On Wed, Jun 27, 2007 at 08:52:45PM +0900, Neil Booth wrote:
> Al Viro wrote:-
>
> >
> > sparse simply doesn't check that. We don't have anything resembling
> > support of VLA. Note that check for integer constant expression
> > has nothing to do with that;
> >
> > int x[(int)(0.6 + 0.6)];
> >
> > is valid (if stupid).
>
> It isn't valid; it fails the test twice. Both 0.6 are not "immediate
> operands of casts". Their sum is, but that's irrelevant.
> Therefore the dimension is not an ICE and a diagnostic is required.
Egads... After rereading that... What a mess.
int foo(void)
{
static int a[1][0,2];
}
is, AFAICS, allowed. Reason:
int a[0,2]
is a VLA due to 6.7.5.2[4] (0,2 is not an ICE). However, due to the language
in the same section,
int a[1][0,2]
is *not* a VLA, since (a) 2 is an ICE and (b) its element type "has a known
constant size" (it does - the value of 0,2 is certainly guaranteed to be 2).
I.e., it's VM type, but not a VLA. I.e. only the first part of 6.7.5.2[2]
applies and we are actually fine.
So we can have a static single-element array of int [0,2], but
not a plain static int [0,2]. Lovely, that...
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