[llvm] [CodeGen] Get stack alignment from TargetFrameLowering (NFCI) (PR #105477)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> DL.getStackAlignment() because the DataLayout method asserts if the stack alignment wasn't specified.

This is just a bug that should be fixed? 

https://github.com/llvm/llvm-project/pull/105477