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From: "dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/109184] New: csmith: really old bug with -O3
Date: Sat, 18 Mar 2023 11:21:55 +0000	[thread overview]
Message-ID: <bug-109184-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109184

            Bug ID: 109184
           Summary: csmith: really old bug with -O3
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 54701
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54701&action=edit
C source code

For the attached C code, compiled with -O2 and -O3, produces different answers:

$ ~/gcc/results/bin/gcc -w -O2 -fno-strict-aliasing bug897.c
$ ./a.out 1 > 1
$ $ ~/gcc/results/bin/gcc -w -O3 -fno-strict-aliasing bug897.c
$ ./a.out 1 > 2
$ diff 1 2 | head
2038c2038
< ...checksum after hashing g_1731[i][j] : 351CD463
---
> ...checksum after hashing g_1731[i][j] : 7739D31E
2040c2040
< ...checksum after hashing g_1731[i][j] : 791FAA71
---
> ...checksum after hashing g_1731[i][j] : FEBF8F12

The bug seems to exist since sometime before 20220403, nearly a year ago.

Flag -ftrivial-auto-var-init=zero doesn't seem to help.

             reply	other threads:[~2023-03-18 11:21 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-18 11:21 dcb314 at hotmail dot com [this message]
2023-03-18 11:33 ` [Bug c/109184] " dcb314 at hotmail dot com
2023-03-18 12:27 ` dcb314 at hotmail dot com
2023-03-18 12:42 ` dcb314 at hotmail dot com
2023-03-18 15:49 ` [Bug tree-optimization/109184] [10/11/12/13 Regression] " jakub at gcc dot gnu.org
2023-03-20  9:20 ` [Bug tree-optimization/109184] [10/11/12/13 Regression] csmith: 2017 bug with -floop-interchange rguenth at gcc dot gnu.org
2023-03-20 10:34 ` rguenth at gcc dot gnu.org
2023-03-20 10:58 ` rguenth at gcc dot gnu.org
2023-03-20 12:39 ` rguenth at gcc dot gnu.org
2023-03-20 12:46 ` jakub at gcc dot gnu.org
2023-03-20 12:50 ` rguenth at gcc dot gnu.org
2023-03-20 13:00 ` rguenth at gcc dot gnu.org
2023-03-20 13:09 ` acoplan at gcc dot gnu.org
2023-03-21 12:38 ` rguenth at gcc dot gnu.org
2023-03-27  7:31 ` rguenth at gcc dot gnu.org
2023-07-07 10:45 ` [Bug tree-optimization/109184] [11/12/13/14 " rguenth at gcc dot gnu.org
2023-11-14 12:44 ` rguenth at gcc dot gnu.org

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