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Article #61Re: [Altivec Newbie] optimizing current code?
From: Darrin Cardani
Date: Fri, 19 Jan 2001 14:48
Date: Fri, 19 Jan 2001 14:48
32 lines
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2782 bytes
In article <Pine.SGI.4.30.0101171735050.41019-100000@helix2.caltech.edu>, Ian Ollmann <iano@cco.caltech.edu> wrote: > On Wed, 17 Jan 2001, Darrin Cardani wrote: > > > Personally, I try to keep things to one AltiVec instruction per line. > > It helps me optimize later, but there's no reason you have to do it > > that way. > > CodeWarrior does a reasonable job at scheduling if you write in C, so I am > curious how keeping things one per line helps you optimize. It helps me (not the compiler) understand what's going on better. I'm better able to see all the instructions, and on a few occasions, I've noticed that I could eliminate an instruction or replace a couple of instructions with fewer instructions. I didn't mean to imply that the compiler does anything different. Sorry if that's what it sounded like. And yes, CodeWarrior does do a good job of scheduling. Or maybe, I just do a bad job of it since I haven't read much about it. :-) Although, I found on a few projects that CW's scheduling by itself made the code slower, but with optimizations turned up all the way made it better. So, as always, profile to be sure. Darrin -- Darrin Cardani Buena Software, Inc. - Macintosh Video, Graphics and Audio Contract Development http://www.buena.com/ dcardani@buena.com
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