[llvm] [AMDGPU] Allow shinking instruction with dead sdst (PR #68028)

[Jay Foad via llvm-commits]

jayfoad wrote:

> > Oh, have you noticed that apart from `ds-combine-large-stride.ll`, every codegen diff is in a globalisel test, or a test with a globalisel RUN line? That seems odd.
> 
> That does not seem odd to me. These are the tests using auto-gen tests. I do not like these tests exactly for this reason.

You do not like these tests because they show the effect of your patch?

Then can you please include a `.ll` test that shows the effect of your patch on selectiondag codegen?

https://github.com/llvm/llvm-project/pull/68028