[llvm-dev] Need help reproducing a bug

[Steven Wu via llvm-dev]

> On Apr 18, 2018, at 9:11 AM, Roman Lebedev via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> On Wed, Apr 18, 2018 at 5:45 PM, Michael Zolotukhin via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>> Hi,
>> 
>> Recently I committed a change (r330175) that passed all my testing, but
>> failed on several bots. Namely, these are the failed ones:
>> http://lab.llvm.org:8011/builders/clang-with-thin-lto-ubuntu/builds/9803
>> http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/8173
>> http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/18082
> Note what *specifically* failed:
> * compare-compilers compare stage3 and stage4 compilers failed ( 0 secs )
> * compare-tablegen-inc-files compare stage3 and stage4 Tablegen inc
> files failed ( 1 secs )
> 
> I.e. it wasn't tests that failed.

Failing that tests means the compiler doesn't produce deterministic output because the stage3 and stage 4 compiler has to be the same.

Not sure about LLD test.

Steven

> 
>> I reverted the change (r330180), but now I’m stuck with how to proceed with
>> it, as I can’t reproduce any of these.
>> 
>> So far I’ve tried building clang with asan and using this sanitized clang to
>> build clang and lld one more time and run make check - none of these failed
>> on my machine. What else could I try to catch the issue?
>> 
>> In case you are interested in details and/or want to try to reproduce it,
>> you’ll need to revert r330180 (and thus reapply r330175). The change is
>> about using a new faster SSAUpdater in Jump Threading, more details are
>> available in the phabricator: https://reviews.llvm.org/D44282.
>> 
>> Thanks,
>> Michael
>> 
>> 
>> 
>> 
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>> llvm-dev at lists.llvm.org
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>> 
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