https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104341
Bug ID: 104341
Summary: Bogus -Werror=array-bounds since
r12-2582-gb9cbf8c9e0bc72f5
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: marxin at gcc dot gnu.org
CC: msebor at gcc dot gnu.org
Target Milestone: ---
Reduced from qemu package:
$ cat acpi.i
int memcpy_src_u_0_0, acpi_sx_zsdt_acpi;
char acpi_sx_zsdt_buf_0_0;
static void *memcpy2(void *dest, void *, int) {
void *__trans_tmp_2 = dest;
union {
int u32[2];
} *dest_u = __trans_tmp_2;
dest_u->u32[0] = memcpy_src_u_0_0;
return 0;
}
void copy_from_user(void *dest) {
long __trans_tmp_4 = (long)dest, __trans_tmp_3 = __trans_tmp_4;
memcpy2((void *)__trans_tmp_3, 0, 0);
}
int acpi_sx_zsdt() {
copy_from_user(&acpi_sx_zsdt_acpi);
return acpi_sx_zsdt_buf_0_0;
}
$ gcc acpi.i -c -Werror=array-bounds -O2
In function ‘memcpy2’,
inlined from ‘copy_from_user’ at acpi.i:13:3,
inlined from ‘acpi_sx_zsdt’ at acpi.i:16:3:
acpi.i:8:18: error: array subscript ‘union <anonymous>[0]’ is partly outside
array bounds of ‘int[1]’ [-Werror=array-bounds]
8 | dest_u->u32[0] = memcpy_src_u_0_0;
| ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
acpi.i: In function ‘acpi_sx_zsdt’:
acpi.i:1:23: note: object ‘acpi_sx_zsdt_acpi’ of size 4
1 | int memcpy_src_u_0_0, acpi_sx_zsdt_acpi;
| ^~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
