[PATCH] D26191: [ARM] Patch to improve memcpy inlined assembly sequence.

[Ranjeet Singh via llvm-commits]

rs added a comment.

Thanks for your review  comments Eli.

> The IR is definitely the right place to do this... trying to do the sort of modifications required for this any later would be messy at best.
> This needs to be generalized beyond handling just i8 arrays; this would probably trigger with some frequency on structs with small members.

Do you have any suggestions where this modification can be plugged in ? Or do you think it's fine as a pass but needs to be generalised ?

> This is probably interesting for other targets to some extent; other common architectures don't have LDM/STM, but they have larger registers which could benefit from a similar transformation (for example, on x86, SSE registers are used to lower memcpy.)

ok

> Granted, I'm also skeptical that this actually triggers frequently enough to be worth bothering; saying it only triggers a few times in the entirety of LNT isn't exactly encouraging.

After generalising it a bit more it might be able to optimise more examples in LNT.


https://reviews.llvm.org/D26191