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Re: IRA for GCC 4.4
> The best way to test IRA is to build and use the branch. It is easy to
> compare the old RA (which is the default on the branch) and IRA (-fira
> option switches IRA on). I'd recommend to try the following option sets:
> -fira
> -fira -fira-algorithm=CB
OK, I've done that and I see a 40% to 60% increase in compilation time
for the first (Fortran) testcase I tried, is that expected?
With the compiler from the ira branch on x86_64-linux, here are the
timings reported by "gfortran -c -time -save-temps" with and without
IRA (two timings provided for each set of option, to check
reproducability):
With -O0
# f951 148.97 9.92
# as 3.95 0.18
# f951 137.51 7.05
# as 3.98 0.17
With -O0 -fira
# f951 223.89 10.91
# as 3.67 0.18
# f951 218.98 8.43
# as 3.61 0.19
-O0 -fira -fira-algorithm=CB
# f951 191.32 9.03
# as 3.65 0.15
# f951 190.92 8.96
# as 3.63 0.18
(The testcase is 400k lines of preprocessed Fortran code, 16M is size,
available here:
http://www.pci.unizh.ch/vandevondele/tmp/all_cp2k_gfortran.f90.gz)
FX
--
FX Coudert
http://www.homepages.ucl.ac.uk/~uccafco/