------- Comment #23 from zadeck at naturalbridge dot com 2007-12-14 20:07 ------- Subject: Re: [4.3 regression] bad interaction between DF and SJLJ exceptions
joel at gcc dot gnu dot org wrote: > ------- Comment #22 from joel at gcc dot gnu dot org 2007-12-14 20:00 ------- > (In reply to comment #21) > >> I am confused about comment #20. Are these constraint failures caused by the >> proposed patch? are they independent of the patch? why is this related to the >> performance issues in doing SJLJ analysis? >> > > I do not have the proposed patch applied. I only mentioned this because in > addition to the performance issue, there may also be a correctness issue. If > you think it is unrelated, I will file a separate PR. > > > I see no reason to believe that the two are related. I think that the current pr is a combination of four factors: 1) Each step of our analysis is a little more expensive than flow was. 2) We also always solve the forwards problem and the predataflow merge only did this for register allocation. 3) We may have some issues in ordering the nodes that we process. 4) We do not give up until the solution is found. It is possible that there is some interaction with the fact that we are solving the intersection of forwards live and backwards live rather than just relying on backwards live. But even if that is the issue, it should be treated as a separate problem. Kenny -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34400
