Re: __attribute__ to selectively disable -Wmaybe-uninitialized

[mark_at_yahoo <markrubn@yahoo.com>]

On 10/23/20 1:38 PM, Segher Boessenkool wrote:
> Yes.  And you usually should make trivial changes to your program if the
> compiler warns, even if you consider that unnecessary -- just so that
> you will not miss other warnings!

> No, but you can write your code so that it more obviously does not use
> unitialised variables.  This is an Even Better Thing(tm).  The compiler
> will understand it, but much more importantly, human readers will
> understand it as well!

It's often (maybe always) possible to reorder/refactor the code as you 
suggest. Sometimes (maybe often) that results in convoluted logic and 
control flow, needlessly repeated code sections, gratuitous (possibly 
inline) functions, and the like. The cure being worse than the #pragma 
disease.


> -Wmaybe-uninitialized has a LOT of false positives if you use anything
> but the strictest, simplest control flow.  It's the nature of the beast.

That's the point. There will always be false positives. Sometimes the 
programmer *does* know more than the compiler. IMO GCC could benefit 
from a better way to selectively turn them off.


>> 5. I now see something similar was requested in 2012 in
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55288 but seems to have
>> been dismissed with a variation of #4.
> 
> It wasn't dismissed, that PR is still open.

Sorry, I was using "dismissed" colloquially. The response was 
dismissive, and from what I've been able to find nothing has been done 
in the succeeding 8 years.

But, yes, that's the nature of the open source (in general) and GCC (in 
particular) beast.

-- 
MARK
markrubn@yahoo.com