[i386] Replace builtins with vector extensions

[Ulrich Drepper]

On Sat, Jun 28, 2014 at 6:42 AM, Marc Glisse <marc.glisse@inria.fr> wrote:
> Ping,
>
> nobody has an opinion on this? Or some explanation why I am mistaken to
> believe that #pragma target makes it safer now?
>
> It would enable a number of optimizations, like constant propagation, FMA
> contraction, etc. It would also allow us to remove several builtins.

I see no problem with using the array-type access to the registers.

As for replacing the builtins with arithmetic operators: I appreciate
the possibility for optimization.  But is there any chance the calls
could not end up being implemented with a vector instruction?  I think
that would be bad.  The intrinsics should be a way to guarantee that
the programmer can create vector instructions.  Otherwise we might
just not support them.