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.
Jakub
