[Ada] Spurious warning about change of representastion in call

2019-12-12  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch13.adb (Same_Reprewentation): if the actual in a call is
	a generic actual type, use its bsae type to determine whether a
	change of representastion may be necessary for proper parameter
	passing.

From-SVN: r279305

gcc/ada/ChangeLog

 2019-12-12  Ed Schonberg  <schonberg@adacore.com>
 
+	* sem_ch13.adb (Same_Reprewentation): if the actual in a call is
+	a generic actual type, use its bsae type to determine whether a
+	change of representastion may be necessary for proper parameter
+	passing.
+
+2019-12-12  Ed Schonberg  <schonberg@adacore.com>
+
 	* sem_type.adb (Find_Unique_Type): A call to the universal
 	access equality operator requires one operand to be a universal
 	access, and the other to be an access type. There is no

gcc/ada/sem_ch13.adb

@@ -13448,6 +13448,14 @@ package body Sem_Ch13 is
         and then Base_Type (T1) = Full_View (Base_Type (T2))
       then
          return True;
+
+      --  If T2 is a generic actual it is declared as a subtype, so
+      --  check against its base type.
+
+      elsif Is_Generic_Actual_Type (T1)
+        and then Same_Representation (Base_Type (T1), T2)
+      then
+         return True;
       end if;
 
       --  Tagged types always have the same representation, because it is not