Re: Add VIEW_CONVERT_EXPR to operand_equal_p

[Eric Botcazou <ebotcazou at adacore dot com>]

> I wasn't aware that x86/IA-64 is still broken.  I am flying to NY tomorrow
> but will try to take a look. The ICEs are not caused by operand_equal_p
> changes, but the change to useless_type_conversion to ignore mode on
> aggregate types.

Sure, but I'd like to avoid hiding new problems against preexisting ICEs.

> A safe way would be to add the mode check back (as was in my original patch)
> that does not change my original intent to separate CANONICAL_TYPE from
> gimple semantic type equivalence machinery. It was however outcome of the
> discussion that we would preffer the mode to be ignored in this case which
> means fixing expansion side.

What do we gain by doing this?  Pretending that the mode doesn't matter is a 
lie at the RTL level and I don't see why GIMPLE would have to care.

> I have no way to reproduce the IA-64 change, but will send proposed patch -
> from backtrace it was clear where the wrong mode went in.  Will wait with
> operand_euqal_p changess until this is fixed.

Thanks.  I have installed 2 testcases that exhibit 2 distinct ICEs on x86-64, 
pack21.adb at -O0 and pack22.adb at -O1 (similar to the IA-64 one).


	PR middle-end/67966
	* gnat.dg/pack21.adb: New test.
	* gnat.dg/pack22.adb: Likewise.
	* gnat.dg/pack22_pkg.ad[sb]: New helper.


-- 
Eric Botcazou

-- { dg-do compile }
-- { dg-options "-gnatws" }

procedure Pack21 is

  type Enum is (ZERO, ONE, TWO, THREE, FOUR, FIVE, SIX,
                SEVEN, EIGHT, NINE, TEN, ELEVEN, TWELVE,
                THIRTEEN, FOURTEEN, FIFTEEN);

  type Rec1 is record
    I1 : INTEGER range 0 .. 800;
    I2 : INTEGER range 0 .. 15 := 0;
    E  : Enum;
  end record;
  pragma PACK (Rec1);

  type Rec2 is record
    F : Rec1;
  end record;

  for Rec2 use record
    F at 0 range 2 .. 19;
  end record;

  R1, R2 : Rec2;

begin
  null;
end;

-- { dg-do compile }
-- { dg-options "-O -gnatws" }

with Pack22_Pkg; use Pack22_Pkg;

procedure Pack22 is

   package Role_Map is new Bit_Map_Generic;

   type Role_List is new Role_Map.List;
   Roles_1 : Role_List;
   Roles_2 : Role_List;
   Roles_3 : Role_List;

begin
   Temp_buffer := (others => 1);
   Temp_Buffer(2) := (0);
   Roles_1 := Roles_2 xor Roles_3;
end;

package body Pack22_Pkg is

   package body Bit_Map_Generic is

      function "xor" (L, R : List) return List is
         Temp : List;
         for Temp'address use Temp_buffer'address;
      begin
         Temp.Bits := L.Bits xor R.Bits;
         Temp.Counter.Counter := 0;
         return Temp;
      end;

   end Bit_Map_Generic;

end Pack22_Pkg;

package Pack22_Pkg is

   type byte is mod 256;
   Temp_buffer : array (0..8) of byte:= (others => 0);
   for Temp_buffer'Alignment use 2;

   subtype Id is Short_integer;

   generic
      Dummy : Integer := 0;
   package Bit_Map_Generic is

      type List is private;
      function "xor" (L, R : List) return List;

   private
      type Offset_T is range 0 .. Id'Last;
      type Counter_T is new short_integer;
      for Counter_T'Size use 16;

      type Bit_List is array (Id range <>) of Boolean;
      pragma Pack (Bit_List);

      type List_Counter_T (Is_Defined : Boolean := True) is
         record
            Dummy : Boolean := False;
            case Is_Defined is
               when True =>
                  Counter : Counter_T := 0;
               when False =>
                  null;
            end case;
         end record;
      for List_Counter_T use
         record
            Is_Defined at 0 range 0 .. 7;
            Dummy at 1 range 0 .. 7;
            Counter at 2 range 0 .. 15;
         end record;

      type List is
         record
            Offset : Offset_T := Offset_T (1) - 1;
            Counter : List_Counter_T;
            Bits : Bit_List (1 .. 6);
         end record;
      for List use
         record
            Offset at 0 range 0 .. 15;
            Counter at 2 range 0 .. 31;
         end record;

      type Iterator is
         record
            No_More_Id : Boolean := True;
            Current_Id : Id;
            The_List : List;
         end record;

   end Bit_Map_Generic;

end Pack22_Pkg;