Compilation time has more than doubled on some Polyhedron tests

[Tobias Schlüter]

In looking at compiles times, I missed looking at memory usage:

Dominique Dhumieres wrote:
> On an AMD, the 20060105 build gives
> 
>  tree SSA rewrite      :   0.45 ( 2%) usr   0.02 ( 5%) sys   0.36 ( 2%) wall   35265 kB (27%) ggc
>  tree SSA incremental  :   0.71 ( 4%) usr   0.02 ( 5%) sys   0.77 ( 4%) wall    6145 kB ( 5%) ggc
>  tree operand scan     :   0.44 ( 2%) usr   0.07 (18%) sys   0.55 ( 3%) wall   17385 kB (13%) ggc
>  expand                :   0.39 ( 2%) usr   0.00 ( 0%) sys   0.46 ( 2%) wall    9703 kB ( 8%) ggc
>  TOTAL                 :  19.26             0.40            19.91             129144 kB

20060106:
>  tree SSA rewrite      :   0.93 ( 3%) usr   0.03 ( 8%) sys   1.08 ( 3%) wall   65009 kB (33%) ggc
>  tree SSA incremental  :   1.84 ( 5%) usr   0.02 ( 5%) sys   1.87 ( 5%) wall   13262 kB ( 7%) ggc
>  tree operand scan     :   0.88 ( 3%) usr   0.05 (13%) sys   0.97 ( 3%) wall   29929 kB (15%) ggc
>  expand                :   0.97 ( 3%) usr   0.01 ( 3%) sys   1.01 ( 3%) wall   13943 kB ( 7%) ggc
>  TOTAL                 :  33.82             0.38            34.64             194932 kB

An increase by > 50%.  Here and before I extracted the numbers from your
compilations of induct.f90.

It looks like we're generating significantly more trees now, which would of
course explain the increase in time spent checking.

- Tobi