[cfe-dev] Removal of built-ins

[C Bergström via cfe-dev]

On Wed, Jun 1, 2016 at 11:26 PM, Reid Kleckner <rnk at google.com> wrote:
> Clang has never exposed the same set of builtins as GCC, though:
> http://clang.llvm.org/compatibility.html#vector_builtins
>
> I don't think we need to keep our IA32 vector builtin interface stable when
> the *mmintrin.h headers already provide a stable, portable, cross-vendor
> interface to the same functionality.

I didn't mention gcc.. I agree they shouldn't be used in the wild, but
they are..

Why not leave the built-in support and under the hood just map that to
something more portable? This is a pretty low cost (zero?) maintenance
burden...

Intentionally breaking stuff without at least giving any warning or
marking as deprecated in a major release 1st.. Is this an exception
because __built-ins are grey area support?