On Sun, Nov 22, 2020 at 12:13:46PM -0800, Linus Torvalds wrote: > > Honestly, particularly in the conditional form, the OP_SEL > optimization might not even be the right thing. It adds register > pressure. > > So maybe a better model would be to not try to do jump-conversion, but > have some kind of general "can we simplify phi nodes", where jump > conversion to OP_SEL is just one of the options. Yes, for the "context imbalance" problem, it's best to eliminate the most possible conditional branches (and if-conversion and jump threading help each other at this (when not blocking each other)). So, yes, probably what's missing the most is some strategy to attack the problem. -- Luc
