a-stzsup.adb, [...]: Fix warnings for range tests optimized out.

2007-08-14  Robert Dewar  <dewar@adacore.com>
	    Gary Dismukes  <dismukes@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>
	    Thomas Quinot  <quinot@adacore.com>

	* a-stzsup.adb, nlists.adb, lib-util.adb, treepr.adb, 
	a-stwisu.adb, a-strsup.adb: Fix warnings for range
	tests optimized out.

	* exp_ch4.adb (Expand_N_In): Add warnings for range tests optimized out.
	(Get_Allocator_Final_List): For the case of an anonymous access type
	that has a specified Associated_Final_Chain, do not go up to the
	enclosing scope.
	(Expand_N_Type_Conversion): Test for the case of renamings of access
	parameters when deciding whether to apply a run-time accessibility
	check.
	(Convert_Aggr_In_Allocator): Use Insert_Actions to place expanded
	aggregate code before allocator, and ahead of declaration for
	temporary, to prevent access before elaboration when the allocator is
	an actual for an access parameter.
	(Expand_N_Type_Conversion): On an access type conversion involving an
	access parameter, do not apply an accessibility check when the
	operand's original node was an attribute other than 'Access. We now
	create access conversions for the expansion of 'Unchecked_Access and
	'Unrestricted_Access in certain cases and clearly accessibility should
	not be checked for those.

	* exp_ch6.ads, exp_ch6.adb (Add_Call_By_Copy_Code): For an actual that
	includes a type conversion of a packed component that has been expanded,
	recover the original expression for the object, and use this expression
	in the post-call assignment statement, so that the assignment is made
	to the object and not to a back-end temporary.
	(Freeze_Subprogram): In case of primitives of tagged types not defined
	at the library level force generation of code to register the primitive
	in the dispatch table. In addition some code reorganization has been
	done to leave the implementation clear.
	(Expand_Call): When expanding an inherited implicit conversion,
	preserve the type of the inherited function after the intrinsic
	operation has been expanded.

	* exp_ch2.ads, exp_ch2.adb
	(Expand_Entry_Parameter.In_Assignment_Context): An implicit dereference
	of an entry formal appearing in an assignment statement does not assign
	to the formal.
	(Expand_Current_Value): Instead of calling a routine to determine
	whether the prefix of an attribute reference should be optimized or
	not, prevent the optimization of such prefixes all together.

	* lib-xref.adb (Generate_Reference.Is_On_LHS): An indexed or selected
	component whose prefix is known to be of an access type is an implicit
	dereference and does not assign to the prefix.

From-SVN: r127411

gcc/ada/a-strsup.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2003-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 2003-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -783,7 +783,7 @@ package body Ada.Strings.Superbounded is
       Index  : Positive) return Character
    is
    begin
-      if Index in 1 .. Source.Current_Length then
+      if Index <= Source.Current_Length then
          return Source.Data (Index);
       else
          raise Strings.Index_Error;

gcc/ada/a-stwisu.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2003-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 2003-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -784,7 +784,7 @@ package body Ada.Strings.Wide_Superbounded is
       Index  : Positive) return Wide_Character
    is
    begin
-      if Index in 1 .. Source.Current_Length then
+      if Index <= Source.Current_Length then
          return Source.Data (Index);
       else
          raise Strings.Index_Error;

gcc/ada/a-stzsup.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2003-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 2003-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -787,7 +787,7 @@ package body Ada.Strings.Wide_Wide_Superbounded is
       Index  : Positive) return Wide_Wide_Character
    is
    begin
-      if Index in 1 .. Source.Current_Length then
+      if Index <= Source.Current_Length then
          return Source.Data (Index);
       else
          raise Strings.Index_Error;

gcc/ada/exp_ch2.adb

@@ -32,15 +32,16 @@ with Exp_Smem; use Exp_Smem;
 with Exp_Tss;  use Exp_Tss;
 with Exp_Util; use Exp_Util;
 with Exp_VFpt; use Exp_VFpt;
+with Namet;    use Namet;
 with Nmake;    use Nmake;
 with Opt;      use Opt;
 with Sem;      use Sem;
-with Sem_Attr; use Sem_Attr;
 with Sem_Eval; use Sem_Eval;
 with Sem_Res;  use Sem_Res;
 with Sem_Util; use Sem_Util;
 with Sem_Warn; use Sem_Warn;
 with Sinfo;    use Sinfo;
+with Snames;   use Snames;
 with Tbuild;   use Tbuild;
 with Uintp;    use Uintp;
 
@@ -90,13 +91,13 @@ package body Exp_Ch2 is
    procedure Expand_Entry_Parameter (N : Node_Id);
    --  A reference to an entry parameter is modified to be a reference to the
    --  corresponding component of the entry parameter record that is passed by
-   --  the runtime to the accept body procedure
+   --  the runtime to the accept body procedure.
 
    procedure Expand_Formal (N : Node_Id);
    --  A reference to a formal parameter of a protected subprogram is expanded
    --  into the corresponding formal of the unprotected procedure used to
    --  represent the operation within the protected object. In other cases
-   --  Expand_Formal is a noop.
+   --  Expand_Formal is a no-op.
 
    procedure Expand_Protected_Private (N : Node_Id);
    --  A reference to a private component of a protected type is expanded to a
@@ -156,11 +157,18 @@ package body Exp_Ch2 is
 
          and then Nkind (Parent (N)) /= N_Pragma_Argument_Association
 
-         --  Same for attribute references that require a simple name prefix
+         --  Do not replace the prefixes of attribute references, since this
+         --  causes trouble with cases like 4'Size. Also for Name_Asm_Input and
+         --  Name_Asm_Output, don't do replacement anywhere, since we can have
+         --  lvalue references in the arguments.
 
          and then not (Nkind (Parent (N)) = N_Attribute_Reference
-                         and then Requires_Simple_Name_Prefix (
-                                    Attribute_Name (Parent (N))))
+                         and then
+                           (Attribute_Name (Parent (N)) = Name_Asm_Input
+                              or else
+                            Attribute_Name (Parent (N)) = Name_Asm_Output
+                              or else
+                            Prefix (Parent (N)) = N))
 
       then
          --  Case of Current_Value is a compile time known value
@@ -421,6 +429,11 @@ package body Exp_Ch2 is
 
       function In_Assignment_Context (N : Node_Id) return Boolean is
       begin
+         --  Case of use in a call
+
+         --  ??? passing a formal as actual for a mode IN formal is
+         --  considered as an assignment?
+
          if Nkind (Parent (N)) = N_Procedure_Call_Statement
            or else Nkind (Parent (N)) = N_Entry_Call_Statement
            or else
@@ -429,15 +442,25 @@ package body Exp_Ch2 is
          then
             return True;
 
+         --  Case of a parameter association: climb up to enclosing call
+
          elsif Nkind (Parent (N)) = N_Parameter_Association then
             return In_Assignment_Context (Parent (N));
 
+         --  Case of a selected component, indexed component or slice prefix:
+         --  climb up the tree, unless the prefix is of an access type (in
+         --  which case there is an implicit dereference, and the formal itself
+         --  is not being assigned to).
+
          elsif (Nkind (Parent (N)) = N_Selected_Component
                  or else Nkind (Parent (N)) = N_Indexed_Component
                  or else Nkind (Parent (N)) = N_Slice)
+           and then N = Prefix (Parent (N))
+           and then not Is_Access_Type (Etype (N))
            and then In_Assignment_Context (Parent (N))
          then
             return True;
+
          else
             return False;
          end if;
@@ -670,6 +693,8 @@ package body Exp_Ch2 is
    --  through an address clause is rewritten as dereference as well.
 
    function Param_Entity (N : Node_Id) return Entity_Id is
+      Renamed_Obj : Node_Id;
+
    begin
       --  Simple reference case
 
@@ -677,10 +702,22 @@ package body Exp_Ch2 is
          if Is_Formal (Entity (N)) then
             return Entity (N);
 
-         elsif Nkind (Parent (Entity (N))) = N_Object_Renaming_Declaration
-           and then Nkind (Parent (Parent (Entity (N)))) = N_Accept_Statement
-         then
-            return Entity (N);
+         --  Handle renamings of formal parameters and formals of tasks that
+         --  are rewritten as renamings.
+
+         elsif Nkind (Parent (Entity (N))) = N_Object_Renaming_Declaration then
+            Renamed_Obj := Get_Referenced_Object (Renamed_Object (Entity (N)));
+
+            if Is_Entity_Name (Renamed_Obj)
+              and then Is_Formal (Entity (Renamed_Obj))
+            then
+               return Entity (Renamed_Obj);
+
+            elsif
+              Nkind (Parent (Parent (Entity (N)))) = N_Accept_Statement
+            then
+               return Entity (N);
+            end if;
          end if;
 
       else

gcc/ada/exp_ch2.ads

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-1997 Free Software Foundation, Inc.          --
+--          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -37,9 +37,10 @@ package Exp_Ch2 is
    --  Given an expression N, determines if the expression is a reference
    --  to a formal (of a subprogram or entry), and if so returns the Id
    --  of the corresponding formal entity, otherwise returns Empty. The
-   --  reason that this is in Exp_Ch2 is that it has to deal with the
-   --  case where the reference is to an entry formal, and has been
-   --  expanded already. Since Exp_Ch2 is in charge of the expansion, it
-   --  is best suited to knowing how to detect this case.
+   --  reason that this is in Exp_Ch2 is that it has to deal with the case
+   --  where the reference is to an entry formal, and has been expanded
+   --  already. Since Exp_Ch2 is in charge of the expansion, it is best
+   --  suited to knowing how to detect this case. Also handles the case
+   --  of references to renamings of formals.
 
 end Exp_Ch2;

gcc/ada/exp_ch4.adb

@@ -670,7 +670,7 @@ package body Exp_Ch4 is
                   Flist := Get_Allocator_Final_List (N, Base_Type (T), PtrT);
                end if;
 
-               Convert_Aggr_In_Allocator (Tmp_Node, Exp);
+               Convert_Aggr_In_Allocator (N, Tmp_Node, Exp);
             else
                Node := Relocate_Node (N);
                Set_Analyzed (Node);
@@ -741,7 +741,7 @@ package body Exp_Ch4 is
                        Get_Allocator_Final_List (N, Base_Type (T), PtrT);
                   end if;
 
-                  Convert_Aggr_In_Allocator (Tmp_Node, Exp);
+                  Convert_Aggr_In_Allocator (N, Tmp_Node, Exp);
                else
                   Node := Relocate_Node (N);
                   Set_Analyzed (Node);
@@ -935,7 +935,7 @@ package body Exp_Ch4 is
 
          Set_No_Initialization (Expression (Tmp_Node));
          Insert_Action (N, Tmp_Node);
-         Convert_Aggr_In_Allocator (Tmp_Node, Exp);
+         Convert_Aggr_In_Allocator (N, Tmp_Node, Exp);
          Rewrite (N, New_Reference_To (Temp, Loc));
          Analyze_And_Resolve (N, PtrT);
 
@@ -1467,7 +1467,7 @@ package body Exp_Ch4 is
               Make_Implicit_If_Statement (Nod,
                 Condition => Make_Op_Not (Loc, Right_Opnd => Test),
                 Then_Statements => New_List (
-                  Make_Return_Statement (Loc,
+                  Make_Simple_Return_Statement (Loc,
                     Expression => New_Occurrence_Of (Standard_False, Loc))));
          end if;
       end Component_Equality;
@@ -1749,20 +1749,20 @@ package body Exp_Ch4 is
                 Make_Implicit_If_Statement (Nod,
                   Condition => Test_Empty_Arrays,
                   Then_Statements => New_List (
-                    Make_Return_Statement (Loc,
+                    Make_Simple_Return_Statement (Loc,
                       Expression =>
                         New_Occurrence_Of (Standard_True, Loc)))),
 
                 Make_Implicit_If_Statement (Nod,
                   Condition => Test_Lengths_Correspond,
                   Then_Statements => New_List (
-                    Make_Return_Statement (Loc,
+                    Make_Simple_Return_Statement (Loc,
                       Expression =>
                         New_Occurrence_Of (Standard_False, Loc)))),
 
                 Handle_One_Dimension (1, First_Index (Ltyp)),
 
-                Make_Return_Statement (Loc,
+                Make_Simple_Return_Statement (Loc,
                   Expression => New_Occurrence_Of (Standard_True, Loc)))));
 
          Set_Has_Completion (Func_Name, True);
@@ -2590,7 +2590,7 @@ package body Exp_Ch4 is
           Condition       => S_Length_Test (1),
           Then_Statements => New_List (Init_L (1)),
           Elsif_Parts     => Elsif_List,
-          Else_Statements => New_List (Make_Return_Statement (Loc,
+          Else_Statements => New_List (Make_Simple_Return_Statement (Loc,
                                          Expression => S (Nb_Opnds))));
 
       --  Construct the declaration for H
@@ -2641,7 +2641,8 @@ package body Exp_Ch4 is
                       Then_Statements => Copy_Into_R_S (I, I = Nb_Opnds)));
       end loop;
 
-      Append_To (Declare_Stmts, Make_Return_Statement (Loc, Expression => R));
+      Append_To
+        (Declare_Stmts, Make_Simple_Return_Statement (Loc, Expression => R));
 
       --  Construct the declare block
 
@@ -2817,7 +2818,7 @@ package body Exp_Ch4 is
             P := Parent (N);
             while Present (P) loop
                if Nkind (P) = N_Extended_Return_Statement
-                 or else Nkind (P) = N_Return_Statement
+                 or else Nkind (P) = N_Simple_Return_Statement
                then
                   return True;
 
@@ -3441,7 +3442,7 @@ package body Exp_Ch4 is
                --  Postpone the generation of a finalization call for the
                --  current allocator if it acts as a coextension.
 
-               if Is_Coextension (N) then
+               if Is_Dynamic_Coextension (N) then
                   if No (Coextensions (N)) then
                      Set_Coextensions (N, New_Elmt_List);
                   end if;
@@ -3762,24 +3763,42 @@ package body Exp_Ch4 is
             Lo : constant Node_Id := Low_Bound (Rop);
             Hi : constant Node_Id := High_Bound (Rop);
 
+            Ltyp : constant Entity_Id := Etype (Lop);
+
             Lo_Orig : constant Node_Id := Original_Node (Lo);
             Hi_Orig : constant Node_Id := Original_Node (Hi);
 
             Lcheck : constant Compare_Result := Compile_Time_Compare (Lop, Lo);
             Ucheck : constant Compare_Result := Compile_Time_Compare (Lop, Hi);
 
+            Warn1 : constant Boolean :=
+                      Constant_Condition_Warnings
+                        and then Comes_From_Source (N);
+            --  This must be true for any of the optimization warnings, we
+            --  clearly want to give them only for source with the flag on.
+
+            Warn2 : constant Boolean :=
+                      Warn1
+                        and then Nkind (Original_Node (Rop)) = N_Range
+                        and then Is_Integer_Type (Etype (Lo));
+            --  For the case where only one bound warning is elided, we also
+            --  insist on an explicit range and an integer type. The reason is
+            --  that the use of enumeration ranges including an end point is
+            --  common, as is the use of a subtype name, one of whose bounds
+            --  is the same as the type of the expression.
+
          begin
             --  If test is explicit x'first .. x'last, replace by valid check
 
-            if Is_Scalar_Type (Etype (Lop))
+            if Is_Scalar_Type (Ltyp)
               and then Nkind (Lo_Orig) = N_Attribute_Reference
               and then Attribute_Name (Lo_Orig) = Name_First
               and then Nkind (Prefix (Lo_Orig)) in N_Has_Entity
-              and then Entity (Prefix (Lo_Orig)) = Etype (Lop)
+              and then Entity (Prefix (Lo_Orig)) = Ltyp
               and then Nkind (Hi_Orig) = N_Attribute_Reference
               and then Attribute_Name (Hi_Orig) = Name_Last
               and then Nkind (Prefix (Hi_Orig)) in N_Has_Entity
-              and then Entity (Prefix (Hi_Orig)) = Etype (Lop)
+              and then Entity (Prefix (Hi_Orig)) = Ltyp
               and then Comes_From_Source (N)
               and then VM_Target = No_VM
             then
@@ -3787,6 +3806,24 @@ package body Exp_Ch4 is
                return;
             end if;
 
+            --  If bounds of type are known at compile time, and the end points
+            --  are known at compile time and identical, this is another case
+            --  for substituting a valid test. We only do this for discrete
+            --  types, since it won't arise in practice for float types.
+
+            if Comes_From_Source (N)
+              and then Is_Discrete_Type (Ltyp)
+              and then Compile_Time_Known_Value (Type_High_Bound (Ltyp))
+              and then Compile_Time_Known_Value (Type_Low_Bound  (Ltyp))
+              and then Compile_Time_Known_Value (Lo)
+              and then Compile_Time_Known_Value (Hi)
+              and then Expr_Value (Type_High_Bound (Ltyp)) = Expr_Value (Hi)
+              and then Expr_Value (Type_Low_Bound  (Ltyp)) = Expr_Value (Lo)
+            then
+               Substitute_Valid_Check;
+               return;
+            end if;
+
             --  If we have an explicit range, do a bit of optimization based
             --  on range analysis (we may be able to kill one or both checks).
 
@@ -3795,44 +3832,68 @@ package body Exp_Ch4 is
             --  legality checks, because we are constant-folding beyond RM 4.9.
 
             if Lcheck = LT or else Ucheck = GT then
+               if Warn1 then
+                  Error_Msg_N ("?range test optimized away", N);
+                  Error_Msg_N ("\?value is known to be out of range", N);
+               end if;
+
                Rewrite (N,
                  New_Reference_To (Standard_False, Loc));
                Analyze_And_Resolve (N, Rtyp);
                Set_Is_Static_Expression (N, Static);
+
                return;
 
             --  If both checks are known to succeed, replace result
             --  by True, since we know we are in range.
 
             elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then
+               if Warn1 then
+                  Error_Msg_N ("?range test optimized away", N);
+                  Error_Msg_N ("\?value is known to be in range", N);
+               end if;
+
                Rewrite (N,
                  New_Reference_To (Standard_True, Loc));
                Analyze_And_Resolve (N, Rtyp);
                Set_Is_Static_Expression (N, Static);
+
                return;
 
-            --  If lower bound check succeeds and upper bound check is
-            --  not known to succeed or fail, then replace the range check
-            --  with a comparison against the upper bound.
+            --  If lower bound check succeeds and upper bound check is not
+            --  known to succeed or fail, then replace the range check with
+            --  a comparison against the upper bound.
 
             elsif Lcheck in Compare_GE then
+               if Warn2 then
+                  Error_Msg_N ("?lower bound test optimized away", Lo);
+                  Error_Msg_N ("\?value is known to be in range", Lo);
+               end if;
+
                Rewrite (N,
                  Make_Op_Le (Loc,
                    Left_Opnd  => Lop,
                    Right_Opnd => High_Bound (Rop)));
                Analyze_And_Resolve (N, Rtyp);
+
                return;
 
-            --  If upper bound check succeeds and lower bound check is
-            --  not known to succeed or fail, then replace the range check
-            --  with a comparison against the lower bound.
+            --  If upper bound check succeeds and lower bound check is not
+            --  known to succeed or fail, then replace the range check with
+            --  a comparison against the lower bound.
 
             elsif Ucheck in Compare_LE then
+               if Warn2 then
+                  Error_Msg_N ("?upper bound test optimized away", Hi);
+                  Error_Msg_N ("\?value is known to be in range", Hi);
+               end if;
+
                Rewrite (N,
                  Make_Op_Ge (Loc,
                    Left_Opnd  => Lop,
                    Right_Opnd => Low_Bound (Rop)));
                Analyze_And_Resolve (N, Rtyp);
+
                return;
             end if;
          end;
@@ -4203,9 +4264,9 @@ package body Exp_Ch4 is
           Right_Opnd =>
             Make_In (Loc,
               Left_Opnd  => Left_Opnd (N),
-                     Right_Opnd => Right_Opnd (N))));
+              Right_Opnd => Right_Opnd (N))));
 
-      --  We want this tp appear as coming from source if original does (see
+      --  We want this to appear as coming from source if original does (see
       --  tranformations in Expand_N_In).
 
       Set_Comes_From_Source (N, Cfs);
@@ -6295,7 +6356,7 @@ package body Exp_Ch4 is
             Make_Handled_Sequence_Of_Statements (Loc,
               Statements => New_List (
                 Loop_Statement,
-                Make_Return_Statement (Loc,
+                Make_Simple_Return_Statement (Loc,
                   Expression =>
                     Make_Identifier (Loc, Chars (B)))))));
 
@@ -7413,13 +7474,23 @@ package body Exp_Ch4 is
 
       if Is_Access_Type (Target_Type) then
 
-         --  Apply an accessibility check if the operand is an
-         --  access parameter. Note that other checks may still
-         --  need to be applied below (such as tagged type checks).
+         --  Apply an accessibility check when the conversion operand is an
+         --  access parameter (or a renaming thereof), unless conversion was
+         --  expanded from an unchecked or unrestricted access attribute. Note
+         --  that other checks may still need to be applied below (such as
+         --  tagged type checks).
 
          if Is_Entity_Name (Operand)
-           and then Ekind (Entity (Operand)) in Formal_Kind
+           and then
+             (Is_Formal (Entity (Operand))
+               or else
+                 (Present (Renamed_Object (Entity (Operand)))
+                   and then Is_Entity_Name (Renamed_Object (Entity (Operand)))
+                   and then Is_Formal
+                              (Entity (Renamed_Object (Entity (Operand))))))
            and then Ekind (Etype (Operand)) = E_Anonymous_Access_Type
+           and then (Nkind (Original_Node (N)) /= N_Attribute_Reference
+                      or else Attribute_Name (Original_Node (N)) = Name_Access)
          then
             Apply_Accessibility_Check (Operand, Target_Type);
 
@@ -8172,9 +8243,12 @@ package body Exp_Ch4 is
 
          --  Case of an access discriminant, or (Ada 2005), of an anonymous
          --  access component or anonymous access function result: find the
-         --  final list associated with the scope of the type.
+         --  final list associated with the scope of the type. (In the
+         --  anonymous access component kind, a list controller will have
+         --  been allocated when freezing the record type, and PtrT has an
+         --  Associated_Final_Chain attribute designating it.)
 
-         else
+         elsif No (Associated_Final_Chain (PtrT)) then
             Owner := Scope (PtrT);
          end if;
       end if;
@@ -8480,7 +8554,7 @@ package body Exp_Ch4 is
           Then_Statements => New_List (Inner_If),
 
           Else_Statements => New_List (
-            Make_Return_Statement (Loc,
+            Make_Simple_Return_Statement (Loc,
               Expression =>
                 Make_Op_Gt (Loc,
                   Left_Opnd =>
@@ -8551,7 +8625,7 @@ package body Exp_Ch4 is
 
           Then_Statements =>
             New_List (
-              Make_Return_Statement (Loc,
+              Make_Simple_Return_Statement (Loc,
                 Expression => New_Reference_To (Standard_False, Loc))),
 
           Elsif_Parts => New_List (
@@ -8567,12 +8641,12 @@ package body Exp_Ch4 is
 
               Then_Statements =>
                 New_List (
-                  Make_Return_Statement (Loc,
+                  Make_Simple_Return_Statement (Loc,
                      Expression => New_Reference_To (Standard_True, Loc))))),
 
           Else_Statements => New_List (
             Loop_Statement,
-            Make_Return_Statement (Loc,
+            Make_Simple_Return_Statement (Loc,
               Expression => Final_Expr)));
 
       --  (X : a; Y: a)
@@ -8741,7 +8815,7 @@ package body Exp_Ch4 is
             Make_Handled_Sequence_Of_Statements (Loc,
               Statements => New_List (
                 Loop_Statement,
-                Make_Return_Statement (Loc,
+                Make_Simple_Return_Statement (Loc,
                   Expression => New_Reference_To (C, Loc)))));
 
       return Func_Body;

gcc/ada/exp_ch6.adb

@@ -1123,13 +1123,48 @@ package body Exp_Ch6 is
             Rewrite (Actual, New_Reference_To (Temp, Loc));
             Analyze (Actual);
 
-            Append_To (Post_Call,
-              Make_Assignment_Statement (Loc,
-                Name       => New_Occurrence_Of (Var, Loc),
-                Expression => Expr));
+            --  If the actual is a conversion of a packed reference, it may
+            --  already have been expanded by Remove_Side_Effects, and the
+            --  resulting variable is a temporary which does not designate
+            --  the proper out-parameter, which may not be addressable. In
+            --  that case, generate an assignment to the original expression
+            --  (before expansion of the  packed reference) so that the proper
+            --  expansion of assignment to a packed component can take place.
 
-            Set_Assignment_OK (Name (Last (Post_Call)));
+            declare
+               Obj : Node_Id;
+               Lhs : Node_Id;
+
+            begin
+               if Is_Renaming_Of_Object (Var)
+                 and then Nkind (Renamed_Object (Var)) = N_Selected_Component
+                 and then Is_Entity_Name (Prefix (Renamed_Object (Var)))
+                 and then Nkind (Original_Node (Prefix (Renamed_Object (Var))))
+                   = N_Indexed_Component
+                 and then
+                   Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var))))
+               then
+                  Obj := Renamed_Object (Var);
+                  Lhs :=
+                    Make_Selected_Component (Loc,
+                      Prefix        =>
+                        New_Copy_Tree (Original_Node (Prefix (Obj))),
+                      Selector_Name => New_Copy (Selector_Name (Obj)));
+                  Reset_Analyzed_Flags (Lhs);
+
+               else
+                  Lhs :=  New_Occurrence_Of (Var, Loc);
+               end if;
+
+               Set_Assignment_OK (Lhs);
+
+               Append_To (Post_Call,
+                 Make_Assignment_Statement (Loc,
+                   Name       => Lhs,
+                   Expression => Expr));
+            end;
          end if;
+
       end Add_Call_By_Copy_Code;
 
       ----------------------------------
@@ -2104,13 +2139,21 @@ package body Exp_Ch6 is
 
             if Is_Entity_Name (Prev_Orig) then
 
-               --  When passing an access parameter as the actual to another
-               --  access parameter we need to pass along the actual's own
-               --  associated access level parameter. This is done if we are
-               --  in the scope of the formal access parameter (if this is an
-               --  inlined body the extra formal is irrelevant).
-
-               if Ekind (Entity (Prev_Orig)) in Formal_Kind
+               --  When passing an access parameter, or a renaming of an access
+               --  parameter, as the actual to another access parameter we need
+               --  to pass along the actual's own access level parameter. This
+               --  is done if we are within the scope of the formal access
+               --  parameter (if this is an inlined body the extra formal is
+               --  irrelevant).
+
+               if (Is_Formal (Entity (Prev_Orig))
+                    or else
+                      (Present (Renamed_Object (Entity (Prev_Orig)))
+                        and then
+                          Is_Entity_Name (Renamed_Object (Entity (Prev_Orig)))
+                        and then
+                          Is_Formal
+                            (Entity (Renamed_Object (Entity (Prev_Orig))))))
                  and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type
                  and then In_Open_Scopes (Scope (Entity (Prev_Orig)))
                then
@@ -2218,7 +2261,7 @@ package body Exp_Ch6 is
             if Is_Access_Type (Etype (Formal))
               and then Can_Never_Be_Null (Etype (Formal))
               and then Nkind (Prev) /= N_Raise_Constraint_Error
-              and then (Nkind (Prev) = N_Null
+              and then (Known_Null (Prev)
                           or else not Can_Never_Be_Null (Etype (Prev)))
             then
                Install_Null_Excluding_Check (Prev);
@@ -2410,7 +2453,7 @@ package body Exp_Ch6 is
                   then
                      Error_Msg_NE
                        ("tag-indeterminate expression "
-                         & " must have designated type& ('R'M 5.2 (6))",
+                         & " must have designated type& (RM 5.2 (6))",
                            N, Root_Type (Etype (Name (Ass))));
                   else
                      Propagate_Tag (Name (Ass), N);
@@ -2419,7 +2462,7 @@ package body Exp_Ch6 is
                elsif Etype (N) /= Root_Type (Etype (Name (Ass))) then
                   Error_Msg_NE
                     ("tag-indeterminate expression must have type&"
-                     & "('R'M 5.2 (6))", N, Root_Type (Etype (Name (Ass))));
+                     & "(RM 5.2 (6))", N, Root_Type (Etype (Name (Ass))));
 
                else
                   Propagate_Tag (Name (Ass), N);
@@ -2708,9 +2751,21 @@ package body Exp_Ch6 is
       --  In the case where the intrinsic is to be processed by the back end,
       --  the call to Expand_Intrinsic_Call will do nothing, which is fine,
       --  since the idea in this case is to pass the call unchanged.
+      --  If the intrinsic is an inherited unchecked conversion, and the
+      --  derived type is the target type of the conversion, we must retain
+      --  it as the return type of the expression. Otherwise the expansion
+      --  below, which uses the parent operation, will yield the wrong type.
 
       if Is_Intrinsic_Subprogram (Subp) then
          Expand_Intrinsic_Call (N, Subp);
+
+         if Nkind (N) = N_Unchecked_Type_Conversion
+           and then Parent_Subp /= Orig_Subp
+           and then Etype (Parent_Subp) /= Etype (Orig_Subp)
+         then
+            Set_Etype (N, Etype (Orig_Subp));
+         end if;
+
          return;
       end if;
 
@@ -3147,7 +3202,7 @@ package body Exp_Ch6 is
                    and then
                      (No (Stat2)
                        or else
-                         (Nkind (Stat2) = N_Return_Statement
+                         (Nkind (Stat2) = N_Simple_Return_Statement
                            and then No (Next (Stat2))));
             end;
          end if;
@@ -3211,19 +3266,21 @@ package body Exp_Ch6 is
                   Rewrite (N, New_Occurrence_Of (A, Loc));
                   Check_Private_View (N);
 
-               else   --  numeric literal
+               --  Numeric literal
+
+               else
                   Rewrite (N, New_Copy (A));
                end if;
             end if;
 
             return Skip;
 
-         elsif Nkind (N) = N_Return_Statement then
-
+         elsif Nkind (N) = N_Simple_Return_Statement then
             if No (Expression (N)) then
                Make_Exit_Label;
-               Rewrite (N, Make_Goto_Statement (Loc,
-                 Name => New_Copy (Lab_Id)));
+               Rewrite (N,
+                 Make_Goto_Statement (Loc,
+                   Name => New_Copy (Lab_Id)));
 
             else
                if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements
@@ -3863,7 +3920,7 @@ package body Exp_Ch6 is
          if Is_Inherently_Limited_Type (Typ) then
             return True;
 
-         elsif Nkind (Parent (N)) /= N_Return_Statement then
+         elsif Nkind (Parent (N)) /= N_Simple_Return_Statement then
             return False;
 
          elsif Requires_Transient_Scope (Typ) then
@@ -4113,7 +4170,7 @@ package body Exp_Ch6 is
                Loc := Sloc (Last_Stm);
             end if;
 
-            Append_To (S, Make_Return_Statement (Loc));
+            Append_To (S, Make_Simple_Return_Statement (Loc));
          end if;
       end Add_Return;
 
@@ -4275,7 +4332,8 @@ package body Exp_Ch6 is
       then
          Add_Discriminal_Declarations
            (Declarations (N), Scop, Name_uObject, Loc);
-         Add_Private_Declarations (Declarations (N), Scop, Name_uObject, Loc);
+         Add_Private_Declarations
+           (Declarations (N), Scop, Name_uObject, Loc);
 
          --  Associate privals and discriminals with the next protected
          --  operation body to be expanded. These are used to expand references
@@ -4787,7 +4845,7 @@ package body Exp_Ch6 is
 
    function Is_Build_In_Place_Function_Return (N : Node_Id) return Boolean is
    begin
-      if Nkind (N) = N_Return_Statement
+      if Nkind (N) = N_Simple_Return_Statement
         or else Nkind (N) = N_Extended_Return_Statement
       then
          return Is_Build_In_Place_Function
@@ -4841,11 +4899,7 @@ package body Exp_Ch6 is
          while Present (Iface_DT_Ptr)
             and then Ekind (Node (Iface_DT_Ptr)) = E_Constant
          loop
-            Expand_Interface_Thunk
-              (N           => Prim,
-               Thunk_Alias => Prim,
-               Thunk_Id    => Thunk_Id,
-               Thunk_Code  => Thunk_Code);
+            Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code);
 
             if Present (Thunk_Code) then
                Insert_Actions (N, New_List (
@@ -4867,89 +4921,88 @@ package body Exp_Ch6 is
       --  Local variables
 
       Subp : constant Entity_Id := Entity (N);
-      Typ  : constant Entity_Id := Etype (Subp);
-      Utyp : constant Entity_Id := Underlying_Type (Typ);
 
    begin
-      if not Static_Dispatch_Tables then
+      --  We suppress the initialization of the dispatch table entry when
+      --  VM_Target because the dispatching mechanism is handled internally
+      --  by the VM.
+
+      if Is_Dispatching_Operation (Subp)
+        and then not Is_Abstract_Subprogram (Subp)
+        and then Present (DTC_Entity (Subp))
+        and then Present (Scope (DTC_Entity (Subp)))
+        and then VM_Target = No_VM
+        and then not Restriction_Active (No_Dispatching_Calls)
+        and then RTE_Available (RE_Tag)
+      then
          declare
-            E   : constant Entity_Id := Subp;
-            Typ : Entity_Id;
+            Typ : constant Entity_Id := Scope (DTC_Entity (Subp));
 
          begin
-            --  We assume that imported CPP primitives correspond with objects
-            --  whose constructor is in the CPP side (and therefore we don't
-            --  need to generate code to register them in the dispatch table).
+            --  Handle private overriden primitives
 
-            if Is_Imported (E)
-              and then Convention (E) = Convention_CPP
-            then
-               return;
+            if not Is_CPP_Class (Typ) then
+               Check_Overriding_Operation (Subp);
             end if;
 
-            --  When a primitive is frozen, enter its name in the corresponding
-            --  dispatch table. If the DTC_Entity field is not set this is
-            --  an overridden primitive that can be ignored. We suppress the
-            --  initialization of the dispatch table entry when VM_Target
-            --  because the dispatching mechanism is handled internally by
-            --  the VM.
-
-            if Is_Dispatching_Operation (E)
-              and then not Is_Abstract_Subprogram (E)
-              and then Present (DTC_Entity (E))
-              and then VM_Target = No_VM
-              and then not Is_CPP_Class (Scope (DTC_Entity (E)))
-            then
-               Check_Overriding_Operation (E);
+            --  We assume that imported CPP primitives correspond with objects
+            --  whose constructor is in the CPP side; therefore we don't need
+            --  to generate code to register them in the dispatch table.
 
-               --  Register the primitive in its dispatch table if we are not
-               --  compiling under No_Dispatching_Calls restriction
+            if Is_CPP_Class (Typ) then
+               null;
 
-               if not Restriction_Active (No_Dispatching_Calls)
-                 and then RTE_Available (RE_Tag)
-               then
-                  Typ := Scope (DTC_Entity (E));
+            --  Handle CPP primitives found in derivations of CPP_Class types.
+            --  These primitives must have been inherited from some parent, and
+            --  there is no need to register them in the dispatch table because
+            --  Build_Inherit_Prims takes care of the initialization of these
+            --  slots.
 
-                  if not Is_Interface (Typ)
-                    or else Present (Abstract_Interface_Alias (E))
-                  then
-                     if Is_Predefined_Dispatching_Operation (E) then
-                        Register_Predefined_DT_Entry (E);
-                     end if;
+            elsif Is_Imported (Subp)
+                    and then (Convention (Subp) = Convention_CPP
+                                or else Convention (Subp) = Convention_C)
+            then
+               null;
+
+            --  Generate code to register the primitive in non statically
+            --  allocated dispatch tables
+
+            elsif not Static_Dispatch_Tables
+              or else not
+                Is_Library_Level_Tagged_Type (Scope (DTC_Entity (Subp)))
+            then
+               --  When a primitive is frozen, enter its name in its dispatch
+               --  table slot.
 
-                     Register_Primitive (Loc,
-                       Prim    => E,
-                       Ins_Nod => N);
+               if not Is_Interface (Typ)
+                 or else Present (Abstract_Interface_Alias (Subp))
+               then
+                  if Is_Predefined_Dispatching_Operation (Subp) then
+                     Register_Predefined_DT_Entry (Subp);
                   end if;
+
+                  Register_Primitive (Loc,
+                    Prim    => Subp,
+                    Ins_Nod => N);
                end if;
             end if;
          end;
-
-      --  GCC 4.1 backend
-
-      else
-         --  Handle private overriden primitives
-
-         if Is_Dispatching_Operation (Subp)
-           and then not Is_Abstract_Subprogram (Subp)
-           and then Present (DTC_Entity (Subp))
-           and then VM_Target = No_VM
-           and then not Is_CPP_Class (Scope (DTC_Entity (Subp)))
-         then
-            Check_Overriding_Operation (Subp);
-         end if;
       end if;
 
       --  Mark functions that return by reference. Note that it cannot be part
       --  of the normal semantic analysis of the spec since the underlying
       --  returned type may not be known yet (for private types).
 
-      if Is_Inherently_Limited_Type (Typ) then
-         Set_Returns_By_Ref (Subp);
-
-      elsif Present (Utyp) and then CW_Or_Controlled_Type (Utyp) then
-         Set_Returns_By_Ref (Subp);
-      end if;
+      declare
+         Typ  : constant Entity_Id := Etype (Subp);
+         Utyp : constant Entity_Id := Underlying_Type (Typ);
+      begin
+         if Is_Inherently_Limited_Type (Typ) then
+            Set_Returns_By_Ref (Subp);
+         elsif Present (Utyp) and then CW_Or_Controlled_Type (Utyp) then
+            Set_Returns_By_Ref (Subp);
+         end if;
+      end;
    end Freeze_Subprogram;
 
    -------------------------------------------

gcc/ada/exp_ch6.ads

@@ -72,7 +72,7 @@ package Exp_Ch6 is
       --  Present if result type contains tasks. Master associated with
       --  calling context.
       BIP_Activation_Chain,
-      --  Present if result type contains tasks. Caller's activation chain.
+      --  Present if result type contains tasks. Caller's activation chain
       BIP_Object_Access);
       --  Present for all build-in-place functions. Address at which to place
       --  the return object, or null if BIP_Alloc_Form indicates
@@ -114,9 +114,9 @@ package Exp_Ch6 is
    --  expression applied to such a call; otherwise returns False.
 
    function Is_Build_In_Place_Function_Return (N : Node_Id) return Boolean;
-   --  Ada 2005 (AI-318-02): Returns True if N is an N_Return_Statement or
-   --  N_Extended_Return_Statement and it applies to a build-in-place function
-   --  or generic function.
+   --  Ada 2005 (AI-318-02): Returns True if N is an N_Simple_Return_Statement
+   --  or N_Extended_Return_Statement and it applies to a build-in-place
+   --  function or generic function.
 
    procedure Make_Build_In_Place_Call_In_Allocator
      (Allocator     : Node_Id;

gcc/ada/lib-util.adb

@@ -74,13 +74,19 @@ package body Lib.Util is
    --  Start of processing for Write_Info_Char_Code
 
    begin
-      if Code in 16#00# .. 16#7F# then
+      --  00 .. 7F
+
+      if Code <= 16#7F# then
          Write_Info_Char (Character'Val (Code));
 
-      elsif Code in 16#80# .. 16#FF# then
+      --  80 .. FF
+
+      elsif Code <= 16#FF# then
          Write_Info_Char ('U');
          Write_Info_Hex_Byte (Natural (Code));
 
+      --  0100 .. FFFF
+
       else
          Write_Info_Char ('W');
          Write_Info_Hex_Byte (Natural (Code / 256));

gcc/ada/lib-xref.adb

@@ -223,13 +223,20 @@ package body Lib.Xref is
       --   Prefix    Of an indexed or selected component that is present in a
       --             subtree rooted by an assignment statement. There is no
       --             restriction of nesting of components, thus cases such as
-      --             A.B(C).D are handled properly.
+      --             A.B (C).D are handled properly.
+      --             However a prefix of a dereference (either implicit or
+      --             explicit) is never considered as on a LHS.
 
       ---------------
       -- Is_On_LHS --
       ---------------
 
-      --  Couldn't we use Is_Lvalue or whatever it is called ???
+      --  ??? There are several routines here and there that perform a similar
+      --      (but subtly different) computation, which should be factored:
+
+      --      Sem_Util.May_Be_Lvalue
+      --      Sem_Util.Known_To_Be_Assigned
+      --      Exp_Ch2.Expand_Entry_Parameter.In_Assignment_Context
 
       function Is_On_LHS (Node : Node_Id) return Boolean is
          N : Node_Id := Node;
@@ -247,13 +254,28 @@ package body Lib.Xref is
 
          while Nkind (Parent (N)) /= N_Assignment_Statement loop
 
-            --  Check whether the parent is a component and the
-            --  current node is its prefix.
+            --  Check whether the parent is a component and the current node
+            --  is its prefix, but return False if the current node has an
+            --  access type, as in that case the selected or indexed component
+            --  is an implicit dereference, and the LHS is the designated
+            --  object, not the access object.
+
+            --  ??? case of a slice assignment?
+
+            --  ??? Note that in some cases this is called too early
+            --  (see comments in Sem_Ch8.Find_Direct_Name), at a point where
+            --  the tree is not fully typed yet. In that case we may lack
+            --  an Etype for N, and we must disable the check for an implicit
+            --  dereference. If the dereference is on an LHS, this causes a
+            --  false positive.
 
             if (Nkind (Parent (N)) = N_Selected_Component
                   or else
                 Nkind (Parent (N)) = N_Indexed_Component)
               and then Prefix (Parent (N)) = N
+              and then not (Present (Etype (N))
+                              and then
+                            Is_Access_Type (Etype (N)))
             then
                N := Parent (N);
             else
@@ -370,7 +392,7 @@ package body Lib.Xref is
          --  a left hand side. We also set the Referenced_As_LHS flag of a
          --  prefix of selected or indexed component.
 
-         if Ekind (E) = E_Variable
+         if (Ekind (E) = E_Variable or else Is_Formal (E))
            and then Is_On_LHS (N)
          then
             Set_Referenced_As_LHS (E);
@@ -1004,9 +1026,8 @@ package body Lib.Xref is
                end if;
             end if;
 
-            --  Collect inherited primitive operations that may be
-            --  declared in another unit and have no visible reference
-            --  in the current one.
+            --  Collect inherited primitive operations that may be declared in
+            --  another unit and have no visible reference in the current one.
 
             if Is_Type (Ent)
               and then Is_Tagged_Type (Ent)

gcc/ada/nlists.adb

@@ -304,7 +304,7 @@ package body Nlists is
       if List = No_List then
          return Empty;
       else
-         pragma Assert (List in First_List_Id .. Lists.Last);
+         pragma Assert (List <= Lists.Last);
          return Lists.Table (List).First;
       end if;
    end First;
@@ -630,7 +630,7 @@ package body Nlists is
 
    function Last (List : List_Id) return Node_Id is
    begin
-      pragma Assert (List in First_List_Id .. Lists.Last);
+      pragma Assert (List <= Lists.Last);
       return Lists.Table (List).Last;
    end Last;
 
@@ -1028,7 +1028,7 @@ package body Nlists is
 
    function Parent (List : List_Id) return Node_Id is
    begin
-      pragma Assert (List in First_List_Id .. Lists.Last);
+      pragma Assert (List <= Lists.Last);
       return Lists.Table (List).Parent;
    end Parent;
 
@@ -1355,7 +1355,7 @@ package body Nlists is
 
    procedure Set_Parent (List : List_Id; Node : Node_Id) is
    begin
-      pragma Assert (List in First_List_Id .. Lists.Last);
+      pragma Assert (List <= Lists.Last);
       Lists.Table (List).Parent := Node;
    end Set_Parent;
 

gcc/ada/treepr.adb

@@ -796,8 +796,7 @@ package body Treepr is
 
       Notes := False;
 
-      if N not in
-        Atree_Private_Part.Nodes.First .. Atree_Private_Part.Nodes.Last then
+      if N > Atree_Private_Part.Nodes.Last then
          Print_Str (" (no such node)");
          Print_Eol;
          return;