[llvm] [AMDGPU][ASAN] Handle special GVs lowering in amdgpu-sw-lower-lds (PR #161827)

[Sameer Sahasrabuddhe via llvm-commits]

ssahasra wrote:

> On platform without hardware support, we can emulate named-barrier using LDS atomics.

Why? What's the software need to do that on older hardware?

https://github.com/llvm/llvm-project/pull/161827