Index: constraints.md
===================================================================
--- constraints.md	(revision 176494)
+++ constraints.md	(working copy)
@@ -127,6 +127,11 @@
   "@internal Constant call address operand."
   (match_operand 0 "constant_call_address_operand"))

+(define_constraint "w"
+  "@internal Call memory operand."
+  (and (match_test "!TARGET_X32")
+       (match_operand 0 "memory_operand"))
+
 ;; Integer constant constraints.
 (define_constraint "I"
   "Integer constant in the range 0 @dots{} 31, for 32-bit shifts."