RFA: patch for PR3781

[Jeff Law]

Vladimir Makarov wrote:
> The following patch fixes one problem for PR37813.  The description of 
> the problem can be found on
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37813
>
> The patch was successfully bootstrapped and tested on x86/x86_64 and 
> ppc64.
>
> Ok to commit?
>
> 2008-10-22  Vladimir Makarov  <vmakarov@redhat.com>
>
>    PR middle-end/37813
>    * ira-conflicts.c (process_regs_for_copy): Remove class subset
>    check.
>
>    * ira-int.h (ira_hard_regno_cover_class): New.
>
>    * ira-lives.c (mark_reg_live, mark_reg_dead,
>    process_bb_node_lives): Use ira_hard_regno_cover_class.
>
>    * ira.c (reg_class ira_hard_regno_cover_class): New global
>    variable.
>    (setup_hard_regno_cover_class): New function.
>    (ira_init): Call setup_hard_regno_cover_class.
>
>    * ira-costs.c (cost_class_nums): Add comment.
>    (find_allocno_class_costs): Initiate cost_class_nums.
>    (setup_allocno_cover_class_and_costs): Check cost_class_nums.
>
This is fine.

Jeff