[flang-commits] [flang] [Flang][OpenMP] Add Semantics support for Nested OpenMPLoopConstructs (PR #145917)

[Tom Eccles via flang-commits]

================
@@ -761,10 +761,13 @@ void OmpStructureChecker::Enter(const parser::OpenMPLoopConstruct &x) {
   }
   SetLoopInfo(x);
 
-  if (const auto &doConstruct{
-          std::get<std::optional<parser::DoConstruct>>(x.t)}) {
-    const auto &doBlock{std::get<parser::Block>(doConstruct->t)};
-    CheckNoBranching(doBlock, beginDir.v, beginDir.source);
+  auto &optLoopCons = std::get<1>(x.t);
+  if (optLoopCons.has_value()) {
+    if (const auto &doConstruct{
+            std::get_if<parser::DoConstruct>(&*optLoopCons)}) {
+      const auto &doBlock{std::get<parser::Block>(doConstruct->t)};
+      CheckNoBranching(doBlock, beginDir.v, beginDir.source);
+    }
----------------
tblah wrote:

Please could you also add a check which dissalows nests where the loop is in the middle e.g.

```
!$omp parallel do
do ...
!$omp unroll
```

https://github.com/llvm/llvm-project/pull/145917