[llvm] [LAA][NFC] Add a test for #191867 (PR #213722)

[Ramkumar Ramachandra via llvm-commits]

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@@ -348,6 +348,106 @@ exit:
   ret void
 }
 
+; Same as above but with an unrelated store-to-load forwarding deps that do have
+; a safe VF. Make sure those aren't reported as ;
+; `BackwardVectorizableButPreventsForwarding`. We provide two of those (%B and
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artagnon wrote:

Wrapping issue?

https://github.com/llvm/llvm-project/pull/213722