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Re: [PATCH] Change vcond<mode> to vcond<mode1><mode2>
On Tue, Aug 30, 2011 at 11:07 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Tue, Aug 30, 2011 at 11:02:02AM +0200, Uros Bizjak wrote:
>> > Hmm. ?But then I'd have to try emit an insn, right? ?Currently
>> > the vectorizer simply looks for an optab handler ... the
>> > operands are not readily available (but their mode is known).
>> > So I'd create some fake regs, setup operands and call GEN_FCN
>> > on it? ?If it succeds I'd have to delete emitted insns, etc.
>> > Or I could add a target hook ...
>>
>> Hm... indeed, too much complication...
>>
>> I'd say, let's go with modeless operands and a target hook. IMO, this
>> is much more flexible than checking optab for supported modes.
>> Existing way is appropriate for single mode patterns, but we have
>> interdependent modes here, at least on x86.
>>
>> The hook would have two input arguments, insn mode and compare mode,
>> where the hook returns suggested supported compare mode, or no mode,
>> if it really can't handle requested modes.
>
> I think a two mode vcond pattern is in fact much cleaner than
> a one mode + modeless pattern which gen* will complain about and
> a target hook.
OK, but in this case, do not use mode iterators too much in order to
avoid invalid patterns.
Uros.