[LLVMdev] Problems with optimizations and va_arg intrinsic

[Rinaldini Julien]

Hi !

Thanks for your answer… I’ll look at how clang implement the va_arg instruction in IR to see how it works !

Cheers


Le 20 déc. 2013 à 08:59, Tim Northover <t.p.northover at gmail.com> a écrit :

> Hi Rinaldini,
> 
>> I know that clang is *not* relying on the va_arg intrinsic, but implements itself this set of function, hence my question: is the va_arg intrinsic
>> something we can trust to work with, or not?
> 
> Probably not, Someone seems to have made an attempt to get something
> working in the x86 backend, but unfortunately it doesn't have all the
> information needed to obey the ABI properly (e.g. for over-aligned
> struct types, LLVM just doesn't know that the type itself is
> over-aligned). I certainly wouldn't want to rely on it.
> 
> Cheers.
> 
> Tim.