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Re: combine permutations in gimple
On Wed, Aug 15, 2012 at 2:29 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Aug 15, 2012 at 02:15:03PM +0200, Richard Guenther wrote:
>> Ok. That would still leave us with the issue Ramana brought up - the
>> target hook returning true unconditionally if a generic permute is implemented.
>> We just avoid generic expansion by tree-vect-generic.c that way.
>
> Yeah, if there is a generic permute, can_vec_perm_p will return true always
> for the modes for which it is available. Which is why I've been suggesting
> also the target hook which should return false if only generic permute is
> going to be used.
Well. What about returning a cost instead? We don't want to transform
two insns to four either.
Richard.
> Jakub