Martin Husemann <martin@NetBSD.org> writes:

> That made me curious, and experiments show that a kernel compiled with
> anything != -O2 crashes with alignment faults or illegal instructions.
> 
> Maybe we should drop back to gcc 3.3.6 for now as default, untill this
> code gen issues have been resolved?

I don't think this is a reason to change the default, just to debug
the failures. In my experience (mostly over in ppc-land), there are
lots of bits of inline asm in platform-specific code that are written
with certain assumptions about what the compiler is going to do, and
changing the compiler or the optimization flags affects those.

That said, binary-search on the object files is pretty effective for
finding out exactly which ones have problems with optimization other
than -O2.

        - Nathan