* ssa-dce.c (note_inherently_necessary_set): New function.
        (find_inherently_necessary): Use it.  Do not consider
        NOTEs, CODE_LABELs or BARRIERS are necessary.  Improve
        handling of asms and unspecs.
        (delete_insn_bb): Only delete INSNs, CALL_INSNs or JUMP_INSNs.

From-SVN: r43656