[Bug c/17913] [4.0 Regression] ICE jumping into statement expression

[loki at inf dot u-szeged dot hu]

------- Additional Comments From loki at inf dot u-szeged dot hu  2004-10-28 06:42 -------
(In reply to comment #7)
> > Surely this is not valid?
> 
> The validity is the subject of bug 772 and the long thread linked from 
> there.  This bug is for a particular ICE which is a regression; whether 
> the code is valid or invalid depends on whether any resolution suggested 
> in bug 772 or elsewhere is adopted.

Yes. I agree with you. This is a regression in ?: operator evaluation. I didn't
want to change anything about bug 772.

[...]
> First, you need to check for switch statements 
> jumping into the statement expression.  Second, if inside a statement 
> expression you encounter a reference to an undeclared label, you don't 
> know whether it refers to one later within that statement expression or 
> one outside in the function (and in an address-of-label context, both 
> could reasonably be valid) so don't know in what scope to declare the 
> label (or, if there's one outside already seen with that name, whether the 
> new one is a reference to that label or to a new local one).  For that 
> reason I think it's best to keep the current scoping rules and have a 
> separate check for any form of jumps into statement expressions, with 
> jumps by computed goto explicitly runtime undefined.  (While jumps in from 
> longjmp might be OK.)

Yes, you are right. I missed some cases. I'm working on it...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17913