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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/107608] [13 Regression] Failure on fold-overflow-1.c and pr95115.c Date: Tue, 10 Jan 2023 14:25:30 +0000 [thread overview] Message-ID: <bug-107608-4-Kvsvkye9eb@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-107608-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107608 --- Comment #21 from Andrew Macleod <amacleod at redhat dot com> --- (In reply to Richard Biener from comment #13) > Yes, the fact that ranger doesn't operate as a usual propagator with a > lattice > makes things very difficult here. Note that my comment referred to code > optimality, not correctness. > > > It really looks like the problem here is DCE (and the gimplifier as you > > point out in comment #2), which is removing a needed statement. Can't this > > be fixed there? > > Sure it can, but the expense is that we'd do constant folding all the way > down and not remove dead code which will result in _tons_ of unnecessary > constant pool entries and loads. > I think I'm missing something, or not understanding what you are saying. Why is the propagation or lack of lattice a problem? Its DCE that is removing that potentially trapping stmt because its no longer used in the IL? THe change would be to not kill off dead statements that may trap? I guess this may leave a bunch of feeding statements that are not dead.. but I fail to see how thats different than not propagating and then not being able to delete those stmts either? > The issue is also that -ftrapping-math is default on so we'd have to > do this by default. Ugh. > > Note that the constant folding routines generally refrain from folding > when that loses exceptions, it's just ranger when producing singleton > ranges and propagating from them that doesn't adhere to that implicit rule. I'm also not sure what this means. I don't think ranger itself propagates singleton constants.. VRP is still using the substitute_and_fold engine, so any folding/propagation is still going through the same mechanisms we always did when a singleton result is produced. We just produce more of them now, especially with floats. I don't think ranger is doing anything different than VRP ever did regarding propagation. Its possible GCCs infrastructure for dealing with float propagation isn't mature enough perhaps?
next prev parent reply other threads:[~2023-01-10 14:25 UTC|newest] Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-11-10 9:47 [Bug tree-optimization/107608] New: [13 Regression] Failure on fold-overflow-1.c jakub at gcc dot gnu.org 2022-11-10 9:49 ` [Bug tree-optimization/107608] " jakub at gcc dot gnu.org 2022-11-10 13:47 ` rguenth at gcc dot gnu.org 2022-11-10 18:13 ` pinskia at gcc dot gnu.org 2022-11-11 7:18 ` pinskia at gcc dot gnu.org 2022-11-13 6:30 ` [Bug tree-optimization/107608] [13 Regression] Failure on fold-overflow-1.c and pr95115.c xry111 at gcc dot gnu.org 2022-11-28 10:06 ` rguenth at gcc dot gnu.org 2022-12-05 13:22 ` aldyh at gcc dot gnu.org 2022-12-05 15:14 ` rguenth at gcc dot gnu.org 2022-12-05 16:30 ` aldyh at gcc dot gnu.org 2022-12-16 13:20 ` jakub at gcc dot gnu.org 2022-12-16 13:32 ` rguenth at gcc dot gnu.org 2023-01-09 15:18 ` aldyh at gcc dot gnu.org 2023-01-10 8:56 ` rguenth at gcc dot gnu.org 2023-01-10 8:58 ` rguenth at gcc dot gnu.org 2023-01-10 10:20 ` aldyh at gcc dot gnu.org 2023-01-10 10:25 ` aldyh at gcc dot gnu.org 2023-01-10 11:00 ` rguenth at gcc dot gnu.org 2023-01-10 11:09 ` jakub at gcc dot gnu.org 2023-01-10 12:08 ` rguenther at suse dot de 2023-01-10 14:14 ` jakub at gcc dot gnu.org 2023-01-10 14:25 ` amacleod at redhat dot com [this message] 2023-01-10 14:33 ` aldyh at gcc dot gnu.org 2023-01-10 14:39 ` jakub at gcc dot gnu.org 2023-01-10 14:40 ` aldyh at gcc dot gnu.org 2023-01-10 14:42 ` jakub at gcc dot gnu.org 2023-01-12 11:42 ` aldyh at gcc dot gnu.org 2023-01-12 12:03 ` jakub at gcc dot gnu.org 2023-01-12 12:26 ` xry111 at gcc dot gnu.org 2023-01-13 13:19 ` aldyh at gcc dot gnu.org 2023-01-13 13:25 ` aldyh at gcc dot gnu.org 2023-01-15 15:43 ` cvs-commit at gcc dot gnu.org 2023-01-16 21:38 ` romain.geissler at amadeus dot com 2023-01-16 21:46 ` jakub at gcc dot gnu.org 2023-01-16 21:55 ` romain.geissler at amadeus dot com 2023-01-16 21:58 ` fw at gcc dot gnu.org 2023-01-18 12:26 ` aldyh at gcc dot gnu.org 2023-01-18 12:54 ` jakub at gcc dot gnu.org 2023-01-18 12:56 ` aldyh at gcc dot gnu.org 2023-01-18 13:00 ` rguenth at gcc dot gnu.org 2023-01-18 13:03 ` rguenth at gcc dot gnu.org 2023-01-18 13:05 ` rguenth at gcc dot gnu.org 2023-01-19 1:15 ` xry111 at gcc dot gnu.org 2023-01-19 7:17 ` rguenther at suse dot de 2023-01-26 14:29 ` xry111 at gcc dot gnu.org 2023-01-27 7:35 ` rguenth at gcc dot gnu.org 2023-01-27 7:59 ` xry111 at gcc dot gnu.org 2023-01-27 9:53 ` rguenther at suse dot de 2023-01-27 10:02 ` xry111 at gcc dot gnu.org 2023-01-27 10:13 ` jakub at gcc dot gnu.org 2023-01-27 11:30 ` rguenther at suse dot de
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