On Mon, May 1, 2017 at 12:09 PM, Samuel Pitoiset <samuel.pitoi...@gmail.com> wrote: > On 05/01/2017 05:59 PM, Ilia Mirkin wrote: >> >> I think this is off. It shouldn't matter what the code sequence is, >> it's all representable. You need to teach replaceZero to not mess >> things up for SHLADD's src(1). > > > It's representable but stupid to do it. We should keep the ADD there and > this also avoids a workaround in the replaceZero logic just for that. > > IMHO, this is the better solution.
Yes, that would be a better optimization. However at this stage, you have a y = SHL(x, 0) + ADD(y, z). I think it makes sense to combine them into one and let DCE take care of it. Ideally we wouldn't get into such a situation, but the real issue is that a perfectly representable (if dumb) instruction like SHLADD(x, 0, y) gets messed up by replaceZero. We should fix replaceZero. We should also try to avoid generating such stupid instructions. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
