[Ada] Expansion of discrete choices

This patch does some minor bookkeeping to avoid a potential double expansion
of discrete choices where at least one of them is a subtype with predicates.
No change in behavior, no need for a test.

2018-05-24  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* exp_util.adb (Expand_Static_Predicates_In_Choices): Indicate that the
	construct with discrete choices no longer contains a subtype with
	predicates since the expansion already handled this case.

From-SVN: r260646

gcc/ada/ChangeLog

 2018-05-24  Hristian Kirtchev  <kirtchev@adacore.com>
 
+	* exp_util.adb (Expand_Static_Predicates_In_Choices): Indicate that the
+	construct with discrete choices no longer contains a subtype with
+	predicates since the expansion already handled this case.
+
+2018-05-24  Hristian Kirtchev  <kirtchev@adacore.com>
+
 	* freeze.adb (Wrap_Imported_Subprogram): Generate an unchecked
 	conversion to the return type to avoid a side effect where an imported
 	relocated function generates a new anonymous access type, whose

gcc/ada/exp_util.adb

@@ -4995,6 +4995,8 @@ package body Exp_Util is
 
          Choice := Next_C;
       end loop;
+
+      Set_Has_SP_Choice (N, False);
    end Expand_Static_Predicates_In_Choices;
 
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