Use partial_subreg_p in curr_insn_transform

Use partial_subreg_p in code that was added since the initial patch
that introduced this function.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* lra-constraints.c (curr_insn_transform): Use partial_subreg_p.

From-SVN: r256194

gcc/ChangeLog

 2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* lra-constraints.c (curr_insn_transform): Use partial_subreg_p.
+
+2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
 

gcc/lra-constraints.c

@@ -4243,8 +4243,7 @@ curr_insn_transform (bool check_only_p)
 			      || (simplify_subreg_regno
 				  (ira_class_hard_regs[goal_alt[i]][0],
 				   GET_MODE (reg), byte, mode) >= 0)))
-		      || (GET_MODE_PRECISION (mode)
-			  < GET_MODE_PRECISION (GET_MODE (reg))
+		      || (partial_subreg_p (mode, GET_MODE (reg))
 			  && GET_MODE_SIZE (GET_MODE (reg)) <= UNITS_PER_WORD
 			  && WORD_REGISTER_OPERATIONS)))
 		{