register allocation

[Qiong Cai]

Hi,

I'm going to study register allocation in GCC.  Currently GCC has 
two register allocators.  Here some questions:

* Is there any performance results(eg. spec2k results) available for
these two allocators?
* Besides those ra*.[c,h] files, is tthere any other source files related 
to register allocation?
* Which function, if available, calcuate the register pressure, 
which is the defined as the max number of live variable for a basic block?

Many thanks.

Qiong