[flang-commits] [flang] [flang][OpenMP] Map `teams loop` to `teams distribute` when required. (PR #127489)

[Sergio Afonso via flang-commits]

================
@@ -179,3 +180,86 @@ subroutine test_standalone_bind_parallel
     c(i) = a(i) * b(i)
   end do
 end subroutine
+
+! CHECK-LABEL: func.func @_QPteams_loop_cannot_be_parallel_for
+subroutine teams_loop_cannot_be_parallel_for
+  implicit none
+  integer :: iter, iter2, val(20)
+  val = 0
+  ! CHECK: omp.teams {
+
+  ! Verify the outer `loop` directive was mapped to only `distribute`.
+  ! CHECK-NOT: omp.parallel {{.*}}
+  ! CHECK:     omp.distribute {{.*}} {
+  ! CHECK-NOT:   omp.wsloop
+  ! CHECK:       omp.loop_nest {{.*}} {
+
+  ! Verify the inner `loop` directive was mapped to a worksharing loop.
+  ! CHECK:         omp.wsloop {{.*}} {
+  ! CHECK:           omp.loop_nest {{.*}} {
+  ! CHECK:           }
+  ! CHECK:         }
+
+  ! CHECK:       }
+  ! CHECK:     }
+
+  ! CHECK: }
+  !$omp target teams loop map(tofrom:val)
+  DO iter = 1, 5
+    !$omp loop bind(parallel)
+    DO iter2 = 1, 5
+      val(iter+iter2) = iter+iter2
+    END DO
+  END DO
+end subroutine
+
+subroutine foo()
+end subroutine
+
+! CHECK-LABEL: func.func @_QPteams_loop_cannot_be_parallel_for_2
+subroutine teams_loop_cannot_be_parallel_for_2
+  implicit none
+  integer :: iter, val(20)
+  val = 0
+
+  ! CHECK: omp.teams {
+
+  ! Verify the `loop` directive was mapped to only `distribute`.
+  ! CHECK-NOT: omp.parallel {{.*}}
+  ! CHECK:     omp.distribute {{.*}} {
+  ! CHECK-NOT:   omp.wsloop
+  ! CHECK:       omp.loop_nest {{.*}} {
----------------
skatrak wrote:

```suggestion
  ! CHECK-NEXT:       omp.loop_nest {{.*}} {
```

https://github.com/llvm/llvm-project/pull/127489