[Frontend][OpenMP] Apply compound construct clause restrictions

This patch removes from the list of allowed clauses for several compound
constructs those that are specifically disallowed by the OpenMP spec. In
particular, the following restrictions are followed:
- (regarding combined constructs) If _directive-name-A_ is `target`, the
`copyin` clause must not be specified.
- (regarding composite constructs) If _directive-name-A_ is `distribute`, the
`ordered` clause must not be specified.

These restrictions are listed in the OpenMP Specification version 5.2, sections
17.4 and 17.5.

Author: skatrak

flang/test/Lower/OpenMP/distribute-parallel-do.f90

@@ -36,21 +36,21 @@ subroutine distribute_parallel_do_dist_schedule()
   !$omp end teams
 end subroutine distribute_parallel_do_dist_schedule
 
-! CHECK-LABEL: func.func @_QPdistribute_parallel_do_ordered(
-subroutine distribute_parallel_do_ordered()
+! CHECK-LABEL: func.func @_QPdistribute_parallel_do_schedule(
+subroutine distribute_parallel_do_schedule()
   !$omp teams
 
   ! CHECK:      omp.parallel private({{.*}}) {
   ! CHECK:      omp.distribute {
-  ! CHECK-NEXT: omp.wsloop ordered(1) {
+  ! CHECK-NEXT: omp.wsloop schedule(runtime) {
   ! CHECK-NEXT: omp.loop_nest
-  !$omp distribute parallel do ordered(1)
+  !$omp distribute parallel do schedule(runtime)
   do index_ = 1, 10
   end do
   !$omp end distribute parallel do
 
   !$omp end teams
-end subroutine distribute_parallel_do_ordered
+end subroutine distribute_parallel_do_schedule
 
 ! CHECK-LABEL: func.func @_QPdistribute_parallel_do_private(
 subroutine distribute_parallel_do_private()

flang/test/Semantics/OpenMP/combined-constructs.f90

@@ -100,6 +100,7 @@ program main
   enddo
   !$omp end target parallel do
 
+  !ERROR: COPYIN clause is not allowed on the TARGET PARALLEL DO directive
   !ERROR: Non-THREADPRIVATE object 'a' in COPYIN clause
   !$omp target parallel do copyin(a)
   do i = 1, N

flang/test/Semantics/OpenMP/ordered03.f90

@@ -52,6 +52,7 @@ subroutine sub1()
   end do
   !$omp end target parallel do
 
+  !ERROR: ORDERED clause is not allowed on the TARGET TEAMS DISTRIBUTE PARALLEL DO directive
   !$omp target teams distribute parallel do ordered(1)
   do i = 1, N
     !ERROR: An ORDERED construct with the DEPEND clause must be closely nested in a worksharing-loop (or parallel worksharing-loop) construct with ORDERED clause with a parameter

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

@@ -1192,7 +1192,6 @@ def OMP_DistributeParallelDo : Directive<"distribute parallel do"> {
     VersionedClause<OMPC_If>,
     VersionedClause<OMPC_NumThreads>,
     VersionedClause<OMPC_Order, 50>,
-    VersionedClause<OMPC_Ordered>,
     VersionedClause<OMPC_ProcBind>,
     VersionedClause<OMPC_Schedule>,
   ];
@@ -1293,7 +1292,6 @@ def OMP_DistributeSimd : Directive<"distribute simd"> {
     VersionedClause<OMPC_If, 50>,
     VersionedClause<OMPC_NumThreads>,
     VersionedClause<OMPC_Order, 50>,
-    VersionedClause<OMPC_Ordered>,
     VersionedClause<OMPC_ProcBind>,
     VersionedClause<OMPC_SafeLen>,
     VersionedClause<OMPC_Schedule>,
@@ -1840,7 +1838,6 @@ def OMP_TargetParallel : Directive<"target parallel"> {
 def OMP_TargetParallelDo : Directive<"target parallel do"> {
   let allowedClauses = [
     VersionedClause<OMPC_Allocator>,
-    VersionedClause<OMPC_Copyin>,
     VersionedClause<OMPC_Default>,
     VersionedClause<OMPC_Depend>,
     VersionedClause<OMPC_FirstPrivate>,
@@ -1977,7 +1974,6 @@ def OMP_TargetParallelForSimd : Directive<"target parallel for simd"> {
 def OMP_target_parallel_loop : Directive<"target parallel loop"> {
   let allowedClauses = [
     VersionedClause<OMPC_Allocate>,
-    VersionedClause<OMPC_Copyin>,
     VersionedClause<OMPC_Depend>,
     VersionedClause<OMPC_Device>,
     VersionedClause<OMPC_FirstPrivate>,
@@ -2106,7 +2102,6 @@ def OMP_TargetTeamsDistributeParallelDo :
     Directive<"target teams distribute parallel do"> {
   let allowedClauses = [
     VersionedClause<OMPC_Allocate>,
-    VersionedClause<OMPC_Copyin>,
     VersionedClause<OMPC_Depend>,
     VersionedClause<OMPC_FirstPrivate>,
     VersionedClause<OMPC_HasDeviceAddr, 51>,
@@ -2115,7 +2110,6 @@ def OMP_TargetTeamsDistributeParallelDo :
     VersionedClause<OMPC_LastPrivate>,
     VersionedClause<OMPC_Linear>,
     VersionedClause<OMPC_Map>,
-    VersionedClause<OMPC_Ordered>,
     VersionedClause<OMPC_Private>,
     VersionedClause<OMPC_Reduction>,
     VersionedClause<OMPC_Shared>,
@@ -2143,7 +2137,6 @@ def OMP_TargetTeamsDistributeParallelDoSimd :
   let allowedClauses = [
     VersionedClause<OMPC_Aligned>,
     VersionedClause<OMPC_Allocate>,
-    VersionedClause<OMPC_Copyin>,
     VersionedClause<OMPC_Depend>,
     VersionedClause<OMPC_FirstPrivate>,
     VersionedClause<OMPC_HasDeviceAddr, 51>,
@@ -2153,7 +2146,6 @@ def OMP_TargetTeamsDistributeParallelDoSimd :
     VersionedClause<OMPC_Linear>,
     VersionedClause<OMPC_Map>,
     VersionedClause<OMPC_NonTemporal>,
-    VersionedClause<OMPC_Ordered>,
     VersionedClause<OMPC_Private>,
     VersionedClause<OMPC_Reduction>,
     VersionedClause<OMPC_Shared>,
@@ -2395,7 +2387,6 @@ def OMP_TeamsDistributeParallelDo :
     VersionedClause<OMPC_NumTeams>,
     VersionedClause<OMPC_NumThreads>,
     VersionedClause<OMPC_Order, 50>,
-    VersionedClause<OMPC_Ordered>,
     VersionedClause<OMPC_ProcBind>,
     VersionedClause<OMPC_Schedule>,
     VersionedClause<OMPC_ThreadLimit>,