From 78be3690e79eaa3f4f85c3d02f9ef95b472e5357 Mon Sep 17 00:00:00 2001
From: Joost VandeVondele <vondele@gcc.gnu.org>
Date: Mon, 24 Aug 2015 12:17:07 +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: r227122
---
 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 2f3ec02055b9..d59d80b47733 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.
+
 2015-07-16  Release Manager
 
 	* GCC 5.2.0 released.
diff --git a/libgomp/config/linux/wait.h b/libgomp/config/linux/wait.h
index 96d2fbe5f8c3..46a461553535 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 0ceb41d909e2..1def8bde0661 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 b1cad84d4c86..1c2d118b6318 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;