cse.c: Update comments.

cse.c: Update comments.

        * cse.c: Update comments.
        (cse_insn): When converting a conditional/computed jump into
        an unconditional jump, always make sure a BARRIER immediately
        follows the converted jump.  Do not delete unreachable code.
        (cse_basic_block): Do not delete unreachable code.
        * toplev.c (rest_of_compilation): Move call to
        delete_trivially_dead_insns after the conditional call to
        jump_optimize.

From-SVN: r29665