[PATCH] c: Suppress -Wdeprecated-non-prototype warnings for builtins

[Richard Sandiford]

Florian Weimer <fweimer@redhat.com> writes:
> Builtins defined with BT_FN_INT_VAR etc. show as functions without
> a prototype and trigger the warning.
>
> gcc/c/
>
> 	PR c/119950
> 	* c-typeck.cc (convert_arguments): Check for built-in
> 	function declaration before warning.
>
> gcc/testsuite/
>
> 	* gcc.dg/Wdeprecated-non-prototype-5.c: New test.
>
> ---
>  gcc/c/c-typeck.cc                                  |  3 ++-
>  gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c | 14 ++++++++++++++
>  2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
> index 55d896e02df..f8d1f711513 100644
> --- a/gcc/c/c-typeck.cc
> +++ b/gcc/c/c-typeck.cc
> @@ -4342,7 +4342,8 @@ convert_arguments (location_t loc, vec<location_t> arg_loc, tree fntype,
>  	  builtin_typetail = NULL_TREE;
>  	}
>  
> -      if (!typetail && parmnum == 0 && !TYPE_NO_NAMED_ARGS_STDARG_P (fntype))
> +      if (!typetail && parmnum == 0 && !TYPE_NO_NAMED_ARGS_STDARG_P (fntype)
> +	  && !fndecl_built_in_p (fundecl))

This is causing gcc.c-compile/callind.c and others to segfault on
aarch64, since fundecl can be null for indirect calls.

Thanks,
Richard

>  	{
>  	  auto_diagnostic_group d;
>  	  bool warned;
> diff --git a/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c b/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c
> new file mode 100644
> index 00000000000..b231a74cebe
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-Wdeprecated-non-prototype" } */
> +
> +static inline
> +int f (int x)
> +{
> +  return __builtin_constant_p (x);
> +}
> +
> +static inline
> +int g (double x)
> +{
> +  return __builtin_isfinite (x);
> +}
>
> base-commit: 0035613389a939043d654aea7a76faae95f69422