[PATCH] D140210: [IPSCCP] Enable specialization of functions.

Fri Dec 16 09:44:41 PST 2022

fhahn added a comment.

In D140210#4001715 <https://reviews.llvm.org/D140210#4001715>, @labrinea wrote:

> In D140210#4001467 <https://reviews.llvm.org/D140210#4001467>, @nikic wrote:
>
>> Some more detailed compile-time data: https://llvm-compile-time-tracker.com/compare.php?from=e6676a1382ff4c8f6c520486323430745948481d&to=8d528eb8ebe0261d187fef57829f1db20f42752c&stat=instructions%3Au
>>
>> I notice that there is a 50% increase in code size on terminator.c from SPASS. Did this large change get analyzed at some point?
>
> This particular regression has not been examined, but codesize has been discussed here https://reviews.llvm.org/D139346?vs=on&id=481234#toc
> **llvm/lib/Transforms/IPO/FunctionSpecialization.cpp:300**
>
>> TODO: Currently "budget" is derived from max number of specializations per function. A more reasonable metric would be acceptable increase in code size.
>
> Right now we are keeping up to `NumCandidates x (MaxClonesThreshold=3)` which could be too large for small modules.

Should we estimate the size of the module and limit the total size increase?

Repository:
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  https://reviews.llvm.org/D140210/new/

https://reviews.llvm.org/D140210