The calculate branch probabilities algorithm (1) in the Wu Larus paper also evenly distributes branch probabilities when number of outgoing edges is > 2, e.g. switch cases implemented as jump tables.
Are they any known heuristics to generate better branch probabilities in this case? -----Original Message----- From: Jan Hubicka [mailto:hubi...@ucw.cz] Sent: 14 April 2010 00:44 To: Rahul Kharche Cc: gcc@gcc.gnu.org; sdkteam-gnu Subject: Re: branch probabilities on multiway branches > Hi All, > > The following bit of code in predict.c implies branch probabilities > are strictly evenly distributed for multiway branches at present. The > comment suggests it is possible to generate better estimates for more > generic cases, apart from being involved. Could anyone point me to > the reference and/or if an implementation exists already. There is Wu & Larus paper cited in the comment at the begging of file. Honza
