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Re: RFA: New pass to delete unexecutable paths in the CFG
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On 11/09/11 02:00, Richard Guenther wrote:
>
>> So the question is do we want to proceed with any of this work?
>> If so I can update the patch, if not I'll go back to my warning
>> work :-)
>
> I think we do want to continue with this work - probably not
> removing the faulting dereference though. I'd say we add a
> noreturn __builtin_nullptr_deref () in place of it (eventually
> doing the path isolation you mentioned above) and warn about the
> ones that survive until RTL expansion (where we'd just expand it as
> *0 = 0).
Seems reasonable. Interestingly enough the path isolation part would
be a special case of the path isolation code I want to build anyway.
FWIW, there's other things which we probably want to handle in a
similar fashion. For example, out of range array references,
particularly those implied by PHIs with out of range indices.
>
> In fact, the warning part of it might be the most useful piece for
> our users ;)
Most definitely. Optimizing this stuff was merely a sideshow; I
believe the warning bits are far more useful.
Jeff
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