[flang] [compiler-rt] [clang] [llvm] [clang-tools-extra] [Flang][OpenMP] Restructure recursive lowering in `createBodyOfOp` (PR #77761)

[Kiran Chandramohan via cfe-commits]

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@@ -2186,11 +2178,43 @@ static void createBodyOfOp(
     const llvm::SmallVector<const Fortran::semantics::Symbol *> &args = {},
     bool outerCombined = false, DataSharingProcessor *dsp = nullptr) {
   fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
+
+  auto insertMarker = [](fir::FirOpBuilder &builder) {
+    mlir::Value undef = builder.create<fir::UndefOp>(builder.getUnknownLoc(),
+                                                     builder.getIndexType());
+    return undef.getDefiningOp();
+  };
+
+  // Find the block where the OMP terminator should go. In simple cases
+  // it is the single block in the operation's region. When the region
+  // is more complicated, especially with unstructured control flow, there
+  // may be multiple blocks, and some of them may have non-OMP terminators
+  // resulting from lowering of the code contained within the operation.
+  // By OpenMP rules, there should be a single exit point from the region:
+  // here exit means transfering control to the code following the operation.
+  // STOP statement is allowed and does not count as exit for the purpose of
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kiranchandramohan wrote:

Where is the STOP statement accounted for here? The code here looks like find the block without a terminator and assert that there is only ONE.

https://github.com/llvm/llvm-project/pull/77761