> On Apr 14, 2025, at 16:35, Marek Polacek <pola...@redhat.com> wrote:
>
> On Mon, Apr 14, 2025 at 08:28:55PM +0000, Qing Zhao wrote:
>> C_MAYBE_CONST_EXPR is a C FE operator that will be removed by c_fully_fold.
>> In c_fully_fold, it assumes that operands of function calls have already
>> been folded. However, when we build call to .ACCESS_WITH_SIZE, all its
>> operands are not fully folded. therefore the C FE specific operator is
>> passed to middle-end.
>>
>> In order to fix this issue, fully fold the parameters before building the
>> call to .ACCESS_WITH_SIZE.
>>
>> I am doing the bootstrap and regression testing on both X86 and aarch64 now.
>> Okay for trunk if testing going well?
>>
>> thanks.
>>
>> Qing
>>
>> PR c/119717
>>
>> gcc/c/ChangeLog:
>>
>> * c-typeck.cc (build_access_with_size_for_counted_by): Fully fold the
>> parameters for call to .ACCESS_WITH_SIZE.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.dg/pr119717.c: New test.
>> ---
>> gcc/c/c-typeck.cc | 8 ++++++--
>> gcc/testsuite/gcc.dg/pr119717.c | 24 ++++++++++++++++++++++++
>> 2 files changed, 30 insertions(+), 2 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.dg/pr119717.c
>>
>> diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
>> index 3870e8a1558..dd176d96a41 100644
>> --- a/gcc/c/c-typeck.cc
>> +++ b/gcc/c/c-typeck.cc
>> @@ -3013,12 +3013,16 @@ build_access_with_size_for_counted_by (location_t
>> loc, tree ref,
>> gcc_assert (c_flexible_array_member_type_p (TREE_TYPE (ref)));
>> /* The result type of the call is a pointer to the flexible array type. */
>> tree result_type = c_build_pointer_type (TREE_TYPE (ref));
>> + tree first_param
>> + = c_fully_fold (array_to_pointer_conversion (loc, ref), FALSE, NULL);
>> + tree second_param
>> + = c_fully_fold (counted_by_ref, FALSE, NULL);
>
> Why FALSE? Just use false. You can also use nullptr rather than NULL now.
Just replaced FALSE with false.
I am keeping NULL to be consistent with other calls to c_fully_fold in the same
file.
And testing the new version now.
Thanks a lot.
(With FALSE, the compilation went fine…)
Qing
>
>> tree call
>> = build_call_expr_internal_loc (loc, IFN_ACCESS_WITH_SIZE,
>> result_type, 6,
>> - array_to_pointer_conversion (loc, ref),
>> - counted_by_ref,
>> + first_param,
>> + second_param,
>> build_int_cst (integer_type_node, 1),
>> build_int_cst (counted_by_type, 0),
>> build_int_cst (integer_type_node, -1),
>> diff --git a/gcc/testsuite/gcc.dg/pr119717.c
>> b/gcc/testsuite/gcc.dg/pr119717.c
>> new file mode 100644
>> index 00000000000..e5eedc567b3
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/pr119717.c
>> @@ -0,0 +1,24 @@
>> +/* PR c/119717 */
>> +/* { dg-additional-options "-std=c23" } */
>> +/* { dg-do compile } */
>> +
>> +struct annotated {
>> + unsigned count;
>> + [[gnu::counted_by(count)]] char array[];
>> +};
>> +
>> +[[gnu::noinline,gnu::noipa]]
>> +static unsigned
>> +size_of (bool x, struct annotated *a)
>> +{
>> + char *p = (x ? a : 0)->array;
>> + return __builtin_dynamic_object_size (p, 1);
>> +}
>> +
>> +int main()
>> +{
>> + struct annotated *p = __builtin_malloc(sizeof *p);
>> + p->count = 0;
>> + __builtin_printf ("the bdos whole is %ld\n", size_of (0, p));
>> + return 0;
>> +}
>> --
>> 2.31.1
>>
>
> Marek
