[llvm] [SLP] Make getSameOpcode support interchangeable instructions. (PR #133888)

[Reid Kleckner via llvm-commits]

rnk wrote:

> @aeubanks I have a new version already https://github.com/llvm/llvm-project/pull/135797.

OK, but can you confirm that the issue has been fixed? If you aren't confident that both issues have been fixed, it's our project policy to revert first and ask questions later:
https://llvm.org/docs/DeveloperPolicy.html#patch-reversion-policy
"As a community, we strongly value having the tip of tree in a good state while allowing rapid iterative development."

At EuroLLVM I spoke to multiple other individuals for whom the SLP vectorizer is the #1 source of toolchain instability. I have seen issues reported to SLP v developers with responses like along the lines of, this feedback is too late, we've already moved on, it will be hard to rollback. IMO these are not valid excuses for allowing tip-of-tree to be unstable. When a user reports a correctness issue in LLVM, as compiler developers, correctness is paramount, and we should take it seriously.

So, with that in mind, I would appreciate confirmation of whether the reported issue has been fixed.

https://github.com/llvm/llvm-project/pull/133888