[llvm-branch-commits] [llvm] [RISCV] Add initial support of memcmp expansion (PR #107548)

[Pengcheng Wang via llvm-branch-commits]

wangpc-pp wrote:

> > > > The run just finished, I'm seeing a 0.75% improvement on 500.perlbench_r on the BPI F3 (-O3 -mcpu=spacemit-x60), no regressions or improvements on the other benchmarks as far as I can see. Seems to check out with the number of memcmps inlined reported for perlbench!
> > 
> > > 
> > 
> > > Does spacemit-x60 support unaligned scalar memory and was your test with or without that enabled?
> > 
> > 
> > 
> > It supports unaligned scalar but not unaligned vector. And it seems we don't add these features to `-mcpu=spacemit-x60`. So I think @lukel97 ran the SPEC without unaligned scalar.
> 
> Yeah, -mno-strict-align gave a bus error. I ultimately built it without unaligned scalar since I wasn't sure if unaligned scalar was performant or not. 

IIRC, we have separated this into two options(scalar/vector) now. So maybe we can specify the scalar one.

https://github.com/llvm/llvm-project/pull/107548