On Sun, 19 Nov 2023, Jeff Law wrote: > OK. Just curious are y'all seeing significant interest in this case from > customers or is this more a case of rounding out the implementation to cover > all potential possibilities?
As in the cover letter: we have a case where the pipeline seems to imply high enough a branch penalty for branchless alternatives to be worth considering even where built from more than just a couple instructions. We yet have to fully evaluate it for our case and it may be that these sequences are costlier than branches after all or that the boundary lies somewhere in between (or that we end up with Zicond also available in the CPU RTL). However we realised that combined with `-mbranch-cost=' it might be a useful tool for performance evaluation for other people as well. This, combined with the branch costing issues observed earlier and attempted to address with 09/44, is also why I chose, conservatively, to add the `-mmovcc' option to control this feature: we may choose to flip it on by default for some tuning architectures or even globally at one point. Especially as it seems like the `addMODEcc' part could be profitable for some architectures already. Maciej
