[clang] [OpenMP] Fix crash with extern reference and diagnose loop variable reuse in collapsed loops. (PR #203252)

[Alexey Bataev via cfe-commits]

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@@ -0,0 +1,107 @@
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=51 %s
+// RUN: %clang_cc1 -verify -fopenmp-simd -fopenmp-version=51 %s
+
+// This test verify two behaviors:
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alexey-bataev wrote:

```suggestion
// This test verifies two behaviors:
```

https://github.com/llvm/llvm-project/pull/203252