Luis Machado wrote:
This is a Power6 4.7Ghz (altivec supported)
Great. Now I have an access to power6. So I am going to try it too.
What options (especially march or mtune) you are using? IRA is very
sensitive to correct times of ld/st/moves in machine description.
I'm currently using two tuning setups.
base flags: -m64 -O2 -mcpu=power4
peak flags: -m64 -O3 -mcpu=power4 -ffast-math -ftree-loop-linear -funroll-loops
-fpeel-loops
What is overall IRA regression on SPEC2000?
I don't have that information on this box yet. But i'll have it soon and
will let you know. Right now i only focused on those two degraded
benchmarks.
You could use the same version of the compiler with IRA (default) and
old RA (-fno-ira).
Thanks for the tip. Is it a good idea to go through the ira-merge branch
as well? Or would this suffice?
H.J. Lu keeps ira-branch merge more fresh than trunk. But the lag is
only 1-3 days usually because gcc community and RA reviewers are very
responsive. So I don't see a big difference in using ira-merge and
trunk. I'd only recommend to apply patch
http://gcc.gnu.org/ml/gcc-patches/2008-09/msg00427.html
first because it is critical for performance but I don't know when it
will be approved.
