nikic added a comment.

In D141899#4061237 <https://reviews.llvm.org/D141899#4061237>, @zixuan-wu wrote:

> With considering 
> https://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility I think 
> we need make consensus to choose one option from following 2 options.
>
> 1. Remove X86amx type in IR totally. (what I am doing now)
> 2. Without removing X86amx type in IR, just upgrade the x86amx type to target 
> extension and also upgrade bitcast llvm instruction to intrinsic(required). 
> It also includes changing the testcase to target extension type.

I believe the right option is:

3. Remove x86_amx type from the (in-memory) IR representation, but support an 
auto-upgrade for bitcode only.

We do need bitcode auto-upgrade support as a matter of policy, and we shouldn't 
support both type representation at the same time, that would defeat the point 
of the change.

In D141899#4061174 <https://reviews.llvm.org/D141899#4061174>, @LuoYuanke wrote:

> I think target extension type is nice, if it is introduced 2 years ago I 
> would vote for it. However my concern is the compatibility issue as I 
> explained. We need to be compatible to the IR that built by previous 
> compiler, and be compatible to the 3rd party software that based on the 
> x86_amx type. I can't predict more risks for now if we replace an LLVM IR 
> type, but I believe there is big risk hidden.

Due to bitcode auto-upgrade, compatibility with old IR is retained. As long as 
we avoid some of the API changes here, the impact on downstream code should be 
fairly minimal. (Though as already pointed out, downstream impact generally 
doesn't figure into LLVM design decisions anyway.)


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D141899/new/

https://reviews.llvm.org/D141899

_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits

Reply via email to