[Ada] Add Return_Statement field

[Pierre-Marie de Rodat]

Used by GNAT LLVM to handle E_Constant and E_Variable with
Is_Return_Object.

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

gcc/ada/

        * einfo.ads (Return_Statement): Add documentation.
        * exp_ch6.adb (Expand_N_Extended_Return_Statement): Set it.
        * gen_il-fields.ads: Add it.
        * gen_il-gen-gen_entities.adb: Add it.
diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -4206,6 +4206,11 @@ package Einfo is
 --       entities (for convenience in setting it), but is only tested
 --       for the function case.
 
+--    Return_Statement
+--       Defined in E_Variable. Set when Is_Return_Object is set, in which
+--       case it points to the N_Simple_Return_Statement made from the
+--       extended return statement.
+
 --    Returns_By_Ref
 --       Defined in subprogram type entities and functions. Set if a function
 --       (or an access-to-function type) returns a result by reference, either


diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -6033,6 +6033,7 @@ package body Exp_Ch6 is
       --  Set the flag to prevent infinite recursion
 
       Set_Comes_From_Extended_Return_Statement (Return_Stmt);
+      Set_Return_Statement (Ret_Obj_Id, Return_Stmt);
 
       Rewrite (N, Result);
 


diff --git a/gcc/ada/gen_il-fields.ads b/gcc/ada/gen_il-fields.ads
--- a/gcc/ada/gen_il-fields.ads
+++ b/gcc/ada/gen_il-fields.ads
@@ -874,6 +874,7 @@ package Gen_IL.Fields is
       Requires_Overriding,
       Return_Applies_To,
       Return_Present,
+      Return_Statement,
       Returns_By_Ref,
       Reverse_Bit_Order,
       Reverse_Storage_Order,


diff --git a/gcc/ada/gen_il-gen-gen_entities.adb b/gcc/ada/gen_il-gen-gen_entities.adb
--- a/gcc/ada/gen_il-gen-gen_entities.adb
+++ b/gcc/ada/gen_il-gen-gen_entities.adb
@@ -350,6 +350,7 @@ begin -- Gen_IL.Gen.Gen_Entities
         Sm (Prival_Link, Node_Id),
         Sm (Related_Expression, Node_Id),
         Sm (Related_Type, Node_Id),
+        Sm (Return_Statement, Node_Id),
         Sm (Size_Check_Code, Node_Id),
         Sm (SPARK_Pragma, Node_Id),
         Sm (SPARK_Pragma_Inherited, Flag),
@@ -421,6 +422,7 @@ begin -- Gen_IL.Gen.Gen_Entities
         Sm (Prival_Link, Node_Id),
         Sm (Related_Expression, Node_Id),
         Sm (Related_Type, Node_Id),
+        Sm (Return_Statement, Node_Id),
         Sm (Shared_Var_Procs_Instance, Node_Id),
         Sm (Size_Check_Code, Node_Id),
         Sm (SPARK_Pragma, Node_Id),