[Bug other/38077] strict aliasing is not controllable via the option pragma or is not documented that way

[Bug other/38077] strict aliasing is not controllable via the option pragma or is not documented that way

[bernd.edlinger at hotmail dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38077

Bernd Edlinger <bernd.edlinger at hotmail dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bernd.edlinger at hotmail dot de

--- Comment #2 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
As of current 4.9 trunk, that may have changed a bit.
but it still does not do what one would expect:

struct s
{
   int x:8;
   int y:24;
};

#pragma GCC push
#pragma GCC optimize ("strict-volatile-bitfields")
int foo(volatile struct s *x)
{
  return x->x;
}
#pragma GCC pop

#pragma GCC push
#pragma GCC optimize ("no-strict-volatile-bitfields")
int bar(volatile struct s *x)
{
  return x->x;
}
#pragma GCC pop


Both foo and bar are compiled as if -fno-strict-volatile-bitfields
was used on gcc-invocation. Whatever pragma is used last, wins...
push/pop are ignored, and does not restore the original settings.

[Bug other/38077] strict aliasing is not controllable via the option pragma

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38077

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Bernd Edlinger from comment #2)
> As of current 4.9 trunk, that may have changed a bit.
> but it still does not do what one would expect:

That is a different issue ...

[Bug other/38077] strict aliasing is not controllable via the option pragma

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38077

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to fail|                            |5.4.0
      Known to work|                            |5.5.0, 6.1.0
   Target Milestone|---                         |5.5
         Resolution|---                         |FIXED

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This was fixed for GCC 5.5.0 by r5-10168-g26736ac3d17699 and GCC 6.1.0+ by
r6-5413-g9dc39706b4afc3 .

[Bug other/38077] strict aliasing is not controllable via the option pragma

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38077

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> (In reply to Bernd Edlinger from comment #2)
> > As of current 4.9 trunk, that may have changed a bit.
> > but it still does not do what one would expect:
> 
> That is a different issue ...

That was fixed in GCC 5.1.0 (I have not looked into what fixed it though).

[Bug other/38077] strict aliasing is not controllable via the option pragma

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38077

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #4)
> This was fixed for GCC 5.5.0 by r5-10168-g26736ac3d17699 and GCC 6.1.0+ by
> r6-5413-g9dc39706b4afc3 .

I should say that was the last patch which was needed to fix this, there was
most likely others that happened beforehand.