[clang] [llvm] [WIP] Correct lowering of `fp128` intrinsics (PR #76558)

[Trevor Gross via cfe-commits]

tgross35 wrote:

In either case, I need to have the module flags available pretty early and I'm not sure how to do that. Ideally they would be available when `TargetLowering` is constructed or sometime before it is used for lowering, but it only gets a `TargetMachine` as a paremeter. All values in `TargetOptions` seem to be configured once and don't pay attention to module flags or take the module as a parameter - is there a reason for that? I'm wondering if `TargetMachine` is intended to be unchanging across different modules.

https://github.com/llvm/llvm-project/pull/76558