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-march=i686 on i686 ?!?
- To: gcc at gcc dot gnu dot org
- Subject: -march=i686 on i686 ?!?
- From: Paolo Carlini <pcarlini at unitus dot it>
- Date: Tue, 03 Jul 2001 20:06:47 +0200
- CC: dnovillo at redhat dot com
Hi all,
lately I started bothering the list about my own strange benchmarking
issues...
This one my perhaps interest a few more people: when exactly specifying
-march=i686 (on a i686) is supposed to lead to appreciably better
performing code?
In my personal experience (unexpectedly) many of the widespread short
benchmarks do not improve when -march=i686 is added to the command line.
But this is not very relevant. What is more relevant, I think, is that
also many reported benchmarks results for x86 are obtained with the -O2
or -O3 switches and do not discuss at all the particular x86
architecture. This seems strange to me...
Could someone in the known, explain a little bit of this?? I think may
be of interest to many users.
Thanks,
Paolo.