Re: [E-devel] [PATCH] evas2 configuration

[Nathan I. <ningerso@d.umn.edu>]

On Thu, Jun 20, 2002 at 12:03:37PM -0400, Val...@vt... is quoted as saying:
> 
> Well, a few minutes of UTSL found this in the GCC 3.1 source tree (in
> gcc/toplev.c near line 337)):
> 
> /* Nonzero means do optimizations.  -O.
>    Particular numeric values stand for particular amounts of optimization;
>    thus, -O2 stores 2 here.  However, the optimizations beyond the basic
>    ones are not controlled directly by this variable.  Instead, they are
>    controlled by individual `flag_...' variables that are defaulted
>    based on this variable.  */
> 
> int optimize = 0;
> 
> and this near line 4724:
> 
>   if (optimize >= 3)
>     {
>       flag_inline_functions = 1;
>       flag_rename_registers = 1;
>     }
> 
> So -O9 does the same as "-O3 -finline-functions -frename-registers". Most
> likely, your added performance boost is due to one of those two.
> 
> -- 
> 				Valdis Kletnieks
> 				Computer Systems Senior Engineer
> 				Virginia Tech
> 

Erm, if that block of code was the difference why would -O9 be any different
than -O3 (note the >= 3)?

I know, I know, get off my ass and look into it myself.

RbdPngn

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|   Nathan Ingersoll             |   Computer Science/Mathematics         |
|   mailto: ningerso@d.umn.edu   |   University of Minnesota-Duluth       |
|   http://umn.edu/~ningerso     |   http://www.d.umn.edu                 |
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