Segher Boessenkool <seg...@kernel.crashing.org> writes: > Hi! > > On Tue, Oct 24, 2023 at 07:49:10PM +0100, Richard Sandiford wrote: >> This patch adds a combine pass that runs late in the pipeline. > > But it is not. It is a completely new thing, and much closer to > fwprop than to combine, too.
Well, it is a combine pass. It's not a new instance of the pass in combine.cc, but I don't think that's the implication. We already have two combine passes: the combine.cc one and the postreload one. Similarly we have at least two DCE implementations. > Could you rename it to something else, please? Something less confusing > to both users and maintainers :-) Do you have any suggestions? >> There are two instances: one between combine and split1, > > So, what kind of things does this do that the real combine does not? > And, same question but for fwprop. That would be the crucial motivation > for why we want to have this new pass at all :-) You've already responded (below) to the part where I explained that. >> The pass currently has a single objective: remove definitions by >> substituting into all uses. > > The easy case ;-) And the yet a case that no existing pass handles. :) That's why I'm trying to add something that does. Richard
