Re: [PATCH tip] x86/percpu: Rewrite arch_raw_cpu_ptr()

[Linus Torvalds]

On Fri, 13 Oct 2023 at 12:30, Uros Bizjak <ubizjak@xxxxxxxxx> wrote:
>
> There are some other issues when memory access to the percpu area is
> implemented with an asm. An ongoing analysis shows that compilers
> can't CSE asm over basic-block boundaries, the CSE of asm is a very
> simple pattern matching through the BB.

Ahh. That explains the odd "partial CSE".

I was assuming that CSE was done on the SSA level with some dominance
analysis. Which presumably all the load simplification ends up doing.

              Linus