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Date: Mon, 19 Jan 2004 23:30:00 -0000
From: Joe Buck <Joe.Buck@synopsys.COM>
To: Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
Cc: s.bosscher@student.tudelft.nl, gcc@gcc.gnu.org
Subject: Re: [RFC] Contributing tree-ssa to mainline
Message-ID: <20040119153026.A21678@synopsys.com>
References: <10401170324.AA15949@vlsi1.ultra.nyu.edu>
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In-Reply-To: <10401170324.AA15949@vlsi1.ultra.nyu.edu>; from kenner@vlsi1.ultra.nyu.edu on Fri, Jan 16, 2004 at 10:24:08PM -0500
X-SW-Source: 2004-01/txt/msg01405.txt.bz2

On Fri, Jan 16, 2004 at 10:24:08PM -0500, Richard Kenner wrote:
>     Expecting tree-ssa to produce code better by a factor of two is simply
>     unreasonable.
> 
> In general, of course.  But if it is really allowing new classes of
> optimizations to be performed (which was the argument to justify the new
> infrastructure), it should be possible to construct test cases that show
> that sort of performance improvement (factors of two or more).

There are certain cases where tree-ssa *already* produces better code by a
factor of two or more.  See, for example PR 12747.