https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91707
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2021-01-21 00:00:00 |2021-12-15
Known to fail|11.0 |11.2.0, 12.0
--- Comment #11 from Martin Sebor <msebor at gcc dot gnu.org> ---
GCC 11 still issues the same -Wstringop-overflow as GCC 10 plus another one for
the call to md_copy_dims():
In function ‘real_from_complex_dims’,
inlined from ‘md_test’ at pr91707.c:14:4:
pr91707.c:7:13: warning: writing 8 bytes into a region of size 0
[-Wstringop-overflow=]
7 | odims[0] = 2;
| ~~~~~~~~~^~~
pr91707.c: In function ‘md_test’:
pr91707.c:13:9: note: destination object ‘dimsR.8’ of size 0
13 | long dimsR[D + 1];
| ^~~~~
In function ‘real_from_complex_dims’,
inlined from ‘md_test’ at pr91707.c:14:4:
pr91707.c:8:4: warning: ‘md_copy_dims’ accessing 34359738360 bytes in a region
of size 0 [-Wstringop-overflow=]
8 | md_copy_dims(D, odims + 1, idims);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pr91707.c: In function ‘md_test’:
pr91707.c:8:4: note: referencing argument 2 of type ‘long int *’
pr91707.c:2:13: note: in a call to function ‘md_copy_dims’
2 | extern void md_copy_dims(unsigned int D, long odims[D], const long
idims[D]);
| ^~~~~~~~~~~~
The second warning is for the md_copy_dims() call in the following IL:
<bb 5> [count: 0]:
md_copy_dims (4294967295, &MEM <unsigned char[0:18446744073709551615]> [(void
*)&dimsR.8 + 8B], idims_13(D));
__builtin___ubsan_handle_vla_bound_not_positive (&*.Lubsan_data1, 0);
<bb 6> [local count: 1073741824]:
dimsR.8 ={v} {CLOBBER};
return;
The first warning is gone in GCC 12 and only the second one remains. It's
triggered by the same md_copy_dims() call with the first argument in excess of
the size of the arrays passed to the function:
<bb 7> [count: 0]:
_29 = dimsR.1_23 + 8;
md_copy_dims (4294967295, _29, idims_13(D));
__builtin___ubsan_handle_vla_bound_not_positive (&*.Lubsan_data1, 0);
