[PATCH] D126984: [clang] Add support for optimize function attribute

Tue Jun 14 08:09:50 PDT 2022

xbolva00 added a comment.

In D126984#3581708 <https://reviews.llvm.org/D126984#3581708>, @aaron.ballman wrote:

> In D126984#3579842 <https://reviews.llvm.org/D126984#3579842>, @jdoerfert wrote:
>
>> In D126984#3571573 <https://reviews.llvm.org/D126984#3571573>, @aeubanks wrote:
>>
>>> IIRC in the past there was a strong preference to not have the pass manager support this sort of thing
>>> if you want to support this, there should be an RFC for how the optimization part of this will work as it may require invasive changes to the LLVM pass manager
>>>
>>> (if this is purely a clang frontend thing then ignore me)
>>
>> We actually should *not* make this a clang frontend only thing. It is confusing and not helpful. That said, we have code to integrate this into the new PM already as we were planning on proposing something along these lines too. We didn't manage to get to it during last years GSoC but the code could be used as a basis still.
>>
>> +1 for RFC
>> strong preference for proper integration of this into the new PM.
>
> I'm not opposed to an RFC to extend this functionality, but it seems to me that we have incremental progress already with this patch and landing this patch unblocks the work @steplong was originally doing for the MSVC pragma. Do you have a concern if we move forward with this less-functional form so that work isn't held up on an RFC for the more fully functional form?

I was thinking about this again and I am more and more unsure about this feature. -Os/-Oz is something more than just some attribute.

Look here: https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp and see lines (conditions) with SizeLevel and OptLevel.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126984/new/

https://reviews.llvm.org/D126984