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From: Yury Gribov <y.gribov@samsung.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: [PATCH 0/5] Fix qsort comparison functions
Date: Thu, 17 Dec 2015 08:55:00 -0000	[thread overview]
Message-ID: <5672787D.6040105@samsung.com> (raw)

Hi all,

This patchset fixes bugs in comparison functions used in qsort(3). 
Standard requires comparison functions to satisfy certain 
symmetry/transitivity axioms ("total ordering" in 
http://pubs.opengroup.org/onlinepubs/009695399/functions/qsort.html). 
Violation triggers undefined behavior which can e.g. cause qsort to 
produce invalid results (or even crash - check 
https://bugzilla.samba.org/show_bug.cgi?id=3959).

Most of the patches are pretty obvious except for no. 3 for which I was 
failed to devise a behavior-preserving fix.  I've Cc-ed the original 
authors in hope they'll be able to help.

I've verified all patches on x86_64-pc-linux-gnu (bootstrap + regression 
test).

NB: Bugs were found with SortChecker tool 
(https://github.com/yugr/sortcheck).

/Yury

             reply	other threads:[~2015-12-17  8:55 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-17  8:55 Yury Gribov [this message]
2015-12-17  8:58 ` [PATCH 1/5] Fix asymmetric " Yury Gribov
2015-12-17 11:39   ` Jakub Jelinek
2015-12-17 12:04     ` Yury Gribov
2015-12-18 19:40       ` Yury Gribov
2015-12-18 20:07         ` Jakub Jelinek
2015-12-18 20:09           ` Yury Gribov
2015-12-17 11:41   ` Richard Biener
2015-12-17 11:47     ` Yury Gribov
2015-12-17 11:57       ` Jakub Jelinek
2015-12-17 11:59       ` Richard Biener
2015-12-17 12:14         ` Yury Gribov
2015-12-17 12:25           ` Richard Biener
2015-12-17 12:36             ` Yury Gribov
2015-12-17 11:59   ` Andrey Belevantsev
2015-12-17 12:12     ` Yury Gribov
2015-12-17 12:48       ` Andrey Belevantsev
2015-12-17 19:39   ` Andrew Pinski
2015-12-17 22:00   ` Jason Merrill
2015-12-17  8:59 ` [PATCH 2/5] Fix more " Yury Gribov
2015-12-17  9:00 ` [PATCH 3/5] "Fix" intransitive comparison in reload_pseudo_compare_func Yury Gribov
2015-12-17 19:36   ` Vladimir Makarov
2015-12-18 19:50     ` Yury Gribov
2015-12-17  9:02 ` [PATCH 4/5] Fix intransitive comparison in compare_access_positions Yury Gribov
2015-12-17 14:58   ` Martin Jambor
2015-12-17  9:03 ` [PATCH 5/5] Fix intransitive comparison in dr_group_sort_cmp Yury Gribov
2015-12-17 11:57   ` Richard Biener
2015-12-17 12:33     ` Yury Gribov
2015-12-17 12:51       ` Richard Biener
2015-12-18 20:19         ` Yury Gribov
2015-12-18 22:30           ` Yuri Gribov
2015-12-25 11:42             ` Yury Gribov
2016-01-08  8:23             ` Richard Biener

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