https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110423
--- Comment #3 from Vineet Gupta <vineetg at gcc dot gnu.org> --- (In reply to Jeffrey A. Law from comment #2) > This is derived heavily from Click's work in the 90s. > This would happen in gimple most likely, though I guess one could do it in > RTL if they have a high pain threshold. If a gimple pass, it won't help catch the late reload induced rematerializations, which is seen on a lot of SPEC workloads, e.g. cactu for stack addressing. Although I guess Manolis' fold const offset pass patch would help things a bit. > Click's paper is much more general, but the same concepts apply. His paper > doesn't cover anything like bifurcating the graph (thus allowing multiple > constant loads in an effort to reduce undesired speculation or register > allocation conflicts). > > We might be able to get away with this precisely because these are constant > loads and thus subject to rematerialization later if register pressure is > high. > > https://courses.cs.washington.edu/courses/cse501/06wi/reading/click-pldi95. > pdf The prospect of implementing Cliff's Global Value Numbering is very exciting, however I would like to start small. Started digging into gcse.cc Hoist pass, granted this is still pre-reload. It seems Hoist has some global redundancy elimination capabilities for constants, added by Maxim Kuvyrkov back in 2010. I need to see what it can and can not do.
