[llvm] [AMDGPU] Support divergent sized dynamic alloca (PR #121148)

[Pravin Jagtap via llvm-commits]

pravinjagtap wrote:

> > Currently, AMDGPU backend supports static sized allocas.
> > This patch extends support for truly dynamic sized allocas.
> 
> Update this description as well as the title.

The title is already updated by matt.

https://github.com/llvm/llvm-project/pull/121148