[PATCH] GlobalOpt: Apply fastcc to internal x86_thiscallcc functions

[Rafael Espíndola]

> What about things like the WebKit JS CC?  I assume the reason they do it
> that way is so that they can get GC roots in memory on the stack, and
> changing something like this to fastcc would break their GC.  The same might
> apply to the GHC convention, although I doubt it.  Changing the CC feels a
> lot like eliminating frame pointers, in that could mess with unwinders.
>
> I agree that LLVM IR semantics *allow* us to do this, but I didn't feel the
> need to rock this particular boat.

We should at least make that explicit in the language reference. In
the long run llvm.used and llvm.compiler_used should just be part of
the linkage, making them easier to use. We could then, for example,
require in the verifier that the WebKit JS CC is only used in
functions with a linkage that imply an invisible external use.

> If you just want to flip the naming around here to something like
> isProfitableToMakeFastCC() then that works for me.

Cheers,
Rafael