From: Tom de Vries <Tom_deVries@mentor.com>
To: "gcc-patches@gnu.org" <gcc-patches@gnu.org>
Subject: [PATCH] Fix parloops gimple_uid usage
Date: Fri, 09 Oct 2015 21:11:00 -0000 [thread overview]
Message-ID: <56182D1D.2060106@mentor.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1751 bytes --]
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
[-- Attachment #2: 0001-Fix-parloops-gimple_uid-usage.patch --]
[-- Type: text/x-patch, Size: 2691 bytes --]
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(-)
diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 741392b..7366318 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -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
next reply other threads:[~2015-10-09 21:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-09 21:11 Tom de Vries [this message]
2015-10-12 10:04 ` Richard Biener
2015-11-20 15:57 ` [PATCH, PR68460] Always call free_stmt_vec_info_vec in gather_scalar_reductions Tom de Vries
2015-11-23 9:43 ` Richard Biener
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