The following patch should improve code size which degradation for arm 
is reported on

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48455

Is it ok to commit?  The patch was successfully bootstrapped on x86-64 
and i686 with H.J.'s autotester options.

2011-04-13  Vladimir Makarov <vmakarov@redhat.com>

         PR rtl-optimization/48455
         * ira-costs.c (find_costs_and_classes): Use i_mem_cost instead of
         `temp_costs->mem_cost'.