tree-inline: Simplify IPA-CP type conversion (PR 93385)

Hi,

when callers and callees do not quite agree on the type of a
parameter, usually with ill-defined K&R or with smilarly wrong LTO
input, IPA-CP can attempt to try and substitute a wrong type for a
parameter (see e.g. gcc.dg/torture/pr48063.c).  Function
tree_function_versioning attempts to handle this in order not to
create invalid gimple but it then creates the mapping using
setup_one_parameter which also handles the same situation to avoid
similar problems when inlining and in more defined way.

So this patch simply removes the conversion attempts in
tree_function_versioning itself.  It is helpful for my upcoming fix of
PR 93385 because then I do not need to teach
ipa_param_body_adjustments to distinguish between successful and
unsuccessful mappings - setup_one_parameter uses force_value_to_type
for conversions which simly maps the worst cases to zero.

Bootstrapped, LTO-bootstrapped and tested on x86_64-linux.  I assume
this should wait until GCC 11 stage 1 but note that if we want to
backport a fix for PR 93385 later, this will probably be a prerequisite.

So, OK for trunk in stage 1?

Thanks,

Martin


2020-04-21  Martin Jambor  <mjambor@suse.cz>

	PR ipa/93385
	* tree-inline.c (tree_function_versioning): Leave any type conversion
	of replacements to setup_one_parameter and its friend
	force_value_to_type.
---
 gcc/ChangeLog     |  7 +++++++
 gcc/tree-inline.c | 42 +++++-------------------------------------
 2 files changed, 12 insertions(+), 37 deletions(-)

On Wed, 22 Apr 2020, Martin Jambor wrote:

> Hi,
> 
> when callers and callees do not quite agree on the type of a
> parameter, usually with ill-defined K&R or with smilarly wrong LTO
> input, IPA-CP can attempt to try and substitute a wrong type for a
> parameter (see e.g. gcc.dg/torture/pr48063.c).  Function
> tree_function_versioning attempts to handle this in order not to
> create invalid gimple but it then creates the mapping using
> setup_one_parameter which also handles the same situation to avoid
> similar problems when inlining and in more defined way.
> 
> So this patch simply removes the conversion attempts in
> tree_function_versioning itself.  It is helpful for my upcoming fix of
> PR 93385 because then I do not need to teach
> ipa_param_body_adjustments to distinguish between successful and
> unsuccessful mappings - setup_one_parameter uses force_value_to_type
> for conversions which simly maps the worst cases to zero.
> 
> Bootstrapped, LTO-bootstrapped and tested on x86_64-linux.  I assume
> this should wait until GCC 11 stage 1 but note that if we want to
> backport a fix for PR 93385 later, this will probably be a prerequisite.
> 
> So, OK for trunk in stage 1?

OK for stage1.

Thanks,
Richard.

> Thanks,
> 
> Martin
> 
> 
> 2020-04-21  Martin Jambor  <mjambor@suse.cz>
> 
> 	PR ipa/93385
> 	* tree-inline.c (tree_function_versioning): Leave any type conversion
> 	of replacements to setup_one_parameter and its friend
> 	force_value_to_type.
> ---
>  gcc/ChangeLog     |  7 +++++++
>  gcc/tree-inline.c | 42 +++++-------------------------------------
>  2 files changed, 12 insertions(+), 37 deletions(-)
> 
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 1edb5f2d70b..2578b6251af 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,10 @@
> +2020-04-21  Martin Jambor  <mjambor@suse.cz>
> +
> +	PR ipa/93385
> +	* tree-inline.c (tree_function_versioning): Leave any type conversion
> +	of replacements to setup_one_parameter and its friend
> +	force_value_to_type.
> +
>  2020-04-18  Jeff Law  <law@redhat.com>
>  
>  	PR debug/94439
> diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
> index 26c23f504be..fb1850382af 100644
> --- a/gcc/tree-inline.c
> +++ b/gcc/tree-inline.c
> @@ -6260,46 +6260,14 @@ tree_function_versioning (tree old_decl, tree new_decl,
>  	  p = new_param_indices[p];
>  
>  	tree parm;
> -	tree req_type, new_type;
> -
>  	for (parm = DECL_ARGUMENTS (old_decl); p;
>  	     parm = DECL_CHAIN (parm))
>  	  p--;
> -	tree old_tree = parm;
> -	req_type = TREE_TYPE (parm);
> -	new_type = TREE_TYPE (replace_info->new_tree);
> -	if (!useless_type_conversion_p (req_type, new_type))
> -	  {
> -	    if (fold_convertible_p (req_type, replace_info->new_tree))
> -	      replace_info->new_tree
> -		= fold_build1 (NOP_EXPR, req_type, replace_info->new_tree);
> -	    else if (TYPE_SIZE (req_type) == TYPE_SIZE (new_type))
> -	      replace_info->new_tree
> -		= fold_build1 (VIEW_CONVERT_EXPR, req_type,
> -			       replace_info->new_tree);
> -	    else
> -	      {
> -		if (dump_file)
> -		  {
> -		    fprintf (dump_file, "    const ");
> -		    print_generic_expr (dump_file,
> -					replace_info->new_tree);
> -		    fprintf (dump_file,
> -			     "  can't be converted to param ");
> -		    print_generic_expr (dump_file, parm);
> -		    fprintf (dump_file, "\n");
> -		  }
> -		old_tree = NULL;
> -	      }
> -	  }
> -
> -	if (old_tree)
> -	  {
> -	    init = setup_one_parameter (&id, old_tree, replace_info->new_tree,
> -					id.src_fn, NULL, &vars);
> -	    if (init)
> -	      init_stmts.safe_push (init);
> -	  }
> +	gcc_assert (parm);
> +	init = setup_one_parameter (&id, parm, replace_info->new_tree,
> +				    id.src_fn, NULL, &vars);
> +	if (init)
> +	  init_stmts.safe_push (init);
>        }
>  
>    ipa_param_body_adjustments *param_body_adjs = NULL;
>