re PR libgomp/35625 (schedule(guided) loops forever if ((end - start) % incr) != 0)

	PR libgomp/35625
	* iter.c (gomp_iter_guided_next_locked): If q > n, set end to ws->end.
	(gomp_iter_guided_next): Likewise.
	* testsuite/libgomp.c/pr35625.c: New test.

From-SVN: r133306

diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index 5440f59f726f551d618fef5cf14f1c7313c2ddb5..5c548844a7a1bc99432567265e905e65e92401d0 100644 (file)
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,10 @@
+2008-03-18  Jakub Jelinek  <jakub@redhat.com>
+
+       PR libgomp/35625
+       * iter.c (gomp_iter_guided_next_locked): If q > n, set end to ws->end.
+       (gomp_iter_guided_next): Likewise.
+       * testsuite/libgomp.c/pr35625.c: New test.
+
 2008-03-16  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
        * aclocal.m4: Regenerate.

diff --git a/libgomp/iter.c b/libgomp/iter.c
index 1a8a2a7d04fdd9d873377a4747db092ba13143bf..2d5dd2edd5a74f97343981b3be8f5a07d4c9f225 100644 (file)
--- a/libgomp/iter.c
+++ b/libgomp/iter.c
@@ -242,16 +242,16 @@ gomp_iter_guided_next_locked (long *pstart, long *pend)
   if (ws->next == ws->end)
     return false;
 
-  n = (ws->end - ws->next) / ws->incr;
+  start = ws->next;
+  n = (ws->end - start) / ws->incr;
   q = (n + nthreads - 1) / nthreads;
 
   if (q < ws->chunk_size)
     q = ws->chunk_size;
-  if (q > n)
-    q = n;
-
-  start = ws->next;
-  end = start + q * ws->incr;
+  if (q <= n)
+    end = start + q * ws->incr;
+  else
+    end = ws->end;
 
   ws->next = end;
   *pstart = start;
@@ -286,15 +286,15 @@ gomp_iter_guided_next (long *pstart, long *pend)
       if (start == end)
        return false;
 
-      n = (end - start) / ws->incr;
+      n = (end - start) / incr;
       q = (n + nthreads - 1) / nthreads;
 
       if (q < chunk_size)
        q = chunk_size;
-      if (q > n)
-       q = n;
-
-      nend = start + q * incr;
+      if (__builtin_expect (q <= n, 1))
+       nend = start + q * incr;
+      else
+       nend = end;
 
       tmp = __sync_val_compare_and_swap (&ws->next, start, nend);
       if (__builtin_expect (tmp == start, 1))

diff --git a/libgomp/testsuite/libgomp.c/pr35625.c b/libgomp/testsuite/libgomp.c/pr35625.c
new file mode 100644 (file)
index 0000000..f2978f9
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/pr35625.c
@@ -0,0 +1,18 @@
+/* PR libgomp/35625 */
+/* { dg-do run } */
+/* { dg-options "-std=c99" } */
+
+int
+main (void)
+{
+#pragma omp parallel
+  {
+    #pragma omp for schedule (guided, 10)
+      for (int i = 0; i < 1826; i += 10)
+       ;
+    #pragma omp for schedule (guided, 10)
+      for (int i = 0; i > -1826; i -= 10)
+       ;
+  }
+  return 0;
+}