Re: [patch] fix wrong gimple code with ptr to forward vla

[Olivier Hainque <hainque at adacore dot com>]

Mark Mitchell wrote:
> If you made the C front end explictly declare the type, then the
> type-elaboration approach would work as expected, and Jakub's patch
> could be removed.  That would be a logically coherent approach, and
> we could always switch to Joseph's approach in the fullness of time.

> Perhaps Jakub would be willing to help with that, if you get stuck?

 That would be much appreciated, thanks.

 I'll have a first look as soon as possible, but as I said this is
 "new" code to me so will possible take a bit of time. It's also not
 yet entirely clear which exact set of constructs need to be addressed.

 What about C++, btw ? Do you think it would need inspection as well ?

 The testcase I posted is currently rejected, but maybe legal variants
 would be affected as well.

 Other languages ?

> I think that checking for non-TYPE_DECL ness is a little better than 
> anonymity; at least, we'd be checking for a semantic property.  However,
> given the situation outlined in the previous paragraph, it's pretty 
> questionable: we're admitting the existence of variable-sized types 
> without TYPE_DECLs, which means that there is no well-defined point at 
> which the bounds should be calculated.  In particular, I don't think 
> "the first time you encounter that type" is that well-defined.
> 
> But, I would be more accepting of the no-TYPE_DECL test than the no-name 
> test, if we have to choose between those two.

 Understood. Thanks for your feeddback.

 Olivier