------- Comment #8 from joseph at codesourcery dot com 2010-03-15 15:17 -------
Subject: Re: [4.3/4.4 Regression] Optimization error on vectors
of uint64_t
On Mon, 15 Mar 2010, rguenth at gcc dot gnu dot org wrote:
> Joseph, is this a valid testcase?
>
> typedef unsigned long obj[1];
> extern void abort (void);
> int main()
> {
> obj X[2];
> X[1][0] = 67890;
> if (X[0][1] != 67890)
This access to X[0][1] looks like an out-of-bounds access that is
undefined behavior like the example in Annex J: "An array subscript is out
of range, even if an object is apparently accessible with the given
subscript (as in the lvalue expression a[1][7] given the declaration int
a[4][5]) (6.5.6).". (This originates in C90 DR#017; the example was added
in C90 TC1.)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41630
