Messages in this thread | | | Date | Thu, 6 Mar 2008 23:06:10 +0100 | From | Andi Kleen <> | Subject | Re: Linux doesn't follow x86/x86-64 ABI wrt direction flag |
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On Thu, Mar 06, 2008 at 12:56:16PM -0800, H. Peter Anvin wrote: > Richard Guenther wrote: > > > >A patched GCC IMHO makes only sense if it is always-on, yet another option > >won't help in corner cases. And corner cases is exactly what people seem > >to care about. For this reason that we have this single release, 4.3.0, > >that > >behaves "bad" is already a problem. > > > > The option will help embedded vendors who can guarantee that it's not a > problem.
For very very low values of "help".
To be realistic it is very unlikely anybody will measure a difference from a few more or a few less clds in a program. It's not that they're expensive instructions and they normally don't happen in inner loops either.
"If you enable this option you will get an optimization that you cannot measure" @)
-Andi
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