openmp: Diagnose using grainsize+num_tasks clauses together [PR115103]

I've noticed that while we diagnose many other OpenMP exclusive clauses,
we don't diagnose grainsize together with num_tasks on taskloop construct
in all of C, C++ and Fortran (the implementation simply ignored grainsize
in that case) and for Fortran also don't diagnose mixing nogroup clause
with reduction clause(s).

Fixed thusly.

2024-05-15  Jakub Jelinek  <jakub@redhat.com>

	PR c/115103
gcc/c/
	* c-typeck.cc (c_finish_omp_clauses): Diagnose grainsize
	used together with num_tasks.
gcc/cp/
	* semantics.cc (finish_omp_clauses): Diagnose grainsize
	used together with num_tasks.
gcc/fortran/
	* openmp.cc (resolve_omp_clauses): Diagnose grainsize
	used together with num_tasks or nogroup used together with
	reduction.
gcc/testsuite/
	* c-c++-common/gomp/clause-dups-1.c: Add 2 further expected errors.
	* gfortran.dg/gomp/pr115103.f90: New test.

5 files changed, 59 insertions, 4 deletions

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 4567b11..7ecca9f 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -14722,6 +14722,8 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
   tree *detach_seen = NULL;
   bool linear_variable_step_check = false;
   tree *nowait_clause = NULL;
+  tree *grainsize_seen = NULL;
+  bool num_tasks_seen = false;
   tree ordered_clause = NULL_TREE;
   tree schedule_clause = NULL_TREE;
   bool oacc_async = false;
@@ -16021,8 +16023,6 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	case OMP_CLAUSE_PROC_BIND:
 	case OMP_CLAUSE_DEVICE_TYPE:
 	case OMP_CLAUSE_PRIORITY:
-	case OMP_CLAUSE_GRAINSIZE:
-	case OMP_CLAUSE_NUM_TASKS:
 	case OMP_CLAUSE_THREADS:
 	case OMP_CLAUSE_SIMD:
 	case OMP_CLAUSE_HINT:
@@ -16048,6 +16048,16 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  pc = &OMP_CLAUSE_CHAIN (c);
 	  continue;
 
+	case OMP_CLAUSE_GRAINSIZE:
+	  grainsize_seen = pc;
+	  pc = &OMP_CLAUSE_CHAIN (c);
+	  continue;
+
+	case OMP_CLAUSE_NUM_TASKS:
+	  num_tasks_seen = true;
+	  pc = &OMP_CLAUSE_CHAIN (c);
+	  continue;
+
 	case OMP_CLAUSE_MERGEABLE:
 	  mergeable_seen = true;
 	  pc = &OMP_CLAUSE_CHAIN (c);
@@ -16333,6 +16343,14 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
       *nogroup_seen = OMP_CLAUSE_CHAIN (*nogroup_seen);
     }
 
+  if (grainsize_seen && num_tasks_seen)
+    {
+      error_at (OMP_CLAUSE_LOCATION (*grainsize_seen),
+		"%<grainsize%> clause must not be used together with "
+		"%<num_tasks%> clause");
+      *grainsize_seen = OMP_CLAUSE_CHAIN (*grainsize_seen);
+    }
+
   if (detach_seen)
     {
       if (mergeable_seen)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index df62e2d..f90c304 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -7098,6 +7098,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
   bool mergeable_seen = false;
   bool implicit_moved = false;
   bool target_in_reduction_seen = false;
+  bool num_tasks_seen = false;
 
   bitmap_obstack_initialize (NULL);
   bitmap_initialize (&generic_head, &bitmap_default_obstack);
@@ -7656,6 +7657,10 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  /* FALLTHRU */
 
 	case OMP_CLAUSE_NUM_TASKS:
+	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_NUM_TASKS)
+	    num_tasks_seen = true;
+	  /* FALLTHRU */
+
 	case OMP_CLAUSE_NUM_TEAMS:
 	case OMP_CLAUSE_NUM_THREADS:
 	case OMP_CLAUSE_NUM_GANGS:
@@ -9246,6 +9251,17 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	    }
 	  pc = &OMP_CLAUSE_CHAIN (c);
 	  continue;
+	case OMP_CLAUSE_GRAINSIZE:
+	  if (num_tasks_seen)
+	    {
+	      error_at (OMP_CLAUSE_LOCATION (c),
+			"%<grainsize%> clause must not be used together with "
+			"%<num_tasks%> clause");
+	      *pc = OMP_CLAUSE_CHAIN (c);
+	      continue;
+	    }
+	  pc = &OMP_CLAUSE_CHAIN (c);
+	  continue;
 	case OMP_CLAUSE_ORDERED:
 	  if (reduction_seen == -2)
 	    error_at (OMP_CLAUSE_LOCATION (c),
diff --git a/gcc/fortran/openmp.cc b/gcc/fortran/openmp.cc
index 315ec68..5246647 100644
--- a/gcc/fortran/openmp.cc
+++ b/gcc/fortran/openmp.cc
@@ -9175,6 +9175,13 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
     resolve_positive_int_expr (omp_clauses->grainsize, "GRAINSIZE");
   if (omp_clauses->num_tasks)
     resolve_positive_int_expr (omp_clauses->num_tasks, "NUM_TASKS");
+  if (omp_clauses->grainsize && omp_clauses->num_tasks)
+    gfc_error ("%<GRAINSIZE%> clause at %L must not be used together with "
+	       "%<NUM_TASKS%> clause", &omp_clauses->grainsize->where);
+  if (omp_clauses->lists[OMP_LIST_REDUCTION] && omp_clauses->nogroup)
+    gfc_error ("%<REDUCTION%> clause at %L must not be used together with "
+	       "%<NOGROUP%> clause",
+	       &omp_clauses->lists[OMP_LIST_REDUCTION]->where);
   if (omp_clauses->async)
     if (omp_clauses->async_expr)
       resolve_scalar_int_expr (omp_clauses->async_expr, "ASYNC");
diff --git a/gcc/testsuite/c-c++-common/gomp/clause-dups-1.c b/gcc/testsuite/c-c++-common/gomp/clause-dups-1.c
index a17f68d..6fc53e8 100644
--- a/gcc/testsuite/c-c++-common/gomp/clause-dups-1.c
+++ b/gcc/testsuite/c-c++-common/gomp/clause-dups-1.c
@@ -107,10 +107,10 @@ f1 (int *p)
   #pragma omp taskloop num_tasks (2) num_tasks (2)		/* { dg-error "too many 'num_tasks' clauses" } */
   for (i = 0; i < 8; ++i)
     f0 ();
-  #pragma omp taskloop num_tasks (1) grainsize (2)
+  #pragma omp taskloop num_tasks (1) grainsize (2)		/* { dg-error "'grainsize' clause must not be used together with 'num_tasks' clause" } */
   for (i = 0; i < 8; ++i)
     f0 ();
-  #pragma omp taskloop grainsize (2) num_tasks (2)
+  #pragma omp taskloop grainsize (2) num_tasks (2)		/* { dg-error "'grainsize' clause must not be used together with 'num_tasks' clause" } */
   for (i = 0; i < 8; ++i)
     f0 ();
   #pragma omp taskloop collapse (1) collapse (1)		/* { dg-error "too many 'collapse' clauses" } */
diff --git a/gcc/testsuite/gfortran.dg/gomp/pr115103.f90 b/gcc/testsuite/gfortran.dg/gomp/pr115103.f90
new file mode 100644
index 0000000..9fb4979
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/gomp/pr115103.f90
@@ -0,0 +1,14 @@
+subroutine nogroup_reduction
+  integer :: i, r
+  r = 0
+!$omp taskloop nogroup reduction(+:r) ! { dg-error "'REDUCTION' clause at .1. must not be used together with 'NOGROUP' clause" }
+  do i = 1, 32
+    r = r + i
+  end do
+end
+subroutine grainsize_num_tasks
+  integer :: i
+!$omp taskloop grainsize(2) num_tasks(2) ! { dg-error "'GRAINSIZE' clause at .1. must not be used together with 'NUM_TASKS' clause" }
+  do i = 1, 32
+  end do
+end