https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106927
Bug ID: 106927
Summary: false-positive -Werror=restrict warnings for memmove
(calling memcpy) within array
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc at boris dot fau.re
Target Milestone: ---
When compiling the following code with -Werror=restrict, gcc complains:
$cat foo.c
#include <string.h>
int main (void)
{
char *s = "abcdefghijklmnopqrstuvwxyz012345";
size_t d = strlen(s);
__builtin_memmove(s, s + 1, d - 1);
return 0;
}
$ gcc -c -O2 -Werror=restrict -o foo.o foo.c
foo.c: In function 'main':
foo.c:8:5: error: '__builtin_memcpy' accessing 31 bytes at offsets 0 and 1
overlaps 30 bytes at offset 1 [-Werror=restrict]
8 | __builtin_memmove(s, s + 1, d - 1);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This was reproduced on gentoo with gcc-11.3.0, on RHEL9 with gcc-11.2.1, on
debian bullseye with gcc-12.2.0, on debian buster with gcc-9.5.0, RHEL8 with
gcc-8.5.0.
Please note that, on gcc-12.2.0, without -O2, the compilation succeeds.
