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rapunzelcardoso
n00b
Joined: 26 May 2010
Posts: 3
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 Posted: Tue Feb 08, 2011 5:05 am Post subject: Use of a specific gcc O3 flag on AMD64 architecture |
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| Hello, followers of the cow. I've read that the -O3 gcc flag enables optimizations that basically fuck up. Now, i've saw exactly what those optimizations are and one is to do crazy inlining and other one is to use more registers on architectures with many registers (-frename-registers). So, since -03 by itself is said to be evil but -frename-registers should be advantageous on amd64 since it has some registers (at least more than x86 so I'm thinking it qualifies as good for the flag), anyone knows if 02 + -frename-registers is safe? I know that safe is a poorly defined word so let's say "safe so that it doesn't fuck up more than 1 application in 100". Hugs to everybody that follows Larry the cow. |
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salahx
Guru
Joined: 12 Mar 2005
Posts: 559
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| Posted: Tue Feb 08, 2011 5:30 am Post subject: |
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On amd64 -frename-registers is already enabled.
You can see exactly what optimization are included in -O2 with
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gcc -O2 -Q --help=optimizers
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rapunzelcardoso
n00b
Joined: 26 May 2010
Posts: 3
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| Posted: Tue Feb 08, 2011 5:44 am Post subject: |
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| salahx wrote: | On amd64 -frename-registers is already enabled.
You can see exactly what optimization are included in -O2 with
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gcc -O2 -Q --help=optimizers
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Thank you salahx |
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pilla
Bodhisattva
Joined: 07 Aug 2002
Posts: 7731
Location: Underworld
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| Posted: Fri Mar 11, 2011 1:46 pm Post subject: |
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Moved from Gentoo Chat to Gentoo on AMD64.
_________________
"I'm just very selective about the reality I choose to accept." -- Calvin |
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Gentoo on AMD64
