[PATCH] D93838: [SCCP] Add Function Specialization pass

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

Let's discuss a way forward with this.

Data and analysis has shown that regarding increased compile-times:

- there there is not one single pass to blame (if that were the case, there could perhaps have been an easy fix);
- the obvious way to control this, is to specialise less, based on a cost-model that also takes function size into account, which looks fairly straightforward to plumb in to me as a first step,
- and compile-times is not a disaster at the moment! The overhead will be bigger perhaps with shorter compile times, and less visible with larger. Also, it currently is in line with GCC, which has this enabled by default.

I would like to propose this as an initial version so that we can get more experience with this, and also very importantly, others can contribute and help with this.

then, as a follow up my plan is now to:

- look at code-size grow and control it,
- and study and document GCC's cost-model.

Agreed @fhahn , @xbolva00 , @ChuanqiXu , @sanwou01 ?


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https://reviews.llvm.org/D93838