[RS6000] Correct constraints for ior<mode>_mask

ior<mode>_mask always splits to rtl matching rotl<mode>3_insert.  The
latter requires one of its input operands match the output, so let
reload/lra know the equivalent operand match must also occur for
ior<mode>_mask.

	PR target/67356
	* config/rs6000/rs6000.md (ior<mode>_mask): Use constraint "0"
	for operand 1.

From-SVN: r227260

gcc/ChangeLog

+2015-08-27  Alan Modra  <amodra@gmail.com>
+
+	PR target/67356
+	* config/rs6000/rs6000.md (ior<mode>_mask): Use constraint "0"
+	for operand 1.
+
 2015-08-27  Richard Biener  <rguenther@suse.de>
 
 	* passes.c (rest_of_decl_compilation): Guard early_global_decl

gcc/config/rs6000/rs6000.md

@@ -3683,7 +3683,7 @@
 ; an insert instruction, in many cases.
 (define_insn_and_split "*ior<mode>_mask"
   [(set (match_operand:GPR 0 "gpc_reg_operand" "=r")
-	(ior:GPR (match_operand:GPR 1 "gpc_reg_operand" "r")
+	(ior:GPR (match_operand:GPR 1 "gpc_reg_operand" "0")
 		 (match_operand:GPR 2 "const_int_operand" "n")))
    (clobber (match_scratch:GPR 3 "=r"))]
   "!logical_const_operand (operands[2], <MODE>mode)