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

[Eli Friedman via llvm-commits]

efriedma added a comment.

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.

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.)

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.


https://reviews.llvm.org/D26191