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Re: gcc -O1 performs better than gcc -O2

From: Jakub Jelinek <jakub at redhat dot com>
To: Joakim Tjernlund <joakim dot tjernlund at transmode dot se>
Cc: Richard Guenther <richard dot guenther at gmail dot com>, gcc at gcc dot gnu dot org
Date: Sun, 14 Feb 2010 20:21:50 +0100
Subject: Re: gcc -O1 performs better than gcc -O2
References: <OF9B772903.349DEEA1-ONC12576CA.005BC3E4-C12576CA.005CA05B@transmode.se> <84fc9c001002141005w6e432e46y27d1b6ad34ddb49b@mail.gmail.com> <OFC8FD061C.4930B742-ONC12576CA.006812FD-C12576CA.0068F363@transmode.se>
Reply-to: Jakub Jelinek <jakub at redhat dot com>

On Sun, Feb 14, 2010 at 08:06:20PM +0100, Joakim Tjernlund wrote:
> the warmup isn't really needed after I added memset and inline or not should
> not matter that much are only used once so I think my
> conclusion still stands: gcc 4.3.4 is slower with -O2 than -O1

You mean this particular GCC version on this particular benchmark.
You'd need to benchmark orders of magnitude more code to be able to
talk about -O1 vs. -O2 in general.  ;)

	Jakub

Follow-Ups:
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  - From: Joakim Tjernlund

References:
- gcc -O1 performs better than gcc -O2
  - From: Joakim Tjernlund
- Re: gcc -O1 performs better than gcc -O2
  - From: Richard Guenther
- Re: gcc -O1 performs better than gcc -O2
  - From: Joakim Tjernlund

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