On Mon, 12 Feb 2018, Jakub Jelinek wrote:
> Hi!
>
> get_range_strlen fails to tell the caller that array_at_struct_end_p has
> been involved in cases like (&ptr->arr[0]), while it handles
> (ptr->arr). Fixed thusly, bootstrapped/regtested on x86_64-linux and
> i686-linux, ok for trunk?
Ok.
Richard.
> 2018-02-12 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/84339
> * gimple-fold.c (get_range_strlen): Set *FLEXP to true when handling
> ARRAY_REF where first operand is array_at_struct_end_p COMPONENT_REF.
> Formatting fixes.
>
> * gcc.c-torture/execute/pr84339.c: New test.
>
> --- gcc/gimple-fold.c.jj 2018-01-11 19:01:07.259442879 +0100
> +++ gcc/gimple-fold.c 2018-02-12 15:44:41.350214335 +0100
> @@ -1380,9 +1380,15 @@ get_range_strlen (tree arg, tree length[
> /* Set the minimum size to zero since the string in
> the array could have zero length. */
> *minlen = ssize_int (0);
> +
> + if (TREE_CODE (TREE_OPERAND (arg, 0)) == COMPONENT_REF
> + && type == TREE_TYPE (TREE_OPERAND (arg, 0))
> + && array_at_struct_end_p (TREE_OPERAND (arg, 0)))
> + *flexp = true;
> }
> else if (TREE_CODE (arg) == COMPONENT_REF
> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 1))) == ARRAY_TYPE)
> + && (TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 1)))
> + == ARRAY_TYPE))
> {
> /* Use the type of the member array to determine the upper
> bound on the length of the array. This may be overly
> @@ -1428,7 +1434,7 @@ get_range_strlen (tree arg, tree length[
> || integer_zerop (val))
> return false;
> val = wide_int_to_tree (TREE_TYPE (val),
> - wi::sub(wi::to_wide (val), 1));
> + wi::sub (wi::to_wide (val), 1));
> /* Set the minimum size to zero since the string in
> the array could have zero length. */
> *minlen = ssize_int (0);
> --- gcc/testsuite/gcc.c-torture/execute/pr84339.c.jj 2018-02-12
> 15:47:04.167243039 +0100
> +++ gcc/testsuite/gcc.c-torture/execute/pr84339.c 2018-02-12
> 15:46:48.363239868 +0100
> @@ -0,0 +1,30 @@
> +/* PR tree-optimization/84339 */
> +
> +struct S { int a; char b[1]; };
> +
> +__attribute__((noipa)) int
> +foo (struct S *p)
> +{
> + return __builtin_strlen (&p->b[0]);
> +}
> +
> +__attribute__((noipa)) int
> +bar (struct S *p)
> +{
> + return __builtin_strlen (p->b);
> +}
> +
> +int
> +main ()
> +{
> + struct S *p = __builtin_malloc (sizeof (struct S) + 16);
> + if (p)
> + {
> + p->a = 1;
> + __builtin_strcpy (p->b, "abcdefg");
> + if (foo (p) != 7 || bar (p) != 7)
> + __builtin_abort ();
> + __builtin_free (p);
> + }
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
