[llvm] [LAA] Hoist setting condition for RT-checks (NFC) (PR #128045)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> I added one case where this changes behavior in [8bdcd0a](https://github.com/llvm/llvm-project/commit/8bdcd0a96e65557c8c3bf506d186c49002db6463)

Interesting, I seem to have misunderstood something.
 
> Not looked closely at it, but I think previously the code should only retry with runtime checks if there is an unknown dependence with non-constant distance.
> 
> Now we will always retry with runtime checks, even if we had a non-constant distance that isn't unknown?

My misunderstanding is the following: wouldn't ShouldRetryWithRuntimeChecks only be respected when the dependence is unknown? Why would we retry with runtime checks if the dependence is Forward, Backward etc?

https://github.com/llvm/llvm-project/pull/128045