-mpower4 sched2 bug miscompiles linux kernel

[David Edelsohn]

	Why shouldn't the string case be organized like:

        src = adjust_address (orig_src, mode, offset);
        dest = adjust_address (orig_dest, mode, offset);
        if (mode == BLKmode)
	  {
            if (!REG_P (src))
	      src = copy_addr_to_reg (XEXP (src, 0));
            if (!REG_P (dest))
              dest = copy_addr_to_reg (XEXP (dest, 0));
            emit_insn ((*gen_func.movstrsi) (dest, src,
                                             GEN_INT (move_bytes & 31),
                                             align_rtx));
          }
        else
          {
            rtx tmp_reg = gen_reg_rtx (mode);
            emit_insn ((*gen_func.mov) (tmp_reg, src));
            emit_insn ((*gen_func.mov) (dest, tmp_reg));
          }

David