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Re: -Wuninitialized issues
On Tuesday 01 November 2005 13:17, Jeffrey A Law wrote:
> Possibly a useful thing to have, but I don't think we want to put
> the burden of detecting uninitialized variables onto each
> optimizer :-)
> I think false positives are inevitable if we attempt to solve the
> problems Mark is complaining about. That's part of the reason why
> I think this needs to be switch controlled.
> Your example is probably derived from C code which looks something
> like this:
Yeah, it's gcc.dg/m-un-1.c, IIRC.
> Clearly the message could be better, but it's easy to see how this
> warning distinguishes itself from the "blah may be used uninitialized in
> this function" warning we give in other cases. We clearly state that
> it appeared to be used uninitialized, but optimizations changed that
We won't get perfect answers, which is fine given the nature of the
problem. However, I would like, to get *consistent* answers. If we
decide to re-organize the optimization pipeline, we should not be getting
different -Wuninitialized behaviour. Perhaps that's an easier problem to
solve. For instance, for GCC bootstraps we could ignore the warning when
it's from "... but was later optimized away ...".