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

[chenglulu <chenglulu@loongson.cn>]

在 2024/3/18 下午5:34, Xi Ruoyao 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.c and
> gcc.dg/c23-stdarg-8.c to fail.
>
> Fix the issue by checking if arg.type is NULL, as r14-9503 explains.
>
> gcc/ChangeLog:
>
> 	PR target/114175
> 	* config/loongarch/loongarch.cc
> 	(loongarch_setup_incoming_varargs): Only skip
> 	loongarch_function_arg_advance for TYPE_NO_NAMED_ARGS_STDARG_P
> 	functions if arg.type is NULL.
> ---
>
> Bootstrapped and regtested on loongarch64-linux-gnu.  Ok for trunk?
>
>   gcc/config/loongarch/loongarch.cc | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
> index 70e31bb831c..57de8ef7d20 100644
> --- a/gcc/config/loongarch/loongarch.cc
> +++ b/gcc/config/loongarch/loongarch.cc
> @@ -767,7 +767,8 @@ loongarch_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);
I think it's important to add annotation information here:
     /* where there is no hidden return argument passed, arg.type

      is always NULL.  */

Others LTGM.

Thanks!

> -  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl)))
> +  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl))
> +      || arg.type != NULL_TREE)
>       loongarch_function_arg_advance (pack_cumulative_args (&local_cum), arg);
>   
>     /* Found out how many registers we need to save.  */