[llvm-dev] llvm outlining question

[Minghwa Wang via llvm-dev]

Hi Ayal,

Do you have any CodeExtractor fixes I can use?

Thanks,
Ming-Hwa


On Tue, Apr 12, 2016 at 2:44 PM, Michael Kuperstein <
michael.kuperstein at gmail.com> wrote:

> I'm not aware of anything else in LLVM that performs outlining.
> Ayal (CCed) may be able to help you regarding CodeExtractor fixes.
>
> Thanks,
>   Michael
>
> On 12 April 2016 at 14:21, Minghwa Wang <mwang2 at cse.scu.edu> wrote:
>
>> Thank you Michael and Tom for the quick reply.
>>
>> According to your experience and comments, CodeExtractor is buggy only
>> works for special cases but not general enough for most usages. Then do we
>> have other outlining solution in llvm? Or I have to repeat what Michel done
>> before?
>>
>> Best regards,
>> Ming-Hwa
>>
>> On Tue, Apr 12, 2016 at 1:48 PM, Michael Kuperstein <
>> michael.kuperstein at gmail.com> wrote:
>>
>>> CodeExtractor sort of does this.
>>>
>>> First, it's a utility, not a pass - you'd still need to wrap it up with
>>> pass that actually causes it to outlines what you want it to outline.
>>>
>>> Second, it's a bit buggy. There are, as far as I know, two in-tree users
>>> of this utility: bugpoint, and partial inlining. Both of them are fairly
>>> specialized use-cases, and don't actually exercise the full generality of
>>> outlining an arbitrary region. And since a lot of cases are in practice
>>> untested - they don't quite work.
>>> I've had some fixes for this internally, but never actually upstreamed
>>> them, and no longer have access to that codebase. So, you'll probably run
>>> into the same issues if you try to do anything untrivial with it.
>>>
>>> Michael
>>>
>>>
>>>
>>> On 12 April 2016 at 13:24, Tom Chen via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Does this do what you want
>>>> http://llvm.org/docs/doxygen/html/classllvm_1_1CodeExtractor.html?
>>>>
>>>> 2016-04-12 14:58 GMT-05:00 Minghwa Wang via llvm-dev <
>>>> llvm-dev at lists.llvm.org>:
>>>>
>>>>> Is there any support for outlining in llvm?
>>>>>
>>>>> As we know outlining is the opposite of inlining and while
>>>>> refactoring, if we can outlining common code into functions, then function
>>>>> merge (supported by llvm) can be more efficient in reducing code size.
>>>>>
>>>>> If llvm support outlining, how to use it? Any documentation for it?
>>>>>
>>>>> Thanks,
>>>>> Ming-Hwa
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>>>
>>>>
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>>>>
>>>
>>
>
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