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[Bug middle-end/23181] [4.1 Regression] Slowdown of the bresenham line drawing by roughly 20%
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 10 Nov 2005 18:30:36 -0000
- Subject: [Bug middle-end/23181] [4.1 Regression] Slowdown of the bresenham line drawing by roughly 20%
- References: <bug-23181-176@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #17 from law at redhat dot com 2005-11-10 18:30 -------
Subject: Re: [4.1 Regression] Slowdown of the
bresenham line drawing by roughly 20%
On Wed, 2005-11-02 at 14:32 +0000, hubicka at ucw dot cz wrote:
> Hmm, perhaps restricting the reassociation + simplification into case
> where it kills last use of the intermediate result?
> I can definitly think of testcases where such heuristic would hurt, but
> some experimentation with it would be useful...
> I've looked what the other compilers are doing and except for ICC that
> manages to get even worse code than we do by completely broken if
> conversion all seems to get across that correctly...
And here's the patch. Bootstrapped and regression tested on
i686-pc-linux-gnu:
------- Comment #18 from law at redhat dot com 2005-11-10 18:30 -------
Created an attachment (id=10207)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10207&action=view)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23181