[Bug libstdc++/17627] M68060 fails with libstdc++-v3/config/cpu/m68k/atomicity.h

["joel at oarcorp dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From joel at oarcorp dot com  2004-11-03 21:09 -------
Subject: Re:  M68060 fails with libstdc++-v3/config/cpu/m68k/atomicity.h

bkoz at gcc dot gnu dot org wrote:
> ------- Additional Comments From bkoz at gcc dot gnu dot org  2004-11-03 00:12 -------
> 
> Joel, you might want to talk to the m68k maintainers. 
> 
> Take your pick:
> m68hc11 port            Stephane Carrez         stcarrez@nerim.fr
> m68k port (?)           Jeff Law                law@redhat.com
> m68k-motorola-sysv port Philippe De Muyter      phdm@macqel.be
> 
> Since you are the rtems maintainer, I'm expecting you to be on top of fixing
> this, since it's currently seen as a m68k-rtems bug.
> 
> This bug hasn't been framed in a clear manner, IMHO. There's no test case, no
> patch file. If it's a generic m68k problem with 68060 and libstdc++ atomicity,
> it should be marked as such (and not rtems-specific.) If this has nothing to do
> with libstdc++, but instead has something to do with gcc or rtems, well, the
> category on this bug should reflect this.
> 
> Hope this helps.

It does and just reiterates what shuold have been done when it was 
reported.  Chris is going to try to put together a test case.

What we are concerned about is that it is more than likely a generic
problem.  Very few problems are RTEMS specific at this level.  Chris
believes that a 16-bit variable may be allocated on the stack and
this would result in it being misaligned.  This is likely the issue.
The MC68060 can't do misaligned accesses for the instruction in 
question.  On a MC68060 without software emulation of missing 
instructions, then you get a fault.

So the concern is that this is a generic m680x0 issue with
letting the stack get misaligned and it just gets caught in
this one very complex C++ scenario.

Don't close it yet and give Chris a chance to give a test case.

--joel



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17627