From bfe7ac89a0be108eaccfa277db28ed6141a3d5af Mon Sep 17 00:00:00 2001
From: Joost VandeVondele <vondele@gcc.gnu.org>
Date: Mon, 24 Aug 2015 11:01:25 +0000
Subject: [PATCH] re PR libgomp/66761 (libgomp: ThreadSanitizer: data race in
 libgomp)

        PR libgomp/66761
        PR libgomp/67303
        * iter.c (gomp_iter_dynamic_next): Employ an atomic load.
        (gomp_iter_guided_next): Idem.
        * iter_ull.c (gomp_iter_ull_dynamic_next): Idem.
        (gomp_iter_ull_guided_next): Idem.
        * config/linux/wait.h (do_spin): Idem.

From-SVN: r227119
---
 libgomp/ChangeLog           | 10 ++++++++++
 libgomp/config/linux/wait.h |  4 +++-
 libgomp/iter.c              |  4 ++--
 libgomp/iter_ull.c          |  4 ++--
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index 1d265b62e99..bd9111b86a9 100644
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,13 @@
+2015-08-24  Joost VandeVondele  <vondele@gnu.gcc.org>
+
+	PR libgomp/66761
+	PR libgomp/67303
+	* iter.c (gomp_iter_dynamic_next): Employ an atomic load.
+	(gomp_iter_guided_next): Idem.
+	* iter_ull.c (gomp_iter_ull_dynamic_next): Idem.
+	(gomp_iter_ull_guided_next): Idem.
+	* config/linux/wait.h (do_spin): Idem.
+
 2015-08-10  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* libgomp-plugin.h (enum offload_target_type): Remove
diff --git a/libgomp/config/linux/wait.h b/libgomp/config/linux/wait.h
index 7f57454a510..e561c2ddf6b 100644
--- a/libgomp/config/linux/wait.h
+++ b/libgomp/config/linux/wait.h
@@ -49,7 +49,9 @@ static inline int do_spin (int *addr, int val)
 {
   unsigned long long i, count = gomp_spin_count_var;
 
-  if (__builtin_expect (gomp_managed_threads > gomp_available_cpus, 0))
+  if (__builtin_expect (__atomic_load_n (&gomp_managed_threads,
+                                         MEMMODEL_RELAXED)
+                        > gomp_available_cpus, 0))
     count = gomp_throttled_spin_count_var;
   for (i = 0; i < count; i++)
     if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val, 0))
diff --git a/libgomp/iter.c b/libgomp/iter.c
index 0ceb41d909e..1def8bde066 100644
--- a/libgomp/iter.c
+++ b/libgomp/iter.c
@@ -218,7 +218,7 @@ gomp_iter_dynamic_next (long *pstart, long *pend)
 	}
     }
 
-  start = ws->next;
+  start = __atomic_load_n (&ws->next, MEMMODEL_RELAXED);
   while (1)
     {
       long left = end - start;
@@ -301,7 +301,7 @@ gomp_iter_guided_next (long *pstart, long *pend)
   long start, end, nend, incr;
   unsigned long chunk_size;
 
-  start = ws->next;
+  start = __atomic_load_n (&ws->next, MEMMODEL_RELAXED);
   end = ws->end;
   incr = ws->incr;
   chunk_size = ws->chunk_size;
diff --git a/libgomp/iter_ull.c b/libgomp/iter_ull.c
index b1cad84d4c8..1c2d118b631 100644
--- a/libgomp/iter_ull.c
+++ b/libgomp/iter_ull.c
@@ -219,7 +219,7 @@ gomp_iter_ull_dynamic_next (gomp_ull *pstart, gomp_ull *pend)
 	}
     }
 
-  start = ws->next_ull;
+  start = __atomic_load_n (&ws->next_ull, MEMMODEL_RELAXED);
   while (1)
     {
       gomp_ull left = end - start;
@@ -305,7 +305,7 @@ gomp_iter_ull_guided_next (gomp_ull *pstart, gomp_ull *pend)
   gomp_ull start, end, nend, incr;
   gomp_ull chunk_size;
 
-  start = ws->next_ull;
+  start = __atomic_load_n (&ws->next_ull, MEMMODEL_RELAXED);
   end = ws->end_ull;
   incr = ws->incr_ull;
   chunk_size = ws->chunk_size_ull;