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?
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
