[PATCH] GlobalOpt: Apply fastcc to internal x86_thiscallcc functions

[Rafael Espíndola]

> I don't think we should give an explicit list based on what GlobalOpt does
> today, because it will change.
>
> Ultimately, if users want to preserve the calling convention of internal
> functions, they should use llvm.used / compiler_used.  I just don't want to
> break them right now.
>
> If we update LangRef, I would say that optimizers are allowed to change
> calling conventions of functions if it can simultaneously update all
> possible callers.  But, even that feels too specific. It's generally implied
> that LLVM's optimizers can do anything that the user can't observer, and
> this feels pretty close to that.

Fair enough. We really have to find time to figure out something
better than llvm.used.

Cheers,
Rafael