http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37516
--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> 2012-02-23 08:47:55 UTC --- On Thu, 23 Feb 2012, pinskia at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37516 > > Andrew Pinski <pinskia at gcc dot gnu.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > Status|UNCONFIRMED |ASSIGNED > Last reconfirmed| |2012-02-23 > AssignedTo|unassigned at gcc dot |pinskia at gcc dot gnu.org > |gnu.org | > Ever Confirmed|0 |1 > > --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-23 > 08:42:01 UTC --- > I have an idea on how to fix this. > basically: > ~(C - X) > is the same as: > ~ - (X - C) > which then can be simplified to > X - (C+1) > > This should be done on both the tree level (on the pinskia/treecombine branch > in tree-ssa-fold.c) and the rtl level in simplify-rtx.c. Maybe get away with these old-stylish names ('tree' and 'fold') and make it match reality, gimple-ssa-combine.c ;) Still have to have a look at your branch - do you have a brief overview documentation, for example on the wiki? What I'd like to do is have an interface that I can re-use for VN combining, basically replace its simplify_*_expression functions. Richard.
