On Thu, 2026-05-07 at 09:20 +0200, Jakub Jelinek wrote:
> On Thu, May 07, 2026 at 01:35:07PM +0800, H.J. Lu wrote:
> > I got
> >
> > FAIL: gcc.dg/analyzer/divide-by-zero-6.c (test for warnings, line
> > 14)
> > FAIL: gcc.dg/analyzer/divide-by-zero-6.c at line 15 (test for
> > warnings, line 14)
> > FAIL: gcc.dg/analyzer/divide-by-zero-6.c (test for excess errors)
> > Excess errors:
> > /export/gnu/import/git/gitlab/x86-
> > gcc/gcc/testsuite/gcc.dg/analyzer/divide-by-zero-6.c:14:18:
> > warning: use of uninitialized value '*f.y' [CWE-457]
> > [-Wanalyzer-use-of-uninitialized-value]
>
> The warnings are correct, but I guess the test wasn't meant to test
> two
> completely different thing, one on 64-bit targets and one on 32-bit
> ones.
>
> struct foo { int x; int y; };
>
> has sizeof (8) on most targets (except on non-32-bit int), but the
> test
> was using __builtin_memset (f, 0, sizeof (f)) where f is a pointer.
> Now, this happens to clear the whole structure on 64-bit targets but
> only
> first half of it on 32-bit ones, so on 64-bit it emits the expected
> warning
> about division by zero, while on 32-bit about using uninitialized
> value.
>
> I think the testcase was meant to clear the whole structure on all
> arches,
> the following patch does that.
>
> Tested on x86_64-linux -m32/-m64, ok for trunk?
Thanks, LGTM
>
> 2026-05-07 Jakub Jelinek <[email protected]>
>
> * gcc.dg/analyzer/divide-by-zero-6.c (init_foo): Use sizeof
> (*f)
> rather than sizeof (f).
>
> --- gcc/testsuite/gcc.dg/analyzer/divide-by-zero-6.c.jj 2026-05-06
> 17:43:14.669261648 +0200
> +++ gcc/testsuite/gcc.dg/analyzer/divide-by-zero-6.c 2026-05-07
> 09:13:54.430980976 +0200
> @@ -5,7 +5,7 @@ struct foo { int x; int y; };
> void
> init_foo (struct foo *f)
> {
> - __builtin_memset (f, 0, sizeof (f));
> + __builtin_memset (f, 0, sizeof (*f));
> }
>
> int
>
>
> Jakub
>
