[Ada] Reset Is_True_Constant on entites used as OUT/IN OUT actuals

2018-10-09  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_ch6.adb (Add_Call_By_Copy_Node,
	Add_Simple_Call_By_Copy_Node, Expand_Call_Helper): Reset
	Is_True_Constant on entities used as Out or In_Out parameters in
	calls.

From-SVN: r264968

gcc/ada/ChangeLog

 2018-10-09  Ed Schonberg  <schonberg@adacore.com>
 
+	* exp_ch6.adb (Add_Call_By_Copy_Node,
+	Add_Simple_Call_By_Copy_Node, Expand_Call_Helper): Reset
+	Is_True_Constant on entities used as Out or In_Out parameters in
+	calls.
+
+2018-10-09  Ed Schonberg  <schonberg@adacore.com>
+
 	* exp_unst.adb (Unnest_Subprogram): Do not load System to obtain
 	the Address entity unless an activation record is being built.
 	Removes useless with_clauses for System when nested subprograms

gcc/ada/exp_ch6.adb

@@ -1442,6 +1442,7 @@ package body Exp_Ch6 is
 
             Kill_Current_Values (Temp);
             Set_Is_Known_Valid (Temp, False);
+            Set_Is_True_Constant (Temp, False);
 
             --  If type conversion, use reverse conversion on exit
 
@@ -1653,6 +1654,7 @@ package body Exp_Ch6 is
          if Ekind (Formal) /= E_In_Parameter then
             Lhs := Outcod;
             Rhs := New_Occurrence_Of (Temp, Loc);
+            Set_Is_True_Constant (Temp, False);
 
             --  Deal with conversion
 
@@ -3431,6 +3433,7 @@ package body Exp_Ch6 is
                   Kill_Current_Values (Ent);
                   Set_Last_Assignment (Ent, Sav);
                   Set_Is_Known_Valid (Ent, False);
+                  Set_Is_True_Constant (Ent, False);
 
                --  For all other cases, just kill the current values