[PATCH] Optimize insertqi when we copy all the lower 64 bits.

[Nadav Rotem]

On Apr 23, 2014, at 6:56 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote:

> On 15 April 2014 14:04, Nadav Rotem <nrotem at apple.com> wrote:
>> Hi Filipe,
>> 
>> Why is this an IR-level transform? Could you implement this in SelectionDAG ?
> 
> What is the advantage of doing this at SelectionDAG? Since this is an
> intrinsic, we know all that we need at the IR level already. IR also
> has the advantage of opening the potential for further optimizations

It is not clear to me why we represent this intrinsic as an IR-level intrinsic and not as a regular insertelement instruction. We already have IR-level optimizations on insertelement and I prefer not to duplicate all of them. 

> an has much better testing than SelecetionDAG.
> 
> Cheers,
> Rafael