[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 seem odd.

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