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From: Andrew Thomas Pinski <pinskia@gmail.com>
To: "gcc-bugzilla@gcc.gnu.org" <gcc-bugzilla@gcc.gnu.org>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>
Subject: Re: [Bug tree-optimization/37312] -Os significantly faster than -O2 on test case
Date: Mon, 01 Sep 2008 20:41:00 -0000	[thread overview]
Message-ID: <BDE688DD-188F-440B-A883-B4498C07F542@gmail.com> (raw)
In-Reply-To: <20080901143614.26759.qmail@sourceware.org>

This is mostly because of extra register moves that IRA some times  
introduces. There is another bug about Inline-asm and the return  
register.

Sent from my iPhone

On Sep 1, 2008, at 7:36, "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

>
>
> ------- Comment #4 from rguenth at gcc dot gnu dot org  2008-09-01  
> 14:36 -------
> Well, now -Os -funroll-all-loops doesn't do any unrolling anymore  
> while it did
> before.  With -O2 you get what you ask for - unrolled loops.
>
> -funroll-all-loops isn't really a flag to be used in general.
>
>
> -- 
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37312
>


  reply	other threads:[~2008-09-01 20:41 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-01 11:22 [Bug tree-optimization/37312] New: " andi-gcc at firstfloor dot org
2008-09-01 11:23 ` [Bug tree-optimization/37312] " andi-gcc at firstfloor dot org
2008-09-01 13:43 ` rguenth at gcc dot gnu dot org
2008-09-01 14:21 ` andi-gcc at firstfloor dot org
2008-09-01 14:37 ` rguenth at gcc dot gnu dot org
2008-09-01 20:41   ` Andrew Thomas Pinski [this message]
2008-09-01 20:42 ` [Bug tree-optimization/37312] -Os significantly faster than -O2 on test case wiht -funroll-all-loops pinskia at gmail dot com
2008-09-02 20:46 ` pinskia at gcc dot gnu dot org

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