Fix parloops gimple_uid usage
2015-10-09 Tom de Vries <tom@codesourcery.com>
* tree-parloops.c (reduction_phi): Handle cases that gimple_uid is 0 or
-1. Add assert that returned entry matches phi argument.
(parallelize_loops): Move calls to init_stmt_vec_info_vec and
free_stmt_vec_info_vec ...
(gather_scalar_reductions): ... here. Initialize gimple_uids of phis
with -1.
---
gcc/tree-parloops.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
@@ -237,9 +237,14 @@ reduction_phi (reduction_info_table_type *reduction_list, gimple *phi)
if (reduction_list->elements () == 0 || phi == NULL)
return NULL;
+ if (gimple_uid (phi) == (unsigned int)-1
+ || gimple_uid (phi) == 0)
+ return NULL;
+
tmpred.reduc_phi = phi;
tmpred.reduc_version = gimple_uid (phi);
red = reduction_list->find (&tmpred);
+ gcc_assert (red == NULL || red->reduc_phi == phi);
return red;
}
@@ -2392,6 +2397,9 @@ gather_scalar_reductions (loop_p loop, reduction_info_table_type *reduction_list
loop_vec_info simple_inner_loop_info = NULL;
bool allow_double_reduc = true;
+ if (!stmt_vec_info_vec.exists ())
+ init_stmt_vec_info_vec ();
+
simple_loop_info = vect_analyze_loop_form (loop);
if (simple_loop_info == NULL)
return;
@@ -2453,9 +2461,16 @@ gather_scalar_reductions (loop_p loop, reduction_info_table_type *reduction_list
destroy_loop_vec_info (simple_loop_info, true);
destroy_loop_vec_info (simple_inner_loop_info, true);
+ /* Release the claim on gimple_uid. */
+ free_stmt_vec_info_vec ();
+
/* As gimple_uid is used by the vectorizer in between vect_analyze_loop_form
- and destroy_loop_vec_info, we can set gimple_uid of reduc_phi stmts
- only now. */
+ and free_stmt_vec_info_vec, we can set gimple_uid of reduc_phi stmts only
+ now. */
+ basic_block bb;
+ FOR_EACH_BB_FN (bb, cfun)
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ gimple_set_uid (gsi_stmt (gsi), (unsigned int)-1);
reduction_list->traverse <void *, set_reduc_phi_uids> (NULL);
}
@@ -2603,7 +2618,6 @@ parallelize_loops (void)
gcc_obstack_init (&parloop_obstack);
reduction_info_table_type reduction_list (10);
- init_stmt_vec_info_vec ();
FOR_EACH_LOOP (loop, 0)
{
@@ -2695,7 +2709,6 @@ parallelize_loops (void)
n_threads, &niter_desc);
}
- free_stmt_vec_info_vec ();
obstack_free (&parloop_obstack, NULL);
/* Parallelization will cause new function calls to be inserted through
--
1.9.1
Hi, In tree-parloops.c:gather_scalar_reductions, we find the comment: ... /* As gimple_uid is used by the vectorizer in between vect_analyze_loop_form and destroy_loop_vec_info, we can set gimple_uid of reduc_phi stmts only now. */ reduction_list->traverse <void *, set_reduc_phi_uids> (NULL); ... However, the usage of gimple_uid seems to extend until the free_stmt_vec_info_vec call at the end of parallelize_loops (the pass top-level function). During free_stmt_vec_info_vec we test for gimple_uid == 0 in vinfo_for_stmt. By initializing all the phis in the function with -1 before using them in the reduct_phi stmts: ... destroy_loop_vec_info (simple_loop_info, true); destroy_loop_vec_info (simple_inner_loop_info, true); /* As gimple_uid is used by the vectorizer in between vect_analyze_loop_form and destroy_loop_vec_info, we can set gimple_uid of reduc_phi stmts only now. */ + basic_block bb; + FOR_EACH_BB_FN (bb, cfun) + for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + gimple_set_uid (gsi_stmt (gsi), (unsigned int)-1); reduction_list->traverse <void *, set_reduc_phi_uids> (NULL); ... we trigger a sigsegv in vinfo_for_stmt while trying to access stmt_vec_info_vec[4294967295 - 1]. This patch fixes that by moving the calls to init_stmt_vec_info_vec and free_stmt_vec_info_vec from parallelize_loops and gather_scalar_reductions. Furthermore, now that the gimple_uids are properly initialized, we can in reduction_phi: - handle 0 (new phi) and -1 (initialized) values, both meaning the phi's not in the table, and - assert that returned entries in fact match the phi argument. OK for trunk if bootstrap and reg-test passes? Thanks, - Tom