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Re: gcc compile-time performance


In message <20020518.212425.22339908.davem@redhat.com>, "David S. Miller" write
s:
 >    From: Marc Espie <espie@quatramaran.ens.fr>
 >    Date: Sat, 18 May 2002 13:46:43 +0200
 >    
 >    In case you have missed this, I pitted gcc 2.95.3 -O2 against gcc 3.1 -O1
 > ,
 >    to see which one was fastest. On the same source. Something big enough to
 >    be relevant: a BSD kernel.
 >    
 >    gcc 2.95.3 wins hands down, by about 20%.
 >    
 > Hey Marc, could you run your tests with this patch applied
 > to gcc-3.1?  It should kill ~10% or more of the compile time
 > overhead when optimizations are enabled.
 > 
 > 2002-05-17  David S. Miller  <davem@redhat.com>
 > 
 > 	* cselib.c (cselib_invalidate_regno): Only walk over the
 > 	registers we actually need to look at.
Just for reference, a quick test of this on my PAs is showing 1-2% improvements
(I only tried a few files). 

jeff


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