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.
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
