[llvm] [AMDPU] More support for SILoadStoreOptimizer of buffer instructions (PR #86285)

[David Stuttard via llvm-commits]

dstutt wrote:

> > Can't do the merging on buffer_load_format since the format isn't known at compile time.
> 
> But that's all this does?

It also adds buffer_load_dword*_idxen/bothen 


https://github.com/llvm/llvm-project/pull/86285