On Sun, Mar 25, 2012 at 12:22 PM, Jan Hubicka <hubi...@ucw.cz> wrote: >> This patch propagates execution count of thee case labels of a >> switch-case statement after its expansion. Bootstraps and all >> tests pass. OK for trunk? > > Hi, > while this is resonable thing to do, I belive it would make most sense > to make switch lowering at gimple level: i.e. reorganize the existing > code to produce gimple statement and change expansion code to produce > tablejump from every gimple switch statement that was left in the > code. > > This would be both cleaner and would allow gimple optimizers to improve the > generated code. Incrementally it would also allow us to improve switch > exansion > that is quite baroque and not realy producing very good code in some common > cases. > > If you would be interested working on this (i.e. reorganizing the expansion > code to produce gimple), I would be very happy. If not, I can review the > profile updating part for mainline, since in any case this is desriable thing > to do.
I am planning to explore improvements to switch expansion (peeling some cases and using jump tables for the rest, for example) and I think the reorganization you suggest is the right way to do such improvements. But until I can spend time on it and get it done, I would like this patch to get reviewed and checked in. Thanks, Easwaran > Honza
