What should happen here?

[deadalnix]

On Sunday, 26 September 2021 at 20:39:48 UTC, Steven 
Schveighoffer wrote:
> You realize what `GC.addRoot` does? It adds a pointer to a 
> treap, through a virtual function call after taking a global 
> lock. Pushing a stack item is going to be at least 10x faster, 
> probably more compared to that. In the function call alone, 
> there are a few stack pushes.
>
> -Steve

Sure, but it does so exclusively for one specific address. The 
optimizer would have to do so for every single thing that might 
be pointing to something that is owned by the GC.

However, one thing that could be done is to have an intrinsic to 
do so, so the optimizer knows exactly which references not to 
mess with. LLVM already has intrinsics for this at the IR level.