[llvm] r308078 - [ThinLTO] Ensure we always select the same function copy to import

[Chandler Carruth via llvm-commits]

On Sat, Jul 15, 2017 at 9:39 AM Chandler Carruth <chandlerc at gmail.com>
wrote:

> On Sat, Jul 15, 2017 at 12:53 AM Teresa Johnson via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: tejohnson
>> Date: Fri Jul 14 21:53:05 2017
>> New Revision: 308078
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=308078&view=rev
>> Log:
>> [ThinLTO] Ensure we always select the same function copy to import
>>
>> Summary:
>> Check if the first eligible callee is under the instruction threshold.
>> Checking this on the first eligible callee ensures that we don't end
>> up selecting different callees to import when we invoke this routine
>> with different thresholds due to reaching the callee via paths that
>> are shallower or hotter (when there are multiple copies, i.e. with
>> weak or linkonce linkage). We don't want to leave the decision of which
>> copy to import up to the backend.
>>
>> Reviewers: mehdi_amini
>>
>> Subscribers: inglorion, fhahn, llvm-commits
>>
>> Differential Revision: https://reviews.llvm.org/D35436
>>
>> Added:
>>
>> llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport_resolved1.ll
>>
>> llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport_resolved2.ll
>>     llvm/trunk/test/Transforms/FunctionImport/funcimport_resolved.ll
>>
>
> This newly added test appears to be flaky, showing some nondeterminism in
> the system. For example, this command will run the tests 100 times, and
> doing this I see roughly 5 failures:
>
> % repeat 100 ./dev/bin/llvm-lit -s ../test/Transforms/FunctionImport
>
> The build bots have been failing and then recovering because of this for
> some time, so I'm going to revert until we can get this fixed to lessen the
> build bot spam.
>

Reverted in r308095, let me know if i can help tracking it down.
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