[clang] [llvm] [SPIRV] add pre legalization instruction combine (PR #122839)

[Vyacheslav Levytskyy via llvm-commits]

VyacheslavLevytskyy wrote:

> I rebased and the tests are passing locally. but they are still failing in ci.

It's the strange part. The thing is when I created a new https://github.com/llvm/llvm-project/pull/123191 today, I see all tests passing in CI before I press Merged. That's why I thought that we can see the same here after rebase. This https://github.com/llvm/llvm-project/pull/123191 today was created basing on fresh main. So, it's a bit weird.

https://github.com/llvm/llvm-project/pull/122839