[llvm-dev] OptBisect implementation for new pass manager
David Greene via llvm-dev
llvm-dev at lists.llvm.org
Wed Sep 26 12:04:16 PDT 2018
But they're deeply connected. I debug codegen problems all the time.
That opt-bisect doesn't work with codegen is really unfortunate.
If opt-bisect should work with codegen then we need to think about how
codegen will work with the new PM.
I agree that whether or not the new PM becomes default is somewhat
orthogonal but eventually it will and at that point I hope we have a
functioning opt-bisect for codegen.
-David
Fedor Sergeev <fedor.sergeev at azul.com> writes:
> I would really like to separate OptBisect and New-PM-by-default
> discussions! :)
>
> regards,
> Fedor.
>
> On 09/26/2018 09:13 PM, David Greene wrote:
>> I'm concerned about codegen. If Codegen is not yet ready for the new
>> PM, should the new PM really become default? I would at least like to
>> see a plan of how Codegen is going to migrate before the new PM becomes
>> default. Codegen pass pipelines have been wonky ever since I started
>> working with LLVM and it would be nice to get that cleaned up.
>>
>> -David
>>
>> Philip Pfaffe <philip.pfaffe at gmail.com> writes:
>>
>>> Well, I think we don't have a clear idea about new-PM codegen should
>>> work in general. Is this really something that concerns us right now?
>>>
>>> Philip
>>>
>>> On Wed, Sep 26, 2018 at 7:54 PM Friedman, Eli
>>> <efriedma at codeaurora.org> wrote:
>>>
>>> On 9/26/2018 10:47 AM, Philip Pfaffe via llvm-dev wrote:
>>> > Hi Fedor,
>>> >
>>> > can you make an example where a pass actually needs to opt-out?
>>> > Because IMO, bisect should quite literally to DebugCounter-style
>>> skip
>>> > every step in every ::run method's loop. Passes should not even
>>> be
>>> > concerned with this.
>>> This isn't so much an issue for the optimization
>>> pipeline, but
>>> code
>>> generation involves some passes which are mandatory (e.g. isel).
>>> -Eli
>>> --
>>> Employee of Qualcomm Innovation Center, Inc.
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>>> a Linux Foundation Collaborative Project
>>>
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