> -----Original Message----- > From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-ow...@gcc.gnu.org] On > Behalf Of Bin Cheng > Sent: Tuesday, March 26, 2013 4:33 PM > To: 'Joern Rennecke' > Cc: gcc-patches@gcc.gnu.org; 'Jeff Law' > Subject: RE: [PATCH GCC]Relax the probability condition in CE pass when > optimizing for code size > > > > > -----Original Message----- > > From: Joern Rennecke [mailto:joern.renne...@embecosm.com] > > Sent: Monday, March 25, 2013 8:53 PM > > To: Bin Cheng > > Cc: gcc-patches@gcc.gnu.org > > Subject: Re: [PATCH GCC]Relax the probability condition in CE pass > > when optimizing for code size > > > > Quoting Bin Cheng <bin.ch...@arm.com>: > > > > > During the work I observed passes before combine might interfere > > > with CE pass, so this patch is enabled for ce2/ce3 after combination pass. > > > > > > It is tested on x86/thumb2 for both normal and Os. Is it ok for trunk? > > > > There are bound to be target and application specific variations on > > which scaling factors work best. > > > > > 2013-03-25 Bin Cheng <bin.ch...@arm.com> > > > > > > * ifcvt.c (ifcvt_after_combine): New static variable. > > > > It would make more sense to pass in the scale factor as a an argument > > to if_convert. And get the respective values from a set of gcc > > parameters, > so > > they can be tweaked by ports and/or by a user/ML learning framework (e.g. > > Milepost) supplying the appropriate --param option. > > I agree it would be more flexible to pass the factor as parameter, but not > sure how useful to users it will be because: firstly it has already been > target specific by the BRANCH_COST heuristic; for code size, the heuristic > should be tuned to achieve an overall good results, I doubt to which extend it > depends on specific target/application. > > Hi Jeff, > This is based on your heuristic tuning in ifcvt, would you help us on this > issue with some suggestions?
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