Q: middle-end problem when variadic builtins promote float to double

[Richard Guenther]

On 7/8/07, Kaveh R. GHAZI <ghazi@caip.rutgers.edu> wrote:
> On Sat, 7 Jul 2007, Joseph S. Myers wrote:
>
> > No, that's something else entirely (a "float" old-style parameter
> > declaration corresponds to a "double" argument in a prototype).  It's
> > convert_arguments that handles converting to prototype types and default
> > argument promotions for arguments not covered by a prototype (including
> > those in the ... of a variadic function).
> >
> >       else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
> >                && (TYPE_PRECISION (TREE_TYPE (val))
> >                    < TYPE_PRECISION (double_type_node))
> >                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
> >         /* Convert `float' to `double'.  */
> >         argarray[parmnum] = convert (double_type_node, val);
>
>
> Ah perfect, thanks.  I'm thinking something like what's below.  I'll move
> it over to gcc-patches and add a ChangeLog if it passes testing.
>
> Thanks for your help!
>
>                 --Kaveh
>
>
> diff -rup orig/egcc-SVN20070706/gcc/c-typeck.c egcc-SVN20070706/gcc/c-typeck.c
> --- orig/egcc-SVN20070706/gcc/c-typeck.c        2007-06-30 23:02:59.000000000 -0400
> +++ egcc-SVN20070706/gcc/c-typeck.c     2007-07-07 21:26:33.982197838 -0400
> @@ -2394,6 +2394,8 @@ convert_arguments (int nargs, tree *arga
>  {
>    tree typetail, valtail;
>    int parmnum;
> +  const bool type_generic =
> +    !!lookup_attribute ("type generic", TYPE_ATTRIBUTES(TREE_TYPE (fundecl)));
>    tree selector;
>
>    /* Change pointer to function to the function itself for
> @@ -2585,8 +2587,13 @@ convert_arguments (int nargs, tree *arga
>                && (TYPE_PRECISION (TREE_TYPE (val))
>                    < TYPE_PRECISION (double_type_node))
>                && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (TREE_TYPE (val))))
> -       /* Convert `float' to `double'.  */
> -       argarray[parmnum] = convert (double_type_node, val);
> +        {
> +         /* Convert `float' to `double'.  */
> +         if (type_generic)
> +           argarray[parmnum] = val;
> +         else
> +           argarray[parmnum] = convert (double_type_node, val);
> +       }
>        else if ((invalid_func_diag =
>                 targetm.calls.invalid_arg_for_unprototyped_fn (typelist, fundecl, val)))
>         {

So type-generic is supposed to apply to scalar floating point types
only?  Btw. you need to add documentation for this function attribute.

Richard.