Bug#630441: g++-4.6 miscompilation

[Miles Bader <miles@gnu.org>]

Philip Ashmore <contact@philipashmore.com> writes:
> It appears that gcc-4.6 (and clang for that matter) make some dodgy
> decisions about what appear to be references to temporaries created
> during optimization.

You don't seem to have addressed the issue raised by Matthias Klose in
the bug thread though:  specifically, whether this is truly a compiler
problem, or simply buggy code exposed by the newer compilers.

That it works as intended with older compilers or -O0 isn't enough to
show that -- it's very common for buggy code to work correctly for a
long time, and then suddenly stop working when a new compiler release
uses more aggressive [but correct] optimization.

It seems like an important step here would be to reduce this down to a
minimal test case.

[The fact that both newer versions of gcc and clang show the same
behavior does suggest that maybe it's the application code which is
buggy.]

-Miles

-- 
One of the lessons of history is that nothing is often a good thing to
do, and always a clever thing to say.  -- Will Durant