Avoid potential slient wrong-code with reg+reg addr. modes on SH.

gcc/
	* config/sh/sh.c (sh_print_operand_address): Don't use hardcoded 'r0'
	for reg+reg addressing mode.

From-SVN: r237088

gcc/ChangeLog

+2016-06-04  Oleg Endo  <olegendo@gcc.gnu.org>
+
+	* config/sh/sh.c (sh_print_operand_address): Don't use hardcoded 'r0'
+	for reg+reg addressing mode.
+
 2016-06-03  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	* rs6000-c.c (c/c-tree.h): Add #include.

gcc/config/sh/sh.c

@@ -1038,8 +1038,16 @@ sh_print_operand_address (FILE *stream, machine_mode /*mode*/, rtx x)
 	      int base_num = true_regnum (base);
 	      int index_num = true_regnum (index);
 
-	      fprintf (stream, "@(r0,%s)",
-		       reg_names[MAX (base_num, index_num)]);
+	      /* If base or index is R0, make sure that it comes first.
+		 Usually one of them will be R0, but the order might be wrong.
+		 If neither base nor index are R0 it's an error and we just
+		 pass it on to the assembler.  This avoids silent wrong code
+		 bugs.  */
+	      if (base_num == 0 && index_num != 0)
+		std::swap (base_num, index_num);
+
+	      fprintf (stream, "@(%s,%s)", reg_names[index_num],
+					   reg_names[base_num]);
 	      break;
 	    }