On Wed, Jun 15, 2011 at 8:57 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> The following testcase is miscompiled e.g. on powerpc (not on x86_64/i686
> due to different ivopts choices), because estimate_numbers_of_iterations
> was called before assert_exprs are added to the IL and gets info cached
> until adjust_range_with_scev, where using the original SSA_NAMEs leads
> to problems where VR changes might not be propagated properly.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk/4.6? I'll work on followup improvements for the trunk
> afterwards.
Ok.
Thanks,
Richard.
> 2011-06-15 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/49419
> * tree-vrp.c (execute_vrp): Call init_range_assertions
> before estimate_numbers_of_iterations, call
> free_number_of_iterations_estimates before calling
> remove_range_assertions.
>
> * gcc.c-torture/execute/pr49419.c: New test.
>
> --- gcc/tree-vrp.c.jj 2011-05-31 08:03:10.000000000 +0200
> +++ gcc/tree-vrp.c 2011-06-15 17:25:32.000000000 +0200
> @@ -7730,14 +7730,14 @@ execute_vrp (void)
> rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
> scev_initialize ();
>
> + insert_range_assertions ();
> +
> /* Estimate number of iterations - but do not use undefined behavior
> for this. We can't do this lazily as other functions may compute
> this using undefined behavior. */
> free_numbers_of_iterations_estimates ();
> estimate_numbers_of_iterations (false);
>
> - insert_range_assertions ();
> -
> to_remove_edges = VEC_alloc (edge, heap, 10);
> to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
> threadedge_initialize_values ();
> @@ -7746,6 +7746,8 @@ execute_vrp (void)
> ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
> vrp_finalize ();
>
> + free_numbers_of_iterations_estimates ();
> +
> /* ASSERT_EXPRs must be removed before finalizing jump threads
> as finalizing jump threads calls the CFG cleanup code which
> does not properly handle ASSERT_EXPRs. */
> --- gcc/testsuite/gcc.c-torture/execute/pr49419.c.jj 2011-06-15
> 18:06:43.000000000 +0200
> +++ gcc/testsuite/gcc.c-torture/execute/pr49419.c 2011-06-15
> 18:05:18.000000000 +0200
> @@ -0,0 +1,38 @@
> +/* PR tree-optimization/49419 */
> +
> +extern void abort (void);
> +
> +struct S { int w, x, y; } *t;
> +
> +int
> +foo (int n, int f, int *s, int m)
> +{
> + int x, i, a;
> + if (n == -1)
> + return 0;
> + for (x = n, i = 0; t[x].w == f && i < m; i++)
> + x = t[x].x;
> + if (i == m)
> + abort ();
> + a = i + 1;
> + for (x = n; i > 0; i--)
> + {
> + s[i] = t[x].y;
> + x = t[x].x;
> + }
> + s[0] = x;
> + return a;
> +}
> +
> +int
> +main (void)
> +{
> + int s[3], i;
> + struct S buf[3] = { { 1, 1, 2 }, { 0, 0, 0 }, { 0, 0, 0 } };
> + t = buf;
> + if (foo (0, 1, s, 3) != 2)
> + abort ();
> + if (s[0] != 1 || s[1] != 2)
> + abort ();
> + return 0;
> +}
>
> Jakub
>
