https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90174
--- Comment #11 from Vladimir Makarov <vmakarov at gcc dot gnu.org> --- (In reply to Tamar Christina from comment #10) > Hi Vlad, > > Just curious if you had a chance to think about an approach to this that > would be acceptable. Sorry for not working on this issue more although I thought about the problem for some time w/o finding any possible small code changes could solve the problem. I just expressed my point of view to the bottom-up approach. If somebody implements any new RA approach which at least does not hurt credible benchmarks (e.g. SPEC) and improve some benchmarks and does not complicate existing RA too much, nobody will have legitimate arguments not to include the new code into GCC. I think that may be for some cases bottom-up approach could work better. Probably this is code for number crunching (with a lot of loop iterations). For some cases top-down approach works better for loops with smaller number iterations (e.g. most loops in GCC itself). Simply, I tried already bottom-up approach and don't want to work on this again because if it does not work I will have to throw this work off again. I am mostly in maintenance mode for GCC RA, don't want to work on big RA changes. This work would be also very hard to sell to my management. If somebody implements bottom-up RA as an optional (or default if it is better on SPEC) algorithm and this improves some benchmarks, I will not object. The work I think would take several months for a person familiar with RA.
