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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/34312] [4.3 regression] spill failure with -O2 -fPIC -march=pentium-m on i386
Date: Wed, 05 Dec 2007 13:55:00 -0000 [thread overview]
Message-ID: <20071205135447.31500.qmail@sourceware.org> (raw)
In-Reply-To: <bug-34312-10561@http.gcc.gnu.org/bugzilla/>
------- Comment #9 from ubizjak at gmail dot com 2007-12-05 13:54 -------
(In reply to comment #8)
> > Instead, -fPIC should unconditionally decrease the available regparm by 1.
> Yes, this seems to be the best solution in the short term.
I'm testing following patch:
Index: i386.c
===================================================================
--- i386.c (revision 130622)
+++ i386.c (working copy)
@@ -3200,7 +3200,7 @@ ix86_function_regparm (const_tree type,
/* Make sure no regparm register is taken by a
global register variable. */
for (local_regparm = 0; local_regparm < 3; local_regparm++)
- if (global_regs[local_regparm])
+ if (global_regs[local_regparm] || fixed_regs[local_regparm])
break;
/* We can't use regparm(3) for nested functions as these use
@@ -3226,7 +3226,7 @@ ix86_function_regparm (const_tree type,
so the more global reg vars there are, the smaller regparm
optimization use, unless requested by the user explicitly. */
for (regno = 0; regno < 6; regno++)
- if (global_regs[regno])
+ if (global_regs[regno] || fixed_regs[regno])
globals++;
local_regparm
= globals < local_regparm ? local_regparm - globals : 0;
The rationale is that fixed reg, as well as global reg should decrease the
number of registers available for argument passing. When %ebx is used as -fpic
reg for 32bit targets, this does exactly what Comment #6 suggests.
This patch of course doesn't lower the importance of the fix for PR 19398. ;)
--
ubizjak at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |ubizjak at gmail dot com
|dot org |
Status|NEW |ASSIGNED
Last reconfirmed|2007-12-03 11:28:04 |2007-12-05 13:54:47
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34312
next prev parent reply other threads:[~2007-12-05 13:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-01 23:17 [Bug target/34312] New: " christophe at saout dot de
2007-12-01 23:19 ` [Bug target/34312] " christophe at saout dot de
2007-12-03 11:25 ` ubizjak at gmail dot com
2007-12-03 11:28 ` [Bug target/34312] [4.3 regression] " ubizjak at gmail dot com
2007-12-03 13:45 ` [Bug rtl-optimization/34312] " ubizjak at gmail dot com
2007-12-03 15:16 ` bonzini at gnu dot org
2007-12-03 16:32 ` rguenth at gcc dot gnu dot org
2007-12-03 17:52 ` rask at gcc dot gnu dot org
2007-12-03 20:48 ` ebotcazou at gcc dot gnu dot org
2007-12-05 13:55 ` ubizjak at gmail dot com [this message]
2007-12-05 16:01 ` uros at gcc dot gnu dot org
2007-12-05 16:03 ` ubizjak at gmail dot com
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