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

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > I don't think it actually does take that into account. I see it used in x86 and Mip's TargetMachine constructors, but I don't see this wired up to TFL.
> 
> ~TFL~ Subtarget is constructed with the value of the flag here
> 

I think this is a bug. I don't believe anything in TargetMachine should depend on context IR. You can recycle the TargetMachine for different compilations. The TargetMachine owns the subtarget map, which is keyed off the target-cpu/target-features, and could be used from different modules with different flags.

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