Messages in this thread | | | Date | Wed, 27 Jun 2007 13:19:48 +0100 | From | Al Viro <> | Subject | Re: [PATCH 16/16] fix handling of integer constant expressions |
| |
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... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |