[PATCH] D93078: [utils] Fix UpdateTestChecks case where 2 runs differ for last label

[Johannes Doerfert via Phabricator via cfe-commits]

jdoerfert added a comment.

In D93078#2499996 <https://reviews.llvm.org/D93078#2499996>, @mtrofin wrote:

> In D93078#2499995 <https://reviews.llvm.org/D93078#2499995>, @jdoerfert wrote:
>
>> In D93078#2499982 <https://reviews.llvm.org/D93078#2499982>, @mtrofin wrote:
>>
>>> In D93078#2499666 <https://reviews.llvm.org/D93078#2499666>, @jdoerfert wrote:
>>>
>>>> I think this caused a lot of problems for the Attributor tests. I get the "conflict output" warning all the time now :(
>>>>
>>>> These two `UpdateTestChecks` tests also generate the warning. I would think that they haven't before.
>>>>
>>>>   LLVM :: tools/UpdateTestChecks/update_test_checks/check_attrs.test
>>>>   LLVM :: tools/UpdateTestChecks/update_test_checks/prefix-never-matches.test
>>>>
>>>> I suspect the `--check-attributes` flag effect are not taken into account somewhere but I might be wrong.
>>>
>>> The warnings are correct, but their purpose is to inform. For example, take check_attrs. The third and fourth opt run produce different function attributes from those produced by the first two, so the function is different insofar as update_test_prefix is concerned. The warnings are there to indicate that the listed prefixes end up not being used. But, that's 'by design' for the attributor tests, IIRC.
>>>
>>> If the warnings are noise for you, we could add a flag to quiet them down, which you'd flip when regenerating attributor tests?
>>
>> TBH, before, the warnings meant there is a problem that needs fixing. Now they mean, there might be one or not. So, depending on your setup it's just noise while it was pure signal before.
>> I'm not sure how this is more helpful. What is the use case where this way of warning helps?
>
> For tests other than attributor, that explicitly set FileCheck --allow-unused-prefixes=true, these warnings mean that there will be unused prefixes (those listed)

Should not we check for that flag in the RUN line then and only warn for unused prefixes when it is set. If there is no prefix we should obviously always warn.


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https://reviews.llvm.org/D93078