[LLVMdev] [Proposal] Parallelize post-IPO stage.

[Shuxin Yang]

On 7/14/13 5:57 PM, Andrew Trick wrote:
>
> On Jul 12, 2013, at 3:49 PM, Shuxin Yang <shuxin.llvm at gmail.com 
> <mailto:shuxin.llvm at gmail.com>> wrote:
>
>> 6) Miscellaneous
>> ===========
>>   Will partitioning degrade performance in theory.  I think it 
>> depends on the definition of
>> performance.  If performance means execution-time, I guess it dose not.
>> However, if performance includes code-size, I think it may have some 
>> negative impact.
>> Following is few scenario:
>>
>>   - constants generated by the post-IPO passes are not shared across 
>> partitions
>>   - dead func may be detected during the post-IPO stage, and they may 
>> not be deleted.
>
> In don't know if it's feasible, but stable linker output, independent 
> of the partioning, is highly desirable.
In theory, it is not possible. But I guess in practice, it is almost 
stable.

> One of the most irritating performance regressions to track down 
> involves different versions of the host linker. If partitioning 
> decisions are thrown into the mix, this could be annoying. Is it 
> possible for the final link to do a better job cleaning up?
>
>
If partition's tweaking parameter remain unchanged,  the partition 
should remain unchanged as well.

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