[Bug fortran/96711] Internal Compiler Error on NINT() Function

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96711

--- Comment #9 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Wed, Aug 19, 2020 at 09:36:32PM +0000, anlauf at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96711
> 
> --- Comment #8 from anlauf at gcc dot gnu.org ---
> A very quick hack seems to solve the issue for me.  For some reason the
> final fold_convert seems to create a problem.  Does anybody know why?
> It there a shorter solution?
> 
> diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
> index 2483f016d8e..deb3030b75d 100644
> --- a/gcc/fortran/trans-intrinsic.c
> +++ b/gcc/fortran/trans-intrinsic.c
> @@ -395,11 +395,26 @@ build_round_expr (tree arg, tree restype)
>      fn = builtin_decl_for_precision (BUILT_IN_LROUND, argprec);
>    else if (resprec <= LONG_LONG_TYPE_SIZE)
>      fn = builtin_decl_for_precision (BUILT_IN_LLROUND, argprec);
> +  else if (resprec >= argprec && resprec == 128)
> +    {
> +      /* Search for a real kind suitable as temporary for conversion.  */
> +      int kind = -1;
> +      for (int i = 0; kind < 0 && gfc_real_kinds[i].kind != 0; i++)
> +       if (gfc_real_kinds[i].mode_precision >= resprec)
> +         kind = gfc_real_kinds[i].kind;
> +      if (kind < 0)
> +       gfc_internal_error ("Could not find real kind with at least %d bits",
> +                           resprec);
> +      arg = fold_convert (gfc_float128_type_node, arg);
> +      fn = gfc_builtin_decl_for_float_kind (BUILT_IN_ROUND, kind);
> +    }
>    else
>      gcc_unreachable ();
> 
> -  return fold_convert (restype, build_call_expr_loc (input_location,
> -                                                fn, 1, arg));
> +  return convert (restype, build_call_expr_loc (input_location,
> +                                               fn, 1, arg));
> +  /* return fold_convert (restype, build_call_expr_loc (input_location, */
> +  /*                                            fn, 1, arg)); */
>  }

I tried an even uglier hack, and also got stumped by GIMPLE.
Jakub can probably shed some light on how to handle 
quad precision and GIMPLE.