Re: PR84229 part 1: Avoid cloning of functions that calls va_arg_pack

[Jakub Jelinek <jakub@redhat.com>]

On Wed, Feb 21, 2018 at 08:09:28PM +0100, Jan Hubicka wrote:
> --- ipa-cp.c	(revision 257844)
> +++ ipa-cp.c	(working copy)
> @@ -630,6 +630,24 @@ determine_versionability (struct cgraph_
>        reason = "calls comdat-local function";
>      }
>  
> +  /* Functions calling BUILT_IN_VA_ARG_PACK and BUILT_IN_VA_ARG_PACK_LEN
> +     works only when inlined.  Cloning them may still lead to better code

s/works/work/

> +     becuase ipa-cp will not give up on cloning further.  If the function is

s/becuase/because/

> +     external this however leads to wrong code becuase we may end up producing

s/becuase/because/

> +     offline copy of the function.  */
> +  if (DECL_EXTERNAL (node->decl))
> +    for (cgraph_edge *edge = node->callees; !reason && edge;
> +	 edge = edge->next_callee)
> +      if (DECL_BUILT_IN (edge->callee->decl)
> +	  && DECL_BUILT_IN_CLASS (edge->callee->decl) == BUILT_IN_NORMAL)
> +        {
> +	  if (DECL_FUNCTION_CODE (edge->callee->decl) == BUILT_IN_VA_ARG_PACK)
> +	    reason = "external function which calls va_arg_pack";
> +	  if (DECL_FUNCTION_CODE (edge->callee->decl)
> +	      == BUILT_IN_VA_ARG_PACK_LEN)
> +	    reason = "external function which calls va_arg_pack_len";
> +        }
> +
>    if (reason && dump_file && !node->alias && !node->thunk.thunk_p)
>      fprintf (dump_file, "Function %s is not versionable, reason: %s.\n",
>  	     node->dump_name (), reason);

Do you have a testcase for this, or is it LTO with too large input?

	Jakub