On Wed, May 11, 2016 at 10:40:11AM +0200, Bernd Schmidt wrote: > On 05/11/2016 09:42 AM, Dominik Vogt wrote: > >On Tue, May 10, 2016 at 05:05:06PM +0200, Bernd Schmidt wrote: > >>Earlier in the discussion you mentioned the intention to remove > >>these costs. Nothing else in the function does cost calculations - > >>maybe you can try placing a gcc_unreachable into the case where the > >>costs would prevent the transformation to see if it ever triggers. > > > >You mean to try it out locally or as part of the patch? > > I meant try it out locally. I'm almost certain the patch shouldn't > be trying to use costs here.
That's what I mentioned somewhere during the discussion. The s390 backend just uses COSTS_N_INSNS(1) for AND as well as ZERO_EXTEND, so this won't ever trigger. I just left the rtx_cost call in the patch for further discussion as Jeff said he liked the approach. We don't need it to achieve the behaviour we want for s390. Ciao Dominik ^_^ ^_^ -- Dominik Vogt IBM Germany