[llvm] [FunctionAttrs] deduce attr `cold` on functions if all CG paths call a `cold` function (PR #101298)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

I'm not sure that smaller but more functions necessarily means more compile time, larger functions tend to exasperate superlinear compile times.

Can you post a llvm-compile-time-tracker link (even though it won't necessarily show the second order effects since you tend to need FDO profiles for mark functions as cold)?

https://github.com/llvm/llvm-project/pull/101298