-march=pentium2 + -mtune=pentium4 faster then -march=pentium4?

Gunther Nikl gni at gecko.de
Tue Mar 28 07:59:12 UTC 2006


On Mon, Mar 27, 2006 at 02:20:44PM -0500, Kris Kennaway wrote:
> On Mon, Mar 27, 2006 at 01:05:13PM -0600, Nikolas Britton wrote:
> > Why does GCC produce faster code using "-march=pentium2
> > -mtune=pentium4" on a Pentium 4 chip versus plain -march=pentium4?
> > 
> > Try it...
> > 
> > CPUTYPE=pentium2
> > CFLAGS+= -mtune=pentium4
> > COPTFLAGS+= -mtune=pentium4
> 
> Talk to the gcc developers (and provide benchmarks). 

If this is about GCC 3.4 then don't bother posting on the GCC ML. The 3.4
branch is closed. You must use newer versions or better GCC mainline svn.

Gunther


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