[clang] [llvm] [DirectX] Making sure SROA is run when targeting DirectX (PR #179600)

[Chris B via llvm-commits]

llvm-beanz wrote:

What is the driving reason for this change? I worry that doing this in isolation without a larger plan for how we're going preserve debug information is potentially a step in the wrong direction.

@bogner, would really like your thoughts here too.

https://github.com/llvm/llvm-project/pull/179600