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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/38474] compile time explosion in dataflow_set_preserve_mem_locs at -O3
Date: Wed, 10 Feb 2021 16:06:07 +0000	[thread overview]
Message-ID: <bug-38474-4-MSZTrayDAC@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-38474-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38474

--- Comment #90 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Because it says that the whole range is uninitialized, so the store merging
code doesn't need to care about pre-existing content in any gaps between the
stored values.  So say when the whole var is clobbered and then the code stores
to every second bitfield, we don't need to read the old content, mask it, or
with the stored bits and store that, but can just put some suitable value into
the gaps (0 or all ones or whatever is best).
For quadratic behavior, I wonder if we just shouldn't see how many chains are
we tracking currently and if we have too many (some param), terminate all of
them.

  parent reply	other threads:[~2021-02-10 16:06 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-38474-4@http.gcc.gnu.org/bugzilla/>
2011-04-28 16:04 ` [Bug middle-end/38474] slow compilation at -O0 due to expand's temp slot goo rguenth at gcc dot gnu.org
2011-12-02 13:06 ` steven at gcc dot gnu.org
2011-12-02 13:25 ` matz at gcc dot gnu.org
2012-05-27 23:24 ` steven at gcc dot gnu.org
2012-05-29  7:53 ` Joost.VandeVondele at mat dot ethz.ch
2012-05-29 13:09 ` matz at gcc dot gnu.org
2012-05-29 13:12 ` matz at gcc dot gnu.org
2012-05-29 15:08 ` hubicka at gcc dot gnu.org
2012-05-29 16:00 ` jamborm at gcc dot gnu.org
2012-06-15 14:56 ` matz at gcc dot gnu.org
2012-06-15 15:13 ` matz at gcc dot gnu.org
2012-06-15 15:26 ` Joost.VandeVondele at mat dot ethz.ch
2012-06-26 14:26 ` jamborm at gcc dot gnu.org
2012-06-26 14:45 ` matz at gcc dot gnu.org
2012-06-26 14:58 ` rguenth at gcc dot gnu.org
2012-06-26 15:01 ` jamborm at gcc dot gnu.org
2012-06-29 14:34 ` jamborm at gcc dot gnu.org
2012-07-02 15:28 ` jamborm at gcc dot gnu.org
2012-07-02 15:44 ` jamborm at gcc dot gnu.org
2012-07-02 15:53 ` jamborm at gcc dot gnu.org
2012-08-28  8:25 ` steven at gcc dot gnu.org
2012-08-28 11:28 ` Joost.VandeVondele at mat dot ethz.ch
2012-08-28 14:55 ` Joost.VandeVondele at mat dot ethz.ch
2012-08-28 15:07 ` steven at gcc dot gnu.org
2013-03-06 11:01 ` [Bug middle-end/38474] compile time explosion in dataflow_set_preserve_mem_locs at -O3 steven at gcc dot gnu.org
2013-03-07 10:32 ` rguenth at gcc dot gnu.org
2013-03-07 14:55 ` rguenth at gcc dot gnu.org
2013-12-06 13:43 ` rguenth at gcc dot gnu.org
2013-12-06 14:20 ` rguenth at gcc dot gnu.org
2013-12-09 15:13 ` rguenth at gcc dot gnu.org
2013-12-10 12:31 ` rguenth at gcc dot gnu.org
2021-02-10 14:52 ` rguenth at gcc dot gnu.org
2021-02-10 15:03 ` rguenth at gcc dot gnu.org
2021-02-10 15:46 ` rguenth at gcc dot gnu.org
2021-02-10 15:47 ` rguenth at gcc dot gnu.org
2021-02-10 15:51 ` jakub at gcc dot gnu.org
2021-02-10 15:55 ` rguenther at suse dot de
2021-02-10 16:02 ` rguenth at gcc dot gnu.org
2021-02-10 16:06 ` jakub at gcc dot gnu.org [this message]
2021-02-10 16:06 ` rguenth at gcc dot gnu.org
2021-02-10 16:28 ` rguenth at gcc dot gnu.org
2021-02-10 16:49 ` jakub at gcc dot gnu.org
2021-02-11  9:32 ` rguenth at gcc dot gnu.org
2021-02-12  8:57 ` cvs-commit at gcc dot gnu.org
2021-02-12 10:29 ` rguenth at gcc dot gnu.org
2021-02-12 10:35 ` rguenth at gcc dot gnu.org
2021-02-12 11:42 ` cvs-commit at gcc dot gnu.org
2021-02-12 14:40 ` rguenth at gcc dot gnu.org
2021-02-16 12:38 ` cvs-commit at gcc dot gnu.org
2021-04-29  8:04 ` cvs-commit at gcc dot gnu.org

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