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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: Sun, 04 Sep 2005 10:35:00 -0000 [thread overview]
Message-ID: <20050904103538.25175.qmail@sourceware.org> (raw)
In-Reply-To: <20050609222806.21990.bjoern.m.haase@web.de>
------- Additional Comments From bjoern dot m dot haase at web dot de 2005-09-04 10:35 -------
Indeed IMHO the problem stems from the patch:
+2005-01-22 Roger Sayle <roger@eyesopen.com>
+
+ PR middle-end/19378
+ * config/avr/avr.c (avr_hard_regno_mode_ok): Rewrite.
+
IMO the problem stems from the change
- /* Reload can use r28:r29 for reload register and for frame pointer
- in one insn. It's wrong. We must disable it. */
- if (mode != Pmode && reload_in_progress && frame_pointer_required_p ()
- && regno <= REG_Y && (regno + GET_MODE_SIZE (mode)) >= (REG_Y + 1))
+ /* Otherwise disallow all regno/mode combinations that span r28:r29. */
+ if (regno <= (REG_Y + 1) && (regno + GET_MODE_SIZE (mode)) >= (REG_Y + 1))
return 0;
Denis Chertykov's older version using "frame_pointer_required_p ()" has now
vanished. A problem during register allocation has been removed by Roger
Sayle's patch. However, the old frame pointer bug has been re-introduced.
My suggestion is to use the following implementation. (according patch to
today's head attached) This patch has passed regression tests on head without
new regressions on head on the c-testsuite for compilation and simulator
excecution for the atmega128.
I also verified on an old snapshot that had exposed PR21990 that this patch
resolves PR21990.
I'll post this message also on gcc-patches.
Yours,
Bjoern
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21990
next prev parent reply other threads:[~2005-09-04 10:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2005-09-04 11:19 ` giovannibajo at libero dot it
2005-09-04 11:29 ` bjoern dot m dot haase at web dot de
[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
2006-09-19 20:25 ` eweddington at cso dot atmel dot com
2007-08-23 20:39 ` eweddington at cso dot atmel dot com
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