It is more consistent to use them and they are slightly faster to fetch.

An ia32 Load always loads into a GP register.

There are no Copy nodes in the backend this early.

- Tuple nodes can be moved through Perms.
- As side effect, nodes, which produce no value in the current register class, can now be moved through Perms, too.
  In particular, they no longer block moving further nodes.

beloopana: Replace be_new_loop_pressure() by be_new_loop_pressure_cls(), but use the name of the former.

The register class given by the only caller is never null, so be_new_loop_pressure() behaves like be_new_loop_pressure_cls().

Such register classes are flagged manual_ra already.

Further, do not spell it TEMPALTE (sic).

In particular Remove unnecessary tests, whether ia32_get_op_estimated_cost() is called with a non-ia32 node.
Also remove the redundant assert(), which is checked again later on.

4 / 3 * x is x, so use x * 4 / 3.