This changes the way some assignments of aggregates of dynamic
discriminated record types are expanded by the front-end: they used to
always give rise to the creation of a temporary, which is unnecessary if
the by-copy semantics can be guaranteed.
This also puts the treatment of qualified aggregates on par with that of
unqualified aggregates in other cases.
No functional changes.
Tested on x86_64-pc-linux-gnu, committed on trunk
2020-06-10 Eric Botcazou <ebotca...@adacore.com>
gcc/ada/
* exp_aggr.adb (In_Place_Assign_OK): Do not necessarily return
false for a type with discriminants.
(Convert_To_Assignments): Use Parent_Node and Parent_Kind more
consistently. In the in-place assignment case, first apply a
discriminant check if need be, and be prepared for a rewritten
aggregate as a result.--- gcc/ada/exp_aggr.adb
+++ gcc/ada/exp_aggr.adb
@@ -4283,12 +4283,9 @@ package body Exp_Aggr is
-- Start of processing for In_Place_Assign_OK
begin
- -- By-copy semantic cannot be guaranteed for controlled objects or
- -- objects with discriminants.
+ -- By-copy semantic cannot be guaranteed for controlled objects
- if Needs_Finalization (Etype (N))
- or else Has_Discriminants (Etype (N))
- then
+ if Needs_Finalization (Etype (N)) then
return False;
elsif Is_Array and then Present (Component_Associations (N)) then
@@ -4465,26 +4462,40 @@ package body Exp_Aggr is
-- assignment.
if Is_Limited_Type (Typ)
- and then Nkind (Parent (N)) = N_Assignment_Statement
+ and then Parent_Kind = N_Assignment_Statement
then
- Target_Expr := New_Copy_Tree (Name (Parent (N)));
- Insert_Actions (Parent (N),
+ Target_Expr := New_Copy_Tree (Name (Parent_Node));
+ Insert_Actions (Parent_Node,
Build_Record_Aggr_Code (N, Typ, Target_Expr));
- Rewrite (Parent (N), Make_Null_Statement (Loc));
+ Rewrite (Parent_Node, Make_Null_Statement (Loc));
-- Do not declare a temporary to initialize an aggregate assigned to an
-- identifier when in-place assignment is possible, preserving the
-- by-copy semantic of aggregates. This avoids large stack usage and
-- generates more efficient code.
- elsif Nkind (Parent (N)) = N_Assignment_Statement
- and then Nkind (Name (Parent (N))) = N_Identifier
+ elsif Parent_Kind = N_Assignment_Statement
+ and then Nkind (Name (Parent_Node)) = N_Identifier
and then In_Place_Assign_OK (N)
then
- Target_Expr := New_Copy_Tree (Name (Parent (N)));
- Insert_Actions (Parent (N),
- Build_Record_Aggr_Code (N, Typ, Target_Expr));
- Rewrite (Parent (N), Make_Null_Statement (Loc));
+ declare
+ Lhs : constant Node_Id := Name (Parent_Node);
+ begin
+ -- Apply discriminant check if required
+
+ if Has_Discriminants (Etype (N)) then
+ Apply_Discriminant_Check (N, Etype (Lhs), Lhs);
+ end if;
+
+ -- The check just above may have replaced the aggregate with a CE
+
+ if Nkind_In (N, N_Aggregate, N_Extension_Aggregate) then
+ Target_Expr := New_Copy_Tree (Lhs);
+ Insert_Actions (Parent_Node,
+ Build_Record_Aggr_Code (N, Typ, Target_Expr));
+ Rewrite (Parent_Node, Make_Null_Statement (Loc));
+ end if;
+ end;
else
Temp := Make_Temporary (Loc, 'A', N);
