gcc: xtensa: fix NAND code in xtensa_expand_atomic

NAND is ~(a1 & a2), but xtensa_expand_atomic does ~a1 & a2.
That fixes libatomic tests atomic-op-{1,2}.

gcc/
2018-09-04  Max Filippov  <jcmvbkbc@gmail.com>

	* config/xtensa/xtensa.c (xtensa_expand_atomic): Reorder AND and
	XOR operations in NAND case.

From-SVN: r264087

gcc/ChangeLog

+2018-09-04  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* config/xtensa/xtensa.c (xtensa_expand_atomic): Reorder AND and
+	XOR operations in NAND case.
+
 2018-09-04  Aldy Hernandez  <aldyh@redhat.com>
 
 	* wide-int-range.cc (wide_int_range_convert): New.

gcc/config/xtensa/xtensa.c

@@ -1614,9 +1614,9 @@ xtensa_expand_atomic (enum rtx_code code, rtx target, rtx mem, rtx val,
       break;
 
     case MULT: /* NAND */
-      tmp = expand_simple_binop (SImode, XOR, old, ac.modemask,
+      tmp = expand_simple_binop (SImode, AND, old, val,
 				 NULL_RTX, 1, OPTAB_DIRECT);
-      tmp = expand_simple_binop (SImode, AND, tmp, val,
+      tmp = expand_simple_binop (SImode, XOR, tmp, ac.modemask,
 				 new_rtx, 1, OPTAB_DIRECT);
       break;