Why not mark everything inline?

Question

First off, I am not looking for a way to force the compiler to inline the implementation of every function.

To reduce the level of misguided answers make s

Answer 1

That's pretty much the philosophy behind Whole Program Optimization and Link Time Code Generation (LTCG) : optimization opportunities are best with global knowledge.

From a practical point of view it's sort of a pain because now every single change you make will require a recompilation of your entire source tree. Generally speaking you need an optimized build less frequently than you need to make arbitrary changes.

I tried this in the Metrowerks era (it's pretty easy to setup with a "Unity" style build) and the compilation never finished. I mention it only to point out that it's a workflow setup that's likely to tax the toolchain in ways they weren't anticipating.