[llvm-commits] XOP Feature flag

[Jan Sjodin]

No it is not possible to have FMA4 wihtout XOP, and if a processor supports them AVX is also supported. I suppose it would be possible to combine the FMA4 and XOP flags to FMA4XOP or something.


- Jan





----- Original Message -----
> From: Bruno Cardoso Lopes <bruno.cardoso at gmail.com>
> To: Jan Sjodin <jan_sjodin at yahoo.com>
> Cc: "llvm-commits at cs.uiuc.edu" <llvm-commits at cs.uiuc.edu>
> Sent: Thursday, December 1, 2011 5:49 PM
> Subject: Re: [llvm-commits] XOP Feature flag
> 
> On Thu, Dec 1, 2011 at 8:17 PM, Jan Sjodin <jan_sjodin at yahoo.com> wrote:
>>  Patch to add XOP feature.
> 
>        if (IsAMD && ((ECX >> 16) & 0x1)) {
>          HasFMA4 = true;
>          ToggleFeature(X86::FeatureFMA4);
> +        HasXOP = true;
> +        ToggleFeature(X86::FeatureXOP);
> 
> Out of curiosity: is it possible to have a amd processor with FMA4 but
> without XOP or vice-versa?
> LGTM, please apply!
> 
> -- 
> Bruno Cardoso Lopes
> http://www.brunocardoso.cc
>