[llvm-branch-commits] [llvm] [AArch64] Disable SVE paired ld1/st1 for callee-saves. (PR #107406)

[Sander de Smalen via llvm-branch-commits]

sdesmalen-arm wrote:

> Hi, since we are wrapping up LLVM 19.1.0 we are very strict with the fixes we pick at this point. Can you please respond to the following questions to help me understand if this has to be included in the final release or not.

Sure, I appreciate your diligence!

> Is this PR a fix for a regression or a critical issue?

A critical issue.

> What is the risk of accepting this into the release branch?

There shouldn't be any risk of accepting this patch into the release branch. With this patch, the code reverts back to the behaviour that we've had for AArch64's SVE/SVE2 extensions which has been deployed for a 5+ years. This was basically a feature that went in and broke things, and this patch reverts that feature.

> What is the risk of NOT accepting this into the release branch?

Without this change, practically any code that targets AArch64's SME2 or SVE2p1 extensions will be broken.

https://github.com/llvm/llvm-project/pull/107406