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From: "bjoern dot m dot haase at web dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/21990] Wrong code for 4.0 and head: Reload clobbers the frame pointer by using it as spill register without recognizing the clobbering
Date: Tue, 19 Sep 2006 20:16:00 -0000 [thread overview]
Message-ID: <20060919201637.27903.qmail@sourceware.org> (raw)
In-Reply-To: <bug-21990-9887@http.gcc.gnu.org/bugzilla/>
------- Comment #13 from bjoern dot m dot haase at web dot de 2006-09-19 20:16 -------
Hello Eric,
IIRC, the bug never was really resolved. The true place to fix the issue was,
IMO, the most dreaded source file of the entire GCC source tree: reload.
My now quite old patch tried to fix the immediate problem without touching
reload and it used a fairly crude method by denying gcc to make use of Y in
many situations.
My test case generated code that was very difficult to handle by the register
allocator. This code triggered the bug. Later on some change in some of the
passes just before the 4.0.0 release removed the immediate problem. With 4.0
and afterwards I no longer succeeded to reproduce the bug:
The reason might be, that the original reload bug was fixed.
The reason might as well be that the reload bug is still there, but that it's
no longer exposed due to some other modification in the compiler.
The message is: There stand good chances that this bug is resolved, but I
cannot prove it.
In any case, I'd like to suggest *NOT* to make use of my old crude patch. IMO
it's better to just hope that the problem is fixed.
Until now, I never again stepped over this bug, so I have good confidence.
HTH,
Bjoern
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21990
next prev parent reply other threads:[~2006-09-19 20:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-21990-9887@http.gcc.gnu.org/bugzilla/>
2006-09-19 19:41 ` eweddington at cso dot atmel dot com
2006-09-19 20:16 ` bjoern dot m dot haase at web dot de [this message]
2006-09-19 20:25 ` eweddington at cso dot atmel dot com
2007-08-23 20:39 ` eweddington at cso dot atmel dot com
2005-06-09 22:28 [Bug middle-end/21990] New: " bjoern dot m dot haase at web dot de
2005-06-09 22:32 ` [Bug middle-end/21990] " bjoern dot m dot haase at web dot de
2005-06-09 22:33 ` pinskia at gcc dot gnu dot org
2005-06-10 12:10 ` bjoern dot haase at de dot bosch dot com
2005-06-15 3:22 ` pinskia at gcc dot gnu dot org
2005-07-29 20:53 ` bjoern dot m dot haase at web dot de
2005-08-20 13:54 ` bjoern dot m dot haase at web dot de
2005-09-03 14:25 ` bjoern dot m dot haase at web dot de
2005-09-04 10:35 ` bjoern dot m dot haase at web dot de
2005-09-04 11:19 ` giovannibajo at libero dot it
2005-09-04 11:29 ` bjoern dot m dot haase at web dot de
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