '#pragma omp flush'}} omp50-error {{'flush' directive with memory order clause 'acq_rel' cannot have the list}} omp50-note {{memory order clause 'acq_rel' is specified here}} omp51-error {{'flush' directive with memory order clause 'acq_rel' cannot have the list}} omp51-note {{memory order clause 'acq_rel' is specified here}}
+
   return tmain(argc);
 }

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

let allowedClauses = [
     VersionedClause<OMPC_Allocate, 50>
   ];
 }
 def OMP_Flush : Directive<"flush"> {
   let allowedOnceClauses = [
     VersionedClause<OMPC_AcqRel, 50>,
     VersionedClause<OMPC_Acquire, 50>,
     VersionedClause<OMPC_Release, 50>,
+    VersionedClause<OMPC_SeqCst, 51>,
     // TODO This should ne `none` instead. Comment carried over from
     // OMPKinds.def.
     VersionedClause<OMPC_Flush>
   ];
 }
 def OMP_Ordered : Directive<"ordered"> {
   let allowedClauses = [
     VersionedClause<OMPC_Depend>