On Wed, 25 Sep 2019, Prathamesh Kulkarni wrote: > On Fri, 20 Sep 2019 at 15:20, Jeff Law <l...@redhat.com> wrote: > > > > On 9/19/19 10:19 AM, Prathamesh Kulkarni wrote: > > > Hi, > > > For PR91532, the dead store is trivially deleted if we place dse pass > > > between ifcvt and vect. Would it be OK to add another instance of dse > > > there ? > > > Or should we add an ad-hoc "basic-block dse" sub-pass to ifcvt that > > > will clean up the dead store ? > > I'd hesitate to add another DSE pass. If there's one nearby could we > > move the existing pass? > Well I think the nearest one is just after pass_warn_restrict. Not > sure if it's a good > idea to move it up from there ?
You'll need it inbetween ifcvt and vect so it would be disabled w/o vectorization, so no, that doesn't work. ifcvt already invokes SEME region value-numbering so if we had MESE region DSE it could use that. Not sure if you feel like refactoring DSE to work on regions - it currently uses a DOM walk which isn't suited for that. if-conversion has a little "local" dead predicate compute removal thingy (not that I like that), eventually it can be enhanced to do the DSE you want? Eventually it should be moved after the local CSE invocation though. Richard.
