https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83842
Bug ID: 83842
Summary: extend -Wmemset-elt-size to memcpy and memmove
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
The -Wmemset-elt-size warning is helpful in pointing out the mistake of passing
the number of array elements to memset rather than the number of bytes. The
same mistake can happen when calling memcpy and memmove. It would be useful to
extend the -Wmemset-elt-size to those functions as well (either under the same
option or under a new one).
$ cat z.c && gcc -S -Wall z.c
int a[2];
void f (void)
{
__builtin_memset (a, 0, 2); // -Wmemset-elt-size (good)
}
void g (const int *p)
{
__builtin_memcpy (a, p, 2); // missing -Wmemcpy-elt-size
}
void h0 (void)
{
__builtin_memmove (a, &a[1], 2); // missing -Wmemmove-elt-size
}
void h1 (void)
{
__builtin_memmove (&a[1], a, 2); // missing -Wmemmove-elt-size
}
z.c: In function ‘f’:
z.c:5:3: warning: ‘memset’ used with length equal to number of elements without
multiplication by element size [-Wmemset-elt-size]
__builtin_memset (a, 0, 2); // -Wmemset-elt-size (good)
^~~~~~~~~~~~~~~~
