[llvm] x86: fix musttail sibcall miscompilation (PR #168956)

[Folkert de Vries via llvm-commits]

https://github.com/folkertdev commented:

Bit of a procedural question: how should I handle rebasing and force pushes? For me switching branches between different PRs kind of trashes the cache (ccache helps, but it's still a couple of minutes). So, instead I rebase to whatever latest upstream I've pulled in, but then every push is a force push, and reviewing those is difficult (and sometimes buggy). 

Over in the rust repository we have a bot make nice range diffs e.g. since the last review, e.g. 

https://github.com/rust-lang/rust/pull/148302#issuecomment-3490607077

So, how does llvm deal with this in a way that is convenient for the author and the reviewer?

https://github.com/llvm/llvm-project/pull/168956