From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-361648-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 29164 invoked by alias); 3 Jul 2011 14:39:48 -0000
Received: (qmail 29153 invoked by uid 22791); 3 Jul 2011 14:39:47 -0000
X-SWARE-Spam-Status: No, hits=-2.6 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00,TW_FX,TW_ZJ
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 03 Jul 2011 14:39:33 +0000
From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/49583] Reloading stack operands in the wrong order, so needs to insert fxch
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: ubizjak at gmail dot com
X-Bugzilla-Status: RESOLVED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields: Status Resolution
Message-ID: <bug-49583-4-cHgp8pFW4Z@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-49583-4@http.gcc.gnu.org/bugzilla/>
References: <bug-49583-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Date: Sun, 03 Jul 2011 14:39:00 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2011-07/txt/msg00132.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49583

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |WONTFIX

--- Comment #2 from Uros Bizjak <ubizjak at gmail dot com> 2011-07-03 14:38:54 UTC ---
You should use powf instead of pow. Many of these moves are actually
double->float and float->double x87 conversion instructions.

You can use -ffast-math to avoid these conversions, but using powf on float
values is probably what you want.

Other moves are necessary to pass arguments to the function via stack and to
save live values from registers around the call.

Also, don't worry about fxch or two, these are extremely fast instructions.