[PATCH] handle VLA of zero length arrays and vice versa (PR 99121)

[Jakub Jelinek]

On Thu, Feb 18, 2021 at 07:00:52PM +0100, Jakub Jelinek wrote:
> > The size of the VLA is zero regardless of its bound and accessing
> > it is invalid so the warning is expected.
> 
> Yes, some warning, but not the one you are giving, that is nonsensical.
> Array subscript 0 is not outside of array bounds of struct S[n], a[anything]
> will still be zero sized and will not be problematic.

Scalar objects with zero size will always have that zero size,
similarly arrays thereof (constant or variable sized).
So the warning should be simply if eltsize == 0,
check if the access is before or after the object and complain
that a memory access is done before or after a zero sized object %qD.

	Jakub