[flang-commits] [flang] [flang] Lowering fortran structured do-while loops to `scf.while` (PR #177476)

[via flang-commits]

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@@ -1644,6 +1650,111 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     genConditionalBranch(cond, trueTarget->block, falseTarget->block);
   }
 
+  bool doWhileHasEarlyExit(const Fortran::lower::pft::Evaluation &outerDoWhile,
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jeanPerier wrote:

I think the PFT logic should be changed instead so that it does not flag all DO WHILE as unstructuredContext.

The PFT is in charge of looking for early exits.

So I think that if you add your switch to control the setting of `eval.isUnstructured` [here ](https://github.com/llvm/llvm-project/blob/e85bbd09491f3409cf4d844e6f57e91ab028defa/flang/lib/Lower/PFTBuilder.cpp#L1063), you can then remove `doWhileHasEarlyExit` and use `unstructuredContext` in Bridge.cpp to control the generation of scf vs cf. 

https://github.com/llvm/llvm-project/pull/177476