[Bug ada/33889] New: Inefficient code expansion for extended return statement

[Bug ada/33889] New: Inefficient code expansion for extended return statement

[vgodunko at rostel dot ru]

For this simple code

package P is
   type T is limited interface;
   function F return not null access T'Class;
end P;

package body P is
   function X return not null access T'Class;
   pragma Import (C, X);
   function F return not null access T'Class is
   begin
      return Result : not null access T'Class := X do
         null;
      end return;
   end F;
end P;

GNAT generate to many RTL calls:

$ gcc -O2 -S -gnatdg p.adb

   function p__f return not null access p__t'class is

      procedure p__f___clean is
      begin
         system__soft_links__abort_defer.all;
         system__soft_links__complete_master.all;
         system__soft_links__abort_undefer.all;
         return;
      end p__f___clean;
   begin
      system__soft_links__enter_master.all;
      R3b : declare
         _master : constant integer := 
           system__soft_links__current_master.all;
         T4bM : integer renames _master;
         [subtype p__T1s is access not null p__TtC]
         result : not null not null access p__t'class := p__T1s!(
           $ada__tags__displace (system__address!(x), p__tP));
      begin
            null;
         return p__T1s!($ada__tags__displace (system__address!(result), 
           p__tP));
      end R3b;
   at end
      p__f___clean;
   end p__f;

Computation of accessibility level don't needed in this case.


-- 
           Summary: Inefficient code expansion for extended return statement
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: vgodunko at rostel dot ru
  GCC host triplet: x86-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33889

[Bug ada/33889] Inefficient code expansion for extended return statement

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33889

[Bug ada/33889] Inefficient code expansion for extended return statement

[charlet at gcc dot gnu dot org]

------- Comment #1 from charlet at gcc dot gnu dot org  2008-05-12 22:05 -------
This is not accessibility level which is computed here, but dynamic task
master level, in case your interface is a synchronized interface.

You can already use pragma Restrictions (No_Task_Hierarchy) if you do not want
this
code expansion.

Arno


-- 

charlet at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |WONTFIX


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33889