Re: [PATCH] Fix ICE with va_arg (PR tree-optimization/69162)

[Richard Biener <rguenther at suse dot de>]

On Thu, 7 Jan 2016, Jakub Jelinek wrote:

> Hi!
> 
> The addition of IFN_VA_ARG which is only during stdarg pass lowered
> introduced ICE on the following testcase.  The problem is that
> we expected that the type the first argument of the internal call points
> to will remain the one that used to be there during gimplification, but
> as pointer conversions are useless, that is not guaranteed, it can become
> void * or any other pointer type.
> 
> Fixed by remembering the type on another argument.
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2016-01-07  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR tree-optimization/69162
> 	* gimplify.c (gimplify_va_arg_expr): Encode original type of
> 	valist argument in another argument.
> 	(gimplify_modify_expr): Adjust for the above change.  Cleanup.
> 	* tree-stdarg.c (expand_ifn_va_arg_1): Use new 3rd argument
> 	to determine the va_list type, build a MEM_REF instead of
> 	build_fold_indirect_ref.
> 
> 	* gcc.dg/pr69162.c: New test.
> 
> --- gcc/gimplify.c.jj	2016-01-04 14:55:53.000000000 +0100
> +++ gcc/gimplify.c	2016-01-07 15:19:17.283215609 +0100
> @@ -4724,12 +4724,12 @@ gimplify_modify_expr (tree *expr_p, gimp
>  	  tree type = TREE_TYPE (call);
>  	  tree ap = CALL_EXPR_ARG (call, 0);
>  	  tree tag = CALL_EXPR_ARG (call, 1);
> +	  tree aptag = CALL_EXPR_ARG (call, 2);
>  	  tree newcall = build_call_expr_internal_loc (EXPR_LOCATION (call),
>  						       IFN_VA_ARG, type,
>  						       nargs + 1, ap, tag,
> -						       vlasize);
> -	  tree *call_p = &(TREE_OPERAND (*from_p, 0));
> -	  *call_p = newcall;
> +						       aptag, vlasize);
> +	  TREE_OPERAND (*from_p, 0) = newcall;
>  	}
>      }
>  
> @@ -11501,7 +11501,7 @@ gimplify_va_arg_expr (tree *expr_p, gimp
>    tree promoted_type, have_va_type;
>    tree valist = TREE_OPERAND (*expr_p, 0);
>    tree type = TREE_TYPE (*expr_p);
> -  tree t, tag;
> +  tree t, tag, aptag;
>    location_t loc = EXPR_LOCATION (*expr_p);
>  
>    /* Verify that valist is of the proper type.  */
> @@ -11555,7 +11555,10 @@ gimplify_va_arg_expr (tree *expr_p, gimp
>      }
>  
>    tag = build_int_cst (build_pointer_type (type), 0);
> -  *expr_p = build_call_expr_internal_loc (loc, IFN_VA_ARG, type, 2, valist, tag);
> +  aptag = build_int_cst (TREE_TYPE (valist), 0);
> +
> +  *expr_p = build_call_expr_internal_loc (loc, IFN_VA_ARG, type, 3,
> +					  valist, tag, aptag);
>  
>    /* Clear the tentatively set PROP_gimple_lva, to indicate that IFN_VA_ARG
>       needs to be expanded.  */
> --- gcc/tree-stdarg.c.jj	2016-01-04 14:55:52.000000000 +0100
> +++ gcc/tree-stdarg.c	2016-01-07 15:20:14.340424740 +0100
> @@ -1018,7 +1018,7 @@ expand_ifn_va_arg_1 (function *fun)
>      for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
>        {
>  	gimple *stmt = gsi_stmt (i);
> -	tree ap, expr, lhs, type;
> +	tree ap, aptype, expr, lhs, type;
>  	gimple_seq pre = NULL, post = NULL;
>  
>  	if (!gimple_call_ifn_va_arg_p (stmt))
> @@ -1028,9 +1028,12 @@ expand_ifn_va_arg_1 (function *fun)
>  
>  	type = TREE_TYPE (TREE_TYPE (gimple_call_arg (stmt, 1)));
>  	ap = gimple_call_arg (stmt, 0);
> +	aptype = TREE_TYPE (gimple_call_arg (stmt, 2));
> +	gcc_assert (POINTER_TYPE_P (aptype));
>  
>  	/* Balanced out the &ap, usually added by build_va_arg.  */
> -	ap = build_fold_indirect_ref (ap);
> +	ap = build2 (MEM_REF, TREE_TYPE (aptype), ap,
> +		     build_int_cst (aptype, 0));
>  
>  	push_gimplify_context (false);
>  	saved_location = input_location;
> @@ -1053,7 +1056,7 @@ expand_ifn_va_arg_1 (function *fun)
>  	    if (chkp_function_instrumented_p (fun->decl))
>  	      chkp_fixup_inlined_call (lhs, expr);
>  
> -	    if (nargs == 3)
> +	    if (nargs == 4)
>  	      {
>  		/* We've transported the size of with WITH_SIZE_EXPR here as
>  		   the last argument of the internal fn call.  Now reinstate
> --- gcc/testsuite/gcc.dg/pr69162.c.jj	2016-01-07 15:27:10.215660347 +0100
> +++ gcc/testsuite/gcc.dg/pr69162.c	2016-01-07 15:27:47.127148736 +0100
> @@ -0,0 +1,12 @@
> +/* PR tree-optimization/69162 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +#include <stdarg.h>
> +
> +int
> +foo (void *a)
> +{
> +  va_list *b = a;
> +  return va_arg (*b, int);
> +}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)