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.
Jakub
