[llvm] [SandboxIR] Delete SandboxIR/SandboxVectorizer (PR #166417)

[via llvm-commits]

vporpo wrote:

Hi Aiden,

It is true that the main authors and maintainers of this project no longer work at Google, and that activity has slowed down since about a year ago when I stopped working on it full time. But as you probably already know, this doesn't mean that the project is not being worked on, or maintained.
- Sandbox IR is in a stable state, which is why there hasn't been much need for activity, it just works.
- On the Sandbox Vectorizer side, things are still under development, but also in a stable state, with several feature patches in the pipeline. The last one is only a couple months old: https://github.com/llvm/llvm-project/pull/155079 which adds support of vectorizing arguments of different types, a feature missing from other vectorizers, and a feature that Google cared about.

> so that upstream does not have to bear the maintenance cost.

Both Sandbox IR and the Sandbox Vectorizer are self-contained. The only changes that would need maintenance are the ones that modify the core IR. I can see just one such change, the addition of the ptrtoaddr instruction in LLVM IR: 3a4b351ba18492b990b10fe5401c3bbaabcf2f94. Such changes are quite rare and usually need just a few straightforward changes in Sandbox IR.
What other maintenance cases do you have in mind?



https://github.com/llvm/llvm-project/pull/166417