IRA for GCC 4.4

[Paolo Bonzini]

>> (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)
>>
>>   
> Thanks, I'll check it.

Vlad, I think you should also try to understand what does trunk do with 
  global (and without local allocation) at -O0.  That will give a 
measure of the benefit from Peter's patches for conflict graph building.

Another thing to evaluate is the impact of changing gimplify.c so that 
it always follows the "if (optimize)" paths.  The differences are there 
exactly because we don't run global register allocation at -O0, and they 
create more pseudos.

Paolo