On Thu, 15 Feb 2018, Jakub Jelinek wrote:
> Hi!
>
> The function calls get_addr_base_and_unit_offset on 2 trees, but
> that can return NULL if the unit offset is not constant.
> The conditional tests just one of them for non-NULL and operand_equal_p
> ICEs if one argument is NULL, so depending on the uninitialized poly_int64
> (get_addr_base_and_unit_offset doesn't touch it if it returns NULL),
> we either ICE in operand_equal_p or are lucky and dstoff is equal to lhsoff
> and just valgrind complains.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
Ok.
Richard.
> 2018-02-15 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/84383
> * tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Don't look at
> dstoff nor call operand_equal_p if dstbase is NULL.
>
> * gcc.c-torture/compile/pr84383.c: New test.
>
> --- gcc/tree-ssa-strlen.c.jj 2018-02-09 06:44:29.993809176 +0100
> +++ gcc/tree-ssa-strlen.c 2018-02-14 16:38:36.981713666 +0100
> @@ -1878,6 +1878,7 @@ maybe_diag_stxncpy_trunc (gimple_stmt_it
> poly_int64 lhsoff;
> tree lhsbase = get_addr_base_and_unit_offset (lhs, &lhsoff);
> if (lhsbase
> + && dstbase
> && known_eq (dstoff, lhsoff)
> && operand_equal_p (dstbase, lhsbase, 0))
> return false;
> --- gcc/testsuite/gcc.c-torture/compile/pr84383.c.jj 2018-02-14
> 17:33:21.972803287 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr84383.c 2018-02-14
> 17:32:37.639803918 +0100
> @@ -0,0 +1,14 @@
> +/* PR tree-optimization/84383 */
> +
> +struct S { char *s; };
> +void bar (struct S *);
> +
> +void
> +foo (int a, char *b)
> +{
> + struct S c[4];
> + bar (c);
> + __builtin_strncpy (c[a].s, b, 32);
> + c[a].s[31] = '\0';
> + bar (c);
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
