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From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/46488] [4.5 regression] server/core_filters.c from apache httpd 2.2.17 miscompiled at -O3
Date: Tue, 30 Nov 2010 15:18:00 -0000	[thread overview]
Message-ID: <bug-46488-4-QOn2xOvEJm@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-46488-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46488

--- Comment #32 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-30 15:10:58 UTC ---
The problem appears to be deeply rooted in the Ring construct, more precisely
in the HEAD trick.  IIUC the idea is to "attach" a doubly-linked list to
another structure by means of a "virtual" member overlaid on top of the
structure; the only thing they actually share is a special APR_RING_ENTRY (the
APR_RING_HEAD).  But this overlay fundamentally violates the aliasing rules
even if one try to narrow the accesses to just the shared part.

Richard, is that how the aliasing rules are implemented in the 4.5.x series? 
Has this been changed in 4.6.0?


  parent reply	other threads:[~2010-11-30 15:11 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-15 18:55 [Bug c/46488] New: server/core_filters.c from apache httpd 2.2.17 does not produce good code with optimizations (-O) used on Solaris Sparc 64-bit lk0946 at att dot com
2010-11-16  8:37 ` [Bug middle-end/46488] [4.5 regression] server/core_filters.c from apache httpd 2.2.17 miscompiled with optimization ebotcazou at gcc dot gnu.org
2010-11-16 16:48 ` lk0946 at att dot com
2010-11-16 16:55 ` lk0946 at att dot com
2010-11-16 17:16 ` ebotcazou at gcc dot gnu.org
2010-11-17  0:10 ` lk0946 at att dot com
2010-11-17  0:31 ` ebotcazou at gcc dot gnu.org
2010-11-17  6:43 ` lk0946 at att dot com
2010-11-17  7:44 ` ebotcazou at gcc dot gnu.org
2010-11-25 16:06 ` rguenth at gcc dot gnu.org
2010-11-25 16:58 ` ebotcazou at gcc dot gnu.org
2010-11-26 22:34 ` lk0946 at att dot com
2010-11-26 23:09 ` [Bug middle-end/46488] server/core_filters.c from apache httpd 2.2.17 miscompiled with optimization -O3 rguenth at gcc dot gnu.org
2010-11-27  0:12 ` lk0946 at att dot com
2010-11-27 14:11 ` ebotcazou at gcc dot gnu.org
2010-11-27 23:59 ` LpSolit at netscape dot net
2010-11-28  9:49 ` [Bug middle-end/46488] [4.5 regression] server/core_filters.c from apache httpd 2.2.17 miscompiled at -O3 ebotcazou at gcc dot gnu.org
2010-11-28 13:22 ` ebotcazou at gcc dot gnu.org
2010-11-28 14:33 ` ebotcazou at gcc dot gnu.org
2010-11-29 11:05 ` jorton at redhat dot com
2010-11-29 11:59 ` ebotcazou at gcc dot gnu.org
2010-11-29 12:10 ` jorton at redhat dot com
2010-11-29 13:34 ` ebotcazou at gcc dot gnu.org
2010-11-29 14:03 ` rguenth at gcc dot gnu.org
2010-11-29 14:07 ` rguenth at gcc dot gnu.org
2010-11-29 14:31 ` jorton at redhat dot com
2010-11-29 14:41 ` rguenther at suse dot de
2010-11-29 21:39 ` pcpa at mandriva dot com.br
2010-11-30  7:47 ` ebotcazou at gcc dot gnu.org
2010-11-30 10:00 ` ebotcazou at gcc dot gnu.org
2010-11-30 10:57 ` rguenth at gcc dot gnu.org
2010-11-30 13:14 ` ebotcazou at gcc dot gnu.org
2010-11-30 15:18 ` ebotcazou at gcc dot gnu.org [this message]
2010-11-30 15:47 ` rguenther at suse dot de
2010-11-30 23:43 ` pcpa at mandriva dot com.br
2010-11-30 23:52 ` ebotcazou at gcc dot gnu.org
2010-12-01 10:13 ` rguenther at suse dot de
2010-12-01 12:15 ` ebotcazou at gcc dot gnu.org
2010-12-01 18:23 ` pcpa at mandriva dot com.br
2010-12-01 18:26 ` pcpa at mandriva dot com.br
2010-12-01 18:56 ` ebotcazou at gcc dot gnu.org
2010-12-01 21:54 ` ebotcazou at gcc dot gnu.org
2010-12-01 22:15 ` rguenth at gcc dot gnu.org

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