[Ada] Deep copy operands of membership operations for unnesting

2018-07-16  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_ch4.adb (Expand_Set_Membership): Use New_Copy_Tree to perform a
	deep copy of the left operand when building each conjuct of the
	expanded membership operation, to avoid sharing nodes between them.
	This sharing interferes with the unnesting machinery and is generally
	undesirable.

From-SVN: r262727

gcc/ada/ChangeLog

 2018-07-16  Ed Schonberg  <schonberg@adacore.com>
 
+	* exp_ch4.adb (Expand_Set_Membership): Use New_Copy_Tree to perform a
+	deep copy of the left operand when building each conjuct of the
+	expanded membership operation, to avoid sharing nodes between them.
+	This sharing interferes with the unnesting machinery and is generally
+	undesirable.
+
+2018-07-16  Ed Schonberg  <schonberg@adacore.com>
+
 	* exp_unst.adb (Visit_Node): Handle 'Address references that are
 	calls.
 

gcc/ada/exp_ch4.adb

@@ -12248,7 +12248,7 @@ package body Exp_Ch4 is
 
       function Make_Cond (Alt : Node_Id) return Node_Id is
          Cond : Node_Id;
-         L    : constant Node_Id := New_Copy (Lop);
+         L    : constant Node_Id := New_Copy_Tree (Lop);
          R    : constant Node_Id := Relocate_Node (Alt);
 
       begin