(clear_reload_reg_in_use): New function.
(allocate_reload_reg): Don't consider an inherited register as one that we
should share in the first pass.
Don't mark a register in use until we are sure it will fit.
(choose_reload_regs): Mark spill regs used for inheriting.
When we decide we can no longer use a register, show it isn't being used.

From-SVN: r3991