> On Nov 5, 2021, at 11:17 AM, Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Fri, Nov 05, 2021 at 04:11:36PM +0000, Qing Zhao wrote:
>> 3076 if (TREE_CODE (TREE_TYPE (lhs)) != BOOLEAN_TYPE
>> 3077 && tree_fits_uhwi_p (var_size)
>> 3078 && (init_type == AUTO_INIT_PATTERN
>> 3079 || !is_gimple_reg_type (var_type))
>> 3080 && int_mode_for_size (tree_to_uhwi (var_size) * BITS_PER_UNIT,
>> 3081 0).exists ())
>> 3082 {
>> 3083 unsigned HOST_WIDE_INT total_bytes = tree_to_uhwi (var_size);
>> 3084 unsigned char *buf = (unsigned char *) xmalloc (total_bytes);
>> 3085 memset (buf, (init_type == AUTO_INIT_PATTERN
>> 3086 ? INIT_PATTERN_VALUE : 0), total_bytes);
>> 3087 tree itype = build_nonstandard_integer_type
>> 3088 (total_bytes * BITS_PER_UNIT, 1);
>>
>> The exact failing point is at function
>> “set_min_and_max_values_for_integral_type”:
>>
>> 2851 gcc_assert (precision <= WIDE_INT_MAX_PRECISION);
>>
>> For _Complex long double, “precision” is 256.
>> In GCC11, “WIDE_INT_MAX_PRECISION” is 192, in GCC12, it’s 512.
>> As a result, the above assertion failed on GCC11.
>>
>> I am wondering what’s the best fix for this issue in gcc11?
>
> Even for gcc 12 the above is wrong, you can't blindly assume that
> build_nonstandard_integer_type will work for arbitrary precisions,
> and even if it works that it will actually work.
> The fact that such a mode exist is one thing, but
> targetm.scalar_mode_supported_p should be tested for whether the mode
> is actually supported.
You mean “int_mode_for_size().exists()” is not enough to make sure
“build_nonstandard_integer_type” to be valid?
We should add “targetm.scalar_mode_supported_p” too ?
Qing
>
> Jakub
>
