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

[Mark Mitchell <mark at codesourcery dot com>]

Joseph S. Myers wrote:
> On Fri, 1 Sep 2006, Mark Mitchell wrote:
>
> > I think that this is a more fundamental problem.  Since we only have one node
> > for a type, the first use of a pointer type may point to a variable-length
> > array whose size isn't known at the point the pointer type is used.
> >
> > On that basis, I thin Jakub's patch is suspect for PR 21536, and that we
> > should not recur on pointer types.  Perhaps the middle-end should just ignore
> > the bounds for VLAs, and treat them as unknown, at least in some situations.
>
> I think front ends should be responsible for making sure that VLA sizes 
> get evaluated at the right time and replacing them with temporary 
> variables, rather than relying on SAVE_EXPRs getting evaluated at a 
> sensible time.

I think you've nailed it; that's exactly what we should do.

--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713