[llvm-dev] TBAA falsely reporting may alias?

[Daniel Berlin via llvm-dev]

On Mon, Apr 17, 2017, 3:08 AM Kavon Farvardin <kavon at farvard.in> wrote:

> By "dropped" do you mean that the metadata is not propagated/preserved
> during the transformation?
>

Yes

>
> If anyone knows which passes in particular are doing this, I would be
> happy to try to come up with a patch!
>

+Ben

>
> ~kavon
>
> On Apr 14, 2017, at 3:52 PM, Daniel Berlin <dberlin at dberlin.org> wrote:
>
>
>
> On Fri, Apr 14, 2017 at 6:12 AM, Hal Finkel via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>>
>> On 04/14/2017 08:03 AM, Kavon Farvardin via llvm-dev wrote:
>>
>>> Thanks for the explanation Sanjoy!
>>>
>>> Another question I have is: are there are any passes that invalidate or
>>> make the TBAA analysis information less precise?
>>>
>>
>> Some transformation drop TBAA information when they might invalidate it,
>> but it should be preserved in most places.
>>
>>
> FWIW, I believe some folks at Google in a different group have come to the
> conclusion it is dropped in about 20-30% of cases.
> (I said "file bugs")
>
>
>
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