[PR debug/77773] segfault when compiling __simd64_float16_t with -g

Richard Biener richard.guenther@gmail.com
Thu Oct 27 07:35:00 GMT 2016

On Wed, Oct 26, 2016 at 9:17 PM, Aldy Hernandez <aldyh@redhat.com> wrote:
> The following one-liner segfaults on arm-eabi when compiled with
> -mfloat-abi=hard -g:
>         __simd64_float16_t usingit;
> The problem is that the pretty printer (in simple_type_specificer()) is
> dereferencing a NULL result from c_common_type_for_mode:
>           int prec = TYPE_PRECISION (t);
>           if (ALL_FIXED_POINT_MODE_P (TYPE_MODE (t)))
>             t = c_common_type_for_mode (TYPE_MODE (t), TYPE_SATURATING (t));
>           else
>             t = c_common_type_for_mode (TYPE_MODE (t), TYPE_UNSIGNED (t));
>           if (TYPE_NAME (t))
> The type in question is:
>         <real_type 0x7fffefdeb150 HF ...>
> which corresponds to HFmode and which AFAICT, does not have a type by
> design.
> I see that other uses of *type_for_node() throughout the compiler check the
> result for NULL, so perhaps we should do the same here.
> The attached patch fixes the problem.
> OK for trunk?

Your added assert shows another possible issue - can you fix this by assigning
the result of c_common_type_for_mode to a new variable, like common_t and
use that for the TYPE_NAME (...) case?  I think this was what was intended.


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