[llvm] [AMDGPU] Add SSA-form memory clause pass (SSASIFormMemoryClauses) (PR #209656)

[Christudasan Devadasan via llvm-commits]

cdevadas wrote:

> Also I would expect this to be called something like `SIFormSSAMemoryClauses` or `GCNFormSSAMemoryClauses`, i.e. maintaining an existing prefix with SSA somewhere later in the name.

`AMDGPUFormSSAMemoryClauses.cpp` would fit well. We shouldn't introduce any more SI* GCN* filenames. We must change the existing filenames at some point to use the AMDGPU prefix.

https://github.com/llvm/llvm-project/pull/209656