[Ada] Fix handling of 'Enum_Rep and renamings

Message ID 20200608080043.GA90415@adacore.com
State New
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Series
  • [Ada] Fix handling of 'Enum_Rep and renamings
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Commit Message

Pierre-Marie de Rodat June 8, 2020, 8 a.m.
Most cases were actually handled fine thanks to some special handling in
exp_attr.adb, but cases of e.g. a renaming of renaming were not handled
properly. Taking this opportunity to simplify the code and remove
special cases by actually adding support for 'Enum_Rep directly in
Eval_Type_Conversion.

Tested on x86_64-pc-linux-gnu, committed on trunk

2020-06-08  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* sem_eval.adb (Eval_Type_Conversion): Fix handling of
	enumeration to integer conversions.
	* exp_attr.adb (Expand_N_Attribute_Reference
	[Attribute_Enum_Rep]): Remove special casing for first-level
	renaming, best left to the general folding mechanism via
	Eval_Type_Conversion.

Patch

--- gcc/ada/exp_attr.adb
+++ gcc/ada/exp_attr.adb
@@ -3168,21 +3168,6 @@  package body Exp_Attr is
             Rewrite (N,
               Make_Integer_Literal (Loc, Enumeration_Rep (Entity (Expr))));
 
-         --  If this is a renaming of a literal, recover the representation
-         --  of the original. If it renames an expression there is nothing to
-         --  fold.
-
-         elsif Nkind (Expr) in N_Has_Entity
-           and then Ekind (Entity (Expr)) = E_Constant
-           and then Present (Renamed_Object (Entity (Expr)))
-           and then Is_Entity_Name (Renamed_Object (Entity (Expr)))
-           and then Ekind (Entity (Renamed_Object (Entity (Expr)))) =
-                      E_Enumeration_Literal
-         then
-            Rewrite (N,
-              Make_Integer_Literal (Loc,
-                Enumeration_Rep (Entity (Renamed_Object (Entity (Expr))))));
-
          --  If not constant-folded above, Enum_Type'Enum_Rep (X) or
          --  X'Enum_Rep expands to
 

--- gcc/ada/sem_eval.adb
+++ gcc/ada/sem_eval.adb
@@ -4031,8 +4031,13 @@  package body Sem_Eval is
 
             --  Real to integer conversion
 
-            else
+            elsif To_Be_Treated_As_Real (Source_Type) then
                Result := UR_To_Uint (Expr_Value_R (Operand));
+
+            --  Enumeration to integer conversion, aka 'Enum_Rep
+
+            else
+               Result := Expr_Rep_Value (Operand);
             end if;
 
             --  If fixed-point type (Conversion_OK must be set), then the
@@ -4076,7 +4081,6 @@  package body Sem_Eval is
       if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
          Out_Of_Range (N);
       end if;
-
    end Eval_Type_Conversion;
 
    -------------------