new-regalloc performance

[Richard Henderson]

You'll want to examine gcc.c-torture/compile/20001226-1.c.

I'd fixed the previous big memory consumers for this test,
but on the branch we're back to eating 470M of memory.

Moreover, (alpha) profile data shows

 global alloc          : 192.79 (69%) usr   1.19 (34%) sys 194.04 (68%) wall
 TOTAL                 : 280.18             3.46           283.75

  %   cumulative   self              self     total           
 time   seconds   seconds    calls  ms/call  ms/call  name    
 67.49    161.15   161.15  2421348     0.07     0.07  varray_contains
  6.60    176.91    15.76        3  5254.88  5281.60  compute_hash_table
  4.68    188.09    11.18       13   859.83   874.58  verify_flow_info

It looks like things could be fixed by using a regset
instead of, or in addition to, a varray.


r~