IRA for GCC 4.4

[Vladimir Makarov]

FX wrote:
> I'm willing to try and do some benchmarking of Fortran codes using IRA
> (on i686 and x86_64), and report back here with figures and reduced
> testcases of eventual slow-downs. What is the current, stable way to
> build an IRA compiler and run it? Should I just get the last revision
> of the ira branch? When compiling, are there any options
> necessary/useful?
>
>   
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

I tested IRA mostly on SPEC2000 which, I believe, is a pretty good 
benchmark suite.  It would be interesting how IRA works on other benchmarks.

If you would like to try the mainline, the 2nd version of the patch (I 
sent it a week ago) could be applied but you will need a small fix in 
caller-saves.c.  The difference between in IRA branch and mainline is 
about 3 weeks.  I am going to merge mainline into the branch soon.

I am also going to submit a small patch into the branch on this week 
improving SPECFP2000 performance on ppc about 1% (I did not finished 
patch testing on other ports).  I'll CC it to you.

Vlad