https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98548
Bug ID: 98548
Summary: missing warning on strcmp with a nonstring member
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
-Wstringop-overread detects the misuse of the nonstring array as a strcmp
argument in f() but not in g(). Both calls should trigger a warning.
$ cat b.c && gcc -O2 -S -Wall -Wextra b.c
struct A
{
char a[4] __attribute__ ((nonstring));
char b[8];
};
int f (void)
{
extern struct A a;
return 0 == __builtin_strcmp (a.a, a.b); // warning (good)
}
int g (struct A *p)
{
return 0 == __builtin_strcmp (p->a, p->b); // missing warning
}
b.c: In function ‘f’:
b.c:10:15: warning: ‘__builtin_strcmp’ argument 1 declared attribute
‘nonstring’ is smaller than the specified bound 8 [-Wstringop-overread]
10 | return 0 == __builtin_strcmp (a.a, a.b);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
b.c:3:8: note: argument ‘a’ declared here
3 | char a[4] __attribute__ ((nonstring));
| ^
