[PATCH] D96462: [LV] Add remarks that explicitly mention error handling in candidate loops

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

Thanks for working on improving the remarks! Unfortunately we have to be careful to keep them generic with respect to the frontend. I don't think we should be  using a function name string to detect using `assert` and include other implementation specific parts (like `NDEBUG`) in the message. For example, the user could define their own `__assert_fail` function or the IR could be coming from a Rust or Swift frontend.



================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp:1078
+            "loop control flow is not understood by vectorizer. "
+            "Loop contains control flow that does not return",
+            "CFGNotUnderstood", ORE, TheLoop, U);
----------------
In this case, the loop *technically* does not contain the `unreachable`, right? One of the exit blocks does. I am not sure how to best phrase it, but it might be worth adjusting the message below `reportVectorizationFailure("The loop must have a unique exit block",` to include the information that some of the exit blocks end in `unreachable`

Unfortunately I don't think the user can do much with this information.


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