(movdf): Don't copy a word at a time; nearly always loses.

From-SVN: r10859

gcc/config/rs6000/rs6000.md

@@ -4365,15 +4365,6 @@
   ""
   "
 {
-  if (GET_CODE (operands[0]) == MEM && GET_CODE (operands[1]) == MEM)
-    {
-      emit_move_insn (operand_subword (operands[0], 1, 1, DFmode),
-		      operand_subword_force (operands[1], 1, DFmode));
-      emit_move_insn (operand_subword (operands[0], 0, 1, DFmode),
-		      operand_subword_force (operands[1], 0, DFmode));
-      DONE;
-    }
-
   if (GET_CODE (operands[0]) != REG)
     operands[1] = force_reg (DFmode, operands[1]);