On May 29, 2019 10:21:46 PM GMT+02:00, Jeff Law <l...@redhat.com> wrote: >On 5/24/19 6:45 AM, Richard Biener wrote: >[ Aggressive snipping ] > >> As said in my first review I'd just check whether for the >> edge we want to thread through the definition comes from a CMP. >> Suppose you have >> >> # val_1 = PHI <a_2, b_3, c_4> >> if (val_1 != 0) >> >> and only one edge has a b_3 = d_5 != 0 condition it's still >> worth tail-duplicating the if block. >Agreed. The cost of tail duplicating here is so small we should be >doing it highly aggressively. About the only case where we might not >want to would be if we're optimizing for size rather than speed. That >case isn't clearly a win either way.
Even there the PHI likely causes edge copies to be inserted. So I wouldn't care for the moment. The proper check would be ! Optimize_edge_for_size_p (e). Richard. >jeff
