* ree.c (get_sub_rtx): New function, extracted from...
        (merge_def_and_ext): Here.
        (combine_reaching_defs): Use get_sub_rtx.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@206454 138bc75d-0d04-0410-961f-82ee72b054a4