[compiler-rt] [AArch64][compiler-rt] Add memcpy, memset, memmove, memchr builtins. (PR #77496)

[David Green via llvm-commits]

davemgreen wrote:

I had forgotten that vectorization was disabled in streaming functions. That would make sense why we don't see SVE instructions so far. It sounds like there is plenty of work yet to go.

Hopefully there will be a lot of overlap with mops instructions, which would help simplify things a lot.

https://github.com/llvm/llvm-project/pull/77496