Re: PATCH: 0/6 [2nd try]: Add AVX support

H.J. Lu
2010-03-07T21:17:53Z

On Sun, Mar 7, 2010 at 1:07 PM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> On Sun, Mar 07, 2010 at 08:46:34PM +0100, Mark Kettenis wrote:
>> > From: Nathan Froyd <froydnj@codesourcery.com>
>> > The third alternative--again, what's adopted for the PPC SPE 64-bit
>> > registers--is to give %ymmNh their own DWARF register numbers.  I
>> > suppose it's also ABI-incompatible, but it seems like it fits with your
>> > approach much better than either of the above alternatives.
>>
>> I don't think that would be a good idea.  It means you can't refer to
>> something stored in a %ymmN register with a single register number.
>
> Sure you can.  GDB knows to merge %ymmNh with %xmmN if it needs to to
> make %ymmN, which will have only one register number.
>

We aren't going to give %ymmNh their own DWARF register numbers
in gcc 4.4. Mark's idea of using %ymmN register number for %xmmN
if AVX is available seems to work fine.

--
H.J.