------- Additional Comments From joern dot rennecke at st dot com 2005-01-17 14:18 ------- Subject: Re: delete_trivially_dead_insns fails to update the liveness information
steven at gcc dot gnu dot org wrote: >------- Additional Comments From steven at gcc dot gnu dot org 2005-01-15 >12:29 ------- >Test case??? > I had a test case for this, but this wouldn't reproduce the problem on mainline because most of the functionality of delete_trivially_dead_insns has been disabled by a clumsy patch; see PR 18992 . > >There are many other problems with delete_trivially_dead_insns, unsurprisingly, >so maybe the whole thing should be revisited and reconsidered :-/ > What other problems are there with delete_trivially_dead_insns? As far as I am aware, delete_trivially_dead_insns only needed maitenance when the semantics of the rtl was changed (e.g. adding exceptions), it was called in new contexts (e.g. after flow), or a previous modification wasn't (quite) right / sufficient. In terms of time and code complexity versus optimization result, I think delete_trivially_dead_insns compares quite favourably with running a full data flow and dead code elimination pass. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18995
