Re: [PATCH] mips: Fix C23 (...) functions returning large aggregates [PR114175]

[YunQiang Su <syq@gcc.gnu.org>]

Xi Ruoyao <xry111@xry111.site> 于2024年3月20日周三 15:12写道：
>
> We were assuming TYPE_NO_NAMED_ARGS_STDARG_P don't have any named
> arguments and there is nothing to advance, but that is not the case
> for (...) functions returning by hidden reference which have one such
> artificial argument.  This is causing gcc.dg/c23-stdarg-{6,8,9}.c to
> fail.
>
> Fix the issue by checking if arg.type is NULL, as r14-9503 explains.
>
> gcc/ChangeLog:
>
>         PR target/114175
>         * config/mips/mips.cc (mips_setup_incoming_varargs): Only skip
>         mips_function_arg_advance for TYPE_NO_NAMED_ARGS_STDARG_P
>         functions if arg.type is NULL.
> ---
>
> Bootstrapped and regtested on mips64el-linux-gnuabi64.  Ok for trunk?
>

Thanks. LGTM.

>  gcc/config/mips/mips.cc | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc
> index 68e2ae8d8fa..ce764a5cb35 100644
> --- a/gcc/config/mips/mips.cc
> +++ b/gcc/config/mips/mips.cc
> @@ -6834,7 +6834,13 @@ mips_setup_incoming_varargs (cumulative_args_t cum,
>       argument.  Advance a local copy of CUM past the last "real" named
>       argument, to find out how many registers are left over.  */
>    local_cum = *get_cumulative_args (cum);
> -  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl)))
> +
> +  /* For a C23 variadic function w/o any named argument, and w/o an
> +     artifical argument for large return value, skip advancing args.
> +     There is such an artifical argument iff. arg.type is non-NULL
> +     (PR 114175).  */
> +  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl))
> +      || arg.type != NULL_TREE)
>      mips_function_arg_advance (pack_cumulative_args (&local_cum), arg);
>
>    /* Found out how many registers we need to save.  */
> --
> 2.44.0
>